Screw Vacuum Pump Flowrate

For the performance of various vacuum pumps, there are prescribed test methods to test the pros and cons of their performance. The main performances are ultimate pressure, flow rate and pumping rate.

In this article, we will talk about the screw vacuum pump flow rate, such as how to control its flow rate, the reasons for insufficient flow rate and how we can eliminate this problem.    


Properly controlling the flow rate of the screw vacuum pump not only has a good protective effect on the equipment, but also can improve the utilization rate. So how to control it?  

  1. Speed control.

The change of impeller speed changes the flow curve of the screw vacuum pump, and the characteristics of the curve do not change. As the velocity decreases, the curve flattens and the head and flow rate decrease.  

  1. Bypass valve adjustment.

Use an intermediate valve and pump in parallel. The actual effect is like using a new pump system, which not only changes the larger output head of the screw vacuum pump, but also changes the flow curve characteristics, and the flow curve is more linear.  

  1. Adjust the impeller diameter of the screw vacuum pump.

No external components are used and the flow characteristic curve varies with diameter.  

  1. Adjustment of opening of outlet valve.

Using the intermediate pump and the outlet line regulating valve in series, the actual effect is like a new pump system, but does not change the larger output head of the screw vacuum pump, and the flow curve is attenuated.  


The reasons for the insufficient flow of the screw vacuum pump are mainly manifested in two aspects:  

  1. The pipeline leaks air and leaks liquid, and the resistance loss increases


Check the mechanical seal at the connection of the vacuum pump.

Check whether the pipeline and check valve are faulty.  


  1. Insufficient power supply of the motor leads to insufficient rotation speed, insufficient water supply, excessive clearance between the impeller and the distribution plate, damage to the mechanical seal, resulting in water leakage and air leakage, excessive wear of the impeller, and the circulating water cannot be discharged.  


Check whether the power supply voltage of the vacuum pump is within the rated voltage range of the motor.

Increase the water supply (must be controlled within the correct range, otherwise it will cause the motor to overload and heat).

Adjust the gap between the impeller and the distribution plate (generally 0.15-0.20mm).

Replace the mechanical seal.

Replace the impeller.

Check the pipeline of the water outlet.  


The reason why we want to talk about the flow rate of the screw vacuum pump is to make the vacuum pump cope with various tasks in a better state, so that it will not affect the efficiency of the vacuum pump.


If you want to learn more news about screw vacuum pumps, please read these blog posts.



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