As early as the 1970s, cartridge filter dust collector has appeared in Japan and some European and American countries. It has the advantages of small volume, high efficiency, low investment and easy maintenance. However, due to its small equipment capacity, it is difficult to combine into large air volume equipment, low filtering wind speed and narrow application range, it is only used in grain, welding and other industries, so it has not been widely promoted for many years. In recent years, with the continuous development of new technologies and materials, companies in Japan and the United States, as representatives, have improved the structure and filter material of the dust collector, making the cartridge filter widely used in cement, steel, electric power, food, metallurgy, chemical industry and other industrial fields. The overall capacity has increased several times. It has become a large dust collector (gb6719-86) with a filter area of >2000m2, which is a solution to the difficulty of collecting ultra-fine dust by traditional dust collectors The best scheme with high filtering wind speed, poor ash removal effect, easy wear and leakage of filter bags and high operation cost has the characteristics of large effective filtering area, low pressure difference, low emission, small volume and long service life compared with the existing bag type and electrostatic precipitators in the market, which has become a new direction for the development of industrial precipitators.
After the dusty gas enters the ash hopper of the dust collector, due to the sudden expansion of the air flow section and the action of the air flow distribution plate, part of the coarse particles in the air flow settle in the ash hopper under the action of dynamic and inertial forces; After the fine particle size and small density dust particles enter the dust filter chamber, the dust is deposited on the surface of the filter material through the combined effects of Brownian diffusion and screen filtration. The purified gas enters the air purification chamber and is discharged by the exhaust pipe through the fan.
The resistance of the cartridge filter increases with the increase of the thickness of the dust layer on the surface of the filter material. The ash shall be removed when the resistance reaches a specified value. At this time, the PLC program controls the opening and closing of the pulse valve. First, the lift valve of the first compartment is closed to cut off the filtered air flow, and then the electromagnetic pulse valve is opened. The compressed air expands rapidly in the upper tank and flows into the filter cartridge in a short time, causing the expansion and deformation of the filter cartridge to produce vibration. Under the action of reverse air flow scouring, the dust attached to the outer surface of the filter bag is stripped off and falls into the ash hopper. After the ash cleaning, the electromagnetic pulse valve is closed, the poppet valve is opened, and the chamber is restored to the filtering state. Each room shall be cleaned in turn. The period from the first room to the next one is a cleaning cycle. The fallen dust falls into the ash hopper and is discharged through the ash unloading valve.
During this process, the filter cartridge must be replaced and cleaned regularly to ensure the filtering effect and accuracy. In addition to being blocked, some dust will be deposited on the surface of the filter material during the filtering process, increasing the resistance. Therefore, the general correct replacement time is three to five months