Main relief valve keeps coming apart in manifold.

A meat processor has several meat dumping machines. The machines load a tub on a lift that would rotate up and tip, dumping meat into a grinder. The processor had problems with the meat sticking to the sides of the tub. The operator would cycle the lift at the top, “banging” it against a stop created by the cylinders bottoming out fully stroke. This helped force the meat to release.

They were having occasional problems with the Sun Hydraulics main relief valve that was screwed into a 2-bank valve manifold. The nose portion, where the tank flow exited the valve, was blowing off.   The valve appeared to be made in two pieces with a round key holding the nose into the main body.

Maintenance would clean out the manifold and the lines to the tank and replace the filter element. The crew would install a new valve, and everything would work well for a time. The firm tried to replace it with another brand but found it did not have a common DIN cavity porting, and they could not find another brand that would interchange. Maintenance also had a running battle with the operators, saying they were causing pressure spikes when they “banged” the lift to empty the tubs.

Any idea what was causing the problem?

See the Solution

• Main relief valve
• manifold