Vertical Turbine Pump - Total Head Calculations

[MeckMan]

For calculating the Total Head for a horizontal centrifugal pump, we need to reference liquid levels in suction and discharge tank relative to the centerline of the pump impeller. This I know.

But how about a vertical turbine pump?

I believe that the discharge tank level should be in reference to the discharge flange of the pump. Is this true?

The part I am having most difficulty with is the suction tank level. To which part of the pump do we need to reference? The discharge flange, the impellers at the bottom of the pump suction column?

Thank you in advance.

 

[kenelms]

The important point to take note of is that proper submergence of the pump impeller takes place within the pump pit. Submergence requirements for pumps vary with size of pump and also its speed of rotation. As a rough working guide -good practice dictates that for eye velocities of about 20 ft/sec and peripheral velocities of about 65ft/sec-the required submergence should be from 2 to 5 ft depending on the size of pump. Manufactureres usually show diagrams for both wet and dry well installations.

 

[MJCronin]

Meckman,

Get a hold of the "Goulds Pump Manual" (GPM6 or GPM5) and see the discussion in section 7B-7.

Your "specified pump head" should be the difference in elevation from the "drawdown level" of the sump to the destination tank. (The drawdown level of the sump is defined as that level that will occur when the pump or pumps are in operation... It is always less than the static level of the sump) Use of the elevation of the top impeller in the pump would be a good number.

A vertical turbine pump sales rep can help you with more details....

Also, !!! do not forget that the pump exerts a downward force on the supporting structure when operating. The supporting steel (or concrete) should be designed for both the deadload and the thrust load acting at the same time.

MJC