device for electro chemical determination of carbon monoxide

摘要

1,000,625. Gas analysis. BECKMAN INSTRUMENTS Inc., Feb. 7, 1964 [Feb. 13,1963], No. 5195/64. Headings G1B and G1N. In an apparatus for the determination of the amount of carbon monoxide in a gas sample stream. Iodine vapour is produced in a converter 21 by the reaction of the carbon monoxide with iodine pentoxide and is delivered to a first electrode (cathode) 38 in an electrochemical cell having a halide solution as the electrolyte, and a second electrode (anode) 44 remote from the path of the iodine vapour, the electrodes effecting the reduction of the iodine vapour and the generation of a current that is indicative of the rate of entry of iodine vapour and thus proportional to the rate of supply of carbon monoxide in the sample gas stream. The converter comprises a cylindrical heater 34 around a central tube 32 containing granulated iodine pentoxide or a mixture of powdered iodine pentoxide with small glass spheres supported on a wad 35 of glass wool. The electrolyte is circulated around the conduit loop 11, 16,10 by bubble lift during which the iodine is dissolved in the electrolyte, the gas passing to atmosphere via a flowmeter 28 and aspirator 30. The electrolyte descends over the platinum cathode and the dissolved iodine is reduced. The electrochemical reactions are given. A conduit extension 12 from the bottom of the conduit loop is passed through a hole in a stopper 15 and communicates with an anode chamber 14 wherein a platinum wire 42 woven through a graphite cloth 44 is immersed in a sludge 46 of active carbon particles to form the anode. A small platinum screen 45 is provided in the vicinity of the point of emergence of the wire from the carbon in order to facilitate the escape of hydrogen during recharging. In a modification, Fig. 2, the cell comprises two separate compartments 52, 76 connected by a plastic sleeve 78 and the sample gas is injected into an inner or cathode compartment 54 of porous glass, porous ceramic or other porous material lined with a platinum cathode screen 56, the compartment 54 dipping into the electrolyte 94 which may be the same as in Fig. 1.