A PRESS APPARATUS

Abstract: A press apparatus (10) is disclosed for pressing water from the formed web (W). The apparatus includes a press frame and a center roll (12) rotatably supported by the frame. An upstream roll (14) cooperates with the center roll (12) for defining therebetween a roll nip (N1) for the passage therethrough of the web. The arrangement is such that a first portion of water is removed from the web when the web extends through the roll nip (N1). A first extended nip press shoe (16) is disposed downstream relative to the roll nip. The first shoe (16) defines a first concave surface which cooperates with the center roll (12) for defining therebetween a first extended nip (N2) for the passage therethrough of the pressed web. The arrangement is such that a second portion of water is removed from the web when the pressed web extends through the first extended nip (N2). A second extended nip press shoe (20) is disposed downstream relative to the first shoe (16). The second shoe (20) defines a second concave surface which cooperates with the center roll (12) for defining therebetween a second extended nip (N3) for the passage therethrough of the pressed web. The arrangement is such that a third portion of water is removed from the web when the pressed web extends through the second extended nip (N3).

Description: TITLE: A PRESS APPARATUS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a press apparatus for pressing water from a formed web. More specifically, the present invention relates to an extended nip press apparatus for pressing water from a formed web. INFORMATION DISCLOSURE STATEMENT A formed web typically has between 50 to 90 percent water therein. Consequently, a large proportion of such water is removed from the web by pressing the web. Typically, a formed web is guided between a pair of counter rotating rolls which define therebetween a press nip. The press nip presses water from the web so that the web can be guided towards a drying section in which the web extends around a plurality of heated drying cylinders which remove most of the remaining water therefrom. More recently, extended nip press arrangements have been commercialized for removing greater quantities of water from the web prior to guiding the web around the heated drying cylinders. Extended nip press arrangements typically include a backing roll and a press shoe having a concave surface which cooperates with the backing roll for defining therebetween an extended nip for the passage therethrough of the web. The present invention includes a combination of a typical roll couple press followed by a first and second extended nip press. However, the present invention is unique in that the press apparatus includes a center roll which is common to the roll nip and both of the extended nips. Such an arrangement greatly reduces the overall cost of the press apparatus so that only one deflection compensated center roll is required. Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings. SUMMARY OF THE INVENTION The present invention relates to a press apparatus for pressing water from a formed web. The apparatus includes a press frame and a center roll which is rotatably supported by the frame. An upstream roll cooperates with the center roll for defining therebetween a roll nip for the passage therethrough of the web. The arrangement is such that a first portion of water is removed from the web when the web extends through the roll nip. An extended nip press shoe is disposed downstream relative to the roll nip. The first shoe defines a first concave surface which cooperates with the center roll for defining therebetween a first extended nip for the passage therethrough of the pressed web. The arrangement is such that a second portion of water is removed from the web when the pressed web extends through the first extended nip. A second extended nip press shoe is disposed downstream relative to the first shoe. The second shoe defines a second concave surface which cooperates with the center roll for defining therebetween a second extended nip for the passage therethrough of the pressed web. The arrangement is such that a third portion of water is removed from the web when the pressed web extends through the second extended nip. In a more specific embodiment of the present invention, the press frame rotatably supports the upstream roll. Also, the center roll comes into direct surface contact with a first side of the web. Additionally, the center roll is a deflection compensated roll. The press apparatus according to the present invention also includes a press felt which extends through the first roll nip. The arrangement is such that the web is disposed between the press felt and the center roll during passage of the web through the roll nip. Furthermore, the press apparatus according to the present invention includes a looped bearing blanket which slidably cooperates with the first press shoe. The bearing blanket supports and guides the web during passage of the web through the first extended nip. The arrangement is such that the web is disposed between the bearing blanket and the center roll during passage of the web through the first extended nip. More specifically, a first side of the web comes into direct surface contact with the center roll during passage of the web through the first extended nip. Also, the bearing blanket slidably cooperates with the second press shoe. The bearing blanket supports and guides the web during passage of the web through the second extended nip. More specifically, the first side of the web comes into direct surface contact with the center roll during passage of the web through the second extended nip. Additionally, a lead-in roll is disposed downstream relative to the second extended nip and a dryer felt extends around the lead-in roll. The arrangement is such that the web is transferred from the center roll to the dryer felt downstream from the second extended nip. Many modifications and variations of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings. However, such modifications and variations fall within the spirit and scope of the present invention as defined by the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagrammatic representation of the press apparatus according to the present invention. Fig. 2 is a side elevational view of a preferred embodiment of the present invention. Similar reference characters refer to similar parts throughout tire best view of the drawings. DETAILED DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagrammatic representation of a press apparatus 10 for pressing water from a formed web W. As shown in Fig. 1 , the apparatus 1 0 includes a press frame and a center roll 1 2 which is rotatably supported by the frame. An upstream roll 1 4 cooperates with the center roll 1 2 for defining therebetween a roll nip N1 for the passage therethrough of the web W. The arrangement is such that a first portion of water is removed from the web W when the web extends through the roll nip N1 . A first extended nip press shoe 1 6 is disposed downstream relative to the roll nip N1 . The first shoe 1 6 defines a first concave surface 1 8 which cooperates with the center roll for defining therebetween a first extended nip N2 for the passage therethrough of the pressed web W. The arrangement is such that a second portion of water is removed from the web W when the pressed web W extends through the first extended nip N2. A second extended nip press shoe 20 is disposed downstream relative to the first shoe 1 6. The second shoe 20 defines a second concave 22 surface which cooperates with the center roll 1 2 for defining therebetween a second extended nip N3 for the passage therethrough of the pressed web W. The arrangement is such that a third portion of water is removed from the web when the pressed web extends through the second extended nip N3. Fig. 2 is a more detailed side elevational view of the preferred embodiment of the present invention. As shown in Fig. 2, the frame 24 rotatably supports the upstream roll 14 and the center roll 12 comes into direct surface contact with a first side 26 of the web W. Preferably, the center roll 12 is a deflection compensated roll otherwise known as a crown compensated roll. The press apparatus 10 also includes a press felt F which extends through the roll nip N1 . The arrangement is such that the web W is disposed between the press felt F and the center roll 12 during passage of the web W through the roll nip N1 . A looped bearing blanket 28 slidably cooperates with the first press shoe 16. The bearing blanket supports 28 and guides the web W during passage of the web W through the first extended nip N2. The arrangement is such that the web W is disposed between the bearing blanket 28 and the center roll 12 during passage of the web W through the first extended nip N2. As is well known in the art, the first extended nip N2 includes a press felt 30 disposed between the bearing blanket 28 and the web W. Alternatively, the extended nip N2 may be double felted in which a press felt is disposed on both sides of the web W during passage through the first extended nip N2. In a preferred embodiment of the present invention, the first side 26 of the web W comes into direct surface contact with the center roll 12 during passage of the web W through the first extended nip N2. In the aforementioned arrangement, only one press felt 30 is included and such press felt is disposed between the bearing blanket 28 and the first press shoe 16. Additionally, the bearing blanket 28 slidably cooperates with the second press shoe 20. The bearing blanket 28 supports and guides the web W during passage of the web W through the second extended nip N3. In the arrangement shown in Fig. 2, the first side 26 of the web W comes into direct surface contact with the center roll 12 during passage of the web W through the second extended nip N3. Additionally, the press apparatus as shown in Fig. 2 includes a lead- in roll 32 which is disposed downstream relative to the second extended nip N3. Also, a dryer felt 34 extends around the lead-in roll 32, the arrangement being such that the web W is transferred from the center roll 12 to the dryer felt 34 downstream from the second extended nip N3. The present invention provides an extremely compact press arrangement which not only enables the removal of a considerably amount of water from the web prior to the web being guided through the dryer section but also eliminates the need for more than one compensated center roll.

Claims: WHAT IS CLAIMED IS: 1 . A press apparatus for pressing water from the formed web, said apparatus comprising: a press frame; a center roll rotatably supported by said frame; an upstream roll cooperating with said center roll for defining therebetween a roll nip for the passage therethrough of the web, the arrangement being such that a first portion of water is removed from the web when the web extends through said roll nip; a first extended nip press shoe disposed downstream relative to said roll nip, said first shoe defining a first concave surface which cooperates with said center roll for defining therebetween a first extended nip for the passage therethrough of the pressed web, the arrangement being such that a second portion of water is removed from the web when the pressed web extends through said first extended nip; and a second extended nip press shoe disposed downstream relative to said first shoe, said second shoe defining a second concave surface which cooperates with said center roll for defining therebetween a second extended nip for the passage therethrough of the pressed web, the arrangement being such that a third portion of water is removed from the web when the pressed web extends through said second extended nip. 2. A press apparatus as set forth in claim 1 wherein said press frame rotatably supports said upstream roll. 3. A press apparatus as set forth in claim 1 wherein said center roll comes into direct surface contact with a first side of the web. 4. A press apparatus as set forth in claim 1 wherein said center roll is a deflection compensated roll. 5. A press apparatus as set forth in claim 1 further including: a press felt which extends through said roll nip, the arrangement being such that the web is disposed between said press felt and said center roll during passage of the web through said first roll nip. 6. A press apparatus as set forth in claim 1 further including: a looped bearing blanket slidably cooperating with said first press shoe, said bearing blanket supporting and guiding the web during passage of the web through said first extended nip, the arrangement being such that the web is disposed between said bearing blanket and said center roll during passage of the web through said first extended nip. 7. A press apparatus as set forth in claim 6 wherein a first side of the web comes into direct surface contact with said center roll during passage of the web through said first extended nip. 8. A press apparatus a set forth in claim 6 wherein: said bearing blanket slideably cooperates with said second press shoe, said bearing blanket supporting and guiding the web during passage of the web through said second extended nip. 9. A press apparatus as set forth in claim 1 wherein: a first side of the web comes into direct surface contact with said center roll during passage of the web through said second extended nip. 10. A press apparatus a set forth in claim 1 further including: a lead-in roll disposed down relative to said second extended nip; a dryer felt extending around said lead-in roll, the arrangement being such that the web is transferred from said center roll to said dryer felt downstream from said second extended nip.

Inventors: UNSWORTH NEIL, UNSWORTH, NEIL
Applicants: BELOIT TECHNOLOGIES INC, BELOIT TECHNOLOGIES, INC.
Application year: 1998
Main classification: D21F3
IPC codes: D21F3