Packing for high pressure plunger type compressor - has non return valve in lubricating passage through packing cups

摘要

The compressor has a plunger (12) reciprocating within a cylinder (10). The working space is formed by packing cups (24, 25, 26) fitting round the plunger and held between end pieces (18) at the two ends of the cylinder. Each packing cup has an annular groove (32) on its inner surface on one axial face. A sealing strip (34) in this groove is clamped between the cup and the mating face of the next cup. Lubricating oil is supplied to the rubbing surface between the cups and the plunger through a passage (44) drilled axialy through the cups. A spring loaded ball non return valve (52) is built into this passage in one of the cups. This prevents the lubricating system being subjected to pressure variations from the working space.