Water hammer arrester

A water hammer arrester, said water hammer arrester configured for threading into a plumbing fixture, 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 exterior sidewall and a lower interior sidewall adjacent the open first end, wherein the lower interior sidewall comprising at least one retention portion, said retention portion extending inwards therefrom;
• a piston assembly, the piston assembly comprising a piston, the piston having a head and a tail, piston having an exterior surface defining at least one circumvolving channel configured for receiving therein at least one o-ring, the piston configured for sliding movement within the air chamber as pressure in the attached plumbing system changes, wherein between said at least one circumvolving channel and the head is a lock rim configured for locking against said at least one retention portion, and wherein a portion of said head is generally dome-shaped;
• and
• a base assembly, the base assembly comprising a base having a first open end and a second open end, said second open end comprising a threaded portion for threading into said plumbing fixture, the base defining an exterior chamber therein surrounded by a base assembly interior sidewall, extending through the base is a passageway for interconnecting the first open end with the second open end, said exterior chamber configured for receiving therein said cap assembly open first end, wherein said lower exterior sidewall can be fixed to said base assembly interior sidewall thereby encasing said piston assembly therein,
• wherein said piston is configured to be inserted into said cap assembly so that said lock rim passes said at least one retention portion, said at least one retention portion thereby holding said piston within said cap assembly.

A method of assembling a water hammer arrester, said water hammer arrester for attachment with a standard plumbing fitting, said method comprising the following steps:

• providing a piston assembly, the piston assembly comprising a piston;
• 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;
• providing a base assembly, the base assembly comprising a base having an open end and a threaded portion at an opposing end for threading into said standard plumbing fitting, the base defining an exterior chamber therein surrounded by an interior sidewall, extending through the base is a passageway for interconnecting the exterior chamber with a plumbing system the water hammer arrester is fluidly connected through use of the threaded portion connecting with a plumbing fitting;
• inserting said cap assembly, piston assembly, and base assembly into a high pressure chamber;
• pressurizing said high pressure chamber;
• inserting said piston into the open first end of said cap assembly and into said air chamber until the piston clears the retention portion thereby locking said piston inside said cap assembly;
• inserting the open first end of said cap assembly into the open end;
• and
• fixing said cap assembly to said base assembly, and
• wherein the at least one retention portion is formed in said cap assembly before said piston is inserted into said open first end of said cap assembly.

A water hammer arrester, said water hammer arrester configured for coupling with a plumbing fixture attached to a plumbing system, said 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 exterior sidewall and a lower interior sidewall adjacent the open first end, the cap comprising an exterior sidewall extending from said open first end to said closed second end, wherein said exterior sidewall has the same outside diameter from the open first end to adjacent the closed second end;
• and
• a piston assembly, the piston assembly comprising a piston, the piston configured for sliding movement within the air chamber as pressure in the attached plumbing system changes,
• wherein the lower interior sidewall of the cap comprises at least one retention portion extending inwards there-from, said retention portion configured for temporarily retaining said piston within said air chamber after said piston is inserted into said cap assembly but before a base assembly is fixed to said cap assembly.