Wednesday, June 6, 2007

Second Treadle Pump, Three Inch Pistons.





In the last post I promised another treadle pump with three inch pistons. Here it is. If you compare it with the first version, you'll see the cylinders are larger in diameter, shorter, and installed at a different location in the treadle frame. The treadles and treadle stops are lower too. The purpose for locating the pumps where you see them was to provide greater mechanical advantage to the operator. The pump works great. The larger piston diameters required the mechanical advantage we built in this time as expected. This time I talked my wife into acting as one of our test subjects. One of our concerns is that people shorter and lighter than Jim and I must be able to operate the pump. My wife fits the small size requirements, and she had no problem moving water to a height of 25+ feet.

The second photo shows one of the three inch pistons. The commercially manufactured check valves can be plainly seen. The pumps are mounted to the treadle bases with short sections of all thread rod secured under the bases with "t" nuts and passed thorough plywood donuts made to closely fit the outside diameter of the cylinders. Nuts and washers tighten down the donuts against the pump bases and hold everything secure and upright.

Last time we were too busy and disorganized to make videos. This time, due to popular demand, we have videos to post, which I will do as soon as I can get them uploaded.


6 comments:

baguette said...

I like the way you have seperated the two pistons. Most designs for treadle pumps seem to clamp the two pistons onto a separate chamber at the base of the pistons. Yours seems simpler and would be easier to fix I imagine.

Anyway do you have any details on what you used to make the
piston seals and who makes the commercial valves you are using?


Martin

Smitty said...

The check valves are maunufactiured by The Specialty Manufacturing Co. Their website is http://www.specialtymfg.com/plastic_check_valves/687_check_valve/default.asp We haven't settled on what valve we'll use, but as you can see from the video, these work fine.

Smitty said...

The seals are made of leather. Scroll to the bottom of the blog, and you will see a link to older posts. Click there, and you'll see posts on how the seals were made and how they work.

kelvin said...

I really like the approach in which u have shown the mechanical advantage of pumps and the way you have normalized the features, really nice concept.

Anonymous said...

I live near Seattle, Washington and would like to purchase a commercially made treadle pump. Do you happen to know of a U.S. or Canadian company that sells them? thanks! -Niel

Smitty said...

Neil, No, I don't know of any U.S. or Canadian manufacturer of treadle pumps. That is one of the reasons we were motivated to design a pump that anyone with reasonable manual skills, access to ordinary hardware store stuff, and a few tools could build themselves.
Maybe we should have started manufacturing pumps?