Negative Pressure Piping

[cantiqa78]

Hi Everyone,

I want to ask an explanation about what is the term Negative Pressure Piping usually refer too? Could any of respected member forum here give me an enlightment please.....
Thank you

 

[JLSeagull]

Vacuum is negatave pressure as compared to the atmosphere. I don't use the term "negative pressure piping" but have worked with vacuum applications.

 

[rcooper]

I'd use Sub-atmospheric

 

[BigInch]

I use absolute.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain

 

[JohnBreen]

cantiqa78

Generally, negative pressure piping is piping with an operating internal pressure that is less than atmospheric pressure.

In some (few) applications, where jacketed piping is used (cryogenic applications come to mind) the pressure in the annular space between the outer pipe and the inner pipe is higher than the internal pressure of the inner pipe. In these cases the inner pipe is designed as though it were a "negative (internal) pressure system".

John

 

[BigInch]

Yes exactly!
.. and for offshore pipelines, aircraft, space vehicles too.

Back to Earth, absolute references can also be helpful when you're pipeline starts at sea level and runs to a terminal at 2800 meters.

An atmospheric reference in those situations is useless.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain