Low temperature/ultra-low temperature cascade refrigeration unit is a new generation of low temperature/ultra-low temperature refrigeration unit designed and developed by the main technical staff of our company, which is based on decades of experience in designing low and medium temperature chiller units, and the advanced technology of the similar products at home and abroad, which is characterized by high efficiency, energy-saving, environmental protection, high reliability, etc. The application of a number of advanced technologies has made the comprehensive technical level of this product reach the leading level in the world, and it has applied for a national patent. The product has applied for national patent. This series of equipment adopts two different temperature zones of refrigerant two-stage mating operation, overcoming the single-stage compression refrigeration cycle pressure ratio is too large, as well as a single refrigerant two-stage compression of low temperature compressor suction temperature is low, low transmission coefficient and other shortcomings. It can provide low-temperature cold source from -30℃ to -145℃, and the maximum refrigeration capacity of a single unit can reach 910kW under the condition of evaporating temperature of -45℃, with a wide range of temperature and cold capacity, which is widely used in the fields of pharmacy process of pharmaceutical industry, low-temperature laboratory of automobile, electronics, aerospace industry, low-temperature recovery of oil and gas of petroleum and chemical industry as well as ultra-low-temperature processing and quick-freezing and refrigeration of food industry. Among them, CWL series of refrigerant-carrying units can provide low-temperature refrigerant from -30℃ to -140℃; CUL series of compression condensing units can provide low-temperature refrigerant from -35℃ to -145℃.