| 摘要 |
<p>In a piston valve, two valve chambers are interconnected by an axial bore in the piston through which liquid flows continuously. As the liquid pressure in one chamber increases, it moves the piston and closes the valve. The closing movement is controlled in the following manner: a liquid receiving chamber receives liquid from that chamber and trickles it through a nozzle when a pilot valve is open, and is shut off from the chamber to increase the pressure therein gradually when the pilot valve is closed. A tiltable bucket is mounted to receive the trickling liquid and has a pilot valve opening cam for closing the pilot valve when the bucket has been filled with liquid trickling from the nozzle and for opening the pilot valve when the bucket is in the opening position ready to receive the liquid from the nozzle.</p> |
