Another good manufacturer is Lewa (also German). In states, they can be found at www.amlewa.com. Their Ecodos model ("ECOnomical DOSing"... how's that for German marketing!) is a good, reliable, but not too expensive sealless metering pump.
I was responsible for checking the stability of dip pipes in stirred tank reactors. Our approach was to assume an average velocity across the pipe and use an assumed turbulent regime Strouhal No. (non-dimensional shedding frequency) to calculate the excitation frequency. To be safe, we limited...
