TM 9-4310-397-14
SECTION III PRINCIPLES OF OPERATION
1-13. PRINCIPLES OF OPERATION.
The rotary air compressor is diesel engine driven through a direct connected coupling. The compressor is capable of
delivering 125 cfm (3.54 cm/m) compressed air at 100 psi (7.03 kgs cm). The information that follows references the
air/oil flow found in figure 1-2.
a.
Air Cleaner. Filters airborne particles from the incoming air to minimize equipment damage from contaminated
air entering the inlet housing.
b.
Inlet Housing. Provides control over the compressor intake and engine speed. The COMPRessor UNLOADER
AND IDLE CONTROL can be used to manually close the compressor inlet or allow for the system pressure to
automatically regulate the inlet. An external linkage controls the engine speed as necessary.
c.
Compressor. Uses rotating vanes in an eccentric cylinder to compress atmospheric air up to the required 125
cfm (3.54 cm/m) compressed air at 100 psi. (7.03 kgs cm).
d.
Oil Separator. Receives the compressed air/oil mixture from the compressor and separates the oil through a
labyrinth and filter element. Oil that collects inside the filter element is drawn into the inlet housing. Oil that collects in
the bottom of the oil separator is drawn into the thermal bypass.
e.
Thermal Bypass. Senses the oil temperature as it enters and ports the flow directly to the oil filter if the
temperature is below 150° F (66° C) or through the oil cooler first if it is above 150° F (66° C).
f.
Oil Cooler. Cools the oil prior to being filtered and sent back to the compressor.
g.
Oil Filter. Filters particles from the oil to minimize equipment damage from contaminated oil entering the
compressor.
h.
Pressure Regulator. Opens at pressures above 100 psi (7.03 kgs cm) and closes at pressures below 100 psi
(7.03 kgs cm), this regulates the system pressure by automatically operating the inlet housing. When the pressure
regulator is closed, the inlet housing opens the compressor inlet to raise system pressure. When the pressure regulator
is open, the inlet housing closes the compressor inlet to lower system pressure.
i.
Minimum Pressure Valve. Closes the discharge from the filter separator if the compressed air demand is great
enough to drop the system pressure below 60 psi (4.2 kgs cm2). Closing the discharge at pressures below 60 psig (4.2
kgs cm2) prevents oil from being carried out of the oil separator and into the hose reel and double discharge valve.
j.
Blowdown Valve. Relieves system pressure to atmosphere when the compressor stops. Suction from the inlet
housing keeps this valve closed.
k.
Safety Valve. Opens at 125 psi (8.79 kgs cm) to relieve system pressure to atmosphere.
1-6
