March 28, 1944» H. J. AUE N. MccoLLuM Erm. «2,345,140

March 28, 1944»
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H. J. AUE N. MccoLLuM Erm.
«2,345,140
AIRCRAFT HEATING APPARATUS
Filed Sept. 5,’1942
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2,345,140
Patented Mar. _28, 1944y
' vmural)y .STATES PATENT o FFICB
mimic’
HEATING APlFiâRATUS
Henry J. DeN. McCollum' and Imm A. Williams,
Jr., Chicago, Ill.; said Williams as_slgnor to
>Stewart-Warner Corporation, Chicago, Ill., a
corporation of Virginia
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Application September 3, 1942, Serial No. 457,1`52
_ scams.
(cuasi-112.3)
Our invention relates generally to aircraft
description, reference becilng hadto the accom
heating `apparatus and more particularly to - Danying drawing, in whi
means for controlling the operation oi such ‘ap
Fig. 1 is a diagrammatic view of a lsystem for i v
operating a heater of the internal combustion , ,~
`_ paratus.
It has become common practice to utilize a
type:
form of such system;
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’ Fig.l 3 is a central longitudinal sectional'view
oi' one or more internal combustion type heat
ers for heating the cabin and other parts of thev
v
Fig. 2 is a diagrammatic view of a modified
portion of the fuel and air mixture supplied to
'the .aircraft engine by its supercharger as `a
source of _combustible mixture for the'operation/
of the valve used in the system of Fig. l.
As shown diagrammatically in Fig. 1, a heat
_Wer I0 of the internal combustion type is sup
l0 "
aircraft. The products of combustion from the
heater have ordinarily been discharged over
board, but in _some 'instances have. been returned
plied with a combustible mixture through a con
duit I2 from the high pressure side of a )super
charger M. The supex'charger- Il is the` regular
to the inlet of the supercharger. Under some
conditions of operationof the airplane it is de l5 airplane supercharger used to supply the explo
tween the inlet and the outletjof the supercharger
sive mixture to the engine of the airplane through
its discharge conduit i6. The mixture for_ the
to cause dow of the combustible mixture to the "
heater and to 'cause the; discharge of the products 4
hureting means through a conduit- I8, the iiow
of combustion therefrom, while under other con
ditions of operation the pressure diiîerential be
through which is controlled by a throttle valve
20'. The products of combustion from the heater
sirable‘to utilize the> differential pressureïbe
‘ tween the pressure side of the supercharger and
the atmosphere »is suillcient for satisfactory op-`
eration of the heater.
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Although under substantially all conditions of
airplane operation, the heater will> operate sat
isfactorily when it is connected between the _out- `
supercharger i4 is supplied thereto from a car;-Ä
fiow therefrom through a discharge conduit 22.> i
through a-'three-way diverter connection 2t. The
-.connection 24 is adapted-,to conduct the flow
from the conduit 22 either through a conduit 26
leàdmamto the conduit la or through a pipe.,
2l which leads overboard of the airplane,pref-
let and the inlet of the engine supercharger.
era’bly at a point where the pressure is subatmos
there is a slight disadvantage in permanently
pheric when- the airplane is in ilight.
connecting the heater in this manner. Even 30 The heater I0 is of the internal combustion
though the products of combustion entering the
type, and may be of any suitable construction
’inlet of the supercharger form but a small per-l
in which the burning gases andthe products of“
centage of thel ñow through the supercharger,
combustion are hermetically sealed trom the ven
and the dilutionY of the mixture supplied to the
tilatin’g air, such, forexample, as shown -in the
engines therefore does not noticeably affect en 35 copending application of Hr J. DeN. McCollum,
gine operation, such-dilution must have some ef- l
Serial No. 447,345, ñled June 17. 1942.
fect, and it is therefore advisable to avoid such
The three-way connection 2l. as shown in
admixture of the products of combustion from"
Fig. 3, comprises a body 30 forming a T to one
>the heater with the chargé flowing to the engine
opening of which the conduit 22 is connected by
whenever possible.
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suitable fittings. The other two openings in
It is therefore an object of our invention to
- the body 30 are adapted to be closed by check
lprovide an improved means whereby the prod'
valves 3l and 3,2, each comprising a seat 34, which .
~ucts of combustion oi an internal combustion type
heater may alternatively be discharged to the'
` atmosphere or to the inlet of the engine super
‘ may be in the form of a stamping held in place '
by a coupling fitting 36.- -A disc-shaped valve
45_ 38 is-guided for‘engagement with the seat 34 by
a centering pin l0, which projects through' an
A further ’object is to provide .an improved
charger.
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aperture in a cross piece _4_2, which may be formed
integrally with the valve seat 3,4.- 'I'he pin 40 also '
of combustion from an internall -I combustion
heater to cause these products -to flow to the inlet 60 -serves to hold a spring-centeringvspider 43 to the
means_for automatically diverting the products
of the engine supercharger whenever the;pres.-„
v sure differential between the outlet ofthe super
_charger and the atmosphere is insuillcient to v.
assure satisfactory operation of the heater.
Other objects >will appear from the following
rear face of the valve, this spider serving- to hold v
in place one end cfa conical compression' spring
M_, the other end oi which is seated. against a
i shoulder IB formed/in the coupling fitting Il.
.The valve seat stamping “is clamped between>
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2,3%,149
a pair of annular gaskets 48,.upon screwing the
coupling ñtting 33 in place.
by the products of combustion flowing againstv
_
and past it until the pressure differential upon
its opposite sides becomes slightly less than that
required to open the valve initially.
tically, except that the spring 44 of the valve 32
is preferably stronger than the spring- 44 of the 5
From the foregoing, it will appear that irre
valve 3|. For example, the spring for the valve ' spective ofthe operating conditions of the air
3| may be just strong enough to bias its valve
plane and its engine, the heater will be main
tained in operation, since the products of com
disc 38 to closed position (when not subjected
to pressure), irrespective of the position in which
bustion vwill be withdrawn either through the
the valve 24 may be mounted in the airplane, 10 conduit 28 or the conduit 26, depending upon .
the relationship between atmospheric pressure
while the spring for the valve 32 may be ,com
pressed suiiiciently so that this valve will open
and the pressures at the inlet and outlet of the
supercharger.
only when it is subjected to a predetermined
differential pressure, in the order of 2" to 5"
It is not essential that the valve which diverts
Hg., depending upon the characteristics of the 15 the products of combustion be automatically op
engine and of the airplane: with which it is used.
erable, since in some installations such diversion
is required but infrequently. Under som'e operat
In the operation of the system of Figs. 1 and 3,
the valve 3| will open to discharge the products
ing conditions, and in some installations of the
-heating system, the pilot will prefer to continue
of combustion from the heater overboard when
ever the pressure within the valve 24 is slightly 20 to have the products of combustion discharged
overboard rather than diverting them to the inlet
above atmospheric pressure, for example, .an
of the supercharger. For such installations, the
inch or two of water above atmospheric pressure.
system of Fig. 2 may be employed. In this ligure,
Thus, whenever the supercharger |4 is supply
parts similar to_ those previously described with
ing the mixture to the heater at a sufficiently
high pressure to maintain the pressure within 25 reference to Figs. 1 and 2 bear similar reference
characters. In this system, the automatic divert
the body of valve 24 slightly above atmospheric
er connection 24 is replaced by a lmanually oper
pressure, the productsl of combustion will be
able three-way valve 50, which may be of any
discharged past the valve 3| to the atmosphere.'
suitable construction, but for simplicity is illus
There are many occasions when the absolute
pressure at the inlet to the supercharger is below .30 trated as having a hinged vane 52 operated by a
handle 54. When in the position inwhich the
atmospheric pressure by an inch or two of ‘mer
vane 52 and handle 54 ’are shown in full lines in cury, while the pressure at the outlet of the
Fig. 2, the products of combustion will be dis
supercharger is sufiiciently above atmospheric
charged overboard through the conduit 28, where
pressure for satisfactory operation of the' heater.
Under these circumstances, it is desirable to con 35 as, when the vane 52 and handle 54 are moved
to their dotted line. positions, the products of
tinue to discharge the products lof combustion
combustion will be discharged through the con
past the valve 3| to the atmosphere, and it is for
duit 28 into the induction conduit I8 of the super
this reason that the spring of the valve 32 is made
charger |4. Depending upon the location of the
su?ciently strong to prevent opening of the valve
when these relative pressure conditions prevail. 40 valve 50, it may be operated through a suitable
Bowden wire or by electromagnetic control means
However, when the pressure at the outlet of the
instead of by the handle 54 shown in Fig. 2.
supercharger decreases to a value such that the.
In using> the system of Fig. 2, the valve will
pressure in the body of the valve 24 is no longer
normally be in its full-line position so that the
slightly above atmospheric pressure, the valve
products of combustion are discharged overboard,
32 will open and the products of combustion from 45 but
under such conditions where high output of
the heater thus discharged into the induction
heat from' the heater is essential, and such high
pipe I8 of the supercharger |4.
output is not obtainable due to the low difference
It will thus be .seen that the products of com
in pressure between the pressure side of the
bustion from the heater will be discharged to the 50 supercharger |4 and the atmosphere, the pilot
»atmosphere whenever this manner of discharge
may shift the valve 52 to its dotted-line position,
will result in satisfactory operation of the heater, ' thus utilizing the full diiîerential pressure across
but that when the absolute pressure at the outlet
the supercharger |4 to assurev an adequate supply
of'the supercharger drops to such a low value
of combustible mixture to the heater. '
that discharge to the atmosphere is no longer 55 While we have shown and described a particu
possible, the products of combustion will flow
lar embodiment of our invention, it will be ap
past the valve 32 into the inlet ofî the super~
parent to those skilled in the art that the essen
charger. It is not essential that there be this ' tial features thereof rnay be embodied in varied
difference in the diilîerential pressures at which
and modified forms.' We therefore desire to in
the valves 3|, 32, operate, since, even if the
clude within the scope of the following claims,
springs 44 are of equal strength, the product» of
all such modiñcations and variations of the in
combustion from the heater will be discharged
ventlon whereby substantially the results of the
to the atmosphere throughout a large proportion
invention maybe obtained through the use of
The valves 3| and 32 may be constructed iden
‘ of the time that the system is in operation.
substantially the same or _equivalent means.
However, with the springs v44 of different 65 We claim:
strength, as described above, the products oi'
1. In an airplane having a supercharger for
combustion will be discharged to the atmosphere
supplying a mixture of fuel and air to the engine,
a greater proportion of the time than would be
the combination of a heater of -the internal com
the case if the springs 44 were of equal strength.
bustion type, means for conducting a fuel and
It will be noted that when _either the valve 3| 70 air mixture from the pressure side of said super
or the valve 32 is open, the area of its valve
charger to said heater for combustion therein, a
disc 38 which is exposed to the pressure of the
conduit for conveying products >of combustion
products of combustion in the valve body is in
from said heater, a three-way connection having
creased, so that after one of the valves has been
one port receiving products of combustion from
opened, it will tend to be held in open position 75 said last named conduit, a conduit connecting
2,345,140
the'inlet of said supercharger to a second, port _
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ond and in` said third conduits,- said check valves
being arranged to open to pass the products of
of said three-way connection, a conduit connect
ing the third port of said three-Way connection
v combustion to whichever of said second-and third
to the atmosphere, valve means controlling ñow
conduits is at the lower pressure.
from the three-way connection to the super
3. In an airplane having a supercharger for
charger inlet conduit responsive to the differen
supplying a mixture of fuel and air- to the en’gine,
tial of pressures therebetween, and separate
the combination of \a heater ofthe internal com
valve means controllingv ñow from the three-way
bustion type, means for conducting a fuel and air
connection to the atmosphere conduit responsive
mixture from the pressure side of said super
to the diiîerentials in pressure therebetween.
10 charger to said heater for combustion therein, an
2. In an airplane having a supercharger for
exhaust conduit for conveying products of com
supplying a mixture of fuel and air to the engine,
bustion’from said heater, valve means connected
the combination of a heater of the internal coni
’ to receive products of combustion from said ex
bustion type, means for conducting a fuel and
haust conduit, a suction conduit connected to the
air mixture from the pressure side of said super 15, inlet of said supercharger, a discharge conduit
charger to said heater for combustion therein, a
connected to the atmosphere, and means respon
ñrst conduit for conveying «products of combus
sive to the relative pressures in said suction and
tion from said heater, a valve body having three
discharge conduits to control the operation of
ports, one port receiving products of combustion
said valve means and cause the products of com
from said first conduit, a second conduit connect 20 bustion to flow through said suction-conduit or
ing the inlet of said supercharger to a second
through said discharge conduit, whichever is at
port of said valve body, a thirdconduit connect
the lower pressure.
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V
ing the third port of said valve body to the
< HENRY J. DEN._MCCOLLUM.
atmosphere, and loaded check valves in said sec
j LYNN A. WILLIAMS, JR.

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