The earliest float valve flow controller was housed in a PVC tube segment with PVC caps on each end (Summer 2007). This design was abandoned in favor of using a manufactured plastic bottle. The manufactured bottle allows uniformity across all flow controllers we assemble and use, and it also increases the ease of producing the flow controllers.
At the beginning of Fall 2007, the flow controller was slightly redesigned and a polystyrene jar was used instead of the previous bottle design. This container is more appropriate because it is clear, allowing us to see what is happening inside the flow controller. It also has a wide mouth which makes it easier for the float valve to be assembled and maintained. In addition, the container is wider which will allow a full range of float valve positioning to take place. Originally, these containers would crack when the inlet and outlet holes were drilled. A variable bit for drilling was used instead, which solved this problem. The material was still brittle, though, so other clear, wide-mouth jars of various materials were experimented with throughout the course of the semester.