Patent ID: 7866153
Filing Date: 2011-01-11
Classification: F02G

Abstract:
1. A displacer piston assembly comprising a displacer dome, a displacer base, displacer piston rings and a displacer guide ring, in which said displacer dome and displacer base are held together by corresponding internal and external threads, in which the displacer dome has a shoulder (S 1 ) with length L 1 and diameter D and the displacer base has a shoulder S 2 with length L 2 and diameter D 2 , and the diameter D is approximately equal to the diameter D 2 , and in which the displacer guide ring is positioned between the shoulders S 1 and S 2 in which the lengths L 1 and L 2 are less than the length L 4 of the displacer guide ring.