Abstract:
A condensate pump for an HVAC system includes a reservoir, a unitary top support plate, and a cover. A pump motor, an impeller pump, a float, and control electronics are mounted on the unitary top support plate. The transition from the cylindrical volute chamber to the tangential output port of the impeller pump has a swept diagonal surface that creates a gradual transition from the cylindrical volute chamber to the tangential output port. The gradual transition minimizes the pulsing. An intake profile with a concave surface extends from the center of the impeller and matches a complementary intake profile extending from the bottom of the reservoir. Vortex inhibiting vanes are molded into the bottom of the reservoir adjacent the central intake port of the impeller pump to break up any induced vortex within the reservoir.

Description:
CLAIM OF PRIORITY 
       [0001]    This application claims priority from U.S. Provisional Patent Application Ser. No. 60/956,741 filed on Aug. 20, 2007, which is incorporated herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a condensate pump that collects condensate water from the evaporator of an HVAC system and pumps the condensate water to another location for disposal. More specifically, the condensate pump of the present invention includes an improved impeller pump, an improved component mounting assembly, and an improved reservoir attachment mechanism. 
       BACKGROUND OF THE INVENTION 
       [0003]    A condensate pump is used in an HVAC system to collect condensate water from the evaporator of the HVAC system and to pump the condensate water to a remote location for disposal. Particularly, the condensate pump typically comprises a reservoir, an impeller pump for pumping the water out of the reservoir to the remote location, and an electric motor to drive the impeller pump. A float detects the level of condensate water in the reservoir and activates control circuitry to control the operation of the electric motor. 
         [0004]    Condensate pumps are often located in extreme environments and are subjected to moisture, heat, and cold. Moreover, condensate pumps are often installed in inaccessible locations where maintenance is difficult, and therefore reliability over many years is necessary. Further, the condensate pump should operate quietly and without excessive buildup of heat from the operation of the electric motor. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention addresses the issues raised by the installation of a condensate pump in an extreme environment. Particularly, the condensate pump of the present invention is capable of operating reliably in such an extreme environment over an extended period of time. Further, the condensate pump of the present invention is designed to operate quietly and efficiently. 
         [0006]    In order to achieve the objects outlined above, the condensate pump of the present invention embodies a number of features that together produce an improved condensate pump. The condensate pump of the present invention includes a reservoir and a unitary top support plate, which forms the backbone of the condensate pump. The major components of the condensate pump are mounted to the unitary top support plate. In order to mount the condensate pump components, the unitary top support plate has an impeller pump support structure, a pump motor support structure, a cover support structure, a control circuitry support structure, and a float assembly support structure. A pump motor, a motor cover, an impeller pump, a float assembly, and control circuitry are mounted on the unitary top support plate by means of the respective support structures. 
         [0007]    With respect to quiet operation, the pump motor is mounted by means of rubber bushings to the unitary top support plate to isolate the vibrations of the motor and heat generated by the motor from the unitary top support plate. Further, the unitary top support plate is tightly mounted to the top of the reservoir by means of a snap connection so that the unitary top support plate, with its mounted components cannot vibrate on top of the reservoir. 
         [0008]    Quiet operation is also enhanced by the design of the cylindrical volute chamber of the impeller pump. Particularly, the transition from the cylindrical volute chamber to the tangential output port of the impeller pump has a swept diagonal surface that creates a gradual transition from the cylindrical volute chamber to the tangential output port. The gradual transition minimizes the pulsing that occurs each time the water between successive blades of the impeller rushes through the output port of the volute chamber. The reduction of pulsing by the smooth transition to the tangential output port increases efficiency and reduces noise of the impeller pump. 
         [0009]    In addition, in order to promote a constant flow of water into the central intake port of the volute chamber of the impeller pump, a reservoir intake profile with a concave surface and vortex inhibiting vanes are molded into the bottom of the reservoir adjacent the central intake port of the impeller pump. The vortex inhibiting vanes break up any vortex within the reservoir induced by the action of the impeller pump, and the reservoir intake profile directs the water upward in a smooth transition as it flows toward the central intake port of the impeller pump. In addition, the impeller has a matching impeller intake profile with a concave surface centered on the impeller and extending toward the reservoir intake profile to complete the flow transition of the water into the central intake port. The intake profiles and the vortex inhibiting vanes help assure a constant flow of water into the central intake port of the impeller pump thereby minimizing the intake of air by the impeller pump. Minimizing the intake of air by the impeller pump increases the efficiency of the impeller pump and reduces noise resulting from the intake of air. 
         [0010]    Further objects, features and advantages will become apparent upon consideration of the following detailed description of the invention when taken in conjunction with the drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a front perspective view of the condensate pump in accordance with the present invention. 
           [0012]      FIG. 2  is a front elevation view of the condensate pump in accordance with present invention. 
           [0013]      FIG. 3  is a front elevation view of the condensate pump (with the reservoir and cover cut away) in accordance with the present invention. 
           [0014]      FIG. 4  is a front elevation view of the condensate pump (with the reservoir and cover removed) in accordance with the present invention. 
           [0015]      FIG. 5  is a back elevation view of the condensate pump (with the reservoir and cover cut away) in accordance with the present invention. 
           [0016]      FIG. 6  is a back elevation in view of the condensate pump (with the reservoir and cover removed) in accordance with the present invention. 
           [0017]      FIG. 7  is a top perspective view of the condensate pump (with the cover removed) in accordance with the present invention. 
           [0018]      FIG. 8  is a bottom perspective view of the condensate pump (with the reservoir and cover removed) in accordance with the present invention. 
           [0019]      FIG. 9  is a detailed top perspective view of the attachment mechanism between the reservoir and the unitary top support plate of the condensate pump in accordance with the present invention. 
           [0020]      FIG. 10  is an exploded detailed side perspective view of the snap connection between the reservoir and the unitary top support plate of the condensate pump in accordance with the present invention. 
           [0021]      FIG. 11  is an exploded end perspective view of the condensate pump in accordance with the present invention. 
           [0022]      FIG. 12  is side elevation view of the impeller pump of the condensate pump in accordance with the present invention. 
           [0023]      FIG. 13  is a bottom plan view of the impeller pump of the condensate pump in accordance with the present invention. 
           [0024]      FIG. 14  is a bottom plan view of the impeller pump (with its bottom cover removed) of the condensate pump in accordance with the present invention. 
           [0025]      FIG. 15  is a top plan view of the impeller pump of the condensate pump in accordance with the present invention. 
           [0026]      FIG. 16  is a top plan view of the impeller pump (with its top cover removed) of the condensate pump in accordance with the present invention. 
           [0027]      FIG. 17  is an end elevation view of the condensate pump in accordance with the present invention. 
           [0028]      FIG. 18  is a bottom perspective view of the impeller pump (with its bottom cover removed) of the condensate pump in accordance with the present invention. 
           [0029]      FIG. 19  is a top perspective view of the impeller pump (with its top cover removed) of the condensate pump in accordance with the present invention. 
           [0030]      FIG. 20  is a front perspective view of an alternative low profile embodiment of a condensate pump in accordance with the present invention. 
           [0031]      FIG. 21  is a front elevation view of the low profile condensate pump (with the reservoir and cover cut away) in accordance with the present invention. 
           [0032]      FIG. 22  is a front elevation view of the low profile condensate pump (with the reservoir and cover removed) in accordance with the present invention. 
           [0033]      FIG. 23  is a cross-section view of the impeller pump of the low profile condensate pump in accordance with the present invention. 
           [0034]      FIG. 24  is a top plan view of the bottom panel of the reservoir of the low profile condensate pump in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0035]    Turning to  FIG. 1-8  and  11 , a condensate pump  10  in accordance with the present invention comprises a reservoir  12  and a unitary top support plate  14 . The reservoir  12  comprises a water tight container with an open top defined by a periphery  28  ( FIG. 11 ). In one embodiment the reservoir comprises a front panel  16 , a back panel  18 , a left side panel  20 , a right side panel  22 , and a bottom panel  24 . The reservoir may be of any geometric shape. The reservoir  12  has rubber support legs  26  located on the four corners of the bottom panel  24 . The unitary top support plate  14  has a flange  30  ( FIGS. 4 ,  6 ,  8 , and  11 ) around its periphery which engages the periphery  28  of the reservoir  12 . In addition, hanger brackets  32  are mounted to the reservoir on the back panel  18 . The hanger brackets  32  are used to mount the reservoir  12 , on a wall or other elevated support in order to make later access to the condensate pump  10  in some cases easier. The reservoir  12  further has a trough  34  molded into the bottom panel  24  for directing water remaining in the reservoir to the low point in the reservoir. 
         [0036]    As shown in  FIGS. 1 ,  3 ,  5 ,  7 , and  11  the unitary top support plate  14  rests on the periphery  28  of the reservoir  12 . A condensate water outlet connector  72  is mounted on one end of the unitary top support plate  14 . The unitary top support plate  14  also has inlet openings  38  in the four corners of the unitary top support plate  14  ( FIG. 1 ). Plugs  40  cover the inlet openings  38  that are not in use. As shown in  FIGS. 3-8 , the unitary top support plate  14  includes impeller pump support structure comprising five downwardly extending pump support legs  36  ( FIGS. 4 and 6 ), a cover support structure comprising four upwardly extending cover support legs  44  ( FIG. 7 ), a pump motor support structure comprising plate segment  92  ( FIGS. 7 and 8 ), a control circuitry support structure comprising plate segment  94  ( FIG. 7 ), and a float assembly support structure comprising plate segment  96  ( FIG. 7 ). 
         [0037]    As shown in the  FIGS. 4 ,  7 , and  8 , an electric pump motor  50  is mounted on plate segment  92  of the unitary top support plate  14  by means of rubber motor mount bushings  84 , which isolate vibration and heat generated by the pump motor  50  from the unitary top support plate  14 . As shown in  FIGS. 3-6 , an impeller pump  62  having mounting legs  74  is connected to the unitary top support plate  14  by connecting the impeller pump mounting legs  74  to the downwardly extending support legs  36  of the unitary top support plate  14 . A driveshaft  68  extends between the pump motor  50  and the impeller pump  62 . 
         [0038]    Motor control circuitry  54  and a float assembly  48  are mounted on the unitary top support plate  14  on plate segments  94  and  96  respectively ( FIG. 7 ). The motor control circuitry  54  and the float assembly  48  are operatively connected to each other. The float assembly  48  monitors the level of condensate water in the reservoir  12 , and in response to movement of the float assembly  48 , the motor control circuitry  54  starts and stops the pump motor  50 . The operation of the motor control circuitry  54  and the float assembly  48  is described in greater detail in commonly owned U.S. patent application Ser. No. 11/277,445, filed Mar. 24, 2006, United States Patent Application Publication No. 20070224050, Sep. 27, 2007, which is incorporated herein by reference. 
         [0039]    With reference to  FIGS. 3-6 , a biostat tablet drawer  42  is slidably supported by the unitary top support plate  14 . The biostat tablet drawer  42  holds biostat tablets which are introduced into the condensate water to inhibit the growth of algae and other unwanted biological materials. The description and operation of the biostat tablet drawer  42  is described in greater detail in commonly owned U.S. patent application Ser. No. 11/277,445, filed Mar. 24, 2006, United States Patent Application Publication No. 20070224050, Sep. 27, 2007, which is incorporated herein by reference. 
         [0040]    The unitary top support plate  14  supports all of the major components, the pump motor  50 , the impeller pump  62 , the motor control circuitry  54 , the float assembly  48 , the biostat tablet drawer  42 , and the water outlet connector  72 . Consequently, the unitary top support plate  42  provides the backbone for the condensate pump  10 . By mounting the major components of the condensate pump to the unitary top support plate  14 , the opportunities for vibration or damage to the major components are reduced. The assembly is then completed by attaching the cover  46  to the unitary top support plate  14  by means of four cover screws  47  through the cover  46  into the cover support legs  44  ( FIG. 3 and 5 ) and by attaching the reservoir  12  to the unitary top support plate  14  by means of a snap connection  52  described in greater detail below. Thus assembled, the components of the condensate pump are firmly connected together to further reduce the opportunities for rattle due to vibration caused by the operation of the electric pump motor  50  and the impeller pump  62 . 
         [0041]    As illustrated in  FIGS. 9-11 , the snap connection  52  between the unitary top support plate  14  and the reservoir  12  ensures a tight connection between the unitary top support plate  14  and the reservoir  12 . The snap connection  52  comprises guide projections  86  on the front panel  16  and the back panel  18  of the reservoir  12 , hooking tabs  88  extending from the flange  30  of the unitary top support plate  14 , and keeper openings  90  in the front panel  16  and the back panel  18  of the reservoir  12  ( FIG. 11 ). In order to connect to the unitary top support plate  14  to the reservoir  12 , the unitary top support plate  14  is lowered on to the periphery  28  of the reservoir  12 . As the hooking tabs  88  engage the front panel  16  and the back panel  18  of the reservoir  12 , the front panel  16  and the back panel  18  are forced outwardly by the camming action of the hooking tabs  88 . Once the unitary top support plate  14  has been seated onto the periphery  28  of the reservoir  12 , the hooking tabs  88  engage the keeper openings  90  in the front panel  16  and the back panel  18  of the reservoir  12  to hold the unitary top support plate  14  onto the periphery  28  of the reservoir  12 . The guide projections  86  facilitate the positioning of the unitary top support plate  14  onto the periphery  28  of the reservoir  12 . Further, the guide projections  86  are used to pry the front panel  16  and the back panel  18  of the reservoir  12  outwardly in order to later disengage the hooking tabs  88  from the keeper openings  90  in order to remove the unitary top support plate  14  from the reservoir  12 . 
         [0042]    Turning to  FIGS. 12-19 , the impeller pump  62  has a cylindrical volute chamber  56  with an impeller  64  having impeller blades  66  mounted for rotation within. The volute chamber  56  is cylindrical in shape with a central intake port  60  and a tangential output port  58 . The tangential output port  58  is connected to outlet tube  70 , and the outlet tube  70  is connected to the water outlet connector  72  ( FIGS. 4 and 8 ). The impeller  64  is connected to impeller driveshaft  68  and is driven by the electric pump motor  50  ( FIG. 4 ). In operation, the impeller  64  draws condensate water from the reservoir  12  into the central intake port  60 . The impeller  64  then forces the condensate water out through tangential output port  68 , through outlet tube  70 , and through outlet connector  72 . 
         [0043]    In order to reduce noise of the impeller pump  62 , the tangential output port  58  has swept diagonal surfaces  76  ( FIGS. 14 ,  16 ,  17 ,  18 , and  19 ), which are beveled in order to provide a smooth and elongated transition from the radial motion of the water between each of the impeller blades  66  to the tangential direction of the tangential output port  58 . Absent the smooth and elongated transition created by the swept diagonal surfaces  76 , the water, in a conventional impeller pump, is forced to change immediately from a radial direction to a tangential direction causing a pronounced pounding action as each impeller blades  66  passes by the tangential output port  58 . By smoothing and elongating the transition, the water gradually changes direction from radial to tangential thereby resulting in far less pump noise. 
         [0044]      FIGS. 20-24  illustrate a condensate pump  110  that is virtually identical to the condensate pump  10  previously described except for the height of the reservoir  112 . The reference numerals in  FIGS. 20-24  are the same for the same parts in  FIGS. 1-19  except that the numeral  1  has been placed before each reference numeral in  FIGS. 20-24 . 
         [0045]    Because of the reduced height of the reservoir  112 , the condensate water entering the reservoir  112  through inlet openings  138  moves directly to the central intake port  160  ( FIG. 23 ) of the impeller pump  162 . Further, only a small amount of condensate water remains in the bottom of the reservoir  112  during operation of the impeller pump  162 . Consequently, the rotation of the impeller  164  in the impeller pump  162  induces a vortex flow of condensate water in the reservoir  112  below the central intake port  160  of the impeller pump  162 . Such a vortex flow of condensate water in the reservoir  112  tends to create an air pocket (like the eye of a hurricane) just below the central intake port  160  causing the impeller  164  to draw air through the central intake port  160  into the volute chamber  156 . Drawing air into the volute chamber  156 , not only reduces the efficiency of the impeller pump  162 , but also creates additional noise as the air creates turbulence inside the volute chamber  156 . In order to reduce the intake of air through the central intake port  160  of the volute chamber  156 , the present invention employs a set of vortex inhibiting vanes  182  molded into the bottom panel  124  of the reservoir  112 , an impeller intake profile  178  extending from the center of the impeller  164 , and a reservoir intake profile  180  molded into the bottom panel  124  of the reservoir  112  and extending toward the impeller intake profile  178  ( FIGS. 23 and 24 ). In operation, the vortex inhibiting vanes  182  are configured so that the induced vortex circulation within the reservoir  112  is broken up by the vortex inhibiting vanes  182 , and the water is directed in a laminar flow toward the central intake port  160 . Further, the reservoir intake profile  180  and the matching impeller intake profile  178  provide a smooth transition profile from horizontally flow of the water moving toward the central intake port  160 , to a vertical flow of the water into the impeller  164 , and finally to a horizontal flow between the impeller blades  166  of the impeller  164 . The smooth transition provided by the reservoir intake profile  180  and the matching impeller intake profile  178  reduces turbulence and therefore increases the efficiency of the pump and reduces the intake of air. 
         [0046]    While this invention has been described with reference to preferred embodiments thereof, it is to be understood that variations and modifications can be affected within the spirit and scope of the invention as described herein and as described in the appended claims.