This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
"Where it is desirous to have a more showy, and at the same time independent and complete gasometer, the sides can be mounted with three upright supports, weights, lines, etc. The two pipes shown by the dotted lines in drawing are fixed by suitable strong gun-metal connections to the side of the tub. These are made of thick hard-drawn copper tube, tinned inside and out, and will last many years without decay. When required we substitute solid tin pipe. The pipe from the generator has its upper end bent, and is called the 'gas inlet pipe,' the purpose being that the carbonic acid gas as it rushes through forces itself down some distance under water - the height of the water being shown by dotted lines across the tub - then rises to the surface, and the slight excess of pressure causes the bell to rise. It is almost impossible for the gas when it has once passed by this pipe to return, as the orifice is covered with the water, and thus the gasometer once charged remains quiescent until the other pipe is brought into operation. This pipe is straight at its upper end, and rises above the water-line about five inches, and is called the 'gas outlet pipe,' and is connected with the pump by means of a tin pipe, which must be bent to the form shown.
"The water in the gasometer should be changed about once a month when in full use, but this depends upon whether the purifier be used, as the impurities which are caught by the purifier prevent the water becoming so soon impure as it otherwise would do.
"The process of making carbonic acid gas is extremely simple. Sufficient whiting or other carbonate is put into the generator through the cap, then water is added, the whole being mixed - so as to dissolve the carbonate - by means of the handle of the mixer, then the cap is screwed on again. Sulphuric acid is now poured into the funnel, and the handle of mixer slowly turned. An effervescence now takes place in the generator; this effervescence throws off carbonic acid gas, which is forced by its own pressure into the gasometer. When the bell is nearly as high as it should go, then the mixing process in generator must be stopped; no accident can possibly occur, as no pressure is confined.
"The machine is the next in rotation that we have to describe, and it is of the utmost importance that necessary detail should be fully carried out in this. We will now follow the pipe from gasometer. This is a solid tin pipe, bent as shown in drawing to prevent the possibility of water passing into the gas outlet pipe. At the end of the tin pipe is a gun-metal connection, screwed to a cock fitted with an index plate with raised figures, the handle of the cock having a pointer to mark the position, and is directly in communication with the pump; on the reverse side of pump is a similar cock, with a stoneware or copper solution pan which supplies the water to be carbonated.
"The pump is made of the very best close-grained gun-metal, and has a suitable valve-box connected to the top of it. , In this is fitted two valves of special make, with prepared leather tips to them; one is a draught, the other a stop valve. The inside of this pump, valve-box, and valves are all thickly tinned. The valves are easily lifted out of their places when required.
"The plunger works up and down from the underside of the pump, and is kept tight by a suitable cup leather. When the plunger is lowered it draws gas and water at the same time - the proportion of each being regulated by the index cocks - and when raised it forces the gas up an S pipe into the condenser. The plunger is a solid ram; avoid bucket plungers.
"The condenser, which is made of well-planished copper - or gun-metal, if preferred - is of an oblong shape, thickly coated internally with pure tin, and fitted together in two halves by gun-metal flanges, with steel bolts and nuts. It is thus easily disconnected for repairing, re-tinning, or re-silvering; between the flanges is patent inodorous packing, so that the water is not flavored with either leather or rubber. At the top of the condenser is a connection to which is attached a dial pressure-gauge, for denoting the pressure inside; at the back part is fixed a suitable stuffing-box, for receiving the rod of agitator, which is kept tight by a single cup leather.
"The agitator is a flat disc of tinned copper with holes through it, its purpose being to mix the gas and water together as they are forced into the condenser by means of the pump. This is one very vulnerable point in defective machinery, where metallic friction is liable to occur, but in our machines all friction is entirely exterior, the agitator having suitable supports outside. It is driven by a toothed pinion wheel, in connection with a larger one on the crank shaft.
"The bottling cock is fixed to the front of the condenser; it has a strong gun-metal square-threaded screw with a rounded point, and is closed by means of the handle on to a conical seating. The under part has a leather or rubber cone-piece, which is inserted partly into the mouth of the bottle when required for knee-bottling only, but when either of the filling machines is required it is upon this cock that the pipe for the same is fixed.
"The safety-valve is fixed on top. as shown, and is used for blowing out the atmospheric air from the condenser when first charging; it afterwards acts as a safety-valve in case the condenser should be over-charged with pressure. We have lately effected an improvement in this valve to prevent the escape blowing over the outside of condenser; it now blows down a pipe at the side, either into the gasometer, or, by preference, into the solution pan.
"The distance that each - the generator, gasometer, and machine - is from one another does not matter, it is merely a question of lengthening the pipes between each to suit convenience".
The above cut represents a continuous apparatus of the same system with upright cylinder.