| 摘要 |
<p>A valve unit, in particular for use at the suction inlet of a pumping apparatus, comprises a ball valve having a ball (2) and a seat (1) for controlling the flow of liquid between an inlet (18) and an outlet (19). A spring (3) forces the ball (2) into the seat (1). An actuating pin (8) projects through the valve seat (1) and contacts the ball (2). The actuating pin (8) is designed such that liquid can pass alongside the pin through a passageway (22). The armature (14) of a solenoid (12) can be pushed against a membrane (10) which is in contact with the actuating pin (8) so that the ball (2) is lifted from the seat (1) and the valve is opened. Since the opening and the closing of the valve unit can thus be actively controlled, the switching operation of the valve unit is very well reproducable resulting in a more uniform flow of the liquid delivered by a pumping apparatus connected to the outlet (19) ofthe valve unit.</p> |
