Patent Publication Number: US-11035375-B1

Title: Pump drip control system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to provisional U.S. Application 62/690,039, filed Jun. 26, 2018, entitled “Pump Drip Control System”, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure is directed to spa pumps, and in particular, to pump drip control systems. 
     Description of Related Art 
     In spa pump systems, water leakage often occurs at the interface between the pump and the motor, in particular, where the pump impeller shaft and motor shaft mate outside a pump outlet housing. The pump is purposely designed to have a predetermined amount of leakage for lubrication purposes. This water then typically evaporates due to friction of the motor. However, on occasion, a small amount of this water leaks out of the pump housing. If water leakage is visible, repair personnel and spa owners believe there is a problem with the pump and will often replace these pumps prematurely, even though the motor is fully functional. This is a major problem in spa pump systems because usually, the leakage is small and does not require replacement of the pump. The vast majority of replaced pumps have relatively minor leaks and seal leakage is the predominate cause of spa pump return. For this reason, a pump drip control or collection system is needed to collect the leakage and allow it to evaporate or drain to an out of site location and thus, prevent premature replacement of the pump. 
     SUMMARY OF THE INVENTION 
     In accordance with an embodiment of the present disclosure, a pump drip control system for attachment to a pump assembly comprising a pump housing and an impeller shaft extending through a seal boss on the pump housing includes a leakage collection chamber located within the pump housing. The impeller shaft is associated with an impeller and the impeller shaft is sealingly engaged with the pump housing via a shaft seal. The impeller shaft is associated with a rotor shaft extending out of the pump housing and a motor for rotating the impeller. The leakage collection chamber has a first end and a second end and defines an interior volume. The first end is in sealing engagement with an outer surface of the seal boss. A portion of the impeller shaft is received within the interior volume of the leakage collection chamber. A drip cap is engaged with the second end of the leakage collection chamber. The drip cap includes a circumferential channel and a gathering chamber. The circumferential channel defines a circumferential flow path to the gathering chamber. The pump drip control system further includes a slinger assembly defining an aperture. The impeller shaft is received with the aperture of the slinger assembly and is in sealing engagement with the slinger assembly. The slinger assembly is positioned on the portion of the impeller shaft received within the leakage collection chamber, so that, in operation, the slinger assembly directs liquid leakage from the impeller shaft to the drip cap. The circumferential channel within the drip cap then directs the liquid along the circumferential flow path and into the gathering chamber. The gathering chamber can hold a predetermined amount of liquid until the liquid evaporates. 
     A liquid exit port can be associated with the gathering chamber. The liquid exit port can include an attachment portion associated therewith configured for attachment with one of a tube, hose, pipe, or other known device for draining excess liquid from the gathering chamber. This liquid can be drained to a pan located underneath the spa or within a wall portion of the spa and eventually drained therefrom. 
     The drip cap includes a central aperture configured to receive a rotor shaft extending from a pump motor. The gathering chamber of the drip cap is configured such that a majority of the volume of the gathering chamber is located below the central aperture such that the excess liquid can be evaporated or drained out of the gathering chamber to minimize leaking through the central aperture. The drip cap includes an annular gap between the central aperture and the rotor shaft so that excess liquid that exceeds a volume of the gathering chamber can exit the leakage collection chamber through the annular gap. 
     The drip cap includes a sidewall portion. According to one embodiment, this sidewall portion includes a housing seal configured for sealingly engaging the drip cap to the second end of the leakage collection chamber. According to another embodiment, the drip cap includes a sidewall portion defining an inner circumferential ledge configured to receive an O-ring wherein this O-ring is capable of sealingly engaging the second end of the leakage collection chamber. 
     According to one embodiment, the drip cap can include at least one stop to limit axial movement of the cap to a position that will maintain a seal of the cap with the housing. 
     In accordance with another embodiment of the present disclosure, a drip cap is provided for use with a leakage collection chamber located within a pump housing. The leakage collection chamber has a first end and a second end and defines an interior volume. The drip cap is configured for sealingly engaging the second end of the leakage collection chamber. The drip cap comprises an end wall and at least one sidewall, wherein at least one of the end wall and sidewall include a circumferential channel and a gathering chamber. The circumferential channel defines a circumferential flow path to the gathering chamber to direct liquid leakage from the leakage collection chamber to the circumferential channel within the drip cap and along the circumferential flow path and subsequently into the gathering chamber. 
     A liquid exit port is associated with the gathering chamber. This liquid exit port is configured for attachment with one of a tube, hose, pipe, or other known device for draining excess liquid from the gathering chamber. An attachment member, associated with the liquid exit portion, can extend from an outer surface of the cap for attachment to the tube, hose, pipe, or other known device. The tube, hose, pipe, or other known device can drain the water to a location that is underneath the spa or tub and through an exit drain for the spa. 
     According to one embodiment, the sidewall of the cap includes a housing seal configured to sealingly engage the second end of the leakage collection chamber. According to another embodiment, the sidewall of the cap includes a portion that defines an inner circumferential ledge configured to receive an O-ring wherein the O-ring is capable of sealingly engaging the second end of the leakage collection chamber. 
     The drip cap can include at least one stop to limit axial movement of the cap to a position that will maintain a seal of the cap with the housing. 
     In accordance with another embodiment of the present disclosure, a method for reducing leakage from a pump housing including an impeller shaft extending through a seal boss on the pump housing comprises providing a leakage collection chamber within the pump housing. The leakage collection chamber has a first end and a second end and defines an interior volume, wherein the first end is in sealing engagement with an outer surface of the seal boss, and a portion of the impeller shaft is received within the interior volume. The method further comprises providing a drip cap, wherein the drip cap includes a circumferential channel and a gathering chamber, and wherein the circumferential channel defines a circumferential flow path to the gathering chamber. The method further includes sealingly engaging the drip cap with the second end of the leakage collection chamber and mounting a slinger assembly on the impeller shaft, wherein the slinger assembly is positioned on the portion of the impeller shaft received within the leakage collection chamber and wherein, in operation, the slinger assembly directs liquid leakage from the impeller shaft to the drip cap and the circumferential channel within the drip cap which directs the liquid along the circumferential flow path and subsequently into the gathering chamber. 
     The drip cap can include a liquid exit port associated with the gathering chamber and the method includes attaching one of a tube, hose, pipe, or other known device with the exit port to drain excess liquid from the gathering chamber. A separate attachment member can be provided for securing the tube, hose, pipe, or other known device with the liquid exit port. 
     The drip cap includes a central aperture and the method includes mounting the drip cap on a rotor shaft extending from a pump motor. The drip cap is mounted on the rotor shaft and engaged with the leakage collection chamber in an orientation wherein a majority of the volume of the gathering chamber is located below the central aperture such that the excess liquid can be evaporated or drained out of the gathering chamber to minimize leaking through the central aperture. The drip cap includes an annular gap between the central aperture and the rotor shaft so that excess liquid that exceeds a volume of the gathering chamber exits the leakage collection chamber through the annular gap. 
     According to one embodiment, the drip cap includes a sidewall portion and the method includes associating a housing seal with the sidewall portion. According to another embodiment, the sidewall of the drip cap includes an inner circumferential ledge and the method includes positioning an O-ring adjacent to this ledge. Upon placement of the drip cap on the second end of the leakage collection chamber, the housing seal or the O-ring sealingly engages the second end of the leakage collection chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side perspective view of a spa pump assembly including a drip cap in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a cross-section view of the spa pump assembly of  FIG. 1 , with the housing of the spa motor omitted, in accordance with an embodiment of the present disclosure; 
         FIG. 3  is an exploded view of the pump housing as indicated by section III in  FIG. 2 , in accordance with an embodiment of the present disclosure; 
         FIG. 4  is a cross-sectional view of the drip cap taken along line IV-IV of  FIG. 3  in accordance with an embodiment of the present disclosure; 
         FIG. 5  is a cross-sectional view of a drip cap mounted on the pump housing in accordance with an embodiment of the present disclosure; 
         FIG. 5A  is a top perspective view of the drip cap of  FIG. 5  in accordance with an embodiment of the present disclosure; 
         FIG. 5B  is a bottom perspective view of the drip cap of  FIG. 5  in accordance with an embodiment of the present disclosure; 
         FIG. 6  is a cross-sectional view of a drip cap mounted on the pump housing in accordance with an embodiment of the present disclosure; 
         FIG. 6A  is a top perspective view of the drip cap of  FIG. 6  in accordance with another embodiment of the present disclosure; and 
         FIG. 6B  is a bottom perspective view of the drip cap of  FIG. 6A  in accordance with an embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal” and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. 
     Reference is now made to  FIGS. 1-3  which show a spa pump assembly, generally indicated as  10 , including a pump drip control system, for use with a spa (not shown). The spa pump assembly includes an impeller  12  having an impeller shaft  14 . A pump motor  20  ( FIG. 3 ), enclosed within a motor housing  22  ( FIG. 1 ), includes a rotor shaft  24  that extends out of the motor housing  22  and is received within the impeller shaft  14 . The pump motor  20  applies a rotational force to the impeller  12 . A slinger assembly  16  includes a central aperture that is mounted on the rotor shaft  24 . The impeller  12  and impeller shaft  14 , along with the slinger assembly  16  are enclosed within a pump housing  30 . The impeller shaft  14  extends through a seal boss  31  on the pump housing  30 . A shaft seal  18  is provided that sealingly engages the impeller shaft  14  to the pump housing  30 . The pump housing  30  includes a water inlet portion  32  for drawing water therein via vacuum pressure and the water then exits the pump housing  30  through a water outlet portion  34  in an agitated form via the impeller  12 . The pump housing  30  includes a leakage collection chamber  36  for collecting water. The slinger assembly  16  can be located within this leakage collection chamber  36  to sling any water as shown by the arrows in  FIG. 3  that leaks through shaft seal  18  into the leakage collection chamber  36 . The leakage collection chamber  36  has a first end  37  and a second end  38  and defines an interior volume  39 . The first end  37  is in sealing engagement with an outer surface of the seal boss  31  and a portion of the impeller shaft  14  is received within the interior volume  39  of the leakage collection chamber  36 . 
     With continuing reference to  FIGS. 1-3  and with further reference to  FIGS. 4, 5A-5B , and  6 A- 6 B, a drip cap  50  cooperates with the second end  38  of the leakage collection chamber  36 , to trap any excess liquid or water that escapes through the shaft seal  18  and into the interior volume  39 . The leakage collection chamber  36  and second end  38  is defined by at least one sidewall  40 . The liquid or water is held within the interior volume  39  of the leakage collection chamber  36 , out of site from the spa owner and/or repair personnel, until it evaporates and/or is drained away. The drip cap  50  includes a circumferential channel  60  forming a circumferential flow path that empties into a gathering chamber  62 . The slinger assembly  16  is positioned on the portion of the impeller shaft  14  received within the leakage collection chamber  36  such that, in operation, the slinger assembly  16  directs liquid leakage from the impeller shaft  14  to the drip cap  50  and the circumferential channel  60  within the drip cap  50  which directs the liquid or water along the circumferential flow path and into the gathering chamber  62 . The gathering chamber  62  can hold a predetermined amount of liquid until the liquid evaporates. 
     A liquid exit port  64  can be associated with the gathering chamber  62 . The liquid exit port  64  can include an attachment portion  66  associated therewith configured for attachment with one of a tube, hose, pipe, or other known device capable of draining excess liquid from the gathering chamber  62 . This liquid can be drained to a pan (not shown) located underneath the spa or within a wall portion of the spa and eventually drained therefrom. Alternatively, the liquid can be drained to the same drain used to empty the contents of the spa. 
     The drip cap  50  includes the central aperture  58  configured to receive the rotor shaft  24  extending from the pump motor  20 . The gathering chamber  62  is configured such that when the drip cap  50  is mounted on the rotor shaft  24 , a majority of the volume of the gathering chamber  62  is located below the central aperture  58  so that the excess liquid gathers in the gathering chamber  62  and can be evaporated or drained out of the gathering chamber  62  to minimize leaking through the central aperture  58 . The drip cap  50  includes an annular gap  59  between the central aperture  58  and the rotor shaft  24  and wherein excess liquid that exceeds a volume of the gathering chamber  62  can exit the leakage collection chamber  36  through the annular gap  59 . 
     With continuing reference to  FIGS. 1-3  and with reference to  FIGS. 4, 5, 5A-5B, 6, and 6A-6B , the drip cap  50  comprises a cup-shaped member having an end wall  52  and at least one sidewall portion  54  defining an open portion  56 . The drip cap  50  includes the central aperture  58  adapted to fit on the rotor shaft  24 . The sidewall portion  54  fits about sidewall  40  of the pump housing  30  to close the second end  38  of the leakage collection chamber  36 . The drip cap  50  includes a circumferential channel  60  and a gathering chamber  62  wherein the circumferential channel  60  defines a circumferential flow path to the gathering chamber  62 . 
     The sidewall portion  54 , as shown in  FIGS. 2-4 , ( 54 A in  FIGS. 5A and 54B  in  FIG. 6A ) of the drip cap  50  can be secured to the sidewall  40  of the leakage collection chamber  36  by a friction fit, latches, detents, and any other well known securing technique. It can be appreciated that the drip cap  50  can be secured by a technique that allows the cap to be removed from the pump housing  30  and the leakage collection chamber  36 , so as to facilitate repairs within the pump housing or replacement of the drip cap  50 . Alternatively, the drip cap  50  can be permanently secured to the pump housing via adhesive or integrally joined to the pump housing  30  during manufacture. It is noted that  FIGS. 2 and 3  show the sidewall portion  54  of the drip cap  50  encompassing the sidewall  40  of the leakage collection chamber  36  of the pump housing  30 , however, it can appreciated that the arrangement of the sidewalls can be reversed such that the sidewall  40  of the leakage collection chamber  36  of the pump housing  30  encompasses the sidewall portion  54  of the drip cap  50 . It is also noted that the figures show the drip cap  50  as having a circular shape and the second end  38  of the leakage collection chamber  36  also having a circular shape, however, it can further be appreciated that the drip cap  50  and second end  38  can have other shapes as long as these shapes correspond with each other so that the drip cap  50  cooperates with the second end  38  to define the interior volume  39  of the leakage collection chamber  36 . 
     According to one embodiment, as shown in  FIGS. 5, 5A, and 5B , the drip cap, generally indicated as  50 A, includes a sidewall portion  54 A defining an inner circumferential ledge  70  configured to receive a sealing medium  71 , such as an O-ring, wherein this O-ring is capable of sealingly engaging the second end  38  of the leakage collection chamber  36 . It can be appreciated that other sealing mediums can be used such as a flowable sealant (i.e., silicone), grease, and the like. These sealing mediums can be used separately or in combination with each other. In this embodiment, the drip cap  50 A includes an inner diameter that forms the outer wall  72  of the O-ring groove and the inner circumferential ledge  70  forms the bottom wall of the O-ring groove. When the drip cap  50 A is mounted onto the second end  38  of the leakage collection chamber  36  of the pump housing  30 , an outer diameter of the sidewall  40  of the second end  38  becomes the inner wall of the O-ring groove. The seal  71  is a radial compression seal with axial movement stopped by the inner circumferential ledge  70 . According to one embodiment, the drip cap  50 A can include one or more externally disposed standoffs  74  to ensure that the drip cap  50 A is always pushed onto the second end  38  of the leakage collection chamber  36  to achieve a good O-ring seal. In other words, ends of the standoffs  74  abut against the motor housing so that the drip cap  50 A is maintained in a sealed position on the second end  38  of the leakage collection chamber  36 . The drip cap  50 A can include at least one internally disposed stop  76  to limit axial movement of the drip cap  50 A to a position that will maintain a seal of the drip cap  50 A with the second end  38  of the leakage collection chamber  36 . According to one embodiment, the at least one stop  76  can include a plurality of stops extending from the end wall  52  into the open portion  56  of the drip cap  50 A. The stops  76  abut against the sidewall  40  of the pump housing  30 . The stops  76  have a predetermined height to ensure that a distance from the second end  38  of the leakage collection chamber  36  is always the same, resulting in relatively consistent seal loading. 
     According to another embodiment, as shown in  FIGS. 6, 6A, and 6B , the drip cap, generally indicated as  50 B, can have a sidewall portion  54 B that includes a housing seal  80  configured for sealingly engaging the drip cap  50 B to the second end  38  of the leakage collection chamber  36 . The housing seal  80  can be in the form of an interference fit bead that radially presses against an outer surface of the sidewall  40  of the second end  38  of the leakage collection chamber  36 . Positioning members  82 , are such as in the form of circumferential stops, assist with the positioning of the drip cap  50 B on the second end  38  of the leakage collection chamber  36 . In this configuration, the friction of the housing seal  80  in the form of the interference fit bead keeps the drip cap  50 B in place. The drip cap  50 B is pushed onto the second end  38  of the leakage collection chamber  36  until the second end  38  bottoms out on outer sidewalls of the circumferential channel  60 . This design still maintains access to the circumferential channel  60 . Thus, any leakage is thrown out radially in any direction and will end up along the circumferential channel  60  and flow along the gravitation flow path created from the channel  60  to the gathering chamber  62  located at a bottom portion of the circumferential channel  60 . 
     As discussed above and shown in  FIGS. 5A-5B and 6A-6B , any liquid collected within the gathering chamber  62 , can be held therein until evaporated or, if the volume of the collected liquid exceeds a predetermined volume of the gathering chamber  62 , the liquid excess can be drained via liquid exit port  64 . This fluid exit port  64  can be in fluid communication with an attachment portion  66 , which can form a sealed connection to a tube, hose, pipe, or any other known device which drains the excess liquid away from the spa pump assembly  10 . The leakage control system of the present invention reduces the visibility of typical and/or intentional water leakage, which, in turn reduces the premature replacement of pumps. 
     While the present disclosure is satisfied by embodiments in many different forms, there is shown in the drawings, and described herein in detail, the preferred embodiments of the disclosure, with the understanding that the present disclosure is to be considered as exemplary of the principles of the disclosure and is not intended to limit the disclosure to the embodiments illustrated. Various other embodiments will be apparent to and readily made by those skilled in the art without departing from the scope and spirit of the disclosure. The scope of the disclosure will be measured by the appended claims and their equivalents.