In the double-wall bellows, SN represents the ring stiffness, SN4 represents 4 dry cows per square meter, and SN8 represents 8 thousand cows per square meter, which is a value for evaluating the ring stiffness, and is also a grade division of the pipe, representing the force it bears. This means that each square meter is subjected to external pressure greater than or equal to 4 or 8 thousand cows. There are two ways to express the change stiffness, one is that S1 and S2 represent class 4 and 8 respectively, and the other is that SN4 and SN8 represent class 4 and 8 respectively.
The SN4 ring stiffness is that the buried depth of 4000kN can not exceed 1.5 meters under normal construction, and the pressure resistance of SN4 is less than that of SN8. The SN8 ring stiffness means that the pressure resistance of 8000kN is stronger, and the average buried depth can reach less than 3.5 meters.
How to distinguish the appearance of SN4 and SN8 tubes
The appearance of the SN4 tube crest is shorter, the inner wall thickness is relatively thin, and the weight of each tube is much lighter than that of SN8, the appearance of the SN8 tube crest is higher, the inner wall thickness is relatively thicker, and the weight of each tube is heavier than that of SN4, and the appearance is the same.
Application range of double wall bellows
1, municipal engineering: used as drainage, sewage pipe.
2, construction engineering: used as building rainwater pipe, underground drainage pipe, sewage pipe, ventilation pipe.
3, railway, highway communication equipment: used as a communication cable, optical cable protection tube.
4, industry: widely used in chemical, hospital, environmental protection and other industries of sewage pipes.
5, agricultural garden project: used for farmland, fruit and tea gardens, and forest belt pipe.
6, road engineering: used as railway, highway infiltration, drainage pipe.
7, mine: used as mine ventilation, air supply, drainage pipe.
8, double-wall corrugated pipe with open holes: it can be used as the seepage and drainage pipe of saline highway.
9, golf course, football field project: used as a golf course, football field seepage, drainage pipe.