是一种微波物位计，它是微波（雷达）定位技术的一种运用。 Radar level gauge is a microwave level gauge, which is an application of microwave (radar) positioning technology. It transmits energy waves through a device that can transmit energy waves (generally pulse signals). The energy waves are transmitted in the waveguide. The energy waves are reflected by obstacles. The reflected energy waves are transmitted by the waveguide to the receiving device. The receiving device receives the reflected signal. The change in level is determined according to the time difference of the measured energy wave motion process. Microwave signal is processed by the electronic device, into electrical signals associated with the final position thereof. For level and volume monitoring of tank liquids, slurries or liquids and slurries in process vessels. The radar level meter consists of a processor and a signal that is sent out and receives signals reflected from the surface of the material. The processor identifies the correct echo signal through intelligent software, and uses the equivalent sampling method to accurately obtain the time difference between the signal transmission and reception. The time period from when the radar signal is transmitted to when it is received is proportional to the distance, that is, the level. The calculation accuracy can reach millimeter level.
是通过天线系统以及拥有一个信号持续1ns， 信号周期278ns 的信号包发射。 The radar level gauge is transmitted through the antenna system and a signal packet with a signal for 1ns and a signal period of 278ns. It also matches a packet frequency of 3.6MHz. In the signal period, the antenna system operates as a receiver. The signal operation period must be less than one billionth of a second. The echo image must be processed within one second. The material level is in the industrial production process. One of the most important parameters for measurement is the non-contact measurement method which has been the main method for measuring material levels in recent years. The more mature non-contact measurement technologies include ultrasonic technology and nuclear radiation technology. Nuclear radiation level meters have radiation zenith, The application requires special approval, so it is only used in situations that cannot be solved by other methods, and the application is limited. Ultrasonic technology has developed rapidly in recent years, and the price of electricity has decreased. It is currently the most widely used non-contact measurement method. However, ultrasonic waves must be transmitted by means of media. Air is usually used as the propagation medium in the level-side measurement. Changes in depression, humidity, composition, etc. will affect the ultrasonic propagation speed, so compensation needs to be performed when measuring.
).微波的传播则不受上述因素影响.特别是在化工、石化等过程工业领域，由于被侧物位介质普退存在高沮、高压、腐蚀、挥发、冷凝等复杂工况，而且有防爆要求，故比起超声波物位计，它更有优势.近年来超高频半导体器件技术的发展，低价、高性能的徽波物位计(雷达物位计)的推出，使其能以较低的价格用于过程检测。 In 1998, a high-performance, low-cost emblem level meter ( radar level meter ) appeared in the field of process detection. The propagation of microwaves is not affected by the above factors. Especially in the process industry fields such as chemical industry and petrochemical industry, because The side-level medium has a complex condition such as high pressure, high pressure, corrosion, volatilization, and condensation, and has explosion-proof requirements. Therefore, it has more advantages than ultrasonic level meters. In recent years, the development of ultra-high-frequency semiconductor device technology The introduction of low-cost, high-performance Huibo level gauges (radar level gauges) enables them to be used for process detection at a lower price. For large storage tanks, radar level gauges are suitable for liquid level measurement of easily condensable, suspended liquid, cat thick and corrosive liquids. Its characteristics are: no displacement, no transmission parts, non-contact measurement ， It is not limited by temperature, pressure, steam, aerosol and dust; At the same time, the radar level gauge has no measurement blind zone, the error of the liquid level measurement is only 0.1 to 1. 0mm, and the resolution is 1 ~ 20mm. Industrial measurement can also be used for metering. The natural radiation frequencies emitted by various objects spread throughout the entire electromagnetic spectrum, usually at wavelengths. 0.001 ~ lm, electromagnetic waves in the frequency range from 30OMHz ^ -3000GHz are called microwaves. Microwaves have the characteristics of electromagnetic waves and are different from ordinary radio waves and light waves. Their characteristics are as follows.
① Directional propagation. Using this feature, microwaves can be directionally transmitted to space through directional antennas, and ② quasi-optical characteristics. It has characteristics similar to light waves. That is, when entering from one medium to another, refraction and reflection will occur. The better the dielectric conductivity or the larger the dielectric, the better the reflection effect of the echo signal. When it encounters a plane, total reflection occurs, and its diffraction ability is poor. ③ Good communication characteristics. The propagation speed is equivalent to the speed of light. It can penetrate through clouds, fog, and light rain, and is less affected by dust, smoke, and strong light. It is very favorable for environmental remote sensing and military applications. ④ The microwave absorption of the medium is proportional to the dielectric constant, and the absorption of water by microwave is the strongest.