DN1080 waterproof casing flexible waterproof casing rigid waterproof casing

Rigid waterproof casing describes that water supply and drainage plastic pipes can be roughly divided into four categories according to the load they bear during use
① Pipes and fittings that bear internal pressure, such as building water supply pipes, etc.
② Those that bear external pressure loads Pipes and fittings such as buried drainage pipes, buried cables, optical cable sheathing pipes
③ Pipes and fittings that basically do not withstand internal pressure or external pressure, such as drainage pipes and rainwater pipes in buildings
④ Simultaneously withstand internal pressure And pipes and fittings with external pressure load, such as underground water supply pipes, underground gas pipes, etc.
When pipes and fittings are subjected to internal pressure loads, uniform tensile stress is generated in the pipe wall. The main consideration in design is strength, which should be designed based on its long-term creep resistance strength. If the strength is not sufficient, the pipe and fittings will break.
When pipes and fittings are subjected to external pressure loads, the stress generated in the pipe wall is relatively complex. When the burial conditions are relatively good, due to the joint action of the pipe and soil, the pipe wall mainly bears compressive stress. When the burial conditions are relatively poor, Bending moments are generated in the pipe wall, and some inner and outer walls bear large compressive stress or tensile stress. The main consideration during design is the hoop stiffness. If the circumferential stiffness is not enough, the pipes and fittings will undergo excessive deformation, causing leakage at the connections or causing the pipe wall to collapse and bend inward.