Water driven power unit with dual shafts?

You wont be able to use a gear pump for this application it just wont work. a Pelton wheel is the best device or alternatively a centrifugal pump. The Pelton turbine would be easier to regulate. The only problem I see is the peristaltic pump will need to run a low revs whilst a fan needs high revs.

coconutpete - The Pelton wheel would indeed be able to provide the dual shaft requirement. I also am wondering about a (sliding?) vane pump for the application. To account for the varying speed/torque needs I plan on using a small guage sprocket and chain for the peristaltic pump. Why would you toss out the gear pump??? I am mostly woried about corosion/lack of lubrication (if using a unit designed for hydraulic oil) since the fluid is water with disolved mineral fertilizers.

WyoPatriot

I dont think you would get enough drive from the liquid hitting such a small area as it would in a gear pump. I think it would disperse and simply either pass through the pump or pond at the inlet and the force would be lost. The sliding vane idea might work though. Shouldnt have a problem with corosion with sliding vanes as long as the body is stainless

coconutpete - I am sure you are right about the gear pump now that I think about it... I'll look more closely at the possibilities for the turbine and the sliding vane. Thanks.

WyoPatriot

Some Evaporative air-con's use this principle, where the fan that drives the air through the cooler also has the recirculation pump on the same shaft, so 1 motor do run the whole apparatus.

Hello WyoPatriot - using your max flow 10 gpm, power in the water is about 87 watt. On such a small unit I doubt whether you'd get more than half that as shaft power from your machine (gear pump, turbine or whatever). Is that enough to drive the fan and peristaltic pump?

(BTW, I used to have a colleague who called them paraplegic pumps )

Codey

Why not leave your motors in place and install a generator at the water supply with a simple waterwheel or turbine type blade driving a belt .

A basic motor ( a driven motor becomes a generator) can be utilized in place of a generator head to create power simple and easy to put together .

I'm with you Codey. There ain't much power there, and conversion efficiency would have to be pretty good to run a fan. Peristaltic pump -- maybe. Depends on how much work the pump is required to do.

You might want to consider a Banki turbine. I've seen home grown versions welded from steel pipe. Wiki - Banki turbine.

All - Thanks for you input on this topic. You are correct in stating that there is not much power available from the water stream as described. I measured the amp load on the fan and the pump individually and get 400+ watts. I'll need to look at another way of going about this.

WyoPatriot