When the raw water containing hardness ions passes through the resin layer in the exchanger, the calcium and magnesium ions in the water are replaced with the sodium ions adsorbed by the resin, and the resin adsorbs calcium and magnesium ions and the sodium ions enter the water, so that the exchanger The water flowing out inside is the softened water from which the hardness is removed.
Since the hardness of water is mainly formed and expressed by calcium and magnesium, cation exchange resin (softener) is generally used to displace Ca2+ and Mg2+ (the main component forming scale) in the water. With the increase of Ca2+ and Mg2+ in the resin, The efficiency of resin removal of Ca2+ and Mg2+ is gradually reduced.
When the resin absorbs a certain amount of calcium and magnesium ions, it must be regenerated. The regeneration process is to rinse the resin layer with the brine in the salt tank, and the hardness ions on the resin are replaced, and the resin is discharged with the recycled waste liquid. The softening exchange function is restored.
Since the hardness of water is mainly formed by calcium and magnesium, it is said that the hardness of water is mainly formed by calcium and magnesium and the principle of sodium ion exchange softening treatment is to pass the raw water through the sodium-type cation exchange resin, so that the hardness components Ca2+ and Mg2+ in the water are The Na+ phase in the resin is exchanged to adsorb Ca2+ and Mg2+ in the water to soften the water.
For example, if RNa stands for sodium type resin, the exchange process is as follows:
2RNa + Ca2+ = R2Ca + 2Na+
2RNa + Mg2+ = R2Mg + 2Na+
That is, after the water passes through the sodium ion exchanger, Ca+ and Mg+ in the water are replaced by Na+.
The general control valve operation process is: running, backwashing, salt absorption, slow washing, salt tank hydration, and washing.