Variable Capacity Centrifugal Pump Assembly

Abstract

A variable capacity centrifugal pump assembly including a bearing housing, an impeller shaft rotatably mounted within the bearing housing and projecting therefrom, a volute circumscribing a cavity therein, a plurality of differently sized impellers for mounting on the impeller shaft within the cavity, a wear plate secured to the bearing housing and a volute and defining a downstream end portion of the cavity, a plurality of differently configured annular front covers for mounting to an upstream end of the volute for varying the size and configuration of the cavity to accommodate one of a selected plurality of differently sized impellers. The suction intake is mounted to the upstream end of the selected cover for communicating the pipe assembly with inlet hoses of varying size whereby the capacity of the pump assembly can be varied by the selective matching of the front covers with the impellers.

What is claimed is: 
     
         1 . A variable capacity centrifugal pump assembly adapted for use with a plurality of preselected differently sized standard water inlet hoses to selectively provide pump performance characteristics associated with conventional centrifugal pumps configured for use with each of the preselected inlet hose sizes, said pump assembly comprising:
 a bearing housing; an impeller shaft rotatably mounted within said bearing housing and projecting therefrom in an upstream direction; a volute circumscribing a cavity therein; a plurality of differently sized impellers, a selected one of said impellers being mounted on said impeller shaft within said cavity; a wear plate secured to said bearing housing and said volute and defining a downstream end portion of said cavity; a plurality of differently configured annular front covers, a selected one of said front covers being mounted to an upstream end of said volute and defining an upstream end portion of said cavity and thereby varying the size and configuration of said cavity to accommodate a selected one of said plurality of differently sized impellers; and a suction intake mounted to an upstream end of said selected one of said front covers, said suction intake having a mounting plate at the upstream end thereof for releasably forming a sealing engagement with one of the preselected differently sized standard water inlet hoses, whereby any of said preselected inlet hoses can be sealably mounted to said upstream end of said suction intake and the capacity of the pump assembly can be varied by the selective matching of said front covers with said impellers to provide the pump performance characteristics associated with a conventional centrifugal pump configured for use with said selected inlet hose.   
     
     
         2 . The pump assembly of  claim 1  including the plurality of spacing members, one or more of said spacing members being disposed between said volute and the selected one of said covers to maintain a predetermined spacing between the selected impeller on said impeller shaft and said volute. 
     
     
         3 . The pump assembly of  claim 2  wherein said spacing members comprise annular discs of varying thickness. 
     
     
         4 . The pump assembly of  claim 1  wherein said suction intake includes a body portion defining a fluid flow passageway extending axially therethrough and communicating with said cavity in said volute, said mounting plate on said suction intake being disposed at an upstream end of said body portion, a second mounting plate at a downstream end of said body portion, said second mounting plate being disposed upstream of and adjacent to the selected cover and securing said suction intake to said selected cover and said volute, a priming section mount carried by said body portion, an opening in said body portion below said mount communicating said mount with said fluid flow passageway and a baffle carried by said body portion and extending downwardly at a predetermined angle of inclination into said fluid flow passageway below said opening in said body portion. 
     
     
         5 . The pump assembly of  claim 4  wherein said angle of inclination is about 25 degrees with respect to the horizontal. 
     
     
         6 . The pump assembly of  claim 1  wherein each of said front covers is of an annular configuration and defines a generally cylindrical body portion, a mounting flange extending radially from said body portion for securing a selected one of said front covers to and between said suction intake and said volute, said body portions of said front covers each circumscribing a fluid flow passageway therethrough and defining an annular outwardly inclined surface proximate an upstream end of said front cover, said outwardly inclined surface merging into a curvilinear inner wall surface terminating at a downstream end of said front cover and wherein said downstream end of each of said front covers defines a fluid inlet having a transverse dimension greater than the transverse dimension defined by said inlet end of said front cover. 
     
     
         7 . The pump assembly of  claim 6  wherein each of said covers defines a plurality of washout grooves extending through said tapered and curvilinear wall surfaces therein. 
     
     
         8 . The pump assembly of  claim 4  including the plurality of spacing members, one or more of said spacing members being disposed between said volute and the selected one of said covers to maintain a predetermined spacing between the selected impeller on said impeller shaft and said volute. 
     
     
         9 . The pump assembly of  claim 4  wherein each of said front covers is of an annular configuration and defines a generally cylindrical body portion, a mounting flange extending radially from said body portion for securing a selected one of said front covers to and between said suction intake and said volute, said body portions of said front covers each circumscribing a fluid flow passageway therethrough and defining an annular outwardly inclined surface proximate an upstream end of said front cover, said outwardly inclined surface merging into a curvilinear inner wall surface terminating at a downstream end of said front cover and wherein said downstream end of each of said front covers defines a fluid inlet having a transverse dimension greater than the transverse dimension defined by said inlet end of said front cover. 
     
     
         10 . The pump assembly of  claim 9  including the plurality of spacing members, one or more of said spacing members being disposed between said volute and the selected one of said covers to maintain a predetermined spacing between the selected impeller on said impeller shaft and said volute. 
     
     
         11 . The pump assembly of  claim 1  wherein said volute defines a water inlet end and a water outlet end and communicates said cavity therein with said inlet and outlet ends thereof and including a check valve disposed within said volute for regulating water flow therethrough to facilitate the priming of the pump and preventing back flow through said suction intake, said check valve comprising a valve cover secured to said volute, a cavity disposed in an underside of said cover, an annular valve seat removeably mounted in said volute proximate said outlet end thereof and a flexible flapper disc defining a base portion and a body portion, said base portion being disposed within said cavity in the underside of said cover between said cover and said volute and said body portion being disposed against said valve seat in sealing engagement therewith whereby water drawn by said selected one impeller through said suction intake, said selected one front cover and said inlet end of said volute abuts said flapper disc and causes said disc to flex proximate said secured base portion such that said body portion moves away from said seat to allow fluid flow therethrough and upon said valve seat becoming worn, said seat can be readily removed and replaced without the need to replace the volute.