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This semester I will be working with Stock Tank Mixing Team. I am supposed to invest my time in finding an appropriate hydrometer that can measure the concentration of the stock and can easily be transported to Honduras. I am also supposed to work on the stock tank centrifugal pump which will ensure that the plant operator can prepare a homogeneous solution in the stock tank.
Hydrometer
We have already purchased the Krackeler Scientific Hydrometer which is easy to handle and can be transported safely to Honduras. We tested the hydrometer twice with PACl from Honduras for its consistency and once with sugar solution. More testing of the hydrometer is scheduled and once it is complete we will be able to make a conversion chart suitable for the operator.
Stock Tank Centrifugal Pump
concluded Krackeler Scientific Polycarbonate Hydrometer with range 1.000-1.220 to be the most appropriate equipment to measure the PACl solution concentration in an AguaClara plant. We have purchased three of them to be sent to Honduras with the students in January 2014. The conclusion was reached at after performing several tests using Honduran PACl to determine the relationship between the concentration and density. This relationship helps convert the specific gravity reading from the hydrometer to its corresponding density value. The relationship is: Density PACl = 0.492*(Hydrometer Reading) + Density of Water.
For the chlorine solution the specific gravity range is quite small, which requires a very precise hydrometer. At the same time, durability is still the biggest deciding factor and no polycarbonate hydrometer with the desired range (1.012 being the max) is available. For the testing purposes during spring 2014, we have purchased a Cole Parmer (1.000-1.050) glass hydrometer to conclude if we should invest our time in getting a polycarbonate hydrometer of desired range manufactured.
Stock Tank Centrifugal Pump
The fabrication of the pump is almost over. We used the design from last year's coagulant management team and improved it. It involved replacing the brass joint at the bottom with 1/2" PVC plate that sits at the bottom of the tank. A PVC t-joint is connected to the plate using two stainless steel screws, this provides the stability to the base of the pump which was a challenge faced by the coagulant management team. We will be using used a wooden piece that fits at the top of the tank through which the pump passes; this will make makes the pump totally stable. This wooden piece is yet to be fabricated. Once the fabrication process is done we will begin testing to gain a better understanding of the pump's performance.We used sugar solutions of various concentrations and used red dye to distinguish from less dense water to perform the pumping tests. After the several tests, we have concluded that the current design is extremely inefficient because of the major loss of input power due to the drag caused on the rotating arm. For next semester the team will work on fabricating a streamline arm to reduce the drag coefficient. We will also invest some time in exploring new ideas that can be used to make an efficient centrifugal pump.