US3440136A

US3440136A - Papermaking apparatus including two wire sheet formers having means for air purging

Info

Publication number: US3440136A
Application number: US514185A
Authority: US
Inventors: Herbert C Nelson; David W Appel
Original assignee: Kimberly Clark Corp
Current assignee: Kimberly Clark Corp
Priority date: 1965-12-16
Filing date: 1965-12-16
Publication date: 1969-04-22
Anticipated expiration: 1986-04-22

Description

April 1969 H. c. NELSON ETAL 3,440,136

PAPERMAKING APPARATUS INCLUDING TWO WIRE SHEET FORMERS HAVING MEANS FOR AIR PURGING Sheet 1 Filed Dec. 16, 1965 3,440,136 ORMERS ET F Sheet H. C. NELSON ETAL FARATUS INCLUDING TWO WIRE SHE HAVING MEANS FOR AIR PURGING PAPERMAKING AP April 22, 1969 Filed Dec. 16, 1965 PIIJM A J 3 l L 6 2 p i p 1 w z p 4 H H 1 6 HI 3 .A

April 1969 H. c. NELSON ETAL 3,440,136

APERMAKING APPARATUS INCLUDING TWO WIRE SHEET FORMERS HAVING MEANS FOR AIR PURGING 3 Sheet of 4 Filed Dec. 16, 1965 .c. NELSON ETAL 3,440,136 PAPERMAKING APPARATUS INCLUDING TWO WIRE EET FORMERS HAVING MEANS FOR AIR PURGIN 16, 1965 April 22, 1969 Sheet Filed Dec.

Hod.

United States Patent 3,440,136 PAPERMAKING APPARATUS INCLUDING TWO WIRE SHEET FORMERS HAVING MEANS FOR AIR PURGING Herbert C. Nelson, New Milford, Conn., and David W.

Appel, Neenali, Wis., assignors to Kimberly-Clark Corporation, Neenall, Wis., a corporation of Delaware Filed Dec. 16, 1965, Ser. No. 514,185 Int. Cl. D2112 1/32, /00

US. Cl. 162275 7 Claims ABSTRACT OF THE DISCLOSURE The invention relates to papermaking machines and more particularly to such machines of the type comp-rising a pair of Fourdrinier screens or wires brought together and having paper stock discharged between them so as to form a paper sheet or web between them.

Machines of this general nature have been heretofore proposed; however, the resulting web has been defective by being marked by air bubbles, due to the fact that air is drawn between the wires, along with the stock discharged between the wires, as the wires travel together.

It is, therefore, an object of the present invention to provide an improved papermaking machine of this general type provided with means for purging air from the wires as they travel together, so that stock undiluted by air bubbles is disposed between the wires for thereby forming a web unmarked by such bubbles.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and claimed for carrying out the above stated objects, and such other objects, as will be apparent from the following description of preferred forms of the invention, illustrated with reference to the accompanying drawings, wherein:

FIG. 1 is a diagrammatic side elevational view of a papermaking machine embodying the principles of the invention and including a pair of foraminous paper forming wires passing by the two opposite sides of a vertically disposed stock inlet and over a pair of opposite, adjacent, stationary nose pieces for holding the wires in close proximity to each other, the wires being sealed with respect to the sides of the inlet by opposite sealing devices on the inlet;

FIG. 2 is a longitudinal sectional view of the inlet together with adjacent parts;

FIG. 3 is a view on an enlarged scale of one of the forming wires of the machine, at the edge of the forming wire, and taken from a line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken on line 4-4 of FIG. 3;

FIG. 5 is a sectional view taken on the same plane 3,440,136 Patented Apr. 22, 1969 through the machine as FIG. 2 and showing a modified type of sealing device for the inlet;

FIG. 6 is a view similar to FIG. 2 of a modified form of the machine including rolls for mounting the two wires of the machine which are used in lieu of the stationary nose pieces; and

FIG. 7 is a side elevational view of a modified form of the machine in which the inlet is horizontally disposed instead of being vertically disposed.

Like characters of reference designate like parts in the several views.

Referring now to the drawings and in particular to FIGS. 1 and 2, the papermaking machine illustrated therein may be seen to comprise a pair of endless forming screens or

wires

10 and 11. The wires extend in close proximity to the

lower sides

12 and 13 of a paper stock; inlet 14; and, as will be observed from FIG. 2 in particular, the

sides

12 and 13 approach each other toward the lower end of the inlet 14, and the

wires

10 and 11 approach each other also in the same manner, which is at approximately an angle of The

wires

10 and 11 pass around

nose pieces

15 and 16 fixed with respect to a frame 17 by means of inwardly extending

frame portions

17a and 17b, and the wires extend downwardly from the nose pieces and approach each other more closely below the nose pieces, as may be seen in FIG. 2. The wire 11 is also supported by means of a suction couch roll 18 and turning rolls 19, 2'0, 21 and 22; and the wire 10 is also supported by means of turning

rolls

23, 24, 25 and 26. Appropriate ones of the rolls 19 to 26 may be utilized as stretch and guide rolls for the

respective wires

10 and 11.

A pickup roll 27 has a nip with an unsupported portion of the wire 11 between the

rolls

18 and 19, and an endless felt 28 passes over the roll 27 and between this roll and the wire 11. The felt 28 is supported by means of a plurality of additional rolls (not shown). and the felt is also arranged with a conventional drier portion (not shown) of the papermaking machine so that a paper web on the felt 28 transfers to and is dried by the drier portion of the machine. The

rolls

18 and 27 have perforate exterior shells, and

suction glands

29 and 30 connected to appropriate suction sources are provided in the

rolls

18 and 27.

The inlet 14 comprises a housing 31 on which the

sides

12 and 13 are provided. A paper stock inlet conduit 32 if fixed with respect to the housing 31 at the upper end of the housing and comprises a relatively large diameter inlet 33 and a relatively small diameter outlet 34. A perforate diffuser element 35 is disposed in the housing 31 and has a plurality of openings 36 extending therethrough which are in spaced rows and which are connected to the interior of the conduit 32. A contraction section 37 provides a paper stock passage 38 which is relatively thick at its inlet end and is quite thin at its outlet end and which has its inlet end in communication with the openings 36.

The relatively thin outlet end of the passage 38 is connected to a relatively long, thin stock discharge passage 39. The passage 39 is provided by means of opposite parallel plates 40 and 41 and opposite parallel plates 42 and 43. The plates 42 and 43 extend downwardly between the

nose pieces

15 and 16 so that their extreme lower ends come in close proximity to the

wires

10 and 11 as they pass around the

nose pieces

15 and 16. Adjustment spindles 44 and 45 extend through the housing 31 and are effective on the extreme lower ends of the plates 42 and 43 for the purpose of adjustably moving the plates 42 and 43 together so that the passage 39 may be substantially unitorm in width particularly at its lower end.

The frame 17 is so constructed as to provide

water chambers

46 and 47 the lower ends of which are defined by the

frame portions

17a and 17b and which are adjacent to the portions of the wires and 11 that pass across the

sides

12 and 13 of the inlet. The

chambers

46 and 47 are respectively provided with

water inlets

48 and 49, and

water outlet slots

50 and 51 connected to a suitable sump are provided in the

sides

12 and 13 opposite the

chambers

46 and 47.

Foils

52 and 53 are respectively provided in the

chambers

46 and 47 opposite the

slots

50 and 51; and, as will be noted, these foils have reduced thickness ends that extend downwardly and toward the

adjacent wires

10 and 11.

The frame 17 is constructed so as to provide water receiver chambers 54 and '55 located above the

chambers

46 and 47, and each of the

chambers

54 and 55 has an outlet opening 56 consisting of an overflow in its side. The inlet 14 is provided with means for jetting white water along and adjacent the

wires

10 and 11 at the opposite edges of the wires comprising a pair of white water conduits 57 connected to nozzles 58 (see FIGS. 3 and 4).

The frame 17 is constructed to provide forming

boxes

59 and 60 located below the

chambers

46 and 47. Foils 61 and 62 are provided in the forming

boxes

59 and 60, and these foils extend generally downwardly and sidewardly with respect to the

wires

10 and 11, as is apparent from FIG. =2. Sealing members 63 and 6'4 are provided at the lower sides of the forming

boxes

59 and 60, and these extend generally in the same direction as the foils 61 and '62. The

boxes

59 and 60 are connected by any suitable conduit (not shown) with a white water sump.

A suction box 65 is located beneath the forming box 59, and the box 65 may be connected to any suitable source of suction by a suitable conduit (not shown). Foils 66 extending generally in the same direction as the foils 61 are provided in the box 65 adjacent the wire 11.

In operation, the

wires

10 and 11 are driven about their supporting rolls 18 to 26 so that the wires move downwardly along the

sides

12 and 13 of the inlet 14. Paper stock is discharged into the conduit 32 and flows through the conduit. Preferably, sufficient paper stock is provided to the conduit 32 so that a part of it flows out of the small diameter outlet 34 and is recirculated back to the relatively large diameter inlet '33. Most of the stock within the conduit 32 flows through the openings 36 of the diffuser element 35; and, since the openings 36 extend generally at right angles to the flow of stock through the conduit 32, the openings 36 have the function of changing the direction of stock flow through substantially this angle.

The stock flows through the openings 36 into the stock passage 38, and the passage 38 narrows the stock stream to the thickness of the passage 38 at its lower or outlet end. The stock then flows through the passage 39 having the same relatively small thickness of the outlet end of the passage 38, and the stock is discharged from the lower end of the passage 39 between the nose pieces and 16 and the portions of the

wires

10 and 11 supported by the nose pieces. The stock in passing between the parallel, closely spaced plates 40 to 43 is thereby given fine scale turbulence so that, as it emerges from the lower ends of the plates 42 and 43, it is very homogeneous. An inlet of the same general type as the inlet 14 is disclosed and claimed in the application of James Loynd, Serial No. 437,540, filed March 5, 1965, and now Patent No. 3,360,428 and further details of its construction and operation may be obtained from this patent.

The two

wires

10 and 11 move downwardly around the nose pieces '15 and 16, past the foils 61 and 62 and between the sealing

members

63 and 64. The forming

boxes

59 and 60 are drained to a suitable sump so as to keep them substantially empty of liquid and preferably have a vacuum applied to them. Water drains from the stock between the

wires

10 and 11 as they pass downwardly from the

nose nieces

15 and 16, and the foils 61 and 62 are in contact with the

wires

10 and 11 and strip water from the surfaces of the

wires

10 and 11 so as to draw off the water from the wires and from the stock therebetween which is being formed into a web particularly in these portions of the

wires

10 and 11. It will be noted that the wires '10 and 11 approach each other closer as they move away from the

nose pieces

15 and 16 and toward the sealing

members

63 and 64, and the stock is therefore somewhat compressed as water is drained from it in order to form the web.

The wire 10 separates from the wire 11 beneath the sealing

members

63 and 64 due to the placement of the roll 23 with respect to the roll 18; and the paper sheet or web illustrated as web A, is kept on the surface of the wire 11 by the suction box 65 located below the seal 64 and within the wire '11. The web A remains on the wire 11 as it passes around the suction couch roll 18, and the gland 29 within the perforate shell of the roll 18 functions not only to dewater the web A to some extent but also functions to maintain the web A on the surface of the wire 11 as it passes around the roll 18. The web A transfers onto the felt 28 as the web passes into contact with the felt on the surface of the roll 27, and the suction gland 30 within the perforate shell of the roll 27 assists in causing the web A to transfer onto the felt 28. After such transferrence to the felt 28, the web is further dewatered by conventional presses (not shown) and is then dried by transferring it onto a suitable heated drier drum or drums (not shown) in accordance with conventional practice.

Either fresh water or clarified white water (the water drained from the web A as it passes through the forming boxes 59 and 60) is supplied to the inlets 48 and "49 for the

chambers

46 and 47. The water flows through the

chambers

46 and 47, through the

wires

10 and 11, and into the

slots

50 and 51 in the inlet sides 12 and 13, from which it flows to a suitable sump. The water in passing through the

wires

10 and 11 int-o the

slots

50 and 51 acts to purge and carry away with it any air within the interstices of the

wires

10 and 11. Sufficient water is supplied to the

inlets

48 and 49 so that it also flows upwardly into the

chambers

54 and 55, and the water level within the latter chambers is maintained substantially constant by means of the outlet openings 56 for the chambers. Due to the maintenance of the water level in the

chambers

54 and 55, the

wires

10 and 11 in their downward travel first pass through the water in these chambers, which tends to release air from within the interstices of the wire, prior to passage of the wires over the

slots

50 and 51, which complete the purging of the air from the wires, so that the interstices of the wires, as they pass between the

nose pieces

15 and 16, are substantially filled with water. Thus, substantially pure stock exists between the

wires

10 and 11 as they pass between the

nose pieces

15 and 16; and a substantially uniform web A, which is unmarked by air bubbles, is obtained.

The sides of the inlet 14 are substantially sealed with respect to atmosphere by means of the nozzles 58 (see FIGS. 3 and 4) located in the sides of the inlet. White water is supplied to the conduits 57, which is discharged through the nozzles 58 onto marginal edge portions of the

wires

10 and 11, so as to define the edges of the web A.

The inlet and wire arrangement illustrated in FIG. 6 is basically the same as that of FIG. '2 except that the

nose pieces

15 and 16 have been replaced by means of rolls and 76. These rolls are respectively enclosed in

roll enclosures

77 and 78 which are fixed with respect to the frame 17 and take the place of the

frame portions

17a and 17b. The

roll enclosures

77 and 78 respectively are provided with internal

cylindrical surfaces

79 and 80 which substantially embrace the

rolls

75 and 76 except for the portion of the rolls about which the wires and 11 travel and have contact.

Although the

rolls

75 and 76 may be solid rolls, they are preferably of the so -called Mount Hope type, such as shown in FIG. 1 of the patent to J. D. Robertson et al., 3,099,072, issued July 30, 1963, which is of such construction that the roll, even though being relatively long, may be adjusted so that it has substantially no longitudinal curvature. Briefly, each of these rolls comprises an outer sleeve 81 supported by inner spools 82. The roll comprises an inner tubular support 83, and bearings 84 of the ball type are disposed between the spools 82 and the tubular support 83. Caps or end plates 85 are provided on the ends of the tubular support 83, and a tension rod 86 extends through the tubular support 83 and through the caps 85. The rod 86 is in substantial contact with a part of the inner surface of the tubular support 83 that is located opposite to the portion of the sleeve 81 having the

respective wire

10 or 11 in contact with it and slightly downwardly with respect to a diameter passing through the center of the arc of the wire in contact with the surface of the roll so that the rod 86 can take the force due to the tension on the wire as well as the force tending to how the roll due to the weight of the roll itself. Nuts 87 are screwed onto the ends of the rod 86, and these nuts are tightened sufficiently so that sufficient tension is put on the rod 86 to hold the roll so that it is substantially straight and has no substantial longitudinal curvature. Utilizing such adjustable rolls allows the rolls to be made of relatively small diameter, such as 6 to 8 inches, while yet being longitudinally straight even though they have substantial length, corresponding with the width of the paper being made, such as between 160 to 240 inches.

The forming section illustrated in FIG. 6 operates substantially like that shown in FIG. 2, except that the

wires

10 and 11 move around the rotatable rolls 75 and 76 instead of the

stationary nose pieces

15 and 16. The

wires

10 and 11 pass around the

rolls

75 and 76 as the wires come together, and the

rolls

75 and 76 may be of the preferred small diameter to provide relatively short arcs at the lower tips of the plates 42 and 43, since the rolls are of the Mount Hope type. These rolls may be maintained substantially straight longitudinally, even though the rolls are of small diameter considering their length, by adjusting the nuts 87 in accordance with the teachings in the above-mentioned Robertson et al. Patent 3,099,072.

In connection with the embodiments before described, the chambers54 and 55 which act to seal with respect to atmosphere may be replaced by the seals 88 (see FIG. 5). The seals 88 are carried by the frame 17 and basically comprise a plurality of ribs 89 extending crosswise of the associated wire. Slots 90 connected to any suitable sump are provided in the inlet opposite the seals 88 for collecting and disposing of air and water from the vicinity of the associated wire and seal 88.

The forming sections shown particularly in FIGS. 2 and 6 and above described may be used vertically as shown in these figures or can also be used in any'other position, as desired. The forming sections may be used horizontally, for example, as illustrated in FIG. 7. Referring to FIG. 7, the horizontal machine includes the wires 10a and 11a corresponding with the

wires

10 and 11, and these wires travel around the inlet 14, between the nose pieces 15 and 16 (or rolls 75 and 76) and the

form ing boxes

59 and 60 and also across the suction box 65, all as above described in connection with the vertical embodiments of the machine. The wire 10a exterior of the forming section is supported by means of rolls 95,

96, 97 and 98. The wire 11a exterior of the forming section is supported by means of

rolls

99, 100, 101, 102, 103, 104 and 105. The rolls to 104 are simple turning rolls, and the roll 105 is a couch roll having a perforate exterior shell with a vacuum gland 106 therein.

An endless felt 107 is held in contact with a stretch of the wire 11a between the

rolls

104 and 105 by means of a pickup roll 108. The roll 108 has a perforate exterior shell with a suction gland 109 therein. The felt 107, in accordance with conventional practice, may pass through a plurality of presses; and one such press 110 is illustrated which comprises press rolls 111 and 112 having a pressure nip between them and with the felt passing through the nip.

It is apparent that when the forming sections illustrated in FIGS. 2 and 6 are used in any other than vertical positions (with the conduit 32 positioned at the top and the passage 39 located therebelow), the

chambers

54 and 55 cannot hold water. Therefore, for forms of the invention in which the inlet 14 discharges paper stock other than downwardly, the

chambers

54 and 55 are dispensed with and the seals 88 (see FIG. 5) are substituted.

In operation, the forming section of the FIG. 7 embodiment functions in the same manner as do the vertically disposed forming sections shown in FIGS. 2 and 6, and the web B remains on the wire 11a due to the action of the suction box 65 effective on the wire 11a. The web B travels over the suction roll 105 and is kept on the associated wire similarly to the action on the web A in traveling over the roll 18. The web B then passes into contact with the felt 107 and is drawn onto the surface of the felt in part due to the action of the suction pickup roll 108. The web B is then dewatered by pressing and is dried in accordance with conventional practice.

It will be apparent that in all of the above described embodiments, the forming area, which is that area between the opposite wires in between and immediately below the

nose pieces

15 and 16 or the

rolls

75 and 76, is completely submerged in water. In this connection, it will be noted that the

stationary nose pieces

15 and 16 fixed with respect to the stationary frame 17 or the

rolls

75 and 76 rotatably disposed with respect to the stationary frame 17 and having a substantial nip between them constitute closely spaced guide members for the

wires

10 and 11. The

wires

10 and 11 approach the guide members at an included angle of about 90 in the illustrated embodiments due to the fact that the

rolls

22 and 26 and the rolls 95 and 99 from which the wires travel to the guide members are substantially spaced with respect to each other and due to the fact that the inlet sides 12 and 13 also have this included angle. The

wires

10 and 11 are acted on by the foils 61 and 62 and also by the sealing

members

63 and 64 which are more closely spaced depending on their distance from the

nose pieces

15 and 16 or rolls 75 and 76 so that the

wires

10 and 11 more closely approach each other as they travel toward the sealing

members

63 and 64 and thus provide a forming area that has a tapering crosssection. The

wires

10 and 11 are of foraminous screen material so that the white water from the web being formed between the wires may freely drain into the forming

boxes

59 and 60. The fact that the forming area, being that area between the

opposite wires

10 and 11 in between and immediately below the

nose pieces

15 and 16 or the

rolls

75 and 76, is completely submerged in water permits the use of the narrow turbulent flow nozzle made up of the parallel plates 40 to 43 substantially all the way up to the forming area. In addition, this construction allows the delivering of a highly turbulent stock smoothly to the forming area without impinging the jet of stock onto the opposite wires in an attempt to eliminate air.

The forming sections of the above described machines are advantageously constituted of totally enclosed, pressurized, twin wire forming devices having a manifold flow spreader (comprising the sections 35 and 37), the turbulent flow inlet (formed by the closely spaced, parallel plates 40 to 43) and a totally enclosed, precisely shaped, flooded, hydraulically sealed and pressurized forming area. Due to the fact that the

wires

10 and 11 are confined between the foils 61 and 62 below the nose pieces and 16 and the

rolls

75 and 76, formation problems generally associated with free surface instability are not encountered. In view of the fact that two opposite wires are utilized, preferably in a vertical disposition, symmetrical drainage resulting in a symmetrical product can be expected. Relatively low or no suction may be utilized with respect to the forming

boxes

59 and 60; and, particularly under these conditions, relatively low forming pressures are exerted over relatively large proportions of the drainage area involved, resulting in reduced wire mark, smoother surfaces on the base sheet, greater fines retention and a relatively short forming length. The use of the turbulent flow nozzle comprising the closely spaced, parallel plates 40 to 43 produces a homogeneous dispersal of the fibres in the stock; and, due to the fact that the ends of the plates 42 and 43 are located closely within the

nose pieces

15 and 16 or between the

rolls

75 and 76, a resulting quick set process for forming a sheet from this well dispersed fibrous suspension is attained, yielding improved formation and basis weight uniformity. The passage of the wires along the

sides

12 and 13 of the inlet immediately preceding the forming region located within and just below the

nose pieces

15 and 16 or rolls 75 and 76 yields improved formation through rectification of zones of high shear which otherwise would occur in flows along these walls. The above described machines also have the advantage of providing a relatively square sheet (a web in which the strength is about the same both lengthwise and crosswise), particularly of relatively heavyweight webs, such as newsprint or book paper base sheets. Such sheets, for example, may be in the 25 to 32 pounds per 3,000 square feet category, and they may be formed at speeds in excess of 3,000 feet per minute, for example, by the above described machines.

The

rolls

75 and 76 utilized in the FIG. 6 forming section in lieu of the fixed

nose pieces

15 and 16 advantageously reduce the wear on the

wires

10 and 11 not only by the nose pieces but also by the foils 61 and 62 in the forming

boxes

59 and 60. Assuming that the nip between the

rolls

75 and 76 is quite thin, the use of these rolls can be expected to advantageously reduce the amount of water accompanying the

wires

10 and 11 and flowing from the

chambers

46 and 47 into the forming

boxes

59 and 60.

As has been above explained, the forming sections illustrated in FIGS. 2 and 6 are preferably used vertically with the stock jetted downwardly between the plates 40 to 43; however, as has been illustrated, particularly in FIG. 7, the forming sections may be used horizontally as well. In addition, it will be apparent that, if desired, the forming sections of FIGS. 2 and 6 could be used with the conduit 32 located at the bottom and the stock being jetted upwardly into a nip between opposing forming wires. Although the opposing

wires

10 and 11 and opposing wires 10a and 11a have been illustrated, it will be apparent that, if desired, one of each pair of wires, such as the wires 11 and 11a, may be replaced by an endless fabric of another type, such as, for example, a felt. In this case, of course, substantially all of the drainage would be through the wire of the pair rather than the felt. Depending on the degree of vacuum applied to the forming

boxes

59 and 60, the device may be made relatively small in size, such as, for example, to have a total length of the order of 15 feet from the conduit 32 to the sealing

members

63 and 64.

It is to be understood that the invention is not to be limited to the specific constructions and arrangements shown and described, except only insofar as the claims may be so limited, as it will be apparent to those skilled in the art that, in addition to the changes mentioned in the preceding paragraph, other changes may be made without departing from the principles of the invention.

What is claimed is:

1. In apparatus for making a fibrous sheet from a slurry of fibrous stock, a pair of endless forming webs at least one of which is foraminous screen material, means for movably holding said webs in looped form and including a pair of web guide members supporting the webs and providing opposite stretches of the webs that extend along and are disposed adjacent to each other to define therebetween a sheet forming area and said means also including a pair of spaced apart rolls each associated with one forming web and from which the forming web travel to the said web guide members, means for directing stock between said webs and supporting guide members into said forming area, a housing for each of said webs and its respective guide member enclosing the said forming area to provide for immersing the forming area in liquid, each said housing extending toward a said roll to provide for immersion forming webs travel to the said web guide members, area, means providing a liquid inlet into each of said housings, means providing a liquid and air outlet in each of said housings located on the side of the forming web in the housing opposite to the liquid inlet into the housing so that liquid may flow from the housing inlet through the respective web and into the outlet to dislodge air traveling with the web and to carry the air into said outlet, and other means through which said forming webs travel as they leave said guide members and forming area, said other means including means to draw off liquid from said forming webs and stock.

2. In apparatus for making a fibrous sheet from a slurry of fibrous stock as set forth in claim 1, each of said forming webs being made of foraminous screen material, the said other means through which the forming webs travel as they leave the guide members and forming area being a pair of forming boxes to which vacuum pressure may be applied to draw off liquid from said forming webs and stock.

3. In apparatus for making a fibrous sheet from a slurry of fibrous stock as set forth in claim 1, each of said forming webs being made of foraminous screen material and said housing including stationary frame portions, said guide members being a pair of stationary nose pieces each carried by a said frame portion.

4. In apparatus for making a fibrous sheet from a slurry of fibrous stock as set forth in claim 1, each of said forming webs being made of foraminous screen material and said housing including stationary frame portions, said guide members constituting rotatable rolls having a nip between them into which the slurry of fibrous stock is directed and each said roll being supported by a said frame portion.

5. In apparatus for making a fibrous sheet from a slurry of fibrous stock as set forth in claim 1, each of said forming webs being made of foramious screen material, said means for directing stock between said guide members including a stock inlet, said inlet having a pair of surfaces extending at angles to each other and across which said forming webs extend and pass in traveling to said guide members, and said liquid and air outlets for said housings being provided in said surfaces of the stock inlet.

6. In apparatus for making a fibrous sheet from a slurry of fibrous stock as set forth in claim 5, said inlet comprising oppositely disposed spaced, parallel plates providing a narrow stock passage between them and said plates extending between said guide members and webs for directing the slurry of fibrous stock between the guide members and webs.

9 l0 7. In appartus for making a nbrous sheet from 9. 3,149,028 9/1964 Robinson 162303 slurry of fibrous stock as set forth in claim 5, and means 3,215,593 11/1965 Green 162301 constituting an overflow providing an additional liquid 3,215,594 11/1965 Baxter et a1 162303 outlet for each of said housings and located adjacent to the forming web in the housing and more remote from FOREIGN PATENTS the respective said guide member than said liquid and 5 air outlet provided in the respective said inlet surface. 888O43 8/1953 Germany DONALL H. SYLVESTER, Primary Examiner.

. ON, A 't t UNITED STATES PA S 10 A C HODGS SSlS an Examiner 3,293,121 12/1966 Martin 162358 2,255,951 9/1941 Tomtlund 162--275 34 242; 162203, 275

References Cited