Rapid retraction of Hydraulic Cylinder?

Question

Is it feasable to use compressed air to retract a hydraulic cylinder much faster than my small low volume pump will bring it back? I need full force of 30 ton on the forward stroke but it would only need less than 1 ton to bring it back. The actutor has a 6'' bore x 4' stroke and is extruding clay. If i set it up single acting it may jam on retraction. Steve

Answer 1

This should work. 120 psi probably gives a little under 2 tons, not counting pressure to push hydraulic oil back into tank.

There are various gizmos that speed it up; the air is probably your best bet. Some hydraulic cylinders don't like running on air; you should get enough fluid on the wall from the hydraulic stroke to lube everything OK.

The valving is a little tricky. Be careful not to trap the air and let it get compressed to high pressure on the extend stroke; really compressed air is dangerous.

If you connect a small compressed air tank to the retract side with no valve, and pressurize to say 50psi, should operate nicely as a single acting, though with some loss of speed and force on the extend stroke.