The connection methods of UPVC water pipe mainly include sealing rubber ring, bonding and flange connection. A pipe diameter greater than or equal to 100mm generally uses a rubber ring interface. Pipes with a diameter of less than 100mm generally use adhesive joints and some use live joints. Metal pipes can generally be used when crossing sewers or other pipes. This is a plastic pipe, and a metal pipe is connected with flanges.The connection between the front and back of the valve and the pipeline is also made of flange connection.

1 · When the small diameter pipe is bonded with solvent, the socket must be turned into a small rounded corner to form a groove and ensure that the fracture is smooth and vertical axis so that the bonding can be firm to avoid water leakage. Some manufacturers do not mark the insertion line at the socket of the plastic pipe. In view of this situation, personnel must be arranged to mark the insertion line at the insertion depth before on-site construction. Because the UPVC pipeline has the characteristics of large expansion coefficient, it must be set every certain distance (about 30m is often used in actual construction), or the method of first bonding a certain length and then changing the rubber ring interface to compensate for the expansion.

2∙ Generally, UPVC pipes with a diameter greater than or equal to 100mm are equipped with rubber ring interfaces. Before installation, personnel must be arranged to chamfer the pipe socket and check whether the quality of the rubber ring is qualified. During installation, the socket and rubber ring must be wiped clean. When inserting the socket, the socket must be inserted in the direction of the pipe axis and cannot be tilted. Otherwise, the top of the rubber ring will cause different degrees of displacement of the rubber ring and water leakage. In case of incomplete pipe distribution during construction, when the UPVC pipe is connected to the steel pipe, the steel pipe can be welded into a socket, but the length of the socket must be greater than 20cm. During installation, the UPVC pipe must be inserted into the root of the socket of the steel pipe, and the UPVC pipe in the inserted part must be chised and ground. Then, the expansion cement can be used to make a hole.

3∙ Trench excavation of traditional pipeline installation only requires that the pipe can be placed into the trench and sealed so that the pressure tamping pad is not required when the original soil layer is not loosened. The bottom of the pipe trench of the UPVC pipe requires the backfilling of 10cm thick sand without hard objects. The side and above of the pipe require the backfilling of sand without hard objects (especially hard objects with sharp angles). The thickness of the sand layer above the pipe should reach 20 ~ 30cm and then put the backfilling soil. Backfill requires layered backfill to ensure the density of the soil at the bottom and side of the pipe so as to prevent deformation, interface damage, and water leakage caused by uneven force on the pipe.

4∙ The fork of the general UPVC pipe branch can be opened by a three-way or vertical water stop. During construction, a saddle-shaped fitting (half a two-tee) can be added, and a U-shaped bolt is clamped so that the pipe wall is thickened, and then the drilling teeth are drilled directly on it, and then the plastic parts are threaded out. The test shows that this method can be used for pressure tests and acceptance after construction

To meet the requirements of the code. In addition, thrust piers should be set at the places where the water in the pipe generates thrust, such as elbows, tees and the sealing plates at the end of the pipe, to withstand the thrust of the water.

5 · UPVC pipe is a new type of non-metallic pipe; the existing metal pipe detection equipment can not detect its specific location, but if the pipe is buried during construction, burying a wire above the pipe can easily solve this problem.We choose 4mm green plastic leather single copper core wire when the pipe diameter DN is ≥90; 2∙5mm green plastic leather single copper core wire when the pipe diameter DN is ≤60mm. (The connection of metal wires should be handled in the way that electrical wires are stranded. The length of the stranded part should not be less than 0∙8m To prevent premature oxidation of the joint).

6∙ According to the leakage situation, UPVC pipe repair can be repaired by pipe change, sleeve repair, fiberglass method and welding: ① The whole section of the pipe needs to be replaced if the pipe is damaged in a large area, the method of connecting and replacing the pipe can be double socket (live pipe fitting). During the construction of this method, it should be noted that the insert pipe end should be chamfered to form a groove, the insert pipe end of the original pipe segment, and the replacement pipe should be marked with the insert length mark. The bushing bonding method is mainly for the perforation of small holes and leakage of joints in pipelines. Select a pipe of the same caliber about 15 ~ 20cm long and cut it longitudinally according to the procedure of bonding joint; the inner surface of the casing and the surface of the repaired pipe are coated with wool and glue, and then put it on the water leakage. ③ FRP method uses epoxy resin and a curing agent to prepare a resin solution with glass fiber soaked in resin solution and then evenly wound in the pipeline or joint leakage

The place can be solidified into fiberglass steel to stop the water and fill the leak. If possible, a stainless steel clamp can also be added at the leak point to clamp the glass fiber cloth. UPVC pipes have many characteristics that are not found in metal feed pipes. It is resistant to corrosion, does not scale, can inhibit the growth of bacteria, and can effectively prevent secondary pollution in the pipeline. If the pipeline is connected by the rubber ring flexible socket, its vibration resistance and sealing performance are better, which can effectively prevent leakage. The use of this kind of pipe in water supply engineering can not only facilitate construction and reduce project costs but also help to ensure water quality, save operating costs, and reduce production costs.