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Treadle Pump Optimization Project

The treadle is a very simple design that is used to produce rotary or reciprocating motion in a machine, which dates back to Thomas Saint’s original sewing machine design he had patented in 1790 and earlier. This basic component can be used in many simple machines, including grinders and pumps. A treadle pump is defined as a foot operated single acting double cylinder piston pump for low lift irrigation (New Dawn Engineering, 2009). Pumping is activated by stepping up and down on the treadles to drive the attached pistons, creating suction in the cylinder that draws groundwater to the surface (International Development Enterprises, 2010). This water can be sourced from a river or well and is used for irrigating farmers’ fields or to store water in a container for later use. Treadle pumps have been used in many countries worldwide such as Ghana, Zambia (Engineers Without Borders Canada), Swaziland, Kenya (New Dawn Engineering, 2009), Bangladesh, Nepal, India, Cambodia and Myanmar (Cooper Hewitt , 2006), as well as many others. Presently, 84 manufacturers now produce treadle pumps and 1.4 million have been sold to small plot Bangladeshi farmers since 1985 (International Development Enterprises, 2010).

Engineering Principles

How They Work

A treadle pump is a basic cylinder-based pump: it comprises a cylinder fitted with a piston and some means of pushing the piston up and down (Kay, 2000). A pipe connects the water source to the pump, where a non-return valve is fitted to allow water to flow in and prevent it from flowing out. The piston itself must have a snug fit inside the cylinder in order to create a vacuum to draw water in. The piston itself contains a valve such that, when it is forced downward by the treadle, water flows through the piston from the space below to the space above it. The opposite then occurs when the piston is lifted: the valve closes, forcing the water above the piston to the outlet all the while drawing in water from below. An illustrated version of this is shown in Figure 1. In the past, these pumps were hand-operated and quite inefficient, as the effort required to lift small amounts of water was significant. Using the larger muscles in one’s legs and two pistons has greatly increased the efficacy of this machine. A chain or rope passing over a pulley or other device connects the two pistons and associates the upward motion of one piston with the downward motion of the other.

MECH 425 - Treadle pump operating principles.jpg Figure 1: Treadle pump operating principles (Kedge, 2001), adapted from(Kay, 2000)

This pump currently has two monikers, each defined by the outlet portion of the pump. If the water is discharged to an open channel for irrigation, it is termed a suction pump. If the water is discharged to a pipe, it is termed a pressure pump. In the pressure pump, another valve is used at the discharge end, maintaining pressure in the pipe that can be used to drive sprinklers or drippers or deliver water to a header tank (Kay, 2000).

Bibliography

Cooper Hewitt . (2006). Bamboo Treadle Pump. Retrieved April 4, 2010, from Design for the Other 90%: http://other90.cooperhewitt.org/Design/bamboo-treadle-pump

Engineers Without Borders Canada. (n.d.). The Treadle Pump. Retrieved April 4, 2010, from Engineers Without Borders Canada: http://www.ewb.ca/en/whatwedo/overseas/projects/treadle.html

International Development Enterprises. (2010). Treadle Pump. Retrieved April 14, 2010, from International Development Enterprises: http://www.ideorg.org/OurTechnologies/TreadlePump.aspx

Kay, T. B. (2000). Treadle pumps for irrigation in Africa. International Programme for Technology and Research in Irrigation and Drainage. Rome: Food and Agriculture Organization of the United Nations.

New Dawn Engineering. (2009). Treadle Pump for Low Lift Irrigation. Retrieved April 4, 2010, from New Dawn Engineering: http://www.newdawnengineering.com/website/pumps/treadle/





Treadle_pump

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