Common method of liquid nitrogen capacity inspection:
1. Measuring method, taking a long 80cm stick, peeled and coated with black, then starting at one end of every 5cm to set the moment, measurement, the 0-scale downward, from the liquid nitrogen cans inserted into the bottom of the pot, after 5~10s out, the length of frost can be liquid nitrogen level, this method is not safe, reading error is large;
2. Weighing method, first call the weight of the empty cans, and then weigh the weight of liquid nitrogen, then minus the weight of empty cans, that is, the total weight of liquid nitrogen, after every 3~5d is called a liquid nitrogen tank weight, this method has a time-consuming and laborious disadvantage.
3. Use liquid level alarm
Liquid nitrogen can be injected into the tank, as soon as the lid plug, after each 3~5d the liquid nitrogen tank ultrasonic liquid level measurement display device plug in the liquid nitrogen tank mouth. Starting the liquid level alarm device, ultrasonic transmitter transmits ultrasonic beams to liquid nitrogen surface in liquid nitrogen tank. Acoustic waves are reflected by the liquid nitrogen surface, partially reflected echo received by ultrasonic receiver, through synchronous receiving circuit in real-time and synchronous sending ultrasonic echo signal, SCM to ultrasonic wave propagation speed and time in the air can be measured in the high level, and real-time display of liquid crystal display.