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Publication numberUS3748693 A
Publication typeGrant
Publication dateJul 31, 1973
Filing dateMar 26, 1971
Priority dateMar 26, 1971
Publication numberUS 3748693 A, US 3748693A, US-A-3748693, US3748693 A, US3748693A
InventorsP Jespersen
Original AssigneeGeorgia Pacific Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus for making nonwoven fibrous webs
US 3748693 A
Abstract
An apparatus wherein a plurality of fibers are transported to and deposited on a foraminous conveyor by a flow of gas to form a nonwoven fibrous web. The passage of the flow through the conveyor is regulated by two independently operable, superposed means for selectively restricting such passage to control the deposition of the fibers on the conveyor and thereby control the thickness of the web.
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I United States Patent 1 1 [111 3,748,693 Jespersen 1 July 31, 1973 APPARATUS FOR MAKING NONWOVEN 2,317,895 4 1943 Drill 19/155 x FIBROUS WEBS 3,501,813 3/1970 Lee et al 19/1563 [75] Inventor: Paul W. Jespersen, Stamford, Conn. FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Georgia-Pacific Corporation, 1,396,985 3/ 1965 France .L 19/1564 Portland, Oreg. Primary Examiner-Dorsey Newton [22] Fned' 1971 Attorney-Birch, Swindler, McKie & Beckett [21] Appl. No.: 128,460

[57] ABSTRACT (SI. An apparatus wherein a plurality of fibers are trans [58] Fie'ld 155 ported to and deposited on a foraminous conveyor by 19/156 5 6 a flow of gas to form a nonwoven fibrous web. The passage of the flow through the conveyor is regulated by [56] References Cited two independently operable, superposed means for selectively restricting such passage to control the depo- UNITED STATES PATENTS sition of the fibers on the conveyorand thereby con- Ct "'01 the thickness of the web 2,890,497 6/1959 Langdon et a1 19/1563 X 2,581,069 1/1952 Bertolet, Jr. 19/ 156.1 3 Claims, 3 Drawing Figures AIR PATENTE JUL3 1 ms INVENTOR PAUL W. JESPERSEN 32 5M4 M, BY

ATTORNEYS tions in thickness.

APPARATUS FOR MAKING NONWOVEN FIBROUS WEBS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to methods and apparatus for making nonwoven webs, and particularly to a method and apparatus for making a nonwoven fibrous web wherein the thickness of the web is accurately controlled, including desired transverse variations in thickness.

2. Description of the Prior Art Various methods and apparatus are known for making nonwoven fibrous webs, including webs adapted to be used as absorbent pads. Exemplary of the prior art methods and apparatus of this general type are those disclosed in Bertolet U.S. Pat. No. 2,581,069, Anderberg et al., US. Pat. No. 3,032,836, Labino U.S. Pat. No. 3,114,939 and Nordstrand US. Pat. No. 3,423,796. The apparatus disclosed in these patents include means for pneumatically depositing a plurality of fibers on a foraminous conveyor and means for controlling the deposition of the fibers, such as a plurality of pivotally mounted vanes positioned adjacent the conveyor. While such vanes are useful for controlling the thickness of the webs, they do not provide sufficient control over the pneumatic deposition means to permit the formation of webs having desired transverse varia- For some uses of nonwoven fibrous webs, it is desirable that the webs have transverse variations in thickness. For example, a web having a central portion of SUMMARY OF THE INVENTION The method and apparatus of. the present invention provide an effective and efficient solution to the abovementioned deficiency of the prior art methods and ap' paratus, and are ideally suited for making nonwoven fibrous webs adapted for use as absorbent pads. Basically described, the apparatus of the invention comprises; a chamber; a foraminous conveyor having a portion extending through the chamber; means for generating a flow of gas through the chamber, said chamber being operable to direct the flow through said conveyor portion; means for feeding a plurality of fibers into the flow so that the fibers are transported to and deposited on said conveyor portion by the flow to thereby form One of the independently operable passage restricting means preferably comprises a plate positioned adjacent the conveyor and having an opening therein. The other independently operable passage restricting means preferably comprises a plurality of movably mounted vanes also positioned adjacent the conveyor. The size and shape of the opening in the plate and the attitude of the vanes may be adjusted independently to produce a web having accurately controlled thickness variations transversely of the web.

The conveyor preferably includes-a wire mesh belt, and the gas flow generating means preferably comprises a conventional blower. The blower preferably is connected to a suction box and the conveyor and passage restricting means preferably extend across the upper end of such box.

The fiber feeding means preferably comprises a pin mill adapted to abrade a sheet of wood pulp. The pin mill preferably is mounted above the suction box so that the pin mill and suction box form a chamber through which an air flow generated by the blower passes. The chamber thus directs the flow through the conveyor and passage restricting means'so that the wood fibers aretransported to and deposited on the conveyor by the flow.

With the foregoing in mind, it is an object of the present invention to provide an improved method and apparatus for making nonwoven fibrous webs.

It is also an object of the inventionto provide a method and apparatus for making nonwoven fibrous trolled by two independently operable, superposed a web; and first and second independently operable, su-

perposed means for adjustably restricting the passage of the flow through said conveyor portion to control the deposition of the fibers on said portion and thereby control the thickness of the web.

Generally described, the method of the invention comprises; directing a flow of gas through a foraminous conveyor; feeding a plurality of fibers into the flow so that the fibers are transported to and deposited on the conveyor by the flow to thereby form a web; and regulating the passage of the flow through the conveyor to control the deposition of the fibers thereon and thereby control the thickness of the web, said regulating including adjusting two independently operable, superposed means for restricting the passage of the flow through the conveyor.

means for restricting the passage of the flow through the conveyor. 1

These and other objects of the invention will be apparent upon a consideration of the following" detailed description of the preferred embodiments thereof given in connection with the following drawings, wherein like reference numerals identify like elements throughout.

- BRIEF DESCRIPTION OF 'TI-IEDRAWING FIG. l'is an elevational view, partially in section, of

DESCRIPTION oE THE PREFERRED I l EMBODIMENTS a A preferred embodiment of the apparatus of theinvention is shown in the drawing, as designated by reference numeral 10. Apparatus 10 includes a pin mill 12 comprising a housing 14, and disposed within the housing, a pair of rotatably mounted feed rolls 16, a rotatably mounted attrition roller 18 and a nose bar 20 positioned between the feed rolls and attrition roller. Feed rolls .16 and attrition roller 18 are rotatably driven by conventional drive mechanisms (not shown). A feed slot 22 is formed in the side of housing 14 adjacent feed rolls 16. Also, a pair of openings 24 are formed in the side of the housing to permit air to enter the housing for a purpose described below, and a pair of windows 26 are mounted on opposite sides of the lower portion of the housing through which the operation of mill 12 may be observed.

A conveyor 28 is mounted below mill 12 and includes a foraminous wire mesh belt 30 and a plurality of rotatably mounted guide rolls 32 about which belt 30 is trained. One of rolls 32 is rotatably driven by a conventional drive mechanism (not shown). The upper run of belt 30 extends across the open lower end of housing 14.

A suction box 34 also is mounted below mill 12. The upper run of belt 30 extends across the open upper end of suction box 34, and the lower end of housing 14 is connected to the upper end of box 34 along the sides of the upper run of belt 30 so that the housing and suction box form a chamber 35 through which the upper run of the belt extends. If desired, a pair of resilient surfaced rollers 36 may be rotatably mounted on the lower end of housing 14 directly above and contacting belt 30 adjacent the entrance and egress of the belt to and from chamber 35. Rollers 36 minimize the flow of air into chamber 35 through the openings provided therein at the juncture of the lower end of housing 14 and upper end of box 34 through which belt 30 extends, for reasons which will become apparent below.

A pair of conduits 38 are connected between the ends of suction box 34 and a conventional blower 40. Blower 40 generates a flow of air through chamber 35 with air being drawn into housing 14 through openings 24 and out of suction box 34 through conduits 38. As will be apparent, the flow moves downwardly from housing 14 and into suction box 34 through the upper run of belt 30.

A rolled sheet 42 of wood pulp is rotatably supported adjacent housing 14. Sheet 42 is fed into the housing through feed opening 22 and between feed rolls 16. Rolls 16 feed the sheet across nose bar 20 and against the surface of attrition roller 18. The attrition roller abrades sheet 42 into individual wood fibers 44 and urges the fibers downwardly into the flow of air through housing 14. Fibers 44 are transported to the upper run of belt 30 and deposited thereon by the air flow, incident to movement of the flow from housing 14 into suction box 34. The fibers thus form a nonwoven fibrous web 46 on the upper run of the belt. Web 46 is thereafter transported out of chamber 35 by belt 30 and deposited on the belt of a transfer conveyor 48.

Apparatus includes means for controlling the thickness of web 46, and in particular for varying the thickness of the web transversely thereof. Such means comprise two independently operable, superposed means for adjustably restricting the passage of the air flow through the upper run of belt 30. One of the passage restricting means comprises a plate 50 positioned beneath the upper run of the belt and having an opening 52 therein. The passage of the air flow though the portion of belt 30 adjacent plate 50 is thus restricted to the area of opening 52.

The other passage restricting means comprises a plurality of movably mounted vanes 54 positioned below plate 50. Vanes 54 preferably are pivotally mounted in the upper end of suction box 34 and extend transversely of belt 30. Vanes 54 may be individually pivoted to differentially restrict the passage of the air flow through the adjacent portion of belt 30.

Plate 50 and vanes 54 permit the thickness of web 46 to be accurately controlled, including variations in the thickness of the web transversely thereof. As mentioned above, this latter feature is particularly advantageous for making webs which are adapted to be used as absorbent pads.

Opening 52 may be of any desired shape and size to provide the desired fiber deposition pattern. The deposition pattern may be further controlled by individually adjusting the attitude of vanes 54.

An example of the combined effects of plate 50 and vanes 54 is illustrated by the embodiment of the apparatus shown in the drawing. In this embodiment, opening 52 extends generally diagonally across plate 50 and is narrower at the ends thereof than at the central portion thereof. Thus, a greater volume of air is permitted to pass through the central portion of the opening than at the ends thereof. Consequently, a greater number of fibers 44 are deposited on the central portion of belt 30 as the belt passes over plate 50 than on the marginal portions of the belt, and the resulting web 46 will have a central portion of greater thickness than the marginal portions. This particular web configuration is well suited for use as an absorbent pad in a disposable diaper.

The deposition of fibers 44 may be further controlled by individually adjusting vanes 54. In the embodiment of the apparatus shown in the drawing, the vanes are all adjusted to the same attitude so that the vanes do not differentially restrict the passage of the air flow through belt 30. However, if a further reduction in the thickness of the marginal portions of web 46 is desired, the vanes which underlie the narrower portions of opening 52 may be partially closed to thereby further restrict the passage of the flow through the adjacent portions-of belt 30. Thus, a still greater number of fibers 44 will be deposited on the central portion of the belt and a lesser number will be deposited on the marginal portions of the belt. Other variations in the size and shape of opening 52 and the attitude of vanes 54 may be employed to provide other transverse variations in the thickness of web 46.

The method of the invention will be apparent from the foregoing description of the apparatus thereof.

The method and apparatus of the invention are effective and economical for making nonwoven fibrous webs, and particularly webs having transverse thickness variations, and thus are ideally suited for making webs adapted to be used as absorbent pads.

While the foregoing constitutes a detailed description of the preferred embodiments of the method and apparatus of the invention it is recognized that various modifications thereof will occur to those skilled in the art. For example, while the preferred embodiment of the apparatus includes a pin mill specifically adapted for feeding a plurality of wood fibers onto belt 30, other fiber feeding means as appropriate for the particular type of fibers desired may be employed. Thus, the invention is to be limited solely by the scope of the appended claims.

. I claim:

1. An apparatus for making non-woven fibrous webs having transverse variations in thickness comprising:

a chamber;

a-foraminous conveyor having a portion extending through said chamber;

means for generating a flow of gas through said chamber, said chamber being operable to direct said flow through said conveyor portion;

means for feeding a plurality of fibers into said flow so that the fibers are transported to and deposited on said conveyor portion by said flow to thereby form a non-woven web;

first means for restricting the passage of said gas flow through said conveyor portion comprising a plate positioned adjacent said conveyor portion on the downflow side thereof and having a generally diagonally extending opening thereacross for the passage of the gas flow therethrough, said diagonal opening is narrower at the ends thereof than the central portion thereof, thereby permitting a conveyor comprises a wire mesh belt.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2317895 *Mar 3, 1941Apr 27, 1943American Rock Wool CorpMeans for and method of manufacturing mineral wool products by the "dry" process
US2581069 *Sep 24, 1945Jan 1, 1952Raybestos Manhattan IncApparatus for producing airlaid fibrous webs
US2648876 *Sep 19, 1950Aug 18, 1953West Point Mfg CoMethod and machine for producing unwoven fabrics
US2890497 *Mar 10, 1954Jun 16, 1959Curlator CorpMachine for forming random fiber webs
US3501813 *Nov 10, 1965Mar 24, 1970Int Paper CanadaMethod of forming a continuous fibrous web
FR1396985A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4223423 *May 12, 1978Sep 23, 1980Foerster John ECotton lint cleaner
US4285647 *Oct 31, 1979Aug 25, 1981American Can CompanyApparatus for the manufacture of fibrous webs
US4482308 *Jan 25, 1983Nov 13, 1984The James River CorporationApparatus for forming dry laid webs
US4627953 *Oct 10, 1984Dec 9, 1986The James River CorporationMethod for forming dry laid webs
US4636159 *Apr 5, 1985Jan 13, 1987Bison-Werke Bahre & Greten Gmbh & Co. KgApparatus for obtaining a predeterminable distribution of weight in the transverse direction of a pre-mat and/or mat
US4701294 *Jan 13, 1986Oct 20, 1987Kimberly-Clark CorporationEductor airforming apparatus
US6330735Feb 16, 2001Dec 18, 2001Kimberly-Clark Worldwide, Inc.Apparatus and process for forming a laid fibrous web with enhanced basis weight capability
US6363580Oct 16, 2000Apr 2, 2002M & J Fibretech A/SSifting net for a fiber distributor
US6499982 *Dec 28, 2000Dec 31, 2002Nordson CorporationAir management system for the manufacture of nonwoven webs and laminates
US6799957 *Feb 7, 2002Oct 5, 2004Nordson CorporationForming system for the manufacture of thermoplastic nonwoven webs and laminates
US6883209 *Jun 16, 2003Apr 26, 2005M & J Fibretech A/SPlant for removing fines from fiber fluff
US7001567Dec 17, 2002Feb 21, 2006Nordson CorporationMelt spinning apparatus and process for making nonwoven webs
US7476350Aug 31, 2004Jan 13, 2009Aktiengesellschaft Adolph SaurerMethod for manufacturing thermoplastic nonwoven webs and laminates
US7947203Feb 11, 2005May 24, 2011Anpap OyProcedure and apparatus in dry forming of fibre layer
US20030085493 *Dec 17, 2002May 8, 2003Nordson CorporationAir management method for the manufacture of nonwoven webs and laminates
US20030147982 *Feb 7, 2002Aug 7, 2003Nordson CorporationForming system for the manufacture of thermoplastic nonwoven webs and laminates
US20030217439 *Jun 16, 2003Nov 27, 2003Andersen Jens Ole BrochnerPlant for removing fines from fiber fluff
US20050023711 *Aug 31, 2004Feb 3, 2005Nordson CorporationMethod for manufacturing thermoplastic nonwoven webs and laminates
US20090078385 *Feb 11, 2005Mar 26, 2009Anpap OyProcedure and apparatus in dry forming of fibre layer
CN105189844A *Apr 28, 2014Dec 23, 2015福尔姆菲贝尔丹麦有限责任公司A method and apparatus for dry-forming a fibrous product
EP0006326A1 *Jun 6, 1979Jan 9, 1980James River-Dixie/Northern Inc.Apparatus for spreading fibres uniformly over a conveyor surface
EP0006327A1 *Jun 6, 1979Jan 9, 1980James River-Dixie/Northern Inc.Apparatus for distributing fibres uniformly over a conveyor surface
EP2799607A1 *May 3, 2013Nov 5, 2014Formfiber Denmark ApSA method and apparatus for dry-forming a fibrous product
WO1999054537A1 *Apr 20, 1999Oct 28, 1999M&J Fibretech A/SSifting net for a fibre distributor
WO2005078193A1 *Feb 11, 2005Aug 25, 2005Anpap OyProcedure and apparatus in dry forming of fibre layer
WO2014177497A1 *Apr 28, 2014Nov 6, 2014Formfiber Denmark ApsA method and apparatus for dry-forming a fibrous product
Classifications
U.S. Classification425/82.1, 19/306
International ClassificationD01G25/00, D04H1/74
Cooperative ClassificationD01G25/00, D21H11/00, D04H1/732
European ClassificationD21H5/26B4