GB2268790A

GB2268790A - Improvements in or relating to a roller.

Info

Publication number: GB2268790A
Application number: GB9314620A
Authority: GB
Inventors: Heinz-Willi Berger; Helmut Simon
Original assignee: Eduard Kuesters Maschinenfabrik GmbH and Co KG
Current assignee: Eduard Kuesters Maschinenfabrik GmbH and Co KG
Priority date: 1992-07-14
Filing date: 1993-07-14
Publication date: 1994-01-19
Anticipated expiration: 2013-07-14
Also published as: DE4223102C1; FR2693669B1; GB9314620D0; FI933174A0; FI933174L; FI110138B; GB2268790B; FR2693669A1

Abstract

A roller in the form of a "floating" roller comprises a rotatable shell 1, fig 1, and a fixed beam 4 which extends through the shell so as to be spaced from the internal surface of the shell. A longitudinal chamber 8 is defined in the space 7 between the beam and the internal surface of the shell, this chamber being fillable with pressure fluid and being bounded by transverse end seals 11 and longitudinal seals 10 extending along the beam. Each longitudinal seal 10 comprises a sealing strip 21, fig 3, which is held in position relative to the beam by means of a support component which is formed separately from but is mountable upon the beam. The support component may comprise a support stripe 20 mountable within a longitudinal groove 31 formed in the beam with clamping elements 40 being provided to retain the support strip within the groove. <IMAGE>

Description

2268790 DESCRIPTION OF INVENTION "IMPROVEMENTS IN OR RELATING TO

A.ROLLERY9 THE PRESENT INVENTION relates to a roller of the type which is sometimes referred to as a "floating roller". This type of roller has an elongate hollow shell which is rotatable about its longitudinal axis and a non- rotatable beam which extends through the shell at a position spaced from the internal surface of the shell, the ends of the beam being appropriately supported at positions outside of the shell. The beam is provided with longitudinal and transverse seals which define at least one longitudinal chamber in the space between the shell and the beam, this chamber being f illable with pressure fluid by way of which the shell is supported upon the beam.

A roller of this kind is known from DE-PS 11 93 739 In this case the longitudinal seals comprises sealing strips of substantially L-shaped cross-section, the shorter limb of which bears against the internal surface of the shell and the longer limb of which engages within an undercut shoulder formed on the beam. The undercut in the bean comprises a milled longitudinal groove.

Rollers of this type are used in a calender where co-operating rollers are positioned adjacent each other so as to def ine a nip, the calender being used, inter alia, for the pressure treatment of webs of materials such as paper, textile or plastic sheeting. For the treatment of paper, a roller of this type may have a length of up to 10 metres and a diameter of up to 1 metre. The beam of such a roller is a very large and heavy component. Milling longitudinal grooves in both sides of such a component to 2 accommodate part of the longitudinal seals is technically quite difficult and is a time-consuming operation.

The present invention seeks to address the problem outlined above and to reduce the effort involved in producing a support for the longitudinal sealing strips on the beam.

According to the present invention there is provided a roller comprising an elongate, hollow shell forming the operative periphery of the roller, the shell being rotatable about its longitudinal axis and a nonrotatable bean extending through the shell so as to be spaced from the internal surface of the shell, the beam being supported at its ends externally of the shell, there being at least one longitudinal chamber formed in the space between the shell and the beam, the longitudinal chamber being bounded by transverse end seals and longitudinal seals which extend along the bean and engage the internal surface of the shell, the longitudinal chamber formed in the space between the shell and the beam being fillable with pressure fluid, the longitudinal seals each comprising a sealing strip which is held in position relative to the beam by means of a support, the support f or each seal comprising a component formed separately from and mountable upon the beam.

Providing a component which is f ormed separately from the beam itself for supporting the longitudinal seals means that it is not necessary for the relatively complex shape which is required to support the longitudinal seals to be formed in the beam itself; this shape can, instead, be f ormed in the separate component which supports the longitudinal seals.

3 Preferably the support comprises an elongate support strip and the beam def ines a longitudinal groove within which the support strip can be mounted.

The support strip may be formed as a plurality of sections mountable within the longitudinal groove in the beam to form a "continuous" support strip. Thus, if desired, the elongate strip may consist of relatively short individual sections which can be assembled on the beam to form a continuous support strip over the entire length thereof.

Conveniently the longitudinal groove in the beam is of substantially rectangular cross-section and the support strip has a portion of substantially corresponding crosssection. The longitudinal groove in the beam can therefore be of a simple cross-section which may be produced quickly and easily by a milling operation.

Advantageously the support strip is mounted within the longitudinal groove in the beam by way of a clamping arrangement.

Preferably the clamping arrangement comprises rotatable clamping elements disposed in recesses formed in the support strip. the recesses in the support strip each defining an opening directed towards one surface of the longitudinal groove when the support strip is mounted within the longitudinal groove, the arrangement being such that the clamping elements bear against said one surface of the longitudinal groove and press the support strip against an opposed surface of the groove, thereby clamping the support strip within the groove.

4 Conveniently the support strip defines a plurality of said recesses at positions distributed at intervals along the length of the support strip.

Advantageously the clamping elements each take the form of "thick" discs or cams having a convex peripheral surface, each clamping element exerting a clamping force at its periphery in a substantially radial direction, the "diameter" (D) of each element varying around the periperhy of the element.

The term "thick disc" denotes a disc, the diameter of which is of substantially the same order of magnitude as its thickness. Mathematically the disc represents a cylinder, i.e. its peripheral surface is formed by parallel generatrices, although the cross-section of the disc is not circular but is irregular with the distance between parallel surfaces tangential to the periphery of the crosssection depending upon the rotary position of the disc. Thus, rotation of the disc enables a larger "diameter" to be moved into a position transversely of the longitudinal groove in the beam so that the support strip is clamped fast within the longitudinal groove.

Preferably each clamping element is formed with a non-circular hole to receive a tool adapted to rotate the clamping element.

The non-circular holes for receiving a rotating tool may, f or example, be hexagonal so as to receive a hexagonal key adapted to turn the clamping elements and f ix the support strip in position upon the beam.

The longitudinal chamber f ormed in the space between the shell and the beam may be of semi-cylindrical or dish-shaped form.

The longitudinal sealing strips may each have a first longitudinal edge which engages in the separate support component and a second longitudinal edge which engages the internal surface of the shell.

In order that the present invention may be more readily understood and so that further features thereof may be appreciated the invention will now be described by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a longitudinal cross-section through a "floating roller"; Figure 2 is an enlarged elevation of a clamping strip used in the roller of Figure 1; Figure 3 is an enlarged partial cross-section showing that region of the roller of Figure 1 where a longitudinal seal is provided; Figure 4 shows, on the left, an elevation of the longitudinal seal arrangement as seen from the left in Figure 3, and shows, on the right, a sectional view on the line IV-IV in Figure 3; Figure 5 is an enlarged elevation of a clamping element used with the clamping strip of Figure 2; and 6 Figure 6 is a cross-sectional view taken on the line VI-VI in Figure 5.

Referring initially to Figure 1 of the drawings a roller having the general reference number 100 comprises a rotatable shell 1 which defines the operative roller periphery 2 and a beam 4 which extends through the shell 1 at a position spaced from the internal surface 5 of the shell, the shell 1 being supported upon the bean 4 by means of bearings 3 disposed within the shell adjacent its opposite ends. The beam 4 projects beyond the'ends of the shell 1 and is mounted, for example, in a roll stand (which is not illustrated) by means of self-aligning bearings 6 disposed on that part of the beam which projects beyond the shell. The bean 4 is held against rotation by means of a torsion bar 18.

In use the roller 1 co-operates with a further, similar roller which may or may not be a "floating type" roller in order to define a nip 9 between the periphery of the two rollers, with a web of material passing through the nip as it is subjected to a pressure treatment.

As nentioned above the beam 4 is spaced from the internal surface 5 of the shell 1, with the space being identified by reference numeral 7 in Figure 1. On that side of the roller which is adjacent the roller nip 9 when the roller is in use, a semi-cylindrical dish-shaped longitudinal chamber.8 is defined within the space 7 by means of longitudinal seals 10 mounted upon the beam at its widest point and transverse end seals 11 disposed at positions inwardly of the bearings 3. The longitudinal chamber 8 is filled with pressure fluid via conduits 12, 13. The pressure fluid exerts pressure against the internal surface 5 of the shell 1, this pressure being 7 uniform over the length of the longitudinal chamber 8 and generating a linear force in the roller nip 9. This pressure acts, inter alia, upon the longitudinal seals 10 which are thereby subjected to a force which would tend to def lect the beam 4 downwardly over that portion of its length positioned between the bearings 3. It will be appreciated that the beam 4 may sag or be deflected in the space 7 between the bean and the internal surface 5 of the shell and in this way the shell remains unaffected i.e. it is not deflected, by the linear force generated within the roller.

The longitudinal chamber 8 need not be hermetically sealed. It is sufficient if a pressure of, for example, 10 bar can be maintained without excessive pumping. Leaks in the seals 10, 11 result in some of the pressure fluid escaping from the longitudinal chamber 8, which constitutes the pressurised chamber, and passing into the "leakage" chamber positioned around the bottom half of the beam 4 as seen in Figure 1 and from which this leakage f luid is continuously withdrawn via conduits 14, 15. Normally the leakage chamber will also be f illed with pressure f luid. Some of this pressure f luid f lows into the bearings 3 located in the region of the leakage chamber and, after passing through the bearings 3, this fluid is withdrawn via branch conduits 16.

In some cases one supply line would be sufficient to supply pressure f luid to the longitudinal chamber 8, but if the f luid is heated in order to transmit heat to the shell 1, a relatively large throughput of pressure f luid is required. In this case pressure fluid is supplied via the conduit 12 and discharged via the conduit 13 so that pressure f luid at an elevated pressure always circulates through the longitudinal chamber 8.

8 one longitudi nal seal 10 is shown in detail in Figure 3 of the drawings. The seal comprises a sealing strip 21 which is of substantially L-shaped cross-section. The L-shaped sealing strip has a shorter limb 22 having a free edge 35 which may be considered to form a "doctor blade" and which bears against the internal surface 5 of the shell 1 and a longer limb 23 having a free edge 26 which engages within an undercut portion 24 in the form of a longitudinal groove provided in a separate support strip 20. As seen in Figure 3 the right hand portion of the support strip 20 is of substantially rectangular crosssection and is designed to be received within a longitudinal groove 31 of corresponding shape formed in the beam 4. This rectangular portion of the support strip 20 has opposed, shorter sides 25, 26 and opposed longer sides 27, 28. on the longer side 28 which faces the internal surface 5 of the shell 1 an outwardly directed projection 29 is provided in the region of the shorter side 26, this projection defining the undercut portion 24 on its boundary 30 which faces the other shorter side 25.

As mentioned above, the beam 4 defines a longitudinal groove 31. There are in fact two longitudinal grooves 31, the grooves being formed on opposite sides of the beam. The grooves 31 are of substantially rectangular cross-section and each accommodate the rectangular portion of a support strip 20 in such a way that opposed flanks or surfaces 37, 39 of the longitudinal groove 31 are positioned opposite the shorter sides 25, 26 of the rectangular cross-section portion of the support strip 20.

A spring-steel strip 32 is clamped between the shorter side 25 of the rectangular portion of the support strip 20 and the adjacent flank 37 of the groove 21 in the beam 4. The spring-steel strip 32 bears against the 9 external surface of the shorter limb 22 of the L-shaped sealing strip 21 and holds the strip 21 securely in position with the shorter limb 22 abutting the internal surface 5 of the shell 1 and with the longer limb 23 retained in the undercut portion 24. When the longitudinal chamber 8 is filled with pressure fluid, the pressure in this chamber acts on the sealing strip 21 in the same way as the spring-steel strip 32 and applies a pressure-related force to the strip which urges the sealing strip 21 against the internal surface 5 of the shell.

Figure 2 shows the support strip 20 in elevation, as seen from the left in figure 3 of the drawings.

The bottom edge of the support strip 20 defines a plurality of bores 33 at intervals of, for example, 100 mm along its length. The axis of each of the bores 33 extends parallel to the shorter sides 25, 26 of the rectangular portion of the support strip. The bores extend through the projection 29 which defines the undercut portion 24 behind which one edge of the sealing strip 21 is retained. In the embodiment illustrated the bores 33 are blind bores, that is to say there is a thin wall 45 at the base of each bore 33 at the back of the support strip 20. The bores 3 3 intersect the bottom or shorter side 26 of the support strip, that is to say they each have an opening 34 at the bottom of the support strip 20. Each bore 33 is provided with a clamping element 40 in the form of a "thick" steel disc designed to be accommodated within the bore and to be rotatable about an axis parallel to the axis of the bore. With the support strip 20 located in the groove 31 in the beam 4, as illustrated in Figure 3, each clamping element 40 within a respective bore 33 engages against an upper region 38 of its bore 33 and, at an opposed position, engages against the lower flank 39 of the groove 31 in order to urge the support strip 20 upwards (as seen in Figures 3 and 4) so that it is firmly clamped in position within the groove 31. Each clamping element 40 effectively acts as a cam, in a manner as will be described below, and the clamping effect is produced by rotating the clamping element using, for example, a hexagonal key engaged in an appropriately dimensioned hexagonal recess 41 provided in each of the clamping elements.

As mentioned above each clamping element 40 is formed as a "thick" steel disc having a peripheral surface 43 which is designed so as to be convex at all positions in the plane of the disc with the peripheral surface 43 being formed by parallel generatrices. In cross-section or end elevation, as seen in Figure 5, each of the clamping discs 40 is not circular but has "diameters" which vary continuously around the periphery of the disc, that is to say the distance between parallel planes tangential to the peripheral surface 9f the clamping element 40 varies with the rotary position around the surface of the disc.

Figure 5 illustrates one example of this type of arrangement of varying "diameters", with radii of the disc being measured from an imaginary centre point 44. The table beneath Figure 5 gives the radii at positions around the periphery of the disc. The radii given in the table relate to a disc f or use in a bore 33 having a 16 mm diameter, the clamping disc being introduced into the bore 33 with minimum clearance. If D is the height or distance between opposed planes tangential to the peripheral surface of the disc then it can be seen that in the case of the radii R1 and R7, D = R1 + R7 = 14.2 mm, whilst in the case of the radii R5 and R11 D = R5 + R11 = 15.8 mm.

11 Thus, if the clamping element or disc 40 is initially in position within a bore 33 such that R1 is directed towards the upper region 38 of the bore (see the right-hand half of Figure 4) and R7 is directed towards the bottom flank 39 of the groove 31 in the beam 4, then upon rotation of the clamping element or disc 40 into a position such that R11 is directed upwardly and replaces R1, and R5 is directed downwardly and replaces R7 a movement of 1.6 mm is produced. This movement acts to urge the support strip 20 upwardly so that it is pressed against the upper flank 37 of the longitudinal groove 31, thereby causing the support strip 20 to be firmly retained within the groove.

As mentioned above, each clamping element or disc 40 therefore acts in the manner of a cam, with rotation of the disc in a bore 33 generating linear movement in a direction parallel to the longer sides 27, 28 of the support strip 20. The distance between opposed parallel planes tangential to the peripheral surface of the clamping disc 40 must always be less than the diameter of the bore 33 within which it is to be accommodated, i. e. in this particular example it must be less than 16 mm. It is, of course, possible to provide a support strip 20 having bores 33 with a diameter which is less than or greater than 16 mm in which case the "radiP' of the clamping discs 40 would be varied appropriately.

It will be appreciated that the sealing strips 21 which extend along the length of the beam 4 and which serve to bound the pressurised chamber 8 are not supported directly on the bean 4 but are supported on a component which is separate from but mountable upon the beam 4 in the groove 31 formed therein. The mounting of the support strip upon the beam is effected simply, with the support strip being firmly clamped in position by rotating the 12 discs 40. This arrangement enables the relatively complex shape which is required to support the sealing strip 21 to be def ined by the separate support strip 20 and springsteel strip 32, thereby necessitating the milling of only a simple groove 31 in the beam 4 iself which can be a very large and heavy component.

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Claims

1. A roller comprising an elongate, hollow shell f orming the operative periphery of the roller, the shell being rotatable about its longitudinal axis and a nonrotatable beam extending through the shell so as to be spaced from the internal surf ace of the shell, the beam being supported at its ends externally of the shell, there being at least one longitudinal chamber f ormed in the space between the shell and the beam, the longitudinal chamber being bounded by transverse end seals and longitudinal seals which extend along the beam and engage the internal surf ace of the shell, the longitudinal chamber f orped in the space between the shell and the beam being f illable with pressure fluid, the longitudinal seals each comprising a sealing strip which is held in position relative to the bean by means of a support, the support f or each seal comprising a component formed separately from and mountable upon the beam.

2. A roller according to claim wherein the support comprises an elongate support strip and the beam defines a longitudinal groove within which the support strip can be mounted.

3. A roller according to claim 2 wherein the support strip is f ormed as a plurality of sections mountable within the longitudinal groove in the beam to form a "continuous" support strip.

4. A roller according to claim 2 or claim 3 wherein the longitudinal groove in the beam is of substantially rectangular cross-section and the support strip has a portion of substantially corresponding cross-section.

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5. A roller according to any one of claims 2, 3 or 4 wherein the support strip is mounted within the longitudinal groove in the beam by way of a clamping arrangement.

6. A roller according to claim 5 wherein the clamping arrangement comprises rotatable clamping elements disposed in recesses formed in the support strip, the recesses in the support strip each defining an opening directed towards one surface of the longitudinal groove when the support strip is mounted within the longitudinal groove, the arrangement being such that the clamping elements bear against said one surface of the longitudinal groove and press the support strip against an opposed surface of the groove, thereby clamping the support strip within the groove.

7. A roller according to claim 6 wherein the support strip defines a plurality of said recesses at positions distributed at intervals along the length of the support strip.

8. A roller according to claim 6 or claim 7 wherein the clamping elements each take the form of "thick" discs or cams having a convex peripheral surface, each clamping element exerting a clamping force at its periphery in a substantially radial direction, the "diameter" (D) of each element varying around the periperhy of the element.

9. A roller according to claim 8 wherein each clamping element is formed with a non-circular hole to receive a tool adapted to rotate the clamping element.

10. A roller according to any one of the preceding claims wherein the longitudinal chamber formed in the space between the shell and the bean is of semi -cylindrical or dish-shaped form.

11. A roller according to any one of the preceeding claims wherein the longitudinal sealing strips each have a first longitudinal edge which engages in the separate support component and a second longitudinal edge which engages the internal surface of the shell.

12. A roller substantially as herein described with reference to and as shown in the accompanying drawings.

13. Any novel feature or combination of features disclosed herein.

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