Hydraulic device especially a hydropneumatic accumulator

A hydropneumatic accumulator comprising a cylinder, a piston freely axially displaceable within said cylinder and dividing said cylinder into a hydraulic fluid chamber and a gas chamber at opposite ends of said piston, an end wall closing the end of the cylinder adjacent said hydraulic fluid chamber, an inlet part through said end wall for hydraulic fluid, a first sealing member in said hydraulic fluid chamber adapted for axial displacement with respect to said piston, means to limit said axial displacement of said first sealing member, a second sealing member cooperatively associated with said first sealing member for providing relative axial displacement between said sealing members and a flow channel between said inlet part and said hydraulic fluid chamber, and seal means between said first and second sealing members to permit flow of hydraulic fluid through said channel from said inlet part to said hydraulic fluid chamber, and to prevent backflow of hydraulic fluid from said hydraulic fluid chamber to said inlet part when the pressure on the hydraulic fluid chamber side of said seal exceeds the inlet pressure.