GB785019A - Improvements in or relating to smoke observation apparatus - Google Patents

Abstract

785,019. Observing smoke. BARR & STROUD, Ltd. Jan. 28, 1954 [Feb. 19, 1953; Dec. 21, 1953], Nos. 4636/53 and 35436/53. Class 51 (1). [Also in Group XX] A smoke observation apparatus comprises a light source directing a beam across a smoke conduit, and means for intercepting the beam after passage through the smoke to focus an image of the smoke on a light dispersive screen so that the image may be viewed over a wide angle. A lamp unit 7 projects a beam of light across the uptake 6 of an oil-fired boiler on to a mirror unit 9 which reflects the beam down an upright tube 10 to a mirror unit 11 which reflects the beam on to an upright viewing screen 12 of frosted glass or plastic material. The lamp unit 7 comprises a cylindrical part 14a perpendicular to the uptake 6 and welded into a hole in the uptake wall, a second part 14b connected to the part 14a by a bayonet connection and carrying a condenser lens 23 of heatresistant glass sealed to its inner end so as to close the uptake 6. A third part 14c bolted to the outer end of the part 14b carries a lamp socket. A one-way inlet 25 in the part 14a enables compressed air to be blown across the uptake side of the lens 23 to clean it. A part 26 is welded into the uptake 6 opposite the part 14a and the mirror unit 9 screws over its outer end. A window 42 of heat-resistant glass is hingedly mounted at the inner end of the mirror unit 9 and clamped against the outer end of the part 26 which has an inlet 45 to allow the window 42 to be cleaned by compressed air. A mirror 31 is carried by an adjustable three-point suspension on a cover plate 34 which is hinged and clamped to the mirror unit 9. The mirror 31 is at an angle of 45 degrees to the window 42 and a projector lens 13 clamped to the lower end of the unit 9. The vertical part 10 is screwed to the lower end of the unit 9 and the base mirror unit 11 is screwed to the lower end of the tube 10. A mirror 47 is mounted in the unit 11 in a similar manner and parallel to the mirror 31 mounted in the unit 9. A screen 12 is supported vertically in an extension of the unit 11. An auxiliary light source may be arranged to form a spot of light on the screen, and the illumination intensity of the light spot may be varied by a rheostat controlling the source or an adjustable filter between the source and the screen so that the density of the smoke may be estimated. Alternatively a ring of light filters of different densities may be provided on the screen so that by observing the lowest density filters which remains completely dark, the density of the smoke may be estimated. In a further modification a jet of compressed air injected into the part 26 causes turbulence in the smoke in the flue at the end of the part 26 and makes it more easily visible on the screen.