On July 7, 2020, the project of 'the high and low temperature simulation test device for a certain type of nozzle oil source pump' designed and manufactured by our company for a certain department of China Aviation Development Co., Ltd. passed the final acceptance at the customer's site. The project innovatively adopts liquid nitrogen cooling and heat exchange technology to realize high-precision low-temperature fuel temperature control, and the temperature control accuracy can reach ± 1℃。 Compared with the conventional way of compressor refrigeration, the liquid nitrogen refrigeration mode has the advantages of low construction cost and strong refrigeration capacity. Our company has obtained the utility model patent certificate of this technology.