×
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

PSV Testing - Back pressure (Bellows)

PSV Testing - Back pressure (Bellows)

PSV Testing - Back pressure (Bellows)

(OP)
Hello All,
I'm conducting a back-pressure test on a PSV fitted with bellows, testing at 30psi (air) as per ASME Viii.
The valve manufacturer tag plate shows the set pressure of the valve, but also the back pressure, in this case 22psi for the latter. I’m assuming that the back pressure stated on the tag plate means the test pressure, but it’s not something I usually see on a tag plate. The stated back pressure could also imply that it has been sized for an application with 1.5bar back pressure, either built up or superimposed.
ASME Viii states that the minimum test pressure for the second cavity of the PSV should be 30psi. Is that test pressure sensible based on the fact the tag plate shows 22psi for back pressure (this could be for sizing applications or the manufactures test limit for their bellows).
It’s a small testing anomaly, but bellows are quite fragile so I don’t want to kill them!

Any insight on this would be much appreciated.

Thanks in advance

RE: PSV Testing - Back pressure (Bellows)

Hi.

Your question would most probably been answered by now, if you had posted it in the specific SRV Forum "Safety Relief Valve Engineering (PSV). Please note for future.

The test you reference, is that to test the integrity of the bellows ?ie., to ascertain if the bellows are not ruptured/split/damaged? If so, you will pressurise the outlet of the SRV and see if there is any leakage out of the bellows vent. 30 PSIG is normal for that test, though I would refer to the manufacturers instructions. Please advise if you are conducting a different test, as other comments apply.

The back pressure you find on the nameplate, is the back pressure the SRV will be seeing in service. It is used for sizing and selecting the SRV. It is not a test pressure.

Hope that helps.

Per ISO, only the term Safety Valve is used regardless of application or design.

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

eBook - Mastering Tolerances for Machined Parts
When making CNC machined parts, mastering tolerances can be challenging. Are general tolerances good enough? When does it make sense to call out for tighter tolerances? Do you need a better understanding of fits, datums, or GD&T? Learn about these topics and more in Xometry's new e-book. Download Now
eBook – How to Choose the Correct Corrosion Testing Method
When designing a metal component, engineers have to consider how susceptible certain alloys are to corrosion in the final product’s operating environment. In a recent study by NACE (National Association of Corrosion Engineers), it was estimated that the direct and indirect costs of corrosion in the United States is approximately 6.2% of the GDP. In 2016, that cost exceeded $1 trillion dollars for the first time. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close