GB250478A - Improvements in electric flue gas testing apparatus - Google Patents

Abstract

250,478. Wichnevsky, G. Sokolow-. Oct. 12, 1925. Resistances, measuring -An electric gas-testing ap paratus for determining carbon monoxide or dioxide in flue gases by measuring the variations in the resist ance of a conductor located in the gases under test comprises a tubular cooler X, through which the gases are passed, a waterjet pump B placed below the cooler and a filter F and cell A containing gas and air chambers placed at the upper part of the cooler. The gases enter the appar atus at 1, pass through the pipe 2 inside the cooler and through the filter F which consists of a filter cloth 17 and a vessel filled with filtering materials, enclosed in a bell-shaped cover 15 with an oil seal 16. The flue gases are drawn through the filter and along a pipe 6 by the pump B, which is worked by the water supplied to the cooler through the pipe 3. Part of the gases pass through a chamber 18 in which are located wires 23 arranged in opposite arms of a wheatstone bridge, as shown in Fig. 2. Similar wires 24, forming the remaining arms of the bridge, are located in an air chamber 19. In order to compensate for the steam content of the flue gases, which will depend on the temperature of the cooling water, conductors 31, 32 of different temperature coefficients are placed in the cooling water and connected up in adjacent arms of the bridge. When carbon dioxide is to be determined, the wires 23, 24 are heated to about 100‹ C., and the variations in the resistance of the wires 23, due to the lower specific heat-conductivity of carbon dioxide, are measured. If the monoxide is to be determined, the wires are made of platinum and heated to about 400‹ C., the temperature of the wires 23 being increased by the combustion of the carbon monoxide. The measuring instrument 30, which may be a dynamometer when an alternating current source is connected to the bridge, may be graduated to. read in percentages of the dioxide or monoxide.