Screw pump It is a kind of positive displacement pump. It is a positive displacement rotor pump that transports liquid by changing the volume between several meshing screws. According to the number of screws operating at the same time, screw pumps can generally be divided into single screw pumps and multiple screw pumps (twin screw, three screw, five screw, etc.).

One or more sealing spaces will be separated between the suction inlet and discharge port of the pump due to the engagement of the screws and the close fit between the screws and the inner wall of the bushing. With the rotation and engagement of the screw, these sealing spaces are constantly formed at the suction end of the pump, sealing the liquid in the suction chamber, and moving from the suction chamber to the discharge end along the axial direction of the screw, sealing the liquid in each space. The liquid is discharged continuously, just like the nut is pushed forward continuously when the thread rotates, which is the basic operating principle of the screw pump.

　　 Three screw pump The sealing chamber is composed of an automatic screw, two driven screws and a bushing containing three screws. The liquid in the cavity moves axially with the rotation of the screw rod to achieve the purpose of transporting liquid. The special structure of the pump ensures that the master and slave rods are not affected by the radial force. The axial force is hydraulically balanced. The bearing only bears the dead weight of the screw and a small residual axial force. Several dimensions of the screw can ensure that no torque is transferred from the master rod to the slave rod. The driven rod rotates under the pressure of transporting liquid, ensuring long service life and high mechanical power of the three screw. It has high volume power.

Three screw pump is commonly used as auxiliary pump for oil depot and pump station to transport lubricating oil and medium viscosity crude oil. Double suction horizontal three screw pump for oil-gas mixed transportation is widely used for oil-gas gathering and transportation in various oilfields.