US Patent 7444842 Drum washing machine and method of controlling the same

A drum washing machine including a water tub, a rotary tub rotatably provided in the water tub, a detergent feed pipe having a first end connected to the water tub and a second end disposed at an inlet of the rotary tub, and a detergent feed unit to feed a detergent contained in the water tub into the rotary tub through the detergent feed pipe, wherein the detergent feed unit dissolves the detergent before feeding the detergent into the rotary tub in response to the detergent being a powdered detergent.