Compared with traditional pipelines, PVC-U pipelines have the advantages of light weight, corrosion resistance, low water flow resistance, energy saving, quick installation, and low cost. They are widely promoted and applied and have significant benefits. Since the 1980s, my country has piloted the application of PVC-U pipelines in municipal engineering and construction projects. After more than 10 years of promotion, PVC-U pipelines have developed rapidly, but the per capita consumption is still less than developed in the United States, Japan, and Western Europe. 1/15 of countries and regions. As the Ministry of Construction and other five departments jointly issued the notice of "vigorously develop chemical building materials", the promotion and application of PVC-U plastic pipes have been increased. Sanitary and environmentally friendly PVC-U water supply pipes have continuously replaced high energy consumption and high pollution. , Traditional pipelines with high cost and low sanitary indicators. Widely used in: urban tap water delivery and water supply engineering, building internal and external water supply engineering, industrial and mining enterprise water supply engineering, buried fire water supply engineering, farmland water conservancy water delivery and irrigation engineering, gardening and greening water supply engineering, aquaculture water supply and drainage engineering, etc. Good economic and social benefits.
The production standards of PVC-U water supply pipes include British standard, American standard, Japanese standard, IS0 international standard, national standard (GB), etc. Domestic manufacturers basically adopt the national standard organization to produce, that is, the pipe standard number: GB/T10002.1 -1996, pipe fitting standard number: GB10002.2-1998. We recommend that users adopt national standard products, which conform to national conditions, have a more guaranteed quality, and are easy to use with other pipes (traditional pipes and other grades of PVC-U pipes).
1. Pressure regulation of pipeline. (1) The pressure shown in the PVC-U water supply pipeline is expressed as the nominal pressure, expressed in Mpa, 1Mpa≈10kgf/cm2 is the working pressure of the pipe under the condition of 20℃ and the conveying medium. However, as the temperature of the medium increases (mediums above 50°C must not be transported), the working pressure decreases, which objectively requires consideration of a sufficient pressure safety factor in the selection of water supply pipelines. (2) The nominal pressure of water supply pipes is specified as: 0.6Mpa, 0.8Mpa, 1.0Mpa, 1.25Mpa, 1.6Mpa, etc. 5 kinds. (3) The nominal pressure of pipes of the same specification is generally divided by the wall thickness of the pipes. (4) The minimum diameter of the pipe for each pressure zone is specified as: the minimum diameter of 0.6Mpa pipe is 63mm, the minimum diameter of 0.8Mpa pipe is 50mm, the minimum diameter of 1.0Mpa pipe is 40mm, and the minimum diameter of 1.25Mpa pipe is 32mm. , The minimum diameter of 1.6Mpa pipe is 20mm and 25mm. (5) The nominal pressure of water supply pipes is generally 1.6Mpa, and it is matched with pipes of various pressures.
2. The specifications of the pipeline. (1) The specifications and dimensions of PVC-U water supply pipes stipulated by national standards are the nominal outer diameter, and the pipe fittings are the nominal inner diameter, which is indicated by "φ". (2) The specifications and dimensions of PVC-U water supply pipelines are: φ20, φ25, φ32, φ40, φ50, φ63, φ75, φ90, φl10, φ125, φ140, φ160, φ180, φ200, φ225, etc. Domestic companies basically do not produce φ125, φ140, φ180, φ225 and other specifications of pipelines, so try to avoid choosing these types of pipelines in engineering design and use. (2) The largest domestic pipe specification is φ800 pipe produced by Hebei Baoshuo Pipe Branch. Ronglin Plastics Company can produce φ710 pipe. It is recommended to avoid designing φ800 or more pipes in the design of PVC-U pipes, and use φ630 or less as the pipe should. (3) National standard PVC-U pipes and traditional national standard pipes can generally be matched. The corresponding relationship between the nominal diameters of national standard PVC-U pipes and traditional national standard pipes: φ20-DNl5, φ25-DN20, φ32-DN25, φ40 -32, φ50-DN40, φ63-DN50, φ75-DN65, φ90-DN80, φ11O-DNl00, φ160-DNl50, etc.
3. Regulations on the interface method of the pipeline. (1) There are generally three ways to connect water supply pipes: rubber ring interface, glue interface, and flange connection. A. The connection method of the rubber ring is to expand one end of the pipe into a socket with a groove by an automatic flaring machine, and put a flexible rubber sealing ring, and the unflared end of the pipe is inserted into the socket with the sealed enclosure. To complete the connection. B. The glue connection method is to expand one end of the pipe into a smooth socket, and apply special glue to the outer surface of the other end of the unflared pipe and the inner surface of the expanded socket, and then insert the socket to complete the connection. c. Flange connection method is when the pipe is connected with traditional pipes, butterfly valves, gate valves, flow meters, etc., the connected end of the pipe is connected with the PVC-U flange and then fastened with screws. (2) There are generally two ways to connect water supply pipes: glue interface and flexible interface. A. Glue sticking interface means that the socket of the pipe fitting is injection molded into a smooth socket, and special glue is applied together with the pipe to complete the connection through the socket. B. The flexible connection method is the pipe fitting method to mold a socket with a groove, and an additional compression screw cap is equipped with a compression rubber sealing ring. When the corresponding pipe is inserted, the compression screw cap is tightened to complete the connection.
1. Lightweight, convenient for handling and unloading ── Less density, convenient for handling, handling and construction.
2. Excellent corrosion resistance ──── It has excellent acid resistance, alkali resistance and corrosion resistance, which is very suitable for the chemical industry.
3. Small fluid resistance ───── The inner wall of the pipe is smooth, its roughness coefficient is only 0.009, and the fluid resistance is small, which effectively improves the hydraulic conditions of the pipe network and reduces the operating cost of the system.
4. High mechanical strength ───── The pipe has good pressure resistance, impact resistance and tensile strength.
5. Simple construction ────── The pipeline connection is quick and easy, and the construction engineering cost is low.
6. Low cost ────── Low price, convenient transportation and construction, and long service life, so the overall cost is low.
7. Does not affect water quality ───── It is confirmed by dissolution test that it does not affect water quality and is suitable for large-scale application.
Product application range:
1. Indoor water supply and reclaimed water system for civil and industrial buildings.
2. Buried water supply system for residential quarters and factories.
3. Urban water supply pipeline system.
4. Water treatment pipeline system of water treatment plant. 5. Marine aquaculture.
6. Garden irrigation, well sinking and other industrial pipes.
In order to ensure that the PVC-U pipeline has a better use environment, can avoid external loads, and achieve the expected service life, the pipeline should be reasonably arranged and laid.
⑴ Generally, the pipeline should be set up explicitly, and in places where the pipeline may be impacted, it should be set up in secret or take protective measures.
⑵The water supply pipes for the open application should be arranged near the wall, corner or column near the sanitary appliances or equipment with large water supply.
⑶ Water supply pipes must not pass through bedrooms, storage rooms, flues and air ducts.
⑷ Lightweight materials should be used for heat insulation when laying water supply pipes outdoors exposed to sunlight.
⑸ It is strictly forbidden to touch organic chemicals such as waterproof paint when the pipeline is darkly applied, so as not to affect the water quality and damage the pipeline.
⑹When the pipeline passes through the roof and basement, metal waterproof flexible casing and effective waterproof measures should be installed.
⑺ When the water supply pipeline and other pipelines are laid in parallel in the same ditch (rack), they should be arranged along the side of the ditch (rack). When laid up and down in parallel, they should not be laid on the hot water pipe or steam pipe, and the plane position should be staggered; When cross laying, protective measures should be taken or metal casing should be used for protection.
⑻The water supply pipeline should be far away from the heat source, the standpipe should not be less than 400mm away from the edge of the stove, and the heating pipeline should not be less than 200mm, and the temperature of the outer wall of the pipe should not be higher than 40℃ due to the radiation of the heat source.
⑼ When the straight line length of pipelines in industrial buildings and public buildings is greater than 20m, measures should be taken to compensate for pipeline expansion and contraction.
⑽The connection between branch pipes and main pipes, and equipment containers should make use of pipe angles to naturally compensate for the expansion and contraction of pipes.
⑾The telescopic length of the pipeline can be determined as follows:
In the formula: △L—pipe extension length (㎜)
△T—Calculated temperature difference of pipeline (℃)
L—pipe length (m)
a—Linear expansion coefficient: (mm/m·℃) 7×10ˉ7=0.07
The calculated temperature difference of the pipeline is determined as follows:
In the formula: △ts—the maximum temperature difference of the water in the pipeline (℃)
△tg—Maximum temperature difference of air outside the pipe (℃)
⑿ The temperature difference of the pipeline affects the parallelism of the pipeline layout, causing the pipeline to bend or even pull off the connection and damage the pipeline system. In order to solve the problem of thermal expansion and contraction, in addition to the medium and large diameter pipes can be compensated by flexible loop connectors, small pipes Free arm setup can be used to compensate. The length of the free arm can be determined as follows:
Where: Lz—minimum length of free arm (MM)
△L—The telescopic length of the pipeline (mm)
K—material scale factor, which is 33
d—Outer diameter of pipe (㎜)
⒀Fixed fulcrums should be set at the position where the riser passes through the floor and the level in the building.