原理有气相和液相两个取压口。 1. The principle of differential pressure type liquid level gauge has two pressure taking ports of gas phase and liquid phase. In addition to the pressure of the gas phase, the pressure at the pressure point of the liquid phase is also affected by the static pressure of the liquid column, and the difference between the liquid phase and the gas phase pressure is the liquid column.
The occurrence of the generated static pressure, the pressure at the gas pressure taking point is the gas pressure in the equipment
2. The master of the glass tube level gauge and the glass plate level gauge is called a connector type liquid level gauge. The principle of the connector type liquid level gauge is to use the most common glass level gauge. Its characteristics are structure
Simple, inexpensive, and intuitive; suitable for field use, but easy to break, contaminated internal surfaces, cause difficult readings, and inconvenient for remote transmission and adjustment
Such instruments include pneumatic and electric differential pressure transmitters and flanged liquid level transmitters, which are easy to install, easy to realize remote transmission and automatic adjustment, and are widely used in industry.
3. The principle of the capacitive liquid level gauge is to measure the level of the liquid level by measuring the change in capacitance; it is a metal rod inserted into the liquid container, the metal rod is used as one pole of the capacitor, and the container wall is used as the other pole of the capacitor.
The medium between the two electrodes is the liquid and the gas above it; because the dielectric constant ε1 of the liquid and the dielectric constant ε2 on the liquid surface are different, for example: ε1> ε2, when the liquid level rises, the total between the two electrodes Dielectric constant
As the value increases, the capacitance increases. Conversely, when the liquid level decreases, the ε value decreases, and the capacitance decreases.
Therefore, the level of the liquid can be measured by the change in the capacitance between the two electrodes. The sensitivity of the capacitance level meter mainly depends on the difference between the two dielectric constants, and only the constant ε1 and ε2 can be guaranteed.
The liquid level measurement is accurate, because the measured medium has conductivity, so the metal rod electrode is covered by an insulating layer; the capacitive liquid level meter is small in size, easy to realize remote transmission and adjustment, and is suitable for liquid level measurement of corrosive and high pressure media
原理是利用物位的高低对放射形同位素的射线吸收程度不同来测量物位高低的、它的测量范围宽、可用于低温，高温， 4. The principle of the radial level meter is to measure the level of the level by using the difference in the level of absorption of the radioisotope by the level of the level. It has a wide measurement range and can be used for low temperature and high temperature.
Measurement of high viscosity, high corrosion, flammable and explosive media in high pressure vessels
However, such instruments are costly, inconvenient to use and maintain, and harmful to humans due to radiation.
5.The principle of the blown bubble level meter is that Assad should measure the liquid level of the open container using the principle of static pressure.
Compressed air, after filtering the pressure reducing valve, and then outputting a certain pressure through the setting device, it is divided into two ways after the throttling element.
All the way to the tube installed in the container, blow out from the bottom of the container
The other way into the pressure gauge to indicate
When the liquid level is the lowest, there is no resistance to bubble blowing, the pressure is zero, and the pressure gauge is zero. When the liquid level increases, the bubble blows out to overcome the static pressure of the liquid column, the back pressure increases, and the pressure indication increases.
Therefore, the back pressure, the pressure indicated by the pressure gauge, reflects the level of the liquid surface. Bubble level meter has simple structure and low cost, and is suitable for measuring corrosive, viscous and suspended particles.
Liquid level in open containers, but with lower accuracy.
原理是利用超声波在气体、液体或固体中的衰减、穿透能力和声阻抗不同的性质来测量两种介质的界面。 6. The principle of the ultrasonic level meter is to measure the interface between two media by using different properties of ultrasonic attenuation, penetration ability and acoustic impedance in gas, liquid or solid. Such instruments have high accuracy,
The response is fast, but the cost is high and the maintenance is difficult. They are all used in the occasions that require high measurement accuracy.