Every cylinder of nitrogen that rolls into your shop on a delivery truck is mostly something you already own. Air is 78 percent nitrogen. You are paying a gas supplier, month after month, to separate, compress, and haul back to you the same molecules your compressor is already moving through the building.
A nitrogen generator ends that arrangement. It sits in your compressor room, takes ordinary compressed air in one side, and delivers nitrogen out the other, at the purity you pick, for as long as the compressor runs. Shops that cut with lasers, package food, mold plastics, or blanket tanks have been quietly switching from delivered gas to on-site generation for years, and the math is usually what convinces them.
How a nitrogen generator works
Air is a mix, roughly 78 percent nitrogen, 21 percent oxygen, and a little argon, CO2, and water vapor. A generator does not create nitrogen. It just removes everything else. Two technologies dominate, and they take different routes to the same destination.
Membrane generators
A membrane generator pushes compressed air through bundles of hollow polymer fibers. Oxygen, water vapor, and CO2 are what the industry calls fast gases. They slip through the fiber walls and vent away. Nitrogen is a slow gas, so it rides the length of the fiber and comes out the far end as product. No moving parts, no valves cycling, no noise beyond flowing air. Membrane units typically deliver purities from about 95 to 99.5 percent, which covers tire filling, fire system blanketing, and plenty of general inerting work.
PSA generators
Pressure swing adsorption uses two towers filled with carbon molecular sieve. Under pressure, the sieve grabs oxygen molecules while nitrogen passes through. Before the sieve saturates, the system swings: one tower depressurizes and dumps its captured oxygen while the other takes over. Back and forth, around the clock. PSA is the route to high purity, up to 99.999 percent and beyond, which is where food packaging, electronics soldering, and laser cutting live.
What purity do you actually need?
Purity is the whole game in nitrogen, and buying more nines than your application needs is the most common and most expensive mistake. Higher purity means more feed air, bigger equipment, and slower flow, so match the machine to the job.
| Application | Typical purity | Technology fit |
|---|---|---|
| Tire inflation | 93 to 97% | Membrane |
| Fire protection system blanketing | 98% | Membrane |
| Tank and pipeline inerting | 95 to 99% | Membrane or PSA |
| Food packaging (MAP) | 99 to 99.9% | PSA |
| Plastic injection molding | 97 to 99.9% | Membrane or PSA |
| Laser cutting assist gas | 99.99%+ | PSA |
| Electronics and reflow soldering | 99.99%+ | PSA |
Those figures are typical industry ranges. Your process spec wins every time, so check it before you size anything.
The part everyone underestimates: feed air
A nitrogen generator is only as good as the compressed air feeding it. Plan for two things.
First, quantity. It takes several cubic feet of compressed air to make one cubic foot of nitrogen, and the ratio climbs as purity climbs. A generator sized for high-purity laser assist gas can be one of the largest air consumers in the building. Before adding one, confirm your air compressor has the spare capacity, or budget for a dedicated machine. Undersized feed air is the number one cause of disappointing nitrogen systems.
Second, quality. Membrane fibers and carbon sieve beds are both ruined by oil and bulk water. Every generator wants a properly filtered, dry feed: coalescing air filters to strip oil aerosols, and an air dryer ahead of the inlet. Treat the feed air spec in the generator manual as a hard requirement, not a suggestion. Replacing a sieve bed because a filter element went unchanged for two years is an expensive way to learn this.
Does the math work for your shop?
Delivered nitrogen costs arrive in layers: the gas itself, cylinder or tank rental, delivery fees, and the labor of swapping bottles and managing inventory. On-site generation trades all of that for electricity, filter elements, and periodic service. For steady users, generated nitrogen commonly costs a fraction of delivered gas per cubic foot, and the equipment pays for itself over a few years of typical use. The heavier and steadier your consumption, the faster it pays back.
There are honest reasons to stay on cylinders too. If you use nitrogen a few times a month, or need very high pressure in small quantities, delivered gas keeps winning. The crossover point is steady, predictable demand.
One more benefit that never shows up on the invoice: you stop running out. No more idle line waiting on a gas delivery, no more juggling cylinder inventory ahead of a big job.
What we carry
We stock nano-purification equipment, including the NMG membrane nitrogen generator line, along with the filtration and drying gear that belongs upstream of it. The full nano purification collection covers generators, dryers, and filter elements. If you can tell us your required purity, flow, and pressure, we can help you land on the right size the first time.
Frequently Asked Questions
How pure is generated nitrogen compared to delivered nitrogen?
Delivered liquid-sourced nitrogen is typically 99.999 percent. A PSA generator can match that class of purity when specified for it. A membrane generator tops out around 99.5 percent, which is more than many applications need. The right question is what your process requires, not what the truck delivers.
How much compressed air does a nitrogen generator use?
It varies with purity and technology, but expect several CFM of feed air for every CFM of nitrogen produced, with the ratio rising sharply at higher purities. Always check the specific generator's air factor and confirm your compressor has that capacity to spare.
What maintenance does a nitrogen generator need?
Mostly feed air care: coalescing filter elements on schedule, dryer service, and periodic inspection. Membrane units have no moving parts. PSA units cycle valves that need attention over time. The sieve or membrane itself lasts many years when the feed air stays clean and dry.
Can I run a nitrogen generator off my existing shop compressor?
Often yes, if the compressor has spare capacity beyond current demand and the air is dried and filtered to the generator's spec. Meter your current usage first. If the compressor already runs near flat out, a dedicated feed compressor is the cleaner install.
If you are still writing checks for delivered gas, it is worth an afternoon to price out a nitrogen generator against a year of those invoices. For most steady users, the compressor room can simply take over the job.
