Hydraulic pressure relief valve and fluid isolator

Claim 1

A hydraulic pressure release valve and isolator, comprising: (a) a body, having a passageway extending completely through said body, (b) a flexible diaphram secured to said body within said passageway and extending completely across said passageway in a generally transversal direction to prevent flow through said passageway, (c) a port extending from the outside of said body to said passageway, located to one side of said diaphram, (d) means for closing said port below a specified pressure within said port and removing said closure above said specified pressure, said body being fabricated of electrically insulating material and further comprises a threaded end about one end of said passageway to accept a sensing device and a hollow conical projection at the other end of said passageway to accept a flexible tube, said conical projection being located on the same side of said diaphram as said port to transmit pressure from within a tube connected to said conical portion through said diaphram to said sensing device, said means for closing said port is an "O" ring of resilient material surrounding said body and covering said port, and said body contains a first groove encircling the body and passing through the opening of said port to hold said "O" ring in place over said port opening and said body contains a second groove encircling the body adjacent said first groove to hold said "O" ring away from said port and thereby uncover said port.