Today in 1934, US Patent 1969643 A was issued, an invention of Gottfried Fuchs and Hermann Spath, for their “Beer Cooling and Dispensing Apparatus.” There’s no Abstract, although in the description it includes these claims:

This invention relates toan automatic cooling and pressure plant for beer conduits and cold storage rooms with employment of frozen carbon dioxide.

It is already known, to employ frozen carbon dioxide for cooling chill rooms. These plants, however, are open to the objection that the carbon dioxide becomes lost as soon as it is no longer frozen. This circumstance renders very l0 questionable the economy of this cooling method, because, as is known, carbon dioxide is very expensive.

The invention relates to a plant, in which the gaseous carbon dioxide liberated by evaporation cools the chill room and also the beer conduit in the tapping device and at the same time serves as pressure medium for the beer in the barrel. ‘The dry ice is accommodated in the cold storage room in a. receptacle with insulated walls, from which go vessel the gaseous carbon dioxide liberated by evaporation is conducted into the beer conduit cylinder through a cooling pipe conduit extending through the cold storage room. The beer conduit cylinder is surrounded by a jacket accommodating the cooling water. The gaseous carbon dioxide is conducted-as pressure medium from the beer conduit cylinder in to the barrel. Posterior the receptacle accommodating the dry ice and anterior the cooling pipe conduit a known thermostat is arranged, by means of which the passage from the ice receptacle to the cooling pipe conduit is automatically regulated.

The jacket of the beer conduit is surrounded by a further jacket, the internal space of which is filled with cooling water which, owing to the expansion of the carbon dioxide in the cylinder, is cooled to freezing point, so that an ice jacket is formed around the beer conduit. The ice jacket is surrounded by a further jacket the internal space of which is filled with cooling water in order to protect the ice jacket against the external heat.

By means of this plant the dry ice is employed for three purposes, i.e. to cool the cold storage room and the beer conduit and to place under pressure the beer conduit, so that the dry ice is utilized in the most economical manner.