/windmill water pump

[muddstopper]

BIL called me up a little while ago to discuss building a windmill water pump to keep his stock tanks full of water. He had mentioned this project about a year ago and has already built the windmill. He used 8 plastic 55 gal drums cut in half with the halves stacked on top of each other and bolted together for vanes. He put the 8 vanes on a 8ft dia cable reel. Using 1in rod for a vertical shaft. Now he is wanting to build a piston type water pump out of PVC. This is where things start getting iffy. Mostly because the windmill is vertical instead of horizonal and I dont think the 1in shaft material is going to hold up well supporting a 8ft dia x about 6ft tall wind mill. To cap it off the windmill is about 20ft above and 150ft from the pond he wants to pump water out of. Also, he is wanting to run 1/2in pex tubing from the pump to the pond. He has alread aquired the pext tubing. I have looked at several pvc pump designs on utube and think I can pretty much build the pump as they aint that complicated. My question is whether or not the pex tubing will work as the suction side of the pump. My first thoughts are that the pex is made to hold pressure, but I am afraid it will collaspe as a suction line. With 20ft of head, it is going to take about 9 lb of vacuum just to pull the water up to the pump. My second concern is the 1/2in tubing being to small . He's not trying to pump large amounts of water. Not sure what I am getting into, plan on checking things out one day next week. Until then, I need a few opinions and suggestions on how to proceed.

 

[ajmaxham]

What size PVC pump will you be building? Any pump with 150' of 1/2'' pex (.485 ID) suction line and 20' lift will result in very low volume pump. Most pumps are rated at a 10' lift and as lift increase water volume goes down. What will the strokes per min of the pump be? Do you have pictures of the windmill?

 

[franklin2]

Does the windmill run now that part is done?

 

[sidecarist]

The pex should hold up against the vacuum, but it's awful small.

As a rule pumps are better at pushing than pulling the fluid. If it's possible to put the windmill close to the pond and then run the 1/2" pex as the outlet and have a 1-1/2" inlet it will probably work better.

When pulling with a pump loss of prime is always a problem. The close the pump is to the source the better!

 

[muddstopper]

I havent seen the windmill yet as I just learnt yesterday that he had it built. According to BIL, its working and hard to hold by hand, so I assume it has a little torque to it. As for flow, the pump will be used to fill a stock tank with overflow returning to pond. High flows shouldnt be needed. As for the size of the pvc pump. thinking about using 2in sch 80 pvc with 1 1/2 sch 80 pvc as the plunger. Using sch 80 pipe there is only about .040 difference between the inside dia of the 2in pipe and the outside dia of the 1 1/2 in pipe. Video I watched showed the builder cutting groves in the 1 1/2in pipe to accept orings to make the seal between the two pipes. I dont know how long such a setup would last, but it aint like rebuilding or making a spare would break the bank. The one in the video didnt show what kind of pipe was used as the suction or pressure lines, but he used 3/4in pvc check valves and I would guess 3/4 pvc for both connections. I hope we can get this thing to work because I am thinking about building myself one to use in a heating and AC project I have been wanting to build for a long time. Thats a differentt topic I will start another thread for when the time comes.

 

[muddstopper]

The pex should hold up against the vacuum, but it's awful small.

As a rule pumps are better at pushing than pulling the fluid. If it's possible to put the windmill close to the pond and then run the 1/2" pex as the outlet and have a 1-1/2" inlet it will probably work better.

When pulling with a pump loss of prime is always a problem. The close the pump is to the source the better!

Have you seen any specs as to what kind of vacuum the pex tubing can handle, I spent a good portion of last nite searching the web and never found anything to suggest the pex would or wouldnt hold up to vacuum. As for placing the windmill close to the water source, I agree 100%, but also knowing the site, the pond is sort of down in a hole between two hills and not sure it would get the wind it needs to actually work. At any rate, he has already built and installed the windmill so I guess we will just have to try it where it is at and see how it goes. Also, he already has the pex tubing, its blue in color if that means anything, And when I mentioned the possibility of the pex not being able to withstand the vacuum he said no problem, he would just switch it out for pvc. I believe that even if the pex does collaspe from vacuum, it would show that the pump system has the power to pump the water to where he wants it. So it looks like a little trial and error is going to be needed.

 

[radioman]

I understand bil bought the pex already but it can be returned if needed. I understands it's cheap for length you can get since you need close to 200 feet off pipe but i don't think 1/2 inch it's big enough even for low volume. I worked with Pex and I'm pretty sure that it won't collapse since its cold water . I think you may want to upgrade size off pipe since its a low volume flow out will have .51 friction loss per 100 feet. Yours is double that so priming is going to be difficult for you. Just doubling the size of pipe to 1 inch will be under less then half for 200 feet friction loss so friction won't be a problem .

 

[franklin2]

I think I would get a bucket or something and pump out of it near the windmill as a test. A lot of unknowns in this project so that might break it down into manageable problems.

 

[Baby Grand]

Furrball idea #1:

Use the mill to drive a piston/reed valve compressor.
Run air from the compressor, thru the pex, to a 2nd, pneumatically driven water pump, down at the pond, to push the water uphill to his stock tank.

Lossy, to be sure, but avoids collapsing tube trauma, loss of prime paroxysms and the heartbreak of cavitation by maintaining positive pressure in all the plumbing.​

Furrball idea #2:

Put a capstan on the mill and drive a pump at the pond with a capstan on it, using a loop of rope.
Simpler build. 'Course you'd have to keep everyone clear of the rigging so they don't get fouled and go for a Nantucket sleigh ride with an unhappy ending.​

Furrball idea #3:

Move the tower to the pond and raise it enough to catch the wind.

Just tossing them out there to see if the cat licks it up.
Or the dog brings it back.
Running them up the flagpole to see if anyone salutes.

Man, do I love applejack!

-Jim​

 

[Egon]

Some other options would have the windmill generating power with a small electric pump at the pond. Or, go back to early oil patch days where pumps were operated by a cable system from a central power source. That might be an easy way to go.

Jerk line system: