Nitrogen Generators for Laboratory Gas Supply
Your LC-MS, your GC and your sample-prep evaporators all draw nitrogen, and every one of them stops when a cylinder runs empty. NITROBERG® generators produce that nitrogen on your own site, from compressed air, at grades from 97 % up to 99.999 %. A nitrogen generator for laboratory use is sized either for a single analyser or for a whole floor that keeps adding instruments.
What a laboratory nitrogen generator has to deliver
Nitrogen is not one requirement in a laboratory, it is several. An LC-MS (liquid chromatography with mass spectrometry) draws continuously as nebuliser, drying and curtain gas, and it draws for as long as the sequence runs. Blowdown evaporators and sample-prep stations typically pull the largest volumes, usually in bursts. Gas chromatographs (GC), ICP-MS systems (inductively coupled plasma mass spectrometry) and thermogravimetric analysers (TGA) pull far less, but they set the purity everyone else has to live with. Gloveboxes, multigas incubators and blanketed sample storage sit somewhere between the two.
That mix is what makes gas supply a planning question rather than an equipment question. Demand grows every time a new analyser arrives, and cylinders run out at the least convenient point in a sequence.
A laboratory nitrogen generator answers that by separating nitrogen from compressed air on site. In a PSA system the air passes through a bed of carbon molecular sieve, which takes up oxygen, carbon dioxide and residual moisture far faster than it takes up nitrogen; a second bed regenerates at lower pressure while the first one produces, so output stays continuous. The PSA nitrogen generator page covers the process in detail, and the carbon molecular sieve article explains why the sieve is the component that determines what the machine can actually reach.
Which laboratory instruments need which nitrogen purity
Purity is where lab gas planning usually goes wrong, in both directions. Specify too low and a detector drifts. Specify too high across the board and you pay for it in compressed air every hour the plant runs. The table below gives the grades these instruments typically call for, and whether they drive your volume or your purity. Always confirm against the specification of the instrument you actually own, because requirements differ between manufacturers and detector types.
| Instrument | Typical grade | What the nitrogen does | Drives |
|---|---|---|---|
| LC-MS | 99 % to 99.5 % | Nebuliser, drying and curtain gas | Volume |
| GC with FID (flame ionisation) | 99.999 % | Carrier and make-up gas | Purity |
| GC with ECD (electron capture) | 99.999 % and above | Carrier gas for an oxygen-sensitive detector | Purity |
| GC-MS | 99.999 % | Carrier gas | Purity |
| ICP-MS | 99.999 % | Collision and reaction gas, auxiliary gas | Purity |
| TGA | 99.999 % | Inert atmosphere in the balance chamber | Purity |
| Blowdown evaporators, sample prep | 95 % to 99 % | Solvent removal | Volume |
| Glovebox | 99.99 % and above | Protective atmosphere | Purity |
| Multigas incubator | 99.5 % | Displacing oxygen to a set concentration | Neither, low draw |
| Blanketed sample storage | 99.5 % | Headspace protection for standards and reagents | Neither, low draw |
Read the table by column, not by row. Your volume comes from the instruments in the volume column, your purity grade comes from the single most demanding entry in the purity column.
What higher purity costs in compressed air
Every NITROBERG® size consumes a defined amount of compressed air per cubic metre of nitrogen it delivers. That ratio, the air factor, is identical across the range and depends only on the purity you set.
| Purity | 97 % | 98 % | 99 % | 99.5 % | 99.9 % | 99.99 % | 99.995 % | 99.999 % |
|---|---|---|---|---|---|---|---|---|
| Air factor | 2.3 | 2.3 | 2.6 | 2.9 | 3.4 | 4.6 | 5.2 | 6.4 |
Moving from 99.9 % to 99.999 % nearly doubles the compressed air needed for the same cubic metre of nitrogen, and compressed air is the energy bill. A laboratory that only runs evaporators and blanketing pays roughly twice as much per cubic metre at grade 5.0 as it would at 99.9 %, for gas quality no instrument on the bench can use.
This is also the reason a single central supply is not automatically the right answer: one source can only run at one purity. Put a GC with an ECD on the same supply as your evaporators, and the evaporators run at air factor 6.4 as well.
How to size a nitrogen generator for your lab
List your instruments and their draw
Take the consumption figure from each instrument manual, in litres per minute. Estimates from memory are the most common source of an undersized system.
Set the purity
Take the highest requirement on your list from the table above, then confirm it against the specification of the instrument itself.
Add simultaneity and headroom
Decide which instruments genuinely run at the same time, then add capacity for the analyser you will buy next. Gas supply is usually the last thing anyone plans for when a new instrument arrives.
Check what that means for compressed air
Multiply your nitrogen figure by the air factor for your chosen purity. If you already have a compressed air network with sufficient capacity and quality, the generator connects to it. If you do not, a skid-mounted package brings its own compressor, treatment, storage and control.
Need sizing for your application?
Send us your consumption profile and operating data. Our engineering team will size the generator and confirm the configuration.
One nitrogen generator, or one per instrument?
Laboratories usually arrive at central supply by accident. A laboratory gas generator is bought for the first LC-MS, another one for the GC bench, a third when the second mass spec lands. At some point there are four or five machines to service, four or five sets of filters to stock and four or five things making noise in a room that was never designed for them.
Consolidating onto one larger unit changes that: one service visit instead of several, one set of wear parts, and the generator can sit in a plant room instead of taking bench space and adding sound to the laboratory itself. For the same total capacity and comparable equipment, one unit is usually the cheaper route, and capacity can be added later as the instrument count grows.
It is not automatically the better answer, and it is worth being clear about why. A central supply runs at the purity of its most demanding consumer, so your high-volume, low-purity instruments run at that grade too, and pay the air factor for it. A single source is also a single point of failure: if it stops, the whole laboratory stops, not one bench. A buffer vessel covers short interruptions and a reserve cylinder stays part of a sensible plan. And the purity that leaves the generator is not automatically the purity that arrives at the instrument, because pipe routing, low points where condensate can collect and the choice of tubing all have a say.
The version that usually holds up is a split one: analytical instruments on a central, high-purity supply, and the large low-purity consumers on their own, cheaper line. That decision is worth making before the pipework goes in rather than after.
On-site nitrogen compared with cylinders and dewars
Cylinder supply looks cheap because the cost is spread out. Rental runs whether the cylinder is in use or not, delivery is charged per drop, contracts carry price escalation clauses, and full and empty cylinders both need floor space in a building where floor space is expensive. Handling adds to that, and the changeover tends to fall in the middle of a sequence. Liquid nitrogen in dewars covers high peak demand at high purity, but it evaporates whether you use it or not and ties the laboratory to a delivery rhythm it does not control.
On-site generation replaces all of that with an investment and an electricity bill. Compared with liquid-gas supply, a Berg PSA generator typically pays for itself within two to three years.
Standard wear parts
Filters and consumables are off-the-shelf items you can buy on the open market. There is no proprietary parts programme waiting for you after the purchase. It is worth asking every supplier you compare where their filters come from.
Purity to grade 5.0
PSA reaches 99.999 % with residual oxygen from 10 ppm, which is where membrane systems stop well short. That matters as soon as a sensitive detector is on the list.
Room to grow
The NITROBERG® range runs from 1.2 to 1,709.1 Nm³/h of nitrogen, so the same technology covers a single bench, a laboratory floor, and a works laboratory that shares its supply with production.
Direct access to engineering
Sizing questions go to the people who design the machines, not to a call centre. Delivery, commissioning and service come from one source within the BERG Group. Warranty runs three years as standard and up to five years with a service contract.
NITROBERG® sizes for laboratory duty
The figures below cover the part of the range that most laboratory installations fall into. Nitrogen output is shown at grade 5.0 and at 99.9 %, together with the compressed air each size needs at grade 5.0.
| Model | N₂ at 99.999 % | Approx. | N₂ at 99.9 % | Compressed air at 99.999 % |
|---|---|---|---|---|
| NITROBERG® 500 | 1.2 Nm³/h | 20 L/min | 4.1 Nm³/h | 7.7 Nm³/h |
| NITROBERG® 600 | 2.2 Nm³/h | 37 L/min | 7.4 Nm³/h | 13.8 Nm³/h |
| NITROBERG® 700 | 3.4 Nm³/h | 57 L/min | 11.5 Nm³/h | 21.5 Nm³/h |
| NITROBERG® 800 | 4.8 Nm³/h | 80 L/min | 16.4 Nm³/h | 30.7 Nm³/h |
| NITROBERG® 900 | 7.4 Nm³/h | 123 L/min | 25.3 Nm³/h | 47.3 Nm³/h |
| NITROBERG® 1000 | 10.1 Nm³/h | 168 L/min | 34.4 Nm³/h | 64.5 Nm³/h |
The 500 to 900 sizes cover most laboratory installations, including sites feeding several analysers from one source. Above that the range continues into the capacity a laboratory building needs, or a works laboratory that shares a supply with production nitrogen. Applicable NITROBERG® pressure equipment is conformity assessed under PED 2014/68/EU within the certified scope. Engineering and manufacturing are Made in Germany.
For laboratories without a suitable compressed air network, the skid-mounted nitrogen package combines the generator with air generation, treatment, storage and control in one pre-assembled unit, in plug-and-play configurations for NITROBERG® 500 to 900.
FAQ: nitrogen generators for laboratory use
NITROBERG® PSA generators are configured between 97 % and 99.999 %. At 99.999 %, which corresponds to quality grade 5.0, residual oxygen is 10 ppm or lower. That covers carrier gas for GC and GC-MS, collision gas for ICP-MS and inert atmospheres for thermogravimetric analysis. Lower grades are set for applications that do not need the headroom, and they cost noticeably less to run. The purity is a configuration decision made when the system is sized, so it is worth basing it on the instrument specifications you actually have rather than on the highest number available.
Yes, and in laboratories with a growing instrument count it is the normal arrangement. Two things decide whether it works. The purity has to be set by the most demanding instrument on the supply, which means every other instrument runs at that grade and pays the associated compressed air. The capacity has to cover the instruments that genuinely run at the same time, plus headroom for the next analyser. Where a laboratory has both very sensitive detectors and high-volume evaporators, splitting the supply into a high-purity line and a separate lower-purity line is often the more economical answer than putting everything on one grade.
Membrane generators pass compressed air through hollow-fibre membranes and are compact, quick to start and simple to maintain, but the purity they reach in practice tops out around 99.5 %. That covers blowdown evaporation, sample prep, blanketing and a good share of LC-MS duty. PSA uses carbon molecular sieve and reaches 99.999 %, which is what carrier gas for GC and GC-MS, ICP-MS collision gas and TGA atmospheres require. So the real question is not which technology is better, it is whether anything on your bench needs more than 99.5 %. If it does, PSA covers that instrument and the rest of the laboratory with it.
The generator needs compressed air, and the amount depends on the purity you choose. Multiply your nitrogen demand by the air factor from the table above, which runs from 2.3 at 97 % to 6.4 at grade 5.0. If your building already has a compressed air network with enough capacity and suitable air quality, the generator connects to it, and this is often the case where a laboratory sits inside a production site. If not, the skid-mounted package includes air generation and treatment along with the generator.
The nitrogen vessel holds a buffer, which covers short interruptions and gives you time to react. Beyond that, a reserve cylinder remains part of a sensible supply plan, and this is one of the trade-offs to weigh when a laboratory consolidates several instruments onto one source. The reserve strategy is defined together with the system design and the requirements that apply at your site.
No. The wear parts are standard components rather than a proprietary programme, and that keeps the running cost open to competition: you can source filters where you want, compare service offers, and the cost of ownership after the first year is not fixed by one supplier. Over the service life of the machine that usually weighs more than the difference in purchase price. Warranty runs three years as standard and up to five years in combination with a service contract.
Verifying gas quality at the point of use is the operator’s responsibility, and it is worth planning for at the design stage rather than retrofitting it. That means agreeing where the sampling and measuring points sit, what is monitored continuously and what is checked periodically, and how the pipework is routed so that the gas arriving at the instrument still matches the gas leaving the generator. Bring the requirement into the sizing conversation and the measuring points can be designed in from the start.