How to weld PP pipes, what is the difference from PPR welding?

PP pipe welding depends on the pipe fittings. If the PP pipe fittings are hot-melt sockets, they should be welded with a hot melter. If they are hot-melt butt-welded, they should be welded with a hot-melt butt welder. If the PP pipe fittings are socket-type, they can be welded with a plastic welding gun.

Different welding methods:

1. PPR welding: During welding, heating or pressure or both are used together, with or without filler materials, so that the workpiece passes between atoms or molecules. The process of bonding to form a permanent connection.

2. PP welding: It uses the chemical reaction of exothermic flux as the heat source to fix the ends of the two workpieces to be welded in the mold in advance to generate high temperature to connect the workpieces.

Welding items are different:

3. It can be seen that welding and hot melting are both welding, and welding generally requires filler materials, while hot melting does not require filler materials. PP pipes mainly use hot melt, and metal pipes mainly use welding.

PP pipe and ppr pipe welding method:

4. Use a special hot melter for PPR and pp pipes, use corresponding heat parts according to the pipe diameter, and the two ends to be bonded must be Heating at the same time, while heating, lean toward the middle of the heater. When it reaches the root, stop for 2 seconds and pull out the docking. If the time is short or long, the bonding may be loose and water leakage may occur.

5. Special pipe shears should be used to cut the pipe. After cutting the pipe, the burrs must be removed, and the connecting surfaces of the pipe and fittings must be clean, dry, and oil-free.

6. When making a hot-melt connection with the hot-melt machine, you should first turn on the power and heat it to reach the working temperature. Only after the indicator light turns on can you start the hot-melt operation.

7. When welding pipe fittings with installation directions such as elbows or tees, attention should be paid to their direction according to the drawing requirements, and markings should be made on the pipe fittings in advance to ensure that the installation angle is correct. After heating, the pipe section should be When inserting to the marked depth, adjusting and straightening, the pipe and fittings should not be rotated, and the pipe should be kept perpendicular to the axis so that it is on the same axis.

Extended information:

Type III polypropylene (PP-R)

1. Properties and production process: PP-R is non-toxic, hygienic and recyclable use. The Vicat softening temperature of PP-R is 131°C, the maximum use temperature is 95°C, and the long-term use temperature is 70°C. It is a heat-resistant, thermal insulation and energy-saving product. Its density is 900 kg/cubic meter. PP-R pipes are produced using the extrusion molding process, and PP-R pipe fittings are produced using the injection molding process.

2. Production standards: At present, there is no unified national pipe standard in China. PP-R production lines are mostly imported from Germany, and PP-C production lines are mostly imported from South Korea. Most manufacturers formulate their own corporate standards with reference to German standards.

3. Connection methods and accessories: PP-R pipes and accessories are connected by hot melt connection. When PP-R is connected to metal pipe fittings, polypropylene pipe fittings with metal inserts are used as a transition. The pipe fittings are hot-melt connected to PP-R and threaded to the metal pipe.

PP pipe connection method:

4. Use sandpaper to remove the surface layer of the joint end of the pipe or piping parts. If there is still grease on the surface, wipe it with vinyl chloride or acetone. Clean; put the two ends into the welding sleeve, and the two ends must be inserted into the middle point of the welding sleeve. There should be no water at the two ends when inserting.

5. Then insert the secondary wire of the welding controller and start welding. During the process, it is not allowed to move or touch, cut off the power supply midway or loosen the joint point of the secondary wire. Wait for the joint point to wait one hour after the welding is completed. Only after complete cooling can pressure be applied to the inside of the tube and the tube can be pulled from the outside to ensure that the joints are not deformed.

6. The straight pipe must be cut with a pipe cutter first, and the socket must be very flat. The part where the socket end is inserted into the welding sleeve must not be scratched or deformed more than 1 mm. The used welding sleeve must not be used again. , if the welding sleeve is damaged or deformed, it should be discarded and not used. If the connection fails, a new welding sleeve should be replaced and re-welded.

7. If the welding sleeve fails due to the power cut off during the process, wait until it is completely cooled before plugging in the secondary wire and re-welding. If stress needs to be added to the pipe immediately after the welding is completed, you can pour cold water on it. It cools.

8. End edge welding method. In special cases where electric welding sleeves cannot be used for joining, the end edge welding method can be used. Before welding, a pipe cutter must be used to cut the socket very flat. Then use For edge welding, the welding method and heating time must be completely in accordance with the instructions and heating schedule of each type of welder.

Note: After welding is completed, once the joint part has cooled, the inside of the pipe at the joint must be flattened, otherwise debris will accumulate at the joint and cause blockage in the future.

Reference: Baidu Encyclopedia-PP Pipe