Particle feeder for foam forming

Abstract

A process and system for adding particulate material to a stream of foam into a headbox. A particulate material feeder includes a supply chamber that can be filled with particulate material, a supply hopper, and a gas lock valve disposed between the supply chamber and the supply hopper. When the gas lock valve is open, particulate material in the supply chamber can flow into the supply hopper. A pressure supply line is coupled to the supply chamber and is configured for air to flow into and / or out of the supply chamber.

Description

Cross-reference to related applications

[0001] This application relates to and claims priority to U.S. Provisional Application No. 63 / 601,350, 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 forming systems, superabsorbent materials are added to the foam prior to the headbox. Adding superabsorbent materials to the foam can be challenging. For example, in addition to the superabsorbent material, air may also be entrained into the foam, which can adversely affect the foam's performance in the headbox.

[0005] A system for the improved introduction of superabsorbent materials into foams would be useful. Summary of the Invention

[0006] Generally, this disclosure relates to an improved process and system for adding particulate material to a foam stream leading to a headbox. A pump (such as an ejector) draws particulate material (such as a superabsorbent material) into the foam stream leading to the headbox. To limit air entrainment into the foam by the vacuum generated by the pump, a particulate material feeder assembly positioned upstream of the headbox in the flow path from the foam to the headbox includes an airlock valve between a feed chamber and a feed hopper. When the airlock valve is open, particulate material in the feed chamber can flow from the feed chamber into the feed hopper; and when the airlock valve is closed, it can block airflow between the feed chamber and the feed hopper. Thus, the airlock valve can selectively seal the feed hopper to limit available air in the feed hopper for entrainment into the foam. A pressure supply line, independent of the pump, may also be connected to the feed chamber. The pressure supply line can draw air from the feed chamber and / or supply air to the feed chamber. Therefore, for example, when the supply chamber is filled with granular material and the airlock valve is closed, the pressure supply line can evacuate air from the supply chamber to limit the flow of air from the supply chamber into the supply hopper when the airlock valve opens to transfer the granular material from the supply chamber to the supply hopper. The aforementioned granular material feeder assembly advantageously allows for continuous operation of the foam forming process at the headbox by refilling the supply hopper with granular material, for example, without introducing large amounts of air into the foam.

[0007] In one example embodiment, a foam forming system includes a headbox and a superabsorbent material feeder assembly positioned upstream of the headbox in a flow path for the foam to the headbox. The superabsorbent material feeder assembly is configured to add superabsorbent material to the foam. The superabsorbent material feeder assembly includes a supply chamber capable of being filled with superabsorbent material, a supply hopper, and an airlock valve disposed between the supply chamber and the supply hopper. The airlock valve is configured to open and close to selectively connect the supply chamber and the supply hopper. When the airlock valve is open, superabsorbent material in the supply chamber can flow into the supply hopper. A pressure supply line is coupled to the supply chamber and configured to allow air to flow into and / or out of the supply chamber.

[0008] In another example embodiment, the particulate material feeder for the foam forming system includes a feed chamber capable of being filled with particulate material, a feed hopper positioned below the feed chamber, and an airlock valve disposed between the feed chamber and the feed hopper. The airlock valve is configured to open and close to selectively connect the feed chamber and the feed hopper. When the airlock valve is open, the particulate material in the feed chamber can flow into the feed hopper. A pressure supply line is connected to the feed chamber and configured to allow air to flow into and / or out of the feed chamber.

[0009] In another example implementation, a method for supplying particulate material within a foam forming process includes: flowing superabsorbent material into a supply chamber; removing air from the supply chamber; opening an airlock valve between the supply chamber and a supply hopper to transfer the superabsorbent material from the supply chamber to the supply hopper; and metering the superabsorbent material into a foam stream in a headbox.

[0010] Other features and aspects of this disclosure are discussed in more detail below. Attached Figure Description

[0011] 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:

[0012] 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;

[0013] 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;

[0014] Figure 3 This is a schematic diagram of a system and process for supplying superabsorbent material during foam forming of a nonwoven fiber web, according to an example embodiment of this disclosure; and

[0015] Figure 4 This is a flowchart of a process for supplying superabsorbent material during foam forming of a nonwoven fiber web, according to an example embodiment of the present disclosure.

[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 supplying superabsorbent material or other particulate materials in a foam forming process. To supply superabsorbent material to a foam stream leading to a headbox, a supply hopper supplies the superabsorbent material to a metering device, which in turn supplies the superabsorbent material to the foam stream leading to the headbox. The metering device may be housed within a sealed housing, for example, such that the interior of the metering device containing the superabsorbent material is vacuum-pressurized (by means of a pump (such as an ejector) that injects the superabsorbent material from the metering device into the foam stream leading to the headbox), reducing its pressure to below atmospheric pressure. The interior of the supply chamber supplying the superabsorbent material to the supply hopper may also be vacuum-pressurized to a pressure below atmospheric pressure. Therefore, air can be evacuated from the superabsorbent material supplied to the supply hopper to limit air entrainment from the supply hopper into the foam stream leading to the headbox. Furthermore, an airlock valve may be positioned between the supply chamber and the supply hopper. When the airlock valve is open, it allows superabsorbent material to flow from the supply chamber to the supply hopper; and when the airlock valve is closed, it prevents airflow from the supply chamber into the supply hopper. The supply chamber may be connected to a pressure supply line separate from the pump, which draws air from the superabsorbent material in the supply chamber and / or supplies air to the superabsorbent material in the supply chamber before opening the airlock valve to allow the superabsorbent material to flow from the supply chamber into the supply hopper.

[0042] In some example implementations, a first pressure sensor measures the air pressure in the supply chamber, and a second pressure sensor measures the air pressure in the supply hopper. A controller can be configured to adjust the air pressure in the supply chamber based on measurements from the first and second sensors. For example, the controller can adjust a valve to increase or decrease the flow rate of air entering and / or exiting the supply chamber through the pressure supply line. As another example, the controller can adjust a valve to increase or decrease the flow rate of kinetic fluid through a venturi pump to change the air pressure in the supply chamber. The controller can also selectively open and close an airlock valve. For example, the controller can open the valve when the difference between the air pressure in the supply chamber and the supply hopper is less than a threshold value. Thus, for example, before opening the airlock valve, both the supply chamber and the supply hopper can be vacuum-pressurized to substantially the same value.

[0043] The systems and processes disclosed herein offer various advantages and beneficial effects. For example, removing air from the superabsorbent material in the supply chamber before opening the airlock valve advantageously limits air entrainment from the supply hopper into the foam stream to the headbox. Furthermore, the headbox can be continuously supplied with superabsorbent material without introducing unwanted air into the foam stream to the headbox. Therefore, foam stability can be maintained while continuously supplying superabsorbent material to the foam stream to the headbox.

[0044] refer to Figure 1 and Figure 2 Example 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.

[0045] 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 1As 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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).

[0054] Other papermaking fibers that can be used include waste paper 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.

[0055] 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.

[0056] 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.

[0057] 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).

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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 2 As 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.

[0062] 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 1As 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.

[0063] 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.

[0064] 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.

[0065] 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, pressure monitoring devices 80, 82, and 84, and / or 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.

[0066] 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.

[0067] like Figure 2As 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.

[0068] like Figure 2 As 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.

[0069] 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 2As 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.

[0070] 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.

[0071] like Figure 2As 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.

[0072] 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.

[0073] like Figure 2 As 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.

[0074] 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.

[0075] 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%).

[0076] 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.

[0077] like Figure 1 As 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.

[0078] 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.

[0079] Now go to Figure 3 This illustration shows a system 200 for supplying superabsorbent material or other solid particles into 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 2The 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.

[0080] like Figure 3 As shown, system 200 includes a headbox 210 and a superabsorbent material feeder assembly 220. The headbox 210 can be configured to form a fiber web from one or more foamed fiber suspensions. For example, a foamed fiber suspension 214 can be pumped from a reservoir 212 toward the headbox 210. At the headbox 210, the foamed fiber suspension 214 can be deposited on a forming surface to form a preform fiber web, for example, as described above with respect to fiber web forming system 10. The superabsorbent material feeder assembly 220 can add superabsorbent material 202 to the foamed fiber suspension 214 upstream of the headbox 210. Thus, the foamed fiber suspension 214 flowing into the headbox 210 may include superabsorbent material 202.

[0081] Superabsorbent material feeder assembly 220 may be positioned upstream of headbox 210 along the flow of foamed fiber suspension 214 to headbox 210. Superabsorbent material feeder assembly 220 may be configured to add superabsorbent material, such as foamed fiber suspension 214, to the foam. Superabsorbent material feeder assembly 220 may include feed chamber 230, feed hopper 240, and airlock valve 250. Feed chamber 230 may be able to be filled with superabsorbent material 202. For example, superabsorbent material 202 may flow from feed reservoir 234 to feed chamber 230, and superabsorbent material 202 may be contained within interior 232 of feed chamber 230. Control valve 236 may regulate the flow of superabsorbent material 202 from feed reservoir 234 to feed chamber 230.

[0082] A pressure supply line 260 may be connected to a supply chamber 230. The pressure supply line 260 may be configured to draw air from and / or supply air to the supply chamber 230. For example, the pressure supply line 260 may be connected to a vacuum source 262, and the vacuum source 262 may generate a negative pressure to draw air out of the interior 232 of the supply chamber 230. Thus, for example, air may be removed from the supply chamber 230 via the pressure supply line 260. Furthermore, air may be removed from the supply chamber 230 while the superabsorbent material 202 remains within the interior 232 of the supply chamber 230. The vacuum source 262 may be any suitable device for generating a negative pressure relative to the ambient atmosphere. For example, the vacuum source 262 may include one or more of a venturi pump or a rotary vane pump. In other example embodiments, the pressure supply line 260 may be connected to a positive pressure source, such as a pump, compressor, etc., which generates a positive pressure to allow air to flow into the interior 232 of the supply chamber 230.

[0083] In an example implementation, the pressure level (e.g., vacuum level) in supply chamber 230 may be controlled by a back pressure regulator that receives a pressure signal from supply hopper 240 or pump 280. As another example, the pressure level in supply chamber 230 may be controlled by a control valve 264 coupled to pressure supply line 260, and control valve 264 may be configured to adjust the flow of air into and / or from supply chamber 230, for example, based on a pressure signal from supply chamber 230. As yet another example, the pressure level in supply chamber 230 may be controlled by a Venturi pump supplying compressed air, and the flow rate / pressure of compressed air may be controlled, for example, based on a pressure signal from supply chamber 230, to regulate the vacuum level.

[0084] An airlock valve 250 is disposed between the supply chamber 230 and the supply hopper 240. The airlock valve 250 is configured to regulate the flow of superabsorbent material 202 from the supply chamber 230 to the supply hopper 240. For example, when the airlock valve 250 is open, superabsorbent material 202 in the interior 232 of the supply chamber 230 can flow into the interior 242 of the supply hopper 240 through the airlock valve 250. In an example embodiment, the supply hopper 240 may be positioned below the supply chamber 230 such that when the airlock valve 250 is open, superabsorbent material 202 is gravity-fed from the interior 232 of the supply chamber 230 into the interior 242 of the supply hopper 240. Conversely, when the airlock valve 250 is closed, it prevents the flow of superabsorbent material 202 from the interior 232 of the supply chamber 230 into the interior 242 of the supply hopper 240. In an example embodiment, the airlock valve 250 may be a sliding door or other suitable valve.

[0085] The airlock valve 250 can also be configured to regulate airflow between the supply chamber 230 and the supply hopper 240. For example, when the airlock valve 250 is open, the interior 232 of the supply chamber 230 can be fluidly connected to the interior 242 of the supply hopper 240 through the airlock valve 250, allowing air to flow between the supply chamber 230 and the supply hopper 240 via the airlock valve 250. Conversely, when the airlock valve 250 is closed, it blocks airflow between the interior 232 of the supply chamber 230 and the interior 242 of the supply hopper 240.

[0086] In an example embodiment, the superabsorbent material feeder assembly 220 may include a balancing valve 252. The balancing valve 252 may be located on a balancing line between the interior 232 of the feed chamber 230 and the interior 242 of the feed hopper 240. Opening the balancing valve 252 can advantageously balance the pressure difference between the feed chamber 230 and the feed hopper 240 at a controlled rate, for example, before opening the airlock valve 250. Therefore, when the airlock valve 250 is open, rapid pressure equalization between the feed chamber 230 and the feed hopper 240 can be avoided. Furthermore, the rapid drawing of foam from the pump 280 into the superabsorbent material feeder assembly 220 or the rapid injection of air into the pump 280 due to rapid pressure equalization between the feed chamber 230 and the feed hopper 240 can be avoided or limited.

[0087] As can be seen from the above, the supply hopper 240 is configured to receive superabsorbent material 202 from the supply chamber 230. Therefore, when the airlock valve 250 is open, the interior 242 of the supply hopper 240 can be filled with superabsorbent material 202 from the interior 232 of the supply chamber 230. The supply hopper 240 can be configured to supply superabsorbent material 202 into the foamed fiber suspension 214. For example, the metering device 270 can be positioned to receive superabsorbent material 202 from the interior 242 of the supply hopper 240. In an example embodiment, the metering device 270 can be positioned at or near the bottom portion of the supply hopper 240 such that the superabsorbent material 202 is gravity-fed from the interior 242 of the supply hopper 240 into the metering device 270. The metering device 270 can be configured to supply superabsorbent material 202 into the foamed fiber suspension 214 at a selected rate. For example, metering device 270 can supply superabsorbent material 202 to pump 280 (such as an ejector), and pump 280 can draw superabsorbent material 202 into foamed fiber suspension 214 due to a pressure reduction in the motive fluid (e.g., foamed fiber suspension 214) via the Venturi effect. Metering device 270 can be any suitable device for supplying superabsorbent material 202. For example, metering device 270 may include one or more of Christy feeders, vibrating hoppers, screw feeders, etc. Figure 3In the example embodiment shown, metering device 270 includes a hopper 272 that guides superabsorbent material 202 to pump 280, and metering device 270 is disposed within vacuum chamber 274 to block or restrict ambient air from being introduced into foamed fiber suspension 214 via pump 280.

[0088] In addition to the superabsorbent material 202, the pump 280 can also draw air into the foamed fiber suspension 214. However, the superabsorbent material feeder assembly 220 may include features for limiting the volume of air entering the foamed fiber suspension 214. Thus, for example, the superabsorbent material feeder assembly 220 can advantageously add the superabsorbent material 202 to the foamed fiber suspension 214 without adversely affecting the stability of the foamed fiber suspension 214 by introducing excess air into it.

[0089] refer to Figure 3 In addition to the superabsorbent material 202, the pump 280 can also draw air from the supply hopper 240 into the foamed fiber suspension 214. When the airlock valve 250 is closed, it can also block the airflow between the supply chamber 230 and the supply hopper 240. Therefore, when the pump 280 draws the superabsorbent material 202 into the foamed fiber suspension 214, the airlock valve 250 can limit or prevent air from flowing from the supply chamber 230 into the supply hopper 240. Furthermore, the pressure supply line 260 can draw air from the supply chamber 230 when the airlock valve 250 is closed, for example, to limit the volume of air transferred from the supply chamber 230 into the supply hopper 240 when the airlock valve 250 is open. As can be seen from the above, various components of the superabsorbent material supply assembly 220 can be coordinated to limit, for example, the volume of air entering the foamed fiber suspension 214 via the pump 280, while the superabsorbent material supply assembly 220 supplies superabsorbent material 202 into the foamed fiber suspension 214.

[0090] In an example embodiment, the metering device 270, supply hopper 240, supply chamber 230, and other components of the superabsorbent material supply assembly 220 may be sealed relative to ambient air to limit or prevent the introduction of ambient air into the foamed fiber suspension 214 via pump 280. However, it should be understood that the superabsorbent material supply assembly 220 may be configured to allow limited release of air or other gases into the superabsorbent material supply assembly 220 to facilitate the supply of superabsorbent material 202 into the foamed fiber suspension 214. However, limiting the release of air or other gases is to avoid negatively impacting the stability of the foamed fiber suspension 214.

[0091] like Figure 3As shown, system 200 may also include a processing device or controller 290, or be operatively communicable to such processing device or controller, which may typically be configured to facilitate the operation of at least a portion of system 200. In this regard, control valve 236, airlock valve 250, control valve 264, metering device 270, various sensors, and other components of system 200 may communicate with controller 290. Thus, for example, controller 290 may receive input from sensors and may regulate the operation of components of system 200 (such as airlock valve 250) at least in part based on the input from the sensors. Control valve 236, airlock valve 250, control valve 264, metering device 270, various sensors, and other components of system 200 may communicate with controller 290 via, for example, one or more signal lines or a shared communication bus. In this way, input / output (“I / O”) signals may be routed between controller 290 and various operating components of system 200.

[0092] 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 (CPUs), graphics processing units (GPUs), processing units performing other special-purpose calculations, 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 290 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.

[0093] The controller 290 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.

[0094] For example, controller 290 may be operable to execute programming instructions or microcontroller code associated with the operating cycle 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, adjusting the operating parameters of the airlock valve 250, etc. Furthermore, it should be noted that controller 290, 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 290.

[0095] The memory device may also store data that can be retrieved, manipulated, created, or stored by one or more processors or portions of controller 290. 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 controller 290) 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 controller 290 via any suitable network, such as a high-bandwidth local area network (LAN) or wide area network (WAN). In this regard, for example, controller 290 may also include a communication module or interface that can be used, for example, to communicate with one or more other components of system 200, controller 290, 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.

[0096] As noted above, controller 290 can be configured to control the operation of control valve 236, airlock valve 250, control valve 264, metering device 270, and other components of system 200 based at least in part on inputs from various sensors, such as supply chamber pressure sensor 292, supply hopper pressure sensor 294, and level sensors 296, 298. Supply chamber pressure sensor 292 can be configured to measure the air pressure within supply chamber 230. Therefore, for example, supply chamber pressure sensor 292 can be any suitable pressure sensor for measuring the pressure within the interior 232 of supply chamber 230. Supply hopper pressure sensor 294 can be configured to measure the air pressure within supply hopper 240. Therefore, for example, supply hopper pressure sensor 294 can be any suitable pressure sensor for measuring the pressure within the interior 242 of supply hopper 240. Level sensors 296, 298 can be configured to measure the level of superabsorbent material 202 within supply hopper 240. As an example, level sensors 296 and 298 may include one or more of optical level sensors, ultrasonic level sensors, capacitive level sensors, vibration point level sensors, rotary propeller level sensors, etc.

[0097] In an example implementation, controller 290 can control components of system 200 to supply superabsorbent material 202 to the foamed fiber suspension 214. For example, controller 290 can activate metering device 270 to supply superabsorbent material 202 from supply hopper 240 to pump 280, which draws superabsorbent material 202 into the foamed fiber suspension 214. Controller 290 can also detect the level of superabsorbent material 202 in supply hopper 240 via level sensors 296, 298. When supply hopper 240 requires more superabsorbent material 202, controller 290 can operate various components of superabsorbent material feeder assembly 220 to add superabsorbent material 202 to supply hopper 240 without adversely affecting the stability of foamed fiber suspension 214 by introducing excess air into it. For example, controller 290 may open control valve 234 to allow superabsorbent material 202 from supply reservoir 234 to flow into supply chamber 230. When the interior 232 of supply chamber 230 is filled with superabsorbent material 202, controller 290 may close control valve 234 to stop the flow of superabsorbent material 202 into supply chamber 230. Controller 290 may also open control valve 264 to remove air from supply chamber 230 via pressure supply line 260. When superabsorbent material 202 is added to supply chamber 230 and air is removed from supply chamber 230, controller 290 may keep airlock valve 250 closed. Conversely, when supply chamber 230 is filled with superabsorbent material 202 and air has been removed from supply chamber 230 by pressure supply line 260, controller 290 may open airlock valve 250 to allow superabsorbent material 202 in supply chamber 230 to flow through airlock valve 250 into supply hopper 240. Specifically, when the pressure measurements from the supply chamber pressure sensor 292 and the supply hopper pressure sensor 294 are (e.g., approximately) equal, the controller 290 may open the airlock valve 250. By removing air from the supply chamber 230 before opening the airlock valve 250, the volume of air entering the supply hopper 240 from the supply chamber 230 can be reduced or limited to a degree that does not affect the stability of the foamed fiber suspension 214.

[0098] As can be seen from the above, superabsorbent material 202 can be added to supply hopper 240 via an airlock method, wherein discrete volumes of superabsorbent material 202 and air are added to a separate supply chamber 230. When full, the air in supply chamber 230 is evacuated by a pressure supply line 260 independent of pump 280, for example, until the pressure in supply chamber 230 is approximately equal to the pressure in supply hopper 240. Then, pressure supply line 260 can be closed, and airlock valve 250 can be opened to transfer superabsorbent material 202 from supply chamber 230 to supply hopper 240. Once superabsorbent material 202 has been added to supply hopper 240, airlock valve 250 can be closed and the process repeated to allow continuous feeding of superabsorbent material 202 into the foamed fiber suspension 214 flowing into headbox 210.

[0099] Figure 4 A method 400 for foam forming according to an example implementation of this subject is illustrated. As an example, method 400 can be implemented in system 200 (… Figure 3 This system can be used or employed in conjunction with the system to help supply superabsorbent material to a foam stream in a headbox. The controller 290 of system 200 can be programmed or configured to implement method 400. Although method 400 is described in more detail below in the context of system 200, it should be understood that method 400 can be used or employed within any suitable system or process in alternative example embodiments.

[0100] At 410, the superabsorbent material flows into the supply chamber. For example, at 410, superabsorbent material 202 may flow from supply reservoir 234 into supply chamber 230. Furthermore, controller 290 may open control valve 236 to allow superabsorbent material 202 to flow from supply reservoir 234 into supply chamber 230. As another example, superabsorbent material 202 may be manually added to supply chamber 230.

[0101] At 420, air is removed from the supply chamber. For example, at 420, pressure supply line 260 may remove air from supply chamber 230. Additionally, controller 290 may open control valve 264 to evacuate air from supply chamber 230 through pressure supply line 260. In some example embodiments, method 400 may include: at 420, measuring the air pressure within the supply stream. For example, supply chamber pressure sensor 292 may measure the air pressure within supply chamber 230. Furthermore, method 400 may also include adjusting the vacuum pressure for removing air from the supply chamber based on the measured air pressure in the supply hopper. For example, controller 290 may adjust a back pressure regulator on pressure supply line 260 based at least in part on the air pressure within supply chamber 230 measured by supply chamber pressure sensor 292. As another example, controller 290 may adjust the flow of kinetic fluid via a Venturi pump configured as a vacuum source 262 based at least in part on the air pressure within supply chamber 230 measured by supply chamber pressure sensor 292. Therefore, for example, the vacuum applied to supply chamber 230 at 420 can be controlled to, for example, approximately match the pressure within supply hopper 240. In other example embodiments, air can be added to the supply chamber. For example, at 420, pressure supply line 260 can supply air to supply chamber 230.

[0102] At 430, the airlock valve between the supply chamber and the supply hopper can be opened, allowing superabsorbent material to transfer from the supply chamber to the supply hopper. For example, at 430, airlock valve 250 can be opened, allowing superabsorbent material 202 in the interior 232 of the supply chamber 230 to flow into the interior 242 of the supply hopper 240 through airlock valve 250. Furthermore, at 430, controller 290 can open airlock valve 250. In some example embodiments, the airlock valve can be opened when the difference between the air pressure in the supply chamber and the air pressure in the supply hopper is less than a threshold. For example, controller 290 can open airlock valve 250 when the difference between the measurements from supply chamber pressure sensor 292 and supply hopper pressure sensor 294 is less than a threshold. The threshold can be selected such that the air pressure in the supply chamber 230 and the supply hopper 240 is approximately equal before opening airlock valve 250. For example, the threshold may not be greater than half a bar (0.5 bar). At 430, controller 290 can open balancing valve 252 to balance the pressure difference between supply chamber 230 and supply hopper 240 at a controlled rate, for example, before opening airlock valve 250. Therefore, the rapid pumping of foam from pump 280 into superabsorbent material feeder assembly 220 or the rapid injection of air into pump 280 due to rapid pressure equalization of supply chamber 230 and supply hopper 240 can be avoided or limited.

[0103] At 440, superabsorbent material is metered into the foam stream leading to the headbox. For example, at 440, metering device 270 supplies superabsorbent material 202 from supply hopper 240 into the foamed fiber suspension 214 at a selected rate. Controller 290 can activate metering device 270. Method 400 may further include drawing superabsorbent material into the foam stream leading to the headbox via a pump (such as an ejector). For example, metering device 270 may supply superabsorbent material 202 to pump 280, and pump 280 may draw superabsorbent material 202 into the foamed fiber suspension 214. Pump 280 may also draw air from the supply hopper into the foam. For example, in addition to superabsorbent material 202, pump 280 may also draw air from supply hopper 240 into the foamed fiber suspension 214. When the airlock valve 250 is closed, it can also block the airflow between the supply chamber 230 and the supply hopper 240. Therefore, when the pump 280 draws the superabsorbent material 202 into the foamed fiber suspension 214, the airlock valve 250 can restrict or prevent air from the supply chamber 230 from flowing into the supply hopper 240.

[0104] Figure 4 For illustrative and discussion purposes, the steps performed in a specific order are described. Those skilled in the art will understand, using the disclosure provided herein, that the steps of any method discussed herein may be adapted, rearranged, expanded, omitted, or modified in various ways without departing from the scope of this disclosure.

[0105] 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.

[0106] Example Implementation Plan

[0107] First example embodiment: A foam forming system comprising: a headbox; a superabsorbent material feeder assembly positioned upstream of the headbox in a flow path for foam to the headbox, the superabsorbent material feeder assembly being configured to add superabsorbent material to the foam, the superabsorbent material feeder assembly comprising: a supply chamber capable of being filled with the superabsorbent material; a supply hopper; an airlock valve disposed between the supply chamber and the supply hopper, the airlock valve being configured to open and close to selectively connect the supply chamber and the supply hopper, wherein when the airlock valve is open, the superabsorbent material in the supply chamber can flow into the supply hopper; and a pressure supply line coupled to the supply chamber and configured to allow air to flow into and / or out of the supply chamber.

[0108] Second example implementation: According to the foam forming system of the first example implementation, the superabsorbent material feeder assembly further includes a pump positioned on the flow path for the foam to the headbox, and the pump is configured to draw the superabsorbent material into the foam.

[0109] Third example implementation: The foam forming system according to the second example implementation, wherein the pump is configured to draw air from the supply hopper into the foam, and the airlock valve blocks the airflow between the supply chamber and the supply hopper when the airlock valve is closed.

[0110] Fourth example implementation: A foam forming system according to any one of the first to third example implementations, wherein the superabsorbent material feeder assembly further includes an isolation valve connected to the pressure supply line.

[0111] Fifth Example Implementation: A foam forming system according to any one of the first to fourth example implementations, wherein: the superabsorbent material feeder assembly further includes a controller, a supply chamber pressure sensor, and a supply hopper pressure sensor; the supply chamber pressure sensor is configured to measure the air pressure inside the supply chamber; the supply hopper pressure sensor is configured to measure the air pressure inside the supply hopper; and the controller communicates with the airlock valve, the supply chamber pressure sensor, and the supply hopper pressure sensor; and the controller is configured to open the valve at least in part based on an air pressure difference between the supply chamber and the supply hopper being less than a threshold value.

[0112] Sixth Example Implementation: A foam forming system according to any one of the first to fifth example implementations, wherein: the superabsorbent material feeder assembly further includes a back pressure regulator, a feed hopper pressure sensor, and a controller; the back pressure regulator is configured to regulate the pressure in the pressure supply line; the feed hopper pressure sensor is configured to measure the air pressure within the feed hopper; and the controller communicates with the feed hopper pressure sensor and the back pressure regulator; and the controller is configured to regulate the back pressure regulator based at least in part on the air pressure within the feed hopper.

[0113] Seventh Example Implementation: A foam forming system according to any one of the first to sixth example implementations, wherein: the superabsorbent material feeder assembly further includes a Venturi pump, a feed hopper pressure sensor, and a controller; the Venturi pump is connected to the pressure supply line; the feed hopper pressure sensor is configured to measure the air pressure within the feed hopper; and the controller communicates with the feed hopper pressure sensor; and the controller is configured to regulate the flow of kinetic fluid through the Venturi pump based at least in part on the air pressure within the feed hopper.

[0114] Eighth Example Implementation: A foam forming system according to any one of the first to seventh example implementations, wherein the supply chamber is disposed above the airlock valve and the supply hopper is disposed below the airlock valve.

[0115] Ninth Example Implementation: A foam forming system according to any one of the first to eighth example implementations, the foam forming system further comprising a metering device configured to adjust the flow of the superabsorbent material from the supply hopper to the flow path for foam to the headbox.

[0116] Tenth Example Implementation: A particulate material feeder for a foam forming system, the particulate material feeder comprising: a feed chamber capable of being filled with particulate material; a feed hopper positioned below the feed chamber; an airlock valve disposed between the feed chamber and the feed hopper, the airlock valve being configured to open and close to selectively connect the feed chamber and the feed hopper, wherein when the airlock valve is open, the particulate material in the feed chamber can flow into the feed hopper; and a pressure supply line connected to the feed chamber and configured to allow air to flow into and / or out of the feed chamber.

[0117] Eleventh Example Implementation: A method for supplying particulate material within a foam forming process, the method comprising: causing the particulate material to flow into a supply chamber;

[0118] Remove air from the supply chamber; open the airlock valve between the supply chamber and the supply hopper to transfer the particulate material from the supply chamber to the supply hopper; and meter the particulate material into the foam stream to the headbox.

[0119] Twelfth Example Implementation: According to the method described in the eleventh example implementation, opening the airlock valve includes opening the airlock valve when the difference between the air pressure in the supply chamber and the air pressure in the supply hopper is less than a threshold.

[0120] Thirteenth Example Implementation: The method according to the eleventh or twelfth example implementation further includes pumping the particulate material into the foam stream to the headbox via a pump.

[0121] Fourteenth Example Implementation: The method according to any one of the eleventh to thirteenth example implementations, wherein the pump also draws air from the supply hopper into the foam, and when the airlock valve is closed, the airlock valve blocks the airflow between the supply chamber and the supply hopper.

[0122] Fifteenth Example Implementation: The method according to any one of the eleventh to fourteenth example implementations, the method further comprising: measuring the air pressure in the supply chamber; and measuring the air pressure in the supply hopper, wherein opening the airlock valve comprises opening the airlock valve based at least in part on the air pressure difference between the supply chamber and the supply hopper being less than a threshold.

[0123] Sixteenth Example Implementation: The method according to any one of the eleventh to fifteenth example implementations, the method further comprising: measuring the air pressure in the supply hopper; and adjusting the pressure in a pressure supply line via a back pressure regulator based at least in part on the air pressure in the supply hopper, the pressure supply line causing the air to flow into and / or out of the supply chamber.

[0124] Seventeenth Example Implementation: The method according to any one of the eleventh to sixteenth example implementations, the method further comprising: measuring the air pressure within the supply hopper; and regulating the flow of kinetic fluid via a Venturi pump connected to a pressure supply line, at least in part, based on the air pressure within the supply hopper, the pressure supply line allowing the air to flow into and / or out of the supply chamber.

[0125] Eighteenth Example Implementation: A system for supplying particulate material within a foam forming process, substantially as described herein.

[0126] Nineteenth Example Implementation: A method for supplying particulate material within a foam forming process, substantially as described herein.

Claims

1. A foam forming system, the foam forming system comprising: headbox; and A superabsorbent material feeder assembly, positioned upstream of the headbox in a flow path for foam to the headbox, the superabsorbent material feeder assembly being configured to add superabsorbent material to the foam, the superabsorbent material feeder assembly comprising: A supply chamber capable of being filled with the superabsorbent material; Supply hopper; An airlock valve is disposed between the supply chamber and the supply hopper, the airlock valve being configured to open and close selectively connect the supply chamber and the supply hopper, wherein when the airlock valve is open, the superabsorbent material in the supply chamber can flow into the supply hopper; and A pressure supply line is connected to the supply chamber and is configured to allow air to flow into and / or out of the supply chamber.

2. The foam forming system of claim 1, wherein the superabsorbent material feeder assembly further comprises a pump positioned on the flow path for the foam to the headbox, and the pump is configured to draw the superabsorbent material into the foam.

3. The foam forming system of claim 2, wherein the pump is configured to draw air from the supply hopper into the foam, and the airlock valve blocks airflow between the supply chamber and the supply hopper when the airlock valve is closed.

4. The foam forming system of claim 1, wherein the superabsorbent material feeder assembly further includes an isolation valve connected to the pressure supply line.

5. The foam forming system according to claim 1, wherein: The superabsorbent material feeder assembly also includes a controller, a supply chamber pressure sensor, and a supply hopper pressure sensor; The supply chamber pressure sensor is configured to measure the air pressure inside the supply chamber; The supply hopper pressure sensor is configured to measure the air pressure inside the supply hopper; and The controller communicates with the airlock valve, the supply chamber pressure sensor, and the supply hopper pressure sensor. and The controller is configured to open the airlock valve based at least in part on an air pressure difference between the supply chamber and the supply hopper that is less than a threshold.

6. The foam forming system according to claim 1, wherein: The superabsorbent material feeder assembly also includes a back pressure regulator, a feed hopper pressure sensor, and a controller; The back pressure regulator is configured to regulate the pressure in the pressure supply line; The supply hopper pressure sensor is configured to measure the air pressure inside the supply hopper; and The controller communicates with the supply hopper pressure sensor and the back pressure regulator; and The controller is configured to adjust the back pressure regulator based at least in part on the air pressure within the supply hopper.

7. The foam forming system according to claim 1, wherein: The superabsorbent material feeder assembly also includes a Venturi pump, a feed hopper pressure sensor, and a controller; The Venturi pump is connected to the pressure supply line; The supply hopper pressure sensor is configured to measure the air pressure inside the supply hopper; and The controller communicates with the pressure sensor of the supply hopper; and The controller is configured to regulate the flow of kinetic fluid through the venturi pump based at least in part on the air pressure within the supply hopper.

8. The foam forming system according to claim 1, wherein the supply chamber is disposed above the airlock valve and the supply hopper is disposed below the airlock valve.

9. The foam forming system of claim 1, further comprising a metering device configured to regulate the flow of the superabsorbent material from the supply hopper to the flow path for foam to the headbox.

10. A particulate material feeder for a foam forming system, the particulate material feeder comprising: Supply chamber, the supply chamber being capable of being filled with particulate material; A supply hopper, which is positioned below the supply chamber; An airlock valve is disposed between the supply chamber and the supply hopper. The airlock valve is configured to open and close to selectively connect the supply chamber and the supply hopper. When the airlock valve is open, the particulate material in the supply chamber can flow into the supply hopper. and A pressure supply line is connected to the supply chamber and is configured to allow air to flow into and / or out of the supply chamber.

11. A method for supplying particulate material in a foam forming process, the method comprising: This allows the granular material to flow into the supply chamber; Air is removed from the supply chamber; Open the airlock valve between the supply chamber and the supply hopper to transfer the particulate material from the supply chamber to the supply hopper; as well as The particulate material is metered into the foam stream in the headbox.

12. The method of claim 11, wherein opening the airlock valve comprises opening the airlock valve when the difference between the air pressure in the supply chamber and the air pressure in the supply hopper is less than a threshold value.

13. The method of claim 11, further comprising pumping the particulate material into the foam stream in the headbox via a pump.

14. The method of claim 13, wherein the pump also draws air from the supply hopper into the foam, and when the airlock valve is closed, the airlock valve blocks the airflow between the supply chamber and the supply hopper.

15. The method according to claim 11, further comprising: Measure the air pressure in the supply chamber; as well as Measure the air pressure inside the supply hopper. Opening the airlock valve includes at least in part based on the air pressure difference between the supply chamber and the supply hopper being less than a threshold.

16. The method according to claim 11, further comprising: Measure the air pressure inside the supply hopper; as well as The pressure in the pressure supply line is regulated via a back pressure regulator based at least in part on the air pressure within the supply hopper, the pressure supply line allowing the air to flow into and / or out of the supply chamber.

17. The method according to claim 11, further comprising: Measure the air pressure inside the supply hopper; as well as The flow of kinetic fluid via a Venturi pump, connected to a pressure supply line, is regulated at least in part based on the air pressure within the supply hopper, which allows the air to flow into and / or out of the supply chamber.

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