Pyronics Single Tunnel/Multiple Tunnel Nozzle Mix Burners are designed for extremely wide turndown ranges. Gas and air are mixed only at the point of discharge, flashback is prevented.

Exclusive stepped tunnel design creates very high turbulence and internal recirculation in the flame. The combustion tunnel shape produces pressures in the flame that are lower than the furnace pressure aiding flame retention.

Ignition of main flame is smooth and stable in all sizes. Hot refractory surfaces on the blocks are not required for ignition. All sizes may be lighted and raised immediately to high fire with excellent flame stablility.

Each burner is equipped with an integral mounting flange for pressurized firing up to 10 psig furnace pressure (consult factory).

NM burners develop capacity ratings at low pressure drops. Economical low pressure air blowers are adequate.

Flanged connections are standard. Pipe unions are normally not required.

Flame lengths are very short (see capacity table). Large combustion chambers are not required. When operating in air heaters flame shield block extensions are used to prevent flame quenching.

Multiple tunnel units produce higher capacities with short flame lengths by spreading the flame over a large area. Cross ignition ports between tunnels are provided to stabilize the flames at normal firing rates and fuel-air ratios. Individual pilots are recommended for each tunnel with main flame supervision.

Each NM burner can be ordered with a micrometer type gas flow adjuster. Pressure referenced control systems are used to control heat inputs.


  • Forging Furnaces
  • Air Heaters
  • Annealing Furnaces
  • Fume Destructors
  • Melting Furnaces
  • Ovens
  • Dryers
  • Malleabilizing Furnaces
  • Incinerators
  • Crematoriums
  • Ladle Heating
  • Curing Ovens
  • Burn Out Furnaces
  • Steam Generators


Features and Benefits

  • High heat inputs – intense combustion
  • Excellent flame stability
  • Wide turndown range – greater than 10:1 on single tunnel burners, higher turndown with multiple tunnels
  • Flanged construction – eliminates pipe unions
  • High flame velocities for better furnace circulation
  • Short flame lengths – less than 1 ft. per million BTU/hr when firing into an air stream
  • Designed for pressurized firing
  • Precision pilot and flame detection mountings
  • Unique stepped tunnel design
  • Will burn at high fire with cold block – no warm up required
  • Lower air pressures required
  • No flashbacks
  • Refractory burner blocks for operation up to 3300°F
  • Rugged heavy duty construction