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Depth analysis ppr tube

- Dec 21, 2017 -

Introduction

PPR pipe interface using hot melt technology, fully integrated between the pipe together, so once the installation of pressure test passed, never again leakage, high reliability. However, this does not mean that the PPR pipe is a water pipe without any defects. The high temperature resistance and the pressure resistance are slightly worse. The long-term working temperature can not exceed 70 ° C. Each length is limited and can not be bent. If the pipe is long or at a corner More, in the construction will use a large number of joints; cheap pipe fittings prices are relatively high. From a comprehensive performance point of view, PPR pipe is the current cost-effective pipe, it becomes the first choice for home improvement water pipe material.


There are two main colors of PPR tubes available in the market, white and gray, and why there is such a difference. The dealer's answer is due to the different PPR particles used.


In the general transformation of hydropower, the original pipes will be replaced, home improvement companies and businesses in the decoration decoration PPR pipe installed when all the selection of hot water pipe, even through the cold water is also used hot water pipe. Their argument is due to the technical parameters of the hot water pipe is higher than the cold water pipe, and the price is not much difference, so the waterway transformation are used hot water pipe. Another fact is that even if you want to buy cold water pipe on the market is also very difficult to buy, because the cold water pipe only supply tooling market, not for the home improvement market.


Pipe diameter PPR pipe diameter can be from 16mm to 160mm, home improvement is mainly used 20mm, 25mm two (commonly known as 4 points, 6 points), of which 4 points used more.


First, what is PP-R tube?

PP-R pipe, also known as three polypropylene pipe, random copolymer polypropylene by extrusion into a pipe, injection molding into the pipe. It is a new type of plastic pipe product developed and applied in Europe in early 90s. In the late 1980's, PP-R was used as a new generation of pipe material by vapor phase copolymerization process to make about 5% PE randomly and uniformly polymerize (random copolymerization) in the molecular chain of PP. It has good impact resistance and long-term creep properties.


Second, what is the relationship between PP-R and PP-C?

In the previous period, PP-C pipes and fittings appeared on the domestic market, and the installation method was consistent with PP-R. Many people do not know what is the difference between PP-R and PP-C, causing a lot of misunderstanding and confusion. International standards, PP hot and cold water pipes PP-H, PP-B, PP-R three, no PP-C. PP-C tube on the market is actually PP-B tube, the raw material is the block copolymer polypropylene pipe special material. PP-B pipe is a kind of hot and cold water pipes, the price is cheaper, the heat, pressure resistance and PP-R gap is very big. For example: the use of conditions grading 2, design pressure 0.6MPadn25mm pipe, PP-R pipe wall thickness 3.5mm, PP-B (PP-C) pipe wall thickness to 5.1mm; design pressure 0.8MPadn25mm, PP-R pipe wall thickness 4.2mm , PP-B (PP-C) can not be used. Because the wall thickness is too thick. PP-R pipe structure of the same size and structure of the PP-C pipe, the use of much lower conditions, can not be mixed with the PP-R pipe use, but can not determine the conditions of use, PP-C pipe instead of PP-R pipe. Conditions of use 2 that the design temperature of 70 ℃, for hot water.

Third, what are the characteristics of PP-R tube?

PP-R pipe in addition to the general plastic pipe light weight, corrosion resistance, non-scaling, long life and other characteristics, but also has the following main features:

1, non-toxic, health. PP-R's raw material molecules only carbon, hydrogen elements, there is no harmful toxic elements exist, hygienic *, not only for hot and cold water pipes, but also for pure drinking water system.

2, energy-saving insulation. PP-R pipe thermal conductivity of 0.21w / mk, only the steel pipe 1/200.

3, better heat resistance. PP-R pipe Vicat softening point of 131.5 ℃. The maximum working temperature up to 95 ℃, to meet the building water supply and drainage specifications in the use of hot water system requirements.

4, long service life. PP-R pipe at the working temperature of 70 ℃, working pressure (P.N) 1.OMPa conditions, the service life of up to 50 years; room temperature (20 ℃) life of up to 100 years.

5, easy installation, reliable connection. PP-R has good welding performance, pipe, pipe fittings can be hot melt and fused connection, easy installation, fittings *, the strength of the connection part is greater than the strength of the pipe itself.

6, the material can be recycled. PP-R scrap was cleaned, crushed and recycled for pipe, pipe production. The amount of recycled materials does not exceed 10% of the total, does not affect product quality.


Fourth, PP-R tube main purpose what?

1, building hot and cold water systems, including central heating system;

2, building heating system, including floor, siding and radiant heating system;

3, can be directly drinking pure water supply system;

4, the central (centralized) air-conditioning system;

5, transport or discharge of chemical media and other industrial piping systems.


Fifth, how safe and economical selection of PP-R tube?

1, pay attention to the overall pipeline use coefficient C (ie, safety factor) to determine:

In general, long-term continuous temperature <70 ℃, optional C = 1.25; in important occasions, and long-term continuous use temperature ≥ 70 ℃, and may be a long time at a higher temperature operation, optional C = 1.5;

2, for cold water (≤40 ℃) system, use P.N1.0 ~ 1.6MPa pipe, fittings;

For hot water system selection ≥ PN2.0MPa pipe, pipe fittings.

3, after considering the above three principles, the SDR of the pipe should not be greater than the SDR of the pipe, that is, the wall thickness of the pipe should not be less than the wall thickness of the pipe of the same specification.


Six, PP-R pipe installation and construction should pay attention to what issues?

1, Compared with metal pipe, PP-R pipe has low hardness and poor rigidity. It should be protected during handling and construction to avoid mechanical damage caused by improper external force. Under concealment to mark the location of the pipe, so as not to damage the second renovation pipeline.

2, PP-R pipe below 5 ℃ there is a certain low temperature brittleness, winter construction should be careful, when cutting with a sharp knife to slow cutting. Can not be installed on the pipeline pressure, percussion, if necessary, vulnerable to external parts covered with protective objects.

3, PP-R tube long-term degradation by ultraviolet light degradation, installation outdoors or in direct sunlight must be bandaged dark protective layer.

4, PP-R pipe in addition to the metal pipe or water connection using threaded inserts or flanges and other mechanical connections, the rest should be used hot melt connection, the pipeline integration, no leakage point.

5, PP-R pipe larger linear expansion coefficient (0.15mm / m ℃), installed or unburied buried pvc pipe must be taken to prevent the pipe expansion and deformation of the technical measures.

6, after the installation of the pipe in the sealing tube (Buried) and cover the decorative layer (non-buried Buried secret) must be pressure test. Cold water pressure test pressure of 1.5 times the system working pressure, but not less than 1MPa; hot water pipe test pressure of 2 times the working pressure, but not less than 1.5MPa. Test pressure time and method of technical regulations.

7, PP-R pipe or non-buried Buried buried pvc pipe, it must be installed in accordance with the provisions of hangers.


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