Patent ID: 6622572
Filing Date: 2003-09-23
Classification: G01F

Abstract:
An ultrasonic flowmeter comprising:(a) a pair of ultrasonic transducers mounted on an outer surface of a flow tube at an upstream side and a downstream side respectively, a switching device for switching the operational mode of each of the pair of transducers alternatively to its transmitting or receiving mode, an amplifier for amplifying the signal received by the ultrasonic transducer of the receiving side and representing the ultrasonic waves propagating through the fluid, and a data reduction equipment for processing the amplified received signal to output a flow rate signal; (b) the amplifier including an amplification gain control terminal, wherein an amplification gain is adjusted on the basis of a control signal input into the terminal; (c) said data reduction equipment including an analog-digital converter, a processor, and a memory, wherein waveform data are converted into digital data: the waveform data, comprising analog data including a peak value of each of the received signals generated together with a plurality of transmission and reception, and the obtained digital data are stored in the memory; (d) wherein said processor screens the peak values stored in the memory to obtain as an attenuation free peak the value achieved on the fluid without impurities, compares the obtained peak value with a preset peak value preliminarily set in the processor, sends a control signal to the gain control terminal of the amplifier on the basis of the result of the comparison, and controls the peak value included in the output signal of the amplifier so as to take a substantially equal value as that of the preset value of the peak.