GPI QME05, Руководство пользователя, Страница: 4 / 60

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The UFM employs precise, ultrasonic transit-time dif-
ferential method. This method involves installation of
two ultrasonic transducers on the surface of the piping
and their interconnection with the electronic evaluation
system. The ultrasonic transducers operate in alternating
mode as transmitter and receiver with cyclic exchange of
ultrasonic signals. Measurements cover the transit times
of the upstream and downstream signals (t1, t2). The UFM
measures the transit-time differential of the ultrasonic
signals t1 and t2 that travel upstream and downstream.
These signals are accelerated (t1) or retarded (t2). The
difference that develops between both signal transit times
is proportional to flow velocity and is used in combination
with the piping geometry data for precise calculation of
the volumetric flowrate.
FIXED UFM AND COMPONENTS
α
cos 2 2 1
) 1 2 (
⋅ ⋅
−
=
T T
T T
L v
Calculation of flow velocity [m/s]
π
α
⋅ ⋅
⋅ ⋅
−
=
4 cos 2 2 1
) 1 2 ( 2 D
T T
T T
L Q
Calculation of flowrate [m3/s]
The flow transmitter uses a sophisticated cross-correlation
to detect signals. This ensures a reliable detection of
signals even in case of harsh circumstances like gas
and/or particle load.
FIGURE 2: UFM – with Mounted Ultrasonic Transducers (Bottom)
and Flow Transmitters
The UFM consists of the ultrasonic transducers and the
flow transmitter that are mounted onto piping.
FLOW TRANSMITTER
FIGURE 3: Flow Transmitter
The flow transmitter processes the signals and makes
the measurement results available to the user.
ULTRASONIC TRANSDUCERS
The ultrasonic transducers are mounted onto the pip-
ing and transmit and receive the ultrasonic signals
that are used in the flow transmitter to calculate the
volumetric flowrate.
Ultrasonic transducers:
QMF-F10 (1 MHz) for pipe diameters 1.25" to 16"
QMF-F21 (2 MHz) for pipe diameters 3/8" to 4"
Operating temperatures: -40° F to 300° F
FIGURE 4: Ultrasonic Transducers (F10/F21) typically
used with Spacer Bar (not shown)
Ultrasonic transducer:
QMF-F05 (0.5 MHz) for pipe diameters 8" to 240"
Operating temperatures: -40° F to 180° F
(300° F optional on request)
FIGURE 5: Ultrasonic Transducers (Type F05)
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