Silo Radar Level Measurement refers to the use of high-frequency radar level meters for continuous level measurement of solids or powders. High frequency radar level meter is currently the mainstream product for measuring solid level in the world. It can measure cement silo, grain silo/bin, truck loading, raw coal, ore, high-density polyethylene powder silo, etc.
Next, let’s analyze why we prefer to choose radar level meters to measure silo levels.
Difficulties in Measuring Powder and Granular Silos
Measurement difficulty 1:
The silo is slender and the space is narrow. The measurement signal is easy to hit the silo wall.
If there are obstacles such as ring beams on the warehouse wall, or material hangs on the warehouse wall due to the humidity of the material. False signals will be generated, which will seriously affect the measurement.
At the same time, due to the narrow space, the measurement signal cannot avoid the material flow. Which will also cause a significant attenuation of the signal.
Measurement difficulty 2:
The dust is large. It will cause great loss to the signal.
As a result, the material level signal is greatly reduced, and even no signal can be recovered.
Measurement difficulty 3:
Adhesion to meter antenna.
For wet materials, the powder is easy to form serious adhesion on the antenna of the radar level gauge;
For dry materials, due to the collision and friction between the particles, the powder is prone to static electricity. This will accelerate the adsorption of the powder on the antenna. And will also cause serious adhesion problems.
Measurement difficulty 4:
The general powder dielectric constant is very low.
For example, fly ash, lime powder, and pulverized coal in power plants. Plastic powder, plastic granules, and catalyst particles in petrochemical plants. In addition, there are alumina powder, silica powder, cement, wood chips, etc. The dielectric constant is very low. For radar As far as the instrument is concerned, it will cause the instability of the material level signal. Even the material level signal cannot be received.
At present, the detection method of silo material level mainly relies on ultrasonic level gauge, radar level gauge, laser range finder and so on.
Some detection methods can only be used as an alarm signal. That is, the material is lower than the material level to replenish the material in time, and the material level is higher than the material level to stop filling.
Some methods are limited by technical principles and have strict requirements on installation conditions.
Some methods are limited by measuring height, making them expensive.
So, why is the radar level meter so popular?
Silo Radar Level Measurement-Cement
Material level is one of the main measurement parameters of cement production enterprises. Compared with other production enterprises, cement enterprises measure less liquid level. It is mainly the measurement of the height of solid matter in the production process.
Solid materials are lumpy, granular, and powdery. These materials also vary in dielectric constant, bulk density, temperature range, and moisture content.
The main raw materials for cement production are: limestone, clay (shale, sandstone), iron powder (iron ore, iron slag), coal gangue, industrial waste residue, raw coal, gypsum, slag, fly ash.
The above raw materials enter their respective silos after drying and crushing. At this time, high-frequency Radar Level Meters can be used to monitor the material level.
Contact level measurement is the main measurement method of cement production enterprises in the past. Such as capacitive type, weight level gauge, tuning fork, and other measurement methods. During the contact process of measuring things, measuring instruments and materials, they often face a large number of Routine maintenance. Such as the problem of capacitor material hooking.
By the end of the 20th century, the cement industry started using non-contact level measurement.
The following points should be paid special attention to when cement production enterprises choose Radar Level Meters:
- Pulse and FMCW radar
Generally divided into two categories: pulsed (impulse) radars and frequency modulated continuous wave (FMCW) radars are used to measure radar levels with level gauges.
Large measurement range and high reliability due to radar transmission power. This is the reason why Radar Level Meters are widely used in the cement industry recently.
- Selection of granular materials
The raw materials of cement are mostly in granular matter, and some are block materials. Such as limestone, coal, oil shale. It is recommended to use non-contact Radar Level Meters, horn antenna Radar Level Meters.
- Selection of powdery materials
The materials in the cement and cement grinding warehouses are the cement raw materials. The powder of these materials is difficult to predict the substance level. The surface of the powder is very loose, which is very difficult for microwave reflection. It is recommended to use contact Radar Level Meters, or non-contact radar level gauges with horn antennas. This is a typical radar application in China.
Most of the current Radar Level Meters are integrated and powered by wires. It can be directly connected to the control system module and output 4~20mA analog signals. It can save a lot of cables. It also provides a variety of HART digital signals. Protocol and fieldbus digital communication .The connection of the computer monitoring system is very convenient.
It should be noted that guided wave radar should be used with caution in powder measurement in cement plants. This is because most cement plant drying equipment is not ideal. There is often moisture or even steam. Once condensation will cause various powders to condense on the Caused a fault on the waveguide cable.
In addition, depending on the range, for powdery materials such as fly ash, slag powder, cement products, etc., parabolic antenna radar can also be used.
The level measurement of cement plays a very important role in the automation system of the cement production line. The application of Radar Level Meters can relieve the variety, accuracy, standard substance, pressure, high temperature, explosion. It greatly facilitates the cement production enterprises in the level parameters Accurate measurement on the surface. The existing Radar Level Meters technical level and on-site use are sufficient to meet the requirements of detection and control.
Silo Radar Level Measurement – Grain Silo
There are many kinds of media in the granary, and rice is a kind of grain. Then it is ok to want to use Radar Level Meters to measure the rice in the granary. Radar Level Meters can not only measure the rice in the granary, but also measure various media in the coal bunker.
Radar Level Meters can choose the conventional 26GHz/80GHz planar radar level meter to measure the rice in the granary. The measurement range selected by the selection is a distance of 70m. Debugging mode is with LCD display type. The power supply is 24V. Output signal selection 4-20mA. Can also bring HART protocol.
Silo Radar Level Measurement-Raw Coal
The fuel bunker is usually a raw coal bunker or a pulverized coal bunker, and the medium of the raw coal bunker is raw coal with larger particles and less dust than the pulverized coal bunker. Radar Level Meters are suitable for this situation.
The pulverized coal particles in the pulverized coal bin are small and have a lot of dust. If the proportion of pulverized coal exceeds 70%. In addition, the measurement environment of pulverized coal material level is harsh and the coal quality is unstable. Due to the influence of factors such as the position of the material port, it is more appropriate to use a radar level gauge with stronger anti-interference ability.
The common forms of Radar Level Meters are bell mouth type, parabolic type and rod type. The difference in structure is mainly due to the difference in transmission frequency, beam angle and measurement range. The measurement distance of the fuel tank is not very long, so the commonly used bell mouth radar level gauge is the best choice.
Because of the high reliability, stability and accuracy of Radar Level Meters, it is widely used in fuel tank level measurement. However, in order to obtain accurate material level measurement values, special attention should be paid to the installation of Radar Level Meters to avoid radar echoes being interfered by interference sources.
Here are a few installation tips for Radar Level Meters to measure fuel tanks:
The selection of the installation position needs to be based on the form of the fuel tank, and the top-mounted form is adopted;
In addition, keep a certain distance from the wall of the fuel tank to reduce the reflection and interference of the tank wall;
It is also necessary to keep a certain distance from the discharge port of the fuel bin to reduce the interference of fuel and dust at the discharge port.
Silo Radar Level Measurement-HDPE Pellet Silo
The high-density polyethylene powder silo has a slender body, large dust, and low dielectric constant of the medium; it poses a great challenge to the level measurement.
Aiming at the characteristics and complexity of large powder silo measurement, Sino-Inst’s radar level gauge has a range of up to 120m. Due to its high focus, strong signal, high dust resistance and other characteristics. It can well solve the above measurement difficulties and achieve stable and accurate measurement.
Featured Radar level meters for Silo
- Measuring medium: solid
- Measuring range: 0.3m~150m
- Process connection: flange≥DN80
- Process temperature: -40～110℃
- Process pressure: -0.1～0.3MPa
- Antenna size: 78mm lens antenna + purging (or without purging)
- Antenna material: PTFE
- FMCW radar operating at 76-81 GHz;
- Maximum measuring range of 120m and a minimum blind zone of 8cm;
- 3°antenna beam angle;
- Suitable for small water tanks or small process accessories in narrow spaces.
- Good signal focusing ability can be used for containers with many internal installations.
- Measurement accuracy:±1mm
- Installation method: Thread or flange, clamps are optional.
- Anti-dust, anti-steam condensation
- Application: solid materials, strong dust, easy to crystallize, condensation occasions
- Measuring range: 70 meters
- Process connection: universal flange
- Process temperature: -40～130℃ (standard type) / -40～250℃ (high temperature type)
- Process pressure: -0.1～4.0 MPa (flat flange) -0.1～0.3 MPa (universal flange)
- Accuracy: ±15mm
- Protection level: IP67
- Applicable medium: solid particles or blocks, not suitable for solid powder
- Application: Lime block measurement; raw coal measurement
- Explosion-proof certification: Exia IIC T6 Ga/ Exd IIC T6 Gb
- Measuring range: 35m
- Antenna: Horn antenna
- Frequency: 6 GHz
- Process temperature: -40～130℃(standard type)/-40～250℃(high temperature type)
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The powder silo is an application that is difficult to use continuous level measurement in solid level measurement. Especially for large, slender powder silos. Greater challenges are posed to measuring instruments.
Currently on the market, there are mainly capacitance, ultrasonic level gauges, guided wave radar level gauges and high-frequency radar level gauges that can be used to measure powder silos.
Each measurement method has its own advantages and disadvantages. But all in all, Silo Radar Level Measurement is the most successful and widely used.
Especially high-frequency radar level gauges with small emission angles. Thanks to the rapid development of high-frequency radar technology.
It has continuously overcome insurmountable obstacles such as large range, narrow space, high dust, and low dielectric constant in the past. It has achieved great success in the continuous level measurement application of Silo Radar Level Measurement.
If you have any questions about Silo Radar Level Measurement, . Or you need Silo Radar Level Measurement technical support, please feel free to contact our sales engineers.
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