Tank filling-bottom or top-rotary pump
Tank filling-bottom or top-rotary pump
(OP)
From the following website,
http://www.mcnallyinstitute.com/12-html/12-03.html
"If I wanted to fill a tank with a centrifugal pump I would fill the tank from the top because that is the only way I could keep a constant head on the system and keep the pump close to its best efficiency point. If I were using a rotary pump, I would fill the tank from the bottom because the pump would be using less power during the filling process (power is foot pounds or head times capacity)"
Question: Is above statement about rotary pumps is correct? If yes, could someone care to explain.
Thanks,
http://www.mcnallyinstitute.com/12-html/12-03.html
"If I wanted to fill a tank with a centrifugal pump I would fill the tank from the top because that is the only way I could keep a constant head on the system and keep the pump close to its best efficiency point. If I were using a rotary pump, I would fill the tank from the bottom because the pump would be using less power during the filling process (power is foot pounds or head times capacity)"
Question: Is above statement about rotary pumps is correct? If yes, could someone care to explain.
Thanks,





RE: Tank filling-bottom or top-rotary pump
RE: Tank filling-bottom or top-rotary pump
RE: Tank filling-bottom or top-rotary pump
RE: Tank filling-bottom or top-rotary pump
It also ignores any beneficial impact from a dip pipe in a syphon effect to avoid spraying product into a tank from a high point inlet.
Also if the flow rate was variable, then the centrifugal pump would probably fill it faster as it would flow more product at the start than the finish whereas a rotary pump would be more or less the same flow regardless of tank level.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Tank filling-bottom or top-rotary pump
As we know, the operation point is at the intersection of the pump curve with the system curve. Varying the level of the tank might or might not change substantially the system curve. If the operation point with the tank completely filled is very close to the operation point when the tank is completely empty, then there isnt much difference filling it by the top or by the bottom. But it will depend on both system curve and the pump curve. You will have to draw these curves to get to some conclusion.
When we talk about reciprocating pumps, all of that doesnt really matters. So I would recommend you to fill the tank by the bottom, so it would spend less.
cheers