Currently, a wide range of new types of plastic pipe market, are commonly used: PP-R pipe, PB pipe, PE-X pipe, aluminum-plastic composite pipe, ABS plastic pipe, PP-R pipe because of its reliability much pet owners stare and engineering application is also more. Following a brief PP-R pipe application in heating engineering construction on the ground.
1, PP-R pipe material selection
The hot water pipe and pipe fittings with corresponding nominal pressure should be selected according to the working pressure of the project, the working pressure of the system, the investment cost of construction unit, the durable service life and so on.
2, PP-R pipe fitting material approach test
Sampling inspection of the material should be carried out, the pipe and pipe fittings inside and outside the wall should be smooth, no bubbles, cracks, cracks, peeling and obvious marks, depression, and the color is basically the same.
Corresponding lines, specifications, models, batches, nominal pressure, etc. should be clearly marked on the surface of the pipe. The end face of the pipe shall be perpendicular to the axis of the tube.
Fittings should be complete, no defect, no deformation, no cracking, mold closing, gate should be smooth. The thickness of the pipe fittings should be not less than the wall thickness of the corresponding pipe.
Material inspection report, certificate, approval certificate is complete and effective, batch and pipe on the marked consistency.
3, material storage
Pipes and fittings should not be exposed to prolonged sun exposure, should be stored in a well ventilated, temperature not exceeding 45 DEG C warehouse and a simple shed, away from the heat not less than 1m, storage of the pipe pile set height should not exceed 1.5 m, in order to avoid the bending of the tube during storage, stacking frame should be flat.
4, PP-R pipeline construction process
PP-R pipe construction technology is as follows:
Ready to install, vertical stem pipe installation, vertical stem tube pressure test, buried PP-R pipe installation, household pressure test, pressure maintaining, household riser and branch pipelines installation, the installation of the radiator system, pressure testing and flushing, instrument installation, insulation
The following introduces the installation technology of PP-R pipe:
PP-R pipes arranged along the ground around in the center of the pipe wall and the distance between the two tubes of center distance distance should comply with the design requirements, laying on the ground after pouring layer, pipe spacing of not greater than 60mm and steel nail is fixed on the floor. Hot melt connection. When installed, the floor is clean, the ground is high to chisel, keep the ground flat, elevation line. The position of the water supply pipe and the outlet position of the ground are clearly marked, so as to avoid the phenomenon that the water supply pipe is connected with the reverse of the water supply pipe and is not accurate.
After the pipeline installation is completed, the water pressure test is carried out. The test pressure shall be carried out according to the design requirements. Under the test pressure, pressure 1H, pressure drop should not be greater than 0.05Mpa, and then down to 1.15 times the working pressure, the pressure regulator 2h, pressure drop should not be greater than 0.03MPa, at the same time, the connection of no leakage phenomenon.
After pouring layer construction, pressure maintained in the tube 0.5MPa, once the gauge pressure drops, found the leak, take emergency measures to deal with.
After the construction of the surface layer is completed, the position and direction of the pipeline should be indicated in the obvious position, and no sharp objects such as the impact of the pipeline or the nail metal nail are strictly prohibited.
Pipe hot melt connection of the operation process according to the technical requirements of the manufacturer, hot melt connection time, temperature, depth of insertion should be strictly controlled.
5, PP-R pipeline construction should pay attention to the problem
(1) personnel training hot melt connection requires high technology, the operator must go through professional training, strictly according to the requirements of the operation.
(2) welding interface to check if the nozzle of the oil or sediment, can cause false fusion phenomenon, directly affect the quality of the construction, in the installation of pipes and fittings must pay attention to the process of storage and cleaning. Interface quality bad reason mainly has: Bearing skew the fusion interface, socket heating is not uniform, and the bell mouth temperature is too high, the surface of the socket is not melting. PP-R pipe connecting mouth shall comply with the following requirements: pipeline joint surface should have a uniform hot melt ring, not local melt tumor or molten connecting ring concave and convex inequality.
(3) pressure test household buried heating pipe in front of the cast-in-place layer construction pressure test, pressure test according to the design and specification requirements, after pouring layer construction keep 0.5MPa pressure, once leakage phenomenon immediately re install; after the completion of the construction on the ground to make a mark, to facilitate maintenance and search, to prevent the fitting failure.
(4) the interface position of a pipe size lock valves, heat table is in pressure, wash after installation of. So it is necessary to the connection pipe segment replacement. Due to locking valve and heat meter are arranged on both ends of the metal parts, need to use with a metal block hot-melt pipe fitting for connecting piece, the pipe must be according to the actual length measurement accurate, otherwise, would be wasteful.
(5) with a metal insert of PP-R pipe with a metal connecting piece, pay attention to moderate force, in order to avoid the metal embedded pieces from the PP-R pipe extrusion. When necessary, torque wrench test can be used.
(6) PP-R pipe installation should pay attention to the practice of waterproof layer.