Pressure Regulator
The pressure regulator (fig. 2-4) is a
diaphragm-operated, pressure-reducing valve located
downstream from the fluid separator and telltale oil
filter. The diaphragm position governs the valve
opening, maintaining a constant reduced output
pressure. Compressed air is used to load the diaphragm.
This is accomplished by bleeding air from the line
through two needle valves, the body needle valve and
the dome needle valve, into the air dome. These two
needle valves are used to seal off or trap air in the air
dome at a pressure approximately equal to the desired
outlet pressure.
Since the air dome pressure is
approximately equal to desired outlet pressure, a O- to
100-psig meter is installed, which constantly monitors
air dome pressure. This pressure is factory adjusted to
80 psig, which is the inlet pressure to the dehydrator
unit.
Since the dome is sealed after loading, a change in
temperature will cause a slight change in dome pressure,
with a corresponding shift in outlet pressure. ‘his outlet
pressure shift amounts to about 1 psig for each 5 degrees
Fahrenheit.
The pressure regulator is a balanced pressure
regulator that is actuated by static gas pressure in a
sealed dome. There is a flexible diaphragm between the
Figure 2-4.-Pressure regulator.
2-6
