| 摘要 |
<p>In order to reduce the risk of inadvertent removal from an internally-pressurized cask or keg of a valve-type closure through which the contents are discharged, the valve body (15, 16) has rotationally-mounted on it an axially-trapped sleeve (23) which is threaded into the usual fixed socket (11) on the cask or keg. As the sleeve is screwed in, a peg (24) on the body enters a channel (25) in the socket to guide the body axially into the socket. On attempted removal of the sleeve (23) without a special tool to restrain rotation of the body in the unscrewing direction, the body tends to rotate in the unscrewing direction and the peg (24) enters a blind-ended passage (27) so preventing removal of the closure. However, the body moves axially sufficiently to open a gas-relief passage from the cask or keg to atmosphere.</p> |
