Selection of level gauge
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The equipment has water pockets for which it is necessary to measure the level. The floating ball level gauge currently in use has a measurement range of 40 cm; the medium densities specified during design were 0.85 g/cm3 and 1.0 g/cm3. Due to fluctuations in the process operations, the density of the medium has increased to around 0.93 g/cm3. I would like to ask if there are any suitable level gauges available for measurement.
A density difference of 0.1 is essentially the limit for conventional float measurements. The density difference is now 0.07; is the interface measurement accurate? An alternative measurement principle can be used, such as capacitive sensing; however, within a range of 40 CM, the differences in capacitance are too small, making it impossible to obtain an analog output – only a switch function is possible. If the drainage is not continuous (it generally isn’t), switch operation is acceptable.
Please provide a detailed description of the process, such as what the process medium is, what is on the upper layer, and what is on the lower layer? What is the temperature? What is the pressure?
Okay, thank you. It’s a continuous operation here. Now, after calibration, the error is within 20%, which is used as a reference for the manufacturing process.
The process medium consists of: the upper layer contains mainly sec-butyl acetate, along with small amounts of alcohols and trace amounts of acetic acid, while the lower layer is water； The pressure is around 15 KPa, and the temperature is 40°C.
The density difference is too small, and the measurement range is limited as well; double flanges definitely won’t work. Radio frequency admittance might be an option, but the dielectric constant of dibutyl acetate is unknown, so that’s also uncertain. The last option is a magnetostrictive interface detector, but I’m not sure either whether such a small density difference can be measured with it
The density difference is too small, resulting in a limited measurement range; considering the characteristics of various type of interfacemeters, it seems that an external float is the more suitable option.