Nitrogen push purge question


Do I need to purge the nitrogen out of my collection base before I turn on my recovery pumps on to recover? Is it safe for recovery pumps to be sucking in nitrogen? Is the nitrogen comprising the seals in anyway? I do purge the nitrogen out of my solvent tank after I push the solvent to my column. While my column is dripping into my collection base I start recovering. The residual nitrogen really helps push the solvent from my column into the collection base. I purge my recovery tank periodically when the psi hits above 50psi. Ever since I started using nitrogen, I have had to rebuild three top end with in 2 weeks. Is this just my luck or something that I should be doing that I am not.

I am using 2 CMEP

Thanks in advance for the help and guidance.

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I am unfortunately not sure if N2 can damage your recovery pumps. I am in a similar situation, but I have the ability to inject into and vent my material column. I am curious, do you only inject N2 in your solvent tank, or do you inject at the top of your material column as well? If you only inject into your solvent tank, then is any N2 actually getting into your material column? I’d think the N2 gas would stay in the head space of your solvent tank, although if you start your recovery pump while introducing N2 I could see some bubbles getting sucked through the dip tube and into your material column but that is pure speculation. Welcome to the forum btw!

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youll be fine with the n2 going through the pump, its just a gas like the butane gas you are recovering with the pump. I would dump the n2 gas after inject if you can, otherwise recovery will take longer and you will end up with lots of n2 in your tank resulting in extreme pressures once the solvent tank warms back up. We reuse the n2 in our system, but it was volumetrically designed to do so.

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Hey if you are running an active system, you could give warm vapor assist a try if you’re having issues with nitrogen.

With warm vapor there is no need to randomly (and dangerously) vent your solvent tank/system as you can be certain the only thing inside is solvent.

I’m not sure what to say about why you’re having to do so many rebuilds on your CMEPs. Three rebuilds in two weeks sounds excessive for sure.

Can you explain how to use warm vapor assist with live resin runs properly in a way that doesn’t contaminate the end product?

hot loop the tank with the pump, use a inject coil packed in dryice to bring the solvent temp down before it enters the material column.


After inject do you mean into collection or into the material column?

Ususaly people will inject through the material column into the collection, chill the collection and bleed off the n2.

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In this situation, I’ve seen on other parts of the forum people will bleed off the N2 to slightly above 0PSI, then recover. I saw one person say between 1 and 5 PSI. Is it of concern to have that 1-5 PSI of N2 in the system for recovery?

Ultimately I guess I’m concerned about recovering ANY N2 into the recovery tank. Is there a way to bleed ALL of it? Perhaps with a one-way valve, at the low 1-5 PSI begin to heat the collection pot until I see some solvent fumes leaving the recovery vessel? Will the N2 completely leave the collection pot with a 1 way valve since it has lower specific gravity than air? or would that only be the case in atmospheric conditions?

N2 is an inert gas and will stay a gas in your recovery tank. It does no harm other than added pressure which should be vented off safely. Otherwise there is absolutely zero reason to worry about nitrogen in your recovery tank or any tank tbh


sweet, so basically just keep an eye on the pressure in my tanks and if it gets too high I can get the tank cold and release the pressure to a lower psi that way. Legit. thank you!!

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my pump goes to 500 psi, I dont want that shit anywhere near my system. purge it before the pump. it doesnt go down in pressure like hydrocarbons. just get it out instead of moving it into your tanks. Yes youll lose some gas, yes you should do it in a safe manner exhausting outdoors but if you use nitrogen you should purge it out instead of pushing it into another tank.

idk what pump you’re talking about. if you’re talking about an active system, I know nothing about them, I run passive. Regardless, I meant after I reduce the pressure in my collection vessel and recover multiple times, I would release any pressure my tank has below my solvent’s boiling point.

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Would it be fine to attach an air compresor silencer filter to the end of my bleed off hose to keep noise down? I know the n2 would be okay but how about butane/propane would the added pressure from the filter be something to worry about running fully outdoors???

Not sure about passive but active systems it will also start to reduce the efficiency of the pump= slower recovery speeds. Depends on the ratings of your specific pump, but for example as the MVP 6cfm reaches around 50psi head pressure recovery speed starts to crawl to a near stop.

I can only assume the same is true of passive systems as well, as pressure equalizing between the solvent tank and collection would result in no movement

gets tougher when using a gas mix but its easy to get butane below boiling.