Patent GB-191509544-A (GB)
Title: Improvements in or relating to Smoke Indicators for Furnaces.
Inventor: HEWITT JOHN BENJAMIN
IPC: F23M11/04
Filed: 1915-06-30
Abstract: 9544. Hewitt, J. B. June 30. Turbidometers.-A smoke-observation device for use in connexion with steam-generators comprises a source of light so arranged in the generator casing that a beam of light is projected across the path traversed by the furnace gases on to a translucent screen, also arranged at some point in the casing. In the arrangement shown in Fig. 1, a beam of light from the lamp D is projected through a lens in the tube C, across the path traversed by the furnace gases, on to a screen at B. Instead of employing a lamp, the light may be obtained from the furnace, as shown in Fig. 3. In this arrangement, the light from the furnace passes through an opening A<4> in the furnace wall on to a mirror G, from which it is reflected on to a mirror G<1> and thence through a lens in the tube C on to the screen B in the opposite wall of the furnace. Fig. 4 shows a modification in which the lamp D and screen are arranged in the same wall of the furnace. The beam of light is projected across the path traversed by the furnace gases on to a concave mirror arranged in a casing J, from which it is reflected back on to a screen in the casing M. One method of mounting the lens and tube C is shown in Fig. 6. The lens E is secured to one end of the tube C by a cap C', and the other end of the tube is adjustably mounted in a sleeve C<2> provided with a square flange C<3> adapted to slide into a flanged socket F on the furnace wall A'. Holes C' allow the passage of air through the tube C for cooling purposes. The ground glass screen B may be mounted in a socket such as F attached to the casing. Fig. 8 shows a combined mounting for lamp and lens. The lamp D is adjustable with respect to the lens E, which is conveniently fixed to a sleeve C<2> by a spring ring E'. The tube C is split and provided with lugs C<7> carrying a clamping-screw. The lamp is supported in a cap C<10>, which is gripped by the split end of the tube C'. A sighting-hole is provided at C". In the form of lamp and lens holder shown in Fig. 9, a square socket with flanges C<12> is provided for holding screens, the nature and number of which may vary. The screen K may be of opaline glass, the screen K<1> may be of tinted or shaded glass, while the screen K<2> is formed by an opaque stencil plate cut with a curve or other pattern corresponding with the shape of the lamp filament. The arrangement is such that the light from the lamp D as viewed through the screens K, K', K<2> is of the same intensity as the light on the ground-glass screen B, so that the light from the lamp D, as viewed through the screens K, K<1>, K<2>, constitutes a standard for comparison with the light on the screen B. The screen B may be carried in a socket arranged at one end of a tube which is provided at the other end with an adjustable sleeve carrying a lens, as shown in Fig. 8. The concave mirror H, Fig. 5, arranged in the casing J, shown also in Fig. 4, is mounted on arms H' attached to a pin H<2> supported by a hemisphere H<3> in a socket J<2>. Four setscrews such as J<3> bearing on the arms H' set the mirror in such a position as to reflect the light on the screen B.