6 Installation
6.2 Transducers
FLUXUS G809
2020-06-25, UMFLUXUS_G809V2-2EN
32
6.2.2
Mounting of damping mats
Before mounting the transducer mounting fixture, damping mats are applied.
• Ultrasonic waves do not only propagate in the fluid but also in the pipe wall. Transducer damping mats are mounted to
counteract the propagation of ultrasonic waves in the pipe wall.
• Ultrasonic waves are reflected at reflection points (e.g., flanges). Pipe damping mats are mounted to reduce the ampli
-
tude of the reflected ultrasonic waves.
• Depending on the transducer type, it can be necessary to mount several layers of damping mats.
6.2.2.1
transducer damping mats
Transducer damping mats are mounted lengthwise on the pipe.
The mounting depends on the outer pipe diameter:
• < 900 mm: The transducer damping mats are mounted on the entire pipe circumference.
• > 900 mm: The transducer damping mats are only partially mounted on the pipe.
The transducer mounting fixture is mounted on the transducer damping mats, see Fig. 6.4.
6.2.2.2
pipe damping mats
Pipe damping mats can be mounted on the pipe lengthwise or crosswise. They are mounted on the entire pipe circumfer
-
ence.
Pipe damping mats can be mounted to reduce the propagation of acoustic noise in the pipe wall if it is not possible to keep
the recommended distances to the reflection points.
If the measured SCNR value is > 40 dB, it is not necessary to mount pipe damping mats.
6.2.2.3
Self-adhesive damping mats
• Select the measuring point according to the recommendations in chapter 3.
• Observe the operating temperature of the damping mats, see technical specification, section "Damping mats".
• Determine the pipe area where the damping mats are to be mounted:
– For outer pipe diameters < 900 mm, see page 34.
– For outer pipe diameters > 900 mm, see page 36.
• Clean the pipe area where the damping mats are to be mounted:
– 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.
– Remove any grease or dust. Clean the pipe surface with soap sud.
Fig. 6.4:
Mounted transducer damping mats in reflection arrangement
1 – transducer mounting fixture
2 – transducer damping mats
Fig. 6.5:
Mounted transducer and pipe damping mats in reflection arrangement
1 – pipe damping mats (mounted lengthwise)
2 – reflection point (e.g., flange, weld)
1
2
1
1
2
