GB842006A - Hydraulic coffee machine - Google Patents

Abstract

842,006. Coffee making machines. WURTTEMBERGISCHE METALLWARENFABRIK. Aug. 8, 1956 (Aug. 16, 1955]; No. 24331/56. Addition to 823,546. Class 129. [Also in Group XXIX] In a coffee beverage making machine, connected working and supplementary pistons 6, 10 are displaceable in two cylinders 1, 2, the working piston 6 being displaceable by a pressure medium fed to working chamber 7 to discharge hot water from cylinder 1 through ground coffee or the like, the cylinder 2 having a return pressure chamber with an opening in its cylindrical wall through which the pressure medium acts after the piston has passed beyond it to prevent further movement thereof by closing a valve 4 connected between chamber 7 and a manuar control valve 3 so arranged that, when chamber 12 is connected to the pressure medium, chamber 7 is connected to a discharge pipe and vice versa. The pressure medium may be hot water under pressure. Pistons 6 and 10 are connected by a hollow piston rod with a passage 13 there through which connects chambers 7 and 11. A filter holder 19 is fixed underneath the brewing chamber 8 of cylinder 1, e.g. by a bayonet fitting. Chamber 8 is connected to a hot water boiler through a spring biassed valve 22 held closed by piston 6 when in its lowest position and allowed to open to admit hot water to chamber 8 when piston 6 is raised. Openings 28, 29, 30 in the wall of cylinder 2 are connected by pipes 31, 32, 33 to a manually operated cock 5 which connects the selected opening to a pipe 34 so that pressure fluid from chamber 12 can close valve 4 and stop discharge from chambers 7 and 11. When piston 10, and hence piston 6, has reached the desired height according to the amount of coffee to be made. The control valve 3 comprises an ante chamber 47, connected via valve 40 to chamber 7, an antechamber 38, connected to chamber 12, a chamber 50, connected to a supply of hot water under pressure,.a bore 52, connected to a discharge pipe 53 and two double valves 54 and 59, 60. These valves are simultaneously manually, operated to connect either chamber 7 to the supply of hot water under pressure and chamber 12 to the discharge pipe or chamber 7 to the discharge pipe and chamber 12 to the hot water under pressure. The machine is normally in the position shown in Fig. 1 and to initiate operation valve 3 is operated in direction B to the position' shown in Fig. 2, where hot water under pressure is fed to chamber 12, piston 6 is raised to the extent, determined by the setting of cock 5, to draw in the required amount of hot water into chamber 8. Valve 3 is then operated in direction A so that pressure fluid is fed to chamber 7 and hence chamber 11 and piston 6 forces the hot water out through the coffee grounds in the filter. Reference has been directed by the Comptroller to Specification 788,980.