| 摘要 |
5 There is provided a debris blowing and/or vacuum appliance (10: 30). The appliance (10; 30) comprises a body (12; 32) including a fluid inlet (20; 46), a fluid outlet (28; 42) for exhausting fluid externally of the body (12; 32), a volute (100) located in a flowpath between the fluid inlet (20; 46) and the fluid outlet (28; 42) and a centrifugal impeller (200) located within the volute (100) and rotatable by a motor (204) to generate i0 a flow of fluid between the fluid inlet (20; 46) and the fluid outlet (28; 42), the volute (100) comprising volute walls (122) delimiting a volute outlet region (128) in communication with the fluid outlet (28; 42) and a diffuser (114) located immediately downstream of the centrifugal impeller (200) between the centrifugal impeller (200) and the volute outlet region (128). The diffuser (114) comprises an annular channel surrounding the 15 centrifugal impeller (200) and has substantially constant radial width such that the impeller (200) is radially spaced from the volute walls (122) by at least the width of the diffuser (114). By providing such an arrangement, the efficiency of the impeller can be improved. Therefore, an appliance having improved performance for blowing and/or vacuuming dirt and debris can be provided without, for example, increasing power 20 consumption. This is of relevance to battery powered appliances, where improved efficiency may provide stronger performance and a longer operating run time for a given battery size and charge. 102 20128 I |
