An Excess Flow Check Valve is a safety device used in various gas and liquid systems to prevent uncontrolled flow in the event of a sudden increase in pressure or flow rate beyond a specified threshold. These valves come in various designs and configurations, depending on the application. It is designed to automatically close when such an excess flow is detected, helping to prevent gas leaks, liquid spills, or other dangerous situations. They can be installed in horizontal or vertical orientations and may include threaded, flanged, or welded connections. Excess Flow Check Valve used in gas systems, especially in residential and commercial settings, must comply with specific safety and regulatory standards.