Description of the difference between radar level gauge and ultrasonic level gauge

What is the difference between the radar level gauge and the ultrasonic level gauge? What are the two measurement principles? What are the operating conditions of the radar level gauge and the ultrasonic level gauge? The radar level gauge and the ultrasonic level What are the measurement accuracy? Let's talk about these two level gauges.
The radar level gauge uses a transmit-reflection-receive mode of operation. The antenna of the radar level gauge emits electromagnetic waves. These waves are reflected by the surface of the object to be measured and then received by the antenna. The time from the transmission to the reception of the electromagnetic wave is proportional to the distance from the liquid surface. The relationship is as follows:
D=CT/2
Where D is the distance from the radar level gauge to the liquid level
C——the speed of light
T——electromagnetic wave running time
The radar level gauge records the time elapsed by the pulse wave, and the electromagnetic wave transmission speed is constant, then the distance from the liquid surface to the radar antenna can be calculated to know the liquid level of the liquid surface.
In practice, there are two ways for radar level gauges, namely, frequency-modulated continuous wave and pulse wave. The liquid level meter adopting the frequency modulation continuous wave technology has large power consumption and must adopt a four-wire system, and the electronic circuit is complicated. The liquid level meter using radar pulse wave technology has low power consumption and can be powered by 24VDC of two-wire system, which is easy to achieve intrinsic safety, high precision and wide application range.
Ultrasonic waves are used for ultrasonic waves, and electromagnetic waves are used for radars. This is the biggest difference. Moreover, the penetration and directionality of ultrasonic waves are much stronger than those of electromagnetic waves, which is why ultrasonic detection is now more popular.
The difference between the main applications:
1. Ultrasonic accuracy is not as good as radar.
2. The relative price of the radar is higher.
   3. When using radar, consider the dielectric constant of the medium.
4. Ultrasonic waves should not be used in vacuum, steam content is too high or there is foam in the liquid surface.
5. The radar measurement range is much larger than the ultrasonic wave.
6. The radar has a horn type, a rod type, and a cable type, and the relative ultrasonic wave can be applied to more complicated working conditions.
We generally refer to sound waves with a sound wave frequency exceeding 20 kHz as ultrasonic waves. Ultrasonic waves are a kind of mechanical waves, that is, a kind of propagation process of mechanical vibration in an elastic medium. It is characterized by high frequency, short wavelength, and small diffraction phenomenon. It has good directionality and can be ray and directed to spread. Ultrasonic waves have little attenuation in liquids and solids, so they have strong penetrating power. Especially in solids that are opaque to light, ultrasonic waves can penetrate for several tens of meters. When they encounter impurities or interfaces, they will have significant reflection. Ultrasonic measurement The level is the use of this feature.
In the ultrasonic testing technology, no matter which kind of ultrasonic instrument, the electric energy conversion ultrasonic wave must be emitted, and then received and converted into an electric signal. The device for accomplishing this function is called an ultrasonic transducer, also called a probe. As shown in the figure, the ultrasonic transducer is placed above the liquid to be measured, and the ultrasonic wave is emitted downward. The ultrasonic wave passes through the air medium, is reflected back when it encounters the water surface, and is received by the transducer and converted into an electrical signal. When the electronic detection section detects this signal, it turns it into a liquid level signal for display and output.
It is known from the principle that the ultrasonic wave propagates in the medium. If the conditions of the medium pressure, temperature, density, humidity, etc. are constant, the propagation speed of the ultrasonic wave in the medium is a constant. Therefore, when the time required for the ultrasonic wave to be received until the liquid level reflection is received is measured, the path through which the ultrasonic wave passes can be converted, that is, the data of the liquid level is obtained.
The ultrasonic wave has a blind zone, and the distance between the sensor installation position and the measuring liquid must be calculated during installation.