Description of external and internal filtration of dust bag
It shall be combined with corresponding accessories to keep the shape suitable for filtering and ash removal during filtering and ash removal, complete the purpose of filtering or stripping dust particles, and keep the dust collector in normal operation. The combination of filter bag and accessories is called filter unit.
There are two types of accessories for the internal and external filter units.
(1) Accessories sewn together with the filter bag. Such accessories need to be sewn on the filter bag during the process of sewing the filter bag. Such as the elastic ring at the mouth of the outer filter bag and the anti-collapse ring of the inner filter bag.
(2) Accessories used to support or hang filter bags. Such accessories are not sewn together with the filter bag. When the filter bag is installed on the dust collector, it is necessary to install it together. Such as the structure of the outer filter bag and the hanging equipment of the inner filter bag.
A.Accessories of dust filter bag external filter unit
(1) Accessories sewn together with the filter bag – bag mouth elastic ring.
The mouth of the external filter bag is fixed on the perforated plate and should be firmly sealed. Since the gas entering the porous plate has been purified, if there is leakage at the filter bag installed on the porous plate, the dusty air flow will enter the clean air chamber, and the dust removal efficiency of the dust collector will be greatly reduced. There are two key points for sealing the filter bag mouth and porous plate. The processing of each hole on the main perforated plate shall meet the requirements, the size of all holes shall be consistent, and the accuracy shall be controlled within the range of minus 0 + 0.3mm. Second, if the material of the elastic ring at the bag mouth is stainless steel or spring steel with excellent elasticity, the steel strip with thickness of 0.3 ~ 0.5 mm shall be selected according to the diameter of the bag mouth. After the elastic ring is made, the fillets suitable for the thickness of the perforated plate shall also be pasted. The same kind of filter material of the filter bag is selected as the material of the fillets. Generally, the leftover material of the same kind of filter material is used. When sewing the external filter bag, the elastic ring shall be sewn on the upper mouth of the filter bag.
The size of the filter bag opening with elastic ring on the inspection seam cannot be measured with a measuring tool. The orifice plate (the aperture of the orifice plate is the aperture of the perforated plate) shall be used for inspection.
(2) Accessories supporting filter bag – filter bag structure
The structure of the dust removal bag is used to support the filter bag so that it is in a tensioned state during the filtration and ash removal process, and maintain a shape conducive to filtration and ash removal. From this point of view, the structure is the “rib” of the filter bag, which should be light and convenient for installation and maintenance. In particular, it should be smooth, straight and free of burrs, so that the filter bag is not damaged.
The shape of the structure of the filter bag is consistent with the type of the filter bag. The round filter bag is equipped with the round structure, the flat bag is equipped with the flat structure, and the envelope bag is equipped with the envelope structure.
Filter bag and structure and cooperation: the synthetic fiber filter bag and structure shall be loose cooperation. The diameter and length of the filter bag shall be greater than the diameter and length of the structure, and the spacing between the vertical bars of the structure shall be less than or equal to 40mm. The glass fiber filter bag and the structure shall be close cooperation. The diameter and length of the filter bag shall be equal to the diameter and length of the structure, and the spacing between the vertical bars of the structure shall be less than or equal to 20mm.
The vertical reinforcement of the structure shall be selected according to the different length of the structure φ 3~ φ 3.5 carbon steel. The surface shall be subject to corresponding anti-corrosion treatment. If necessary, stainless steel materials shall be selected for manufacturing.
In addition to the structure, the accessories used for the external filter unit include filter bag seat and Venturi tube. In our country, gas cutting is a relatively backward process for processing porous plates in many dust collector main machine factories. In particular, some small and porous plates in the early stage were mostly gas cut. The size is forbidden and rough. An aluminum die-casting filter bag seat is often used in the reconstruction of these dust collectors. So that each hole on the perforated plate can fit the filter bag with elastic ring mouth. Convenient for installation and maintenance. And is conducive to the reliable sealing between the filter bag and the porous plate.