Apparatus and process having an oscillating angled plate and / or a fixed horizontal plate for forming fiber reinforced cement panels having controlled thickness - Patents.com

Abstract

The production line (10) and process includes a movable carrier web (14) for transporting panels and a device (93) for controlling the thickness of a fiber-reinforced cementitious panel slurry formed on the web (14) but not yet hardened. The thickness control device (93) may include an angled rigid plate (95) for contacting a downstream end (202) of the angled plate (95) with the slurry on the movable carrier web (14) and a mounting stand (97) for mounting the angled rigid plate (95). The thickness control device (93) may include a flat horizontal plate (201) at a fixed height on the movable carrier web (14) so ​​that the entire lower surface of the horizontal plate (201) contacts a facer (444) on the slurry on the movable carrier web (14). Alternatively, the thickness control device (93) may include an angled plate (93) and a horizontal plate (201) that contacts the facer (444).

Description

[Technical field]

[0001] The present invention relates to a continuous process and associated equipment for producing structural panels using a hardening slurry, and more particularly to a thickness control device for controlling thickness to reduce thickness variation during the manufacture of fiber reinforced cementitious panels (FRC panels) in which fibers are combined with a quick hardening slurry to provide flexural strength. These FRC panels are also referred to herein as fiber reinforced concrete panels or structural cement panels (SCP panels). [Background technology]

[0002] Fiber-reinforced concrete panels (FRC panels) can be formed by laying alternating layers of reinforcing glass fibers and cementitious slurry. A thin layer of the slurry is deposited on a line. A fiberglass chopper then deposits a layer of chopped glass on top of the slurry. A double-disk embedding roller then embeds the glass fibers into the slurry as disclosed. For example, the process can include four layering stations located in series on a conveyor belt, where the product then reaches an overall average thickness. Two vibrating screed plates then skim off the top of the panel, but the layered mass is still somewhat fluid, providing a smoothing effect on the top surface. An exemplary process is disclosed in U.S. Patent No. 7,794,221 to Dubey. This process is repeated several times until the panel is at the desired thickness.

[0003] U.S. Patent No. 7,445,738 to Dubey et al. discloses a multi-layer process for producing fiber reinforced concrete panels (FRC panels), referred to as structural cementitious panels, that includes: (a.) providing a moving web; (b.) one of: (i) depositing a first layer of individual loose fibers onto the web, followed by depositing a layer of a hardenable slurry onto the web, or (ii) depositing a layer of a hardenable slurry onto the web; (c.) depositing a second layer of individual loose fibers onto the slurry; (d.) actively embedding the second layer of individual loose fibers into the slurry to distribute the fibers throughout the slurry; and (e.) repeating steps (ii) through (d.) until a desired number of layers of hardenable fiber reinforced slurry is obtained and the fibers are distributed throughout the panel.

[0004] U.S. Patent No. 8,038,790 to Dubey et al. discloses structural cement panels that employ one or more layers of a continuous phase resulting from hardening an aqueous mixture of calcium sulfate alpha hemihydrate, hydraulic cement, coated expanded perlite particle filler, optional additional fillers, active pozzolan, and lime. The coated perlite has a particle size of 1-500 microns, a median diameter of 20-150 microns, and an effective particle density (specific gravity) of less than 0.50 g / cc. The panel is reinforced with fibers, such as alkali-resistant glass fibers.

[0005] US 2018 / 0036912 to Dubey et al. discloses a single layer process for producing a slurry for cementitious panels with high reinforcing fiber concentration. These fiber reinforced cementitious panels are made on a panel production line with the edges wrapped in a surface reinforcing web such as a nonwoven fiber mat, which can be a polypropylene mat or a glass fiber mat. The process applies a first nonwoven fiber mat onto the surface of a moving seamless belt and a second nonwoven fiber mat onto the hardened fiber slurry mixture.

[0006] Other aspects of the single layer process for producing a slurry for cementitious panels having high reinforcing fiber concentrations are disclosed below.

[0007] U.S. Published Patent Application No. 2018 / 0036912A1 to Dubey et al., entitled “METHODS OF MAKING FIBER REINFORCED CONCRETE PANELS USING A CONTINUOUS PROCESS”; No. 10,272,399 to Dubey et al., entitled "A METHOD FOR PRODUCING FIBER REINFORCED CEMENTITIOUS SLURRY USING A MULTI-STAGE CONTINUOUS MIXER" (also published as US2018 / 0036693 A1); U.S. Published Patent Application No. 2018 / 0036911A1 to Dubey et al., entitled “CONTINUOUS MIXER AND METHOD OF MIXING REINFORCED FIBERS WITH CEMENTITIOUS MATERIALS”; U.S. Published Patent Application No. 2018 / 0036909A1 to Dubey et al., entitled "HEADBOX AND FORMING STATION FOR FIBER REINFORCED CEMENTITIOUS PANEL PRODUCTION."

[0008] The manufacturing process of these structural FRC panels includes two separate production lines: a forming line, and a finishing line. During panel formation on the forming line, the panel thickness is thicker than the finished product. This excess material is provided to ensure that the entire panel, including thickness variations, meets the desired minimum thickness to ensure there are no blemishes on the finished panel. However, when the panel passes the finishing line, the excess material is removed so that the entire panel is at the desired minimum thickness without thickness variations. Therefore, typically, the final thickness and surface of a fiber reinforced structural cement panel (also known as a fiber reinforced concrete panel) is the result of a separate polishing and finishing process. This practice has several drawbacks. Due to the constraints imposed by the forming process, the product is thicker than the desired product thickness. Additional polishing is required on the panel finishing line to achieve the correct panel thickness. The formed product has dimensions (length and width) larger than the desired final product dimensions. This requires additional processing steps on the panel finishing line to cut the panels to the final dimensions. The production efficiency of the panels is reduced due to the additional time and steps for finishing.

[0009] It is desirable to make the panels thinner because later in the process the panels will be ground down to the desired thickness and the ground-down material will be wasted. However, if one tries to make it thinner on average there will be localized areas that are thinner than the desired thickness which results in the entire panel being unsalable, so it is now more economical to make it very thick and then grind it down to the desired thickness.

[0010] Suzuki et al., US 6,702,966, discloses a thickness control device 4 having a vibrating leveller 2a on a smooth forming pressure plate 2b for smoothing the surface of a slurry A'. The smooth forming pressure plate 2b is tiltable and is set to slope downward and have an angle of incidence of 5 to 10 degrees, preferably 7 degrees. An angle of less than 2 degrees causes the formation of bubbles (see col. 4, ll. 36-58).

[0011] Jones, US 8,163,352 (US 2009 / 0043780) discloses a production line having a smoothing device, also called a vibrating edger bar, for gently smoothing the top surface of a deposited slurry layer before depositing each subsequent fibrous top layer.

[0012] Stivender's US 8,038,915 (2010 / 0132870) discloses a flexible curved smoothing sheet or shroud disposed transverse to the direction of travel of a formed fiber panel slurry, the flexible sheet designed to float on the surface of the formed panel without tearing or otherwise damaging the surface of the highly fiber reinforced surface layer of the panel (see abstract).

[0013] However, there remains a need for additional thickness control in the production of fiber reinforced cementitious panels. Summary of the Invention

[0014] The present invention provides a thickness control device and method for reducing thickness variation during the formation of fiber reinforced cementitious panels. Minimizing or eliminating grinding, polishing, and / or edge finishing should result in significant cost savings in raw materials and other operational costs such as labor and maintenance. Specific cost savings include reduced raw material usage, less waste disposal, less wear and tear, and improved production rates on the finishing line. There may also be other benefits, such as a reduction in the amount of distortion during the panel curing process, which further reduces waste costs.

[0015] The present invention features a thickness control device having an adjustable but fixed position for applying uniform pressure across the top surface of the formed fiber reinforced cementitious panel as it exits the headbox and / or as it exits the embedding device of the slurry forming station and / or further downstream of the headbox and / or embedding device. The thickness control device levels and smooths the surface of the FRC panel and controls the panel thickness without damaging the FRC panel. As used in this disclosure and depending on the context, those skilled in the art will understand that the term "panel" can include a panel precursor, which is a cementitious product that has not yet been formed or cut into separate panels.

[0016] The present invention provides a fiber reinforced cement panel (FRC) production line, the fiber reinforced cement panel (FRC) production line comprising: A movable carrier web; a support frame for supporting a movable carrier web, the panels being transported on the movable carrier web having a travel direction relative to the support frame; 1. A thickness control device for controlling the thickness of a formed, but not yet cured or cut, fiber reinforced cementitious structural panel, comprising: a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on a moving carrier web; A thickness control device, An angled rigid plate; a mounting frame for mounting an angled rigid plate on a support frame for the moving carrier web; a flat, rigid support bed underlying the angled, rigid plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing slurry and to withstand a downward force imparted by the angled, rigid plate, preferably with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; the angled rigid plate has a laterally upstream rear wall, a laterally downstream bottom wall extending downstream from a lower end of the laterally upstream rear wall, an open side wall, and an open top, the bottom wall lower surface having a flat horizontal profile, the laterally upstream rear wall meets the downstream bottom wall to form a curved transition section aligned laterally with respect to a direction of travel of the moving carrier web, the laterally upstream rear wall meets the laterally downstream bottom wall to form an angle in the range of 60°-120°, preferably 70°-110°, and most preferably 80°-100°, the laterally upstream rear wall is directed from the curved transition section upwardly away from the moving carrier web, and the laterally downstream bottom wall is directed from the curved transition section downwardly towards the moving carrier web; a thickness control device mounted on the mounting stand such that a lateral upstream rear wall of the angled rigid plate is transverse to a direction of travel of the moving carrier web; a vibrator attached to a laterally upstream rear wall of the angled rigid plate; a mounting stand for fixedly positioning the downstream end of the lateral bottom wall at a height of 0.1 to 2 inches, preferably 0.2 to 1.1 inches, on the movable carrier web, for fixedly but adjustably maintaining the height of the angled plate on the movable carrier web, and for fixedly but adjustably maintaining the angle of the angled plate relative to the movable carrier web within the range of 5° to 30°, typically the angle being within the range of 10° to 25°; a downstream end of the transverse bottom wall is transverse to a direction of travel of the slurry and the moving carrier web; a downstream end of the lateral bottom wall extends laterally across the moving web; The downstream end of the bottom lateral wall may be contacted with the fiber-containing cementitious slurry as it is transported on the moving carrier web.

[0017] The flat rigid support bed beneath the angled rigid plate may be beneath or above the carrier web. The carrier web is typically a seamless belt. The deflection is less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches, perpendicular to the horizontally moving carrier web.

[0018] The downstream end of the lateral bottom wall therefore extends laterally across a path for the slurry on the moving web, and the angle of the angled plate relative to the moving carrier web places the downstream end of the lateral bottom wall lower than the upstream end of the lateral bottom wall.

[0019] The mounting stand typically mounts an angled rigid plate on or around a support for the advancing carrier web at a location after the carrier web exits the headbox and / or embedding device of the slurry forming station. The back wall (vertical leg) and bottom wall (horizontal leg) of the angled rigid plate are made of lightweight metal, for example, relatively short and as wide as the formed fiber reinforced cementitious slurry panel. The horizontal leg of the angled rigid plate is generally disposed transversely to the direction of travel of the panels on the carrier web. A vibrator is mounted on the upper surface of the back wall to impart vibrations to the angled rigid plate, which vibrates the surface of the angled rigid plate during use.

[0020] With respect to the angled plate, the term "rigid" means having sufficient strength to resist bending or flexing when contacted with the slurry according to the present invention.

[0021] The lateral bottom wall (also known as the horizontal leg) of the angled rigid plate is set at a fixed small inlet angle, for example, in the range of 5°-30°, typically 10°-25°, with respect to the moving web and to the slurry moving underneath. Therefore, only the surface of the downstream end portion of the angled rigid plate contacts the upper surface of the slurry to form the panel. This allows for a stable and controlled contact with the fiber-containing slurry as the angled rigid plate levels and smoothes the slurry surface. The height and angle adjustment and support system of the angled rigid plate are configured such that the height of the angled rigid plate and the contact angle of the angled rigid plate with the fiber-containing slurry are fixed but adjustable during this contact.

[0022] The shape of the angled plate may be L-shaped, but need not be a perfect L-shape, i.e., the angle "θ" between the laterally upstream rear wall and the laterally downstream bottom wall may not necessarily be 90°. The angle between the rear wall and the bottom wall is fixed, but may vary from obtuse to acute. For example, the angle between the two walls may range from 60° to 120°, preferably 70° to 110°, and most preferably 80° to 100°. Furthermore, the transition geometry between the rear wall and the bottom wall may be sharp or curved. The laterally upstream rear wall and the laterally downstream bottom wall may be a single piece forming the angle "θ" or two pieces fixedly attached, for example by welding, forming the angle "θ".

[0023] The present invention also provides a continuous process for controlling the thickness of a formed, but not yet cured, fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers, comprising: in a fiber reinforced cementitious panel production line as described above, transporting the panels on a movable carrier web having a direction of travel relative to a support frame for supporting the movable carrier web; contacting the formed, but not yet cured, fiber reinforced cementitious panel, including the slurry and embedded chopped fibers, with a downstream end of a thickness control device; A thickness control device, An angled rigid plate; a mounting frame for mounting the angled rigid plate on a support frame for the moving carrier web; a flat, rigid support bed underlying the angled, rigid plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing slurry and to withstand a downward force imparted by the angled, rigid plate, preferably with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; the angled rigid plate has a laterally upstream rear wall, a laterally downstream bottom wall extending downstream from a lower end of the laterally upstream rear wall, an open side wall, and an open top, the bottom wall lower surface having a flat horizontal profile, the laterally upstream rear wall meets the downstream bottom wall to form a curved transition section aligned laterally with respect to a direction of travel of the moving carrier web, the laterally upstream rear wall meets the laterally downstream bottom wall to form an angle in the range of 60°-120°, preferably 70°-110°, and most preferably 80°-100°, the laterally upstream rear wall is directed from the curved transition section upwardly away from the moving carrier web, and the laterally downstream bottom wall is directed from the curved transition section downwardly towards the moving carrier web; the angled plate is mounted on the mounting stand such that a lateral upstream rear wall of the angled plate is transverse to a direction of travel of the moving carrier web; a vibrator is attached to the lateral upstream rear wall of the angled plate; A mounting stand maintains a fixed but adjustably height of the angled plate relative to the moving carrier web to fixedly position the downstream end of the bottom wall at a height of 0.1 to 2 inches, preferably 0.2 to 1.1 inches, above the moving carrier web, and maintains a fixed but adjustably angle of the angled plate relative to the moving carrier web less than 30°, typically an angle in the range of 5° to 30°, preferably 10° to 25°, such that the downstream end of the bottom wall contacts the fiber-containing slurry transported on the moving carrier web to control the thickness of the fiber-containing slurry.

[0024] The flat rigid support bed beneath the angled rigid plate may be below or above the carrier web, which is typically a seamless belt.

[0025] Quite surprisingly, it has been found that a more uniform panel surface profile across the panel width is obtained when the outer edge of the bottom wall of the angled rigid plate assembly is located below the top surface of the panel being formed. Thus, the outer edge of the bottom wall of the angled rigid plate assembly is located approximately 0.01 inches to 0.25 inches below the top surface of the panel being formed.

[0026] A thickness control device, typically including an angled rigid plate and a mounting frame, can be used in a multi-layer or single layer process to produce fiber reinforced cementitious panels (FRC panels).

[0027] In a first version of the multi-layer process, the process involves an initial deposition of a layer of loosely distributed chopped fibers or cementitious slurry on a moving web, followed by deposition of fibers on the slurry layer. An embedding device thoroughly mixes the newly deposited fibers into the slurry so that the fibers are distributed throughout the slurry to form a fiber-containing cementitious slurry, followed by the addition of additional layers of slurry, then chopped fibers, followed by further embedding with additional embedding devices. This process is repeated for each layer of the panel as desired. A thickness control device is used downstream of one or more embedding devices to contact the layer of fiber-containing cementitious slurry to level and control the thickness of the layer. Downstream is an apparatus for cutting the hardened slurry into FRC panels.

[0028] In the second version of the multi-layer process, the first version of the process is modified by depositing an additional layer of loose fibers on the existing fiber-containing cementitious slurry after the embedding device, followed by a layer of slurry and then another layer of fibers. The fiber / slurry / fiber combination is then subjected to embedding for thorough mixing of the fibers in the slurry. A thickness control device is used downstream of one or more embedding devices before the additional layer of loose fibers is deposited on the existing fiber-containing cementitious slurry. The thickness control device is therefore in contact with the existing layer of fiber-containing cementitious slurry to level and control the thickness of the layer.

[0029] In a single layer process for making fiber reinforced concrete (FRC) panels, a fiber-containing slurry is mixed upstream of a headbox (slurry feed station) of a panel production line. This fiber-containing cementitious slurry is then fed into a slurry feeder (known as a "headbox"), which deposits the fiber-containing cementitious slurry directly onto a moving carrier web panel production line in a uniform layer of 0.125 to 2 inches thick, preferably 0.25 to 1 inch thick, typically 0.40 to 0.75 inches thick, to produce a fiber reinforced cementitious panel. In a process for producing cementitious panels from a fiber slurry mixture of the present invention that produces panels having up to a single layer of fiber reinforced cementitious slurry, the moving surface preferably moves at a speed of 1 to 100 feet per minute, more preferably 5 to 50 feet per minute. As one skilled in the art will appreciate, other speeds above 100 feet per minute are also contemplated. Downstream is an apparatus for cutting the hardened slurry into FRC panels.

[0030] Thus, the thickness control device of the present invention may be used downstream of a headbox as part of an apparatus for producing cementitious panels having up to a single layer of fiber reinforced cementitious composition, the apparatus including a conveyor-type frame supporting a moving web, and a mixer system in operative association with the frame for mixing water, cementitious material, and fibers, configured to feed the resulting fiber slurry mixture to the headbox, and configured to deposit a hardenable fiber-containing cementitious slurry onto the moving web.

[0031] In particular, the thickness control device of the present invention comprising an angled rigid plate can be applied downstream of a headbox, preferably immediately downstream of the headbox, in a continuous process for depositing a uniform layer of cementitious slurry containing reinforcing fibers from the headbox onto a traveling web; depositing a cementitious slurry containing reinforcing fibers on an interior surface of a tightly mounted headbox; depositing a cementitious slurry containing reinforcing fibers from a headbox onto a web proceeding as a continuous layer; the reinforcing fiber containing cementitious slurry deposited from the headbox has a slump of 4 to 11 inches as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter, and the resulting reinforcing fiber containing cementitious slurry also has a viscosity of less than 45,000 centipoise, preferably less than 30,000 centipoise, more preferably less than 15,000 centipoise, and most preferably less than 10,000 centipoise, as measured using a Brookfield Viscometer, Model DV-II+Pro with a Spindle HA4 attachment operating at a speed of 20 RPM, and typically the resulting fiber slurry mixture has a viscosity of at least 1500 centipoise; depositing; contacting a formed, but not yet cured, fiber reinforced cementitious panel, the fiber reinforced cementitious panel including a cementitious slurry containing reinforcing fibers, with a downstream end of a thickness control device; A thickness control device, An angled rigid plate; a mounting frame for mounting an angled rigid plate on a support frame for the moving carrier web; a flat, rigid support bed underlying the angled, rigid plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing slurry and to withstand a downward force imparted by the angled, rigid plate, preferably with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; the angled rigid plate has a laterally upstream rear wall, a laterally downstream bottom wall extending downstream from a lower end of the laterally upstream rear wall, an open side wall, and an open top, the bottom wall lower surface having a flat horizontal profile, the laterally upstream rear wall meets the downstream bottom wall to form a curved transition section aligned laterally with respect to a direction of travel of the moving carrier web, the laterally upstream rear wall meets the laterally downstream bottom wall to form an angle in the range of 60°-120°, preferably 70°-110°, and most preferably 80°-100°, the laterally upstream rear wall is directed from the curved transition section upwardly away from the moving carrier web, and the laterally downstream bottom wall is directed from the curved transition section downwardly towards the moving carrier web; the angled plate is mounted on the mounting stand such that the lateral upstream rear wall of the angled plate is transverse to the direction of travel of the moving carrier web; a vibrator is attached to the lateral upstream rear wall of the angled plate; A mounting stand maintains a fixed but adjustably height of the angled plate relative to the moving carrier web to fixedly position the downstream end of the bottom wall at a height of 0.1 to 2 inches above the moving carrier web, and maintains a fixed but adjustably angle of the angled plate relative to the moving carrier web less than 30°, typically an angle between 5° and 30°, and preferably within the range of 10° to 25°, such that the downstream end of the bottom wall contacts the fiber-containing slurry transported on the moving carrier web to control the thickness of the fiber-containing slurry.

[0032] In another aspect of the invention, the invention may provide an FRC panel production line comprising a horizontal thickness control device comprising a horizontally oriented upper forming plate having an adjustable but fixed height to apply uniform pressure across the top surface of the formed fiber reinforced cementitious panel as it exits the headbox and / or embedding device of the slurry forming station and / or further downstream of the headbox and / or embedding device to level and smooth the surface of the panel without damaging the panel and to control the panel thickness.

[0033] More specifically, the present invention provides an FRC panel production line and method for FRC panel production that uses a facer, such as a glass mat, installed across the width of the forming surface (belt / plate) and the rigid horizontal upper forming plate to reduce thickness variations during the formation of the fiber reinforced cementitious panel. In the novel invention, a facer, such as a glass mat, is applied to one or both sides of the structural panel during the forming process. A horizontally oriented, rigid horizontal upper forming plate is then used to form the slurry of glass fiber / cementitious material of the FRC panel to the desired thickness. The position of the entire rigid horizontal upper forming plate is fixed to provide a fixed gap between the lower surface of the rigid horizontal upper forming plate and the moving carrier web below. It is therefore not a "floating plate". Due to its horizontal orientation, the entire lower surface of the rigid horizontal upper forming plate is in contact with the fiber-containing slurry passing under the forming plate, not just the downstream end as in the angled rigid plate described above. This process produces panels with low thickness variation (e.g., + / - 0.1 inches, preferably + / - 0.05 inches) and then allows the panels to be formed at a reduced average thickness, e.g., to a target average thickness of 0.80 inches, without localized smearing below 0.72 inches. Less raw material can therefore be used while producing the same finished product. Additional savings are possible from items such as reduced waste disposal costs, reduced equipment wear, increased production speeds, and the like. As previously mentioned, one or two facers may be used in the present invention. Additionally, the one or two facers may be temporary, such that the facers are removed before or during finishing operations, or the facers may remain on the finished product.

[0034] The top forming plate is rigid and flat, and the carrier below the horizontal forming plate needs to be a rigid carrier web or a rigid flat bottom forming plate because the facer and fiber cementitious slurry passing below the horizontal forming plate exert pressure on the carrier below. If the fiber cementitious slurry presses against a thin support frame below the moving carrier web, calibre results will be poor.

[0035] Therefore, the present invention provides a fiber reinforced cementitious panel production line, the fiber reinforced cementitious panel production line comprising: A movable carrier web; a support frame for supporting a movable carrier web, the panels being transported on the movable carrier web having a travel direction relative to the support frame; a means for applying a facer, such as a glass mat, onto the fiber-containing cementitious slurry on a moving carrier web, the means for applying the facer being positioned across the width of the forming surface of the moving carrier web; 1. A horizontal thickness control device for controlling the thickness of a formed, but not yet cured, fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry, the fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers, on a moving carrier web, the device comprising: A thickness control device, a rigid horizontal upper forming plate, the rigid horizontal upper forming plate having a flat bottom surface, an upstream end, and a downstream end; a forming plate mounting frame for mounting a rigid horizontal upper forming plate in a horizontal orientation on a support frame for the movable carrier web, the rigid horizontal upper forming plate being mounted to the forming plate mounting frame; a horizontal thickness control device comprising: a flat, rigid support bed underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; a forming plate mounting frame for fixedly but adjustably maintaining the height of the rigid horizontal upper forming plate above the movable carrier web to fixedly position the flat bottom surface at a height of 0.1 to 2 inches, preferably 0.2 to 1.1 inches, above the movable carrier web, and for maintaining the rigid horizontal upper forming plate parallel to the movable carrier web; an upstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; a downstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; The entire flat bottom surface can contact a facer on the fiber-containing slurry as it is transported on the moving carrier web.

[0036] A flat rigid support bed beneath the rigid horizontal upper forming plate may underlie or overlie a carrier web, which is typically a seamless belt.

[0037] The present invention also provides a process for making a fiber reinforced cementitious panel, comprising: transporting a fiber-containing slurry for the panels on a moving carrier web, the moving carrier web being supported by a support frame, the panels being transported on the moving carrier web having a travel direction relative to the support frame; applying a facer, such as a glass mat, onto the fiber-containing cementitious slurry on the moving carrier web across the width of the forming surface of the moving carrier web to cover the forming surface; passing a forming surface covered with a facer under a horizontal thickness control device for controlling a thickness of a formed but not yet cured fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on a moving carrier web; A thickness control device, a rigid horizontal upper forming plate (e.g., horizontal forming plate 446), the rigid horizontal upper forming plate having a flat bottom surface, an upstream end, and a downstream end; a forming plate mounting frame for mounting a rigid horizontal upper forming plate in a horizontal orientation on a support frame for the movable carrier web, the rigid horizontal upper forming plate being mounted to the forming plate mounting frame; a flat, rigid support bed underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; and controlling a thickness of the formed but uncured fiber reinforced cementitious panel by contacting the formed but uncured fiber reinforced cementitious panel covered with a facer, the fiber containing cementitious slurry, with a bottom surface of a rigid horizontal upper forming plate; a mounting frame for fixedly but adjustably maintaining the height of the rigid horizontal upper forming plate on the movable carrier web and for maintaining the rigid horizontal upper forming plate parallel to the movable carrier web to fixedly position the flat bottom surface at a height of 0.1 to 2 inches above the movable carrier web; an upstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; a downstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; The entire flat bottom surface contacts a facer on the fiber-containing slurry as it is transported on the moving carrier web.

[0038] A flat rigid support bed beneath the rigid horizontal upper forming plate may underlie or overlie a carrier web, which is typically a seamless belt.

[0039] If desired, the present invention provides an FRC panel production line and method for FRC panel production that reduces thickness variations during the formation of a fiber reinforced cementitious panel with the use of the angled plate, the forming top surface, and a facer such as a glass mat placed across the width of the horizontal forming plate described above. Such an FRC panel production line and method contacts a fiber-containing slurry with the angled plate described above, then applies a facer such as a glass mat to the top surface of the FRC panel during the forming process, and then runs the facer-covered fiber-containing slurry under the rigid horizontal upper forming plate. Optionally, the production line and method may also apply a facer such as a glass mat to the underside of the structural panel upstream of the headbox during the forming process.

[0040] The present invention also provides a process for using this production line.

[0041] The present invention also provides an embodiment in which the panel has a fabric facer on one or both flat surfaces of the panel. The facer provides the panel with a remarkably flat surface profile and uniform thickness. It has also been surprisingly found that the fabric facer improves the exterior weatherability of the final composite. Characteristic features of FRC panels having a fabric facer include, among others: -Excellent weather resistance and durability -Improved aesthetics and clean surfaces -Improved readability / visibility of printing on panel surface - The ability to provide two separate usable surfaces for various applications and uses - one with a facer, the other without. For example, the without-facer surface is best suited for adhesion of various types of roofing membranes and foamed plastics. The without-facer surface is also suitable for applications where it is desirable to have a simple plain concrete appearance, such as interior wall and ceiling applications. On the other hand, the with-facer surface is particularly suitable for applications where excellent adhesion is required for cementitious basecoats and other coating materials. Interior and exterior walls, as well as subfloors, are some applications where it may be desirable to have at least one panel surface with a facer. -Improved surface durability against impact loads -Excellent adhesion surface -Ability to differentiate products by utilizing fabrics with different colors and / or patterns -Increased flexibility for application of value-added functional coatings such as waterproofing coatings, air and water barrier coatings, architectural coatings etc.

[0042] Unless otherwise stated, all percentages in this specification, if any, are by weight. [Brief description of the drawings]

[0043] [Figure 1] FIG. 2 is an elevational view of an FRC panel production line of the present invention for producing a multi-layer FRC panel having angled plates. [Figure 1A] FIG. 2 is a schematic diagram of a mixer feeding a headbox of the FRC panel production line of FIG. [Diagram 2] 1 shows the caliper control device when used in contact with a slurry on a web. [Diagram 3] FIG. 2 shows a perspective view of a thickness control device in an operating position in the direction of travel of a web transporting a slurry panel. [Figure 4]1 shows an angled plate with the downstream end of the angled plate submerged in a slurry on a production line. [Figure 4A] 1 shows an angled plate with curved corners with the downstream end of the angled plate immersed in a slurry on a production line. [Diagram 5] 13 shows another perspective view of the thickness control device in an upward position on the web line. [Figure 6] 1 is a fragmentary vertical cross-section of a structural cementitious panel produced according to the present procedure. [Figure 7] FIG. 2 is an elevational view of a second version of an FRC panel production line plate of the present invention for producing a multi-layer FRC panel having angled plates. [Figure 8] FIG. 2 is an elevational view of a third version of the FRC panel production line for producing the single layer FRC panel with angled plates of the present invention. [Figure 9] FIG. 2 is an elevational view of a fourth version of the FRC panel production line of the present invention, the production line of FIG. 1 modified to include an angled plate applying facer and a fixed forming plate. [Figure 9A] 10 shows a first enlarged perspective view of a portion of the FRC panel production line of FIG. 9 for applying facers and using fixed forming plates. [Figure 9B] 10 shows a second enlarged perspective view of a portion of the FRC panel production line of FIG. 9 for applying facers and using fixed forming plates. [Figure 9C] 10 shows a forming plate mounting frame for mounting a rigid horizontal upper forming plate in a horizontal orientation on a support frame for a moving carrier web for the fixed forming plate of the FRC panel production line of FIG. [Figure 9D] 1 shows the beveled upstream end of the horizontal forming plate. [Figure 10] FIG. 13 is an elevational view of a fifth version of the FRC panel production line with angled plates of the present invention modified to apply a facer and use fixed forming plates. [Figure 10A] FIG. 11 is an elevational view of a sixth version of the FRC panel production line with angled plates of the present invention modified to apply facers, use fixed forming plates, and fold the edge of the lower facer under the edge of the upper facer to encase the FRC panel. [Figure 10B] FIG. 10B shows a perspective view of an FRC panel produced by the production line of FIG. 10A. [Figure 10C] FIG. 1 shows a cross-sectional side view of a mat of polymeric fibers having a laminated composite structure of one spun-bonded layer of fibers and a relatively impermeable meltblown layer of fibers. [Figure 10D] 1 illustrates a top perspective view of an embodiment of an FRC panel completely encased within a mat of facer material, showing the edges of the panel covered by the facer and illustrating the overlap of the rear and front facers. [Figure 10E] A side view of a portion of a typical production line is shown with side wipers installed on both sides of the line and in front of the forming plate to prevent slurry leakage. An optional agitator mounted on the side of the wipers is also shown. An optional agitator installed under the floor plate of the forming line just behind the forming plate to keep the slurry head active and fluid is also shown. [Figure 11] 13A-13C show schematic diagrams of an example formed sample panel that was cut into four pieces upon curing. [Figure 11A] 1 shows the standard deviation in inches and the difference in maximum and minimum thickness in inches of formed panels at different experimental conditions for samples measured in the cross-machine direction with and without the angled plate thickness control device of the present invention. Control #1 and Control #2 are experimental conditions not of the present invention for one example herein. [Figure 11B] 13A-13C are schematic diagrams of an example formed sample panel that was cut into eight pieces upon curing. [Figure 12] 1 illustrates the cross-sectional thickness profile in inches of a cementitious panel formed in the cross-machine direction without the use of the angled plate thickness control device of the present invention. [Figure 13]1 illustrates the cross-sectional thickness profile in inches of a cementitious panel formed in the cross-machine direction using the angled plate thickness control device of the present invention. [Figure 14] In order to show the standard deviation and the difference in maximum and minimum thickness of the panels formed at different experimental conditions for samples measured in the cross-machine direction with and without the angled plate thickness control device of the present invention, information on panel thickness measurements in inches across the cross-machine direction is provided, where Control #1 and Control #2 are experimental conditions without the angled plate thickness control device of the present invention. [Figure 15] To show the standard deviation and the difference in maximum and minimum thickness of the panels formed under different experimental conditions in Table 1 for one example herein with and without the angled plate thickness control device of the present invention, Control #1 and Control #2 are experimental conditions without the angled plate thickness control device of the present invention. [Figure 16] 1 illustrates the cross-machine cross-sectional thickness profile in inches of a cementitious panel formed without the use of the angled plate thickness control device of the present invention. [Figure 17] FIG. 1 shows the cross-sectional profile of a formed cementitious panel using the angled plate thickness control device of the present invention for control sample example #R3 herein, which was made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate. [Figure 18] FIG. 1 shows the cross-sectional profile of the formed cementitious panel for Example #R3 herein measured in the cross-machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate. [Figure 19]FIG. 1 shows the cross-sectional profile of the formed cementitious panel for Example #R3 herein measured in the machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate. [Figure 20] FIG. 1 shows the cross-sectional profile of the formed cementitious panel for Example #R4 herein measured in the cross-machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate. [Figure 21] FIG. 1 shows the cross-sectional profile of the formed cementitious panel for Example #R4 herein measured in the machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate. [Figure 22] FIG. 1 shows the cross-sectional profile of the formed cementitious panel for Example #R1 herein measured in the cross-machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate. [Figure 23] FIG. 1 shows the cross-sectional profile of the formed cementitious panel for Example #R1 herein measured in the machine direction of a control sample made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate. [Figure 24] FIG. 1 shows the cross-sectional profile of the formed cementitious panel for Example #T1 herein measured in the cross-machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention. [Diagram 25] FIG. 13 shows the cross-sectional profile of the formed cementitious panel for Example #T1 herein measured in the machine direction of trial specimens made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention. [Figure 26]FIG. 13 shows the cross-sectional profile of the formed cementitious panel for Example #T2 herein measured in the cross-machine direction. [Figure 27] FIG. 13 shows the cross-sectional profile of the formed cementitious panel for Example #T2 herein measured in the machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention. [Figure 28] FIG. 13 shows the cross-sectional profile of the formed cementitious panel for Example #T4 herein measured in the cross-machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention. [Figure 29] FIG. 13 shows the cross-sectional profile of the formed cementitious panel for Example #T4 herein measured in the machine direction of trial specimens made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention. [Diagram 30] 1 shows an FRC panel with glass mat facer in an exterior weathering exposure field located in Northern Illinois, USA. [Figure 31A] A close-up view (front side) of an FRC panel without a facer after 9 months of exterior weathering exposure is shown. [Figure 31B] FIG. 1 shows a close-up view (front side) of an FRC panel with glass mat facer after 9 months of exterior weathering exposure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] I. Fiber Cement Mixtures for the Present Invention The present invention works with a variety of fiber cement mixtures produced containing cement, water, and other cement additives.

[0045] The fiber cement mixture produced by the method and apparatus of the present invention is an aqueous slurry that can be derived from various hardening cementitious slurries. For example, such an aqueous slurry can be a hydraulic cement-based composition. ASTM defines "hydraulic cement" as a cement that hardens or hardens by chemical interaction with water and can do so in water. Examples of suitable hydraulic cements are Portland cement, calcium aluminate cement (CAC), calcium sulfoaluminate cement (CSA), geopolymers, magnesium oxychloride cement (Sorel cement), and magnesium phosphate cement. A preferred geopolymer is based on the chemical activation of Class C fly ash.

[0046] Although calcium sulfate hemihydrate sets and hardens by chemical interaction with water, in the context of the present invention, it is not included within the broad definition of hydraulic cement. However, calcium sulfate hemihydrate may be included in the fiber cement mixture produced by the method and apparatus of the present invention. Thus, such aqueous slurries can also be based on calcium sulfate cement, such as gypsum cement or calcined gypsum. Gypsum cement is primarily calcined gypsum (calcium sulfate hemihydrate). It is customary in the industry to refer to calcined gypsum as gypsum cement.

[0047] Fiber cement mixtures may contain pozzolanic materials such as silica fume, finely divided amorphous silica, a product of silicon metallurgy, and ferrosilicon alloy manufacture. It characteristically has a very high silica content and a low alumina content. A variety of other natural and man-made materials have been cited as having pozzolanic properties, including pumice, perlite, diatomaceous earth, tuff, volcanic earth, metakaolin, microsilica, and ground granular blast furnace slag. Fly ash also has pozzolanic properties. Fiber cement mixtures may contain other lightweight fillers such as ceramic and / or polymeric microspheres and / or expanded perlite.

[0048] However, one use of the fiber cement slurry made by the present method is to produce fiber reinforced concrete (FRC) having reinforcing fibers such as glass fibers, particularly alkali resistant glass fibers. Thus, the cementitious slurry used in the present invention is preferably comprised of varying amounts of Portland cement, gypsum, aggregate, water, accelerators, plasticizers, superplasticizers, foaming agents, fillers, and / or other ingredients well known in the art or described in the patents listed below, which are incorporated by reference. The relative amounts of these ingredients, including the removal or addition of some of the above, may be varied to suit the intended use of the final product.

[0049] Water-reducing admixture additives can optionally be included in the fiber cement mixture to improve the fluidity of the hydraulic slurry, e.g., plasticizers, superplasticizers, etc. Such additives disperse the molecules in solution so that they can move more easily relative to one another, thereby improving the overall fluidity of the slurry. Plasticizers are generally made from lignosulfonates, which are by-products of the paper industry. Superplasticizers are generally made from sulfonated naphthalene condensates or sulfonated melamine formaldehyde, or based on polycarboxyl ethers. Water-reducing additives can be present in an amount of 0% to 5%, preferably 0.5 to 5%, by weight of the wet final fiber slurry mixture.

[0050] No. 6,620,487 to Tonyan et al., incorporated herein by reference in its entirety, discloses a reinforced, lightweight, dimensionally stable structural cement panel (SCP) that uses a continuous phase core resulting from the hardening of an aqueous mixture of calcium sulfate alpha hemihydrate, hydraulic cement, active pozzolan, and lime. The continuous phase is reinforced with alkali-resistant glass fibers, contains ceramic microspheres or a blend of ceramic and polymeric microspheres, or is formed from an aqueous mixture having a weight ratio of water to reactive powder of 0.6 / 1 to 0.7 / 1, or a combination thereof. At least one exterior surface of the SCP panel may include a hardened continuous phase that is reinforced with glass fibers to improve nailability and contains sufficient polymer spheres or is made with a ratio of water to reactive powder that provides an effect similar to that of polymer spheres, or a combination thereof.

[0051] Various formulations for composite slurries used in the current process are also shown in U.S. Patent No. 7,841,148 to Tonyan et al., which is incorporated herein by reference. A typical formulation includes, on a dry basis, as reactive powders, 35-75% by weight (typically 45-65 or 55-65% by weight) calcium sulfate alpha hemihydrate, 20-55% by weight (typically 25-40% by weight) of hydraulic cement such as Portland cement, 0.2-3.5% by weight of lime, and 5-25% by weight (typically 10-15% by weight) of active pozzolan. The continuous phase of the panel will be uniformly reinforced with alkali-resistant glass fibers and contain 20-50% by weight of uniformly distributed lightweight filler particles selected from the group consisting of ceramic microspheres, glass microspheres, fly ash cenospheres, and perlite. An example of a formulation for the composite slurry includes, based on total dry ingredients, 42-68 wt.% reactive powder, 23-43 wt.% ceramic microspheres, 0.2-1.0 wt.% polymeric microspheres, and 5-15 wt.% alkali-resistant glass fibers.

[0052] U.S. Patent No. 8,038,790 to Dubey et al. describes a composite composite material comprising, on a dry basis, 50-95 weight percent reactive powder, 1-20 weight percent coated hydrophobic expanded perlite particles uniformly dispersed therein as a lightweight filler, the coated hydrophobic expanded perlite particles having a diameter in the range of about 1-500 microns (micrometers), a median diameter of 20-150 microns (micrometers), and an effective particle density (specific gravity) of less than about 0.50 g / cc, and 0-25 weight percent hollow ceramic microspheres. Another example of a formulation is provided for a composite slurry comprising an aqueous mixture of a cementitious composition comprising 3-16% by weight of alkali resistant glass fiber uniformly distributed for reinforcement, the reactive powders comprising 25-75% by weight calcium sulfate alpha hemihydrate, 10-75% by weight of hydraulic cement comprising Portland cement, 0-3.5% by weight of lime, and 5-30% by weight of active pozzolan, and the panel has a density of 50-100 pounds per cubic foot.

[0053] If desired, the compositions used in the single and multi-layer processes of the present invention can have a weight ratio of water to reactive powder of from 0.20 / 1 to 0.90 / 1, preferably from 0.25 / 1 to 0.70 / 1, or from 0.4 / 1 to 0.7 / 1.

[0054] The fibers can be separate fibers or chopped fibers made from different reinforcing fiber materials including fiberglass, polymeric materials such as polypropylene, polyethylene, polyvinyl alcohol, carbon, graphite, aramid, ceramic, steel, cellulosic or natural fibers such as jute or sisal, or combinations thereof. The length of the fibers is about 2 inches or less, more preferably 1.5 inches or less.

[0055] For the single layer process, the fiber cement mixture contains sufficient water to achieve the desired slump test value and viscosity in combination with the other components of the fiber cement mixture.

[0056] Production line and method having thickness control device using angled plates - Patents.com II. The first version of the production line Referring now to FIG. 1, a production line for FRC panels is shown diagrammatically and generally designated 10. Production line 10 includes a support frame or forming table 12 having a plurality of legs 13 or other supports. Included on support frame 12 is a moving carrier 14, such as a seamless rubber-like conveyor belt having a smooth, water-impermeable surface, although porous surfaces are also envisioned. As is well known in the art, support frame 12 can be made from at least one table-like segment, which may include designated legs 13 or other support structures. Support frame 12 also includes a main drive roll 16 at a distal end 18 of the frame, and an idler roll 20 at a proximal end 22 of the frame. At least one belt tracking and / or tensioning device 24 is also typically provided to maintain a desired tension and positioning of carrier 14 relative to rolls 16, 20. As moving carrier 14 advances in a direction "T" from proximal end 22 to distal end 18, FRC panels are continuously produced.

[0057] In this production line 10, a carrier web 26 of kraft paper, release paper, or a plastic carrier is provided to support the slurry prior to curing and may be placed over the web 14 to protect the slurry and / or keep it clean.

[0058] However, it is also contemplated that rather than a continuous carrier web 26, individual sheets (not shown) of a relatively rigid material, such as, for example, a sheet of polymeric plastic, may be placed over the carrier 14.

[0059] It is also contemplated that the FRC panels produced by the present line 10 may be formed directly on the carrier 14. In this latter situation, at least one belt washing unit 28 is provided. The carrier 14 moves along the support frame 12 by a combination of motors, pulleys, belts or chains that drive a main drive roll 16, as is known in the art. It is contemplated that the speed of the carrier 14 may be varied to suit the product being made.

[0060] A. Shredder In the present invention, production of fiber reinforced concrete (FRC) panels, also known as structural cement panels (SCP panels), begins by depositing a layer of loose, chopped fiber 30, approximately one inch in size, onto a plastic carrier on a carrier web 26. A variety of fiber deposition and chopping devices are contemplated by the present line 10. For example, a typical system employs a rack 31 that holds several spools 32 of fiberglass cord, from each of which a length or thread of fiber 34 is fed to a chopping station or apparatus, also referred to as a chopper 36. Typically, many strands of fiberglass are fed at each of the chopping stations.

[0061] The chopper 36 includes a rotating bladed roll 38 from which radially project blades 40 that extend laterally across the width of the carrier 14 and are disposed in close contact and rotating relationship with an anvil roll 42. Preferably, the bladed roll 38 and the anvil roll 42 are disposed in relatively close relationship such that rotation of the bladed roll 38 also rotates the anvil roll 42, and vice versa. The anvil roll 42 is also preferably covered with a resilient support material against which the blades 40 chop the cord 34 into segments. The spacing of the blades 40 on the roll 38 determines the length of the chopped fibers. As seen in FIG. 1, the chopper 36 is disposed above the carrier 14 near the proximal end 22 to maximize productive use of the length of the production line 10. As the fiber strands 34 are chopped, the fibers fall loosely onto the carrier web 26.

[0062] B. Slurry Mixer The production line 10 includes a slurry preparation and feed section 2 (FIG. 1A). The slurry preparation and feed section 2 includes a slurry feed station or slurry feeder or slurry headbox, generally designated 44, and a source of slurry, which is a wet mixer 47. The slurry feeder 44 receives a supply of slurry 46 from the wet mixer 47 for depositing the slurry 46 onto the chopped fibers on the carrier web 26. It is also envisioned that the process may begin with an initial deposition of the slurry onto the carrier 14.

[0063] Examples of some suitable slurry mixers 47 are those commonly used in the cement mortar and concrete industry that may also be used in the present invention. For example, ICRI Guideline No. 320.5R-2014, Technical Guidelines, Pictorial Atlas of Concrete Repair Equipment, International Concrete Repair Institute, May 2014, incorporated by reference, may be used in the present invention to prepare cementitious slurries. These include horizontal shaft mixers, tumble mortar mixers, rotary drum stationary mixers, pan type mixers, rotating tub rotary paddle mixers, planetary paddle mixers, horizontal shaft mixer and pump combinations, and vertical shaft mixer and pump combinations. The horizontal shaft mixer and pump combinations and the vertical shaft mixer and pump combinations are continuous mixers.

[0064] C. Slurry supply device 1-1A, as described above, an embodiment of a slurry feed apparatus, generally designated 44 and also referred to as a slurry feed station, slurry feeder or slurry headbox, receives a feed of slurry 46 from a wet mixer 47.

[0065] The slurry dispenser 44 includes a main metering roll 48 disposed transversely to the direction of travel "T" of the carrier 14. A companion or backup roll 50 is disposed in close, parallel, rotational relationship to the metering roll 48. The slurry 46 is deposited in a nip 52 between the two rolls 48, 50.

[0066] The slurry feeder 44 also has a gate 132 mounted on a sidewall 54 of the slurry feeder 44 and mounted adjacent to the surface of the metering roll 48 to form a nip 55 therebetween. As seen in FIG. 1A, the gate 132 is above the metering roll 48 such that the nip 55 is between the gate 132 and an upper portion of the roll 48. The rolls 48, 50 and the gate 132 are disposed in sufficiently close relationship such that the nip 55 holds a supply of slurry 46 while the rolls 48, 50 rotate relative to one another. The gate 132 includes a vibrator (not shown). As seen in FIG. 1A, the metering roll 48 rotates from the nip 52 to the nip 55.

[0067] Typically, the metering roll 48 has a larger diameter than the companion roll 50, although other sizes are contemplated.

[0068] Also, typically one of the rolls 48, 50 has a smooth stainless steel outer surface while the other, preferably the companion roll 50, has a resilient, non-stick material covering its outer surface.

[0069] In particular, the gate 132 comprises a blade 132A mounted on a vibrating gate support shaft / bar (not shown) and, optionally, a stiffening member (not shown) mounted on the vibrating gate support shaft / bar. The gate blade 132A is typically fabricated from 16-12 gauge stainless steel sheet metal.

[0070] The gate 132 is vibrated by a rotary vibrator (not shown) mounted on the opposite side of the blade of the stiffening member. The stiffening member is attached to the vibrating gate support shaft and to the underside of the vibrating gate 132. If a stiffening member is not provided, then the rotary vibrator may be attached to the gate support shaft or other suitable part of the gate 132. The vibration means is typically a pneumatic rotary ball vibrator. The level of vibration may be controlled with a conventional air regulator (not shown).

[0071] The gate 132 may be mounted to the sidewall 54 of the headbox 44 by a support system (not shown) to allow the blade position to be adjusted horizontally as well as vertically. The support system includes a pivot pin attached to each end of the gate support shaft and seated within an adjustable mount attached to the sidewall 54 of the slurry feeder. A version of the adjustable mount has a pivot yoke seated within a U-shaped member. A screw passes through the upwardly extending leg of the U-shaped mount to allow forward and aft adjustment of the pivot yoke, and in turn, the position of the gate 132. A bolt is also provided through a hole in the U-shaped member to allow up and down adjustment of the pivot yoke, and in turn, the position of the gate 132.

[0072] Preferably, the vibrating gate 132 may be pivotally adjusted by a pivot adjustment system (not shown) to vary the gap "D" (FIG. 1A) between the gate 132 and the metering roll 48.

[0073] The vibrating gate 132 helps prevent significant build-up of the slurry 46 above the gate 132 and controls the thickness of the slurry 46 deposited on the metering roll 48 .

[0074] Typically, the slurry dispenser 44 has a pair of relatively rigid sidewalls 54 (one shown) that are preferably made from or coated with a non-stick material such as a TEFLON® material or the like. The sidewalls 54 prevent the slurry 46 poured into the nip 52 from exiting the sides of the slurry dispenser 44. Preferably, the sidewalls 54, which are secured to the support frame 12 (FIG. 1), are disposed in close proximity to the ends of the rolls 48, 50 to retain the slurry 46. However, the sidewalls 54 are not too close to the ends of the rolls to impede rotation of the rolls.

[0075] The slurry dispenser 44 deposits a uniform layer of slurry 46 on the moving carrier web 26. A preferred layer thickness is in the range of about 0.05 inches to 0.35 inches (0.13 to 0.9 cm), e.g., about 0.08 inches to 0.3 inches. However, where four layers are preferred in the structural panels produced by the production line 10, and a preferred build panel is approximately 0.75 inches, a particularly preferred slurry layer thickness is in the range of 0.15 to 0.25 inches. However, where the target panel build thickness is approximately 0.84 inches, the standard layer thickness is typically closer to about 0.21 inches at each of the four forming stations.

[0076] Therefore, the relative distance "D" (FIG. 1A) between the vibrating gate 132 and the main metering roll 48 can be adjusted to vary the thickness of the deposited slurry 46. The nip distance "D" between the gate 132 and the metering roll 48 is typically maintained at a distance of about 1 / 8 to about 3 / 8 inch (about 0.318 to about 0.953 cm). However, this can be adjusted based on the viscosity and thickness of the slurry 46, as well as the desired thickness of the slurry to be deposited on the web 26.

[0077] Slurry 46 is delivered to the slurry feeder 44 through a hose 56 or similar conduit having a first end 60 (FIG. 1A) in fluid communication with an outlet of a slurry mixer or reservoir 47. A second end 62 of the hose 56 is connected to a laterally reciprocating, cable-driven, fluid-powered dispenser 64 (FIG. 1A) of a type well known in the art. Thus, the slurry flowing from the hose 56 is poured laterally into the feeder 44 in a reciprocating manner to fill a reservoir 57 defined by the rolls 48, 50 and sidewall 54 of the slurry feeder 44. Rotation of the metering roll 48 draws a layer of slurry 46 from the reservoir 57.

[0078] Another feature of the present feeder apparatus 44 is that the main metering roll 48 and the companion roll 50 are both driven in the same direction to minimize the opportunity for the slurry to prematurely set on their respective moving exterior surfaces. A drive system (not shown), including a fluid powered, electric or other suitable motor, is connected to the main metering roll 48 or the companion roll 50 to drive the rolls in the same direction, which is clockwise when viewed in Figures 1 and 1A. As is well known in the art, either one of the rolls 48, 50 may be driven and the other roll may be connected via pulleys, belts, chains and sprockets, gears or other known power transmission techniques to maintain a positive and common rotational relationship.

[0079] The slurry dispenser 44 has a doctor blade 134 (FIG. 1A) positioned between the primary metering roll 48 and the carrier web 26 to ensure that the relatively thin slurry 46 is thoroughly deposited such that a continuous curtain or sheet of slurry is uniformly directed within a distance of about 1.0 to about 1.5 inches (2.54 to 3.81 cm) of the carrier web 26. The doctor blade 134 ensures that the slurry 46 uniformly covers the fiberglass fibrous layer on the carrier web 26 and does not progress back toward the nip 52 and dispenser reservoir 57. The doctor blade 134 also helps keep the primary metering roll 50 from prematurely setting the slurry 46.

[0080] The doctor blade 134 is mounted on a doctor blade support shaft (not shown) mounted on a doctor blade tension arm pivotally mounted on an adjustable pivot mount attached to the support frame or sidewall 54 of the slurry feeder 44. The shaft or bar is mounted to the sidewall 54 of the slurry feeder 44 above the metering roller 48. The doctor blade 134 is biased toward the roll 48 by a tension spring having a first end attached to the shaft or bar and a second end attached to the free end of the doctor blade tension arm. The doctor blade 134 is therefore held in position adjacent the outer surface of the metering roll 48 by the tension arm and tension spring. The position of the doctor blade 134 can be adjusted by adjusting the adjustable pivot mount attached to the support frame or sidewall 54 of the slurry feeder 44.

[0081] Doctor blade 134 serves to remove the slurry from the surface of metering roll 48 and collect the slurry 46 in a uniform layer or curtain, directing the slurry 46 downward in the direction of web travel to a point on the web about 1.0 to 1.5 inches (92.54 to 3.81 cm) above the fiberglass layer to uniformly cover the fiberglass layer with slurry 46.

[0082] The reciprocating distribution mechanism 64, gate 132, and doctor blade 134 are described in more detail in U.S. Patent No. 7,754,052 to Frank et al., entitled "PROCESS AND APPARATUS FOR FEEDING CEMENTITIOUS SLURRY FOR FIBER-REINFORCED STRUCTURAL CEMENT PANELS," which is incorporated herein by reference in its entirety. Other embodiments of slurry feed apparatus may be used as known in the art. One such apparatus is disclosed in U.S. Patent No. 8,770,139 to Frank et al., entitled "APPARATUS FOR FEEDING CEMENTITIOUS SLURRY ONTO A MOVING WEB," which is incorporated herein by reference in its entirety.

[0083] D. Treatment Downstream of the Slurry Feed Unit Referring again to FIG. 1, other operational components of the FRC panel production line will now be briefly described, all of which are described in more detail in the following documents, all of which are incorporated by reference in their entireties:

[0084] U.S. Patent No. 6,986,812 to Dubey et al., entitled "SLURRY FEED APPARATUS FOR FIBER-REINFORCED STRUCTURAL CEMENTITIOUS PANEL PRODUCTION"; Porter's U.S. Patent No. 7,182,589, entitled "EMBEDMENT DEVICE FOR FIBER-ENHANCED SLURRY"; No. 7,445,738 to Dubey et al., entitled "MULTI-LAYER PROCESS AND APPARATUS FOR PRODUCING HIGH STRENGTH FIBER-REINFORCED Structural Cementitious Panels"; No. 7,475,599 to Frank et al., entitled "WET SLURRY THICKNESS GAUGE AND METHOD FOR USE OF SAME"; U.S. Patent No. 7,513,768 to Porter et al., entitled "EMBEDMENT ROLL DEVICE"; No. 7,513,963 to Frank et al., entitled "METHOD FOR WET MIXING CEMENTITIOUS SLURRY FOR FIBER-REINFORCED STRUCTURAL CEMENT PANELS"; U.S. Patent No. 7,524,386 to George et al., entitled "METHOD FOR WET MIXING CEMENTITIOUS SLURRY FOR FIBER-REINFORCED STRUCTURAL CEMENT PANELS"; and Dubey's U.S. Patent No. 7,670,520, entitled "MULTI-LAYER PROCESS AND APPARATUS FOR PRODUCING HIGH STRENGTH FIBER-REINFORCED Structural Cementitious Panels With Enhanced Fiber Content."

[0085] E. Embedded Devices A variety of embedding devices are contemplated, including, but not limited to, vibrators, sheep's foot rollers, and the like. However, Figure 1 shows that embedding device 70 includes at least one pair of generally parallel shafts 76 mounted transversely to the direction of travel of carrier web 14 on frame 12. Each shaft 76 includes a plurality of relatively large diameter discs 76 axially separated from one another on the shaft by smaller diameter discs (not shown).

[0086] During production of SCP panels (FRC panels), the shaft 76 and discs 74 rotate together about the longitudinal axis of the shaft 76. As is well known in the art, one or both of the shafts 76 may be powered, and if only one is powered, the other may be driven by a belt, chain, gear drive or other known power transmission techniques to maintain a corresponding direction and speed relative to the driven shaft. The discs 74 of each of the adjacent, preferably parallel shafts 76 overlap and intermesh with one another to create a "kneading" or "massaging" action in the slurry that embeds previously deposited fibers 68. In addition, the close, intermeshing rotational relationship of the discs 74 prevents accumulation of the slurry 46 on the discs, in effect creating a "self-cleaning" action that significantly reduces production line downtime due to premature hardening of the slurry mass.

[0087] The intermeshing relationship of the disks 74 on the shaft 76 includes a close, adjacent arrangement of opposing peripheries of a smaller diameter spacer disk (not shown) and a relatively larger diameter main disk 74, which also facilitates a self-cleaning action. Because the disks 74 rotate in close proximity to one another (but preferably in the same direction), particles of the slurry are less likely to become trapped within the device and harden prematurely. By providing two sets of disks 74, laterally offset from one another, the slurry 46 is subjected to multiple disruptive actions, creating a "kneading" action and further embedding the fibers 68 within the slurry 46.

[0088] F. Thickness Control Once the fibers 68 are embedded, the first layer 77 of the panel 92 is complete. Typically, the height or thickness of the first layer 77 is within the approximate range of about 0.05 inches to 0.35 inches (0.13 to 0.9 cm). Preferably, the height or thickness of the first layer 77 is within the approximate range of 0.08 to 0.3 inches. This range has been found to provide the desired strength and stiffness when combined with similar layers in an FRC panel (SCP panel). However, other thicknesses are envisioned depending on the end intended use of the FRC panel (SCP panel).

[0089] The first layer 77 then contacts a thickness control device 93 of the present invention for controlling the thickness of the formed, but not yet cured, first layer 77 of fiber reinforced cementitious panel layers comprising a fiber-containing cementitious slurry including a cementitious material and embedded chopped fibers on the movable carrier web 26. The thickness control device 93 comprises an angled rigid plate 95 and a U-shaped mounting stand 97 for mounting the angled rigid plate 95 on the support frame or forming table 12 for the movable carrier web 26. The mounting stand 97 has opposed upright members 99 (only one is shown in FIG. 1 for clarity) and tiltable lateral mounting members 101 with opposed ends mounted to each upright member 99 at a fixed but adjustable angle relative to the movable carrier web 26 and at a fixed but adjustable height above the movable web 26. The mounting frame 97 also has a connector plate 103 having an upper end portion attached to the lateral mounting member 101 and a lower end portion attached to the rear wall of the angled rigid plate 95. A vibrator (vibration motor) 105 is also mounted to the rear wall of the angled rigid plate 95.

[0090] 1 shows the forming table 12, seamless belt 14, and carrier web 26, as well as optional bottom support plates 46A, 46B. The production line 10 provides a flat, rigid support bed beneath the angled, rigid plate that is sufficiently adapted and configured to support the fiber-containing slurry and to withstand the downward force imparted by the angled, rigid plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches.

[0091] A flat rigid support bed is provided to counter the downward force of the facer-covered fiber-containing slurry passing under the rigid horizontal upper forming plate 446 and can be, for example, one of the following:

[0092] If it is sufficiently rigid, the forming table 12; a forming table 12 provided below the carrier belt 14 and further supported by a rigid bottom forming plate 46A; a rigid panel used on the carrier belt 14 under or in place of the carrier web 26; The seamless belt 14 may be supported by rollers that are sufficiently rigid, or There may be a break in the forming table 12 and a rigid lower forming plate 46A is placed at the break directly below the portion of the seamless belt below the upper forming plate 446.

[0093] As mentioned above, it is also envisioned that rather than a continuous carrier web 26, individual sheets of relatively rigid material (not shown), such as, for example, sheets of polymeric plastic, may be placed on the carrier 14. These may also provide a flat, rigid support bed.

[0094] 2, 3, 4 and 5 show details of the construction of the thickness control device 93.

[0095] 2 is a schematic diagram of an angled vibrating plate 95, typically made of metal, with a coupling unit 204 for attaching a vibrator (vibration motor) 105 (see FIG. 1) to impart vibration to the plate. The angled vibrating metal plate 95 has an angled cross section with a back wall 200, a bottom wall 201, and a functional downstream edge 202 that is placed in the cementitious slurry at a certain depth ("D1", see FIG. 4) during operation to impart vibration to the slurry. Screws 203 are provided for attaching the coupling unit 204 to the back wall 200 of the angled plate 95. The angled plate 95 is typically made of metal.

[0096] 3 is a schematic diagram of a typical U-shaped mounting frame 97 of a thickness control device 93 for mounting an angled vibrating metal plate 95 and a vibrator (vibration motor) 105 (see FIG. 1) on a production line 10 for fiber reinforced cementitious panels. The U-shaped mounting frame 97 has upright members 99 fixedly attached to a stationary frame crosspiece 220. The U-shaped mounting frame 97 also has tiltable lateral mounting members 101 movably attached to the upright members 99. The tiltable lateral mounting members 101 have opposing ends each rotatably mounted to a respective metal plate 206 having holes for angle adjustment.

[0097] A typically rectangular, U-shaped metal mounting frame 97 made of modular metal channels, typically 4" x 4", that can be easily connected through slots and bolts or screws is shown in FIG. 3. A pair of screw jacks 212 with individual rotating wheels 214 and handles are mounted on either side of the forming surface to adjust the height of the vibrating metal plate above the forming surface and level the plate parallel to the forming surface. As shown in FIG. 3, for adjustment of the angle of the vibrating metal plate 95 with the forming surface, metal rods, typically 0.5" in diameter, are locked into specific angular positions by holes in metal plates 206 mounted on two sides of the mounting frame 97 in a plane perpendicular to the forming surface. Thus, each of the opposing ends of the tiltable lateral mounting members 101 are engaged with holes selected for the angle adjustment of the plates 206 to fixedly set the angle of the tiltable lateral mounting members 101 with respect to the movable carrier web 26 and with respect to the slurry on the movable carrier web 26. When the angle of the tiltable lateral mounting member 101 is adjusted and set, the angle of the angled vibrating metal plate 95 of the tiltable lateral mounting member 101, which is mounted at angle "α" (alpha) of the tiltable lateral mounting member 101, is similarly adjusted and set. Figure 3 also shows a location 205 on the coupling unit 204 for mounting a vibration motor.

[0098] To aid in adjusting the angle, the tiltable lateral mounting members 101 include handles 208 for lifting the vibratory plate up and down. The handles 208 are typically metal in the form of a pipe or rod, typically rectangular and 1 inch by 1 inch in cross section, but can be circular or other cross-sectional shapes, and are attached to the central frame piece crosspiece 101 to allow rotation on an axis perpendicular to the forming direction in the forming plane, as shown in Figure 3, to disengage for replacement, cleaning, or a maintenance mechanism to lift the plate off the production line.

[0099] The mounting mechanism 97 described above typically keeps the vibratory plate at a set fixed height from the forming surface (belt / plate) across its width so that the functional edge of the plate remains inside the surface of the slurry at a depth of 0.05 inches or more and the plate does not adjust its own height with the inflow of material.

[0100] FIG. 4 illustrates the angle "α" (alpha) of the bottom wall 201 of the angled rigid plate 95 relative to the surface of the moving carrier web 26. FIG. 4 illustrates the angle "β" (beta) of the bottom wall 201 of the angled rigid plate 95 relative to the surface of the slurry 77 when present on the moving carrier web 26. For purposes of this specification, the angles "α" (alpha) and "β" (beta) are equal. FIG. 4 also illustrates the depth "D1" at which the downstream end 202 of the bottom wall 201 of the angled rigid plate 95 is immersed in the surface of the slurry 77 on the moving carrier web 26. The angled plate angle "α" (alpha) and angle "β" (beta) are between 5° and 30°, and typically the angles "α" (alpha) and "β" (beta) are in the range of 10° to 25°.

[0101] The metal plate 206 travels vertically up and down the upright member 99 along the channel 210 in the upright member 99 and the stationary frame crosspiece 2209 of the frame 97. As the metal plate 206 travels vertically, the tiltable lateral mounting member 101 travels vertically with the plate 206. To raise and lower the height of the tiltable lateral mounting member 101, the U-shaped mounting frame 97 has jack screws 212 and rotating wheels 214 (one shown) for moving the jack screws 212. When mounted to the tiltable lateral mounting member 101, the angled oscillating metal plate 95 travels vertically with the tiltable lateral mounting member 101.

[0102] FIG. 5 shows a fixed, vibrating, lightweight metal plate setup to reduce thickness variation during the formation of a fiber-reinforced cementitious panel across the width of the forming surface. FIG. 5 shows a vibrator (vibration motor) 105 attached to a coupling unit 204. The rear end coupling unit 204 is attached to the rear wall of the angled vibrating metal plate 95. FIG. 4 shows that the top wall of the coupling unit is attached to a connector plate 103 having an upper end portion attached to the lateral mounting member 101 and a lower end portion attached to the rear wall of the angled rigid plate 95. An elastomeric shock absorber 212A is between the lower end of the connector plate 103 and the top wall of the coupling unit 204.

[0103] The thickness control device 93 of the present invention solves the problem of producing cementitious panels with reduced thickness variation so as to reduce processing steps during formation.

[0104] The thickness control device 93 of the present invention provides a mechanism to impart vibration to the forming slurry in a plane parallel to the forming surface (belt / plate) to spread the material evenly over the surface in a manner that reduces thickness variation. The present invention provides a method for reducing thickness variation during the formation of fiber reinforced cementitious panels by the use of a vibrating light metal plate fixed across the width of the forming surface to impart vibration by contact with the surface or cementitious slurry containing fibers for reinforcement.

[0105] G. Angled Plate The angled vibratory plate 95 of the present invention typically has the following features:

[0106] The angled plate 95 is typically made from a metal, preferably a magnesium alloy, although aluminum, titanium, steel and other metal alloys may also be used.

[0107] The cross-section of the angled plate 95 is generally angled, although other cross-sections that provide a flat or curved surface in contact with the slurry and provide structural rigidity may also be utilized.

[0108] The shape of the angled plate 95 can be L-shaped, but need not be a perfect L-shape, i.e., the angle between the rear wall and the bottom wall does not necessarily always have to be 90°. The angle between the two walls can range from obtuse to acute. For example, the angle between the two walls can range from 60° to 120°, preferably 70° to 110°, and most preferably 80° to 100°. Furthermore, the transition geometry of the bent transition section between the rear wall and the bottom wall can be sharp or curved.

[0109] FIG. 4A shows angled rigid plate 195, which is a version of angled rigid plate 95 that has been modified to have a transition geometry between back wall 200 and bottom wall 201 that is curved with a radius of curvature "r". The radius of curvature of the transition bend section can range from 0.05 inches to 2 inches. In other respects, angled rigid plate 195 and angled rigid plate 95 are the same.

[0110] Beyond the bent transition section, the thickness of the bottom wall can be either uniform or tapered such that the thickness decreases from the end of the transition section toward the edge of the bottom wall. Furthermore, beyond the end of the transition section, the bottom surface of the bottom wall in contact with the cementitious slurry is in the shape of a two-dimensional plane with no curvature. The top surface of the bottom wall beyond the end of the transition section can be in the shape of a two-dimensional plane or can have any other curved surface geometry, such as a curved surface that gradually tapers toward the edge of the lower leg. Furthermore, the back wall and bottom wall assembly can be optionally secured together using cross bracing elements, either continuously or intermittently along the length of the assembly. When the assembly is secured continuously, the bracing elements can be a single external add-on piece to the angled elements, or alternatively, can be cast, extruded, or monolithically formed on the angled elements. The continuous bracing elements can have different geometries to provide the desired stiffness to the vibrating assembly. Additionally, the rear wall of the assembly may be a flat two-dimensional planar shape, or alternatively may be formed or curved into a three-dimensional shape to increase the stiffness of the material.

[0111] The angled plate 95 has a surface that contacts the cementitious slurry and another surface, either perpendicular or at an angle to the slurry contacting surface, to which a vibrating motor is mounted or connected.

[0112] The length of the oscillating angled plate 95 (in the machine travel direction "T") on the side that contacts the slurry is typically about 2 inches to 24 inches. A preferred length of the plate on the side that contacts the slurry ranges from about 2 inches to 12 inches. A more preferred length of the plate on the side that contacts the slurry ranges from about 2 inches to 6 inches.

[0113] The width of the oscillating angled plate 95 (transverse to the machine travel direction "T") can range from about 1 ft. to 8 ft. Preferred widths of the metal plate range from about 2 ft. to 6 ft., or about 2 ft. to 5 ft., or about 3 ft. to 4 ft.

[0114] The thickness of the vibrating angled plate 95 on the side in contact with the slurry is typically about 1 / 16 inch to 1 / 4 inch. The vibrating angled plate 95 may gradually taper from the side away from the slurry contact to the edge in contact with the slurry. The preferred thickness of the plate on the side in contact with the slurry is about 1 / 8 inch, tapering from a thickness of 1 / 4 inch on the side away from the slurry contact to 1 / 16 inch on the edge in contact with the slurry.

[0115] The vibrating angled plate 95 is positioned so that the functional edge of the plate remains in contact with the slurry at a depth of 0.05 inches or more into the slurry.

[0116] The vibrating angled plate 95 is vibrated by a vibrating motor 105 having a weight mounted in close proximity to the metal plate so that the vibrations from the motor and the plate remain in phase. The preferred distance of the rotating weight ranges from about 0.50 to 8 inches, about 1 to 7 inches, or about 2 to 6 inches from the metal plate.

[0117] The rotation speed of the eccentric weight is typically about 100 rpm to about 4000 rpm. The vibration motor is mounted for use such that the eccentric weight attached to the rotating shaft rotates in a plane parallel to the metal plate surface that contacts the cement-based slurry.

[0118] Vibration motors 105 are typically electrically driven, but could also be pneumatically or gas-powered mechanical devices. The vibration typically results from the rapid circular motion of a rotating shaft to which an eccentric weight is attached. The eccentricity of the weight controls the amplitude of the vibration, the revolutions per minute controls the frequency of the vibration, and the size of the weight controls the power required by the motor and the strength of the vibration.

[0119] A vibrator mounted on the top surface of the rear wall of the angled rigid plate assembly applies vibrations in a plane parallel to the forming surface of the fiber reinforced cementitious panel. It has been found that vibrations applied in a plane perpendicular to the forming surface of the fiber reinforced cementitious panel do not produce optimal results.

[0120] Additionally, the frequency, amplitude, and mode of vibration of the angled rigid plate assembly is controlled using a vibration controller, which can be either electric or pneumatic. When using an electric vibrator, the range and mode of vibration of the rigid plate assembly is effectively controlled by varying the RPM of an eccentric rotating weight inside the vibrator assembly. The type and amount of vibration applied is tailored based on the rheological properties of the fiber reinforced slurry and the thickness of the slurry layer being used to form the panel.

[0121] Quite surprisingly, it has been found that when the outer edge of the bottom wall of the angled rigid plate assembly is located below the top surface of the panel being formed, a more uniform panel surface profile across the panel width is obtained. Thus, the outer edge of the bottom wall of the angled rigid plate assembly is located about 0.01 inches to 0.25 inches below the top surface of the panel being formed. For example, if the desired panel thickness is 0.75 inches, the outer edge of the bottom wall of the angled rigid plate assembly is located about 0.55 inches to 0.74 inches from the bottom casting surface of the panel, or in other words, about 0.55 inches to 0.74 inches from the moving web along which the panel's casting surface travels. Preferably, the outer edge of the bottom wall of the angled rigid plate assembly is located about 0.02 inches to 0.15 inches below the top surface of the panel being formed. More preferably, the outer edge of the bottom wall of the angled rigid plate assembly is located about 0.03 inches to 0.10 inches below the top surface of the panel being formed. It is an unexpected discovery that setting the rigid plate assembly below the target panel thickness has no effect on reducing the actual thickness of the formed panel.

[0122] H. Apply additional layers To build a fiber reinforced concrete (FRC) panel (structural cementitious panel) of a desired thickness, additional layers are typically added, and for that purpose, a second slurry feeder 78, substantially identical to feeder 44, is provided in operative association with the movable carrier 14 and arranged to deposit an additional layer 80 of slurry 46 onto the existing layer 77.

[0123] An additional chopper 82, substantially identical to choppers 36 and 66, is then provided in operative association with frame 12 to deposit a third layer of fibers 68 provided from a rack (not shown) constructed and disposed relative to frame 12 in a manner similar to rack 31. The fibers 68 are deposited onto the slurry layer 80 and embedded using a second embedding device 86. Similar in construction and arrangement to embedding device 70, the second embedding device 86 is mounted slightly higher relative to the movable carrier web 14 so as not to disturb the first layer 77. In this manner, a second layer 80 of slurry and embedded fibers is created.

[0124] 1 and 6, with each successive layer of settable slurry and fiber, additional slurry feeder stations 78 are provided on the production line 10, followed by a fiber chopper 82 and an embedding device 86. Preferably, four total layers 77, 80, 88, 90 are provided to form an SCP panel 92. For clarity, additional mixers to feed the additional slurry feeder stations 78 may be used, but are not required. They are not shown in the figures.

[0125] An important feature of the present invention is that the panel 92 has multiple layers 77, 80, 88, 90 which, when cured, form an integral fiber reinforced mass. When the presence and placement of the fibers in each layer is controlled and maintained by certain desired parameters as disclosed and described herein, the panel 92 produced by this process is virtually impossible to delaminate.

[0126] I. Forming, smoothing and cutting Four layers of fiber embedded hardenable slurry are deposited as described above. If desired, another thickness control device 93 having an angled plate 95 can be provided as a smoothing device downstream of the final embedding device 86.

[0127] After the layers of the panels 92 are smoothed by the thickness control device 93, they begin to harden. Once the layers are hardened, the respective panels 92 are separated from each other by a cutting device 98, typically a saw or a water jet cutter. Other cutting devices, including movable blades, are deemed suitable for this operation, provided that they can create suitably sharp edges with the current panel configuration. The cutting device 54 is disposed relative to the production line 10 and the frame 12 such that the panels, not shown, are produced having the desired length. Since the speed of the carrier 14 is relatively slow, the cutting device may be mounted to cut perpendicular to the direction of travel of the carrier 14. For faster production speeds, it is known that such cutting devices are mounted on the production line 10 at an angle to the direction of travel of the web. Upon cutting, the separated panels are stacked for further handling, packaging, storage, and / or shipping, as is well known in the art.

[0128] The production line 10 includes sufficient fiber chopping stations 36, 66, 82, slurry feeder stations 44, 78, and embedding devices 70, 86 to produce at least four layers 77, 80, 88, and 90 (FIG. 6). Additional layers may be produced by repetition of the stations as described above in connection with the production line 10.

[0129] During creation of the FRC panel 92, the underside 102 or bottom surface of the panel may be smoother than the top side or top surface 96, even after it is engaged by the forming device 94. In some cases, depending on the application of the panel 92, it may be preferable to have a smooth side and a relatively rough side. However, in other applications, it may be desirable to have a panel where both sides 96, 102 are smooth. The smooth texture is created by the slurry contacting a smooth carrier 14 or carrier web 26.

[0130] Another feature of the present invention is that the resulting FRC panel 92 is constructed such that the fibers 34, 68 are uniformly distributed throughout the panel. This has been found to allow for the production of stronger panels that utilize fewer and more efficient fibers. The volume fraction of fibers relative to the volume of slurry in each layer preferably comprises approximately 1% to 5% by volume of the slurry layers 77, 80, 88, 90, preferably 1.5% to 3% by volume. If desired, the outer layers 77, 90 may have a higher volume fraction than either or both of the inner layers 80, 88.

[0131] In the present invention, which uses multiple separate fiber layers, the panel fiber volume fraction, V f is preferably a percentage of the fiber volume content in each slurry layer, for example, 1-5%. Preferred thickness of the separate slurry layers: ≦0.35 inches. More preferred thickness of the separate slurry layers: ≦0.30 inches. Most preferred thickness of the separate slurry layers: ≦0.25 inches. Preferred fiber strand diameter: ≧30 tex. Most preferred fiber strand diameter: ≧70 tex.

[0132] Suitable layer thicknesses range from about 0.05 inch to 0.35 inch (0.13 to 0.9 cm). For example, to produce a nominal 3 / 4 inch (1.9 cm) thick structural panel, four layers are preferred in the preferred structural panel produced by the present process, with a particularly preferred slurry layer thickness of less than approximately 0.25 inch (0.64 cm).

[0133] If desired, there can be another thickness control device 93 having an angled plate 95 after each embedment roll 48 and / or headbox 78.

[0134] III. The second version of the production line Incorporating a volume fraction of loose fibers distributed throughout the slurry 46 is a critical factor in obtaining a desired panel strength. Therefore, improved efficiency in incorporating such fibers is desirable. It is believed that the system illustrated in Figures 1-6 may, in some cases, require an excessive number of slurry layers to obtain an FRC panel having a sufficient fiber volume fraction.

[0135] Thus, an alternative FRC panel production line or system for producing high performance fiber reinforced FRC panels incorporating a relatively large amount of fiber per slurry layer is illustrated in FIG. 7 and generally designated 130. In many cases, increased fiber levels per panel are obtained using this system. While the systems of FIGS. 1-6 disclose depositing a single separate layer of fiber in each subsequent separate layer of slurry deposited after an initial layer, the production line 130 includes a method for building multiple separate reinforcing fiber layers within each separate slurry layer to obtain a desired panel thickness. Most preferably, the disclosed system embeds at least two separate layers of reinforcing fiber into each separate layer of slurry in a single operation. The separate reinforcing fibers are embedded into the separate layers of slurry using a suitable fiber embedding device.

[0136] More specifically, as seen in FIG. 7, in order to implement multiple layers of fibers 30, 68 of the present system 130 for each layer of the slurry 46, an additional chopping station 142 is provided between the embedding device 136 and the subsequent slurry feeder box 78, so that for each layer of the slurry 46, the fibers 30, 68 are deposited before and after the deposition of the slurry. This improvement has been found to allow for the introduction of significantly more fibers into the slurry, thus increasing the strength of the resulting SCP panel. Preferably, a total of four layers of combined slurry and fibers are provided to form the SCP panel 92, although only three layers are shown.

[0137] IV. The third version of the production line for depositing fiber-containing slurry from a headbox to produce FRC panels from a single layer of slurry The thickness control device of the present invention can also be applied to a process for making fiber reinforced cementitious (FRC) panels, in which, instead of adding the fibers to the slurry on the moving carrier web, the fibers are mixed with the slurry upstream of the moving carrier web to form a fiber-containing cementitious slurry, which is then fed to a headbox and then deposited by the headbox onto the moving carrier web.

[0138] A. Panel Production FIG. 8 illustrates generally a production line, generally designated 310, for producing cementitious panels, for example for producing fiber reinforced concrete (FRC) panels. The production line 310 includes a support frame or forming table 312 having a plurality of legs 313 or other supports. Included on the support frame 312 is a movable carrier 314, such as a seamless rubber-like conveyor belt having a smooth, water-impermeable surface, although porous surfaces such as webs are also envisioned. As is well known in the art, the support frame 312 can be made from at least one table-like segment, which may include the designated legs 313 or other support structure. The support frame 312 also includes a main drive roll 316 at a distal end 318 of the frame, and an idler roll 320 at a proximal end 322 of the frame. At least one belt tracking and / or tensioning device 324 is also typically provided to maintain a desired tension and positioning of the carrier 314 relative to the rolls 316, 320. In this version, cementitious panels are produced continuously as the moveable carrier advances in a direction "T" from the proximal end 322 to the distal end 318.

[0139] In this version, a web 326 of kraft paper, release paper, polymer film, plastic carrier, or nonwoven fibers to support the slurry prior to curing may be provided and placed on the carrier belt 314 to protect the slurry and / or keep it clean. However, it is also envisioned that rather than a continuous web 326, individual sheets of relatively stiff material (not shown), such as, for example, sheets of polymer plastic, may be placed on the carrier 314. These carrier films or sheets may be removed from the produced panels at the end of the line, or they may be incorporated as permanent features within the panels as part of the overall composite design. When these films or sheets are incorporated into the panels as permanent features, they may provide enhanced attributes including improved aesthetics, enhanced tensile and flexural strength, enhanced impact and blast resistance, enhanced environmental durability such as resistance to water and water vapor transmission, freeze-thaw resistance, chloride resistance, and chemical resistance.

[0140] The production line 310 uses a thickness control device 93 having an angled plate 95, the details of which are described above.

[0141] 8 shows the forming table 312, carrier belt 314, and carrier web 326, as well as optional bottom support plate 46A. The production line 310 provides a flat, rigid support bed beneath the angled, rigid plate that is sufficiently adapted and configured to support the fiber-containing slurry and to withstand the downward force imparted by the angled, rigid plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches.

[0142] A flat rigid support bed is provided to counter the downward force of the facer-covered fiber-containing slurry passing under the rigid horizontal upper forming plate 446 and can be, for example, one of the following:

[0143] If sufficiently rigid, the forming table 312; a forming table 312 provided below the carrier belt 314 and further supported by a rigid bottom forming plate 46A; A rigid panel used on the carrier belt 314 under or in place of the carrier web 326; The seamless belt 314 may be supported by rollers that are sufficiently rigid, or There may be a break in the forming table 312 and a rigid lower forming plate 46A is placed at the break directly below the portion of the seamless belt below the upper forming plate 446.

[0144] As mentioned above, it is also envisioned that rather than a continuous carrier web 326, individual sheets of relatively rigid material (not shown), such as, for example, sheets of polymeric plastic, may be placed on the carrier 314. These may also provide a flat, rigid support bed.

[0145] In this version, a continuous reinforcement 344, such as a roving, a web of nonwoven fibers, or a web of reinforcing scrim, such as a fiberglass scrim, may be provided for embedding in the slurry prior to curing and reinforcing the resulting cementitious panel. The continuous roving, web of nonwoven fibers, and / or reinforcing scrim 344 from a roll 342 is fed through a headbox 340 and laid down on the slurry on the carrier 314. However, it is also envisioned that the continuous reinforcement 344 may be used after the headbox 340, or not at all.

[0146] The continuous scrim or roving can be made from different reinforcing fiber materials, including polymeric materials such as fiberglass, polypropylene, polyethylene, polyvinyl alcohol, carbon, graphite, aramid, ceramic, steel, cellulosic or natural fibers such as jute or sisal, or combinations thereof. The roving is an assemblage of continuous reinforcing monofilaments. The scrim is a web of continuous fibers extending in the machine and cross directions. The reinforcement may also be provided as a nonwoven web made of separate reinforcing fibers. If desired, a bottom continuous reinforcement is fed behind the headbox 340 and places it directly on top of the conveying / forming belt. The bottom continuous reinforcement passes under the headbox and the slurry in the headbox 340 is injected directly on top of the continuous reinforcement as it moves forward. For example, the continuous reinforcement can be provided by a web or roll (not shown) upstream of the headbox in addition to providing a web 326 for placing the continuous reinforcement above the web 326.

[0147] It is also contemplated that the cementitious panels produced by the present line 10 may be formed directly on the carrier 314. In this latter situation, at least one belt washing unit 328 is provided. The carrier 314 moves along the support frame 312 by a combination of motors, pulleys, belts or chains that drive a main drive roll 316, as is known in the art. It is contemplated that the speed of the carrier 314 may be varied to suit the product being made.

[0148] The production line 310 includes a continuous slurry mixer 302. The slurry mixer can be a single shaft mixer or a dual shaft mixer. A dry powder feeder 304 feeds the dry components of the cementitious composition, except for the reinforcing fibers, to the slurry mixer 302. A liquid pump 306 feeds an aqueous medium, such as water, along with liquid or water-soluble additives to the slurry mixer 302. The slurry mixer 302 mixes the dry components and the aqueous medium to form a cementitious slurry 331. The cementitious slurry 331 is fed to a first slurry accumulator and positive displacement pump 330, which pumps the slurry to a fiber slurry mixer 332. A fiber feeder 334 feeds fibers 335 to the fiber slurry mixer 332. Thus, in the fiber slurry mixer 332, the fibers and the slurry are mixed to form a fiber slurry mixture 336. The fiber slurry mixture 336 is fed to a second slurry accumulator and positive displacement pump 338 which pumps the fiber slurry mixture 336 to a headbox 340 .

[0149] The headbox 340 deposits the fibrous slurry mixture 346 onto the web 326 of release paper, if present, or continuous reinforcement 344 provided by roving and / or scrim roll 342, if present, traveling on a movable carrier 314. To help level the fibrous slurry mixture 346, a forming vibratory plate 350 may be provided below or slightly downstream from where the headbox 340 deposits the fibrous slurry mixture 346.

[0150] The headbox 340 deposits the fiber slurry mixture uniformly as a layer on a moving surface of a cementitious panel production line having a thickness of 0.125 to 2 inches, preferably 0.25 to 1 inch, typically 0.40 to 0.75 inches, on a moving surface of a panel production line for producing fiber reinforced cement panels. The fiber slurry mixture has a viscosity of less than 45,000 centipoise, preferably less than 30,000 centipoise, more preferably less than 15,000 centipoise, and most preferably less than 10,000 centipoise, as measured using a Brookfield Viscometer, Model DV-II+Pro, with a Spindle HA4 attachment operating at a speed of 20 RPM. Typically, the resulting fiber slurry mixture has a viscosity of at least 1500 centipoise.

[0151] The resulting fiber slurry mixture also has a slump of 4 to 11 inches according to a slump test using a 4 inch high and 2 inch diameter pipe. Fiber slurry mixtures are not typically suitable for extrusion manufacturing processes, which rely on the composition of the slurry mixture having an extremely high viscosity. The slump test used herein utilizes a hollow cylinder about 2 inches in diameter and about 4 inches in length, held vertically with one open end resting on a smooth plastic surface. The cylinder is filled to the top with the cementitious mixture, followed by tapping the top surface to remove excess slurry mixture. The cylinder is then gently lifted vertically, allowing the slurry to exit the bottom and spread over the plastic surface, forming a circular putty. The diameter of the putty is then measured and recorded as the slump of the material. As used herein, compositions with good flow behavior result in a greater slump value.

[0152] The headbox 340 is disposed transverse to the direction of travel "T" of the carrier web 314. The fibrous slurry mixture 346 is deposited within a cavity of the headbox 340 and discharged through a discharge opening onto the moving carrier web 326 (or onto the conveyor belt 314).

[0153] The fiber reinforced cement slurry may be pumped into the headbox 340 through a hose and hose vibrator system or may be dropped directly into the headbox 340 from the fiber slurry mixer 332. A vibrator system is used in either case to agitate the slurry. The thickness of the product formed using the headbox 340 is controlled by the slurry flow rate in the headbox 340, the amount of slurry head rise in the headbox 340, and the gap of the headbox discharge opening for a given line speed. Preferably, the line speed is between 1 and 100 feet per minute, more preferably between 5 and 50 feet per minute. As one skilled in the art will appreciate, other speeds above 100 feet per minute are also contemplated. The size (volume) of the slurry chamber in the headbox 340 is adjusted based on the line speed and the thickness of the product being produced. Preferably, the slurry is deposited into the headbox at a rate of about 0.10 to 25 cubic feet per minute.

[0154] The gap in the discharge opening of the headbox 340 is a lateral opening through which the fibrous slurry mixture discharges from the headbox 40 onto the moving carrier web 326. The fibrous slurry mixture from the headbox is deposited onto the moving carrier web 326 in one step approximating the desired thickness and finish of the final panel 355.

[0155] A headbox thickness control device 93 downstream is provided to control the thickness of the deposited fiber-containing slurry 346. It has the same components and operation as described above for the headbox thickness control device 93 for the multi-layer process and apparatus of FIG.

[0156] In addition to the vibration provided by the angled plate 95 of the headbox thickness control device 93, additional vibration can be added to improve forming, and different forms of continuous reinforcement, such as scrims and rovings, may be added to improve bending strength of the formed product. For example, a vibrating unit 350 may be positioned below the headbox 340 below the conveyor belt 314. The vibrating unit 350 typically vibrates at a speed of 500-3000 cycles per minute, preferably 1000-2000 cycles per minute. The vibrating unit 350 is typically a single mass system of a table, springs, and two motors that directs a force directly to the deposited mat of fiber cement slurry and counteracts it in the other direction. This unit 350 is mounted below the headbox 340 and extends approximately 3-6 inches beyond the headbox 340.

[0157] The slurry 346 hardens as it travels along the movable carrier 326. At the distal end 318 of the support frame 312, a cutter 354 cuts the hardened slurry into FRC panels 355. The FRC panels (boards) 355 are then placed on an unloading and curing rack (not shown) and allowed to harden.

[0158] 8, the production line 310 employs edge forming and leak prevention devices: edge belts, edge rails (used alone or in combination).

[0159] The fiber slurry mixture 336 discharged from the fiber slurry mixer 332 is suitable for making a fiber reinforced cement (FRC) building panel or board 355 .

[0160] The fiber slurry mixture discharged from the fiber slurry mixer 332 has a slump of 4-11 inches, preferably 6-10 inches, as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter, and a viscosity of less than 45,000 centipoise, preferably less than 30,000 centipoise, more preferably less than 15,000 centipoise, and most preferably less than 10,000 centipoise, as measured using a Brookfield Viscometer, Model DV-II+Pro, with a Spindle HA4 attachment operating at a speed of 20 RPM. Typically, the resulting fiber slurry mixture has a viscosity of at least 1500 centipoise. The resulting fiber slurry mixture also has a slump of 4-11 inches, as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter. The resulting fiber slurry mixture is typically not suitable for extrusion manufacturing processes that rely on the composition of the slurry mixture having an extremely high viscosity. The resulting fiber slurry mixture is a uniform fiber slurry mixture having a consistency that allows the fiber slurry mixture to be discharged from the horizontal fiber slurry mixer and suitable for being uniformly deposited as a continuous layer on a moving surface of a panel production line to produce fiber reinforced cement panels, the continuous layer being 0.25 to 2.00 inches thick, preferably 0.25 to 1 inch thick, more preferably 0.4 to 0.8 inches thick, typically 0.5 to 0.75 inches thick.

[0161] The preferred fiber slurry mixture having favorable rheological properties that is processed through this headbox can be beneficially utilized as an effective slurry having a consistency that facilitates further processing and forming of panel products on continuous forming lines operating at high line speeds.

[0162] The preferred fiber slurry mixture for use in the headbox of the single layer process is distinguished from the cementitious mixture used in the extrusion process. The cementitious mixture used in such an extrusion process has a slump of 2 to 3 inches as measured according to the Slump Test using a pipe 4 inches high and 2 inches in diameter, and a viscosity of more than 50,000 centipoise, more typically more than 100,000 centipoise, and most typically more than 200,000 centipoise. The extrusion mixture is also free of the plasticizers and superplasticizers present in the fiber-slurry mixture of the present invention. As mentioned above, plasticizers are generally made from lignosulfonates, which are by-products from the paper industry. Superplasticizers are generally made from sulfonated naphthalene condensates or sulfonated melamine formaldehyde, or based on polycarboxyl ethers.

[0163] B. Slurry mixer for single layer process Any of a variety of continuous or batch mixers may be used as the slurry mixer 302. For example, ICRI Guideline No. 320.5R-2014, Technical Guidelines, Pictorial Atlas of Concrete Repair Equipment, International Concrete Repair Institute, May 2014, incorporated by reference, may be used in the present invention to prepare the cementitious slurry 303. These include horizontal shaft mixers, tumble mortar mixers, rotary drum stationary mixers, pan type mixers, rotating tub rotary paddle mixers, planetary paddle mixers, horizontal shaft mixer and pump combinations, and vertical shaft mixer and pump combinations. The horizontal shaft mixer and pump combinations and the vertical shaft mixer and pump combinations are continuous mixers.

[0164] Continuous slurry mixers can also be used to prepare the slurry in a continuous manner. Commercially available continuous mixers manufactured by PFT GMBH and Co. KG, based in Iphofen, Germany, are suitable. These continuous mixers have the ability to mix and pump the slurry in a continuous manner to the point of application. These mixers have a mixing chamber where all solid dry materials are blended with liquid additives, including water, using a cage agitator that rotates at high speed. In the standard operating mode, the blended cementitious slurry continuously exits the mixing chamber and is pumped forward to the point of application by a progressive cavity pump (rotor stator type pump). Preferred PFT mixer models of the present invention include PFT Mixing Pump G4, PFT Mixing Pump G5, PFT MONOJET 2.13, PFT Mixing Pump T2E, PFT Mixing Pump MS1 and MS2. Additionally, the continuous slurry mixer disclosed in US Pat. No. 7,513,963 B2 to George et al., which is incorporated by reference, may also be used in the present invention.

[0165] For example, the continuous slurry mixer 302 can be a single shaft mixer or a dual shaft horizontal mixer. The term horizontal, when used with mixer, means approximately horizontal. Therefore, a mixer oriented at a plus or minus 20 degree variation from horizontal can still be considered a horizontal mixer.

[0166] C. Horizontal Fiber Slurry Continuous Mixer for Single Layer Process The fiber slurry continuous mixer of the present invention is preferably a continuous horizontal mixer, an example of which is disclosed by U.S. Published Patent Application No. 2018 / 0036912 to Dubey et al., which is incorporated herein by reference.

[0167] The cementitious slurry and fibers are mixed in the mixing chamber of the horizontal fiber slurry mixer for an average mixing residence time of about 5 to about 240 seconds, preferably 10 to 180 seconds, more preferably 10 to 120 seconds, and most preferably 10 to 60 seconds, while the rotating paddles apply shear forces to the fiber slurry mixture and the central rotating shaft rotates at 30 to 450 RPM, more preferably 40 to 300 RPM, and most preferably 50 to 250 RPM during mixing.

[0168] Each horizontal shaft is externally connected to a drive mechanism and drive motor, for example powered by electricity, fuel gas, gasoline, or other hydrocarbons, to effect rotation of the shaft when the mixer is in operation. Typically, an electric motor and drive mechanism will drive the shaft within the mixing chamber.

[0169] D. Inlet port for continuous mixer The size, location, and orientation of the raw material inlet ports (inlet conduits) of the fiber slurry mixer are configured to facilitate the introduction of the raw materials into the fiber slurry mixer and to minimize the possibility of the slurry mixture blocking the ports within the mixer.

[0170] The cementitious slurry from the slurry mixer is preferably conveyed to the fiber slurry mixer using a slurry hose and introduced into the fiber slurry mixer through an inlet port set up to accept the slurry hose.

[0171] The fibers can be introduced into the fiber slurry mixer gravimetrically or volumetrically using various metering devices such as screw feeders or vibratory feeders. The fibers can be conveyed from the fiber feeder to the fiber slurry mixer by various conveying devices. For example, the fibers can be transported using a screw (auger), pneumatic conveying, simple gravity deposition. The separate fibers or chopped fibers can be made from different reinforcing fiber materials including glass fiber, polymeric materials such as polypropylene, polyethylene, polyvinyl alcohol, carbon, graphite, aramid, ceramic, steel, cellulosic or natural fibers such as jute or sisal, or combinations thereof. The length of the fibers is about 2 inches or less, more preferably 1.5 inches or less.

[0172] E. Forming and Cutting for Single Layer Process As described above, once a layer of hardenable slurry with embedded fibers has been deposited, the frame 312 may have a forming device provided to shape the top surface of the hardened slurry fiber mixture 346 as it advances on the belt 314.

[0173] If desired, an additional thickness control device 93 (not shown) may be provided downstream of the thickness control device 93 shown in FIG.

[0174] After one or more thickness control devices 93, the layer of slurry begins to harden and the respective panels 355 are separated from one another by a cutting device 354, typically a water jet cutter or a flying saw. The cutting device 354 is disposed relative to the line 310 and the frame 312 such that the panels are produced having the desired length. When the speed of the carrier web 14 is relatively slow, the cutting device 354 may be mounted to cut perpendicular to the direction of travel of the web 314. For faster production speeds, such cutting devices are known to be mounted on the production line 310 at an angle to the direction of travel of the web. Upon cutting, the separated panels 355 are stacked for further handling, packaging, storage, and / or shipping as is well known in the art.

[0175] Another feature of the present invention is that the resulting cementitious panel, for example, fiber reinforced concrete (FRC) panel 55, is constructed such that the fibers 335 are uniformly distributed throughout the panel. This has been found to allow for the production of stronger panels that utilize fewer and more efficient fibers. The volume fraction of fibers relative to the volume of slurry in each layer preferably comprises approximately 1% to 5% by volume of the fiber slurry mixture 46, preferably 1.5% to 3% by volume.

[0176] Like numbered elements shown in the figures herein are assumed to be the same unless otherwise stated.

[0177] Production line and method having thickness control device with horizontal fixed forming plate - Patents.com V. The fourth version of the production line that deposits separate layers of fibers and slurry to create multi-layer FRC panels FIG. 9 is an elevational view of a fourth version of the FRC panel production line 410 of the present invention, which is the production line of FIG. 1 with an angled plate smoothing device 93 having an angled plate 95 modified to apply a facer 444 and use a fixed horizontal forming plate 446.

[0178] The height of the fixed horizontal forming plate 446 above the movable carrier web is adjustable, for example, by a jack screw or, for example, by a servo-controlled linear actuator.

[0179] In the FRC panel production line 410, the first layer 77 contacts a thickness control device 93 of the present invention for controlling the thickness of the formed, but not yet cured, first layer 77 of fiber reinforced cementitious panel layers, which comprises a fiber-containing cementitious slurry, including a cementitious material and embedded chopped fibers, on the moving carrier web 26. The thickness control device 93 comprises an angled rigid plate 95 and a U-shaped mounting stand 97 for mounting the angled rigid plate 95 on the support frame or forming table 12 for the moving carrier web 26.

[0180] Then, downstream of the thickness control device 93, a facer sheet 444 from a roll 442 is applied onto the surface 77 of the advancing fiber-containing slurry. The facer-covered slurry layer then passes under a fixed horizontal forming plate 446, which is held in place by supports 448.

[0181] Therefore, the present invention provides an FRC panel production line and method for FRC panel production that uses a facer, such as a glass mat, placed across the forming surface and the width of a rigid horizontal upper forming plate to reduce thickness variations during the formation of a fiber reinforced cementitious panel. In the novel invention, a facer, such as a glass mat, is applied to one or both sides of the structural panel during the forming process. A horizontally oriented, rigid horizontal upper forming plate 446 is then used to form the glass / cement slurry of the structural panel to the desired thickness. The position of the entire forming plate 446 is fixed to provide a fixed gap between the lower surface of the forming plate and the moving carrier web below it. It is therefore not a "floating" plate. Due to its horizontal orientation, the entire lower portion of the forming plate 446 contacts the surface of the panel being formed as it passes under the forming plate, not just the downstream end as in the angled rigid plate 95 described above. This process produces panels with less thickness variation and then allows the panel to be formed at a reduced average thickness, e.g., 0.80 inches, without localized smearing below 0.72 inches. Most preferably, when used in conjunction with the top facer 444, the fixed horizontal forming plate 446 allows for the formation of a panel having a desired thickness, such that there is no need for finishing operations such as surface grinding to reduce the panel thickness to the target panel thickness. Therefore, less raw material can be used while producing the same finished product. Additional savings are possible from items such as reduced waste disposal costs, reduced equipment wear, increased production speed, and the like. As previously mentioned, one or two faces may be used in the present invention. Additionally, one or more facers may be temporary, such that the facers are removed before or during finishing operations, or the facers may remain on the finished product.

[0182] The fixed horizontal forming plate 446 is installed at a height where the lower surface of the fixed horizontal forming plate 446 contacts the upper facer 444. Typically, during operation, the fixed horizontal forming plate 446 is installed to position the lower surface of the fixed horizontal forming plate 446 at a height of 0.001 to 0.05 inches, such as 0.01 to 0.03 inches, lower or higher than the target thickness of the FRC panel. For example, for a 0.75 inch FRC panel, the height of the fixed horizontal forming plate 446 may be set at 0.73 inches or 0.77 inches. Most preferably, the fixed horizontal forming plate 446 is installed to position the lower surface of the fixed horizontal forming plate 446 at the same height as the target panel thickness. For example, if the desired panel thickness is 0.75 inches, the height of the fixed horizontal forming plate is set at 0.75 inches.

[0183] 9, the present invention may provide an FRC panel production line and method for FRC panel production that reduces thickness variations during the formation of a fiber reinforced cementitious panel with the use of the angled plate 95 described above and a facer 444, such as a glass mat, placed across the forming surface and width of a fixed horizontal forming plate 446. Such an FRC panel production line and method would contact a fiber-containing slurry with the angled plate 95 described above, then apply a facer 444, such as a glass mat, to the top surface of the structural panel during the forming process, and then run the facer-covered fiber-containing slurry under a rigid horizontal upper forming plate 446.

[0184] To achieve a target panel thickness during the panel forming process using the fixed horizontal forming plate 446 and facer 444, a head of slurry is continuously maintained immediately behind the fixed horizontal forming plate 446. This head of slurry is on and above the continuous, substantially flat ribbon of FRC slurry approaching the fixed horizontal forming plate 446. The presence of this excess slurry behind the fixed horizontal forming plate 446 ensures that the FRC slurry exiting the fixed horizontal forming plate 446 has the proper volume and thickness. Without the slurry head behind the fixed horizontal forming plate 446, any reduction and / or variation in slurry volume occurring behind the fixed horizontal forming plate 446 could result in the formation of a panel having a thickness less than the target panel thickness. The continuous slurry head behind the fixed horizontal forming plate 446 is maintained by adjusting the volumetric output of one or more slurry pumps that feed the slurry to the forming line. Optionally, a separate slurry pump may be provided that feeds slurry directly behind the fixed horizontal forming plate 446. The volume of the slurry head immediately behind the fixed horizontal forming plate 446 is sufficient to counter any normal variations in slurry pump feed rate typically observed with industrial pumps feeding cementitious slurries. The actual volume of slurry head required behind the fixed horizontal forming plate 446 depends on several factors, including the production line speed, the distance between the slurry feeder 44 on the production line and the fixed horizontal forming plate 446, and the ability of the process to control leakage and overflow of slurry behind and around the fixed horizontal forming plate 446. Preferably, the size and volume of the slurry head is uniform across the panel width behind the fixed horizontal forming plate 446. The length of the slurry head extending in the machine direction behind the fixed horizontal forming plate 446 is preferably between 1 inch and 30 inches, more preferably between 2 inches and 24 inches, and most preferably between 3 inches and 18 inches.A smaller length slurry head, such as 4 inches to 12 inches, is preferred because it minimizes static zones within the slurry head where stiffening and hardening of the slurry can occur prematurely and cause problems with uniform formation of the fiber-containing slurry as it passes under the fixed horizontal forming plate 446.

[0185] To facilitate continuous maintenance of the slurry head behind the fixed horizontal forming plate 446, the distance between the last slurry feeder 44 and the fixed horizontal forming plate 446 should be minimized. The distance between the last slurry feeder 44 on the production line and the fixed horizontal forming plate 446 is preferably less than 100 feet, more preferably less than 50 feet, and most preferably less than 25 feet, e.g., less than 10 feet.

[0186] However, when a horizontal forming plate 446 is used in the production line and method of the present invention, the use of the angled plate 95 described above is optional.

[0187] Similarly, when the angled plate 95 described above is used in the production line and method of the present invention, the use of the horizontal forming plate 446 is optional.

[0188] The production line and method may optionally apply a facer, such as a glass mat, to the underside of the structural panel upstream of the slurry headbox during the forming process.

[0189] In a preferred embodiment of the present invention, a side wiper 500, also referred to as a "slurry containment device," is installed on each side of the forming plate 446. The wipers 500 may be attached to the forming plate mounting frame 377 or other structural components of the production line, as will be appreciated by those skilled in the art. The purpose of the side wipers 500 is to dam the slurry at the edges of the panel being formed, thereby preventing excess slurry flow over the edges of the panel being formed that may seep between the upper forming plate 446 and the top surface of the glass mat, creating undesirable appearance and / or thickness variations in the formed panel. The wipers 500 also function to stop the slurry from leaking around the sides of the forming plate 446, thereby preventing the accumulation of hardened slurry that may interfere with continuous operation. A vibrator 502 may be attached to each of the wipers 500. The vibration prevents the slurry from hardening on the wiper 500 itself, and also prevents premature hardening and / or solidification of the slurry behind the forming plate 446.

[0190] In another preferred embodiment of the invention, another agitator 504 or series of vibration means is mounted below the base plate of the forming line just prior to and / or below the upper forming plate 446. One purpose of this agitator 502, 504 is to keep the slurry head dynamic behind the forming plate and prevent the slurry from setting while behind the forming plate.

[0191] Therefore, the present invention provides a fiber reinforced cementitious panel production line, the fiber reinforced cementitious panel production line comprising: A movable carrier web; a support frame for supporting a movable carrier web, the panels being transported on the movable carrier web having a travel direction relative to the support frame; a means for applying a facer, such as a glass mat, onto the fiber-containing cementitious slurry on a moving carrier web, the means for applying the facer being positioned across the width of the forming surface of the moving carrier web; 1. A horizontal thickness control device for controlling the thickness of a formed, but not yet cured, fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry, the fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers, on a moving carrier web, the device comprising: The horizontal thickness control device is a rigid horizontal upper forming plate (e.g., horizontal upper forming plate 446), the rigid horizontal upper forming plate having a flat bottom surface, an upstream end, and a downstream end; a forming plate mounting frame for mounting a rigid horizontal upper forming plate in a horizontal orientation on a support frame for the movable carrier web, the rigid horizontal upper forming plate being mounted to the forming plate mounting frame; a horizontal thickness control device comprising: a flat, rigid support bed underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; a forming plate mounting frame for fixedly but adjustably maintaining the height of the rigid horizontal upper forming plate above the movable carrier web and for maintaining the rigid horizontal upper forming plate parallel to the movable carrier web to fixedly position the flat bottom surface at a height of 0.1 to 2 inches, preferably 0.2 to 1.1 inches, and more preferably 0.5 to 1.1 inches above the movable carrier web; an upstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; a downstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; The entire flat bottom surface is adapted and configured to contact a facer on the fiber-containing slurry as it is transported on the moving carrier web.

[0192] Therefore, the present invention also provides a process for making a fiber reinforced cementitious panel.

[0193] transporting a fiber-containing slurry for the panels on a moving carrier web, the moving carrier web being supported by a support frame, the panels being transported on the moving carrier web having a travel direction relative to the support frame; applying a facer, such as a glass mat, onto the fiber-containing cementitious slurry on the moving carrier web across the width of the forming surface of the moving carrier web to cover the forming surface; passing a forming surface covered with a facer under a horizontal thickness control device for controlling a thickness of a formed but not yet cured fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on a moving carrier web; The horizontal thickness control device is a rigid horizontal upper forming plate (e.g., horizontal upper forming plate 446), the rigid horizontal upper forming plate having a flat bottom surface, an upstream end, and a downstream end; a forming plate mounting frame for mounting a rigid horizontal upper forming plate in a horizontal orientation on a support frame for the movable carrier web, the rigid horizontal upper forming plate being mounted to the forming plate mounting frame; a flat, rigid support bed underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; and controlling a thickness of the formed but uncured fiber reinforced cementitious panel by contacting the formed but uncured fiber reinforced cementitious panel covered with a facer, the fiber containing cementitious slurry, with a bottom surface of a rigid horizontal upper forming plate; the mounting frame is for maintaining a fixed but adjustable height of the angled plate on the movable carrier web to fixedly position the flat bottom surface at a height of 0.1 to 2 inches above the movable carrier web, and for maintaining the rigid horizontal upper forming plate parallel to the movable carrier web; an upstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; a downstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; The entire flat bottom surface contacts a facer on the fiber-containing slurry as it is transported on the moving carrier web.

[0194] 9 shows the forming table 12, seamless belt 14, and carrier web 26 and optional bottom support plates 46A, 46B. The production line 410 provides a flat, rigid support bed beneath the rigid horizontal upper forming plate 446 that is sufficiently adapted and configured to support the fiber-containing slurry and to withstand the downward force imparted by the rigid horizontal upper forming plate 446 with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches.

[0195] A flat rigid support bed is provided to counter the downward force of the facer-covered fiber-containing slurry passing under the rigid horizontal upper forming plate 446 and can be, for example, one of the following:

[0196] If it is sufficiently rigid, the forming table 12; a forming table 12 provided below the carrier belt 14 and further supported by a rigid bottom forming plate 46A; a rigid panel used on the carrier belt 14 under or in place of the carrier web 26; The seamless belt 14 may be supported by rollers that are sufficiently rigid, or There may be a break in the forming table 12 and a rigid lower forming plate 46A is placed at the break directly below the portion of the seamless belt below the upper forming plate 446.

[0197] Figure 9A shows a first close-up perspective view of a portion of the FRC panel production line 410 of Figure 9 for applying facers 444 and using a fixed horizontal upper forming plate 446. For clarity, the mounting frame is not shown.

[0198] 9B shows a second enlarged perspective view of a portion of the FRC panel production line of FIG 9 for applying facers and using fixed forming plates, with the mounting frame not shown for clarity.

[0199] 9C shows a forming plate U-shaped mounting frame 377 for mounting a rigid horizontal upper forming plate 446 in a horizontal orientation on the support frame 12 for the moveable carrier web 26 and facer 444 of the FRC panel production line 410 of FIG. 9. The U-shaped mounting frame 377 has a crossbar 451, and supports 448 with legs 453 and actuators with servo controls 449 extending downwardly from the crossbar 451. The actuators with servo controls 449 are provided to adjust and control the height "H" of the rigid horizontal upper forming plate 446 in a horizontal orientation on the moveable carrier web 26 such that the horizontal forming plate 446 contacts the facer 444 on the upper surface 96.

[0200] The upstream edge 446A (FIG. 9D) of the horizontal forming plate 446 is preferably beveled where it first contacts the facer 444 to avoid damage to the facer 444 that might otherwise occur.

[0201] VI. The fifth version of the production line for depositing fiber-containing slurry from the headbox to produce FRC panels from a single layer of slurry 10 is an elevational view of a fifth version of the FRC panel production line 510 having the angled plate 95 of the present invention modified to apply facer 444 and use a fixed forming plate 446 and, optionally, a bottom support plate 46B. This is the production line 310 of FIG. 8 modified to apply facer 444 from a roll 442 and use a fixed forming plate 446 supported by supports 448. Optionally, bottom support plates 46A, 46B may also be used. Like numbered elements in FIG. 10 and other figures herein are the same elements and operate similarly unless otherwise noted.

[0202] If desired, additional fixed forming plates 446 (not shown) may be provided and applied to the facer 444 upstream or downstream of the fixed forming plate 446 shown in FIG.

[0203] Wrapping fiber-reinforced concrete (FRC) panels with nonwoven fabric layers The invention also encompasses the production of boards wrapped with nonwoven fibrous mats, typically nonwoven polymeric fibrous mats such as polypropylene mats, or substantially inorganic nonwoven fibrous mats such as fiberglass mats, on a panel production line. The inorganic nonwoven fibrous mats may optionally be coated with various coating materials that impart handling characteristics to the continuous web and improve physical and chemical durability. The nonwoven fibrous mats are preferably applied to both major surfaces of the panel, but may optionally be applied to only one of the major surfaces of the panel.

[0204] Figure 10A shows a cementitious panel production line 610 for use with the fiber slurry mixing device of the present invention. This is the production line 510 of Figure 10 modified to apply a nonwoven fiber mat 444A below the fiber slurry mixture and a nonwoven fiber mat 444 above the fiber slurry mixture 346 to encase the produced board 355. (However, this modification could also be used to modify any version of the present invention, for example, a version of the present invention to make a multi-layer FRC panel.) In Figure 10A, like reference numbers from Figure 10 or other figures herein are used to represent like elements that operate in a similar manner.

[0205] Both the angled plate 95 and horizontal forming plate 446 described above are shown for use in the cementitious panel production line 610. Optionally, bottom support plates 46A, 46B may also be used. In this and other production lines and methods of the present invention that use the horizontal forming plate 446, the use of the angled plate 95 described above is optional.

[0206] Similarly, when the angled plate 95 described above is used in the production line and method of the present invention, the use of the horizontal forming plate 446 is optional.

[0207] FIG. 10A shows a first continuous mat of nonwoven (preferably fiberglass or multi-layer polyolefin) fibers 444A from a feed roller 442A passing under roller 442B onto the surface of the moving belt 314. The fiber reinforced cementitious slurry mixture 346 produced in the fiber slurry mixer is then deposited onto the first mat of nonwoven fibers 444A using a forming headbox 340. The mat of nonwoven fibers 444A on the moving surface of the panel production line 610 extends from the right and left sides of the hardened fiber slurry mixture 346 for the board 355. The mat 444A can optionally be wider than the width of the subsequent formed panel, with edges 444B and 444C folded into an upright position before passing under the headbox 340.

[0208] The surface of the deposited fiber-containing slurry 346 is then smoothed by passing the deposited fiber-containing slurry 346 under the angled plate 95 and contacting the surface of the deposited fiber-containing slurry 346 with the downstream end of the angled plate 95 as described above.

[0209] If the mat 444A is wider than the subsequently formed panel, the optional folding unit 230 optionally not only wraps around the right and left sides of the hardened fiber slurry mixture 346 for the board 355, but also optionally folds the upright edges 444B, 444C (see FIG. 10B) of the mat 444A again to provide an overlapping area with the mat 444. Thus, the mat 444A can be wrapped around the hardened fiber slurry mixture 346 of the board 355 to wrap the right and left edges 444B, 444C (FIG. 10B) of the mat 444A when the board 355 is not fully hardened, and optionally provide an overlapping area with the mat 444.

[0210] The present invention then feeds a top mat (web) 444 of nonwoven fibrous material from a supply roll 442 and then under an optional application roll 442C onto the top surface of the fibrous slurry mixture. Optionally, adhesive may be applied to the folded edges of the top mat (web) 444 and / or the mats 444A where they overlap. The fibrous slurry mixture 346 covered with the nonwoven fibrous mat 444 then passes under a horizontal forming plate 446 to smooth the surface of the panel 355.

[0211] Therefore, the method comprises: applying a first web 444A of nonwoven fibers onto a moving surface of a panel production line, the first web 444A being sufficiently impermeable to prevent penetration of the fiber slurry mixture on the panel production line, the first web 444A being wider than the cement board 355 being made, and forming a continuous trough by bending an outer portion of the first web 444A upright; continuously depositing a fibrous slurry mixture 346 from the headbox 340 onto the first web 444A and laterally distributing the fibrous slurry mixture 346 to fill the trough to a substantially uniform depth; passing the fiber slurry mixture 346 under the angled plate 95 and contacting a downstream end of the angled plate 95 to smooth a surface of the fiber slurry mixture 346; Then, at the folding station 230, the edges of the lower facer 444A are folded to provide an overlap area with the upper facer 444; applying a second web of nonwoven fibers 444 on top of the set fiber slurry mixture 346 on a panel production line 610; Then, contacting a second web 444 of nonwoven fibers on the top surface of the set fiber slurry mixture 346 with a stationary forming plate 446; The stiffening panel 355 may then be cut with a cutting device 354 to form the FRC panel 355.

[0212] The folding unit 230 may optionally be positioned downstream of the fixed upper forming plate 446. In this case, the upstanding edges 444B and 444C may not pass under the upper forming plate 446 but may instead abut its edges. The folding unit 230 then further folds the upstanding edges 444B and 444C, so that an overlap is formed with those portions of the mat 444A positioned on the mat 444. The folding unit 230 may be any suitable folding unit. For example, US 5,221,386 to Ensminger et al., incorporated herein by reference, describes an apparatus for encasing the bare surfaces of a hardened cement panel with a woven mesh of reinforcing fibers that underlie (in other words, are embedded in) the top, bottom, and longitudinal edge surfaces. The Ensminger et al. apparatus can be adapted for folding unit 230 by replacing its cement and woven mesh with hardened fiber slurry mixture 346 and nonwoven fiber mat 444, 444A (not embedded) for board 355. The Ensminger et al. apparatus includes a pair of edger rails that slidably ride on the conveyor belt and define a path for the cement board being created on the conveyor belt, and a means for folding and pressing the outer edges of the bottom mesh comprising a first pair of curved spatulas mounted on the conveyor belt on a crossbar transverse to the direction of travel of the moving fiber slurry mixture.

[0213] Therefore, to achieve the folding, the present invention may employ a first pair of curved spatulas (not shown) mounted on top of the fiber slurry mixture 346. For example, the spatulas may be mounted on a crossbar (not shown, but as disclosed in Ensminger et al., US 5,221,386) transverse to the direction of travel of the moving fiber slurry mixture. As the trough of the fiber slurry mixture 346 approaches the first pair of curved spatulas, the edges of the first mat 444A and the walls of the trough they form contact the spatulas and are forced under them, initiating the folding of the successively approaching mat 444A.

[0214] Preferably, the mats are not substantially embedded within the cementitious core. Preferably, less than about 50% of the thickness of each mat is embedded within the cementitious core, more preferably less than about 30% is embedded within the cementitious core, even more preferably less than about 15% and even more preferably less than about 5% is embedded within the cementitious core.

[0215] In this production line 210, an optional web 326 of release paper, polymer film or plastic carrier to support the slurry prior to curing may be provided and placed on the carrier 314 to protect the slurry and / or keep it clean. It is also envisioned that rather than a continuous web 326, individual sheets of relatively stiff material (not shown), such as, for example, sheets of polymer plastic, may be placed on the carrier 314. These carrier films or sheets may be removed from the produced panels at the end of the line, or they may be incorporated as permanent features of the panels as part of the overall composite design. When these films or sheets are incorporated into the panels as permanent features, they may provide enhanced attributes including improved aesthetics, enhanced tensile and flexural strength, enhanced impact and blast resistance, enhanced environmental durability such as resistance to water and water vapor transmission, freeze-thaw resistance, chloride resistance, and chemical resistance.

[0216] The nonwoven fibrous mats 444, 444A may optionally be used in conjunction with the continuous web 326 (e.g., the continuous web 326 may be a release paper that prevents any slurry that has permeated the nonwoven fibrous mat 444A from reaching the forming belt). When using the web 326 as a permanent feature of the panel and using a relatively impermeable nonwoven fibrous mat 444, 444A, the web 326 may be attached to the nonwoven fibrous mat 444, 444A with an adhesive (e.g., the web 326 may comprise a pressure sensitive adhesive). However, the web 326 or individual sheets of relatively stiff material (not shown) are optional and are preferably not used in this production line 610 of FIG. 10A (further 42) when a relatively impermeable mat 444A, 444 is used. Alternatively, and preferably, the continuous web 326 is a relatively impermeable nonwoven fibrous mat, in which case the relatively impermeable nonwoven fibrous mat 444A is not used.

[0217] 10B is a schematic perspective view of the FRC panel 355 of FIG. 10A wrapped with a nonwoven fiber mat made according to production line 610. The nonwoven fiber mat covering includes a core of hardened fiber slurry mixture 346, a front mat 444, and a rear mat 444A having right and left edges that wrap around the right and left sides of the panel 355 around the front of the panel. The mats 444 and 444A are preferably the same material, but can optionally be made of different materials depending on the product application requirements. In some embodiments, a nonwoven fiber mat may be used on only one of the major faces of the panel.

[0218] In the production line 610, the upright portions of the first facer (mat) 444A are folded before application of the top web to create a panel as in FIG. 10B.

[0219] In an alternative method (not shown), the folding unit 230 is moved from upstream of the forming plate 446 to downstream of the horizontal forming plate 446. The fiber slurry mixture 346 covered with the nonwoven fiber facer mat 444 passes under the horizontal forming plate 446 to smooth the surface of the panel upstream of the folding unit 230. The folding unit 230 then folds the edge of the lower facer 444A over the edge of the upper facer 444 to encase the FRC panel 355. In particular, the right and left edges 444B, 444C are encased and, optionally, glued where they overlap the upper facer 444. The encased set fiber slurry mixture 346 for the board 355 is then processed as described above for the production line 310 of FIG. 8.

[0220] Materials and constructions for fully unembedded nonwoven fiber mats - Patents.com These nonwoven fiber mats of the present invention, designed to not be completely embedded in the fiber slurry mixture, such as mats 444, 444A in FIG. 10A, comprise any suitable type of polymer fiber, glass fiber, or combinations thereof. Preferably, the majority of the fibers in the nonwoven fiber mat are glass or polymer fibers. Non-limiting examples of suitable fibers include glass fibers, polyamide fibers, polyaramid fibers, polypropylene fibers, polyester fibers (e.g., polyethylene terephthalate (PET)), polyvinyl alcohol (PVOH), polyvinyl acetate (PVAc), cellulosic fibers (e.g., cotton, rayon, etc.), and combinations thereof. Additionally, the fibers of the mats may be hydrophobic or hydrophilic, coated or uncoated.

[0221] These nonwoven fiber mats are not permeable to the fiber slurry mixture or are at most slightly permeable to the fiber slurry mixture. In particular, the nonwoven fiber mats provide sufficient impermeability to prevent the fiber slurry mixture of the present invention from penetrating even when the fiber slurry mixture of the present invention is vibrating and / or forming a plate on the production line. The fiber slurry mixture of the present invention may undergo shear thinning when vibrating or expanding on the panel production line. This makes the selection of the appropriate nonwoven sheet to prevent penetration important. When the mats are nonwoven fiberglass mats, they are not fully embedded in the fiber reinforced cementitious slurry material because they are coated nonwoven fiberglass mats. The embodiments of the present invention having mats that are not embedded do not use woven glass mats because woven glass mats are not stiff enough to prevent the penetration of the slurry through them. The present invention contemplates the use of upper and / or lower meshes and scrims, e.g., woven glass mats, when embedding is desired.

[0222] In an alternative embodiment, the nonwoven fibrous mat is preferably made from polyolefins, preferably polypropylene and / or polyethylene.

[0223] The nonwoven fiber mats can each be a single layer. For example, the preferred coated fiberglass mat is a single layer. However, the polymer mat is preferably made of two or more layers. For example, FIG. 10C shows a side cross-sectional view of a polymer fiber mat having a laminated composite structure of one spunbonded layer of fiber and a relatively impermeable meltblown layer of fiber. More preferably, the mat 444 is a polyolefin mat having two spunbonded layers 446A, 446C of fiber and a meltblown layer 446B of fiber sandwiched between the spunbonded layers. The meltblown layer provides sufficient impermeability to prevent the fiber slurry mixture of the present invention from penetrating even when the fiber slurry mixture of the present invention is vibrating and / or forming a plate on a production line.

[0224] The fibers used in the nonwoven glass mat should be at least 0.25 inches or more in length, more preferably at least 0.5 inches or 3 / 4 inches in length, and most preferably at least about 1 inch in length, although mixtures of fibers of different lengths and / or fiber diameters can be used as known. The fibers are preferably coated with a silane-containing sizing composition as is well known in the art. The preferred continuous glass fibers for the fibrous web are at least one member selected from the group consisting of E, C, T type and sodium borosilicate glasses, and mixtures thereof. As known in the glass art, C glass typically has a soda-lime borosilicate composition that improves chemical stability in corrosive environments, while T glass often has a magnesium aluminosilicate composition and is filamentary and has particularly high tensile strength. The mat of the present invention is preferably composed of E glass, also known as electric glass, typically having a calcium aluminoborosilicate composition and a maximum alkali content of 2.0%. E glass fibers are commonly used to reinforce a variety of articles. The chopped fibers of the major portion can have a variety of lengths, but more commonly are substantially similar in length. E-glass fibers have sufficient strength and other mechanical properties to produce acceptable mats, and are widely available at relatively low cost. Most preferred is E-glass, having an average fiber diameter of about 11 + / - 1.5 μm, and lengths in the range of about 6 to 12 mm.

[0225] Nonwoven fiber mats generally include fibers bonded together by binders, solvent treatment, or heat. The binder can be any binder commonly used in the mat industry. Suitable binders include, but are not limited to, urea formaldehyde, melamine formaldehyde, melamine formaldehyde stearate, polyester, acrylics, polyvinyl acetate, polyvinyl acetate or acrylic, urea formaldehyde or melamine formaldehyde modified or blended with styrene acrylic polymers, and combinations thereof. Typical polymer fibers are either nylon, polyester, polyethylene, or polypropylene. Any suitable amount of binder can be used. However, meltblown nonwoven fiber mats do not require a binder.

[0226] Typically, the fiber mat can have any suitable weight effective to prevent bleed-through during manufacturing. Typically, for glass mats, the basis weight is about 88 g / m 2 or more (for example, about 88 to 147 g / m 2 ) equivalent to approximately 18lbs / 1000ft 2 or more (e.g., about 18-30 lbs / 1000 ft 2 In one embodiment, the fiber mat, particularly the glass fiber mat, has a density of about 98 g / m 2 or more (for example, about 98 to 127 g / m 2 (equivalent to approximately 20lbs / 1000ft 2 or more (e.g., about 20-26 lbs / 1000 ft 2 , or about 23-26lbs / 1000ft 2 ) basis weight.

[0227] Typically, for polymer mats, the basis weight is about 39 g / m 2 or more (for example, about 39 to 147 g / m 2 ) equivalent to approximately 8lbs / 1000ft 2 or more (e.g., about 8-30 lbs / 1000 ft 2 ), preferably about 73 g / m 2 or more (for example, about 73 to 98 g / m 2(equivalent to approximately 15lbs / 1000ft 2 or more (e.g., about 15-20 lbs / 1000 ft 2 ) basis weight.

[0228] The mats are preferably each made of a single layer of nonwoven glass fiber. Alternatively, they are preferably each made of a nonwoven polymer (preferably polyolefin) mat having a multi-layer laminate structure. Figure 44 is a schematic diagram of a nonwoven polymer front mat 44 having a preferred multi-layer structure of three layers 46A, 46B, 46C. This polymer mat 44 has two spunbonded layers 46A, 46C of fibers and a meltblown layer 46B of fibers sandwiched between the spunbonded layers 46A, 46C. The meltblown layer provides sufficient impermeability to prevent the fiber slurry mixture of the present invention from penetrating even when it is vibrating and / or forming a plate on a production line.

[0229] The nonwoven fiber mat applied to the panel surface provides a smooth surface to the finished product and also aids in the lamination of the fiber reinforced concrete panels during manufacture. There is no need to stack the panels separately on racks during curing, and if the panels are sufficiently cured, the wrapped panels can be directly stacked on top of each other during curing. Casting the edges of the fiber reinforced concrete panels onto the nonwoven fiber mat facilitates edge forming and cleaning. A cast panel with the back, sides, and front made of a sufficiently impermeable mat has the advantages of a better surface, easier cleaning, and simplified lamination of the boards (during manufacture). This process also produces FRC panels that require little or no surface finishing. The use of a nonwoven glass mat has the advantage of better adhesion than a nonwoven polymer mat. The use of a nonwoven polymer mat has the advantage of better alkali resistance than a nonwoven glass mat. EXAMPLES

[0230] Example 1 - Data from plant trials and pilot plant trials Production trial 1 uses a Type 1 electric vibration motor with a controller with various vibration settings and gap between the metal plate and the forming surface. Vibration plate mounting angle at the forming surface = 20 degrees (approximately). The Type 1 vibrator refers to a DC power supply and regulated motor to produce the desired vibration characteristics. The Type 1 vibrator assembly includes a lithium iron phosphate battery pack (36V and 10 amp-hour capacity), a control box, a throttle assembly to adjust the vibration intensity, and a DC motor with a gearbox and rotating eccentric weight. Table 1 shows the experimental conditions.

[0231] The vibration plate and motor were installed on the production line using the mounting frame as described above. The gap between the forming surface and the vibration plate was set and measured using a gauge block, and the vibration settings were adjusted with the throttle assembly for each trial condition. After stable production conditions were obtained, the vibration plate was engaged at the desired experimental settings. Sample panels produced with the vibration plate invention were marked and collected for curing. Similarly, samples in other experimental conditions such as those in Table 1 were also marked and collected for curing. The normal vibration plate remained engaged or disengaged for each experimental condition, and the sample panels were collected accordingly. Upon curing, the formed sample panels were cut into four pieces A, B, C, and D as seen diagrammatically in FIG. 11, where piece A was formed before piece D, and thickness was measured at 1 inch intervals around all edges of the pieces. FIG. 11 shows the dimensions in inches. FIG. 11 is a cut diagram for the sample panels for the experimental conditions. Thickness measurements were taken along the edges of these pieces and integrated to estimate the standard deviation in the machine and cross-machine directions. Thickness data measurements taken along the forming direction (along the length of the panel on the longer edge) were used to estimate the standard deviation of thickness in the machine direction. Thickness data measurements taken along the direction perpendicular to the forming direction (along the width of the panel on the shorter edge) were used to estimate the standard deviation of thickness in the cross-machine direction. Similarly, the difference between the maximum and minimum thickness of the panel in each direction was estimated. [Table 1]

[0232] 11A shows the standard deviation in inches and the difference in maximum and minimum thickness in inches of formed panels for different experimental conditions in Table 1 for samples measured in the cross-machine direction with and without the angled plate thickness control device of the present invention. Control #1 and Control #2 are experimental conditions without the angled plate thickness control device of the present invention.

[0233] FIG. 12 shows the cross-sectional thickness profile in inches of the cementitious panel formed from FIG. 11 in the cross-machine direction without the use of the angled plate thickness control device of the present invention.

[0234] FIG. 13 shows the cross-sectional thickness profile in inches of the cementitious panel formed from FIG. 11 in the cross-machine direction using the angled plate thickness control device of the present invention.

[0235] Example 2 - Data from plant and pilot plant trials testing the angled plate thickness control device Production trial 2 uses a Type 2 electric vibration motor with a controller with various vibration settings and gap between the metal plate and the forming surface. The vibrating angled plate mounting angle at the forming surface of the fiber-containing slurry was 20 degrees (approximately). The Type 2 vibrator refers to an AC power source and an adjustable motor to produce the desired vibration characteristics. The Type 2 vibrator assembly included an AC powered electrical control box (110-120V and 1.3 amps) with a rotating knob / dial to adjust the vibration intensity, and a motor with a gearbox and rotating eccentric weight. Table 2 shows the experimental conditions.

[0236] The vibration plate and motor were installed on the production line using a mounting frame as described above. The gap between the forming surface and the vibration plate was set and measured using a gauge block, and the vibration settings were adjusted with a rotary knob / dial on the electrical control box for each trial condition. After stable production conditions were obtained, the vibration plate was engaged at the desired experimental settings. The sample panels produced with the vibration plate invention were marked and collected for curing. Similarly, samples in other experimental conditions as in Table 2 were also marked and collected for curing. The normal vibration plate remained engaged or disengaged for each experimental condition, and the sample panels were collected accordingly. Upon curing, the formed sample panels were cut into eight pieces A1, A2, B1, B2, C1, C2, D1, and D2 as in FIG. 11B, where pieces A1 and A2 were formed before pieces D1 and D2, and the thickness was measured at 1 inch intervals across all edges of the pieces. FIG. 11B is a cut diagram for the sample panels for the experimental conditions. Thickness measurements were taken along the edges of these pieces and integrated to estimate the standard deviation in the machine and cross-machine directions. Thickness data measurements taken along the forming direction (along the length of the panel on the longer edge) were used to estimate the standard deviation of thickness in the machine direction. Thickness data measurements taken along the direction perpendicular to the forming direction (along the width of the panel on the shorter edge) were used to estimate the standard deviation of thickness in the cross-machine direction. Similarly, the difference between the maximum and minimum thickness of the panel in each direction was estimated. [Table 2]

[0237] FIG. 14 shows the standard deviation in inches and the difference in maximum and minimum thickness of the formed panel for different experimental conditions in Table 2 for samples measured in the cross-machine direction with and without the angled plate thickness control device of the present invention. Control #1 and Control #2 are experimental conditions without the angled plate thickness control device of the present invention. FIG. 15 shows the standard deviation and the difference in inches and the difference in maximum and minimum thickness of the formed panel for different experimental conditions in Table 2 for samples measured in the machine direction with and without the angled plate thickness control device of the present invention. Control #1 and Control #2 are experimental conditions without the angled plate thickness control device of the present invention. FIG. 14 has information on panel thickness measurements across the cross-machine direction (XMD) and FIG. 15 has information on panel thickness measurements along the machine direction (MD). The objective is to demonstrate the reduction of variation in both XMD and MD.

[0238] The units in Figures 11-17 are inches. The panels tested were 4 feet by 8 feet. Therefore, the cross-machine measurements spanned 48 inches and the machine-direction measurements spanned 96 inches.

[0239] FIG. 16 (Board #12 cross-machine direction) shows the cross-sectional thickness profile in inches of a cementitious panel formed without the use of the angled plate thickness control device of the present invention.

[0240] FIG. 17 (Board #7 cross-machine direction) shows the cross-sectional thickness profile in inches of a cementitious panel formed using the angled plate thickness control device of the present invention.

[0241] Tables 3A and 3B provide a comparison of formed thickness variation in inches for cementitious panels formed with and without the angled plate thickness control device of the present invention. [Table 3] [Table 4]

[0242] Example 3 - Data when using a thickness control device with a fixed horizontal forming plate and facer applied The following Table 4 shows thickness data in inches when applying the facer at a fixed height above the moving carrier web on an FRC monolayer panel production line and using a horizontal forming plate. The data is based on pilot scale production using a pilot line.

[0243] The board composition was consistent with that described above for the single-ply process. The boards were made using a gypsum cement binder composition. The cementitious binder included a composite mix of calcium sulfate alpha hemihydrate, Portland cement, silica fume, and hydrated lime added in the following ratios of 62:25:12:1, respectively. Expanded perlite was used as a lightweight filler. The perlite particles were chemically coated with a silicon-based hydrophobic chemical coating to reduce the water absorption rate of the particles. The weight ratio of perlite to cementitious binder was 0.09. Water and chemical processing aids were added in sufficient amounts to obtain an aqueous mixture of the required consistency for the process. Alkaline resistant glass fiber was used as the structural reinforcement within the panels.

[0244] The pilot-scale production line includes equipment for mixing the cement mix, water, and glass fiber, and equipment for delivering the mixture to the forming area on a belt conveyor, as shown in FIG. 10. Thus, a ribbon of board is formed on the conveyor. As described in the present invention, a facer and an upper forming plate were used to control the thickness of the formed board. In this example, the experimental horizontal forming plate was constructed of stiffened plywood, and height adjustment was achieved using jack screws. The experimental mounting frame was constructed of extruded aluminum. Although the experimental horizontal forming plate assembly was not industrially robust, the formed board thickness results showed a surprising improvement over the normal production results. [Table 5]

[0245] Example 4 - Data from a plant trial testing a thickness control device with a fixed horizontal forming plate The data was generated from trials within a large scale manufacturing plant.

[0246] In the following Table 5, the samples designated with an "R" are control samples made in the normal manner on an FRC panel production line without the use of a thickness control device with a fixed horizontal forming plate. The samples beginning with a "T" are trial samples made on the production line using a thickness control device with a fixed horizontal forming plate of the present invention. Each "R" or "T" sample is a 4" by 8" panel.

[0247] The board composition was consistent with that described above for the single-ply process. The boards were made using a gypsum cement binder composition. The cementitious binder included a composite mix of calcium sulfate alpha hemihydrate, Portland cement, silica fume, and hydrated lime added in the following ratios of 62:25:12:1, respectively. Expanded perlite was used as a lightweight filler. The perlite particles were chemically coated with a silicon-based hydrophobic chemical coating to reduce the water absorption rate of the particles. The weight ratio of perlite to cementitious binder was 0.09. Water and chemical processing aids were added in sufficient amounts to obtain an aqueous mixture of the required consistency for the process. Alkaline resistant glass fiber was used as the structural reinforcement within the panels.

[0248] The experimental forming plate system described in Example 3 was removed from the pilot scale line and installed on a production line, similar to Figure 8. Again, the formed board thickness results showed a surprising improvement over the normal production results. [Table 6]

[0249] Standard deviation and range are from approximately 500 data points per 4 ft. x 8 ft. panel. A sampling pattern was developed by marking sample lines on a 2 ft. x 2 ft. grid, with individual thickness measurements located every inch along the grid lines.

[0250] The data is also presented graphically in Figures 18-29, which show cross-sectional profiles measured in the cross-machine direction and in the machine direction in a multi-layer FRC panel production process. In these figures, the solid lines at the top and bottom, without markings for data points, are + / - 0.03 inches from the actual average thickness of each FRC panel. The data lines in Figures 18-29 are individual thickness measurements per inch in the machine direction (8 feet) and cross-machine direction (4 feet). Thus, in Figures 18-29, the Y-axis is thickness in inches. In the figures for the cross-sectional profiles measured in the cross-machine direction, the X-axis is each of the 48 inches across the cross-machine direction of the 4 feet of the FRC panel. In the figures for the cross-sectional profiles measured in the machine direction, the X-axis is each of the 96 inches across the machine direction of the 8 feet of the FRC panel.

[0251] FIG. 18 (#R3 cross-machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #R3 herein measured in the cross-machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate.

[0252] FIG. 19 (#R3 machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #R3 herein measured in the machine direction of the control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate.

[0253] FIG. 20 (#R4 cross-machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #R4 herein measured in the cross-machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate.

[0254] FIG. 21 (#R4 machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #R4 herein measured in the machine direction of the control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate.

[0255] FIG. 22 (#2R1 cross-machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #2R1 herein measured in the cross-machine direction of a control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate.

[0256] FIG. 23 (#2R1 machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #2R1 herein measured in the machine direction of the control specimen made on an FRC panel production line in the conventional manner without a thickness control device with a fixed horizontal forming plate.

[0257] FIG. 24 (#T1 cross-machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #T1 herein measured in the cross-machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention.

[0258] FIG. 25 (#T1 machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #T1 herein measured in the machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention.

[0259] FIG. 26 (#T2 cross-machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #T2 herein measured in the cross-machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention.

[0260] FIG. 27 (#T2 machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #T2 herein measured in the machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention.

[0261] FIG. 28 (#T4 cross-machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #T4 herein measured in the cross-machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention.

[0262] FIG. 29 (#T4 machine direction) shows the cross-sectional profile of the formed cementitious panel for Example #T4 herein measured in the machine direction of a trial specimen made on a production line having a thickness control device with a fixed horizontal forming plate of the present invention.

[0263] The data in this example demonstrated the effectiveness of the fixed horizontal forming plate of the present invention in reducing thickness variation. The data in this example proved the concept of FRC panels produced with a dramatic reduction in thickness variation for making FRC panels formed with multiple layers of cement slurry and fiberglass in addition to panels formed with only one layer of premixed cement slurry and fiberglass. This reduction allows for the avoidance of individual smears that would result in the panel being rejected as being out of specification while reducing the average thickness of the formed panel.

[0264] Example 5 - Achieving target panel thickness on a panel forming line by using a thickness control device with facer fabric and fixed horizontal forming plate Production trials with a fixed forming plate were conducted using a multi-layer process in a large-scale manufacturing plant. A glass mat facer was used in conjunction with the fixed forming plate. Multi-layer panels were made utilizing four separate slurry layers and seven separate fiber layers. The target panel thickness was 0.77 inches with a tolerance of + / - 0.03 inches. The fixed forming plate was the same as described in Example 4. The forming plate was adjusted so that the gap between the bottom surface of the forming plate and the forming surface was approximately 0.77 inches.

[0265] The boards were made using a gypsum cement binder composition. The cement binder included a composite mix of calcium sulfate alpha hemihydrate, Portland cement, silica fume, and hydrated lime added in the following ratios of 62:25:12:1, respectively. Expanded perlite was used as a lightweight filler. The perlite particles were chemically coated with a silicon-based hydrophobic chemical coating to reduce the water absorption rate of the particles. The weight ratio of perlite to cement binder was 0.09. Water and chemical processing aids were added in sufficient amounts to obtain an aqueous mixture of effective consistency required for the process. Alkali-resistant glass fiber was used as structural reinforcement in the panels.

[0266] Five panels measuring 48 inches by 96 inches were selected for thickness measurements. Thickness measurements were taken in the machine direction (i.e., along the 96 inch dimension) as well as the cross-machine direction (i.e., across the 48 inch dimension). Thickness measurements were taken at 4 inch intervals, i.e., 24 measurements were taken in the machine direction and 12 measurements were taken in the cross-machine direction. Table 6 shows the average thickness measured, as well as the standard deviation measured. It can be observed that the average measured thickness of the five panels was 0.783 inches in the machine direction as well as 0.783 inches in the cross-machine direction. It can also be observed that the measured panel thicknesses were within the target thickness specification of 0.77 + / - 0.03 inches. [Table 7]

[0267] Example 6 - Improved Weather Resistance and Exterior Durability of Panels Using Glass Mat Facers Surprisingly, it has been found that the application of a facer fabric material on the panel surface helps to significantly improve the durability of the panel when exposed to weathering in an exterior environment. The panels from Example 4 with glass mat facer were exposed to weathering in an exterior weathering exposure site located in Illinois, USA, as shown in FIG. 30. The panels (24 inch by 24 inch size specimens) were exposed for about 9 months, undergoing one winter, one spring, and one summer. At the end of the summer, observations were made to evaluate the physical properties and durability of the panels. FIG. 31a shows a photograph of an FRC panel without a facer after 9 months of exterior exposure. FIG. 31b shows a photograph of an FRC panel with a glass mat facer only on the top surface after 9 months of exterior exposure. The panel with the glass mat was found to be in very good condition, with the glass mat firmly bonded to the base panel. The back surface and cut edges were in very good condition, with no signs of erosion or damage to the material observed. This surprising physical behavior is comparatively superior to FRC panels without the glass mat, where surface erosion of the panel (slight pitting and surface wear) can be observed upon prolonged exposure to exterior weathering.

[0268] Provisions of the present invention The following sections disclose aspects of the present invention.

[0269] Clause 1. A production line for fiber reinforced cementitious panels, comprising: A movable carrier web; a support frame for supporting a movable carrier web, the panels being transported on the movable carrier web having a travel direction relative to the support frame; 1. A thickness control device for controlling a thickness of a formed, but not yet cured, fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on a moving carrier web, the thickness control device comprising: An angled rigid plate; a mounting frame for mounting an angled rigid plate on a support frame for the moving carrier web; a flat, rigid support bed underlying the angled, rigid plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing slurry and to withstand a downward force imparted by the angled, rigid plate, preferably with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; the angled rigid plate has a laterally upstream rear wall, a laterally downstream bottom wall extending downstream from a lower end of the laterally upstream rear wall, an open side wall, and an open top, the bottom wall lower surface having a flat horizontal profile, the laterally upstream rear wall meets the downstream bottom wall to form a curved transition section aligned laterally with respect to a direction of travel of the moving carrier web, the laterally upstream rear wall meets the laterally downstream bottom wall to form an angle (θ) in the range of 60 to 120 degrees, preferably 70° to 110°, and most preferably 80° to 100°, the laterally upstream rear wall is directed from the curved transition section upwardly away from the moving carrier web, and the laterally downstream bottom wall is directed from the curved transition section downwardly towards the moving carrier web; a thickness control device mounted on the mounting stand such that a lateral upstream rear wall of the angled rigid plate is transverse to a direction of travel of the moving carrier web; a vibrator attached to a laterally upstream rear wall of the angled rigid plate; a mounting stand for fixedly but adjustably maintaining the height of the angled plate on the movable carrier web to fixedly position the downstream end of the lateral bottom wall at a height of 0.1 to 2 inches, preferably 0.2 to 1.1 inches, and for fixedly but adjustably maintaining a mounting member angle "α" (alpha) of the angled plate relative to the movable carrier web within a range of 5° to 30°, typically 10° to 25°; a downstream end of the transverse bottom wall is transverse to a direction of travel of the slurry and the moving carrier web; a downstream end of the lateral bottom wall extends laterally across the movable web; A production line for a fiber reinforced cementitious panel, wherein the downstream end of the lateral bottom wall can be contacted with a fiber-containing slurry as it is transported on a moving carrier web.

[0270] Clause 2. The apparatus of clause 1, wherein the thickness control device comprises an angled rigid plate, the mounting frame comprises a U-shaped mounting stand for mounting the angled rigid plate on a support frame for the movable carrier web, the mounting stand having opposing upright members and tiltable lateral mounting members having opposing ends mounted to each upright member at a fixed but adjustable angle relative to the movable carrier web and at a fixed but adjustable height above the movable carrier web, the mounting frame also has a connector plate having an upper end portion attached to the lateral mounting members and a lower end portion attached to the rear wall of the angled rigid plate, and a vibrator (vibration motor) is also mounted to the rear wall of the angled rigid plate.

[0271] Clause 3. An apparatus as described in clause 2, wherein the U-shaped mounting frame has upright members fixedly attached to the cross members of the stationary frame, the U-shaped mounting frame also having tiltable lateral mounting members movably attached to the upright members, the tiltable lateral mounting members having opposed ends each rotatably mounted to a respective metal plate having holes for angular adjustment.

[0272] Clause 4. An apparatus as described in clause 3, wherein each of the opposing ends of the lateral mounting members is engaged with a selected hole in the tiltable lateral mounting member for angle adjustment to fixedly set the angle "α" (alpha) of the angled rigid plate relative to the movable carrier web.

[0273] Clause 5. The apparatus of clause 4, wherein the tiltable lateral mounting member includes a handle for lifting the vibration plate up and down to assist in adjusting the angle.

[0274] Clause 6. The apparatus of any one of clauses 1-5, wherein the length of the rigid angled plate in the machine direction "T" on the side contacting the slurry is typically about 2 inches to 24 inches, and the width of the oscillating angled plate transverse to the machine direction "T" can range from about 1 foot to 8 feet, with preferred widths of the metal plate ranging from about 2 feet to 6 feet, or from about 2 feet to 5 feet, or from about 3 feet to 4 feet.

[0275] Clause 7. The apparatus of any one of clauses 1-6, wherein on the sides for contacting the slurry, the thickness of the vibrating angled plate 95 is typically about 1 / 16 inch to 1 / 4 inch, and on the sides for contacting the slurry, the preferred thickness of the plate is about 1 / 8 inch, tapering gradually from 1 / 4 inch on the sides adapted and configured to move away from contacting the slurry to 1 / 16 inch on the edges for contacting the slurry.

[0276] Clause 8. An apparatus as described in any of clauses 1 to 7, wherein the depth to which the angled plate and vibration means are embedded in the fiber-containing slurry is for applying a force to the surface of the panel sufficient to control the thickness of the surface.

[0277] Clause 9. A means for depositing chopped fibers onto a slurry transported on a movable carrier web relative to a support frame; and means for embedding the fibers in the slurry on a movable carrier web to form a formed but unhardened fiber reinforced concrete panel by passing the slurry with the deposited fibers through an embedding device for use in a fiber reinforced concrete panel production line so as to contact a first plurality of axially spaced disks axially fixed to a first integrally formed elongated shaft rotatably fixed to the support frame and to contact a second plurality of axially spaced disks axially fixed to a second integrally formed elongated shaft rotatably fixed to the support frame, An apparatus as described in any one of clauses 1 to 8, wherein the first shaft is arranged to be horizontally aligned relative to the second shaft such that the disks interdigitate with each other and the peripheral portions of the first and second plurality of disks overlap each other when viewed from the side.

[0278] Clause 10. A mixer for mixing the cementitious slurry and the reinforcing fibers to form a fiber-containing slurry and supplying the fiber-containing slurry to a headbox; a headbox for depositing a layer of the fiber-containing slurry onto the moving carrier web; 9. The apparatus of any one of clauses 1-8, wherein the fiber slurry mixture deposited from the headbox has a slump of 4 to 11 inches as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter, and the resulting fiber slurry mixture also has a viscosity of less than 45,000 centipoise as measured using a Brookfield Viscometer, Model DV-II+Pro with a Spindle HA4 attachment operating at a speed of 20 RPM.

[0279] Clause 11. In the fiber reinforced cementitious panel production line of claim 1, a continuous process for controlling the thickness of a formed but not yet cured fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers, comprising: transporting the panels on a movable carrier web having a direction of travel relative to a support frame for supporting the movable carrier web; contacting the formed, but not yet cured, fiber reinforced cementitious panel, including the slurry and embedded chopped fibers, with a downstream end of a thickness control device, the thickness control device: An angled rigid plate; a mounting frame for mounting an angled rigid plate on a support frame for the moving carrier web; a flat, rigid support bed underlying the angled, rigid plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing slurry and to withstand a downward force imparted by the angled, rigid plate, preferably with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; the angled rigid plate has a laterally upstream rear wall, a laterally downstream bottom wall extending downstream from a lower end of the laterally upstream rear wall, an open side wall, and an open top, the bottom wall lower surface having a flat horizontal profile, the laterally upstream rear wall meets the downstream bottom wall to form a curved transition section aligned laterally with respect to a direction of travel of the moving carrier web, the laterally upstream rear wall meets the laterally downstream bottom wall to form an angle in the range of 60°-120°, preferably 70°-110°, and most preferably 80°-100°, the laterally upstream rear wall is directed from the curved transition section upwardly away from the moving carrier web, and the laterally downstream bottom wall is directed from the curved transition section downwardly towards the moving carrier web; the angled plate is mounted on the mounting stand such that a lateral upstream rear wall of the angled plate is transverse to a direction of travel of the moving carrier web; a vibrator is attached to the lateral upstream rear wall of the angled plate; A process in which a mounting stand maintains a fixed but adjustably height of the angled plate relative to the moving carrier web to fixedly position the downstream end of the bottom wall at a height of 0.1 to 2 inches, preferably 0.2 to 1.1 inches, above the moving carrier web, and maintains a fixed but adjustably angle of the angled plate relative to the moving carrier web less than 30°, typically an angle between 5° and 30°, preferably within the range of 10° to 25°, wherein the downstream end of the bottom wall contacts the fiber-containing slurry transported on the moving carrier web to control the thickness of the fiber-containing slurry.

[0280] Clause 12. The process of clause 11, wherein the angled plate is disposed across the entire width of the formed panel.

[0281] Clause 13. The process of clause 11 or 12, wherein the vibrating angled plate is positioned such that a functional edge of the plate remains in contact with the slurry at a depth of 0.05 inches or more relative to the slurry.

[0282] Clause 14. The process of any one of clauses 11-13, wherein the vibrating angled plate is vibrated by a vibrating motor 105 having a weight mounted at a distance from the metal plate, the distance of the rotating weight next to the metal plate being about 0.50 to 8 inches, about 1 to 7 inches, or about 2 to 6 inches, such that the vibration from the motor and the vibration of the plate remain in phase.

[0283] Clause 15. The process of any one of clauses 11 to 14, wherein the vibratory motor is fitted for use such that the rotational speed of the eccentric weight is typically from about 100 rpm to about 4000 rpm, and the eccentric weight attached to the rotating shaft rotates in a plane parallel to the face of the metal plate in contact with the cementitious slurry.

[0284] Clause 16. The method further comprises depositing chopped fibers on a slurry transported on a movable carrier web relative to a support frame; embedding the fibers in the slurry on a movable carrier web to form a formed but unhardened fiber reinforced concrete panel by passing the slurry with the deposited fibers through an embedding device for use in a fiber reinforced concrete panel production line so as to contact a first plurality of axially spaced disks axially fixed to a first integrally formed elongated shaft rotatably fixed to a support frame and to contact a second plurality of axially spaced disks axially fixed to a second integrally formed elongated shaft rotatably fixed to the support frame; 16. The process of any one of clauses 11-15, wherein the first shaft is arranged to be horizontally aligned relative to the second shaft such that the disks interdigitate and, when viewed from the side, the peripheral portions of the first and second plurality of disks overlap one another.

[0285] Clause 17. The process of clause 16, wherein the panel discharged from the fiber embedding station passes through a thickness control device.

[0286] Clause 18. The process of clause 16, further comprising passing the panel through at least two fiber embedding stations, and the panel discharged from the most downstream fiber embedding station being fed to a thickness control device.

[0287] Clause 19. Mixing a cementitious slurry and reinforcing fibers to form a fiber-containing slurry, and feeding the fiber-containing slurry to a headbox; depositing a layer of the fiber-containing slurry from the headbox onto a moving carrier web; 16. The process of any one of clauses 11-15, wherein the fiber slurry mixture deposited from the headbox has a slump of 4 to 11 inches as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter, and the resulting fiber slurry mixture also has a viscosity of less than 45,000 centipoise as measured using a Brookfield Viscometer, Model DV-II+Pro with a Spindle HA4 attachment operating at a speed of 20 RPM.

[0288] Clause 20. The process of clause 19, wherein the fiber slurry mixture deposited from the headbox has a slump of 4 to 11 inches as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter. The fiber slurry mixture also has a viscosity of less than 45,000 centipoise, preferably less than 30,000 centipoise, more preferably less than 15,000 centipoise, and most preferably less than 10,000 centipoise as measured using a Brookfield Viscometer, Model DV-II+Pro with a Spindle HA4 attachment operating at a speed of 20 RPM.

[0289] Clause 21. The process of clause 20, wherein the cementitious slurry and fibers are discharged from the headbox and uniformly deposited in a continuous layer 0.125 to 2 inches thick on a moving surface of a panel production line to produce a fiber reinforced cement panel, and an outer lip of the bottom wall of the angled rigid plate assembly is located approximately 0.01 inch to 0.25 inch below the top surface of the panel being formed.

[0290] Clause 22. The process of any one of clauses 11 to 21, wherein the dry cementitious powder comprises a reactive powder portion and an optional lightweight filler portion, the reactive portion comprising, on a dry basis, 35 to 75% by weight calcium sulfate alpha hemihydrate, 20 to 55% by weight hydraulic cement, 0.2 to 3.5% by weight lime, and 5 to 25% by weight active pozzolan.

[0291] Clause 23. The process of any one of clauses 11-22, wherein the slurry has a water to cement weight ratio of about 0.20 to about 0.7:1.

[0292] Clause 24. The process of any one of clauses 11-23, wherein the dry cementitious powder comprises 20-50% by weight of lightweight filler particles on a dry basis, the lightweight filler particles being selected from the group consisting of ceramic microspheres, glass microspheres, fly ash cenospheres and perlite.

[0293] Clause 25. The process of any one of clauses 11-24, wherein the moving carrier web moves at a speed of 1 to 100 feet per minute.

[0294] Clause 26. A production line for fiber-reinforced cementitious panels, comprising: A movable carrier web; a support frame for supporting a movable carrier web, the panels being transported on the movable carrier web having a travel direction relative to the support frame; a means for applying a facer, such as a glass mat, onto the fiber-containing cementitious slurry on a moving carrier web, the means for applying the facer being positioned across a width of the forming surface of the moving carrier web; 1. A horizontal thickness control device for controlling the thickness of a formed, but not yet cured, fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry, the fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers, on a moving carrier web, the device comprising: A horizontal thickness control device a rigid horizontal upper forming plate (e.g., horizontal forming plate 446), the rigid horizontal upper forming plate having a flat bottom surface, an upstream end, and a downstream end; a forming plate mounting frame for mounting a rigid horizontal upper forming plate in a horizontal orientation on a support frame for the movable carrier web, the rigid horizontal upper forming plate being mounted to the forming plate mounting frame; a flat, rigid support bed underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; a forming plate mounting frame for fixedly but adjustably maintaining the height of the rigid horizontal upper forming plate above the movable carrier web to fixedly position the flat bottom surface at a height of 0.1 to 2 inches, preferably 0.2 to 1.1 inches, above the movable carrier web, and for maintaining the rigid horizontal upper forming plate parallel to the movable carrier web; an upstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; a downstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; A production line for fiber reinforced cementitious panels in which the entire flat bottom surface can contact a facer on a fiber-containing slurry as it is transported on a moving carrier web.

[0295] Clause 27. Means for depositing chopped fibers onto a slurry transported on a movable carrier web relative to a support frame; and means for embedding the fibers in the slurry on a movable carrier web to form a formed but unhardened fiber reinforced concrete panel by passing the slurry with the deposited fibers through an embedding device for use in a fiber reinforced concrete panel production line so as to contact a first plurality of axially spaced disks axially fixed to a first integrally formed elongated shaft rotatably fixed to the support frame and to contact a second plurality of axially spaced disks axially fixed to a second integrally formed elongated shaft rotatably fixed to the support frame, 27. The apparatus described in clause 26, wherein the first shaft is arranged to be horizontally aligned relative to the second shaft so that the disks interdigitate with each other and when viewed from the side, the peripheral portions of the first and second plurality of disks overlap each other.

[0296] Clause 28. A mixer for mixing the cementitious slurry and the reinforcing fibers to form a fiber-containing slurry and supplying the fiber-containing slurry to a headbox; a headbox for depositing a layer of the fiber-containing slurry onto the moving carrier web; 27. The apparatus of claim 26, wherein the fiber slurry mixture deposited from the headbox has a slump of 4 to 11 inches as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter, and the resulting fiber slurry mixture also has a viscosity of less than 45,000 centipoise as measured using a Brookfield Viscometer, Model DV-II+Pro, equipped with a Spindle HA4 attachment operating at a speed of 20 RPM.

[0297] Clause 29. An apparatus as described in any one of clauses 26 to 28, wherein the upstream end of the horizontal forming plate is beveled.

[0298] Clause 30. A process for making a fiber reinforced cementitious panel, comprising: transporting a fiber-containing slurry for the panels on a moving carrier web, the moving carrier web being supported by a support frame, the panels being transported on the moving carrier web having a travel direction relative to the support frame; applying a facer, such as a glass mat, onto the fiber-containing cementitious slurry on the moving carrier web across the width of the forming surface of the moving carrier web to cover the forming surface; passing a forming surface covered with a facer under a horizontal thickness control device for controlling a thickness of a formed but not yet cured fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on a moving carrier web; A thickness control device, a rigid horizontal upper forming plate (e.g., horizontal forming plate 446), the rigid horizontal upper forming plate having a flat bottom surface, an upstream end, and a downstream end; a forming plate mounting frame for mounting a rigid horizontal upper forming plate in a horizontal orientation on a support frame for the movable carrier web, the rigid horizontal upper forming plate being mounted to the forming plate mounting frame; a flat, rigid support bed underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a deflection of less than 0.03 inches, preferably less than 0.01 inches, preferably less than 0.003 inches; and controlling a thickness of the formed but uncured fiber reinforced cementitious panel by contacting the formed but uncured fiber reinforced cementitious panel covered with a facer, the fiber containing cementitious slurry, with a bottom surface of a rigid horizontal upper forming plate; a mounting frame for fixedly but adjustably maintaining the height of the rigid horizontal upper forming plate on the movable carrier web to fixedly position the flat bottom surface at a height of 0.1 to 2 inches above the movable carrier web and for maintaining the plate parallel to the movable carrier web; an upstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; a downstream end of the flat bottom surface extends transversely across the moving web relative to a direction of travel of the moving web; A process in which the entire flat bottom surface contacts a facer on a fiber-containing slurry as it is carried on a moving carrier web.

[0299] Clause 31. The method further comprises depositing chopped fibers on a slurry transported on a movable carrier web relative to a support frame; embedding the fibers in the slurry on a movable carrier web to form a formed but unhardened fiber reinforced concrete panel by passing the slurry with the deposited fibers through an embedding device for use in a fiber reinforced concrete panel production line so as to contact a first plurality of axially spaced disks axially fixed to a first integrally formed elongated shaft rotatably fixed to a support frame and to contact a second plurality of axially spaced disks axially fixed to a second integrally formed elongated shaft rotatably fixed to the support frame; The process of claim 30, wherein the first shaft is arranged to be horizontally aligned relative to the second shaft such that the disks interdigitate and, when viewed from the side, peripheral portions of the first and second plurality of disks overlap one another.

[0300] Clause 32. Mixing a cementitious slurry and reinforcing fibers to form a fiber-containing slurry, and feeding the fiber-containing slurry to a headbox; depositing a layer of the fiber-containing slurry from the headbox onto a moving carrier web; 31. The process of claim 30, wherein the fiber slurry mixture deposited from the headbox has a slump of 4 to 11 inches as measured according to a Slump Test using a pipe 4 inches high and 2 inches in diameter, and the resulting fiber slurry mixture also has a viscosity of less than 45,000 centipoise as measured using a Brookfield Viscometer, Model DV-II+Pro, with a Spindle HA4 attachment operating at a speed of 20 RPM.

[0301] Clause 33. The process of clause 32, wherein the cementitious slurry and fibers are discharged from the headbox and uniformly deposited in a continuous layer 0.125 to 2 inches thick on a moving surface of a panel production line to produce a fiber reinforced cement panel, and an outer lip of the bottom wall of the angled rigid plate assembly is located approximately 0.01 inch to 0.25 inch below the top surface of the panel being formed.

[0302] Clause 34. The process of any one of clauses 30-33, wherein the moving carrier web moves at a speed of 1 to 100 feet per minute.

[0303] Clause 35. The process of any one of clauses 30-34, wherein the slurry has a water to cement weight ratio of about 0.20 to about 0.7:1.

[0304] Clause 36. The process of any one of clauses 30 to 35, wherein the dry cementitious powder comprises a reactive powder portion and an optional lightweight filler portion, the reactive portion comprising, on a dry basis, 35 to 75% by weight calcium sulfate alpha hemihydrate, 20 to 55% by weight hydraulic cement, 0.2 to 3.5% by weight lime, and 5 to 25% by weight active pozzolan.

[0305] Clause 37. The process of any one of clauses 30-36, wherein the dry cementitious powder comprises 20-50% by weight of lightweight filler particles on a dry basis, the lightweight filler particles being selected from the group consisting of ceramic microspheres, glass microspheres, fly ash cenospheres and perlite.

[0306] Clause 38. The process of any one of clauses 30-33, wherein the fixed horizontal forming plate is installed to position the lower surface of the fixed horizontal forming plate at a height that is less than 0.001 to 0.05 inches, preferably less than 0.01 to 0.03 inches, of the target thickness of the FRC panel.

[0307] While particular embodiments of the present fiber-reinforced cementitious structural floor panel production have been shown and described, those skilled in the art will appreciate that changes and modifications can be made therein without departing from the invention in its broader aspects and as set forth in the following claims.

Claims

1. A production line for fiber reinforced cementitious panels, comprising: A movable carrier web; a support frame for supporting the movable carrier web, the panels being transported on the movable carrier web having a travel direction relative to the support frame; a thickness control device for controlling a thickness of a formed, but not yet cured, fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on the moving carrier web, the thickness control device comprising: An angled rigid plate; a mounting frame for mounting said angled rigid plate on said support frame for said movable carrier web; a flat, rigid support bed beneath the moving carrier web underlying the angled, rigid plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing slurry and to withstand a downward force imparted by the angled, rigid plate with a vertical deflection of less than 0.03 inches relative to the moving carrier web; the angled rigid plate has a laterally upstream rear wall, a laterally downstream bottom wall extending downstream from a lower end of the laterally upstream rear wall, an open sidewall, and an open top, a lower surface of the laterally downstream bottom wall having a flat horizontal profile, the laterally upstream rear wall meets the laterally downstream bottom wall to form a curved transition section aligned laterally with respect to a direction of travel of the moving carrier web, the laterally upstream rear wall meets the laterally downstream bottom wall to form an angle (θ) in the range of 60 to 120 degrees, the laterally upstream rear wall is directed from the curved transition section upwardly away from the moving carrier web, and the laterally downstream bottom wall is directed from the curved transition section downwardly towards the moving carrier web; a thickness control device mounted to the mounting frame such that a lateral upstream rear wall of the angled rigid plate is transverse to the direction of travel of the movable carrier web; a vibrator attached to a laterally upstream rear wall of the angled rigid plate; said mounting frame for fixedly but adjustably maintaining a height of said angled plate on said movable carrier web to fixedly position the downstream end of said lateral downstream bottom wall at a height of 0.1 to 2 inches on said movable carrier web, and for fixedly but adjustably maintaining a mounting member angle "α" (alpha) of said angled plate relative to said movable carrier web at 5° to 30°; the downstream end of the lateral downstream bottom wall is transverse to the direction of travel of the slurry and moving carrier web; the downstream end of the laterally downstream bottom wall extends laterally across the movable web; A fiber reinforced cementitious panel production line, wherein the downstream end of the laterally downstream bottom wall can be contacted with the fiber-containing slurry as it is transported on the moving carrier web.

2. 2. The fiber reinforced cementitious panel production line of claim 1, wherein the thickness control device comprises the angled rigid plate, the mounting frame comprises a U-shaped mounting stand for mounting the angled rigid plate on the support frame for the movable carrier web, the mounting stand having opposed upright members and tiltable lateral mounting members having opposed ends mounted to their respective upright members at a fixed but adjustable angle relative to the movable carrier web and at a fixed but adjustable height above the movable carrier web, the mounting frame also has a connector plate having an upper end portion attached to the lateral mounting members and a lower end portion attached to the lateral upstream rear wall of the angled rigid plate, and the vibrator (vibration motor) is also mounted to the lateral upstream rear wall of the angled rigid plate.

3. 3. The fiber reinforced cementitious panel production line of claim 2, wherein the U-shaped mounting stand has an upright member fixedly attached to a cross member of a stationary frame, the U-shaped mounting stand also having the tiltable lateral mounting members movably attached to the upright member, the tiltable lateral mounting members having opposing ends each rotatably mounted to a respective metal plate having holes for angular adjustment.

4. 4. The fiber reinforced cementitious panel production line of claim 3, wherein each of the opposing ends of the lateral mounting members is mated with a selected hole in the tiltable lateral mounting member for angle adjustment to fixedly set the angle "α" (alpha) of the angled rigid plate relative to the movable carrier web.

5. A production line for fiber reinforced cementitious panels, comprising: A movable carrier web; a support frame for supporting the movable carrier web, the panels being transported on the movable carrier web having a travel direction relative to the support frame; a means for applying a glass mat, fabric, or nonwoven fiber facer onto the fiber-containing cementitious slurry on the moving carrier web, the means for applying the facer being positioned across a width of a forming surface of the moving carrier web; a horizontal thickness control device for controlling a thickness of a formed, but not yet cured, fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on said moving carrier web, said horizontal thickness control device comprising: The horizontal thickness control device comprises: a rigid horizontal upper forming plate, said rigid horizontal upper forming plate having a flat bottom surface, an upstream end and a downstream end; a forming plate mounting frame for mounting said rigid horizontal upper forming plate in a horizontal orientation on said support frame for said movable carrier web, said rigid horizontal upper forming plate being mounted to said forming plate mounting frame; a flat, rigid support bed underlying the moving carrier web underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a vertical deflection of less than 0.03 inches relative to the moving carrier web; a horizontal thickness control device for maintaining a fixed but adjustable height of the rigid horizontal upper forming plate on the moving carrier web and for maintaining the rigid horizontal upper forming plate parallel to the moving carrier web, the forming plate mounting frame fixedly positions the flat bottom surface at a height of 0.1 to 2 inches on the moving carrier web to provide a constant gap between the lower surface of the rigid horizontal upper forming plate and the moving carrier web; the means for applying the facer is upstream of the horizontal thickness control device; the upstream end of the flat bottom surface extends transversely across the moving carrier web relative to a direction of travel of the moving carrier web; the downstream end of the flat bottom surface extends transversely across the moving carrier web relative to a direction of travel of the moving carrier web; the entire flat bottom surface can contact the facer on the fiber-containing slurry as it is transported on the moving carrier web; A production line for fiber reinforced cementitious panels, comprising a side wiper on the side of the rigid horizontal upper forming plate for blocking the fiber-containing cementitious slurry at the edge of the fiber reinforced cementitious panel to prevent excess slurry from flowing beyond the edge.

6. 1. A process for making a fiber reinforced cementitious panel comprising: transporting a fiber-containing slurry for a panel on a moving carrier web, the moving carrier web being supported by a support frame, the panel being transported on the moving carrier web having a travel direction relative to the support frame; applying a facer onto the fiber-containing cementitious slurry on the moving carrier web across a width of the forming surface of the moving carrier web to cover the forming surface; passing the facer covered forming surface under a horizontal thickness control device for controlling a thickness of a formed but not yet hardened fiber reinforced cementitious panel comprising a fiber-containing cementitious slurry comprising a cementitious material and embedded chopped fibers on the moving carrier web; The thickness control device comprises: a rigid horizontal upper forming plate, said rigid horizontal upper forming plate having a flat bottom surface, an upstream end, and a downstream end; a forming plate mounting frame for mounting said rigid horizontal upper forming plate in a horizontal orientation on said support frame for said movable carrier web, said rigid horizontal upper forming plate being mounted to said forming plate mounting frame; a flat, rigid support bed underlying the moving carrier web underlying the rigid horizontal upper forming plate, the flat, rigid support bed being sufficiently adapted and configured to support the fiber-containing cementitious slurry and to withstand a downward force imparted by the rigid horizontal upper forming plate with a vertical deflection of less than 0.03 inches relative to the moving carrier web; and controlling a thickness of the formed but uncured fiber reinforced cementitious panel by contacting the formed but uncured fiber reinforced cementitious panel covered with the facer, the fiber reinforced cementitious panel including a fiber-containing cementitious slurry, with a bottom surface of the rigid horizontal upper forming plate; The rigid horizontal upper forming plate is provided on a side thereof with a side wiper for blocking the fiber-containing cementitious slurry at an edge of the fiber-reinforced cementitious panel to prevent excess slurry from flowing over the edge, said mounting frame for fixedly but adjustably maintaining the height of said rigid horizontal upper forming plate on said movable carrier web to fixedly position said flat bottom surface at a height of 0.1 to 2 inches above said movable carrier web, and for maintaining said rigid horizontal upper forming plate parallel to said movable carrier web; the upstream end of the flat bottom surface extends transversely across the moving carrier web relative to a direction of travel of the moving carrier web; a downstream end of said flat bottom surface extending laterally across said moving carrier web relative to a direction of travel of said moving carrier web.

7. prior to applying a facer onto the fiber-containing cementitious slurry on the moving carrier web to cover the forming surface, passing the fiber-containing cementitious slurry on the moving carrier web through a thickness control device having a rigid plate angled relative to the forming surface of the moving carrier web, a U-shaped mounting stand for mounting the angled rigid plate on the support frame, and a vibrator attached to the angled rigid plate; 7. The process of claim 6, wherein the angled plate is disposed across the width of the formed panel and the vibrating angled plate is positioned such that a functional edge of the plate remains in contact with the slurry at a depth of 0.05 inches or more into the slurry.

8. 7. The process of claim 6, further comprising vibrating the fiber-containing cementitious slurry with a vibrator located immediately before the rigid horizontal upper forming plate and / or below a flat rigid support bed below the rigid horizontal upper forming plate.

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