What kind of pipe is UPVC pipe?

UPVC is a plastic pipe used for acid resistance. Such as the desalinated water pipeline for the soft water station.

UPVC, also known as rigid PVC, is an amorphous thermoplastic resin produced by the polymerization of vinyl chloride monomer, along with certain additives such as stabilizers, lubricants, and fillers. 　　In addition to the use of additives, blending and modification with other resins have also been employed to endow it with significant practical value. These resins include CPVC, PE, ABS, EVA, MBS, etc. 　　UPVC has high melt viscosity and poor flowability; even by increasing the injection pressure and melt temperature, there is little change in its flowability. Furthermore, the molding temperature of the resin is very close to its thermal decomposition temperature, resulting in a narrow range of temperatures at which it can be molded; it is therefore a material that is difficult to mold. 　　1. Plastic treatment After being at room temperature for 24 hours, its water absorption is less than 0.02%, so drying is not necessary. If drying is necessary, it can be placed in a hot-air oven at 60-70°C for 3 hours, or in a dryer at 80°C for 1-1.5 hours. 　　Up to 20% recycled material can be mixed with new material, and the amount of recycled material used depends on the final use of the product. The misuse of recycled materials can lead to failure in injection molding; not only is there an excessive amount of recycled content, but another reason is that the material has been reprocessed multiple times. The more times recycled material is reused, the greater the decline in its quality. 　　2. Selection of injection molding machine: Due to the high melt viscosity of UPVC and its tendency to decompose, with the decomposition products being corrosive to iron, specialized plasticizing components and temperature control systems are necessary for its injection molding. 　　For each lock-up force model covered by its products, Marriott has a dedicated UPVC plasticizing injection system, as well as special safety door mechanisms to meet the requirements for core extraction in UPVC pipe fittings. Under normal circumstances, as long as the injection volume meets the weight requirements, using this series of injection molding machines designed for UPVC can produce high-quality products. 　　3. Mold and gate design The mold temperature can be set at 40°C. The length of the flow channel should be short, while the diameter should be large, in order to reduce pressure losses and ensure that pressure can be transmitted to the mold cavity. The gate should be as short as possible; the die-cutting surface must be circular. The diameter of the nozzle opening should be at least 6 mm, and it should have a conical shape with an internal angle of 5°. 　　The die-cut surface of the main flow channel should also be circular; it combines with the cold slug well, and the main flow channel and the gate are connected through the radius of this cut surface, with a diameter that can be 7 mm. 　　The gate should connect the plastic parts using a circular cross-section radius; the shorter this radius, the better. The mold cutting surface must be smooth. 　　The cold slug well prevents semi-solid material from entering the mold cavity, and its importance is often overlooked. 　　The location of the gate must be correct, so that the material can flow smoothly through the flow channels, without getting trapped in sharp corners, debris, or traces of metal; this prevents compression or reduced pressure and ensures that the flow channels remain smooth. 　　Molds are made of stainless steel with a chromium content of at least 13%, and preferably 16%; their Rockwell hardness should be at least 55. Hard steel molds can be chrome-plated to provide protection. 　　After production, the surface of the mold should be carefully cleaned with a mild alkaline solution, followed by the application of an oily spray or a silicone spray. 　　4. Glue melting temperature: It can be measured using the air-jet method, ranging from 185–205°C. The exact melting temperature of UPVC can be determined from the smoothness of the extruded material. If the material is rough and uneven after injection, it indicates that the material is not homogeneous (insufficient plasticization), meaning the set temperature is too low ； If foam forms and a large amount of smoke emerges after shooting, it indicates that the temperature is too high. 　　5. Injection speed: The injection speed should be slow; otherwise, excessive shearing can degrade the quality of the material. When producing extremely smooth thick-walled products from UPVC, multi-stage injection molding molds with controlled filling speeds should be used. 　　6. Screw speed Should be determined in conjunction with the molding cycle. The surface speed of the screw should not exceed 0.15–0.2 m/s. 7. Back pressure: It can reach 150 bar; the lower it is, the better, with 5 bar being a common value. 　　8. Residence time: At a temperature of 200°C, the residence time in the barrel must not exceed 5 minutes. At a temperature of 210°C, the barrel residence time must not exceed 3 minutes. 　　UPVC products: UPVC ball valves, UPVC butterfly valves, UPVC pipes, etc. 　　UPVC pipes: They are essentially plastic pipes, with the joints typically sealed using glue. UPVC pipes lack good resistance to freezing and high temperatures; therefore, they are rarely used for hot and cold water pipelines. PVC pipes are suitable for electrical wiring and sewage drainage systems. In recent years, the scientific community has discovered that certain chemical additives that can make PVC more flexible have a severe impact on the kidneys, liver, and other organs in the human body. These additives can cause cancer, kidney damage, disrupt the body’s functional systems, and affect development.

The pressure rating – 300# refers to 300 pounds; BW stands for butt welding, while SW stands for socket welding. This post was last edited by tuliplt on 2009-4-2 at 13:29.]

UPVC is known as rigid polyvinyl chloride, while PE is known as polyethylene.

BE is the abbreviation for Bevel End, which refers to the welding groove.

Questions 1 and 3 have already been answered; I’ll answer the second question. (2. What do BW and SW mean in \"fitting ends\"?) ) BW butt welding, SW socket welding