Radar liquid level meter and ultrasonic meter where is the difference? The measuring principle of both what? Radar liquid level meter and ultrasonic liquid level meter used in the kind of condition? Radar level meter and ultrasonic level measurement accuracy is? We have these issues and explain this two level gauge.
Radar level gauge with emission-reflection-receive mode. Radar level meter antenna emits electromagnetic waves, these waves are reflected on the surface of the object to be measured, antennas, electromagnetic waves from the transmitter to receiver is proportional to the distance to the surface, relations are as follows:
D--radar level gauge the distance to the surface
C—— the speed of light
T--electromagnetic wave running time
Pulse Radar level gauge records the elapsed time, and speed of an electromagnetic wave is a constant, you can calculate the surface distance to the radar antenna, so as to know the level of liquid.
In the practical application of radar level gauge has two frequency modulated-continuous wave and pulsed wave. Of liquid level meter using frequency modulated continuous wave technique, high power consumption, using four-wire, complex electronic circuits. Radar pulse wave technology of liquid level meter is used, low power consumption, the 24VDC power supply of two-wire available, easy to achieve intrinsic safety, high accuracy, more widely applicable.
Ultrasonic sound waves, radar by electromagnetic waves, which is the biggest difference. And ultrasonic penetration and direction are much stronger than the electromagnetic, ultrasonic detection is now more popular causes.
Main difference between applications:
1. ultrasonic precision than radar.
2. relatively higher price.
3. radar is used when considering the permittivity of the medium.
4. ultrasonic vacuum, steam cannot be applied to high levels or conditions such as liquid bubbles.
5. radar scope is much larger than the ultrasound.
6. a horn style, Rod, cable, ultrasound can be used for more complex conditions.
We over 20kHz sound frequency sound waves called ultrasound, ultrasonic wave is a mechanical wave, which is a kind of mechanical vibrations in elastic media propagation, which is characterized by high frequency, small wave length diffraction phenomena, good direction, can become the ray directed dispersal. Ultrasonic attenuation in the liquid and solid is very small, thus penetrating ability, especially in light in opaque solids, ultrasound through dozens of meters length, having impurities or interface will have a significant reflection of ultrasonic level measurement is the use of its features.
In ultrasonic testing, regardless of the kind of ultrasonic instrument, must convert the ultrasonic power emitted and received back into an electrical signal, complete the installation of this feature is called an ultrasonic transducer, also known as a probe. As shown in the figure, the ultrasonic transducer placed above the liquid to be measured, down-firing ultrasonic, ultrasonic wave through the air, in the face of the water is reflected back, and are received by the transducer and converted to electrical signals, electronic detection part detects the signal and turn it into liquid level display and output signal.
The principle of ultrasonic propagation in media, if the medium conditions such as pressure, temperature, density, humidity, ultrasonic wave propagation velocity is a constant in the medium. Thus, when measured by emission to meet the surface reflection is the time required to receive, you can convert the ultrasonic passed away, that is the level of data.
Ultrasonic blind spots, reserve must be calculated when installing sensor installation locations and measuring the distance between them.