It is well known that hot water boilers are prone to accumulate scale after long-term use; the scale in the boiler needs to be removed in time to prevent accidents. Common boiler descaling methods are: mechanical descaling, pickling descaling, and alkaline boiling descaling.
1. Mechanical descaling method: When there is loose scale and slag in the cast iron hot water boiler, after stopping the furnace, cool the cast iron hot water boiler, drain the boiler water, rinse with clean water, and use a flat shovel, wire brush, and motorized tube grinder to descale.
This method is relatively simple and is mostly used for small cast iron hot water boilers with simple scaling. However, the labor intensity is high, the descaling effect is poor, and the boiler body is easily damaged.
2. Pickling descaling method: The pickling descaling method mostly uses hydrochloric acid or nitric acid for cleaning. The pickling solution is composed of hydrochloric acid plus corrosion inhibitor or nitric acid plus corrosion inhibitor.
This pickling solution can not only remove the scale in the boiler (hydrofluoric acid needs to be added when removing nitrate scale), but also basically does not corrode the cast iron hot water boiler. Pickling descaling has the effects of dissolving, peeling and loosening.
3. Alkali boiling descaling method: The descaling effect of alkali boiling descaling method is worse than that of pickling descaling method, but the scale is looser after alkali boiling. Therefore, for scale that is difficult to remove with hydrochloric acid, alkali boiling method can also be used for pretreatment before pickling.
The alkali boiling method is simple to operate and has relatively few side effects. The disadvantages are that the boiling time is long, the reagent consumption is large, and the effect is poor.
