System and method for measuring foam density

Abstract

A process and system for measuring foam density is provided. A weir is disposed within a housing such that the weir separates an interior of the housing into an inlet portion and an outlet portion. A pressure measurement conduit includes an inlet positioned to receive foam from the inlet portion of the interior. A pressure sensor is configured to measure a pressure of the foam in the pressure measurement conduit at a measurement location located below the inlet of the pressure measurement conduit.

Description

Cross-reference to related applications

[0001] This application relates to and claims priority to U.S. Provisional Application No. 63 / 601,386, filed November 21, 2023 with the United States Patent and Trademark Office, the entire contents of which are incorporated herein by reference. Background Technology

[0002] Many thin paper products (such as facial tissues, toilet paper, paper towels, and industrial wipes) are produced using a wet-laid process. Wet-laid fiber webs are prepared by depositing an aqueous suspension of pulp fibers onto a formed fabric, followed by removing the water from the newly formed fiber web.

[0003] To improve various properties of thin paper fiber webs, fiber webs are also formed using a foam forming process. During the foam forming process, a foamed fiber suspension is generated and spread onto a moving porous conveyor belt to produce an embryonic web. Foam-formed fiber webs can exhibit improvements in bulk, tensile strength, thickness, and / or absorbency. Besides thin paper fiber webs, foam forming can be used to manufacture all different types of fiber webs and products. For example, relatively long fibers and synthetic fibers can be incorporated into fiber webs using the foam forming process. Therefore, the foam forming process is more versatile than many wet web forming processes.

[0004] In some conventional foam molding systems, measuring foam density can be difficult. Furthermore, foam is a two-phase fluid with both a liquid and a gaseous phase. Measuring foam density can depend not only on the temperature of the liquid phase but also on the pressure on the gas phase and the ratio of the liquid to gas phases within the foam. The flow rate of the foam in the system can also vary, which may make density measurements via a fixed column inaccurate.

[0005] A system for improving foam density measurement would be useful. Summary of the Invention

[0006] Generally, this disclosure relates to improved methods and systems for measuring foam density. A density measuring component for a foam forming system includes a housing having an inlet for foam and an outlet for foam. The inlet of the housing is located on one side of a weir, and the outlet of the housing is located on the opposite side of the foam. Foam can enter the housing via the inlet of the housing by gravity or pressure. The weir can be configured such that foam in the housing flows through the weir between the inlet and outlet of the housing. Thus, the weir can control the level of foam on the inlet side of the housing. A pressure measuring conduit can be coupled to the housing. Furthermore, the inlet of the pressure measuring conduit can be positioned on the inlet side of the housing, for example, such that foam on the inlet side of the housing (e.g., foam that has not yet flowed through the weir) can enter the pressure measuring conduit at the inlet of the pressure measuring conduit. Foam can flow from the inlet of the pressure measuring conduit to the outlet of the pressure measuring conduit. A pressure sensor can be configured to measure the pressure of the foam in the pressure measuring conduit. Furthermore, the pressure sensor can measure the pressure of the foam in the pressure measuring conduit at a measurement location, which can be located below the inlet and outlet of the pressure measuring conduit. For example, the pressure measuring conduit can be U-shaped, and a pressure sensor can be configured to measure the pressure of the foam at the bottom of the U-shaped pressure measuring conduit. Based at least in part on the pressure measurement from the pressure sensor, the density of the foam can be estimated. The density measuring assembly can advantageously provide a reliable, low-cost mechanism for measuring the density of foam in a foam forming system. Furthermore, the density measuring assembly can advantageously provide accurate density measurements for various inlet flow rates of the foam and / or advantageously avoid foam decomposition during density measurement.

[0007] In one example embodiment, a density measurement component for a foam forming system includes a housing having an inlet for foam to enter the housing and an outlet for foam to exit the housing. The interior of the housing is adjacent to the ambient atmosphere. A weir is disposed within the housing such that it separates the interior of the housing into an inlet portion and an outlet portion. The inlet is located at the inlet portion of the housing, allowing foam from the inlet to flow into the inlet portion, and the outlet is located at the outlet portion of the housing, allowing foam from the outlet portion to flow into the outlet portion. The weir is configured such that foam within the interior of the housing flows through the weir between the inlet and outlet portions. A pressure measuring conduit includes an inlet positioned to receive foam from the inlet portion of the housing and an outlet for foam from the pressure measuring conduit. A pressure sensor is configured to measure the pressure of the foam in the pressure measuring conduit at a measuring location located below the inlet and outlet of the pressure measuring conduit.

[0008] In another example embodiment, the foam forming system includes a headbox and a density measuring assembly configured to measure the density of foam in the headbox. The density measuring assembly includes a housing having an inlet and an outlet for the foam. The interior of the housing is adjacent to the ambient atmosphere. A weir is disposed within the housing. The weir is configured such that foam within the housing flows through the weir between the inlet and outlet of the housing. A pressure measuring conduit includes an inlet for receiving foam from the interior of the housing. The inlet of the pressure measuring conduit is located on the inlet side of the housing. A pressure sensor is configured to measure the pressure of the foam in the pressure measuring conduit at a measuring location located below the inlet of the pressure measuring conduit.

[0009] Other features and aspects of this disclosure are discussed in more detail below. Attached Figure Description

[0010] The full and practical disclosure of this invention is set forth in more detail in the remainder of the specification, including with reference to the accompanying drawings, in which:

[0011] Figure 1 This is a schematic diagram of a system and process for forming a fiber web from a foamed material suspension, according to an example embodiment of the present disclosure;

[0012] Figure 2 This is a schematic diagram of a system and process for depositing a foamed material suspension onto a shaped surface according to an example embodiment of the present disclosure;

[0013] Figure 3 This is a perspective view of a system and process for measuring foam density during foam forming of a nonwoven fiber web, according to an example embodiment of this disclosure;

[0014] Figure 4 It is used to measure foam density during the foam formation process of nonwoven fiber webs. Figure 3 A top-view plan of an example system and process;

[0015] Figure 5 It is used to measure foam density during the foam formation process of nonwoven fiber webs. Figure 3 Example front view of the system and process.

[0016] The repeated use of reference numerals in this specification and drawings is intended to indicate the same or similar features or elements of the invention.

[0017] definition

[0018] When describing elements of this disclosure or its preferred embodiments, the articles “a,” “an,” “the,” and “the” are intended to indicate the presence of one or more elements. As used herein, the terms “comprising” and “including” are intended to be inclusive in a manner similar to the term “containing.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). As used herein throughout the specification and claims, approximate language is applied to modify any quantitative expression that allows for variation without altering its underlying function. Thus, values ​​modified by one or more terms such as “about,” “approximately,” and “substantially” are not limited to specified precise values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. For example, approximate language may refer to a range of ten percent (10%).

[0019] As used herein, the term "foam-formed product" refers to a product formed from a suspension of a mixture of solids, liquids and dispersed air bubbles.

[0020] As used herein, the term “foam forming process” refers to a process used to manufacture products involving suspensions of mixtures comprising solids, liquids and dispersed bubbles.

[0021] As used herein, the term "foaming fluid" means any one or more known fluids that are compatible with other components in the foam forming process. Suitable foaming fluids include, but are not limited to, water.

[0022] As used in this article, the term "foam half-life" refers to the time elapsed until half of the initial foam mass has reverted to liquid water.

[0023] As used herein, the term "layer" refers to a structure that provides a region of substrate in the height direction of the substrate, and that structure consists of similar components and structures.

[0024] As used in this article, the term "nonwoven fiber web" refers to a fiber web with a structure of individual fibers or threads that are interwoven, but the interweaving pattern is not as clearly discernible as that of a knitted fiber web.

[0025] As used herein, unless otherwise expressly indicated, when referring to material compositions, the terms “percentage,” “%,” “weight percentage,” or “percentage by weight” each refer to the weight amount of a component as a percentage of the total amount, unless otherwise expressly indicated.

[0026] The term "personal care absorbent articles" as used herein refers to articles designed and / or adapted to be placed close to or adjacent to the wearer's body (i.e., adjacent to the body) to absorb and contain various liquid, solid, and semi-solid excretions from the body. Examples include, but are not limited to, diapers, diaper pants, training pants, joggers, swim trunks, feminine hygiene products (including but not limited to menstrual pads or pants), incontinence products, medical clothing, surgical pads, and bandages, etc.

[0027] As used herein, the term “superabsorbent material” refers to a water-swellable, water-insoluble organic or inorganic material comprising superabsorbent polymers and compositions thereof, which, under most favorable conditions, can absorb at least about ten times (10X) its weight, or at least about fifteen times (15X) its weight, or at least about twenty-five times (25X) its weight in an aqueous solution containing nine-tenths (0.9) wt% sodium chloride.

[0028] As used herein, the term "longitudinal" refers to the direction of travel of the forming surface on which the fibers are deposited during the forming of a nonwoven fiber web.

[0029] As used in this article, the term "lateral" refers to a direction perpendicular to the longitudinal direction as defined above.

[0030] As used herein, the term "pulp" refers to fibers derived from natural sources such as woody and non-woody plants. Woody plants include, for example, deciduous and coniferous trees. Non-woody plants include, for example, cotton, flax, fine-stemmed needlegrass, milkweed, rice straw, jute, hemp, and bagasse. Pulp fibers may include hardwood fibers, softwood fibers, and mixtures thereof.

[0031] As used herein, the term "average fiber length" refers to the average length of a fiber, fiber bundle, and / or fibrous material as determined by measurement using microscopic techniques. A sample of at least 20 randomly selected fibers is separated from a fiber liquid suspension. The fibers are placed on a microscope slide prepared to suspend the fibers in water. A staining dye is added to the suspended fibers to color the cellulose-containing fibers, thereby distinguishing or separating them from synthetic fibers. The slide is placed under a Fisher Stereomaster II microscope—S19642 / S19643 series. Measurements of the 20 fibers in the sample are performed at 20X linear magnification using a 0–20 mil scale, and the average length, minimum and maximum length, and deviation or coefficient of variation are calculated. In some cases, the average fiber length is calculated as a weighted average length of the fibers (e.g., fibers, fiber bundles, fibrous materials), determined using equipment such as the Kajaani FS-200 fiber analyzer available from Kajaani Oy Electronics, Kajaani, Finland. According to the standard testing procedure, the samples are treated with an impregnation solution to ensure the absence of fiber bundles or debris. Each sample is decomposed in hot water and diluted to a suspension of approximately 0.001%. When testing using the standard Kajaani fiber analysis test procedure, each test sample is drawn from the diluted suspension in portions of approximately 50 ml to 100 ml. The weighted average fiber length can be an arithmetic mean, a length-weighted mean, or a weight-weighted mean, and can be expressed by the following equation:

[0032]

[0033] in

[0034] k = maximum fiber length

[0035] x i =Fiber length

[0036] n i = The number of fibers with length xi

[0037] n = the total number of fibers measured.

[0038] One characteristic of the average fiber length data measured by the Cajani fiber analyzer is that it does not distinguish between different types of fibers. Therefore, the average length represents the average length of all different types (if any) of fibers in the sample.

[0039] As used herein, the term "short fiber" refers to discontinuous fibers made from synthetic polymers such as polypropylene, polyester, post-consumer recycled (PCR) fibers, nylon, etc., and those that are not hydrophilic can be treated to become hydrophilic. Short fibers can be chopped fibers, etc. Short fibers can have cross-sections such as circular, bicomponent, multicomponent, molded, hollow, etc. Detailed Implementation

[0040] Those skilled in the art will understand that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this disclosure.

[0041] Generally, this disclosure relates to a system and method for measuring the density of foam in a foam forming system. For example, a density measuring component can be installed in the foam forming system and can receive a portion of the pressurized foam flow from the foam forming system. Furthermore, the foam from the foam forming system can be guided into the housing of the density measuring component. A weir within the housing divides the interior of the housing into an inlet section and an outlet section. Foam can enter the housing at the inlet section inside. As the foam fills the inlet section inside, it may overflow the weir to the outlet section inside, where it can exit the housing. The interior of the housing may be adjacent to the ambient atmosphere. Therefore, the pressurized foam entering the housing can be regulated to the ambient pressure within the housing. Thus, the weir and the open housing help prevent or reduce head pressure changes caused by flow in the pressure measuring conduit. The inlet of the pressure measuring conduit is located at the inlet section inside, and the outlet of the pressure measuring conduit may be located below the inlet. Therefore, the pressure measuring conduit can have a head difference between its inlet and outlet, which can cause a supplementary flow of foam from the inlet section inside through the pressure measuring conduit. A pressure sensor is configured to measure the pressure of foam within the pressure measuring conduit at measurement locations located below the inlet and outlet of the conduit. The pressure measurement from the pressure sensor can be used to calculate the density of the foam within the pressure measuring conduit.

[0042] The systems and processes disclosed herein offer various advantages and beneficial effects. For example, the weir can advantageously convert the variable foam flow from the foam forming system into a nominal constant head pressure in the pressure measuring conduit. Therefore, variations in the head pressure measured by the pressure sensor can be advantageously reduced. Furthermore, the flow of foam through the pressure measuring conduit can be controlled, for example, by controlling the vertical distance between the inlet and outlet of the pressure measuring conduit, to further reduce variations in the head pressure measured by the pressure sensor. In measuring foam density, for example, relative to a conventional system measuring a stationary fluid column, the density measuring component can also advantageously limit or prevent foam separation.

[0043] refer to Figure 1 and Figure 2Example embodiments of systems and processes according to various aspects of this disclosure are shown. Generally, during this process, solid materials such as fibers and / or superabsorbent particles, water, and foaming agents are added to a reservoir and mixed until the desired air content, bubble size / foam stability, and solid dispersion, such as a fiber dispersion, are achieved. The fiber-containing foam may then optionally be diluted during this process, especially when a recirculated stream is present. In one example aspect, the air content of the foaming suspension is between about thirty percent (30%) and about sixty-five percent (65%). As will be described below, example aspects of the processes and systems of this disclosure relate to separating and managing foam from free air, for example, during the foaming of nonwoven fiber webs.

[0044] Figure 1 Examples are given of systems and processes for producing foamed fiber suspensions and for forming fiber webs from foamed fiber suspensions. It should be understood that... Figure 1 The example system shown is provided by way of example, and any suitable fiber web forming system can be used according to this disclosure. Figure 1 As shown, the system may include a mixing tank 12 configured to form a foamed fiber suspension. The foamed fiber suspension can then be supplied to a headbox or fiber web forming system 10, which deposits the foamed fiber suspension onto a porous forming surface 26 for forming a fiber web 14. The mixing tank 12 may be connected to a water supply device 22 for supplying water to the tank and a foaming agent or surfactant supply device 24 for supplying surfactants to the tank 12. Fiber ingredients may also be supplied to the tank 12 and combined with water and surfactants. The aqueous solution formed by combining surfactants and water can be stirred and shaped into foam for forming the foamed fiber suspension. As described above, various other materials besides fibers may be combined in the tank 12. For example, such other materials may include superabsorbent particles, etc.

[0045] Surfactants or blowing agents may include, for example, any suitable surfactant. In one example embodiment, the blowing agent may include, for example, sodium lauryl sulfate, also known as sodium lauryl polyoxyethylene ether sulfate or sodium lauryl ether sulfate. Other blowing agents include sodium dodecyl sulfate or ammonium lauryl sulfate. In other example embodiments, the blowing agent may include any suitable cationic surfactant and / or amphoteric surfactant. For example, other blowing agents include fatty acid amines, amides, amine oxides, fatty acid quaternary compounds, etc. In one example embodiment, a nonionic surfactant is used. Nonionic surfactants may include, for example, alkyl polyglycosides. In one aspect, for example, the surfactant may be a C8 alkyl polyglycoside, a C10 alkyl polyglycoside, or a mixture of C8 alkyl polyglycosides and C10 alkyl polyglycosides.

[0046] Foaming agents are typically present in amounts greater than about 11 percent (0.1%) by weight, such as greater than about 1 / 2 percent (0.5%) by weight, such as greater than about 17 percent (0.7%) by weight, in combination with water. One or more foaming agents are typically present in amounts from about 1 percent (0.01%) to about 5 percent (5%) by weight, such as at most about 2 percent (2%) by weight.

[0047] When a foaming agent and water are combined, the mixture can be blended or otherwise subjected to forces capable of forming foam. Foam typically refers to an aggregate of hollow cells or air bubbles.

[0048] Foam density can vary depending on the specific application and various factors, including the fiber composition used. In one example embodiment, the foam density can be greater than about 200 g / L, such as greater than about 250 g / L, such as greater than about 300 g / L. Foam density is typically less than about 600 g / L, such as less than about 500 g / L, such as less than about 400 g / L, such as less than about 350 g / L. In one example embodiment, a lower density foam is used, typically less than about 350 g / L, such as less than about 340 g / L, such as less than about 330 g / L. Foams can typically have an air content of, for example, greater than about 40 percent (40%) at standard temperature and pressure (STP), such as greater than about 50 percent (50%), such as greater than about 60 percent (60%). An air content is typically less than about 75 percent (75%) by volume, such as less than about 70 percent (70%) by volume, such as less than about 65 percent (65%) by volume.

[0049] The foam can be formed in the presence of the fiber ingredients; alternatively, the foam can be formed first and then combined with the fiber ingredients. Generally, any fiber capable of preparing a substrate can be used, such as thin paper fiber webs or other similar types of nonwoven materials.

[0050] Fibers suitable for manufacturing fiber webs include any natural or synthetic cellulose fibers, including but not limited to: non-wood fibers such as cotton, abaca, kenaf, sabai grass, flax, esparto grass, rice straw, jute, bagasse, milkweed fiber, and pineapple leaf fiber; and woody or pulp fibers, such as those obtained from deciduous and coniferous trees, including softwood fibers such as northern and southern softwood kraft paper fibers; and hardwood fibers such as eucalyptus, maple, birch, and aspen. Pulp fibers can be prepared in high-yield or low-yield forms and can be pulped by any known method, including kraft paper pulping, sulfite pulping, high-yield pulping methods, and other known pulping methods. Fibers prepared by organic solvent pulping methods may also be used.

[0051] A portion of the fiber, such as fibers comprising at most 100% (100%) or less by dry weight, or from about 5% (5%) to about 30% (30%) by dry weight, may be synthetic fibers, such as rayon, polyolefin fibers, polyester fibers, bicomponent core-sheath fibers, multicomponent adhesive fibers, etc. The fiber may be virgin or regenerated. The fiber may be short fiber and may have an average length of about three millimeters (3 mm) to about one hundred and fifty millimeters (150 mm). An exemplary polyethylene fiber is Fybrel, available from Minifibers, Inc. (Jackson City, Tenn.). ® When containing synthetic polymer fibers, the fiber web can be thermally bonded at the fiber intersections.

[0052] Synthetic cellulose fiber types include all kinds of rayon and other fibers derived from self-adhesive or chemically modified cellulose. Chemically treated natural cellulose fibers, such as mercerized pulp, chemically hardened or cross-linked fibers, or sulfonated fibers, can be used. To obtain good mechanical properties when using papermaking fibers, it may be desirable for the fibers to be relatively undamaged and substantially unrefined or only lightly refined. While recycled fibers can be used, virgin fibers are generally useful due to their mechanical properties and lack of contaminants. Mercerized fibers, regenerated cellulose fibers, microbially produced cellulose, rayon, and other cellulose materials or cellulose derivatives can be used. Suitable papermaking fibers may also include regenerated fibers, virgin fibers, or mixtures thereof. In some example embodiments that can achieve high bulk and good compressibility, the fibers may have a Canadian standard freeness of at least 200, more specifically at least 300, even more specifically at least 400, and most specifically at least 500 (500).

[0053] Other papermaking fibers that can be used include waste or recycled fibers and high-yield fibers. High-yield pulp fibers are those papermaking fibers produced by pulping methods that provide a yield of about 65% or higher, more specifically about 75% or higher, and even more specifically about 75% to about 95% (95%). Yield is the amount of processed fiber obtained as a percentage of the initial wood mass. Such pulping methods include bleached chemithermomechanical pulp (BCTMP), chemithermomechanical pulp (CTMP), pressure / pressure thermomechanical pulp (PTMP), thermomechanical pulp (TMP), thermomechanical chemical pulp (TMCP), high-yield sulfite pulp, and high-yield kraft pulp, all of which result in fibers with a high lignin content. High-yield fibers are well known for their stiffness in both dry and wet conditions relative to typical chemically pulped fibers.

[0054] Fiber webs can also be formed without significant internal fiber-to-fiber bonding strength. In this regard, the fiber formulation used to form the base fiber web can be treated with a chemical detacker. The detacker can be added to the foamed fiber slurry during the pulping process or directly to the headbox. Suitable detackers that can be used include cationic detackers, such as aliphatic dialkyl quaternary ammonium salts, monoaliphatic alkyl tertiary ammonium salts, primary amine salts, imidazoline quaternary ammonium salts, silicone quaternary ammonium salts, and unsaturated aliphatic alkyl ammonium salts. Other suitable detackers are disclosed in U.S. Patent No. 5,529,665 to Kaun, the entire contents of which are incorporated herein by reference. In particular, Kaun discloses the use of cationic siloxane compositions as detackers.

[0055] In one example embodiment, the detacking agent used in the process of this disclosure may be an organic quaternary ammonium chloride, particularly an organosilicon-based amine salt of quaternary ammonium chloride. For example, the detacking agent may be PROSOFT.RTM.TQ1003, sold by Hercules Corporation. The detacking agent may be added to the fiber slurry in an amount from about one kilogram per metric ton (1 kg / metric ton) to about ten kilograms per metric ton (10 kg / metric ton) of fiber present in the slurry.

[0056] In an alternative example embodiment, the detacker may be an imidazoline-based agent. Imidazolline-based detackers are available, for example, from Witco Corporation. The imidazoline-based detacker may be added in amounts from approximately 2 kg / metric ton (2.0 kg / ton) to approximately 15 kg / metric ton (15 kg / ton).

[0057] Other optional chemical additives may also be added to the aqueous papermaking ingredients or the formed preform web to impart additional beneficial effects to the product and process. The following materials are included as examples of additional chemicals that can be applied to the web. The chemicals are included as examples and are not intended to limit the scope of this disclosure. These chemicals may be added at any point in the papermaking process.

[0058] Additional types of chemicals that can be added to paper fiber webs include, but are not limited to, absorbent additives typically in the form of cationic, anionic, or nonionic surfactants; humectants and plasticizers, such as low molecular weight polyethylene glycol; and polyhydroxy compounds, such as glycerin and propylene glycol. Materials that provide skin health benefits, such as mineral oil, aloe vera extract, vitamin E, silicone, and general detergents, may also be incorporated into the finished product.

[0059] Other examples of such materials include, but are not limited to, odor control agents such as odor absorbers, activated carbon fibers and granules, baby powder, baking soda, chelating agents, zeolites, fragrances or other odor masking agents, cyclodextrin compounds, and oxidants. Superabsorbent granules may also be used. Additional options include cationic dyes, optical brighteners, moisturizers, and emollients.

[0060] Go to Figure 2 Once in storage tank 12 ( Figure 1 The foamed fiber suspension is formed in the fiber web forming system 10, and then the foamed fiber suspension can be supplied to the fiber web forming system 10. For example Figure 2 As shown, the fiber web forming system 10 may include one or more forming zones. Figure 2 In one example implementation, three forming regions are shown, including a first forming region 50, a second forming region 52, and a third forming region 54. Forming regions 50, 52, and 54 are positioned along the porous forming surface 26. In one example implementation, as... Figure 2As shown, the porous forming surface 26 can be inclined relative to a horizontal plane. For example, the porous forming surface 26 can be oriented at an angle greater than about ten degrees (10°), such as greater than about twenty degrees (20°), such as greater than about thirty degrees (30°), and generally less than about sixty degrees (60°), such as less than about fifty degrees (50°), relative to the horizontal plane. Each forming region 50, 52, and 54 can be configured to receive a separate and independent flow of foamed fiber suspension for depositing the foamed fiber suspension onto the forming surface 26. For example, the first forming region 50 can deposit the foamed fiber suspension directly onto the forming surface 26. However, the second forming region 52 can be configured to deposit a second flow of foamed fiber suspension on top of the fibers deposited by the first forming region 50. Similarly, the third forming region 54 can deposit a flow of aqueous fiber suspension on top of the fibers deposited by the first forming region 50 and the second forming region 52. In this way, a multilayer fiber web can be formed. However, it should be understood that the systems and processes disclosed herein may include only a single forming zone for forming a single-layer fiber web.

[0061] like Figure 2 As shown, each forming zone 50, 52, and 54 may be in fluid communication with a separate and independent foam fiber supply line. For example, the first forming zone 50 may be in fluid communication with a first foam fiber supply line 56, the second forming zone 52 may be in fluid communication with a second foam fiber supply line 58, and the third forming zone 54 may be in fluid communication with a third foam fiber supply line 60. The first supply line 56, the second supply line 58, and the third supply line 60 may be configured to supply the foam fiber suspension to their respective forming zones 50, 52, and 54 with defined and selected flow characteristics, such as flow rate (e.g., volumetric flow rate), pressure, air content, and / or density. In this respect, as... Figure 1 As shown, each of the supply lines 56, 58, and 60 may be in fluid communication with the mixing reservoir 12. For example, the first supply line 56 may include a first injection line 62 connected to the mixing reservoir 12. Similarly, the second supply line 58 may include a second injection line 64, and the third supply line 60 may be in communication with a third injection line 66. Injection lines 62, 64, and 66 may all be in communication with the mixing reservoir 12 for supplying the foamed fiber suspension to each of the forming zones 50, 52, and 54. Alternatively, the system 10 may include separate mixing reservoirs, and each of the first injection line 62, the second injection line 64, and the third injection line 66 may be connected to a different corresponding mixing reservoir for supplying the foamed fiber suspension to the fiber web forming system 10.

[0062] As shown in the figure, each of the foamed fiber supply lines 56, 58, and 60 may include a pumping device, a flow meter (such as a volumetric flow meter), a pressure monitoring device, and / or a temperature monitoring device. Each foamed fiber supply line 56, 58, and 60 may also be connected to a density monitoring device. For example, the density monitoring device may be part of one of other devices, such as a flow meter. Alternatively, information received from other instruments may be used to calculate the density of the foamed fiber suspension.

[0063] For example, the first foamed fiber supply line may include a first pumping device 68, a first flow meter 74, a first pressure monitoring device 80, and a first temperature monitoring device 81; the second foamed fiber supply line 58 may include a second pumping device 70, a second flow meter 76, a second pressure monitoring device 82, and a second temperature monitoring device 83; and the third foamed fiber supply line 60 may include a third pumping device 72, a third flow meter 78, a third pressure monitoring device 84, and a third temperature monitoring device 85. The pumping devices 68, 70, and 72 may be adjustable, allowing the foamed fiber suspension to be supplied independently to each forming zone 50, 52, and 54 at a desired, selected flow rate and / or pressure. The flow meters 74, 76, and 78, the pressure monitoring devices 80, 82, and 84 (e.g., volumetric flow rate), and the temperature monitoring devices 81, 83, and 85 may monitor the flow rate, pressure, and temperature upstream of the forming surface to calculate at least one characteristic of the flow of the foamed fiber suspension at the forming surface.

[0064] In one example implementation, flow meters 74, 76, and 78, pressure monitoring devices 80, 82, and 84, and temperature monitoring devices 81, 83, and 85 may be positioned to communicate with one or more controllers. The controllers may include a microprocessor or any suitable programmable device. Pumping devices 68, 70, and 72 may also be positioned to communicate with one or more controllers. The controllers may be configured to regulate pumping devices 68, 70, and 72 based on information received from flow meters 74, 76, and 78, from pressure monitoring devices 80, 82, and 84, and / or from temperature monitoring devices 81, 83, and 85. In this way, the flow rate and / or pressure within the set point are expected to supply the foamed fiber suspension to each forming zone 50, 52, and 54 to optimize the forming of the fiber web on the forming surface 26.

[0065] Information received from flow meters 74, 76, and 78, from pressure monitoring devices 80, 82, and 84, and / or from temperature monitoring devices 81, 83, and 85 can be used to determine the characteristics of the foamed fiber suspension at the measurement location. Furthermore, the density of the foamed fiber suspension can be measured or calculated based on information received from various instruments. In one embodiment, this information can be sent to a controller, which is then used to calculate at least one characteristic of the foamed fiber suspension at the forming surface. Specifically, the controller can be programmed to correct for the determined volumetric flow rate at the forming surface based on changes in density, pressure, and temperature. For example, the foamed suspension may experience a pressure drop as it exits the supply line onto the forming surface, which alters the density of the foamed suspension. For example, a method for calculating downstream values ​​of a foamed suspension is disclosed in U.S. Patent No. 4,764,253, which is incorporated herein by reference.

[0066] like Figure 2 As shown, a first discharge device 86, fluidly connected to a first discharge line 92, may be located opposite the first forming region 50 along the forming surface 26. A second discharge device 88, fluidly connected to a second discharge line 94, may be located opposite the second forming region 52. Similarly, a third discharge device 90, connected to a third discharge line 96, may be located opposite the third forming region 54. The first forming region 50, the second forming region 52, and the third forming region 54 may be adjacent to each other along the forming surface 26 and may be positioned on one side of the forming surface 26. Discharge devices 86, 88, and 90 may also be adjacent to each other and may be positioned on opposite sides of the forming surface 26, aligned with the forming regions 50, 52, and 54. When the foamed fiber suspension is deposited from each forming region 50, 52, and 54 onto the forming surface, a fiber web 14 can be formed, and excess fluid may enter the corresponding discharge devices 86, 88, and 90. The discharge devices may be any suitable static or dynamic discharge devices capable of discharging fluid from the fiber web or from the forming surface. The discharge device can be a static suction or a vacuum chamber. Alternatively, the discharge device can be a rotary drum, such as a rotating drum that applies suction.

[0067] like Figure 2As shown, each discharge line 92, 94, and 96 may include a corresponding flow control device, flow meter, temperature monitoring device, and pressure monitoring device. For example, the first discharge line 92 may include a first flow control device 98, a first flow meter 104, a first temperature monitoring device 105, and a first pressure monitoring device 110; the second discharge line 94 may include a second flow control device 100, a second flow meter 106, a second temperature monitoring device 107, and a second pressure monitoring device 112; and the third discharge line 96 may include a third flow control device 102, a third flow meter 108, a third temperature monitoring device 109, and a third pressure monitoring device 114. The flow control devices 98, 100, and 102 may be any suitable device for controlling the flow rate through the lines and may be adjustable valves or pumps. For example, a pump may be used to apply suction to a shaped surface. Alternatively, discharge may be carried out by gravity. In yet another example embodiment, each flow control device 98, 100, and 102 may be a combination of a pump and an adjustable valve.

[0068] In one example implementation, system 10 may also include one or more controllers 116. Controller 116 may include a microprocessor or any suitable programmable device. Figure 2 As shown, each flow control device 98, 100, and 102, each flow meter 104, 106, and 108, each temperature monitoring device 105, 107, and 109, each density monitoring device, and / or each pressure monitoring device 110, 112, and 114 can communicate with the controller 116. The controller 116 can receive information from the flow meters 104, 106, and 108, the temperature monitoring devices 105, 107, and 109, the optional density monitoring devices, and / or the pressure monitoring devices 110, 112, and 114 to regulate the flow control devices 98, 100, and 102, thereby controlling the flow rate of fluid discharged from each of the discharge devices 86, 88, and 90. Information received from flow control devices 98, 100, and 102 (which may be volumetric flow meters), pressure monitoring devices 110, 112, and 114, temperature monitoring devices 105, 107, and 109, and / or optional density monitoring devices can be used to quantify the discharge flow rate of a fluid comprising both gas and liquid. In one example embodiment, controller 116 may use the aforementioned information to calculate the flow rate at the forming surface, such as volumetric flow rate, and control the volumetric flow rate based on at least one characteristic of the foamed suspension supplied to the forming surface. Controller 116 may then control flow control devices 98, 100, and 102 to achieve the calculated discharge flow rate through each discharge device and discharge line.

[0069] In example embodiments, the process and system of this disclosure may further include a sealing region 120 positioned along the shaped fabric 26 and in fluid communication with a sealing fluid supply line 122. For example... Figure 2 As shown, the sealing fluid supply line 122 may include a pumping device 124, a flow meter 126, a pressure monitoring device 128, and a temperature monitoring device 129. The sealing fluid supply line 122 is used to supply fluid (particularly a liquid) to the sealing zone 120. The sealing fluid can be any suitable liquid. For example, the sealing fluid can be water, water, and surfactant solutions, etc. In one example embodiment, the sealing fluid can be non-fibrous. The sealing fluid can be supplied to the sealing fluid zone 120 at a certain flow rate and / or pressure, such that the sealing fluid deposited on the forming surface 26 forms a fluid seal that prevents air from flowing in the upstream longitudinal direction. Information received from the flow meter 126, the pressure monitoring device 128, the temperature monitoring device 129, and the optional density monitoring device can be used to calculate the volumetric flow rate of the foam at the forming surface.

[0070] like Figure 2 As shown, the sealing region 120 can be positioned upstream and adjacent to multiple forming regions. The sealing region 120 can also be positioned opposite to a sealing discharge device 130 connected to a sealing discharge line 132. The sealing discharge line 132 may include a flow control device 134, a flow meter 136, a temperature monitoring device 137, and a pressure sensing device 138, all of which can communicate with a controller 116. In this way, the discharge flow rate of the sealing fluid can be controlled based on the flow rate or pressure of the sealing fluid entering or leaving the sealing region 120. By including the sealing region 120, better formation of the fiber web 14 occurs opposite to the first forming region 50.

[0071] like Figure 2 The illustrated web forming system 10 may further include a suction zone 140 adjacent to and located downstream of a plurality of forming zones. The suction zone 140 may be in fluid communication with a discharge line 142, which may include a pressure monitoring device 144. The suction zone 140 is used to suction fluid through the preformed web 14 after the web has been formed. The suction zone 140 is used to remove excess fluid, particularly liquids, from the web 14. In one aspect, the discharge flow rate of the foamed fiber suspension discharged through one or more discharge devices may be controlled, allowing excess fluid from one or more forming zones to enter the suction zone 140. Ideally, the suction zone 140 facilitates the discharge of fluid from the web 14 without causing any harmful effects.

[0072] like Figure 2As shown, all discharge lines 92, 94, 96, 132, and 142 can supply gas to the separation tank 150. The separation tank 150 can be configured to separate free gas from foam. As shown, the separation tank 150 may include a gas outlet 152 and a liquid outlet 154, the gas outlet being connectable to a vacuum source. The liquid collected in the separation tank 150 may include a mixture of water and surfactants. Figure 2 As shown, pumping device 156 can be used to pump liquid from separation tank 150 to liquid tank 158, which can also be positioned in communication with water source 160. Liquid tank 158 can be used to recycle the water and surfactant mixture back into the process via supply lines 56, 58, 60 and 122.

[0073] Return to reference Figure 1 After the fiber web 14 is formed from the fiber web forming system or headbox 10, the fiber web 14 can be supplied to various downstream processes. Figure 1 This is just one example embodiment of the process for drying the fiber web 14 after forming. As shown, the fiber web 14 is formed on the forming surface 26 and conveyed downstream. For example, the annularly traveling formed fabric 26 may be supported and driven by rollers 28.

[0074] Once formed on the shaped fabric 26, the formed fiber web 14 can have a consistency of less than about fifty percent (50%), such as less than about twenty percent (20%), such as less than about ten percent (10%), such as less than about five percent (5%). In fact, the forming consistency can be less than about two percent (2%), such as less than about one hundred and eight percent (1.8%), such as less than about one hundred and fifty percent (1.5%). The forming consistency is typically greater than about half a percent (0.5%), such as greater than about one hundred and eight percent (0.8%).

[0075] Once the wet fiber web 14 is formed on the shaped fabric 26, the fiber web 14 is conveyed downstream and optionally further dehydrated. For example, the process may optionally include multiple vacuum devices 16, such as vacuum chambers and vacuum rollers. Vacuum chambers help remove moisture from the newly formed fiber web 14.

[0076] like Figure 1As shown, the formed fabric 26 can also communicate with a steam box 18 positioned above a pair of vacuum rollers 20. For example, the steam box 18 can increase dryness and reduce transverse moisture variance. Steam applied from the steam box 18 heats the moisture in the wet web 14, making it easier for water to drain from the web, especially when combined with the vacuum rollers 20. The newly formed web 14 is conveyed downstream from the formed fabric 26 and dried. Any suitable drying device can be used to dry the web 14. For example, the web 14 can be air-dried or placed on a heated drying drum and wrinkled or left wrinkle-free. For example, in Figure 1 In this process, the formed fiber web 14 is placed in contact with two heated drying drums 38 and 40. In one example embodiment, the fiber web 14 can be supplied from the drying drums 38 and 40 to a ventilated dryer before being wound into a roll.

[0077] Figure 2 The embodiments described herein are used to form multilayer fiber webs. In another aspect, the process disclosed herein can be used to produce single-layer fiber webs from a foamed material suspension.

[0078] Now go to Figure 3 , Figure 4 and Figure 5 This illustration shows a system 200 for measuring foam density in a foam forming system according to an example embodiment of the present disclosure. It should be understood that system 200 can be used in or with any foam forming system or process for forming a fiber web from a foamed fiber suspension. For example, system 200 can be used in... Figure 1 and Figure 2 The system 200 may be used in or with the example systems and processes shown and described above. However, it should be understood that in alternative example embodiments, the system 200 may be used in or with other systems and processes for forming fiber webs from foamed fiber suspensions.

[0079] like Figure 3 As shown, system 200 includes a housing 210, a weir 220, a pressure measuring conduit 230, and a pressure sensor 250. Housing 210 includes an inlet 211 for foam to enter housing 210 and an outlet 213 for foam to exit housing 210. For example, from fiber web forming system 10 ( Figure 1 and Figure 2 The foam can flow into the interior 212 of the housing 210 through the inlet 211 and out of the interior 212 of the housing 210 through the outlet 213. As can be seen from the above, the system 200 can take a portion of the pressurized flow of foam within the fiber web forming system 10 for testing the density of the foam, as discussed in more detail below.

[0080] In an example embodiment, the housing 210 may include various walls for forming the housing 210, the housing having an interior 212 for foam therein. Figures 3 to 5 In the example embodiment shown, the housing 210 may be generally cubic or rectangular prism. In other example embodiments, the housing 210 may be cylindrical or have other shapes, depending on the desired arrangement. The interior 212 of the housing 210 may be adjacent to the ambient atmosphere. For example, the top portion 218 of the housing 210 may be open, such that the interior 212 of the housing 210 is adjacent to the ambient atmosphere through the top portion 218 of the housing 210. As can be seen from the above, it is permissible for the foam within the housing 210 to reach atmospheric pressure.

[0081] A weir 220 is disposed within the housing 210. For example, the weir 220 may be disposed within the interior 212 of the housing 210, such that the weir 220 separates the interior 212 of the housing 210 into an inlet portion 214 and an outlet portion 216 of the housing 210. An inlet 211 of the housing 210 may be located at or near the inlet portion 214 of the interior 212. Foam may flow into the inlet portion 214 of the interior 212 via the inlet 211 of the housing 210. In some example embodiments, the inlet 211 of the housing 210 may be located at or near the bottom of the inlet portion 214 of the interior 212. An outlet 213 of the housing 210 may be located at the outlet portion 216 of the interior 212. Foam may flow out of the outlet portion 216 of the interior 212 via the outlet 213 of the housing 210. In some example embodiments, the outlet 213 of the housing 210 may be located at or near the bottom of the outlet portion 216 of the interior 212. As can be seen from the above, the inlet 211 and outlet 213 of the shell 210 can be positioned relative to each other around the weir 220.

[0082] The weir 220 may be configured such that foam in the interior 212 of the housing 210 flows through the weir 220 between the inlet portion 214 and the outlet portion 216 of the interior 212. For example, foam in the inlet portion 214 of the interior 212 may flow through the head 222 of the weir 220 into the outlet portion 216 of the interior 212. The head 222 of the weir 220 may correspond to the lowest portion of the weir 220 where foam may flow from the inlet portion 214 into the outlet portion 216 of the interior 212. In the illustrated example embodiment, the head 222 of the weir 220 may be linear. In other example embodiments, the head 222 of the weir 220 may have a curved shape, a piano key or maze shape, a triangular shape, or other shapes, depending on the desired arrangement. The weir 220 may include a wall facing the inlet portion 214 of the interior 212 and a wall facing the outlet portion 216 of the interior 212. The wall of the inlet portion 214 of the weir 220 facing inward 212 can have a greater slope than the wall of the outlet portion 216 of the weir 220 facing inward 212.

[0083] The weir 220 can advantageously control the foam level at the inlet portion 214 of the interior 212, for example, without requiring large height changes to provide significant variations in flow rate. Thus, the weir 220 can advantageously help convert the variable inlet flow rate from the fiber web forming system 10 into a nominally constant head pressure for measuring foam density. For example, foam enters the inlet portion 214 of the interior 212 from the inlet 211 of the housing 210. As the foam fills the inlet portion 214 of the interior 212, it can overflow the weir 220 into the outlet portion 216 of the interior 212, which collects the foam at the outlet 213 of the housing 210. The foam filling the inlet portion 214 of the interior 212 can generate a constant head pressure in the pressure measuring conduit 230, which is measured to determine the foam density, as described in more detail below. Therefore, the weir 220 can advantageously help reduce or eliminate the variability in pressure-based foam density measurements due to head pressure variations caused by variable flow.

[0084] The pressure measuring conduit 230 includes an inlet 232 positioned to receive foam from an inlet portion 214 of the interior 212 and an outlet 236 for foam from the pressure measuring conduit 230. The inlet 232 of the pressure measuring conduit 230 may be positioned above the outlet 236. This relative positioning between the inlet 232 and outlet 236 of the pressure measuring conduit 230 can create a head difference that allows foam to flow from the inlet portion 214 of the interior 212 into the pressure measuring conduit 230 when the foam fills the inlet portion 214. Therefore, foam from the inlet portion 214 of the interior 212 can enter the pressure measuring conduit 230 at the inlet 232 and flow through the pressure measuring conduit 230 to the outlet 236. The pressure measuring conduit 230 can therefore receive foam from the inlet portion 214 of the interior 212 for measurement by the pressure sensor 250, and the outlet 236 of the pressure measuring conduit 230 can guide excess foam out of the pressure measuring conduit 230. In the example embodiment, the controlled flow of foam through the pressure measuring conduit 230 can advantageously help reduce or eliminate the variability in pressure-based foam density measurements caused by head pressure variations due to variable flow.

[0085] In an example embodiment, the inlet 232 of the pressure measuring conduit 230 may be positioned at the inlet portion 214 of the interior 212 above the inlet 211 of the housing 210. For example... Figure 4 and Figure 5 As shown, in some example embodiments, the inlet 232 of the pressure measuring conduit 230 may be positioned on the weir 220 below the head 222 of the weir 220. As an example, the inlet 232 of the pressure measuring conduit 230 may be positioned at a distance of not less than five centimeters (5 cm), such as not less than ten centimeters (10 cm), such as not less than fifteen centimeters (15 cm) from the head 222 of the weir 220. As another example, the inlet 232 of the pressure measuring conduit 230 may be positioned at a distance of not more than fifty centimeters (50 cm), such as not more than forty centimeters (40 cm), such as not more than thirty centimeters (30 cm) from the head 222 of the weir 220.

[0086] The interior 242 of the pressure measuring conduit 230 may be adjacent to the ambient atmosphere. For example, the pressure measuring conduit 230 may include a discharge opening 240. The discharge opening 240 may be located between the inlet 232 and the outlet 236 of the pressure measuring conduit 230. For example, the discharge opening 240 may be located near the inlet 232 of the pressure measuring conduit 230 on a branch line from the pressure measuring conduit 230. In an example embodiment, the discharge opening 240 may be located below the inlet 232 of the pressure measuring conduit 230 and above the outlet 236 of the pressure measuring conduit 230. The discharge opening 240 may include an opening to the ambient atmosphere. Therefore, the discharge opening 240 may limit or prevent foam from being siphoned from the inlet portion 214 of the interior 212.

[0087] In an example implementation, the outlet 236 of the pressure measuring conduit 230 can be configured to guide foam from the pressure measuring conduit 230 into a tank, such as separator tank 150. Figure 2 The outlet 213 of the housing 210 can also be configured to guide foam from the outlet portion 216 of the housing 210 into a container, such as a separator container 150. Thus, for example, both the outlet 236 of the pressure measuring conduit 230 and the outlet 213 of the housing 210 can be positioned and oriented to guide foam into the same container. For example, both the outlet 236 of the pressure measuring conduit 230 and the outlet 213 of the housing 210 can be positioned above the separator container 150, such that foam falls from outlets 213, 236 into the separator container 150. Therefore, a portion of the pressurized flow of foam removed by the system 200 for testing foam density within the web forming system 10 can be recombined into the pressurized flow of foam downstream of the system 200.

[0088] As described above, the outlet 236 of the pressure measuring conduit 230 can be located below the inlet 232 of the pressure measuring conduit 230. As an example, the outlet 236 of the pressure measuring conduit 230 can be located not less than two centimeters (2cm) below the inlet 232 of the pressure measuring conduit 230, such as not less than five centimeters (5cm), such as not less than seven centimeters (7cm). As another example, the outlet 236 of the pressure measuring conduit 230 can be located not more than forty centimeters (40cm) below the inlet 232 of the pressure measuring conduit 230.2, such as not more than twenty centimeters (20cm), such as not more than fifteen centimeters (15cm), such as not more than ten centimeters (10cm).

[0089] In an example embodiment, the outlet 236 of the pressure measuring conduit 230 may be adjustable, such that the vertical distance between the inlet 232 and the outlet 236 of the pressure measuring conduit 230 is adjustable. For example, the pressure measuring conduit 230 may be rotatable to adjust the vertical distance between the inlet 232 and the outlet 236. As another example, a sleeve may be mounted on the pressure measuring conduit 230 at the outlet 236 to adjust the vertical distance between the inlet 232 and the outlet 236 of the pressure measuring conduit 230. Adjusting the vertical distance between the inlet 232 and the outlet 236 of the pressure measuring conduit 230 can advantageously help to change the flow rate of foam through the pressure measuring conduit 230. Thus, for example, the flow rate of foam through the pressure measuring conduit 230 can be controlled to a selected speed to reduce or eliminate variations in pressure-based foam density measurements.

[0090] The pressure sensor 250 can be configured to measure the pressure of foam in the pressure measuring conduit 230. For example, the pressure sensor 250 can be configured to measure the pressure of foam at measurement position 234 in the pressure measuring conduit 230. Allowing foam to flow through the pressure measuring conduit 230 while the pressure sensor 250 can measure the pressure of foam in the pressure measuring conduit 230 can advantageously maintain the stability of the foam during measurement.

[0091] The measuring position 234 can be configured below the inlet 232 and outlet 236 of the pressure measuring conduit 230. As an example, the measuring position 234 can be located at or near the lowest part of the pressure measuring conduit 230. Figure 3 As shown, at least a portion of the pressure measuring conduit 230 may be U-shaped between its inlet 232 and outlet 236. For example, the pressure measuring conduit 230 may include a U-shaped section 235 between its inlet 232 and outlet 236. The measurement position 234 may be located at or near the lowermost portion of the U-shaped section 235.

[0092] The pressure measuring conduit 230 may also include a drain tap 238. Foam and other fluids can be removed from the pressure measuring conduit 230 through the drain tap 238. The drain tap 238 may be located at or near the lowest portion of the pressure measuring conduit 230. For example, the drain tap 238 may be located at or near the lowest portion of the U-shaped section 235.

[0093] like Figure 3As shown, system 200 may also include a processing device or controller 260, or be operatively communicable to such processing device or controller, which is typically configured to facilitate the operation of at least a portion of system 200. In this regard, pressure sensor 250 and other components of system 200 may communicate with controller 260. Thus, for example, controller 260 may receive input from pressure sensor 250 and may determine the density of foam in pressure measuring conduit 230 based at least in part on input from pressure measuring conduit 230. Pressure sensor 250 and other components of system 200 may communicate with controller 260 via, for example, one or more signal lines or a shared communication bus. In this way, input / output (“I / O”) signals can be routed between controller 260 and various operating components of system 200.

[0094] As used herein, the terms “processing device,” “computing device,” or “controller” can generally refer to any suitable processing device, such as a general-purpose or special-purpose microprocessor, microcontroller, integrated circuit, application-specific integrated circuit (ASIC), digital signal processor (DSP), field-programmable gate array (FPGA), logic device, one or more central processing units (CPU), graphics processing units (GPUs), processing units performing other special-purpose computing, semiconductor devices, etc. Furthermore, these “controllers” are not necessarily limited to a single element but can include any suitable number, type, and configuration of processing devices integrated in any suitable manner to facilitate appliance operation. Alternatively, controller 260 may be constructed without using a microprocessor, for example, by using a combination of discrete analog and / or digital logic circuits (such as switches, amplifiers, integrators, comparators, flip-flops, and AND / OR gates) to perform control functions, rather than relying on software.

[0095] The controller 260 may include or be associated with one or more memory elements or non-transitory computer-readable storage media (such as RAM, ROM, EEPROM, EPROM, flash memory devices, disks, or other suitable memory devices, including combinations thereof). These memory devices may be components separate from the processor or may be included or integrated within the processor. Furthermore, these memory devices may store information and / or data accessible by one or more processors, including instructions executable by one or more processors. It should be understood that the instructions may be software written in any suitable programming language or may be implemented in hardware. Additionally or alternatively, the instructions may be executed logically and / or virtually using separate threads on one or more processors.

[0096] For example, controller 260 may be operable to execute programming instructions or microcontroller code associated with the operation of system 200. In this regard, the instructions may be software or any set of instructions that, when executed by a processing device, causes the processing device to perform operations such as running one or more software applications, measuring foam density via signals from pressure sensor 250, etc. Furthermore, it should be noted that controller 260, as disclosed herein, is capable of and can be operated to perform any methods, method steps, or portions of methods disclosed herein. For example, in some example embodiments, the methods disclosed herein may be embodied in programming instructions stored in memory and executed by controller 260.

[0097] The memory device may also store data that can be retrieved, manipulated, created, or stored by one or more processors or portions of the controller 260. The data may include, for example, data that facilitates the execution of the methods described herein. The data may be stored locally (e.g., on the controller 260) in one or more databases and / or may be split, such that the data is stored in multiple locations. Additionally or alternatively, one or more databases may be connected to the controller 260 via any suitable network, such as a high-bandwidth local area network (LAN) or wide area network (WAN). In this regard, for example, the controller 260 may also include a communication module or interface that can be used, for example, to communicate with one or more other components of the system 200, the controller 260, or any other suitable device via any suitable communication line or network and using any suitable communication protocol. The communication interface may include any suitable component for interfacing with one or more networks, including, for example, a transmitter, receiver, port, controller, antenna, or other suitable component.

[0098] As described above, the controller 260 can be configured to receive data from the pressure sensor 250. The data from the pressure sensor 250 can correspond to the pressure measurement of the foam in the pressure measuring conduit 230 at the measuring position 234. Furthermore, the pressure sensor 250 can measure the head pressure generated by the foam below the inlet 232 and outlet 236 of the pressure measuring conduit 230, and the pressure sensor 250 can output the data corresponding to the pressure measurement to the controller 260.

[0099] The controller 260 can also calculate the density of the foam in the pressure measuring conduit 230 based at least in part on pressure measurements from the pressure sensor 250. For example, the density of the foam in the pressure measuring conduit 230 can be proportional to the pressure of the foam in the pressure measuring conduit 230. To calibrate the density measurement via pressure measurements from the pressure sensor 250, water can flow through the pressure measuring conduit 230, and pressure measurements from the pressure sensor 250 can be obtained. Due to the known density of water, the pressure measurements taken by the pressure sensor 250 when water flows through the pressure measuring conduit 230 can therefore correspond to a first calibration point. Next, foam (e.g., the lowest density foam that will pass through the system 200) can flow through the pressure measuring conduit 230, and pressure measurements from the pressure sensor 250 can be obtained. The density of the foam can be determined via manual density measurement, such as by weighing a fixed volume of foam to calculate the foam density, to provide a second calibration point. Linear interpolation of the first and second calibration points can be used to calculate the foam density corresponding to other pressure measurements from the pressure sensor 250 during operation of the system 200.

[0100] As can be seen from the above, system 200 can advantageously measure the pressure of the supplemental flow of foam. Therefore, for example, system 200 can accurately measure the density of foam flowing through system 200 with a high air content (such as an air content close to 65%). Furthermore, system 200 can be vertically compact, for example, such that the total height of system 200 is less than 1.5 meters (1.5 m), such as less than 1.2 meters (1.2 m). System 200 can also have high resolution. For example, system 200 can be accurate to a density of less than 2 percent, where the feed flow control ratio exceeds 100:1. In general, system 200 can provide a low-cost, proven mechanism for density measurement within a foam forming system. System 200 may include various features for reducing or preventing variations in foam density measurement due to variable inlet flow rates and foam decomposition.

[0101] These and other modifications and variations of the invention can be practiced by those skilled in the art without departing from the spirit and scope of the invention, which are more specifically set forth in the appended claims. Furthermore, it should be understood that aspects of the various embodiments are interchangeable in whole or in part. Moreover, those skilled in the art will understand that the foregoing description is merely illustrative and is not intended to limit the invention further described in the appended claims.

[0102] Example Implementation Plan

[0103] First Example Implementation: A density measurement component for a foam forming system, the foam forming system comprising: a housing including an inlet for foam to enter the housing and an outlet for foam to exit the housing, the interior of the housing being adjacent to the ambient atmosphere; a weir disposed within the housing such that the weir separates the interior of the housing into an inlet portion and an outlet portion, the inlet of the housing being positioned at the inlet portion of the interior, such that foam from the inlet flows into the inlet portion of the interior, and the outlet of the housing being positioned at the outlet portion of the interior. The weir is configured such that the foam from the outlet portion of the interior flows into the outlet of the housing, and the weir is configured such that the foam in the interior of the housing flows through the weir between the inlet portion and the outlet portion of the interior; a pressure measuring conduit includes an inlet positioned for receiving the foam from the inlet portion of the interior and an outlet for the foam from the pressure measuring conduit; and a pressure sensor configured to measure the pressure of the foam in the pressure measuring conduit at a measuring position located below the inlet and the outlet of the pressure measuring conduit.

[0104] Second example implementation: The density measuring assembly according to the first example implementation, wherein the inlet of the pressure measuring conduit is positioned above the outlet of the pressure measuring conduit.

[0105] Third example implementation: According to the density measuring assembly of the first example implementation or the second example implementation, the outlet of the pressure measuring conduit is adjustable such that the vertical distance between the inlet and the outlet of the pressure measuring conduit is adjustable.

[0106] Fourth example implementation: The density measuring assembly according to any one of the first to third example implementations, wherein the interior of the pressure measuring conduit is adjacent to the ambient atmosphere.

[0107] Fifth example implementation: The density measuring assembly according to any one of the first to fourth example implementations, wherein the pressure measuring conduit further includes a discharge opening positioned above the outlet of the pressure measuring conduit.

[0108] Sixth Example Implementation: A density measuring assembly according to any one of the first to fifth example implementations, wherein the inlet of the pressure measuring conduit is positioned on the weir below the head of the weir.

[0109] Seventh Example Implementation: A density measuring assembly according to any one of the first to sixth example implementations, wherein at least a portion of the pressure measuring conduit is U-shaped between the inlet and the outlet of the pressure measuring conduit.

[0110] Eighth Example Implementation: A density measuring assembly according to any one of the first to seventh example implementations, wherein the measuring position is set near the bottom of the U-shaped portion of the pressure measuring conduit.

[0111] Ninth Example Implementation: The density measuring assembly according to any one of the first to eighth example implementations, wherein the pressure measuring conduit further includes a discharge tap disposed near the bottom of the U-shaped portion of the pressure measuring conduit.

[0112] Tenth Example Implementation: The density measuring component according to any one of the first to ninth example implementations further includes a controller in signal communication with the pressure sensor, the controller being configured to: receive data corresponding to a pressure measurement from the pressure sensor; and calculate the density of the foam in the pressure measuring conduit based at least in part on the pressure measurement.

[0113] Eleventh Example Implementation: A density measuring assembly according to any one of the first to tenth example implementations, wherein the outlet of the housing and the outlet of the pressure measuring conduit are configured to guide foam into a can.

[0114] Twelfth Example Implementation: A foam forming system comprising: a headbox; and a density measuring assembly configured to measure the density of foam in the headbox, the density measuring assembly including a housing having an inlet and an outlet for the foam, the interior of the housing being adjacent to the ambient atmosphere; a weir disposed within the housing, the weir being configured such that the foam in the interior of the housing flows through the weir between the inlet and the outlet of the housing; a pressure measuring conduit including an inlet for receiving the foam from the interior of the housing, the inlet of the pressure measuring conduit being located at an inlet side of the housing; and a pressure sensor configured to measure the pressure of the foam in the pressure measuring conduit at a measuring position located below the inlet of the pressure measuring conduit.

[0115] Thirteenth Example Implementation: The foam forming system according to the twelfth example implementation, wherein the inlet of the pressure measuring conduit is positioned above the outlet of the pressure measuring conduit.

[0116] Fourteenth Example Implementation: The foam forming system according to the twelfth or thirteenth example implementation, wherein the outlet of the pressure measuring conduit is adjustable such that the vertical distance between the inlet and the outlet of the pressure measuring conduit is adjustable.

[0117] Fifteenth Example Implementation: A foam forming system according to any one of the twelfth to fourteenth example implementations, wherein the interior of the pressure measuring conduit is adjacent to the ambient atmosphere.

[0118] Sixteenth Example Implementation: A foam forming system according to any one of the twelfth to fifteenth example implementations, wherein the pressure measuring conduit further includes a discharge opening positioned above the outlet of the pressure measuring conduit.

[0119] Seventeenth Example Implementation: A foam forming system according to any one of the twelfth to sixteenth example implementations, wherein the inlet of the pressure measuring conduit is positioned on the weir below the head of the weir.

[0120] Eighteenth Example Implementation: A foam forming system according to any one of the twelve to seventeenth example implementations, wherein at least a portion of the pressure measuring conduit is U-shaped between the inlet and the outlet of the pressure measuring conduit.

[0121] Nineteenth Example Implementation: A foam forming system according to any one of the twelve to eighteenth example implementations, wherein the measuring position is set near the bottom of the U-shaped portion of the pressure measuring conduit.

[0122] Twentieth Example Implementation: A foam forming system according to any one of the twelfth to nineteenth example implementations, wherein the pressure measuring conduit further includes a discharge tap, the discharge tap being disposed near the bottom of the U-shaped portion of the pressure measuring conduit.

[0123] Twenty-first example implementation: The foam forming system according to any one of the twelfth to twentieth example implementations further includes a controller in communication with the pressure sensor signal, the controller being configured to: receive data corresponding to a pressure measurement from the pressure sensor; and calculate the density of the foam in the pressure measuring conduit based at least in part on the pressure measurement.

[0124] Twenty-second example implementation: The foam forming system according to any one of the twelfth to twenty-first example implementations further includes a tank, wherein the outlet of the housing and the outlet of the pressure measuring conduit are arranged for guiding the foam into the tank.

[0125] Example Implementation 23: A method for measuring foam density within a foam forming process, substantially as described herein.

[0126] Example Implementation 24: A system for measuring foam density within a foam forming process, substantially as described herein.

Claims

1. A density measuring component for a foam forming system, the density measuring component comprising: A housing, the housing including an inlet for foam to enter the housing and an outlet for foam to exit the housing, the interior of the housing being adjacent to the ambient atmosphere; A weir is disposed within the housing such that it separates the interior of the housing into an inlet portion and an outlet portion of the housing, the inlet of the housing being positioned at the inlet portion of the interior such that foam from the inlet flows into the inlet portion of the interior, and the outlet of the housing being positioned at the outlet portion of the interior such that foam from the outlet portion of the interior flows into the outlet portion of the housing, the weir being configured such that foam in the interior of the housing flows through the weir between the inlet portion and the outlet portion of the interior; A pressure measuring conduit, the pressure measuring conduit including an inlet positioned for receiving foam from the inlet portion of the interior and an outlet for the foam from the pressure measuring conduit; as well as A pressure sensor configured to measure the pressure of the foam in the pressure measuring conduit at a measuring location located below the inlet and outlet of the pressure measuring conduit.

2. The density measuring assembly of claim 1, wherein the inlet of the pressure measuring conduit is positioned above the outlet of the pressure measuring conduit.

3. The density measuring assembly according to claim 1, wherein the outlet of the pressure measuring conduit is adjustable such that the vertical distance between the inlet and the outlet of the pressure measuring conduit is adjustable.

4. The density measuring assembly of claim 1, wherein the interior of the pressure measuring conduit is adjacent to the ambient atmosphere.

5. The density measuring assembly of claim 1, wherein the pressure measuring conduit further includes a discharge opening positioned above the outlet of the pressure measuring conduit.

6. The density measuring assembly of claim 1, wherein the inlet of the pressure measuring conduit is positioned on the weir below the head of the weir.

7. The density measuring assembly of claim 1, wherein at least a portion of the pressure measuring conduit is U-shaped between the inlet and the outlet of the pressure measuring conduit.

8. The density measuring assembly of claim 7, wherein the measuring position is configured near the bottom of the U-shaped portion of the pressure measuring conduit.

9. The density measuring assembly of claim 7, wherein the pressure measuring conduit further comprises a discharge tap disposed near the bottom of the U-shaped portion of the pressure measuring conduit.

10. The density measuring assembly of claim 1, further comprising a controller in communication with the pressure sensor signal, the controller being configured to: Receive data corresponding to the pressure measurement from the pressure sensor; and The density of the foam in the pressure measuring conduit is calculated at least in part based on the pressure measurement.

11. The density measuring assembly of claim 1, wherein the outlet of the housing and the outlet of the pressure measuring conduit are configured to guide foam into the tank.

12. A foam forming system, the foam forming system comprising: headbox; as well as A density measuring component, configured to measure the density of foam in the headbox, the density measuring component comprising: A housing, the housing including an inlet and an outlet for the foam, the interior of the housing being adjacent to the ambient atmosphere; A weir, disposed within the housing, is configured such that the foam within the interior of the housing flows through the weir between the inlet and outlet of the housing; A pressure measuring conduit, the pressure measuring conduit including an inlet for receiving foam from the interior of the housing, the inlet of the pressure measuring conduit being located on the inlet side of the housing; as well as A pressure sensor configured to measure the pressure of the foam in the pressure measuring conduit at a measuring location located below the inlet of the pressure measuring conduit.

13. The foam forming system of claim 12, wherein the inlet of the pressure measuring conduit is positioned above the outlet of the pressure measuring conduit.

14. The foam forming system of claim 12, wherein the outlet of the pressure measuring conduit is adjustable such that the vertical distance between the inlet and the outlet of the pressure measuring conduit is adjustable.

15. The foam forming system of claim 12, wherein the interior of the pressure measuring conduit is adjacent to the ambient atmosphere.

16. The foam forming system of claim 12, wherein the pressure measuring conduit further includes a discharge opening positioned above the outlet of the pressure measuring conduit.

17. The foam forming system of claim 12, wherein the inlet of the pressure measuring conduit is positioned on the weir below the head of the weir.

18. The foam forming system of claim 12, wherein at least a portion of the pressure measuring conduit is U-shaped between the inlet and the outlet of the pressure measuring conduit.

19. The foam forming system of claim 18, wherein the measuring position is set near the bottom of the U-shaped portion of the pressure measuring conduit.

20. The foam forming system of claim 18, wherein the pressure measuring conduit further includes a discharge tap, the discharge tap being disposed near the bottom of the U-shaped portion of the pressure measuring conduit.

21. The foam forming system of claim 12, further comprising a controller communicating with the pressure sensor signal, the controller being configured to: Receive data corresponding to the pressure measurement from the pressure sensor; and The density of the foam in the pressure measuring conduit is calculated at least in part based on the pressure measurement.

22. The foam forming system of claim 12, further comprising a tank, wherein the outlet of the housing and the outlet of the pressure measuring conduit are arranged for guiding the foam into the tank.

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