Water hammer arrester

Abstract

A water hammer arrester configured for connection with a plumbing system. The water hammer arrester has a cap assembly, a piston assembly, and a base assembly. The cap assembly receiving the piston assembly therein. The base assembly having a connector for connection with a plumbing fixture in the plumbing system.

I claim: 
     
         1 . A water hammer arrester, the water hammer arrester configured for connection with a plumbing system, the water hammer arrester comprising:
 a cap assembly, the cap assembly comprising a cap having an open first end and a closed second end, the cap defining an air chamber therein, the cap having a lower interior sidewall adjacent the open first end, the lower interior sidewall comprising at least one retention portion extending inwards there-from;   a piston assembly, the piston assembly comprising a piston configured for sliding movement within the air chamber as pressure in the connected plumbing system changes; and   a base assembly, the base assembly comprising a base having a first open end configured for connection with the open first end of the cap and a connector for connection with a plumbing fixture in the plumbing system, the first open end of the base defining an exterior chamber therein surrounded by an interior sidewall, wherein extending through the base is a passageway fluidly interconnecting the first open end with the connector, the exterior chamber configured for receiving therein the open first end;   wherein the retention portion is configured for retaining the piston within the air chamber after the piston is inserted through the open first end and into the cap assembly;   wherein the lower interior sidewall has a general circumference, wherein the lower interior sidewall has a circumference at the retention portion, and wherein the circumference at the retention portion is smaller than the general circumference;   wherein the piston has a circumference smaller than the general circumference, but greater than the circumference at the retention portion; and   wherein when the first open end of the base is connected with the open first end of the cap, the piston is locked within the air chamber.   
     
     
         2 . A water hammer arrester, the water hammer arrester configured for connection with a plumbing system, comprising:
 a cap assembly, the cap assembly comprising a cap having an open first end and a closed second end, the cap defining an air chamber therein, the cap comprising an exterior sidewall, the exterior sidewall comprising a lower exterior sidewall adjacent the open first end, the cap further comprising a lower interior sidewall adjacent the open first end, the lower interior sidewall comprising at least one retention portion extending inwards there-from;   a piston assembly, the piston assembly comprising a piston configured for sliding movement within the air chamber as pressure in the connected plumbing system changes, wherein the piston comprises a lock rim; and   a base assembly, the base assembly comprising a base having a first open end configured for connection with the open first end of the cap and a connector for connection with a plumbing fixture in the plumbing system, the first open end of the base defining an exterior chamber therein surrounded by an interior sidewall, wherein extending through the base is a passageway fluidly interconnecting the first open end with the connector, the exterior chamber configured for receiving therein the open first end;   wherein the retention portion is configured for retaining the piston within the air chamber after the piston is inserted through the open first end and into the cap assembly so that the lock rim is moved past the retention portion;   wherein the lower interior sidewall has a general circumference, wherein the lower interior sidewall has a circumference at the retention portion, and wherein the circumference at the retention portion is smaller than the general circumference;   wherein the piston has a circumference smaller than the general circumference, but greater than the circumference at the retention portion; and   wherein when the first open end of the base is connected with the open first end of the cap, the piston is locked within the air chamber.   
     
     
         3 . The water hammer arrester of  claim 2 , wherein when the piston is inserted through the open first end, the lock rim causes the cap to flex outwards at the retention portion to allow the lock rim to pass the retention portion, and wherein after the lock rim passes the retention portion the cap unflexes thereby temporarily retaining the piston within the cap. 
     
     
         4 . The water hammer arrester of  claim 2 , wherein when the first open end of the base is connected with the open first end of the cap, the lower interior sidewall is no longer able to flex outwards, thereby locking the piston within the air chamber. 
     
     
         5 . The water hammer arrester of  claim 4 , wherein the connection between the first open end of the base and the open first end of the cap is a solvent weld. 
     
     
         6 . The water hammer arrester of  claim 4 , wherein the connection between the first open end of the base and the open first end of the cap is a spin weld. 
     
     
         7 . The water hammer arrester of  claim 2 , wherein when the piston is inserted through the open first end, the lock rim causes the cap to flex outwards at the retention portion to allow the lock rim to pass the retention portion, wherein after the lock rim passes the retention portion the cap unflexes thereby temporarily retaining the piston within the cap, and wherein when the first open end of the base is connected with the open first end of the cap, the lower interior sidewall is no longer able to flex outwards, thereby locking the piston within the air chamber. 
     
     
         8 . The water hammer arrester of  claim 2 , wherein the piston comprises a head and a tail and wherein a portion of the head is generally dome-shaped. 
     
     
         9 . The water hammer arrester of  claim 2 , wherein the retention portion comprises at least one raised bump on the lower interior sidewall which extends away from the lower interior sidewall. 
     
     
         10 . The water hammer arrester of  claim 2 , wherein the retention portion is formed in the cap assembly before the piston is inserted into the cap assembly. 
     
     
         11 . The water hammer arrester of  claim 10 , wherein when the piston is inserted through the open first end, the lock rim causes the cap to flex outwards at the retention portion to allow the lock rim to pass the retention portion, wherein after the lock rim passes the retention portion the cap unflexes thereby temporarily retaining the piston within the cap, and wherein when the first open end of the base is connected with the open first end of the cap, the lower interior sidewall is no longer able to flex outwards, thereby locking the piston within the air chamber. 
     
     
         12 . The water hammer arrester of  claim 2 , wherein the base assembly comprises a plastic. 
     
     
         13 . The water hammer arrester of  claim 12 , wherein the plastic is selected from the group consisting of acetal homopolymers and polyamides. 
     
     
         14 . The water hammer arrester of  claim 2 , wherein the exterior sidewall extends from the open first end to the closed second end. 
     
     
         15 . The water hammer arrester of  claim 14 , wherein the exterior sidewall has the same outside diameter from the open first end to adjacent the closed second end. 
     
     
         16 . The water hammer arrester of  claim 2 , wherein the base comprises an outside surface which comprises a plurality of mechanical holding fixtures for better enabling a manufacturing tool to grasp the base assembly during assembly. 
     
     
         17 . The water hammer arrester of  claim 2 , wherein the cap comprises an outside surface which comprises a plurality of ears for better enabling a manufacturing tool to grasp the cap assembly during assembly. 
     
     
         18 . The water hammer arrester of  claim 2 , wherein the piston comprises an exterior surface defining at least one circumvolving channel configured for receiving therein at least one  0 -ring. 
     
     
         19 . The water hammer arrester of  claim 2 , wherein the retention portion comprises at least one raised bump on the lower interior sidewall which extends away from the lower interior sidewall, wherein when the piston is inserted through the open first end, the lock rim causes the cap to flex outwards at the retention portion to allow the lock rim to pass the retention portion, wherein after the lock rim passes the retention portion the cap unflexes thereby temporarily retaining the piston within the cap, and wherein when the first open end of the base is connected with the open first end of the cap, the lower interior sidewall is no longer able to flex outwards, thereby locking the piston within the air chamber. 
     
     
         20 . A method of assembling a water hammer arrester, the water hammer arrester configured for connection with a plumbing system, the method comprising the following steps:
 providing a cap assembly, the cap assembly comprising a cap having an open first end and a closed second end, the cap defining an air chamber therein, the cap having a lower exterior sidewall and a lower interior sidewall adjacent the open first end, the lower interior sidewall comprising at least one retention portion extending inwards there-from, the at least one retention portion is formed in the cap assembly before a piston is inserted into the open first end of the cap assembly;   providing a piston assembly, the piston assembly comprising the piston, the piston is configured for sliding movement within the air chamber as pressure in the connected plumbing system changes;   providing a base assembly, the base assembly comprising a base having an open end configured for connection with the open first end of the cap and a connector for connection with a pluming fixture in the plumbing system, the first open end of the base defining an exterior chamber therein surrounded by an interior sidewall, wherein extending through the base is a passageway fluidly interconnecting the first open end with the connector, the exterior chamber configured for receiving therein the open first end;   inserting the cap assembly, piston assembly, and base assembly into a high pressure chamber;   pressurizing the high pressure chamber;   inserting the piston into the open first end of the cap assembly and into the air chamber until the piston clears the retention portion thereby locking the piston inside the cap assembly;   inserting the open first end of the cap assembly into the open end; and   fixing the cap assembly to the base assembly.