5 Selection of the Measuring Point FLUXUS G60x
UMFLUXUS_G6V4-2EN, 2011-03-29 27
Measuring point at a distance of l
S
± 2 D from the reflection point
Pipe wall signal and measuring signal are received by the transducer at the same time.
l
S
- distance to the reflection point
D - outer pipe diameter
c
F
- sound speed in the medium
c
P
- sound speed in the pipe
n - number of sound paths
example:
medium: natural gas
pipe material: stainless steel
c
P
: 3000 m/s
c
F
: 400 m/s
number of sound paths: 2
l
S
= 7.5 D
The area (7.5 ± 2) D is disadvantageous for the transducer installation.
Tab. 5.3: Measuring points to be avoided