Radar level gauge
Principle: Transmitting-reflection-receiving is the basic working principle of radar level gauge.
The antenna of the radar sensor transmits electromagnetic wave signals in the form of a beam. The transmitted waves reflect on the surface of the measured material, and the reflected echo signals are still received by the antenna.
Each point of the emitted and reflected beam is collected by ultrasonic sampling. The signal is processed by the intelligent processor and the distance between the medium and the probe is sent to the terminal display, alarm, operation and so on.
Features: The biggest feature of radar level gauge is that it is effective under severe conditions. Whether it is toxic medium, or corrosive medium, whether it is solid, liquid or dust, slurry medium, it can be measured. In terms of measurement, it has the following characteristics:
1, continuous and accurate measurement
The probe of radar level gauge has no contact with the surface of the medium. It is a non-contact measurement, which can accurately and quickly measure different media. The probe is almost unaffected by temperature, pressure, gas, etc. (only 0.018% at 500℃, 0.8% at 50bar).
2. It has the function of suppressing interference echo
3, accurate, safe and energy saving
The chemical and mechanical properties of the radar level gauge are quite stable, and the material can be recycled, which has the effect of environmental protection.
4, no maintenance and strong reliability
Microwave is almost free from interference, no direct contact with the measuring medium, almost can be used in a variety of occasions, such as vacuum measurement, liquid level measurement or material level measurement. Due to the use of advanced materials, extremely complex chemical and physical conditions are very durable, it can provide accurate and reliable, long-term stability of analog or digital level signal.
5, easy maintenance, simple operation
Radar level gauge has fault alarm and self - diagnosis function. Analyze the fault according to the error code prompted by the operation display module, determine the fault and remove it in time, make the maintenance and correction more convenient and accurate, and ensure the normal operation of the instrument.
6, a wide range of application, almost can be measured all media
From the shape of the tank, the radar level gauge can measure the liquid level of the spherical tank, horizontal tank, cylindrical tank, cylindrical vertebral tank, etc. From the function of the tank, it can measure the liquid level in the storage tank, buffer tank, microwave tube and bypass pipe. From the measured medium, the liquid, particles, slurry and so on can be measured.
Summary:
In general, the radar level gauge is a wide range of non-contact measurement. Excellent material, low failure rate.
Guided wave radar level gauge
Principle: Guided wave radar level gauge is a measuring instrument based on the time-travel principle. Radar wave runs at the speed of light, and the running time can be converted into level signals through electronic components. The probe sends out a high-frequency pulse and travels along the cable probe. When the pulse hits the material surface, it is reflected back and received by the receiver in the meter, converting the distance signal into a level signal.
The characteristics of
1, has a strong ability to inhibit steam and foam, measurement is not affected;
2, not affected by liquid density, solid material degree of porosity, temperature, dust when feeding;
3, low maintenance, high performance, high precision, high reliability, long service life.
Is there a difference?
The contact mode is different: radar level meter is non-contact, waveguide level meter is contact. That is to say, in the food grade requirements of higher occasions, is not to use the pilot type.
The operating condition of the medium is different: guided wave radar level gauge more need to consider the corrosion and adhesion of the medium, and too long guided wave radar installation and maintenance is more difficult. The operation condition of the low dielectric constant, regardless of the radar or guided wave radar measurement principle is based on the dielectric permittivity difference, due to the launch of ordinary radar wave is divergent, when the dielectric constant of the medium is too low, the signal is too weak to measure is not stable, and is guided wave radar wave propagation along the wave guide rod signal is relatively stable, generally at the bottom of the guided wave radar and other detection function, According to the bottom echo signal can be modified to make the signal more stable and accurate.
The selection is different: ordinary radars can be used interchangeably, but guided wave radars cannot be used interchangeably because the length of guide rod (cable) is fixed according to the original working condition. Therefore, the selection of guided wave radars is more troublesome than that of ordinary radars.
The measuring range is different: common radar is commonly used in 30 and 40m tanks, and even 60m can be measured. Guided wave radar also needs to consider the stress of the wave guide rod (cable). It is also because of the stress that the measuring distance of guided wave radar is generally not very long.
However, in some special conditions the guided wave radar has obvious advantages, such as stirring in the tank, medium fluctuation, such conditions with the bottom fixed guided wave radar measurement value is more stable than the flexible radar; There is also the level measurement in the small tank. Due to the small installation and measurement space (or more interferors in the tank), the ordinary radar is generally not applicable. At this time, the advantages of guided wave radar appear.
