Which device prevents the reverse flow of gas but does not extinguish a fire in the hoses?

The device that prevents the reverse flow of gas while allowing the flow to continue in the intended direction is a check valve. Its primary function is to prevent backflow, ensuring that the gas within the piping system moves efficiently towards its destination without the risk of it flowing backwards. This is particularly important in systems where the integrity of gas flow is critical to safe operations.

In contrast, a flame arrestor is designed to extinguish flames that may propagate back into a hose or fuel system, thereby preventing fires from moving toward the source. This is essential for safety but does not serve the purpose of stopping reverse gas flow. Cylinder gauges and regulators have different functions; cylinder gauges are used for measuring the pressure of the gas within the cylinder, while regulators control the pressure of the gas supplied to the system from the cylinders. Neither of these devices addresses the issue of reverse flow directly, which highlights the unique function of the check valve in gas delivery systems.