(1)Plunger hydraulic cylinders are single acting hydraulic cylinders, hydraulic pressure can only achieve movement in one direction, or plunger piston return to other external forces of weight;

(2) piston cylinder sleeve not only contact with the cylinder, cylinder is easily processed, it is suitable for long-stroke hydraulic cylinder;

(3) work plunger is always under pressure, so it must have sufficient rigidity;

(4) the piston weight is often large, horizontally prone to sagging due to weight, resulting in sealing and guiding uneven wear, so the vertical using the more favourable.

Only one-way motion of the piston, its movement in the opposite direction to be done by external forces. But his itinerary is piston hydraulic cylinders.