Carpenter's circular spiral air duct

Strictly speaking, the so-called spiral duct is a type of duct processing technology, also known as spiral seam thin-walled pipe. It is a thin-walled pipe made of metal strip material rolled into a spiral seam shape. Due to the use of metal as the material, it is also known as spiral seam metal pipe. It was first applied in the military industry of Western countries, such as ships, ship ventilation, and air conditioning systems, and later used in civilian facilities such as trains, subways, and mines. By the year 2000, according to statistics, the use of spiral ducts in office buildings, shopping malls, subways, and other areas in the United States had reached 95.6%. The proportion of spiral air ducts used in central air conditioning in residential buildings also reaches 72.5%. China began to introduce this technology for the shipbuilding industry in the mid-1990s. With the rapid development of the Chinese economy, the use of central air conditioning has been increasing year by year, and the quality of exhaust and supply products has been continuously improving. Spiral ducts have been used first in some foreign-funded and joint venture enterprises. The characteristics of spiral air duct, such as no welding, no air leakage, no water leakage, low noise, small ventilation resistance, low cost, solid, beautiful, etc., are gradually recognized by countrymen people. Therefore, the application of spiral ducts has been widely popularized.