TEMPERATURE FOR FULL VACUUM DESIGN

[roker]

Hello all and happy new year,

In designing shell and tube heat exchangers (which are considered pressure vessels, so the question refers also to pressure vessels): what are the criterias or guidelines or rules for specifying the temperature at which full vacuum design mechanical calculation will be performed?

regards,
roker

 

[nickelkid]

What temperatures are you operating at? What materials are you using?

 

[djack77494]

You should set the vacuum design temperature in the same manner as you set the pressure design temperature. Generally, you determine the maximum likely operating and upset temperature that will occur at the maximum positive and negative pressures and apply an appropriate (and hopefully predetermined) margin. It's actually a bit more complicated than this; if there are combinations of temperature and pressure/vacuum that contend for the most servere, then you must determine which generates the worst stress situation.

 

[CJKruger]

Roker, I use the following phylosphy:

Specify full vacuum if:
1) Equipment is steamed out (only some companies).
2) Equipment may be subject to vacuum conditions during an operating cycle:
-- If evacuated during startup.
-- If vacuum can develop as a result of heat loss.
3) The corresponding temperature at full vacuum is a standard value (company specs) or the normal operating temperature.

 

[Shmulik]

thread794-196374