Hoping the Aldeer knowledge will come to the help here. I need to provide very clean compressed air (a little over 100 psi) to open/close valves in a $300,000+ mass spectrometer. Obviously, I need reliability and no oil or water in the lines. Here are my 3 known options with pros and cons. I think the rate of maximum air usage would be around 100 psi/hr. This particular machine will be new to me so I don’t know all the ins and outs yet.

1) Renting 300 liter (I think?) industrial nitrogen cylinder.
Pros: cheap ($5.20 a cylinder). Plenty of pressure. Should be clean and possibly not need oil/water filters.
Cons: We might burn through a cylinder in 24 hours, which would make this a deal breaker.

2) Building compressed air (UA research building)
Pros: already in place so to speak. If the power goes out, should be large enough tanks to keep air flowing. Someone else maintains system
Cons: someone else maintains system. May not provide quite enough pressure (~95 psi), which could be a deal breaker. There is a history of huge amounts of water getting pushed through the lines and going right through light duty filters. Quote for heavy duty filtration system is $4500.

3) Buy our own oilfree compressor.
Pros: it’s under our control. Plenty of pressure. In theory clean air.
Cons: smaller tank may not last long if the power fails. Will take up limited space. Does oil free also mean free of water? How loud/quiet? How often would it need to kick on? We can drop a few grand on one if needed.

What other info do I need to consider? We will have the main system on a battery backup, but have not made plans to have a compressor backed up too (maybe we can?). I’m a geologist so not that knowledgeable about air compressors.

Cascade system would take care of periodic power loss. There are staged filtration systems available.

How long of a time period do you need to provide clean compressed air for this fancy machine? If you're wanting to keep the valves clean and dry I'd only recommend nitrogen.


Maybe look at spending some $$$ on a nitrogen generator if you need a long term option.

Why go cheap route on air when the machine is $300000?? I just ordered a $50000 air compressor to run a robot in a recycling facility. The robot cost $250000.

About 20 or so years.

Sounds like I'd go with a compressed air system with an air dryer and nitrogen generator.

And as far as whether the tanks last long enough to supply during a loss of power, have a UPS system installed with it.

From my much more intelligent than I son:


"The biggest question with the air isn't pressure, but rather volume in standard cubic feet per minute. If it's relatively low volume, the best option is either compressed nitrogen or breathing air from a cylinder provided by a contractor such a paxxair or whoever is local. Operating valves typically would not require much volume, so a rental cylinder may last weeks if not months. Getting the correct pressure regulator and having at least two cylinders set up in a cascade system so that they can be individually swapped is critical.

Compressors and filters are loud, require someone to maintain them, and will always be subject to power failure."

Kind of what I was thinking. A $4,500.00 filtration system is nothing when you’re talking about a $300k machine.

Check out the zero air generators. They supply clean oil free and water free air. Thats what we used for our instruments at Airgas. Cheaper in the long run than cylinders.

I would just get whatever size nitrogen tank you need. I see some labs with 1000 gallon tanks.

Right, but the engineers suppling the research equipment worry the building compressed air doesn’t have a high enough pressure to operate the system. I can spend 5k, but need that money to go to something that will do what we need. Trying to get some education on oilfree compressors. I don’t have 50k in this pot of money from which I can pull.

I can sell you a air filtration system that will
Fits your needs.

I’ll be back in the office next week.

Pm me your contact and I’ll send you a quote.

Harbour Freight a option?

I would definitely look for the 20% off coupon at HF.

The last compressor/dryer I supplied this year yet to be delivered was over 500,000, this comes with a electronic soft start not included. But, this is for a 6000 scfm machine for auto manufacturer which uses the hot discharge air of the final centrifugal stage to dry one of two dessicant bed towers to provide -20 degree dewpoint air at 125 psi @ 6000 scfm discharge. The flow is what is missing in your original post.

Roadkill's Son gets it...quote.."The biggest question with the air isn't pressure, but rather volume in standard cubic feet per minute. If it's relatively low volume, the best option is either compressed nitrogen or breathing air from a cylinder provided by a contractor such a paxxair or whoever is local. Operating valves typically would not require much volume, so a rental cylinder may last weeks if not months. Getting the correct pressure regulator and having at least two cylinders set up in a cascade system so that they can be individually swapped is critical.

I'll add that nitrogen is the cleanest available. You should be able to get flow requirements from the OEM of the equipment you are using. Take this information to Praxair, Linde, Air Liquide, Messer etc. which are all air separation companies. Messer would be my choice as they already have operations at the Nucor Plant in town there. They will lease or sell the receiver sized for the flow requirements and set you up on a regular route to keep supplied. The control system is standard instrument engineering standards on pressure control loops to include valve control. Its a small setup but, if you need help or do not have the expertise, I have an application engineer that can help you steer you in the right direction for piping size for proper flow and pressure delivery, it will cost you nothing unless you need schematics it would be minimal cost. Let me know and I'll hook you up, we have done projects for air attenuation for U of Miss etc..

Of course if all that is not required you can use coalescing filters in the compressed air system available if reliable. Not sure I would risk using the system at hand based on the cost and requirements of the new equipment. We could offer suggestions, shoot a pm if you want.