Electric powered systems
In contrast to water-driven pumping systems, there are electrically powered pumps that are used to inject sani tizers into water systems. We’ll be discussing two of the most common types below, diaphragm pumps and peristaltic pumps. These metering pumps both require electricity to run, typically 120V and come in a variety of sizes for agricultural applications. Regardless of the system used, they will both require a reservoir of sanitizer to be located near the pump, in order to draw the solution up and inject it into the water system. Frequently the hoses going into the sanitizer reservoir will have a weight to keep the inlet of the hose below the surface of the sanitizer and a filter to keep the hose from becoming clogged with debris. A check valve must be located just prior to the injection point. This helps to prevent back siphoning of the sanitizer into the water source in the event that water flow stops unexpectedly. Diaphragm pumps are motor-driven pumps that work using a flexible membrane. This membrane moves back and forth driven by a piston. As the diaphragm is pulled back a valve on the water system sidecloses, the valve on the sanitizer side opens and the sanitizer is drawn into the pumping chamber. When the diaphragm is pushed forward the valve on the sanitizer side closes and the valve on the water system side opens, and the sanitizer is pushed into the water system.
The injection rate of sanitizer into the water system is controllable by adjusting the speed of the pump. These diaphragm pumps come in various sizes and are available with variable or fixed speed motors.
Figure 9 - Diaphragm pump diagram with the internal diaphragm extended and compressed, pushing and pulling chemicals into the water flow. (Faith Critzer, University of Washington).
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