⑩ 液位计 ：比较直观地指示容器内液面的高低，安装位置应便于操作人员观察和检修 。
The main structure and functions of dewars are as follows:
① Outer cylinder: in addition to protecting the inner barrel, it also forms a vacuum interlayer with the inner barrel to prevent the invasion of heat outside the bottle and reduce the natural vaporization of cryogenic liquid in the bottle;
② Inner cylinder: Reserve low temperature liquid;
③ Vaporizer: through the heat exchange with the inner wall of the outer barrel, the liquid gas in the bottle can be transformed into the gaseous state;
④ Liquid valve: control Dewar bottle to fill or discharge liquid from the bottle;
⑤ Safety valve: when the pressure of the vessel is greater than the larger working pressure, the pressure will be released automatically, and the take-off pressure will be slightly greater than the larger working pressure;
⑥ Discharge valve: when the Dewar bottle is filled with liquid, this valve is used to discharge the gas in the gas phase space in the bottle, so as to reduce the pressure in the bottle, so as to fill the liquid quickly and smoothly. The other function is that when the pressure in the Dewar bottle exceeds the higher working pressure during storage or other conditions, the valve can be used to manually discharge the gas in the bottle to reduce the pressure in the bottle;
⑦ Pressure gauge: indicating the pressure of the inner cylinder of the bottle;
⑧ Booster valve: after the valve is opened, the liquid in the bottle will exchange heat with the outer cylinder wall through the supercharging coil, vaporize into gas, and enter the gas phase space on the upper part of the inner cylinder wall, so as to establish a certain driving pressure (internal pressure) of the cylinder, so as to drive the low-temperature liquid in the bottle to flow;
⑨ Use valve: it is used to open the pipeline channel between Dewar liquid vaporization circuit and user gas inlet end, and it can also be used to control gas flow rate;
⑩ Liquid level gauge: it can directly indicate the liquid level in the container, and the installation position should be convenient for the operator to observe and repair.
