Function

The main function of hydraulic filter is to protect the normal operation of hydraulic components and extend their life.  By filtering impurities in the oil, the hydraulic filter ensures the cleanliness of the hydraulic system, thereby avoiding wear and damage to the hydraulic components caused by impurities.

Types

Hydraulic filter according to the filter material filtration mechanism, mainly divided into the following types:

Surface type filter: such as mesh filter and wire clearance filter.  The filtration function of this type of filter is mainly realized by the geometry of the filter element.  The mesh filter is composed of copper wire mesh wrapped on the core frame, and the filtration accuracy is related to the mesh size and the number of mesh layers.  The wire gap filter is composed of metal wire wound on the core frame, and the small gap between the lines is used to block the passage of particles.
Depth filter: The filter element is composed of porous permeable materials, such as paper, felt, sintered metal, ceramics, various fiber products, etc.  The filtration effect of this type of filter occurs in the internal channel of the filter core material, the particles larger than the surface aperture are trapped on the outer surface, and the smaller particles enter the inside of the material and are absorbed by the channel wall.
Adsorption filter: such as magnetic filter, made of permanent magnets, can absorb iron filings, iron powder or magnetic abrasives in the oil.

Installation position and function

The installation position of the hydraulic filter in the hydraulic system has a great influence on its pollution control effect.  Common installation locations include:

Oil suction filter: In order to prevent pollutants from entering the pump, the oil suction filter is generally installed in the oil suction port or the oil suction pipe.  The suction filter is submerged at the bottom of the tank, so mesh or wire gap filters are often used without a housing.
Pressure line filter: The filter installed in the pressure oil circuit is mainly used to protect the downstream hydraulic components of the pump.  As the main filter of the system, its filtration accuracy should be able to ensure the system's requirements for oil cleanliness.
Oil return filter: Install a filter in the system oil return circuit to remove particulate contaminants that enter the system and are generated within the system.  However, because the flow pulsation caused by the hydraulic motor and hydraulic cylinder in the return oil circuit will reduce the filtration performance of the filter, the return oil circuit filtration is usually only in the case of relatively stable system to achieve the desired effect.