Which is better, the screw pump or the impeller pump, which is more durable ?

Which is better, the screw pump or the impeller pump, which is more durable ?

The characteristics of screw pumps are stable conveying medium, low turbulence of discharge medium, weak pressure pulsation, small mechanical vibration and low mechanical vibration. Low noise, the characteristics of the screw pump have self-priming performance, good suction performance, higher speed working capacity,  not sensitive to the viscosity of the medium.

It has the characteristics of simple and compact structure, the screw pumps are small in size, light in weight,  high efficiency, long life and easy operation,easy maintenance. Therefore, the screw pump has a wide range of uses. Comprehensive selection of various types of screw pumps, only in terms of the medium to be transported, its ability to transport various media exceeds that of all other pumps. For the same type of single screw pumps, their characteristics and application ranges are different.

The pressure of the screw pump is gradually established by increasing the pressure in the suction chamber through the sealing chambers at all levels to the pressure in the discharge chamber. The pressure builds up slowly. In addition to the advantage of low pulsation, the sound pressure level is also very low, and it has the advantage of ensuring that the conveying medium is intact and will not age quickly. Progressive cavity pumps are theoretically pulsation-free, since each rotation angle displaces the same volume of flow. In fact, there will still be some pulsations due to machining errors, gaps, and working lengths that are not integral multiples of the sealed cavity. But the pulsation of its discharge pressure is much smaller than other types of pumps. Pressure pulsation can cause vibration of the entire device, which is a very important cause of increased noise. Therefore, the important characteristic of small pressure pulsation also makes it superior to many types of pumps, so it is preferred in hydraulic systems and other systems.

Due to the fact that the screw pump has no valves and small pulsation, its hydraulic loss is small, so it is usually combined with mechanical friction loss and not calculated separately.

The advantage of the screw pump is that it can be self-priming, and there is no need to prime the pump when the pump starts to work. Wide range of conveying media. The disadvantage is that the pressure is low, the flow rate is small, and the bushing wears quickly. The advantages of impeller pumps (centrifugal pumps) are high pressure, large flow, and high efficiency. The disadvantage is that it cannot be self-priming, and can only transport clean water without impurities or liquids whose physical properties are similar to water.

Both impeller pumps and screw pumps have their own advantages.

• Working efficiency, the impeller water pump is generally higher than the screw water pump;

• The working pressure of the screw water pump is generally higher than that of the impeller water pump;

• The working flow rate of the impeller pump is generally higher than that of the screw pump.

• Work reliability, screw pumps are generally better than impeller pumps;

Impeller pump:  The working impeller drives the liquid to rotate at a high speed, and transmits mechanical energy to the liquid, so as to achieve the purpose of conveying the liquid. Impeller pumps are mainly used for pumping liquids with low viscosity. 

Impeller pumps include: centrifugal, mixed flow, axial flow, and vortex.

Screw water pump (screw pump): The screw pump is a positive displacement rotor pump, which sucks and discharges liquid depending on the volume change of the sealed chamber formed by the screw and the bushing. Screw pumps are divided into single screw pumps, double, three and five screw pumps according to the number of screws. 

Under the same technical conditions, screw pumps generally have higher volumetric efficiency than centrifugal pumps, 

so the motor power is relatively low, but screw pumps are generally more expensive than centrifugal pumps.

This depends on the customer's working conditions,  conveying material, flow rate and pressure to determine whether to use a deep well pump or a screw pump.