"vapor freeze" Ow, my head.

I was discussing leaving the suction side of a flooded processing system open at all times to insure no liquid was trapped in it during cleanup. A person in authority, but not an engineer by any means, asked if I was worried about "vapor freeze". I have been around industrial refrigeration now for 30+ years but have never heard that term or experienced anything that it would describe. Is there such a thing? and how would it effect a 3 inch suction line running +5psig house pressure. The liquid feed to this piece of eauipment is closed prior to clean up.

Well, that is something I have not heard before. Never. Did he even describe what a vapor freeze might be?

One thing I have heard of before, is people making up terms to describe something they don't understand though.:D

Hi JH Taylor/ US Iceman,
I have not heard of it this side of the pond, But if you find out what it might be please let me know.
thanks
Arthur

The only thing that I can find about vapor freezing via our friend Google is about freezing or defrosting sperm.

So perhaps he was testing you to see how strong yours are ;)

Quote:

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Originally Posted by JHTaylor

I was discussing leaving the suction side of a flooded processing system open at all times to insure no liquid was trapped in it during cleanup. A person in authority, but not an engineer by any means, asked if I was worried about "vapor freeze". I have been around industrial refrigeration now for 30+ years but have never heard that term or experienced anything that it would describe. Is there such a thing? and how would it effect a 3 inch suction line running +5psig house pressure. The liquid feed to this piece of eauipment is closed prior to clean up.

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Maybe he was refering to the cold spot produced when liquid refrigerant vapourises.
(Try licking the back of your hand and blowing across it )
Maybe he was trying to be clever and refering to possible thermal shock from the resultant evaporative action etc. etc.
Or maybe he was just someone trying as you say to be clever.
Who knows?
Grizzly

Welcome to the Forum JH!
Tried to send you a PM, but could not
As it turns out I live just down the road from one of your plants
Again welcome to the Forum.
And I have never heard of Vapor Freeze either!

maybe he had his words wrong and meant more "freezing the suction line" ??

Ice

The only thing I can think of is this; when you pump down a coil some liquid may remain. It can still be liquid at the lower pressure (even after a pump down). This remaining cold liquid can flash off if disturbed by hitting the pipe or by warming up slightly.

And, where this liquid forms a puddle you would see frost even while the remaining pipe, etc. could be warm.