Since the solar water heater is installed outdoors, it is recommended to use aluminum-plastic pipes.
1. The low temperature resistance of aluminum-plastic pipes is higher than that of PPR pipes. PR is fragile when cold (the fragility point is -20°C), special care is therefore required during construction in winter (below 5°C). Aluminum-plastic pipes have no cold brittleness (the brittle point is -70°C) and can be easily installed below -20°C.
2. The expansion coefficient of PPR pipes is high. Since the piping system is rigid and straight, the PPR pipe itself cannot digest the deformation, so it is easy to cause bending, deformation and leakage of the piping system. Aluminum pipes are made of aluminum. Taken together, their linear expansion coefficient with aluminum is approximately 0.025 mm/m.
The temperature is ℃, which is 1/6 of the PPR pipe. Affected by temperature changes, the deformation is small, while the aluminum pipe is a flexible coil. The hose itself can absorb a certain amount. deformation and will not cause thermal deformation of the piping system.
3. PPR pipe has poor aging resistance. The PPR molecular chain structure - (-CH2—CH-)n- contains a large number of unstable tertiary carbon atoms, which are more sensitive to CH3 light and oxygen. , and impurities (such as copper, iron ions) and aging. Therefore, the PPR product manual generally stipulates that the open air stacking time should not exceed six months.
PE plastic used in aluminum-plastic composite pipes has a molecular chain structure - (-CH2-CH2-)n-, which is the most stable structure among plastics, and the layer d aluminumMinium in the middle of the aluminum-plastic pipe insulates the inner and outer layers, the outer plastic layer can add sufficient stabilizers to resist aging by light and oxygen without affecting the hygiene of the inner layer that comes into play. contact with water.
Detailed information:
The advantages of aluminum-plastic pipes can be summarized in the following three aspects:
1. Excellent hygienic performance: the outer layer made of aluminum-plastic. Plastic pipes are made from a special polyethylene material, which is clean and non-toxic. More importantly, the middle layer of the tube is made of aluminum, which not only insulates light but also blocks oxygen. It is well known that the environment in which microorganisms grow borncessation of light oxygen. The aluminum interlayer of aluminum pipes will eliminate the growth of microorganisms and algae that plastic pipes cannot reach.
Not only do plastic pipes contain high amounts of antioxidants, which prevent material degradation, but when the antioxidants are extracted from the water held in the pipes, they can also cause water pollution. the water. In addition, because there is no photoresistant material in the entire plastic pipe, microorganisms are easily generated, causing secondary pollution of water quality.
2. Excellent high and low temperature resistance: the long-term use temperature is 95°C (50 years, IMPa), the maximum use temperature is 110°C, and the aluminum plastic pipe has a low coefficient of thermal expansion. . It is equivalent to the thermal expansion coefficient de aluminum and only one sixth of the total number of plastic pipes. When the temperature changes, the deformation is very small and the aluminum plastic pipe is a flexible coil. The pipe itself can absorb a certain amount of deformation and will not cause thermal expansion deformation of the piping system.
The whole plastic pipe has poor high and low temperature resistance. Long-term use of PPRThe temperature is only 70 degrees (50 years, IMPa) and the maximum operating temperature is 95 degrees. At the same time, the expansion coefficient of PPR pipes is high, and when the external water temperature (hot and cold water) changes, a large initial deformation occurs. Since PPR pipes are straight and rigid pipes, they cannot absorb deformation, which can easily lead to bending, deformation or even leakage of the system.stem.
3. Long service life: PE plastic multi-tube aluminum mold, the molecular chain structure (CH2 - CH2 -) used is relatively stable in the plastic, and. As an insulation layer between the inner and outer aluminum layers of the tube, plastic can be added to the outer layer to repel light stabilizers and oxygen aging without affecting the hygiene of the internal contact with water, thus improving its anti-aging performance.
4-6 points.
The water lines of solar water heaters have 4 and 6 point pipes. Most of them are 4 point pipes. They are now talking about diameter, which is diameter 16, and the diameter of the PPR. is 20. When installing, the appropriate one should be selected according to the size of the water outlet pipes to be installed.