Patent Publication Number: US-8523747-B2

Title: Hollow roller which can be heated with steam

Description:
FIELD OF THE INVENTION 
     The invention relates to a hollow roller, which can be heated with steam, which has a roller shell with an inner wall, two end walls, a centre longitudinal axis and an interior, which is rotatably mounted, which has a steam supply channel opening into the interior coaxially to the centre longitudinal axis and which has a siphon pipe which opens into the interior coaxially to the centre longitudinal axis, with a suction opening located adjacent to the inner wall. 
     BACKGROUND OF THE INVENTION 
     A hollow roller which can be heated with steam in this way is used, for example, in the production of corrugated board as a so-called fluted roller, as known from U.S. Pat. No. 6,092,579. Furthermore, hollow rollers of this type, which can be heated with steam, are used as so-called preheating rollers in corrugated board systems in order to preheat paper webs. Further areas of use are to be found in other technical areas; hollow rollers of this type are regularly used to warm or heat materials guided over them in webs. In this case, on the one hand, steam, generally saturated steam or superheated steam is blasted into the inner hollow roller. It gives off its heat via the inner wall of the hollow roller to the shell thereof, whereupon the water vapour condenses. The condensate collects because of the gravitational force and the centrifugal force of the rotating hollow roller on the inner wall thereof. This condensate layer acts in an insulating manner and therefore disturbs the heat transfer from the steam onto the roller. To remove the condensate, a siphon pipe is used, the suction opening of which is located close to the inner wall of the hollow roller. The spacing of the suction opening of the siphon pipe from the inner wall of the hollow roller is decisive for the residual quantity of condensate located in the interior of the hollow roller. Moreover, when a siphon pipe rests on the inner wall of the roller shell, the suction opening may cut in, so the siphon pipe rests tightly on the inner wall with the consequence that condensate can no longer be removed by suction. 
     In a hollow roller of this type, which can be heated with steam, known from EP 0 922 921 B1, the siphon pipe consists of an outer rigid support pipe and a flexible insert pipe displaceably mounted therein, so the spacing of the suction opening from the inner wall of the hollow roller can be adjusted. It has been shown in practice that it is only possible to adjust the spacing of the suction opening from the inner wall of the hollow roller when the hollow roller is stationary, in other words in operating breaks. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to develop a hollow roller, which can be heated with steam, of the generic type in such a way that an exact adjustment of the spacing between the suction opening and inner wall of the hollow roller is also possible during operation of the hollow roller. 
     This object is achieved according to the invention by the siphon pipe being formed rigidly and being held in a rotary feed-through, which is pivotable relative to the centre longitudinal axis about a pivot angle α in such a way that the spacing b of the suction opening from the inner wall is adjustable. As the adjustment of the spacing between the inner wall of the hollow roller and the suction opening of the siphon pipe is carried out by a pivoting of the rotary feed-through located outside the hollow roller and not rotating therewith, an adjustment of this type is also easily possible during the often high-speed operation of a hollow roller of this type. Readjustments during operation are also possible without a production system, in which the heatable hollow roller is located, having to be stopped. The siphon pipe resting on the hollow roller and therefore cutting in can thereby be avoided. The adjustment of the spacing of the suction opening from the inner wall may take place during operation in such a way that the siphon pipe is placed with its suction opening against the inner wall of the hollow roller. This can be detected acoustically or by measuring the vibration. The rotary feed-through is then adjusted about a predetermined angle, whereby the height of the gap between the suction opening and inner wall is fixed precisely. For this purpose, a corresponding display may be attached to the rotary feed-through. 
     The end wall adjacent to the rotary feed-through being provided with a hollow bearing journal, which is rotatably connected to a housing of the rotary feed-through so as to be pivotable about the pivot angle α in a steam-tight manner, the rotary feed-through having a steam supply connecting piece, which passes into the steam supply channel formed as a ring channel surrounding the siphon pipe, and the rotary feed-through being mounted on pivot bearings, depict advantageous configurations of the rotary feed-through. 
     A pivoting adjusting device being provided for the pivoting adjustment of the rotary feed-through with the siphon pipe, wherein the pivot bearing is arranged in a fixed manner, wherein the pivoting adjusting device is actuatable manually, wherein the pivoting adjusting device has adjusting screws for pivoting adjustment and wherein wherein the pivoting adjusting device is actuatable by a motor, depict various advantageous configurations of a pivoting adjusting device for the rotary feed-through. 
     The rotary feed-through with the siphon pipe being adjustable about the centre longitudinal axis about a rotation angle β, the rotary feed-through being mounted on a ring disc, which is rotatably and fixably supported, and the pivot bearings being attached to the ring disc, allow the suction opening to also be able to be pivoted and fixed in the peripheral direction, specifically in the rotational direction of the hollow roller, which, with regard to the high peripheral speeds of hollow rollers of this type in corresponding systems, has the advantage that condensate, because of being entrained on the inner wall of the hollow roller, is not removed by suction on the lowest roller base but further up. 
     Further features, advantages and details of the invention emerge from the following description of embodiments with the aid of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a vertical longitudinal section through a hollow roller according to the invention in an operating position with a suction opening of the siphon pipe located on the inner wall of the hollow roller, 
         FIG. 2  shows the hollow roller according to  FIG. 1  with the siphon pipe pivoted to a maximum height, 
         FIG. 3  shows a plan view of the hollow roller according to  FIGS. 1 and 2  in accordance with the viewing arrow III in  FIGS. 1 ,  2  and  4 , 
         FIG. 4  shows a side longitudinal view of the hollow roller according to  FIGS. 1 to 3  in accordance with the viewing arrow IV in  FIG. 3 , 
         FIG. 5  shows a hollow roller in accordance with the view in  FIG. 4  with a pivoting adjusting device which is changed compared to  FIGS. 1 to 4 , 
         FIG. 6  shows a modified embodiment of the hollow roller in a view according to  FIG. 1  with a rotary adjusting device, 
         FIG. 7  shows the hollow roller according to  FIG. 6  in a view according to  FIG. 4 , 
         FIG. 8  shows an end view of the hollow roller according to  FIGS. 6 and 7  in accordance with the viewing arrow VIII in  FIGS. 6 and 7  with a non-rotated siphon pipe, and 
         FIG. 9  shows a view in accordance with  FIG. 8  with a siphon pipe rotated in the rotational direction of the hollow roller. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The heatable hollow roller  1  shown in the drawings has a substantially cylindrical roller shell  2 , which is closed off in a steam-tight manner by two end walls  3  and  4 . Attached to the two end walls  3 ,  4  concentrically to the centre longitudinal axis  5  of the hollow roller  1  are bearing journals  6 ,  7 , which are mounted with roller bearings  8 ,  9  in bearing blocks  10 ,  11 . The hollow roller  1  is thus rotatably mounted. Hollow rollers of this type can generally be rotatably driven. A rotary drive of this type, not shown in the drawings, can take place by means of the bearing journal  6  shown on the left in the drawings. 
     The bearing journal  7  shown on the right in the drawings is hollow. Water vapour coming from a water vapour source, not shown, in accordance with the flow direction arrow  12 , is introduced into the hollow roller  1  through said bearing journal, so the roller shell  2  is heated. The water vapour condenses owing to this heating process and the heat output of the steam associated with it. The condensate is removed by suction from the lower region of the interior  13  of the hollow roller  1  by means of a so-called siphon pipe  14 , the suction direction being indicated by the flow direction arrow  15 . A negative pressure source, not shown, is connected to the siphon pipe  14 . 
     The water vapour supply and the condensate removal by suction take place by means of a so-called rotary feed-through  16 . This has a non-rotatable housing  17 , which is arranged substantially concentrically to the axis  5  and carries on its outer base  18 , the siphon pipe  14  rigidly connected to it. A vapour supply connecting piece  19  opens into the housing  17 . 
     The housing  17  of the rotary feed-through  16  is rotatably connected by means of a universal ball joint bearing  20 , and pivotably connected relative to the axis  5 , to the bearing journal  7 . The bearing  20  has a cylindrical inner wall  21 , so, on the one hand, the siphon pipe  14  is also free of the universal ball joint bearing  20  and furthermore, between the siphon pipe  14  and the housing  17  or the bearing journal  7 , a ring channel  22  is provided to supply the water vapour from the connecting piece  19  into the interior  13  of the hollow roller  1 . The universal ball joint bearing  20  may consist of a suitable plastics material, so that it simultaneously rests against the housing  17  consisting of metal in each case, on the one hand, and the bearing journal  7  on the other hand, so a steam seal to the outside is formed. However, other suitable seals can also obviously be provided. 
     In the operating position according to  FIG. 1 , the main longitudinal axis  23  of the siphon pipe  14  runs aligned with the centre longitudinal axis  5  of the hollow roller  1 . In this position of the siphon pipe  14 , its inner lower suction opening  24  has a minimum spacing a from the inner wall  25  of the hollow roller  1 . In the position of the siphon pipe  14  shown in  FIG. 2 , its main longitudinal axis  23  is pivoted about a pivot angle α relative to the centre longitudinal axis  5 , so the suction opening  24  has a larger spacing b from the inner wall  25 . This angle α may be up to 5°. The angle will generally be α≦2°. 
     A pivoting adjusting device to be actuated manually for the siphon pipe  14  emerges from  FIGS. 3 and 4 . In the bearing block  11  mounted on the hollow bearing journal  7 , in a horizontal plane, in which the centre longitudinal axis  5  is also located, bearing rods  26 ,  27  are screwed on either side of the bearing journal  7  and the housing  17 . The housing  17  of the rotary feed-through  16  is pivotably mounted by means of spherical pivot bearings  28  on these bearing rods  26 ,  27  so that the pivot movements described above with regard to  FIGS. 1 and 2  can be carried out. The two spherical pivot bearings  28  have a common horizontal pivot axis  29 , which runs aligned with the centre pivot axis  30  of the universal ball joint bearing  20 . 
     The pivoting adjustment and fixing of the rotary feed-through  16  with the siphon pipe  14  takes place in the embodiment according to  FIGS. 1 to 4  by means of two pairs of adjusting screws  31 ,  32  which are mounted in corresponding laterally projecting abutments  33 ,  34  and rest against the bearing rods  26  and  27 . By corresponding unscrewing of the upper adjusting screws  31  out of the corresponding upper abutments  33  and corresponding screwing of the respective lower adjusting screw  32  into the corresponding lower abutment  35 , the housing  17  of the rotary feed-through  16  is pivoted out of the position shown in  FIG. 1  into the position shown in  FIG. 2  and fixed there. This position is secured by counternuts  35 . 
     In the modified embodiment according to  FIG. 5 , a motor adjustment and fixing of the rotary feed-through  16  is possible. In this pivoting adjusting device, the bearing rods  26 ′,  27 ′ only have the spherical pivot bearings  28 . Instead of the adjusting screws  31 ,  32 , a linear drive  36  is provided in the form of a hydraulically or pneumatically drivable piston-cylinder drive, in which one lower end of the cylinder  37  is pivotably articulated to a fixed bearing  38 , while the piston rod  39  is articulated in the lower region of the housing  17  by means of a bearing  40 . By correspondingly loading the cylinder  37  with pressure fluid, the piston rod  39  is adjusted relative to the cylinder  37 , whereby the housing  17  of the rotary feed-through  16  is in turn adjusted in the manner described. The housing  17  is simultaneously fixed in this desired position by hydraulic locking. 
     The embodiment according to  FIGS. 6 to 9  differs from that according to  FIGS. 1 to 4  in that not only can the gap  41  between the suction opening  24  of the siphon pipe  14  and the inner wall  25  of the hollow roller  1  be adjusted, but the siphon pipe  14  can also be pivoted by a rotary adjusting device about its main longitudinal axis  23  so the opening  24  is not located in the vertical longitudinal centre plane  42  of the hollow roller  1 , as in the embodiment according to  FIGS. 1 to 4  or in the position according to  FIG. 8 , but in a longitudinal centre plane  43  inclined with respect to this about a rotation angle β, according to  FIG. 9 . In order to make this possible, configured on the bearing block  11 ′ is a ring bearing  44 , on which a ring disc  45  is rotatably mounted. The ring disc  45 —as can be seen from  FIGS. 6 ,  8  and  9 —is held by means of two screws  46  arranged in the vertical longitudinal centre plane  42  on the bearing block  11 ′. The screws  46  pass through slots  47  extending in the peripheral direction of the ring disc  45  so that—in accordance with the length of the slots  47 —the ring disc  45  can be adjusted about the angle β in the peripheral direction, which corresponds to the angle between the planes  42  and  43 . The bearing rods  26 ″ and  27 ″ are in this case fastened to the ring disc  45 . Otherwise, the structure is as described in  FIGS. 1 to 4 . 
     Owing to the adjustment possibility of the ring disc  45 , the housing  17  of the rotary feed-through  16  with the siphon pipe  14  can be pivoted about its main longitudinal axis  23 , so the opening  24  can be adjusted in the rotational direction  48  of the hollow roller  1 . As a result—in particular with hollow rollers  1  driven at high speed—it can be taken into account that the condensate mentioned is entrained in the rotational direction  48 . An adjustment of the spacing b of the suction opening  24  from the inner wall  25  of the hollow roller  1 , in other words an adjustment of the width of the gap  41 , also takes place here by means of the two pairs of adjusting screws  31 ,  32 .