The concentration of undesirable solids in boiler water can be reduced through the use of a continuous purge or blowdown system. A blowdown tank receives continuous blowdown from the steam drum and blowdowns of variable temperatures and pressures from the steam generator. A blowdown tank can also function as a gravity feed drain for the steam generator when the generator is drained for maintenance.
Good boiler blowdown practices can greatly reduce a boiler's water treatment needs and operation costs. Combustible mixtures left in a boiler due to improper purges, however, have been known to cause catastrophic explosions. Proper tank level controls are essential to ensure a safe and effective boiler blowdown system.