ULTRASONIC CONCENTRATION METER FOR MEASURING SLUDGE DENSITY AND SLUDGE DISPOSAL SYSTEM

The present invention is to provide an ultrasonic densitometer accurately measuring sludge density by switching frequency of the ultrasonic waves according to sludge concentration. A controller (36) is to determine whether sludge concentration has reached the set density value corresponding to the automatic switching change point of frequency. When the controller (36) determines that sludge concentration reaches the set concentration value from high concentration side due to decrease of sludge concentration, the controller (36) automatically converts frequency of ultrasonic waves (S1) sent from a transmission sensor (31) from 1 to 3MHz. Also, when the controller (36) determines sludge concentration reaches the set concentration value from low concentration side due to increase of sludge concentration, the controller (36) automatically converts frequency of ultrasonic waves (S1) sent from a transmission sensor (31) from 3 to 1MHz. [Reference numerals] (33) Ultrasonic wave oscillator; (34) Receiving circuit; (35) Signal amplifier circuit; (36) Controller; (37) Display device; (39) Memory; (AA) Output concentration