...
The original CDC was designed to have a linear relationship between the flow , of alum and the height of water in the entrance tank. The CDC itself is a combination of three previous subteams: the Linear Flow Orifice Meter; the Chemical Doser; and the Flow Controller. These three devices work together to automatically change the amount of alum that enters rapid mix as the flow through the plant is increased. A description of these devices, and how they work can be found below. Since the CDC is currently in use in Honduras, the goal now is for this Spring was to make a the design more robust design.
Current Research
The vertical drop portion of the CDC was tested with various tubing diameters to determine the failure point. If free fall or open channel flow was observed within the vertical drop tubing, then the dosing would be accurate. We determined that the smallest allowable inner tubing diameter is one quarter inch.
...