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Thermal contraction / vacuum rating

Thermal contraction / vacuum rating

Thermal contraction / vacuum rating

(OP)
I have a section of small diameter (3/8") tubing that will be isolated between two closed valves, capturing hot water between the valves.  When the water drops to ambient temperature, density changes will create a vacuum of an estimated 1 to 1.5 psia between the valves (Reverse of thermal expansion problem).  

Any guidance on determining the wall thickness required for obtaining a given vacuum rating would be appreciated.

RE: Thermal contraction / vacuum rating

ewcrabtree-

Internal pressure will govern your design. A quick check of a Section VIII-1 design approach with carbon steel indicates a required thickness of 0.004" for full vacuum - 10 times your requirement. I'll just bet that your tube is thicker than 0.004".

jt

RE: Thermal contraction / vacuum rating

ewcrabtree,
           jte's got the answer. With such a small diameter it will be able to "eat" full vacuum.

RE: Thermal contraction / vacuum rating

(OP)
Thanks y'all.  I appreciate the help!

The wall thickness is, indeed, greateer than 0.004" -- 0.065" for 16 BWG SS tubing.

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