Construction and maintenance of pvc pipe
The key methods of connecting PVC pipes are sealing rubber rings, bonding and flange butt joints. Pipes with a diameter greater than or equal to 100 mm generally use rubber ring interfaces. The diameter of the pipe is less than 100 mm The pipes generally use adhesive joints, and some use union joints. When the pipes pass over the sewers or other pipes, metal pipes are generally used. At this time, the plastic pipes and metal pipes are connected by flanges. All are flanged.
1 When the small-diameter pipe is glued by solvent, the socket must be rounded to form a groove, and the fracture surface should be flat and the axis should be straight, so as to be firmly bonded and avoid water seepage.
2 Generally, PVC pipes with a pipe diameter greater than or equal to 100 mm use rubber ring interfaces. Before installation, personnel must be organized to chamfer the position of the pipe jack, and it is also necessary to check whether the quality of the rubber ring can meet the standard. Wipe the circle clean.
3 The ditch excavation of the traditional pipeline installation only requires that the pipeline can be put into the ditch and can be sealed. When the original soil layer is not loosened, it is not necessary to compress the cushion.
4. Generally, the branch pipe of pvc pipe can be split with a tee or a vertical water stop. In the construction of the project, a saddle-shaped fitting can be added and half a two-in-one three-way, and clamped with U-shaped bolts, it will be thickened. The pipe wall is then drilled directly on it to open the teeth, and then the external thread plastic parts are used to connect it out. The experiment marks that the pressure test after the construction of the project can fully meet the requirements of the specification. In addition, the direction of the torque generated by the flowing water in the pipe, such as Thrust piers should be set at elbows, tees and pipe end sealing plates to accommodate the torsion of flowing water.
As a new type of non-metallic pipe, 5pvc pipe cannot be surveyed to its actual direction with the current metal pipe survey equipment, but if a wire is laid on the pipe during the construction of the pipe laying project, this problem can be easily solved.
The essence of PVC pipe is a type of vacuum plastic film, which is used for surface packaging of various panels, so it is also called embellishment film, adhesive film, and is used in many industries such as building materials, packaging, and medicine. The proportion of building materials industry Larger, 60%. On the other hand, it is the packaging industry, and there are other industries that are used in small areas. PVC pipes are divided into PVC water supply pipes and drainage pipes, which are used for municipal water supply and drainage, industrial water supply and drainage, and civil water supply and drainage. Irrigation, vegetation sprinkling, etc.
Five common problems in the production of PVC pipes
In the process of processing, because PVC is a heat-sensitive material, even adding a heat stabilizer can only increase the dissolution temperature and increase the stable time of insolubility, which requires strict control of the molding processing temperature of PVC. RPVC in particular, because its processing temperature is very close to the dissolution temperature, often dissolves due to poor temperature control. Therefore, the extrusion temperature should be determined according to the formula, the characteristics of the extruder, the structure of the die, the speed of the screw, the position of the temperature measurement point, the deviation of the thermometer, and the depth of the temperature measurement point.
1. Temperature control Temperature control is a key factor in the actual operation of extrusion. The controlling factors for extrusion are barrel temperature, diameter temperature and die temperature. Ultra-low temperature, poor plasticization, dull appearance of the pipe, poor mechanical properties, and product quality not up to the requirements: if the temperature is too high, the material will dissolve, and the product will appear discolored.
2. The screw speed is increased, the extrusion volume is increased, and the production volume is increased, but it is very easy to cause potential safety hazards in plasticization, resulting in unevenness in the inner cavity of the tube, and the strength is reduced. achieve the best. The temperature control of the screw interferes with the transport speed, plasticizing and melting quality of the material. The extrusion pipe must pass cooling water, and reducing the screw temperature is beneficial to improve the plasticization quality. The screw is about 50~70℃ according to the temperature of the cooling water.
3. Traction speed In the actual operation of re-extrusion, it is very important to adjust the traction speed. After the material is extruded, melted and plasticized, it is continuously pulled from the die head and into the setting equipment, cooling equipment and pulling equipment. The pulling speed should match the squeezing speed. Usually in production under normal circumstances, the pulling speed should be about 1%~10% faster than the extrusion speed of the pipe.
4. Compressed air and working pressure compressed air can blow the tube to maintain the necessary roundness. Work pressure should be sufficient. The working pressure is very small, the pipe is not round, the pressure is large, the mandrel is cooled, the inner cavity of the pipe is cracked, uneven, and the quality of the pipe is reduced. In addition, the working pressure must be stable. If the working pressure fluctuates, it is very easy to cause damage in the pipe.
5. The temperature of sizing equipment and cooling equipment is used to extrude different plastic products. Different sizing and cooling methods are used. The cooling material can be air, water or other liquids. The temperature must be controlled. The temperature is mainly related to productivity, product internal stress.
What are the advantages of PVC pipes
PVC pipe fittings have the following advantages:
1) Light weight: Because of the light weight, it can greatly reduce the transportation cost and the construction strength of the installation.
2) No harm to water quality (environmental hygiene and non-toxicity): The raw materials are completely composed of carbon and hydrogen without any toxic heavy metal salt stabilizers. The best pipe material for tap water piping.
3) Good aging resistance: when the working water temperature is 70 degrees, the softening temperature is 140 degrees.
4) High transverse mechanical strength (high impact resistance): excellent water pressure resistance, external pressure resistance, impact resistance, etc., suitable for various standards.
5) Long service life: Under the application temperature and pressure of the rated value, the service life of the pipe is more than 50 years, and it has the ability to block ultraviolet rays and radiation, so that the product will never fade.
6) Good corrosion resistance: Except for a few hydrogenating agents, it can resist the corrosion of various chemical media, has excellent acid resistance, alkali resistance, corrosion resistance, not easy to rust, not easy to corrode, not easy to grow bacteria, no electricity Chemical corrosion, suitable for main use in the chemical industry