×
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

API 671 coupling , hydraulic fit , maximum pressure .
2

API 671 coupling , hydraulic fit , maximum pressure .

RE: API 671 coupling , hydraulic fit , maximum pressure .

I would never expect anything to explode. If you keep increasing the pressure, one of three things are likely to happen. The coupling hub will pop off, some fitting in the hydraulic system will fail by leaking, or the o-rings between the hub and the shaft will blow out. I would pump it up to maximum rated pressure and then add heat (steam is better than flame). I would increase the pressure above the maximum rating by 10% if necessary. If it does not pop, you are going to have to cut it off, which is not an easy thing to do.

Johnny Pellin

RE: API 671 coupling , hydraulic fit , maximum pressure .

2
JJPellin is correct, the hub will not explode. What will happen is it will yield at the weakest point which will compromise its usability when re-installing. If you have a coupling drawing we can provide you the calculation of where this point is. The tough thing about hydraulic fit hubs is that they are very easy to over squeeze on to the shaft during install. This has to do with the ratio of surface area available during install vs during removal. During removal there isn't a gap for the fluid to flow so the pressure required to remove is much greater then what is required to install, if this isn't followed, the hub will be on so tight it will be very difficult to remove with out yielding.

The maximum pressure rating is typically calculated on install (when pressure vs surface area is greatest), so you have much more then that on removal, but it may be difficult to control the pressure once it pops. So you actually yield it after it breaks free when that hydraulic fluid rushes in at a pressure greater then maximum rating.

When it comes to couplings we are always here to help.
WWW.PSCCOUPLINGS.COM

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