Displacement hydraulic cylinders are single acting extension only cylinders that are retracted using the load lifted and gravity. The cylinder is initially filled with hydraulic fluid in the area surrounding the piston rod when in its fully retracted state, when more fluid is then pumped into the cylinder it will displace the volume of the piston rod therefore forcing the piston rod to extend from the tube. The biggest difference between displacement and single acting cylinders is that unlike single acting cylinders there is no piston seal in a displacement cylinder. This means the force generated by a displacement cylinder is less than the force generated by a single acting cylinder of the same size as the force is calculated based on the area of the piston rod and not on the tube bore as it is for single acting cylinders. However, the displacement cylinder does remove the corrosion issues associated with single acting cylinders as no air breather is required.


  • Cost effective
  • Avoid corrosion in the tube bore as the cylinder is filled with oil


  • Only works in extension
  • Extension force is less than single acting cylinders of the same size
  • Less control than double acting cylinders
  • Limited range of hydraulic valves can be used with the cylinder
  • Requires external force to retract the cylinder