×
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

PD pump Shaft bend what could be the causes ?

PD pump Shaft bend what could be the causes ?

PD pump Shaft bend what could be the causes ?

(OP)
I received a complaint of new oumo supplied that it shaft bend and This application is pumping light oil, I would like to kbow what caused the pump's shaft to bend ?

And woul that be possible
To straighten the pump's shaft and would That be an issue of lower flow than normap after repairing.

RE: PD pump Shaft bend what could be the causes ?

The most likely cause is that the installer dropped the pump on the shaft, or dropped something heavy on the shaft.

A machinist might be able to straighten it to within the coupling's misalignment range.
That operation, and any remaining imbalance, will probably shorten the bearing life.

None of that should affect the flow.


Mike Halloran
Pembroke Pines, FL, USA

RE: PD pump Shaft bend what could be the causes ?

I think you might be able to bend some shafts, by ingesting something non-fluid and incompressible into the cylinder.

RE: PD pump Shaft bend what could be the causes ?

Long thin rotor stored long time horizontally without rotation might bow. It can also be result of poor manufacturing, possibly residual stresses lead initially straight shaft to bow

Shop may be able to straighten with heat applied inside the bow. I'd look for a shop I trust and ask them whether they think they can do it successfully on this shaft

=====================================
(2B)+(2B)' ?

RE: PD pump Shaft bend what could be the causes ?

To intelligently reply to this post, it is required to know what type of PD pump you are referring to?

Gear?
Twin Screw?
Three Screw?
Reciprocating?
Sliding Vane?
Double Lobe?

If the pump performed well on the test stand, but the customer is complaining about a bent shaft, I would expect that the customer closed a valve on the discharge of the pump causing very, very high pump shaft torque or a high moment on the shaft. Quite often, operators do not understand how these pumps truly operate.

RE: PD pump Shaft bend what could be the causes ?

(OP)
Hi theron this is internal gear pump

RE: PD pump Shaft bend what could be the causes ?

If torque overload could cause bent shaft (I havne't heard of it, but that doesn't say much), then a logical followup question would be: does the system have unisolable relief valves on pump discharge. (That's the norm from the limited set I have seen).

Another possibility to consider would be unusual heating of shaft during operation.

=====================================
(2B)+(2B)' ?

RE: PD pump Shaft bend what could be the causes ?

Maybe foreign material being sucked through the pump

=====================================
(2B)+(2B)' ?

RE: PD pump Shaft bend what could be the causes ?

Wait a sec: The goo you're pumping starts out at 30000cp in the tank, and >solidifies in the heat exchanger downstream<, and you're wondering why the shaft bent?

Or did I misunderstand something from your other related discussion?


Mike Halloran
Pembroke Pines, FL, USA

RE: PD pump Shaft bend what could be the causes ?

(OP)
Hi mike, thats my other thread and nothing to do with this shaft bend. I just would like pointed out some possibility of shaft bend on the pump.

Thanks for the inputs

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