Patent ID: 8720648

Claim:
In a lubrication system for a natural gas compressor, in which a lubricant is intermittently injected into a compressor cylinder through a check valve that prevents natural gas from entering the lubrication system, the improvement comprising a protection device positioned between the compressor cylinder and the check valve to maintain an oil barrier to prevent natural gas from fouling the check valve, the protection device having a fill capacity of less than 1.966 cm 3 (0.12 cubic inches), the protection device further comprising: a first bore and a second bore cut into a solid plug having a threaded end for attaching to the compressor cylinder, the first bore leading to the compressor cylinder and the second bore intersecting transversely with a threaded third bore for attaching the check valve; and a fourth bore intersecting with and providing a connection between the first and second bores, the fourth bore being partially plugged to maintain lubricant within the device while allowing lubricant to flow between the first and second bores.