Non-clog sewage low flow high head pump 1

[CrazyHorse81]

I need some help finding a pump (or other method of conveyance) that can pump sewage at approximately 170 gpm and 314' TDH, efficiently. We have thought of two pumps in series and two lift stations, but that seems that it would be an operator's nightmare. The operating point is peak wet weather flow at 4 feet per second over 9,500' for a dynamic head of 154' and an elevation head of 160'.

 

[SteveWag]

I usually do that kind of flow/head using two pumps in series in one pump station. If at all possible I use one submersible and one vertical dry pit, with the dry pit mounted directly above a submersible. I use mechanical seals in the dry pit pump. I generally try to find matching pump curves and split the head more or less evenly, although this is not required. I start the submersible first (20-30 seconds) and place an air release valve between the discharge of the dry-pit pump and its’ check valve. I treat the two pumps as one, that is no cross connection piping. I try to avoid 3600 RPM motors and pumps but this is a personal thing. You may look at Gorman-Rupp, they have a two pump in one assembly, with a centrifugal pump mounted above a suction lift pump and driven by one motor. And just to show my age, you may try an ejector station, although the flow is a little high. Whatever you do, pay attention to the check valves and the potential for surges and hammer in the discharge.
Steve

 

[stanier]

Alternative may be a slow running progressive cavity pump such as Mono. You may need a Muncher upstrewam to protect the pump.

 

[Artisi]

The main problem is selecting a pump capable of the high head at this flow and able to pass raw sewage - a pump for this flow and head means a fairly large diameter narrow impeller and being a narrow impeller it won't have the solids handling capability for raw sewage - unless it is macerated on its way to the lift station and even then the flow / head could still be a problem then running at a speed to give reasonable service life - 1450 rpm /50hz or 1750 rpm/ 60hz.

Seems stanier's suggestion could be a good way to go.

 

[Compositepro]

http://www.wastecorp.com/plungerpumps/Wastecorp_plunger_pumps.pdf

 

[curtis26]

I too would look at the reciprocating plunger pumps. They are good for high pressure low flow applications and have been used on sewer cleaning trucks for decades . Giant Pumps and Gaso both have pump models specificly designed for sewer this application.

 

[stanier]

Sydney Water in Australia has many installation of progressive pumps on such service. Yes there is a macerator (muncher) upstream.

This type of installation is far less costly than a reciporcating pump. These types of pumps would require a macerator as the clearances through the valves is not large enough for your process. They are also high maintenance items in such service. Pumping sewage is an intermittent duty normally. Settling of solids in such valve chambers causes problems.