A new secondary burner has been successfully designed and tested for DQ1000inert gas extinguishing set which is to put out an underground fire

especiallya fire in coal mine tunnel. Its main design features are low gas flow velocity

two-zoned fuel supply

bypass torch ignition

multirow flame holders

injection of water into combustion zone

and water cooling system in both outer casing and exhaust section etc. The test results demonstrate Its good performances

such as flexible ignition capacity

stable combustion

high combustion efficiency up to 99%

safety and reliability. Particularly

oxygen content in volume is lower than 3 % in exhaust gases. The set was certificated in 1985 and passed the test in underground fire zone. The practice has proved that extinguishinga big fire by means of inert gas is an effective method at present.