1 Duct seams
a: L = 3m, longitudinal seams no more than 1;
L = 5m ,longitudinal seams no more than 4;
L = 10m ,longitudinal seams no more than 2.
b: D = 300,400,500 mm, the circumferential seams more than 2;
D = 600,800,1000 circle seams no more than 3.
2 Flange length: L1=150mm,L2=200mm.
3.The bending deformation of the end ring is less than or equal to 1.2% of the original diameter, the end of the section to the duct ring line is not perpendicular of not more than 4
a: Rings of both end ,at the site that 200mm away form end ring , install ring at the intersection of the duct inner circumferential seams and duct inner ring layering, the spacing is 2 times section distance (300mm). Rings should be securely installed, seamless.
b: L = 3 m or 5 m, the rings mounted reversing duct does not exceed 1/24th of ram circumference,L = 10 m, the amount of twist rings mounted to ram circumference does not exceed 1/16.
a: air duct drag per kilometers, air leakage rate per kilometers meets Table 3 requirement
Duct diameter Drag per 100m leakage rate per100m
mm N S2/m8 o %
300 ≤1728.0 ≤5.0
400 ≤410. 0
b: resistance to negative pressure in Table 4, the test does not produce negative pressure resistant duct disjointed, coated cloth tear, and the inner pressure of the separation, the joint opening and other anomalies. Duct diameter shrinkage in accordance with Table 4 provides:
Duct diameter mm pitch mm negative resistance Pa duct diameter shrinkage%
300～500 150 ≥4500 5
600～800 100 ≥4000 3
7 coated cloth duct meet MT383-1995 standard.
Due to production batch, the specific model, the above pictures for reference only, you can contact our sales staff to verify the specific