The connection methods for PVC pipes mainly include three types:rubber gasket connection,solvent cement bonding,and flange connection. Pipes with a diameter of ≥100 mm generally adopt rubber gasket joints; those with a diameter of <100 mm typically use solvent cement bonded joints, while some use union joints.When pipes cross sewers or other pipelines, metal pipes are usually employed, and in such cases,the connection between plastic pipes and metal pipes is achieved via flange connection.The connections between valves and adjacent pipes also utilize flange connection.
1.When solvent cement bonding is applied for small-diameter pipes,the spigot end must be chamfered to form a bevel.Ensure the fracture is flat and perpendicular to the pipe axis to achieve a secure bond and prevent water leakage.
2.Generally,PVC pipes with a diameter of ≥100 mm use rubber gasket joints. Before installation,personnel must chamfer the spigot end of the pipe and inspect the rubber gasket for qualified quality.During installation, the socket, rubber gasket,and other components must be thoroughly cleaned.
3.For traditional pipeline installation,the trench excavation only requires sufficient space to place the pipe and perform backfilling.If the original soil layer remains undisturbed, compaction of the bedding layer may be omitted.
4.For branching of PVC pipe branches,tees or vertical stop cocks can be used. During construction,a saddle-shaped fitting (half a split tee) can be installed and secured with U-bolts to reinforce the pipe wall.Subsequently,a hole can be drilled directly on the fitting for threading,followed by connecting external threaded plastic components.Tests have shown that the pressure test acceptance after construction using this method fully meets the requirements of relevant specifications. Additionally,thrust blocks should be installed at locations where water flow generates thrust,such as elbows, tees, and pipe end closures, to withstand the hydraulic thrust.
5.As a new type of non-metallic pipe, the exact location of PVC pipes cannot be detected by existing metal pipeline detection equipment. However,this problem can be conveniently solved by burying a wire above the pipe during the pipe laying construction.