The apparatus here illustrated is recommended by a German manufacturer for the employment of liquid carbonic acid in the preparation of carbonated beverages. The apparatus itself is different in some respects from the American apparatus, as can be readily seen. It consists of an expansion vessel and a mixing cylinder. The former, which is connected with the receiver by a lead pipe, is provided above with a manometer as well as a safety valve. A second tube connects it with the mixing cylinder - the large cylindrical vessels represented as lying upon its side - which is also fitted with a manometer and safety valve, and has, besides, an opening for introducing the liquid to be charged with the gas, and a stirring arrangement to mix the contents. A pipe of block-tin, somewhat larger than the others, leads to the filling and corking apparatus, by means of which the carbonated liquid is drawn off into bottles. The mixing cylinder is also provided with a pet-cock for permitting the escape of atmospheric air, which is expelled from the water when it is first charged with the gas. The liquid carbonic acid is contained in the strong iron cylinder shown alongside of the table in an oblique condition. The reservoir, which is of wrought iron and capable of standing a great pressure, has, at one end, an inlet guarded in the interior by a valve which permits opening only inwards. After a little of the gas has been pumped in, a stop-cock at the other end is opened to let out the air. This is done several times, in order to make sure that all the air has been expelled. Then the gas is pumped in continuously, until the manometer indicates a certain pressure. During the process of filling, the cylinder is surrounded with ice.

Fig. 212.   Automatic Pressure Governor Attached to Liquid Carbonic Acid Cylinder

Fig. 212. - Automatic Pressure Governor Attached to Liquid Carbonic Acid Cylinder.

A, Patent automatic pressure governor and gauge; B, Main valve; C, Cylinder containing the gas; D, Coupling for connecting outlet of cylinder to governor; E, Wing screw for setting the gauge to the pressure-point required; F, Cocks; G, Hand wheel of main lever.

Fig. 213.   German Carbonating Machine with Liquid Carbonic Acid Cylinder

Fig. 213. - German Carbonating Machine with Liquid Carbonic Acid Cylinder.

This expansion cylinder, however, is no necessity. Where two or more carbonic acid cylinders are attached to an apparatus or at hand the charging of a fountain can be done rapidly and directly to any pressure desired, which cannot be done from the expansion cylinder without the aid of a pump. Thus the expansion cylinder is only an accumulation of apparatus. Where a gasometer belongs to the set of machinery in use, it might be charged from a carbonic acid cylinder instead of from the generator, thus representing, or acting for, an expansion cylinder.