1. PE/AL/PE (Polyethylene/Aluminum/Polyethylene);
2. PE/AL/PEX (Polyethylene/Aluminum/Crosslinked Polyethylene);
3. PEX/AL/PEX (Crosslinked Polyethylene/Aluminum/Crosslinked Polyethylene).
The first is that the inner and outer layers are polyethylene, the second is that the inner layer is cross-linked polyethylene, the outer layer is polyethylene, the third is that the inner and outer layers are both cross-linked polyethylene, and the middle layer is aluminum.
This type of pipe, because of its aluminum layer, can increase the internal pressure resistance, block oxygen, CO2, etc. to avoid the threat of corrosion to water pipeline equipment, good thermal conductivity and reduce hot spot concentration, antistatic and good shielding and have a certain Therefore, it is easily accepted by the public. And because its connecting pipe fittings are made of copper, Meifeng plastic alloy pipe fittings, and stainless steel thread sealing pipe fittings, the connection is more convenient, no special tools are required, and it is close to the interface of a large number of cast iron pipes, which shows its certain advantages.
The second and third types of plastic parts are made of cross-linked polyethylene (PEX), which has a more stable intermolecular structure and is stronger than the first type, and is more suitable for building water supply and heating systems.
From the above comparison, it can be seen that these 5 kinds of plastic pipes that can be used for indoor cold and hot water supply have their own advantages and disadvantages. It is beneficial for hot water systems (such as floor heating systems with hot water pipes) because it can prevent the penetration of oxygen and avoid oxidative corrosion in the system. Other plastic pipes can also be used in several ways to make up for their poor oxygen barrier properties, so they can also be used in closed-loop hot water systems. In addition to the above five kinds of plastic pipes, plastic-lined steel pipes and pipe fittings, plastic-coated steel pipes and pipe fittings, plastic-clad copper pipes, plastic-lined aluminum pipes, etc., they can also be used in the field of indoor hot and cold water supply. These plastic-lined or plastic-coated metal pipes also have their own unique advantages and disadvantages. For example, the plastic-lined or plastic-coated steel pipe is based on galvanized steel pipe, and the reliability of its mechanical properties is most likely to be trusted by users. Therefore, at present, the above-mentioned various pipes are actually being used in the field of indoor cold and hot water supply at home and abroad, and they are constantly improving and developing. Aluminum-plastic composite pipes are developing rapidly in China, and the market share can be expanded accordingly in the future, but it cannot be inferred that aluminum-plastic composite pipes will become the mainstream of indoor water supply pipes. It can be predicted that the situation that various pipes compete for and share the indoor water supply pipe market will exist for a long time. In the field of indoor hot and cold water supply pipes, domestic manufacturers of the above-mentioned pipes have established production lines and put them into production.