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May 11, 2022 View:

The Difference Between Rotary Lobe Pump And Centrifugal Pump Screw Pump

There are many types of pumps, different pumps, their efficacy and characteristics are not the same. At present, the most widely used pumps in the domestic process pumps are: lobe pumps, centrifugal pumps, screw pumps, etc. So, what are the specific differences between the three? Today Ace will explain in detail.

I. Definition

1、lobe pump

The lobe pump, also known as a colloid pump, lobe pump, triple lobe pump or universal transfer pump, etc., is a volumetric pump. It conveys fluids by means of the cyclical transformation of several fixed volume delivery units in the working chamber.

lobe pump

2. Centrifugal pumps

The working principle of centrifugal pump is centrifugal movement, centrifugal pump work, high-speed rotation of the impeller blades drive the liquid rotation, the liquid will be thrown out, so as to achieve the purpose of conveying. Before the centrifugal pump works, the pump body and the inlet pipe must be full of liquid to form a vacuum state, when the impeller is rotating rapidly, the blade drives the liquid to rotate quickly, the rotating liquid flies away from the impeller under the action of centrifugal force, the liquid inside the pump is thrown out, the central part of the impeller forms a vacuum area, and the liquid outside is pressed into the inlet pipe through the pipe network under the action of atmospheric pressure. In this way the cycle does not cease, so that continuous conveying can be achieved.

lobe pump

3、Screw pumps

The screw pump is a new type of pump that works according to the principle of the great rotation mesh volume type, whose main working parts are the eccentric screw (rotor) and the fixed bushing (stator). Due to the special geometry of the stator and rotor, which form separate sealed chambers, the medium is evenly implemented in the axial direction, the internal flow velocity is low, the volume remains constant and the pressure is stable, thus no eddy currents and churning are generated. In addition, the stator of the screw pump is made of a variety of elastic materials, which gives it a clear advantage over other pumps in the transport of high viscosity fluids, media containing hard suspended particles or media containing fibres, so that screw pumps are widely used in sand and thick oil wells.

lobe pump

II. Distinctions

The difference between a lobe pump and a centrifugal pump

1, the lobe pump has a strong self-priming ability, while the centrifugal pump must be filled with liquid before moving to rotate.

2, the lobe pump is a volumetric pump, the delivery flow can be more accurately controlled, but also can be easily made into a variable pump. The output flow of the centrifugal pump cannot be controlled, and decreases with the increase of its own resistance.

3, lobe pumps can be easily made into varieties with higher output pressure, such as 15kg/cm2, suitable for long distance or high resistance quantitative conveying.

4, the lobe pump speed is very low, generally between 120rmp and 600rmp, the material being transported is smoothly output and its composition will not be damaged. The centrifugal pump's speed is very high, the material being conveyed is subjected to strong impact and centrifugal force, so the centrifugal pump often produces the phenomenon of inconsistent material composition when conveying the mixture, so that the quality of the finished product is reduced. The lobe pump is the best solution to this problem, so it is particularly suitable for conveying mixed materials and even materials containing solid particles.

5, lobe pump optimised rotor profile design, smooth pulsation, very small errors, very little vibration, high efficiency, which is also its biggest difference compared to centrifugal pumps.

6, lobe pumps can be used to transport very high viscosity substances, so also known as colloidal pumps. The centrifugal pump does not have this characteristic.

Difference between lobe pumps and screw pumps

1、The lobe pump can run dry, which is especially important in case of a sudden material break or operational error, preventing damage to the pump and ensuring safe operation.

2, lobe pump volume is small, is a single screw pump installation area of one-third, reduce the floor space and reduce costs.

3、The lobe pump can be conveniently maintained without dismantling the piping, which is convenient and flexible and reduces downtime.

4. The non-extruding working principle of the lobe pump and the adjustable design of the housing prolong the service life, reduce the number of maintenance and save the cost of spare parts.