Hydropneumatic piston accumulator and preparation method

The piston gas store has a cylindrical casing (10), inside which a piston (12) can move axially. The piston divides the casing cavity into a gas cavity (14) and a fluid cavity (16). The jacket surface of the piston has a fluid-receiving groove (18). The casing has at least one closable aperture (20). The groove is filled through the aperture. A preparation process is also described.