In the temperature of the forward air into the cooler (hot end temperature, related to the cooling effect of the last cooler of the air compressor or nitrogen water precooler) and the temperature of the return air into the cooler (cold end temperature, under the condition that the temperature of the heat exchanger such as the outlet supercooler and the liquid purifier is not changed, the temperature difference between the thermal end and the temperature difference between the cold end of the refrigerator (both refers to the difference between the temperature of the forward air and the reflow gas participating in the switching) is interdependent. If the hot end temperature difference, cold end temperature difference will is too small; the hot end temperature difference is too small, cold end temperature difference will is too large. This is decided by the cooling balance of the positive and return gas of the cooler. When the ratio of return flow to positive flow volume is larger than...