Katronic Technologies FLUXUS ADM 6725, Operating Instruction

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ADM 6725 E10
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KA T
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Functional Description
1 Functional Description
1.1 Measuring Principle
FLUXUS utilises ultrasound for the measurement of liquid flow, employing the so-called
transit time method. The instrument measures the drift of ultrasonic signals resulting
from their travel through the flowing liquid. The ultrasonic signals are transmitted
alternatively with the direction of flow and against it.
The flowing medium causes different transit times of these two sound signals. From the
time difference, FLUXUS identifies the average flow velocity along the path of acoustic
propagation. Through a flow profile correction, FLUXUS calculates the average flow
velocity with reference to the cross sectional area, which is proportional to the volume
flow.
This effect can be observed over the complete range of flow velocities found in technical
applications. This allows FLUXUS to cover a wide flow measuring range and also to
determine the direction of flow within the pipe.
Ultrasonic waves also propagate solid materials. Thus, the transducers (alternatively
operating as sound transmitters and receivers) can be mounted onto the outside of
pipewalls. FLUXUS makes use of that possibility, so that the installation is very easy and
can even be performed while the process is in operation. In order to avoid wrong
measurements, FLUXUS, with its special electronics, tests the incoming ultrasonic signals
for their usefulness for the measurement and evaluates the plausibility of the measured
values.
The microprocessor integrated in FLUXUS controls the complete measuring cycle,
eliminating disturbance signals by statistical signal processing techniques.
Flow disturbance sources within the pipe system, e.g. slide valves, elbows, pumps or
other flow elements, distort the flow profile and, therefore, may influence the measuring
result. Thus, certain minimum distances from the selected measuring point to the
disturbance source should be observed.
FLUXUS has in-built facilities to help the user to select the correct transducer position on
the pipe.
1.2 Operating Conditions for FLUXUS
FLUXUS, in comparison with other well-known principles of flow measurement, offers a
range of advantages. These stem from the ultrasonic measuring principle, employing the
transit time method in conjunction with clamp-on transducers.
FLUXUS can always be used where the pipewall and the liquid to be measured are
sonically conductive. This is true for pipewalls consisting of homogeneous material, and
for liquids, which carry only a certain amount of solid particles or gas bubbles. There is