US Patent 7434587 Water guide for dishwasher

A water guide of a dishwasher checks the flow of water draining from the dishwasher. The water guide includes a drain passage having one end communicating with an outer atmosphere and another end communicating with a sump for receiving washing water, at least part of the drain passage being routed via a point higher than a water level in the sump, and a valve assembly, disposed above the drain passage, for selectively introducing external air into the drain passage.