What device is used in piping to control the gas supply within a system?

The correct device used in piping to control the gas supply within a system is a valve. A valve serves as a critical component for regulating the flow of gases, allowing for the opening, closing, or partial obstruction of the passageway through which the gas moves. This capability enables operators to manage gas supply adequately, ensuring safety and efficiency within the system.

Valves come in various types, including gate valves, ball valves, and globe valves, each designed for specific applications and flow control requirements. They can help prevent leaks, allow for maintenance to take place without shutting down the whole system, and enable the isolation of sections in case of necessary repairs or modifications.

While regulators also play a role in managing gas flow, their primary function is to reduce and maintain a specific pressure within the system rather than just controlling the flow rate. Fittings and connectors are primarily used to join different sections of piping, but they do not directly control gas flow in the same way valves do. Therefore, a valve is the most appropriate device for controlling the gas supply in a piping system.