MakeShift 04: Mark Trageser’s Most Creative Winning Entry
by William Lidwell
March 16, 2006
Mark’s KISS approach and excellent illustrations earned him the respect of DEKA engineers and the MakeShift Master – Creative award. The DEKA team comments: “Mr. Trageser proposes using the plastic to create a pump and delivery pipe that works similar to a peristaltic pump, or perhaps more like squeezing a tube of toothpaste. This is an approach that is simple, straightforward, and unique among pumping schemes. There are several significant issues with this approach: the seams in the bag and tubes could see thousands of pounds of load, and the plastic itself may not be able to take the hoop stress created by the few psi of water pressure over such a large area. However, Mr. Trageser identifies both of these issues and has clearly thought through the problem. It is also nicely described and illustrated.” Congratulations, Mark!
To solve the MakeShift solution for water fields in a drought I took a simple approach. I am calling my design a pull tube pump.
Using plastic sheeting, roll several long plastic tubes to create a hose. Approximate diameter 6 to 10 inches. Rolling multiple layers of plastic several times makes it durable and helps seal the edge.
Securing the edge is the trick. Fold the tube at one side, catching the inner and outer edge of the sheet. Secure this edge to seal the tube. One of several methods can be used depending on what specific materials are around. The edge could be sewn with heavy cord. Glue or tape might work but are unlikely to be available. Other methods may be substituted as long as the seam is strong and reasonably watertight. Attached image files show piercing the sheets at numerous points with wire. Use some sort of washer made from recycled plastic trash to prevent the plastic from tearing.
Using a similar attachment technique, join several tubes end-to-end to create a hose long enough to get from the water source to the crops. Or to a cart made from farm equipment, tractor tires, and the large container.
Create another tube with a diameter significantly greater than the first tubes, perhaps 30 to 80 inches. The size of this tube will be the amount of water you can move per pull. Very big will be very heavy. Small means many repetitions. A short fat bag will require stronger pulling force and seams. I suggest 3 times larger than the hose and 10 feet long. A medium-sized tube equals medium weight to pull. Long tube means fewer repetitions.
Fold corners of one end of the tube in several times and affix in manner used earlier. Create a funnel from the larger diameter bag to the smaller of the hoses.
Attach funnel bag to hose.
With mouth of the large bag open, walk into water allowing bag to fully fill. Small weights at outer edge may be necessary. Once full, attach ropes at either side of the open tube opening. Tie the other end of the ropes to a donkey or two.
Walk the donkey away from the water. As the ropes pull [with a little guidance] they will fold the plastic bag over near the opening, causing a pinch point. As the pulling continues the weight of the now trapped water will push on the fold, closing it tighter. [One could also seal the open end… but that would be time consuming.]
The pulling force of the donkey will roll the far end over the tube. This will compress the water and force it further down the tube. This force will continue and increase as the donkeys continue. Water will be forced up and over the edge of the pond and down to the thirsty plants via the water tube. A slow steady pull would be best for the system to not overstress it, and also agreeable to the donkey’s sensibilities.
Repeat the process 7-9 times for more water. Make more bags and get all the donkeys to work for even more water. Several medium sized systems seem like the best choice, rather than one huge, overly strong device.
I believe that this very simple pull pump could be easily constructed, used, and maintained. Especially if you can get past the issue of sealing the edges of the plastic, and the plastic is durable enough to hold the weight of the water. I guess it should work. I am unsure, as I just made this up and don’t have any donkeys or a pond to test with. It works with a plastic newspaper bag and a cat water dish in my kitchen.