5 replies to this topic

[Deep24]

I am planning to install a horizontal centrifugal pump for transfer of water from a pit to a different location. Suction lift considered for the pump is -5 m maximum and 0.9 M minimum. I am installing a priming vessel (1.4M ID x 1M height, 2m3 volume) in the suction line for ease of water filling during start-up. Also I am considering a foot valve at suction line end (in the pit).

 

Now my question is - 1) Do I really need a priming vessel? 2) If the size of the priming vessel matters in the performance of the pump?

Pump Capacity is 1276 m3/h and discharge head 36.6 MWC.

 

Drawing of the pump and priming vessel is enclosed.

 

Pls help.

 

 

 

Attached Files

•  Capture.JPG   38.73KB   0 downloads

[astro]

Assuming you've correctly assessed your pump's suction performance along the lines:

https://www.cornellp...e-suction-lift/

and you've appropriately assessed the pump's NPSHr across its operating envelope, I would have thought if the suction line can be primed from the pump inlet back to the foot valve and forward through the pump casing plus a step to bleed air/gas from a high point in that system, then a vessel will just extend fill time.

 

Once liquid is flowing, the vessel doesn't do much. Could be wrong. Happy to educated.

[fallah]

I am planning to install a horizontal centrifugal pump for transfer of water from a pit to a different location. Suction lift considered for the pump is -5 m maximum and 0.9 M minimum. I am installing a priming vessel (1.4M ID x 1M height, 2m3 volume) in the suction line for ease of water filling during start-up. Also I am considering a foot valve at suction line end (in the pit).

 

Now my question is - 1) Do I really need a priming vessel? 2) If the size of the priming vessel matters in the performance of the pump?

Pump Capacity is 1276 m3/h and discharge head 36.6 MWC.

 

Drawing of the pump and priming vessel is enclosed.

 

Pls help.

 

Hi,

 

Using priming chamber could be a good idea to prime the pump suction for lifting in pump start up, but the configuration you provided doesn't probably work after starting up. Then it's better just one short line (with a valve along it) from beneath of the chamber would be connected to the top of the suction line at a point as close as possible to the pump, and the chamber being out of service with closing the valve after priming and before pump's start up.

[breizh]

Hi,

Consider this link about priming pot (design, installation very close to pump suction).

No need for foot valve, just a fish net to prevent to suck leaves, dirt i.e. no strainer, no manual valve before the pot, missing a sight glass or way to monitor the level in the pot.

Rule of thumb: volume at least equal to 3 volumes of the suction line.

BTW this is a big pump. You may have to think to divide the capacity using smaller pumps (reliability and capex).

you existing set up requires 1 pump in service and 1 spare installed compared to 3 or 4 smaller pumps including 1 spare in stock in warehouse .

https://www.munsch.d...cts/priming-pot

Good luck.

Breizh 

[Zauberberg]

Check also these + attachment.

 

https://www.pumpsand...ing-pump-issues

https://gopps.com/npsh-calculator/

https://www.ebaraind...n-suction-lift/

 

Attached Files

•  Suction Lift.pdf   1.38MB   12 downloads

[Dacs]

5 meters suction lift for me is to close for comfort.

 

I do hope you have looked at the NPSH of the pump in question. Is the water ambient or at elevated temperature?