1 reply to this topic

[ayush]

What is a VS6 pump? where and why it is used? what are its advantages and disadvantages? What are the calculations involved in selection of this type of pump. what all needs to be taken care while evaluating the vendor offer

[Art Montemayor]

Ayush:

 

I don’t know what experience you have with centrifugal pumps, but you should do some serious research on them simply by using the Google search engine.

 

Twice, in the last 53 years, I have come across a centrifugal pump application that revealed the often-imagined nightmare of a project engineer where a centrifugal pump had to be installed in a pit below grade in order to satisfy the required process NPSH conditions.  This can be an embarrassing event for many design and project engineers – one that can threaten your successful career.  A double casing VS6 type of vertical centrifugal pump can rescue a design engineer who forgot to fill in a detailed data sheet for a process pump with a minimum of NPSHR.  It requires to be installed vertically, but its inlet and discharge flanges are at grade.  The term “double casing” is literally that.  It has a casing around the string of impellers that is used as an annulus section that serves to feed a positive head of liquid to the first suction impeller located below grade.  This configuration – albeit unconventional – serves to give a positive head to the impellers.  Refer to the attached FlowServe literature for a description and information.

 

The advantages and disadvantages for this type of pumps are fairly obvious.  Any calculations required for pump selection are the same as you would do for any other pump – the same work effort applies to this pump as to any other pump when doing an evaluation.  You still require the pump calculations for NPSH, the system curve, all necessary hydraulics and instrumentation as well as a detailed API 610 data sheet.  That’s what we are paid for.

 

 Type_VS1_and_VS6_Vertical_Turbine_Pumps_Wet_Pit_and_Double_Casing .pdf   4.67MB   76 downloads