Questions about Dewar flasks
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A Dewar flask has a double-layer insulation similar to that of a thermos, used to store gases that need to be liquefied at low temperatures. So here comes the question. If this Dewar flask is stored for a long time, even the best insulation will not prevent the temperature inside from rising; the internal pressure will inevitably increase, and this could even lead to an explosion. How is this taken into account?
There is a safety valve that releases pressure automatically, as well as a manual release valve
There is a safety valve that releases pressure automatically, as well as a manual release valve
There is a safety valve that releases pressure automatically, as well as a manual release valve
The safety valve can automatically release the gas phase, and there is also a manual valve that can be opened to release it and relieve pressure.
Taking liquid nitrogen filling as an example, the exhaust valve must be opened during the filling process of liquid nitrogen, which results in the release of a large amount of nitrogen gas. During use, nitrogen vaporization absorbs heat to maintain a low temperature; if it is not used for an extended period of time, the liquid nitrogen warms up and some nitrogen vaporizes, causing the pressure to rise. The system then automatically releases pressure on a regular basis until all the pressure has been released
The Dewar flask contains a liquid that has been liquefied at low temperatures. This liquid vaporizes due to heat conduction, which causes the pressure in the upper gas phase to increase. When this pressure reaches the opening pressure of the safety valve, the valve opens to release pressure; the opening pressure of the safety valve is 1.2 times the nominal operating pressure. Feel free to ask me anything; we are a manufacturing factory.
In fact, Dewar flasks are not designed to be completely airtight; they are equipped with safety valves, and simple plug releases are usually installed at the inlet and outlet for liquid nitrogen.
In fact, Dewar flasks are not designed to be completely airtight; they are equipped with safety valves, and simple plug releases are usually installed at the inlet and outlet for liquid nitrogen.
If it really isn’t to be used for a long time, then it would indeed be a waste.
It has a safety valve; it can generally hold about 10 units, and the pressure will dissipate even if no air is used