BRAKE SYSTEM CONTINUED
The pressure regulator limits the pressure of the air flowing to the air solenoid valve from the reservoir.
Air pressure flows through a cartridge assembly and is also applied against the lower side of the diaphragm
opposing the thrust of the control spring, holding the cartridge open. When the air pressure against the diaphragm
exceeds the valve setting, the control spring is overcome and the diaphragm is raised, allowing the compensating
spring to close the cartridge. When the pressure drops, the control spring forces the cartridge open and pressure
again passes through the valve. The regulated pressure is adjusted by the adjusting screw, changing the amount
of compression maintained on the control spring.
Figure 17. Cutaway of Pressure Regulator.