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.