GB775680A - Improvements in or relating to indicating means - Google Patents

Abstract

775,680. Indicating-apparatus. KELVIN & HUGHES, Ltd. Sept. 2, 1955 [June 18, 1964], No. 17959/54. Class 106 (4). Indicating-apparatus comprises vanes 29, 33 made of light-transmissible material of different colours, means for moving the vanes independently of each other in accordance with different variables and illuminating means 22 for throwing overlapping shadows of the vanes on a screen. Apparatus for assisting in the maintenance of the correct fuel to air ratio in a boiler furnace comprises a scale plate 12 with four windows 16, 17, 18 and 20 each with a translucent cover forming a screen and scale markings for temperature and carbon dioxide content alongside windows 16 and 18 respectively. A lamp 22 and lens assembly 23 produce a beam to illuminate all the windows and vanes 28, 29 and 32, 33 connected by arms 27, 31 to the moving coils of millivoltmeters 25, 26, connected respectively to a thermocouple in the chimney and an electric gas analyser, interrupt the beam to throw shadows on the screens behind windows 16, 17, 18. Opaque parts 28, 32 of the vanes throw dark shadows behind windows 16, 18 and light-transmissible parts 29 coloured red and 33 coloured green where they overlap throw a dark shadow on the screen behind window 17. and clear coloured sectors where they do not overlap, thus the undesirable condition of high temperature and low carbon dioxide content is indicated by an upper red sector, while an upper green sector indicates that conditions are better than the calculated normal, the length of the coloured sector giving a measure of the divergence from normal. Waste of fuel may be indicated by an amber vane 40 moving with the coil of a millivoltmeter 42 operated by a gas analyser.