Express coffee dispenser with pressure regulation - uses water accumulator to regulate pressure in system and to provide cleaning water for internal passages

摘要

A solenoid under manual or automatic control displaces a valve (14) to allow hot water to pass. The displacement of the valve closes the outlet (14b) forcing hot water into passages (10,11) feeding an accumulating chamber (12) and a percolator chamber (13). The resistance of the coffee powder causes the water pressure to overcome the (adjustable) spring pressure in the accumulator chamber (12) displacing a piston (12b) so reducing the water pressure in the water circuit as the hot water penetrates the coffee powder. When the de-activation of the solenoid allows the valve to fall, the hot water entry (14a) is closed and the pressure in the percolator chamber forces the coffee through the outlet (15). A spigot (17) of variable section retards the flow of water from the accumulator, causing the water to discharge slowly and wash the passages (10,11) and the valve.