×
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

Pump Inlet/Outlet Nozzle Erosional Effect
2

Pump Inlet/Outlet Nozzle Erosional Effect

Pump Inlet/Outlet Nozzle Erosional Effect

(OP)
I need to select an ANSI pump for a water treatment plant, with the following problem:

According to the Process data we have calculated, the pump differential and flow rate, we have to select a 1x1.5 pump (outlet x inlet nozzle diameters).

However, due to the nature of the fluid we are handling (water + suspended solids) and requirements of our client, our suction line is 3".

Then, in order to interconnect the pump with this pipe, a 3x1.5 reducer is required and the velocity in the reducer and inlet nozzle is too high (22 ft/s).

According to API14E, the velocity should not exceed an erosional limit (in this case 20.25 ft/s).

Also, this reducer introduces a high pressure drop (due to the kinetic and frictional terms).

We have tried to find a pump with bigger inlet and outlet nozzles, without success.

Is there any harm in the pump and/or these fittings if we maintain this or higher velocities?

Regards,

Alberto

RE: Pump Inlet/Outlet Nozzle Erosional Effect

The change in fitting size, even a drastic change, is pretty common between the suction line and the pump inlet/outlet nozzles that I've seen.  I've also wondered about this but given the pump vendor sizes these nozzles, in light of the potential pump capacity, I've essentially decided they know what they are doing.

As far as the NPSHR, that would also be included when they do their testing and post the NPHSR figures so I have not included the effect of that reducer in my NPSHA calculations.  It's a good question though.  One other reason I don't include the reducer is that when I do these calculations, it's in the early stages of engineering and we have no idea what the pump suction nozzle is for a diameter.

RE: Pump Inlet/Outlet Nozzle Erosional Effect

td2k is right, one thing I would add is to make sure your operating ranges for the pump are within the range for the pump.  If the manufacturer doesnt have them available for you, stay +20 and - 40 percent of bep.  I have seen people design using the pump outside of its range and they get extreme flows, which are beyond the nozzle design for the pump as designed by the manufacturer.

BobPE

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 New World of Thermoplastic Manufacturing
Digital-direct thermoplastic manufacturing offers exceptional quality, opens the door to novel design parameters not possible with injection molding while also bypassing the long lead time and up-front investment in injection molding tooling, offering a better total value proposition. Download Now
White Paper - Strategies to Secure Connected Cars with Firewalls
White-hat hackers have demonstrated gaining remote access to dashboard functions and transmissions of connected vehicles. That makes a firewall a vital component of a multilayered approach to vehicle security as well as overall vehicle safety and reliability. Learn strategies to secure with firewalls. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - What is Generative Design and Why Do You Need It?
Engineers are being asked to produce more sophisticated designs under a perfect storm of complexity, cost, and change management pressures. Generative design empowers automotive design teams to navigate this storm by employing automation, data re-use and synchronization, and framing design in the context of a full vehicle platform. 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