GB215015A - Improvements in gas indicating devices - Google Patents

Abstract

215,015. NeUissen, W. April 28, 1923, [Convention date]. Diffusion apparatus for gases.-In apparatus for indicating the presence of foraign gases in air by means of a diffusion cell and having, as described in Specification 208,718, a chamber containing sufficient air to effect several rinsings of the apparatus, conduits are provided between the air-chamber and the interior of the cell and and between the interior of the cell and the vessel within which the cell is enclosed, so that the rinsing air flows first through the interior of the cell and then through the enclosing vessel. The conduits may be controlled by a single member, which may also conrol the connection between the diffusion cell and the pressure gauge, the arrangement being such that the pressure gauge is put into communication with the atmosphere to restore it to zero after an indication has been obtained, and is cut off from the remainder of the apparatus during rinsing. As shown in Fig. 1, the apparatus comprises a chamber 1, containing compressed air for rinsing, and a diffusion cell 4 enclosed within a vessel 3 into which is fitted a valve 6 rotatable by means of a handle 7. The valve 6, as shown in Fig. 3, has three ports 8 - - 10, the angle between the first and the third being 120‹ and that between the last two 90‹. These ports are adapted to register with channels 11 - - 13 in the neck of the vessel 3, these channels being so arranged that the angle between the first and the third is 120‹ and that between the second and the third 90‹. Channel 11 is connected by a conduit 14 to the pressure gauge 15, channel 12 by a conduit 17 with the chamber 1, and channel 13 by a conduit 18 with the vessel 3. In operation, the valve 6 is turned to the position shown in Fig. 3, in which position the cell communicates by way of,port 9, channel 11, and conduit 14 with the pressure gauge. The gas to be tested is introduced into the vessel 3 through a pipe 19, this pipe fitting loosely into the vessel so as to prevent any excessive increase of pressure therein. When an indication has been obtained, the valve is turned so that port 8 registers with channel 11, in which position the pressure gauge is brought into contact with the atmosphere by way of the cell, port 10, and channel 13. To rinse the appartus, the valve is turned so that port 9 registers with the channel 13 and port 10 with channel 12. Air from the vessel 1 then passes by way of conduit 17 and channel 12 into the cell and thence through port 9 and channel 13 into the vessel 3. A new indication can then be obtained by turning the valve 6 to its original position and introducing a further quantity of gas.