Sensors Micro Coriolis

Figure 8.10 Micro Coriolis sensor prototype. Miniaturized structure of tubular resonator on the test bed.

Haneveld, (., Lammerink, T.S.J., Dijkstra, M., Droogendijk, H., de Boer, M.J., and Wiegerink, R.J. (2008) Highly sensitive micro coriolis mass flow sensor. IEEE 21st International Conference on Micro Electro Mechanical Systems, 2008. MEMS 2008, pp. 920-923. 

R 18] [A 1] Each module is equipped with a heater (H3-H8) and a fluidic cooling (C03-C06). Temperature sensors integrated in the modules deliver the sensor signals for the heater control. Fluidic data such as flow and pressure are measured integrally outside the micro structured devices by laboratory-made flow sensors manufactured by silicon machining. The micro structured pressure sensor can tolerate up to 10 bar at 200 °C with a small dead volume of only 0.5 pi. The micro structured mass flow sensor relies on the Coriolis principle and is positioned behind the pumps in Figure 4.59 (FIC). For more detailed information about the product quality it was recommended to use optical flow cells inline with the chemical process combined with an NIR analytic or a Raman spectrometer. 

Figure 3 shows the test section and instrumentation. Ten wall temperatures on the tube external surface were measured with 0.5 mm diameter calibrated type E thermocouples electrically insulated from the aluminium. Fluid inlet and outlet temperatures were measured with 1 mm diameter calibrated type K thermocouples. Cah-bration was carried out with a Rosemount 162-CE platinum thermometer. Due to the high thermal conduchvity of the aluminium and the low thickness of the tube walls the measured temperature is very close to the wall temperature in contact with the fluid (the difference less than 0.01 K). The inlet fluid pressure was measured with a calibrated Rosemount type 11 absolute pressure sensor. Two calibrated differential pressure sensors measured the pressure loss through the test section. A Rosemount Micro-motion coriolis flowmeter was used to... 

This is necessary both for process control as well as the reliabihty of the system. The integration of sensors into the microreactor or building a multisensor module for the four functions of state is easy for a microreactor made of sUicon. For the process pressure, the piezoresistive principle is used often. With diEFerential pressure measurements, the flow rate can be determined. Alternatively, calorimetric principles are used widely. These are easy to implement technically, but a calibration is needed for eatii new medium. The most robust sensors are the Coriolis mass flow sensors. In process engineering, they are very common, but in terms of micro process engineering, there is still a need for research. In Ref. [26], sensors of this type are described. Ref [25] is a good summary of other microflow sensors. For measurement of temperature, there are many equivalent principles but will not be discussed here. Substantially, it is more difficult to measure the concentration in the reactor. In addition to optical principles, the impedance spectroscopy is often used. See Ref [27-31] for more details. 

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