2 replies to this topic

[ankur2061]

Dear All,

 

Pump slip for rotary PD pumps is a phenomena where the pump theoretical displacement capacity is reduced due to a combination of decrease in viscosity and increase in discharge pressure.

 

I would like to know the method for calculating the decrease in capacity of the pump for a rotary 2-screw pump which has been specified for pumping 2 different products with different viscosities. Let us say that one product has a viscosity of 380 cSt and is the design case specified to the pump manufacturer for a given differential pressure and flow rate. The pump is a fixed speed pump. Now the same pump is required to be used for pumping another product with a lower viscosity of 22 cSt.

 

How do I calculate the flow rate for the second case with the reduced viscosity considering "slip" playing a role in changing the pump capacity? Are there any formulas or equations for doing such a calculation?

 

Regards,

Ankur.

 

 

Edited by ankur2061, 14 February 2015 - 04:07 AM.

[Napo]

Dear Ankur,

 

Please you can review the Hicks, Standard Handbook of Engineering Calculations, 4th edition, p.3-392 and 3-393.

 

I hope help you.

 

Regards,

 

Napo.

[breizh]

Ankur ,

Let you consider this document with some data  . Probably the answer should come from the vendor for a specific equipment..

 

Hope this helps

 

Breizh