Hard water is water that contains mineral salts such as bicarbonate compounds, calcium ions, magnesium and others.
There are two types of water hardness: permanent and temporary
Hardness is mainly measured by the two metals calcium and magnesium. In general, the causes of cations are difficult. Ions such as aluminum, iron, manganese, and zinc are involved in water hardness, but calcium and magnesium are abundant, and other cations are either non-existent or very small. Total hardness is the sum of calcium and magnesium.
(Temporary difficulty – carbonate difficulty)
Harmful hard water
Despite the benefits of hard water, excessive water hardness is also harmful. One of the disadvantages is that drinking too much hard water causes sedimentation in stonemasons and also causes gastrointestinal diseases, especially kidney stones.
Therefore, it is more recommended to use light water for drinking and to get the magnesium and calcium needed by the body from food or vegetables and fruits.
Hard water causes the drinks to lose their flavor. Delayed cooking and hardening of beans with hard water are other side effects. In addition, hard water damages the walls of the boilers, causing corrosion and creating a calcareous layer on the walls of the boilers and related facilities. Not lathering well is another side effect of water hardness that increases soap consumption.
Adverse effects of water hardness
۱- Reducing the effectiveness of active ions in washing
۲- Leaving the sediments as stains on the dishes and clouding the dishes
۳- Increasing the volume of sediments on heat and mechanical generators and sprinkler nozzles
۴- Increasing the consumption of detergents and increasing the energy consumption exponentially
Soften hard water
Hard water can be softened in three ways:
۱- Decomposition method
۲- Method of settling
۳- Ion exchange method
The practice of reducing the hardness of calcium and magnesium and water-soluble iron oxide is called softening water …
Ion exchange resin or ion converter
Hardeners, or water softeners in the dishwasher, are generally dependent on an ion exchange resin or ion converter, which replaces calcium and magnesium hardening ions, instead of sodium ions …
These resins belong to the group of polymer resins and are called minerals called zeolins.
How does a water softener work?
The incoming water passes through the resin through the bed, the resin has a negative charge, and the negative charge of the resin causes the absorption and trapping of calcium and magnesium hardness with a positive charge in the water. Resins initially contain hydrogen and sodium or potassium monovalent ions, which are replaced by water-soluble calcium and magnesium bicarbonate ions.
The harder the water, the more rigid the system releases more hydrogen, sodium or potassium ions into the water.
After a period of use and passage of hard water through the resins, the resins that previously had a negative charge are covered with positively charged ions, which reduces the softening effect (hardness acceptance) of the resins. So you have to clean them again and return them to the hardening cycle. In simpler terms, the calcium and magnesium that now covers the resins are removed from the resins … Reconstruction of the resins will be possible by passing a saline solution, usually a solution of sodium chloride or hydrochloric acid, through the resins.
Hardness system tank
The rigidity system has two main reservoirs:
The connection between these two tanks is made through an internal pipe, and this connection is made by a valve that is opened and closed under pressure.
When the water in the back of the bumper enters the salt tank, due to the pressure of the water (gravity of the gravity on the water behind the bumper), the communication valve between the two tanks opens and the salt solution enters the resin tank.
After draining the water and running out of water behind the bumper, now that there is no pressure behind the connection valve between the tanks, the valve was closed.
When the solenoid valve of the salt tank is cut off, the water and salt solution remains in the resin tank and the resins are immersed in it until the next stage of use.
Water softener / hardener in the dishwasher
The operation of the dishwasher hardener system is based on the ion exchange process.
This ion exchange takes place very quickly, just enough incoming water to come in contact with the resins.
Calcium and magnesium ions in city water are absorbed by the resin grains and taken from the water, while they are replaced by sodium ions.
Hardening operations occur every time water enters the device. Each time the Aquastap opens and water enters the device, the hardening system enters the hardening stage.
Description of the science of water softening / hardening system
After passing through the aerobics, the incoming water enters the salt / chamber reservoir and overflows after passing through the aerobics and flows into the resin tank. The ion exchange takes place and the water becomes soft.
From here, the water continues its way to the wash / samp tank and enters the wash cycle until the water intake level reaches the level where the hydrostat commands the power outage.
To complete the proper water hardening process, the salt tank must be rinsed at the beginning of each step with a salt solution to remove impurities.
The water in the resin tank, which now contains alkaline salts (calcium, magnesium) and sodium chloride, must be cleaned before the water inlet, and to ensure that the solution does not come into contact with the dishes, there are two steps (dewatering and draining). It is necessary at the same time.
At this stage, two water entry and exit operations will be performed simultaneously. When the Aqua Stop is electrified, water flows through the resin tank and from there to the pelvis, and when the discharge pump is electrified