GB1386657A - Pilot gas burner assemblies - Google Patents

Abstract

1386657 Pilot burners COLT INTERNATIONAL Ltd 26 March 1973 [29 March 1972] 14642/72 Headings F4F and F4T A pilot gas burner assembly comprises a tubular body 24 with a throat 25, between its ends, one or more primary air holes 32 admitting air into body 24 with a swirling motion and on one side of the throat, means 17, 30 for admitting fuel gas into body 24 on said one side of throat 25, ignition means 20 for igniting the fuel/air mixture at throat 25, secondary air holes 34 for admitting air on the other side of throat 25 with a swirling motion in the same direction as that of the primary air, and one or more tertiary air holes 36 for admitting air into body adjacent an open outlet end of body 24 and with a swirling motion in the same or the opposite direction to that of the primary and secondary air. The tertiary air flow produces a region of turbulent air near the outlet of body 24 to stabilize the flame position relative to a flame-sensing rod 23. Each of the holes 32, 34, 36 is formed in one flat side wall of the body 24 which is of uniformally square internal and external crosssection, although the outlet may be circular, the axis of the hole being disposed normal to that wall portion to direct air along the inside of an adjacent flat wall portion. The pilot burner is ignited by a spark between an electrode 20 and a throat-forming insert and is used to ignite gas from ports 12 of a main burner 11, Fig. 1, having a flame spreader 13 and baffle 14. The pilot and main burners are located in a burner chamber 40 into which air is admitted with swirl through vaned inlets 41 from a surrounding volute chamber (not shown). This air swirls upwardly to outlet 23 with increasing velocity but the total pressure in this airstream is substantially constant, whereby the upper end of body 24 is in a region of lower static pressure than its lower end and air is accordingly induced to flow into body 24 through holes 32, 34, 36.