Liquid dispensing nozzle having controlled shut-off mechanism

摘要

In an automatic shut-off nozzle, the vacuum chamber, which has its vacuum increased when flow through the nozzle is to be stopped in response to a predetermined condition such as the tank being filled to a predetermined level, for example, has the reduction in the vacuum therein controlled so that the automatic shut-off mechanism cannot be returned to its latching position by the attendant for a predetermined period of time after having been activated. A check valve allows removal of air from the chamber to increase the vacuum in response to the predetermined condition while preventing flow of air into the chamber. The flow of air into the chamber to reduce the vacuum therein must be through metering means so that a predetermined period of time must elapse until the vacuum in the chamber has been reduced by the air flow through the metering means to enable the shut-off mechanism to be latched.