Multi-layer composite pipe
Multi-layer composite pipes are pipes that are made up of different materials. Multi-layer composite pipes with an aluminum core are widely used. The aluminum core is surrounded on both sides by means of an adhesive layer, for example cross-linked polyethylene (PE-XE). Such pipes are available with an outer diameter of 14, 16, up to 110 mm, the wall thickness reaches 2 to 10 mm, depending on the manufacturer and dimension.
processing
In contrast to pure plastic pipes, the multilayer composite pipes are very easy to bend. The aluminum intermediate layer makes the pipes impermeable to oxygen , among other things ; thus there is no oxygen entry into the heating water and no water-side corrosion in unprotected steel parts such as radiators and boilers . The pipes are dimensionally stable, have a low weight, are easy to lay and are suitable for almost all types of installations , such as heating, plumbing, thermoactive component activation, floor and wall heating, compressed air supply, industrial pipeline construction and, since 2008, also for gas supply.
There are press -, plug, screw and sliding sleeve technique used. For the former, you need special pliers to achieve the required pressing pressure and the pressing contour intended for the system. The screw and plug connections, on the other hand, are available in detachable and non-detachable versions. Since the tools required for pressing and sliding sleeve technology are quite expensive, screw connections can be an inexpensive solution in the amateur sector. However, the specialist often relies on the press connection because it enables them to work faster and more economically.
Flow resistance of the pipes and fittings
The pressure loss along the lines through which there is a flow is comparable to copper pipes with the same inside diameter. Due to the construction of the fittings (tapering), however, there is an increased pressure loss in the fittings compared to copper pipe fittings.
There are probably some manufacturers who get by without tapering the fittings. With sliding sleeve systems, this is achieved by expanding the pipe before assembly.
As a rough estimate, manufacturers can specify a corresponding pipe length for the pressure loss in the respective fitting, which must be added to the actual pipe length for each fitting in order to approximately determine the real pressure loss. Example: a pipe with an inside diameter of 20 mm and a length of 3 m plus an elbow and two connecting sleeves. 3 m (pipe) + 1.3 m (socket) + 1.3 m (knee) + 1.3 m (socket) = 6.9 m. Thus, for example, when installing with short pipe lengths, the pressure loss is approximately doubled compared to copper pipes.
durability
So far there is no empirical data on how many years such systems are leak-proof, as they have only been in use since 1990. On the other hand, the speed of processing and the flexibility of laying are the great advantages of these pipes.
Norms and standards
- DIN 16836 - Multi-layer composite pipes - Polyolefin-aluminum composite pipes - General requirements and tests
- DIN 16837 - Multi-layer composite pipes - Multi-layer plastic composite pipes - General requirements and tests
Web links
Individual evidence
- ↑ Archived copy ( memento of the original from March 6, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 1.4 MB) data sheet
