5 replies to this topic

[Vegeta]

Dears,

If we have a pump suction piping that has vertical Pockets, why can't we operate the pump with a liquid level in the source tank that is below the that vertical Pocket based on siphoning effect? what if the operation is intermittent? is there a rule of thumb of how low you can go below the elevation of the vertical pocket?

I appreciate your help...

[Bobby Strain]

And, what exactly is this vertical pocket you refer to? Pictures/sketches are good to convey information.

 

Bobby

[fallah]

Vegeta,

 

Please provide us with a simple sketch of the system you described...

 

Apears with vertical pocket you actually mean vapor pocket in suction line due to a high point....which is mostly unacceptable in pump's suction line configuration...

[Vegeta]

Attached is what my questions are about.

Attached Files

•  001.jpg   44.66KB   4 downloads

[Chemitofreak]

Hi,

 

Generally it is a good engineering practice to avoid high point, as vapour might be trapped in it and this can lead to subsequent cavitation of the pump.

 

If you cannot avoid the high point due to plot plan or any other issue, ensure that you have adequate NPSH for the pump and make it a point that the suction line is fully flooded with pumping liquid before starting the pump. Vapour/Gas shall be vented from the high point before pump start-up.

 

Revert in case of any query. 

[fallah]

Attached is what my questions are about.

 

Vegeta,

 

That is what I did guess to be...

 

The configuration you shown cannot be accepted at all; especially if the liquid level decreases below the high point...because probable air/vapor pocket will affect the pump performance negatively and might be leading to the pump cavitation and subsequent damage...

If  anyway you have to consider such configuration an automatic air vent at the high point might help to reduce the intensity of the concern...