Abstract: For the square-like washing area in dishwashers, the circular covering formed by the general sprays will cause the insufficient washing at the four corners, so the subject of spray coverage performance is put forward. Based on the principle of spatial separation of TRIZ theory, the corner spray can form supplementary washing coverage to the corners of the square area. Through the derivation of the calculation formula of the increased coverage rate, the curve of the increased coverage rate changing with the wing length ratio of corner spray is studied and analyzed, and the optimal range of the span length ratio is obtained. Then, different designs of single and multiple corner spray were analyzed with the benefit of unit water consumption. Finally, the four-wing sprays in two rear corners of the square area was determined, and the washing coverage test and the standard cleaning test were carried out. The experimental results show that the washing coverage performance was improved while it can hold the effect of strengthening washing, so the cleaning performance of corner spray was expanded and improved.

Key words: Corner spray, Coverage performance, Area coverage rate, Benefit analysis, Cleaning test