| 摘要 |
<p>A pressure relief valve and especially such a valve for use in the lid or other part of a cooking vessel. It is a feature of the valve that it automatically opens in response to certain pressure conditions, and requires manual resetting to the closed condition. The valve incudes a closure member (15) which is movable between valve open and valve closed positions, and a configuration dependent hold-open member (16) which is operative, in one configuration, to bias the closure member (15) into the open position and to hold it in that position. The hold-open member (16) is annular and has a frusto-conical form in the operative configuration. An actuator (14) is operable to move the closure member (15) from the open position to the closed position, and the hold-open member (16) responds to that movement by adopting a reversed conical configuration. The hold-open member (16) is subjected to stress when moving between the two conical configurations and that stress is at least partially relieved at each of the open and closed positions of the valve. Because of that stress relief, the hold-open member (16) has an oppositely directed biasing effect on the closure member (15) in each of the two conditions of the valve.</p> |
