| 摘要 |
<p>An inner shell (20) is contained, and able to rotate, within an outer shell (10) fixed to a hole (9) in the tub (8); an inner duct (21) facing the tub is fixed to the shell (20), to which there is also joined a tubular element (40) communicating with a first chamber (27) which has its front mouth (41) positioned within the inner duct (21); a unidirectional valve means (44, 45, 46) is applied to the mouth (41) and arranged to close the passage through the mouth (41) when the pressure in the region to the front of the mouth (41) is greater than in the region to the rear; in the duct (21) there is a tubular valving member (50) having an axial cavity containing the front mouth (41) of the tubular element (40) and comprising an intermediate section (50a) which on making contact with the outer surface of the intermediate portion (43) of the tubular element (40) closes the communication between a second chamber (28) and the front mouth (22) of the inner duct (21); the valving member (50) is normally urged into its closure position by elastic means (51) and is able to undergo axial movement as a result of a difference in pressure between the region upstream and the region downstream of said intermediate section (50a). <IMAGE></p> |
