Psp steel-plastic composite pipe is a pipe with welded steel pipe as the middle layer, polyethylene plastic as the inner and outer layers, and special hot melt adhesive, which is compounded into one by extrusion molding. The English name is plastic-steel composite pressure pipe, or PSP pipe for short.
PSP steel-plastic composite pressure pipe is divided into flared connection, double hot-melt transition connection and intelligent electromagnetic induction double hot-melt connection, in which intelligent electromagnetic induction double hot-melt connection is referred to as "electromagnetic connection" and "e-PSP steel-plastic composite pressure pipe".
Second, the performance characteristics of psp steel-plastic pipe
1. The complete steel pipe layer is the main bearing layer of the pipe body, so the bearing capacity of the pipe is not affected by the performance change of the plastic layer.
2. Compared with plastic pipe, it has higher strength, rigidity and impact resistance, low expansion coefficient and creep resistance similar to steel pipe, and its tensile strength is 7-8 times that of pure plastic pipe. The external pressure that buried pipes can bear is much higher than that of pure plastic pipes.
3. self-tracking. Because the middle steel pipe layer is a complete pressure-bearing layer, it can be tracked by magnetic metal detector, and there is no need to bury additional tracking or protection marks, which can avoid excavation damage and provide great convenience for emergency maintenance.
4, strong anti-corrosion ability. Both internal and external plastics are PE, which is insoluble in any solvent and has stable chemical properties. At normal temperature, it can resist the corrosion of various acid, alkali and salt solutions. When the pipeline is buried, it is not necessary to take additional anti-corrosion measures for the pipeline. When installing GB50268, only local anti-corrosion measures are needed for flange joints, which saves a lot of installation time and cost.
5. Flared pipe fittings and double hot-melt crimping pipe fittings correspond to the size and caliber respectively, which have excellent sealing performance, anti-dropping, convenient installation and adapt to the deformation of various pipes and pipelines.
6. It has certain flexibility and can be bent, so the adaptability of decoration, transportation and installation and the reliability of operation are high. Underground installation can effectively withstand the sudden impact load caused by settlement, sliding and vehicles. A single steel-plastic composite pressure pipe with a fixed length (12m) can be bent 25 in one direction, which saves the amount of small-angle steering elbow.
7. The roughness of the inner wall of the pipeline is 0.007mm, the pipe wall is smooth, the fluid resistance is small, and there is no scaling. Under the same pipe diameter and pressure, the head loss is 30% lower than that of metal pipe, and a larger conveying flow can be obtained. The structure integrates rigidity and flexibility, and can quickly eliminate the pressure impact in the pipeline system without water hammer noise.
8. The pipe product standard requires compound GB/T 17 129 standard, which is hygienic and non-toxic and can be used for direct drinking water transportation.
9. Low linear expansion coefficient. The linear expansion coefficient of the pipeline is 1.2x 10-/℃, which is110 ~1/2 of pure plastic pipe.
10, long service life. It can be used for 50 years at normal temperature and pressure.
1 1, good insulation. The breakdown voltage of polyethylene material is more than 20KV/mm, and the plastic thickness of steel-plastic composite pressure pipe is1.6-5.5mm. As a cable protection sleeve, the middle steel pipe has strength and the internal and external materials are well insulated. By adopting high-precision sealing technology, the end face of the steel-plastic composite pressure pipe is completely wrapped by polyethylene plastic, and the pressure-bearing layer of the middle steel belt is not in contact with air and other media, so the overall anti-corrosion effect is not affected by the end face, and the thermal insulation performance of the whole pipe is equivalent to that of a pure plastic pipe. For the urban power grid, the electrical insulation performance of psp protective sleeve is greater than that of power cable, so it will be safer to use.
Third, the application field of psp steel-plastic composite pipe
1, construction, municipal water supply project
Good pressure-bearing performance, water hammer resistance and high mechanical connection reliability, suitable for the harsh environment of the construction site, and suitable for the water supply pipeline of public buildings and houses. The material has long service life, and can be used to detect pipeline laying lines when buried, which is convenient for municipal engineering.
2. Central heating system
The internal and external plastics are steel-plastic composite pressure pipes made of high-temperature resistant polyethylene or crosslinked polyethylene, which can transport 70℃ fluid medium for a long time and 95℃ fluid medium instantly.
3. Special fluid piping system
It has good chemical stability. It is connected by mechanized chemical patented pipe fittings, and the part in contact with the conveying medium is made of corrosion-resistant plastic whose bottom thickness is not less than the plastic layer in the steel-plastic composite pressure pipe. The mechanical strength of the anticorrosion coating of pipe fittings is greater than that of pipe fittings, so the corrosion resistance of pipe fittings is not lower than that of pipe fittings, and the connection is reliable. Can be widely used in petroleum, chemical, pharmaceutical, food, mining and other fields.
4, communication, power cable protection sleeve system
The closed steel strip layer in steel-plastic composite pressure pipe can effectively shield external electromagnetic interference, and is suitable for communication line protection sleeve pipeline system. The antistatic flame-retardant steel-plastic sheath made of special polyethylene material has a breakdown voltage greater than 20KV/mm and high ring stiffness, which can be widely used in power cables, highways, industrial buildings and other fields.