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VE RTICA L
STAB
R. H. STAB
L. H. STAB
R. H. WING
GAGE
L. H. WING
SHUTTLE
VALVE
VACUUM MANIFOLD
OVERBOARD
CONTROLVALVE
OVERBOARD
FILTER
OIL SEPARATOR
VACUUM
PUMP
Figure
3-33.
Lightweight
Automatic
(Pump Driven)
Surface
Deicer
System
With Goodrich
Valves
combination
overboard
-
pressure
relief
valves; the
while
the
switch
is held in engagement;
when
the
energized
control
valves
port
pressurized
air
to
the
switch
is released,
the
boots
will return
to
the
pressure
sensitive
shuttle
valves
which,
in
turn,
vacuum
hold-down
condition.
shut off
the
vacuum
normally
applied
to
the
boots
and allow pressurized
air
to
inflate
the
boots.
A
The oil
separator
in each engine
accessory
section
deicer
system
pressure
of 15
to
18
psig
is
main-
recovers
oil in
the
pump
output
air;
the
oil is
then
tained
by
the
pressure
relief
function
of
the
control
returned
to the
engine
sump.
An air filter
is con-
valves.
When
the
control
valves
are de-energized
by
nected
to the
pressure
outlet
of each control
valve
the
timer,
the
shuttle
valves
port
the
boot inflating
to
remove
foreign
particles
and any remaining
oil
air
overboard
through
the
control
valves;
system
from
the
deicer
boot inflating
air.
The deicer
sys-
vacuum
is
then
reapplied
to
the
boots.
,
tem
also contains
a
gage in
the
cockpit
to
register
system
pressure
and a standard
reset
type
circuit
Through
the
electric
timer
the
solenoid
operated
breaker
to
protect
the
deicer
system
electrical
control
valves
cause
all of
the
boots
to
be inflated
circuit.
simultaneously;
therefore, the
system
is
described
as a "single-inflation"
type.
Since
the
control
valves
operate
simultaneously
and are
positive
in posi-
tioning
from
"dump"
to
"deicer
pressure,
" the
sys-
SYSTEMS INCORPORATING
TAVCO
CONTROL
tem
will operate
with one engine-driven
vacuum
VALVE ASSEMBLIES
pump inoperative,
which permits
operation
of
the
deicer
system
on one engine,
When
the
deicer
system
three-position
switch
is
actuated,
a solenoid
operated
pilot valve
builds
up
pressure
against
the
pressure-vent
shuttle
spool,
Both MANUAL
and
AUTOMATIC
positions
of
the
causing
the
boots
to
be
pressurized.
When
the
deicer
switch
are momentary.
Momentary
engage-
pressure
reaches
approximately
one
psig,
a ball
ment of
the
AUTOMATIC
position
will automatically
poppet
closes
off
the
vacuum
port
and
the
pressure
inflate
the
deicer
boots
for five
to
eight
seconds
continues
to
increase
until regulated
boot pressure
before
they
resume
the
vacuum
hold-down
condition.
is reached.
The pressure
relief valve
is an integral
The MANUAL position
will
inflate
the
boots
only
part
of
the
control valve assembly.
3-49
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