GB1316941A - Lighting apparatus - Google Patents

Abstract

1316941 Cooling high power lamps A H WRIGHT 27 May 1970 [27 March 1969 8 May 1969] 16060/69 and 23481/69 Heading F4R [Also in Division G2] A high power lighting apparatus comprises a lamp housing with a light exit aperture in one wall wherein this aperture is closed by a hollow light transmitting heat exchanger through which a coolant fluid passes. The embodiment described is a photographic enlarger in which four halogen lamps 33 are mounted in a stainless steel reflector 13 in a housing 3, the light being projected down through lens 10. Filtered, desiccated air is blown in through an air inlet pipe 42 to a space formed between a heat resistant glass plate 39 and a light-diffusing glass plate 40 between the lamp and the lens, and passes thence through the louvres 29 and via lamps and wiring to air outlet aperture 11 and louvres 15. Further, cooling water is pumped in through pipe 26 to close loop cylinder 24, running around the base of the housing, and passes through holes 25 into the space between the housing and the reflector which serves as a water jacket, and finally leaves the housing via pipe 17. In an alternative embodiment the air inlet pipe leads directly to an annular chamber connected to the space between the glass plates, and thence via the lamps and air inlet aperture 11 to an outlet pipe, Fig. 2, not shown. In a further embodiment, the space between the glass plates may be divided up by partitions so that the air is forced to follow a zig-zag path as it passes between them. Further the water passing through the water jacket may be forced to follow a helical path, either by the provision of spiral compartments or a helical pipe. Such cooling systems may also be employed in operating theatre lamps and studio spotlights.