6 Installation
FLUXUS G809
6.2 Transducers
29
UMFLUXUS_G809V2-2EN, 2020-06-25
6
Installation
6.2
Transducers
6.2.1
Preparation
6.2.1.1
Measuring point selection
The correct selection of the measuring point is crucial for achieving reliable measurement results and a high measurement
accuracy.
A measurement on a pipe is possible if:
• the ultrasound propagates with a sufficiently high amplitude
• the flow profile is fully developed
• the influence of noise is sufficiently low
The correct selection of the measuring point and the correct transducer positioning guarantee that the sound signal will be
received under optimum conditions and evaluated correctly.
Because of the variety of applications and the different factors that influence the measurement, there is no standard solu
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tion for the transducer positioning.
The measurement is influenced by the following factors:
– diameter, material, lining, wall thickness and shape of the pipe
– fluid
• Avoid measuring points in the vicinity of distorted or defective areas of the pipe or in the vicinity of welds.
• Avoid measuring points with deposit formation in the pipe.
• Make sure the pipe surface at the selected measuring point is even.
• Select the location of the transmitter within the transducer cable range.
• The ambient temperature at the measuring point has to be within the operating temperature range of the transmitter and
the transducers, see technical specification.
If the measuring point is within an explosive atmosphere, possibly present danger zones and gases have to be deter
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mined. The transducers and the transmitter have to be appropriate for these conditions.
6.2.1.2
Pipe preparation
Rust, paint or deposits on the pipe absorb the sound signal. A good acoustic contact between the pipe and the transduc
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ers is obtained as follows:
• Clean the pipe at the selected measuring point.
– If present, the paint layer has to be smoothed by grinding. The paint does not need to be removed completely.
– Remove rust or loose paint.
• Install the damping mats.
• Use coupling foil (only if no damping mats are installed) or apply a bead of acoustic coupling compound along the center
line of the contact surface of the transducers.
• Observe that there must be no air pockets between the transducer contact surface, damping mat and pipe wall.
Caution!
Contact with grinding dust
This may result in injuries (e.g., breathing difficulties, skin reactions, eye irritations).
→ Wear the required personal protective equipment. Observe the applicable rules.
Important!
The pipe has to be sufficiently stable to withstand the pressure exerted by the transducers and the tension straps.
Notice!
Observe the selection criteria of pipe and measuring point.
