Three screw including 3G three screw pump, 3GR three screw pump, 3GC marine-type three-screw and the special type. Three screw pump rotor type pump pit, because initiative driven screw screw with spiral grooves and their mutual engagement with the surface of the bushing with three holes, was able to import and export of three screw-level dynamic seal is formed between the number of chambers These dynamic seal chamber will keep the liquid from the pump inlet to pump outlet axial movement, and to gradually boost the transmission fluid, thereby forming a continuous, smooth, axial movement of the hydraulic fluid. Three screw pumps for a variety of body fluids containing solid particles, non-corrosive lubricating oils and oil-like liquid, viscosity of the fluid is 1.2 ~ 100OE (3.0 ~ 760cst), containing high viscosity liquids also by heating viscosity after delivery. flow range: 0.2 ~ 590m3 / h maximum working pressure of 100bar, maximum temperature 150 ℃ 1, three screw conveyor continuously conveying medium is linear, no mixing, no pulse. Two, three screw pump vibration and low noise. 3, three screw pump high pressure and high efficiency. 4, three screw pump, simple structure, easy disassembly. 5, three screw pump, small size, light weight. 6, three screw minor wear and long life. 7, three screw pumps are widely used in petroleum, chemical, metallurgy, machinery, electric power, machine tools, shipbuilding, glass, roads and other industries. 8, three screw pump for conveying fuel, lubricating oil, hydraulic oil, crude oil, asphalt and other similar liquid lubricating oils. 9, three screw pumps for lubrication in the industrial field, for the hydraulic pump in the hydraulic system, in the fuel system for transportation and booster pumps; in the oil system for the transportation and pumps. Flow range 0.2 ~ 600m3 / n maximum working pressure up to 6.3MPa.