Regarding vacuum pump selection
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We have a mixing tank with a capacity of 500 L. It is required that the oxygen level be below 10 PPM after vacuuming – what type of vacuum pump or vacuum system should be used? Currently, we are using rotary vane vacuum pumps, but once the vacuum level reaches the required standard, the oxygen content increases again within a day or two. The management says that the vacuum system is not effective; so what type of pump should we choose?
Has your vacuum unit been running continuously? A Roots vacuum pump can only compress gases; there must also be an exhaust pump. What is an exhaust pump?
After it’s qualified, you won’t stop the pump, right? If you do stop it, oxygen will continue to be released into the liquid or mixture inside. Of course, the oxygen level will rise again after a few days, unless you remove the oxygen from the mixture. I think a vacuum pump alone isn’t enough to do that; no matter what type of vacuum pump you use, it won’t work. I think the process needs to be modified.
Thank you for your reply. However, our gas mixtures are prepared by strictly deoxygenating them before mixing, so oxygen should not be released. Moreover, the oxygen content keeps increasing over time; it’s really hard to think of any possible reasons for this
Is there a flowchart? If the pump is working fine, it’s likely a problem with the system.
What kind of problems could there be with the system? Seal ring? Mechanical seal? I really don’t know much about machinery; it’s killing me
Don’t we have an exhaust pump? The evacuated gas was directly discharged into the return water pipe
Think about it: you’ve already managed to achieve a satisfactory level of vacuum. In a few days, the oxygen content will increase. If we rule out the possibility of oxygen being released from the materials themselves, then it must be that there’s a leak in your material storage container – the seal isn’t good enough. It’s not the vacuum pump’s fault; if the vacuum pump weren’t working properly, it would be impossible to achieve a satisfactory level of vacuum.
Our leader claims that there are dead corners in the material storage container; he believes that the pressure inside is positive, so outside air cannot get in
Do you carry out the reaction under vacuum conditions, or at normal pressure or under pressure? Even if the vacuum is properly established, air can still get in; leaks in flange seals, mechanical seals, etc., can cause this issue. If the reaction takes place at normal or positive pressure, could nitrogen be used to displace the air and maintain the pressure?
I also suspect there’s an issue with the mechanical seal, that the sealing isn’t proper, but our manager insists it’s a problem with the vacuum system