Abstract:
Objective The non-contact measurement of ethanol concentration represents a novel approach to concentration measurement, offering significant advantages for specialized industries such as medical, wine, and industrial alcohol. To facilitate non-contact ethanol measurement, a dedicated ethanol concentration measurement system has been designed based on the characteristics of infrared spectrometry. This system enables continuous and contactless measurement of varying concentrations of ethanol.
Methods In the context of ethanol, the spectral characteristic response is highly sensitive in the 1,300-1,350 nm range of the near-infrared band. Therefore, an infrared LED light-emitting diode emitting in this band is employed as the light source, and a photodiode sensitive to this band is chosen as the receiver. When exposed to light, the photodiode generates a weak reverse current, which is then converted into a voltage signal by the transimpedance amplifier. Subsequently, an A/D converter chip is utilized to collect the voltage signal. Using this system, the relationship between ethanol concentration and the voltage signal can be determined by measuring different concentrations of ethanol. Consequently, the ethanol concentration value can be obtained by measuring the corresponding voltage value.
Results and Discussions The experiment demonstrates a robust quadratic function relationship between the voltage and ethanol concentration in the infrared band. The results reveal a high correlation coefficient of 0.999 11, with an average absolute error of 0.64. This level of error is comparable to that of traditional ethanol measurement devices (0.5), affirming the feasibility of the device. Further optimization of the circuit and program has the potential to reduce errors. Compared to traditional measurement methods, this approach boasts advantages such as a simple structure, faster operation, and the capability for continuous measurement.
Conclusions The device designed for measuring ethanol concentration holds significant value in various industries such as winemaking and medicine, where precise measurements are crucial. Its non-contact measurement capability ensures that the product remains undamaged during the testing process. Moreover, the device's continuous detection capability is particularly advantageous for industries requiring real-time monitoring. With further enhancements, there is potential for achieving automated detection, adding another layer of efficiency to the measurement process.
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