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KATflow 230
Clamp-on transit-
time flowmeter
Measuring principle
2 Introduction
The KATflow 230 is a portable, battery operated ultrasonic flowmeter employing
clamp-on sensors for the measurement of liquids in full, enclosed pipes. Flow
measurements can be undertaken without interruption of the process or interfer-
ence with the integrity of the pipeline. The clamp-on sensors are attached to the
outside of the pipes. The KATflow 230 uses ultrasonic signals for the measure-
ment of the flow, employing the transit-time method.
Ultrasonic signals are emitted by a transducer installed on a pipe and received by a
second transducer. These signals are emitted alternately in the direction of flow and
against it. Because the medium is flowing, the transit time of the sound signals
propagating in the direction of flow is shorter than the transit time of the signal
propagating against the direction of flow. The transit-time difference T is meas-
ured and allows the determination of the average flow velocity along the path of
acoustic propagation. A profile correction is then performed to obtain the average
flow velocity over the cross-sectional area of the pipe, which is proportional to the
volumetric flow rate.
Illustration 1: Clamp-on ultrasonic sensor configuration
Illustration 2: Transit-time measuring principle
2 Introduction
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