Lafayette 3606 Engine VTJ5600 - Caterpillar

Illustration 1 g03650316
(1) Return filters
(2) Hydraulic oil tankThe return system utilizes two return filters. Return filters (1) are located on top of hydraulic oil tank (2). Oil that flows to the return filters is combined oil from both anti-cavitation manifolds.
Illustration 2 g03650339
(3) Inlet port
(4) Spring
(5) Bypass spring
(6) Filter element
(7) Housing
(8) Passage
(9) Outlet portThe return filters for the hydraulic tank are equipped with a bypass valve. The bypass valve is closed until the return line pressure exceeds 241 kPa (35 psi). The IQAN system monitors the bypass valve and alerts the operator when the valve is open via a message displayed on the operator monitor.During normal operation, return oil enters inlet port (3), flows through filter element (6) to passage (8), and into the hydraulic oil tank through outlet port (9).When the temperature of the return oil in inlet port (3) is low, the viscosity of the oil is high. The flow resistance through filter element (6) is high. Thus, the pressure of the return oil is high.As a result of the high pressure of the return oil, bypass spring (5) will compress allowing oil to bypass filter element (6). Most of the return oil flows through the bypass to passage (8) and exits outlet port (9) to the hydraulic tank.As the oil temperature increases, the return oil pressure decreases. The bypass check valve will begin to close as bypass spring (5) forces the valve to close.