Patent ID: 8028710

Claim:
A hand-washing system powered by water, comprising: a work enclosure that includes: an upper end when said work enclosure is in use; a lower end when said work enclosure is in use, said lower end spaced from said upper end and defining an energy dissipation region for containing water having a first depth; a longitudinal central axis extending between said upper end and said lower end; a sidewall extending between said upper end and said lower end; a closure substantially closing said lower end; an interior space substantially defined by said sidewall and said closure; and a spray nozzle located at said upper end, said spray nozzle having an inlet, an inlet water pressure at said inlet during use, and a spray exit orifice configured to provide a spray of water at an outlet flow rate (Q) and a nozzle exit velocity (V) during use, said spray nozzle configured so that 1) the outlet flow rate is at least 0.7 gallons per minute when the inlet water pressure is 20 pounds per square inch and 2) said spray nozzle has a V/Q ratio of at least 20 gallons-per-minute per feet-per-second, wherein said spray exit orifice is oriented to direct the spray of water into said interior space; wherein said sidewall contains a digit portal receiving at least one digit of a hand of a human user during use, said digit portal in fluid communication with said energy dissipation region and spaced from said closure along said longitudinal central axis so that water present in said energy dissipation region in excess of said first depth may flow out of said interior space through said digit portal, further wherein said digit portal is positioned in said sidewall along said longitudinal central axis and said spray nozzle is configured so that said first depth of said water in said energy dissipation region is sufficient, when said at least one digit is not present in said interior space, to preclude said spray of water from said spray nozzle from parting water present in said reservoir of said energy dissipation region deeply enough to reach said closure when said inlet water pressure is less than 60 pounds per square inch.