15. Description
The Mixer consists of two meters arranged side by side. They are operated by the pressure of the Gas and Air passing through them.
The gas pipe from generator connects with inlet of gas meter, so that all the gas must pass through the Mixer. A branch air pipe is connected with inlet of air meter. The meters deliver their gas and air into a common mixing chamber at top of MIXER, whence the mixed (or qualified) gas passes through the pipes to the burners.
The shafts of meters are provided with cone pulleys (grooved as shown in cut) which are connected together by a rubber belt. The relative movement of the meters is determined by the position of the rubber belt on the cone pulleys, and the proportion of Gas and Air passing into the mixing chamber is exactly according to such relative movement of the meters.
When fresh Gasolene is put into the generator, the belt is placed in grooves nearest the Mixer, which makes the movement of the air meter much faster than that of the gas meter, and secures a mixture of about 10 parts gas to 90 parts air. As the Gasolene is reduced the belt is shifted from time to time, until on the grooves farthest from the MlXER, when the mixture is about 90 parts gas to 10 parts air.
The shifting of belt is all the attention required. It is the work of a moment, and has to be done but three or four times a month.
The Dunning Boiler. For warming all classes of buildings by steam or hot water systems. 
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