Ultra-low temperature refers to the temperature range of -40℃ to -80℃ adopted in food processing and industrial production. This temperature range is widely applied in household, commercial and medical scenarios, as illustrated below: ● Quick-freezing and storage of high-grade aquatic products (e.g. tuna); ● Storage and production of pharmaceuticals; ● Processing of special foods (e.g. ice cream); ● Preservation of cryogenic biological samples (e.g. seeds of rare species); ● Low-temperature performance testing of electronic components; In addition, it can provide a low-temperature cold environment required for material performance tests at subzero temperatures. For instance, it supports low-temperature impact tests ranging from -46℃ to -58℃ on welds of cryogenic pipelines in ethylene liquefaction units.