Laboratory high-purity liquid nitrogen machine

The working principle of the laboratory high-purity liquid nitrogen machine is based on air separation technology, but it has been precisely optimized for scientific research needs. The core focuses on two major goals: efficient nitrogen production and ultra-high purity. The entire process can be divided into three key stages: air pretreatment, low-temperature distillation, and liquid nitrogen storage.

The core principle of laboratory adaptation: a balance between efficiency and purity

　　Laboratory high-purity liquid nitrogen machineThe working principle of the system is based on air separation technology, but it has been precisely optimized for scientific research needs. The core focuses on two major goals: efficient nitrogen production and ultra-high purity. The entire process can be divided into three key stages: air pretreatment, low-temperature distillation, and liquid nitrogen storage. In the air pretreatment stage, the equipment first intercepts dust particles in the air through a primary filter, and then enters an oil-free air compressor for pressurization - oil-free design is one of the core requirements of laboratory models, which can avoid oil mist pollution and prevent cross contamination of subsequent experimental samples. The pressurized air will pass through a freeze dryer and a double tower molecular sieve adsorption system in sequence. The former lowers the dew point of the air to below -40 ℃ and removes most of the moisture; The latter precisely adsorbs trace impurities such as carbon dioxide and methane, ensuring that the purity of the air entering the distillation system reaches 99.99% or higher.

　　Laboratory high-purity liquid nitrogen machineThe deeply purified air will enter the vacuum insulated cold box. Inside the cold box, air and low-temperature nitrogen reflux undergo heat exchange through a plate fin heat exchanger, gradually reducing the temperature to around -170 ℃, approaching the critical point of nitrogen liquefaction. Subsequently, the pre cooled air enters the micro distillation tower and utilizes the boiling point difference between nitrogen (boiling point -195.8 ℃) and oxygen (boiling point -183 ℃) to achieve component separation. In the distillation tower, the rising gas phase is in full contact with the falling liquid phase, and oxygen is more easily condensed into the liquid phase due to its higher boiling point, while nitrogen is enriched at the top of the tower to form a high-purity gas phase. These high-purity nitrogen gases are then depressurized and cooled through a throttling expansion valve to reach liquefaction conditions, forming liquid nitrogen with a purity of ≥ 99.995%, which is directly stored in the small Dewar tank that comes with the equipment. Unliquefied nitrogen gas is used as reflux gas to participate in heat exchange and achieve energy recovery. The entire cycle is based on an improved Linde cycle, which reduces energy consumption by more than 30% compared to traditional models and is more in line with laboratory energy-saving needs.

Exclusive Laboratory Design: Large Functions in Small Spaces

The structural design fully considers the particularity of scientific research scenarios, with compactness, intelligence, and safety as the core principles. Complex systems are integrated into a space of about 1 square meter, suitable for limited spaces such as laboratory workbenches and fume hoods. Its core components include five modules, which work together to meet the diverse needs of scientific research experiments. Air compression modules often use silent screw air compressors, with operating noise controlled below 55dB (A) to avoid interference with laboratory environments; In addition to conventional components, some models also add a sterilization filter to the purification module, which can filter bacteria, viruses, and other microorganisms in the air. It is particularly suitable for scenarios with high sterile requirements such as biosafety laboratories and cell culture laboratories.

The design of the cold box and storage module also meets the needs of the laboratory. The cold box adopts a double-layer vacuum insulation structure, wrapped with high-performance insulation material on the outer layer, and the cold loss rate is controlled below 0.5%/day, effectively reducing the volatilization of liquid nitrogen; The built-in Duwa tank typically has a capacity of 50-200 liters and can meet the laboratory's continuous use needs for 1-7 days. The tank is equipped with high-precision liquid level sensors to monitor liquid nitrogen storage in real-time. The control system is the "brain" of the laboratory liquid nitrogen machine, using a PLC intelligent control system, equipped with a 7-inch touch screen, supporting convenient operations such as "one click start" and "timed start stop". Ordinary laboratory personnel can master it proficiently after 10 minutes of training. At the same time, the system can automatically record parameters such as nitrogen production, purity, and operating time. Some models support integration with laboratory LIMS systems to achieve full traceability of experimental data and meet scientific research data management standards.