Safety Interlocks in Boilers

Safety Interlocks in Boilers

Many of the intrelocks related to the start-up, shutdown, and operation of a boiler are implemented for the purposes of protecting personnel and equipment. Thay can be classified as either burner management to cumbustion control.

Safety interlocks in boilers

  • Public interlocks
  • Low air flow interlocks or fan interlocks 
  • Low fuel supply interlocks 
  • Loss flame interlocks 
  • fan interlocks 
  • Low water interlocks 
  • High combustibles interlock 

Public interlock

Prevents fuel from being admitted to an unfired furnace until the furnace has been throughly air purged

Low air flow interlocks or fan interlock

Fuel is shut off upon loss of air flow or combustion air fan and blower

Low fuel supply interlock
Fuel is shut off upon loss of fuel supply that would otherwise result is unstable flame conditions.

Loss flame interlock

All fuel is shut off upon loss of flame in the furnace, or fuel to an individual burner is shut off upon loss of flame to the burner 

fan interlock

Stops forced draft upon loss of induced draft fan 

Low water interlock

Shuts off fuel on low water level in boiler drum

High combustibles interlock

shuts off fuel on highly combustible content in the flue gases  

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