Sealing device with thermal expansion pressure accumulator

Claim 1

For adequately but not excessively pressurizing an annulus of fluid viscous plastic sealant material that is received, confined and held compressed in an annular pocket coaxially between the outer periphery of a surrounded, inner metal part and the inner periphery of a surrounding, outer metal part, a thermal expansion pressure accumulator comprising: housing means providing a cylinder; a piston sealingly slidingly received in the cylinder to provide a sealant reservoir chamber within the cylinder between one end of the piston and one end of the cylinder; means providing a fluid passage for communicating the sealant reservoir chamber with the annulus of fluid viscous plastic sealant material; said reservoir chamber and fluid passage being adapted to be filled with fluid viscous plastic sealant material in communication with said annulus; and compressible variable force means in operative contact with the opposite end of said piston so that, in use, as the pressure on said sealant tends to build up, said piston tends to retract in said cylinder and to correspondingly compress said compressible variable force means, and as the pressure on said sealant tends to fall, said compressible variable force means tends to extend said piston in said cylinder to apply more pressure to said sealant.