| 摘要 |
<p>Object presence in a gap is detected by a fluid jet issued across the gap toward a sensor opening and interruptible by the object. Supply and outlet passages communicate with the sensor opening. Jet interruption permits supply passage fluid to exit from the sensor opening and aspirate the outlet passage. The uninterrupted jet impacts supply passage fluid just outside the sensor opening, producing a back pressure in the opening which directs supply passage fluid into the outlet passage. Supply passage fluid pressure is selected to prevent entry of the unblocked jet into the sensor opening, thereby assuring flow of only clean supply fluid through the outlet passage.</p> |
