1️⃣ Basic Control Structure of an Industrial Gas Burner

A typical system includes:

• Gas train

  • Manual shut-off valve

  • Gas filter

  • Gas pressure regulator

  • Safety solenoid valves

  • Gas proportional control valve

• Air system

  • Combustion air fan

  • Air damper (manual or motorized)

• Control system

  • Ignition transformer

  • Flame detector (UV or ionization)

  • Burner controller (PLC or burner management system)

  • Temperature or pressure controller

2️⃣ Main Control Methods

🔹 A. On/Off Control (Single-stage)

• Burner runs at full capacity or stops.

• Used in small boilers or ovens.

• Controlled by temperature or pressure switch.

Simple but not energy-efficient.

🔹 B. High/Low (Two-stage) Control

• Low fire during standby

• High fire when load increases

• Controlled by thermostat or pressure controller

More stable than single-stage.

🔹 C. Modulating Control (Best Performance)

Most modern industrial systems use modulating control.

How it works:

• A temperature controller (PID) sends signal (4–20 mA or 0–10 V)

• Gas proportional valve adjusts gas flow

• Air damper motor adjusts air simultaneously

• Maintain correct air-fuel ratio

This provides:

• Stable flame

• Energy saving

• Precise temperature control

3️⃣ Key Control Parameters

✅ 1. Gas Pressure Control

• Use proper gas regulator

• Maintain stable inlet pressure

✅ 2. Air-Fuel Ratio Control

Too much air → low efficiency
Too little air → incomplete combustion

Best practice:

• Slight excess air (O₂ 3–5% in flue gas)

✅ 3. Flame Safety Control

Must include:

• Dual solenoid valves

• Flame detection

• Automatic shutoff if flame failure

Standards are usually based on:

• NFPA (USA)

• EN standards in Europe

Since you are in Germany, systems normally follow EN 746-2 (Industrial Thermoprocessing Equipment – Safety Requirements).

4️⃣ Typical Control Sequence (Automatic Burner)

1. Pre-purge (fan runs to clear gas)

2. Ignition spark

3. Pilot gas opens

4. Flame detected

5. Main gas opens

6. Modulation control

7. Shutdown when temperature reached

5️⃣ Advanced Control (For Better Performance)

• Oxygen trim control (O₂ sensor feedback)

• VFD fan speed control

• PLC + HMI monitoring

• Combustion analyzer adjustment

6️⃣ Common Control Problems