Dewar flasks, also known as cryogenic flasks, are used to store and supply liquid products (such as liquid nitrogen, liquid oxygen, liquid argon, etc.). Generally speaking, the air volume of a 180MPa Dewar barrel is equivalent to that of a 1800-2400psi steel cylinder. Since the Dewar barrel must realize the functions of fluid supply, air supply and pressure control, its valves and valve parts are numerous
Dewar top structure
The Dewar contains four on-off valves, one for each gas connection, liquid connection, exhaust connection, and pressure circuit. Most dewar manufacturers classify these four valves by color: green for gas phase and booster valves, blue for liquid phase valves, and gray for exhaust valves. In addition, there are pressurization circuits, liquid level gauges, pressure gauges, safety valves and rupture discs.
Gas phase valve/liquid phase valve: used for gas/liquid outlet.
Booster valve: It plays the role of adjusting the pressure of the booster circuit. The pressure regulated on the booster valve can be read on a scale (customers are not advised to adjust the pressure on the booster valve). After the boost valve in the booster circuit is open normally, there is frost on the booster circuit (if there is no frost, it means the cylinder is empty or the booster circuit is blocked).
Safety valve: In a general concept, a safety valve is a safety device that protects under special circumstances. However, the safety valve on the Dewar bucket works and jumps almost every day, which will affect the spring of the safety valve, resulting in a relatively high failure rate of the safety valve.
Liquid Level Indicator: Displays empty, half and full drums. However, the liquid level gauge cannot be used for accurate measurement, it can only be used as an indication reference.
Dewar barrel internal structure
A Dewar is actually a storage tank. Its interior is composed of an inner cylinder, an insulating layer, a vacuum layer, and an outer cylinder. , with gasification coil and pressure coil in the middle.