A typical PRV consists of several key components the inlet and outlet ports, a diaphragm, a spring, and an adjustment knob or screw. The diaphragm is crucial as it senses pressure changes; when the downstream pressure rises above the set point, the diaphragm compresses the spring to close the valve partially, restricting the flow of gas. Conversely, if the downstream pressure falls below the set point, the spring expands, opening the valve to allow more gas flow.