Beverage preparation machines have been known for a number of years. For example, U.S. Pat. No. 5,943,472 discloses a water circulation system between a water reservoir and a hot water or vapour distribution chamber of an espresso machine. The circulation system includes a valve, metallic heating tube and pump that are connected together and to the reservoir.
A beverage preparation machine typically includes a housing containing a beverage processing module and a water tank in fluid communication with the beverage processing module. Examples of such beverage preparation machines are disclosed in EP 1 208 782, EP 1 267 687, EP 1 686 879, EP 1 731 065, EP 1 829 469, EP 1 864 598, EP 1 865 815, EP 1 867 260, EP 1 878 368, EP 2 222 210, EP 2 222 211, EP 2 222 212, EP 2 227 121, EP 2 227 122, US 2008/0006159, U.S. Pat. No. 7,165,488, WO 2007/111884, WO 2009/074553, WO 2010/015427 and WO 2012/055767.
Usually the water tank is removable to be refilled by a user when empty. Some systems include a continuous water supply by connecting the beverage machine directly to the city water distribution network, as for instance disclosed in CN201076369. This publication discloses a system that has a refillable water tank as well as an inlet for direct connection with the tap. Hence, beverage preparation can be carried out either by using water directly from the tap or from the water tank.