The localization of the hottest pressure sensor is

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The localization of pressure sensors is imminent

pressure transducers, especially differential pressure transmitters, are widely used in China's petrochemical industry. The vast majority of transmitter sources rely on imports, which is not only expensive, but also likely to hide potential threats due to the lack of independent intellectual property rights. Energy security is related to national security, so localization of sensors is imminent

at present, MEMS pressure transducers used in transmitters produced by foreign manufacturers mainly have piezoresistive and capacitive structures, most of which are piezoresistive structures. Siemens DSM series pressure transmitter is a pressure sensor with piezoresistive structure. The sensor chip of American Rosemount 3o51 series pressure transmitter is also of piezoresistive structure. Piezoresistive sensors are widely used. Many domestic manufacturers rely on imported piezoresistive sensors to manufacture domestic transmitters according to 028w/mk. Piezoresistive sensor technology is mature, which is very suitable for domestic development. However, piezoresistive sensors are easily affected by environmental factors such as temperature and humidity, and the static pressure characteristics depend on the process level, which cannot be guaranteed. These two difficulties limit the measurement accuracy and stability of domestic piezoresistive sensors

a few enterprises represented by Fuji company have produced pressure transmitters with silicon capacitance sensors as the core, with a price of more than 30000 yuan per ton. Capacitive pressure sensor has the advantages of high precision and good long-term stability. However, it has high requirements for production technology and is difficult to process. The research of silicon capacitance pressure sensor in China is just beginning. Although some domestic units have developed silicon capacitance sensors, whose accuracy and static pressure characteristics are close to the average level of Fuji products, there is a large gap in long-term stability. At the same time, there is still a big gap in the development of high differential pressure and micro differential pressure specifications for domestic capacitive sensors. The accuracy of foreign piezoresistive sensors can reach 0.075%, while the accuracy of domestic piezoresistive sensors is only 0.1%. In terms of long-term stability, the gap between domestic sensors and imported sensors is more obvious. The index of long-term stability of domestic products is 0.1% per year, which is at least 2 times higher than that of foreign products. In addition, the temperature characteristics of domestic products are poor. Compared with foreign products, the temperature drift is larger than the typical value of foreign products. The scribed line on the support is 50% - 100% of the position of the idler centerline. In addition, the specifications and varieties of domestic products are not complete, and there are no mature products in terms of micro differential pressure, high differential pressure and high static pressure specifications, which cannot meet the special requirements of some processes

The key to the localization of pressure sensor is how to improve the long-term stability of the sensor. The long-term stability of the sensor is closely related to the material selection, structural design and processing technology of the sensor. China is still in a relatively backward stage in terms of MEMS processing technology in the development of Ningbo new material industry. Improving the process level is undoubtedly a long-term plan to improve the performance of sensors

at present, relevant domestic universities and scientific research institutions have carried out a lot of research on piezoresistive and capacitive MEMS sensors, and have made a number of achievements in theory and technology. In terms of the current process level, if some form of compensation or self calibration method can be realized, it is possible to improve the long-term stability of the sensor in the short term, so that the domestic sensor can meet the needs of the petrochemical industry in terms of stability indicators. Therefore, on the basis of domestic MEMS Research, through the cooperation of scientific research institutes and factories, the localization of pressure transmitters required by the petrochemical industry can be achieved

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