Introduction of the application principle of PE pipe in water supply and drainage system
With the acceleration of China's urbanization process and the enormous pressure of population, resources and environment, in order to ensure the sustainable development of the national economy, the Chinese government has increased investment in urban infrastructure year by year, and the construction of municipal public pipelines has been accelerating. The specifications are constantly enriched, the output is increasing, the quality is constantly improving, especially the plastic tube development is faster, and it has become a hot spot of investment today.
In 1933, the British ICI company first discovered PE. It has been developed that PE is produced by a variety of processes, and a wide range of resins with a variety of structures and characteristics and a variety of uses, has accounted for one-third of the world's synthetic resin production, ranking first. One of the best uses of PE is that it can be used to produce pipes for transporting any medium other than strong acid and alkali. According to foreign data spinning, the annual consumption of PE pipes in the world's water supply pipelines is about 1 million tons. Widely used in water supply, gas transportation, sewage, agricultural irrigation, fine particle solids transportation, and oil, chemical and postal communications.
The "National Chemical Building Materials Industry "10th Five-Year Plan" and the 2010 Development Plan Outline pointed out that the promotion and application of plastic pipes mainly consists of UPV-C and PE pipes. By 2005, in the process of new construction, reconstruction and expansion in the country, 70% of the building drainage pipelines use plastic pipes 50% plastic pipes, 60% of the building water supply, hot water supply and heating pipes use plastic pipes, and 50% of urban water supply pipes use plastic pipes. Pipes, 70% of the water supply pipes in villages and towns use plastic pipes, 20% of urban gas pipes use plastic pipes, and 80% of wire sheathed pipes use plastic pipes.
First, the water supply and drainage system engineering pipe types and technical, economic and other aspects of comparison:
(1) Type of pipeline
Water supply and drainage system engineering mainly includes: polyethylene pipe (PE), steel pipe, spheroidal pipe, gray cast iron pipe, cement pipe, glass fiber reinforced plastic sand pipe, UPV-C pipe and so on.
(1) Polyethylene pipe (PE)
Polyethylene is classified into high density polyethylene (HDPE), medium density polyethylene pipe (MDPE) and low density polyethylene pipe (LDPE) according to its density. Polyethylene pipes can be divided into single-layer solid wall pipes, double-wall corrugated pipes and spiral wound pipes according to different structural forms. Double-wall corrugated pipe and spiral wound pipe are mainly processed by HDPE raw materials, mainly used in urban drainage, single-layer solid wall HDPE is mainly used in urban water supply and urban gas transportation. Single-layer solid-wall MDPE pipe is mainly used in urban gas transportation. Single-layer solid wall LDPE tubes are widely used as agricultural irrigation pipes and industrial ordinary pipes.
(2) FRP sand pipe
The glass fiber reinforced plastic sand pipe is made of short glass fiber centrifugal or long glass fiber winding, and is made by the middle sand sanding process. The pipe wall is slightly thick and the hoop stiffness is large. It can be used as a buried pipe to withstand internal and external pressure. The pipe diameter can be from 500 diameter. ~ 2600 mm in diameter, the glass fiber reinforced plastic sand tube is brittle, only suitable for large diameter, and during the construction process, mechanical collision is prone to dark injury, and the dark injury is not easy to find, affecting the service life.
(3) Rigid polyethylene pipe UPV-C pipe
The UPV-C tube has high impact resistance and chemical resistance. It can be added according to the use requirements, different additives can be added in the process, so that it has the physical and chemical properties to meet different requirements, UPV-C tube has long life, good sealing, etc., but the UPV-C tube in the process There are heavy metal stabilizers, which will gradually ooze out during use and affect the water source.
(4) Steel pipe
The biggest defects of steel pipe are short service life, strong corrosiveness, poor sealing performance, easy leakage, high price, and poor adaptability to uneven surface settlement.
(5) Spherical tube
The cost of the spheroidal tube is high, the average price is 10% to 15% higher than that of the PE tube, and the corner of the connection interface is too large to cause leakage.
(6) Gray cast iron pipe
The gray cast iron pipe has a short service life, a large friction coefficient, a poor sealing property, and is easy to leak.
[Plastic pipe and pipe fitting method]
1. Before the pipe and pipe fittings are bonded, apply a dry cloth to wipe the socket side and the outside of the socket. When the surface is sticky with oil, wipe it with acetone.
2. The pipe section should be flat and vertical pipe axis and chamfered; before the bonding, the inserted marking line should be drawn and the test insertion should be carried out. The test insertion depth can only be inserted into the original depth of 1/3~1/2. When the gap is too large, the bonding method is strictly prohibited.
3. When applying adhesive, apply the inner side of the socket first, then apply the outside of the socket. When applying the socket, apply a proper amount from the inside to the outside in a uniform direction. Do not leak or apply excessive amount (200g/m2).
4. After the adhesive is applied, it is advisable to keep the applied external force unchanged within 1 minute, and keep the straightness and position of the interface correct.
5. After the bonding is completed, wipe out the excess adhesive that is squeezed out in time, and do not force or forcibly load during the curing time.
6. Bonded joints shall not be constructed in rain or water, and shall not be operated below 5 °C.
7. Connection procedure: preparation → cleaning work surface → trial insertion → brush adhesive → bonding → curing.
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Battery spring, divided into positive battery spring, negative battery spring, positive and negative battery spring
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