| 摘要 |
According to the invention, the shape of each of said chevrons is defined: by two lateral sides (21, 22) having front ends (21A, 22A) that are connected to said nozzle (4, 10) and that, when moving away from the latter, converge towards each other without joining so that the rear ends (21R, 22R) of said lateral walls (21, 22) are spaced from each other; and by a curvilinear transverse line (23.1) connecting the rear ends (21R, 22R) of said lateral walls (21, 22) by forming two rounded side protrusions (24.1, 25.1) separated by an intermediate rounded recess (26.1). |
