| 摘要 |
1,080,069. Burner control. ESSO RESEARCH & ENGINEERING CO. March 21, 1966 [April 12, 1965], No. 12368/66. Heading F4T. In an oil-fired multiple burner system control of combustion to allow low excess air levels comprises balancing each individual burner 2 to obtain equal flame temperatures and subsequently adjusting the air/fuel feed to the burners simultaneously so that each burner operates at the desired excess air level. Fuel and air is supplied to each burner via a control valve 4 from manifolds 5 and 6. A master control valve 7 regulates the fuel/air ratio to the manifolds 5 and 6. The temperature of each flame 14 is sensed by hollow alumina tubes 3 and signals are conducted through fibre optic conduits 15 to an intercomparing unit 10 which in the event of an unbalance in the flame temperatures electrically signals a feedback control 11 which balances the burner via valves 4. The overall excess air level is determined by a flue gas analyser 8 and this level is periodically compared with the desired level by a master feedback control 12. In the event of a difference in levels a signal is sent through conduit 17 to the master control valve 7 which adjusts the overall fuel/air ratio. A timer in control 12 also periodically actuates through a conduit 16 the control 11 allowing it to respond to any imbalance signal from intercomparing unit 10. The unit 10 may comprise a single optical detector, e.g. a cadmium selenide photoresistive cell, and means for comparing the resistance levels of the detector for each burner and for producing an imbalance signal. Alternatively an optical detector may be placed adjacent each tube 3 and the individual resistance measured and compared manually. Alternative temperature sensing devices may consist of thermocouples, ultra-violet analysers or microwave analysers. Individual valves in the fuel and air lines may replace the dual control valves 4 and 7. |
