Abstract:
Some embodiments of the present invention provide a pump including a pump housing having an inlet adapted to fluidly couple with an inlet conduit, and an outlet adapted to fluidly couple with an outlet conduit. The pump also includes a pump shaft rotatably supported in the pump housing and a plurality of impellers coupled for rotation with the pump shaft. The pump further includes a motor removably coupled to the pump housing. The motor has an output shaft drivably coupled to the pump shaft. The pump also includes a spacer positioned between the plurality of impellers and the motor. The spacer includes at least one aperture to access and de-couple the output shaft and the pump shaft. The motor, spacer, pump shaft, and the plurality of impellers are removable from the pump housing as a single unit without disconnecting the inlet conduit and the outlet conduit from the pump housing.

Description:
FIELD OF THE INVENTION 
   This invention relates generally to pumps, and more particularly to readily serviceable pumps. 
   BACKGROUND OF THE INVENTION 
   Pumps are typically utilized in various applications to increase the pressure of fluid provided by a fluid source. Conventional pumps can include an inlet to connect to an inlet conduit providing fluid from the fluid source at an initial pressure, and an outlet to connect to an outlet conduit carrying pressurized fluid away from the pump. Servicing conventional pumps typically requires disconnecting the inlet and outlet conduits from the pumps and completely disassembling the pumps to gain access to the pumps&#39; internal components. As a result, the inlet and outlet conduits must be reconnected to the pumps after the pumps are serviced. Such a process often results in extended periods of downtime. Also, having to frequently disconnect and reconnect the inlet and outlet conduits and the pumps can increase the likelihood of leakage between the conduits and the pumps. 
   SUMMARY OF THE INVENTION 
   Some embodiments of the present invention provide a pump including a pump housing having an inlet adapted to fluidly couple with an inlet conduit, and an outlet adapted to fluidly couple with an outlet conduit. The pump also includes a pump shaft rotatably supported in the pump housing and a plurality of impellers coupled for rotation with the pump shaft. The plurality of impellers are operable to pressurize a fluid in the pump housing. The pump further includes a motor removably coupled to the pump housing. The motor has an output shaft drivably coupled to the pump shaft. The pump also includes a spacer positioned between the plurality of impellers and the motor. The spacer is coaxial with the output shaft and the pump shaft. The spacer includes at least one aperture located and sized to enable access the output shaft and the pump shaft to de-couple the output shaft and the pump shaft. The motor, spacer, pump shaft, and the plurality of impellers are removable from the pump housing as a single unit without disconnecting the inlet conduit and the outlet conduit from the pump housing. 
   Other embodiments of the present invention provide a pump including a pump housing having an inlet adapted to fluidly couple with an inlet conduit and an outlet adapted to fluidly couple with an outlet conduit, a pump shaft rotatably supported in the pump housing, and a plurality of impellers coupled for rotation with the pump shaft. The plurality of impellers are operable to pressurize a fluid in the pump housing. The pump also includes a motor coupled to the pump housing. The motor has an output shaft drivably coupled to the pump shaft. The pump further includes a seal cap positioned between the motor and the pump housing to at least partially seal against the pump housing. The seal cap includes an aperture dimensioned to receive one of the output shaft and the pump shaft. The pump also includes a seal assembly having a stationary seal coupled to the seal cap and coaxial with the aperture. The stationary seal has a stationary surface. The seal assembly also has a rotating seal coupled for rotation with the one of the output shaft and the pump shaft. The rotating seal has a rotating surface engageable with the stationary surface. The stationary surface and the rotating surface are axially spaced from an interior surface of the seal cap. 
   Some embodiments of the present invention provide a method of servicing a pump. The method includes providing a pump housing fixed to a support surface. The pump housing includes an inlet fluidly coupled with an inlet conduit and an outlet fluidly coupled with an outlet conduit. The method also includes providing a pump assembly in the pump housing and a motor drivably coupled to a portion of the pump assembly. The motor is coupled to the pump housing and spaced from a remaining portion of the pump assembly by a spacer. The method further includes de-coupling the motor from the pump housing and removing the motor and the pump assembly from the pump housing as a single unit while the inlet conduit remains fluidly coupled with the pump housing inlet, and the outlet conduit remains fluidly coupled with the pump housing outlet. The method also includes accessing an interface between the motor and the pump assembly through an aperture in the spacer to de-couple the motor and the pump assembly and separating the motor from the pump assembly. 
   Other embodiments of the present invention provide a pump including a pump housing having an inlet adapted to fluidly couple with an inlet conduit, and an outlet adapted to fluidly couple with an outlet conduit, and a pump assembly operable to pressurize a fluid in the pump housing. The pump assembly includes a pump shaft rotatably supported in the pump housing, at least one impeller coupled for rotation with the pump shaft, at least one suction cap positioned upstream of the at least one impeller, at least one diffuser positioned downstream of the at least one impeller, and a retainer coupled to the pump shaft downstream of the at least one diffuser. The pump also includes a motor removably coupled to the pump housing and having an output shaft drivably coupled to the pump shaft. The motor is removable from the pump housing with the pump assembly as a single unit. 
   Yet other embodiments of the present invention provide a method of servicing a pump. The method includes providing a pump housing coupled to a support surface. The pump housing includes an inlet fluidly coupled with an inlet conduit, and an outlet fluidly coupled with an outlet conduit. The method also includes providing a pump assembly in the pump housing. The pump assembly includes a pump shaft rotatably supported in the pump housing, at least one impeller coupled for rotation with the pump shaft, at least one suction cap positioned upstream of the at least one impeller, at least one diffuser positioned downstream of the at least one impeller, and a retainer coupled to the pump shaft downstream of the at least one diffuser. The method further includes providing a motor drivably coupled to the pump shaft, de-coupling the motor from the pump housing, and removing the motor and the pump assembly from the pump housing as a single unit. 
   Other features and aspects of the present invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, wherein like reference numerals indicate like parts: 
       FIG. 1  is an exploded perspective view of a pump of the present invention. 
       FIG. 2  is an assembled, partial cross-sectional view of the pump of  FIG. 1 , illustrating an inlet conduit and an outlet conduit fluidly coupled to the pump. 
       FIG. 3  is a partially-exploded perspective view of the pump of  FIG. 1 , illustrating a motor and a pump assembly being removed from a pump housing while maintaining the connections of the inlet conduit and the outlet conduit to the pump housing. 
       FIG. 4   a  is an enlarged, partially-exploded perspective view of the pump of  FIG. 1 , illustrating an output shaft of the motor being disconnected from a coupling joining the output shaft to a pump shaft. 
       FIG. 4   b  is an enlarged, partially-exploded perspective view of the pump of  FIG. 1 , illustrating the coupling disconnected from the output shaft. 
       FIG. 5  is an exploded perspective view of an alternative embodiment of the output shaft and the coupling of the pump of  FIG. 1 . 
       FIG. 6   a  is an enlarged, partial cross-sectional view through the pump of  FIG. 1 , illustrating a seal plate and a mechanical seal. 
       FIG. 6   b  is an enlarged view of the seal plate and mechanical seal of  FIG. 6   a.    
   

   Before any features of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including”, “having”, and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of letters to identify elements of a method or process is simply for identification and is not meant to indicate that the elements should be performed in a particular order. 
   DETAILED DESCRIPTION 
     FIGS. 1-6   b  illustrate a pump  10  constructed in accordance with some embodiments of the present invention. With reference to  FIGS. 1-3 , the pump  10  generally includes a pump housing  14 , a pump assembly  18  positioned in the pump housing  14 , and a motor  22  coupled to the pump housing  14  and drivably coupled to the pump assembly  18  along a central axis  26 . As shown in  FIG. 3 , the pump housing  14  generally includes an inlet portion  30  and an outlet or discharge portion  34 . The inlet portion  30  and the discharge portion  34  can be coupled using any of a number of different methods such as, for example, welding or brazing, using a threaded connection, using tie rods, and so forth. If threads or tie rods, for example, are utilized to couple the inlet portion  30  and the discharge portion  34 , an O-ring (not shown) or other seal (e.g., a square ring, quad ring, etc.) can be utilized to seal the inlet portion  30  to the discharge portion  34 . Alternatively, the discharge portion  34  can be integrally formed with the inlet portion  30 , such that the pump housing  14  is a one-piece construction. In the illustrated embodiment, the discharge portion  34  is shown as a two-piece construction that is joined together by a welding process, for example. Alternatively, the discharge portion  34  can be a one-piece construction. 
   The inlet portion  30  includes a base  36  for mounting the pump housing  14  to a support surface  40  (see  FIG. 6   a ). The base  36  includes a plurality of apertures  44  through which fasteners  48  (e.g., bolts, screws, etc.) can be passed to mount the pump housing  14  to the support surface  40 . Alternatively, the base  36  can include other mounting structure configured to mount to mating mounting structure fixed to the support surface  40 . 
   The inlet portion  30  also includes a flange  52  for mounting the motor  22  to the pump housing  14 . In the illustrated embodiment of  FIG. 1 , the flange  52  incorporates a square bolt pattern including four apertures  56 . The motor  22  includes a flange  60  incorporating a plurality of apertures  64  conforming to the same square bolt pattern, such that fasteners  68  (e.g., bolts) can be passed through the respective apertures  64 ,  56  in the motor flange  60  and the pump housing flange  52  to secure the motor  22  to the pump housing  14 . As a result, the motor  22  can be mounted with respect to the pump housing  14  in four different orientations, thereby allowing external electrical connections (not shown) to the motor  22  to be conveniently oriented with respect to the support surface  40 . 
   Alternatively, the flange  60  of the motor  22  and the flange  52  of the pump housing  14  can incorporate a bolt pattern having more or less than four apertures, or other connection techniques can be used. Further, the bolt pattern on the pump housing flange  52  can be arranged to include a multiple of the apertures on the motor flange  60 , thereby allowing the motor  22  to be mounted to the pump housing  14  in a multiple of different orientations. In the illustrated embodiment, the apertures  56  in the pump housing flange  52  are threaded to receive the fasteners  68 . However, the apertures  64  in the motor flange  60  can alternatively be threaded to receive the fasteners  68 . A handle  72  can also be coupled to the motor flange  60  as a convenience when transporting or installing the pump  10 . 
   The inlet portion  30  of the pump housing  14  includes an inlet  76  for fluidly coupling an inlet conduit  80  (see  FIG. 2 ) to the pump housing  14 . The inlet conduit  80  can be configured as a pipe, a hose, or any other fluid-carrying body that delivers a fluid (e.g., water) to the inlet portion  30  of the pump housing  14  from a fluid source at an initial pressure. As shown in  FIG. 2 , the inlet  76  is defined along an axis  84  substantially perpendicular with the central axis  26 . The inlet  76  can be threaded to receive a fluid coupling  88  for connecting the inlet conduit  80 . 
     FIG. 1  shows the tubular discharge portion  34  enclosing most of the pump assembly  18 . The tubular discharge portion  34  includes an outlet  92  defined along the central axis  26  for fluidly coupling an outlet conduit  96  (see  FIG. 2 ) to the pump housing  14 . Like the inlet conduit  80 , the outlet conduit  96  can be configured as a pipe, a hose, or any other fluid-carrying body that transports pressurized fluid from the pump  10 . Like the inlet  76 , the outlet  92  can be threaded to receive a fluid coupling  100  for connecting the outlet conduit  96 . The pump assembly  18  pressurizes the fluid as the fluid flows from the inlet  76  to the outlet  92 . The outlet conduit  96  then carries the pressurized fluid from the pump housing  14 . In alternative embodiments of the invention, the pump assembly  18  can be configured to pressurize the fluid as the fluid flows from the outlet  92  to the inlet  76 , effectively reversing the flow through the pump  10 . 
   With reference to  FIG. 1 , the pump assembly  18  includes a pump shaft  104  and a plurality of hydraulic stages  108  arranged end-to-end along the pump shaft  104 . As shown in  FIG. 2 , the pump shaft  104  is supported for rotation in the pump housing  14 . As shown in  FIGS. 1 and 2 , each hydraulic stage  108  includes an impeller  112  coupled for rotation with the pump shaft  104 . In the illustrated embodiment, the pump shaft  104  includes a hexagonal outer shape or surface and the impellers  112  include respective hubs  114  having hexagonal bores  118  to receive the hexagonal pump shaft  104 . Alternatively, the impellers  112  can be permanently connected to the pump shaft  104  by methods such as, for example, welding or brazing. 
   Each hydraulic stage  108  also includes a suction cap  122  upstream of the impeller  112  and a diffuser  126  downstream of the impeller  112 . U.S. Pat. No. 5,407,323, incorporated herein by reference in its entirety, includes additional disclosure relating to the suction cap  122 , impeller  112 , and the diffuser  126 . In the illustrated pump assembly  18 , twelve hydraulic stages  108  are shown. However, alternative embodiments of the invention can incorporate more or fewer than twelve hydraulic stages  108 . Accordingly, alternative embodiments of the invention can include only a single hydraulic stage  108 . 
   Each hydraulic stage  108  is individually operable to pressurize the fluid in the pump housing  14 . The pressure of the fluid in the pump housing  14  is incrementally increased due to each subsequent stage  108  as the fluid flows from the inlet  76  to the outlet  92 . In each stage  108 , the suction cap  122  guides the fluid toward the impeller  112 , which accelerates the fluid radially outwardly. The accelerated fluid is then slowed by the diffuser  126 , converting a portion of the energy of the accelerated fluid into pressure. The suction cap  122  of an adjacent stage  108  then guides the pressurized fluid into the impeller  112  of the adjacent stage  108  for additional pressurizing. 
   With reference to  FIG. 2 , a retainer in the form of a C-clip  130  is coupled to the discharge end of the pump shaft  104  downstream of the hydraulic stages  108 . The C-clip  130  prevents the hydraulic stages  108  from sliding off the discharge end of the pump shaft  104 . At the inlet end of the pump shaft  104 , a portion of the hexagonal-shaped pump shaft  104  (see  FIG. 1 ) is drivably coupled to an output shaft  132  of the motor  22  via an interface or a coupling  134 . In some embodiments, the output shaft  132  includes a threaded portion  138  and a shoulder  142  adjacent the threaded portion  138 . As shown in  FIG. 2 , the coupling  134  includes an internally-threaded portion  146  configured to engage the threaded portion  138  of the output shaft  132 , and an internal hexagonal-shaped portion  150  configured to receive the hexagonal-shaped pump shaft  104 . In the illustrated embodiment, the hexagonal-shaped pump shaft  104  is press-fit into the internal hexagonal-shaped portion  150  of the coupling  134 . Accordingly, the coupling  134  is not easily disconnected from the pump shaft  104 . 
   With reference to  FIG. 1 , a seal cap or a seal plate  154  is positioned between the motor  22  and the pump housing  14  to at least partially seal the pump housing  14 . The seal plate  154  includes an aperture  158  to receive the output shaft  132  of the motor  22 . In alternative embodiments of the invention, the pump shaft  104  can extend through the aperture  158  in the seal plate  154 , and the coupling  134  can be positioned between the motor  22  and the seal plate  154 . When the motor  22  is coupled to the pump housing  14 , the seal plate  154  is forced against the flange  52  of the pump housing  14 . An O-ring  162  can enhance sealing between the seal plate  154  and the flange  52  of the pump housing  14  to substantially prevent leakage between the seal plate  154  and the flange  52  of the pump housing  14 . Alternatively, the O-ring  162  can be in the form of a differently configured seal (e.g., a square ring, quad ring, etc.). 
   As shown in  FIGS. 1 ,  6   a , and  6   b , a seal assembly in the form of a mechanical seal  166  is utilized to substantially prevent leakage between the output shaft  132  and the aperture  158  in the seal plate  154 . The mechanical seal  166  generally includes a stationary seal  170  fixed to the seal plate  154  and a rotating seal  174  fixed for rotation with the output shaft  132 . The stationary seal  170  includes an elastic cup or ring  178  and a ceramic ring  182  extending from the elastic ring  178 . In the illustrated embodiment, the elastic ring  178  can be made from rubber or any other elastomer. The elastic ring  178  is sized and configured to be received into a recess  186  formed in the seal plate  154 . The elastic ring  178  can be pressed into the recess  186  to provide a seal between the outer periphery of the elastic ring  178  and the inner periphery of the recess  186  as is known in the art. As shown in  FIGS. 6   a  and  6   b , the ceramic ring  182  includes a stationary surface  190  axially spaced from an interior surface  194  of the seal plate  154 . 
   The rotating seal  174  includes a housing  198  having coupled thereto a carbon ring  202  and an elastic shaft seal  206 . The carbon ring  202  is concentric with the ceramic ring  182 , and includes a rotating surface  210  facing the stationary surface  190  of the stationary seal  170 . The elastic shaft seal  206  fits snugly against the output shaft  132  to provide a seal as is known in the art. The rotating seal  174  also includes a compression spring  214  biasing the rotating surface  210  against the stationary surface  190  to provide a seal between the rotating surface  210  and the stationary surface  190  as is known in the art. In the illustrated embodiment, the spring  214  is at least partially compressed between the housing  198  and the coupling  134  to provide the biasing force. As shown in  FIG. 2 , the coupling  134  is threaded onto the output shaft  132  until the coupling  134  abuts the shoulder  142  of the output shaft  132 , which determines the amount that the spring  214  is compressed and establishes the biasing force of the rotating surface  210  against the stationary surface  190 . The mechanical seal  166  and the seal plate  154  substantially prevents fluid from leaking out of the pump housing  14 . 
     FIGS. 1 and 2  illustrate a spacer  218  positioned between the seal plate  154  and the hydraulic stages  108 . When the pump  10  is assembled, the spacer  218  engages the seal plate  154  at one end and the suction cap  122  of the hydraulic stage  108  disposed closest to the inlet  76 . The spacer  218  is positioned to intersect the axis  84  of the inlet  76 . The spacer  218  includes a plurality of apertures  222  that allow fluid to flow from the inlet  76  through the spacer  218 . In addition to engaging the seal plate  154  when the pump  10  is assembled, the spacer  218  at least partially compresses the suction caps  122  and the diffusers  126  of the respective hydraulic stages  108  against each other, and at least partially compresses the diffuser  126  closest to the outlet  92  against a shoulder  224  inside the tubular discharge portion  34  of the pump housing  14 . This prevents significant leakage of fluid between adjacent hydraulic stages  108 . 
   With reference to  FIGS. 3-4   b , the serviceability of the pump  10  is improved over conventional pumps. More particularly, the installation and removal of the motor  22  and pump assembly  18  with respect to the pump housing  14  is simplified compared to conventional pumps. To remove the pump assembly  18  from the pump housing  14 , as shown in  FIG. 3 , the fasteners  68  are removed from the pump housing  14 , and the motor  22  and pump assembly  18  can be pulled out from the pump housing  14  along the central axis  26  as a single unit. The C-clip  130  (or other retention device) on the pump shaft  104  enables the entire stack of hydraulic stages  108  to be pulled out of the pump housing  14  with the pump shaft  104  and the motor  22 . As a result, the inlet conduit  80  can remain connected to the inlet  76  of the pump housing  14 , and the outlet conduit  96  can remain connected to the outlet  92  of the pump housing  14  during pump servicing. 
   The coupling  134  can be disengaged from the output shaft  132  to separate the motor  22  from the pump assembly  18 . With reference to  FIG. 4   a , an end cap  226  of the motor  22  can be removed to expose the end of the output shaft  132 . The end of the output shaft  132  includes a slot  230  that can be engaged by a tool (e.g., a screwdriver  234 ) to rotationally secure the output shaft  132 . Alternatively, other methods of securing the output shaft  132  relative to the housing of the motor  22  can be utilized. 
   Further, another tool (e.g., an open-end wrench  238 ) can be inserted through one of the apertures  222  of the spacer  218  to engage the hexagonal-shaped pump shaft  104 . The wrench  238  can then incrementally rotate the pump shaft  104 , thereby causing the threaded portion  146  of the coupling  134  to disengage the threaded portion  138  of the output shaft  132 . Alternatively, the wrench  238  can be used to rotationally secure the pump shaft  104 , and the screwdriver  234  can be rotated to rotate the output shaft  132  relative to the coupling  134  to disengage the threaded portion  146  of the coupling  134  from the threaded portion  138  of the output shaft  132 . Upon disengaging the coupling  134  and the output shaft  132  (see  FIG. 4   b ), the motor  22  can be moved away from the spacer  218  to expose the seal plate  154 . Further, rotating seal  174  of the mechanical seal  166  can be removed from the output shaft  132 , the seal plate  154  can be disengaged from the motor  22 , and the stationary seal  170  of the mechanical seal  166  can be disengaged and removed from the seal plate  154 . At this time, the mechanical seal  166 , the seal plate  154 , and/or the O-ring  162  can be inspected, repaired, and/or replaced. 
   The coupling  134  can be removed from the pump shaft  104  to remove the hydraulic stages  108  from the pump shaft  104 . To remove the coupling  134 , the coupling  134  can be pulled from the pump shaft  104 , however, sufficient force is required to overcome the resistance of the press fit between the internal hexagonal-shaped portion  150  of the coupling  134  and the hexagonal-shaped pump shaft  104 . Any of a number of different tools can be utilized to assist a user with pulling the coupling  134  from the pump shaft  104 . Alternatively, the hydraulic stages  108  can be removed from the discharge end of the pump shaft  104  opposite the coupling  134 . To accomplish this, the C-clip  130  must be removed from the pump shaft  104 . 
   Once the coupling  134  is disengaged from the pump shaft  104 , one or more of the hydraulic stages  108  can be removed from the pump shaft  104  for inspection, repair, or replacement. The installation of the motor  22  and pump assembly  18  into the pump housing  14  is the reverse of the process outlined above. 
   With reference to  FIG. 5 , the output shaft  132  and the coupling  134  can utilize a slip-fit connection rather than the threaded connection. For example, the output shaft  132  can include an external flat  242 , and the coupling  134  can include an internal flat  246  configured to engage the external flat  242  of the output shaft  132 . Alternatively, the output shaft  132  can include a plurality of splines, and the coupling  134  can include a plurality of internal splines configured to engage the splines on the output shaft  132 . Such slip-fit connections can allow the motor  22  to be removed from the pump housing  14  separately from the pump assembly  18 . As a result, if only the motor  22  required servicing and/or replacement, the pump assembly  18  can be left in the pump housing  14 . 
   With reference to  FIGS. 6   a  and  6   b , the pump  10  is shown mounted in a substantially vertical orientation with fluid in the pump housing  14 . The level of the fluid is represented by line L. As shown in  FIGS. 6   a  and  6   b , the interface between the stationary surface  190  and the rotating surface  210  is substantially submerged in the fluid beneath line L. By maintaining both of the stationary and rotating surfaces  190 ,  210  submerged in the fluid, heat due to friction between the surfaces  190 ,  210  can be dissipated into the fluid. If the surfaces  190 ,  210  do not remain substantially submerged in the fluid, the heat due to friction can build up and possibly damage the mechanical seal  166 . 
   During start-up of the pump  10 , air trapped in the system typically accumulates toward the top of the seal plate  154 . As the trapped air is eventually worked out of the system, the fluid level is allowed to rise above line L. The illustrated seal plate  154  provides sufficient spacing between the stationary surface  190  and the interior top surface  194  of the seal plate  154  to allow accumulation of the trapped air while maintaining the stationary and rotating surfaces  190 ,  210  substantially submerged in the fluid. Such spacing between the fluid at line L and the interior top surface  194  of the seal plate  154  can define a substantially annular air entrapment chamber  250 . Conventional pumps do not provide such an air entrapment chamber, thereby causing the seals of the conventional pumps to often run dry during the start-up period of the conventional pumps. 
   Various aspects of the present invention are set forth in the following claims.