Ultrasonic level gauge or radar level gauge? How to select liquid level gauge

In recent years, ultrasonic technology has developed rapidly. As a non-contact measurement method, it is widely used in the field of liquid level measurement. The ultrasonic liquid level gauge adopts the ultrasonic technology. Ultrasonic belongs to mechanical wave, which is characterized by high frequency, short wavelength, small diffraction phenomenon and good directivity. It can become a ray and propagate directionally. The attenuation of ultrasonic wave in liquid and solid is very small, so it has strong penetration ability. Once it touches obstacles or liquid surface, it will have significant reflection.

Unlike the ultrasonic level gauge, the radar level gauge is an electromagnetic wave with strong penetration. Its propagation speed is not affected by dust, steam and medium components, and the propagation attenuation is very small; The temperature, pressure and density of the medium hardly affect the accurate measurement; In addition, the on-site debugging is also very simple. Through the special software, the correct echo can be quickly found and immediately converted to the level value.

Because the working mode, working principle and characteristics of radar level gauge and ultrasonic level gauge are very different, their application fields are also different. The specific differences are as follows: the measuring range of the radar level gauge is larger than that of the ultrasonic level gauge, so the radar level gauge can be used to measure the level in large storage tanks, tower tanks and water tanks with high height.

Although the ultrasonic liquid level gauge can also be used to measure the solid level in some specific cases, for the solid or powder materials with low dielectric constant and dust, such as pulverized coal silo and ash silo, the ultrasonic wave of the transducer will cause great loss. Therefore, the ultrasonic liquid level gauge is generally not selected under this working condition. It is recommended to select the high-frequency radar liquid level gauge and select such large-size wavelet beam antenna as parabolic antenna.

Because the radar liquid level gauge adopts electromagnetic wave, it does not need propagation medium and can be applied in vacuum environment. On the contrary, the mechanical wave of the ultrasonic level gauge needs a propagation medium, so it can not be used in the vacuum environment. For example, guided wave radar level gauge can be used to measure the water level of condenser hot well, but ultrasonic level gauge is not applicable.

Guided wave radar level gauge is an ideal choice for liquid level measurement of storage tanks where liquid ammonia, concentrated hydrochloric acid and other volatile or diffusing vapors are likely to form, or when the liquid level may produce foam. However, it should be noted that if the storage tank is small in size, it is recommended to use high-frequency radar level gauge under this working condition.

The accuracy of ultrasonic liquid level gauge is lower than that of radar liquid level gauge. However, in terms of cost performance, the electronic circuit of radar liquid level gauge producing high-frequency electromagnetic wave is relatively complex, which makes the product price higher. Therefore, the cost performance of ultrasonic liquid level gauge is higher than that of radar liquid level gauge. When the accuracy requirement is not particularly high or the measured liquid level is ideal, the ultrasonic liquid level gauge can be applied well while saving cost.

Ultrasonic liquid level gauge is a non-contact, highly reliable, cost-effective and easy to install and maintain level measuring instrument. It is a device that can transmit energy wave (usually pulse signal). The energy wave is reflected by obstacles, and a receiving device receives the reflected signal. The change of material level is determined by measuring the time difference of energy wave movement process. The microwave signal is processed by the electronic device and finally transformed into the electrical signal related to the material level.

The ultrasonic liquid level gauge consists of three parts: ultrasonic transducer, processing unit and output unit.

Under complex working conditions, more than one ultrasonic liquid level gauge is installed to measure the liquid level from time to time. For example, when measuring some liquid storage tanks with large capacity, the measurement range of one ultrasonic level gauge may not be enough to cover the whole liquid level, resulting in some blind areas. At this time, two ultrasonic level gauges need to be installed to achieve the best measurement effect.

Both radar and ultrasonic liquid level meters are good solutions for industrial level measurement. Their application fields should be determined according to process conditions, medium characteristics, installation conditions, service environment and other external factors.

Post time: 16-06-22