maximum peripherical speed in centrifugal pumps

[sinectica]

where can I find a table with the maximum linear speed of the fluid handled, depending on the material of the pump case?

thank you so much, any contribution will be appreciated,

Marc

 

[checman]

sinectica
I am not sure if I understand your question but sundyne makes centrifugal pumps that run at high RPM (22,000 + rpm) They might be able to answer your question.

Regards checman

http://www.sundyne.com

 

[vanstoja]

I can't believe that there exist any pump casing material limitations on pumped fluid surface velocity so I doubt that any such table can be found anywhere. Casing material surface finish conditions might impose friction loss limitations and surface corrosion propensity could be another material-related performance or reliability determinant. What are you really trying to determine?

 

[sinectica]

Hello vastonja,

there are many factors to limit the speed. The more applied are based on cavitation resistance (for the impeller) and on abrasive resistance (for both impeller and casing). I found some casings of centrifugal pumps that handle fluids with SH2 dissolved in it, that really affect the casing, and the limitation for this pumps is the linear velocity of the fluid.
In the case of impellers, which I think should be very close for the casings, someone gave me this guide, maybe you find it useful:

Standard materials (125-150 Brinell), 80 ft/sec
Medium hardness (225-250 Brinell, such as 12 CR, 316ss work-hardened), 100
ft/sec
250-300 Brinell (17-4, Cd4MCu, Nitronic 60), 120 ft/sec
Special (Mn-steel, stellite 6 coat, hastelloy), 150 ft/sec

Hope it works,

thank you so much!
Marc

 

[vanstoja]

Doolin,J.H., 1986,"Judge Relative Cavitation Perils with Aid of These Eight Factors", Power Magazine, Oct.,pp.77-80 gives relative cavitation erosion rate data for centrifugal pump impellers that includes separate factors for BHN,Brinell hardness numbers (for martensitic stainless steels), rotational speed and impeller material. Relative erosion rates for BHNs from 220 to 480 vary nonlinearly by a factor of about 3.6. For rotational speeds from 2000 to 10000 RPM erosion rate varies by a factor of about 2. For eight metals ranging from aluminum bronze to mild steel, erosion rates vary by a factor of 8 with aluminum bronze at 1.0 and stainless steel at 2.0. These data are reported to come from Cooper,P. & Antunes,F., 1982, "Cavitation Damage in Boiler Feed Pumps", EPRI Symposium on Powerplant Feed Pumps and from Piersall,I.S., 1974, Cavitation, July, British IME Proceedings.
Other sources indicate that cavitation erosion intensity is proportional to impeller inlet tip velocity, U1, raised to a power exponent between 5 and 7. A threshhold U1 of about 65 fps (20 m/sec) for cavitation to begin has been cited in the literature.