On 2018-08-08 14:48:54
Dust removal technology of single crystal furnace vacuum system
Vacuum technology has been widely used in metallurgy, chemical industry, light industry, food, medicine and other fields, but in most of these fields there are problems of dust damage to vacuum system. In order to maintain the vacuum system or vacuum pump from dust and solid particles pollution and damage, the pipeline needs to be equipped with vacuum dust remover and vacuum filter. They can maintain the vacuum valve from being blocked, avoid air leakage caused by the valve plate not being closed tightly, maintain the vacuum gauge for measuring pressure from being polluted, and avoid abnormal operation due to pump damage, which is very important for the purification, stability and continuous operation of vacuum equipment.
1、 Dedusting mechanism and process
The dedusting mechanism of collecting separated particles from gas mainly includes the following aspects:
The dust particles in the air flow can be separated from the air flow by relying on the natural settlement of gravity. Because the settling speed of dust particles is usually small, this mechanism is only applicable to coarse dust particles.
2. Centrifugal force
The mechanical force is used to collect the dust in the air stream containing dust. The centrifugal force dedusting equipment is the most useful dedusting equipment. It is very useful for the separation and collection of small dust particles. Because of the effect of the inertial centrifugal force, the dust particles and the air flow will move relative to each other, which makes the dust particles separate from the air flow.
3. Inertia bump and touch retention
When the dusty air flow encounters obstacles (such as baffles, fibers, water drops, etc.) in the process of movement, the air flow should change its direction to flow around, and the fine dust particles will move with the air flow. The coarse dust particles have a large inertia, which will break away from the streamline and adhere to their own inertial motion, so that the dust particles will collide with the object and break away from the air flow. When fine dust particles flow along with the air flow, if the flow line is close to the surface of the object (fiber or liquid drop), some dust particles will be blocked due to touching with the object, this appearance is called touch blocking. In addition, when the size of dust particles is larger than the fiber mesh and is blocked, this appearance is called screening effect.
4. Brownian dispersion
When the particle size of dust particles in the dusty air flow is less than 1lm, especially less than 0.1lm, these particles will no longer flow around the trap along the gas flow line when they move with the air flow, so they can no longer follow the mechanism of inertia collision or touch retention to catch and separate the trap, and another trapping mechanism - dispersion plays an effect. Because of the irregular movement caused by the thermal movement between gas molecules, the irregular movement caused by the thermal movement between gas molecules makes the gas molecules bombard the dust particles and make the particles Brownian dispersion, which can make the dust particles evenly distributed in all gas spaces. It is thought that if an object is placed in the gas, some ultra-fine particles will settle on the surface of the object through Brownian dispersion, so that these ultra-fine particles can be trapped and separated from the gas.
5. Electrostatic power
Dust particles suspended in the air flow, if with a certain electric charge, can be separated from the air flow by electrostatic force. Because the charge of dust particles is very small in the natural state, it is necessary to set a special high-voltage electric field to make all dust particles fully charged in order to get better dust removal effect.
The agglutination effect is not a direct dedusting mechanism. After ultrasonic, steam agglutination, humidification and other agglutination effects, the agglutination of small particles can be increased, and then removed by the usual dust removal method.