| 摘要 |
<p>The system for filling a tank with liquid - for example petrol - includes a pipe which is connected to a vertical filler pipe extending down into the tank. A float mounted in a guide tube is arranged to move within the tank to sense the level. When the supply of liquid is first delivered, the pressure opens a large spring biassed valve allowing a flow of liquid into the tank. When a certain level is attained, the float rises and blocks a smaller pipe which until then allows liquid to escape from the space behind the main valve. Once the escape of liquid from this area stops, the pressure builds up from the supply via a central pipe, until the pressure on either side of the main valve is equalised, and it consequently closes.</p> |
