Two stage automatic shut off valve

A float actuated valve assembly for preventing overfilling of a liquid storage tank comprising an elongate hollow drop tube adapted to be mounted in a vertically extending position in the interior of said storage tank to conduct liquid into said tank a valve housing fixedly mounted at lower end of said tube, a float slidably received on said drop tube above said housing for upward and downward movement in response to a rise or fall of the level of liquid in said tank, valve means including a valve member mounted within said housing for pivotal movement between an elevated open position and a lowered closed position to control the flow of liquid from said drop tube into said tank, valve actuating means coupling said valve member to said float to locate said valve member in said open position when the level of liquid in said tank is at or below a selected first level and to locate said valve member in a closed position when the level of liquid in said tank is above a selected second level above said first level, a vertically elongate locking pin slidably received in a vertical bore in said housing and projecting upwardly from said housing to an upper end located above an upwardly facing surface on said float, first stop means fixed on said pin in overlying relationship to said surface on said float to raise said pin in response to a rise in the level of liquid in said tank and to lower said pin in response to a drop in the level of liquid in said tank, said locking pin projecting downwardly into a locking position in the path of movement of said valve member away from said open position when the level of liquid in said tank is below said first level and elevated to a position clear of said path when said level of liquid is at or above said first level, locking means operable in a first position to accommodate vertical movement of said pin in either direction and operable in a second position to which said locking means is biased to lock said pin against downward movement, and second stop means fixed to said actuating means for locating said locking means in said first position when the level of liquid in said tank is at or below said first level and for accommodating biased movement of said locking means to said second position in response to a rise in the level of liquid in said tank above said first level.

A float actuated overfill prevention device for preventing overfilling of a liquid storage tank via a drop tube projecting downwardly into the interior of said tank from the top of the tank, said device comprising a valve housing fixedly mounted on the lower end of said drop tube and having a vertical flow passage therethrough for discharging liquid from said drop tube into said tank at a level substantially below the top of said tank, a hollow cylindrical float received on the exterior of said drop tube above said valve housing for vertical sliding movement relative to said drop tube in response to variations in the level of liquid in said tank, shutoff valve means in said housing movable between an open position accommodating flow through said flow passage into said tank and a closed position restricting flow through said flow passage into said tank, said valve means comprising a flapper plate mounted in said housing for pivotal movement about a horizontal axis at one side of said passage between an elevated substantial vertical open position at one side of said passage and a lowered substantially horizontal closed position blocking at least a portion of said passage to establish a restriction to downward flow therethrough, actuating means including an elongate actuating rod coupled at its lower end to said flapper plate and projecting upwardly from said housing and a second vertical bore through said float to an upper end projecting above a first upwardly facing surface on said float, said first and second bores accommodating vertical sliding movement of said rod relative to said housing and said float, first stop means fixed to said rod at a location above said first upwardly facing surface for limiting upward movement of said float relative to said rod, second stop means fixed to said rod below said float for limiting downward movement of said float relative to said rod, said actuating means being operable upon upward movement of said float in response to a rise in the level of liquid in said tank above a first predetermined level to pivot said flapper plate from said open position to said closed position and to pivot said plate from said closed position to said open position upon downward movement of said float in response to a lowering of the level of liquid in said tank below said first predetermined level, an elongate rod like locking pin having a lower end located within said housing and projecting upwardly through a third vertical bore in said housing and a fourth vertical bore through said float to an upper end projecting above a second upwardly facing surface on said float, said third and fourth bores accommodating vertical sliding movement of said pin relative to said housing and said float, third stop means fixed to said pin above said second upwardly facing surface for limiting upward movement of said float relative to said pin to locate the lower end of said pin in a position blocking movement of said flapper plate from said open position when the level of liquid in said tank is at or below a second predetermined level lower than said first predetermined level and to lift said lower end of said pin upwardly to a position clear of said flapper plate upon a predetermined rise of said level of liquid above said second level, locking means operable upon closure of said flapper plate to lock said locking pin against movement downwardly relative to said housing and operable upon movements of said flapper plate to said open position for releasing said locking pin.