New experiments upon the combustion of well-dried carbon monoxide and oxygen mixtures.—Part II

Abstract

For this third series of experiments a special form of apparatus (shown diagrammatically “in plan” in fig. 1) was set up, whereby the ignitibilities of 2CO + O 2 mixtures, whose components had been thoroughly dried (after compression) over re-distilled phosphoric anhydride in small steel cylinders, could be tested in a nickel-steel bomb with a 1-in. diameter cylindrical explosion chamber at various initial pressures up to 20 atmospheres. The whole system and its connections had been previously thoroughly dried out by continuously circulating P 2 O 5 -dried nitrogen round it day and night for several months together. The following is a detailed description of the apparatus :— Apparatus . The nickel-steel cylindrical bomb A* (with explosion chamber 8 inches long by 1 inch diameter, capacity 103 c. c.) was clamped horizontally to a special iron casting, which permitted of the bomb being rocked as and when required. This was bolted down to the experimental table, on to which were also fixed all the other items of the installation. The outside of the bomb, whose overall dimensions were 16 inches by 5 inches diameter, was wound with nichrome wire, so that it could be heated electrically to a temperature of 150° C. or more to facilitate the drying of it. It was fitted with a specially designed firing plug P, consisting of a central electrode (5 inches long by 1/8 inch diameter nickel-steel rod), which was wrapped round with an insulating packing of compressed mica to a thickness of 5/16 inch, in such a manner as to make a perfectly gastight joint even at high explosion pressures. It should be particularly noted that no organic substance whatever was employed in “packing” the firing piece, or indeed in any other part of the bomb or apparatus. The electrode of the firing piece projected about 3½ inches out of the body of the bomb in order to allow of a sufficiently high voltage being applied when a mixture had to be fired under high pressure. The bomb was closed at each end by the high-pressure steel valves V 1 and V 2 , respectively.