Gear pump

Abstract

A gear pump for pumping a fluid while adjustably controlling a gap between gears and end plates of the gear pump housing. The gear gap is controlled by a gear gap adjustment mechanism operably associated with a gear shaft to move the gear and shaft along a longitudinal axis of the shaft. The gear pump can also include a removable and replaceable friction shield to adjust the gap between the gear and the end plate. The gear pump can further include a dynamic shaft seal assembly for adjusting the sealing about the shaft.

What is claimed as being new and desired to be protected by Letters Patent of the United States is as follows: 
     
         1 . A gear pump comprising:
 a pump housing having opposite ends;   at least one gear disposed within said pump housing, said gear having opposed and outwardly facing first and second ends, said gear being fitted to a shaft; and   at least one gear gap adjustment mechanism operably associated with said shaft, said gear gap adjustment mechanism having a first member attachable to said pump housing, a plug member received in said first member, and a plug shaft coupled to said shaft and cooperatively moveable with said plug member;   wherein said plug member, said plug shaft and said shaft being moveable along a longitudinal axis of said shaft.   
     
     
         2 . The gear pump of  claim 1 , wherein said plug member is rotatably received in said first member via a threaded section, and said plug member includes an inwardly extending plug ledge defining a bore configured to receive a section of said plug shaft therethrough. 
     
     
         3 . The gear pump of  claim 2 , further comprising a bearing adjacent said plug ledge and a plug shaft ledge of said plug shaft, wherein said bearing is configured to transfer longitudinal movement of said plug member to said plug shaft while allowing said plug shaft to rotate in relation to said plug member. 
     
     
         4 . The gear pump of  claim 2 , further comprising a bearing adjacent said plug ledge and a nut engaged with an outward end of said plug shaft, wherein said bearing is configured to transfer longitudinal movement of said plug member to said plug shaft while allowing said plug shaft to rotate in relation to said plug member. 
     
     
         5 . The gear pump of  claim 1 , wherein said plug shaft is threadably received in a bore defined in an end of said shaft. 
     
     
         6 . The gear pump of  claim 1 , wherein said plug member is releasably locked in position by at least one fastener through said first member. 
     
     
         7 . The gear pump of  claim 1 , wherein said gear gap adjustment mechanism further comprising a cap sealingly received in said plug member. 
     
     
         8 . The gear pump of  claim 1 , further comprising first and second end plates sealingly joined to said opposite ends of said pump housing, said first end plate having a first end plate shaft passage to receive a first portion of said shaft therethrough and a first mount on an inner side of said first end plate coaxial with said first end plate shaft passage, said second end plate having a second end plate shaft passage to receive a second portion of said shaft therethrough and a second mount on an inner side of said second end plate coaxial with said second end plate shaft passage. 
     
     
         9 . The gear pump of  claim 8 , further comprising a friction shield received in one of said first mount and said second mount, said friction shield is a removable plate secured to one of said first end plate and said second end plate respectively. 
     
     
         10 . The gear pump of  claim 9 , wherein said first end plate includes a bearing adjacent a sealing disc, said bearing and sealing disc being located in said first end plate shaft passage between said friction shield and said first member, said bearing and sealing disc being configured to receive said first portion of said shaft therethrough. 
     
     
         11 . The gear pump of  claim 9 , further comprising at least one shim positioned between said friction shield and one of said first end plate and said second end plate respectively, said shim is configured to adjust a gap between said friction shield and one of said first and second ends of said gear respectively. 
     
     
         12 . The gear pump of  claim 8 , further comprising a dynamic shaft seal assembly attachable to said second end plate, said dynamic shaft seal assembly defining a shaft passage configured to receive a second portion of said shaft therethrough, said dynamic shaft seal assembly comprising an internally defined chamber about said shaft, at least one sealing disc in said passage and about said shaft, at least one bearing adjacent said sealing disc and about said shaft, and a packing nut engageable with an end of said dynamic shaft seal assembly. 
     
     
         13 . The gear pump of  claim 12 , wherein said dynamic shaft seal assembly further comprising a ring adjacent said chamber and said sealing disc, said ring contacts a ledge formed in said shaft passage to retain grease in said chamber. 
     
     
         14 . The gear pump of  claim 12 , wherein said dynamic shaft seal assembly further comprising a coiled sealing element about said shaft and compressible by rotation of said packing nut. 
     
     
         15 . The gear pump of  claim 14 , wherein said dynamic shaft seal assembly further comprising a bushing adjacent said coiled sealing element and said packing nut, said bushing being configured to transfer compression to said coiled sealing element from rotation of said packing nut. 
     
     
         16 . The gear pump of  claim 12 , wherein said second end plate further comprising a sealing disc and a bearing in said second end plate shaft passage and adjacent said dynamic shaft seal assembly. 
     
     
         17 . The gear pump of  claim 1 , wherein said gear pump includes a first fluid port and a second fluid port configured to allow passage of a fluid pumped by said gear. 
     
     
         18 . The gear pump of  claim 1 , wherein said gear is shrink fitted to said shaft, and said gear is selected from the group consisting of double-helical gears, and V-shaped helical gears.