LPG

Pressure is reduced, liquid phase changes to gas absorbing heat from environment.

now research phase change.

Brad

Depending upon the speed of gas usage, ice may form on the outside of the cylinder.

This effect is used by some temperature sensitive films, they stuck on the outside of the cylinder, to show the level of the liquid gas inside as generally, the "gas" area part will be a degree or so colder than where the liquid still is, but only when gas is being drawn off and a short time later!!

It is liquid only because it's confined in cylinder. Necessary space above the liquid in the tank provides head pressure--also keeps LPG in liquid space from boiling away. Open valve on tank and gaseous PG escapes under head pressure; liquid boils and vapor takes place of "escaped" gas. Close valve, again confine fuel inside tank. Head build again to point of stopping boiling of liquid. Steady state restored. By confinement, temperature of liquid and gas under pressure is kept below boiling point of the liquid.

Post #1 basically told everything, I added a point in #2 and you come along and tell it all again slightly different in post #3..... in spite of the fact that nobody requested more detail of what had been written. What are you? a Robot teacher in real life?

Waste of brain energy here....

Also, to get any sort of respect on CR4, you need to have a name and be logged on under that name.......and try not to repeat what went on before....unless a request exists...

You know the saying "look before you leap"?, well here is a new one "read fully and understand before posting"...

Redundancy is the key to understanding, don't you see. Also not mentioned was the exothermic nature of the state change from liquified to gaseous.... by which a vessel-full of liquified gas can, to a degree, self-regulate its temperature--thus remaining in liquified form. But thanks for letting me know that it's not just you who disrespects me for attempting--apparently in vain--to add just a little bit to the discussion. I'll consider this....whether I should really sign on as you suggest.

If you want to become a respected member, try to read fully what has already been said fully and not repeat it UNLESS you are specifically asked to elaborate on a particular item. Just assume that if there are no further questions, everyone understood enough!

If you posted at almost the same time, your entry is now doubled, it is not so easy, but you can edit your own entry for a further 15 minutes as a proper name, not as a guest...I have even scrubbed the contents and just said, "So and so has just published what I wanted to. Erased."

Having a proper name means that you are identified and identifiable. Comments from a guest (any guest) are just lumped together and often ignored, because if you are not keen to be identified, then your data is also possibly questionable.....

We get guests who from time to time just make trouble and ruin a blog as most people then just leave it as they cannot be bothered to argue with a bad ghost!! Some people get their kicks this way. To my mind it shows some serious personality traits.....So if you do not want to be possible (miss)identified in this manner, you need a name.

If you don't put a location with your name, do not take offense (as some do!) if you get information that is not applicable to your location......give at least the country and if in the USA, the state please.....no need to give your home town, but you can if you wish.....

Use the spelling checker ALWAYS, it is USA spelling, not UK, but a lot of non English speaking people (as a first language) might have trouble with bad spelling. Sadly there seems to be no grammar corrector as far as I can tell.....I could use it often!!!

Lastly, if you screw up, then own up and do not try and bluster out of it. It can happen to anyone, especially if a poster is not very clear in what he writes and you misunderstand it. Nobody here will hold honesty against you......

Thank you.

Fair comment Andy, and you were kind enough not to correct errors in guests posts.

Consider a perfectly-lagged theoretical steam boiler. Liquid (water) is in contact with vapour (steam) at equilibrium. Upon opening a valve to use the steam, vapour leaves the vessel causing a slight reduction in pressure. This is sufficient to cause more liquid to boil to fill the space left by the vapour that has left. Of course, in the case of this boiler, the pressure is maintained by adding heat to the value of the heat that has left in the vapour upon departure. If heat cannot be added, the temperature and pressure will fall. → Steam tables.

The volume occupied by any liquid is its mass divided by its density at a given temperature. In the case of water, its density varies slightly with temperature from a maximum at about 4degC of 1000kg/m3 to 958kg/m3 at 100deg C, for example (with further reductions as pressure is applied above this temperature). So hot water is more buoyant than cold water, a feature used to advantage in the design of hot water cylinders for domestic service: the hot water stratifies at the top of the vessel, which is where the outlet connection is made.

It doesn't matter if the actual fluid is water or LPG (though the thermodynamic and transport properties are rather different); it's the principles that are important and perhaps water and steam are easier to visualise.