What are the types of bag dust collector bags How to choose bag dust collector bags

1. What are the types of bag filters?

1. According to the temperature material distribution bag dust collector bag can be divided into three types according to the temperature material: normal temperature dust bag, medium temperature dust bag and high temperature dust bag. (1) Normal temperature cloth bag Normal temperature cloth bag is mainly made of polyester, polypropylene, acrylic and other fibers through non-woven and textile processes. It has excellent performance such as good air permeability, smooth surface, good dimensional stability, and easy dust removal. It is mainly used in the fields of dust removal and normal temperature flue gas treatment in industries with dust pollution in general industrial enterprises. (2) With the country's increasing emphasis on environmental protection, especially the rapid development of the bag dust removal technology industry in recent years, China has begun to use imported synthetic fibers to develop products that can adapt to harsher working conditions and can be used for a long time. Long-life high-performance filter material. The more common medium-temperature filter materials are aramid fibers and PPS series fibers, which are treated by impregnation, waterproof, oil-proof, and anti-corrosion processes to achieve ideal results. (3) High-temperature cloth bags High-temperature cloth bags are mainly made of high-temperature-resistant fibers such as P84, expanded glass fiber, and ultra-fine glass fiber through textile and non-woven processes. They have the characteristics of good thermal stability, high filtration efficiency, and long service life. It is mainly used in dust collectors under various high-temperature flue gas conditions; DWD high-temperature cloth bags are used for parts with harsh working conditions, and polyester cloth bags are used for ordinary dust collection parts.

2. According to the shape, the shape of the dust bag is mainly divided into three types: round, flat and special. (1) Round: The dust bag is cylindrical. Its specifications are represented by diameter × length, that is, D × L (mm). (2) Flat shape: The dust collector bag is flat, including rectangles and trapezoids, and its specifications are expressed by perimeter x length, that is, P x L (mm). (3) Abnormal shape: a filter bag with a specific shape, the specification is expressed by the characteristic parameters of its structure.

  3. According to the filtration method, there are two main types of filtration method: inner filter type and outer filter type. (1) Inner filter dust bag: After the dust-containing gas is filtered through the inner surface of the dust filter bag, the dust is blocked on the inner surface of the filter bag. This filtering method is called inner filter. (2) External filter filter bag: When the dust-laden gas is filtered through the outer surface of the dust filter bag, the dust is blocked on the outer surface of the filter bag. This filtering method is called the outer filter type.

2. How to choose the bag for the bag filter The selection of the bag for dust removal is very important, it directly affects the dust removal effect of the filter. The method of correctly selecting the dust collector bag includes: selecting temperature, humidity, corrosiveness, dust shape, flammability and explosiveness according to the physical and chemical characteristics of the dust-containing gas, selecting the cleaning method of the bag filter, and so on.

1. Temperature of dusty gas The temperature of dusty gas discharged from the mixture mixer is an important factor for the correct selection of filter cloth for bag filter. According to the temperature of continuous use, the dust bag can be divided into three types: normal temperature bag (less than 130°C), medium temperature bag (130-200°C) and high temperature bag (greater than 200°C). For working conditions where the dusty gas temperature fluctuates greatly, the selection coefficient should be slightly larger, but the instantaneous peak temperature cannot exceed the upper limit temperature of the bag. For the high-temperature dust-laden gas discharged from the mixing machine, high-temperature cloth bags can be directly used.

2. Humidity of dust-laden gas The humidity of dust-laden gas is another important factor for the correct selection of bags for the bag filter of the mixture mixer. The humidity of the dust-laden gas indicates the degree of water vapor contained in the gas, usually expressed by the water vapor volume percentage Xw or the relative humidity fraction Xw or relative humidity ψ in the dust-laden gas. When Xw is greater than 8%, or less than 80%, it is called wet dusty gas. For the wet dusty gas, the following points should be paid attention to when selecting the bag: 1) The wet dusty gas makes the dust captured on the surface of the bag wet and bonded, and it may even cause the bag to stick to the water-absorbing and deliquescent dust. For this reason, filter cloths with smooth surface and easy-to-clean fiber materials such as nylon and glass fiber should be selected, and silicone oil and carbon should be used for filter cloth. fluorine. Resin impregnation treatment, or coating treatment with acrylic acid, polytetrafluoroethylene, fluorine, vinyl, etc. on the surface of the filter cloth. 2) When high temperature and high humidity are present in the flue gas discharged from the mixture mixer, it will affect the temperature resistance of the filter cloth, which is the case for materials with poor hydrolytic stability such as polyamide, polyester, and imide. Therefore, the bag filter should be carefully selected for maintenance (replacement of filter bags), and the water content of the cold aggregate (≤3%) should be strictly controlled during the production process of the mixer.

3. Corrosivity of dusty gas Different fibers have different chemical properties and are often affected by various factors such as temperature and humidity. 4. Select the cloth bag according to the properties of the dust. The properties of the dust include the chemical and physical properties of the dust. Now focus on the correct selection of the material, structure and post-treatment of the filter cloth from the physical properties of the dust. 5. The shape and particle size distribution of dust Generally, the products of high-temperature combustion process are mostly regular-shaped dust, while the dust particles produced by most processes are mostly irregular. Regular dust has smooth surface and small specific surface area, so it is not easy to be intercepted and condensed when passing through the bag; on the contrary, irregular dust has different shapes, rough surface and large specific surface area, so it is easy to be intercepted and condensed when passing through the bag. The following points should be paid attention to when choosing a bag filter for the bag filter: 1) The fiber should be thinner, shorter, curly, and irregular in cross-section. 2) Needle-punched felt is the best structure. If the fabric is used, it should be twill weave or brushed on the surface. 3) Needle-punched felt with a density gradient should be used when the thickness of the mixed cotton layer is used, and surface filtration through surface spraying, impregnation or coating, etc., is the development direction of dust selection filter cloth. 4) Fine particle dust is difficult to capture and it is easy to form a dense dust layer after capture, which is not conducive to dust removal. On the contrary, coarse particle dust is easy to capture, and the dust layer formed after capture is relatively loose, which is conducive to dust removal. In a sense, dust with a fine and fine thickness is beneficial to both filtration and dust removal.