INSTALLER-SEAL 2819276 - Caterpillar

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Typical example (1) Return oil manifold (2) Return oil filter (3) Hydraulic tank (4) Main pump drain oil screenThis section describes the construction and operation of the following return circuit components:
Return oil manifold
Return oil filter
Hydraulic oil cooler
Hydraulic tankReturn Oil Manifold
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(1) Return oil manifoldReturn oil from the main control valve goes to the return oil passage of the return oil manifold. Then, all of the return oil flows to the oil cooler and/or to the hydraulic tank through the return oil filter.Return oil enters the return oil manifold from the main control valve. The oil acts against the end of the 500 kPa (72 psi) check valve. Return oil remains blocked by the check valve until the pressure increases in order to overcome the check valve spring. The check valve maintains a constant pressure in the return line in order to prevent damage that is due to cavitation.Up to a pressure of 400 kPa (58 psi), the return oil from the control valve is sent to the oil cooler. When the pressure in the return circuit exceeds 500 kPa (72 psi) the check valve opens in order to allow flow to return to the hydraulic tank.Return oil from the swing motor or the pilot system is directly returned to the filter without back pressure.