Patent ID: 7159508

Claim:
A sealing mechanism for a piston having a front head section with a front curved surface, a larger circular cross-section, a flat back surface and a smaller cylindrical rear head body, said piston moving axially in a tank cylinder having a circular cross-section that is slightly larger than the largest outer diameter of said piston head, said seal mechanism comprising: (1) a seal located on the back surface of said front head between said smaller rear head body and said tank cylinder, wherein said seal has an arcuate convex outer surface, an upper body, front and rear legs, an inner surface and an inner hollow area; (2) at least two annular stainless steel front leg rings located inside said front seal leg connected to said front leg and the flat back surface of said piston head by a nut and bolt; (3) a one-piece, T-shaped slidable annular rear tensioning ring slidably located around said rear head body and connected to the outside of the rear leg of said seal by a tensioning ring bolt and nut; (4) a tightening bolt having one end securely attached to said rear piston head body and the other end adjustably abutting against a tensioning spring; (5) a tensioning spring having one end abutting said tightening bolt and the other end abutting said tensioning ring bolt; (6) a stabilizing block having an essentially rectangular cross-section located inside of the inner hollow area of said seal; wherein the lower surface and lower part of said upper body has at least one inner groove cut therefrom; wherein the outer surface of said seal may be adjustably pushed in sealable contact with said cylinder body by turning said tightening bolt.