Viscosity 3

[aiwa7777]

What is the practical / maximum viscosity limit for centrifugal pumps ?
Please advise.
Thanks

 

[SNORGY]

Figures 1.52 and 1.53 in the publication:

ANSI / HI 1.1-1.5-1994
American National Standard for Centrifugal Pumps
for Nomenclature, Definitions, Application and Operation

suggests that you can apply correction factors for performance with viscosities up to 2200 cSt for small pumps (Q<=100 USGPM @ BEP) and about 4000 cSt for larger pumps. One might infer that these represent industry-accepted practical limitations.

Also, I think I read somewhere that the affinity laws for centrifugal pumps start breaking down when viscosities exceed 50 cP. Might have been in the Hydraulic Institute Standards.

Regards,

SNORGY.

 

[25362]

Sulzer in its Centrifugal Pump Handbook (Elsevier) says:

The economical duty limit for centrifugal pumps is about 150.10^-6 m²/s. Use of a centrifugal pump is possible up to about 500.10^-6 m²/s. but a higher NPSH must be made available for this higher viscosity. Channel impellers and torque flow pumps allow higher values (800 to 1000.10^-6 m²/s), depending on size and type.

BTW, 1 cSt = 10^-6 m²/s.

 

[ione]

I think ANSI/HI 1.1-1.5-1994 has been now superseded by ANSI/HI 1.1 1.2:2008 ("Rotodynamic (centrifugal) Pumps For Nomenclature And Definitions").

You might also want to consult ANSI/HI 9.6.7 (“Effects of Liquid Viscosity on Rotodynamic Pump Performance"), which presents a revised procedure and equations to predict pumps performance or give a shot to this handy calculator:

http://www.lightmypump.com/viscosity/Viscosity.html

 

[BigInch]

Pump's viscosity limit is seldom the true limitation, unless your pipe is only 1 foot long.

"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.

"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[SNORGY]

ione:

I am old. I stopped collecting stuff years ago when it started to hurt too much to bend over to pick things up.



That said, I should (and will) endeavour to get a copy of the more recent publication. Thanks for letting me know.

Regards,

SNORGY.

 

[aiwa7777]

I would like to thank everyone who provided their valuable input.

 

[rmw]

Snorgy,

If you find a large print version, post back.

rmw

 

[BigInch]

Snorgy, 500cp not 50

rmw, It'll probably be in "mimiograph media".

"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.

"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[SNORGY]

Thanks BigInch.

I know I read "50 cP" as a magic number somewhere. I'll have to dig around a bit. HIS FAQ's suggests 1000 SSU, closer to 200 cP.

rmw:

http://estore.pumps.org/Centrifugal-Pumps-C7.aspx

Regards,

SNORGY.

 

[Compositepro]

These centrifugal pumps can handle up to 100,000 cP.

http://www.discflo.com/images/stories/pdf/generalbroch.pdf

 

[d23]

aiwa7777,

The original question could be a little misleading. I would be hesitant to answer unless I knew the head and flow required. Do you have a small pump that only requires 10 GPM with 10 feet of head or are you trying crude oil pipeline pumps?

Knowing a little more about the application would help. Economics ultimately should determine the answer.

D23