just make sure there isn’t a lubricant in the valve, might be worth a call.
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Would you recommend this one for a 1lb setup?
As long as you are very certain that no other components will fail before the release pressure (140psi in this case) it should work just fine!
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The 3in hp clamps are rated at 800psi and the 1.5 ones are rated 1200psi. Sounds like I’ll be fine 
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How bout the sight glasses, that always seems to be a likely culprit
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I haven’t read the thread, I’ll be honest.
The biggest culprit in nitrogen assist machines is a bad operator. Butane will self regulate where it goes.
Nitrogen will not. I’ve known multiple labs where butane may have been the final cause of the explosion, nitrogen is what started it.
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Sight glasses! Yes.I’m sure thoes will be the first to go.
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Details would be helpful…I imagine.
The point of this thread is “how can I get this wrong?”
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Inserting nitrogen without attending, not replacing parts/keeping a log of when to replace parts, being careless when tightening the machine, not having enough valves to isolate the nitrogen if you get a clog.
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You da man
…
Manifold all that nitrogen to a single inlet header that ties into a check valve and “boom” all of a sudden you can’t hurt yourself.
It’s crazy how much of a difference a few well placed PRVs can make. Difference between overpressurizing on a daily basis to never even considering it an issue.
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What you’re proposing is definitely safer than not doing it, but check valves are not super reliable and can get stuck open if not taken care of. Also, the check valve doesn’t address the issue of what to do if the high pressure nitrogen already made it into the system with no where to go.
The proper code answer would be two-fold:
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2-step regulators at the N2 tank that reduce the supply pressure to a safe level. 2 step is required so that you can have redundancy in case one of them fails.
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PRVs on each vessel that are set according to the certified design pressure of the vessel (not operating pressures). PRVs are intended to keep vessels from exploding, not for regulating the pressure during normal operation. If you pop a PRV, technically it can no longer be considered fit for service until it’s recertified.
All this is from my memory working with BIG mainstream process vessels. IIRC the code makes exceptions for vessels below a certain size (which I’m pretty sure 99% of vessels in cannabis service are).
Consulting firms make a loooooooot of money telling refineries and chemical plants what kind of PRVs and where to put them to keep their shit up-to-code.
Source: Worked for one as my first job out of engineering school.
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Absolutely. This is why I said most issues are operators not understanding entirely what they’re doing.
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All very good points.
Aren’t there dedicated relief valves that can be hard piped to exhaust? An analogous situation from experience is the prvs on a boiler, they are typically exhausted to the roof.
Check valves can definitely be more dangerous than PRVs, I’ve misplaced a few in designs and immediately realized I had made a mistake.
What industry did you come from? Oil and gas?
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This potential danger seems to be the most overlooked, so I had to repost it. It isn’t as exciting as an explosion from over pressurizing, but can be just as deadly. Excess nitrogen can displace the air in a space, leading to suffocation.
This probably isn’t a huge risk in a well managed system, or a small system that doesn’t use much nitro, but it is a risk none the less. Most of the nitrogen will be contained in the cls until it is bled off, at which point venting it outside of the work area should be a priority, especially in a larger system ran in a small, enclosed space. Having a source of fresh air ventilation in the workspace will help keep safe.
The real danger of suffocation from nitrogen assist comes from any leaky tanks, valves, or lines that may be filling the environment with nitrogen unaware. Shouldn’t really be an issue if all is set up properly, but should still be kept in mind, as it wouldn’t be noticeable without monitoring.
Liquid nitrogen is much more of a worry in this sense, as it expands to gas at a ratio of 1:694. Not really a danger of nitrogen assist, but please keep this in mind if using liquid nitro for cooling.
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Not to derail too much, but have you SEEN the new precision LN2 beast? I’ve seen a few videos and the thing is just pouring out nitrogen gas. Scary.
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Just mix in some LOx and dont worry abooot it.
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Haven’t seen that yet, but sounds like one may want some beefy ventilation when running something like that! I’ll see if I can find one of the vids.
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Yeah it’s their Cryo-Cann system and I’d say it’s intended to be operated outdoors buuut they have a version that they’ve outfitted in a shipping container so…
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