Aerosol spray can with safety valve uses nonreturn valve integrated in fill hole to shut this independent of bung screw when can is pressurised.

摘要

The over-fill safety device (2) uses a prefered screw (4) in the suitably threaded fluid fill hole (3) and a non-return valve (11) integrated in the hole (3) closes off the fill opening independent of the screw (4) when the can is filled with pressure gas (8). Water is prefered as fluid and pressure gas is compressed air. Once gas is introduced through the valve (7) to fill out the space above the fluid level the nonreturn valve as part of the overfill safety device blocks off the fill hole (3) by its ball (15) and straddling stops (13,14).