Analysis of various interference factors in radar level gauges
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A radar level gauge works by emitting electromagnetic waves toward the medium being measured; these waves are reflected back when they encounter the medium. By utilizing the principle of time dilation, the time interval between the emission and reception of the electromagnetic waves is determined, which in turn allows for the calculation of the distance from the antenna to the surface of the medium being measured. It is evident that whether a radar level gauge can transmit electrical signals successfully is crucial for level measurement. However, in our daily work, signal interference occurs from time to time. So, what are the interfering factors that cause abnormal signals in radar level gauges? An analysis of the factors causing signal abnormalities in radar level gauges reveals that there are many causes of interference, and the sources of interference are also diverse. But generally, they can be divided into two categories: internal interference and external interference. 1. Celestial bodies and radio interference from celestial bodies refer to the Sun or other stars. Therefore, interference from celestial bodies means that the electromagnetic waves emitted by them cause certain interference with the signals sent out by radar level gauges. However, the term “sky electricity” is generally unfamiliar to everyone. In fact, what is known as atmospheric noise can be understood as interference caused by electromagnetic waves generated from ionization processes such as those involving the atmosphere and lightning, or from natural phenomena like volcanoes and earthquakes, which affect the signals of radar level gauges. 2. Optical interference: The interference caused by light mainly affects semiconductor components. Among the components used to control instruments, many are made of semiconductor materials. When these semiconductor elements are exposed to light, their electrical conductivity changes, which in turn affects the proper operation of radar level gauges. 3. Thermal interference: During the operation of thermal power plants, their thermal equipment generates a large amount of heat, and this heat can cause changes in the temperature of surrounding instruments and the environment – this is what is referred to as thermal interference. These interferences can affect the components of radar level gauges, subsequently leading to issues such as inaccurate measurements. 4. Humidity interference: As humidity increases, it leads to a decrease in the resistance of insulators, an increase in the dielectric constant of dielectrics, swelling of the framework, and an increase in resistance. This in turn results in an increase in leakage current, an increase in capacitance, and changes in inductance. Additionally, it softens the gel, and the measurement precision also decreases. 5. Mechanical interferenceMechanical interference refers to situations where significant vibrations or shocks from external machinery affect the radar level gauge. This can cause certain components inside the gauge to vibrate, shift, or even deform. It may also loosen the pointer on the instrument’s display, leading to measurement errors. To mitigate such effects, we typically use partitions, shock-absorbing springs, and similar measures to reduce the impact. German Medisight would like to remind all users that although interference is omnipresent, manufacturing units generally carry out numerous experiments and optimize circuit programs in order to eliminate such interference.
I’ve learned about it, but I’m not sure whether radar level gauges are suitable for reactors that have mixing blades
Generally, liquids that contain water are polar materials; if such a liquid adheres to the sensor and reaches a certain threshold, electromagnetic waves cannot be emitted nor retrieved. For some mixing conditions, installing an 80G or 120G radar can solve the problem of level measurement, but there are also many conditions for which it is not suitable.
Learned it! The same question applies to the second floor.
For HKRD radar level gauges, there are many causes and sources of interference. We analyze from four aspects: internal, external, AC, and DC. I. External Interferences 1. Celestial and ionospheric interference. First, what is celestial interference? Celestial bodies refer to the Sun or other stars; therefore, celestial interference refers to the interference caused by their electromagnetic waves on radar level gauges. We are quite unfamiliar with atmospheric electricity. By “atmospheric electricity,” we generally mean the interference caused by electromagnetic waves—generated through ionization processes involving the atmosphere, lightning, or natural phenomena such as volcanoes and earthquakes—to the signals of radar level gauges. 2. Mechanical interference: By mechanical interference, we mean that certain components inside the radar level gauge can also vibrate, or even shift and deform, due to extensive vibrations or impacts from external machinery. This can also cause the pointer on the instrument’s display to become loose, resulting in measurement errors. In such cases, we usually use baffles, shock-absorbing springs, etc., to mitigate the impact. 3. Humidity interference: When humidity increases, it causes the resistance of insulators to decrease, the dielectric constant to increase, and the structure to become loose; this in turn increases the resistance, leading to an increase in leakage current as well as changes in capacitance and inductance. Furthermore, it softens the colloid, reducing measurement accuracy. 4. Chemical interference: Chemical interference usually refers to some corrosive gases, such as acids and bases. The long-term effect of these gases not only damages the instruments and internal components but also conducts electricity with metals, affecting the proper operation of radar level gauges. 5. Thermal interference: During operation, thermal equipment in thermal power plants generates a large amount of heat, causing changes in the temperature of surrounding instruments and the environment. This is what we call thermal interference. These interferences can affect the components of radar level gauges, leading to issues such as inaccurate measurements. 6. Light interference: Light interference mainly occurs in semiconductor components. Many components used in control instruments are made of semiconductor materials, and the conductivity of these semiconductor components changes under the influence of light. This will affect the proper operation of the radar level gauge. II. Internal interference: Interference comes not only from external sources but also from within the radar level gauge, such as interference caused by wires between power transformers and electronic components, as well as inductors and capacitors. Furthermore, internal components can also generate noise interference. Today, most radar level gauges are also being improved by using high-frequency microwave technology, **which enhances the performance of these level gauges and reduces interference. III. DC interference: In the measurement circuit of radar level gauges, the presence of additional DC current or voltage constitutes DC interference. If the situation is severe, the measuring instruments will not function properly. DC interference sources are as follows: (1) Additional thermoelectric potential. (2) Chemical potential. (3) When the radar level gauge is connected to a DC power supply, the leakage current will generate an interference voltage in the measurement circuit. IV. AC Interference AC interference can be divided into line-to-line interference and ground interference. Line-to-line interference refers to the AC voltage between the output terminals of the radar level gauge (compensation wire) under external influences. This type of interference is also known as lateral, common-mode, or common-terrain interference. Generally, the line-to-line interference voltage can reach several millivolts or even dozens of millivolts. Ground interference refers to one of the two output terminals of a radar level gauge (or compensation wire), and the AC voltage of this terminal with respect to ground is known as the ground interference voltage. This type of interference is also known as longitudinal, series mode, or series-state interference. Generally, the interference voltage relative to the ground can reach several volts or even exceed 100 volts. The main sources of communication interference are as follows: (1) Electromagnetic induction is the primary source of line-to-line interference. (2) High-temperature leakage. (3) High-voltage electric field interference. (4) Ground current interference. (5) Effects of inhalation and leakage. (6) Measuring the temperature on a charged object can also introduce AC interference. That’s all regarding the interferences associated with radar level gauges, as discussed. When installing or using radar level gauges, we can also use the information mentioned above to determine whether your operating environment might cause such interferences to the gauge. If these conditions exist, anti-interference measures must be taken to ensure that the level gauge can serve you better. For more specific usage instructions, please contact the engineers at Xiamen Hongkong at 4000592364
Generally, liquids that contain water are polar materials; if such a liquid adheres to the sensor and reaches a certain threshold, electromagnetic waves cannot be emitted nor retrieved. For some mixing conditions, installing an 80G or 120G radar can solve the problem of level measurement, but there are also many conditions for which it is not suitable.
It’s possible to do this before starting the mixer; once the mixer is running, the radar level gauge becomes useless. To calculate the liquid level in the tank, it is generally done by converting the cumulative flow rate
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