| 摘要 |
<p>A pump has a housing defining a pump chamber and having a shaft opening. An impeller shaft extends through the shaft opening and is sized to define a gap between the impeller shaft and the shaft opening. An impeller is attached to the shaft inside the pump chamber. The impeller includes a first set of impeller blades for transporting fluid through the pump chamber and a second set of impeller blades for creating a pressure force which pushes fluid away from the shaft opening. The pump with sealless shaft prevents fluid from leaking through the gap, and therefore is particularly suited for use in a tank-type vacuum cleaner capable fo collecting both dry material and fluid. The gap is used in such an application to prime the pump, thereby discharging fluid collected in the tank.</p> |
