The key to affecting the life of the heat meter is the ultrasonic sensor.
Researcher of the Institute of Physics of the Chinese Academy of Sciences, member of the Expert Committee of the Ministry of Housing and Urban-Rural Development of China, and Professor Wang Shuzheng of the Technical Committee of the China Urban Heating Association conducted a preliminary investigation on the heat meter ultrasonic flowmeter used in China, and measured and analyzed a representative batch of ultrasonic waves. Static parameters of the energy device. The result is worrying!
At present, almost all thermal meter companies in China have begun to develop and produce ultrasonic heat meters. From the dozens of relevant scientific research results reported to the Ministry of Housing and Urban-Rural Development in the past two years, most of the research focuses on the design of the basic mechanical structure of the flowmeter (including the reflector and the measuring tube section), and only a small amount of sensor output is involved. Signal processing; research on the performance of ultrasonic transducers is generally ignored, and some companies even lack the necessary understanding of the main technical parameters.
First of all: about 60% of the heat meter companies did not propose sufficient comprehensive technical performance parameters when purchasing ultrasonic transducers. More than half of the ultrasonic transducer manufacturers provide obvious technical parameters; or too simple, the main parameters are not provided; or the name is not true, the measured results are highly biased.
For example: Almost all heat meters Ultrasonic flowmeter transducer center frequency is nominally 1MHz. The measured results are: only 30% reach 1MHz (1000KHz) 5%; the maximum deviation is more than 12%. It may be considered that if the compensation and pairing can be used on the circuit, the center frequency is not feasible at 1MHz (1000KHz); the problem is that more than 80% of the manufacturers ignore the pairing consistency of other important parameters of the flowmeter ultrasonic transducer; Including: capacitance, conductance, mechanical quality factor, impedance, etc. It should be known that the change of these parameters with temperature will affect the time difference of the ultrasonic wave propagating in water, that is, the accuracy of the ultrasonic flowmeter. Under the same conditions, the measurement results of the five static parameters of the domestic high-quality and imported flowmeter ultrasonic transducer are: center frequency deviation: 1%; other four parameters pairing deviation: 4%; and domestic heat meter flowmeter It is extremely rare for ultrasonic transducers to reach this level. This gap cannot be ignored!
Even for a good base meter and signal processing circuit design, if an inferior and unaged ultrasonic transducer is used, not only does the flow measurement of the heat meter fail to meet the technical requirements, but it may also occur irregularly during the measurement operation. The changes that cannot be compensated are such that the life of the heat meter is shortened.
Black Silicon Carbide,Silicon Carbide,Sic Silicon Carbide,Dry Silicon Carbide
ningxia hexing carbon based materials co.ltd , http://www.hexingsicmanufacture.com