differenc between flanged-end vs through-conduit 1

[elmio]

Good Morning All

I am really new on this field and the first thing I have been doing reading API 6D. Does anybody could help me what is the difference between the following sentence:

Full-opening flanged-end valves shall be unobstructed in the fully opened position and shall have an internal bore as specified in... There is no restriction on the upper limit of valve bore size.

Full-opening through-conduit valves shall have a circular bore in the oburator that allows a sphere to pass with a nominal size not less than that specified in...

Many Thanks

 

[BigInch]

Great! Welcome to the pipeline business.

API 6D, as you already know, defines criteria for pipeline valves and one of the things that is often done to clean the inside of pipelines is to run a pig through them. Any valves in a pipeline must then be capable of passing pigs, "dumb" cleaning pigs, spherical rubberized things, or elongated series of brushes, similar to a bottle brush, or what can be quite long "intelligent" inspection pigs. As all of these pigs are sized to fit snuggly in the pipeline, it wouldn't do to reach a valve that did not have the same "hole size", or internal bore, as the pipeline itself, as getting stuck inside a valve that could be a hundred miles away from an outlet would be a royal PIA. "Full-opening through-conduit" thus refers to an internal valve "hole size" being of a diameter nearly equal to, if not slightly greater than, the pipeline's internal diameter so as to allow unrestricted passage of these pigs.

Of course there is a practical limit to the internal bore of a valve, as it cannot possibly be larger than the OD of the valve's end connections to the pipeline.

From "BigInch's Extremely simple theory of everything."

 

[elmio]

Thank you BigInch!

I really appreciated!

Elmio