The oil-water separator filter is designed for oil - water liquid separation , containing two filters, namely: poly filter and separation filter. For example, in the oil in addition to the water system, oil flows into the coalescence separator, first passes through the coalescence filter, coalescence filter to filter out the solid impurities and tiny water droplets coalesce into larger drops. Most of the coalescence of water droplets can be separated and removed by gravity from the oil, the settlement into the sump. Then oil flowing through the separation filter, separation filter has good lipophilic hydrophobic, thereby further separating the water, finally the clean, dry oil outflow coalescence separator. Oil first inlet pipe into the lower portion of the filter housing, and then flows through the oil filter from the inside outward, when the coarse particles will immediately precipitated, and discharged by the drainvalve, the smaller particles are filter intercept. The after last clean oil through the filter tray pooled, from outlet pipe outflow coalescence separator, with the increase in the amount of oil to be processed, and deposited in the filter pollutants caused by the rise of pressure coalescence . Coalescence filter is clogged and should be replaced when the differential pressure rises to 0.15Mpa. Fluid from the coalescence separator inlet flow to a tray, and then internal shunt to a filter, filtered, demulsification, water molecules grew, coalescence process, impurities trapped in a filter element, the coalescent drops settlement in the settling tank, the oil from the outside into the secondary filter, br-inging together two trays from the coalescence separator outlet. Two filter material is hydrophobic, oil can pass free water were blocked outside the filter into the settling tank and discharged through the discharge of sewage valve.