Expresso coffee machine

Claim 1

An expresso coffee machine comprising: A. a boiler including, 1. heating means therein; B. a water supply conduit, from a source of supply, opening into said boiler, including, 1. automatic control means to maintain a predetermined water level in said boiler; c. an immersion tube in said boiler, normally filled with hot water, connecting at its first end with said supply conduit by a second conduit; D. a coffee brewing receptacle, fixed relative to the front of the machine, normally provided with a predetermined amount of ground coffee, a third conduit connecting between a second end of said immersion tube and brewing receptacle; E. a water doser comprising, 1. a cylinder in open communication with said second conduit, 2. a plurality of electrodes extending into said cylinder to varying depths of penetration including, a. a long, ground electrode having the greatest depth of penetration, b. a short electrode having the least depth of pEnetration to determine the maximum amount of water received therein from said second conduit, c. at least two electrodes having variable, intermediate depths of penetration; F. a selector switch providing multiple positions for electric connections to the respective intermediate electrodes; G. an electric switch means for completing an electric circuit, as determined by the position of said selector switch, to energize an electric water pump to deliver a predetermined volume of water from said cylinder, through said second conduit to said first end of said immersion tube whereby a like volume of hot water is displaced through said third conduit to said coffee brewing receptacle, said volume of water being determined by the depth of penetration of the electrode through which the circuit is completed; H. electric valve means to automatically return the volume of water in said cylinder to its maximum depth.