Bag filter is a dry dust filtering device. It is suitable for capturing small, dry, non fibrous dust. The filter bag is made of textile filter cloth or non-woven felt, and uses the filtering effect of fiber fabric to filter the dust containing gas. When the dust containing gas enters the bag filter, the large and heavy dust particles settle down due to gravity and fall into the ash hopper. When the gas containing finer and smaller dust passes through the filter material, the dust is retained and the gas is purified.

Basic Introduction

Bag filter is a dry dust filtering device. After using the filter material for a period of time, due to screening, collision, retention, diffusion, static electricity and other effects, a layer of dust accumulates on the surface of the filter bag, which is called the initial layer. During the subsequent movement process, the initial layer becomes the main filtering layer of the filter material. With the help of the initial layer, filter materials with larger mesh holes can also achieve higher filtration efficiency. As dust accumulates on the surface of the filter material, the efficiency and resistance of the dust collector increase accordingly. When the pressure difference between the two sides of the filter material is large, some small dust particles that have already adhered to the filter material will be squeezed out, causing a decrease in the efficiency of the dust collector. In addition, excessive resistance of the dust collector can significantly reduce the airflow of the dust removal system. Therefore, after the resistance of the dust collector reaches a certain value, it is necessary to clean the dust in a timely manner. When cleaning, the initial layer should not be damaged to avoid a decrease in efficiency.

Structure diagram of bag filter:

The structure of a bag filter mainly consists of an upper box, a middle box, a lower box (ash hopper), a cleaning system, and an ash discharge mechanism.

Filter materials are made of fibers, including cotton fibers, wool fibers, synthetic fibers, and glass fibers. Filter materials woven from different fibers have different properties. The commonly used filter materials include 208 or 901 polyester velvet cloth, which is generally used at a temperature not exceeding 120 ℃. Glass fiber filter bags treated with silicone resin are generally used at a temperature not exceeding 250 ℃. Cotton wool fabrics are generally suitable for non corrosive applications; Dust containing gas with a temperature below 80-90 ℃.
Main features
⑴ The dust removal efficiency is high, generally above 99%. The dust concentration in the outlet gas of the dust collector is within tens of mg/m3, and it has a high classification efficiency for fine dust with sub micron particle size.

⑵ The range of air volume processing is wide, ranging from only a few cubic meters per minute to tens of thousands of cubic meters per minute. It is used for dust removal of flue gas in industrial furnaces and kilns, reducing the emission of atmospheric pollutants.

⑶ Simple structure, easy maintenance and operation.

On the premise of ensuring the same high dust removal efficiency, the cost is lower than that of electrostatic precipitators.

When using high-temperature resistant filter media such as glass fiber, polytetrafluoroethylene, P84, etc., it can operate under high temperature conditions above 200 ℃.

(6) Not sensitive to the characteristics of dust and not affected by dust and resistance.