A Comprehensive Guide to Excess Flow Check Valves and its Features

Excess Flow valves also referred to as velocity check or seismic valves, are created to shut down immediately after a sudden surge of flow. An excess flow valve is basically an in-line valve via which liquid or pressurized gas flows in both the directions. They shut down after excessive discharge of vapor or liquid caused due to the breaking of the pipe system. After the flow rate has exceeded the setting of the valve, it continues to remain closed till the time system pressure becomes stable. In case the flow doesn’t exceed, the valve’s setting won’t close.

A leading number of excess flow check valve manufacturers are manufacturing innovative and affordable valves, which are available in different configurations, flow rates and sizes, based on the vessel’s construction and the desired flow rate that are crucial for completing the process. Read on to find out more about excess flow check valves and their unique features.

Excess flow check valves

The excess flow check valves can be easily purchased in numerous pressure materials, classes, end connections and flange designs. These valves undergo stringent check in a certified flow laboratory for performance and durability. The excess flow valve is basically a spring loaded check valve that closes only after flow of vapor or liquid via the valve produces sufficient force or flow for overcoming the strength of the spring that helps in keeping it open. Each of these valves is available in multiple sizes as well as flow rates based on the reason for which they’re being used. It is important to determine the purpose for which the valve will be used prior to installing it. The excess flow valves are utilized for different fluids as well as processes including excess flow check valve for lpg gas, anhydrous ammonia, butane, nitrogen air, anhydrous chlorine, water etc.

They allow vapor or liquid to flow in different directions. The flow is usually controlled in one specific direction as each of the valves come with an arrow. Hence, when the flow in the desired direction surpasses the already determined flow rate, the excess flow check valve closes automatically.

The disk of the valve remains in an open position with the help of a spring. After the vapor or liquid flow results in a drop in the pressure across the disc of the valve that is exceeding the present flow rate, the disk of the valve closes against the valve’s opening to hinder the flow of the liquid or vapor. This valve disk remains closed till the time the pressure between both the downstream and upstream sides of the flow check valve equalizes. After the pressure equalizes, the flow check valve will open automatically. As a result, when the line’s broken or ruptured, the pressure towards downstream won’t equalize and the valve won’t open till the time the line’s been repaired.

To sum up, excess flow check valves are ideal for handling fluid components for oil and gas, chemical as well as petrochemical industries as well as water blast organizations.

Sudarshan is the author of this article on lpg vaporizer manufacturers .