This is illustrated by the next engraving.

"The liquid to be carbonated enters through inlet pipe A. A float valve in B regulates the supply. The water runs through connecting pipes to the top of the chambers C C, where it separates into spray in falling through the one or more sieves, as may be adjusted. While thus separated the liquid is subjected to a continuous vacuum suction through pipes connecting the tops of the chambers C C with air-suction pump D, which maintains the vacuum and purges out the air and discharges it. The liquid then collects in the reservoir formed by casing B around the valve head, and is sucked together with carbonic acid gas, which enters through inlet pipe E, through a regulating 3-way valve key F into the , barrel of the compressing pump H G. From here both are discharged through the first of pipes I and sprayed against the top of chamber J, from whence the liquid is forced back to and through the spray sieve below, and thus is repeatedly broken up into the smallest possible particles and impregnated with the gas. After collecting again at the bottom of the first chamber, the pressure of the next discharge of the pump will force the liquid and gas again to the top of the second chamber, where they undergo the same spraying or atomizing and impregnation. These chambers can be multiplied, but experience has shown two to be sufficient under conditions offered by the other parts of this apparatus. To prevent the vacuum from the feed chambers C C from drawing the gas into them, an automatic stop valve is provided, which prevents the gas from entering the chambers C C. All water ways are either block-tin lined or electro-plated with silver.

"The liquid now thoroughly combined with the gas passes through a connecting rubber pipe into the main reservoir M. Here it collects and forms a steady supply to the discharge P, leading either to portable fountains or to the bottling table. A water glass is provided although not absolutely necessary, as the pump is automatically regulated by the main reservoir; the latter is placed on a perpendicularly guided stand, which is counterbalanced on pivot N. As soon as it becomes overfull it will sink, and the lever of the counterweight rise; the latter being connected at 0 with the regulating valve lever F. This will shut off the liquid inlet from chamber B, but not that of gas E, so that the pump will be supplied only with gas, forcing it through chamber J and main reservoir M, where it will work through the liquid contained therein. A safety and blow-back valve combined allows any over-pressure of gas to escape back into the gas-holder from whence it is again used. No gas is thus wasted. The apparatus consequently is self-regulating as well as economical, the pump piston, consisting of two stiff leather cups flaring in opposite directions and forming a recess in which water collects, serving as lubricator. These cups form a large packing surface, are tightened by strong set screws, and will not leak even under high pressure. The same pump barrel and piston, with a separate valve head at the bottom, form the air pump, thus greatly simplifying the apparatus. A water jacket around the pump barrel prevents heating. On the air-suction pipe a regulating valve is located for the purpose of enabling the pumps to suck sufficient air from the outside to prevent over straining and to maintain an even vacuum".

Witteman s Patent Pneumatic Carbonator 135