■ Due to the secondary pollution of cast iron water meters, the mandatory water meter safety rules require that iron-shell water meters made of gray cast iron be eliminated in 20 10. For large-caliber water meters, gray cast iron will be replaced by ductile iron.
■ All parts in the water meter that come into contact with water should be made of materials that are generally considered non-toxic, non-polluting and non-bioactive, and should be resistant to internal and external corrosion.
■ The main producing area of molten iron watchcase is Linyi, Shandong.
2, copper shell water meter
■ When the voice of phasing out cast iron water meters is getting louder and louder, the international copper price is still at a low level, and some manufacturers choose to use brass instead of cast iron to make water meter shells.
■ Subsequently, the increase in copper price led to the high price of copper-clad water meters, which were easily stolen when installed outdoors. The trend of using brass instead of cast iron to make water meter housing has not formed a climate.
■ China is a country lacking in copper resources, and copper smelting needs a lot of energy, which is inconsistent with the policy of energy conservation and emission reduction.
■ Brass is a product of copper and lead, and its copper rust is far more toxic than cast iron rust. Therefore, the use of brass can not solve the problem of secondary pollution.
■ The copper water case is mainly produced in yingtan, Jiangxi, and is mainly used for supporting prepaid water meters.
3, aluminum alloy shell water meter
■ Aluminum alloy adopts die casting process, with obvious forming characteristics and beautiful appearance.
■ Aluminum alloy materials containing trace elements can resist external pollution and will not pollute water internally.
■ The product strength meets the physical strength requirements for manufacturing water meter housing and its accessories.
■ Manufacturers with excellent quality and productization:
Beijing intelligent water meter factory
. The price is still relatively expensive, and it is only suitable for high-end products for the time being.
4, plastic shell water meter
■ The industry is developing plastic water meters suitable for domestic demand and formulating product standards.
■ Plastic water meters can not only solve the problems of secondary pollution of cast iron water meters and high price of copper-clad water meters, but also prevent copper pieces installed outdoors from being stolen.
■ The manufacturing process of plastic shell water meter can fully reflect energy conservation and environmental protection, and conform to the national energy conservation and emission reduction policies.
4. 1 nylon material
■ Nylon shell water meter is the first choice material for plastic water meter in recent years. In 2007, Ningbo Water Meter Company exported more than 200,000 water meters to Malaysia alone.
■ Nylon plastic shell water meter has withstood the test of various conditions in international and domestic markets.
■ Nylon materials are basically divided into three grades: Swiss aromatic nylon (6T/6I), German BASF glass fiber nylon (PA66) and domestic modified glass fiber (PA6).
■ The advantages of nylon shell water meter are sanitation, anti-theft and cheapness. As long as the materials are properly selected, its strength, aging resistance and creep resistance can meet the normal needs of water meters.
■ However, it is difficult to distinguish the performance of a black water meter because the market price of nylon raw materials is very different. Once there is a quality problem in a few years, it may break out.
■ The possible problem of nylon shell is aging after ultraviolet irradiation, so the testing means and technical strength of water meter suppliers are very important.
■ When nylon absorbs water in water, its strength will obviously decrease and its toughness will increase, and its strength is only 60% of that in dry state. The strength of nylon is mainly achieved by adding glass fiber. The more glass fibers in a good nylon material, the more expensive it is, while the more glass fibers in a poor nylon material, the cheaper it is.
■ Manufacturer with high quality and mass production: Beijing Smart Water Meter Factory. The cost of plastic casing is several yuan higher than that of cast iron casing.
4.2 GSG polymer materials
■ GSG polymer materials have been operating under pressure for 25 years and are widely used in water supply industry. Practice has proved that they have strong ultraviolet resistance, good toughness and high physical strength.
■ GSG material is non-toxic and has no secondary pollution. In the past 25 years, there have been no reports of health problems caused by the use of GSG materials. The molding characteristics are good, and the Vicat point reaches 75 degrees. There is no phenomenon that the strength of nylon material decreases after water absorption.
■ Only in China.
Beijing intelligent water meter factory
Using GSG polymer material to make water meter shell, the pressure resistance exceeds 2.5MPa, and the price is the same as that of cast iron water shell.
4.3 Other plastic materials
■ ABS material: the price is cheap, and the preliminary test is qualified, but the anti-ultraviolet aging ability is extremely weak, especially for outdoor use, cracking and water leakage may occur.
■ PP0 material: superior performance, but expensive.
■ PPR material: widely used in tap water pipes, it is a good material for making water meter shells, but its shrinkage rate is difficult to control and it is not suitable for precision injection molding.
■ Reinforced polypropylene: cheap, but poor anti-ultraviolet aging ability, not suitable for outdoor use.
Cheap nylon material: the price is cheaper than that of iron-clad water meter, and the initial inspection is also qualified, which is only a temporary result on the surface. The reason is simple: the strength of wet nylon is only 60% of that of dry nylon, and a few minutes of water meter testing can't find any problems.