The equipment is for reducing the hardness of raw water .Raw water to be de-mineralized goes through the exchanger from bottom to up. The positive ions of magnesium and calcium are exchanged with sodium. Then the raw water becomes soft water containing very few ions of magnesium. The de-mineralized water can be used for boiler and some other industries. Due to the high dissolving ability of sodium ion in water, scale can hardly be formed in the boiler and can be easily removed. Water shall be filtered and clarified before coming into the exchanger. After being de-mineralized in the device, the water hardness will be less than 0.03ppm.