Sealing system or Stirling gas engine for cryogenerator - has upper dry sealing piston ring in addition to normal split metal rings

摘要

Near the top of the piston a 'dry' polymer piston ring (5) is set in a groove (8) in the piston wall. The ring is continuous and is under radial pressure from the metal spring (6). Halfway down the piston two conventional 'split ring' oil rings are set into grooves. At the lower end of the piston a conventional 'scraper ring' (10) is in contact with the cylinder wall. Circular grooves (11, 12) are let into the cylinder wall (2) and the piston wall (1), between the upper and middle rings, in such a way that part of the groove in the cylinder wall is always opposite part of the groove in the piston wall.