Slam-shut safety assembly for providing redundant safety shutoff

An assembly configured to provide redundant safety shutoff in a gas distribution system, comprising:

• a valve body having an inlet, an outlet, and defining a flow path extending between the inlet and the outlet, the valve body including a first slam-shut valve seat defining a first orifice that forms a first part of the flow path between the inlet and the outlet, and the valve body including a second slam-shut valve seat defining a second orifice that forms a second part of the flow path between the inlet and the outlet;
• a first slam-shut safety device coupled to the valve body, comprising:
• a first control element movably disposed within the valve body, the first control element movable along a slam-shut axis between an open first position, in which the first control element is spaced away from the first slam-shut valve seat, thereby allowing fluid flow through the first orifice, and a closed second position, in which the first control element is seated against the first slam-shut valve seat, thereby preventing fluid flow through the first orifice;
• and
• a first valve stem operatively coupled to the first control element;
• and
• a second slam-shut safety device, comprising:
• a second control element movably disposed within the valve body, the second control element movable along the slam-shut axis between an open first position, in which the second control element is spaced away from the second slam-shut valve seat, thereby allowing fluid flow through the second orifice, and a closed second position, in which the second control element is seated against the second slam-shut valve seat, thereby preventing fluid flow through the second orifice;
• and
• a second valve stem operatively coupled to the second control element,
• wherein a first side of the first control element is in fluid communication with a second side of the first control element when the first control element is in the first open position and the first side of the first control element is isolated from the second side of the first control element when the first control element is in the second closed position.

An assembly configured to provide redundant safety shutoff in a gas distribution system, comprising:

• a valve body having an inlet, an outlet, and defining a flow path extending between the inlet and the outlet, the valve body including a first slam-shut valve seat defining a first orifice that forms a first part of the flow path, and the valve body including a second slam-shut valve seat defining a second orifice that forms a second part of the flow path;
• a first slam-shut safety device, comprising:
• a first bonnet coupled to the valve body, the first bonnet comprising a first sleeve extending into the flow path and one or more first flow ports formed in the first sleeve;
• a first control element movably disposed within the first sleeve, the first control element movable along a slam-shut axis between an open first position, in which the first control element is spaced away from the first slam-shut valve seat, thereby allowing fluid flow through the first orifice, and a closed second position, in which the first control element is seated against the first slam-shut valve seat, thereby preventing fluid flow through the first orifice, wherein the one or more first flow ports of the first bonnet fluidly couple the inlet with a cavity formed in the first control element;
• and
• a first valve stem having a first end and a second end, the first valve stem operatively coupled to the first control element at the first end of the first valve stem and to a first trigger mechanism at the second end of the first valve stem, wherein the first trigger mechanism is responsive to pressure;
• and
• a second slam-shut safety device, comprising:
• a second bonnet coupled to the valve body, the second bonnet comprising a second sleeve extending into the flow path;
• a second control element movably disposed within the second sleeve, the second control element movable along the slam-shut axis between an open first position, in which the second control element is spaced away from the second slam-shut valve seat, thereby allowing fluid flow through the second orifice, and a closed second position, in which the second control element is seated against the second slam-shut valve seat, thereby preventing fluid flow through the second orifice;
• and
• a second valve stem having a first end and a second end, the second valve stem operatively coupled to the second control element at the first end of the second valve stem and to a second trigger mechanism at the second end of the second valve stem, wherein the second trigger mechanism is responsive to pressure,
• wherein each of the first and second control elements is pressure balanced.