1. Measurement method, take a wooden stick 80cm long, peel it and apply black, then set a scale every 5cm from the end. When measuring, put the zero scale down, insert the liquid nitrogen tank into the bottom of the tank. After 5~10s, the length of the frost is the liquid nitrogen level in the tank. This method is neither safe nor the reading error is large;
2.For the weight measurement method, first weigh the weight of the empty tank, then weigh the weight when filling the liquid nitrogen, and then subtract the weight of the empty tank, that is, the total weight of the liquid nitrogen in the tank, and then every 3~5d The weight of a liquid nitrogen tank, this method has the drawbacks of time-consuming and laborious.