When high-pressure gas enters the valve, it pushes against the diaphragm and compresses the spring. As the diaphragm moves, it adjusts the valve opening, allowing only a set amount of gas to pass through to the downstream system. If the output pressure begins to rise above the desired level, the diaphragm moves against the force of the spring, closing the valve slightly to reduce flow. Conversely, if the outlet pressure drops, the diaphragm moves down, opening the valve and allowing more gas to flow through. This dynamic interaction ensures that the pressure remains stable, adapting to fluctuations in demand.