US2958379A

US2958379A - Paper machine forming section

Info

Publication number: US2958379A
Application number: US612182A
Authority: US
Inventors: Hornbostel Lloyd
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1956-09-26
Filing date: 1956-09-26
Publication date: 1960-11-01
Anticipated expiration: 1977-11-01

Description

Nov. 1, 1960 1.. HORNBOSTEL PAPER MACHINE FORMING SECTION Filed Sept. 26, 1956 L h2g0 Hambos/e/ 121 75 2,958,379 Patented Nov. 1, 1960 Fire 2,958,379 PAPER MACHINE FORMING SECTION Lloyd Hornbostel, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Filed Sept. 26, 1956, Ser. No. 612,182

7 Claims. (Cl. 162-318) This invention relates to a paper forming machine, and more particularly, to an improved forming section for paper machines.

In one type of paper machine wherein the instant invention is particularly useful, the forming region of the machine comprises a looped forming wire with a rotatably mounted foraminous cylinder within the loop of the forming wire for effecting fibrous web formation on the wire. An inlet feeds stock onto the wire usually along the region of the upper quadrant of the uprunning side of the cylinder. This arrangement is used in cylinder type paper machines wherein a short looped forming Wire is trained over the cylinder mold; and this arrangement may also be used in a Fourdrinier type paper machine wherein the Fourdrinier wire is trained around an open breast roll. In either arrangement guide rolls within the loop of the wire are arranged so that the wire covers approximately the upper quadrant of the uprunning or oncoming side of the rotating cylinder. Sealing means are associated with the wire just before it comes in contact with the oncoming (or uprunning) side ofthe cylinder and just after the wire is taken away from the off-running side of the cylinder. Suction applying means cooperate with such sealing means to create a suction in the interior of the cylinder mold and its enclosure and a pressure differential across the upper quadrant on the uprunning side, so as to assist in drawing water from the stock through the forming wire and the open face of the cylinder. At higher operating speeds, however, it has been found that the paper machines of the type just described seem unable to effect satisfactory dewatering of the web. The instant invention is based in part on the discovery of the cause of such inadequate dewatering at high speeds and in part upon the discovery of a method and means for preventing the same. It has been discovered that the rotating foraminous cylinders at high operating speeds rotate so rapidly in the operation of the paper machine that centrifugal forces hold the water against the interior of the cylinder along the uprunning and top sides of the cylinder in spite of suction forces applied to the wire. In fact, a layer of Water is actually retained against the inside of the cylinder and the back side of the wire along the upper quadrant of the cylinder on the uprunning side thereof. Such layer of water tends to be thrown back against the wire (and even back into the web on the opposite side thereof) as the wire is taken away from the off-running side of the cylinder, and as it passes over the sealing means ordinarily cooperating with the bottom of the wire in this portion of the wire run.

In the instant invention sealing means associated with the bottom side of the wire at the off-running side of the cylinder in the manner hereinbefore employed are not used. Instead, a sealing member (cooperating with the suction applying means) is mounted in close running relation with the cylinder itself at the off-running side thereof and spaced from the bottom of the wire. Such sealing means are spaced from the bottom of the wire a predetermined distance to permit the entry of gas under pressure from a suitable source at higher pressure between such sealing means and the wire, and against the cylinder. This arrangement permits a rush of air back against the foraminous surface of the cylinder just after thewire is separated therefrom at the off-running side; and this rush of air drives water (against the centrifugal force) back through the foraminous cylinder surface and breaks up the layer of water tending to be retained on the inside surface of the cylinder. It also permits a pickup roll or suction pickup roll to take the Web up off a wire free from water on the bottom side.

It is, therefore, an important object of the instant invention to provide an improved paper machine particularly suited for high speed operation.

Other and further objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed disclosure thereof and the drawings attached hereto and made a part hereof.

Figure l is an elevational view of a cylinder type paper machine embodying the instant invention with parts shown in section and parts shown diagrammatically.

Referring now to Figure l, a cylinder type paper ma chine embodying the instant invention is indicated generally by the reference numeral 200 (wherein similar elements to those hereinbefore described have the same reference numerals in the 200 series) and this machine 200 comprises a looped forming wire 211, a cylinder mold 212 within the loop of the forming Wire 211 for effecting fibrous web formation on the wire 211 in the region 212a of approximately the upper quadrant of the uprunning side (indicated by an arrow) of the cylinder mold 212, and a guide roll 213 within the loop of the Wire 211 guiding a reach 211a thereof away from the cylinder mold 212 at the oif-running side of the cylinder mold 212 (actually near the top of the off-running side of the cylinder mold 212), and an inlet 214 feeding stock onto the oncoming side of the wire covered cylinder mold 212.

As will be seen, the wire 21'1 passes (in the direction indicated by the arrow heads) along the horizontal reach 211a from the off-running side of the cylinder mold 212 over a guide roll 213, then down around a lower guide roll 215 and back beneath a forward guide roll 216 which guides the Wire along an upwardly directed reach 21112 past vacuum sealing means indicated diagrammatically at 217 onto the upper quadrant 212a of the uprunning side of the cylinder mold 212. Stock flows through an inlet 214 onto the wire in the region of said upper quadrant 212a. In the region of the quadrant 212a, the wire and the cylinder mold surfaceare both foraminous cylindrical forming surfaces, which are superimposed. Both the foraminous wire surface and the foraminous surface of the open cylinder mold 212 permit Water to pass through freely, so that a fibrous Web W" may form in the region of the quadrant 212a.

A pickup felt F (which is actually a looped felt that'may pick up webs from a plurality of cylinder mold units such as the one here shown) is positioned above the cylinder mold 12 and the oif-running reach 211a of the forming wire 211 to receive the fibrous web W" from the wire 211. A suction roll 218 with a suction area 218a for web pickup and Web retention on the bottom of the felt F" urges the felt F downwardly against the wire 211- just after the wire 211 separates from the cylinder 212 to assist in web pickup by the felt F", As here shown, the suction roll 218 and the cylinder mold 212 are in nip-defining relationship at a nip N just after which the transfer of the Web W" from the wire 211 to the felt F" is accomplished; At this nip N the wire 211 separates from the off-running side of the cylinder mold 212.

As will be noted, the cylinder mold 212 is rotatably mounted on means (not shown) within a suction or vacuum box indicated generally by the reference numeral 219 which comprises a floor 219a, a forward wall 21% extending upwardy from the floor to the wire seal 217, and a rear wall 2190 which, in the prior art, extended upwardly to make wire seal contact with the bottom of the off-running wire reach 211a. Also, suitable means for evacuating the box 219, such as a pump 220 sh wn diagrammatically are provided, so that a pressure differential may be maintained across the wire 211 and the cylinder mold surface in the region of the quadrant 212a to assist in drawing water from the stock and into the interior of the cylinder mold 212.

In the instant invention. the rear wall 2190 of the suction box 219 extends upwardly but is spaced from the bottom of the wire reach 211a and is provided at its upper end with a sealing member 219d (which is in the present embodiment a continuation of the metal wal s of the box 219) that extends back toward the upper portion of the off-runnin s de of the cvh'nder mold 212 to close runn ng relation therewith. The member 219d thus functions as a se l ng member with the surface of the cylinder mold 212 in tead of the bottom of the wire 211. Airblast means 221 are in erposed between the wire reach 211a and the sealing member 2 9d for urging a as such as air under p essure back between the wire 211 and the sealing member 2 9d a ainst the surface of the c nder mo d 212. As he e shown. the airblast means 221 compr se a header 2211.1 and a nozzle member 22% which extends a sub tantial distance into the space between the wire 211 and the sealin member 219a' and is aimed so as to direct air at t e off-running side of the nip N". In this wav the a r-blast serves to drive water away at the critica point a d actually the air may be driven back through the su face of the cylinder mold 212 so as to comp etel disrupt the layer L of water tend ng to follow the inside surface of the cylinder mo d 212. in the manner shown in the drawing. In addition. the air-blast tends to assist the suction gland 218a of the suction roll 218 in ccomplishing transfer of the web W" from the wire 211 to t e felt F". As here shown diagrammatically a pump 2210 or other suitable means for producing as under pressure is connected to the header 221a. The air-blast is concentrated in such a re atively s all re ion of the overall surface of the cylinder mold 212 that the amount of air passing into the c nder at this point is relatively small so that vacuum within the cylinder mold is not lost.

It will be understood that mod fications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

I claim as my invention:

1. In a cylinder type paper machine. in combination, a looped forming wire. a c linder mold within the loop of said forming wire for effe t ng fibrous web formation on the wire, a guide ro l within the loop of said Wire guidin a reach thereof away from the cylinder mold at the off-running side thereof. a sealin member in close running relation to the off-running side of said cylinder mold and spaced from said wire. suction means cooperatin with said sealing member to create suction within the cylinder mold. and as-blast means interposed between the wire and sealing member urgin gas under pressure back between the wire and the sealing member against the c linder mold.

2. In a cylinder type paper machine, in combination, a looped forming wire, a cylinder mold within the loop of said forming wire for effecting fibrous web formation on the wire, an inlet feeding stock onto the oncoming side of the wire covered cylinder mold, a guide roll within the loop of said wire guiding a reach thereof away from the cylinder mold at the off-running side thereof, a sealing member in close running relation to the off-running side of said cylinder mold and spaced from said wire, suction means cooperating with said sealing member to create suction within the cylinder mold, and gas-blast means interposed between the wire and the sealing member urging gas under pressure back between the wire and the sealing member against the cylinder mold.

3. In a cylinder type paper machine, in combination, a looped forming wire, a cylinder mold within the loop of said forming wire for effecting fibrous web formation on the wire, a guide roll within the loop of said wire guiding a reach thereof away from the cylinder mold at the off-running side thereof, -a pickup felt having a felt run positioned above the reach of said forming wire to receive the fibrous web therefrom, a sealing member in close running relation to the off-running side of said cylinder mold and spaced from said wire, suction means cooperating with said sealing member to create suction within the cylinder mold, and gas-blast means interposed between the wire and the sealing member urging gas under pressure back between the wire and the sealing member against the cylinder mold.

4. In a cylinder type paper machine, in combination, a looped forming wire, a cylinder mold within the loop of said forming wire for effecting fibrous Web formation on the wire, a guide roll within the loop of said wire guiding a reach thereof away from the cylinder mold at the off-running side thereof, a pickup felt having a felt run positioned above the reach of said forming wire to receive the fibrous web therefrom, a suction roll urging said felt run against said wire reach to assist in web pickup by the felt, a sealing member beneath said suction roll in close running relation to the off-running side of said cylinder mold and spaced from said wire, suction means cooperating with said sealing member to create suction within the cylinder mold, and gas-blast means interposed between the wire and the sealing-member urging gas under pressure back between the wire and the sealing member against the cylinder mold.

5. In a cylinder type paper machine, in combination, a looped forming wire, a cylinder mold 'within the loop of said forming wire for effecting fibrous web formation on the wire, an inlet feeding stock onto the oncoming side of the wire covered cylinder mold, a guide roll within the loop of said wire guiding a reach thereof away from the cylinder mold at the off-running side thereof, a pickup felt having a felt run positioned above the reach of said forming wire to receive the fibrous web therefrom, a sealing member in close running relation to the off-running side of said cylinder mold and spaced from said wire, suction means cooperating with said sealing member to create suction within the cylinder mold, and gas-blast means interposed between the Wire and the sealing member urging gas under pressure back between the wire and the sealing member against the cylinder mold.

6. In a cylinder type paper machine, in combination, a looped forming Wire, a cylinder mold within the loop of said forming wire for effecting fibrous web formation on the wire, an inlet feeding stock onto the oncoming side of the wire covered cylinder mold, a guide roll within the loop of said wire guiding a reach thereof away from the cylinder mold at the off-running side thereof, a pickup felt having a felt run positioned above the reach of said forming wire to receive the fibrous web therefrom, a suction roll urging said felt run against said wire reach to assist in web pickup by the felt, a sealing member beneath said suction roll in close running relation to the off-running side of said cylinder mold and spaced from said wire, suction means cooperating with said sealing member to create suction within the cylinder mold, and gas-blast means interposed between the wire and the sealing member urging gas under pressure back between the wire and the sealing member against the cylinder mold. p

7. In a paper machine, in combination, a looped forming wire, a rotatably mounted foraminous cylinder within the loop of said forming wire for effecting fibrous 2,958,379 5 web formation on the wire, guide means within the loop References Cited in the file of this patent of said wire guiding a reach thereof away from said cylinder at the off-running side thereof, a sealing mem- UNITED STATES PATENTS her in close running relation to the off-running side of ,262,698 Pope Apr. 16, 1918 said cylinder and spaced from said wire, suction means 5 ,534,620 Wagner Apr. 21, 1925 cooperating with said sealing member to create suction 1,581,656 Monaghan Apr. 20, 1926 within said cylinder, and gas-blast means interposed be- 2, 54,719 Berry Apr. 18, 1939 tween the wire and the sealing member urging gas under 2,162,097 Metcalf June 13, 1939 pressure back between the wire and the sealing member 2,535,732 Goodwillie Dec. 26, 1950 against said cylinder. 1 2,755,710 Beachler July 24, 1956