Pvc fitting are used in construction, electricity and gas conduits, agricultural irrigation, industrial sewage and other projects. National PVC pipes have developed rapidly in recent years, with an annual growth rate of 8% and an annual demand growth rate of 2%. Among plastic pipes, the amount of PVC pipes has been far ahead, and it is widely used in water supply and drainage pipes. Due to the relatively mature technology, in recent years, PVC water supply pipes have not invested much in product innovation and relatively few new products. There are many ordinary products on the market, and there are few high-tech and high-value-added products.
Similar general-purpose products and medium and low-end products account for more Some, few high-end products. At present, the domestic production capacity of plastic pipes reaches 3 million tons, mainly including PVC, PE and PP-R pipes. Among them, PVC pipes have the largest market share, accounting for nearly 70% of plastic pipes. More than 1,600 PVC pipe production lines. The annual production capacity is more than 2.5 million tons. In 2003, the annual output of PVC pipes (pipe fittings) reached more than 1.2 million tons. In plastic pipes, PVC accounts for 70%, PE accounts for 25%, PP-R accounts for 4%, and others account for 1%. PVC pipe refers to the main raw material for pipes is PVC resin powder. The types of PVC pipes are generally classified according to the purpose of the pipes: drainage pipes, water supply pipes, wire pipes, cable sheaths.
Because the raw material formulations are different, the pressure resistance of various pipes and other aspects The indicators are not the same. PVC water supply pipes are used with water supply accessories for water supply projects in buildings. PVC drainage pipes are used for drainage and sewage. First, use sand paper to roughen the outside of the pvc pipe end and the inside of the socket of the pipe fitting, then use a clean rag to wipe off the polished lint, then apply glue evenly, and finally insert the pipe end into the socket of the pipe fitting. However, some construction workers did not use sandpaper at all during the construction process, or did not use a towel to clean the swarf after polishing, which left defects in the pipe bonding process.
Because the pipe will be used continuously in the future, And withstand the water pressure, it will inevitably not crack for a long time, causing the phenomenon of running water. In addition, the choice of glue is also very important. You can't choose inferior glue or use glue that has expired. This is a hidden danger in the future. In addition to observing the above principles, the construction unit should also train plumbers to improve their quality, and PE pipes should be used as much as possible on some main pipes and risers. The service life of the Pe tube is long, and its thermal softening can be observed from the outside, and the welding quality is easier to guarantee. Pvc pipes are thermosetting plastics with a short life span and are easy to become brittle after 20-25 years.
