Ultrasonic flow meter for measuring flow rate of fluid, has calculating unit deriving difference values between series, where flow rate of fluid is derived based on speed and cross sectional area of conduit

摘要

#CMT# #/CMT# The flow meter has two ultrasonic vibrating units (2, 3) provided on upstream and downstream sides of a conduit (1), respectively to generate backward and forward ultrasonic wave signals. An analog to digital converter (7) converts the signals into backward and forward digital data series. A calculating unit derives total sums of absolute difference values between the series. An ultrasonic propagating time difference is derived based on the value. A flow speed is derived from the difference. A flow rate of the fluid is derived based on the speed and a cross sectional area of the conduit. #CMT#USE : #/CMT# Used for measuring a flow rate of fluid flowing through a conduit. #CMT#ADVANTAGE : #/CMT# The flow meter accurately detects the transit time difference of ultrasonic waves by a simple calculation within a short time period, thus increasing the number of measurements within a unit time period, and hence carrying out the calculation by a less expensive low speed signal processing unit. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a block diagram of an ultrasonic flow meter. 1 : Conduit(2, 3) Ultrasonic vibrating units 4 : Multiplexer 5 : Transmitting amplifier 6 : Variable gain amplifier 7 : Analog to digital converter 8 : Data bus 10 : Random access memory 11 : Central processing unit.