摘要 |
A piston assembly 12 is provided. The piston assembly 12 comprises a reciprocating sleeve 14 incorporating an integral internal piston surface 28. The sleeve 14 is slidably mounted upon a cylinder head 18 so as to define a piston chamber 26 therewith, the piston chamber 26 being sealed in the vicinity of the cylinder head 18 by a circumferential static seal 20 that acts to seal against the reciprocating sleeve 14. The static seal 20 may occupy a horizontal plane and may include sacrificial wear zones and be formed from a graphite-based material. The piston assembly may be an over-square assembly for use in an oil-free environment for processing high temperature gases, for example, a hot gas engine or heat pump or heat engine such as may be used in an energy storage system. |