AUTOMATIC INDUSTRIAL CROSS-CORRELATOR FOR FLOW MEASUREMENT

The cross-correlation flow measurement technique is a promising method in the two phase flow measurement field. Further research is conducti ng to utilize this technique in the measurement in paper industry. Emp hasis is placed on the design of the polarity correlator for flow meas urement, the accuracy of metering and the analysis of correlator chara cteristics. The paper presents a state-sequenced polarity structure of the simple digital correlator with variable length pre-delay based on a sophisticated microprocessor. The dynamic data tracking feature aut omatically adjusts clock of the hardware and time constant to compensa te for rapid fluctuations in flow rate. The variable length pre-delay expands the flow velocity range to be measured and saves the calculati on time. Finally the paper also presents the test that the ultrasonic flowmeter including an ultrasonic double sensor and the correlator ope rated in a 33.7 mm diameter tube in which pulp suspension was flowing. The experiment indicates that the cross-correlation velocity is linea rly proportional to the reference flow velocity measured by magnetic f lowmeter. All the designed automatic features operated satisfactorily.