Steam valves 1

[cooper24]

Can anyone see an advantage / disadvantage to putting a bypass valve/pipework around a parellel slide valve on a HP steam system 110 bar and IP steam system 30 bar

 

[ccfowler]

cooper24,

Can you describe your system in more detail? With more information, perhaps some useful advice could be provided.

 

[jherbert]

The arrangement described is typical; used to
slowly introduce steam and heat up pipework
after maintenance. Much much safer than trying
to crack open a full bore 110 Bar valve. Is that
the question?

 

[poetix99]

Yes, as "jherbert" has said, bypass of a main, HP or IP valve for warm-up is common.

You should take precautions that if the piping in question is for supply to a steam turbine (for example) that there are appropriate "permissives" in the operating system to detect open valves, and ensure against a potential hazardous condition of uncontrolled steam supply in a shut-down situation.

 

[MJCronin]

cooper,

The small bypass line is typically installed on steam piping valves for a variety of reasons:

- Allows equalization of pressure before admission of flow
(a major advantage with large, hand-operated valves)

- Permits slow heat-up of piping, minimizing condensate slugs

- Lengthens life of large-valve sealing surfaces

The need for bypass valves on large valves is discussed in a chapter on steam piping in the "Piping Handbook" by Nayyar

My opinion only...

MJC