是通过雷达技术的应用，来实现液位测量功能的一种新型的液位仪表。 Radar level gauge is a new type of liquid level instrument that realizes the function of liquid level measurement through the application of radar technology. The radar level gauge can achieve the purpose of judging the liquid level by transmitting extremely short microwave pulse signals with extremely low energy, and by receiving the reflected signals with the antenna system.
The radar wave emitted by the radar level gauge runs at the speed of light. After calculating the running time of the radar wave, the height position of the liquid surface can be obtained, that is, the radar wave signal is converted into a liquid level signal. The principle of the radar level gauge guarantees short measurement time, accurate results, and good stability during operation.
在工作环境较为复杂的状态下，也会存在虚假回波的问题，这就需要配合相应的微处理技术和调试软件，来对回波进行分析，确定回波的真实性，从而实际判断液位的高度数值。 The radar level gauge also has the problem of false echoes in a more complex working environment. This requires the corresponding microprocessing technology and debugging software to analyze the echoes and determine the authenticity of the echoes, thereby Actually judge the height value of the liquid level. Radar level gauge is a non-contact level gauge that can be used to measure various liquid media without being affected by physical factors such as density, concentration, temperature, etc. of the liquid medium, and can be used for some non-volatile corrosion Measurement of sexual media. At the same time, the radar level gauge has good adaptability to the temperature and pressure of the surrounding working environment and can be used for measurement in harsh environments such as high temperature and high pressure. The radar level gauge measurement is based on the action of radar waves, and the transmission of radar waves is not affected by the media, which can adapt to the measurement environment of dense fog and steam, and can be used for the measurement of volatile liquid media. The radar liquid level gauge is a liquid level instrument with an integrated design. There are no moving parts inside, no mechanical wear occurs during operation, and it has a long service life. The echo quality of the radar level gauge is mainly affected by the following factors: 1. The dielectric constant of the propagation medium, the more stable the constant, the better the propagation. Radar waves are electromagnetic waves, and electromagnetic waves are not affected by the stability of the propagation medium during the propagation process, and are only related to their dielectric constant. This is a major difference between radar technology and ultrasonic technology. 2. The surface condition of the measured medium. The flatter the surface and the larger the dielectric constant, the better it is for echo reflection. Therefore, when considering site conditions, special attention should be paid to these two aspects: 1. The distribution of the dielectric constant of the air between the antenna and the measured medium. 2. The surface state of the measured medium and its dielectric constant. The advantages of radar level gauges are that they are not affected by air fluctuations, have small attenuation with distance, and have strong penetrating power.
也存在一定的局限性；其一，影响雷达物位计的性能是介电常数，在真空中雷达衰减极小，当空气中存在影响雷达衰减的物质时，例如：含高介电性的粉尘粉末（石墨，铁合金等），水蒸气等，其测量距离和效果都会受到影响。 At the same time, the radar level meter also has certain limitations. First, the performance of the radar level meter is affected by the dielectric constant, and the radar attenuation in the vacuum is extremely small. Dielectric dust powder (graphite, iron alloy, etc.), water vapor, etc., will affect the measurement distance and effect. Second, if the volatile gas of the measured medium accumulates on the antenna, or water vapor condenses on the antenna, at this time, it will affect the radar wave emission, which may cause the radar wave to fail to emit. Third, the dielectric constant of the measured medium cannot be too small. Fourth, although the temperature and pressure have very little effect on the radar, because the radar antenna is made of different materials, the range in which the radar level gauge can adapt to temperature and pressure depends on the materials used by the antenna and the level gauge itself. Sealed structure.
In the application of ultrasonic level gauges, to obtain better echoes, the operating frequency of the transducer is about 40KHz and the wavelength is about 9mm. At this time, the opening angle of the transmitted wave is 7 ° -8 °. The higher the operating frequency, the smaller the opening angle, and the smaller the range. Compared with ultrasonic level gauges, to obtain the above-mentioned effects of radar level gauges, the operating frequency should be 26GHz, at this time, its wavelength is 11mm. When using a horn with a diameter of 100mm, a 7 ° -8 ° open wave can be obtained. If the operating level of the radar level gauge is 6GHz, it is equivalent to the operating frequency of ultrasonic waves being 10KHz. The ultrasonic level meter with a working frequency of 10kHz is not ideal in level measurement, and is not suitable for solid level measurement.