Mass flow sensors

Air mass flow sensors can be used in fans and vacuum cleaners. 

Fj, F2, Brooks Instruments Model No. 5812 mass flow sensor and... 

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. 

Mass-flow sensors are used to measure air intake. Their advantage over pressure sensors in the same application is primarily higher accuracy. The growth of this sector is moderate and mainly due to increasingly strict environmental legislation. 

A wide range of manufacturers use various technologies (heated wire, ceramics, silicon). The market for mass-flow sensors was estimated as about 800 million in 2000. 

For discrete micromechanical devices that do not include integrated electronics, the situation is different Platinum is an excellent choice for sensors based on a thermal measurement principle and is used in very high volumes, for example, in the air mass flow sensor chip produced at Bosch. Here, a platinum thin film serves as both a heater and a temperature sensor on a thin dielectric membrane consisting of silicon oxide and silicon nitride. The advantages of platinum as a thin film for thermal sensors compared to, for example, polysilicon are as follows ... 

Mass Flow Sensors Extraction of Thermal Material Properties... 

From the vantage point of microfluidics, the structures developed by Petersen et al [33] are the most appropriate. More recently, Baltes and coworkers combined CMOS circuitry with the microfabrication of sensors to construct a thermal mass flow system based on thin-film pyrometers [66]. As free standing mass flow sensors, they have attractive features. However, all of these silicon-based devices operate at relatively high temperatures in the 100-200 °C range. This elevated temperature limits their potential application in more complex microfluidic systems. The ideal flow sensor would be a very-low-temperature element that could be used on the walls of the microchannel. 

Figure 12.6 (a) An exploded view of a microchannel PA. The anemometer chip is secured in the wall of the channel with epoxy, (b) Experimental data comparing the response of the PA chip in the microchannel to flow with corresponding data taken with an MKS 100 thermal mass flow sensor. 

Typical Coriolis mass flow sensor geometry. 

Air Loop Air compressor/ expander Air mass flow sensors Air throttle body Air humidifier Air compressor/ expander Air mass flow sensor Air humidifier... 

We have developed a novel, highly-sensitive air or gas flow sensor which performs well as a mass flow sensor and differential pressure sensor. It is especially suited to applications in the low differential pressure range from 0 to 1.0" of water colunrn. 

It provides a more direct approach for temperature and pressnre compensation than other presently-available mass flow sensors requiring measurement of temperature and pressure. For some gas mixtures of varying composition, mass flow is indicated accurately (e.g. CO2 and He) without calibration corrections. Because it can be fabricated by conventional thin film deposition and silicon processing techniques. It offers the possibility of lower cost and broader applications than present conunercially available gas flow sensors. 

The system uses MSP430F149 do give priority to the controller, cooperate with FS4001 gas mass flow sensor complete the gas content test. The whole function circuit includes MCU module, ferroelectric storage module, clock module, keyboard module, LCD display module, USB communication circuit module unit (Ji Liming 2010). 

Flow Rate Measurements, Methods, Fig. 5 Photomicrograph of a microfluidic mass flow sensor [1]... 

Nguytm NT (1999) Thermal mass flow sensor. In WebslCT JG (ed) Mechanical variables measurement solid, fluid, and thermal. CRC Press, Boca Ratrai... 

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