The Shanghai HanLeng ultra-low temperature chiller (cryogenic unit) is widely used in high-tech and R&D fields such as aerospace, research institutes, chemical and pharmaceutical industries, new materials, superconductivity, and environmental protection, with temperatures ranging from -100 ℃ to 0 ℃. Create huge economic benefits for users, and win the favor and recommendation of customers with its excellent performance and perfect service. If you need services related to ultra-low temperature cascade refrigeration units (ultra-low temperature chillers), please contact Shanghai HanLeng.
Performance and characteristics of ultra-low temperature chiller unit:
1. All ultra-low temperature chillers are water-cooled. Therefore, there is less loss of cooling capacity, and the unit is prone to oil return (lack of oil or difficulty in oil return can cause compressor connecting rod breakage), and the heat transfer tubes are less likely to freeze and crack.
2. The volume of ultra-low temperature industrial chillers is smaller compared to water-cooled chillers of the same horsepower. The same number of refrigeration units have a larger cooling capacity, and the noise of ultra-low temperature industrial chillers is lower than that of air-cooled chillers during operation.
3. The ultra-low temperature industrial chiller adopts a horizontal condenser and a shell and tube evaporator, and needs to be equipped with a plate heat exchanger for cooling. The unit structure is simple, the heat exchange power output is stable, the effect is stable, and maintenance is convenient.
4. Ultra low temperature industrial chillers are generally screw units. In the refrigeration industry, it is widely believed that large industrial equipment must be cooled to ultra-low temperatures using screw chillers. 1. Ultra low temperature industrial chillers have a relatively large compression ratio requirement compared to compressors, so most cryogenic fields adopt complex cascade compression or two-stage compression systems that are relatively more complex than single compressor systems,
2. The ultra-low temperature chiller operates smoothly, reliably, is not easily damaged, and has low noise. Due to the fact that compressor lubricating oil is supplied by high and low pressure differentials, the built-in oil in the compressor has a high oil separation efficiency. It can also absorb the noise of the unit.
3. The control system of the ultra-low temperature chiller unit adopts a microcomputer LCD touch automatic control system. This system is a localized system, with recommended operation and easy to learn. Accurate control and viewing of the unit's operating status, data query parameter settings, alarm history records, etc. can be quickly achieved by touching the LCD display screen.
4. The ultra-low temperature chiller unit is a finished product, which only needs to be connected to water and electricity on site and filled with sufficient refrigerant when transported to the installation site. After being debugged by the refrigeration engineer, it can be put into operation.
5. The ultra-low temperature chiller unit is equipped with a large volume capacity snow storage tank to ensure sufficient snow, multiple plate heat exchangers to ensure sufficient heat transfer power, and a gas-liquid separator at the end of the refrigeration return liquid to ensure that no liquid enters the compressor and causes the connecting rod to break, avoiding the compressor from being scrapped as a result.

Specific application areas of cryogenic units:
1. Pharmaceutical: synthesis, hydrolysis, esterification, etherification and other processes that require temperature control.
2. Chemical industry: distillation and purification, rubber crushing, low-temperature grinding.
3. Metal processing: low temperature assembly, low temperature sticking.
4. Food: Processing and storage of ultra-low temperature foods such as tuna.
5. Electronics: Environmental testing of components.
6. Aerospace: Heat sink experiment, component environment simulation test.
7. Environmental Protection: Waste gas condensation and recycling, net emissions.
Advantages of ultra-low temperature chiller (cascade chiller) compared to liquid nitrogen:
1. The cost of using liquid nitrogen is 7-10 times that of using ultra-low temperature cascade refrigeration units; The vaporization heat of liquid nitrogen is 5.6KJ/mol=200kJ, the refrigeration power is 1kw. h, and 18KG=22 liters of liquid nitrogen are required.
2. Low temperature refrigeration units can accurately control temperature, while liquid nitrogen temperature control is more difficult;
3. The transportation and storage of liquid nitrogen are very complicated, and once interrupted, production will stop;
4. The use of liquid nitrogen carries certain risks and requires a license for use.
Application of refrigerant:
When ultra-low temperature chillers (cascade chillers) are applied in industries such as pharmaceuticals, chemicals, and aerospace heat sink experiments, a refrigerant circulation system is usually required between the ultra-low temperature freezer (cascade chiller) and the user's load reaction tank. The main reasons are:
1. The load volume of general users is relatively large. If the load requires uniform temperature, it must be filled with refrigerant. However, at room temperature, a large amount of low-temperature refrigerant will turn into gas, and the volume and pressure of the gas will be huge, which the equipment itself will not be able to meet;
2. The load on the user's site is far away from the refrigeration room, and the load area is usually a clean, explosion-proof, and quiet area. The refrigerant circulation system can separate the cryogenic unit and the load area, making the entire system safer and more reliable;
3. Usually, the cooling capacity is achieved by cooling the materials inside the load through the heat exchange coils. Once the heat exchange coils leak, it may contaminate the materials. The refrigerant system usually uses substances that are in contact with the material solvent, so even if there is a leak, the possibility of contamination can be completely avoided;
4. Refrigerant is also a carrier for storing cold energy, which can be adjusted by refrigerant when the load changes significantly. This is beneficial for temperature control and energy conservation. Generally speaking, the greater the load fluctuation, the more refrigerant is required.
5. The heat exchange efficiency is higher than that of liquid nitrogen. Liquid nitrogen uses latent heat of evaporation to release cooling energy. After absorbing heat, liquid nitrogen becomes gaseous, and a mixture of vapor and liquid phases occurs inside the coil, resulting in significant gas resistance and a sharp decrease in flow rate. This prevents liquid nitrogen from fully contacting the tube wall, greatly reducing heat transfer efficiency.
Refrigerants generally use glacier refrigerants (freezing point -118 ℃), dichloromethane (boiling point 40 ℃, freezing point -95 ℃), alcohol (boiling point 78 ℃, freezing point -114 ℃), dichlorofluoroethane (boiling point 32 ℃, freezing point -103 ℃), trifluorodichloroethane (boiling point 28.7 ℃, freezing point -107 ℃), difluorochloroethane (boiling point -10 ℃, freezing point -131 ℃), which are non-toxic, non flammable, environmentally friendly, and inexpensive. The circulation of refrigerant adopts a magnetic circulation pump to reduce pollution and the impact of low temperature on bearing sealing.

Performance characteristics of ultra-low temperature chiller unit:
1. Temperature adjustment range: -60 ℃ or -100 ℃ to+100 ℃, with a temperature control accuracy of ± 1 ℃.
2. Refrigeration: Adopting cascade refrigeration, cooling capacity: 1 to 1000KW available for selection.
3. Control system: programmable PLC with touch screen
4. There are RS485 and R232 interfaces that can communicate with computers to receive computer settings, control, and transmit measured temperatures to the computer.
5. Imported heat transfer fluid can be selected
6. The transmission pump adopts a magnetic pump, which has no leakage, no pollution, and high head
7. The storage tank and pipeline are sealed and pressurized to prevent refrigerant evaporation, condensation, and freezing, and there is a liquid level indicator
8. Small load heating can be achieved by using the hot gas bypass of the compressor to heat the load
9. Multiple alarm protections: water interruption, high water temperature, circulation pump failure, compressor overheating, high pressure, overcurrent, phase loss, phase continuity, etc
10. Cooling method: Air cooling or water cooling can be selected, and the air-cooled condenser can be placed outdoors
Due to the wide range of industries and applications in which ultra-low temperature chillers are used, it is not possible to fix the model, and most of them need to be customized according to the actual situation of the user. We may ask the following questions:
1. What temperature is required? What is the required volume?
2. What materials are being processed? What is the weight? What are its specific heat capacity, vaporization heat, and solidification heat?
3. How long does it take to cool down or heat up? Each production cycle?
4. Other heat losses: reaction heat, stirring heat, circulation pump, pipeline, storage tank;

Based on the answer to the question, both parties will discuss an optimized solution.
The main components of the Shanghai HanLeng ultra-low temperature chiller unit (cascade refrigeration unit) are all made of world-renowned brands, such as compressors mainly using Copeland, Bitzer, Danfoss, Alfa Laval, Siemens, Schneider, etc. Large systems use screw compressors and are equipped with economizers to improve system efficiency. The small system adopts a semi closed piston compressor. The evaporator of the cryogenic unit adopts a stainless steel plate heat exchanger, which provides a large and efficient heat transfer area for the deep cooling ultra-low temperature freezer (cascade refrigeration unit) in a compact space.