[vidiots]

Since there were some questions about my questimate as to how much the fluid head level effected the flow rate and my figuring of more head height being better, I desided to put my thoughts to the test.

I used a gravity feed drip system to conduct the test. First I mounted the reservoir 5.5" above my sump and adjusted the drip rate which remained at the same setting for the remainder of the tests. I measured the drip rate using a stop watch in drips per minute, with the reservoir low on fluid and again with the reservoir full of fluid. A change in fluid level in the reservoir bottle of about 4 inches.

Second I mounted the bottle at a height of 29 inches above my sump and repeated the above test.

The results suprised me a little. Instead of there being a 1:1 corelation between a percent change in head height to percent change in flow rate the corelation was about 1:2. This means that a 10% decrease in Height above the sump decreased the flow rate by about 20%. However I was dead on with the asumption that having the bottle mounted higher results in a much smaller difference in the empty versus full flow rate.

I have desided with these results that I am going to keep my bottle at the 29" height. The % change in flow rate at this height is about 25% Empty versus full reservoir. I figure I will just measure the two after setting it, and average them and should be able to keep my dose rate constant to within ±12.5%.

If I were to keep my bottle at the 5.5" height my dose rate would vary by ±30% of the average.

Hope this information is useful to those designing their own auto dosers.