1 产品概述
1.1 Product Overview:
袋式除尘器是利用多孔的袋装过滤元件从含尘气体中捕集粉尘的一种除尘设备。主要由过滤装置和清尘装置两个部分组成。前者的作用是捕集粉尘;后者则用以定期清除滤袋上的积尘,保持除尘器的处理能力。通常还设有清灰控制装置,是除尘器按一定的时间间隔和程序清灰。
Bag filter is a kind of dust removal equipment that collects dust from dust-containing gas by means of porous bag filter element. It mainly consists of filter device and dust removal device. The former role is to catch dust; The latter is used to regularly eliminate the dust on the filter bag to maintain the processing capacity of the dust collector. Usually also has the ash control device, is the dust collector according to the certain time interval and the procedure ash clearance, generally thinks the bag type dust collector certain time interval and the procedure ash clearance
2. 过滤材料对尘粒的捕集
2.1. Filter material's collection of dust particles.
这一过程中包括观星碰撞效应、截留效应、扩散效应、静电效应、筛滤效应、重力沉降效应。
一般粒径较大的粉尘主要依碰效应捕集,当含尘气流接近滤料的纤维时,秋柳流线围绕捕集纤维迅速拐弯,其中较大的粒子由于惯性力的作用,偏离了流线,继续沿着原来的运动方向前进,同捕集纤维发生碰撞而被捕集。惯性碰撞时过滤除尘的主要机制之一,而尘粒能否同捕集纤维发生碰撞主要取决于运动粒子所具有的惯性力于的大有小,为了的提高惯,性可碰撞效以应,可的以适当生提高通如过滤料果的气流的流速。
对于具有一定尺寸直径的尘粒，质量可以忽略的尘粒，如果依据流线把他们带到距捕集纤维表面d/2以内的距离***会被捕集。
在气流中对于粒径小于1m的尘粒由于气体分子的运动撞击,使其产生布朗悦动。这种尘粒无规则的运动,除了可能产生尘粒之间的凝集外,还有向低浓度区扩散的趋势。由于捕集纤维表面的浓度较低,所以小尘粒向着纤维表面扩散,并与纤维碰撞而被捕集。当过滤速度较高时,扩散效应***会下降。
有许多人造纤维编织的滤料,当气流穿过时,由于摩擦产生静电现象,同时有许多粉尘在输送过程中也会由于摩擦或其他基质使其带有电荷,这样***可能在滤料和尘粒之间形成一个电位差,当尘粒随着气流趋向滤料时,由于库仑力作用,促使粉尘和滤料纤维碰撞并增强滤料对粉尘吸附力而被捕集,从而提高过滤效率。
当尘粒的粒径大于滤料孔隙时,尘粒即被滤料孔隙筛滤下来,因此筛滤效应能捕集粒径大于孔隙的粉尘。当粉尘沉集在滤料表面上而使滤料孔隙变小时,粒径较小的颢粒也不能从孔通过从而被捕集,随着粉尘层的形成和加厚,筛滤拥集效率会显著提高。
对于粒径大、密度大的尘粒,在重力作用下可以自然沉降到滤料上,这种作用称为重力沉降效应。
2. 过滤材料对尘粒的捕集
2.1. Filter material's collection of dust particles.
This process includes stargazing collision effect, interception effect, diffusion effect, electrostatic effect, screening effect and gravity subsidence effect.
Generally, dust with large particle size mainly depends on impact effect. When the dusty air flow is close to the fiber of the filter material, the catch fiber quickly turns around on the flow line of the autumn willow, and the larger particles deviate from the flow line due to the action of inertial force, continue to move along the original direction, and get caught in collision with the catch fiber. In inertial collision, one of the main mechanisms of filtration and dedusting, and whether the dust particle can collide with the capturing fiber mainly depends on the size of the inertial force of the moving particle.
For dust particles of a certain size and diameter, particles of negligible mass will be trapped if the flow lines according to them bring them within d/2 of the surface of the trapping fiber.
For dust particles with particle size less than 1um in the airflow, Brownian motion is generated due to the collision of gas molecules. In addition to the possibility of agglutination between dust particles, the random movement of dust particles also tends to spread to low concentration areas. Because of the low concentration on the fiber surface, the small dust particles expand towards the fiber surface and collide with the fiber and get trapped. When the filtration speed is high, the diffusion effect will decrease.
There are many man-made fiber woven filter material, when the airflow through the electrostatic phenomenon due to friction, at the same time there are a lot of dust in the process of delivery will be due to friction or other substrate with charge, so that it may be in the filter material and form a potential difference between dust particles, when the dust particles as they tend to filter material, because of the coulomb force, prompting dust and strong collision and rights of filter material fibre was arrested for dust adsorption force, so as to improve the efficiency of filtering.
When the particle size of the dust particle is larger than the pore size of the filter material, the dust particle is filtered by the filter material pore, so the sieve effect can capture the dust particle size larger than the pore size. When the dust sinks on the surface of the filter material and the pores of the filter material become small, the particles with small size cannot pass through the pores and thus get trapped. With the formation and thickening of the dust layer, the screening efficiency will be significantly improved.
3 粉尘层对尘粒的捕集
3.1 Dust layer traps dust particles
如前所述,过滤操作一定时间后,由于粘附等作用,尘粒在滤料网孔间产生架桥现象,使气流通过滤料的孔径变得很小,从而使滤料网孔及其表面迅速截留粉尘形成粉尘层,当清灰后依照残留一定厚度的粉尘,称为粉尘初层。由于粉尘初层中粉尘粒径通常都比纤维小,因此筛滤、惯性、截留和扩散等作用都有所增加,使除尘效率显著提高。由此可见,袋式尘器的高效率,粉尘初层起着比滤料本身更为重要的作用,一般合成纤维布的网孔为20-50m,如为起毛的则为5-10 m,用这样的滤料,只要设计得当,***是0.1pm的尘粒也能获得将近****的除尘效率。
当滤袋表面积积附的粉尘层厚到一定程度时,需要对滤袋进行清灰,以******滤袋持续工作所需的透气性。袋式除尘器正是在这种不断滤尘而又不断清灰的交替过程中进行工作的。
3 粉尘层对尘粒的捕集
3.1 Dust layer traps dust particles
As mentioned above, after a certain time of filtration operation, due to adhesion and other effects, dust particles will bridge between the filter mesh, making the pore diameter of the filter material in air circulation become very small, so that the filter mesh and its surface can quickly intercept dust to form a dust layer. When the dust is cleaned, according to the residual dust of a certain thickness, it is called the initial dust layer. Since the particle size of dust in the initial layer of dust is usually smaller than that of the fiber, screening, inertia, interception and diffusion are all increased, which significantly improves the dust removal efficiency. It can be seen that the high efficiency of the bag filter, dust primary layer plays a more important role than the filter itself. Generally speaking, the mesh of synthetic fiber cloth is 20-50m, and if it is fluffiness, it is 5-10um. With such filter material, as long as it is properly designed, the dust particle of 0.1um can achieve nearly **** dust removal efficiency.
When the dust layer accumulated on the surface area of the filter bag is thick enough, it is necessary to clean the filter bag to ensure the air permeability required by the continuous work of the filter bag. It is in this alternating process of continuous dust filtering and continuous dust removal that the bag filter works.
2.1. Filter material's collection of dust particles.
This process includes stargazing collision effect, interception effect, diffusion effect, electrostatic effect, screening effect and gravity subsidence effect.
Generally, dust with large particle size mainly depends on impact effect. When the dusty air flow is close to the fiber of the filter material, the catch fiber quickly turns around on the flow line of the autumn willow, and the larger particles deviate from the flow line due to the action of inertial force, continue to move along the original direction, and get caught in collision with the catch fiber. In inertial collision, one of the main mechanisms of filtration and dedusting, and whether the dust particle can collide with the capturing fiber mainly depends on the size of the inertial force of the moving particle.
For dust particles of a certain size and diameter, particles of negligible mass will be trapped if the flow lines according to them bring them within d/2 of the surface of the trapping fiber.
For dust particles with particle size less than 1um in the airflow, Brownian motion is generated due to the collision of gas molecules. In addition to the possibility of agglutination between dust particles, the random movement of dust particles also tends to spread to low concentration areas. Because of the low concentration on the fiber surface, the small dust particles expand towards the fiber surface and collide with the fiber and get trapped. When the filtration speed is high, the diffusion effect will decrease.
There are many man-made fiber woven filter material, when the airflow through the electrostatic phenomenon due to friction, at the same time there are a lot of dust in the process of delivery will be due to friction or other substrate with charge, so that it may be in the filter material and form a potential difference between dust particles, when the dust particles as they tend to filter material, because of the coulomb force, prompting dust and strong collision and rights of filter material fibre was arrested for dust adsorption force, so as to improve the efficiency of filtering.
When the particle size of the dust particle is larger than the pore size of the filter material, the dust particle is filtered by the filter material pore, so the sieve effect can capture the dust particle size larger than the pore size. When the dust sinks on the surface of the filter material and the pores of the filter material become small, the particles with small size cannot pass through the pores and thus get trapped. With the formation and thickening of the dust layer, the screening efficiency will be significantly improved.
3 粉尘层对尘粒的捕集
3.1 Dust layer traps dust particles
如前所述,过滤操作一定时间后,由于粘附等作用,尘粒在滤料网孔间产生架桥现象,使气流通过滤料的孔径变得很小,从而使滤料网孔及其表面迅速截留粉尘形成粉尘层,当清灰后依照残留一定厚度的粉尘,称为粉尘初层。由于粉尘初层中粉尘粒径通常都比纤维小,因此筛滤、惯性、截留和扩散等作用都有所增加,使除尘效率显著提高。由此可见,袋式尘器的高效率,粉尘初层起着比滤料本身更为重要的作用,一般合成纤维布的网孔为20-50m,如为起毛的则为5-10 m,用这样的滤料,只要设计得当,***是0.1pm的尘粒也能获得将近****的除尘效率。
当滤袋表面积积附的粉尘层厚到一定程度时,需要对滤袋进行清灰,以******滤袋持续工作所需的透气性。袋式除尘器正是在这种不断滤尘而又不断清灰的交替过程中进行工作的。
3 粉尘层对尘粒的捕集
3.1 Dust layer traps dust particles
As mentioned above, after a certain time of filtration operation, due to adhesion and other effects, dust particles will bridge between the filter mesh, making the pore diameter of the filter material in air circulation become very small, so that the filter mesh and its surface can quickly intercept dust to form a dust layer. When the dust is cleaned, according to the residual dust of a certain thickness, it is called the initial dust layer. Since the particle size of dust in the initial layer of dust is usually smaller than that of the fiber, screening, inertia, interception and diffusion are all increased, which significantly improves the dust removal efficiency. It can be seen that the high efficiency of the bag filter, dust primary layer plays a more important role than the filter itself. Generally speaking, the mesh of synthetic fiber cloth is 20-50m, and if it is fluffiness, it is 5-10um. With such filter material, as long as it is properly designed, the dust particle of 0.1um can achieve nearly **** dust removal efficiency.
When the dust layer accumulated on the surface area of the filter bag is thick enough, it is necessary to clean the filter bag to ensure the air permeability required by the continuous work of the filter bag. It is in this alternating process of continuous dust filtering and continuous dust removal that the bag filter works.