Process Engineering Division – Instrumentation and Automation Section – Daily Question – Question from 2020-11-04

The principle of measurement is different; one involves electromagnetic waves, while the other involves mechanical waves. Radar emits electromagnetic waves, which do not require a medium for propagation, whereas ultrasonic waves are sound waves, a type of mechanical wave that is generated through the vibration of piezoelectric materials; therefore, it cannot be used in environments with high pressure or negative pressure, and is generally only used in containers at normal pressure. Radar, on the other hand, can be used in process tanks under high pressure. Moreover, the accuracy of radar is definitely higher than that of ultrasonic sensors; it is better to use radar for measuring the liquid level in chlorine storage tanks, although it is more expensive. Ultrasonic waves can only be used in containers at atmospheric pressure. The fundamental reason for this is that the wave speed of ultrasonic waves is related to the pressure and temperature of the medium being measured (air). Generally, the sensor part of ultrasonic level gauges is equipped with a temperature sensor that allows for temperature compensation, but pressure compensation is not possible. Radar emits electromagnetic waves, and the speed of these waves is independent of pressure and temperature; therefore it is suitable for measuring the liquid level in pressure vessels. The reflection intensity of ultrasound is related to the densities on both sides of the interface; the greater the difference in density, the stronger the reflected signal ； The reflection intensity of radar is related to the dielectric constants on both sides of the interface; the greater the difference in ε, the stronger the reflected signal

Different features of radar level gauges and ultrasonic level gauges: 1. Different principles. Radar uses electromagnetic waves, while ultrasonic level gauges use sound waves. 2. The application scenarios are different. 1) Radar level gauges use electromagnetic waves, which are affected by the dielectric constant of the substance being measured, whereas ultrasonic waves are mechanical waves that are influenced by the density of the medium in question. Therefore, when measuring materials with very low dielectric constants, the performance of radar level gauges is significantly reduced, making them unsuitable for such measurements. 2) The measurement range of radar level gauges is much larger than that of ultrasonic level gauges. Radar emits electromagnetic waves, allowing measurements to be taken without the need for a medium of propagation. Ultrasonic waves, on the other hand, are sound waves and mechanical waves that require a medium for propagation. Therefore, ultrasonic level gauges cannot be used in conditions such as vacuum, high steam content, or liquid surfaces with foam. Ultrasonic level gauges have temperature limitations; generally, the temperature at the probe should not exceed 80 degrees, and the speed of sound is greatly affected by temperature. Ultrasonic level gauges are highly sensitive to pressure; generally, a pressure level of less than 0.3 MPa is required, as sound waves are generated through vibration, and high pressure can affect the components responsible for producing sound. When there is a lot of fog or dust in the measurement environment, ultrasonic level gauges cannot perform accurate measurements either. In contrast, radar uses electromagnetic waves, is not affected by vacuum, and has a wide range of applicability across different temperatures and pressures of the medium; with the advent of high-frequency radar, its applications have become even broader, while ultrasonic level gauges are subject to many more limitations. 3) The components used for generating the two types of waves are different; for example, ultrasonic waves are generated through the vibration of piezoelectric materials. Therefore, ultrasonic level gauges cannot be used in environments with high pressure or negative pressure, and are generally used only in containers at normal pressure. Radar level gauges, on the other hand, can be used in high-pressure process tanks. 4) The transmission angle of radar is greater than that of ultrasonic waves; therefore, contactless radar is not recommended for small or elongated containers, and guided-wave radar is generally preferred. Finally, there are the issues related to precision. Of course, the precision of radar is definitely higher than that of ultrasound; high-precision radar is used in storage tanks, rather than ultrasound. 5) Radar level gauges come in horn-type, rod-type, and cable-type versions, and can be used in various measurement scenarios; therefore, compared to ultrasonic level gauges, radar level gauges can be applied to more complex conditions. 6) In terms of price, radar level gauges are relatively more expensive compared to ultrasonic level gauges. Of course, some ultrasonic sensors with a large measurement range also come at a high price; for ranges of 6 to 70 meters, even radar level gauges with very large ranges cannot handle such measurements, so ultrasonic level gauges are the only option. 3. Points to note: Whether it is a radar level gauge or an ultrasonic level gauge, care must be taken regarding the installation location and blind spots during installation. For example, when installing it on a tank, do not place it at the feed inlet or near a ladder; it should be kept 300 to 500 mm away from the tank wall to avoid interference from echoes. In situations with stirring and large surface fluctuations, an appropriate installation method must also be chosen.

Different features of radar level gauges and ultrasonic level gauges: 1. Different principles. Radar uses electromagnetic waves, while ultrasonic level gauges use sound waves. 2. The application scenarios are different. 1) Radar level gauges use electromagnetic waves, which are affected by the dielectric constant of the substance being measured, whereas ultrasonic waves are mechanical waves that are influenced by the density of the medium in question. Therefore, when measuring materials with very low dielectric constants, the performance of radar level gauges is significantly reduced, making them unsuitable for such measurements. 2) The measurement range of radar level gauges is much larger than that of ultrasonic level gauges. Radar emits electromagnetic waves, allowing measurements to be taken without the need for a medium of propagation. Ultrasonic waves, on the other hand, are sound waves and mechanical waves that require a medium for propagation. Therefore, ultrasonic level gauges cannot be used in conditions such as vacuum, high steam content, or liquid surfaces with foam. Ultrasonic level gauges have temperature limitations; generally, the temperature at the probe should not exceed 80 degrees, and the speed of sound is greatly affected by temperature. Ultrasonic level gauges are highly sensitive to pressure; generally, a pressure level of less than 0.3 MPa is required, as sound waves are generated through vibration, and high pressure can affect the components responsible for producing sound. When there is a lot of fog or dust in the measurement environment, ultrasonic level gauges cannot perform accurate measurements either. In contrast, radar uses electromagnetic waves, is not affected by vacuum, and has a wide range of applicability across different temperatures and pressures of the medium; with the advent of high-frequency radar, its applications have become even broader, while ultrasonic level gauges are subject to many more limitations. 3) The components used for generating the two types of waves are different; for example, ultrasonic waves are generated through the vibration of piezoelectric materials. Therefore, ultrasonic level gauges cannot be used in environments with high pressure or negative pressure, and are generally used only in containers at normal pressure. Radar level gauges, on the other hand, can be used in high-pressure process tanks. 4) The transmission angle of radar is greater than that of ultrasonic waves; therefore, contactless radar is not recommended for small or elongated containers, and guided-wave radar is generally preferred. Finally, there are the issues related to precision. Of course, the precision of radar is definitely higher than that of ultrasound; high-precision radar is used in storage tanks, rather than ultrasound. 5) Radar level gauges come in horn-type, rod-type, and cable-type versions, and can be used in various measurement scenarios; therefore, compared to ultrasonic level gauges, radar level gauges can be applied to more complex conditions. 6) In terms of price, radar level gauges are relatively more expensive compared to ultrasonic level gauges. Of course, some ultrasonic sensors with a large measurement range also come at a high price; for ranges of 6 to 70 meters, even radar level gauges with very large ranges cannot handle such measurements, so ultrasonic level gauges are the only option. 3. Points to note: Whether it is a radar level gauge or an ultrasonic level gauge, care must be taken regarding the installation location and blind spots during installation. For example, when installing it on a tank, do not place it at the feed inlet or near a ladder; it should be kept 300 to 500 mm away from the tank wall to avoid interference from echoes. In situations with stirring and large surface fluctuations, an appropriate installation method must also be chosen.

Different features of radar level gauges and ultrasonic level gauges: 1. Different principles. Radar uses electromagnetic waves, while ultrasonic level gauges use sound waves. 2. The application scenarios are different. 1) Radar level gauges use electromagnetic waves, which are affected by the dielectric constant of the substance being measured, whereas ultrasonic waves are mechanical waves that are influenced by the density of the medium in question. Therefore, when measuring materials with very low dielectric constants, the performance of radar level gauges is significantly reduced, making them unsuitable for such measurements. 2) The measurement range of radar level gauges is much larger than that of ultrasonic level gauges. Radar emits electromagnetic waves, allowing measurements to be taken without the need for a medium of propagation. Ultrasonic waves, on the other hand, are sound waves and mechanical waves that require a medium for propagation. Therefore, ultrasonic level gauges cannot be used in conditions such as vacuum, high steam content, or liquid surfaces with foam. Ultrasonic level gauges have temperature limitations; generally, the temperature at the probe should not exceed 80 degrees, and the speed of sound is greatly affected by temperature. Ultrasonic level gauges are highly sensitive to pressure; generally, a pressure level of less than 0.3 MPa is required, as sound waves are generated through vibration, and high pressure can affect the components responsible for producing sound. When there is a lot of fog or dust in the measurement environment, ultrasonic level gauges cannot perform accurate measurements either. In contrast, radar uses electromagnetic waves, is not affected by vacuum, and has a wide range of applicability across different temperatures and pressures of the medium; with the advent of high-frequency radar, its applications have become even broader, while ultrasonic level gauges are subject to many more limitations. 3) The components used for generating the two types of waves are different; for example, ultrasonic waves are generated through the vibration of piezoelectric materials. Therefore, ultrasonic level gauges cannot be used in environments with high pressure or negative pressure, and are generally used only in containers at normal pressure. Radar level gauges, on the other hand, can be used in high-pressure process tanks. 4) The transmission angle of radar is greater than that of ultrasonic waves; therefore, contactless radar is not recommended for small or elongated containers, and guided-wave radar is generally preferred. Finally, there are the issues related to precision. Of course, the precision of radar is definitely higher than that of ultrasound; high-precision radar is used in storage tanks, rather than ultrasound. 5) Radar level gauges come in horn-type, rod-type, and cable-type versions, and can be used in various measurement scenarios; therefore, compared to ultrasonic level gauges, radar level gauges can be applied to more complex conditions. 6) In terms of price, radar level gauges are relatively more expensive compared to ultrasonic level gauges. Of course, some ultrasonic sensors with a large measurement range also come at a high price; for ranges of 6 to 70 meters, even radar level gauges with very large ranges cannot handle such measurements, so ultrasonic level gauges are the only option. 3. Points to note: Whether it is a radar level gauge or an ultrasonic level gauge, care must be taken regarding the installation location and blind spots during installation. For example, when installing it on a tank, do not place it at the feed inlet or near a ladder; it should be kept 300 to 500 mm away from the tank wall to avoid interference from echoes. In situations with stirring and large surface fluctuations, an appropriate installation method must also be chosen.

1. Ultrasonic level gauge: As a non-contact measurement method that has seen rapid development in recent years, ultrasonic technology is widely used in the field of level measurement. Ultrasonic level gauges that use ultrasonic technology for level measurement emit mechanical waves, which experience very little attenuation in liquids and solids; as a result, they have strong penetration capabilities. They undergo significant reflection once they encounter an obstacle or the liquid surface. Ultrasonic level gauges feature high frequency, short wavelength, minimal diffraction, good directionality, strong penetration ability, and the capability to propagate in a directed manner as rays. 2. Radar level gauge: The electromagnetic waves emitted by a radar level gauge have strong penetration power, and their propagation speed is not affected by dust, steam, or the components of the medium; moreover, the attenuation of these waves during propagation is very low. The temperature, pressure, density, etc., of the medium have almost no effect on its accurate measurement. On-site calibration is simple; using specialized software, the correct echo can be quickly identified and immediately converted into a level value.

Different features of radar level gauges and ultrasonic level gauges: 1. Different principles. Radar uses electromagnetic waves, while ultrasonic level gauges use sound waves. 2. The application scenarios are different. 1) Radar level gauges use electromagnetic waves, which are affected by the dielectric constant of the substance being measured, whereas ultrasonic waves are mechanical waves that are influenced by the density of the medium in question. Therefore, when measuring materials with very low dielectric constants, the performance of radar level gauges is significantly reduced, making them unsuitable for such measurements. 2) The measurement range of radar level gauges is much larger than that of ultrasonic level gauges. Radar emits electromagnetic waves, allowing measurements to be taken without the need for a medium of propagation. Ultrasonic waves, on the other hand, are sound waves and mechanical waves that require a medium for propagation. Therefore, ultrasonic level gauges cannot be used in conditions such as vacuum, high steam content, or liquid surfaces with foam. Ultrasonic level gauges have temperature limitations; generally, the temperature at the probe should not exceed 80 degrees, and the speed of sound is greatly affected by temperature. Ultrasonic level gauges are highly sensitive to pressure; generally, a pressure level of less than 0.3 MPa is required, as sound waves are generated through vibration, and high pressure can affect the components responsible for producing sound. When there is a lot of fog or dust in the measurement environment, ultrasonic level gauges cannot perform accurate measurements either. In contrast, radar uses electromagnetic waves, is not affected by vacuum, and has a wide range of applicability across different temperatures and pressures of the medium; with the advent of high-frequency radar, its applications have become even broader, while ultrasonic level gauges are subject to many more limitations. 3) The components used for generating the two types of waves are different; for example, ultrasonic waves are generated through the vibration of piezoelectric materials. Therefore, ultrasonic level gauges cannot be used in environments with high pressure or negative pressure, and are generally used only in containers at normal pressure. Radar level gauges, on the other hand, can be used in high-pressure process tanks. 4) The transmission angle of radar is greater than that of ultrasonic waves; therefore, contactless radar is not recommended for small or elongated containers, and guided-wave radar is generally preferred. Finally, there are the issues related to precision. Of course, the precision of radar is definitely higher than that of ultrasound; high-precision radar is used in storage tanks, rather than ultrasound. 5) Radar level gauges come in horn-type, rod-type, and cable-type versions, and can be used in various measurement scenarios; therefore, compared to ultrasonic level gauges, radar level gauges can be applied to more complex conditions. 6) In terms of price, radar level gauges are relatively more expensive compared to ultrasonic level gauges. Of course, some ultrasonic sensors with a large measurement range also come at a high price; for ranges of 6 to 70 meters, even radar level gauges with very large ranges cannot handle such measurements, so ultrasonic level gauges are the only option. 3. Points to note: Whether it is a radar level gauge or an ultrasonic level gauge, care must be taken regarding the installation location and blind spots during installation. For example, when installing it on a tank, do not place it at the feed inlet or near a ladder; it should be kept 300 to 500 mm away from the tank wall to avoid interference from echoes. In situations with stirring and large surface fluctuations, an appropriate installation method must also be chosen.

Different features of radar level gauges and ultrasonic level gauges: 1. Different principles. Radar uses electromagnetic waves, while ultrasonic level gauges use sound waves. 2. The application scenarios are different. 1) Radar level gauges use electromagnetic waves, which are affected by the dielectric constant of the substance being measured, whereas ultrasonic waves are mechanical waves that are influenced by the density of the medium in question. Therefore, when measuring materials with very low dielectric constants, the performance of radar level gauges is significantly reduced, making them unsuitable for such measurements. 2) The measurement range of radar level gauges is much larger than that of ultrasonic level gauges. Radar emits electromagnetic waves, allowing measurements to be taken without the need for a medium of propagation. Ultrasonic waves, on the other hand, are sound waves and mechanical waves that require a medium for propagation. Therefore, ultrasonic level gauges cannot be used in conditions such as vacuum, high steam content, or liquid surfaces with foam. Ultrasonic level gauges have temperature limitations; generally, the temperature at the probe should not exceed 80 degrees, and the speed of sound is greatly affected by temperature. Ultrasonic level gauges are highly sensitive to pressure; generally, a pressure level of less than 0.3 MPa is required, as sound waves are generated through vibration, and high pressure can affect the components responsible for producing sound. When there is a lot of fog or dust in the measurement environment, ultrasonic level gauges cannot perform accurate measurements either. In contrast, radar uses electromagnetic waves, is not affected by vacuum, and has a wide range of applicability across different temperatures and pressures of the medium; with the advent of high-frequency radar, its applications have become even broader, while ultrasonic level gauges are subject to many more limitations. 3) The components used for generating the two types of waves are different; for example, ultrasonic waves are generated through the vibration of piezoelectric materials. Therefore, ultrasonic level gauges cannot be used in environments with high pressure or negative pressure, and are generally used only in containers at normal pressure. Radar level gauges, on the other hand, can be used in high-pressure process tanks. 4) The transmission angle of radar is greater than that of ultrasonic waves; therefore, contactless radar is not recommended for small or elongated containers, and guided-wave radar is generally preferred. Finally, there are the issues related to precision. Of course, the precision of radar is definitely higher than that of ultrasound; high-precision radar is used in storage tanks, rather than ultrasound. 5) Radar level gauges come in horn-type, rod-type, and cable-type versions, and can be used in various measurement scenarios; therefore, compared to ultrasonic level gauges, radar level gauges can be applied to more complex conditions.

Similarities: Both can perform contactless measurements. Differences: 1. Ultrasound uses sound waves, while radar uses electromagnetic waves. 2. Radar relies on the dielectric constant of the material being measured, whereas ultrasound depends on the density of that material.

Different features of radar level gauges and ultrasonic level gauges: 1. Different principles. Radar uses electromagnetic waves, while ultrasonic level gauges use sound waves. 2. The application scenarios are different. 1) Radar level gauges use electromagnetic waves, which are affected by the dielectric constant of the substance being measured, whereas ultrasonic waves are mechanical waves that are influenced by the density of the medium in question. Therefore, when measuring materials with very low dielectric constants, the performance of radar level gauges is significantly reduced, making them unsuitable for such measurements. 2) The measurement range of radar level gauges is much larger than that of ultrasonic level gauges. Radar emits electromagnetic waves, allowing measurements to be taken without the need for a medium of propagation. Ultrasonic waves, on the other hand, are sound waves and mechanical waves that require a medium for propagation. Therefore, ultrasonic level gauges cannot be used in conditions such as vacuum, high steam content, or liquid surfaces with foam. Ultrasonic level gauges have temperature limitations; generally, the temperature at the probe should not exceed 80 degrees, and the speed of sound is greatly affected by temperature. Ultrasonic level gauges are highly sensitive to pressure; generally, a pressure level of less than 0.3 MPa is required, as sound waves are generated through vibration, and high pressure can affect the components responsible for producing sound. When there is a lot of fog or dust in the measurement environment, ultrasonic level gauges cannot perform accurate measurements either. In contrast, radar uses electromagnetic waves, is not affected by vacuum, and has a wide range of applicability across different temperatures and pressures of the medium; with the advent of high-frequency radar, its applications have become even broader, while ultrasonic level gauges are subject to many more limitations. 3) The components used for generating the two types of waves are different; for example, ultrasonic waves are generated through the vibration of piezoelectric materials. Therefore, ultrasonic level gauges cannot be used in environments with high pressure or negative pressure, and are generally used only in containers at normal pressure. Radar level gauges, on the other hand, can be used in high-pressure process tanks. 4) The transmission angle of radar is greater than that of ultrasonic waves; therefore, contactless radar is not recommended for small or elongated containers, and guided-wave radar is generally preferred. Finally, there are the issues related to precision. Of course, the precision of radar is definitely higher than that of ultrasound; high-precision radar is used in storage tanks, rather than ultrasound. 5) Radar level gauges come in horn-type, rod-type, and cable-type versions, and can be used in various measurement scenarios; therefore, compared to ultrasonic level gauges, radar level gauges can be applied to more complex conditions. 6) In terms of price, radar level gauges are relatively more expensive compared to ultrasonic level gauges. Of course, some ultrasonic sensors with a large measurement range also come at a high price; for ranges of 6 to 70 meters, even radar level gauges with very large ranges cannot handle such measurements, so ultrasonic level gauges are the only option. 3. Points to note: Whether it is a radar level gauge or an ultrasonic level gauge, care must be taken regarding the installation location and blind spots during installation. For example, when installing it on a tank, do not place it at the feed inlet or near a ladder; it should be kept 300 to 500 mm away from the tank wall to avoid interference from echoes. In situations with stirring and large surface fluctuations, an appropriate installation method must also be chosen.

Radar level gauges emit electromagnetic waves, while ultrasonic level gauges emit sound waves.