When the emergency system is in operation, air from cylinder 1 is admitted through the orifice in valve member 2 and through bushings 3 and 4 into chamber a. Here the air bends diaphragm 5 to the right, compressing spring 6. At this, rod 8 is moved to the right by spring 7, allowing valve member 2 to seat on bushing 3 as shown. This shuts off air flow from the cylinder to chamber a whose port d leads to the emergency system. As the compressed air is used up in the system, the pressure drops in chamber a and rod 8, actuated by spring 6, opens valve member 2 again. The pressure of the air in the emergency system is controlled by the force exerted by spring 6. Ball valve 9 serves to recharge the cylinder with compressed air.
$4270$CHP,Rg$