| 摘要 |
A rotary slide valve (1) for selective delivery of pressurized air or vacuum to an apparatus (3), which permits a very precise delivery of vacuum or pressurized air through a control port (2), especially to a plenum (16) of an apparatus (3) for introducing a conductive paste into holes (22) in circuit boards (17). Two transfer passages (10 and 11) are disposed in a rotary slide (9) offset by 120 DEG around the axis of rotation, and transfer ducts (12, 13 and 14) contiguous with the rotary slide and communicating with the control port (2) and with inlet/outlet ports (7 and 8) are arranged in a reference plane likewise offset by 120 DEG around the axis of rotation. A vacuum connection (5) and a pressurized air connection (6) are arranged on the housing (4) offset from the reference plane in the longitudinal direction of the rotary slide (9) and in communication with the transfer passages (10 and 11), and in the housing (4) between the transfer duct (12) of the control port (2) and the transfer ducts (13 and 14) of the inlet/outlet ports (7 and 8) closed housing wall sections (23 and 24) are formed which extend over a greater angle than the transfer passages (10 and 11) of the rotary slide (9) such that, alternately, the vacuum connection (5) or the pressurized air connection (6) can be connected to the control port (2) or to the inlet/outlet ports (7 and 8), and in intermediate positions of the rotary slide (9) the transfer passages (10 and 11) are closed off by the housing wall sections (23 and 24).
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