330F MHPU Mobile Hydraulic Power Unit Machine System Caterpillar

Illustration 1	g03201665
(1) Return filter (2) Element (3) Return chamber (4) Tank chamber (5) Suction filter (6) Suction port (7) Passage (8) Relief valve (9) Return port (10) Passage (11) Hydraulic tank (12) Air breather

The return oil from the hydraulic oil cooler flows through return port (9) and passage (10) to return chamber (3).

Return filter (1) consists of element (2) and relief valve (8). The return filter is internally mounted in the hydraulic tank.

The return oil passes through element (2) of return filter (1). The return oil then flows through passage (7) in hydraulic tank (11). Thereafter, the oil passes through suction filter (5) and the oil is delivered to the pumps through suction port (6).

Air breather (12) is located on the upper surface of the hydraulic tank. The air breather prevents an increase or a decrease of air pressure in the hydraulic tank regardless of the following circumstances:

• Change of air pressure in the hydraulic tank due to cylinder movement.

• Change of air pressure in the hydraulic tank capacity due to a temperature change.