1. A _________ in a boiler is used to put off a fire in the furnace when the level of water falls to the unsafe limit. 2. An equivalent evaporation of a boiler is defined as _________. 3. The draught...

1. A _________ in a boiler is used to put off a fire in the furnace when the level of water falls to the unsafe limit.

2. An equivalent evaporation of a boiler is defined as _________.

3. The draught in the locomotive boiler is produced by _________.