The screw vacuum pump is a common vacuum pump that is often used in the industrial field.
It is recommended to add a valve between the screw vacuum pump and the pumped cavity, because most of the time the screw pump requires air/nitrogen/liquid purging, and the valve needs to be closed before purging to avoid purging. Air/nitrogen/liquid backflow into the vacuum chamber, breaking the vacuum or creating a bad situation.
What do we mean by “automatic purging”?
After adding the purging device, the relay has a delay before the system closes the Roots pump. At this time, close the valve before the pump and the cavity mentioned above, open the valve of the purging system, and the negative pressure in the pump will automatically purge the pump. The medium is sucked into the pump for purging, cleaning the pump cavity and prolonging the service time of the pump.
How can we know if the purge is complete?
If it is a very harsh environment, it is recommended to use a sewage bucket, and if it is relatively clean, a muffler can be used. There is a sewage outlet under the sewage barrel and the muffler. You can judge whether the sewage is completed by observing the cleanliness of the liquid coming out of the sewage outlet. In this way, after a few experiments, we will know how much time it takes to purge, and then set the purge time of the system according to this time.
If the medium is very clean, it can be directly purged with nitrogen or air.
If the pure ethanol vapor is pumped by the screw pump, then purging is not required; if the ethanol vapor contains other components, it means that the component can be dissolved in the ethanol vapor, then ethanol is used as the purging agent.
Circled in the figure below is the sewage drainage port, which is used for purging waste liquid discharge:
If the application is not for solvent recovery, simply place a bucket under this port to collect the waste through the purification system
If the customer’s application requires the recovery of the pumped gas, the valve has two options:
1.Close the valve when the pump is working, and open the valve when the purge system starts
B: Connect a pipeline from this valve to the recovery tank, keep this valve open, and recover some liquid through this valve