(1) In the current construction and installation projects, most of the heating and water supply are PPR pipes (pieces). Its advantages are convenient and quick installation, economical and environmentally friendly, light weight, sanitary and non-toxic, good heat resistance, corrosion resistance, good insulation performance, long life and other advantages. The pipe diameter is one size larger than the nominal diameter. For example, PPR32 is equivalent to DN25, and PPR63 is equivalent to DN50. Pipe diameters are specifically divided into DN20, DN25, DN32, DN40, DN50, DN63, DN75, DN90, DN110. There are many types of pipe fittings, tees, elbows, pipe clamps, and variable diameters. , Pipe plugs, pipe clamps, brackets, hangers. There are cold and hot water pipes, the cold water pipe is a green strip tube, and the hot water pipe is a red strip tube. The valves include PPR ball valves, globe valves, butterfly valves, gate valves, and those with PPR material and copper core inside.
(2) The pipe connection methods include welding, hot melt and threaded connection. PPR pipe uses hot melt connection to be the most reliable, easy to operate, good air tightness, and high interface strength. The pipe connection adopts a handheld fusion splicer for hot-melt connection. Before connecting, remove dust and foreign objects on the pipes and accessories. When the machine’s red light is on and stable, align the pipes (pieces) to be connected. DN<50, the hot melt depth is 1-2MM, and DN<110, the hot melt depth is 2-4MM. When connecting, put the pipe end without rotating Insert into the heating jacket to reach the predetermined depth. At the same time, push the pipe to the heating head without rotation to heat. After the heating time is reached, immediately remove the pipe and the pipe from the heating jacket and the heating head at the same time, and insert it to the required depth quickly and evenly without rotation. A uniform flange is formed at the joint. During the specified heating time, the newly welded joint can be calibrated, but rotation is strictly prohibited. When heating pipes and fittings, prevent excessive heating and make the thickness thinner. The pipe is deformed in the pipe fitting. It is strictly forbidden to rotate during hot melt intubation and calibration. There should be no open flame at the operation site, and it is strictly forbidden to bake the pipe with an open flame. When aligning the heated pipe and fittings vertically, use light force to prevent the elbow from bending. After the connection is completed, the pipe and fittings must be held tightly to maintain sufficient cooling time, and the hand can be released after cooling to a certain degree. When the PP-R pipe is connected with the metal pipe fittings, the PP-R pipe with metal inserts should be used as the transition. The pipe fittings and the PP-R pipe are connected by hot-melt sockets and connected with the metal pipe fittings or the hardware fittings of sanitary ware When using threaded connection, it is advisable to use polypropylene raw material tape as the sealing filler. If the faucet is connected to the mop pool, install a female elbow (threaded inside) on the end of the PPR pipe. During the pipeline installation process, do not use excessive force to avoid damage to the threaded fittings and cause leakage at the connection. Pipe cutting can also be cut by special pipes: the bayonet of the pipe scissors should be adjusted to the diameter of the pipe to be cut, and the force should be evenly applied when rotating and cutting. After cutting, the fracture should be rounded with a matching rounder. When the pipe is broken, the section should be perpendicular to the pipe axis without burrs.
(3) During the pipeline installation, the hydraulic test can be carried out in layers or a single set. The working pressure and test pressure of all pipelines are respectively: the low zone working pressure is 0.4Mpa, the test pressure is 0.6Mpa, the high zone and the middle zone are calculated with 0.6Mpa, and the test pressure is 0.9Mpa. After the pipeline system is installed, Comprehensive inspection, check the installed pipes, valves, gaskets, fasteners, etc., after all meet the design and technical specifications, remove the fittings that are not suitable for pressure test with the pipeline, replace with temporary short pipes, and close all openings , And pour water from the lowest point, and vent the air from a high point. Purge the pipes that have passed the pressure test until the dirt is washed away, and complete various purge and cleaning records and pressure test records. The test pressure is 1.5 times the working pressure of the system, but shall not be greater than the allowable pressure of the pipe. Water should be filled slowly during the test, and the seal should be checked after filling. The pressure should be increased slowly to the test pressure with a hand pump, and the pressure should be stabilized for 1 hour, the pressure drop is less than 0.05Mpa, and then reduced to 1.15 times the working pressure, the pressure should be stabilized for 2 hours, and the visual inspection should be performed. 0.03Mpa is qualified.
(4) During installation, pay attention to avoiding sharp objects when handling and installing pipelines to prevent pipeline damage. During pipeline installation, prevent organic pollutants such as paint from contacting pipes and fittings. The openings where installation is interrupted or completed must be temporarily closed to prevent debris from entering. The water supply piping system should be flushed with water before acceptance. The flushing water flow rate should be greater than 2m/s. When flushing, no dead corners should be left. The faucet of each water distribution point should be turned on. The lowest point of the system should be set up with a drain. The cleaning time should be controlled until the water quality of the flushing outlet is equal to the inlet water. After the drinking water system is flushed, the pipes should be filled with 20-30mg/l free chlorine water for disinfection. Chlorine-containing water should stay in the pipe for more than 24h. After the pipeline is disinfected, it is rinsed with drinking water, and the water quality meets the current national standard “Sanitary Standard for Drinking Water” after sampling and inspection by the health management department before it can be delivered to use. Within 30 minutes, allow two pressure increases to reach the specified test pressure. Pay attention to the conversion of pipe diameter when budgeting and lifting materials. The section of the chart is DN20 and PPR25 pipes (pieces) should be mentioned. The products of the same manufacturer must be used, because the products of different manufacturers contain different proportions of ingredients. It will cause weak bonding or failure to bond.