An air pressure-reducing valve is an automatic control valve. It is designed to reduce a higher inlet pressure to a lower constant outlet pressure regardless of fluctuating flow rates and/or varying inlet pressure. It is a pilot controlled, hydraulically operated, diaphragm actuated globe valve in either the oblique (Y) or angle pattern design. Valve differential pressure powers the diaphragm actuator open or closed. The lower control chamber is connected through a fixed orifice to the downstream pressure, which serves to cushion the closing of the valve.