Patent Description:
As known, disposable absorbent articles such as diapers or training pants for babies, sanitary napkins or towels or products for adult incontinence, comprises an absorbent core arranged in between a liquid permeable topsheet and a liquid impermeable backsheet with eventually an acquisition distribution layer (ADL) in between the topsheet and the absorbent core. The general purpose of such absorbent articles is to absorb, distribute and store various types of body exudates, while providing a high level of comfort and sense of dryness to the wearer during use of the absorbent article. In order to do so, the disposables typically comprise an absorbent core, or absorbent body, which is capable of quickly absorbing and retaining the exudates. The absorbent core comprises absorbent material such as cellulosic fibres or fluff or fluff pulp and/or of particles of superabsorbent material (SAP). The absorbent material is usually contained, encapsulated or enclosed in a core wrap. The core wrap can comprise one core wrap sheet extending above and under and on the side of the absorbent material thereby fully or at least partially covering the absorbent material. Alternatively, the core wrap can comprise two core wrap sheet, an upper core wrap and a lower absorbent core wrap, the absorbent material between arranged in between. In recent years, more and more absorbent cores comprise at least one channel substantially free of absorbent material. The at least one channel is formed by adhering the lower core wrap sheet to the upper core wrap sheet, or the portion of the sheet above to the portion of the sheet under when the core wrap comprises one single sheet.

The process and apparatus commonly used for the formation of absorbent bodies is generally described below.

The absorbent cores are manufactured using an apparatus comprising a defibrating device, such as a mill or more specifically a hammermill, which defibers, or pulverizes, a sheet of pulp material, resulting in pulp fibers. Additionally, the apparatus comprises a tube feeding superabsorbent particles within said duct and superabsorbent particles are discharged into said duct. In this way, the superabsorbent particles and the pulp fibers flow together within the duct. An airflow conveys the pulp fibers and superabsorbent particles to a forming pocket where the absorbent fibers and superabsorbent particles are deposited thereby forming a moulded absorbent material deposit structure.

It is required that the absorbent material, in particular the superabsorbent particles, have an adequate and uniform distribution, since the functionality of the absorbent core in the disposable article will depend on that.

Documents <CIT>, <CIT> and <CIT> all disclose devices for distributing superabsorbent polymer where a valve, nozzle or barrier is arranged at the end of a tube, said nozzle or valve deflecting all the superabsorbent polymer to have an allegedly homogenous distribution.

The above publications have made attempts in providing substantially uniform distribution of the particulate super absorbent material. However, none of the foregoing appears to have adequately addressed the problem and there remains a need to have a more uniform distribution of superabsorbent particles. It is thus an object of the present invention to provide a method and apparatus that solves these problems by making the distribution of the super absorbent material within the forming pockets more uniform. An apparatus for distributing superabsorbent particles is also known from <CIT>.

The present invention pertains to an apparatus for distributing superabsorbent particles onto a substrate, the apparatus comprising a discharge pipe for conveying a stream comprising superabsorbent particles and a first airflow, said discharge pipe comprising a conveying section and an outlet nozzle, said outlet nozzle comprising a straight portion preferably arranged in the continuity of the conveying section and a deflecting portion characterized in that the deflecting portion comprises deflecting means arranged in a way that only a portion of the stream of superabsorbent particle and first airflow is deflected and the other portion of said stream is not deflected ,creating a crossflow between the portion of the said stream that is deflected and the portion of said stream that is not deflected, preferably at the outlet of the discharging pipe.

According to an embodiment, the deflecting means define a first angle between the conveying section and the deflection portion, said first angle being comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°, more preferably between <NUM>° and <NUM>°.

According to an embodiment, the discharge pipe extends longitudinally, transversally and vertically, said outlet nozzle comprises a top wall, a bottom wall, a first and second side wall, each wall comprising a proximal end connected to the conveying section and a distal end arranged at the outlet of the discharging pipe, the distal end of the top wall extending longitudinally beyond the distal end of the bottom wall and/or the distal end of the first side wall extending longitudinally beyond the distal end of the second side wall.

According to an embodiment, the discharge pipe further comprises a first feeding tube conveying a first airflow, a second feeding tube conveying superabsorbent particles and a venturi section arranged at the junction between the first and second feeding tubes and the conveying section, the first and second feeding tubes and the conveying section all being fluidically connected, first and second feeding tubes being arranged upstream of the conveying section with respect to the direction of flow.

According to an embodiment, the venturi section is formed by the second feeding tube partially extending within first feeding tube and reducing the cross-sectional area of the discharge pipe for the first airflow, meaning for the passage of the first airflow.

According to an embodiment, the first feeding tube and the second feeding tube define a third angle, said third angle being comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°.

According to an embodiment, the outlet nozzle comprises a rectangular transversal cross section and the cross-sectional area of outlet nozzle is lesser than the cross-sectional area of the conveying section.

The present disclosure also relates to an apparatus suitable for forming moulded absorbent material deposit structures to be used as absorbent cores for absorbent articles, the apparatus comprising:.

According to the present disclosure, the discharge pipe extends partially within the discharging conduit, the outlet nozzle being arranged within the discharging conduit in a way that the discharge pipe sprays superabsorbent particles into the discharging conduit and into the mould cavity of the forming pockets.

According to an embodiment, the feeding unit comprises two discharging conduits, each conduit being fluidically connected to the defibrating station and each conduit comprising a discharge pipe extending partially within its respective discharging conduit, the outlet nozzle of each pipe being arranged within its respective discharging conduit.

According to an embodiment, the apparatus extends longitudinally, transversally and vertically, the deflecting portion and the upper wall of the housing defining the discharging conduit extend in the parallel planes, said planes being defined by the longitudinal and transversal directions.

According to an embodiment, the discharge pipe and the upper wall of the housing defining the discharging conduit define a second angle, said second angle being comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°.

According to an embodiment, the discharge pipe is arranged within the discharging conduit in a way that the distance between the distal end of the deflecting portion and the upper wall of the housing with respect to the vertical direction is comprised between <NUM> and <NUM> and/or the shortest distance between the distal end of the deflecting portion and the outer surface of the forming drum, preferably the outer surface of the forming pockets with respect to the longitudinal direction is comprised between <NUM> and <NUM>.

According to an embodiment, the apparatus comprises a discharge pipe orientation device enabling to change the inclination of the discharge pipe.

The present disclosure also relates to a method for forming moulded absorbent material deposit structures to be used as absorbent cores for absorbent articles using an apparatus as described hereabove, the method comprising:.

The drawings and figures are illustrative in nature and not intended to limit the subject matter defined by the claims. The following detailed description can be understood when read in conjunction with the following drawings, where similar or identical structures are indicated with the same reference numerals in which:.

As discussed hereabove, there remains a need for a more efficient way of producing absorbent cores comprising a homogeneous, or uniform, distribution of superabsorbent particles. The present disclosure relates to an apparatus suitable for distributing superabsorbent particles uniformly onto a substrate and as well as an apparatus suitable for forming moulded absorbent material deposit structures to be used as absorbent cores for absorbent articles comprising said apparatus suitable for distributing superabsorbent particles homogeneously onto a substrate. The present disclosure also relates to a method for forming moulded absorbent material deposit structures to be used as absorbent cores using said apparatus. However, other mixtures of materials may be produced employing the present invention, depending on the particular parameters desired in the absorbent body. Such alternative configurations and uses are contemplated as being within the scope of the present invention.

As used herein, the following terms have the following meanings:
"A", "an", and "the" as used herein refers to both singular and plural unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more compartments.

"About" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, encompass variations of +/-<NUM>% or less, even more preferably +/-<NUM> % or less, and still more preferably +/-<NUM>% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention.

The term "channel(s)" as used herein means fluid distribution means within the absorbent core adapted to favor exudate flow there along and are typically intended to exclude embossing patterns or ducts formed by compression from the meaning thereof and rather include structures that are substantially free of absorbent material instead of comprising compacted absorbent material. Channels are commonly known in the art. Channels herein are formed by joining upper and lower layers of a core wrap as will be described in more detail hereinbelow. Channels preferably comprise recessed regions forming visible conduits or passages typically extending along the longitudinal axis of the core and having a depth in a direction perpendicular to said longitudinal axis. By "visible" it is herein intended clearly visible by naked eye. Typically the channels have a width generally greater than <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, even more preferably from greater than <NUM> to less than <NUM>. The one or more channels are arranged within the inner periphery of the absorbent core, i.e. the inner, or interior, space defined by the periphery of the absorbent core, such that each of the channel(s) is bounded, or surrounded, by absorbent material. Additionally, the length of the channels may be from <NUM> % to <NUM> % of the length of the absorbent core so that again the one or more channels are bounded by absorbent material.

"Comprise", "comprising", "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

"Absorbent article" refers to devices that absorb and contain liquid, and more specifically, refers to devices that are placed against or in proximity to the body of the wearer to absorb and contain the various exudates discharged from the body. Absorbent articles include but are not limited to diapers, adult incontinence briefs, training pants and diaper holders and liners, Absorbent articles preferably comprise a longitudinal axis and a transversal axis perpendicular to said longitudinal axis. The longitudinal axis is hereby conventionally chosen in the front-to-back direction of the article when referring to the article being worn, and the transversal axis is conventionally chosen in the left-to-right direction of the article when referring to the article being worn. The absorbent article includes a chassis and may also include other components, such as liquid wicking layers, liquid intake layers, liquid distribution layers, transfer layers, barrier layers, wrapping layers and the like, as well as combinations thereof. Disposable absorbent articles and the components thereof can operate to provide a skin-facing surface and a garment-facing surface.

A "chassis" of a disposable absorbent article can include a liquid pervious topsheet, a backsheet joined to the top sheet, and an absorbent body positioned and held between the top sheet and the back sheet. The top sheet is operatively permeable to the liquids that are intended to be held or stored by the absorbent article, and the back sheet may or may not be substantially impervious or otherwise operatively impermeable to the intended liquids. The chassis comprises a front waist portion, a back waist portion, and an intermediate crotch portion which interconnects the front and back waist portions. When used herein, reference to a "front" portion refers to that part of the chassis which is generally located on the front of a wearer when in use. Reference to the "back" portion refers to the portion of the chassis generally located at the back of the wearer when in use, and reference to the "crotch" portion refers to that portion which is generally located between the legs of a wearer when in use. The crotch portion is an area where repeated fluid surge typically occurs.

The "absorbent core" or "absorbent body" as used herein are synonymous and correspond to the absorbent structure disposed between the topsheet and the backsheet of the chassis and is capable of absorbing and retaining liquid body exudates. The size and the absorbent capacity of the absorbent body should be compatible with the size of the intended wearer and the liquid loading imparted by the intended use of the chassis. Further, the size and the absorbent capacity of the absorbent body can be varied to accommodate wearers ranging from infants through adults. It may be manufactured in a wide variety of shapes (for example, rectangular, trapezoidal, T-shape, I-shape, hourglass shape, etc.) and from a wide variety of materials. Examples of commonly occurring absorbent materials are cellulosic fluff pulp, tissue layers, highly absorbent polymers (so called superabsorbent polymer particles (SAP)), absorbent foam materials, absorbent nonwoven materials or the like. It is common to combine cellulosic fluff pulp with superabsorbent polymers in an absorbent body. It can contain embossed channels, channels substantially free of material, channels with lower basis weight than the rest of the body, etc..

"Acquisition and distribution layer", "ADL" or "surge management portion" refers to a sublayer which preferably is a nonwoven wicking layer under the top sheet of an absorbent product, which speeds up the transport and improves distribution of fluids throughout the absorbent body.

The term "adhesive" as used herein is intended to refer to any suitable hot melt, water or solvent borne adhesive that can be applied to a surface in the required pattern or network of adhesive areas. Accordingly, suitable adhesives include conventional hot melt adhesives, pressure-sensitive adhesives and reactive adhesives (i.e., polyurethane).

"Bonded" refers to the joining, adhering, connecting, attaching, or the like, of at least two elements. Two elements will be considered to be bonded together when they are bonded directly to one another or indirectly to one another, such as when each is directly bonded to intermediate elements.

The term "backsheet" refers to a material forming a liquid impervious cover of the chassis of the absorbent article. The back sheet prevents the exudates contained in the absorbent body from wetting articles such as bedsheets and overgarments which contact the disposable absorbent article. The back sheet may be a composite layer composed of multiple components assembled side-by-side or laminated.

The term "channel", "conduit", "duct", "pipe" as used herein are synonyms and mean a tube or a passageway for conveying a fluid e.g. air, said channel, conduit, duct or pipe being defined by a housing or wall(s) defining an internal volume in which said fluid flows through. Similarly, "convey", "transport", "guide" are synonymous verbs and are interchangeable and mean that are moved, directed or conducted from one point to another.

The term "deflected" as used herein means deviated, ricocheted, rebounded off a surface, that has changed direction after hitting something, that has an obstacle in its course and is forced to change trajectory, that is caused to change direction or that is turn aside from a straight course. Preferably, this term is used herein as a significant change of direction or trajectory. In opposition the term "undeflected" means that does not significantly change direction, that is not or slightly deviated.

The term "disposable" is used herein to describe absorbent articles that generally are not intended to be laundered or otherwise restored or reused as an absorbent article (i.e., they are intended to be discarded after a single use and, preferably, to be recycled, composted or otherwise disposed of in an environmentally compatible manner).

By "fluidically connected" as used herein in reference to two elements is meant that a fluid, e.g. air, can circulate between these two elements. For example, two fluidically connected ducts means that a fluid can flow from one duct to the other.

The terms "fluff pulp", "pulp fibers", "fluff", "pulp" and "absorbent fibers" as used herein are all synonymous and interchangeable and generally reference to an absorbent material, preferably made out of fibers such as cellulosic fibers or any hydrophilic and absorbing fibers.

As used herein, the term "impermeable" or "impervious" generally refers to articles, chassis and/or elements that are substantially not penetrated by aqueous fluid through the entire thickness thereof under a pressure of <NUM> kPa or less. Preferably, the impermeable article or element is not penetrated by aqueous fluid under pressures of <NUM> kPa or less. More preferably, the impermeable article or element is not penetrated by fluid under pressures of <NUM> kPa or less. An article or element that is not impermeable is permeable.

The terms "inlet", "outlet", "upstream" and "downstream" are with respect to the flow direction of a fluid, e.g. an airflow.

"Join", "joining", "joined", or variations thereof, when used in describing the relationship between two or more elements, means that the elements can be connected together in any suitable manner, such as by heat sealing, ultrasonic bonding, thermal bonding, by adhesives, stitching, or the like. Further, the elements can be joined directly together, or may have one or more elements interposed between them, all of which are connected together.

The use of the term "layer" can refer, but is not limited, to any type of substrate, such as a woven web, nonwoven web, films, laminates, composites, elastomeric materials, or the like, or even formulations, such as adhesives, that form a substrate upon a change in conditions (e.g. solidification of a hotmelt adhesive when the temperature drops below a predetermined amount). A layer can be liquid and air permeable, permeable to air but impermeable to liquids, impermeable both to air and liquid, or the like. When used in the singular, it can have the dual meaning of a single element or a plurality of elements.

As used herein, the terms "longitudinal", "transversal" and "vertical" are with respect to the apparatus suitable for forming moulded absorbent material deposit structures to be used as absorbent cores for absorbent articles in an assembled state or installed state, said apparatus comprising the apparatus suitable for distributing superabsorbent particles homogeneously onto a substrate. The term "in the direction" as used herein means along that direction, e.g. in the longitudinal direction means along the longitudinal direction.

The terms "mesh", "foraminous forming screen" or "mesh substrate" as used herein are synonymous and mean a screen, a net, a material made of a network of wire(s) or thread(s), an interlaced structure or a weblike pattern or construction, all that have small openings to let air pass through while retaining, or blocking other material such as absorbent material, nonwoven material, or in other words that is air permeable.

The term "nonwoven substrate/material/web" means a sheet material having a structure of individual fibers or threads which are interlaid, but not in a regular manner such as occurs with knitting or weaving processes. Nonwoven fabrics or webs have been formed from many processes such as for example, meltblowing processes, spunbonding processes, and bonded carded web processes.

The terms "outlet nozzle" and "outlet section" as used herein are synonymous and interchangeable and refer to the same element, i.e. the extremity of the discharge pipe, namely the extremity of the discharging pipe arranged within the discharging conduit and enabling a crossflow of sub-streams.

By the terms "particle", "particles", "particulate", "particulates" and the like, it is meant that the material is generally in the form of discrete units. The units can comprise granules, powders, spheres, pulverized materials or the like, as well as combinations thereof. The particles can have any desired shape such as, for example, cubic, rod-like, polyhedral, spherical or semi-spherical, rounded or semi-rounded, angular, irregular, etc. Shapes having a large greatest dimension/smallest dimension ratio, like needles, flakes and fibers, are also contemplated for inclusion herein. The terms "particle" or "particulate" may also include an agglomeration comprising more than one individual particle, particulate or the like. Additionally, a particle, particulate or any desired agglomeration thereof may be composed of more than one type of material.

The term "section" as used herein means a segment, a part, a portion of, a division or a component of an element. For example a section of a pipe means a portion of that pipe.

Use of the term "substrate" includes, but is not limited to, woven or nonwoven webs, porous films, ink permeable films, paper, composite structures, or the like.

The term "superabsorbent particle(s)", "superabsorbent polymer(s)", "SAP" and "superabsorbent polymer particle(s)" are interchangeable and all refer to a superabsorbent material suitable for use in the present disclosure are known to those skilled in the art, and may be in any operative form, such as particulate form and mixtures thereof. Generally stated, the "superabsorbent particles" can be a water-swellable, generally water-insoluble, hydrogel-forming polymeric absorbent material, which is capable of absorbing at least about <NUM>, suitably about <NUM>, and possibly about <NUM> times or more its weight in physiological saline (e.g., saline with <NUM> wt. The superabsorbent material may be biodegradable or bipolar. The hydrogel-forming polymeric absorbent material may be formed from organic hydrogel-forming polymeric material, which may include natural material such as agar, pectin, and guar gum; modified natural materials such as carboxymethyl cellulose, carboxyethyl cellulose, and hydroxypropyl cellulose; and synthetic hydrogel-forming polymers. Synthetic hydrogel-forming polymers include, for example, alkali metal salts of polyacrylic acid, polyacrylamides, polyvinyl alcohol, ethylene maleic anhydride copolymers, polyvinyl ethers, polyvinyl morpholinone, polymers and copolymers of vinyl sulfonic acid, polyacrylates, polyacrylamides, polyvinyl pyridine, and the like. Other suitable hydrogel-forming polymers include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, and isobutylene maleic anhydride copolymers and mixtures thereof. The hydrogel-forming polymers may be lightly crosslinked to render the material substantially water insoluble. Crosslinking may, for example, be by irradiation or covalent, ionic, Van der Waals, or hydrogen bonding. The superabsorbent material may suitably be included in an appointed storage or retention portion of the absorbent system and may optionally be employed in other components or portions of the absorbent article. The superabsorbent material may be included in the absorbent layer or other fluid storage layer of the absorbent article of the present invention in an amount up to <NUM>% by weight. Typically, the superabsorbent material, when present, will be included in an amount of from about <NUM>% to about <NUM>% by weight, based on the total weight of the absorbent layer. In addition, "superabsorbent particles", "superabsorbent polymer particles" or "SAPs" refer to water-swellable, water-insoluble organic or inorganic materials capable, under the most favorable conditions, of absorbing at least about ((<NUM>)) times their weight, or at least about <NUM> times their weight, or at least about <NUM> times their weight in an aqueous solution containing <NUM> weight percent sodium chloride. In absorbent articles, such as diapers, incontinent diapers, etc., the particle size is typically ranging between ((<NUM>))<NUM> to <NUM>, preferably between <NUM> to <NUM>, more preferably between <NUM> to <NUM>.

The term "topsheet" refers to a liquid permeable material sheet forming the inner cover of the chassis of an absorbent article and which in use is placed in direct contact with the skin of the wearer. The topsheet is typically employed to help isolate the wearer's skin from liquids held in the absorbent structure. The top sheet can comprise a nonwoven material, e.g., spunbond, meltblown, carded, hydroentangled, wetlaid or any other type of nonwoven.

Embodiments according to the disclosure will now be described. It is understood that technical features described in one or more embodiments may be combined with one or more other embodiments without departing from the intention of the disclosure and without generalization therefrom.

An apparatus <NUM> apparatus suitable for forming moulded absorbent material deposit structures to be used as absorbent cores for absorbent articles is illustrated in <FIG>, or in other words, <FIG> represents a schematic longitudinal cross-sectional view of this apparatus <NUM> for manufacturing a continuous absorbent body. The apparatus <NUM> comprises a forming unit <NUM> and a feeding unit <NUM>. The forming unit <NUM> comprises a rotary forming drum <NUM>, also called a drum former, that rotates in a circumferential direction about an axis <NUM>, and comprises an outer circumferential surface. A plurality of forming pockets <NUM> are arranged on the outer circumferential surface of the forming drum <NUM>. Each forming pocket <NUM> defines a mould cavity where absorbent material is deposited therein thereby forming a moulded absorbent material deposit structure that can be used as an absorbent core for absorbent articles. Each forming pocket <NUM> comprises a mould cavity being bounded by at least one exterior surface, or by a masking component, defining the contour of the absorbent core to be formed and a bottom air permeable base surface. The bottom air permeable base surface comprises a foraminous forming screen, or mesh substrate, adapted to suck air while maintaining, or retaining, the absorbent material deposited from the feeding unit <NUM> thereon. The forming pocket <NUM> can optionally comprise a three-dimensional shaping profile member, or a channel insert, within the mould cavity to form a moulded absorbent material deposit structure, i.e. an absorbent core, with channels. <FIG> illustrates an embodiment of a forming pocket <NUM>, comprising a base <NUM> or frame, supporting a mesh substrate, or foraminous forming screen <NUM>, a masking component <NUM> defining the outer shape of the absorbent core and a channel insert <NUM>. The foraminous forming screen <NUM>, the masking component <NUM> and the channel insert <NUM> defining the mould cavity where the absorbent material is deposited. The absorbent body formed can be continuous or discontinuous depending on the forming pocket <NUM> used, on the absorbent material used, if the absorbent core is wrapped etc..

The absorbent material refers to the material constituting the absorbent core of the absorbent article. Examples of commonly occurring absorbent materials are selected from and not limited to cellulosic fluff pulp, tissue layers, highly absorbent polymers or superabsorbent polymer particles (SAP), absorbent foam materials, absorbent nonwoven materials or the like. For example, the absorbent core comprises cellulosic fluff pulp and/or superabsorbent particles, i.e. SAP.

The feeding unit <NUM> can comprise a defibrating station <NUM> that defibrates a continuous sheet of absorbent material <NUM> such as a sheet of cellulose material into fibers. The defibrating station <NUM> comprises: a defibrating machine <NUM> that defibrates the sheet of absorbent material thereby producing a plurality of absorbent fibers <NUM>, or pulp fibers, or cellulosic fibers, fluff or fluff pulp and a defibration station housing <NUM> that covers the defibrating machine <NUM>. The defibrating station <NUM> can also include a pair of feed rollers <NUM> that supplies the sheet of absorbent material <NUM> to the defibrating machine <NUM>. The defibrating machine <NUM> is a device breaking the absorbent material sheet <NUM> into smaller pieces by grinding, crushing, or cutting, it can be for example a mill such as a hammermill.

The defibrating station <NUM> is connected, meaning fluidically connected, to a discharging conduit <NUM> through which a second airflow <NUM> flows (the first airflow will be mentioned hereunder), in a second airflow direction 24d. The second airflow <NUM> transports the absorbent fibers <NUM> produced in the defibrating station <NUM>, in the discharging conduit <NUM>. In other terms, the absorbent fibers <NUM> are conveyed by the second airflow <NUM> along the discharging conduit <NUM>. The discharging conduit <NUM> corresponds to a channel defined by a housing <NUM> in which the second airflow <NUM> and the absorbent fibers <NUM> flow. In other terms, the housing <NUM> defines an internal or inner volume, i.e. the discharging conduit <NUM>, where the second airflow <NUM> and absorbent fibers <NUM> circulate. The discharging conduit <NUM> fluidically connects the defibrating station <NUM> and the forming unit <NUM>. In particular, the discharging conduit <NUM> comprises at least one inlet fluidically connected to the outlet of the defibrating station <NUM> and the discharging conduit <NUM> comprises at least one outlet fluidically connected to the inlet of the forming unit, meaning that one end of the discharging conduit <NUM> cover the outer peripheral surface of the forming drum <NUM>.

The defibrating station <NUM>, namely the defibrating machine <NUM> generates the second airflow <NUM>. The defibrating machine <NUM> is a device which takes in a sheet of absorbent material <NUM> and shreds it into fibers with a rotating defibrating element <NUM>. The defibrating machine <NUM>, e.g. a hammermill, namely the rotating element, generates an air stream that flows within the discharging conduit <NUM> to the forming drum <NUM>. In other words, the defibrating machine <NUM> generates the second airflow <NUM> with a volumetric flow rate (m<NUM>. s-<NUM>) comprised between <NUM>,<NUM> and <NUM><NUM>. s-<NUM>, preferably between <NUM> and <NUM><NUM>. s-<NUM>, depending on the rotation speed (RPM) of the hammermill that is comprised between <NUM> and <NUM> RPM (rotation per minute), preferably between <NUM> and <NUM> RPM.

The forming drum <NUM> is connected to a suction fan (not shown) through a suction duct (not shown). The suction fan is driven so that the pressure at a prescribed portion inside the forming drum <NUM> is kept negative. A substrate such as a now-woven web, e.g. a core wrap, or absorbent material can be applied on the mesh substrate, or foraminous forming screen, and be maintained on said foraminous forming screen with the negative pressure. The absorbent material such as SAP or fluff is deposited onto said non-woven substrate thereby forming a congregate of absorbent material suitable to be used as an absorbent core for an absorbent article. The absorbent material is maintained on the substrate and/or foraminous forming screen by the negative air-pressure generated by the suction, the pores formed in the mesh substrate functioning, or serving or acting, as suction holes. Moreover, the intake of air from the pores partially generates the second airflow <NUM>. In other words, the suction fan generates a portion of the second airflow <NUM> within the discharging conduit <NUM>, the pulp fibers <NUM> generated by the defibrating machine <NUM> are dispersed within the second airflow <NUM> and are guided to the forming drum <NUM>. The outlet of the discharging conduit <NUM> is arranged in such a way that it covers at least a portion of the outer circumferential surface of the forming drum <NUM> and the forming pockets <NUM> arranged onto the outer circumferential surface of the forming drum <NUM>. The suction fan further promotes the circulation of the second airflow <NUM>. Hence, the absorbent fibers <NUM> are guided by the second airflow <NUM> from the defibrating station <NUM> to the mould cavity arranged within the forming pocket <NUM>. As explained hereabove, the mould cavity comprises a mesh substrate so that the absorbent fibers are retained within the mould cavity to form a moulded absorbent material deposit structure, i.e. an absorbent core, the mesh substrate comprising micro-pores to let air pass through while retaining bigger objects such as fibers or super absorbent particles or a non-woven web.

As explained, hereabove, the absorbent material can also comprise superabsorbent particles (SAP). The absorbent core can comprise a combination of cellulosic fibers, i.e. fluff and superabsorbent particles. The absorbent core can also be essentially fluff-less meaning that the absorbent core contains less than <NUM>% by weight fluff pulp, for example less than <NUM>% fluff pulp, less than <NUM>% fluff pulp or even no fluff pulp, or no more than an immaterial amount of fluff pulp which do not materially affect the thinness, flexibility or absorbency thereof.

As illustrated in <FIG>, the feeding unit <NUM> of the apparatus <NUM> for forming moulded absorbent material deposit structures to be used as absorbent cores for absorbent articles comprises an apparatus suitable for distributing superabsorbent particles homogeneously onto a substrate, this substrate being the mould cavity of a forming pocket eventually already comprising a non-woven fabric arranged on the foraminous forming screen of the forming pocket <NUM>. The apparatus suitable for distributing superabsorbent particles homogeneously onto a substrate comprises a superabsorbent particle discharge pipe <NUM> that supplies superabsorbent particles <NUM> into the discharging conduit <NUM>. More particularly, the discharge pipe <NUM> conveys a stream of superabsorbent particle <NUM> and a first airflow <NUM> to the discharging conduit <NUM>. The discharging conduit <NUM> and the discharge pipe <NUM> are fluidically connected, with the discharge pipe <NUM> extending partially within the discharging conduit <NUM> and comprising an outlet arranged within inner volume of the discharging conduit <NUM>.

As illustrated in <FIG>, the apparatus <NUM> for forming moulded absorbent material deposit structures extends in a longitudinal direction L (length), in a transversal direction T (width) and in a vertical direction V (height).

The discharge pipe <NUM> supplying, or discharging, superabsorbent particles <NUM> can be arranged in the upper part of the discharging conduit <NUM> or alternatively in the lower part of the discharging conduit <NUM> with respect to the vertical direction V. This discharge pipe <NUM> in conjunction with a first airflow <NUM> (<FIG>), which has, or flows in, a first direction, supplies the SAP <NUM> and air into the discharging conduit <NUM>. In other words, the superabsorbent particles <NUM> guided, or transported, in the discharge pipe <NUM> are dispersed within the discharging conduit <NUM> and are guided to the forming drum <NUM>. The discharge pipe <NUM> channels, or conducts, a stream <NUM> comprising superabsorbent particles <NUM> and a first airflow <NUM>. The outlet of the discharging conduit <NUM> is arranged in such a way that it covers at least a portion of the outer circumferential surface of the forming drum <NUM> and the forming pockets <NUM> arranged onto the outer circumferential surface of the forming drum <NUM>. Hence, the superabsorbent particles <NUM> are guided by the first and second airflow <NUM> from a reservoir <NUM> such as a bag or container to the mould cavity arranged within the forming pocket <NUM>. As explained hereabove, the mould cavity comprises a mesh substrate so that the superabsorbent particles <NUM> and/or absorbent fibers <NUM> are retained within the mould cavity to form a moulded absorbent material deposit structure, i.e. an absorbent core, the mesh substrate comprising micro-pores to let air pass through while retaining bigger objects such as fibers and/or super absorbent particles.

<FIG> illustrates a portion of the discharging conduit <NUM> defined by the housing <NUM> and a portion of the discharge pipe <NUM> which partially extends within the discharging conduit <NUM>. The discharging conduit <NUM> comprises here a transversal cross section that is rectangular. The discharge pipe <NUM> comprises a conveying section <NUM> and an outlet section <NUM> comprising an outlet nozzle <NUM>. The outlet nozzle <NUM> comprises a straight portion <NUM> arranged in the continuity of the conveying section <NUM> and a deflecting portion <NUM>. The deflecting portion <NUM> comprises deflecting means <NUM> arranged in a way that only a portion of the stream of superabsorbent particles <NUM> and first airflow <NUM> are deflected and the other portion of said stream of superabsorbent particles <NUM> and first airflow <NUM> is not deflected by the outlet nozzle <NUM>. In other words, the outlet nozzle <NUM> comprises a convergent portion <NUM> and a flat portion <NUM>, the flat portion <NUM> being neither divergent nor convergent.

For sake of clarity, it is to be understood that the discharge pipe <NUM>, in particular the conveying section <NUM>, extends in a longitudinal direction L (length), in a transversal direction T (width) and in a vertical direction V (height), the outlet nozzle <NUM> is arranged in such a way that the straight portion <NUM> extends in the same directions (L,T,V) as the conveying section <NUM> whereas the deflecting portion <NUM> extends in at one in one direction that is not rectilinear to the directions in which the conveying section <NUM> extends in. In other words, the straight portion <NUM> and the conveying section <NUM> extend in a same plane whereas the deflection portion <NUM> and the conveying section <NUM> extend in different planes. According to the embodiment as illustrated in <FIG>, the deflecting portion <NUM> does not extend in the vertical direction or at least does not extend in the same vertical direction as the conveying section <NUM>, or in other words, the deflecting portion <NUM> extends only in a plane defined by the longitudinal and transversal directions unlike the conveying section.

As explained hereabove, the discharge pipe <NUM> conveys a stream <NUM> comprising superabsorbent particles <NUM> and a first airflow <NUM>. As illustrated in <FIG>, with such arrangement, the discharge pipe <NUM>, and specifically the outlet nozzle <NUM> comprises deflecting means <NUM> arranged in a way that only a portion 35a of said stream <NUM> is deflected by the deflecting portion <NUM> and deflecting means <NUM> and the other portion 35b of said stream <NUM> is not deflected, meaning not deflected by the deflecting portion <NUM> and deflecting means <NUM>. Such arrangement enables to create a crossflow between the portion 35a of the stream <NUM> that is deflected and the other portion 35b of the stream <NUM> that is not deflected, an imaginary delimitation 35c between the two portions 35a,35b being represented in <FIG> for illustrative purposes.

The inventors have observed that, surprisingly, such arrangement enables a uniform distribution of the superabsorbent particles <NUM> throughout the mould cavity arranged in the forming pocket <NUM>. Without being bound by theory, it is believed that having the two portions 35a,35b, or two sub-streams 35a,35b, crossing generates a deviation of the superabsorbent particles <NUM> of both first deflected sub-stream 35a and second undeflected sub-stream 35b. This principle is illustrated in <FIG>, in which the discharge pipe <NUM> and namely the conveying section <NUM> conveys, or transports or guides, a stream <NUM> comprising a first airflow <NUM> and superabsorbent particles <NUM>. This stream <NUM> reaching the outlet section, meaning the outlet nozzle <NUM> is divided into two portions, or two sub-streams, 35a,35b : a first portion, or a first sub-stream 35a, comprising a portion of superabsorbent particles 34a, here represented in strips, and a portion of the first airflow 62a and a second portion, or a second sub-stream 35b, comprising a portion of superabsorbent particles 34b, here represented with dots, and a portion of the first airflow 62b. The first portion 35a is deflected by the deflecting means <NUM>, meaning that the superabsorbent particles 34a and first airflow 62a of that first portion 35a have a change of direction or trajectory, e.g. a rebound or a curvature, and exit the discharge pipe <NUM> in a different direction than the second portion 35b. The second portion 35b is not deflected by the deflecting means <NUM>, meaning that the superabsorbent particles 34b and first airflow 62b of that second portion 35b have a laminar flow and go in the same direction as the stream <NUM> in the conveying section <NUM> as illustrated in <FIG>. There is thus a crossflow between the first portion 35a and the second portion 35b at the outlet of the discharge pipe <NUM>. Again without being bound by theory, the first airflow <NUM> comprising a greater volumetric flow rate than the superabsorbent particles <NUM> stream, it is believed that the first airflow 62a of the first portion 35a will deviate the course of the superabsorbent particles 34b of the second portion 35b and the first airflow 62b of the second portion 35b will deviate the course of the superabsorbent particles 34a of the first portion 35a leading to the superabsorbent particles <NUM> having the directions as illustrated in <FIG> and thereby leading to a uniform distribution as illustrated in <FIG>.

It is to be understood that there is a first stream <NUM> of superabsorbent particles <NUM> and first airflow <NUM> flowing, or circulating, within the conveying section <NUM> in the same general direction(s) as the discharge pipe <NUM>, meaning in the same longitudinal and vertical directions, in other words, the first stream <NUM> of superabsorbent particles <NUM> is guided, or conveyed, by the conveying section <NUM>. The superabsorbent particles <NUM> in this first stream <NUM> can be slightly deflected by the walls of the discharge pipe <NUM> but generally flow in the general direction in which the discharge pipe extends in. The first stream <NUM> or superabsorbent particles <NUM> then reaches the outlet section, meaning the outlet nozzle <NUM>, here the first stream <NUM> of superabsorbent particles <NUM> is figuratively divided in two sub-streams or portions, 35a,35b, a first sub-stream 35a, or a first portion 35a of the stream <NUM>, where the superabsorbent particles <NUM> are deflected by the deflecting portion <NUM> comprising deflecting means <NUM> and a second sub-stream 35b, or a second portion 35b of the stream <NUM> where the superabsorbent particles <NUM> are not deflected by the deflecting portion <NUM>. It is to be understood that the superabsorbent particles <NUM> of this first portion 35a are significantly deflected, in other words, the particles are deflected in such a way that they do not flow in the general direction of the discharge pipe <NUM> in particular when exiting the discharge pipe <NUM> through the outlet of said pipe <NUM>. It is also to be understood that the superabsorbent particles <NUM> of this second portion 35b of the stream are not significantly deflected, in other words the superabsorbent particles <NUM> are not deflected or can be partially, or slightly, deflected by the flat, or straight, portion <NUM> in such a way that they flow in the general direction of the discharge pipe <NUM> in particular when leaving the discharge pipe <NUM> through the outlet of said pipe <NUM>. In other words, the first portion 35a of the stream <NUM> has a substantially turbulent flow whereas the second portion 35b of the stream <NUM> has a substantially laminar flow.

It is also to be understood that by promoting a stream of absorbent particles <NUM> and first airflow <NUM> emerging from the discharge pipe <NUM> with a portion 35a that is deflected and a portion 35b that is undeflected, the outlet nozzle <NUM> enables a crossflow of these two portions of stream. This means that these two portions 35a,35b of stream <NUM>, or sub-stream, will intersect, or in other words, there is a point of intersection between the flow direction of the first portion 35a that is deflected and the flow direction of the second portion 35b that is undeflected. Another way to illustrate this, is to represent the flow direction of a portion, or sub-stream, emerging from the outlet nozzle <NUM> (into the discharging conduit <NUM>) by a corresponding vector <NUM>a,<NUM>b. With this representation, it can be said that the outlet nozzle <NUM> enables to have a point of intersection between both vectors.

The deflecting means <NUM> comprise any mean for deflecting the superabsorbent polymer particles <NUM> and first airflow <NUM> flowing within the discharge pipe <NUM>. For example, the discharge pipe <NUM> can comprise an elbow 48a, or a bent section, with a given angle or curvature, as illustrated in <FIG>, or it can comprise a ramp or a plate 48b as illustrated in <FIG>. In other terms, the deflecting means <NUM> comprise an element or a component that is either integral of, meaning constitutive of, the discharge pipe <NUM> or that is arranged within or fixed to the discharge pipe <NUM>. Said deflecting means <NUM> control the flow, speed, direction, mass, shape, and/or the pressure of the stream <NUM> flowing and emerging from the discharge pipe <NUM>. More specifically, the deflecting means <NUM> control the direction and change the trajectory of the superabsorbent particles <NUM> and first airflow <NUM> flowing within the discharge pipe <NUM> and emerging from said pipe <NUM>, namely by partially, or locally, reducing the cross-sectional area of the pipe at the outlet of the discharge pipe <NUM>. The deflecting means <NUM>, for example the elbow 48a, define a first angle α1 between the outlet nozzle <NUM> and the conveying section <NUM> as illustrated in <FIG> or <FIG>. The first angle α1 is obtuse, meaning that is it greater than <NUM>° and less than <NUM>°, preferably the first angle α1 is comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°, more preferably between <NUM>° and <NUM>°, for example <NUM>°. Similarly, the ramp 48b also defines a first angle α1 as described herein between the outlet nozzle <NUM> and deflection portion <NUM> and the conveying section <NUM> as illustrated in <FIG>.

As illustrated in <FIG>, the outlet section, meaning the outlet nozzle <NUM> comprises an inlet 40a, meaning a proximal end, which is coupled, or linked or forms a continuity of matter with, to the conveying section <NUM> of the discharge pipe <NUM>, and an outlet 40b meaning a distal end and also the outlet of the discharge pipe <NUM>, which is arranged inside the discharging conduit <NUM>. The outlet 40b is the frontier between the inner volumes of the discharge pipe <NUM> and the discharging conduit <NUM>. The outlet nozzle <NUM> has a rectangular cross-sectional area along its length and comprises a top wall <NUM> corresponding to the straight or flat portion <NUM>, a bottom wall corresponding to the deflecting portion <NUM> or deflecting means <NUM> and a first and second side wall <NUM>. In other words, the outlet nozzle comprises a rectangular transversal cross section and the cross-sectional area of outlet nozzle is lesser than the cross-sectional area of the conveying section. For example the cross-sectional area of the conveying section is <NUM><NUM> whereas the cross-sectional area of the outlet nozzle <NUM> at the distal end is <NUM><NUM>, or in other words, the cross-sectional area for the passage of the first airflow <NUM> and superabsorbent particles <NUM> is reduced by between <NUM> % and <NUM>%, preferably by between <NUM>% and <NUM>%, for example by <NUM>%. Proximal and distal are used herein in reference to the conveying section <NUM> of the discharge pipe <NUM>, proximal being the point of the outlet nozzle <NUM> closest to the conveying section <NUM> and distal being the point of the outlet nozzle <NUM> farthest from the conveying section <NUM>. The top wall <NUM>, or straight portion <NUM>, comprises a proximal end and a distal end. Both proximal and distal ends of the straight portion <NUM> are aligned with the conveying section <NUM> meaning that these ends are rectilinear with any point of the conveying section <NUM>, meaning defining an angle of <NUM>°. The bottom wall, or deflecting portion <NUM>, comprises a proximal and a distal end. The distal end of the deflection portion <NUM> is unaligned with the bottom wall of the conveying section <NUM>, or in other words, any point of the conveying section, the proximal end and the distal end of the deflection portion <NUM> are not aligned, meaning non-rectilinear thereby defining the angle α1.

Preferably, the distal end of straight portion <NUM> extends beyond the distal end of the deflecting portion <NUM> with respect to the longitudinal direction L as illustrated in <FIG>. As illustrated in <FIG>, the distal end and the proximal end of the deflecting portion <NUM> define a distance D3, D3 is preferably comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>, for example <NUM>. Similarly, the distance between the proximal and distal ends of the deflecting portion <NUM> is preferably greater than the distance between the proximal and distal ends of the straight portion <NUM>. The inventors have observed that such arrangement leads to an good distribution of the superabsorbent particles <NUM> within the mould cavity.

The deflecting means <NUM> are arranged in a way that only a portion of the stream of superabsorbent particle <NUM> and first airflow <NUM> is deflected thereby creating a crossflow between the portion 35a of the stream that is deflected and the portion 35b of the stream that is not deflected by these deflecting means <NUM>. It is thus possible to have an absorbent core where the superabsorbent polymer particles <NUM> are well, i.e. uniformly, distributed across the absorbent core, in particular across the length of the absorbent article.

The feeding unit <NUM> is designed so that the SAP <NUM> supplied by the discharge pipe <NUM> circulate in the discharging conduit <NUM>. The discharge pipe <NUM> extends along the longitudinal and vertical direction L, V with the conveying section <NUM> extending inside and outside of the discharging conduit <NUM>, the outlet nozzle <NUM> being arranged within the discharging conduit <NUM>. The discharge pipe <NUM> and the housing <NUM> of the discharging conduit <NUM> define a second angle α2 as illustrated in <FIG>, more precisely, the lower wall of the discharge pipe <NUM> and the upper wall of the housing <NUM> define said second angle α2. The second angle α2 is acute, meaning that it is comprised between <NUM>° and <NUM>°, preferably the second angle is comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°, for example <NUM>°.

According to an embodiment as illustrated in <FIG>, the deflecting means <NUM>, meaning the lower wall of the outlet nozzle <NUM> extends in a direction, or a plane, substantially parallel to the direction, or plane, of the upper wall of the housing <NUM>. The lower wall of the discharge pipe <NUM>, namely of the conveying section <NUM> defining both angles α1 and α2, the feeding device <NUM> can comprise a discharge pipe <NUM> arranged in a way where the following equation (<NUM>) is respected: <MAT>.

In other words, in an embodiment where the deflection portion <NUM> of the outlet nozzle <NUM> and the upper wall of the housing <NUM> extend in parallel planes defined by the longitudinal and transversal directions L, T, a wall, i.e. the lower wall of the conveying section <NUM>, intersecting both planes, will respect equation (<NUM>). In other terms, the angles α1 and α2 can be complementary.

The feeding unit <NUM> can optionally comprise sealing means <NUM> at the junction between the discharge pipe <NUM> and the housing <NUM> as illustrated in <FIG>. The sealing means <NUM> comprise for example a perforated foam or rubber plate in which the discharge pipe <NUM> goes through, said plate then being associated, or joined, with the housing <NUM>. The sealing means <NUM> can also comprise a metal plate with a through-hole in which the discharge pipe is inserted that is welded onto the housing <NUM> and/or the discharge pipe <NUM>. The sealing means <NUM> can also comprise adjustable stainless-steel plates closing the gap between the housing <NUM> and the discharge pipe <NUM>.

According to an embodiment as illustrated in <FIG>, the feeding unit <NUM> can also comprise a discharge pipe orientation device <NUM> that enables to change the inclination of the discharge pipe <NUM>, or in other words enables to change the value of the second angle α2 between the discharge pipe <NUM> and the housing <NUM>. In other words, the feeding unit <NUM> comprises means to pivot the discharge pipe <NUM> following a pivot direction P. The discharge pipe <NUM> can comprise at least one flexible portion, such as a corrugated plastic pipe connecting two metal pipes, to ease said pivoting. The pipe orientation device <NUM> here comprises a guide <NUM> for example a plate with slots <NUM> extending longitudinally that are either connected altogether through a slot extending vertically or isolated, the discharge pipe <NUM> comprising a pin to be lodged in said slots <NUM>, e.g. a bayonet mount, the pipe orientation device <NUM> can also comprise an actuator (not illustrated) configured to move, preferably induce a movement of rotation and/or translation, the discharge pipe <NUM>, the pipe <NUM> can also be moved manually. Hence with this device <NUM>, it is possible to adjust the second angle (α2) of the discharge pipe <NUM> are readjust, or reposition, the outlet nozzle <NUM> to have a proper distribution of the superabsorbent particles within the forming pocket <NUM>. The pipe orientation device <NUM> can also comprise a visual indicator on the guide <NUM> such as a scale with angles annotated thereby indicating the current value of the second angle α2, the plate with slots <NUM> can be linear or it can be curved or arcuate.

As illustrated in <FIG>, the superabsorbent polymer discharge pipe <NUM> of the feeding unit <NUM> comprises an outlet section <NUM>, meaning an outlet nozzle <NUM>, a conveying section <NUM> as described hereabove, and a venturi section <NUM>. In particular, the discharge pipe <NUM> comprises a first feeding tube <NUM> in which a first airflow <NUM> is flowing, meaning is conveyed. The discharge pipe <NUM> comprises a second feeding tube <NUM> linked to the SAP reservoir <NUM> in which superabsorbent particles <NUM> are flowing, meaning are conveyed. The first and second feeding tubes <NUM>,<NUM> are both fluidically connected to the conveying section <NUM>. The second feeding tube <NUM>, meaning the tube feeding or supplying superabsorbent particles <NUM> to the conveying section <NUM>, penetrates within the first feeding tube <NUM> thereby reducing the cross-sectional area for the passage of air for the first airflow <NUM> and thereby creating a venturi effect. Specifically, the second feeding tube <NUM> by entering the first feeding tube <NUM> and extending partially within said first feeding tube <NUM> creates a constriction in said first feeding tube <NUM> and reduces the air pressure thereby increasing the fluid speed of the first airflow <NUM> past that constriction point. The superabsorbent polymer particles <NUM> are conveyed through the second feeding tube <NUM> mostly via gravity, and then in the conveying section <NUM> via the first airflow <NUM>.

According to an embodiment, the forming unit <NUM> comprises an air-generating device <NUM> able to move air, namely able to blow air within the first feeding tube <NUM>, the first feeding tube <NUM> comprising an inlet fluidically connected to an air- generating device <NUM>. The air-generating device <NUM> is for example a blower or a centrifugal fan as illustrated in <FIG>, but other means of moving air are possible such as an axial fan or more generally any air pump. The air-generating device <NUM> can comprise a housing in which is arranged an impeller moved by a driving mechanism such as a shaft actuated by an electric motor. Said air- generating device <NUM> generates the first airflow <NUM> with a given volumetric flow rate (m<NUM>.

The first and second feeding tube <NUM>,<NUM>, define a third angle α3, particularly, the lower wall of the second feeding tube <NUM> and the upper wall of the first feeding tube <NUM> define this third angle α3. The third angle α3 is preferably acute, meaning that it is comprised between <NUM>° and <NUM>°, preferably the third angle is comprised between <NUM>° and <NUM>°, preferably between <NUM>° and <NUM>°, for example <NUM>°. Such arrangement enables the superabsorbent particles <NUM> to be introduced in the conveying section <NUM> and conveyed by the first airflow <NUM> to the outlet nozzle <NUM> with less turbulence. If the third angle α3 is too low, meaning less than <NUM>°, the SAP will not fall down properly, the SAP will have too much friction with the second feeding pipe <NUM> and gravity cannot ensure a proper conveying of the particles <NUM>, alternatively, if the third angle α3 is greater than <NUM>°, the SAP will end up in the conveying section <NUM> abruptly thereby generating significant turbulences in the stream <NUM>.

According to an embodiment as illustrated in <FIG>, the venturi section <NUM> can comprise an obstacle <NUM> that is arranged in discharge pipe <NUM>, i.e. within the internal volume of said pipe <NUM>, at the junction between the first feeding tube <NUM>, the second feeding tube <NUM> and the conveying section <NUM>. The obstacle <NUM> can be a plate, rib, bloc or any mean that can deviate the first airflow <NUM> and reduce the cross-sectional area of the discharge pipe <NUM> thereby generating a pressure drop and increasing the volumetric flow rate of the first airflow <NUM>. Additionally, the second feeding tube <NUM> can optionally comprise a wall <NUM> partially extending within the first feeding tube <NUM> to further reduce cross-sectional area of the discharge pipe <NUM> and increase the volumetric flow rate of the first airflow <NUM>. Said wall <NUM> can be curved as illustrated in <FIG> or flat (for example as illustrated in <FIG>).

According to an embodiment, the gap defined by obstacle <NUM> and/or wall <NUM> defines a gap comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>, for example with respect to the height of the cross-sectional area of the discharging pipe <NUM> at the venturi section <NUM>. With such gap, the air-generating device <NUM> preferably functions at a rotational speed, or frequency, comprised between <NUM> and <NUM> RPM, for example <NUM> RPM thereby generating a first airflow <NUM> with a speed comprised between <NUM> to <NUM>. s-<NUM> at the inlet of the venturi section <NUM>. The inventors have observed that these parameters lead to an good distribution of the absorbent material.

According to an embodiment, the discharge pipe <NUM> is arranged within the discharging conduit <NUM> so that the distal end of the deflecting portion <NUM> and the upper wall of the housing <NUM> defines a distance D1 with respect to the vertical direction, D1 being comprised between <NUM> and <NUM>. Similarly, the discharge pipe <NUM> is arranged within the discharging conduit <NUM> so that the distal end of the deflecting portion <NUM> and the outer surface of the forming drum <NUM> meaning the forming pocket <NUM>, defines a minimal distance D2 with respect to the longitudinal direction, D2 being comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>. The inventors have observed that these parameters lead to an good distribution of the absorbent material.

With respect to the direction of flow, the discharging pipe <NUM> comprises a first section comprising the first feeding tube <NUM> and the second feeding tube <NUM>, a second section comprising the conveying section <NUM>, a venturi section <NUM> being arranged in-between said first and second sections, and the outlet section or outlet nozzle. These first and second sections can be identical in shape and/or dimension. Alternatively, these first and second sections can be different in shape and/or dimension. For example, the first section can comprise a circular cross section whereas the second section comprises a rectangular cross-section. A transition is made between the circular cross section of the first section and the rectangular cross section of the second section by using curved surfaces that gradually change the shape of the cross section between circle and rectangle, passing continuously through of a plurality of intermediate cross sections of different shapes.

In another embodiment, the apparatus for manufacturing a continuous absorbent body comprises a first covering unit that supplies a first endless substrate precursor, preferably a nonwoven web, that covers the plurality of forming pockets <NUM> of the forming drum <NUM>, before providing the homogeneous mixture of pulp fibers and SAP in the forming pockets <NUM>. After placing the homogeneous mixture of absorbent fibers <NUM> and SAP <NUM> on the first endless substrate precursor, folding guide plates (not shown) fold both lateral sides of the first substrate precursor in the width direction to cover the mixture absorbent fibers <NUM> and SAP <NUM> thereby defining a continuous wrapped absorbent body.

According to an embodiment, instead of comprising folding guide plates, the apparatus for manufacturing a continuous absorbent body comprises a second covering unit that supplies a second endless substrate precursor, preferably a nonwoven web. Said second endless substrate precursor is disposed on the homogeneous mixture of absorbent fibers <NUM> and SAP <NUM> in such a way that said homogeneous mixture is arranged and enveloped between the first and second endless nonwoven substrates thereby defining a continuous wrapped absorbent body.

According to an embodiment as illustrated in <FIG>, the absorbent core can comprise two layers of absorbent material <NUM>,<NUM>. The feeding unit <NUM> comprises in this case two discharging conduits 22a,22b linked to the defibrating station <NUM> (not illustrated). The feeding unit <NUM> comprises two discharge pipes 32a,32b as described herein, each with an outlet nozzle <NUM> as described herein. It this possible to have an absorbent article comprising two layers of absorbent fibers <NUM> and/or superabsorbent particles <NUM>. The two layers can be identical, or they can comprise different amounts of absorbent fibers <NUM> and/or superabsorbent particles <NUM>. For example, if the lower discharge pipe 32a comprises a blower functioning at a lower rotational speed than the blower comprised in the upper discharge pipe 32b, e.g. <NUM> RMP and <NUM> RPM respectively, then the amount of SAP will be lesser in the lower layer of the absorbent core. According to another example, both discharge pipe 32a,32b exploit one air-generating device that is fluidically connected to both pipes, but the venturi section in said pipes is different, e.g. obstacle <NUM> of different dimensions, hence leading also to the layers of the absorbent core having different amount of SAP <NUM>.

According to an embodiment not illustrated, one of the side walls <NUM> of the outlet nozzle <NUM> comprises deflecting means <NUM> as described herein. The deflecting means <NUM> are arranged in a way that only a portion of the stream of superabsorbent particle <NUM> and first airflow <NUM> is deflected thereby creating a crossflow between the portion 35a of the stream that is deflected and the portion 35b of the stream that is not deflected by these deflecting means <NUM>. It is thus possible to have an absorbent core where the superabsorbent polymer particles <NUM> are well, i.e. uniformly, distributed across the absorbent core, in particular across the width of the absorbent article. In this embodiment, the side walls <NUM> both comprise a proximal end and a distal end in reference to the conveying section <NUM>. One first side wall <NUM> comprises both proximal and distal ends aligned with the conveying section <NUM> meaning that these ends of this first side wall <NUM> are rectilinear with any point of the conveying section <NUM>, meaning defining an angle of <NUM>°. The distal end of the other second side wall <NUM> is unaligned, not aligned, with the side wall of the conveying section <NUM>, or in other words, any point of the conveying section <NUM>, the proximal end and the distal end of this other second side wall are not aligned, meaning non-rectilinear thereby defining the angle α1. Preferably, the distal end of first side wall <NUM> extends beyond the distal end of the other second side wall <NUM> with respect to the longitudinal direction L.

According to an embodiment not illustrated, one of the side walls <NUM> of the outlet nozzle comprises deflecting means <NUM> as described herein and the bottom wall <NUM> of the outlet nozzle comprises deflecting means <NUM> as described herein. It is thus possible to have an absorbent core where the superabsorbent polymer particles <NUM> are well, i.e. uniformly, distributed across the absorbent core, in particular across the length and width of the absorbent article.

As mentioned previously, the disclosure also pertains to an apparatus <NUM> suitable for forming moulded absorbent material deposit structures to be used as absorbent cores for absorbent articles, said deposit structures comprising a uniform or homogeneous distribution of superabsorbent particles <NUM>, the apparatus <NUM> comprising:.

According to the present disclosure, the discharge pipe <NUM> extends partially within the discharging conduit <NUM>, the outlet nozzle <NUM> being arranged within the discharging conduit <NUM> in a way that the discharge pipe <NUM> sprays superabsorbent particles <NUM> into the discharging conduit <NUM>, and into the mould cavity of the forming pockets <NUM>.

Incidentally, the outlet nozzle <NUM> feeds the superabsorbent particles <NUM> into the discharging conduit <NUM>, creating a homogeneous mixture of absorbent fibers <NUM> and superabsorbent particles <NUM>, said homogeneous mixture being deposited in the mould cavity, meaning on the foraminous forming screen, of the forming pockets <NUM> arranged on the forming drum <NUM>.

According to an embodiment, the deflection portion <NUM> is oriented substantially parallel to the direction of the first airflow <NUM>.

The method for manufacturing a continuous absorbent core using an apparatus as described herein. For sake of clarity said apparatus comprises: a forming unit <NUM> and a feeding unit <NUM>; the forming unit <NUM> having: a forming drum <NUM> comprising an outer circumferential surface, a plurality of forming pocket <NUM> being arranged on the outer circumferential surface of the forming drum <NUM>, said forming pocket <NUM> comprising a mould cavity defined by a foraminous forming screen and eventually a masking element disposed within the pockets <NUM>; and the feeding unit <NUM> comprising a defibrating station <NUM> with a defibrating machine <NUM>, such as a hammermill, a discharging conduit <NUM> through which a second airflow <NUM> flows, a superabsorbent polymer discharge pipe <NUM> through which a first airflow <NUM> flows comprising an outlet nozzle <NUM> as described herein. The method for manufacturing a continuous absorbent body comprises;.

As written hereabove, according to an embodiment, it is possible to make fluff-less absorbent core, meaning that the hereabove method can only comprise the spraying of superabsorbent particles <NUM> within the mould cavity as described herein.

In an additional embodiment, the method can comprise an additional step, a covering step performed prior to the accumulation step, in which a covering substrate precursor, in other words a core wrap, such as a non-woven material, is applied to cover the mould cavity of forming pockets <NUM>. Subsequently, the accumulation step is carried out where the absorbent material, meaning the absorbent fibers <NUM> and the superabsorbent particles <NUM>, is deposited into the mould cavity and onto the covering substrate precursor. After the accumulation step, a folding step is carried out where the covering substrate precursor is folded over the mixture of pulp fibers and superabsorbent particles <NUM>, thereby defining a wrapped absorbent core. Alternatively, instead of folding over the covering substrate precursor, the method can comprise a second covering step where a second covering substrate, in other words a second core wrap, such as a layer of non-woven material, is applied to cover the mixture of pulp fibers and superabsorbent particles <NUM> thereby defining a wrapped absorbent core.

As seen previously, the forming pocket <NUM> and mould cavity can comprise a channel insert, the method can comprise a further pressing step, where pressing means, such as one or more rollers, apply pressure onto the wrapped absorbent core to ensure that the core wraps are properly joined, or bonded, together at the periphery and/or at the central area thereby ensuring a proper sealing at the periphery and/or ensuring a proper formation of channel(s). Adhesive can be applied on the core warp(s) to strengthen the bonding.

The method can also comprise a removal step, where a surplus of absorbent material can be removed by removal means, such as a brush with bristles or a blower, from the mould cavity and/or channel insert to have a uniform amount of absorbent material in the absorbent cores, said removal step being after the accumulation step and before the covering step.

Claim 1:
Apparatus for distributing superabsorbent particles (<NUM>) onto a substrate, the apparatus comprising a discharge pipe (<NUM>) for conveying a stream (<NUM>) comprising superabsorbent particles (<NUM>) and a first airflow (<NUM>), said discharge pipe (<NUM>) comprising a conveying section (<NUM>) and an outlet nozzle (<NUM>), said outlet nozzle (<NUM>) comprising a straight portion (<NUM>) and a deflecting portion (<NUM>) characterized in that the deflecting portion (<NUM>) comprises deflecting means (<NUM>) arranged in a way that only a portion (35a) of the stream (<NUM>) of superabsorbent particle (<NUM>) and first airflow (<NUM>) is deflected and the other portion (35b) of said stream is not deflected, creating a crossflow between the portion of the said stream (35a) that is deflected and the portion of said stream (35b) that is not deflected.