Why does the LPG tank valve freeze?

by daniel
(canada)

My barbecue hose (the part that fits into the tank) frosts up the metal valve part. Why does the LPG tank valve freeze?

Answer:-

I'm not a professional scientist but I do remember a few things about the laws of energy and thermo dynamics.

Consider water; in order for it to vaporise (ie. boil) it needs energy. The energy you provide is in the form of heat in the kettle or on your stove top.

The same thing applies to LPG, when it's in the tank it's a liquid and when released from the tank it's a gas. The process of transition from liquid to gas takes energy just like water but in this case the energy requirement is satisfied in the form of heat from the atmosphere.

The transition from liquid to gas takes place in the valve and any heat energy available is absorbed at this point therefore causing your tank valve to cool and if atmospheric temperature is sufficiently low (as in your case) it will freeze.

Once you've stopped using the gas your valve will gradually come back up to ambient temperature so that you can shut it off but how long this will take is dependent on the ambient temperature itself.

See Also:-

Barbecue Tips
Barbecue Grill Comparisons
Outdoor Kitchen Barbecue Islands
Tabletop Gas Grill

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