Abstract: An accumulator comprises a cylinder formed with a substantially closed chamber and a piston formed with a small-diameter central region and a pair of large-diameter end regions flanking the central region and each formed with an outwardly open annular groove. This piston subdivides the chamber into a gas compartment at one of the end regions, a liquid compartment at the other end region, and an annular charging compartment surrounding the central region. The piston is displaceable in the cylinder to oppositely vary the volumes of the gas and liquid compartments. Respective gas and liquid seals are engaged in the grooves between the gas- and liquid-compartment end regions of the piston and the cylinder and are both constructed to inhibit fluid flow from the respective gas and liquid compartments into the charging compartment.

Abstract: Filament wound pressure tube has layers of filaments wound helically. The filaments of each such layer are disposed at an angle to a line parallel to the longitudinal axis of said tube which angle is approximately equal to a respective angle .theta. to the line, such angle .theta. being chosen such that the ratio sin.sup.2 .theta./r is approximately the same for all layers, where r is the radial distance from said axis to the location of such layer.