Cadillac 60 Series 1963 Shop Manual page 396

HEATING AND AIR CONDITIONING
13-15
compressor. The valve body contains three ports;
the evaporator gage port on the inlet side of the
valve, and two ports on the outlet side for the
external equalizer line and the oil bleed line.
The suction throttling valve is used to maintain
evaporator pressure at a particular setting. The
valve is controlled in operation by two opposing
forces separated by a diaphragm: evaporator
pressure on one side of the diaphragm is opposed
by spring pressure and atmospheric pressure on
the other side.
When evaporator pressure rises above the set-
ting, this pressure is exerted against the piston
and, by means of four small bleed holes in the
piston, against the diaphragm. This evaporator
pressure overcomes both the spring pressure
and atmospheric pressure, causing the piston to
open until a balanced position is reached, at which
evaporator pressure returns to the setting
desired.
When evaporator pressure drops below the set-
ting, spring pressure and atmospheric pressure
together overcome evaporator pressure, causing
the piston to close down until the evaporator
pressure reaches the setting desired.
The suction throttling valve on 60 and 62 series
cars is designed to maintain a constant evaporator
pressure of 33 psi, except during periods of max-
imum cooling. When maximum cooling is desired,
vacuum is applied to decrease the effect of spring
pressure, thus decreasing the evaporator pres-
sure. This design is permitted by the new Air-
Mixture heating-Air Conditioning system, where
the temperature valve, Fig. ,13-16, regulates the
temperature of the air discharged into the pas-
senger compartment.
Two suction throttling valves are used on 75
series cars--one with each evaporator. The
valves used on 75 series differ from the valve
used on the 60 and 62 series in that they are de-
signed to increase the effect of atmospheric pres-
sure when vacuum is applied, thus increasing
evaporator pressure. This design is used as the
suction throttling valves control the temperature
of the air being dischargechby regulating the low
pressure side of the system.
With the suction throttling valve at throttled
conditions (at medium to high engine speeds)
when maximum cooling is desired, evaporator
pressure is maintained at 30 psi in order to keep
the temperature of the core from dropping below
32°F. This prevents condensation on the core
from freezing and blocking the air flow through
the core.
Externally Equalized Expansion Valve
An externally equalized expansion valve is
mounted on the bottom front of the evaporator
Shaft
Shoe Disc
Ball \ Shell
Suction Reed
Front Discharge
Valve Plate
Oil Pum|
Gears
Rear Head
Clutch Plate and
Hub Assembly
.Seal Seat
Pulley Bearing
Pulley
Oil Pick-up Tube
/ \ Thrust i Thrust Race
Oil Sump Rear Race \
Cylinder Half
T h r u s t B e a n n
9
Front Head
Clutch Coil
and Housing Assembly
Fig. 13-13 Air Conditioner Compressor Cross Section View