Fire hydrant automatic shut-off valve

A fire hydrant automatic shut-off valve for stopping the flow of water once a fire hydrant has been removed from a water supply line comprising, in combination:

• a cylindrical sleeve having an open lower end and an open upper end, the cylindrical sleeve having a pair of outwardly formed pockets disposed below the open upper end, the open lower end receiving a water supply stand pipe therein, the open lower end having a lower mounting plate disposed thereon for securement to the water supply stand pipe, the open upper end receiving an open lower end of the fire hydrant thereon whereby the open lower end of the fire hydrant is in communication with the water supply stand pipe, the open upper end of the sleeve having an upper mounting plate disposed thereon for securement to the fire hydrant, the upper mounting plate having a ring plate secured to a lower surface thereof, the ring plate having an inwardly extending annular flange, the flange corresponding with a depth of the outwardly formed pockets;
• a pair of flaps hingedly coupled with the annular flange of the ring plate of the cylindrical sleeve, the pair of flaps closing to a corresponding horizontal position to effectively seal the cylindrical sleeve to prevent water from flowing from the water supply stand pipe to the fire hydrant;
• and
• a trigger sleeve slidably disposed within the open upper end of the cylindrical sleeve, the trigger sleeve including a hollow main portion having a cylindrical flange extending outwardly therefrom, the cylindrical flange being seated atop the annular flange of the ring plate whereby the hollow main portion extends downwardly to push the pair of flaps into the outwardly formed pockets to allow water to flow freely from the water supply stand pipe to the fire hydrant, the trigger sleeve having a safety line secured thereto, the safety line having a free end secured to the ring plate;
• whereby when the fire hydrant is removed from the standpipe, the flow of water pushes the safety line attached trigger sleeve out of the cylinder so that the flaps move to a closed position, thereby shutting off the water from the standpipe.