VorTek U44 Series, Инструкция по эксплуатации

Страница: 19 / 46

Series U44 Instruction Manual
M-000-00090
19
Adjust the transducer to the best position and check to ensure that enough sonic coupling compound was
applied during installation to obtain the maximum signal strength.
The system normally requires a signal strength over 75.0, which is detected from both upstream and
downstream directions. If the signal strength detected is too low, the transducer installation position and the
transducer mounting spacing should be readjusted and the pipe should be reinspected. If necessary, change
the mounting method to the Z method.
2.5.2 Signal Quality (Q Value)
Q value is short for Signal Quality (displayed in the Diagnostics Menu). It indicates the level of the signal detected.
Q value is indicated by numbers from 00 ~ 99. The 00 value represents the minimum signal detected while 99
represent the maximum. Normally, the transducer position should be adjusted repeatedly and coupling compound
application should be checked frequently until the signal quality detected is as strong as possible.
2.5.3 Total Time and Delta Time
"Total Time" and "Delta Time", which display in the Diagnostics Menu, indicate the condition of the installation.
The measurement calculations in the flow meter are based upon these two parameters. Therefore, when "Delta Time"
fluctuates widely, the flow and velocities fluctuate accordingly. This means that the signal quality detected is too
poor. It may be the result of poor pipe installation conditions, inadequate transducer installation, or incorrect
parameter input.
Generally, "Delta Time" fluctuation should be less than
±
20%. Only when the pipe diameter is too small, or velocity
is too low can the fluctuation be wider.
2.5.4 Transit Time Ratio
Transit Time Ratio indicates if the transducer mounting spacing is accurate. The normal transit time ratio
should be 100 +/- 3 if the transducers were installed properly. Check it in the Diagnostics Menu.
Attention
If the transit time ratio is over 100 ± 3%, it is necessary to check:
(1) If the parameters (pipe outside diameter, wall thickness, pipe material, liner, etc.) have
been entered correctly,
(2) If the transducer mounting spacing is in accordance with the display in the Calibration
Menu,
(3)
If the transducer is mounted at the pipe’s centerline on the same diameter,
(4) If the scale is too thick or the pipe mounting is distorted in shape, etc.
2.5.5 Warnings
Pipe parameters entered must be accurate; otherwise the flow meter will not work properly.
During the installation, apply enough coupling compound to stick the transducers onto the pipe wall. While
checking the signal strength and Q value, move the transducers slowly around the mounting site until the
strongest signal and maximum Q value can be obtained. Make sure that the larger the pipe diameter, the more
the transducers should be moved.
Check to be sure the mounting spacing is in accordance with the display in the Calibration Menu and the