12 Jul 2024
How to choose pure water equipment cartridge filter&activated carbon filter? And how to maintain the filter？
1.Cartridge filter
The size of the filter varies according to the amount of water filtered. The most common are sand filters, non-woven filters, and PP fiber filters. The lengths of non-woven filters and PP fiber filters are 10 inches and 20 inches. In both cases, the diameter of the filter element used as a filter should generally be about 25u.
The function of the coarse filter is to remove suspended impurities of large particle size in the water, prevent these impurities from entering the activated carbon filter and covering the surface of the activated carbon, so that the capillary structure of the activated carbon loses the ability to adsorb impurities in the water.
As the retained solid impurities increase, the coarse filter increases sharply, and the water flow gradually decreases. If not handled in time, the water flow requirements of the subsequent treatment process cannot be met. For sand filters, the pressure should be backwashed in time after rising to a certain level. During the backwashing process, some fine sand is flushed out of the filter, so sand should be added to the sand filter regularly. After repeated backwashing, the degree of crushing increases, and each backwash cannot be 100% washed. The remaining silt in the sand gradually increases, and the sand layer seems to be "knotted". At this time, the sand layer should be replaced. For non-woven fabric or PP fiber filter cartridges, it is usually difficult to flush water after the filter holes are blocked. The filter element must be replaced regularly.
2.Activated carbon filter
The main function of the activated carbon filter is to remove macromolecular organic matter, iron oxide and residual chlorine. Organic matter, residual chlorine and iron oxide are easily poisoned by ion exchange resins, while residual chlorine and cationic surfactants not only poison the resin, but also destroy the membrane structure and make the reverse osmosis membrane ineffective.
The activated carbon filter uses the rich capillary pores of activated carbon to adsorb and filter macromolecular organic matter, residual chlorine, iron oxide and other colloids in the water. This adsorption is irreversible, that is, the activated carbon has a certain saturated adsorption capacity. After adsorption saturation, the activated carbon loses its adsorption properties and cannot be washed away by backwashing. In addition, after the activated carbon adsorbs organic matter, it provides rich nutrition for bacteria, allowing bacteria to multiply in the activated carbon filter, and the microbial content in the water is increased by activated carbon filtration.
Backwashing is performed regularly before the activated carbon is saturated to remove a large number of bacterial colonies and suspended solids on the surface of the activated carbon. After the activated carbon adsorption is saturated, new activated carbon should be replaced immediately, otherwise it will cause irreparable damage to the reverse osmosis membrane.
3.Water softener
The function of the water softener is to remove calcium and magnesium ions from water and soften the water. If there is no water softener or the water softener fails, calcium and magnesium salts will form water-soluble precipitates on the surface of the reverse osmosis membrane due to the sharp increase in concentration, thereby blocking the pores of the reverse osmosis membrane and shortening the service life of the reverse osmosis membrane.
The water softener used for pure water is usually a sodium-type cation exchange resin, and the resin is exchanged and saturated, and then regenerated with salt. After several years of use, the degree of resin breakage becomes more and more serious, and the softening ability is gradually lost. Especially when the activated carbon filter is saturated and the activated carbon is not replaced in time, the iron, organic matter and residual chlorine in the raw water will directly enter the water softener, causing resin poisoning. Once the resin is poisoned, it cannot be regenerated by regeneration. When the working exchange capacity of the resin is significantly reduced, the resin should be replaced.
Reverse osmosis is the core component of the pure water system. Raw water that has been pretreated and meets the requirements of the reverse osmosis membrane is reverse osmosis.
Doing a good job of maintaining reverse osmosis is the key to ensuring pure water quality. The salt concentration on the membrane surface during the working process of the reverse osmosis membrane is higher than the salt concentration of the bulk fluid. This phenomenon is called concentration polarization. The result of concentration polarization is the precipitation of some salt.
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