Avoid These 8 Liquid Nitrogen Generator Pitfalls: Advice from Professional Manufacturers

Small scale liquid nitrogen generators primarily rely on two types of cryocooler technologies to achieve the necessary ultra-low liquefaction temperature: the hybrid Pulse Tube cryocooler and the Gifford-McMahon (GM) cold head. These are cryocoolers that have been put into batches commercial production and internationally certified such as CE and UL. Immature or newly developed production technologies often lack a verified history of long-term, reliable operation. This makes it exceptionally difficult for non-professional users to accurately assess their quality and durability.

To cut costs, some manufacturers replace proper water chillers with air-cooled condensers that has no refrigeration capacity and label the operating temperature at a restrictive "0-25°C". Since most conventional laboratories consistently operate above 25°C, this design is fundamentally unacceptable. The critical pitfall is that the unit will automatically shut down when the ambient temperature exceeds its narrow range, leading to failed experiments and significant operational downtime.

Some manufacturers advertise a generous output like 10L/day to justify a low price competition. However, independent verification often reveals actual production is significantly lower (e.g., only 6L/day), rendering the equipment inadequate for its intended use.

A small-scale generator needs to operate for 2-3 days to store enough liquid nitrogen. To compromise for an impractically small size, some manufacturers squeeze 20 liters volume or even smaller in-build dewar into the cabinet. This creates a critical limitation: when liquefaction stops, the liquid level immediately begins to drop due to evaporation. Factoring in the necessary headspace (10-20% nominal capacity) and continuous evaporation, the actual usable liquid nitrogen volume is about 10 liters, making the system inefficient for sustained use.

Some generators are not designed to be maintenance-friendly and rely on on-site services from the manufacturer/distributor, resulting in high subsequent maintenance costs.

Low-priced air compressors typically offer significantly short service life and require part replacements every 4,000 hours, leading to higher long-term consumable costs and bad user experience.

Prioritize pressure swing adsorption (PSA) technology nitrogen generators, which will produce 99.5% and higher purity nitrogen gas while membrane nitrogen generation technology can achieve upmost 98% purity, so you need to carefully evaluate which type meets your needs. Some manufacturers claim over 99.9% nitrogen purity, but actual purity may only be 98%. It is recommended to ask the manufacturer to provide a purity commitment document.

A reasonable operating noise level for laboratory equipment is typically below 63 decibels (dB), with conventional nitrogen generators operating at approximately 60 dB. Therefore, a manufacturer's claim within the range of 60-63 dB is credible, while claims significantly lower than this should be scrutinized.