DE102007025816A1 - roll shell - Google Patents

Abstract

The invention relates to a roll shell for a pressing device for dewatering a paper, board, tissue or another fibrous web (1) in a machine for producing and / or finishing the same, the outer circumferential surface approximately in the circumferential direction (9) extending grooves (4 ), wherein axially adjacent grooves (4) are arranged offset in the same direction and by the same amount to each other. In this case, the economical production of the grooves (4) and the lowest possible marking by the grooves (4) should be ensured by the fact that the amount of the offset is between 10 and 50% of the groove length.

Description

The The invention relates to a roll shell for a pressing device for dewatering a paper, board, tissue or a paper another fibrous web in a machine for manufacturing and / or Refinement of the same, the outer surface has approximately circumferentially extending grooves, wherein axially adjacent Grooves in the same direction and offset by the same amount to each other are arranged.

Such roller shells are already out of the DE 197 52 725 known and allow a gentle, but intensive drainage.

At the Entering the groove in the press nip, the pressure builds up through the Connection to the atmospheric pressure of the environment only slowly on. If the groove exceeds the press nip end, then comes it to a pressure drop, as a result, injected water from the groove What is their water absorption on re-entry in the press nip and thus also the drainage performance increases.

From Disadvantage, however, are the remaining in the circumferential direction between the grooves Webs leading to significant marks in the fibrous web as a result of uneven hydraulic pressure can.

Furthermore the production of these grooves is very expensive.

The The object of the invention is therefore to reduce the production costs for to reduce these grooves as well as possible markings too Reduce.

According to the invention was solved the problem by the fact that the amount of offset between 10 and 50% of the groove length.

Thereby not only does a uniform groove arrangement arise, but it can also be relatively when milling the grooves many grooves starting on an axial generatrix at the same time be milled with a single operation.

Advantageous it is when the amount of offset is 20% or 25% or 33% is. Accordingly, every 3 to 5 grooves begins on the same axial generatrix. In the interest of a large open space of the roll mantle should be the distance between in the circumferential direction adjacent grooves between 5 and 15 mm. In the same context should the axial distance between adjacent grooves between 2 and 4 mm.

to Ensuring a high water absorption capacity should the grooves have a width between 0.4 and 2 mm and the depth of the grooves between 0.5 and 2 mm, preferably between 1 and 1.5 mm.

This Axial side walls of the grooves can be vertical or slightly inclined. You can also touch be.

Around the risk of cracks in the transition between the To minimize sidewalls and the groove bottom, the Nutgrund be formed in the axial direction of a circular arc whose Radius between 0.2 and 1 mm, preferably between 0.5 and 0.8 mm is located.

to Avoiding marks on the fibrous web due to abrupt transitions at the groove ends, the groove bottom should be at the groove ends in the circumferential direction are formed by a circular arc whose radius is between 30 and 150 mm, preferably between 60 and 100 mm.

there It has proven to be advantageous if the grooves in the circumferential direction have a length between 50 and 150 mm. Furthermore is a backflow of the absorbed by the groove Water in the direction of the press nip impeded when the grooves in the circumferential direction have a length between 20 and 60% of the length of the press nip corresponds to that of the roll shell forms with a counter-roller.

to Enlargement of the open surface of the roll mantle and thus the water storage volume, it may be advantageous if the roll shell has blind holes, these being between the Grooves and / or can lie in the grooves.

It may also be advantageous, the large water absorption capacity grooves with improved drainage behavior to combine the grooves by the roll shell in addition to over has the entire roll circumference extending grooves.

ever according to the type of fibrous web to be drained and the amount of water It may be advantageous if the grooves axially between the Grooves and / or at least one groove zone with several axially adjacent arranged grooves is present.

The Arrangement of at least one groove zone can at least at the roll ends be beneficial.

To ensure sufficient flexibility, stability and resilience of the roll mantle, this should consist of flexible material and preferably reinforcing means of fabric, Contain fibers or threads.

following the invention should be closer to an embodiment be explained. in the attached drawing shows:

1 a schematic cross section through a shoe press;

2 : A partial plan view of a roll shell 2 and

3a and 3b a longitudinal and cross section through a groove 4 ,

At the in 1 shown pressing arrangement is the fibrous web 1 together with a water-absorbing and water-permeable drainage band on both sides 11 . 12 in the form of a press felt by that of a shoe press roll 3 and a counter roll 6 led formed press nip.

The case of the fibrous web 1 Pressed water is removed from the drainage tapes 11 . 12 taken and partly to the roll coats 2 issued. To increase the water absorption capacity, at least the roll shell 2 the shoe press roll 3 profiled executed.

In the interest of gentle but intensive dewatering of the fibrous web 1 the press nip is extended. Therefore has the shoe press roll 3 a flexible roll shell 2 made of fiber-reinforced plastic, which of a contact pressure element 10 with concave pressing surface to the cylindrical counter-roller 6 is pressed.

The profiling of the roll shell 2 is essentially from in the circumferential direction 9 extending grooves 4 formed, but also by blind holes and / or in the circumferential direction 9 extending, continuous grooves can be added.

To ensure the most uniform possible drainage, the axially adjacent grooves 4 viewed in the axial direction in the same direction as in 2 shown in the circumferential direction 9 arranged offset by 33% of the groove length to each other. This starts every third axially adjacent groove 4 on the same axial generatrix, so that several of these grooves 4 can be milled simultaneously when using a side milling cutter.

While doing the the distance between in the circumferential direction 9 adjacent grooves 4 is between 5 and 15 mm, the axial distance between adjacent grooves 4 between 2 and 4 mm.

To create a large water storage capacity have the grooves 4 a width between 0.4 and 2 mm and a depth between 1 and 1.5 mm.

The side walls 5 the grooves 4 are substantially vertical and open into a groove bottom 7 which minimizes stresses in the roll shell 2 according to 3a viewed in the axial direction is formed by a circular arc whose radius is between 0.5 and 0.8 mm.

To create the most gradual transitions between the grooves 4 and the Nutstegen is the groove bottom 7 at the Nutenden 8th in the circumferential direction 9 considered to be formed by a circular arc whose radius is between 60 and 100 mm. This supports the most uniform possible drainage behavior and allows short groove webs between the grooves 4 in the circumferential direction 9 ,

So that the water in the grooves 4 in the press nip can not flow back in the direction of the press nip, have the grooves 4 in the circumferential direction 9 a length which corresponds to between 20 and 60% of the length of the press nip, here specifically between 50 and 150 mm.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19752725 [0002]

Claims (20)

Roll shell for a press device for dewatering a paper, board, tissue or other fibrous web ( 1 ) in a machine for producing and / or finishing the same, the outer circumferential surface approximately in the circumferential direction ( 9 ) running grooves ( 4 ), wherein axially adjacent grooves ( 4 ) are arranged offset in the same direction and by the same amount to each other, characterized in that the amount of the offset is between 10 and 50% of the groove length. Roll shell according to claim 1, characterized in that the amount of the offset is 20%. Roll shell according to claim 1, characterized in that that the amount of the offset is 25%. Roll shell according to claim 1, characterized in that that the amount of the offset is 33%. Roll shell according to one of the preceding claims, characterized in that the distance between in the circumferential direction ( 9 ) adjacent grooves ( 4 ) is between 5 and 15 mm. Roll shell according to one of the preceding claims, characterized in that the grooves ( 4 ) have a width between 0.4 and 2 mm. Roll shell according to one of the preceding claims, characterized in that the axial distance between adjacent grooves ( 4 ) is between 2 and 4 mm. Roll shell according to one of the preceding claims, characterized in that the depth of the grooves ( 4 ) is between 0.5 and 2 mm, preferably between 1 and 1.5 mm. Roll shell according to one of the preceding claims, characterized in that the groove bottom ( 7 ) is formed in the axial direction of a circular arc whose radius is between 0.2 and 1 mm, preferably between 0.5 and 0.8 mm. Roll shell according to one of the preceding claims, characterized in that the groove bottom ( 7 ) at the Nutenden ( 8th ) in the circumferential direction ( 9 ) is formed by a circular arc whose radius is between 30 and 150 mm, preferably between 60 and 100 mm. Roll shell according to one of the preceding claims, characterized in that the grooves ( 4 ) in the circumferential direction ( 9 ) have a length between 50 and 150 mm. Roll shell according to one of the preceding claims, characterized in that the grooves ( 4 ) in the circumferential direction ( 9 ) have a length corresponding to between 20 and 60% of the length of the press nip, the roll shell ( 2 ) with a counter-roller ( 6 ). Roll shell according to one of the preceding claims, characterized in that the roll shell ( 2 ) Has blind holes. Roll shell according to claim 13, characterized in that the blind holes between the grooves ( 4 ) lie. Roll shell according to claim 13 or 14, characterized in that the blind holes in the grooves ( 4 ) lie. Roll shell according to one of the preceding claims, characterized in that the roll shell ( 2 ) has grooves extending over the entire circumference of the roll. Roll shell according to claim 16, characterized in that the grooves are axially between the grooves ( 4 ) are arranged. Roll shell according to claim 16 or 17, characterized that at least one furrow zone with several axially adjacent arranged grooves is present. Roll shell according to claim 18, characterized in that that at least one furrow zone is present at the roll ends. Roll jacket according to one of the preceding claims, characterized in that it consists of flexible material and preferably reinforcing means of fabric, fibers or threads.