PRESS ARRANGEMENT FOR A MOVING WEB

Abstract: The invention concerns a press arrangement for a moving web (2). The arrangement comprises a press zone formed between a cylindrical press roll (4) and a glide belt (6), which is slidingly supported by, and wraps a shoe (8) so formed that it makes the glide belt contact a part of the circumference of the roll (4) to form the nip. Supply mechanisms (10, 12) are provided to supply lubricant for a lubricating film between the glide belt and the shoe, and the shoe (8) is supported by a counter roll (14), which is situated on the opposite side of the shoe relative the press roll (4). The side (15) of the shoe (8) facing the counter roll (14) is non-concave.

Description: Press arrangement for a moving; web Technical field * ,' The present invention concerns a press arrangement for a moving web, comprising a cylindrical roll which forms a press zone with a glide belt supported by a shoe so formed that it brings the glide belt into press contact with a part of the roll circumference to form a nip and including lubri¬ cating means for obtaining a lubricating film between the belt and the shoe, and a counter roll located on the opposite side of the shoe from the press roll. Technical stand In prior art, a press arrangement is known thru EPO pub¬ lication 0147352 wherein the surface of the shoe in contact with the counter roll is concave and follows the contour of the counter roll. Thus the shoe is locked in a definite po¬ sition between the press- and counter- rolls and consequently cannot be adjusted. Moreover, at least one of the rolls has to be of the deflection compensating type in order to achieve an even load. ' distribution along the width. Such rolls are very expensive * Examples of the general technical stand are also divul¬ ged thru DE Offenlegungssbhrift 3 17 455 and EPO publication 0070869. Description of the invention One main purpose with the present invention is to a- chieve a press arrangement of the general type indicated in the introduction which makes it possible to adjust the po¬ sition of the shoe around the center line of the press roll. Another purpose is to obtain a press arrangement which can be realized with regular and thus relatively inexpensive rolls. This has been achieved in the present invention by ar non—concave contour of the shoe on the sxue uowarus one counter roll. To compensate for deflection of the press- and counter- rolls there are in a preferred embodiment, loading arrange- ^ ' " ments inside the shoe to deform it so as to compensate for roll deflection and achieve desired load distribution through- ou-fc the width of the pressure zones between the shoe and the rolls. In order to achieve a perfect gliding support for the belt on the shoe the surface of the shoe in the area of the nip is in continuous contact with the belt via a lubricating film,from the entrance of the nip and the lubricating means including openings for introducing the lubricant under pres¬ sure in the load zones and canals for pressure equalization and removal of lubricant. In a preferred' embodiment of the invention the shoe is adjustable within limits around the center line of the press roll. This allows adjustment to a desired pressure profile in the direction of motion in the nip. Brief description of the drawings The invention shall now be elucidated in the following with reference to schematically illustrated arrangements on the attached drawings. Thus on the drawings fig. 1' is an endview of the embodiment of the invention as a partial crossection, fig. 2 is a sideview of the mechanism in accordance with fig. t as a partial transverse vertical section, fig. 3 is a transverse vertical section of shoe in ac¬ cordance with the invention, to illustrate the flow of lub¬ ricant, fig. 4 is a partial endview of the embodiment, where the crossectionof the upper part of the shoe is shown to il- lustrate the introduction of lubricant to the nip area between the press roll and the shoe, and fig. 5 shows an endview of an embodiment of the mecha¬ nism according to the invention to illustrate the adjustabi¬ lity of the shoe around the centerline of the press roll. Description of preferred embodiments In the various drawings identical reference numbers are used to indicate the same or similar details. Pigs. 1 and 2 show a press arrangement for a moving web 2. The arrangement includes a pressnip for receiving the moving web, formed between a cylindrical press roll 4 and a feliδe belt 6. The glide belt is slidingly supported on and wraps a shoe 8 with such a form that it makes the glide belt follow a part of the circumference of roll 4 to form the nip. Supply mechanisms 10 are provided to suppl lubricant for a lubricating film via canals 12 between the glide belt 6 and shoe 8. The shoe8issupported by counter roll T4 which is si¬ tuated on the opposite side of the shoe relative to the pres roll 4, whereby the side of the shoe 8 facing the counter ro 14 is non-concave. Inside the shoe 8 there are generally with 18 indicate loading mechanisms to enable deforming of the shoe to compen sate for deflection of the press roll 4 and the counter roll T in operation, so that desired loads always are maintained throughout the width. These loading mechanisms 16 may be e.g. pressure cylinders or bellows. To illustrate the prin¬ ciple, a number of bellows 18 along the width of the shoe 8 are shown in fig. 2. Arrows 20 indicate the external loads on the roll journals' 22, which cause said rolls to deflect i operation. One embodiment of the nip area,, as well as lubricant supply to the arrangement according to the invention shall now be described in more detail with reference to figs. 3 an 4. The side of the shoe 8 which faces the outside 24 of the glide belt 6 and encompasses the segment 26 which forms the nip is in unbroken contact with thB glide belt 6 via the lub ricating film, at least in the transition areas indicated by arrows 28. A supply duct 30 for lubricant is connected with nozzles 32 for the supply of lubricant under pressure betwee the shoe 8 and glide belt 6 in the nip area. A further supp duct 34 with nozzles 36, as well as equallizing canals 38 ar also show . The duct 30 is connected to a lubricant supply pipe 40, whereby the corresponding return pipe is shown at 42. With 44 is indicated an endring which rotates with the glide belt. The endring 44 is fixedwith a connection including a stσpring 46 and a " boIt-48sεreved into the flange 50 on the shoe 8.. The shoe 8 is further adjustable within limits around the centerline 51 of the press roll 4 which is schematically illustrated in fig. 5 with arrow 52. This adjustment of the shoe 8 can be realized in a manner not shown here by intro¬ ducing forces on the endflanges 50. The adjustability of the shoe 8 makes it possible to optimize web geometry be¬ fore and after the nip, as well as to influence the pressure profile in the nip. The latter is demonstrated by a pressure diagram 54 drawn onto the figure. When practical solutions of details in the press arran¬ gement according to the invention have not been described more comprehensively, they fall within known or customary practice in the art to which this invention pertains and are easily perceived by the expert. The invention can be applied e. g. to remove water from a moving web i a papermachine, whereby the web is fed into the nip in a conventional manner together with one or two felts which receive the water. Another area of use is surface finishing of the web further on in the process.

Claims: Claims f. Press arrangement for a moving web (2), com¬ prising a press nip for receiving the moving web, formed between a cylindrical press roll (4) and a glide belt (6), which is slidingly supported by, and wraps a shoe (8) having such a form that it makes the belt contact a part of the circumference of the roll (4) to form the nip, whereby supply mechanisms (TO, 112) are provided to supply lubricant for a lubricating film (T4) between the belt and the shoe, and the shoe (8) is supported by a counter roll (14),- which is situated on the opposite side of the shoe relative the press roll (4), characterized in that the side (15) of the shoe (8) towards the counter roll (14) is non- concave. 2. Press arrangement according to claim 1 , character¬ ized by loading mechanisms (16) inside the shoe(8) for de¬ forming the shoe to compensate for deflection of the press roll (4) and the counter roll (14) In operation, so that desired loads always are maintained throughout the width. 3» Press arrangement according to claims 1 or 2, Characterized In that the shoe (8) is adjustable within limits around the centerline (51) σf the press roll (4). 4» Press arrangement according to anyone of the above claims, characterized in that the side of the shoe (8) which faces the outside (24) of the glide belt (6) and encompasses the segment (26), which forms the nip, Is in unbroken contact with the glide belt (6) via the • lubricating film, at least in the transition areas of the nip section, and that said supply mechanisms (30) include nozzles (32) for the supply of lubricant under pressure between the shoe (8) and glide belt (6) In the nip area as well as canals for pressure equalization and removal of lubricant. AMENDED CLAIMS [received by the International Bureau on 18 June 1992 (18.06.92); original claim 1 amended; other claims unchanged (1 page)] 1. Press arrangement for a moving web (2), con- r si y a press ni fomed between a c lindrical pres.- rcll (4) and a glide belt (6), which is slidingl3 r sup¬ ported by, and wraps a shoe (8) having such a fom that it makes the belt contact a part of the circumference of the roll (4) to fom the nip, whereby supply mecha¬ nisms (10,12) are provided to supply lubricant for ε lubricating film between the belt and the shoe, and the shoe (8) is supported by a counter roll (14), which iε situated on the opposite side of the shoe relative the press roll (4), characterized in that the side (15) c the shoe (8) towards the counter roll 1 ) Is non-con- cave. 2. Press arrangement according to claim 1 , charac¬ terized by loading mechanisms (16) inside the shoe (8; for deforming the shoe to compensate for deflection of the press roll (4) and the counter roll (14) in opera¬ tion, so that desired loads always are maintained throuch- out the width. 3. Press arrangement according to claims 1 or 2, characterized in that the shoe (-°) is adjustable withir. linits around the centerline (51) of the press roll ) . 4. Press arrangement according to anyone of the above claims, characterized in that the side cf the shoe (8) which faces the outside (24) of the glide belt (6) and encompasses the segment (26), which forms the nip, iε unbroken contact with the glide belt (6) via. the lubricating film, at least ir. the transition areas cf the nip section, and that said supply mechanisms ' "; include nozzles (3 " 2) for the supply cf lubricant under "cressure between the shoe (B) and rrlide belt (£} ir. τhe nip area as well as canals for pressure equalization and. removal cf lubricant;.

Inventors: NYKOPP ERIK, NYKOPP, ERIK
Applicants: NYKOPP ERIK, NYKOPP, ERIK
Application year: 1992
Main classification: D21F3
IPC codes: D21F3