×
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

Could you tell me what going on ???????????????

Could you tell me what going on ???????????????

Could you tell me what going on ???????????????

(OP)
Dear sir
 Please be advised pump operation and the result after our supervisor went to your site to investigate and test during June 14-15, 2001 as below :
June 14, 2001    :    Before start the pump, we open valve at port no. 5 for venting and find liquid foaming is occurred all time.  We took 30 minutes time until a little bit foaming is found.  Then we start the pump.  Operating data is as below :
    -    Pressure at suction drum is 15-20 PSI.  Needle of pressure gauge is swing all time.
    -    Suction pressure which pressure gauge is installed at strainer is 8-10 PSI.  Needle of pressure gauge is swing all time.
    -    Discharge pressure is 290-300 PSI.  Needle of pressure gauge is swing all time
    -    Current is 22 Amp.
    -    Pressure of condensate surge drum (Destination drum) is 285 PSI
    -    S.G. of liquid is 0.754
We found the pump can't pump by observation liquid level in suction drum doesn't decrease, and feel hot when tough on suction piping and pump casing.  Then we vent the pump again by opening valve at port no. 5, and find gas blow out.  After that we started the pump, and the result still the same.  We find pump can't pump.  Then we bring sample liquid to fill up on small vessel, we find that this liquid is easy to become foaming.  It become foaming by shaking the vessel.
 June 15, 2001    :    We open suction valve to allow liquid come into suction piping, and pump casing for 1 night, then we vent at positions we expect it may occur air block i.e. strainer, pump casing drain, seal port no. 5, discharge line before discharge valve and discharge pressure gauge.  For this venting, it take about 1 hour to make sure that no any gas in suction piping and pump casing.  After we start the pump, and operating data we record is as below :
    -    Pressure at suction drum V-3610 is 4 PSI
    -    Suction pressure which pressure gauge is installed at strainer is 8-9 PSI
    -    Discharge pressure is 290-300 PSI
 We find the pump can pump for a short period (only 15 second).  It is observed be decreasing of liquid level in suction drum, after that the pump can't pump, although we adjust discharge valve decrease.  During pump operate, we find suction piping, pump casing, and discharge pipe are cool, and water-dropped is found on piping.
 Then we vent piping and a seal port no. 5 again, and start the pump.  For this time, we open part no. 5 all time the pump operate.  It is find foaming is occurred all time, and the pump can't pump.
 For above mentioned symptoms, we expect that your liquid is easy to vaporize.  Only a little bit of pressure or temperature is changed.  It cause your liquid become foaming, or vaporized.  So it occur gas inside the pump casing, and the pump can't pump as final.

RE: Could you tell me what going on ???????????????

What fluid are you pumping, hydrogen peroxide?

RE: Could you tell me what going on ???????????????

No ! just light hydrocarbon (mixed)
Do you know this problem came from not enough NPSH available or not?

RE: Could you tell me what going on ???????????????

The fluid you are pumping is at the saturation point.  The fact that it pumped for a while says that the pump needs whatever height in the suction separator where it stopped.  Yes it is a strong possibility you have an NPSH problem.  You need to check the suction line for pockets, blockage, and if the starining is blocked.  Good luck

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

White Paper - The Evolving Landscape of Commercial Battery-Powered Trucks
What’s driving the evolving landscape of truck electrification? What are the barriers, motivators and strategies for accelerating the electric transition? What insights and resources are available for today’s design engineers working to achieve industry disruption and evolution? For answers to these and other pertinent questions, read this white paper. Download Now
eBook - Rethink Your PLM
A lot has changed since the 90s. You don't surf the Web using dial-up anymore, so why are you still using a legacy PLM solution that's blocking your ability to innovate? To develop and launch products today, you need a flexible, cloud-based PLM, not a solution that's stuck in the past. 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