Water purifiers, also known as water purifiers, are mainly divided into three categories according to water purification methods:
1, reverse osmosis (RO) water purifier is a kind of water purifier that uses reverse osmosis membrane to filter tap water. Permeation is transferred from high concentration to low concentration, and reverse osmosis is transferred from low concentration to high concentration. The water from RO water purifier is pure water with high concentration, and all substances except water molecules are removed. Because it is transferred from low concentration to high concentration, it needs energy-it takes 24 hours to energize the motor. Because the instantaneous filtered water volume of RO membrane is very low (the membrane pore of RO membrane is only 0.00 1 micron), the standard of pure water output is 1: 3, that is, 4 liters of water produces 1 liter of pure water, so it is necessary to connect a water storage tank to supply water to the water storage tank under pressure when using water. At present, there are many factories making RO water machines in China, such as Jianite in Shanghai and Qinyuan in Zhejiang, and there are also many parts factories specializing in producing membranes and motors, resulting in too many manual workshops, self-assembly, uneven quality and need to be standardized.
2. Ultrafiltration water machine is a water machine that uses ultrafiltration membrane to filter water. Ultrafiltration membrane is an improvement on RO membrane, because the pore size of RO membrane is only 0.00 1 micron, and the effluent is too pure, which removes harmful substances in water and beneficial minerals and trace elements. Ultrafiltration membrane enlarges the pore size to 0.0 1 micron, allowing some minerals and trace elements beneficial to human body to pass through. However, at present, the representative factory in China is Li Sheng. However, after the pore size of ultrafiltration membrane is increased, some compound molecules, heavy metals and chlorine in water cannot be intercepted, and the process still needs to be improved.
3. Multi-media water purifier is a water machine that uses different media to filter different pollutants in water. The media are basically: PP cotton+activated carbon, etc. PP cotton is used to filter large particles of sediment and rust in water, and activated carbon is used for adsorption. Advanced multi-media water purifier will add several media, such as KDF and gold media, which can remove fertilizers, pesticides, pesticides and chlorine in water; The advantage of multi-media water purifier is that it can filter harmful substances in water, while retaining minerals and trace elements beneficial to human body. At present, the multimedia water purifiers in the domestic market are mainly occupied by American brands: Pintel, Pais, Aihewlett-Packard, etc. And many of them have set up factories in China. Although the multi-media water purifier has obvious advantages, its service life is limited by the adsorption capacity of filter media, so the later maintenance cost is high.
In addition to the above three types of products, there is also a central prefilter-a primary filter installed in domestic water pipes, which mainly filters suspended solids such as sediment and rust in water to protect water pipes and water appliances; There is also a kind of water softener, which removes the scale, so that the water will not produce scale after heating. It is used to protect hot water appliances such as water heaters and floor heating, and at the same time, it can improve the texture of water, so that bathing and laundry also have obvious good effects. The working principles of water softeners in the market mainly include (1) scaling by chemicals such as polyphosphate, such as many scale inhibitors in the market, and (2) calcium extraction and laundry by electromagnetism. (3) Ion exchange water softener is the most mainstream water softener in the market at present. Its principle is to replace calcium and magnesium ions in water with sodium ions, which is much better than the first two, but it also has some small defects. (4) The nano-crystal salt-free water softener newly developed by Pais in the United States does not need salt or electricity. Its principle is that calcium, magnesium and bicarbonate ions in water are wrapped into crystals that will not scale by relying on the nuclei on high-energy polymer spheres.