Coil Pump V2.0 - testing rig

This Instructable is a guide to constructing and operating a simple coil pump.

Sousdey from Cambodia, and welcome to our project!

Following our first Instructable, How to make a very simple hand-operated water pump using components easily found around most properties, we have developed our project to address some of the problems and inefficiencies and we encountered with our first coil pump.

Here are our included improvements for this pump:

1. Include a central axle and bearing to more easily control rotation and rotational speeds
2. Include a swivel joint that allows the pump to rotate while the outlet pipe remains stationary
3. Increase the diameter of the hosepipe used in the pump
4. Increase the length of the hosepipe used in the pump
5. Use a single length of hose for the whole pump assembly
6. Increase the overall diameter and length of the pump to approximately twice their original size
7. Provide a jacket for the pump to protect the hosepipe during operation

The following steps of this Instructable detail how to make and operate our coil pump V2.0, which outperformed our V1.0 pump by 10x - we moved 21.7 liters of water through 3.1 meters of vertical height in 3 minutes... and there's still room for improvement.

Thanks for visiting - we hope you enjoy this build :D

Aziza's Place, Cambodia.
http://www.azizafoundation.org/projects_aziza.html
http://www.facebook.com/pages/Azizas-Place/339342099551
http://www.instructables.com/id/Coil-Pump/

*Edit - Monday 05 September 2011 - The comments section of this Instructable has been handed over to students studying English at Aziza's Place. If you have any questions for the students, please ask them here... we'll get right back to you. (Moderated)

*Edit 2 - Wednesday the 14th of September 2011
The students are currently working on designing a source of motive power for this pump - see step 9.

*Edit 3 - Friday the 30th of September
We've now designed a power source for the pump - a garden swing - see here for 3 videos

For this project, you will need:

Build time
1 full day

Tools
a gas blowtorch or similar heat source
an old 8mm bolt
a sharp knife or strong scissors
a thin, flat spanner
a regular spanner
a metal bar or tube with a slightly larger outside diameter than your hosepipe

Materials
a large bucket
a bicycle wheel
an empty 20 liter water bottle with a screw-on cap (a bottle from a drinking fountain is perfect)
X meters of hosepipe
pvc plumbing fittings
brass plumbing fittings
jubilee clips
a roll of 2" wide scotch tape
an old flip-flop
several large-diameter metal washers
one of the nuts that originally held the wheel onto the bicycle
a tub of automotive grease
a contained source of water for the pump

Step 1 Axle and bearing

In the centre of the front wheel of a bicycle is a small axle; this axle forms both the support and main bearing of our V2.0 test pump.

1. Remove the front wheel of a bicycle.
2. Loosen the 4 nuts that hold the axle and bearings in place and slowly thread the axle through all of the nuts until the axle protrudes as far as possible from one side of the wheel and you can still tighten the nuts to it on the other side of the wheel.
3. Re-tighten all of the nuts and lock the axle in its new position.

Before beginning this step, it would be a good idea to check whether you have chosen a good wheel to use.
Flip the bike over to stand on its saddle and spin the front wheel.
Check 2 things:
1. The wheel is straight - look for side-to-side movement of the wheel rim as it rotates
If you know how to straighten a bike wheel, get to it. If you don't know how, here's a link to truing a wheel. Unless it's a really badly bent wheel, it won't affect your pump.
2. The axle is straight - assuming the wheel is straight, remove the nuts holding the wheel in place and then spin the wheel gently while it's still on the bike; look for movement in the ends of the axle.
A bent bike axle cannot easily be fixed, but unless it's really badly bent it won't harm your coil pump - find another axle or another wheel if you want to.

Possible problems:

• The axle nuts have become frozen with age. Find some penetrating oil or WD40, spray the problem areas and leave the wheel overnight for the lubricant to take effect.
• Loosening the nuts around the wheel axle bearings too much may mean that the ball bearings fall out. Be careful and be aware of this when adjusting the axle position, don't move the nuts far from the wheel - just loosening them enough to be able to turn the axle through them is OK.
• The bike wheel won't spin freely now that I've adjusted the axle. The nuts are too tightly closed into the wheel. Loosen the nuts on one side of the wheel until the wheel spins freely and then lock them in that new position - it may only be a tiny adjustment... see here for more details
• The axle wobbles in my hand and the wheel doesn't run in a level circle. The nuts are too loosely closed into the wheel. Bring the nuts on one side closer to the wheel until it runs smoothly and then lock them in that new position - it may only be a tiny adjustment... see here for more details

The bicycle is without doubt the best form of transport in the universe, and a healthy bike should most definitely be kept in one piece and used for its intended purpose as much as humanly possible.
We can assure you that no bikes were permanently harmed in the construction of this pump.

(If you're wondering what you can do with the bike that has no front wheel at the moment, take a look at this...)

*Edit - Monday 05 September 2011 - The comments section of this Instructable has been handed over to students studying English at Aziza's Place. If you have any questions for the students, please ask them here... we'll get right back to you. (Moderated)

Comments

[VagsmaCutter]

Outstanding!!!

[jaypublic]

Is this pump to be used for pumping drinking water?
If so, using automobile grease for a seal is not good.
Many cancer causing things in it.
Much better to use silicon grease, if you can get it.

Though now that I think of it, having clean water contaminated by a little axle grease is still probably safer than unclean water.

Best to you, and thanks for the instructable.

[Azizas Place, Cambodia]

We're only using grease until we can come up with a viable alternative. It functioned better than anything else on test day, but it would be no good for a pump installed for a much longer testing period than we had, or for an installation in which the swivel joint's not accessible during testing.

[greenspider]

I wonder if you have tried an air hose swivel joint (used on air tools to keep the hose from restricting movement)?

[Azizas Place, Cambodia]

Evening, greenspider.
Never even though of that!
This looks ideal, but 1/4" is way too narrow... is it possible to get them in larger sizes?
http://www.airlines-pneumatics.co.uk/webcat/Detprod.asp?ProductCode=S010145

[greenspider]

http://www.ebay.com/itm/1-2-Pneumatic-Air-Hose-Swivel-Fitting-JET-3-Pcs-JAS12-/400235013363

This is 1/2".
Will it work?

[Azizas Place, Cambodia]

Looked at your links and that or similar looks to be what we need, but in a size that won't restrict flow.

We need to find that part here in Cambodia, really - or have one fabricated here.

I'll take a photo down to the market and see if they're available locally.
Thanks!

[greenspider]

http://www.ingersollrandproducts.com/accessories/catalog_pdfs/Supply_Fittings_Hoses.pdf


Ingersoll/Rand.
They have straight swivels if needed (up to 1/2")

[kleinjahr]

Interesting version of an Archimedes screw. If you put a paddles on the bicycle wheel , you can place it in a stream/river for pumping irrigation water.

[Azizas Place, Cambodia]

A design like that was the idea behind this project, kleinjahr.

Our requirements differ in that the pump needs to be used with still water.

[yeti bear]

i would sugest a heavy flywheel. this would keep rpm more constant and allow the person doing the work to take quick breaks.

[Azizas Place, Cambodia]

I'd agree there, yeti bear.
Quite a lot of consideration went into making this pump design be as near to neutral buoyancy as possible, but a reasonably heavy flywheel on the powering mechanism out of the water is being considered... depending on the way the pump responds to the powered input; it's a little too complex to model and will need to be a trial and error discovery.

[beingthere]

Hi all, Would a cone shaped coil in the centre of the bucket work better than the straight sides of the water container? my thoughts are that a cone shaped coil would continue to excelerate the water all the way to the outlet.

[Azizas Place, Cambodia]

The quick answer is Yes!

The outlet coil of our pump being 78% the size of the inlet coil is pretty much an optimal size for the configuration we have - any modification would be to increase the diameter of the bottle as the walls rise to the neck, with the largest coil on the bottle not quite matching the smallest coil on the bucket, thus smoothly continuing the taper from the bucket to the pump outlet at the base of the bottle.

I'm not sure about the water being accelerated, though.
The pump's power comes from the air trapped in the successively smaller coils becoming compressed.
As each pipe coil shrinks, so does its "inhabitable" volume. Water can't be compressed, (at least not measurably by this device), so the air volume shrinks with each rotation. This compressed air is released into the outlet pipe and expands, pushing the water along the pipe.... at least - that's the idea ;).

[germeten]

It's nice but I have a question. Why not just wind the tube inside the bicycle rim spokes and turn the wheel in a shallow tray of water. The inlet end of the hose would be close to or touching the tire/rim and the outlet closest to the axle. If you use an eccentric to turn the wheel you could power it by a Milkovic pendulum (see Ray Head's videos on youtube.) There are other coil pumps you can find there.

[Azizas Place, Cambodia]

Afternoon, germeten.
Tried and failed, I'm afraid.



I was trying to construct a pump that would still allow the bicycle to be used, but ran into problems with the pump's outlet - it needs to be central to the wheel's rotation, but to allow that, I would have needed to perform major surgery around the forks and axle... not really feasible for purpose, here.

Another problem was that the distances between the spokes changed toward the outer edge of the wheel and didn't allow for the hose to pass through easily.

Perhaps it's possible - but I considered the amount of modification and fabrication disproportionate when seen in relation to the power output and amount of water that the pump would actually move with the limited pipe it contained. Smaller pipe may well work, but that would severely restrict the volume of output.

[germeten]

Instead of the bicycle wheel you might use two large disks with the hose coil
sandwiched between. The axle on one side would need to be hollow and serve as the outlet.

[Azizas Place, Cambodia]

That's correct, and that would be a spiral pump. They need a lot of support to hold the coil in place, and that wasn't for us with this build. A pump contained in a bicycle wheel would have either the capacity for lift or volume, but not both.
For lift, you need more coils in the pump, while for volume, you need a larger pipe diameter - you can't get both in a bicycle wheel, unfortunately.

Our pump here is a hybrid spiral/coil pump, and doesn't need much in the way of external support at all. It can easily be scaled up in size to suit both lift and volume.

[pbates123]

Hello Again, Just thought a stationary bike drive system may improve the RPM/Flow Rate. But I like the Swing Idea sounds like more fun!

Also just a question. Several of these pumps shown online simply sandwich a coil of tubing between two disks. While your wrapping around the bottle then placing it in a bucket. Seems more complex to me. Is there some space concerns or other reason for this design?

Your getting some respectable numbers there!

Regards,
- Phil

[Azizas Place, Cambodia]

Evening, Phil.

We chose a swing as one of the students asked if it could be powered by hammock - so I expanded on the idea. We'll be having English classes based around discussion, drafting design, and model-making from Monday and I hope to get a swing built and operating within 2 weeks.

Re the pump design... The large, flat coils are not stable without a lot of support, and building that's not an option for us.
We needed to fit a large number of coils into a small space that in itself had near-neutral buoyancy and didn't need lateral support.
Approaching the idea of an ever-decreasing (to 75% of starting diameter) spiral coil led to a long and seemingly fragile shape. Then the idea occurred that the spiral could be split at its midway point and reversed up its own center - that in turn gave the basic tapered barrel shape.
Next, as per project guidelines, was to find a suitable object laying around to build with... a large plastic dustbin with the correct taper and internal dimensions to match the water bottle was a lucky find. We really should refine our taper to include the bottle, but we're trying to keep things simple re construction and have gotten decent results with it as it is.

[menahunie]

I am curious about this whole post?
Is this just an exercise in a science project involving pumping water?
Allot of materials are used that many don't have in Cambodia in the first place.
If this project is for everyday use it isn't really efficient.
You can move way more water and allot faster using a simple 5 gallon bucket on a rope and hauling it up to the first floor from the ground.
One lift of a 5 gallon bucket is 18.9 liters in a number of seconds instead of minutes as your pump takes.
Your 3.1 meters is about ten feet high.
Your moving 7 liters per minute.
So say I take ten seconds to haul one five gallon bucket up ten feet - that is allot of time. So I do this 6 times in your one minute.
That is 30 gallons of water or 113.4 liters per minute for your test time of three minutes total 340.2 in this time.
Besides a rope and a bucket is way more reliable in the long run..

[Azizas Place, Cambodia]

Hello, menahunie - thanks for your comments and curiosity.

English classes at Aziza's Place are project based.
The students generally choose their own topic to study and their own project to complete, which both allow for the introduction, use, and assessment of use of language structures entirely in context. There are classes of differing levels of language ability, and the kids have studied many different topics and produced many different "projects".
Those projects have varied widely in form and have included such things as making a tourist information poster, adapting Aesop's fables for a short school play, writing short books, making masks, a trip to a restaurant, etc.
This particular project was begun as a Saturday morning practical activity of the teacher's (my) choice. It proved successful and reasonably popular, and has since been incorporated into English classes as a topic for the older students.
For example, we studied the first conditional based around design changes and improvements, and shortly we will study future forms in the modeling of the swing that will power the pump.

All of the parts and materials for this pump are from Cambodia, and, with the exception of the hosepipe in the V2.0 pump, all of the parts were re-purposed after being gathered together - they were generally laying around or in other uses before we started. We have bought the rainwater pot, some new hose, and a few plumbing parts (from the market here) at a total cost of around $30, of which $20 was for the made-to-measure rainwater pot.
The guiding idea of this build is that the pump can be built very cheaply from parts readily available in most places in Cambodia and can be constructed without the need for any special skills.

I agree with your comments about hauling water upstairs with a bucket and rope, but...
What if the water isn't downstairs, and is a few hundred meters or more away from the house?
What if you're elderly or incapacitated and can't lift 18.9 kilos (one 5 gallon bucket) ?
What if you have a vegetable garden to water and need to carry many buckets repeatedly in a dry season in which the temperatures can exceed 40'c and humidity can exceed 80%?

The coil pump can not only lift water, it can push it long distances, too... and with far less effort than the backbreaking toil of carrying 20kg weights around.

The pump we have built is only our second attempt at this, and this principle and design can easily be enlarged and improved upon, as we have shown already. When this system is scaled up, and is operational "in the field", I think that its benefits over manually transporting water will immediately be obvious.

Reliability... what is there to break? Possibly the bicycle wheel's attachment to the bucket, but that's only there for testing purposes - to make the pump tightly controllable inside the rainwater pot - it won't be needed as a part of the pump in the final design.

[pbates123]

I am impressed! I though there had to be some constraints that wasn't clear to me. You seem to have done really good with the design and implementation - my hat's off to You!

- Phil

[dreadengineer]

In case anyone wants a picture of the principle of operation of a coil pump, a good one is here, most of the way down the page:

http://www.fao.org/docrep/010/ah810e/AH810E06.htm

[Azizas Place, Cambodia]

That's a good information source, thanks!

It shows a coil pump and a spiral pump - but what we did here was to combine the principles of the two... we have made a "coiled spiral" pump.

[tater1]

http://lurkertech.com/water/pump/tailer/

For More Info Ck Out this site

[iamunique127]

A truly inspiring Instructable.
Teachers are a special breed and you are obviously one of the outstanding ones.
Those kids are so lucky to have you as a role model and educator.
I hold you in the highest regard.
Thank you.

[billbillt]

This is pure genius... Efforts such as yours to help the people are always held in supreme regard by me...Work such as this will make the earth a much better place for all...

[cavalaxis]

This is the best 'able I have ever read. The troubleshooting alone is brilliant. Thank you for such a wonderful read.

[Azizas Place, Cambodia]

:D Thanks.

[Corrugator Supercilii]

Archimedes himself would be proud, very nice project, great work!

[AlphaRomeo]

I had a quick glace at the project and shall study in detail later. But what I have seen is

Truly an work of excellence - and what I liked most about the project is the quantitative results - the numbers which tell the real story.

May be you should also think of charging batteries by attaching a dynamo - then exercise machine, a pump and a power generator rolled in one.

[Azizas Place, Cambodia]

Thanks very much, AlphaRomeo - coming from a science educator that's praise indeed!

One of the students has requested that we try to make it hammock-powered, well, we'll see. Perhaps driven by a garden swing would be close enough for him.
We need to match up some gear ratios, figure out some pendulum formulas and we've a rain-barrel full of other Math to do...
Now, where did I put my calculator?

[batman96]

I could carry that bucket up those stairs in 1 minute.

[Azizas Place, Cambodia]

Hahaha, yes - but a coil pump can send water hundreds of meters horizontally as well as vertically; rumour has it that they can even push water up to a mile before lifting it. This is our second design and trial, we've spent diddly on parts and materials, and we haven't finished scaling up yet.
When we start to approach the limits of the capability of this pump I'm pretty sure you won't want to be carrying that particular bucket...

Thanks for the Monday morning chuckle :)