Cryogenic Pump

Abstract

A cryogenic pump is typically used to supply high pressure natural gas to an engine. The pump has a piston operable to discharge cryogenic liquid from a pumping chamber within a pump housing. The cryogenic liquid exits the chamber through an outlet port in which a check valve is positioned. The check valve has a valve member which is loaded by a spring and is retained by a retaining member accessible from outside the housing. The check valve has an inlet which is axial with the valve member and an outlet which is transverse to the axis of the valve member.

What is claimed is: 
     
         1 . A cryogenic pump for pumping liquid natural gas comprising:
 (a) a piston operable to discharge cryogenic liquid from a pumping chamber within a pump housing;   (b) an outlet port from said pumping chamber, said outlet port disposed in said pump housing; and   (c) a check valve in said outlet port, said check valve comprising:
 (i) a valve member; 
 (ii) a demountable retaining member accessible from the exterior of said pump housing; 
 (iii) an inlet axial with said valve member and transverse to the axis of said pumping chamber of said cryogenic pump; and 
 (iv) an outlet transverse to the axis of said valve member and parallel to the axis of said pumping chamber of said cryogenic pump. 
   
     
     
         2 . The cryogenic pump of  claim 1 , wherein said retaining member comprises a sleeve for guiding said valve member. 
     
     
         3 . The cryogenic pump of  claim 2 , wherein said sleeve is integral with said retaining member. 
     
     
         4 . The cryogenic pump of  claim 1 , wherein said valve member is spring-loaded. 
     
     
         5 . The cryogenic pump of  claim 4 , wherein said valve member comprises a cylindrical body and a frustoconical head, which, when said check valve is in its closed position, sealingly engages, under bias of said spring, a complementary valve seat formed in said pump housing. 
     
     
         6 . The cryogenic pump of  claim 5 , wherein said head is formed from plastic material. 
     
     
         7 . The cryogenic pump of  claim 5 , wherein said head is formed from polytetrafluoroethylene. 
     
     
         8 . The cryogenic pump of  claim 5 , wherein said valve seat is formed from metal. 
     
     
         9 . The cryogenic pump of  claim 8 , wherein said valve seat is formed from stainless steel. 
     
     
         10 . The cryogenic pump of  claim 4 , wherein said spring is a compression spring. 
     
     
         11 . The cryogenic pump of  claim 10 , wherein said compression spring is seated in a detent formed in said retaining member.