It is composed of a primary filter, oil pump, and press components. The primary filter is a cylindrical metal mesh, which can prevent the larger solid particles in the unqualified oil from entering the oil pump. The oil pump is usually a gear pump, which transports unqualified oil into the filter assembly for processing. The press component is a small hand-pressed oil filter unit, using special filter paper as the filter medium. 

The purifying hydraulic oil’s process is unqualified oil enters the plate and frame filter by the oil pump and passes through the filter paper, Then it becomes filter oil, which refers to the oil that is clean in appearance. The solid impurities in the oil are trapped on the surface of the filter paper, and a small amount of water is absorbed by the pores of the filter paper. The filtration press is normally less than 0.3Mpa. When there are too many impurities on the surface of the filter paper, and the filter pressure rises to 0.35Mpa, or when the water absorbed by the filter paper is close to saturation and the residual water in the filter oil no longer reduces, you should shut down the machine and replace the filer paper. When the oil has a high viscosity, it can be preheated to reduce the viscosity before filtering. This oil press- filter unit can only remove solid impurities and a small amount of water, and is suitable for the purification of ordinary electrical oil and smooth oil. If there are too much water and impurities in the oil, it must be pre-treated and then purified with a vacuum oil filter. The flow rate of an ordinary purifier machine(purifying hydraulic oil) is 25 to 200 liters per minute. The square filter frame installed for filtration has two inner side lengths of 200mm and 250mm. The filter plate and frame are made of cast iron or polypropylene.