Theory of Operation
RETURN FILTER OPERATION
pressure surges in the return circuit and allows a path
The filter element (A) is located in a chamber inside
for return oil if the filter element becomes plugged.
the hydraulic oil tank. O-rings are used at each end of
During bypass operation, oil flows into the chamber
the filter element to prevent leakage. A spring holds
faster than it can flow through the filter element
the filter element on its seat.
causing the pressure to increase. The higher pressure
forces the bypass valve open allowing oil to flow down
Return oil from the oil cooler (D) and the control valve
the center of the filter element and into the hydraulic
(E) flow through the filter element from the outside to
oil tank. The bypass valve closes when the pressure
the center. Filtered oil flows out the bottom of filter into
decreases below the pressure setting of the bypass
the hydraulic oil tank.
A bypass valve (B) is located at the top of the filter.
The valve opens to protect the filter element against