×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

Noise and vibration when we open a valve

Noise and vibration when we open a valve

Noise and vibration when we open a valve

(OP)
greetings;
A fine filter receives the oily water pumped through a Flow valve (10 inch, 370 m3/h, 07bar).
We use the by pass in case of the FV is not available (10" with manual globe valve), when we open the bypass valve (whether it is the opening) an unbearable noises and vibrations persist.
your suggestions to solve this problem please.

RE: Noise and vibration when we open a valve

Replace the globe came with one which has the same CV characteristics of the main control valve.

Why is the main control valve" not available"?

We like new people but do you not have anyone else to ask where you work?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Noise and vibration when we open a valve

Just to get the basics of out of the way, is your globe valve oriented correctly relative to flow?

RE: Noise and vibration when we open a valve

1/ Comments above.
2/ Find and partially close any valve downstream of the bypass globe valve. This will increase bypass outlet pressure => reduce pressure drop => reduce flashing&cavitation => reduce noise&vibration.
3/ Insert a flow orifice downstream of globe valve. The same effect as above.
4/ Replace the manual globe valve with a manual CV the same design of wet part as that of FV.
5/ Find and employ a qualified process engineer. This will reduce uncertainty, risks and expenses in future.

RE: Noise and vibration when we open a valve

Hello,

Seeing the snip of your P&ID, (engineered) control valve 8"-300# and (a normal globe) bypass valve 10"-300#.
Short term solutions is to open bypass valve directly to approx. 25% and tweak the position (smaller or bigger) that meet your flow requirement. However please note that the 'last' position should be at the position where fairly minimum to no vibration. This is a best practice that is loooong forgotten by most (new) operators. simply open it from fully close 0% > 1% >> 2% and so on to find the right flow spot is a recipe for disaster.

Not a control valve expert myself, but I think your bypass Cv is more than 1.5-2x Cv of control valve. meaning if operating position of control valve let say 25%, then in the absence of main control valve, in order to meet the same flow condition, then bypass valve will only requires less than 10% of its open position. The smaller the opening the bigger the velocity and kinetic energy.

Vibration is a combination of velocity and kinetic energy. From Energy Vibration Institute, the threshold is 460kPa.
Your control valve might be looking something like this e.g. MarkOne with integrated spindle/plug and streamline Plug profile.


and your manual bypass valve is something like this. Spindle and plug is not integrated, Plug has flatter surface shall compared to control valve. With the right kinetic energy and velocity, there will be vortex shading after the Plug which vibrates the Plug and essentially also vibrates the spindle. Risk of gland burst/leakage.


You can calculate this by simple excel. Data needed are flow, specific gravity of medium, upstream/downstream pressure, Cv of bypass valve, spindle travel (with relation to opening area between seat and Plug). Just iterate the value based and you will find the minimum opening position.

Good luck,
regards
D

RE: Noise and vibration when we open a valve

(OP)
Thank you Mr Danlap for this helpful explanation

RE: Noise and vibration when we open a valve

You're welcome youssouf,

I feel the necessity to tell you that even without doing calculation, it seems like you have an oversize bypass line.
Long term and more fool proof solution is to engineer the bypass valve aka control valve with a handwheel.
If Cv of the main 8"-300# control valve is the reference, then there might be a limitation for 10"-300# bypass valve to be within the same range of that Cv. Expect a respond from valve supplier that you might need to use also an 8" bypass valve. Or maybe even 6"

Regards
D

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! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. 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