Strengthened polypropylene filter plates and frame are made through mold pressing, high in strength, light in weight, corrosion resistant, non-poisonous and no smell; Adopt hydraulic pressing, with the maximum pressing pressure of 25 MPa, and automatic pressure maintaining by using electro connecting pressure gauge; Maximum filtration pressure: 1.0MPa for recessed plate type, 0.5MPa for plate and frame type to ensure optimum conditions for cake formation and pressure filtration; Simple in operation, convenient in maintenance, and safe in operation with multiple safety devices. Application: Solid-liquid separation in chemical, metallurgy, pharmaceutical, light industry, coal mining, foodstuff, textile, environmental protection, energy source and other industries