0175// Gas Ballasting by Nitrogen
In this post, we will discussing how gas ballasting work for low vacuum pump and what is the advantages to having gas ballasting and what is the disadvantage for it.
Gas ballasting also known as purging by some high vacuum professionals. Due to normally people tend to use nitrogen gas as ballasting gas, some of them also call it "nitrogen purge".
How it work?
Gas ballasting work by leverage the phenomena as described in Dalton's Law to reduce the condensation of water vapor in pump oil, especially rotary vane valve.
By introducing inert gas such as nitrogen gas (please! Don't use light gas like Helium, even we know that, Helium is inert. Because you may trap your helium somewhere in your pump) during pump compression phase.
With same pressure create by pump during compression phase, this can suppress partial pressure of water by increase partial pressure of nitrogen gas to avoid it condenses in your pump oil.
Benefits
This can minimize the water contamination in your pump (symptoms of water contamination: oil become milky)
Some professional also argue that, this can help to "clean" helium which may trap inside your pump during helium leak check
Disadvantages
Since your pump need to work harder to pump ballasting gas. This may decreasing your pump performance.
Return 0;
