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Nov. 26, 1946.
H. J. DE N. MCCQLLUM
_
2,41 1,581
FUEL SUPPLY SYSTEM
'
Filed my 17, 1944
4 Sheets-Sheet 1
Nbv. 26, 1946;
H_ J_ DE N, MccQLLUM
"
2,411,581
FUEL SUPPLY SYSTEM
> Filed May 17, ‘1944
_
A Sheets-Sheet 2
NOY- 26, 1946-
I
H. J. DE N. MccoLLuM
’
_ 2,411,581
FUEL SUPPLY SYSTEM
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Nov. .26, 1946.
"H. ‘J. DE N. McCOLLUM
2,41 1,581
FUEL SUPPLY SYSTEM
Filed May 17, 1944
4 Sheets-Sheet 4
Patented Nov. 26, 1946
2,411,581 '
’ UNITED. STATES PATENT OFFICE’
‘ FUEL SUPPLY SYSTEM
Henry J. De N. McCollum, Chicago, Ill.: Thelma
McCollum, executrlx of said Henry J. De N.
McCollum, deceased, asslgnor to Stewart- Warner Corporation, Chicago, III._, a corpora
I tion of Virginia
Application May 17, 1944, Serial No. 535,902
8 Claims.‘ (Cl. 126-116)
My invention relates to fuel supply systems and
self-contained heater adapted to be secured to
-. more particularly to fuel supply systems for in
‘ temal combustion heaters of the kind used on
aircraft.
_
the skin of an aircraft or to a panel which is
mounted in a- window opening or other opening
in an aircraft wall. This heater comprises a
sheet metal housingv I ll secured to a wall 12 of an
aircraft cabin, or to a panel which may be in
Internal combustion heaters used on aircraft
are subject to variation in operation resulting
from changes in altitude of the aircraft and re
serted ina window openingor other opening in
suiting changes in the fuel mixture supplied by
such a wall, The wall I2 is provided with open
the ordinary carburetor under these varying con
ings through which the ventilating air ram i4 and
ditions of altitude. Numerous and various expe 10 exhaust pipe l6 project. A ring it surrounds the
dients have been adoptedrin order to provide a
opening for the ventilating‘ air, and screws 20
fuel feeding system for such heaters to overcome
extend through this ring, wall I! and housing Ill,
this objection to the ordinary carburetor. These
and engage nuts 22 attached to the inner wall of
various expedients are frequently complicated,
expensive, cumbersome, heavy, require frequent
,adjustment or repair, or are otherwise objec
tionable.
.
this housing. A second ring 24 surrounds the opening for the exhaust pipe, and screws 26 ex
tend through this ring, wall l2 and housing It,
and engage nuts 28 attached to the inner wall of
An object of my‘ invention is to provide a new
this housing; An asbestos or other suitable gasket
and improved fuel supply system which is simple,
may be interposed between' the wall i2 and I
inexpensive, compact, lightweight and capable of 20 ‘30
housing iii.
providing a uniform mixture of fuel and air under
varying conditions of altitude and speed.
Another object of my invention is to provide a
fuel supply system having new and improved
A heat exchanger, indicated generally by ref
erence character 32, is located in the housing It!
and is mounted on partitions 34 and, 36, which
form supports for this heat exchanger and also
means to prevent ?ooding.
'
.25 serve to direct air ?ow therethrough. A cylindri
Another object of my invention is to provide
cal combustion chamber 38 is- attached to one
a fuel supply system which automatically com;
end of the heat exchanger 32 by way of a ?aring
pensates for variations in altitude and which may
(throat 40 and supplies the tubes 42 of the heat‘
readily be applied to existing aircraft heaters.
exchanger with hot products of combustion.
Another object of my invention is to provide 80 After
these products of combustion have passed
a new and improved altitude compensating fuel
lengthwise of the tubes 42 and have given up
supply system whichcan readily be built into air
substantially all of their heat, to these tubes and
craft heaters without appreciably increasing their
to
inlet header 44, the cooled products of com
size, weight or cost. or in any wise detracting
.- bustion enter an exhaust manifold 48 and pass
‘from their normal operation.
86 therefrom into exhaust pipe it. g In addition to
Other objects and advantages will become ap
the inlet header 44, the heat exchanger alsoin
parent as the description proceeds.
cludes an outlet header 48, the tubes 42 being
In the drawings:
'
‘
mounted inboth of these headers.
Fig. 1 is a longitudinal vertical section through
When the aircraft is in motion, the ram M sup
an aircraft heater to which my inventionhas 40
plies ventilating air to a space 50 surrounding the
been applied. ‘This ?gure is taken on the line
combustion chamber 38. This ventilating air
i-l of Fig. 2:‘
Fig. 2 is a transverse vertical section taken on
?owsv horizontally through ' the space 50 and
‘ around the combustion chamber 88 and absorbs
Fig. 3 is a horizontal section taken on the line
heat from the walls of this combustion chamber.
This ventilating air then ?ows into an elongated
chamber 52 at one side of the heat exchanger
the line 2-2 of Fig. 1;
3-; of Fig. 1;
Fig. 4 is a partial vertical longitudinal section
of a modi?ed form of my invention; and
32, and thence horizontally through the heat ex
I Fig. 5 is a top plan view of the modified‘ heater
changer to a corresponding chamber 54 on" the
installation of Fig. 4 showing in cross section the 60 opposite side thereof. The ventilating air ab
wall or other support to which the heater is at
sorbs heat from the heat exchanger as it passes
tached.
>
‘
Theparticular embodiment of my invention
which I have illustrated in the drawings of this
thereover,‘ and this heated ventilating air ‘?ows
from chamber 54 into a space 56 surrounding the
exhaust manifold 46. The ventilating air passes
application is shown as being applied to-a unitary, 65 fromthe space“ into the aircraft cabin or other
2,411,581 ‘
3
space to be heated by way of an outlet, 60 provided
in an end wall of the housing Ill.
The heat exchanger 32 is illustrated as having
thick header plates’ 44 and 48 and tubes 62 having
thick walls and as being of the type described
more fully and claimed in my copending appli
cation Serial No. 516,648, filed January 1, 1944.
The self-contained, unitary heater which I .have
described is like that disclosed and claimed in
my copending application Serial'No. 516,649, filed
January 1, 1944.
Combustion air is admitted through a second
ram 62 formed by the curved inlet end of a com
bustion air pipe 66. The ram 62 is located in the
,
As ‘the aircraft changes altitude, the pressure
of the combustion air delivered to the vVenturi
tube will change and the mass of air ?owing
through this tube in a given time will likewise .
change. The fuel vapor delivered to the jet ‘I6
is subject to the same pressure variations caused
by altitude changes as the combustion air with
whichthis vapor is to be admixed. The density
of both gases varies with variations in this pres
sure, and the proportions of fuel and air in the
combustible mixture formed in the Venturi tube
.10 remain the same for all changes in altitude.
The internal combustion heater, therefore, oper
ates ef?ciently and evenly at all altitudes.
In this connection, it will be noted from Fig. 1
that the top of the coil I06 is at substantially
same opening in the aircraft skin I2. The com
the same elevation as the top of the liquid in
bustion air pipe 64 extends transversely of one
the ?oat bowl 90, so that the liquid head in
_ end of the combustion chamber 38, whereby com
this ?oat bowl is not relied upon to supply fuel
bustion air ?owing through this pipe is preheated,
to the Venturi tube ‘I0. That portion of the tube
20
before being mixed with fuel, to form a com
I04 between the coil I06 and Venturi tube ‘I0 is
bustible mixture. The other end 66 of the com
inclined upwardly to a slight extent so that the
bustion air pipe 64 communicates with an elbow
rate of vapor delivery by the jet ‘I4 is solely a
“which delivers the preheated combustion air
function of the vacuum created at the throat
tothe inlet end of a Venturi tube 10 formed in
of the Venturi tube by combustion air ?owing
a casting ‘I2 attached to one wallof the combus
therethrough.
tion chamber 38. A fuel jet ‘I4 delivers fuel
Air ?ow into the rams I4 and 62 is produced
vapor to the throat of the Venturi tube 10 where
by forward motion ‘of the' aircraft relative to
this fuel vapor is mixed with combustion air to
the air through which it is traveling. The greater
form a combustible mixture. The outlet end of
the speed the greater the quantity of air deliv
30
the Venturi tube ‘I0 is connected to an induction
ered by these rams and the greater the pressure
tube 16 having a curved outlet end ‘I8 located
at which this air is delivered. The pressure at
in the combustion chamber. This combustible
the
air inlet of the Venturi tube ‘I0, therefore,
mixture is ignited by an electrical igniter 80
varies not alone with variations in altitude but
having a hot wire 82 located in a pocket 84 pro
vided by the casting ‘I2 and communicating with 35 also with variations in air speed of the aircraft
to which the heater. is attached. All variations
the combustion chamber 38 by way of passages
in pressure at the air inlet of the Venturi tube
86 and 88.
‘
are transmitted to the ?oat bowl 00 by pipe I00,
A novel aspect of my invention resides in the
so that the pressure ',on the fuel thereinchanges
fact that vaporized fuel, instead of liquid fuel, is
with the variations 5in pressure at the Venturi
supplied to the jet ‘I4. This vaporized fuel is 40 tube
inlet, regardless of whether these pressure
subject to the same variations in pressure caused
variations are caused by changes in altitude or
by altitude changes as is the combustion air
changes in air speed, or both. My novel‘ fuel
which creates the suction in the Venturi tube to
supply system is, therefore, compensated for
draw vaporized fuel thereunto. .I shall now de
changes in both air speed and altitude ,and
45
scribe the mechanism by which the foregoing
delivers a combustible mixture whose richness is
novel feature of my invention is accomplished.
not changed by variations in either speed or alti
The jet ‘I4 is supplied with fuel from a ?oat
bowl 90 having the usual ?oat 92 controlling a
tude.
The essential difference between the modi?caé
needle valve 04 regulating admission of- fuel to
of Figs. 4 and 5 and the embodiment of Figs.
the ?oat bowl through an inlet 96. A pipe 98 50 tion and
3 resides in the fact that in Figs. 1, 2 and '
1,
2
connects the inlet 96 with any suitable source of
3 the fuel line I04 has a coil I06 exposed to the
fuel. A pipe I00 connects the top of the ?oat
ventilating air which vaporizes the fuel, whereas
bowl with the elbow 68, through whichv the com
in the modi?cation of Figs. 4 and 5 the fuel line
bustion air ?ows in passing from the' rain 62 to
65 has a portion‘ extending into the combustion I
ram I4, and both of these project through the
the Venturi tube 10. This pipe I00, therefore,
chamber and the fuel is vaporized by heat ob»
insures maintenance in the ?oat bowl of the same
tained from this chamber. Referring to Figs. 4 '
pressure to which the combustion air is subjected
and 5, it will be seen that in this form of my
just prior to its entry into the Venturi tube 10.
invention the ?oat bowl 00 is located at the for
The ?oat bowl 90 has a fuel outlet ?tting I02
ward/or combustion chamber end of the heater.
through which .the liquid fuel leaves this ?oat 60 The‘
fuel line N41; has a reversely bent portion
bowl. This outlet ?tting is preferably provided
I06'o
which extends through the combustion
,with a restriction I03. A tube of copper‘ or other.
chamber 30 and into the ?aring throat 40. This
suitable material I04 connects the outlet ?tting
portion I00a is exposed to the hotv products of
I02 with the jet ‘I4. This tube I04 extends into
combustion and absorbs sumcient heat therefrom
65
the ventilating air space 50 and has a coiled por
to'vaporize the fuel contained in this portion of
tion I06 located therein. The ?ow of heated ven- '
the fuel line I04a so that the jet ‘I4 receives only
tilating air over ‘that portion of the tube ‘I04
which is within the space 58 vaporizes theliquid ~
vaporized fuel instead of the usual liquid fuel.
The pipe I00awhich connects the top of the ?oat
fuel in this‘ portion of the tube so that-the fuel
with the elbow 08 is shorter than the cor
?owing from the coiled portion I06 of the tube 70 bowl
responding pipe I00 of the vprevious embodiment
_
Thevjet
.14
is
made
by
"104 iisein vaporized form.
but performs the, same function of maintaining
screwing a small plug I08 into the outlet end of
a pressure in the ?oat, bowl corresponding at
the tube I04 and by providing this plug with-Ya
all times to the pressure at .the air inlet of
small ori?ce through which the vapor passes intov
the throat of the Venturi tube'10'.
_
.
the Venturi tube ‘I0. Since the operation of that
-
2,411,581 '
form of my invention shown in Figs. 4 and 5 is
the same as the operation of the previous em
bodlmentpit is unnecessary further to describe
the operation of the modi?cation of Figs. 4 and 5.
In each of the two embodiments of my inven
tion the heating coil which vaporizes the fuel be
ture to said combustion chamber, means’ includ
ing‘ a ram for supplying combustion air to said
Venturi tube, a ?oat bowl for liquid fuel, a fuel
jet in said Venturi tube, a pipe connecting said
?oat bowl with said jet, said pipe .having a part
exposed to ventilating ‘air leaving said heat ex
changer whereby fuel in said pipe is vaporized
fore this fuel reaches the jet 14 receives heat as a
result of heater operation. When the heater is
before it reaches said jet, and a second pipe con
?rst started, no heat is available to vaporize the‘
necting the inlet end of said Venturi tube with
fuel and liquid fuel is supplied to the jet 14. This 10 the top. of said ?oat bowl.
jet is made of appropriate size to deliver the de
2. An aircraft heater comprising walls forming
sired amount of vaporized fuel when the heater
a combustion chamber, a heat exchanger receivis operating normally'and unless special means ‘ ing hot products of combustion fromsaid com
were provided a great excess of liquid fuel would
bustion chamber, means including a ram for cir
?ow through this jet when‘ the heater is ?rst
culating ventilating air over said heat exchanger,
started and would ?ood the heater. I have pro
a Venturi tube for supplying a combustible mix
vided special means to prevent such ?ooding
ture to said combustion chamber, means includ
when the heater is ?rst started and this anti
\ ing a ram for supplying combustion air to said
?ooding means constitutes an important feature
Venturi tube, a ?oat bowl for liquid fuel, a fuel
of my invention.
20 jet in said ‘Venturi tube, a pipe connecting said
I have previously ‘pointed out that the outlet
float bowl with said jet, said pipe having a part
?tting it? for the float bowl is provided with a
extending into said combustion chamber whereby ’
restriction ass.
This restriction is smaller than ,
the jet ‘it and when the heater is ?rst started the
restriction H33 ratherthan the jet ‘it determines
the quantity of fuel supplied to the heater. Since
it is desirable to supply a rich mixture for start
ing, the restriction I03 is so designed that it will
furnish a quantity of fuel slightly in excess of that
required when the heater is in normal operation.
As soonv as the heater attains normal operating
temperature, the fuel in coil I06 or IBM is vapor
ized and thereafter the jet 14 determines the
quantity of fuel supplied to the combustion
chamber.
'
,
4
In a heater designed to have a heat output of
10,000 B. t. u. per hour, the Venturi tube 10 would
fuel in said pipe is vaporized before it reaches
said jet, and a second pipe connecting the inlet
end of said Venturi tube with the top of said
?oat bowl.
3; An aircraft heater comprising walls forming
a combustion chamber, a‘heat exchanger receiv
ing hot products of combustion from said combus
tion chamber, means including a ram for cir
culating ventilating air over said heat exchanger, '
a Venturi tube for supplying a combustible mix
ture to said combustion chamber, means includ
ing ‘a ram for supplying combustion air to said
Venturi tube, a ?oat bowl for liquid fuel, a fuel
jet in said Venturi tube, a pipe connecting said
?oat‘ bowl with saidiet, said pipe having a part
be given a throat diameter of about %" and the > - exposed to heat from said heater whereby fuel in
tube I04 would have an outside diameter of 1A".
said pipe is vaporized before it reaches said jet,
The jet 14 would have a diameter of about .055" 40 and a second pipe connecting the inlet end of
and the restriction I03 would have a diameter of
said Venturi tube with the top of said ?oat bowl.
about .015"~. In such a heater the pipe I00 or
4. An aircraft heater comprising walls form
- 100a would be considerably smaller-‘than that ining a combustion chamber, a heat exchanger
dicated in the drawings and would probably be
receiving hot products of combustion from said
formed of copper tubing having an outside diam
combustion chamber, means including a ram for
eter of 1A" or 1%".
’
circulating ventilating" air over said heat ex
It will be apparent from the foregoing descrip-_ ,
changer, means for supplying a combustible mix
tion taken in connection with the accompanying
ture to said combustion chamber, means includ-_
drawings that applicant’s novel fuel supply sys
ing a ram for supplying combustion air to said
tem incorporates no more operating parts than r second-named means, a ?oat bowl for liquid fuel,
does the ' conventional carburetor. There is
said second-named means including a fuelout
nothing about this new and improved fuel supply
let, a pipe connecting said ?oat bowl with said
system which should cause any additional service
outlet, said pipe having a part exposed to heat
problems or which would add appreciably to the
from said heater whereby fuel in said pipe is
cost or weight of the heater. Likewise, there is
vaporized before it reaches said outlet, and a‘
no increase in bulk over a conventional fuel sup
‘second pipe connecting the ‘inlet end of said
ply system of the carburetor type, and no addi
second-named means with the top of said ?oat
tional manufacturing or assembling problems are
presented by my invention. In other words,‘ my
5. An aircraft heater comprising walls forming
invention provides a simple, eflicient and inex 00 a combustion chamber, a heat exchanger re
pensive solution for the problem of altitude and
ceiving [hot products of combustion from said
speed compensation in aircraft heaters;
combustion chamber, means including a ram for
While I have illustrated and described only two
circulating ventilating air over said heat ex
embodiments of my invention, it is to be under
changer, a Venturi tube for supplying a com
stood that my invention may assume numerous
bustible mixture to said combustion chamber,
other forms and includes all ‘modi?cations, varia
means including a ram for supplying combustion
tions and equivalents coming within the ap
air to said Venturi tube, a ?oat bowl for liquid
pended claims.
'
.
fuel, a fuel jet in said Venturi tube, said jet being
I claim:
'
located slightly above the liquid level in said bowl,
1. An aircraft heater comprising walls forming 70 a pipe-connecting said ?oat bowl with said jet,
a combustion chamber, a heat exchanger receiv
said pipevhaving a part exposed to heat from
ing hot products of combustion from said com
said heater whereby fuel in said pipe is vaporized
bustion chamber, means including a ram for cir-=
before‘ it reaches said jetpand a second pipe
culating ventilating air over said heat exchanger,
connecting the inlet end of said Venturi tube
0 Venturi‘ tube for supplying a combustible mix- _ 76 with the top of said ?oat bowl.
2,411,581
7
6. An aircraft heater comprising walls forming
a combustion chamber, a heat exchanger receiv
ing hot products of combustion from said com
bustion chamber, means including a ram for cir
culating ventilating air over said heat exchanger,
8. Venturi tube for supplying a combustible mix
ture to said combustion chamber, means includ
necting said ?oat bowl with said jet, said pipe
having a part exposed to heat from saidlheater
whereby fuel in said pipe is vaporized before it
reaches said jet, 9. second pipe connecting the
inlet end of said Venturi tube with the top of said
?oat bowl, and means forming a restriction in
said ?rst pipe limiting ?ow of liquid fuel to said
jet when the heater is started.
8. An aircraft heater comprising walls forming
Venturi tube, a float bowl for liquid fuel, a fuel '
jet in said Venturi tube, a pipe connecting said 10 a combustion chamber, a heat exchanger receiv
ing hot products of combustion from saidcom
?oat bowl with said jet, said pipe having a part
bustion chamber, means including a ram for cir
exposed to heat from said heater whereby fuel
culating ventilating air over said heat exchanger,
in said pipe is vaporized before it reaches'said
9. Venturi tube for supplying a combustible mix
‘jet, a second pipe connecting the inlet end of
said Venturi tube with the top of said ?oat bowl, 15 ture to said. combustion chamber, means includ
ing a ram for supplying combustion air to said,
and means preventing excess ?ow of liquid fuel
Venturi tube, a ?oat bowl for liquid fuel, a fuel
through said jet when the heater is started.
jet‘ in said Venturi tube, a. pipe connecting said
'7. An aircraft heater comprising walls forming
?oat bowl with said jet, said pipe having a part
a combustion chamber, a' heat exchanger re
ceiving hot products of combustion from said 20 exposed to heat from said heater whereby fuel
in said pipe is vaporized before it reaches said
combustion chamber, means including a ram for
jet, a second pipe connecting the inlet end of
v_ circulating ventilating air‘ over said heat ex
said Venturi tube with the top of said ?oat bowl,
changer, a Venturi tube for supplying ‘a com
and means forming a restriction between said
bustible mixture to said combustion chamber,
means including a ram for supplying combustion 25 jet and float bowl, said restriction being smaller
than said jet.
air to said Venturi tube, a ?oat bowl for liquid
‘
HENRY J. DE N. McCOLLUM.
fuel, afuel jet in said Venturi tube, a pipe con
. ing a ram for supplying combustion air to said
.
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