Multi-Sensor Temperature and Humidity Measuring System for Technological Process of Organic Livestock Waste Microwave Treatment Monitoring

In this paper we consider the issues of multi-sensor system design for measuring temperature and humidity during organic livestock waste (OLW) microwave treatment. The “brains” of OLW microwave treatment are concentrated in mathematical model. Changes in the dielectric properties of the medium being processed are taken into account in the function of heat losses, which depend on the spatial variable and time. Temperature and humidity of medium in moment are the input data for model. OLW humidity content is a key determinant of the quality of the output product (fuel briquettes), therefore, controlling humidity and temperature during treatment can significantly improve the overall efficiency of the microwave treatment. There are various methods and means for measuring humidity and temperature used in the practice of industrial processing of various nature media. One of the widespread methods is the microwave dielectric method for measuring humidity, based on the characteristic interaction of humidity distributed in an object with an electromagnetic field of the microwave range. The use of the microwave dielectric method for measuring humidity in the process of conveyor microwave treatment, when it is possible to organize separate control zones and electromagnetic influence, opens up a number of promising possibilities, the main of which is the use of the measured complex dielectric constant in the adaptive control circuit of the microwave treatment installation. The effect of local measurement of the dielectric constant, implemented in the developed sensor, makes it possible to build on its basis quasi-distributed multi-sensor systems for a more informative determination of the OLW humidity. The use of addressable fiber Bragg structures in conjunction with microwave sensors allows us to create a multi-sensor humidity and temperature control. In this case, the data of each humidity sensor grouped with the data of an addressable temperature sensor, which indicates the location of the control point and allows visualization of temperature and humidity field distributions in OLW.