First, the characteristics of three screw pumps, including 3G universal, 3GC marine type and special type. Three-screw pump is a positive displacement pump, due to the active screw and the driven screw on the spiral groove intermeshing with the inner surface of the three holes with the bushing to pump between the import and export of several dynamic seal chamber, these Moving seal chamber will continue to move the liquid axially from the pump inlet to the pump outlet, and the infusion of liquid step by step to form a continuous, smooth, axial movement of the pressure liquid. Second, the scope of application of media and performance Three screw pump fluid is a variety of non-solid particles, non-corrosive oils and similar lubricants liquid, liquid viscosity of 1.2 ~ 100 ° E (3.0 ~ 760cst), High-viscosity liquids can also be viscosity-reduced by heating delivery. Flow range of 0.2 ~ 590m3 / h, the maximum working pressure of 100bar, the maximum temperature of 150 ℃. Third, the structure 1, simple structure: a variety of structural forms, the general small flow 0.2 ~ 6.5m3 / h, the pump pump and bushing together (collectively pump body), shaft seal for the mechanical seal. Medium flow pump bushing above is a separate part fixed in the pump body, large flow pump made of double suction structure horizontal installation, the shaft seal according to the different transmission media have mechanical seal and packing seal two. Marine pump installation in the form of horizontal and vertical two, the original motivation for the exchange, DC marine motor. 2, Long service life: The active screw of the three screw pump is driven by the motor. There is no mechanical contact between the main rod and the rod, and the pressure liquid is driven to rotate from the rod around the axis. The main rod, the rod, the screw rod and the liner There is a layer of oil film between the protection, so pump mechanical friction minimal life expectancy semi-permanent. 3, the infusion of liquid in the pump for axial uniform linear motion, so the pressure pulsation is small, stable flow, low noise, due to small rotating inertia, the starting torque and vibration is small. 4, with high suction capacity. 5, in order to ensure the safety of pumps, motors and piping systems, medium-volume screw pumps are equipped with safety valve above the pressure when the pressure exceeds the set pressure relief valve, high-pressure oil will return to the pump inlet.