Abstract:
Discloses apparatus for use with a modular fluid pump assembly, particularly pumps used to pump fluids containing entrained contaminants such as grit. The apparatus includes a pair of removable end plates attachable to a modular pump housing. A bearing assembly is detachably mountable on the exterior of the and plate and provides a cavity to receive a pump shaft fitted with a shaft seal and shaft bearing. A grit collar to surround the pump shaft is mountable on the interior side of the end plate. Replacement of the pump seals or bearings can be effected by removing the bearing assembly. More extensive maintenance, such, as replacement of the grit collar or pump gear or shaft, can be effected by removing the end plates.

Description:
This invention relates to pump assemblies and to apparatus for modular liquid pump assemblies and more particularly to pump assemblies for pumps adapted for pumping contaminated liquids. 
     BACKGROUND OF THE INVENTION 
     Fluid pumps adapted for use in pumping liquids and fluids, such as oils and distillates produced from oil wells, frequently contain entrained contaminating materials such as sand, grit and the like. The pumping of such fluids results in the entrained gritty materials that are found in the fluid to come into contact with the pump elements, in particular, the pump surface elements as well as the pump bearings and seals. Where large volumes of fluid are pumped or a pump is used frequently, such as to empty a holding tank near the well site, the pump mechanical elements are exposed routinely to the entrained gritty materials. Consequently, pumps in service for such tasks have a tendency to wear prematurely and fail after a short period of use, such as after a few months or less than one year. 
     In the past, modular pump assemblies have been proposed to provide double fluid seals such as that disclosed by Korenblit in Canadian patent 2,021,157 which provides tandem mounted face seals each having a different construction, that is a flexible seal and a non-flexible seal to improve seal performance. Another seal arrangement is shown by Ernens in published Canadian patent application 2,226,693. The seal arrangement of Ernens situates the seals between the pump rotor and bearings. A high pressure hydraulic system and pump including high pressure seals at both ends of the pump driven shaft to reduce or eliminate forces that might tend to increase friction and wear is disclosed in published Canadian patent application 2,246,100 by Tieben. 
     However, to improve the serviceability of pumps and the increase the operating life of pumps put to uses involving pumping fluids containing grit materials, such as pumping field holding tanks of oil wells and the like, other pump assemblies are needed than have heretofore been provided. It is an object of this invention to provide a apparatus for modular pumps that provides for ease of maintenance and parts replacement of pump parts to decrease the cost of pump maintenance and to improve the life expectancy of the pump assembly. 
     SUMMARY OF THE INVENTION 
     In one of its aspects, the invention provides apparatus for a modular pump assembly that includes easy accessibility to replaceable seals and bearings with modular end plate assemblies to allow servicing with a minimum of parts required to be replaced. 
     The pump is provided with a housing including multi-part removable end plates that facilitate access to pump seals and bearings as well as entry into the pump cavities to replace the pump elements. The multi-part removable end plates include removable bearing assemblies that permit the pump bearings to be accessed to replaced or the pump seals to be replaced without requiring disassembly of the entire pump housing and pump cavity assembly. 
     In one of its aspects, the invention provides modular pump apparatus for a modular fluid pump including a pair of end plates adapted to be removably sealingly attachable to a modular pump housing, each end-plate forming at least one shaft passage to receive a pump shaft therethrough. Each shaft passage in the endplate has a bearing mount provided on the outer side of the endplate for attachment of at least one bearing assembly, and a grit collar mount on the inner side of the endplate. The modular pump apparatus further includes at least one bearing assembly dimensioned to fit on to the bearing mount. The bearing mount forms a cavity to receive a pump shaft fitted with a shaft seal and a shaft bearing and means to releasably secure the bearing assembly to the endplate. A grit collar, adapted to receive a pump shaft therethrough, is mountable in the grit collar mount of the endplate. 
     Other aspects of the invention will appear from the following description and appended claims. The invention will now be explained with reference to the accompanying drawings in which like reference numerals have been used throughout the various figures of the drawings: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of the preferred embodiment of the modular pump assembly, but not including the pump gears and pump cavity housing for clarity. 
     FIG. 2 is an elevation view of the pump assembly drive shaft apparatus of FIG.  1 . 
     FIG. 3 is an elevation view of the pump assembly idler shaft assembly of the apparatus of FIG.  1 . 
     FIG. 4 is an exploded view of the drive shaft assembly of the pump assembly of FIG.  2 . 
     FIG. 5 is an exploded view of the idler shaft assembly of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a side elevation view of the preferred embodiment of the modular pump assembly. The drive elements of the modular pump, such as a helical two gear pump, are shown in FIG. 1, but, for clarity the pump drive gears  17  and only a portion of the pump housing are shown in dotted outline form in the figure. A drive shaft  12  provides rotating support for a first gear  17  and the idler shaft  14  provides rotating support for a second pump gear  17  spacedly disposed from the first. Each of these gears  17  is disposed within the pump housing  15  and between side endplate  18  and  20 . Sealingly attached to the pump housing  15  to seal the pump cavity formed in the pump housing in the pump gears  17  operate to pump the fluid to be pumped. Fluids to be pumped are captured between the teeth of the gears  17  that are mounted on drive shaft  12  and counter-rotating idler shaft  14  to cause the fluid to be pumped through the cavity formed in the pump housing  15  of the pump. Drive shaft  12  includes a keyway slot  16  to provide a rotational coupling to the driven gear  17  of the pump. Sealingly disposed on either side of the pump cavity on the exterior of the pump housing  15  are end plates  18  and  20 . Preferably, both end plates  18  and  20  are the same configuration to reduce parts overhead. However, it will be understood by those skilled in the art that the drive side end plate  18  can be dimensioned to meet the requirements for mounting the end plate on the housing and can be of a different shape and dimension than idler side end plate  20  if so required by the design and construction of the pump housing. As shown most clearly in FIGS. 2 and 3, each end plate  10  and  20  has a number of peripherally disposed fastener mounts  19  which are used to attach the end plates  18  and  20  to the pump housing  15 . Fastener mounts  19  are preferably holes though which bolts can pass to secure the end plates  18  and  20  to the pump housing  15 . 
     In the preferred embodiment depicted in FIGS. 1,  2  and  3 , end plates  18  and  20  share a common design. Affixed to end plate  20  are cups forming bearing assemblies  22 . Preferably, bearing assemblies  22  are removably affixed to the end plate by means of bolts  24 . Provided at the distal end of bearing assembly  22  is an end bolt, either  26  or  28 . End bolt  28  is interchangeable with end bolt  26  and end bolt  28  includes a mount for a grease zerk  30 , while end bolt  26  has no such grease zerk  30  mount. Grease zerk  30  is coupled to a pressure greaser to apply grease to the bearings of the pump. Shown in dotted outline form in FIG. 1 are grit collars  32  which are dimensioned to slidingly receive the respective drive shafts  12  or  14  therethrough. Preferably grit collar  32  is constructed from bronze and disposed on a mount provided in end plates  18  and  20 . Preferably grit collar  32  is frictionally engaged in a mounting recess provided in end plates  18  and  20 . Grit collar  32  prevents larger debris entrained in the fluid being pumped, such as sand, grit and the like, from coming into contact with the seals and bearings held within the bearing cup bearing assembly  22 . Drive bearing assembly  34  for the drive shaft preferably includes a grease zerk  30  as well to permit grease to be applied to the bearing of the driven shaft of the pump. In the preferred embodiment, surrounding bearing assembly  22  is a hold down ring  36 . Hold down ring  36  is dimensioned to slide over the exterior of bearing assembly  22  or  34  but interferingly fit with or against protrusion  38  circumferentially extending around bearing assembly  22  and driver bearing assembly  34 . In this way, bearing assembly  22  or drive bearing assembly cup  34  can be releasably retained against end plates  18  or  20  when the hold down ring  36  is bolted to the respective end plate with bolts  24 . When service of the pump seals or bearings is required, to replace them for example, all that is needed to gain access to the bearings or seals is to remove the bearing assembly  22  from the end plate  18  or  20  by undoing bolts  24 . It is not necessary to undo or remove the end plates  18  or  20  themselves from the pump assembly for this servicing. 
     Preferably grit collar  32  is constructed with a shoulder  33  to provide a thrust surface  35  elevated or projecting upwardly from the surrounding surface  37  of the interior facing side of end plates  18  and  20 . This thrust surface provides a lateral or axial stop for the rotating pump elements, such as the pump gears  17 , and the like. With such a thrust surface, the rotating pump elements will tend not to wear the end plates as quickly and grit collars  30  can the replaced as needed to increase the service life of endplates  18  and  20 . 
     Referring to FIG. 4, the drive shaft bearing assemblies are shown in exploded view for clarity of the modular component construction. The exploded view also shows the component rotational bearings and seals of the drive shaft assembly. Drive bearing assembly  34  has an exterior facing packing nut  40  that is retained within drive bearing assembly  34  by means of bolts  42 . Disposed within packing nut  40  is a bearing  44  that provides rotational support of drive shaft  12 , which extends therethrough when assembled as depicted in FIG.  1 . Preferably bearing  44  is a bronze bushing construction. Bearing  44  provides rotational support proximal to the external protruding end  46  of the drive shaft to facilitate mounting drive couplings, such as pulleys, sprockets or collars on the external protruding end  46  of the drive shaft to couple the pump to a source of rotational power such as a motor. A seal  48 , for example an o-ring seal, extends around drive shaft  12  and is adjacent to bearing  44 . The bearing  44  and seal  48  are retained within packing nut  40  by means of collar  50  which is preferably threaded onto the exposed end  52  of the packing nut  40 . Drive shaft  12  extends through end plate  18  and is sealed with respect to the interior of the pump cavity by means of a seal  54 . Seal  54  is retained in place on the interior side portion of end plate  18  using a seal holder  56 . 
     A rotational bearing  58  and thrust bearing  60  are mounted on drive shaft  12  to provide for drive shaft rotational support as well as axial support when the apparatus is in the assembled configuration shown in FIG.  1 . Axial or lateral movement of drive shaft  12  is limited by a lock collar  62  which is releasably affixed to drive shaft  12  using a lock nut  64 . Lock collar  62  is set at the desired axial or lateral position of drive shaft  12  with respect to end plate  18 . Provided on the interior side of end plate  18  is a grit collar  32  which is dimensioned to receive drive shaft  12  therethrough. The opposite end of drive shaft  12  passes through end plate  20  which has grit collar  32  mounted on the side surface thereof. On the exterior side of end plate  20  is bearing assembly  22  into which bearing  66  is received. Bearing  66  provides rotational support for drive shaft  12  and can be serviced or replaced by removing bearing assembly  22  from end plate  20 . Bearing assembly  22  is removed from end plate  20  by undoing bolts  24  that secure hold-down ring  36  to the end plate  20 . 
     Fluids from the pump cavity on the interior side of end plate  20 , where grit collar  32  is disposed, are kept from contact with bearing  66  by means of seal  68 . Preferably bearing  66  is a bronze bushing and seal  68  is an o-ring. To replace seal  68  or bearing  66 , or both, all that is required is to loosen bolts  24  and remove hold down ring  36  which will free the bearing assembly  22  from the end of drive shaft  12  permitting access to the bearing  66 , and seal  68  for replacement. End bolt  26  is threadingly received in the crown of bearing assembly  22  and may include a seal  70  where bolt  26  is not provided with a tapered pipe thread that will seal mechanically to bearing assembly  22 . If desired, end bolt  26  can be replaced by an end bolt  28  which is configured to receive a grease zerk  30 . A seal  70  is used when bolt  26  is not a pipe thread, but rather a standard thread. Standard thread is preferable to allow the thread hole to be advantageously used to mount a puller apparatus (not shown). 
     Referring to FIG. 5, the idler shaft assembly of FIG. 1 is shown in exploded view. The upper portion of FIG. 5 shows an alternative bearing configuration. The alternate bearing configuration includes a rotational bearing  58  and thrust bearing  60 . Idler shaft  14  is maintained in axial or lateral displacement with respect to end plate  18  by means of lock collar  62 . Once idler shaft  14  has been positioned with respect to end plate  18 , lock collar  62  is affixed to idler shaft  14  by manipulation of lock nut  64 . To keep the fluids from the pump cavity from reaching bearings  58  and  60 , a seal  54  is provided which is retained in place by means of seal holder  56 . Larger materials such as sand, grit and the like are kept away from seal  54  by means of grit collar  32  which is disposed on the opposite side of end plate  18  from bearing assembly  22 . Bearing assembly  22  is releasably secured to end plate  18  by means of bolts  24  interacting with hold down ring  36  to secure the bearing assembly  22  to end plate  18  and contain all of the elements  54 ,  56 ,  58 ,  60 ,  62  and  64  therein. To replace the seals, bearings or seal holder, all that is required is to remove the bearing assembly  22  from the end plate  18 . It is not necessary to remove end plate  18  from the pump housing  15 . Grease zerk end bolt  28  has a grease zerk  30  mounted therein. If grease zerk end bolt  28  does not have tapered pipe threading, then seal  70  can be used to maintain a sealed configuration of bolt  28  to bearing assembly  22 . Grease zerk  30  is used to supply grease to the bearing elements contained within bearing assembly  22 . The lower portion of FIG. 5 shows the bearing assembly  22  for the opposite end of idler shaft  14 . The apparatus and configuration of the bearing assembly on this end of the idler shaft is preferably the same as the configuration and assembly described with reference to the bearing assembly  22  of FIG. 4 also mounted on end plate  20 . 
     Now that the invention has been described, numerous modifications and substitutions with occur to those skilled in the art within the spirit and scope of the invention as defined in the claims appended hereto.