Level is one of the important target parameters for industrial process monitoring. In the continuous level measurement of various tanks, silos, pools, etc., due to the wide variety of site conditions, it is difficult to have a level meter that can meet all working conditions. Among them, in the non-contact measuring instrument, the radar and ultrasonic two-level principle meter is widely used. So, what is the difference between the radar level gauge and the ultrasonic level gauge?

Ultrasonic level gauge

Generally speaking, sound waves with a sound wave frequency exceeding 20 kHz are called 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, small diffraction phenomenon, and other directions. Good sex, 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, regardless of the ultrasonic instrument, the electrical energy conversion ultrasonic wave must be emitted, and then received and converted into an electrical signal. The device that performs this function is called an ultrasonic transducer, also called a probe. During operation, the ultrasonic transducer is placed above the object to be tested, and the ultrasonic wave is emitted downward. The ultrasonic wave passes through the air medium, is reflected back when it encounters the surface of the object to be tested, 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 level signal for display and output.

Radar level gauge

The same as the ultrasonic level gauge, the radar level gauge also uses the transmit-reflection-receive mode of operation. The difference is that the radar level gauge is mainly dependent on the ultrasonic transducer, while the radar level gauge is based on the tuner. And antennas; ultrasonic level gauges use mechanical waves, while radar level gauges use ultra-high frequency (several G to tens of GHz) electromagnetic waves. The electromagnetic wave is operated at the speed of light, and the running time can be converted into a level signal by electronic components.

Another common radar level gauge is the guided wave radar level gauge. The guided wave radar level gauge is a radar level gauge based on the time domain reflection principle (TDR). The electromagnetic pulse of the radar level gauge propagates along the wire rope or probe at the speed of light. When encountering the surface of the measured medium, the radar Part of the pulse of the level gauge is reflected to form an echo and returns to the pulse transmitting device along the same path. The distance between the transmitting device and the surface of the measured medium is proportional to the propagation time of the pulse therebetween, and the liquid level is calculated.