Positive Displacement Pump Including Detectable Composite Non-Metallic Components

Abstract

A positive displacement pump is disclosed which includes a case that defines a pump cavity. A shaft and rotor, which are detachably connected together, are also included wherein the rotor is disposed within the pump cavity and the shaft passes through an opening in the proximal end of the case. The distal end of the shaft, in addition to being connected to the rotor, is also coupled to a fastener that couples a cover plate over the distal end of the shaft and over at least part of the base portion of the rotor. The opening in the proximal side of the case through which the shaft passes also accommodates a seal assembly. Access to the seal assembly is easily made by removing the head from the case and removing the rotor from the shaft. The seal assembly can be changed or serviced without removal of the shaft.

What is claimed is: 
     
         1 . A positive displacement pump comprising:
 a case including a proximal end with an opening and an open distal end that is detachably covered by a head;   a rotor including a base, the base including a proximal side, a distal side and an opening;   a shaft including a proximal end and a distal end that extends through the opening in the proximal end of the case before being coupled to the opening in the base of the rotor, the distal end of the shaft being coupled to the base of the rotor by a fastener, the fastener sealably coupling a cover plate to the distal end of the shaft, the cover plate extending radially outward from the shaft and sealably covering at least part of distal side of the base of the rotor;   the opening in the proximal end of the case accommodating a seal assembly, the distal end of the shaft passing through the seal assembly, the seal assembly sealably engaging the opening in the proximal end of the case, the shaft and the proximal side of the base of the rotor.   
     
     
         2 . The pump of  claim 1  further including a pin coupled to the head, the pin being received in an idler, the rotor including a plurality of distally extending teeth disposed around a periphery of the base of the rotor, the idler being rotatably disposed within the teeth of the rotor. 
     
     
         3 . The pump of  claim 1  wherein at least one of the case, rotor and head are fabricated from a metal-detectable polymer. 
     
     
         4 . The pump of  claim 2  wherein at least one of the case, rotor, idler, cover plate and head are fabricated from a metal-detectable polymer. 
     
     
         5 . The pump of  claim 1  wherein at least one of the case, rotor and head are fabricated from a metal coated with a metal-detectable polymer. 
     
     
         6 . The pump of  claim 2  wherein at least one of the case, rotor, idler, cover plate and head are fabricated from a metal coated with a metal-detectable polymer. 
     
     
         7 . The pump of  claim 2  wherein each of the case, rotor, idler, cover plate and head are fabricated from metal. 
     
     
         8 . The pump of  claim 2  wherein removal of the head, pin and idler from the case provides access to the fastener,
 removal of the fastener enables the cover plate and rotor to be pulled out of the head through the open distal end thereby providing access to the seal assembly without removal of the shaft; and 
 removal of the rotor enables the case to be removed from a bracket that supports the case. 
 
     
     
         9 . The pump of  claim 1  wherein a seal ring is trapped between the cover plate and the rotor. 
     
     
         10 . The pump of  claim 1  wherein a seal ring is trapped between the fastener and the cover plate. 
     
     
         11 . The pump of  claim 1  wherein the proximal end of the shaft extends through a bearing. 
     
     
         12 . A positive displacement pump comprising:
 a case having a proximal end with a through opening and an open distal end that is detachably covered by a head;   a rotor including a base with a plurality of teeth extending distally from a periphery of the base, the base including a proximal side and a distal side connected to the teeth and an opening for receiving a shaft;   the shaft including a proximal end supported by a bearing assembly and a distal end coupled to the opening in the rotor, the distal end of the shaft including an opening for receiving a fastener, the fastener coupling a cover plate to the distal end of the shaft, the cover plate extending radially outwards from the shaft and covering at least part of the distal side of the base of the rotor;   at least one seal being disposed between the cover plate and the rotor;   at least one seal being disposed between the fastener and the cover plate;   the distal end of the shaft passing through and being supported by a bearing assembly before passing through the opening in the proximal end of the case;   the opening in the proximal end of the case accommodating a seal assembly, the distal end of the shaft passing through the seal assembly before being coupled to the opening on the base of the rotor, the seal assembly sealably engaging the opening in the proximal end of the case, the shaft and the proximal side of the base of the rotor.   
     
     
         13 . The pump of  claim 12  further including a pin coupled to the head, the pin being received in an idler, the idler being rotatably disposed within the teeth of the rotor. 
     
     
         14 . The pump of  claim 12  wherein at least one of the case, rotor and head are fabricated from a metal-detectable polymer. 
     
     
         15 . The pump of  claim 13  wherein at least one of the case, rotor, idler, cover plate and head are fabricated from a metal-detectable polymer. 
     
     
         16 . The pump of  claim 12  wherein at least one of the case, rotor and head are fabricated from a metal coated with a metal-detectable polymer. 
     
     
         17 . The pump of  claim 13  wherein at least one of the case, rotor, idler, cover plate and head are fabricated from a metal coated with a metal-detectable polymer. 
     
     
         18 . The pump of  claim 13  wherein the case, rotor, idler, cover plate and head are fabricated from metal. 
     
     
         19 . The pump of  claim 13  wherein removal of the head, pin and idler from the case provides access to the threaded fastener, removal of the threaded fastener enables the cover plate and rotor to be drawn out of the head through the open distal end thereby providing access to the seal assembly without removal of the shaft. 
     
     
         20 . A method for replacing a seal assembly of a sanitary/hygienic pump, the method comprising:
 removing a head, pin and idler from a distal end of a case of the pump, the head being coupled to the pin and idler, removal of the head, pin and idler exposing a fastener;   removing the fastener from a distal end of a shaft that is detachably coupled to a proximal end of a rotor and removing a cover plate that was trapped between the fastener and the distal end of the shaft;   removing the rotor thereby exposing the seal assembly disposed in an opening in the proximal end of the case and through which the shaft passes;   removing the seal assembly without removing the shaft;   removing the casing from the bracket; and reassembling the casing, seal assembly, rotor, seal plate, fastener, idler and head without adjusting a rotor end clearance.