KROHNE UFM 600T EN - Manual (Page 89)

ALTOSONIC
Appendix
86
APPENDIX 3 : Sonic velocity calculation Using Indicated
Transit Time
Start
Measuring
Mode
Check
indicated
trans-
ducer
Restart
procedure
Install transducers using
Sonic Velocity of Water 1500
m/s
Look at "Low Signal Marker"
to set the correct Transducer
Distance
Correct the Transit Time (TT)
for delay in the
pipewall to find the
True Transit Time (TTT)
Calculate
Y =
Pipe Inner Diam.
True Transit Time
Calculate
Sonic Vel. = 1054 * Y
Program calculated
Sonic Velocity
See upper left corner of the display
Transit Time should be on display,
see fct. 3.2.5.
For Stainless Steel and (Cast) Iron:
TTT = TT - 0.8 * t - 7.6
For plastics:
TTT = TT - 1.2 * t - 7.6
with:
TTT = True Transit Time in [us]
TT = Indicated Transit Time in [us]
t = Pipe wall Thickness in [mm]
With:
- Pipe Inner Diameter in [mm]
- True Transit Time (TTT) in [us]
With:
- Sonic. Vel. in [m/s]
Read the Transit Time value
indicated in the display
difference
≥ 5 mm
difference
< 5 mm
UFM 600 T