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Spiral duct

Spiral duct


Spiral duct            


Spiral ducts in the market are generally divided into three categories according to their materials: galvanized spiral ducts, stainless steel spiral ducts and composite spiral ducts. Among them, the stainless steel air duct has the best quality and strong applicability, but the price is high.

The most widely circulated spiral duct on the market is galvanized sheet. Galvanized spiral ducts are basically the characteristics of stainless steel spiral ducts, but the price is relatively only two-thirds or even lower than that of stainless steel ducts. Composite spiral ducts are generally used in places where the external environment is relatively common and the requirements for ducts are not too high.


Because the iron sheet is prone to chemical reactions in various environments, it can cause corrosion and rust. However, zinc hardly changes in dry air. In humid air, a dense basic zinc carbonate film will be formed on the surface of zinc. The spiral duct is mainly coated with a layer of zinc on the duct iron sheet, which protects the iron sheet. After the zinc coating is passivated, dyed or coated with a light protectant, its protective and decorative properties can be significantly improved.

Spiral duct has the following characteristics:

1. The appearance is smooth, free of zinc tumors and burrs, and is silvery white;

2. Easy installation and few connection points;

3. Low ventilation resistance and low ventilation noise;

4. Both strength and rigidity are good;

5. The thickness is all controllable and can be selected arbitrarily within 5-107μm;

6. No hydrogen embrittlement, no temperature hazard, which can ensure that the mechanical properties of the material remain unchanged;

7. It can replace some processes that require hot-dip galvanizing;

8. Good corrosion resistance, neutral salt spray test up to 240 hours;

9. It is completed by hot-dip galvanizing method, which is suitable for various strong acid, alkali mist and other strong corrosive environments;

10. Various specifications of air ducts can be specially designed and customized according to customer requirements.

Compared with hand-knocked traditional white iron pipes, machine-made spiral ducts have the following advantages:

(1) Good airtightness.

(2) Both strength and rigidity are good.

(3) The ventilation resistance is small, the ventilation noise is small, and the round pipe is better than the square pipe.

(4) Easy installation and few connection points.

(5) High-grade, beautiful appearance.

Main advantage

The installation of the spiral duct significantly reduces the connection points between the pipes and minimizes the leakage of the pipe joints. The typical spiral duct length is 3~6m, while the typical rectangular duct length is only 1 ~1.5m; and only one pipe connector is needed to connect two spiral ducts, while the connection of traditional rectangular ducts often requires a completely independent double flange system.

1. Standardized products

The production of spiral round duct fittings (pipe fittings and joints) has been highly automated, systematic, and has industrialized quality control.

2. Low installation cost

The installation time of the circular duct system is only 1/3 of the similar rectangular duct.

3. Usually only a small installation space is required

Without increasing any pressure drop, a round pipe with a diameter of 200mm in the same installation space can replace a rectangular pipe with a diameter of 250×150mm. Without adding additional installation space, several parallel circular pipes can replace flat rectangular pipes. Taking all factors into consideration, in most cases, the space occupied by circular pipes is less than that of rectangular pipes. For the same pressure characteristics, the installation space of several circular pipes is often the same or less than that of a rectangular pipe. Many rectangular piping systems require a 4-bolt system for installation, thus adding 40 to 80 mm in all directions of the piping.

4. Pressure drop: The wind resistance of a circular duct is much smaller than that of a rectangular duct.

5. Precise bite forming process: The molds used in the imported equipment are made of special steel structure. Even after three or five years of use, the surface of the pressing mold remains unchanged, so that the surface of the galvanized steel sheet is not damaged and greatly improved. The service life of the air duct is prolonged, while the seams are even and flat, the bite is tight, the connection force is strong, and the airtightness is good.

6. Safety seal ring leakage prevention system

7. The exquisite spiral pressing corrugated rib process makes the spiral duct have the best strength to withstand pressure. After the spiral corrugated rib is added, the thickness of the bite and lock seam is four times that of the pipe body. The rigidity of the pipe is very large, showing a firmness. Superiority, can withstand the maximum pressure load without destructive deformation, the thickness of the material can be reduced by 15%, and the cost can be reduced.

8. For the same cross-sectional area, the circumference of a rectangular duct with a length-to-width ratio of 1:3 is 40% longer than that of a spiral duct, which saves materials; in the same way, due to the short circumference of the spiral duct, the insulation materials can be reduced accordingly .

9. The pipeline layout is beautiful and the three-dimensional effect is strong: when the pipeline must be exposed as an architectural feature, the graceful and elegant formed flange air duct will be the best choice.

10. The installation form of the socket type spiral round duct.


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