Question about lifting water through a water pipe.

[ConnorJohn]

Hello!
First post, hope you all can help me out. I’m a peace corps volunteer in Nepal and am trying to implement drip irrigation for my school garden, since this season, we get water for about 30 minutes in the morning through a tap that is “always open.” The water that comes has some pressure, or else I’d have given up a while back since the water must be lifted to the top of the plastic.. (jeeze, I forgot the name in English...)... to the top of the plastic... TANK. There it is. Batta in Nepali. (May be forgetting English but at least I am using metric...)
However- to my dismay, the required lift is too high for the water pressure(flow? What is correct to say there?) coming from the tap this time of year.

1. Here is my thought- Bernoulli’sprinciple states that in a horizontal pipe, as water velocity increases, pressure decreases. (Right? I want study to be an ecological engineer after service- better have that right!)
But what about in a vertical pipe? I mean, if when the pipe is vertical in my system, I switch it out with a smaller pipe(using the oddest looking connector pieces available in my bazaar), would the water be able to be lifted higher?The velocity wouldn’t increase but the diameter of the pipe would decrease.. At the expense of the flow, I assumed it would- and don’t mind the loss of water per time unit- to a degree. Is this worth a try? Or should I revert to lowering the tank in spite of wanting as much PE as possible for the drip irrigation system.

I’ve decided to take this garden andwithin it talk about the science of gardening and ag tools like dripirrigation and plastic tunnels. These kids are so darn smart! Easily understanding potential energy(why should we raise the tank?), etc. I actually sent some of their questions to the ISS to beanswered by a returned PCV who is working up there. It was a fun project.. received a video of two astronauts from Peace Corps! Anyway, if you could help me out here- I would greatly appreciate it. Plus you’d be apart of my service..that’s kind of special! If I can manage to get this photo uploaded, you might be able to see why I’m looking for DI. Ironically, this project took a few months extra time to get the materials, afterabout a month it will be monsoon season- and we will be burdened with too much water in Nepal. HA. Life is beautiful.

2. If a pipe’s height first decreases 3m, then rises 4m- would the output be the same as it just increasing 1m through a pipe of the same size? If at the lowest point I use a smaller pipe as I rises- how light that affect the output? Flow and velocity would certainly be restricted, does that mean pressure would increase?

Thank you so much and I hope to hear some ideas ASAP!
ConnorJohn

 

[Tom.G]

Sorry, a smaller pipe or a horizontal one will not help. It is probably best to lower the tank.

I can think of one way two ways to lift part of the water.

• Use the flow from the tap to drive a water wheel, with the exit flow from the water wheel to a tank at the same level as the tap. The water wheel could drive a pump or a bucket elevator (see the next post) to fill the higher tank.
• There are some pumps made that use air pressure on a diaphragm to drive a diaphragm pump, that could maybe work. But by the time you find the right one you may have left the Peace Corp!

You can not raise all of the water with either approach, there will still be some left in the lower tank. That is because there is not enough energy coming out of the tap to lift all of it. If there was enough energy, you could just pipe it to the higher tank. These approaches use more water to get enough total energy to raise some of the water higher.

Interesting project. Please keep posting here to tell us what is happening.

p.s.

the required lift is too high for the water pressure(flow? What is correct to say there?)

Yes, pressure is right.
Cheers,
Tom

 

[Tom.G]

 

[256bits]

How much water are we talking about - certainly not an Olympic sized swimming pool amount.
Sometimes a simple solution, such as filling a bucket and pouring it into the tank works fine.
Using a little muscle power over an overly complicated setup gives a bit of being involved in the project for the participants.

 

[ConnorJohn]

Thanks for all your answers!

I was just curious about finding a solution using the materials I had- like the pipe and a smaller pipe. I appreciate the pump ideas a lot and it would be great for the kids to learn to engineer something like that! As it’s an educational garden with a focus on nutrition and science, after all.

That being said, pumps wouldn’t be realistic in this situation, I don’t think. As for using muscle- using a pipe was one answer to a cultural issue I wasn’t expecting to face.

There is a woman who cares(cleans, etc.) for the school alone- she is of a lower caste, and when I try to get the kids to do anything requiring labor the principle just makes her do it- behind my back- trust me I’ve tried!

The kids are really excited about the garden and If I couldn’t use a smaller pipe, I was going to give them a short speech about “our garden.” It’ll probably work, but since I had the materials, I thought I’d ask. It’ll be a fine way to teach about teamwork(fire line), as it is quite a distance away from the tap. Also, buckets are really expensive and we don’t have any at the school. I’ll probably start a garden fund with the kids.

See, pipe was a bit simpler but writing out realizing there are many more benefits carrying it instead.

Thanks for all the replies,
leading to realizations,

Cheers!