US4666647A — Apparatus and process for forming a laid fibrous …

Claim 1

Independent Claim 254 words

A method for forming a fibrous article, comprising the steps of: providing a rotatable cylindrical drum, an outer circumferentially extending cylindrical wall surface of which is comprised of a foraminous forming surface; defining an annular space between said forming surface and an inner ring, which rotates with said forming surface and is capable of passing air therethrough; substantially preventing a circumferential movement of air through said annular space with a plurality of circumferentially spaced, transverse sealing members, said transverse sealing members connected in said annular space in sealing engagement between said inner ring and said forming surface; dividing the interior of said drum into plural arcuate segments with a plurality of radially extending stationary baffles, said arcuate segments defining and communicating with respective differential pressure zones on said forming surface, and said differential pressure zones including a vacuum laydown zone located on a portion of said forming surface over a first of said interior arcuate segments; substantially preventing an intrusion of ambient air around an edge of said baffles with a sealing flange member which contacts said inner ring with a slideable, sealing engagement and which extends axially across a width dimension of said baffle and extends circumferentially with a length at least equal to a circumferential distance between consecutive transverse sealing members; drawing air through the vacuum laydown zone on the forming surface into the first arcuate segment and out of the rotatable drum; and depositing fibers onto said forming surface under the influence of said air drawn through said vacuum laydown zone.

Claim 2

Independent Claim 254 words

A method for forming a fibrous article, comprising the steps of: providing a rotatable cylindrical drum, an outer circumferentially extending cylindrical wall surface of which is comprised of a foraminous forming surface; defining an annular space between said forming surface and an inner ring, which rotates with said forming surface and is capable of passing air therethrough; substantially preventing a circumferential movement of air through said annular space with a plurality of circumferentially spaced, transverse sealing members, said transverse sealing members connected in said annular space in sealing engagement between said inner ring and said forming surface; dividing the interior of said drum into plural arcuate segments with a plurality of radially extending stationary baffles, said arcuate segments defining and communicating with respective differential pressure zones on said forming surface, and said differential pressure zones including a vacuum laydown zone located on a portion of said forming surface over a first of said interior arcuate segments; substantially preventing an intrusion of ambient air around an edge of said baffles with a sealing flange member which contacts said inner ring with a slideable, sealing engagement and which extends axially across a width dimension of said baffle and extends circumferentially with a length at least equal to a circumferential distance between consecutive transverse sealing members; drawing air through the vacuum laydown zone on the forming surface into the first arcuate segment and out of the rotatable drum; and depositing fibers onto said forming surface under the influence of said air drawn through said vacuum laydown zone.

Claim 3

Dependent Claim 61 words

A method as recited in claim 1, further comprising the step of providing a concavely contoured portion in the forming surface, wherein the concavely contoured surface portion is bounded by walls angularly oriented with respect to the plane of the forming surface proximally adjacent the concavely contoured surface portion, to define an included angle therebetween of from about 45° to 68°.

Claim 4

Dependent Claim 18 words

A method according to claim 2, wherein the concavely contoured surface portion is of generally inverted frusto-pyramidal shape.

Claim 5

Dependent Claim 38 words

A method according to claim 3, wherein the concavely contoured surface portion is elongate in shape, and its bounding walls comprise longitudinal side walls and transverse end walls joined at their bottom edges to a base wall member.

Claim 6

Dependent Claim 36 words

A method according to claim 4, wherein the included angles of the longitudinal side walls are between about 55° and 68°, and the included angles of the transverse end walls are between about 45° and 60°.

Claim 7

Dependent Claim 30 words

A method as recited in claim 1, further comprising the step of segregating high and low vacuum zones within said annular space between the inner ring and the forming surface.

Claim 8

Dependent Claim 49 words

A method as recited in claim 6, wherein said high and low vacuum zones are segregated with circumferentially extending, axially spaced sealing members, which are connected in said annular space in sealing engagement with said transverse sealing members to reduce cross flow between said high and low vacuum zones.

Claim 9

Dependent Claim 37 words

A method according to claim 1, further comprising diminishing the pressure differential on a predetermined portion of the forming surface, whereby a reduced basis weight of fibrous material is deposited on such portion of the forming surface.

Claim 10

Dependent Claim 64 words

A method according to claim 8, further comprising dividing the first arcuate segment into transverse subsegments defining corresponding vacuum laydown subzones on the forming surface, restricting gas flow through at least one of the forming surface vacuum laydown subzones, for effecting a transversely varying differential pressure on the forming surface vacuum laydown zone, whereby the laid fibrous article has a transversely varying basis weight.

Claim 11

Dependent Claim 43 words

A method according to claim 9, wherein the first arcuate segment is divided into three transverse subsegments defining corresponding vacuum laydown subzones on the forming surface and wherein the gas flow rate is restricted through the transversely outer forming surface vacuum laydown subzones.

Claim 12

Dependent Claim 77 words

A method according to claim 1, further comprising diverting a portion of the air drawn through the vacuum laydown zone on the forming surface into the first arcuate segment, under positive pressure into a second arcuate segment defining a pressurized take-off zone for flow through the forming surface in a direction opposite to flow of gas through the forming surface in said vacuum laydown zone, to effect removal of the laid fibrous article from the forming surface.

Claim 13

Dependent Claim 36 words

A method according to claim 1, further comprising abradingly trimming an excess thickness of a laid fibrous web deposited on the forming surface to yield of a substantially uniform predetermined thickness of said laid fibrous web.

Claim 14

Independent Claim 265 words

An apparatus for forming a laid fibrous article, comprising: a foraminous forming surface for depositing fibers under the influence of a pressure differential imposed on the forming surface; a rotatable cylindrical drum, an outer circumferentially extending cylindrical wall surface of which is comprised of said forming surface; an inner ring which is capable of passing air therethrough and which is connected to rotate with said forming surface and define an annular space therebetween; a plurality of circumferentially spaced, transverse sealing members connected in said annular space in sealing engagement between said inner ring and said forming surface; a plurality of radially extending, stationary baffles sealingly disposed in the interior of said rotatable cylindrical drum to divide the interior into plural arcuate segments, said segments defining and communicating with respective differential pressure zones on the forming surface, and said differential pressure zones including a vacuum laydown zone located on a portion of said forming surface over a first of said interior arcuate segments; a sealing flange member connected to a selected stationary baffle and arranged to contact said inner ring with a slideable, sealing engagement, said sealing flange member extending axially across a width dimension of said stationary baffle and extending circumferentially with a length which is at least equal to a circumferential distance between consecutive transverse sealing members; and pneumatic flow means comprising vacuum suction means joined in gas flow communication with said first arcuate segment in said rotatable cylindrical drum for drawing air through the vacuum laydown zone on the forming surface into the first arcuate segment and out of the rotatable cylindrical drum.

Claim 15

Independent Claim 265 words

An apparatus for forming a laid fibrous article, comprising: a foraminous forming surface for depositing fibers under the influence of a pressure differential imposed on the forming surface; a rotatable cylindrical drum, an outer circumferentially extending cylindrical wall surface of which is comprised of said forming surface; an inner ring which is capable of passing air therethrough and which is connected to rotate with said forming surface and define an annular space therebetween; a plurality of circumferentially spaced, transverse sealing members connected in said annular space in sealing engagement between said inner ring and said forming surface; a plurality of radially extending, stationary baffles sealingly disposed in the interior of said rotatable cylindrical drum to divide the interior into plural arcuate segments, said segments defining and communicating with respective differential pressure zones on the forming surface, and said differential pressure zones including a vacuum laydown zone located on a portion of said forming surface over a first of said interior arcuate segments; a sealing flange member connected to a selected stationary baffle and arranged to contact said inner ring with a slideable, sealing engagement, said sealing flange member extending axially across a width dimension of said stationary baffle and extending circumferentially with a length which is at least equal to a circumferential distance between consecutive transverse sealing members; and pneumatic flow means comprising vacuum suction means joined in gas flow communication with said first arcuate segment in said rotatable cylindrical drum for drawing air through the vacuum laydown zone on the forming surface into the first arcuate segment and out of the rotatable cylindrical drum.

Claim 16

Dependent Claim 27 words

An apparatus as recited in claim 13, wherein said forming surface includes a plurality of concavely contoured forming surface portions circumferentially spaced apart on said forming surface.

Claim 17

Dependent Claim 63 words

An apparatus as recited in claim 14, wherein said concavely contoured surface portion of the forming surface is bounded by walls angularly oriented, with respect to the plane of the forming surface proximally adjacent the concavely contoured surface portion, to define an included angle therebetween of from about 45° to 68°, whereby the laid fibrous article is readily removable from the forming surface.

Claim 18

Dependent Claim 63 words

An apparatus as recited in claim 14, further comprising a pair of axially spaced, circumferential sealing members, said circumferential sealing members located in said annular space adjacent to longitudinal side wall members of said concavely contoured forming surface portions and connected in sealing engagement with said transverse sealing members, and said circumferential sealing members operable to reduce cross flow through said annular space.

Claim 19

Dependent Claim 18 words

Apparatus according to claim 14, wherein the concavely contoured surface portion is of a generally inverted frusto-pyramidal shape.

Claim 20

Dependent Claim 37 words

Apparatus according to claim 17, wherein the concavely contoured surface portion is elongate in shape, and its bounding walls comprise longitudinal side walls and transverse end walls joined at their bottom edges to a base wall member.

Claim 21

Dependent Claim 35 words

Apparatus according to claim 18 wherein the included angles of the longitudinal side walls are between about 55° and 68°, and the included angles of the transverse end walls are between about 45° and 60°.

Claim 22

Dependent Claim 67 words

Apparatus according to claim 13, further comprising a vacuum attenuating plate positioned in closely spaced registration with, and transverse to flow of gas through, the forming surface, for diminution of the pressure differential exerted on the forming surface in register with the vacuum attenuating plate, whereby a reduced basis weight of fibrous material may be deposited on the forming surface in register with said vacuum attenuating plate.

Claim 23

Dependent Claim 27 words

Apparatus according to claim 20, wherein the vacuum attenuating plate is generally U-shaped, with its inner edge circumjacent to bounding walls of the concavely contoured surface portion.

Claim 24

Dependent Claim 78 words

Apparatus according to claim 13, further comprising means for diverting a portion of the air drawn through the vacuum laydown zone on the forming surface into the first arcuate segment, under positive pressure into a second arcuate segment defining a pressurized take-off zone for flow through the forming surface in a direction opposite to flow of gas through the forming surface in said vacuum laydown zone, to effect removal of the laid fibrous article from the forming surface.

Claim 25

Dependent Claim 93 words

Apparatus according to claim 13, further comprising: arcuate walls, located in the first arcuate segment of the rotatable cylindrical drum in transverse, axially spaced relationship to one another, for dividing the first arcuate segment into transverse subsegments defining corresponding transverse vacuum laydown subzones on the forming surface; and flow restriction means interposed between at least one of the forming surface vacuum laydown subzones and the vacuum suction means, for effecting a transversely varying differential pressure on the forming surface vacuum laydown zone, whereby the laid fibrous article has a transversely varying basis weight.

Claim 26

Dependent Claim 62 words

Apparatus according to claim 23, wherein two arcuate walls are disposed in the first arcuate segment of the rotatable cylindrical drum to divide the first arcuate segment into three transverse subsegments defining corresponding vacuum laydown subzones on the forming surface, and wherein the flow restriction means are interposed between the transversely outer forming surface vacuum laydown subzones and the vacuum suction means.

Claim 27

Dependent Claim 23 words

Apparatus according to claim 13, further comprising means for trimming an excess thickness of a laid fibrous web deposited on the forming surface.

Claim 28

Dependent Claim 47 words

Apparatus according to claim 25, wherein the trimming means comprise a roller disposed in adjacent spaced relationship to the forming surface, and means for translating the trimming roller and forming surface in opposite directions relative to one another, to abradingly remove excess thickness of the fibrous web.

Claim 29

Dependent Claim 28 words

An apparatus as recited in claim 13, wherein said sealing flange member is arranged to extend circumferentially away from a housing which channels fibers to said forming surface.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1990-05-18	1990-11-17	1991-05-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1994-05-18	1994-11-17	1995-05-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1998-05-18	1998-11-17	1999-05-19	$7700.00	Window Closed / Lapsed

Apparatus and process for forming a laid fibrous web

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag