A pressure regulator apparatus usable with an aerosol supply device containing a fluid includes an inflatable diaphragm unit including an upper surface member, a lower surface member, and a diaphragm chamber formed between the upper surface member and the lower surface member, an output port member having an output cavity and an output port, at least a portion of the output port member is disposed within and in fluid communication with the diaphragm chamber, a valve actuator including an actuator cavity and one or more actuator openings in fluid communication with the output port, at least a portion of the valve actuator is moveably disposed within the output cavity, an input port member having an input port configured to allow the fluid to enter the actuator cavity, at least a portion of the input port member is disposed proximate to the actuator cavity, and an axial flow path extending between the input port and the output port, and configured to allow the fluid to selectively pass in a substantially axial direction therethrough, wherein the valve actuator moves to close and open the input port based on an inflation status of the inflatable diaphragm unit to regulate a pressure of the fluid to be transported from the inflatable diaphragm unit substantially constant.