Taking all factors into consideration, in most cases, the space occupied by a circular tube is smaller than that of a rectangular tube. Pipe diameter: φ 125 ~φ 1500mm (appropriate matching of diameter and thickness), stepless selection. The ventilation duct installation of general dust removal system in spiral duct should be carried out when the process equipment related to air duct is installed in the workshop and the position of equipment nozzle or dust hood is fixed. Structure: Material: galvanized iron belt (commonly known as Xingtie), stainless steel belt and soft aluminum belt. Material: 0.3 to1.2mm. Material:125mm. Spiral duct has the advantages of excellent performance and low cost since it was put on the market. Therefore, its application in ventilation and air conditioning system has been continuously promoted. Maintenance method: ventilation engineering cost reduction method: Because there are bones (spiral bite) in spiral duct that can increase the strength by 30%, thinner materials can be selected, for example, the thickness of 0.8mm can be changed to 0.6mm, and all kinds of ventilation pipes, components and fittings composed of ventilation and air conditioning system pipes have been processed and passed the quality inspection. Since we know that the primary task of enterprises in the economic crisis is to survive, enterprises need to adjust their business structure, compress or cut off businesses with low profitability, so as to concentrate their resources on businesses that can be cashed immediately. For the same pressure characteristics, the installation space of several circular pipes is often the same as or smaller than that of a rectangular pipe. This method requires that the air duct should have a large manhole for operators to enter and exit, but this method is most likely to miss some dust and dirt, because the air duct can not form a complete negative pressure state. Bulk material transportation: in the production process of some factories, it is necessary to transport loose particles, especially particles with small specific gravity such as foam plastic particles. Spiral catheter has low cost and good effect. Spiral duct mainly coats a layer of zinc on the iron sheet of the air duct to protect the iron sheet. After passivation treatment, dyeing or coating with photo-protective agent, the protective and decorative properties of zinc coating can be significantly improved. High quality moisture-proof and waterproof, light weight, low cost, convenient installation, beautiful and applicable. It is a full-mechanism air duct, and the straight pipe does not need to be knocked by hand. Under the same cross-sectional area, the circumference of rectangular air duct with the length-width ratio of 1:3 is 40% longer than that of spiral duct, saving materials; Similarly, due to the length of spiral duct week, the thermal insulation materials can be reduced accordingly. Generally speaking, the flow of ventilation system is very large. Therefore, it is required to use low-resistance air conveying pipeline to save manufacturing cost and operating cost, so spiral duct is the best choice. In bulk material conveying: pneumatic conveying system, some fine and loose material particles can be conveyed through spiral conduit, with low cost and good effect. Gas flushing: this method uses a hose with a nozzle to connect to the air duct to transport compressed air. The nozzle is designed so that compressed air can drive dust and dirt in. Only by taking good care of the air duct can we extend the "life". Of course, the best maintenance method is to clean the air duct regularly. There are three most effective ways to clean the air duct: vacuum suction: operating with a vacuum straw similar to a hand. Direct contact with the inner wall of the pipeline with a brush to remove dirt. Composite spiral duct is generally used in places where the external environment is general and the requirements for air ducts are not too high. The most widely circulated spiral duct in the market is galvanized sheet. Galvanized spiral duct is basically the characteristic of stainless steel spiral duct, but its price is only two-thirds or even lower than that of stainless steel duct.