Radar level meter is a measuring instrument in the radar level gauge that can be used to measure the level of liquid in a container. Radar level gauges are precision instruments that are slightly higher in price than other types of measuring instruments. In order to make the selected radar level gauge better match the application conditions, it is quite necessary to select the correct type according to the field conditions. Based on the above considerations, the selection points of the radar level gauge are summarized, and it is hoped that the correct selection of the users can be helpful, so that the radar level gauge can be better applied.
In general, the selection of radar level gauges has the following main points:
1. The dielectric constant of the measured medium directly affects the transmission quality of the radar wave. If the dielectric constant of the medium is larger, the reflection effect is more obvious, and the measurement is more favorable. A radar level gauge is not recommended for media with a dielectric constant below 1.4. A guided wave radar level gauge is recommended for low dielectric constant media. For example, EO ethylene oxide has a dielectric constant of 14 at normal temperature, which is relatively low. It is recommended to use a guided wave radar level gauge or prefabricated waveguide in the equipment.
2. For the measurement of liquid levels such as crude oil, refined oil, asphalt, ethylene, propylene, liquefied petroleum gas, and liquefied natural gas in large vault tanks and spherical tanks, it is recommended to use an antenna radar level gauge; Guided wave radar level gauges are recommended for tank, outer floating roof tanks, pressure tanks, level measurement with agitator or swirling process tanks.
3. According to the measurement accuracy, the radar level gauge can be divided into control level and metering level. The accuracy of the control level should not be lower than ±0.5%, and the accuracy of the metering level should not be lower than ±3mm.
4. The radar level gauge installed on the tank in the tank area is recommended to have a tank side indicator to make it easier to monitor.
5. The power supply form of the radar level gauge has two-wire system and four-wire system. The general control level uses two-wire system, and the high-precision metering level can be used in four-wire system. In general, the radar level gauge is preferred to supply 24V DC. If the installation location is far from the instrument cabinet, 220V AC should be used. 6. The antenna type radar level gauge should select the appropriate antenna type according to the actual working conditions. The most commonly used is the bell antenna. This type of antenna has good convergence characteristics, but it is not suitable for the measurement of corrosive media. If the pressure of the container is too high, it is easy to cause leakage and should be carefully selected. High-voltage equipment or corrosive medium It is recommended to use a flat-sealed antenna; the rod antenna is small in size and suitable for installation where the installation conditions are limited. The antenna material is variously selected and suitable for corrosive media. The parabolic antenna is not affected by heating steam and is suitable for large-scale heating steam. Containers, such as residual oil tanks, asphalt tanks, etc.