| 摘要 |
A piston unit (27) is movable forwards and backwards in the inner cylinder chambers (28) and is operable by means of a thrust rod. The inner cylinder (26) has top inlet apertures (32) for fluid intake to the upper part (29) of the cylinder chamber (28). At the bottom of the inner cylinder are outlet apertures (40) for outflow of fluid from a separate lower part (30) of the cylinder chamber to the outer cylinder chamber (41) and from there via a check valve (45) to a feed-out device for fluid. The piston unit (27) has at least one overflow channel and a valve mechanism which holds the overflow channel closed during the piston unit movement from the inlet apertures (33) to the outlet apertures (40). |
