The radar level gauge records the time of the pulse wave, and the transmission speed of the electromagnetic wave is constant, then the distance from the liquid surface to the radar antenna can be calculated, so that the liquid level can be known. In practical applications, there are two methods for radar level gauges: frequency-modulated continuous wave and pulsed wave. The level meter using frequency-modulated continuous wave technology consumes a lot of power and must use a four-wire system. The electronic circuit is complicated. The level gauge using radar pulse wave technology has low power consumption and can be powered by two-wire 24V DC. It is easy to realize intrinsic safety with high accuracy and wider application range. Ultrasonic uses sound waves. Radar uses electromagnetic waves. This is the biggest difference. Moreover, the penetrating ability and directionality of ultrasonic waves are much stronger than those of electromagnetic waves. This is the reason why ultrasonic detection is now more popular.
Professional Granulator used for different kinds of customers special requirement,including the following plastic auxiliary equipment:plastic sheet granulator for production line,plastic pipe granulator for longer or short size
The plastic-pipe granulators of RG-36P series,are mainly used to directly granulate the PVC and PE tubings,PVC sectional and profiled bar.The machine is applicable for crushing long pipes and profiles.The equiped suction conveying and cyclone dust separator system bring recycling efficiency into full play.The machine is characterized with compact structure,atractive appearance,convenient operation,optimized rotation knife to achieve lowest energy consumption and higher cutting efficiency.
New design Powerful granulators RG-2190GQX series,are mainly used to directly granulate different kinds of soft,hard,clumpy,globular,striped andscrap plastic recyling material-The optional Suction Conveying and Cyclone Dust Separator System bring recycling efficinecy into full play.The machine is characterized with compact structure,atractive appearance,convenient operation,optimized rotation knife to achieve lowest energy consumption and higher cutting efficiency.
Professional Granulator Professional Granulator,Professional Industrial Grinder,Professional Shredder,Professional Cutter,Professional Shatter Machine,Professional Granulator For Plastic Industry Ningbo Beilun Rhong Machinery Manufacturing Co., Ltd. , https://www.rhongmachinery.com
We generally refer to sonic waves whose sound wave frequency exceeds 20 kHz as ultrasonic waves. Ultrasonic waves are a kind of mechanical waves, that is, a kind of mechanical vibration propagation process in elastic media. It is characterized by high frequency, short wavelength, and small diffraction phenomenon. With good directionality, it can be ray and directed. Ultrasonic attenuation in liquids and solids is very small, so it has strong penetrability, especially in solids that are opaque to light. Ultrasonic waves can penetrate several tens of meters in length, causing significant reflections when they encounter impurities or interfaces. Ultrasonic Measurements Levels take advantage of this feature.
In the ultrasonic detection technology, no matter what kind of ultrasonic instrument, it must send out the electric energy conversion ultrasonic wave, and then receive back and transform it into the electric signal. The device that accomplishes this function is called the ultrasonic transducer, also called probe. The ultrasonic transducer is placed above the liquid to be measured, and the ultrasonic wave is emitted downward. The ultrasonic wave passes through the air medium and is reflected back upon encountering the water surface, and is received by the transducer and converted into an electric signal. The electronic detection part detects After this signal is turned into a liquid level signal for display and output.
According to the principle of ultrasonic propagation in the medium, if the conditions such as medium pressure, temperature, density, and humidity are constant, the propagation speed of ultrasonic waves in the medium is a constant. Therefore, when measuring the time required for the ultrasonic wave to reach the liquid surface reflection after it is emitted, the distance traveled by the ultrasonic wave can be converted, that is, the liquid level data can be obtained.
There are blind spots in the ultrasonic wave, and the distance between the installation position of the sensor and the liquid to be measured must be calculated during installation.
The main application of the difference:
Ultrasonic level gauges and radar level gauges mainly differ in the principle of measurement, resulting in their different application scenarios. The radar is based on the dielectric constant of the material being measured, and the ultrasound is based on the density of the material being measured. Therefore, the measurement effect of a radar with a low dielectric constant has to be discounted, and ultrasound is generally recommended for solid matter. At the same time, the radar emits electromagnetic waves, which do not require propagation media. Ultrasonic waves are sound waves, which are mechanical waves and require media. In addition, the transmission mode of the wave is different. For example, the ultrasonic wave is emitted by the vibration of the piezoelectric substance, so it cannot be used in the case of high pressure or negative pressure, and it is generally used only in the atmospheric pressure vessel. Radar can be used in high pressure process tanks. Radar emission angle is larger than that of ultrasonic waves. Non-contact radar is not recommended for small vessels or elongated vessels. Guided wave radar is generally recommended. The last is the problem of accuracy. Of course, the accuracy of the radar must be higher than that of the ultrasonic wave. The high-precision radar must be used on the tank and the ultrasonic wave must not be selected. As for the price, ultrasound is generally lower than radar, and of course, some long-range ultrasounds are too high in range and the radar does not work. Therefore, ultrasound can only be selected.
The transmission of sound waves requires media, so it cannot be transmitted in a vacuum. Therefore, the limitations of ultrasound in practical applications are still very large, and there are many disadvantages compared with radar. First of all, the ultrasonic level meter has a temperature limit, generally the temperature at the probe cannot exceed 80 degrees, and the speed of the sound wave is greatly influenced by the temperature. Secondly, the ultrasonic level gauge is greatly influenced by the pressure, generally requiring less than 0.3 MPa because the sound waves are emitted by vibration. When the pressure is too high, the sounding parts will be affected. Third, when the measurement environment has a large amount of fog or dust, it will not be measured very well. All these limits the application of ultrasonic level gauges. In contrast, radar is an electromagnetic wave that is not affected by the degree of vacuum. The application range of medium temperature and pressure is very wide. With the advent of high-frequency radar, its application range is more extensive, so in the level measurement, Radar is a very good choice.
However, whether it is a radar or ultrasonic level gauge, it must pay attention to the installation position during the installation process, pay attention to the blind area. For example, when installing on the tank, do not install it in the feeding port, do not install near the ladder, and have a distance of 300 to 500 mm from the tank wall to prevent echo interference. When stirring, the liquid level fluctuations should also choose the appropriate installation method. In short, there is no perfect thing.
1. The radar measurement range is much larger than ultrasound.
2. Radar has horn type, rod type, cable type, and relative ultrasonic can be applied to more complicated working conditions.
3. Ultrasonic accuracy is not as good as radar.
4. Relatively high price of radar.
5. When using radar, consider the dielectric constant of the medium.
6. Ultrasonic can not be applied to working conditions such as vacuum, excessive steam content, or foam on the liquid surface.
