Reversible Pump
Reversible Pump
(OP)
I'm having a horrible time trying to find a pump for my application:
~3 USGPM @ 20' TDH
low maintenance
instantaneously reversibly (no modification required to make it so)
All the lobe manufacturers don't go low enough in flow. I'd like to avoid labour intensive units like peristaltics and rotary vane pumps. There is SAWA out of Switzerland who makes a reversible centrifugal pump, but the cost is outside of my intended price range. Any thoughts?
~3 USGPM @ 20' TDH
low maintenance
instantaneously reversibly (no modification required to make it so)
All the lobe manufacturers don't go low enough in flow. I'd like to avoid labour intensive units like peristaltics and rotary vane pumps. There is SAWA out of Switzerland who makes a reversible centrifugal pump, but the cost is outside of my intended price range. Any thoughts?





RE: Reversible Pump
Reversible centrifugal? If you spin a centrifugal backwards it produces water in the forward direction with marignally less head and significantly less flow. The only way to make a centrifugal reversible is with a network of valves or a reversing valve ...
Hydrae
RE: Reversible Pump
Gear pumps and flexible-vane rotor pumps are reversible too.
RE: Reversible Pump
btrueblood - Lobed aren't, but I can't find one small enough. We don't want to maintenance (or operating costs) of replacing the vanes. Gear pumps may be an option, but there's a concern about the lack of lubricity as we're only pumping water. If by "flexible-vane" you are refering to a flexible impeller, like what ITT Jabsco provides, we have experience with them, however, to reverse them, the impeller needs to be removed and "twisted" in opposite direction. If you're refering to something else, please explain.
Thanks
RE: Reversible Pump
Ok you take the progression of centrifugal to mixed flow to turbine to propellor pump, in each case the head per stage drops and the flow increases, when you get to the propellor pump it is reversible I agree, so to get 3 gpm at 20 tdh it would need have many stages, more moving parts, yes it could be built but at what cost?
Is two pumps and check valves a posibility (one pump for each way)?
Hydrae
RE: Reversible Pump
RE: Reversible Pump
I may ultimately have to revert to that route, but I'm trying to explore my options.
RE: Reversible Pump
Now that I think about it, with two pumps and two check valves as I mentioned above, flow from one pump would just circle back through the other pump- hadn't thought of that.
RE: Reversible Pump
RE: Reversible Pump
You're right about the ITT/Jabsco pump, but there are other versions out there that can reverse just by twisting the shaft. Don't know if they'll meet your head/flow requirements.
If a vane pump will wear out (even with carbon vanes) in your application, then yes, gear pumps are probably ruled out too. But there are a lot of vane pumps and gear pumps used in clear water with pretty long service lives.
A rotary lobe pump would work, but is subject to abrasive wear also (it just doesn't degrade as badly in performance). But, you are right that it's tough to find a manufacturer, much less a model in the "right" size. A gear pump with loose tolerances on the pump gears, and external timing gears (like a lobed rotor pump) would work as well, and maybe you could fabricate one to suit your needs.
Check www.fristam.com - they have a rotary p.d. piston pump that is advertised as reversible.
RE: Reversible Pump
http://www.boergerusa.com
They have a rotary lobe pump, with helical lobes (reduces pulsation), and with hard metal or soft elastomer impellers. These last would work great in a condition with potential for solids ingestion (tends to cause major malfunctions in hard-metal rotors). Their 25 frame size pump peaks at about 12 gpm, so it would work well in your application (just run the pump at lower rpm).
Another possibility is
h
They have a 45 frame size pump that goes up to 69 gpm, a little big...