In a spring-loaded reducing valve, what determines the position of the auxiliary valve?

In a spring-loaded reducing valve, the position of the auxiliary valve is determined by the position of the controlling diaphragm. This diaphragm reacts to changes in downstream pressure and the spring force applied to it. When the downstream pressure increases, the diaphragm moves in response to that pressure, which in turn adjusts the position of the auxiliary valve. This mechanism ensures that the output pressure remains at a set level regardless of fluctuations in the upstream pressure.

The auxiliary valve operates in conjunction with the diaphragm to modulate the flow of fluid, effectively managing the pressure on the downstream side of the system. Therefore, the controlling diaphragm plays a crucial role in the operation of the reducing valve, as it provides the mechanical movement necessary to maintain the desired pressure setting. Other factors like pressure settings, flow rates, and valve sizes impact overall performance and capacity, but they do not directly govern the positioning of the auxiliary valve.