Cryogenic dewar tank
Dewars have the following structure and functions.
① Outer barrel: In addition to protecting the inner barrel, it also forms a vacuum sandwich with the inner barrel to prevent the intrusion of heat from outside the bottle and reduce the amount of natural vaporisation of the liquid inside the bottle.
②Inner barrel body :reserve low temperature liquid .
③ Vaporiser :converts the liquid gas inside the bottle into a gaseous state through heat exchange with the inner wall of the outer barrel.
④ Liquid valve :controls the Dewar bottle for liquid filling or discharging liquid from the bottle.
⑤ Safety valve: when the pressure of the container is greater than the maximum working pressure, the automatic pressure relief, its starting pressure is slightly greater than the maximum working pressure .
⑥Discharge valve: When filling the Dewar bottle with liquid, use this valve to discharge the gas in the gas phase of the bottle to reduce the pressure inside the bottle so that the liquid can be filled quickly and smoothly. Another function of the valve is to discharge the gas from the bottle when the pressure inside the bottle exceeds the maximum working pressure in storage or under other circumstances, in order to reduce the pressure inside the bottle.
(vii) Pressure gauge: to indicate the pressure of the cylinder inside the bottle.
8) Booster valve: When this valve is opened, the liquid inside the bottle will exchange heat with the outer cylinder wall through the booster coil and vaporise into gas, which will enter the gas phase space on the upper part of the inner cylinder wall, so that a certain driving pressure (internal pressure) can be established in the cylinder to drive the cryogenic liquid inside the bottle and make it flow.
The valve is used to open the piping between the liquid vapourisation circuit of the Dewar cylinder and the inlet end of the customer’s gas, and also to control the flow rate of the gas.
⑩ Liquid level gauge: a relatively intuitive indication of the liquid level in the container, the installation location should be easy for the operator to observe and maintenance.
