Flame Detector

A Flame Detector (or Flame Sensor) is a safety device that verifies the presence of a flame in a burner. If the flame fails, the detector signals the Burner Controller to immediately cut off the fuel supply.

Working Principle

Flame detectors work by sensing specific characteristics of a flame that distinguish it from background heat or light. The goal is to prevent "flame-out" conditions where fuel continues to flow without burning, creating an explosion hazard.

Common Types

1. Ionization Rod (Rectification)

• Mechanism: Uses the principle that a flame can conduct a small electrical current (rectification). A metal rod is placed in the flame.
• Application: Small gas burners, pilot flames.
• Pros: Simple, inexpensive.
• Cons: Rod can degrade over time; not suitable for oil.

2. UV Scanner (Ultraviolet)

• Mechanism: Detects the UV radiation emitted by the combustion process.
• Application: Gas and light oil burners.
• Pros: Fast response, compact.
• Cons: Can be blinded by smoke; sensitive to spark ignition (must distinguish spark from flame).

3. IR Scanner (Infrared)

• Mechanism: Detects the flickering frequency of infrared radiation from the flame.
• Application: Heavy oil, coal, and low-NOx gas burners where UV signal is weak.
• Pros: Can see through some smoke/dust.
• Cons: More complex setup.