The Research Of Pulp Concentration Detection System Based On The Ultrasonic Attenuation

The concentration detection technology of slurry has been widely used in the industrial producing. About the paper pulp which is a kind of liquid-solid two-phase suspension consists of liquid water and paper fiber, over the years in order to meet the needs of production and research have developed many kinds of off-line measurement of pulp concentration. But with the degree of automation of industrial production process being improving, these methods obviously cannot meet the actual production requirements. This paper aims to explore a kind of on-line measurement system of pulp concentration which can meet the practical application.With the constantly updated and improvement of signal processing methods here and abroad. The ultrasonic detection technology, as a new measurement method, with its special advantages is favored in the slurry concentration detection. There are some main advantages of this method:only need some sample equipment, real-time on-line monitoring, fast measurement speed, high precision, strong anti-interference ability, quiet and no noise pollution, and can work under severe environmental conditions.Ultrasonic testing technique is the use of a special relationship between the acoustic properties of the physical and media to achieve concentration measurement. This article selects the ultrasonic attenuation method to measure the pulp concentration. through the theoretical research and analysis, it’s found that in certain range of frequency, the attenuation of ultrasonic wave amplitude is proportional to the size of concentration. Therefore, through the attenuation coefficient of amplitude can measure the density. The method of feasibility and rationality has been proved through the analysis and verification.The heart of ultrasonic measurement of concentration is part of ultrasonic signal transmitting and receiving. Through the analysis of traditional single-chip microcomputer control methods, due to the time delay error and low accuracy of shortcomings, we put forward FPGA as the control chip design the hardware system. As a kind of high density programmable device, FPGA has fast speed and abundant internal resource, which provides a new solution for the development of high-performance concentration of ultrasonic measurement system.Finally, through the analysis of the feasibility research, It’s proved that the system which based on FPGA as the control chip has reduced the development cost and improved the accuracy of measurement. The system can realize the fast accurate on-line measurement of pulp concentration.