What is foaming & priming?

Foaming: It is the formation of thick layer of steam bubbles on the top of the water surface inside the boiler due to:

1. High concentration of impurities.

2. By the animal or vegetable fats in feed water carry over from the oil heaters.

3. Increase in level of dissolved & suspended solid TDS level.

4. Increase in water level.

            To prevent foaming, surface or scum blow down should done frequently to expel any floating impurities for the boiler and no lube oil should be allowed to enter the boiler.

     Priming: It is condition in which large amount of water are carried along with the steam into the steam line.

      It is caused by –

1. Excessive foaming

2. Improper amount of steam space

3. By a sudden rush of steam such as is produced when steam stop valve is suddenly opened.

To prevent priming, never keep the water level too high.

Open steam stop valve slowly.