EP1785523A2 - Appareil de séchage à l'air comprenant un support de séchage micropore ayant un profil non circulaire, et processus de séchage de toile associé - Google Patents

Appareil de séchage à l'air comprenant un support de séchage micropore ayant un profil non circulaire, et processus de séchage de toile associé Download PDF

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Publication number
EP1785523A2
EP1785523A2 EP07102122A EP07102122A EP1785523A2 EP 1785523 A2 EP1785523 A2 EP 1785523A2 EP 07102122 A EP07102122 A EP 07102122A EP 07102122 A EP07102122 A EP 07102122A EP 1785523 A2 EP1785523 A2 EP 1785523A2
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EP
European Patent Office
Prior art keywords
micropore
micropore drying
drying
web
drying medium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP07102122A
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German (de)
English (en)
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EP1785523A3 (fr
Inventor
Paul Dennis Trokhan
Donald Eugene Ensign
Michael Gomer Stelljes Jr.
Osman Polat
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Procter and Gamble Co
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Procter and Gamble Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/929,589 external-priority patent/US6434856B1/en
Priority claimed from US09/929,607 external-priority patent/US6473990B1/en
Application filed by Procter and Gamble Co filed Critical Procter and Gamble Co
Publication of EP1785523A2 publication Critical patent/EP1785523A2/fr
Publication of EP1785523A3 publication Critical patent/EP1785523A3/fr
Withdrawn legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
    • D21F11/14—Making cellulose wadding, filter or blotting paper
    • D21F11/145—Making cellulose wadding, filter or blotting paper including a through-drying process
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
    • D21F11/14—Making cellulose wadding, filter or blotting paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F5/00—Dryer section of machines for making continuous webs of paper
    • D21F5/18—Drying webs by hot air
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F5/00—Dryer section of machines for making continuous webs of paper
    • D21F5/18—Drying webs by hot air
    • D21F5/182—Drying webs by hot air through perforated cylinders
    • D21F5/184—Surfaces thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
    • F26B13/10—Arrangements for feeding, heating or supporting materials; Controlling movement, tension or position of materials
    • F26B13/101—Supporting materials without tension, e.g. on or between foraminous belts

Definitions

  • the subject invention relates to through air drying for tissue paper papermaking, and more particularly to through air drying usable with micropore drying media.
  • Micropore drying media are known in the art. Micropore drying media include a ply, or a plurality of plies superimposed in face-to-face relationship. The plies provide restrictions in the flow path for air flow therethrough. The restrictions in the flow path may comprise pores smaller than many of the interstitial areas in tissue paper, as well as other generally planar materials dried, or otherwise made, thereon. The following discussion is directed to tissue paper, it being understood that the invention is not so limited.
  • micropore media suitable for drying tissue paper thereon. Improvements to the micropore media include micropore drying apparatus having multiple zones, high fatigue strength/low pressure drop micropore drying media and micropore media having preferentially reduced wet pressure drop.
  • micropore media suitable for adaptation to the present invention, are illustrated in commonly assigned U.S. Pat. Nos. 5,274,930, issued Jan. 4, 1994 to Ensign et al. ; 5,437,107, issued Aug. 1, 1995 to Ensign et al. ; 5,539,996, issued July 30, 1996 to Ensign et al. ; 5,581,906, issued Dec. 10, 1996 to Ensign et al. ; 5,584,126, issued Dec. 17, 1996 to Ensign et al.
  • micropore drying techniques There remain other ways to optimize energy consumption when using micropore drying techniques. For example, as water is removed from the tissue paper, etc., to be dried by air flow therethrough, subsequent flow restrictions in the micropore media need not be as great. Thus, in the machine direction, flow restrictions in the micropore media may be reduced while maintaining a pore size smaller than many, preferably most, and most preferably all, of the interstices in the tissue paper.
  • tissue paper to be dried travels across the micropore drying medium in the machine direction.
  • This arrangement provides the benefit of decoupling mechanical dewatering of the tissue paper from through air drying of the tissue paper.
  • mechanical dewatering a small pore size is better to promote dewatering by capillary action.
  • pore sizes which are relatively larger, but still provide a limiting orifice for air flow through the tissue paper, have less flow resistance and thereby save energy.
  • Reduced flow resistance through the micropore media may be provided by having pore sizes which successively increase in the machine direction.
  • micropore media having a higher density of pores, i.e., more pores per square centimeter; in the machine direction may be utilized.
  • hybrid media having both of the above features may be utilized.
  • the reduced flow resistance apparatus of the present invention may be used with through air drying tissue paper papermaking processes which are not limited to micropore drying media.
  • the variable flow resistance apparatus and process according to the present invention may be applied to other through air drying tissue paper papermaking techniques as well.
  • the disclosed apparatus and process may be used with the predryers of a through air drying tissue paper papermaking machine.
  • the invention comprises a micropore drying apparatus having a machine direction and a Z-direction orthogonal thereto.
  • the micropore drying apparatus is permeable to air flow therethrough.
  • the micropore drying apparatus has a wet flow resistance to air flow therethrough, which wet flow resistance to air flow decreases in the machine direction of the micropore drying apparatus.
  • the micropore drying apparatus has a grid of pores which provide the air flow therethrough.
  • the wet flow resistance may decrease in either a step wise fashion or in a gradient. The decrease may occur within sections of, or entirely throughout, the drying apparatus.
  • the decreased flow resistance may be achieved by increasing the size and/or number of pores.
  • the decreasing pore resistance may be provided by coating the micropore drying apparatus to reduce the surface energy, or changing the flow path through the pores to be less tortuous and provide a lesser flow resistance in the Z-direction.
  • the hydraulic radius of the pores may be reduced.
  • the micropore drying apparatus 10 comprises at least one, and typically a plurality of, micropore drying media 15.
  • the apparatus 10 is used for drying a web thereon.
  • Each of the at least one micropore drying media 15 preferably comprises one, and preferably a plurality of, plies 22,24,26,28,30,32 superimposed in face-to-face relationship.
  • Such a micropore drying medium 15 is generally planar, and has a Z-direction oriented orthogonal to the plane.
  • the micropore drying apparatus 10 may be executed in a flat geometry or, preferably, is disposed in a curvilinear geometry and adapted to be used in a roll.
  • the apparatus 10 has a machine direction.
  • the web moves in the machine direction relative to the apparatus 10.
  • the micropore drying apparatus 10, and particularly the micropore drying medium 15, have a flow resistance therethrough. The flow resistance varies in a decreasing fashion in the machine direction.
  • a micropore drying apparatus 10 is any apparatus 10 which introduces a micropore drying medium 15 in the flow path of the through air drying process, which micropore drying medium 15 has a field of pores 40 disposed in a grid. A plurality of the pores 40 are smaller than the interstitials of the web to be dried in the through air drying process.
  • a suitable micropore drying apparatus 10 includes a laminate of one or more woven mesh screens, wherein at least one of the woven screens has openings, or pores 40, therethrough which are smaller than the interstitials of the web to be dried thereon.
  • the micropore drying apparatus 10 may be used to dry any web comprising a generally planar sheet material.
  • Webs usable with the micropore drying apparatus 10 include tissue paper 5, synthetic nonwovens, hard grades of paper, cloth, etc. The following description will be directed to a web of tissue paper 5, it being understood that the invention is not so limited.
  • the micropore drying apparatus 10 may comprise a single integral unit.
  • integral unit it is meant that tissue paper 5 disposed on the micropore drying medium 15 of such an apparatus 10 is, or may be, subject to the micropore drying process without substantial interruption during the entire time period the tissue paper 5 is on the micropore drying medium 15.
  • the first ply 22 of the plurality of plies 22, 24, 26, 28, 30, 32 contacts a web of tissue paper 5 disposed thereon.
  • the first ply 22 has pores 40 therethrough, which provide a pore 40 size smaller than at least some of, and preferably smaller than many of, the interstices of the tissue paper 5 disposed thereon.
  • the arrangement having the relatively smaller pore 40 sizes in the first ply 22 provides a limiting orifice for air flow through the first ply 22 and any tissue paper 5 placed thereon. Air may first pass through the tissue paper 5, then through the micropore drying medium 15, vice versa, or a combination thereof as the tissue paper 5 traverses sequentially spaced portions of the micropore drying medium 15.
  • the micropore drying apparatus 10 may comprise a plurality of micropore drying media 15.
  • Subjacent the first ply 22 is preferably a plurality of plies 22, 24, 26, 28, 30, 32 of increasing pore 40 size.
  • five or six plies 22, 24, 26, 28, 30, 32 of increasing pore 40 size may be utilized to form a unitary laminate comprising the micropore drying medium 15.
  • Each successive ply below the first ply 22 provides less flow resistance and increased strength for the laminate comprising the micropore drying medium 15.
  • the pore 40 size under consideration is the finest pore 40 size in the micropore drying medium 15, as this provides the maximum resistance to air flow therethrough and controls the flow of air through the micropore drying medium 15 and any tissue paper 5 disposed thereon.
  • the pore 40 sizes of the subjacent plies 24, 26, 28, 30, 32 may be constant in the machine direction or, preferably, are variable in the machine direction as described hereinbelow.
  • Pore 40 size may be measured using a bubble point test method according to SAE Standard ARP 901, incorporated herein by reference. If the micropore drying medium 15 comprises a laminate of plural plies 22, 24, 26, 28, 30, 32, the micropore drying medium 15 is measured as a unitary laminate. If the micropore drying medium 15 is held stationary, and the web moved relative to the micropore drying medium 15, there are prophetically less fatigue stresses encountered by the micropore drying medium 15.
  • flow resistance measures the wet pressure drop through the micropore drying medium 15.
  • a suitably-sized sample of the micropore drying medium 15 is provided so that a round, 4 inch (10.2 cm) diameter portion of the micropore drying medium 15 may be exposed to flow therethrough.
  • a test fixture is also provided. The test fixture comprises pipe having a length of seven inches (17.8 cm) and a 2 inch (5.1 cm) nominal diameter. The pipe is joined to a reducer.
  • the reducer has a length of 16 inches (40.6 cm) and has a two inch (5.1 cm) nominal inside diameter.
  • the inside diameter of the reducer tapers at a 7° included angle over a 16 inch (40.6 cm) length to a four inch (10.2 cm) nominal inside diameter.
  • the sample of the micropore drying medium 15 is disposed at the four inch (10.2 cm) nominal inside diameter portion of the test fixture.
  • the micropore drying medium 15 is oriented so that the first ply 22 faces the high-pressure (upstream) side of the air flow.
  • the test fixture is symmetrical about the sample of the micropore drying medium 15. Downstream of the sample of the micropore drying medium 15, the test fixture again tapers through a reducer at an included angle of 7° from a four inch (10.2 cm) nominal inside diameter to a two-inch (5.1 cm) nominal inside diameter.
  • This reducer is also joined to a pipe.
  • Such pipe has a length of seven inches (17.8 cm), is straight, and has a two inch (5.1 cm) nominal inside diameter.
  • a spray nozzle is provided and mounted upstream of the sample of the micropore drying medium 15.
  • the spray nozzle is a Spraying System (Wheaton, Illinois) Type TG full cone spray nozzle (1/4 TTG 0.3) with a 0.020 inch (0.05 centimeters) orifice and 100 mesh screen or equivalent.
  • the nozzle is mounted at a distance of 5 inches (12.7 centimeters) upstream of the sample of the micropore drying medium 15.
  • the nozzle supplies 0.06 gallons per minute (227 cubic centimeters per minute) of water at 40 psi (2810 grams per square centimeter) at a 58° full cone spray angle.
  • wet pressure drop is measured at various flow rates. For purposes of determining flow resistance in accordance with the present invention, wet pressure drop is measured at 40 and 80 scfm (18.88 and 37.76 liters per second) per 0.087 square feet (80.8 square centimeters). If the wet flow resistance at either flow rate is less at one point in the machine direction of the micropore drying apparatus 10 than at a preceding section, the wet flow resistance is judged to be less for purposes of the present invention. The wet flow resistance is judged to be less at any point in the machine direction of the micropore drying apparatus 10 if it decreases by at least 5% preferably at least 10% and more preferably at least 20% as measured at any two points spaced apart in the machine direction.
  • the micropore drying medium 15 of the micropore drying apparatus 10 may be stationary, and arranged in a configuration which allows a papermaking belt 7 and web disposed thereon to be moved relative to the stationary micropore drying medium 15.
  • Suitable stationary configurations for micropore drying media 15 include generally cylindrical geometries and geometries having unequal major and minor axes. If the latter arrangement is selected, preferably the major axis MA-MA is greater than the minor axis MI-MI and disposed in a generally vertical orientation.
  • the tissue paper 5 may be carried on a through air drying belt 7. In such an arrangement, the tissue paper 5 is interposed between a movable through air drying belt 7 and a stationary micropore drying medium 15.
  • Suitable papermaking belts 7 include through air drying belts 7 as are well known in the art. Preferred through air drying belts 7 are described in commonly assigned U.S. Pat. Nos. 3,301,746, issued Jan. 31, 1967 to Sanford et al. ; 3,905,863, issued Sept. 16, 1975 to Ayers ; 3,974,025, issued Aug. 10, 1976 to Ayers ; 4,191,609, issued March 4, 1980 to Trokhan ; 4,239,065, issued Dec. 16, 1980 to Trokhan ; 5,366,785 issued Nov. 22, 1994 to Sawdai ; and 5,520,778, issued May 28, 1996 to Sawdai ; 4,514,345, issued April 30, 1985 to Johnson et al.
  • the micropore drying medium 15 according to the present invention may provide for a residence time thereon of at least 1, preferably at least 25, and more preferably at least 250 milliseconds, but not more than 10,000, preferably not more than 5,000, and more preferably not more than 1,000 milliseconds. If desired, the micropore drying medium 15 may comprise multiple zones of differing pressures, as described in the aforementioned patents incorporated herein by reference.
  • the micropore drying medium 15 according to the present invention may have a length ranging from 5 millimeters to 50 meters, with a preferred length of about 4 to about 30 meters, in order to provide adequate residence time.
  • the plies 22, 24, 26, 28, 30, 32 of the micropore drying medium 15 may be joined together to form a unitary support for the tissue paper 5 as follows.
  • the first ply 22 is optionally calendared and the subjacent plies 24, 26, 28, 30, 32 are preferably individually calendared.
  • the calendaring must be sufficient to provide adequate knuckle area for the sintering operation described below.
  • the calendaring must not unduly reduce the open area of the pores 40.
  • the calendaring may reduce the thickness of each ply 22, 24, 26, 28, 30 to approximately 65-85% of its original thickness. A considerable range of calendaring levels may be utilized to provide the desired knuckle area.
  • the plies 22, 24, 26, 28, 30, 32 are then superimposed upon each other in the desired arrangement.
  • the plies 22, 24, 26, 28, 30, 32 are monotonically arranged in order from the smallest pore 40 size to the largest pore 40 size to form a laminate.
  • Table I shows a preferred six-ply arrangement. This arrangement illustrates a preferred embodiment of one laminated micropore drying medium 15 suitable for use as the first micropore drying medium 15 which the tissue paper 5 to be dried encounters during the drying process. TABLE I Ply Warps/Shutes per 2.54 cm for plies 1-5 Perf Plate/Hole Size/Pitch for Ply 6 Warp/Shute diameter (cm) for plies 1-5. Perf Plate Thickness for Ply 6.
  • the micropore drying apparatus 10 may have three sections, each of decreasing flow resistance. Successive sections may be provided with a relatively coarser first ply 22.
  • the second through sixth ply 32 may be the same in all three sections of mutually differing flow resistances.
  • Table IIA below illustrates three different suitable embodiments of the first ply 22. The successive numbers below indicate the successive positions in the machine direction in which the micropore media 15 of the micropore drying apparatus 10 having the specified first ply 22 may be disposed. Position 1 in the Table below precedes Position 2 which precedes Position 3 as the positions are taken in the machine direction. Thus, the tissue paper 5 will encounter positions 1, 2, 3, respectively, in that order.
  • weaves usable in accordance with the first ply 22 of the present invention are shown in Table IIB below.
  • Each of the first ply 22 shown in Table IIB is made with a Dutch Twill weave.
  • TABLE IIB Mesh Count (warps/shutes per 2.54 cm) Pore Density (pores per square centimeter x 10 -5 ) Pore Size (microns) 510 x 3600 7.1 4.5 325 x 2300 2.9 7.5 260 x 2000 2.0 9.3 165 x 1400 0.89 15 130 x 900 0.45 23 80 x 700 0.22 35 24 x 300 0.03 117
  • the micropore drying apparatus 10 may have a pore 40 size which is variable in, and which preferably increases in, the machine direction.
  • the increasing pore 40 size may be provided by having different first ply 22 joined to each other in abutting relationship.
  • the plies 22,24,26,28,30,32 may be sequenced without interruption, except for the means used to sequentially join each first ply 22 to the succeeding plies 24,26,28,30,32.
  • the plies 22,24,26,28,30,32 may be joined together using any known means, including a full penetration tungsten weld or panels bolted into place.
  • first ply 22 may be abutted in end-to-end relationship, with each first ply 22 being joined to subjacent plies 24, 26, 28, 30, 32 as described above.
  • the subjacent plies 24, 26, 28, 30, 32 may be joined together using welding or other means known in the art. If the micropore drying medium 15 is held stationary, by abutting adjacent first ply 22 together with a joining technique which does not involve the first ply 22, interruption in the air flow therethrough, and hence adverse effects on the drying rate can be minimized.
  • a bolted construction can be used instead of a welded construction if the micropore media 15 is held stationary.
  • the micropore drying medium 15 may be movable in the machine direction.
  • the micropore drying medium 15 is disposed as or on the cover of an axially rotatable roll, as is known and illustrated in the art.
  • the axially rotatable roll carries the tissue paper 5 thereon.
  • a through air drying belt 7 thereon.
  • the tissue paper 5 and/or through air drying belt 7 may be utilized.
  • the tissue paper 5 and/or through air drying belt 7 do not move relative to the cover of the axially rotatable roll while it is rotating to minimize tearing of the tissue papers 5.
  • the micropore drying apparatus 10 may comprise two or more discrete units instead of a single integral unit.
  • discrete units it is meant that each unit is, of itself, an integral unit.
  • the two discrete units are mutually separate and spaced apart in the machine direction. At the space between the discrete units, the tissue paper 5 is not subjectable to the micropore drying process.
  • first and second discrete units may be provided. Each discrete unit is spaced apart in the machine direction from the preceding discrete unit. Each successive discrete unit preferably has larger pores 40 than that of the preceding discrete unit.
  • Fig. 3 illustrates a movable micropore drying medium 15.
  • the movable micropore drying medium 15 is in the form of an endless belt comprising a closed loop. Two discrete units are provided.
  • the first discrete unit illustrates the optional through air drying belt 7.
  • the through air drying belt 7 and the first unit of the micropore drying medium 15 are juxtaposed such that the tissue paper 5 to be dried is interposed therebetween.
  • the through air drying belt 7 may further transport the tissue paper 5 to be dried closer to the second discrete unit prior to transfer. Alternatively, and perhaps preferably, the through air drying belt 7 may carry the tissue paper 5 to be dried entirely throughout the second discrete unit of the micropore drying apparatus 10.
  • Fig. 3 having first and second discrete units, may comprise two axially rotatable rolls.
  • the first axially rotatable roll is usable as the first discrete unit, while the second axially rotatable roll is usable as the second discrete unit.
  • Using axially rotatable rolls as the micropore drying apparatus 10 of the present invention provides the benefit of ease of construction and a micropore drying medium 15 which moves in tandem with the tissue paper 5 to be dried.
  • a second micropore drying medium 15 may be disposed in face-to-face relationship with the backside of the through air drying belt 7. This arrangement provides the benefit that the through air drying belt 7 may be separately dewatered, preventing rewet of the tissue paper 5.
  • the pore 40 size may be variable within one or more discrete units of the micropore drying apparatus 10.
  • the largest pore 40 size of a first discrete unit may be matched to, larger than or smaller than the smallest pore 40 size of a second or succeeding discrete unit, and so on.
  • the largest pores 40 of the first discrete unit are slightly smaller than or the same size as the smallest pores 40 of the second discrete unit in order to efficiently remove mechanically bound water. It is to be recognized that variations in both residence time and pore 40 sizes may be utilized with any of the foregoing arrangements.
  • At least one of the discrete units of the micropore drying apparatus 10 may comprise pores 40 which are smaller than the interstices of the tissue paper 5. Further, such pores 40 may have a vacuum applied thereto, which vacuum is provided at a pressure less than the breakthrough pressure of the pores 40.
  • Such a discrete unit may be made according to the teachings of commonly assigned U.S. 4,556,450, issued. 1985 to Chuang et al. , or 5,584,126, issued Dec. 17, 1996 to Ensign et al. , and incorporated herein by reference.
  • the smallest pores 40 of the micropore drying apparatus 10 may range from a lower limit of at least 1, and preferably at least 5 microns to an upper limit of 20, and preferably an upper limit of 10 microns.
  • the largest pores 40 of the micropore drying apparatus 10 according to the present invention may range from a lower limit of at least 20, and preferably at least 30 microns to an upper limit of not more than 120, and preferably not more than 40 microns.
  • the decrease in flow resistance of the micropore drying apparatus 10 which occurs in the machine direction may be provided by increasing the density of the pores 40 in one or more micropore drying media 15.
  • density or pore 40 density it is meant the number of pores 40 through the first, or most restrictive, ply of the micropore drying medium 15 per unit area.
  • the pore 40 density, or number of pores 40 per unit area of micropore drying medium 15 increases at constant pore size, greater air flow will occur for a given area of the micropore drying medium 15 and wet flow resistance will be decreased.
  • the first ply 22 of the micropore drying media 15 may have the pore 40 density and pore 40 size listed in Table III for the first, second and third positions of the first ply 22 of the micropore drying medium 15. TABLE III Position of First Ply Pore Density (pores per square centimeter x 10 -5 ) Pore Size (microns) 1 2.0-7.1 4.5-9.3 2 0.45-2.0 9.3-23 3 0.03-0.45 23-117
  • the mesh count and wire size of such a micropore drying medium 15 may be adjusted to achieve constant pore 40 size.
  • the micropore drying apparatus 10 of the present invention may be utilized for the micropore drying apparatus 10 of the present invention.
  • the positions may be contiguous or may be spaced apart in the machine direction.
  • the wet flow resistance monotonically decreases in each successive section, however, it is possible that in a less preferred embodiment, certain sections may be of increasing wet flow resistance.
  • the sizes of the pores 40 may be optimized relative to the sizes of the interstitials of the low and high density regions of the tissue paper 5.
  • the low density regions have larger sized interstitials than the high density regions.
  • the sizes of the interstitials are distributed in a normal distribution, commonly measured as a pore volume distribution. Pore volume distribution is measured by a Pore Volume Distribution Analyzer, made by TRI of Princeton, New Jersey.
  • a micropore drying apparatus 10 having three sections, each of decreasing flow resistance, may be provided.
  • the pore 40 size of the first ply 22 in the first section may be less than the size of the midpoint of the pore volume distribution of the interstitials of the high density regions in the tissue paper 5.
  • the pore 40 size of the first ply 22 in the second section may range from approximately the size of the midpoint of the pore volume distribution of the interstitials in the high density region to approximately the midpoint of the pore volume distribution of the interstitials of the low density regions.
  • the pore 40 size of the first ply 22 in the third section may approximate the midpoint of the size of the interstitials in the low density region.
  • decreasing flow resistance in the machine direction may be accomplished by providing successive micropore drying media 15 with an intrinsically lesser wet flow resistance.
  • successive micropore drying media 15, or successive portions of a single micropore drying medium 15 may be treated with, or made of, a material having an inherently lesser surface energy.
  • one or more micropore drying media 15, and particularly the surface of the pores 40 which provide the limiting flow path through the micropore drying media 15, may be treated with low surface energy extruded plastics such as polyesters or polypropylenes or the micropore drying medium 15 may be woven from such materials.
  • the micropore drying media 15 may be treated with a dry film uniform coating of silicone. Any means which reduces the flow resistance through the micropore drying medium 15 is considered to be suitable.
  • the first ply 22 of the micropore drying medium 15 may be provided with pores 40 therethrough having a less tortuous flow path.
  • the Z-direction dimension of the pores 40 could become straighter or shorter.
  • the flow resistance through the pores 40 of the first ply 22 may be impacted by the hydraulic radius of the pores 40. As the hydraulic radius of the pores 40 increases, the flow resistance therethrough will likewise decrease.
  • a stationary micropore drying apparatus 10 may have a cover therearound.
  • the cover rotates with, and preferably at the same surface speed as, the tissue paper 5 to be dried thereon. If such a rotatable cover is used, preferably the cover has pores 40 larger than the interstitials in the tissue paper 5 to be dried, so that the flow restriction still occurs at the stationary micropore drying medium 15.
  • This arrangement provides the benefit that, if desired, air flow may be drawn in through the web and into the interior of the micropore drying apparatus 10.
  • the micropore drying apparatus 10 may blow air out through the micropore drying medium 15 and then through the web.
  • the micropore drying medium 15 may be utilized on a roll having a noncircular profile.
  • the profile of the roll is taken orthogonal to the machine direction.
  • the profile of the roll may be flat, elliptical as shown, and have a major axis MA-MA greater than the minor axis MI-MI. If the major axis MA-MA is generally vertically oriented, as illustrated, a smaller footprint will be necessary to accommodate a micropore drying medium 15 of increased residence time.
  • the micropore drying medium 15 having a noncircular profile may be executed in the form of an endless loop and be movable in the machine direction.
  • a roll may be used to lightly press the web against the micropore drying medium 15.
  • a roll to lightly press the web against the micropore drying medium 15 may be disposed at the first zone of the micropore drying apparatus 10, the second zone of the micropore drying apparatus 10, or both. Lightly pressing a web against a roll is generally described in U.S. Pat Nos. 5,598,643 ; 5,701,682 ; and 5,772,845 .
  • a micropore drying apparatus having a machine direction and a Z-direction orthogonal thereto, the micropore drying apparatus being permeable to air flow therethrough, the micropore drying apparatus having a wet flow resistance to air flow therethrough, characterized by: the wet flow resistance to air flow decreasing in the machine direction.
  • a micropore drying apparatus having a Z-direction and a machine direction orthogonal thereto, characterized by the micropore drying apparatus comprising a plurality of micropore drying media having at least a first unit and a second unit discrete therefrom, the second unit being spaced apart from the first unit in the machine direction, each of the first and second units comprising a micropore drying media having pores therethrough each unit having a pore density and having a wet flow resistance to air flow therethrough, wherein the wet flow resistance of the second unit is less than the wet flow resistance of the first unit.
  • the above micropore drying apparatus comprising a first axially rotatable unit and a second axially rotatably unit, each of the first and second axially rotatable units having pores therethrough, each of the first and second units having a respective differential pressure applied across the pores, the differential pressure across the first unit being less than the breakthrough pressure of the pores, the differential pressure across the second unit being greater than the breakthrough pressure of the pores.
  • the step of providing a micropore drying medium comprises providing a micropore drying medium having three different sections, each section having pores therethrough, the pores of each section having a pore size, each section's pore size being greater than that of the immediately preceding section, and wherein the tissue paper has high density regions having interstitials sized in a first normal pore volume distribution and a low density region having interstitials sized in a second normal pore volume distribution wherein the pore size of the first section is less than the midpoint of the pore volume distribution of the high density region of the tissue paper.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Paper (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Drying Of Solid Materials (AREA)
EP07102122A 2001-08-14 2002-08-14 Appareil de séchage à l'air comprenant un support de séchage micropore ayant un profil non circulaire, et processus de séchage de toile associé Withdrawn EP1785523A3 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US09/929,589 US6434856B1 (en) 2001-08-14 2001-08-14 Variable wet flow resistance drying apparatus, and process of drying a web therewith
US09/929,607 US6473990B1 (en) 2001-08-14 2001-08-14 Noncircular drying apparatus
EP02750484A EP1425467B1 (fr) 2001-08-14 2002-08-14 Appareil de sechage a air traversant presentant une resistance variable a l'humidite dans le sens machine, et procede de sechage d'une bande continue avec un tel appareil

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP02750484A Division EP1425467B1 (fr) 2001-08-14 2002-08-14 Appareil de sechage a air traversant presentant une resistance variable a l'humidite dans le sens machine, et procede de sechage d'une bande continue avec un tel appareil

Publications (2)

Publication Number Publication Date
EP1785523A2 true EP1785523A2 (fr) 2007-05-16
EP1785523A3 EP1785523A3 (fr) 2007-05-30

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
EP02750484A Expired - Lifetime EP1425467B1 (fr) 2001-08-14 2002-08-14 Appareil de sechage a air traversant presentant une resistance variable a l'humidite dans le sens machine, et procede de sechage d'une bande continue avec un tel appareil
EP07102122A Withdrawn EP1785523A3 (fr) 2001-08-14 2002-08-14 Appareil de séchage à l'air comprenant un support de séchage micropore ayant un profil non circulaire, et processus de séchage de toile associé

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP02750484A Expired - Lifetime EP1425467B1 (fr) 2001-08-14 2002-08-14 Appareil de sechage a air traversant presentant une resistance variable a l'humidite dans le sens machine, et procede de sechage d'une bande continue avec un tel appareil

Country Status (6)

Country Link
EP (2) EP1425467B1 (fr)
AT (1) ATE376606T1 (fr)
CA (1) CA2452853C (fr)
DE (1) DE60223153T2 (fr)
MX (1) MXPA04001149A (fr)
WO (1) WO2003016620A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106609419A (zh) * 2015-10-23 2017-05-03 特吕茨施勒有限及两合公司 用于对纺织的织物幅面进行热处理的设备

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004044572A1 (de) * 2004-09-15 2006-03-30 Voith Fabrics Patent Gmbh Papiermaschinenbespannung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2200867A (en) * 1987-01-21 1988-08-17 Tamfelt Oy Ab Papermakers felt leaving a smooth surface
WO1999018282A1 (fr) * 1997-10-08 1999-04-15 Scapa Group Plc Tissus industriels ameliores

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5598643A (en) * 1994-11-23 1997-02-04 Kimberly-Clark Tissue Company Capillary dewatering method and apparatus
HUP9901098A3 (en) * 1995-06-07 1999-11-29 Procter & Gamble Multiple zone limiting orifice drying of cellulosic fibrous structures, apparatus therefor, and cellulosic fibrous structures produced thereby
US6021583A (en) * 1997-09-18 2000-02-08 The Procter & Gamble Company Low wet pressure drop limiting orifice drying medium and process of making paper therewith
FI104194B (fi) * 1998-04-28 1999-11-30 Valmet Corp Massan kuivatusosa, menetelmä massan kuivattamiseksi ja massan kuivatuslinja
US6473990B1 (en) * 2001-08-14 2002-11-05 The Procter & Gamble Company Noncircular drying apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2200867A (en) * 1987-01-21 1988-08-17 Tamfelt Oy Ab Papermakers felt leaving a smooth surface
WO1999018282A1 (fr) * 1997-10-08 1999-04-15 Scapa Group Plc Tissus industriels ameliores

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106609419A (zh) * 2015-10-23 2017-05-03 特吕茨施勒有限及两合公司 用于对纺织的织物幅面进行热处理的设备
CN106609419B (zh) * 2015-10-23 2019-01-18 特吕茨施勒有限及两合公司 用于对纺织的织物幅面进行热处理的设备

Also Published As

Publication number Publication date
DE60223153D1 (de) 2007-12-06
WO2003016620A1 (fr) 2003-02-27
CA2452853A1 (fr) 2003-02-27
DE60223153T2 (de) 2008-08-14
CA2452853C (fr) 2008-08-05
MXPA04001149A (es) 2004-05-20
EP1785523A3 (fr) 2007-05-30
ATE376606T1 (de) 2007-11-15
EP1425467A1 (fr) 2004-06-09
EP1425467B1 (fr) 2007-10-24

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