Selection and considerations of oil filters and their installation

Selection and considerations of oil filters, as well as knowledge of installation. Attention: When selecting an oil filter, the following points should be considered:

(1) The filtering accuracy should meet the predetermined requirements.
(2) Capable of maintaining sufficient flow capacity for a long period of time.
(3) The filter core has sufficient strength to prevent damage due to hydraulic pressure.
(4) The filter core has good corrosion resistance and can work continuously at the specified temperature.
(5) The filter core is easy to clean or replace. Therefore, the model of the oil filter should be selected based on the technical requirements of the hydraulic system, such as filtration accuracy, flow capacity, working pressure, oil viscosity, and working temperature.

2. There are usually several installation positions for oil filters in the hydraulic system:

(1) To be installed at the suction port of the pump: Surface type oil filters are generally installed on the suction path of the pump to filter out large impurities and particles to protect the hydraulic pump. In addition, the filtering capacity of the oil filter should be more than twice the pump flow rate, and the pressure loss should be less than 0.02MPa.
(2) Installed on the outlet oil circuit of the pump: The purpose of installing an oil filter here is to filter out pollutants that may invade components such as valves. Its filtration accuracy should be 10-15 μ m. And can withstand the working pressure and impact pressure on the oil circuit, with a pressure drop of less than 0.35MPa. At the same time, a safety valve should be installed to prevent clogging of the oil filter.
(3) Installed on the return oil path of the system: This installation plays an indirect filtering role. Generally, a back pressure valve is installed in parallel with the filter. When the filter is blocked and reaches a certain pressure value, the back pressure valve opens.
(4) Installed on the system branch oil circuit.
(5) Separate filtration system: Large hydraulic systems can be equipped with a dedicated hydraulic pump and oil filter to form an independent filtration circuit.

In addition to the oil filters required for the entire system, a dedicated fine oil filter is often installed separately in front of some important components (such as servo valves, precision throttle valves, etc.) in the hydraulic system to ensure their normal operation.