Abstract:
Roll for a paper/board machine or finishing device having an interior in which an inner tube is installed and a method for fastening the inner tube in the roll interior. The inner tube is arranged so that its outer face is spaced from the inner face of the mantle of the roll whereby a heat transfer medium can be passed into the interior of the roll and through this space in an axial direction of the roll. The inner tube includes fastenings arranged at one or more axial locations. At each axial location, at least one fastening can be positioned radially in a certain predetermined position and another fastening can be displaced freely in the radial direction.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a roll for a paper/board machine or for a paper/board finishing device and a method for fastening an inner tube in the interior of a roll of a paper/board machine or a paper/board finishing device. 
     BACKGROUND OF THE INVENTION 
     Polymer-coated rolls arranged in calenders require cooling so that they will operate optimally. By means of such cooling, attempts are made to keep the end and lateral areas of the roll at a uniform temperature so that the effect of crown formation by the effect of heat is minimized. 
     For cooling, a so-called displacement tube technique has been applied. 
     The principle of the displacement tube technique is briefly as follows: water at the required temperature is passed to the end of the roll by means of a water coupling, water circulates in the interior of the roll along a space between an inner tube and an outer tube to the opposite end of the roll, and at the opposite end of the roll there is a water coupling through which the water is passed out of the roll. The space between the inner tube and the outer tube in the roll is usually quite small. In this manner, even though the amounts of water are quite small, attempts are made to keep the flow sufficiently large in order to meet the requirement of a uniform temperature in the end and lateral areas of the roll. 
     It has been laborious and difficult to fit the inner tube and the outer tube one inside the other. First, it has been necessary to measure and to manufacture the inner tube separately for each roll because the diameters of the outer tube vary from roll to roll. Then, in the installation stage, it has been necessary to cool the inner tube with nitrogen in order to fit the tube into the interior of the outer tube. Thus, manufacturing rolls with inner tubes has been typically a time-consuming and technically and economically unfavorable procedure. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention is to provide a solution for installing an inner tube in a roll by whose means the difficulties related to the prior art methods are overcome. 
     It is another object of the present invention to provide new and improved rolls for a paper/board machine or for a paper/board finishing device. 
     It is another object of the present invention to provide new and improved methods for fastening an inner tube in an interior of a roll, especially for use in a paper/board machine or paper/board finishing device. 
     It is yet another object of the present invention to provide an inner tube for a roll which is able to be arranged in the inside of rolls having different diameters so that the inner tube does not have to be roll-specific. 
     In order to attain these objects and others, in a roll in accordance with the present invention, the inner tube, by whose means the water is forced to flow along the inner face of the mantle of the roll body, is fastened to the body mantle by fastening pistons which are installed on the inner tube with a necessary spacing in the longitudinal direction whereby three pistons are arranged in the direction of the circumference. Of the pistons in the direction of the circumference, two are fixedly installed at a proper height in connection with the installation, and one is freely moving and spring-loaded. The spring-loaded piston is constructed so that, by means of hydraulics, the piston is pressed down for the time of installation of the inner tube. The pipe systems required by the hydraulics are passed along the outer face of the inner tube, preferably to the tending-side end of the roll. The pressure required by the hydraulics is produced by means of a normal hydraulic pump (the same pump by whose means the bearing is removed/fixed). After the inner tube has been installed in the correct position, the hydraulic pressure is released, and the disk springs of the spring-loaded piston press the piston against the body mantle. By means of the fixed and the spring-loaded pistons, the inner tube is kept in its position, and vibration and bending of the inner tube are prevented. The fastening at the ends is arranged either so that separate rings attached to the flange shafts by means of hexagonal socket-head bolts, on which rings the inner tube is installed with glide fitting, or, in new projects, so that alterations are made to the cast models of the flange shaft, and the end fastening face is provided directly on the flange shaft. In this manner, separate rings are not needed. 
     Thus, one general embodiment of a roll for a paper/board machine or finishing device comprises a roll mantle defining an interior and having an inner face, an inner tube arranged in the interior of the roll mantle and having an outer face arranged at a distance from the inner face of the roll mantle, and a plurality of fastening elements (or simply fastenings) for securing the inner tube to the roll mantle. At least one fixed fastening is positioned radially in a certain predetermined position (fixed in that it includes a piston which is not movable during the installation procedure) and a displaceable fastening is arranged to be displaceable in a radial direction of the inner tube (displaceable in that it includes a component which is movable during the installation procedure). The inner tube may comprise apertures at first and second ends and the roll further comprises first and second shafts arranged at first and second ends of the roll mantle. Each shaft includes a flow passage communicating with a space between the inner face of the roll mantle and the outer face of the inner tube via the apertures in the inner tube. 
     The displaceable fastening comprises a spindle part having a head part and biasing means, e.g., a spring unit of one or more springs, for urging the head part against the inner face of the roll mantle. It may also comprise an interior space receivable of pressure fluid defined adjacent the spindle part. The biasing means are thus arranged such that upon removal of pressure fluid from the interior space (which occurs after the inner tube is installed in the interior of the roll), the head part is urged against the inner face of the roll mantle. The displaceable fastening may also comprise a piston part, whereby the interior space is defined between the piston part and the spindle part, and a sleeve defining a first interior space and a second interior space having a diameter smaller than a diameter of the first interior space and having an edge portion in the vicinity of an inlet opening of the first interior space. The sleeve defines an inside shoulder between the first and second interior spaces. The spindle part may include a rod connected to the head part and surrounded by the spring(s) of the spring unit. An intermediate disk may be arranged on the shoulder and a cotter ring may be provided to lock the disk against the shoulder. The disk includes a central opening through which the rod of the spindle part passes. The piston part includes an inner bore having threading and the rod includes a threading in engagement with the threading of the piston part. Further, the fastening may include an end disk arranged at an end of the inner bore of the piston part, and a cotter coupled to the piston part for preventing rotation of the piston part. The cotter is guided in a hole in the sleeve of the fastening. In some embodiments, the sleeve includes a duct for allowing passage of pressure fluid into and from the interior space in the fastening. 
     There are preferably two fixed fastenings. Each fixed fastening comprises a sleeve and a screw arranged in the sleeve and having an outer face adapted to be pressed against the inner face of the roll mantle. The screw is rotatable relative to the sleeve to provide adjustable extension of the screw from the sleeve, which rotation is effected prior to installation or insertion of the inner tube into the interior of the roll mantle. The screw is then locked in its position and then the inner tube is inserted into the interior of the roll. In some embodiments, the screw has a spindle part having a threaded outer surface and a backup part wider than the spindle part. The interior of the sleeve defines a wide recess and an end bore having a threading. The spindle part of the screw threadingly engages with the threading of the end bore of the sleeve. The backup part includes a curved outer face adapted to be pressed against the inner face of the roll mantle upon rotation of the screw relative to the sleeve. 
     In the method for fastening an inner tube into an interior of a roll for a paper/board machine or finishing device, at least one first fastening is arranged in the inner tube at a location along an axis of the inner tube, each first fastening having an extension projectable above the outer face of the inner tube and designed to be fixed in position during installation of the inner tube into the interior of the roll. A second fastening is arranged in the inner tube at the same axial location as the first fastening(s), the second fastening having a displaceable spindle part movable between first and second position whereby the spindle part projects further above the outer face of the inner tube in the second position (although in the first position, the spindle part does not necessarily have to project above the outer face of the inner tube). The position of the extension of each first fastening is adjusted and preferably fixed at a desired radial projecting position prior to installation of the inner tube in the interior of the roll. The inner tube is then inserted into the mantle of the roll while maintaining the spindle part of the second fastening in the first position. The spindle part of the second fastening is then displaced into the second position and urged against the inner face of the mantle, e.g., by the decompression of springs in a spring unit. 
     The spindle part of the second fastening may be maintained in the first position by coupling a pipe to the second fastening, extending the pipe to one of the ends of the inner tube and directing a medium through the pipe to cause displacement of the spindle part of the second fastening to the first position such that control of the displacement of the spindle part of the second fastening is effected from the end of the inner tube. Similarly, the spindle part of the second fastening may be maintained in the first position and caused to be displaced into the second position by coupling a pipe to the second fastening, arranging a piston part and a stationary disk in the second fastening, arranging at least one spring between a head part of the spindle part and the disk, and controlling the flow of pressure fluid through the pipe into and from a space between the disk and the piston part. When the pressure fluid flows into the space, the spindle part is moved to the first position and the at least one spring is compressed, and when the pressure fluid flows from the space, the spindle part is moved to the second position upon decompression of the at least one spring. 
     In the following, the invention will be described in detail with reference to some exemplifying embodiments of the invention illustrated in the figures in the accompanying drawing. However, the invention is by no means strictly confined to the details of the illustrated embodiments alone. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following drawings are illustrative of embodiments of the invention and are not meant to limit the scope of the invention as encompassed by the claims. 
     FIG. 1 is a longitudinal sectional view of a roll in accordance with the invention. 
     FIG. 2 is a sectional view taken along the line I—I in FIG.  1 . 
     FIG. 3A is a sectional view of one of the two fastenings in the arrangement of three-point fastening. 
     FIG. 3B shows the third fastening in the arrangement of three-point fastening, which third fastening comprises a hydraulic/spring-operated spindle. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the accompanying drawings wherein the same reference numerals refer to the same or similar elements, FIG. 1 is a longitudinal sectional view of a roll  10  in accordance with the invention. The fastening between the roll  10  and an inner tube  11  installed in the interior of the roll  10  is accomplished in accordance with the invention by means of piston elements, fastening elements or fastenings  13   a   1 ,  13   a   2  and  13   a   3  placed in certain fastening planes, each at a respective location in the axial direction of the inner tube  11 . The fastenings  13   a  are arranged preferably at the ends and in the middle of the roll so that each fastening arrangement in a plane at a point of the length of the roll  10  comprises a three-point fastening arrangement. The fastenings  13   a   1 ,  13   a   2  and  13   a   3  are arranged at a uniform angular spacing, i.e., at an angular spacing of 120°, in relation to one another on the inner tube  11  that has been installed inside the roll  10 . The fastenings  13   a   1 ,  13   a   2  and  13   a   3  in each fastening plane T 1 , T 2  and T 3  fasten the inner tube  11  in the interior space O in the roll mantle  10   a  of roll  10  against the inner face  10   a   1  of the roll mantle  10   a , i.e., secure the inner tube  11  to the roll mantle  10   a . The inner tube  11  comprises a closed inner space O 2  and closing plates E 1  and E 2  passing across the tube  11  and placed in the vicinity of the ends of the tube  11  (but not at the end of the tube  11  so that a portion of the roll mantle  10   a  remains outside of inner space O 2 ). At the ends of the tube  11 , spaces O 3  and O 4  are thus formed on the other side of plates E 1  and E 2  and the roll mantle  10   a  includes flow passages such that water or any other heat transfer medium, preferably a cooling medium, can be passed from space O 3  along the roll mantle  10   a  and then into space O 4 . More particularly, the heat transfer medium can be passed in the axial direction of roll  10  through a flow passage J 1  in the center of a shaft  10   b   1 , and shaft flange  10   c  into the space O 3 , from space O 3  through the flow passages N 1  formed at one end of the inner tube  11  into the space O 1  between the outer mantle face  11   a  of the tube  11  and the inner mantle face  10   a   1  of the roll  10  and then through the tubular space O 1  in an axial direction of the roll  10  (arrows L 1 ). The heat transfer medium is able to flow from space O 1  through the flow passages N 2  formed at the other end of the tube  11  into the space O 4 . From space O 4 , the medium may be passed through a central flow passage J 2  in the center of the shaft flange  10   c  and shaft  10   b   2  of the roll  10 . The flow can also take place in the opposite direction, in which case the heat transfer medium, such as water, is initially passed into the other end of the roll  10  through the central flow passage J 2  in the shaft  10   b   2 . 
     In FIG. 1, the flow of water in connection with the roll  10  and with its inner tube  11  is indicated by the arrows L 1 . 
     The roll  10  comprises shafts  10   b   1 ,  10   b   2  which are attached to the roll mantle  10   a  from their shaft flanges  10   c  by means of screws R,R 1 . An end ring  10   d  is attached to the flange  10   c  by means of screws R 2 , and the end of the tube  11  is fitted around the end ring  10   d . The arrangements are similar at each end of the roll  10 . 
     FIG. 2 is a sectional view taken along the line I—I in FIG.  1 . As shown in FIG. 2, the fastenings  13   a   1 ,  13   a   2  and  13   a   3  are arranged in the fastening plane T 1  so that they are coupled (engaged) both with the inner tube  11  and with the inner face  10   a   1  of the roll mantle  10   a  of the roll  10 . There is an angle of about 120° between each of the fastenings  13   a   1 ,  13   a   2  and  13   a   3 , i.e., thus, the fastening are situated with uniform angular spacing on the circumference of the inner tube  11 . As shown in FIG. 2, the two fastenings  13   a   1  and  13   a   2  are identical, and the construction of the third fastening  13   a   3  differs from the fastenings  13   a   1  and  13   a   2 . 
     FIG. 3A illustrates the construction of the fastening  13   a   1 , which is also the construction of fastening  13   a   2 , and is referred to herein as a fixed fastening. The fastening  13   a   1  comprises a sleeve  14  having an interior space D in which a screw  15  is mounted. The interior space D comprises a wider recess D 1  and an end bore D 2  (having a diameter smaller than the diameter of the wider recess D 1 ) and an inner threading N 1  on the end bore D 2 . The screw  15  is brought into engagement with inner threading N 1  by means of an outer threading N 2  of an extension or spindle part  15   a  of the screw  15 . In addition to the spindle part  15   a , the screw  15  also comprises a wider backup or head part  15   b  having a curved outer face  15   b   1 . On the face of the backup part  15   b , there is a groove U into which a seal ring U 1  has been fitted. The sleeve  14  comprises an edge widening  14   a  at the mouth of the space D. When the inner tube  11  is arranged in the space O inside the roll  10 , the fastenings  13   a   1 ,  13   a   2  on the inner tube  11  are placed in a certain position by rotating the screw  15  into a certain position in relation to the sleeve  14  so that a suitable degree of projection over the outer face  11   a   1  of the inner tube  11  is obtained for the head part  15   b  of the screw  15  from the space D 1  in the sleeve  14 . It is only after this is done that the tube  11  is locked in the interior of the roll  10  by using the third fastening  13   a   3  for the locking so that when the third fastening  13   a   3  is released from the pressure of hydraulic fluid, it presses the head of a released spindle against the inner face  10   a   1  of the roll  10  by means of the spring force of its springs (discussed below with reference to FIG.  3 B). 
     FIG. 3B illustrates the construction of the third fastening  13   a   3 . It is a so-called freely displaceable fastening in which the spindle part  16  of the fastening can be displaced by means of the pressure of a medium in the radial direction via remote control, i.e., from a location other than that at which the fastening  13   a   3  is situated. The fastening  13   a   3  comprises a sleeve  14  and an edge portion  14   a  in the vicinity of the inlet opening of its interior space D 1 . Thus, the sleeve  14  comprises an interior first space D 1  and, at its end, a second interior space D 2  having a smaller diameter than first space D 1  and between which spaces, an inside shoulder i remains. The spindle part  16  comprises a rod  16   a  and a head part  16   b  which is connected with the rod  16   a  and operates as a backup part and is coupled with the inner face  10   a   1  of the roll mantle  10   a  of the roll  10 . An intermediate or backup disk  17  is situated on the shoulder i and is locked by means of a cotter ring  18  so that it is stationary. The intermediate disk  17  comprises a central opening B through which the rod  16   a  of the spindle part  16  is passed freely. A seal  20   a  is arranged in the opening B in the intermediate disk  17  between the intermediate disk  17  and the rod  16   a  of the spindle part  16 . A seal  20   b  is placed between the intermediate disk  17  and the inner face of the sleeve  14 . 
     The head part  16   b  of the spindle part  16  is provided with a groove U, in which there is a seal ring U 1 . The rod  16   a  of the spindle part  16  is provided with a threading N 2  at its end, which threading N 2  is brought into engagement with the threading N 3  on an inner, central bore  21   a  in a piston part  21 . The end of the central bore  21   a  in the piston part is provided with an end disk  21   b . A cotter  22  which prevents rotation is arranged in engagement with the piston part  21  and to be guided freely in an end hole T in a portion of the space D 2 . The pressure fluid can be passed through a pipe  40  (see FIG. 1) into and from duct  41  in the sleeve  14  and further into and from the space D 2  between the piston part  21  and the intermediate disk  17 . In this manner, when the pressure fluid is passed into the space D 2 , a force acts upon the piston part  21  of the spindle part  16  and the spindle part  16  is pressed and moved in the direction S 1  against the spring force of the spring disks  22   a   1 ,  22   a   2  in the spring unit  22 . In this manner, the fastening  13   a   3  can also be installed freely into the interior of the roll  10  since it will not engage the inner surface of the roll mantle  10   a . Once the inner tube  11  is in its desired position, the effect of the pressurized fluid is discharged from the space D 2  and the springs  22   a   1 ,  22   a   2 , . . . in the spring unit  22  press with a force between the backup disk  17  and the head part  16   b  of the spindle part  16  so that the spindle part  16  and its head part  16   b  are displaced in the direction S 2 . As such, the curved backup face  16   b   1  of the head part  16   b  is urged against the inner face  10   a , of the roll mantle  10   a   1  of the roll  10 . 
     When the inner tube  11  is installed into the interior O of the roll  10 , first the fastenings  13   a   1 ,  13   a   2  provided on the tube  11  in each fastening plane T 1 , T 2 , . . . are installed so that their screws  15  have been rotated and locked, for example, by means of a locking glue in the threading of the sleeve  14  in a certain position. Thereafter, when the tube  11  is in a precise position in the space O in the interior of the roll mantle  10   a , the fastening  13   a   3  is made free from the pressure of the hydraulic fluid (i.e., the hydraulic fluid is removed from interior space D 2 ), and the springs in the spring unit  22  of the fastening  13   a   1  are thereby allowed to act with a force so that the head part  16   b  of the spindle part  16  of the fastening  13   a   3  is pressed by the spring force of the springs  22   a   1 ,  22   a   2 , . . . against the inner mantle face  10   a   1  of the roll mantle  10   a  of the roll  10 . 
     A pipe/hose  40  (FIG. 1) can be connected to the fluid duct  41  of the fastening  13   a   3 . Pipe/hose  40  can be passed from the end of the inner tube  11  on the outer face of the inner tube  11  to the fastening  13   a   3 . In this manner, the operation of the fastening  13   a   3  can be remote-controlled from the end of the roll  10  and the inner tube  11 . The pressure fluid is passed from an actuator, for example from an actuator of a reversing cylinder, to the pipe  40  and further to the fastening  13   a   3 . 
     By means of the present invention, the arrangement of the tubes one inside the other becomes clearly easier, as compared with prior art procedures. The mode of fastening also permits a larger play in respect of the measures of the outer and the inner tubes. Thus, inner tubes with equal diameter can be arranged in outer tubes with different diameters. Roll-specific tailoring is no longer needed, but inner tubes of standard diameter can be used. In this way, quicker installation and shorter delivery terms can be achieved. 
     The examples provided above are not meant to be, exclusive. Many other variations of the present invention would be obvious to those skilled in the art, and are contemplated to be within the scope of the appended claims.