What characteristic does the droop of a pressure regulator refer to?

The droop of a pressure regulator refers specifically to the decrease in downstream pressure that occurs when there is an air flow through the regulator. This characteristic is critical because it signifies the regulator's response to varying flow demands. As air flows, the downstream pressure typically drops due to the internal mechanics of the regulator, and this reduction reflects the ability of the regulator to maintain a specified pressure under dynamic conditions.

In scenarios where downstream demand increases, the regulator allows some drop in pressure to occur as it compensates for the flow, which is observed as droop. This behavior is essential for understanding how pressure regulators behave in systems that experience fluctuations in air consumption. It's important for operators to recognize this characteristic so they can ensure that the upstream supply and regulator settings are adequate for the anticipated demand.