Application principle of level sensor
The level sensor can be divided into two categories: one is a continuous level sensor that continuously measures the level change; the other is a switch level sensor that is a point meter for the point measurement. Currently, switch level sensors are widely used than continuous level sensors. It is mainly used for threshold control, overflow and idling prevention of process automatic control. Continuous level sensors are mainly used for continuous control and warehouse management, and sometimes for multi-point alarm systems. The following describes several practical level sensors and applications. 1. Capacitive Level Sensor The capacitive level sensor has two conductor electrodes (usually using the vessel wall as an electrode). Because of the change of electrostatic capacitance caused by gas, fluid or solid between the electrodes, the level can be sensitive. Its sensitive components are available in three forms, namely rods, wires and plates. The operating temperature and pressure are mainly limited by the insulating material. Capacitive level sensor can be controlled by microcomputer, realizes automatic adjustment sensitivity, and has self-diagnosis function. It can also detect damage of sensitive components, reduce insulation, cable and circuit faults, etc., and can automatically alarm and achieve high reliability. Sexual information transfer. Since the capacitive level sensor has no mechanical movable part, and the sensitive component is simple, the shape and structure are free to be large and easy to operate, it is the most widely used level sensor. 2. Float level sensor This sensor measures the liquid level by detecting changes in the balance float buoyancy. It can be equipped with a microcomputer to provide self-test, self-diagnosis and remote transmission functions, which can be used to measure the liquid level of a large span with high precision. 3. The pressure level sensor generally adopts a semiconductor bellows structure, and the metal sheet is subjected to liquid pressure. The sealed silicon oil is guided to the semiconductor strain gauge for liquid level measurement. Due to the improved performance of solid state pressure sensors (piezoresistive bridge type) and the development of micro-processing technology, the application of pressure level sensors is becoming more and more extensive. In recent years, pressure-type level sensors with small size, wide temperature range, high reliability and high precision have been developed, and their application range has been continuously expanded. 4. Ultrasonic level sensor It is a non-contact level sensor with a wide range of applications. The working principle is that a beam of ultrasonic waves is emitted to the surface of the liquid surface or the powder during operation, and after being reflected by the sensor, the sensor receives the reflected wave. Set the speed of sound to be constant, and calculate the distance from the suction device to the liquid surface (the surface of the powder) according to the time of the round-trip of the sound wave, that is, the position of the liquid surface (powder surface) is measured. There are two kinds of sensitive components, one is composed of a coil, a magnet and a film, and the other is composed of a piezoelectric magnetostrictive material. The former produces 10KHz ultrasonic waves, and the latter produces ultrasonic waves of 20~40Khz. The lower the frequency of the ultrasonic wave, the smaller the attenuation with distance, but the reflection efficiency is also small. Therefore, the ultrasonic sensor used should be determined according to the measurement range, the surface condition of the level, and the surrounding environmental conditions. The high performance ultrasonic level sensor is controlled by a microcomputer. Feature adjustment and function detection in compact hardware. It accurately distinguishes between signal waves and noise, so the level can be measured while the agitator is operating. In addition, the level can be detected at high temperatures or during blowing, in particular, it can detect the level of high-viscosity liquid and powder. 5. Laser level sensor It is a non-contact high-precision level sensor with excellent performance. The working principle is the same as that of the ultrasonic level sensor, except that the ultrasonic wave is replaced by a light wave. The laser beam is very thin. As a level sensor, even if the surface of the level is extremely rough, the reflected beam is not widened to 20mm, but it is still within the range that the laser level sensor can receive, and the laser level sensor is generally used. Near infrared light. It is a laser that emits light from a stream using a semi-transmissive mirror. One part is used as the reference reference signal to input the time transmitter, and the other part is processed by the optical system through the laser of the semi-transmissive mirror to become a parallel beam of a certain width to illuminate the object surface. The reflected wave reaches the sensor receiving portion and is converted into an electrical signal. Since the time from irradiation to acceptance is short, the sampling circuit is expanded to the order of nanoseconds to facilitate signal processing and time measurement. Using the microcomputer to perform data processing, it becomes an analog output signal that digitally displays the level value, and then uses the software to detect the reliable part of the signal. If the measurement system fails, it will alarm. This sensor can be used to measure the level of sand-type molten iron in the continuous casting equipment of the steel industry. At the same time, it can also be applied to narrow open containers as well as high temperature, high precision liquid level detection. In addition, in recent years, with the development of high technology, a digital intelligent level sensor has emerged, which is an advanced digital level measurement system. Combining its measuring component technology with the computing functions of the microprocessor, the level measuring instrument to the control instrument becomes a fully digital system. The comprehensive performance index and actual measurement accuracy of the digital intelligent level sensor are 3-5 times higher than the traditional analog level sensor. In short, with the development of sensor technology, the form of the level sensor will be various, and its form should be focused on non-contact. Its development direction is to further improve the overall performance through the extensive application of high-tech electronic technologies such as microcomputers, and to develop in the direction of miniaturization, intelligence, and multi-functionality. Concerned about surprises Label: Application principle Piezoresistive Sampling circuit Container wall Magnetostrictive material Previous: How to buy faucets and showers Next: Sensor installation precautions
Ferroalloys, a
broadly defined ferroalloy is a product that is used as a deoxidizer, elemental
additive, etc. in steelmaking to add iron to certain properties or to meet
certain requirements.
Property: The main element of the ferroalloy generally
has a high melting point, or its oxide is difficult to reduce, and it is
difficult to refine the pure metal. If it is together with the iron, it is
easier to reduce the smelting. The use of ferroalloys in iron and steel
smelting, in which iron is not only harmless, but because of the fusing of
molten steel is more favorable. Therefore, deoxidation and alloying in the
steelmaking process are mostly added in the form of iron alloys. Iron alloys
are generally brittle and cannot be used as metal materials.
Purpose: As a deoxidizer for steelmaking, silicon
manganese, ferromanganese and ferrosilicon are the most widely used . As strong
deoxidizers, aluminum (aluminum iron), silicon calcium, silicon zirconium, etc
are used . Commonly used alloy additives
are: ferromanganese, ferrochromium, ferrosilicon, ferrotungsten,
ferromolybdenum, ferrovanadium, ferrotitanium, ferronickel, niobium (neodymium)
iron, rare earth iron alloy, ferroboron, ferrophosphorus and so on. A variety
of ferroalloys, in accordance with steelmaking needs, are regulated in many
grades based on the content of alloying elements or the level of Carbon
contained, and the impurity content is strictly limited. Ferroalloys containing
two or more alloying elements are called composite ferroalloys. The use of such
ferroalloys can add deoxidizing or alloying elements at the same time, which is
beneficial to the steelmaking process and enables the more comprehensive and
efficient utilization of symbiotic ore resources. Commonly used: manganese
silicon, silicon calcium, silicon zirconium, silicon manganese aluminum,
silicon manganese calcium and rare earth ferrosilicon.
Ferroalloys Ferroalloys,Ferro Silicon,Ferro Tungsten,Different Shape Ferroalloys Hwa Seng Resources (Hong Kong) Co., Limited , https://www.hwaseng-resources.com