Patent ID: 8499983

Claim:
A tank comprising: a wall; a variable volume chamber containing a liquid and partially defined by the wall; a shaft within the variable volume chamber; a piston supported by the shaft for movement therealong within said tank along the wall under thrust from powder gas at a temperature much higher than that of said liquid in order to increase or decrease the volume of said chamber, the powder gas provided from a gas generator located at one end of the tank; and a deformable elastomer membrane that is attached to and movable with said piston and that comprises: a single membrane including an annular inner opening and an annular outer edge, the annular inner opening attached to and sealed to the piston at a position proximate to the shaft, the annular outer edge attached to and sealed to the wall of the tank at the one end of the tank proximate the gas generator, a first portion of the single membrane that is continuously pressed against an entire face of said piston outside said chamber, and a second portion of the single membrane extending from said first portion in a foldable form to the outer annular edge; said membrane, as attached, disposed to thermally protect said wall outside of said chamber between the one end of the tank and said piston, and to provide sealing between said piston and said wall.