Abstract: A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

Abstract: A sealing device arranged to provide the seal for a fluid, in particular a liquid, between an ambient and the inside of a cavity comprised between a stationary member and a rotating member is described.The main feature of this sealing device is that it comprises two annular sealing elements, each of which has a plane annular surface substantially orthogonal to the axis of rotation of the rotating member and a cylindrical side surface orthogonal to the said plane annular surface, one of the said sealing elements being rigidly connected to the stationary member and the other to the rotating member, the said two plane annular surfaces being coupled and axial thrust means being provided which are arranged to keep coupled the said plane annular surfaces with a predetermined pressure, the said two cylindrical side surfaces of the two sealing elements having the same diameter and being substantially coincident.

Abstract: A two part sleeve gasket is provided for sealing between a pipe and a hole receiving the pipe, such as a porthole in a manhole. The gasket includes a first annular element of resilient elastomeric material having a generally tubular body portion and an outwardly, reflexly curved flange radially spaced therefrom. The flange is generally tubular and shorter in length than the body portion. A second annular element resembling an O-ring of elastomeric material surrounds the body portion in the radial space defined by the flange, the flange being radially flexible into engagement with the wall of the hole and the second annular element being elastically deformable upon being radially compressed between the flange and the body portion. The invention also comprehends the method of installing the aforesaid gasket.