Gravity-operated gas shut-off valve

A gas supply line shut-off valve comprising:

• a float including a lower guide region, an intermediate orifice region, and an upper nose;
• a body open at a top end and a bottom end and including a generally cylindrical bore for containing the float, the bore slidably engaging the guide region, the body further including an upper stop shoulder for stopping an upward motion of the float, and a lower stop shoulder for stopping a downward motion of the float, and a valve seat surface for gas sealing against the nose;
• and
• gas line connection means for leak-proof insertion of the body into the gas supply line;
• whereby the shut-off valve may be connected into the gas supply line in a vertical orientation such that, when a certain pressure drop exists across the shut-off valve with a pressure greater below at a certain flow rate, the float may rise and the nose seal against the valve seat surface to stop an upward flow of gas through the shut-off valve;
• wherein the gas line connection means includes a pipe section in which the body is disposed;
• and
• wherein the pipe section is crimped to fix the body within the section.

A method of protecting against spilling gas from a ruptured gas line downstream of a gas meter, during and immediately following an earthquake, comprising:

• providing a gas shut-off safety valve in a vertical section of a gas supply pipe located within or outside a building downstream of a gas meter, said gas shut-off safety valve including
• a unitary float including a lower guide region comprising a gas-guiding portion having a downwardly pointing conical shape and at least three vertically oriented radial fins integrally extending outwardly from said conical gas-guiding portion, an intermediate orifice region, and an upper nose,
• a body open at a top end and a bottom end and including a generally cylindrical bore for containing the float, the bore slidably engaging said fins of the guide region, the body further including an upper stop shoulder for stopping an upward motion of the float, and a lower stop shoulder for stopping a downward motion of the float,
• said valve comprising means responsive to a drop in gas pressure downstream thereof for closing said valve by upward vertical movement of said float and at least partial sealing of said float against said upper stop shoulder.

A method of protecting against spilling gas from a ruptured gas line during and immediately following an earthquake, comprising:

• providing a gas shut-off safety valve in a vertical section of gas supply pipe located within or outside a building downstream of a gas meter, said gas shut-off safety valve comprising
• a float including a lower guide region, an intermediate orifice region, and an upper nose,
• a body open at a top end and a bottom end and including a generally cylindrical bore for containing the float, the bore slidably engaging the guide region, the body further including an upper stop shoulder for stopping an upward motion of the float, and a lower stop shoulder for stopping a downward motion of the float,
• said valve comprisinq means responsive to a drop in gas pressure downstream thereof for closing said valve by upward vertical movement of said float and at least partial sealing of said float against said upper stop shoulder,
• wherein the step of providing the valve comprises providing such a valve with automatic reset means for leaking gas at a small controlled rate when the safety valve is closed, such that the safety valve may be reset by pressure of leaked gas accumulating downstream of the safety valve, whereby the safety valve need not be manually reset.

In a gas supply line in an earthquake prone area, said gas supply line leading from a mains gas supply source and including a vertical section of pipe located within or outside a building downstream of a gas meter, the improvement wherein

• said vertical section of pipe contains a gas shut-off safety valve which constitutes means for limiting gas flow in a downstream and upward direction when there is a break downstream therefrom, said gas shut-off safety valve being disposed in said vertical section of pipe in a vertical orientation and comprising:
• a body open at a top end and a bottom end and having an internal bore wall defining a vertically oriented and generally cylindrical bore;
• a unitary gravity-responsive float including a lower guide region comprising a gas-guiding portion having a downwardly pointing conical shape and at least three vertically oriented radial fins integrally extending outwardly from said conical gas-guiding portion, an upper region having an upwardly pointing conical configuration, and an intermediate orifice region between said lower guide region and said upper region, said intermediate orifice region having an upwardly facing stop shoulder (17), said unitary float being vertically movable within said bore with distal edges of said radial fins being closely adjacent said bore wall;
• said body further including an upper downwardly facing stop shoulder in facing relationship with said upwardly facing stop shoulder (17), and a lower stop shoulder for stopping a downward motion of said float;
• said valve comprising means responsive to a drop in gas pressure downstream thereof for at least partially closing said valve by upward vertical movement of said float with said upwardly facing stop shoulder (17) of said float coming into direct contact with said upper downwardly facing stop shoulder of said body.