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ers which receive carbide-containing trays divided by partitions into a number of compartments which are half filled with carbide. Water is supplied from the gasholder tank through the tap E and pipe F to the generating chambers in turn. It rises in the latter and floods the first compartment containing carbide before gaining access to the second, and so on throughout the series of compartments. As soon as the carbide in the first generating chamber is exhausted, the water overflows from it through the pipe with by-pass tap J to the second generating chamber. The taps G and H serve to disconnect one of the generating chambers from the water-supply during recharging or while another chamber is in action. The gas evolved passes from each generating chamber through a pipe L, terminating in the dip-pipe M, which is provided with a baffle-plate having very small perforations by which the stream of gas is broken up, thereby subjecting it to thorough washing by the upper layers of water in the gasholder tank. The washed gas, which thus enters the gasholder, passes from it through the pipe N with main cock R to the service- pipes. The water-supply to the generator is controlled through the tap E, which is operated by a chain connected to an arm attached to the bell of the gasholder.
The water in the gasholder tank is accordingly made to serve for the supply of the generating chambers, for the washing of the gas, and as a jacket to the generating chambers. The heat evolved by the decomposition of the carbide in the latter creates a circulation of the water, ensuring thereby thorough mixing of the fresh water, which is added from time to time to replace that removed for the decomposition of the carbide, with the water already in the tank. Thus the impurities acquired by the water from the washing of the gas do not accumulate in it to such an extent as to render it necessary to run off the whole of the water and refill, except a