ULTRASONIC FLOWMETER

• Main Authors: SHINGU TAKESHI, IWAO KENJI, TAKAHASHI FUTOSHI, FUJISAWA KAZUYA, SAITO TETSUAKI
• Format: Patent
• Language: English
• Published: 28.04.2011
• Subjects: MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; METERING BY VOLUME; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To efficiently perform maintenance work of an ultrasonic flowmeter by automatically determining the degree of contamination (deposits) on a transmitting and receiving surface of an ultrasonic sensor. SOLUTION: A flow rate operation circuit 70 of an operation unit 50 outputs ultrasonic transmission signals c, d to the respective ultrasonic sensors 8a, 8b or 8a', 8b' in flow rate measurement. Reception signals a, b output from the respective ultrasonic sensors 8a, 8b or 8a', 8b' are input to an auto gain adjustment circuit 60. The auto gain adjustment circuit 60 amplifies a signal voltage v of the reception signals a, b so that the signal voltage v reaches a prescribed voltage value when a decrease in the signal voltage v of the reception signals a, b below the prescribed voltage is detected. An amplification factor (gain g) output from the auto gain adjustment circuit 60 is input to a sensor state detection circuit 110, and the sensor state detection circuit 110 determines that reception sensitivity of the respective ultrasonic sensors 8a, 8b, and 8a', 8b' has dropped to not more than a setting value (threshold) and outputs a warning signal when the input amplification factor is larger than a prescribed amplification factor. COPYRIGHT: (C)2011,JPO&INPIT