Page 90 - Boiler plant and distribution system optimization manual
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The Control of Boilers 75
SAFETY VALVES FLAME SAFETY CONTROLS
The purpose of safety controls is to prevent Flame safety controls continuously monitor
explosions. Safety devices are installed for the the pilot and main flame zone to detect the un-
pressure vessel which usually consists of safety interrupted presence of the flame (Figure 8.2). If
valves sized to carry away steam faster than it can unburned fuel is allowed to accumulate in the
be generated by the boiler in the event an over boiler there could be an explosion, so this system
pressure situation exists. This is a mechanical must have the capability to shut down the fuel
system consisting of safety valves and exhaust system almost immediately. These systems were
piping to vent the escaping steam harmlessly developed from studying lessons learned from
through the roof. boiler explosions and disasters over the years.
Boiler controls also sense overpressure and Flame safety controls are designed to shut
override the main control system and shut off the off the fuel to prevent explosions that can occur
flow of fuel to the boiler. when:
Figure 8.2—Flame safety diagram showing safety shut off valves
