Automated Flow Control Scientific Paper Rough Draft
I will finish the paper by tuesday I just have to study for an exam. Hopefully that is acceptable. I thought it would go faster but it's hard to get the formatting right.
Title: Linearize the Correlation between Head and Flow Rate for Use in Water Purification Plants tentative
Abstract
Initial concepts for a non-electrical technique for the regulation of alum addition in a water treatment plant were tested. A riser pipe was fabricated with holes to mimic a sutro weir was added to the entrance tank of a water treatment plant. The entrance tank and riser pipe were evaluated on their ability to provide a linear correlation between water height in the entrance tank and the flow rate through the plant. Flow rates between 5 GPM and 36 GPM were tested in a pilot water treatment plant. The flow rate was shown to be linearly related to water height with the riser pipe implementation with a percent deviation of ten percent. This will allow creation of an alum flow control module regulated by a float system in the entrance tank. The experiment shows a significant achievement in the movement to bring clean water to communities without access to electricity.
Introduction
Adaptation of water purification technology for use in developing countries is a concern of growing urgency. The lack of clean drinking water provides an avenues for infection by waterborne pathogens which is currently one of the major causes of mortality for children under five years old. One example of the adaption is the regulation of alum flow into the flocculation based system as flow changeswithout the use of electricity relient devices. The design uses an entrance tank as a way to transfer information about the flow rate to the aluminum sulfate flow control module through a float system. In order for the system to accurately deliver consistent aluminum sulfate dosing into the inflow the height of the water in the entrance tank must correlate linearly to the flow rate through the plant. Without intervention the flow rate through the entrance tank is proportional to the square root of the pressure head, height of the water in the entrance tank as shown in equation 1.
Equation 1: The orifice equation
The sutro weir developed by Victor Sutro in 1915 can be used to create a linear correlation between head and flow rate. The configuration is shown below in figure 1.
Figure 1: The Sutro Weir
The bottom length of the sutro wier is reltively large and gradually decreases as the height increases. As the height of the water in the tank increases the pressure created by the weight of the fluid causes the flow rate through the bottom of the wier to increase. By minimizing the weir width as height increases the change in the total flow through the wier as height increases is kept in a linear relationship.
Implementation of sutro wiers in currently operating plants is infeasible due to restrictions of shape and space. Therefore we are approximating the sutro wier with a riser pipe added onto the pipes that connect the initial grit chamber (entrance tank) and the flocculation tank. The pipe would be easily introduced into previously constructed plants and new plants at low cost. Holes would be drilled into the riser pipe that would mimic the sutro wier basics of design. The water is forced to flow through the riser pipe in order to leave the entrance tank and enter the flocculation tank.