VorTek SonoPro S34 Series, Инструкция по эксплуатации

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Series S34 Instruction Manual Chapter 1 Introduction
1-3 M-000-00030
How the SonoPro
®
Flow Meter Operates
Velocity Measurement
The SonoPro Portable flowmeter operates on the transit time ultrasonic
measurement method. This type of measurement uses the basic fact that
the fluid's velocity influences the transmission speed of the ultrasonic
signal. This is analogous to a person paddling a canoe with the current
versus paddling against the current. The canoe can travel downstream
with the current faster than it can be paddled back upstream against the
current. The same is true for the sound waves as they travel with and
against the direction of fluid flow.
For the measurement, two ultrasonic transducers are mounted
onto the outside of the pipe. With one being downstream at a designated
distance from the other. The electronics send two pulses through the
pipe and into the fluid inside the pipe. One signal is sent with the direc-
tion of the flow, and the second is sent against the flow. The transducers
act as both transmitters and receivers. The transit time of the ultrasonic
signal moving in the direction of the flow is faster than that sent against
the flow. The meter's electronics read these two times and calculate the
time difference, ΔT, which can then be used to determine the average
flow velocity.
The SonoPro Portable electronics take into account the fluid flow
profile and apply a correction to the velocity reading to determine the
average flow through the pipe.
Ultrasonic Flow Path
Figure 1-1. Ultrasonic Flow Path