Softening system

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. Water is softened water with the hardness removed.

 

Since the hardness of water is mainly formed and represented by calcium and magnesium, cation exchange resin (water softener) is generally used to replace Ca2+ and Mg2+ (the main components of scale formation) in the water. With the increase of Ca2+ and Mg2+ in the resin, The resin removal efficiency of Ca2+, Mg2+ gradually decreased.

 

After 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 salt water in the salt tank to replace the hardness ions on the resin. The softening swap function has been restored.

 

Since the hardness of water is mainly formed by calcium and magnesium and indicates that the hardness of water is mainly formed by calcium and magnesium and indicates that the principle of sodium ion exchange softening treatment is to pass the raw water through the sodium cation exchange resin, the hardness components Ca2+, Mg2+ in the water and The Na+ in the resin is exchanged, thereby adsorbing Ca2+ and Mg2+ in the water and softening the water. For example, the sodium resin is represented by RNA, and its exchange process is as follows:

 

2RNa + Ca2+ = R2Ca + 2Na+

 

2RNa + Mg2+ = R2Mg + 2Na+

 

That is, after the water passes through the sodium ion exchanger, the Ca+ and Mg+ in the water are replaced by Na+.

 

The general operation process of the control valve is: operation, backwashing, salt absorption, slow washing, water replenishment in the salt tank, and positive washing.

There are five processes: work (sometimes called water production, the same below), backwashing, salt absorption (regeneration), slow flushing (replacement), and fast flushing. All the processes of different softening water equipment are very close, but due to the difference of the actual process or the need for control, there may be some additional processes. Any water softening equipment based on sodium ion exchange is developed on the basis of these five processes (among them, the fully automatic softening water equipment will increase the brine re-injection process).

 

Backwashing: After working for a period of time, the equipment will intercept a lot of dirt brought by the raw water on the upper part of the resin. After these dirts are removed, the ion exchange resin can be fully exposed and the regeneration effect can be guaranteed. The backwash process is that water is washed in from the bottom of the resin and flows out from the top, so that the dirt intercepted by the top can be washed away. This process generally takes about 5-15 minutes.

 

Salt absorption (regeneration): the process of injecting brine into the resin tank. The traditional equipment uses a salt pump to inject the brine, and the fully automatic equipment uses a special built-in injector to inhale the brine (as long as the water has a certain pressure) . In the actual working process, the regeneration effect of brine flowing through the resin at a slower speed is better than the effect of simply soaking the resin with brine, so the softening water equipment is regenerated by the slow flow of brine through the resin. This process generally takes 30 minutes, the actual time is affected by the amount of salt used.

 

Slow flushing (replacement): After the brine flows through the resin, the process of slowly flushing all the salts in the resin with raw water at the same flow rate is called slow flushing, because there are still a large number of functional groups in this flushing process. Calcium and magnesium ions are exchanged with sodium ions. According to practical experience, this process is the main process of regeneration, so many people call this process replacement. This process is generally the same as the salt absorption time, that is, about 30 minutes.

 

Quick rinse: In order to thoroughly rinse the residual salt, the resin should be rinsed with raw water at a flow rate close to the actual work. The final effluent of this process should be soft water that meets the standard. Under normal circumstances, the fast flushing process is 5-15 minutes.