EP0032044B1 - Formage à sec de nappes - Google Patents

Formage à sec de nappes Download PDF

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Publication number
EP0032044B1
EP0032044B1 EP80304688A EP80304688A EP0032044B1 EP 0032044 B1 EP0032044 B1 EP 0032044B1 EP 80304688 A EP80304688 A EP 80304688A EP 80304688 A EP80304688 A EP 80304688A EP 0032044 B1 EP0032044 B1 EP 0032044B1
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EP
European Patent Office
Prior art keywords
forming
screen
air
fibres
web
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EP80304688A
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German (de)
English (en)
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EP0032044A1 (fr
Inventor
Raymond Chung
James H. Dinius
David W. Appel
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Kimberly Clark Corp
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Kimberly Clark Corp
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Publication of EP0032044A1 publication Critical patent/EP0032044A1/fr
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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
    • D01G99/00—Subject matter not provided for in other groups of this subclass
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
    • D01G25/00—Lap-forming devices not integral with machines specified above

Definitions

  • the present invention relates to a method and apparatus for forming non-woven fabrics and to the products produced thereby suitable for bath tissue or the like to heavier webs suitable for facial tissues, components for feminine napkins, diaper fillers, toweling, wipes, non-woven fabrics, saturating paper, paper webs, paperboard, et cetera.
  • materials suitable for use as disposable tissue and towel products have been formed on paper-making equipment by water-laying a wood pulp fibrous sheet. Following formation of the sheet, the water is removed either by drying or by a combination of pressing and drying. As water is removed during formation, surface tension forces of very great magnitude develop which press the fibers into contact with one another resulting in overall hydrogen bonding at substantially all fiber intersections; and a thin, essentially planar sheet is formed. It is the hydrogen bonds between fibers which provide sheet strength and, such bonds are produced even in the absence of extensive additional pressing.
  • cellulosic sheets prepared by water-laid methods inherently possess very unfavorable tactile properties (e.g., harshness, stiffness, low bulk, and poor overall sotfness) and, additionally, possess poor absorbency characteristics rendering such sheets generally unsuitable for use as sanitary wipes, bath and facial tissues, and toweling.
  • water-laid sheets are typically creped from the dryer roll with a doctor blade. Creping reforms the flat sheet into a corrugated-like structure, thereby increasing its bulk and simultaneously breaking a significant portion of the fiber bonds, thus artificially improving the tactile and absorbency properties of the material. But creping raises several problems. Conventional creping is only effective on low basis weight webs (e.g., webs having basis weights less than about 15 Ibs./2880 ft. 2 or 25 g/m 2 ), and higher basis weight webs, after creping, remain quite stiff and are generally unsatisfactory for uses such as quality facial tissues.
  • basis weight webs e.g., webs having basis weights less than about 15 Ibs./2880 ft. 2 or 25 g/m 2
  • higher basis weight webs, after creping remain quite stiff and are generally unsatisfactory for uses such as quality facial tissues.
  • Air forming of wood pulp fibrous webs has been carried out for many years; however, the resulting webs have been used for applications where either little strength is required, such as for absorbent products-i.e., pads-or applications where a certain minimum strength is required but the tactile and absorbency properties are unimportant-i.e., various specialty papers.
  • a second type of system for forming air-laid webs of dry cellulosic fibers which has found limited commercial use has been developed.
  • this system employs a fiber sifting chamber or head having a planar sifting screen which is mounted over a forming wire. Fibers are fed into the sifting chamber where they are mechanically agitated by means of a plurality of mechanically driven rotors mounted for rotation about vertical axes. Each rotor has an array of symmetrical blades which rotate in close proximity to the surface of the sifting screen.
  • the system generally employs two, three or more side-by-side rotors mounted in suitable forming head.
  • the forming head is to be cleared of agglomerated material, it is necessary to remove 10% or more by weight of the incoming material from the forming head for subsequent reprocessing or for use in less critical end products.
  • the separating method used entrains a large number of good fibres with the agglomerates leaving the forming head.
  • the severe mechanical action of the hammermills in the secondary processing system damages and shortens such otherwise good fibres, while breaking up the agglomerates.
  • Another inherent shortcoming of these systems is a tendency to form webs having a non-uniform weight profile across their width. This is a condition which is very difficult to overcome. It is especially troublesome when making webs in the towelling and lightweight tissue ranges.
  • air-forming techniques can be advantageously used in high speed production operations to prepare cellulosic sheet material that is sufficiently thin, and yet has adequate strength, together with softness and absorbency, to serve in applications such as bath tissues, facial tissues and light weight towelling.
  • a method of forming an air-laid web of dry fibres in accordance with the present invention is characterised in that the fibres are not subjected to such cross flow forces as to cause forceful disintegration during their passage through and from the forming head so that a substantially uniform basis weight is maintained in the web in the cross direction throughout the forming process.
  • Apparatus for forming a quality web of air-laid dry fibres on a high speed production basis in accordance with the invention is characterised in that the fibres in the forming head are maintained substantially free of fibre grinding and disintegrating forces; and is characterised by means for continuously separating undesirable fibrous materials delivered to the forming head from the aerated bed and by an enclosed forming zone situated between the forming head and the forming surface for conveying the fibrous material from the forming head through the forming zone to the forming surface in a rapidly moving air stream and for air-laying the individualised fibres and soft fibre flocs on the movable foraminous forming surface so as to form an air-laid web of randomly oriented dry individualised fibres and soft fibre flocs on the surface during movement thereof wherein means are provided substantially to eliminate cross flow forces as the fibrous material passes through the apparatus so that the basis weight of the fibrous material may be maintained substantially constant in the cross direction.
  • an air-laid web of dry fibres is formed from individual fibres and soft fibre flocs conveyed in an air stream through a forming head including a screen onto a relatively moving forming surface characterised in that the fibres are not subjected to such cross flow forces so as to cause forceful disintegration during their passage through and from the forming head so that a substantially uniform basis weight has been maintained in the web in the cross direction throughout the forming process.
  • non dense, rolled up bundle of fibers, often including bonded fibers, having a bulk density greater than .2 grams per cubic centimeter (g/cc.) and which are generally formed by mechanical action during fiber transport or in a rotor chamber where the fibers are commonly, and often intentionally, subjected to mechanical disintegrating action.
  • loc and soft floc are herein used to describe soft, cloud-like accumulations of fibers which behave like individualized fibers in air; i.e., they exhibit relatively high coefficients of drag in air.
  • Basis density is the weight in grams of an uncompressed sample divided by its volume in cubic centimeters.
  • the phrase "2-dimensional" is used to describe a system for forming a web wherein: i1 the cross-section of the system and the flows of air and fiber therein are the same at all sections across the width of the system; and i ll , where each increment of system width behaves essentially the same as every other increment of system width; thereby permitting the system to be scaled up or down to produce high quality webs of any suitable and commercially useful widths on a high-speed production basis and wherein a web's cross-directional profile in terms of basis weight can be controlled and, preferably, can be maintained uniform.
  • coefficient of variation is used herein to describe variations in the cross-directional basis weight profile of both the web being formed and the fibrous materials input to the system, and comprises the standard deviation (u) expressed as a percent of the mean.
  • the coefficient of variation should not vary more than 5% and, preferably, should vary less than 3% in the cross-machine direction.
  • the basis weight profile in the cross-machine direction of the web being formed may, for example, be determined by weighing strips of the web which are three inches (76.2 mm) in width (3" C.D.) by seven inches (177.8 mm) in length (7" M.D.).
  • rate of fiber delivery is intended to mean the mass quantum or weight rate of feed of fibrous materials delivered to the forming head, and may be expressed, for example, in units of pounds per hour per inch of former width (ibs./hr.in.), pounds per minute per foot of former width (lbs./min./ft.), or in any other suitable units.
  • “Throughput” is intended to describe the screening rate for fibrous materials discharged from the forming head-i.e., the mass quantum or weight rate of fiber delivery through the former screen per unit area of screen surface-and may be expressed, for example, in units of pounds per hour per square inch of effective screen surface area (Ibs/hr./in. 2 ).
  • an exemplary system for forming an air-laid web 60 of dry fibers comprising: a fiber metering section, generally indicated at 65; a fiber transport or educator section, generally indicated at 70; a forming head, generally indicated at 75, where provision is made for controlling air and fiber flow, and where individual fibers are screened from undesirable aggregated fiber masses and, thereafter, are air-laid on a foraminous forming wire 80; a suitable bonding station, generally indicated at 85, where the web is bonded to provide strength and integrity; a drying station, generally indicated at 87, where the bonded web 60 is dried prior to storage; and, a take-up or reel-type storage station, generally indicated at 90, where the air-laid web 60 of dry fibers is, after bonding and drying, formed into suitable rolls 95 for storage prior to delivery to some subsequent processing operation (not shown) where the web 60 can be formed into specifically desired consumer products.
  • the forming head 75 includes a separator system, generally indicated at 76, for continuous removal of aggregated fiber masses.
  • a separator system for continuous removal of aggregated fiber masses.
  • Such separated aggregated fiber masses and individualized fibers entrained therewith are preferably removed from the forming area by means of a suitable conduit 77 maintained at a pressure level lower than the pressure within the forming head 75 by means of a suction fan (not shown).
  • the conduit 77 may convey the masses to some other area (not shown) for use in inferior products, for scrap, or, alternatively, the undesirable aggregated fiber masses may be recycled to a hammermill where the masses are subjected to secondary mechanical disintegration prior to reintroduction into fiber meter 65.
  • the forming head 75 also includes a forming chamber, generally indicated at 79, positioned immediately above the foraminous forming wire 80.
  • a forming chamber generally indicated at 79, positioned immediately above the foraminous forming wire 80.
  • a vacuum box 126 positioned immediately below the forming wire 80 and the web forming section 79 serves to maintain a positive downwardly moving stream of air which assists in collecting the web 60 on the moving wire 80.
  • a second supplementary vacuum box 128 may be provided beneath the forming wire at the point where the web 60 exits from beneath the forming chamber 79, thereby insuring that the web is maintained flat against the forming wire.
  • the web 60 is passed through calendar rolls 129 to lightly compact the web and give it sufficient integrity to permit ease of transportation to conveyor belt 130.
  • a light water spray can be applied from nozzles 131 and 135 in order to counteract static attraction between the web and the wire.
  • An air shower 132 and vacuum box 134 serve to clean loose fibers from the wire 80 and thus prevent fiber build-up.
  • the web 60 may be bonded in any known conventional manner such, merely by way of example, as i) spraying with adhesives such as latex, ii) overall calendering to make a saturating base paper ⁇ /.e.,a bulky web with a controlled degree of hydrogen bonding - iii) adhesive print pattern bonding, or other suitable process.
  • adhesives such as latex
  • Such bonding processes do not form part of the present invention and, therefore, are neither shown nor described in detail herein, but, such processes are well known to those skilled in the art of non-woven fabric manufacture. Bonding of the web as by rolls 136 and 138, and drying at 87, may be necessary prior to forming the roll 95.
  • Multiple forming heads 75 may be provided in series in order to increase overall productivity of the system.
  • FIG. 2 there has been illustrated a conventional sifting system of the type described in US­A­4,O ⁇ 4,635 for forming air-laid webs of dry fibers.
  • a hammermill 141 disintegrates fiber provided through conduit 142, the fiber being thereafter conveyed to distributor 148 for distribution onto moving forming wire 80 through screen 150.
  • a plurality of rotating impellers 151 rotate about vertical axes and "sift" the fiber through screen 150. Material to be recycled is removed through conduit 155a to the hammermill 141.
  • pulp or other fibrous material is subjected to intensive mechanical disintegration in hammermill 141, and the resulting individualized fibers, pills and pulp lumps are then fed into the fiber distributor 148 where they are subjected to severe mechanical agitation by impellers 151.
  • Such mechanical agitation results in stratification of the fibrous materials, with the finer materials said to move downwardly, and the coarser materials rising upwardly where such coarse materials are recycled to hammermill 141 for secondary hammermilling operations.
  • the finer materials include individual fibers, soft fiber flocs and relatively small nits which are mechanically propelled across the surface of and through the perforate bottom wall or screen 150 by the agitating and sifting action provided by the impellers 151. That material passing through the perforate bottom wall or mesh screen 150 is then deposited on the forming wire 80 by means of gravity and the air stream generated by suction box 126 to form an air-laid web 60' of dry fibers.
  • the foregoing sifting system has proven suitable for forming relatively high basis weight webs- e.g., webs having basis weights on the order of 24 lbs./2880 ft. 2 (40.7 g/m 2 ) or greater.
  • extremely high fiber recycle percentages must be maintained when attempting to form webs, particularly when attempting to form relatively light basis weight webs suitable for bath and/or facial tissues.
  • productivity of the fiber distributor is extremely low, and a large percentage of the input fibers are subjected to secondary hammermilling operations which tend to further shorten, curl and otherwise damage the fibers and which require excessive amounts of energy consumption.
  • the rotary sifting action of the impellers 151 tends to roll fibers between the impeller blades and the housing 149 and the screen 150 thus generating a large number of undesired pills which increase the recycle percentage.
  • each distributor lays a very thin layer of fibers on the layer from the preceding distributor.
  • such systems are limited in width and generally have poor cross-directional profiles, poor formation, and low strength due to mechanical damage to the fibers.
  • the flow control and screening arrangement of our apparatus is of the 2-dimensional type employing an elongate rotor housing having a single rotor mounted for rotation about a horizontal axis located above the forming wire 80. Since the process of the present invention is essentially 2- dimensional with no component of flow in the cross-machine direction, it is significantly more manageable and predictable than a sifting type former employing multiple rotors rotating in a horizontal plane about vertical axes, thereby permitting the system to be conveniently and readily scaled up and/or down in width to meet commercial web requirements.
  • feed mat 116 may be formed which meets the preferred conditions of full-width uniformity in terms of the mass quantum of fibers forming the mat and the coefficient of variation of the fibrous materials input to the system.
  • the mat thus formed is then fed into the teeth of lickerin 121 which serves to disaggregate the fibers defining the mat by combing such fibers (along with any pulp lumps, nits and other aggregated fiber masses which are present) out of the mat and feeding such materials directly into a high volume air stream 123.
  • the air-suspended fiber stream is conveyed through a suitable fiber transport duct 170 (Figure 3) from the full-width eductor 70 to a full-width inlet slot 171 formed in the upper surface of, and extending fully across, a generally cylindrical housing 172 which here defines the 2-dimensional flow control, screening and separating zone 75.
  • a suitable fiber transport duct 170 ( Figure 3) from the full-width eductor 70 to a full-width inlet slot 171 formed in the upper surface of, and extending fully across, a generally cylindrical housing 172 which here defines the 2-dimensional flow control, screening and separating zone 75.
  • the exemplary duct 170 is preferably subdivided into a plurality of side-by-side flow channels separated by partitions 174 extending the full length of the duct.
  • the desired coefficient of variation constraint in the web being formed can be obtained by spacing the partitions 174 apart by approximately four inches (10 cm) so as to form a plurality of adjacent flow channels extending across the full axial length of housing 172. It has also been found that a partitioned duct arrangement of the type shown in Figure 3 can be advantageously used to accommodate width differences between the feed mat 116 formed in the fiber metering section 65 and the final air-laid web 60 deposited on the foraminous forming wire 80. For example, excellent results have been obtained when attempting to form a web 60 forty-eight inches (1.22 rn) in width, utilizing a feed mat 116 only forty inches (1.02 m) in width.
  • air-suspended fibrous material introduced radially into housing 172 through inlet slot 171 are conveyed by co-action of the air stream and the rotor assembly 175 through the housing 172 for controlled and selective discharge either a) through a full-width discharge opening, generally, indicated at 178 in Figure 3, and into forming zone 79 for ultimate, air-laid deposition on forming wire 80 or, alternatively, b) through a full-width tangential separator slot 179 formed in housing 172 downstream of the discharge opening 178.
  • the separator slot 179 which here forms part of the separation and/or recycle zone 76 ( Figures 1 and 3), is preferably on the order of from 3/16" (4.8 mm) to 3/8" (9.5 mm) in circumferential width when working with wood fibers and, if desired, may be adjustable in any conventional manner (not shown) so as to permit circumferential widening or narrowing of the slot 179 to optimize separation conditions.
  • screening means 180 To permit controlled, selective discharge of individualized fibers and soft fiber flocs through opening 178 and into forming zone 79, while at the same time precluding discharge of nits and other undesired aggregated fiber masses therethrough, suitable screening means, generally indicated at 180 in Figure 3, is mounted within discharge opening 178.
  • Such screening means 180 may simply take the form of a conventional woven square-mesh wire screen of the type shown at 180A in Figure 4 and having openings sized to preclude passage of aggregated fiber masses 195 provided that the screen openings do not exceed 0.1" (2.54 mm) open space from wire-to-wire in at least one direction and have between 38% and 46% open area.
  • screening means 180 is formed with the same radius of curvature as the semi-cylindrical portion of housing 172 within which discharge opening 178 is formed.
  • rotor assembly 175 comprises a plurality of transversely extending rotor bars 181, each fixedly mounted on the outer periphery of a plurality of closely spaced spiders 182 mounted on a shaft 176.
  • the bars 181 move through the radially entering stream of air-suspended fibers entering at inlet slot 171.
  • the air and fibers tend to move outwardly towards the wall 189 of housing 172, thus best illustrated at 186 in Figure 6.
  • Such annular aerated bed 186 of fibrous materials is believed to be on the order of one-half inch (12.7 mm) to one and one-half inches (38.1 mm) thick (dependent upon actual operating parameters), and is believed to be moving rotationally at about half the speed of the rotor bars 181.
  • the rotor assembly 175 is preferably designed a) to minimize pumping action which tends to reduce the relative speed differential between the rotor bars 181 and the aerated bed 186, thus causing the fibers to move over and beyond the screening means 180, and b) so as to minimize mechanical action between the rotor bars 181 and both the housing 172 and screening means 180, which action tends to disintegrate fibers and aggregated fiber masses carried in the air stream and to general pills.
  • the rotor bars 181 are on the order of 3/4" (19 mm) in radial height by 3/8" (9.5 mm) in thickness, and are mounted so as to provide a clearance between the outer edges of the bars 181 and the inner wall surface of the housing 172 and screening means 180 of from 0.10 inches (2.54 mm) to 0.25 inches (6.35 mm) and, preferably, from 0.18 inches (4.57 mm) to 0.20 inches (5.08 mm). To avoid generation of cross-flow forces, it is important that the rotor bars 181 are continuous, extend the full width of the rotor chamber, and are oriented parallel to the axis of the rotor assembly 175.
  • the aerated bed-which contains individualized fibers, soft fiber flocs, nits and other aggregated fiber masses-passes over the screening means 180 some, but not all, of the individualized fibers and soft fiber flocs pass through the screening means into the forming zone 79, while the balance of the individualized fibers and soft fiber flocs, together with nits and other aggregated fiber masses, pass over the screen without exiting from the rotor housing 172.
  • Separation of undesired nits and aggregated fiber masses from individualized fibers and soft fiber flocs is accomplished with a full-width classifying air jet 194, provided upstream of the separator slot 179 and downstream of screening means 180; such air jet being positioned to introduce a full-width air stream generated by any conventional source (not shown) radially into rotor housing 172 just ahead of the separator slot 179.
  • the positive classifying air stream introduced radially into housing 17-2 through air jet 194 tends to divert individualized fibers and soft fiber flocs within the aerated bed 186 radially inward as a result of the relatively high drag coefficients of such materials and their relatively low bulk density (which is generally on the order of less than .2 g./cc.). Since the nits and aggregated fiber masses have a relatively high bulk density in excess of .2 g./cc. and relatively low drag coefilcients, the classifying air stream introduced through the full-width air jet 194 does not divert such materials to any significant extent and, therefore, such undesired materials tend to be centrifugally expelled through the tangential separator slot 179.
  • classifying air through the full-width classifying air jet 194 into housing 172 at pressures on the order of from 30" to 100" H 2 0 (75 to 250x 10 z N/m 2 and at volumes ranging from 1.5 to 2.5 ft.3/min./in. (0.019-0.028 m 3 /min/cm is adequate for deflecting a significant portion of the individualized fibers and soft fiber flocs.
  • the energy level of the classifying air jet is most conveniently controlled by adjusting its pressure.
  • the present invention has thus far been described in connection with the use of a conventional woven square-mesh screen 180A ( Figure 4) for the screening means 180 shown diagrammatically in Figure 3, it is preferred that the screening means 180 take the form of a high capacity slotted screen 180B ⁇ e.g., of the type shown in Figure 5.
  • a slotted type screen 180B with a 2-dimensional rotor assembly 175 mounted for rotation about a horizontal axis it has been found essential that the screen slots be oriented with their long dimensions parallel to the axis of the rotor assembly.
  • the exemplary system herein described has eight rotor bars 181.
  • the number and/or shape of the rotor bars may be varied, provided that such modifications are consistent with mechanical stability and low rotor "pumping" action. That is, the rotor assembly 175 must be dynamically balanced assembly and, therefore, it must include at least two rotor bars. However it will be appreciated that it can include fewer or more than the eight bars illustrated in Figures 1 and 3-for example, excellent results have been achieved with a 4-bar rotor assembly.
  • n rotor bars where n equals any whole integer greater than "1 "-and the shape of the rotor bars are such that pumping action is minimized. Otherwise, the rotor assembly 175 will tend to sweep the aerated fiber fed 186 over and beyond the screening means 180 rather than permitting and, indeed, assisting fiber movement through the screening means.
  • the rotor bars 181 need not be rectangular in cross-section. Rather, they can be circular, vane- shaped, or of virtually any other desired cross-sectional configuration not inconsistent with the object of minimizing rotor pumping action.
  • the air/fiber stream exiting from housing 172 through screening means 180 does not exit radially but, rather, at an acute angle or along chordal lines or vectors which, on average, tend to intersect a line tangent to the mid-point of the screening means 180 at an included angle a.
  • the screening means 180 covers an arc of approximately 86° and, where an 8-bar rotor is being operated at a rotor speed on the order of 1400-1450 RPM, it has been found that the angle a is generally on the order of 11 1°.
  • the forming zone 79 is preferably provided with sidewalls (a portion of one such sidewall is shown at 199 leaving housing 172 at 198 in Figure 3), a full-width downstream forming wall 200, and a generally parallel full-width upstream forming wall 201, which are respectively connected to rotor housing 172 at the downstream and upstream edges of screening means 180, and which respectively lie in parallel planes which intersect a line tangent to the mid-point of the screening means 180 at included angles on the order of 11 °.
  • the upstream end of forming wall 201 is bent as indicated at 201 A, 201 B so as to form a shaped portion which generally accommodates the air/fiber flow pattern exiting, the upstream portion of screening means 180.
  • Portion 201 A extends from housing 172 at 180.
  • the walls 199, 200 and 201 serve to enclose the forming zone 79 and to thereby preclude disruption of the air/fiber stream as a result of mixing between ambient air and the air/fiber stream.
  • the enclosed forming zone 79 is preferably maintained at or near atmospheric pressure so as to prevent inrush and outrush of air and to thereby assist in precluding generation of cross-flow forces within the forming zone.
  • angle a can vary with changes in operating parameters such, for example, as changes in rotor RPM.
  • angle ⁇ will generally lie within the range of 5° to 20° and, preferably, will lie within the range of 8° to 15°.
  • the lower edges of forming walls 200, 201 terminate slightly above the surface of foraminous forming wire 80-generally terminating on the order of from one-quarter inch to one and one-quarter inches (6.35-31.75 mm) above the wire.
  • the forming zone is preferably dimensioned so that under normal adjustment of variable system operating parameters, the velocity of the fiber/air stream through the forming zone is at least 20 f.p.s. (6 m.p.s.) and the fibers are capable of traversing the entire length of the forming zone 79 from screen 180 to forming wire 80 in not more than . 1 seconds.
  • Forming wire speed equals 750 f.p.m (229 m.p.m).
  • the volume of air supplied to rotor housing 172-viz., 1,627 ft.3/min. (46.07 m 3 /min) [Eq. III]- is such that a positive pressure of approximately 1.5" H 2 0 (375 N/m 2 ) is maintained within the housing 172. Since the forming zone 79 is maintained at atmospheric pressure, there exists a pressure drop on the order of 1.5" H 2 0 (375 N/m 2 ) across the screening means 180 through which the air-suspended fibers pass.
  • the rotor bars 181 sweep through the aerated bed 186 and across screening means 180, thus causing at least certain of the individualized fibers and soft fiber flocs within the aerated bed 186 to move through the screening means-such air-suspended fibers have a velocity vector normal to the screening means 180 of approximately 18 f.p.s. (5.5 m.p.s.) [Eq. IX] and a composite velocity vector of approximately 82 f.p.s. (25.0 m.p.s.) [Eq. XIV] directed towards screening means 180 at an acute angle-while at the same time, sweeping nits and aggregated fiber masses over and beyond the screening means 180.
  • a negative suction zone of 1.7" H 2 0 (425 N/m 2 ) is generated in the wake of each rotor bar 181, as best illustrated at 204 in Figure 6.
  • Each such negative suction zone extends the full-width of the rotor housing 172 and is parallel to the axis of the rotor assembly 175.
  • the negative suction generated would be on the order of 3.0" H 2 0 (750 N/m 2 ).
  • the negative suction generated is sufficient to momentarily overcome the pressure drop of approximately 1.5" H 2 0 (375 N/m 2 ) across the screening means 180 and, as a consequence, normal flow of the air/fiber stream through screening means 180 ceases momentarily in the region of the screen beneath the negative suction zone 204.
  • the full-width negative suction zones 204 are, of source, also sweeping across the screening means 180 at the same velocity as the rotor bars 181-viz., 150 f.p.s.
  • the rapidly moving spaced full-width lifting forces serve two important functions-viz., the generated lifting forces t1 tend to lift individualized fibers and soft fiber flocs off screening means 180 in the wakes of the rotor bars across the full-width of rotor housing 172, thus preventing layering of fibers on the screen which tends to plug the screen openings and thus inhibits free movement of fibers through the screen; and ii), tend to lift nits and other aggregated fiber masses off the screening means 180 so as to facilitate their peripheral movement over and beyond the screening means and towards the full-width separator slot 179.
  • Such peripheral movement results from the movement of the annular aerated bed 186 and the sweeping action of the rotor bars 181.
  • the fibers are air-laid or deposited on forming wire 80 at the rate of 4.43 Ibs./min. (2.01 kg/min) [Eq. I]-i.e., the difference between the rate of fiber supplied [Eq. II] and the 5% of fibrous materials supplied which are separated and removed through separating slot 1 79-to form web 60.
  • the fibers deposited on the forming wire 80 are held firmly in position thereon as a result of suction box 126 and its associated suction fan and ducting which serve to accommodate and remove the high volume of air supplied.
  • the web 60 deposited on forming wire 80 has more than adequate integrity to permit rapid movement of the forming wire. Indeed, if one desires to further increase productivity, n additional forming heads may be utilized and the speed of foraminous forming wire 80 may be increased by a factor equal to the number of separate forming heads used-e.g., under the assumed operating condition, two heads would permit operation at 1,500 f.p.m. (457 m/min); three heads would permit operation at 2,250 f.p.m. 686 m/min; et cetera.
  • the mass quantum of fibers deposited on the forming wire 80 per unit area of former screen 180 will be on the order of ten times as great as that deposited by conventional prior art sifting heads of the type shown in Figure 2; and, consequently, the forming wire may be operated at speeds considerably in excess of the 1,000 f.p.m. (305 m/min) practical limit experienced with such prior art systems. Indeed, with the present invention, forming wire speed is no longer limited by the speed of web formation but, rather, by the speed of such subsequent processing steps as bonding in the web bonding station 85 ( Figure 1).
  • the rotor assembly 175 may be formed with n rotor bars 181 where n equals any whole integer greater than "1".
  • fiber throughput-a limiting constraint when attempting to maximize productivity- is a function of rotor speed multiplied by the square root of the number of rotor bars employed-i.e., fiber throughput: f(RPMx ⁇ No. of rotor bars 181
  • This relationship will, of course, vary with the particular screen employed; and, has been graphically illustrated in Figure 8 wherein fiber throughput in Ibs./in./hr.
  • the line 209 represents the Regressor, or "line-of-best-fit", from which functional relationships between throughput and rotor speed can be determined when using a coarse wire screen of the type described above.
  • the line 210 represents the same functional relationships when using a fine wire screen of the type described above.
  • the forming system seems to be less tolerant of mismatches between forming air and rotor speed; and, where such mismatches occur, fibers tend to accumulate on the sidewalls 199 of the forming zone 79. This is readily corrected by reducing rotor speed, normally by less than 10%, while maintaining forming air constant.
  • Numerical nit levels range from “0” (“excellent”), to “1” ("good”) to “2” (“adequate”), to "3” (“poor”), to "4" through “6” ("inadequate” to “nonacceptable”).
  • Such numerical ratings are subjective ratings based upon visual inspection of the formed web 60 and subjective comparisons of pre-established standards.
  • Figure 9 also shows that the throughput of the forming system was increased from .62 1bs./hr/in. 2 44 g/hr/cm while at the same time improving web quality from "poor” to "excellent” by increasing the fiber delivered to the system and increasing the percent recycle.
  • a 2-dimensional air-laid web forming system embodying features of the present invention will, when operating at a proper balance of fiber supply, forming air supply, and rotor speed, not only deliver maximum fiber throughput with minimum recycle, but, moreover, will exert a "healing effect" on basis weight non-uniformities entering the forming head 75. That is, the screen 180, when properly loaded with a moving or transient aerated bed 186 of fibers ( Figure 6), acts as a membrane which tends to equalize or even out the passage of fibers through adjacent incremental widths of the screen. Such "healing effect" is only operative over distances of six inches (6") or less.
  • the "healing effect” will tend to reduce the coefficient of variation within a forming head 75 supplied with an air/fiber stream delivered through a partitioned duct 170 of the type shown in Figure 3-viz., the effect of non-uniformities present within each four inch wide segment of the air stream exiting the partitioned duct 170 will tend to be minimized.
  • the "healing effect” will not function to even out gross irregularities in fiber basis weight over a wide expanse of former widths.
  • Tables I and II represent the use of either a one meter prior art system (Table I) or the 2- dimensional system of the present invention having a semi-cylindrical screen 18" in circumferential length (Table II) to form webs having basis weights of 14 Ibs./2880 ft. 2 (23.7 g/m 2 ) (bath tissue), 17 Ibs./2880 ft. 2 (28.8 g/m 2 ) (facial tissue), and 26, 34 and 40 Ibs./2880 ft. 2 (44.1, 57.6 and 67.8 g/m 2 ) (toweling).
  • a system employing four tandem distributor heads is capable of producing webs ranging from 14 to 40 Ibs./2880 ft. 2 (23.7-67.8 g/m 2 ) at forming wire speeds ranging from about 911 f.p.m. (278 m/min) to about 319 f.p.m. (97 m/min)-i.e., four times the anticipated average maximum speeds attainable when using only a single forming head 148.
  • Such a system generally requires four hammermills and all of the attendant peripheral fiber conveying and recycling systems, together with their inherent disadvantages in terms of capital investment, space, and energy consumption requirements.
  • tandem distributor heads are capable of forming webs having basis weights ranging from 26 to 40 lbs./2880 ft. 2 (44.1-67.8 g/m 2 ) suitable for toweling at forming wire speeds respectively ranging from about 981 (299 m/min) to about 638 f.p.m. (194 m/min).
  • a single forming head 75 embodying the features of the present invention-e.g., the type shown in Figures 1 and 3- is capable of producing similar webs having basis weights ranging from 14-40 lbs./2880 ft. 2 (23.7-67.8 g/m 2 ) at forming wire speeds ranging from about 911 f.p.m. (278 m/min) to about 319 f.p.m. (97 m/min)-viz., speeds comparable to the speeds obtainable with a prior system requiring four tandem distributor heads.
  • These realistically attainable forming wire speeds may be doubled, tripled, or even further multiplied by using two, three or more forming heads.
  • each forming head 75 which is capable of delivering in the order of ten times the mass quantum of fibers per square inch (6.45 g/cm) of former screens as can be delivered by a single prior art fiber distributing head 148.
  • Examples I and II (Table III) include the actual operating parameters utilized for formation of the webs of a prior art apparatus and an apparatus of the present invention, respectively.
  • Example II A further interesting comparative analysis may be made between the present invention of Example II and prior art web forming systems exemplified by Example III of Table III, page 36.
  • Example III Table III
  • both processes produced a facial tissue having approximately the same basis weight.
  • the prior art system required two tandem fiber distributor heads-together with the required peripheral hammermills, fiber conveying systems, and fiber recycling systems; as contrasted with Example II wherein the web was formed in accordance with the invention utilizing only a single forming head 75.
  • fiber throughput in the Example II system embodying the invention was 8.7 times that of the Example III prior art system and, consequently, the speed of forming wire 80 was 500 f.p.m.
  • Example III (152 m/min) for Example II as compared to only 250 f.p.m. (76 m/min) for Example III. While the nit level of the Example III web produced by the prior art system was "1.1" ("good") as compared to "2.7” (between “adequate” and “poor") for the web 60 of Example II, it was necessary to recycle 34% of the fibrous material input to the prior art system as contrasted with only 5.6% in the Example II system. A large portion of the recycled material was comprised of good fibers which, when hammermilled with the aggregated fiber masses, are shortened and damaged.
  • Example II When contrasting the operating parameters used to generate the webs of Example II and any of the other Examples, one difference is worthy of mention at this point-viz., the type of screen employed.
  • the single forming head produced significantly higher throughput rates and employed a slotted screen 11 x2.5 having 43.6% open screen area; whereas the other Examples employed woven square-mesh screens 1 Ox 10 or 12x 12.
  • slotted screens produce improved throughput when used with the present invention only when the slots are oriented parallel to the axis of the rotor assembly, such orientation has been found to be not critical when working with prior art forming systems of the type shown in Figure 2.
  • data recorded in experiments using a prior art system with a slotted screen has been used to generate the line 219 in Figure 10.
  • the present invention permits of greater throughput and, therefore, greater productivity, even when using woven square-mesh screens than do the prior art systems when using slotted screens (Cf., lines 216 and 219 in Figure 10).
  • a feed mat such as that shown at 116 in Figure 3 is first conveyed between a pair of full-width compacting rolls 234, 235 which serve to lightly compact the web 116 so as to form a feed mat 236 characterized by its full-width uniformity and having a coefficient of variation of 5% or less.
  • the compacting rolls 234, 235 are hardened steel rolls and are adjusted so as to provide sufficient web compaction to form a feed mat 236 having enough integrity to permit subsequent handling; yet, not sufficient compaction as to cause hydrogen bonding of individual fibers.
  • the lightly compacted feed mat 236 of non-bonded fibers thus formed is fed through a full-width feed inlet 244 radially into rotor housing 172 by means of a feed roll 245.
  • the feed inlet 244 is preferably positioned downstream of air inlet 171 and upstream of discharge opening 178.
  • the arrangement is such that as the feed mat 236 enters housing 172, it radially intersects the aerated bed 186 of fibers which is moving at a relatively high velocity such that the lightly compacted fibers of feed mat 236 are instantaneously and uniformly dispersed into the bed 186 of fibers.
  • the fibrous materials are, thereafter, selectively passed through screening means 180 disposed in outlet 178 or, alternatively, through full-width tangential separator slot 179, in the manner previously described. Those fibers passing through screening means 180 are conveyed through forming zone 79 and are air-laid on foraminous forming wire 80 to form web 60.
  • the lightly compacted feed mat 236 may be tangentially introduced into head 75 in the same position as the mat is feed radially in Figure 11, or the fibers of lightly compacted feed mat 236 may be fed into the lower end of conduit 170 after being opened by a full width lickerin located adjacent conduit 170.
  • the forming surface may take the form of a perforate or foraminous rotatable cylinder provided with an internal vacuum.
  • One or more forming heads 75 could be mounted in series thereon.
  • the forming head 75 may be mounted in any desired configuration above the forming wire 80, i.e. at a 90° angle to that shown in Figure 3, producing a relatively narrow, high basis weight web, at a high forming wire speed.
  • the forming head may likewise be angularly related to the forming wire in any manner producing the basis weight profile desired.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Nonwoven Fabrics (AREA)

Claims (31)

1. Procédé de formation d'un tissu de fibres sèches déposées par l'air comprenant le transport de fibres individuelles et de flocons de fibres molles dans un courant d'air à travers une tête de formation 75 comprenant un écran 180 sur une surface de formation 80 relativement mobile, de.manière à produire un tissu déposé par l'air 60, caractérisé en ce que les fibres ne sont pas soumises à des forces de courant transversal telles qu'il en résulterait une désagrégation violente durant leur passage à travers et à partir de la tête de formation, de telle sorte qu'un poids de base substantiellement uniforme est conservé dans le tissu dans la direction transversale d'un bout à l'autre du procédé de formation.
2. Procédé selon la revendication 1, caractérisé en ce que la matière fibreuse délivrée dans une proportion de 1 à 10% à la tête de formation 75 comme un lit aéré 186, est séparée d'une manière continue sur l'écran 180 et est déchargée de la tête avec les masses de fibres agrégées, y compris celles qui ont une densité de masse au-dessus de 0.2 g/cc de manière à porter au maximum la séparation des masses de fibres agrégées à partir du lit aéré.
3. Procédé selon l'une quelconque des revendications 1 et 2, caractérisé en ce que la vitesse d'écoulement des fibres à travers la tête de formation est dans la gamme de 35.1 g/cm2/hr. à 105.5 g/cm2/hr. à travers une zone de formation 79 fermée, vers la surface de formation 80 conformée comme une surface de formation foraminée.
4. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que la surface de formation 80 conformée comme surface de formation foraminée est entrainée à une vitesse telle que les fibres sont déposées selon un débit produisant un tissu déposé à l'air 60 ayant un poids de base compris entre 22 g/m2 et un excédent de 68 g/m2.
5. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que les matières fibreuses sont des fibres qui sont "déliées" avant d'être délivrées à la tête de formation et qui sont délivrées à la tête de formation en suspension dans un courant d'air dans lequel la proportion d'air par rapport aux fibres est dans la gamme de 12.5 à 37.5 m3/kg, de telle manière que la proportion d'air par rapport aux fibres soit maintenue d'un bout à l'autre de la formation du tissu.
6. Procédé selon l'une quelconque des revendications 1 à 4, caractérisé en ce que les matières fibreuses sèches délivrées à la tête de formation ont la forme d'un tapis d'alimentation légèrement compacté ayant un profil contrôlé dans la direction transversale.
7. Procédé selon la revendication 6, caractérisé en ce que les matières fibreuses dans ledit tapis d'alimentation légèrement compacté sont déliées auparavant au voisinage de la tête de formation et sont ensuite délivrées dans la tête de formation.
8. Procédé selon l'une quelconque des précédentes revendications, caractérisé en ce que les matières fibreuses sont déchargées de la tête de formation à travers un écran à fentes de haute capacité.
9. Procédé selon la revendication 2 et selon l'une quelconque des revendications dépendant de la revendication 2, caractérisé en ce que la décharge du matériau séparé d'une manière continue à partir de la tête 75 est retournée à la tête, après avoir été soumise à une désagrégation mécanique secondaire.
10. Appareil pour former un tissu de qualité à fibres sèches déposées par l'air à une grande vitesse de production comprenant une surface de formation 80 foraminée et mobile, au moins une tête de formation 75 montée sur la surface de formation, des organes pour délivrer les matières fibreuses sèches à la tête de formation 75, des organes 70, 170, 175 pour transporter les matières fibreuses sèches à travers la tête de formation dans un lit aéré 186, se déplaçant rapidement, de fibres individualisées, de flocons de fibres molles et de masses de fibres agrégées, caractérisé en ce que les fibres dans la tête de formation sont maintenues substantiellement exemptes de broyage de fibres et de forces de désagrégation, et caractérisé par un organe 194 pour séparer continuellement les matières fibreuses indésirables délivrées à la tête de formation à partir du lit aéré et par une zone de formation fermée 79 située entre la tête de formation et la surface de formation pour transporter la matière fibreuse de la tête de formation à travers la zone de formation à la surface de formation dans un courant d'air à déplacement rapide et pour déposer par l'air les fibres individualisées et les flocons de fibres molles sur la surface de formation foraminée mobile, de manière à former un tissu déposé par l'air 60 de fibres sèches individualisées orientées au hasard et de flocons de fibres molles sur la surface durant le mouvement de celles-ci, des organes 199, 200, 201 étant prévus substantiellement pour éliminer les forces de courant transversal, de manière que la matière fibreuse passe à travers l'appareil de telle sorte que le poids de base de la matière fibreuse puisse être maintenu substantiellement constant dans la direction transversale.
11. Appareil selon la revendication 10, caractérisé en ce que les organes pour entrainer la surface de formation foraminée peuvent être ajustés de manière à sélectionner une vitesse susceptible de produire un tissu déposé par l'air ayant tout poids spécifique de base désiré dans une gamme comprise entre au moins 22 g/m2 et un excédent de 68 g/m2.
12. Appareil selon l'une quelconque des revendications 10 et 11, caractérisé en ce que la tête de formation comprend un carter allongé ayant une portion de paroi 189 partiellement cylindrique, une entré de fibres 171 de pleine largeur et une première 178 et une seconde 179 ouvertures de décharge de pleine largeur formées dans la portion de paroi partiellement cylindrique, la première ouverture de décharge ayant un écran 180 à fentes partiellement cylindriques qui y est monté, ayant le même rayon de courbure que la portion de paroi partiellement cylindrique, la seconde ouverture de décharge comprenant une fente tengentielle de séparation à pleine largeur, des organes étant prévus pour introduire en continu un courant d'air 123 de grand volume dans le carter.
13. Appareil selon l'une quelconque des revendications 10 à 12, caractérisé en ce que les organes pour transporter les fibres individualisées et les flocons de fibres molles depuis la tête de formation vers la surface de formation mobile comprennent des organes 199, 200, 201 substantiellement parallèles, espacés et à pleine largeur, en amont et en aval pour resserrer le courant air/fibres dans la zone de formation 79 et dont l'organe 200 intersecte une ligne tangente au milieu de l'écran demi-cylindrique 180 avec un angle aigu inscrit (a) dans la gamme de 5° à 20° et les organes 200, 201 intersectant la surface de formation foraminée 80 avec un angle inscrit (13) de 33° environ.
14. Appareil selon la revendication 12, caractérisé en ce que les organes pour transporter les matières fibreuses sèches à travers la tête de formation dans un lit aéré à déplacement rapide, comprennent un groupe rotor 175 ayant n (où "n" correspond à tout nombre entier plus grand que "1") barres allongées de rotor 181 ayant chacune une configuration en coupe transversale permettant de créer une zone de pression négative 204 dans son sillage durant la rotation du groupe rotor et caractérisé en ce que les surfaces extérieures des barres sont espacées intérieurement d'une certain distance entre la portion de paroi 189 partiellement cylindrique et l'écran 180.
15. Appareil selon la revendication 14, caractérisé en ce que la distance entre les surfaces extérieures des barres et la portion de paroi partiellement cylindrique et l'écran est de l'ordre de 2.54 à 6.35 mm.
16. Appareil selon l'une quelconque des revendications 10 à 15, caractérisé en ce que les organes pour éliminer les forces de courant transversal, pour permettre le maintien du quantum contrôlé de la masse de dispersion des fibres dans la direction transversale durant le transit du courant air/fibres à la tête de formation comprennent un conduit ayant une série de cloisonnages séparés s'étendant sur toute la longueur du conduit et qui sépare le conduit en une pluralité de canaux adjacents de courants.
17. Appareil selon la revendication 12, caractérisé en ce qu'un ajutage d'air de distribution à pleine largeur est monté sur la portion de paroi demi-cylindrique en amont de la fente de séparation tangentielle pour introduire un courant d'air de distribution à pleine largeur, radialement dans le carter, de manière à intersecter le lit aéré de matières fibreuses avant le transit du lit aéré après la fente de séparation, afin de détourner une partie substantielle des fibres individualisées et des flocons de fibres molles radialement à l'intérieur, permettant ainsi qui les masses de fibres agrégées soient déchargées d'une manière centrifuge et tangentielle du carter à travers la fente de séparation.
18. Appareil selon la revendication 17, caractérisé en ce que l'air entrant dans le courant d'air de distribution est fourni à une pression dans la gamme de 76,20 mm à 2.54 mm H20.
19. Appareil selon l'une quelconque des revendications 12, 17 et 18, caractérisé en ce que l'écran à fentes est orienté de manière que la longueur de l'écran s'étende longitudinalement à travers le carter allongé.
20. Appareil selon la revendication 19, caractérisé en ce que la dimension de la petite fente dudit écran à fentes définit les ouvertures de l'écran dans la gamme de 0.64 à 5.08 mm en largeur.
21. Appareil selon l'une quelconque des revendications 12, 17 à 20, caractérisé en ce que l'écran à fentes a une surface ouverte de 30% à 55%.
22. Appareil selon l'une quelconque des revendications 10 à 21, caractérisé en ce que les organes 115/120, 244/245 pour délivrer les matières fibreuses sèches à la tête de formation sont tels que les matières sont délivrées sous forme d'un tapis d'alimentation 116,236 à pleine largeur légèrement compacté, lesdits organes comprenant au moins une paire de rouleaux de compactage 115/118, 234/245 coopérant mutuellement.
23. Appareil selon l'une quelconque des revendications 10 à 21 caractérisé en ce que les organes 244,245 pour délivrer les matières fibreuses sèches à la tête de formation sont tels que les matières sont délivrées sous forme de fibres individuelles séparées d'un tapis d'alimentation 236 à pleine largeur, légèrement compacté, la séparation se produisant au voisinage de la tête de formation, lesdits organes comprenant au moins une paire de rouleaux de compactage 234/235 à pleine largeur coopérant mutuellement.
24. Appareil selon la revendication 10, caractérisé en ce que les organes pour transporter les matières de fibres sèches à travers la tête de formation, comprennent au moins un groupe rotor 175 monté avec un carter de rotor 172 partiellement cylindrique, ayant une surface intérieure 189 partiellement cylindrique, un écran 180 partiellement cylindrique formant une continuation de la surface 189, le groupe 175 comprenant aussi des barres de rotor 181 s'étendant à travers la largeur du carter de rotor et montées de manière que les surfaces extérieures de celles-ci soient séparées des surfaces intérieures du carter et de l'écran 189, 180 par un intervalle tel que durant l'opération, les barres du rotor évitent de soumettre les fibres à des forces de courant transversal susceptibles de déterminer une désagrégation violente durant leur passage à travers l'écran.
25. Appareil selon la revendication 24, caractérisé en ce que durant l'opération, les rotors sont commandés à une vitesse telle que soit maintenue une zone 204 de pression négative dans le sillage des barres par rapport à la pression existant sur la surface externe de l'écran, afin de monter les fibres et les agrégats à partir de l'écran immédiatement dans le sillage de chaque barre.
26. Appareil selon l'une quelconque des revendications 24 et 25, caractérisé en ce que la sortie de décharge des agrégats 179 est prévue dans la pleine largeur du carter et tangentiellement à la surface intérieure 189 du carter et caractérisé en ce qu'un ajutage 194 d'air de distribution est prévu entre l'écran et la sortie de décharge des agrégats, l'ajutage étant dirigé durant l'opération de manière à détourner des fibres individualisées et des flocons de fibres radialement vers l'intérieur pour retourner à. l'écran 180.
27. Tissu déposé par l'air de fibres sèches formées de fibres individuelles et de flocons de fibres molles transportées dans un courant d'air à travers une tête de formation 75 comprenant un écran 180 dans une surface de formation 80 relativement mobile, caractérisé en ce que les fibres ne sont pas soumises à des forces de courant transversal susceptibles de déterminer une désagrégation violente durant leur passage à travers et à partir de la tête de formation, de sorte qu'un poids de base substantiellement uniforme soit maintenu dans le tissu dans la direction transversale, au cours du procédé de formation.
28. Tissu selon la revendication 27, caractérisé en ce que 1% à 10% de matières fibreuses délivrées à la tête de formation 75 comme un lit aéré 186, sont continuellement séparés sur l'écran 180 et sont déchargés de la tête avec les masses de fibres agrégées comprenant celles ayant une densité de masse au-dessus de 0.2 g/cc, afin de porter au maximum la séparation des masses de fibres agrégées du lit aéré.
29. Tissu selon la revendication 28, caractérisé en ce que la décharge du matériau continuellement séparé à partir de la tête 75 est retournée à la tête après avoir été soumise à une désagrégation mécanique secondaire.
30. Tissu selon l'une quelconque des revendications 27 à 29, caractérisé en ce que le poids de base du tissu est compris entre au moins 22 g/m2 et un excédent de 68 g/m2.
31. Tissu selon la revendication 30 ayant un coefficient de variation dans la direction transversale dans la gamme de 0 à 5%.
EP80304688A 1979-12-21 1980-12-22 Formage à sec de nappes Expired EP0032044B1 (fr)

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US10614179A 1979-12-21 1979-12-21
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GB2142351A (en) * 1983-06-29 1985-01-16 Copely Dev Ltd Extraction apparatus and method
GB2240789A (en) * 1990-02-12 1991-08-14 Ernst Fehrer Process and apparatus for producing a nonwoven web
WO1999026496A2 (fr) 1997-11-21 1999-06-03 H.F. & Ph. F. Reemtsma Gmbh Filtre biodegradable pour cigarettes
US6434795B1 (en) 1999-06-01 2002-08-20 Asselin Method for controlling the profile of a non-woven lap and related production installation
WO2003039276A1 (fr) 2001-11-05 2003-05-15 Hauni Maschinenbau Ag Filtre multisegments destine a l'industrie du tabac et procede de production associe
WO2003039277A1 (fr) 2001-11-05 2003-05-15 Hauni Maschinenbau Ag Segments de filtres ou filtre pour cigarettes et procede de production associe

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SE464475B (sv) * 1989-09-28 1991-04-29 Ove Ahlstrand Anordning foer att framstaella en materialbana av fibrer

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US2931076A (en) * 1948-11-23 1960-04-05 Fibrofelt Corp Apparatus and method for producing fibrous structures
US2940134A (en) * 1950-09-02 1960-06-14 Weyerhaeuser Co Dry felting apparatus and process
FR2346474A1 (fr) * 1976-04-02 1977-10-28 Kroyer St Annes Ltd Karl Dispositif pour le formage a sec d'une nappe en materiau fibreux ou particulaire
US4169699A (en) * 1978-03-21 1979-10-02 Kimberly-Clark Corporation Apparatus for classifying fibers

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US4176427A (en) * 1978-08-02 1979-12-04 Scott Paper Company Web forming apparatus employing spreading section

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Publication number Priority date Publication date Assignee Title
US2931076A (en) * 1948-11-23 1960-04-05 Fibrofelt Corp Apparatus and method for producing fibrous structures
US2940134A (en) * 1950-09-02 1960-06-14 Weyerhaeuser Co Dry felting apparatus and process
FR2346474A1 (fr) * 1976-04-02 1977-10-28 Kroyer St Annes Ltd Karl Dispositif pour le formage a sec d'une nappe en materiau fibreux ou particulaire
US4169699A (en) * 1978-03-21 1979-10-02 Kimberly-Clark Corporation Apparatus for classifying fibers

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2142351A (en) * 1983-06-29 1985-01-16 Copely Dev Ltd Extraction apparatus and method
GB2240789A (en) * 1990-02-12 1991-08-14 Ernst Fehrer Process and apparatus for producing a nonwoven web
GB2240789B (en) * 1990-02-12 1994-04-20 Ernst Fehrer Apparatus for producing a nonwoven web
WO1999026496A2 (fr) 1997-11-21 1999-06-03 H.F. & Ph. F. Reemtsma Gmbh Filtre biodegradable pour cigarettes
US6434795B1 (en) 1999-06-01 2002-08-20 Asselin Method for controlling the profile of a non-woven lap and related production installation
WO2003039276A1 (fr) 2001-11-05 2003-05-15 Hauni Maschinenbau Ag Filtre multisegments destine a l'industrie du tabac et procede de production associe
WO2003039277A1 (fr) 2001-11-05 2003-05-15 Hauni Maschinenbau Ag Segments de filtres ou filtre pour cigarettes et procede de production associe

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DE3065565D1 (en) 1983-12-15
AU537637B2 (en) 1984-07-05
EP0032044A1 (fr) 1981-07-15
MX158498A (es) 1989-02-08
AU6558280A (en) 1981-06-25

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