U.S. patent number 3,597,134 [Application Number 04/793,350] was granted by the patent office on 1971-08-03 for liquid fuel burning apparatus.
Invention is credited to Frank W. Bailey.
United States Patent |
3,597,134 |
Bailey |
August 3, 1971 |
LIQUID FUEL BURNING APPARATUS
Abstract
Liquid fuel burning apparatus in which air that is free of fuel
is preheated to a temperature above that at which a substantial
quantity of the liquid fuel vaporizes, and then the heated air is
turbulently and violently mixed with the fuel to break up the fuel
mechanically and thermally into finely divided fuel particles in
the hot air. To stabilize this mixture to retard agglomeration of
the finely divided fuel particles it is abruptly cooled by
quenching it by introducing a cooling medium such as atmospheric
air to produce a stable aerosol type suspension suitable for
flowing through a pipe to a distant gas-type burner to be burned in
such burner.
Inventors: |
Bailey; Frank W. (Wayne,
NJ) |
Family
ID: |
25159709 |
Appl.
No.: |
04/793,350 |
Filed: |
January 23, 1969 |
Current U.S.
Class: |
431/141;
431/211 |
Current CPC
Class: |
F23K
5/145 (20130101); F23C 99/00 (20130101); F23C
2700/026 (20130101) |
Current International
Class: |
F23C
99/00 (20060101); F23K 5/02 (20060101); F23K
5/14 (20060101); F23d 011/44 () |
Field of
Search: |
;431/11,2,208,211,207
;158/53F |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Matteson; Frederick L.
Assistant Examiner: Dua; Robert A.
Claims
What I claim is:
1. The system for converting fuel oil and similar liquid fuels into
a stable mixture of finely divided fuel particles and air for
conveniently and efficiently burning the liquid fuel in a remote
burning region comprising a source of air under pressure, conduit
means for preheating said air in the absence of fuel and in the
absence of combustion products, first wall means defining a first
chamber connected to said conduit means, fuel-feeding means
controllably feeding liquid fuel into said first chamber, means
feeding said preheated air from said conduit means into said first
chamber, said means feeding said preheated air into said first
chamber including injection means directed into said first chamber
at an angle producing turbulence and swirling of the heated air in
said first chamber and violently agitating the air therein
converting said liquid fuel into a fine mist suspended in said
heated air, second wall means defining a second chamber spaced from
said first chamber, injection means for injecting said heated air
and mist suspension from said first chamber into said second
chamber, means for admitting a cool quenching medium at atmospheric
temperatures into said second chamber for chilling said mist
suspension, and fuel burning means connected to said second chamber
for igniting and burning said chilled mist suspension.
2. Apparatus for converting fuel oil and similar liquid fuels into
a stable mixture of finely divided fuel particles suspended in air
suitable for burning in a gas-type burner comprising a heated
passage at a temperature above 650.degree. F. for preheating air,
pump means for feeding air free of fuel and free of combustion
products through said heated passage, wall means defining a
premixing chamber, said heated passage communicating with said
premixing chamber for feeding the heated air from said heated
passage into said premixing chamber, fuel feeding means also
communicating with said premixing chamber for introducing liquid
fuel therein, said premixing chamber including a constriction
therein producing a violent swirling movement of the heated air
within said chamber for breaking up the fuel into finely divided
particles suspended in said heated air, said premixing chamber
having a nozzle outlet delivering the suspension of finely divided
fuel particles in heated air to an injector-type mixer for drawing
in atmospheric air at atmospheric temperature to abruptly quench
said suspension to form a stable aerosol-type suspension of said
finely divided fuel particles in air, a remote gas-type burner
device and a passage extending from said mixture to said burner
device for flowing said stable aerosol-type suspension to said
gas-type burner for burning said suspension at said device.
Description
This invention relates to a liquid fuel burning apparatus.
In the burning of liquid fuel such as kerosene, domestic fuel oil,
and similar types of liquid fuel, the prior state of the art has
made necessary the use of processes and apparatus which are
entirely different from those which are used when burning a gas
fuel, such as natural gas, manufactured gas, methane, ethane,
propane, butane, or the like. Thus, gas burning devices as a class,
e.g. domestic gas stoves, domestic gas furnaces and gas room
heaters, gas water heaters, and the like, are quite different in
structure and operation from liquid fuel burning devices as a
class, e.g. kerosene stoves and kerosene room heaters, domestic oil
burners and oil-fired water heaters, and the like. The gas burning
devices have been more compact and less expensive than liquid fuel
devices and gas burning devices have produced a cleaner flame, with
less soot and smog resulting.
It is an object of the present invention to provide a liquid fuel
burning apparatus which enable the use of burner units similar to
those customarily utilized in gas burning devices.
A further object of the present invention is to provide liquid fuel
burning apparatus which produce a clean flame and operate
efficiently while being compact.
In accordance with one aspect of the liquid fuel burning apparatus
which is illustrated as embodying the present invention, fuel-free
air is preheated to a temperature above that which a substantial
quantity of the liquid fuel vaporizes. The resulting heated air is
turbulently and violently mixed with a quantity of the liquid fuel
to break up the fuel mechanically and thermally into finely divided
fuel particles which are thoroughly mixed with the heated air. A
portion of these finely divided fuel particles may be in the vapor
state and the remaining portion in the form of very finely divided
droplets. In order to stabilize this mixture to avoid agglomeration
of the finely divided fuel droplets, the heated air is abruptly
chilled by thoroughly mixing with a cool quenching medium and then
the resulting stabilized mixture is ready to be burned.
Among the many advantages of the present invention are those
resulting from the fact that the apparatus converts the liquid fuel
into a finely divided mixture with a combustion-supporting gas, and
the resulting mixture is stable. That is, the tendency for the
finely divided fuel particles to agglomerate into larger droplets
is largely avoided. As a consequence, this mixture of finely
divided fuel and combustion supporting gas can be readily be burned
in a convention gas burner device. It can also readily be burned in
an internal combustion engine and provides advantages in enabling
less volatile fuels such as kerosene and diesel oil to be burned in
a conventional gasoline engine of the carburetor type, i.e. without
the use of fuel injectors and fuel spray nozzles.
Another advantage of the illustrative embodiments of the present
invention are those resulting from the fact that they include a
combination unitary fuel pump, fuel metering apparatus, compressed
air pump and large flow low-pressure air fan. This combination unit
is adapted to serve as an accessory unit for a large range of
liquid fuel burning devices. Moreover, the fuel metering apparatus
enables precise metering of small fractions of a gallon of fuel oil
per hour by differential pumping action which advantageously
achieves this precise measurement without the use of small orifices
or small pistons. For example, this fuel metering apparatus will
readily operate throughout the range from 2 gallons per hour down
to 0.10 of a gallon per hour and can be adjusted to meter any
desired delivery rate within this range.
In this specification and in the accompanying drawings are
described and shown liquid fuel burning apparatus embodying the
invention, and various modifications of the embodiments of the
invention are illustrated, and it is to be understood that this
disclosure is not intended to be exhaustive nor limiting of the
invention, but is set forth for purposes of illustration in order
that others skilled in the art may fully understand apparatus of
the invention and the manner of their application in practical
use.
The various objects, aspects, and advantages of the present
invention will be in part pointed out and in part will be apparent
from the following description of illustrative embodiments of this
invention, when considered in conjunction with the accompanying
drawings, in which:
FIG. 1 shows a liquid fuel burning apparatus embodying the present
invention utilizing a burner unit similar to a gas-burning
device;
FIG. 2 is an axial sectional view of a compact accessory unit which
serves the combined functions of fuel pump, compressed air pump,
adjustable liquid fuel meter, and large flow low-pressure air
fan;
FIG. 2A is a perspective view of a valve body hub portion of the
apparatus of FIG. 2;
FIG. 3 is a cross section of FIG. 2 taken along the line 3-3
looking downwardly;
FIG. 4 illustrates the differential pump adjustable fuel metering
apparatus;
FIG. 5 is a cross-sectional view of air fan, being a section taken
along the line 5-5 of FIG. 2 looking downwardly; and
FIG. 6 is an exploded perspective view illustrating an eccentric
drive mechanism included in the pump apparatus of FIG. 2.
As shown in FIG. 1 the liquid fuel burning apparatus illustrative
of the present invention includes the step of preheating fuel-free
air to a temperature above that at which a substantial quantity of
liquid fuel 10 vaporizes. This liquid fuel 10 is shown as No. 2
fuel oil being supplied from a suitable oil reservoir 12. There are
two alternative ways in which the air is preheated in this system
of FIG. 1. During the initial brief period of operation when the
apparatus is first being started up the air is preheated by an
electrical heating element 14 which is energized from a suitable
electrical source 16 through a relay switch 18 which is normally
closed. After the system has been in operation for a brief period
to accomplish warmup, then a solenoid valve 20 is opened so that
the air is preheated by means of a coil 22 which is in heat
exchange relationship with the combustion flames 24. As soon as the
heating coil 22 has fully warmed up, the electrical heater 14 is
deenergized by energizing a solenoid 25 so as to open the switch
18.
The resulting heated air at a temperature above 650.degree. F. is
turbulently and violently mixed with a quantity of the liquid fuel
in a first chamber 26 which serves the purpose of mechanically and
thermally breaking up the liquid fuel into finely divided
particles. The elevated temperature of the heated air vaporizes a
substantial portion of the fuel and the remaining portion is
violently sheared and churned to break the fuel up into very finely
divided droplets. This first chamber 26 has an elongated
cylindrical configuration terminating in an output nozzle 27, and
the heated air is introduced into an input region 28 at the
opposite end of chamber 26 from the nozzle 27.
This heated air passes through a constriction 29 which is aimed at
an angle within the chamber 26 to produce a violent helical
swirling movement of the heated air within the chamber 26. The cool
liquid fuel is introduced through fuel inlet means 30 in the form
of a tube which is angled forwardly into the chamber 26, and the
violently swirling air shears and breaks up this fuel. The intimate
and violent mixing of the heated air and cool liquid fuel within
this fuel breakup chamber 26 promotes a very effective and rapid
heating up of the fuel particles. There is a high heat flux from
the swirling air into the fuel particles by conduction and
convection, that is, by relative motion and scrubbing action
between high speed masses of gas. This high heat flux promotes
rapid vaporization and mechanical shearing and breakup of the fuel
into very finely divided droplets. The swirling mixture of heated
air and finely divided fuel (vapor and very tiny droplets) progress
along within the chamber 26 toward the nozzle 27 and issues
therefrom as a jet 32 which is directed into the bell mouth 34 of
an injector type mixer delivering to a burner unit 36 which is
similar to a domestic gas-burning device.
Withing this fuel breakup chamber 26, the ratio of fuel to air is
usually above a stoichiometric ratio thus avoiding any possibility
for combustion to occur within this chamber 26.
As the hot jet 32 enters the funnel shaped entrance 34 it draws in
a large flow 38 of atmospheric air which serves as a secondary air
flow to support combustion and is a cool quenching medium to
stabilize the finely divided fuel particles into a stable
aerosol-type suspension. It is my theory of explanation as to why
this sudden cooling quenching stabilizes the finely divided
particles that it markedly slows down the thermal agitation of the
vapor and finely divided particles. This reduced thermal agitation
reduces the number of collisions between the tiny particles of fuel
and fuel vapor molecules and so it retards the agglomeration of the
fuel into larger droplets. Regardless of whether this is a correct
theory, the flow of cool quenching medium 38 does stabilize the
finely divided fuel particle suspension within the barrel passage
39 of the burner 36. Hence, the tiny fuel particles remain
suspended within the barrel passage 39 and become thoroughly mixed
with the flow 38 of combustion-supporting gas.
This combustible mixture is ignited by ignition means 40 shown as
an electric spark plug. Any suitable ignition means such as a hot
wire, glow plug, or the like, may be used. After the warmup period
the combustion process will continue self sustaining so long as the
jet 32 continues, and so the ignition means 40 may then be turned
off if desired by conventional ignition control mechanism.
The flames 24 pass up within a shroud 42 and are in heat exchange
relationship with the air preheater coil 22. These are cleanly
burning flue flames which are very similar in characteristics to
the flames produced by burning gaseous fuel. The burner unit 36 may
be formed of cast iron, and an adjustable baffle (not shown) is
provided at the entrance to the bell mouth 34 so as to adjust the
quantity of the air flow 38 relative to the jet 32, as is provided
in a conventional gas burner unit.
The system of FIG. 1 includes a compact accessory unit A which
provides the combined function of delivering compressed air,
pumping fuel, metering and delivering a large flow of low pressure
air. This compact apparatus is shown in FIG. 2 and will be
explained further below. It includes a liquid-ring pump P which
produces suction in an intake line 44 and is capable of drawing
either air or liquid fuel or a mixture of both into the intake line
44.
In the system of FIG. 1 the liquid fuel 10, for example such as
kerosene, Nos. 1 and 2 fuel oil, and the like, is drawn up from the
storage tank 12 through a fuel supply line 45 and through a
strainer 46 and a line 47 to a three-way solenoid valve 48 which is
connected by a suction line 49 to the pump intake 44. Air is drawn
into the system through an air intake filter 50 which is connected
by a line 51 to the valve 48. There is an adjustable restriction 52
in an air bleed connection 53 which extends to the suction line 49
to bypass the valve 48, so that a sufficient quantity of air is
always being supplied to be preheated as discussed above. The
solenoid valve 48 is operated by a float 56 (FIG. 2) which operates
a mercury control switch 57 in response to the liquid level 58
within an air-fuel separation chamber 59 which is included in the
compact unit A.
From the liquid-ring pump P the fuel is supplied in metered
quantity through a fuel supply line 60 to the fuel feed tube 30. In
order to keep the fuel cool before it enters the chamber 26, the
tube 30 is surrounded by cooling fins 62.
Fuel-free compressed air is delivered from pump P through an air
supply line 64 and a shutoff valve 66 to a tee connection 67. From
this connection 67 one branch passes through an adjustable
restriction 68 and through a conduit 69 into the region 28. The
conduit 69 is heated by the heater element 14. The other branch 70
extends through the solenoid valve 20 to the heating coil 22 and
returns through a line 71 to the region 28. The valve 20 is
controlled by a thermostat 72 which senses the presence of the
flames and then opens this valve 20, thus bypassing the restriction
68 and conduit 69. An oil bleed bypass connection 73 extends
through a restriction 74 back to the suction line 49.
Instead of igniting the combustible mixture in the Venturi portion
34 of the burner unit 36, the ignition means 40 may be located in
the passage 39 or in the flame region 24, whatever location may be
desired for different applications.
As shown in FIG. 2, the burner accessory unit A includes the
liquid-ring pump P. The pump drives means 80 which may be any
suitable rotary drive means for example such as an electric motor
has its shaft 82 directly coupled by key 83 to a rotating hub
section 84 which is attached to one radial wall 85 of a rotatable
pump casing 86. The wall of the rotary casing 86 has a cup shape
and is clinched onto a hub sleeve member 88 which serves as a
sleeve valve. This hub member 88 rotates about a stationary shaft
90 forming a valve body having a suction intake passage 44 and a
discharge passage 92 extending longitudinally therein, the latter
communicating through a lateral passage 93 with the fuel-air
separating chamber 59.
The fuel-air separating chamber 59 is a sealed chamber being an
integral part of the accessory unit A. This chamber 59 is defined
by a cylindrical housing 94 and a cover 95 which is removably
secured and sealed to the housing 94. The valve body 90 is rigidly
held by the cover 95, and the whole housing 94 is mounted on a base
frame 96. The compressed air supply line 64 is connected to the
chamber 59, and the suction line 49 is connected to the suction
passage 44 within the valve member 90.
A plurality of impeller blades 98 extend radially within the
rotatable casing 98. These blades 98 define sector shaped pockets
100 which are uniformly positioned about the hub sleeve member 88,
and valve ports 108 extend out through this sleeve member 88 into
the pockets 100. These ports 108 provide communication between the
pockets 100 and a pair of recesses 102 and 104 (FIG. 2A) in
opposite sides of the valve body 90 which serve as the intake and
discharge chambers communicating with the passages 44 and 92.
During operation of the pump P, the casing 86 and impeller blades
98 rotate, and the liquid fuel 10 within the pockets 100 is
centrifuged out to form a stable liquid ring having an interface
110 with the air 11 which is being pumped and compressed.
In order to produce a pumping action, an eccentrically positioned
circular rotor 114 displaces the liquid 10 into and out of the
pockets 100. This rotor 114 is mounted on a ball bearing assembly
116 (FIGS. 2 and 2A) which is held by a stub shaft 118 projecting
from the end of the valve body 90. In this embodiment the rotor 114
is freewheeling. As shown in FIG. 2 the perimeter of this rotor 114
slopes inwardly toward the pockets 100, and there are numerous
small square-ended blades 188 projecting out from the perimeter of
the rotor.
These rotor blades 118 perform three functions. (1) They prevent
the liquid fuel from eddying around the edges of the rotor blades
98, thus providing additional stability in the liquid ring and
increasing the total pump displacement efficiency and output
pressure. (2) They prevent a compressional shock wave from
transmitting itself backward through the revolving liquid ring
toward the suction side, thus further stabilizing the liquid ring.
(3) They impart torque hydraulically for rotating the free rotor
114 so that it turns at substantially the same speed as the casing
86, thus avoiding turbulence losses in the liquid.
Although these rotor blades 118 do improve the performance
substantially as explained, this pump will operate satisfactorily
without them, i.e., with a purely disclike rotor, for applications
in which the added simplicity of the pump is desirable and its
lower output pressure and efficiency are acceptable.
A circular baffle plate 120 is clinched onto the opposite end of
the sleeve 88 from the casing 86, and this baffle extends out over
the impellers 98 near to the face of the rotor 114 so as to
separate the liquid in the interior of the pockets 100 from the
rotor 114.
The effective inward and outward motion of the liquid air interface
110 produces a strong suction in the intake recess 102 and intake
passage 44 and produces a strong compression in the discharge
recess 104 and discharge passage 92. This pumps compressed air
through the lateral passage 93 into the chamber 59 and also some
liquid fuel is pumped with the air into this chamber to create a
fuel level 58. When this level rises, the float 56 and switch 57
operate the valve 48 (FIG. 1) to shut off the flow of fuel up
through the line 47. Consequently, only air is then drawn through
the valve 48. There is always a small recirculation of oil through
the bypass connection 73 and restriction 74 so as to maintain the
liquid ring 110 in the rotating casing 86. Conversely, when the
liquid level 58 falls, the valve 48 is again opened to admit the
fuel from the supply line 47 into the suction intake line 49.
In the modified embodiment of the liquid ring pump P shown in FIG.
6 the rotor 114 is positively driven by a drive coupling 122. This
drive coupling includes a first disc 124 which is secured to the
rotating wall 85 and has a diametrically extending groove 125
therein. An intermediate coupling disc 126 of Nylon has radial ribs
127 and 128 on opposite surfaces extending at right angles to each
other. The pair of ribs 127 engage in the groove 125, and the ribs
128 engage in another groove 129 in a disc 130 which is secured to
the rotor 114. Thus, the rotor 114 is positively driven at the same
revolutions per minute as the pump casing 86, and this coupling 122
accommodates the eccentricity of the rotor 114.
The liquid fuel provides lubrication within the pump P for the
rotation of the ported sleeve 88 around the valve body and for the
rotor bearing 116 and also for the positive drive coupling 122, in
the embodiment including this coupling.
In order to provide positive displacement fuel metering of the fuel
being fed to the conduit 30, a differential pump metering mechanism
M (FIGS. 2, 3 and 4) is enclosed within the air fuel separation
chamber 59. There are many advantages in the use of this metering
apparatus M. It avoids mass flow variations of the fuel due to
variations in the viscosity of the liquid and thus continuously
maintains the desired firing rate and prevents sooty inefficient
combustion throughout the range of operation.
This differential pump metering mechanism includes a plurality of
cylinders and pistons which cooperate to provide a controllable and
positively displaced metered volume of liquid at a low flow rate
per hour. This low flow rate is advantageously provided even though
the displaced volume of each of the pistons in their respective
individual cylinders is many many times larger than the metered
output.
The fuel is drawn from the chamber 59 through an intake port 140
and through a spring-biased ball-check valve 142 into an intake
passage 143 communicating with the interior of a cylinder 144
within which is reciprocated a plunger type piston 146. This piston
146 is driven by a nutating eccentric ring sleeve 148 within which
revolves an eccentric 150 secured to the motor shaft 82 by a pin
151 (FIG. 2). The ball-check valve 142 is held in a socket 152
supported by an arm 153 which is secured to a ring 154 surrounding
the mounting 156 of the central bearing 158 for the motor, pump and
fan shaft 82. This mounting 156 is fastened to the lower end of the
housing 94 and is sealed thereto by a seal 160.
In order to accommodate the nutating motion of the eccentric ring
148 as the eccentric 150 revolves, swivel mounting means 162 are
provided for the cylinder 144. The inlet passage 143 is located in
a bushing 162 which is adapted to swivel within the socket 152.
For purposes of adjusting the metered output, as will be explained
further below, the arm 153 can be adjusted in angular position as
indicated in FIG. 3 by turning the ring 154 about the mounting 156.
In FIG. 3 the full-line drawing shows the cylinder 144 at one limit
of its range of adjustment and the dashed-line drawing shows the
cylinder and arm at an intermediate position 144', 153' within the
range of adjustment. A gear sector 164 is engaged by a pinion gear
165 on a vertical shaft 166 which can be turned by an index knob
168 connected through gears 169 and 170 to turn the shaft 166 for
swinging the arm 153 and cylinder 144 about the mounting 156.
As shown in FIGS. 3 and 4, the fuel is pumped out of the passage
143 through a tube 171 and through a ball-check valve 172 connected
to a flexible tube 174 leading to a tee joint 175 connected through
a spring biased ball-check valve 176 to a metered fuel output port
178. As shown in FIG. 2 this port 178 communicates through a
conduit 179 to the fuel supply line 60.
From the tee joint 175 a tube 180 provides a branch flow path
extending to a second cylinder and piston unit including a passage
143a in a swivel bushing 162a supported by a socket 152a on an arm
153a. This arm 153a is rigidly secured to the mounting 156 by means
of a key 182 (FIG. 2) engaging the ring 154a. Thus, the operating
position of the cylinder 144a is secured. From within the passage
143a the fuel can flow past a spring-biased ball-check valve 182
and pass through a return port 183 into the chamber 59. It is noted
that the ball 182 conveniently seats against the lower end of the
swivel bushing 162a within the socket 152a.
In operation, the piston 146a is driven by the same eccentric 150
which drives the piston 146, but their respective strokes are
displaced in time by an amount determined by the adjusted angular
position of the mounting arm 153 relative to the fixed arm 153a.
When the piston 146 is diametrically opposite to the piston 146a,
their strokes are displaced 180.degree. in time, i.e. they are
moving exactly out of phase, and consequently there is no fuel
being fed through the output line 60; all of the fuel is returned
through the valve 182 and port 183 into the chamber 59. This is the
fuel differential return flow, and as will be understood it equals
the total flow when there is no metered output.
As shown in FIG. 3, as the operating position of the cylinder 144
is adjusted in the direction of the arrow 184, by turning the knob
168 (FIG. 2), the phase differential between the strokes of the two
pistons 146 and 146a is progressively reduced from 180.degree.
toward zero. This progressively reduces the flow rate of the
differential return and correspondingly increases the metered
output.
In order to assure the delivery of bypass fuel through the
connection 73 and restriction 74 to the suction line 49, it is
advantageous to connect the return port 183 to the line 73. This
assures that there is always some liquid being fed into the
liquid-ring pump P so as to maintain the desired depth and geometry
of the liquid ring 110.
Among the advantages of this adjustable differential pump fuel
metering apparatus are that the cylinder and pistons may be
relatively large even though the metered output flow is very small.
The apparatus is adjustable over an abnormally wide range down to
zero. The piston and cylinders are of low cost construction and all
of the moving parts are in continuous contact, thus eliminating
chattering or other noise and wear factors. It will be noted that
the flow rate can be adjusted at any time regardless of whether the
burner is in operation or not.
By virtue of the fact that the cylinders 144 and 144a are supported
by bushings defining the inlet and outlet lines, this enables the
driving eccentric 150 to exert maximum mechanical advantage on the
rings 148 and 148a with respect to the swivel joints. Therefore,
these swivel joints can be sealed very tightly against leakage
without imposing a difficult starting or running torque on the
motor 80.
In addition it is noted that because it is a differential volume
metering system, the series of check valves are more reliable,
particularly for high-speed operation. There is a relatively high
throughput rate through all of these check valves, except 176, and
this high throughput rate reduces any tendency for cavitation to
occur and also reduces the susceptibility for fouling due to dirt
particles or lint which might be entrained in the fuel oil or
similar liquid fuel. Also, the large throughput rate enables the
use of standard size check valves because the volumetric
displacement of the movable ball check is small relative to the
large instantaneous fluid displacement.
The accessory unit A also includes a fan 190 (FIGS. 2 and 5)
attached to the end of the shaft 82 for delivering a relatively
large flow of combustion supporting air at low pressure. The air
192 is drawn in through ports 194 in the motor housing 196 which is
secured to the lower end of the pump housing 94. The air flow
passes down through suitable openings in the stator and rotor
laminations 197 and 198 to cool them and the motor windings 199.
The fan blades 200 are adapted to receive an axial flow 201 and to
impell the air out into a scroll 202.
A movable cylindrical damper 204 controls the output flow 205 into
a duct 206 (FIG. 1) by adjusting the relative amount of air passing
through an output opening 207 and through a bypass opening 208. The
arcuate length of the damper 204 is sufficient to block off a
proportion of one opening 207 or 208 which is equal to the
remaining unblocked area of the other opening. Thus, the maximum
cooling flow rate 192 is maintained through the motor regardless of
output flow rate 205.
The duct 206 is connected to an apertured manifold 210 which
supplies a forced draft into the shroud 42 around the flames 24. A
valve 212 can also be used to adjust this flow rate, and a branch
duct 214 directs air over the cooling fins 62.
From the foregoing it will be understood that the various
embodiments of the liquid fuel burning apparatus of the present
invention as described above are well suited to provide the
advantages set forth. It will be appreciated from the foregoing
that many possible embodiments may be made of the various features
of this invention and the apparatus herein described may be varied
in various parts, all without departing from the scope of the
invention, and that all matter hereinbefore set forth or shown in
the accompanying drawings is to be interpreted as illustrative and
not in a limiting sense, and that, in certain instances, some of
the features of the invention may be used without a corresponding
use of other features, all without departing from the scope of the
invention.
* * * * *