Pumping crude at 7500 gpm. Need low NPSHr pump (<10ft). Vertical turbine does not work because of sump depth. Also, need to protect against storm surge because client is in hurricane area. Ideas?

David,
What is your differential head?
Best,
Denny Fegan
Powerdyne Consultants

164 feet. Thank you for your response.

David,
Your options are:
1. Use a double suction pump.
2. Slower speed
3. Variable speed drive
All will increase the cost but will operate successfully hydraulically. For
surge protection you will have to get creative (concrete bunker, tank, ?)
Best,
Denny Fegan
Powerdyne Consultants



In a message dated 6/5/2011 11:42:05 A.M. Central Daylight Time,

I still could not understand why a Vertical turbine pump cannot be used? I think that a Vertical Turbine Pump will be ebst suitable for this application due to following reasons:

1. You need a low NPSHR Pump. A Vertical Turbine Pump has submerged impellers hence the NPSHR is lowest.

2. Due to storm surge in the area you can have a platform higher enough to avoid submergence of electric motor of the Vertical Turbine Pump and still have the low NPSHR fulfilled.

Ruhrpumpen produce Barge floating barge pumps. These are essentially vertical turbine pumps (low NPSHR due to pump length) mounted on a floating barge/pontoon. So if there is a storm surge raising the water level the barge merely floats in the deeper water and continues pumping. This seems like an ideal fit for your application.
I really don't think this is suited for anything but a vertical pump. A horizontal pump, even running slowly would have too high an Nss value for an Impeller and would be a marginal Inducer application, but with varying liquid levels I would not recommend this.
A Barge pump is unaffected by storm surge induced water levels.
If this is of interest let me know and I will put you in contact with the Manager of this division. Regards, Ian

what i understand is that - there is limitation to sump depth so unable to increase the pump length so dificult to maintain the NPSH above pump impeller ....in this situation as suggested by Mr. Denny Fegan ..the double suction first stage impeller which will lahe lower NPSHR will be the better solution ....

Amit,
I agree with Denny, for u r requirement having 7500GPM, NPSHR may be around ~4m (considering 0m head at ground level) with double suction impeller for 50HZ, 1500 RPM. try this . this can be even low if you have positive head at ground level.

regards,
Sunil