Method and apparatus for washing dishes allowing independent control of washing liquid flow to upper and lower baskets. A valve allows selective reduction of liquid flow to an upper washing arm and/or by-passing liquid so that it does not flow through the washing arm nozzles.

An apparatus for cleaning an endoscope comprises an upper spray head which is disposed toward the central axis of a rinse vessel, and a lower spray head disposed toward the wall of the rinse vessel. A portion of an endoscope is disposed around the central axis of the rinse vessel, and the spray heads direct a cleaning liquid toward the endoscope portion from above and below in an oblique direction while rotating about the central axis. The spray heads do not have to be removed to place or remove an endoscope portion to be cleaned.

A method of washing objects in a dishwasher having upper and lower spray arms within a wash chamber and a sump filter. Wash liquid entering a sump from the wash chamber to be recirculated by a pump is filtered the filter to prevent soils from entering the sump and being recirculated. When the lower spray arm is operating, wash liquid is directly sprayed onto the filter from a clean-out nozzle on the lower spray arm to clean soils off the filter and prevent the filter from clogging. During a pre-wash cycle and at least one pre-rinse cycle, wash liquid is continuously sprayed from only the lower spray arm to prevent the filter from clogging when heavy soils are removed. During a wash cycle and at least one rinse cycle, wash liquid is alternately sprayed from the lower spray arm and the upper spray arm when the heavy soils have already been removed and it is less likely the filter will become clogged.

An improved nozzle assembly for a dishwasher is provided. The nozzle assembly includes first and second nozzles rotatably installed adjacent to corresponding first and second racks so as to selectively spray water in first and second directions. One of the nozzles includes a device for manually setting the spraying direction, including a fixed central piece and first and second nozzle sections. The fixed central piece is in communication with a water circulator, and supplies water to the first and second nozzle sections. An open end of each nozzle section is rotatably coupled to an open end of the fixed central piece, and the first and second nozzle sections may be rotated using a manual setting device so as to direct a spray of water in different directions.

A dishwasher includes a washing compartment defined in a cabinet for containing tableware and reserving a predetermined amount of wash liquid on the bottom, a wash pump sucking the wash liquid reserved in the washing compartment and feeding the liquid, a spray nozzle mounted in the washing compartment so as to be vertically moved, to receive the wash liquid fed from the wash pump and to spray the wash liquid to the tableware, and feed liquid pressure changing means for changing a pressure of the wash liquid fed to the spray nozzle during washing the tableware with the wash liquid sprayed from the spray nozzle so that the wash liquid pressure is increased and decreased at a plurality of times, thereby reciprocally driving the spray nozzle vertically at a plurality of times.