Side-By-Side Vertical Turbine Pumps - Min Center Distance 9

[patspr]

I have an application that requires the installation of two side-by-side vertical turbine pumps. Under worst-case condiditions, both pumps will be operating at full load simultaneously. The pumps are identical - 725 gpm at 120 ft TDH. Can anyone provide a resource for recommendation on minimum center-to-center spacing for this type of application. I'm worried about cavitation problems caused by vortexing.

Thanks in advance.

 

[patspr]

I forgot to mention . . . the fluid is water.

 

[eddieng27]

Good, you need to be concerned about cavitation and vortexing !! Often pump manufacturers will have a design guide (usually far to the back - Marsten Pumps(?) I think has a good one) for the the intake design. The Hydraulics Institute and pumping station design books should also provide some good guidance; but consult the manufacturer for your specific pump. Just spacing between the columns is generally not enough and you'll likely need baffles if not more specific chambers for the suction intakes. Often suction cones and or vanes are necessary/ recommended. Once you've got the intake design figured out, don't forget to review the spacing as it concerns operations and maintenance access.

 

[rmw]

Without looking to verify my memory, I think Cameron's Hydraulic Data has just such a section.

rmw

 

[Artisi]

Cavitation is a completely different animal than vortexing and needs to be addressed as a seperate issue. Cavitation is a function of inlet pressure and the manufacturer can supply this information to you, and any reputable manufacturer wil also advise you on intake positioning in a pump forbay. Otherwise do a search on the net for "vertical pump intake design" I'm sure there will be plenty there for you.


Phitsanulok
Thailand

 

[Artisi]

Just had a quick look for you - try the following

http://www.gouldspumps.com/pag_0007.html

Phitsanulok
Thailand

 

[bingopin]

Try the Hydraulic Institute.

http://www.pumps.org/content_detail.aspx?id=2112&ItemId=2112

 

[BigInch]

Artisi, I had seen the ref you mention for basin design, but I had forgotton about it. Reviving the link is worth a star.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[rmw]

If you can get ahold of an old Byron Jackson Pump design manual it has a comprehensive section on this topic.

rmw

 

[thewellguy]

American Marsch pumps (formerly J-line aslo has info at
american-marsh.com

 

[patspr]

Thanks to all who replied. The information was extremely helpful.

 

[whieber]

Here are a few thing to do to prevent Vortexing. And remember that vortexing is caused by inlet velocity so anything you can do to minimise inlet velocity will help.

These suggestions were obtained at

http://www.mcnallyinstitute.com/14-html/14-12.htm

* Place a cone under the bell.
* Use diffuser screens.
* Use floating rafts around the pump column to break up the vortices.
* Float large spheres on the surface to break up vortices.
* Move the pump away from the wall.
* Increase the size of the inlet piping.
* Reduce the inlet velocity by spreading the flow over a larger area, or change the direction and velocity of the flow by the use of baffles.
* Eliminate the separating wall between pumps.
* Keep the inlet flow to the pit below 2 feet/second (0.7 meters/sec)
* Keep the flow in the pit below 1 foot/sec (0.3 meters/sec)
* Any type of a logical flow straightener will help reduce velocity.

Walter Hieber
PIB, INC. -

http://www.thepumpbox.com