High pressure plunger and method of manufacture

Claim 1

A high pressure plunger comprising a tubular member of cemented hard metal carbide, said tubular member having a length over diameter ratio of at least six to one, and having opposite ends, steel end caps abutting the opposite ends of said tubular member and each end cap having an axial portion engaging the inside of said tubular member adjacent the respective end cap, a rod-like portion on one of said end caps extending axially through said member with radial clearance and threadedly connected to the other end cap for interconnecting said end caps internally of said tubular member and holding said tubular member in a predetermined, compressively stressed condition, one of said end caps forming the rearward end of said plunger and the other end cap forming the forward end of said plunger, said rearward cap adapted for engagement to be driven linearly, a deformable metallic seal inerposed between said forward end cap and said tubular member sealing the internal region of said tubular member from the atmosphere surrounding the forward end of the plunger, and orifice means formed between the rear end cap and the tubular member connecting the internal region of the tubular member with the atmosphere surrounding the rear cap of the plunger.