Plate and frame oil filter is composed of primary filter, oil pump and filter device. The primary filter of plate and frame oil filter is a cylindrical metal mesh, which prevents large solid particles in impure oil from entering the oil pump. The oil pump of plate and frame oil filter is usually a gear pump, which transports impure oil into the filter device. The filter device of plate and frame oil filter is a small manually pressed plate and frame filter press, using special filter paper as filter medium. Impure oil enters the plate and frame filter press under the pressure of the oil pump, and becomes filtered oil after passing through the filter paper. Solid impurities in the oil are trapped on the surface of the filter paper, and a small amount of water is absorbed by the capillary pores of the filter paper. The filtration pressure is usually not more than 0.3 MPa. When too much impurities deposit on the surface of the filter paper and the filtration pressure rises to 0.35 MPa, or when the water absorbed by the filter paper is nearly saturated and the residual water in the filtered oil no longer decreases, the filter paper should be replaced after shutdown. When the oil viscosity is high, it can be preheated to reduce viscosity before filtration. This type of plate and frame oil filter can only remove solid impurities and a small amount of water, and is suitable for purification of general electrical oil and lubricating oil. When the oil contains too much water and impurities, it must be pretreated before being sent to the oil filter. The processing capacity of plate and frame oil filter is 25~200 L/min. The square filter frames of the filter device have two inner side lengths: 200 mm and 250 mm. The filter plates and frames are made of cast iron or polypropylene.
