Project Description

Air-cooled oil guns are developed to replace the high maintenance cost and cumbersome oil gun retract mechanism.


The air-cooled oil gun is cooled by a low-pressure stream of air passing through a specially designed gun cap with a finned surface. The low-pressure air passing around the atomizer shields and reduce the furnace radiation falling on the atomizer parts by extracting heat through the finned surfaces.


  • Air cooling of critical atomizer parts is more efficient than retract of oil guns in the wind box
  • An oil gun located in a high radiant temperature zone makes its atomizers continuously exposed to overheating and gets damaged.
  • To prevent this condition and protect the oil gun, pneumatic retraction of the oil gun is the method. But it presents its own operation and maintenance difficulties
  • To avoid the retract mechanism CCE & CE offers an Air-cooled Design where the oil guns remain inserted in the firing position when not in use without damage to any of its components.
  • CCE & CE Oil gun eliminates the complicated retract mechanism, their maintenance problems and also provides improved accessibility to the burner front.
  • CCE & CE Oil gun is the best alternative to retractable oil guns and meets the required safety and code requirements

Cooling air requirement

  • Standard Capacity Guns 2 – 2.5 sm3/min of ambient air at 50 – 60mm WC above furnace pressure
  • High Capacity Guns 4 – 4.5 sm3/min of ambient air at 80 – 100 mm WC. above furnace pressure

The purpose of the air-cooled oil guns is to eliminate the more expensive and cumbersome retract mechanism prone to increased maintenance with retract air cylinders, solenoid valves, limit switches, and electrical connections


To prevent the oil gun tips from getting overheated when oil guns are not in use, they are automatically withdrawn to a relatively cooler place inside the wind box by retracting mechanism. Pneumatically operated retract mechanisms comprising of solenoid valves, limit switches, air cylinders, etc are presently used to retract oil guns from normal firing positions when the oil guns are not in service.

Reliability of operation of the retract mechanism at higher ambient temperature and dust conditions very close to the burner zone require special care and high maintenance. Due to various reasons frequent failure of the oil gun retract mechanisms have been observed.

As a result, the oil guns are left in a firing positions even when not in operation. Constant exposure to heat can cause rapid heating of the tip and followed by rapid cooling by the fuel oil and steam while taking into service can cause thermal shock and undue stress and hence, cracking of tips.


Retraction of oil guns from normal firing positions can be eliminated by cooling critical parts of the atomizer continuously when the gun is not in operation. Air cooling of the non-operating oil guns tips in the firing position has been found to be adequate thus doing await the retract mechanisms

In this system, when the oil guns are out of operation they are not withdrawn but left in firing position itself. To protect the gun tips from overheating small quality of air at low pressure is supplied around the gun tip. Fins are provided to improve the cooling efficiency.

Basically, air-cooled oil guns consist of a finned cap nut and an air sleeve around it. The fins of the cap nut increase the heat transfer areas thus protecting the cap nut and simultaneously provide a very uniform distribution of cooling air to the oil gun tip efficiently.

The gun tip receives radiated heat from the flame and conducts it to the finned cap nut through the oil gun body. The air passing through the fins cools the finned cap nut and is directed into the gun tip at the exit.

To guide the cooling airflow through the finned cap nut and to ensure sufficient cooling airflow close to the gun tip, a directed air sleeve is mounted over the finned cap nut.


To facilitate easy insertion and removal of air-cooled oil gun assembly with air sleeve, an oil gun guide pipe of larger diameter pipe is used. A highly reliable cooling air system with cooling air taken from FD fan delivery is provided to ensure minimum cooling airflow through air-cooled oil guns under any adverse operating conditions.


  • Air-cooled oil gun tips are subjected to lower temperatures than retractable oil gun tips.
  • Minimizes the congestion at burner elevation,
  • Reduces the maintenance
  • Eliminates the number of working components / Complicated Retract mechanism
  • More economical than steam or compressed air cooling as the power requirements for low-pressure cooling air is minimal.
  • Increase in the life of the tip.
  • Can be retrofitted with old boilers easily without any major modification.
  • Oil guns remain in their firing position at all times – ready for immediate service
  • Oil guns remain cool and component life is increased
  • Eliminates “gun advanced’ and “gun retracted” limit switches
  • Simplifies control system
  • Increases accessibility to the burner front area

At present CCE &CE is offering this product as a retrofit to the automatically retractable type oil guns for application in utility boiler and the performance is proved in a lot of boiler installations.