450
ugh a mechanism consisting of a double oscillating cup so weighted that normally the feed is closed. The fall of the bell of the equalising gasholder, into which the gas evolved passes, operates a lever B, which rotates the weighted cup in the neck of the hopper and so causes a portion of carbide to fall into the water in the generating tank. The feed-cup consists of an upper cup into which the carbide is first delivered. It is then tipped from the upper cup into the lower cup while, at the same time, further delivery from the hopper is prevented. Thus only the portion of carbide which has been delivered into the lower cup is emptied at one discharge into the generator. There is a safety lock to the hopper cap which prevents the feeding mechanism coming into operation until the hopper cap is screwed down tightly. Provision is made for a limited hand-feed of carbide to start the apparatus. The gasholder is fitted with a telescoping vent-pipe, by which gas escapes to the open in the event of the bell being raised above a certain height. There is also an automatic cut-off of the carbide feed, which comes into operation it the gas is withdrawn too rapidly whether through leakage in the pipes or generating plant, or through the consumption being increased above the normal generating capacity of the apparatus. The gas evolved passes into a condensing or washing chamber placed beneath the gasholder tank and thence it travels to the gasholder. From the gasholder it goes through a purifier containing "chemically treated coke and cotton" to the supply-pipe.
[Illustration: FIG. 27.--"OMEGA" GENERATOR.]
1 Vent-cock handle. 2 Residuum-cock handle. 3 Agitator handle. 4 Filling funnel. 5 Water overflow. 6 Hopper cap and lever. 7 Starting feed. 8 Rocker arm. 9 Feed connecting-rod. A Pawl. B Lever for working feed mechanism. C Guide frame. D Residuum draw-off cock. G Chain from hopper cap to feed mechanism. H Blow-off and vent-pipe connexion. I Gas outlet from generator. J Gas service-cock. K Filling funnel