Before using screw pumps, we first need to have a clear understanding of what are the characteristics of screw pumps and screw pumps. In fact, screw pumps rely on interlocking space between screw and rubber stator (sealing line) to transport liquid. When the screw is rotated, the rubber stator at one end of the suction chamber (the sealing line) is continuously moved to the end of the cavity to make the volume of the suction inlet.

The pressure is reduced and the liquid enters the suction chamber along the suction tube under the pressure difference. With the rotation of the screw, the liquid in the sealing cavity moves continuously and uniformly along the axial direction to the discharge chamber. Because the volume of one end of the discharge chamber shrinks, the liquid is discharged. (see Figure 4-1)

The characteristics of screw pump are small flow and pressure pulsation, low noise, long life and self suction ability. It can be used as self priming pump product, and its structure is simple and compact.

The screw pump is also one of the rotor volume pump. The discharge pressure of the screw pump is determined by the total resistance of the pipe system connected to it. In order to prevent some reasons (for example, the discharge valve is not open), the resistance of the screw pump connection pipeline suddenly increases, so that the pressure of the pump can exceed the allowable value and damage the prime mover. The safety valve must be attached to the screw pump (see Figure 4-2), or other protective measures should be taken. In addition to single screw pump, the suction pipe must be configured for 40-80 mesh filter, filter, filter area is generally suction tube cross section 2 ~ 30 times, should be 

carefully removed from the filter to the pump suction welding slag, oxide and sand in the pipeline between the population, in order to avoid impurities into the pump, the screw pump "bite".