Patent Publication Number: US-10330119-B2

Title: Method for the positioning of a cover disk of a pump and pump

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to EP Application No. 14197910.4, filed Dec. 15, 2014, the contents of which is hereby incorporated herein by reference. 
     BACKGROUND 
     Field of the Invention 
     The invention relates to a method for the positioning of a cover disk of a pump  3 . 
     Background Information 
     With regard to pumps having a so-called open impeller, i.e., having an impeller with only one cover disk, the so-called inner cover disk, a second cover disk, the so-called outer cover disk, has to be positioned with respect to the impeller and fastened to a pump housing on the assembly of the pump. A conveying passage of the pump arises due to the arrangement of the outer cover disk, whereby a conveying or pumping of the conveying medium is made possible. In this respect, the cover disk should be positioned at a specific spacing from the pump wheel, wherein it is in particular important that a uniform spacing is set via the pump wheel. The setting of a uniform spacing is in particular difficult because the positioning takes place by means of a plurality of adjustment bolts whose settings have to be coordinated with one another. The positioning of the cover disk has previously been carried out by service technicians without special auxiliary means, which has in part resulted in positionings of the cover disk which are not ideal and not reproducible. 
     SUMMARY 
     In contrast to this, it is in particular the object of the invention to put forward a method for the positioning of a cover disk of a pump which enables an assembly of a pump having a particularly high degree of efficiency. It is furthermore in particular the object of the invention to put forward a pump having an open impeller, with the pump having a particularly high degree of efficiency. In accordance with the invention, this object is satisfied by a method having the features disclosed herein 
     Having regard to the method in accordance with the invention for the positioning of a cover disk with respect to an open impeller of a pump arranged in a pump housing, with the pump in particular being a rotary pump, the cover disk and the pump housing are positioned with respect to one another first step, such that the cover disk comes into contact with the impeller and such that a desired spacing only has to be set in an axial direction between the cover disk and the impeller for reaching an end position of the cover disk. The axial direction is in this connection being understood as the direction which is fixed by the axis of rotation of the pump wheel and “comes into contact” is understood such that the cover disk can no longer be displaced in the axial direction further toward the impeller at any position. The cover disk is in this way arranged in such a way with respect to the pump housing that it only has to be positioned in the axial direction. 
     In a second step, a first adjustment bolt is screwed into a first threaded bore of the cover disk in particular designed as a through-hole until a bolt end of the first adjustment bolt comes into contact with a contact surface of the pump housing. The first adjustment bolt is in this respect only screwed in so far such that the cover disk continues to contact the impeller and does not yet lift off. In this respect, the turning in of the adjustment bolt in particular takes place manually, this means without the use of a tool, for example in the form of a wrench. 
     In a third step, an identifier which characterizes a position of a first marking in particular at a periphery of the first adjustment bolt is applied at the cover disk or at the pump housing. The identifier is in particular effected by means of a pen. However, it is also possible for the identifier to be carved in or to be effected by means of a label. 
     In a fourth step, the first adjustment bolt is turned in further until a second marking in particular at the periphery of the first adjustment bolt reaches the identifier at the cover disk or at the pump housing such that the desired spacing is set between the cover disk and the impeller. 
     The second to fourth steps are carried out for at least a second adjustment bolt and in particular also for a third and for a fourth adjustment bolt or for all other adjustment bolts. More than four adjustment bolts can also be used. The adjustment bolts in this respect have like threads, in particular like thread pitches. Furthermore, the first and second markings are arranged in a similar manner with respect to one another at the adjustment bolts, with a relative angular position of the two markings in particular being identical. All the adjustment bolts are in this way turned by the same angle in the fourth step, which, with an identical thread pitch, results in an identical displacement of the cover disk in the axial direction with respect to the pump housing at each adjustment bolt. A preferable spacing between the cover disk and the impeller can be fixed by a suitable selection of the thread pitch and of the arrangement of the first and second markings at the adjustment bolts. Only identical adjustment bolts are in particular used. 
     The method in accordance with the invention is in particular carried out such that the first step is carried out and subsequently the second step is carried out for all of the adjustment bolts, then the third step is carried out for all of the adjustment bolts and then the fourth step is carried out for all of the adjustment bolts. Mixed forms are, however, also possible. It is likewise possible that one or all of the adjustment bolts are already screwed a little into the threaded bores of the cover disk prior to the carrying out of the first step. 
     The adjustment bolts are in this respect in particular designed and have a corresponding pitch such that, in the fourth step, the adjustment bolts have to be screwed in between 20° and 90°, in particular by 70°, for setting the desired spacing. The second marking at the adjustment bolts is in this way arranged offset to the first marking between 20° and 90°, in particular by 70°, with respect to the direction of turning in. 
     In an embodiment of the invention, the first and second markings are made as notches at the periphery of the adjustment bolts and have different shapes, with a notch in particular being able to have a V shape, a rectangular shape or a rounded shape. The notches in particular extend in the axial direction over the complete outer thread of the adjustment bolts. The two markings can in this way be distinguished particularly easily, whereby a secure and reproducible positioning of the cover disk is enabled. 
     The two markings can be distinguished particularly easily when they have different colors. 
     In an embodiment of the invention, the adjustment bolts have a third and a fourth marking, with the third marking being made in a manner corresponding to the first marking and the fourth marking being made in a manner corresponding to the second marking and the arrangement or the angular offset of the fourth marking with respect to the third marking corresponding to the arrangement or to the angular offset of the second marking with respect to the first marking. It is in this way ensured that at least one first marking is always easily accessible and a simple positioning of the cover disk is possible in this way. 
     The markings do not necessarily have to be arranged at the periphery of the adjustment bolts. They could, for example, also be arranged at a bolt head of the adjustment bolts. 
     In an embodiment of the invention, the adjustment bolts are designed as sleeves in which fastening elements can be arranged, for example in the form of solid fastening bolts by means of which the cover disk is fastened to the pump housing in a fifth step. The fifth step is in this respect in particular only carried out then when the fourth step has been carried out for all of the adjustment bolts. A particularly simple and secure fastening of the cover disk at the pump housing is possible in this way. 
     In an embodiment of the invention, the desired spacing between the cover disk and the impeller amounts to between 0.1 and 0.3 mm, in particular to between 0.15 and 0.25 mm. A particularly high degree of efficiency of the pump is enabled in this way. 
     In an embodiment of the invention, the position of the adjustment bolts is secured at a reached desired spacing between the cover disk and the impeller, with the securing of the position of the adjustment bolts taking place by means of locking nuts. The locking nut is for this purpose tightened with respect to the side of the cover disk remote from the housing after the desired spacing has been reached. In this way, the position of the adjustment bolt is fixed, on the one hand, and any clearance which may be present in the connection between the cover disk and the adjustment bolt is eliminated, on the other hand. A particularly secure and exact setting and maintenance of the desired spacing is made possible in this way. 
     The object is also satisfied by a pump having a pump housing, having an open impeller arranged therein and having a cover disk for the impeller, wherein the cover disk has at least two threaded bores in which a respective adjustment bolt is arranged by which, starting from a contact of the cover disk at the impeller, a desired spacing between the cover disk and the impeller can be set, with bolt ends of the adjustment bolts only contacting contact surfaces of the pump housing on contact of the cover disk at the impeller and with the cover disk or the pump housing having identifiers at least during the setting of the desired spacing between the cover disk and the impeller, the identifiers characterizing a position of a first marking in particular at a periphery of the adjustment bolts on contact of the cover disk at the impeller and characterizing a position of a second marking in particular at the periphery of the adjustment bolts with a set desired spacing between the cover disk and the impeller, with the adjustment bolts having like threads and with the first and second markings being arranged in a similar manner with respect to one another at the adjustment bolts. 
     “At least during the setting of the desired spacing” is to be understood in this case such that the identifiers do not have to be present permanently at the cover disk or at the pump housing. The identifiers can be removed or can vanish during the use of the pump after the setting of the desired spacing and after the secure fastening of the cover disk to the pump housing. 
     Further advantages, features and details of the invention result with reference to the following description of embodiments and by means of the drawings in which elements which are the same or which have the same function are provided with identical reference numerals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in more detail hereinafter with reference to the drawings. 
         FIG. 1  is a rotary pump in a sectional representation; 
         FIG. 2  is a detail of  FIG. 1 ; and 
         FIG. 3  is an adjustment bolt with a part of a cover disk of a rotary pump in a plan view. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In accordance with  FIG. 1 , a pump  10  in the form of a rotary or centrifugal pump has a pump housing  11  in which an open impeller  12  is arranged. The impeller  12  can rotate about an axis of rotation, which is aligned along an axial direction  13 , and can be driven by a drive machine not shown, for example by an electric motor. A conveying medium, for example in the form of water, is supplied in the axial direction via an inlet  14  and is radially led off at elevated pressure via an outlet  15 . A so-called cover disk  16  is arranged at a side of the impeller  12  remote from the inlet  14  and is fastened to the pump housing  11 . The cover disk  16  has a predominantly ring-shaped basic shape with a total of four fastening eyelets  17   a ,  17   b  offset by 90°, of which two are shown in  FIG. 1 . The number of adjustment bolts is in this respect selected in dependence on the size of the pump  10  and on the pressure at the outlet  15 . More or fewer adjustment bolts can in this way also be used. An inner surface  18  of the cover disk  16  aligned in the direction of the impeller  12  is in this respect designed inclined such that it is adapted to the contour of the impeller  12 . The cover disk  16  forms a conveying passage  19  of the pump  10  together with the pump housing  11 . 
     A first fastening eyelet  17   a  of the cover disk  16 , which is shown enlarged in  FIG. 2 , has a first axially extending threaded bore  20  in the form of a through-hole having an inner thread not shown in detail. A first adjustment bolt  21  in the form of a sleeve having an outer thread not shown in detail is screwed into this threaded bore  20  such that a bolt end  22  of the adjustment bolt  21  contacts a contact surface  23  of the pump housing  11 . The threaded bore  20  of the fastening eyelet  17   a  is in this respect flush with a threaded bore  24  in the form of a blind hole in the pump housing  11 . A fastening bolt  25  projects through the adjustment bolt  21  and is screwed into the threaded bore  24  in the pump housing  11 . A fixing of the cover disk  16  at the pump housing  11  is realized by means of the adjustment bolt  25 . Furthermore, a locking nut  26  is arranged at the side of the cover disk  16  remote from the pump housing  11  at the adjustment bolt  21 , with the locking nut tensioning the adjustment bolt  21  toward the fastening eyelet  17   a  of the cover disk  16  via the outer thread of the adjustment bolt  21 . The design of the three other fastening eyelets and in particular of the used adjustment bolts, locking nuts and fastening bolts is identical. 
     In its end position, the cover disk  16  should be arranged at a fixed desired spacing from the pump wheel  12  of approximately between 0.1 and 0.3 mm, in particular between 0.15 and 0.25 mm. If the spacing is too small, a contact between the pump wheel  12  and the cover disk  16  may occur and in this way result in damage. If the spacing is too large or non-uniform, the degree of efficiency of the pump  10  is not ideal. 
     The desired spacing between the cover disk  16  and the pump wheel  12  has to be set on the assembly of the pump  10 . For this purpose, the cover disk  16  is first positioned with respect to the pump housing  11  in a first step such that the threaded bores  20  of the fastening eyelets  17   a ,  17   b  are flush with the threaded bores  24  of the pump housing  11  and such that the cover disk  16  furthermore contacts the impeller  12 . The impeller  12  could not rotate in this position of the cover disk  16  such that an axial displacement of the cover disk  16  is necessary. A suitable apparatus, not shown, can be used for the positioning of the cover disk  16 . 
     In a subsequent second step, the total of four adjustment bolts  21  are manually screwed in so far into the threaded bores  20  of the fastening eyelets  17   a ,  17   b  that the bolt ends  22  of the adjustment bolts  21  come into contact with the contact surfaces  23  of the pump housing  11 . The adjustment bolts  21  are in this respect only screwed in so far that the cover disk  16  continues to contact the impeller  12  and does not yet lift off. 
     In a subsequent third step, an identifier  27  which identifies a position of a first marking  28  at the periphery of the adjustment bolt  21  (see  FIG. 3 ) is applied at the fastening eyelet  17   a  of the cover disk  12  using a pen. The first marking  28  has an outwardly open V-shaped contour and is marked in red, with the marking in red also being able to be dispensed with. It extends in the axial direction over the total length of the outer thread of the adjustment bolt  21 . This is repeated for the three other adjustment bolts. 
     In a subsequent fourth step, the adjustment bolt  21  is screwed in further using a wrench until a second marking  29  at the periphery of the adjustment bolt  21  reaches the identifier  27  at the fastening eyelet  17   a  of the cover disk  12  (not shown). The desired spacing between the cover disk  16  and the impeller  12  is in this way set at this fastening eyelet  17   a . The second marking  29  has an outwardly open rectangular contour and is marked in green. It extends in the axial direction over the total length of the outer thread of the adjustment bolt  21 . This is repeated for the three other adjustment bolts. 
     The second marking  29  is in this respect arranged offset to the first marking  28  by 70° with respect to the direction of screwing in  30 . The second marking can also be offset with respect to the first marking to a lesser or greater degree. The adjustment bolt  21  furthermore has a third marking  31  disposed diametrically opposite the first marking  28  and has a fourth marking  32  disposed diametrically opposite the second marking  29 . The third marking  31  has an identical V-shaped design and an identical color identifier as the first marking  28 . The fourth marking  32  has an identical rectangular design and an identical color identifier as the second marking  29 . In this way, the identifier at the cover disk  16  can also be effected at the third marking  31  in the third step and, in the fourth step, the adjustment bolt  21  can subsequently be screwed in until the fourth marking is reached. The set spacing between the cover disk  16  and the pump wheel  12  is then the same as in the procedure described above. 
     The locking nuts  26  are subsequently screwed onto the adjustment bolts  21  and tensioned with respect to the fastening eyelets  17   a ,  17   b . In a fifth step, the fastening bolts  24  are finally screwed into the threaded bores  24  of the pump housing  11  such that the adjustment bolts  21  are pressed against the pump housing  11 . The cover disk  16  is in this way connected to the pump housing  11  and the same desired spacing between the cover disk  16  and the pump wheel  12  is set and maintained everywhere by the adjustment bolts  21 . 
     The pump  10  has the identifier  27  at least during the setting of the desired spacing between the cover disk  16  and the impeller  12 . The identifier  27  can be removed after the cover disk  16  has been fixedly connected to the pump housing  11 .