An ultrasonic level meter is a non-contact, low-cost, level meter for continuous measurement of liquid level. Although the installation is simple, if the installation process is not installed properly, the normal measurement of the ultrasonic level meter will also have a great impact.
According to the working principle of the ultrasonic level meter, the ultrasonic level meter detects the liquid level height by transmitting ultrasonic waves and its reflected echo signal, so when installing the ultrasonic level meter, the transducer (probe) of the ultrasonic level meter should be installed perpendicular to the measured liquid surface and make sure that it is solid without tilting and displacement.
According to the different shapes of the container roof, ultrasonic level meter installation location selection should try to avoid the liquid surface and the roof wall to produce multiple reflections between the echo,to reduce interference, reduce the noise signal, to ensure the accuracy of detection.
Ⅰ Ultrasonic level meter installation should pay attention to several points:
The ultrasonic level meter reasonable installation location should be determined according to the different topsof the liquid container and the shape of the internal structure:
A. Trench type container:
( 1 ) The support frame should be firm and reliable;
( 2 ) The height of the intersection line between the beam emitted by the probe and the groove wall must be less than or equal to the minimum height of the measured liquid level;
( 3 ) The installation height should be ensure do be within the required range.
B. Vaulted Vessels:
The meter can not be installed in the vaulted irrigation top, it should be installed at 1/2 or 1/3 of the radius of the irrigation top.
C. Conical vessels:
For conical containers and for the flat top of the container, the best installation location for the meter is the top of the container in the center, so that the measurement can be guaranteed to the bottom of the container.
The ultrasonic level meter in the installation should pay attention to the “blind zone” problem.
Different ranges of ultrasonic level meters, corresponding to the “blind zone” size are not the same. Due to the liquid level in the blind zone, the ultrasonic level meter can not be accurately measured. Therefore, in the selection to determine the range of the ultrasonic level meter, must be reserved for more than or equal to the “blind zone” size margin. That is, the probe height and the height of the highest level of the difference between the height must be greater than or equal to the “blind zone” size to ensure accurate monitoring of the liquid level, and to ensure the safety of the instrument (to avoid probe submerged by the liquid).
An ultrasonic level meter should be installed to avoid obstacles.
As the ultrasonic level meter transducer (probe) issued by the pulse sound waves has a certain launch angle, which requires the installation of an ultrasonic level meter, from the lower edge of the probe to the surface of the liquid to be measured between, in the region of the emitted beam radiated by the obstacles shall not be (including the vessel wall). Therefore, in the installation of an ultrasonic level meter, one should avoid such obstacles as human ladders, limit switches, heating equipment, brackets, and other obstacles. At the same time, it must be noted that the ultrasonic level meter emitted beam shall not be intersected with the feeding material flow.
Ultrasonic level meter installation should pay attention to the pressure and the surrounding environment.
The ultrasonic level meter is generally applicable to the atmospheric pressure environment, pressure or negative pressure on the acoustic wave propagation speed has an impact on the measurement accuracy, serious overpressure or negative pressure will even lead to the ultrasonic level meter can not work properly.
When the ultrasonic level meter is used in an outdoor or humid environment, you need to pay attention to the cable access along the leadway. The correct method is to bend the cable and lead it downward to prevent water or moisture from entering the meter (D Moisture-proof Installation Schematic). Also, for safety reasons, wiring or disconnecting cables must be done in the event of a power failure.
When installing the ultrasonic level meter in an explosion-proof area, the installation regulations of the national explosion-proof hazardous area must also be observed.
Ultrasonic level meter installation should pay attention to whether the instrument model meets the environmental requirements of the site.
Finally, it should be reminded that, before installing the ultrasonic level meter, one must confirm whether the instrument model meets the process pressure, process temperature, chemical properties of the medium，and other environmental requirements of the site, to ensure that the instrument can be used normally after installation.
Ⅱ. Ultrasonic level meter installation principles.
- The distance from the transducer of the ultrasonic level meter to the lowest liquid level should be less than the range of the optional instrument.
- The distance from the transducer transmitting surface to the highest liquid level of the ultrasonic level meter should be greater than the blind zone of the optional instrument.
- The transmitting surface of the ultrasonic level meter should be parallel to the liquid surface.
- Ultrasonic level meter transducer installation location should try to avoid directly below the inlet, outlet , and another liquid level with violent fluctuations in the location.
- If the pool wall or tank wall is not smooth, the ultrasonic level meter needs to leave the pool wall or tank wall more than 0.5m.
- If the distance from the transducer of the ultrasonic level meter to the highest liquid level is less than the blind zone of the optional instrument, it is necessary to install an extension tube, the extension tube needs to be perpendicular to the liquid level, and the inner wall should be kept smooth.
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