ULTRASONIC FLOWMETER

To provide an ultrasonic flowmeter having a high degree of freedom of circuit design and having high sensitivity and few errors.SOLUTION: An ultrasonic flowmeter (10) comprises: an upstream-side transmission sensor (12) and a downstream-side transmission sensor (13) for transmitting an ultrasonic pulse toward fluid (14); two receive sensors (15, 16) sequentially attached in a flow direction of the fluid of a conduit (11) between the upstream-side and downstream-side transmission sensors; a time difference measurement unit (25) for measuring a time difference between received signals of two receive sensors; and a computation unit for calculating a flow rate of the fluid on the basis of a time difference when ultrasonic pulses are transmitted from the upstream-side transmission sensor and a time difference when ultrasonic pulses are transmitted from the downstream-side transmission sensor. Each of the two receive sensors receives an incident ultrasonic pulse and outputs a received signal, as well as reflects an ultrasonic pulse toward the other receive sensor arranged immediately next to one.SELECTED DRAWING: Figure 1 【課題】回路設計の自由度が高く、高感度で且つ誤差が少ない超音波流量計を提供すること。【解決手段】超音波流量計（１０）は、流体（１４）に向って超音波パルスを送信する上流側送信センサ（１２）及び下流側送信センサ（１３）と、管路（１１）の、上流側送信センサと下流側送信センサとの間に、流体の流れ方向に沿って順次取り付けられた、２つの受信センサ（１５、１６）と、２つの受信センサの受信信号の時間差を測定する時間差測定部（２５）と、上流側送信センサから超音波パルスを送信したときの時間差及び下流側送信センサから超音波パルスを送信したときの時間差に基づいて流体の流量を算出する演算部と、を具備する。２つの受信センサは、各々、入射された超音波パルスを受信して受信信号を出力すると共に、一つ隣に配置された他の受信センサに向って超音波パルスを反射する。【選択図】図１