(No subject)

From: <Arif>
Date: Sat Nov 16 2002 - 12:12:00 EST

I have a small project to modify control of exiting pumping system which trasfer fluid from one tank(50 feet dia) to other tank(50 feet dia). The level of source tank is only variable at 5 feet however the discharge tank level varies from zero to 45 feet. The first pump starts automatically at particular level(70 %) in source tank and the second pump starts automatically if source tank level goes high by 3 feet.The rated flow rate for each pump is 500 GPM at 50 psig discharge pressure.

The problem is that if manual valve at the discharge of pump is throttled initially (with zero level in discharge tank) the pump will not not be able to pump if discharge tank level rises to 45 feet. And if discharge valve is adjusted for full level in discharge tank , the pump will operate way beyond it rated flow when the discharge tank level is low..
The problem is that there is no space to install flow orifice.

I am thinking to add a control valve which will operate based on level transmitter of source tank and discharge tank.That is if source tank level goes to 70 % and if level in discharge tank level is low , the valve will open partially. The valve will open gradually if discharge tank level is rising.It means that valve opening wiil be based on level of discharge tank.But the valve will have to be adjusted again automatically when second pump starts.
Can I get some good ideas for the given problem

Regards,
Arif Patel

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