hydropneumatic tank and booster pump 1

[civileng061960]

The model indicates that the future flowrate is 125 gpm at about 95 psi over the entire small community system. The existing 30 yr old system consists of a well, two above grade 60,000 gal storage tanks, two 5 hp booster pumps and a 20,000 gal bladder tank. The future design calls for an additional storage tank, new booster pumps and a new hydropneumatic tank (delete old pumps and hydrotank). It seems to me that the booster pumps would be sized to bypass the hydropneumatic tank if it is out of service for any reason, but this leads to a 50 Hp pump. Can someone provide some insight on how to size the booster pumps?

 

[bimr]

The head is 219 feet.

Therefore, the

Brake HP = (gpm * head)/(3960 * pump efficiency)

= (125 * 219)/(3960 * 62.5%)

= 11 HP

You can do this project with 2 - 15 HP Booster Pumps and a hydropneumatic tank. As an alternative, you may consider 2 - 15 HP Pumps controlled by VFD's with no hydropneumatic tank.

Not sure where you got the 50 HP?

Bypassing the hydropneumatic tank will not cause the pump discharge to be higher. See the information in the link below:

http://smallwatersystems.ucdavis.edu/Courses/WebCast/default_files/Lecture 6.pdf

 

[civileng061960]

The 50 hp came from a quick input at a pump manufacturer's website. The 11 hp makes much more sense to me. I was concerned about available power. Thank you for the post and the link.