Pump curve doesn't cross system curve 1

[EngMecBra]

Hi everybody,

Process team have informed me a rated head of 41m, then I have selected a pump.
Now I have been informed that the new head is only 15m.
The problem is that the pump has already been bought! Neither with minimum diameter impeller the pump curve crosses new system curve!
What kind of problem will occur in operation? Will these pumps operate?

See attached drawing.

Tks!

Rodrigo Alves

 

[QualityTime]

The other thing that can be looked at is if a different impeller can be installed in the pump casing. There are many different impellers that can be installed in a pump casing.

 

[Artisi]

Must be a very pressing problem, the OP hasn't been returned since the initial post - maybe suffering information overload.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[BigInch]

That rarely concerns us.
We don't stop until the questions stop.. sometimes not even then.

Independent events are seldomly independent.

 

[Artisi]

A bit like the opera ain't over till the fat lady sings.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[SMIAH]

He installed VFD, a control valve plus a recirculation line and changed pump.

Problem solved.

 

[BigInch]

Just in time to find out that the new reduced head system curve was the result of somebody not considering connection backpressure at the end of the downstream pipeline.

Independent events are seldomly independent.

 

[EngMecBra]

Tks for all and sorry for late answer!

I have read all posts, but I don't have any news from pump manufacturer, e.g. new curves considering different speeds and a smaller impeller.

Soon I will bring information to discuss more with you.

Best ragards