High stage, bleed-air regulator valve schematic

(See figure 4-2.) Air from the inlet (13) passes through the filter (14), and then through the reverse-flow check valve (15). The air then enters the reference regulator (16), where it is pressure regulated (as a function of altitude) by an evacuated bellows (1). The air is then passed through a control orifice (6), a shuttle valve (8), and to the actuator section (10) of the high-stage, bleed-air regulator valve to open the butterfly (12). The pressure of the air entering the regulator sensing line (11) with the spring pressure of the actuator section of the valve modulates the valve toward the closed position, as regulated by pressure from the shuttle valve. As aircraft altitude increases, the evacuated bellows expand and cause the reference regulator to close. The ambient vent (5) decreases the pressure to the open side of the actuator section, and thereby allows the spring to close the actuator section. This action also closes the butterfly. When the cross-bleed start solenoid (3) is energized, the reference regulator larger diaphragm (2) is vented to ambient (4). Spring pressure on the reference regulator larger Figure 4-2.-High stage, bleed-air regulator valve schematic. 4-4