×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Open or closed bonnet?

Open or closed bonnet?

Open or closed bonnet?

(OP)
Can anyone tell me if a bellows PSV with a vent pipe is classed as an OPEN or CLOSED bonnet valve?

Kind regards

RE: Open or closed bonnet?


The general understanding in my personal opinion (not refering to any standard):

Open bonnet: any bonnet that will expose /let (leaking) fluid (from stem sealings) or other sources escape to the surroundings.

Closed bonnet: any bonnet that under normal operational conditions will keep the fluid inside the valve or bonnet, even if stem sealings etc. are defect.

A bonnet with a vent hole is then not a closed bonnet, if the vent hole is not properly (permanently?) sealed, and constructed to be sealed under all operational conditions.

RE: Open or closed bonnet?

In the event of a bellows failure, process fluid will escape from the bonnet vent port. From the above descriptions, this then classes it as an open bonnet. If, however, you stick to safety valve terminology, then a bellows valve is closed bonnet. With respect to safety valves, open bonnet means large areas of the spring are exposed and process fluid will leak to atmosphere through the bonnet. The bellows will prevent this in normal service.

RE: Open or closed bonnet?

I don't currently have full internet access, but Spirax Sarco publish some very informative safety valve information and terminology descriptions on their website and are well worth a look.

RE: Open or closed bonnet?

(OP)
Thanks guys, i started another thread on a different board with the same question.
But then i couldn't find the thread and thats why i asked here.

It seems people really do have different opinions on this and well, we can't all be right can we.
Some seem to think its open, some closed.

http://www.eng-tips.com/viewthread.cfm?qid=371618

Thanks

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources