Grades for NGP and NGP+ duty
Four SorbiTech grades cover the purity span these generators are configured across, from blanketing duty at 95 percent through to the high purity end. Selection follows the outlet specification the unit has to hold and the pressure it runs at, rather than the frame size or the model reference.
| Atlas Copco range | Technology | Published purity | Replacement media |
|---|---|---|---|
| NGP (NGP 10 to 115) | Pressure swing adsorption | 95 to 99 percent | Carbon molecular sieve |
| NGP+ (NGP8+ to NGP200+) | Pressure swing adsorption, adaptive cycle | 95 to 99.9995 percent | Carbon molecular sieve |
| NGM | Hollow fibre membrane | Varies with configuration | None. A membrane unit holds no adsorbent |
Range and purity data as published by Atlas Copco. Achieved purity depends on the configuration and on the air supply.
How SorbiTech CMS works in an Atlas Copco PSA system
Compressed air enters one of two adsorber vessels under pressure. Oxygen moves into the pore structure of the sieve far faster than nitrogen does, so nitrogen passes through and leaves as product while oxygen stays on the bed. Releasing the pressure lets that oxygen go, and the two vessels alternate so supply is continuous. The mechanism is covered in how on site nitrogen is made, and the duty under PSA nitrogen generation.
On the NGP+ the controller varies the cycle with demand and temperature. As a charge ages it shortens the adsorption step to hold purity, so the first sign of an ageing bed is usually rising compressed air consumption rather than a fall in purity.
Achievable nitrogen purities
The same equipment is configured for very different outlet specifications, and the grade of sieve follows that target.
| Purity | Typical duty | SorbiTech grade |
|---|---|---|
| 95 to 98 percent | Tank blanketing, general purging, fire prevention | CMS 260L |
| 99 to 99.9 percent | Packaging and general process supply | CMS 260L or CMS 350KT |
| Up to 99.99 percent | Laser cutting assist gas, heat treatment | CMS 350KT or CMS 420KT |
| 99.999 percent and above | Analytical, electronic and pharmaceutical duties | CMS 450HP |
Indicative mapping, confirmed against the duty before supply. Specifications sit on the adsorbent product pages.
Compressed air consumption rises steeply as the purity target tightens, so a generator asked to hold more purity than the process needs will consume more air for the whole of its life.
Applications of CMS in Atlas Copco PSA nitrogen generators
- Food and beverage. Modified atmosphere packaging, tank blanketing, line purging.
- Pharmaceutical and life sciences. Vessel inerting and protection of oxygen sensitive product.
- Petrochemicals and refining. Purging, blanketing and maintenance inerting.
- Oil and gas. Pressure testing, pipeline purging, safety inerting.
- Metal fabrication. Laser cutting assist gas and controlled atmosphere heat treatment.
The wider field is covered under industrial gas and air separation.
Why choose SorbiTech CMS for an Atlas Copco system
- Grades across the full purity span. Four grades covering 95 percent blanketing duty through to high purity service, so the charge is matched to the generator rather than to a single stock item.
- Consistent pellet form and size. Cylindrical pellets to a controlled size distribution, which is what lets a bed pack evenly and hold its pressure drop.
- Documented on despatch. Released with a certificate of analysis covering the properties that govern performance in a pressure swing cycle, under an ISO 9001:2015 quality system.
- Sizing and loading guidance. Quantity is calculated from the adsorber volume and the bulk density of the grade, and loading guidance accompanies the supply so the bed is filled densely rather than poured.
- Support on selection. Technical support on grade selection, quantity and operating guidance. Where a spent sample can be provided it helps show whether a decline came from ageing or from contamination upstream.
Where a generator has reached the end of its economic life rather than its charge, a replacement package is covered under PSA nitrogen generation packages. Media for other classes of installed equipment is listed under compatible media.
Compatibility and supply
SorbiTech carbon molecular sieve is manufactured to SorbiTech's own specification and supplied as a compatible charge for pressure swing nitrogen generators built by other manufacturers, including NGP and NGP+ units from Atlas Copco. Grades are selected against the duty of the individual unit and released with a certificate of analysis.
Engineering design, technical support and performance guarantees are available, and are set against the specific unit and duty following technical review.
Where a unit remains under an original manufacturer warranty or service agreement, the terms of that agreement apply.
Frequently asked questions
Does an NGM unit need carbon molecular sieve?
No. The NGM range separates nitrogen through hollow fibre membranes and holds no adsorbent, so there is nothing to recharge. Only the PSA ranges, NGP and NGP+, take a carbon molecular sieve.
How much carbon molecular sieve does a generator take?
The quantity follows from the internal volume of the adsorber vessels and the bulk density of the grade supplied, so it is calculated rather than read from a parts list. Where the vessel dimensions are available the charge is worked out in advance, and where they are not, the volume can be established when the adsorber is opened.
Why did purity look stable and then fall away quickly?
On the NGP+ the controller varies the cycle with demand and temperature, and it shortens the adsorption step as bed capacity declines in order to hold the purity setpoint. The loss shows up as higher compressed air consumption rather than on the analyser, until there is no adjustment left. Air consumed per unit of nitrogen is the earlier indicator.
Specify a replacement charge for your generator
Tell us the model designation and the purity the generator has to hold, and we will advise on grade and quantity.