| A boiler is used for generating steam. It does this by | | | | These scales are very damaging to the boiler |
| heatingwater to its boiling point, after which steam | | | | because theyinterfere with the heat transfer and can |
| will evaporatefrom it. | | | | lead to overheatingand eventually, boiler rupture. |
| When you boil a kettle of water, you will shut off | | | | Soft water is water that contains very little calcium |
| the fireor electric power when the water comes to a | | | | ormagnesium salts. They are used to feed the boilers. |
| boil. | | | | However,they tend to be acidic in nature. |
| No so with a steam boiler. Generation of steam is a | | | | Acidic water tends to corrode. This is not good for |
| continuousprocess. Once a boiler is generating steam, | | | | the boiler. |
| it may take quitea long while before it is stopped. | | | | Corrosion can weaken the boiler. |
| When steam is evaporatedfrom the water, new | | | | By treating the boiler water with chemicals, we can |
| water has to be added in to replace thewater given | | | | controlthe acidity of the water as well as the |
| out. | | | | softness of the water. |
| As more and more steam is evaporated, the water | | | | This will solve the problem with scales and corrosion, |
| becomes moreand more concentrated with salts and | | | | but itis not the ultimate cure-all. |
| other impurities. If youuse your kettle for a long | | | | The boiler water will continue to become more and |
| while, you will see some chalkydeposits inside it. | | | | moreconcentrated as the steam evaporates. The |
| The fresh water supplied to replenish those lost | | | | next step to takeis to remove the concentrated |
| throughevaporation cannot be pure and free from | | | | water and replenish it withfresh, soft water. |
| salts. Even minutequantities of salt in the water will | | | | The process of removing the concentrated water is |
| eventually become soconcentrated as to form scales | | | | calledblow-down. |
| or deposits. The deposits areusually calcium or | | | | Folks, close your ears! |
| magnesium salts. | | | | Until next time... |