3 replies to this topic

[kamleshbagul]

We need to study the feasibility of a centrifugal pumps for increased capacity demand. As per field feed back; we came to know that even after keeping the discharge valve fully open; the time required for transferring pre-defined quantity of feed is very high. which means the pump is running below duty point. Hence during our initial investigation we land up in conclusion that the existing discharge line size (2") is under designed; leading to heavy pressure drop across the pump discharge nozzle and destination. This could be the reason of larger back pressure at the pump discharge; causing the low discharge flow (even after discharge full open).

 

Hence; we are proposing to increase the discharge line size. 

 

As per discussion with vendor we got to know that he have supplied the pump assuming water as pumping fluid. We want to pump Potassium silicate which has specific gravity as 1.364 and viscosity 260cP. Moreover their also a leakage in the seal ( as potassium silicate with 46% solid is an abrasive material)

 

 

Please let me know whether we can use same pump for increased capacity demand??  

[breizh]

Hi ,

Please consider to prepare a specification sheet with relevant information and submit it to vendor .

You found already plenty of issues and gaps , nature of the fluid, viscosity, abrasiveness of the product, etc .

good luck

Breizh

[vaibhav]

hi bagul

 

basic information we should furnish to pump vendor at the time of proper selection of the unit .

 

keep in mind that pump performance or testing fluid is water unless otherwise specified.

 

regards

VP

 

 

[Amit J]

Hi Kamlesh,

 

Your problem is multi faceted. I will try to put some light on issues.

 

1. Every Pump manufacturer designs pump for Water service & establishes performance curve for water service. But if you have specific demand of service fluid , then performance curve can be established for desired service fluid. Check if the pump mentioned is used for same service since beginning. Also check whether actual fluid data was shared with vendor at the design phase and if that data is consistent with your current service fluid composition.

 

2. If you found that fluid is abrasive , then vendor only can suggest appropriate seal plan.

 

3. If you find that discharge flow is less than desired one then there could be multiple issues:

a) Pump discharge line is limiting.

b ) Pump motor is limiting which may not be providing sufficient power at such high viscosity to push the fluid to destination.

c) Since your fluid contains solids, there may be deposition of solids at certain pipe segments (viz. elbow, Tee, valve etc) , which is not allowing fluid to pass and creating excess pressure drop.

 

4. you can evaluate if you can increase RPM of pump which will help to increase capacity as per affinity law, when impellar remains same.

 

5. If impellar of large diameter can be used, same can be replaced.

 

I hope this can help to analyse problem further and reach solution.

Edited by Amit J, 07 February 2018 - 07:25 AM.