Burkert Flowave 8098, Operating Instructions Manual

Page: 226 / 354

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SAW sensor – Parameter
Type 8098 FLOWave L
15.13 Setting the parameters of the acoustic transmission
factor (optional feature)
15.13.1 What is the acoustic transmission factor?
The acoustic transmission factor makes it possible to know the quality of the transmission of sound in the
liquid thus the reliability of the measurements.
Indeed, the wave transit time in the liquid and the wave amplitude change depending on the following
criteria:
• the type of liquid: aqueous solution, oil solution, emulsion, ...
• the presence of gas bubbles,
• the presence of solid particles,
• the liquid temperature,
• the DN of the pipe.
The acoustic transmission factor, given in %, is calculated on the base of the amplitude changes of the
waves. The acoustic transmission factor of water without gas bubbles is equal to 100 % at a water tem -
perature of +23 °C.
The temperature changes of the liquid are not compensated for the measurement of the acoustic trans-
mission factor.
The device measures acoustic transmission factors from 10 % and up.
• If the wave amplitude in a liquid flowing through the pipe is higher than the wave amplitude in water, the
measured acoustic transmission factor will be higher than 100 %.
• If the wave amplitude in a liquid flowing through the pipe is lower than the wave amplitude in water, the
measured acoustic transmission factor will be lower than 100 %.
Gas bubbles or solid particles in the liquid have a similar effect on the transmission acoustic factor. If
the concentration of gas bubbles or solid particles increases in a liquid, the acoustic transmission factor
decreases. So, measuring and monitoring the acoustic transmission factor can be used to detect the
presence of gas bubbles or solid particles in the liquid.
→
Take into account that special process conditions can have an effect on aging of the sensor thus on the
acoustic transmission factor value.
15.13.2 Giving a user defined name to the measured acoustic
transmission factor
The name is used to identify the process value in the user defined views and in all the menus where the
process value is displayed (for example in the Outputs menu).
By default, the name associated to the measured acoustic transmission factor is Acoustic transmis. .
To add a user defined name to the default name, do the following:
→
Go to the CONFIGURATION view.
→
SAW sensor
→
Confirm to access the Parameter view.
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