Over the course of the semester, our team experienced many technical challenges that impaired our ramp state experimental results.
Upon analyzing experimental results for the ramp state experiments that were run, it was determined that the floc blanket formation time was not long enough to allow for accurate results. (Why is this the case?) Specifically, not enough time was allotted for an ideal floc blanket (What do you mean by an ideal floc blanket?) to form before the ramp state initiated. Since this finding, we have been experimenting with increased floc blanket formation times, approximately 8 hours as opposed to the original 6 hours.
During the semester, our influent water-clay mixer malfunctioned and needed to be replaced and a new mixer was ordered. Until the new mixer was received, our team proceeded with experiments. Without the mixer, greater amounts of clay were required to keep the turbidity of the influent water-clay mixture at 100 NTU. Therefore, our system ran through our clay stock much quicker than normally and the data from these experiments had to be discarded. (I would put in a sentence here about what you would do in the future with this in process control, such as increasing clay stock concentration so you didn't run out.)
In order to get a complete full run for an experiment, we decided to temporarily decrease the ramp time to two hours for our ramp state functions. This created a problem with the smaller tubes because the smaller tubes use lower flow rates in the ramp state function. Because these flow rates are so low, the residence time in both the tube settler and the turbidimeter becomes significant. (Can you show these calculations?) Therefore, when designing future experiments in process controller, it is important to consider these residence times when determining the ramp time. (Please come up with a criteria that you will be using in the theory to do this.)
Our team also experienced several minor problems that significantly affected our experiments. For example, originally our system did not have a drain valve and the floc blanket tube had to be manually drained. Mid-way through the semester a drain valve was installed. (That's not the case. The solenoid valve was not large enough and experienced clogging over time as we drained. We switched over to a manual because of the size of the orifice that would not become clogged) Unfortunately, several experiments were started with the valve not properly closed and thus the experiment could not proceed. We also experienced a number of power failures in our area in the lab which had to be fixed by someone with a better knowledge of this problem.