Used Nitrogen Generators for Sale
Nothing is listed right now — these are machines we've recently sold. or tell us what you need.
Recently sold
SOLDAtlas Copco Nitrogen Generator w/(2) Tanks, New in 2020
USA
SOLDAtlas Copco Nitrogen Generator w/(2) Tanks, New in 2020
USA
SOLD2007 Bauer Compressors SNG II Nitrogen Generation System
USA
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About Used Nitrogen Generators
A nitrogen generator splits nitrogen out of compressed air so a plant can blank a vessel, purge a package or feed a process without cylinders or a liquid tank. Two methods do it. A membrane lets oxygen pass and keeps nitrogen. Pressure-swing adsorption, PSA, uses beds that catch oxygen and switch. Atlas Copco is a name on these cabinets. The generator does not make compressed air. It needs a compressor, a dryer and filtration upstream, or the membrane and the beds die early.
Purity and flow are a pair. Higher purity, 99.5 percent and up for many blanketing jobs, costs flow. A generator that makes enough nitrogen at 95 percent may not make enough at 99.9 percent. Read both numbers at the pressure you will use. Inlet pressure has to match what your compressor delivers after the dryer. A membrane or a bed sized for 100 psi will not give the brochure flow at 80 psi. A receiver on the nitrogen side keeps the process from seeing every swing of the beds.
Filters, the dryer and the drain are part of the life of the machine. Oil or water in the feed air is how a membrane plugs. PSA beds have a life and a switching valve that has to move. A cabinet that alarms on purity and then keeps feeding bad gas is a control problem. Oxygen analyzers drift and need a calibration.
A used nitrogen generator should be run on dry, filtered air and checked with an analyzer, not only powered up. Read purity and flow at your pressure. Confirm whether the dryer and the filters are on the same skid or were left on the compressor. A membrane cartridge or a bed set is a consumable with a price. Match the purity the process needs before you match the size of the cabinet. Cylinders are still the right answer for a tiny, rare use. A generator earns its place when the process runs every day. Inlet dew point is on the same plate as purity. Wet air is the failure you can prevent.
How to Choose a Used Nitrogen Generator
How to Size a Nitrogen Generator
Start with the purity your process actually needs, then the flow at that purity. A looser purity makes more gas. A tighter purity cuts flow. Read both at the inlet pressure you can supply, because the generator does not create air. It splits the dry air you feed it. A dryer and filters belong upstream. Tanks on the outlet buffer the process. Atlas Copco is the name that repeats, as a membrane or a PSA cabinet. The compressor that makes the inlet air is a separate machine and often the larger motor. Match the generator to the spec, then confirm you have the air, the dryer and the tanks. Then stop.
Membrane Nitrogen or PSA Nitrogen
A membrane nitrogen generator pushes air through fibers and takes a nitrogen stream off one side. A PSA nitrogen generator swings pressure across a bead bed and adsorbs oxygen. Both want clean, dry inlet air, and neither one is a compressor. They are not parts you swap inside the same box. Purity and flow still trade off on either design. Tanks in the listing are a clue that the last plant buffered the outlet. A sold cabinet is still a useful size reference if the nameplate is readable. Pick the design your spec and your air supply can support, not the one with the fresher paint. Write the pair down.
Nitrogen Generator Specs to Compare
| Spec | Why it matters |
|---|---|
| Design | Both make nitrogen from air. They are not the same cabinet and not the same spare parts. |
| Purity and flow | More purity means less flow. A single headline number hides the trade. |
| Inlet air | The generator splits dry compressed air. Wet or low-pressure air will not make the rating. |
| Tanks | Outlet tanks buffer the process. Confirm they are in the listing. |
| Filters | A loaded filter looks like a failed generator. |
| Outlet pressure | The process has to accept the pressure the generator actually delivers. |
Design
Both make nitrogen from air. They are not the same cabinet and not the same spare parts.
Purity and flow
More purity means less flow. A single headline number hides the trade.
Inlet air
The generator splits dry compressed air. Wet or low-pressure air will not make the rating.
Tanks
Outlet tanks buffer the process. Confirm they are in the listing.
Filters
A loaded filter looks like a failed generator.
Outlet pressure
The process has to accept the pressure the generator actually delivers.
What to Inspect on a Used Nitrogen Generator
Read purity and flow
Both numbers, at a stated inlet pressure. Do not take one without the other.
Identify membrane or PSA
The design changes the spare parts. Confirm which cabinet you are looking at.
Check inlet filters
Loaded filters starve the generator. Budget elements with the cabinet.
See the tanks
Note whether receiver tanks are included. The process may need that buffer.
Confirm dryer air upstream
The generator wants dry air. The dryer and the compressor are separate machines.
Read outlet pressure
It will be lower than the air you feed in. Match it to the process.
Look at the nameplate
Atlas Copco is the repeating name. The plate still has to match your purity.
Related Equipment
- Air Compressors & Air Dryers
The inlet air a generator has to be fed
- Air Dryers
Dry the air before it reaches the generator
- Rotary Screw Compressors
Shop screws that can supply the inlet air
More in Plant & Material Handling
Nitrogen Generators Brands We've Sold
Common Applications
Frequently Asked Questions
What does a nitrogen generator need besides the cabinet?
Clean, dry compressed air at the inlet pressure on the plate, plus filtration, and usually tanks on the outlet. The generator does not make air. A membrane nitrogen unit or a PSA nitrogen unit only splits the air you feed it. Atlas Copco is the name that repeats on this group. The compressor and the dryer are other machines. A sold listing is still a fair way to see the size, as long as the nameplate shows purity and flow together.
How do purity and flow trade off?
Tighter purity means less flow from the same cabinet. A looser spec makes more gas. Read the pair at the inlet pressure you can actually supply. A brochure number at a different pressure will not match your header. Tanks buffer short peaks so you do not size only for the spike. If the process can live with a lower purity, you may not need a larger generator. Write the spec you need before you compare two plates.
Membrane or PSA for plant nitrogen?
A membrane pushes air through fibers. PSA swings pressure on a bead bed. Both want dry inlet air and both deliver nitrogen at a pressure below that inlet. They are not interchangeable insides. Pick from the purity and flow you need and from which design you can support with filters and spares. Atlas Copco cabinets of either type can appear here. The compressor that feeds them stays on the air compressor groups.
Why mention a nitrogen generator that already sold?
Because the group can be sold-out and the guide still has to describe the machine. A sold cabinet shows the purity, the flow and the tanks a plant actually ran. It is not a promise of current availability. When a generator is noted again, the same facts apply: inlet air, dryer, filters and outlet tanks. Inspect the nameplate and the filters. Do not treat a sold photo as a different kind of machine.
What should I inspect on the cabinet?
The nameplate for purity and flow, the inlet filters, the tanks if they are included, and whether it is membrane or PSA. A loaded filter can make a healthy unit look failed. Outlet pressure has to suit the process. Hours or alarms, if the panel shows them, are worth a photo. The compressor and dryer are not inside this box. Confirm you have dry air at the right pressure before you plan the install.
Is the air compressor included with the generator?
Do not assume it. The nitrogen generator is the membrane or PSA cabinet, sometimes with tanks. The screw compressor and the dryer that feed it are separate listings on the air groups. Voltage on the generator itself is often modest because the compressor is the large motor. Match the generator to purity and flow, then confirm the air supply can feed it. A cabinet without inlet air does not make nitrogen.
