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Патент USA US2405807

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Aug. 13, 1946.
‘
‘ P. ARANT
‘
I 2,405,807
BURNER CONTROL SYSTEM
Filed Sept. 24, 1941
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Patented Aug. 13, 1946
2,405,807
UNITED STATES- PATENT OFFICE
2,405,807 ’
BURNER CONTROL SYSTEM
1
Perry Arant, Alhambra, Calif., assignor to Clay
ton Manufacturing Company, Alhambra, Calif.
Application September 24, 1941, Serial No. 412,193
26 Claims. (Cl. 158-28)
This invention relates to control means for fuel
burners of the atomizing type and more particu
larly to a control system for a burner whose fuel
is electrically ignited.
2
fuel such as high octane gasoline which produces
a particularly hazardous explosive mixture.
A still further object of the invention is to pro
vide either ‘manual or‘fully automatic control
More specifically, the invention relates to a 5 means for a fuel burner which is easy to install,
relatively inexpensive, and above all dependable
will avoid all danger of explosion or ?re.
and fool-proof.
Nearly all explosions in burners operating with
In brief, the present invention comprises a con
atomized fuel are the direct result of ignition fail
trol system having a bi-metallic electrode or
ures, either momentary or complete. Ignition 10 thermostat-electrode arranged so that it serves as
failures may be the direct result of improper set
one of the spark electrodes and is initially sub
ting of the spark gap, carbonizing of one or both
jected to the heat produced by a high voltage
of the electrodes, a cracked electrode permitting
spark. In standard oil burner installations the
partial short circuiting, a wet or moist high ten
ignition transformer usually has an output of
sion wire, etc. Momentary ignition failures are 15 about 10,000 volts at 23 milliamperes. A drop
dangerous because they usually occur after the
of as little as 1500 volts in this output due either
fuel has been sprayed into the combustion cham
to a resistance which may be caused by a partial
ber, thereby forming an explosive mixture which
short circuiting or by a line-voltage drop would
is ignited upon recurrence of the spark, In some
prevent the bi-metallic or thermostat element
control system for spark-ignited burners which
instances, especially with partial short circuiting 20 from expanding to the extent desired even
though it be continuously subjected to the heat
due to moisture, the heat of the spark will dry
of the spark for an hour. Carbon on the tip of
the electrodes is another common fault and if
this occurs to the extent that a 25% reduction in
dangerous if it occurs at a time when the walls 26 the proper spacing of the electrodes is made, the
spark gap will give off insu?icient heat to actuate
of the combustion chamber are still hot, or when
the thermostat.
a piece of glowing carbon remains in the combus
A push rod is associated with the thermostat
tion chamber, and fuel is supplied to the burner.
element and is arranged to actuate an ignition
This source of danger presents itself when an at
tempt is made to start the burner immediately 30 switch and a fuel control switch upon expansion
of said thermostat. These switches are of the
after having been cut off and the spark completely
mercury type and the ignition switch may be con
fails, but the combustion chamber is still hot
sidered a “break” switch since it produces a break
enough to cause the fuel to flash.
in the circuit upon being actuated, and the fuel
The principal object of the invention is to pro
vide a control system for a burner which will 35 control switch may be considered a “make’f switch
since it makes or completes a circuit to a solenoid
positively prevent explosions and eliminate the
operated
fuel control valve upon being actuated.
danger and/or injury which usually result there
These switches are associated with a double-pole
from.
relay and an ignition transformer and are ar
Another object of the invention is to provide
40 ranged in a circuit so that upon the closing of a
a control system which will prevent fuel from
main switch, either manually or automatically, a
being introduced into the combustion chamber
circuit to the spark electrodes will be completed
when said chamber is in a hot condition.
and sparking will commence. This spark heats
Another object of the invention is to provide a
the bi-metallic electrode and the arrangement is
burner control system which will scavenge the 45 such that if said spark is of sufficient intensity to
combustion chamber of combustible gases before
ignite the fuel it actuates the thermostat-elec
fresh fuel can be introduced thereinto.
trode, whereby the fuel control switch is “made”
Still another object of the invention is to pro
and fuel is allowed to flow to the burner nozzle.
vide a burner control system which will prevent
After fuel ignition has occurred, the thermostat
fuel from being supplied to the burner except 50 is further expanded by the heat of combustion of
when the ignition spark is of sufficient intensity
the fuel to “break” or open the ignition switch.
to ignite the fuel.
The circuit is such, however, that current con
A further object of the invention is to provide a
tinues to be supplied to the electrodes so long as
burner control system for general use with oil or
the main switch is closed.
gas furnaces, or furnaces burning highly volatile 65 If the spark gap, for any reason, fails to pro
out the moisture quickly, permitting a delayed
spark at the time the combustion chamber is full
of vaporized fuel. Complete spark failure may be
2,405,80’?
3
in which the ignition is cut off after the fuel has
duce the heat necessary to actuate the thermo
been ignited.
stat-electrode, no fuel whatever will be supplied
Referring to Fig. l, the numeral 5 indicates a
to the burner and hence there is eliminated not
gasoline engine which is connected by a coupling
only the danger of explosion but the ?re hazard
6 with a generator ‘I capable of supplying any
which would result from the introduction of fuel
suitable
alternating current, for example, 110
into the combustion chamber.
volts A. C. at 60 cycles. Current from the gen
Once the ignition switch has been opened and
orator ‘l is carried by the lines 8 and 9, respec
the current to the relay has been cut off, as by
tively. A main switch It is associated with the
opening of the main switch, no spark can be pro
duced until the thermostat-electrode has had an 10 lines 8 and 9 and controls the flow of current
from the generator to the remainder of the ap
opportunity to cool and contract and thereby
paratus. The switch l0 may be a manually actu
allow the fuel control switch to resume its initial
ated switch or a thermally responsive switch de
“break” position and for the ignition control
pending upon whether a manual or automatic
switch to assume its original “make” position, in
the order named. Accordingly, one of the im 15 control is desired.
‘While a gasoline engine and generator have
portant features of the present invention is the
been illustrated for supplying current to the con
inclusion of a dual-purpose blower, which blows
trol system, it will be understood that such cur
air through the ?re box or combustion cham
rent may be derived from any other suitable or
ber to expel any explosive vapors therefrom and
also cools the thermostat-electrode, as prerequi 20 convenient source.
The lines 8 and 9 are connected with an electric
sites, before the supply and‘ignition of fuel can
motor H which is placed in operation whenever
take place. In this'connection, the push rod is
the main switch It is closed. The motor H is
made hollow and provided with a plurality of
preferably arranged to simultaneously drive a
apertures which conduct -a stream of air-to the
blower l2 and a fuel pump l3, a belt l4 being
inner surface of the thermostat-electrode;to-assist
employed for this purpose. The blower I2 is
in cooling the inner surface of'the same. In-prac
arranged to deliver air to a burner air-intake
tice, in a particular steam generating unit, the
chamber [5, which may be plain or of the volute
fire box or combustion chamber can be cooled
or spiral ?ow type, and the fuel pump 13 is ar
it
through a. conduit I1 under the control of an
stat-electrode, will be substantially completely
electrically operated valve, such as a solenoid
contracted to a condition comparable ‘to that
actuated valve l8, as will be explained more fully
which it is in at a cold start. Once the thermo
hereinafter. A conduit I9 connects the fuel
stat has been cooled, or where the furnace is
pump 13 with a suitable source of supply.
35
started from 'a cold condition, only about six
down in about 45 seconds from a red hot condi
tion to a cool condition such that the thermo
seconds’ time is required for the spark to heat
and actuate the thermostat-electrode. When the
furnace is started from a cold condition, this six
30 ranged to supply fuel to a burner nozzle
In the event that the present control system is
used with a gas burner, it will be apparent that
the fuel pump l3 may be omitted and the valve
l8 utilized to control the supply of fuel to the
seconds’ delay provides ample time for the blower
burner.
to scavenge the ?re box or combustion chamber 40
Anelectrode 29 is disposed in the chamber l5
of any combustible gases that may haveremained
adjacent to the burner nozzle H3. The electrode
therein. At the same time, the cooling effect on
20 is connected by a high tension cable 2| with
the thermostat-electrode is insufficient to prevent
the secondary coil 222L of a conventional ignition
said electrode from being heated by the spark, 45 transformer 22. The coil 22a is grounded, as in
once the spark has been initiated.
dicated at 23. A second electrode 24, in the form
One of the important safety features of the
of a bi-metallic strip or thermostat element, is
present control system is a holding circuit which
disposed in spaced cooperating relation with the
electrode 26 and is generally U-shaped. One leg
spark is provided during the entire period of
25 of the thermostat-electrode 24 is suitably ?xed
operation of the burner, notwithstanding that 50 adjacent the burner nozzle Hi and is grounded as
indicated at 26. A double-pole relay switch 2‘!
the ignition switch is caused to “break” ‘after the
is provided for controlling the ignition and sup
fuel has been ignited. This ignition switch re
maintains the relay closed so that an ignition
mains broken or open until the thermostat elec
trode cools, and is so associated with the relay
ply of fuel in conjunction with an ignition con
trol mercury switch 28 and a fuel-control mer
cury switch‘ZS. Current is carried from the'line
that said relay cannot be energized to restore the
9 to the relay switch 21 through a conductor _30.
spark unless said ignition switch has ?rst been
A conductor '3l connects the conductor 3il'with
allowed to “make.”
a contact R of the relay 21. Current from the
Other objects and features of the invention will
be apparent from the following description taken 60 line 8 is carried by a conductor 32 to one end of
the primary coil 22b of the ignition transformer
in connection with the accompanying drawing in
22. The opposite end of said primary coil is con
which:
Fig. 1 is a diagrammatic View of a control sys
tem embodying the principles of the present
' invention;
nected by a conductor 33 with a contact R.’ of
the relay switch 21, which cooperates with the
contact R.
The ignition switch 28 is, for the purposes of
Fig. 2 is an enlarged detail view of the means
the present invention, pivotally mounted, as in
associated with the thermostat-electrode for
dicated at 35. This switch is arranged so that
varying the relative time of actuation of the
when the burner is cold it is “made,” or, in other
ignition switch and the fuel control switch;
Fig. 3 is a fragment of a system like that shown 70 words, the mercury in the switch completes a cir
cuit between its two contacts 36 and 31. The con
in Fig. 1 but including a switch responsive to the
tact 36 is connected by a conductor v33 with'a con
pressure in the fuel line and arranged so as to out
tact P of the relay 2‘! and with the relay coil itself.
on current to the system in event'of fuel failure;
On the other hand, the contact 31 is connected by
and
‘a- conductor '39~with a contact ‘P’ 'ofthe relay
Fig. 4 showsafragment of a modi?ed circuit
2,405,807
5
21, and by a conductor 39' with the conductor 32
going from the line 8 to one end of the primary
coil 22b of the ignition transformer 22.
The fuel control switch 29 is similar to the ig
nition switch 28 and is pivoted at A!) but is ar
ranged so that it is open when the bi-metallic
electrode .25 is in the cool condition. Thatis to
say, the mercury in the switch 29 is at the end re
* mote from contacts 4H and 42. The contact 4| is
6
‘e?ec't opening of said valve and permit fuel‘ to be!
pumped to the burner nozzle H5.
The relative timing of the operation of the ig
nition switch 28 and the fuel control switch 25
may be varied by adjusting the tension of the
springs 63 and 66 through the nuts 62 and 65, re~
spectively. Preferably these switches are so
timed that the ignition switch 28 opens or
“breaks” before the fuel switch 29 closes or
connected by a conductor 23 with the conductor 10 “makes.” Opening of the ignition switch 28 does
39 and the contact 42 is connected by a conductor
not interrupt the spark because the relay 2'!
44 to one side of a signal lamp 45 and to one ter
maintains the ignition circuit, as will be explained
minal ‘it of the solenoid-operated fuel flow con
more fully hereinafter.
trol valve :8. The other terminal 21 of the sole
After the burner has been out off by either
noid Valve l 8 is connected by a conductor 48 with 15 manual or automatic opening of the main switch
theopposite side of the signal lamp 45 and with
the conductor 33 going to the contact R’ of the
relay 27.
'
It, the thermostat-electrode 24 will begin to cool
and contract permitting the spring 56 to return
the push rod 49 and slidable block 52 to their
The ignition switch 28 and the fuel control
initial position. Any suitable means, such as
switch 29 are actuated through a hollow push rod 20 spring or counterweights (not shown) may be
49 associated with the free leg 55 of the bi-metal
provided to effect the return of the mercury
lic electrode 24. One end 5| of the rod 49 is en
‘switches 28 and 29 to their original positions of
gaged with the leg 58 of the thermostat and the
“make” and “break,” respectively.
opposite end of said hollow rod is received in a
The positioning of the thermostat-electrode 24
block 52 slidably mounted upon a base 53. The
25 in relation to the air stream introduced by the
rod 139 extends through a support 54 secured to the
blower i2 and with respect to the combustion
base 53 and carries a nut 55. A light compression
chamber we is quite important inasmuch as this
spring 56 is mounted upon the rod 49 between the
element must be so placed and shielded that the
support 54 and the nut 55 and continuously tends
incoming air is incapable of preventing said ther
to urge the rod 139 toward the right into engage
mostat-electrode from being heated by the spark
ment with the leg 55 of the bi-metallic electrode 30 to actuate the ignition switch 28 and the fuel ?ow
or thermostat 24. The pressure exerted by the
control switch 29.
.
spring 56 can be varied by suitable adjustment of
In accordance with the present construction,
the nut 55 to vary the travel of the slidable block
the upper portion of the bimetallic electrode 24
52.
35 is exposed to some extent to the incoming air
The block 52 slidably receives one end 5? of a
and to the heat re?ected from the combustion
rod 58 adapted to effect actuation of the ignition
chamber 1 5“. However, the electrode 24' is other-'
switch 28 to “break” or open the same before the
wise protected from incoming cool air by a shield
burner has been ignited, the spark circuit being
‘in which prevents the incoming air from directly
maintained after initiation through the switch 28 40 acting upon the inner surface thereof. However,
by the relay 2?, as will be pointed out later.
in order to control the cooling action of the ther
The rod 58 has a squared end 59 abutting a rod
mostat-electrode 24, as when it is desired to start
60 operatively associated with an arm 6| which
the furnace when in a hot condition, the hollow
may form a part of the cradle for the ignition
push rod 49 is provided with apertures or holes
switch 23. The rod 58 is threaded and carries 45 ‘H which communicate with the air-intake cham
an adjusting nut 62 and a spring 63 is mounted
ber l5. These holes face the oncoming air stream
on said rod between the adjusting nut 62 and the
and serve to conduct a portion of said air to the
end 5?, whereby the tension of the spring 63 may
underside of the lei-metallic electrode 215 to there
by cool the same.
be varied to alter the time of cutout of the igni
tion switch .28. It will be apparent from the fore 50
In an operative embodiment of the invention
going that expansion of the thermostat-electrode
the thermostat-electrode is completely heated
24, or, in other words, a movement of the thermo
from a cold start in about six seconds, and cooled
stat leg 59 toward the left, as viewed in Fig. 1,
down from a red hot ?re box condition in about
will exert a force upon the push rod 49 tending to
45 seconds. These time periods will, of course,
slide the block 52 toward the left. The block 52 55 vary with the size of the apparatus, the relative I
amount of fuel burned, etc. The timing is also
in turn tends to move the rod 58 along with it
through the intermediary of the spring 63. Move
affected by the distance of the re?ecting walls of
the ?re box from the burner nozzle, etc.
ment of the rod 58 in turn effects corresponding
The operation of the device is as follows:
movement of the rod 61] with the result that the
Assuming that the furnace is in a cold condi
ignition switch 28 is tilted on its pivot 35 to break 60
tion, the thermostat-electrode 24 will be con
the circuit through this switch to the ignition
tracted so that it preferably exerts no force
transformer 22.
whatever upon either the ignition switch 28 or
The fuel control switch 29 is similarly actu
the fuel control switch 29 through the push rod
ated by the slide 52 through a rod 64 carrying an
49. Hence, the ignition switch 28 remains closed
adjustable nut 65 and a tensioning spring 66.
and the fuel flow control switch 29 remains
The rod 64 abuts one end of a rod 67 associated
open. So long as the main switch I 0 is open,v
with an arm 58 which may form a part of the
the relay 2‘! is de-energized and all of the con
cradle carrying the fuel control switch 29. As has
been previously indicated, the fuel switch 29 is 70 tacts thereof are open. However, when the main
switch If! is closed, either manually or automat
arranged so that it is normally open but closes
ically,
the motor ll starts driving the blower I2
upon actuation or tilting. It will be apparent that
and the oil pump I3. Air is blown into and
movement of the block 52 will effect the desired
through the air chamber 15 and the combustion
tilting of the fuel control switch 29 so that the cir
cuit to the solenoid valve I5 will be completed to 75 chamber 152, but no fuel is delivered to the burn
er nozzle 16 because the solenoid valve I8 is now
2,405,801?
7
8'
so as to by-pass fuel to avoid building up exces
sive pressure in the pump or line, [1 until such
time as the solenoid valve 18 is opened.
When themain switch 10 is closed, the ignition
switch 28 already being closed, the relay 21 is en
ergized by a circuit which may be traced from
the line 8 through conductors 32, 39' and 39,
across contacts 36 and 31 of the ignition switch
28, conductor 33, relay 21 and conductor 30 to
the other side of the line 9. This energization of
the relay 21 closes the contacts P and P’ to com
plete a holding circuit for the relay which can be
traced from the line 8 through conductors 32, 39’
and 39 to the contacts P’ and P, through conduc
tor 38 to the relay 21, and from the relay 21
through conductor 33 back to the line 9. In
other words, the contacts P and P’ are in paral
lel with the ignition switch 28 and subsequent
opening of said ignition switch upon spark-heat
ing and expansion of the thermostat-electrode
24 will not tie-energize the relay 21.
Energization of the relay 21 also closes the
contacts R. and R’ to complete a circuit through
the primary coil 22b of the ignition transformer
22. ‘The primary circuit for the ignition trans
former 22 may be traced from the line 8 through
the conductor 32, the primary coil 22*‘, conduc
tor 33 to the contact R.’ and from the contact R
through the conductors 31 and 33 back to the
V
to the solenoid valve 18 also completes the oil‘
cuit to the signal lamp 45 which is then illumi
nated to indicate that fuel is being supplied to
the burner nozzle it.
When the main switch I0 is opened, either
manually or automatically, to shut down the
burner, current to the motor H, which operates
the blower I2 and the fuel pump i3, is interrupt
ed and their operation ceases. However, suffi
cient heat normally remains in the combustion
chamber .to keep the thermostat-electrode 24 in
expanded condition for a short period of time
and this prevents the ignition switch 28 from
tilting back to its original position to “make"
closed. The fuel pump I3 is preferably arranged
15 a circuit across the contacts 36 and 31.
It is
during this time of high temperature that fuel
discharged into the combustion chamber is most
hazardous.
It will also be apparent that upon openingof
20 the main switch 13, either manually or auto
matically, the relay 21 is deenergized and this
relay cannot be re-energized until the ignition
control switchi28 is permitted to close by cooling
and contraction of the thermostat-electrode 24.
25 Thus,~with the switches 10 and 28 open and with
the ‘thermostat-electrode 24 in a hot condition,
it is impossible to complete the ignition circuit
and ‘it is also impossible to inject fuel into the
hotlchamber i5BL through the injector nozzle l6,
30 because the relay 21 cannot be energized so long
as the ignition switch 28 is open.
other side of the line 9. The secondary circuit ‘
of the ignition transfer 22 can be traced from
Should the
main switch l0 beiclosed at this time, the circuit
to the motor I i will be completed and the blower
the ground connection 23 through the secondary
i2 and fuel pump 13 will ‘be started. Fuel will
coil 22*‘ of the ignition transformer 22, conduc
tor 2i, electrode 20, the thermostat-electrode 24 35 be by-passed in the pump 13 without reaching
the burner nozzle l6 and the blower12 will blow
to the ground connection 26, whereby an igni
airithrough the air chamber l5and combustion
tion spark is established between the plain elec
chamber 15*’ to cool the same and remove any
trode 29 and the thermostat-electrode 24. In
explosive mixtures that may remain therein.
asmuch as the fuel switch 29 is open at this time,
Simultaneously, the incoming air will pass
the solenoid valve I8 is not energized and there
through the holes H in the push rod 49 to aid
fore remains closed. The ignition spark between
inoeffecting cooling of the thermostat-electrode
the electrode 26 and the thermostat-electrode
24 toatmospheric temperature. The contraction
24 heats said thermostat-electrode and causes it
of the thermostat-electrode 24 will relieve the
to expand. When the thermostat-electrode 24
reaches a predetermined temperature it will have 45 force acting upon the push rod 49 and thus per
mit the fuel control switch 29 to “break.” There
expanded sufficiently to actuate the ignition
after, and upon further cooling of the thermo
switch'28 to break the circuit at the contacts 36
stat-electrode 24, the ignition control switch 28
and 31, actuation of said ignition switch being
effected through the push rod 49, block 52, spring
.63 and rods>53 and 60. This does not interrupt
the spark because the ignition circuit is now
maintained by the holding circuit previously de
scribed. ‘Further expansion of the thermostat
electrode 24 will actuate the fuel control switch
29 through the push rod 49, spring '66, and rods
34 and 161 to effect closing of this switch and
completion of the circuit to the solenoid valve
18, which circuit can be traced as follows: From
so
will be permitted to “make” and energize the
relay 21 and complete theignition circuit. The
spark produced thereby, of course, will again heat
the thermostat-electrode 24, which again auto
matically causes the ignition switch 28 to open
or “break” and the fuel control switch 28 to close
or “make” and operate the solenoidevalve l3 con
trolling the supply of fuel to the burner nozzle
it. If the spark fails or is of insui?cient intensity
to ignite the fuel, it will be insu?‘icient to actuate
the thermostat-electrode 24 so that no fuel will
the contacts 4! and 42 of the fuel control switch 60 be supplied to the burner, as has been previously
explained.
‘29, conductor 44 to one terminal 46 of the sole
Figure 3 illustrates a portion of a system such
noid valve 18 and from the other terminal 41 of
as shown in Figure l, modifying the same by the
said solenoid valve through conductors Miami
addition of a conventional pressure responsive
33, through contacts R’ and 7R of the relay 21
switch
‘P2 in the fuel line I1 between the pump
65
and through conductors 3| and 30 back to the
13 and the solenoid valve I78. The switch P2 is
other side of the line 9. Completion of this cir
line 8 through conductors 32, ‘39', 39, 43, across
cuit effects opening of the solenoid valve l8 and
allows the fuel pump l3 to supply oil to the burn
er'nozzle 16. As has been previously stated, if
the spark between the electrodes 29 and 24 fails
altogether, or fails to reach a predetermined in
tensity ‘or temperature sufficient to ignite the
fuel,- the fuel switch 29 will not be actuated and
the-circuitto the solenoid valve 18 will not be
completed. However, completion of the circuit
arranged to complete the circuit through the
conductors 3i! and 32 so long as a predetermined
pressure exists in the line 11. Opening of the
solenoid fuel control valve ill, of course, does not
relieve the pressure on the switch P2 so as to
permit the same to open because the burner noz
zle' I5 maintains a sufficiently high back pressure
to keep said switch closed while the burner is in
operation.
2,405,807
The switch P2 adds a further safety feature
to the invention in that should there be a mo
mentary lack of fuel in the line I? or should the
supply of fuel become exhausted, the current to
the system normally ?owing through the con
ductors 3G and 32 will be discontinued.
The
valve IE will then automatically close, the spark
between the electrodes 20 and 34 will beinter
10
contacts R’ and R of relay 2'! and conductors 3i
and 30 to the other side of the line 9. Upon
opening of the main switch in to de-energize the
relay 2? ignition cannot be reestablished until
the thermostat-electrode 24 has cooled ‘suffi
ciently to ?rst open the fuel control switch 23
and then close the ignition switch 28. When this
has occurred the operation is the same as de
rupted, the signal lamp 45 will go out, etc.
scribed with respect to Figure 1 untilicontinued
If the fuel failure is only momentary, and 10 heating
of the thermostat-electrode 24 due to a
pressure in the fuel line is quickly built up, nev
flame heat causes opening of the ignition switch
ertheless the resumption of the operation of the
28 to discontinue the ignition.
burner will be the same as from a cold-start con
While the switches 28 and 29 have been de
dition. That is to say, although the circuit is
scribed as mercury switches it is to be understood
again completed by the switch P2 through the 15 that
the invention contemplates the use of snap
conductors 30 and 32, no fuel can be supplied to
action switches, micro-switches, or any other
the nozzle I6 unless the spark at the electrodes
switches capable of functioning in the system to
20 and 24 is of su?icient intensity to assure igni
accomplish the objectives of the invention.
tion of the fuel. The system then operates in
It will be understood that various other
the manner aforedescribed.
changes may be made in the control system dis
When the system including the pressure re 20
closed herein. For example, a time delay switch
sponsive switch P2 is put out of ‘operation auto
may
be used in place of the relay switch and this
matically or manually by opening of the main
would insure a definite time after the blower
switch iii, su?icient pressure will be maintained
has been turned on, or the main switch closed,
in the line H to keep its contacts closed so that
25 before the fuel could be supplied to the burner.
the electrical connection itself across the con
Again, a motor driving the fuel pump could be
ductors 3B and 32 is not interrupted, although no
substituted in place of the solenoid valve, or this
current reaches these conductors at that time
motor could also drive the blower and could be
due to opening of the switch iii. Hence, when
started through the same circuit that actuates
the main switch It‘! is » again closed the current
to the system is completed and no delay occurs 30 the solenoid valve.
in the starting up of the burner.
The latter arrangement, of
course, would have the distinct disadvantage of
'
increasing the cooling down time and eliminating
It will be clear from the foregoing that the
the free blower time to expel combustible gases
present control system provides for a maximum
that may have accumulated in the combustion
of safety in that it absolutely prevents initiation 35 chamber.
of the supply of fuel to the burner nozzle at such
It will also be understood that while the ig
times as would present a danger from ?re or
nition switch 28 and the fuel control switch 29
have been described as actuated upon expansion
explosion. A11 danger from restarts is avoided
by providing for a predetermined time delay and
of the thermostat electrode 24, these switches
cooling before ignition can again occur, such
40 can obviously be arranged for actuation upon
gases as may have remained in the combustion
icontractive
movement of the thermostat-elec
rode.
chamber being scavenged during this cooling
period so that when ignition does occur it pre
It is conceivable that still further speci?c
cedes the introduction of fresh fuel into the fire
changes
may be made in the system without de
box or combustion chamber and the spark must 45
parting from the spirit of the invention or the
be of such intensity as to be capable of igniting
scope of the appended claims.
I claim:
1. A fuel burner control system comprising: a
burner; valve means for controlling the ?ow of
the fuel before such fuel can be introduced.
In the system above described the spark is
maintained throughout the operating period of
the burner, but if desired the system can be modi 50
fuel to said burner; continuously operating means
?ed to discontinue the ignition after a flame has
for supplying air to said burner and for supplying
been established in the ?re box 15%. This may
fuel under pressure to said valve means; means
be accomplished by adjusting the relative com
for igniting said fuel, said igniting means com
pression of the springs 63 and 86 associated with
the switches 28 and 25! so that the ignition con 55 prising an ignition circuit including a source of
high voltage current and a pair of spaced current
trol switch 28 is opened by heating of the thermo
conducting electrodes, one of said electrodes be
stat-electrode 25.4 by the heat of the burning fuel
due to heating of the thermostat-electrode 2G by
ing connected to said source of high voltage cur
rent and the other of said electrodes being
upon cooling of the thermostat-electrode 24, the
produced between said electrodes; and means
after the fuel control switch 29 has been closed
the ignition spark. Further, a suitable lost mo 60 grounded and being thermally reactive to change
its shape in response to the heat of the spark
tion connection (not shown) is provided so that
controlled by said thermally responsive electrode
ignition switch 28 is closed after the fuel control
switch 29 has been opened. The circuit must be
slightly altered by‘connecting the primary coil
22b of the ignition transformer 22, as shown in
Figure 3, so that the ignition spark is discon
tinued whenever the ignition switch 28 is open.
Thus, the primary coil 22]“ of the ignition trans
former 22 is placed in series with the ignition
control switch 28, the circuit being traced from
line 8, Figure 1, through conductors 32, 33' and
39, across contacts 35-3’! of the ignition switch
28, conductor 38, and conductor "f2 (Figure 3)
to the primary coil 22b, conductor 33 (Figure 1),
65
operable to cause said fuel flow controlling valve
means to permit a ?ow of fuel to said burner
only when said thermally responsive electrode is
expanded by the heat of a spark of sufficient in
tensity to ignite said fuel.
2. A fuel burner control system comprising: a
burner; a fuel pump; a circuit including electri
cally operated valve means for controlling the
?ow of fuel from said pump to said burner;
means for igniting said fuel, said igniting means
including an ignition circuit having a ‘pair of
spaced current conducting electrodes connected
therein, one of said electrodes being bimetallic
2,405,807
11
and adapted to change its shape in response. to
the heat of the spark produced between said
electrodes; a motor for driving said fuel pump
connected to be driven simultaneously with the
12
6. A burner control system comprising; a
burner; a circuit including electrically operated
means for supplying fuel to said burner; fuel
ignition means including an ignition circuit hav
ing an ignition switch and a pair of current con
initiation of the spark; and a switch in the cir
ducting electrodes connected therein positioned
cuit of said flow controlling valve means actuable
adjacent said burner, one of said electrodes com
to its closed position by said bi-metallic elec
prising a bi-metallic strip; means operable upon
trode to effect opening of said valve means when
expansion of said bi-metallic strip as the result
said bi-metallic electrode is subjected tov the heat
of a spark of sufficient intensity to ignite said 10 of spark-heating thereof for actuating an ignition
control switch and a fuel control switch; and an
fuel.
ignition switch in said ignition circuit and a fuel
3. A fuel burner control system comprising: a
control switch in said ?rst-mentioned circuit ar
burner; a fuel control circuit including an elec
ranged to be actuated by said last-mentioned
tromagnetic valve for controlling the ?ow of fuel
to said burner; continuously operating means for 15 means, said ignition switch being closed and said
fuel switch being open when said bi-metallic strip
supplying air to said burner and for supplying
is cool.
fuel under pressure to said electromagnetic
7. A burner control system comprising: a
valve; means for igniting said fuel, said igniting
burner; a circuit including electrically operated
means comprising an ignition circuit including a
source, of high voltage current and a pair of 20. means for supplying fuel to said burner; fuel
ignition means including an ignition circuit hav
spaced current conducting electrodes connected
ing a pair of current conducting electrodes con
in said circuit, one of said electrodes. being bi
nected therein and positioned adjacent said
metallic and adapted to change its shape in re
burner, one of said electrodes comprising a bi
sponse to the heat of the spark produced between
said electrodes; and a switch in said fuel circuit 25. metallic strip; means operatively engaged with
said ‘bi-metallic strip and arranged for actuation
controlled by said heat responsive electrode op
by expansion and contraction of said bi-"netallic
erable to e?ect opening of said electromagnetic
strip; and an ignition switch in said ignition cir
valve to permit a flow of fuel to said burner when
cuit and a fuel control switch in said ?rst-men
said heat responsive electrode is subjected to the
tioned circuit arranged to be actuated by said
heat of a spark of su?icient intensity to ignite
last-mentioned means, said ignition switch being
said fuel.
closed and said fuel switch being open- when said
‘i. A fuel burner control system comprising: a
bi-metallic strip is cool, said ignition switch and
burner; a fuel supply control circuit including
fuel switch being further arranged so that upon
means for controlling the supply of fuel to said
expansion of said lei-metallic strip as a result of
burner; means for igniting said fuel, said ignit
spark-heating thereof said ignition switch is
ing means comprising, an ignition circuit includ
opened before said fuel switch is closed.
ing an ignition transformer, and a pair of spaced
8. A burner control system comprising: a
current conducting electrodes connected in said
burner; a circuit including electrically operated
circuit positioned adjacent said burner, one of
said electrodes being thermally reactive to change 40 means forsupplying fuel to said burner; fuel
ignition means including an ignition circuit and
its shape in response to the heat of the spark
a pair of electrodes connected in said circuit and
produced between said electrodes; and means
positioned adjacent said burner nozzle, one of
including a pair of switches actuable by said
said electrodes comprising a b-i-metallic strip;
thermally responsive electrode solely as a result
means operatively engaged with said bi- i etallic
of spark-heating thereof,>one of said switches
strip and arranged for actuation by expansion of
being arranged in saidfuel. supply control circuit
said ‘pi-metallic strip; and an ignition switch
to complete the circuit to said fuel flow control
connected in said ignition circuit and a fuel con
means to permit fuel to flow to said burner when
trol switch connected in said first-mentioned
said “thermally responsive electrode is subjected
circuit arranged to be actuated by said last-men
to the heat of a spark of sufficient intensity to
tioned means, said ignition switch being closed
ignite said fuel, and the other of said switches
and said fuel switch being open when said bi
being connected in circuit with said electrodes
metallic strip is cool, and said ignition switch and
and being arranged so that it must be closed at
fuel switch being arranged so that said fuel switch
the start of ignition and to open after said. fuel,
55. is closed before said ignition switch is opened
has been ignited.
when said bi-metallic strip is heated by a spark
5. A fuel burner control system comprising:
of sufficient intensity to ignite said fuel.
a burner; a circuit including, a main switch; a
9. A burner control system comprising: a
motor in said circuit; a blower, said motor being
burner; an ignition circuit including a pair of
connected to drive said blower immediately upon
closing of said main switch; a fuel circuit in 60 electrodes positioned adjacent said burner, one
of said electrodes being bi-metallic; continuously
cluding electrically operated means for control
operating means for supplying air to said burner;
ling the supply of fuel to said burner; means for
a continuousiy driven fuel pump for supplying
igniting said fuel including an ignition circuit
fuel to said burner nozzle; a conduit connecting
connected to be completed upon closing of said
said fuel pump with said burner; a fuel circuit
main switch and having a pair of spaced current
having a solenoid valve connected therein and
conducting electrodes connected therein, one of
arranged in said conduit for controlling the sup
said electrodes being thermally reactive and in,
ply of fuel to said burner; means operatively
cluding a portion movable as a result of being
associated with said bi-metallic electrode and ar
heated by the spark produced between said elec
ranged to be actuated upon expansion of said =bi
trodes; and a fuel control switch in the circuit
metallic electrode; and a fuel control switch con
of said electrically operated means arranged to
nected in said fuel circuit arranged to be actuated
be closed upon movement of said movable portion
by said last-mentioned means to effect opening
of said one electrode when said one electrode is
of said valve upon actuation of the ignition bi
subjected to the heat of a spark of sufficient in
75 metallic electrode when said spark between said
tensity to ignite said fuel.
2,405,807
13‘
electrodes is of an intensity sufficient to ignite
the fuel.
'
10. A furnace and control system therefor com
prising: an air inlet chamber; means for causing
an air stream to ?ow through said air inlet cham
ber: a burner in said air inlet chamber: ignition
14v
said burner, one of said electrodes being thermally
responsive; means in said ignition circuit for pro
ducing a spark at said electrodes; a fuel pump
for supplying fuel to said burner nozzle; a con
duit connecting said fuel pump with said burner;
_ a solenoid valve in said conduit for controllingthe
means including a bl-metallic electrode having
supply of fuel to said burner; means operatively
inner and outer surfaces positioned adjacent said
associated with said thermally responsive elec
burner; means shielding the inner surface of said
trode arranged to be actuated upon expansion of
lei-metallic electrode from the incoming air 10 said thermally responsive electrode; means com
stream; a tube operatively associated with said
prising a fuel control circuit including a switch
bi-metallic electrode, said tube having one end
arranged to effect opening of said solenoid valve
thereof terminating adjacent the inner surface of
upon actuation of said aforementioned means by
said 'bi-metallic element and having a plurality
said thermally responsive electrode when said
of apertures extending through the wall thereof, 15 spark between said electrodes is of an intensity
said apertures being arranged in the path of the
su?icient to ignite the fuel; and a pressure re—
oncoming air stream so as to admit air into said
sponsive switch in said fuel conduit between said
tube for discharge through said one end of said
fuel pump and said solenoid valve connected with
tube adjacent the inner surface of said bi-metallic
said ignition and fuel control circuits arranged to
electrode to eifect cooling of said inner surface.
interrupt the flow of current to said ignition and
11. A safety control system for fuel burners
fuel control circuits upon a predetermined pres
comprising: a, burner; a circuit including electri
sure drop in said fuel conduit.
cally operated means for supplying fuel to said
14. A furnace and control system therefor com
burner; ignition means including an ignition cir
prising: an air inlet chamber; a blower arranged
cuit having a pair of electrodes connected therein
to introduce air into said air inlet chamber; a
and arranged adjacent said burner for igniting
main switch controlling said blower; a burner in
said fuel: a relay and an ignition switch con
said air inlet chamber; a fuel switch; an ignition
nected in circuit with said ignition means. said
switch; a pair of electrodes positioned adjacent
relay being arranged in the circuit so that one
said burner. one of said electrodes being ther
pair of its contacts is in parallel with the con 30 mally actuatable to control said fuel and ignition
facts of said ignition switch; a solenoid valve in
switches in a given order; and means arranged
said first-mentioned circuit for controlling the
to divert a portion of said incoming air to cool
supply of fuel to said burner; and a fuel control
said thermally actuatable electrode, whereby if
switch in said ?rst-mentioned circuit arranged
said main switch is closed at the time of fuel fail
to control said solenoid valve; actuating means 35 ure. said thermally actuatable electrode will be
for said ignition switch and fuel control switch
cooled and effect an opening of said fuel switch
arranged so that upon the formation of spark
and closing of said ignition switch to condition
of predetermined intensity between said elec
the system for a restart.
trodes said fuel control switch will be closed. to
15. A furnace and control system therefor com
complete the circuit to said solenoid valve, and 40 prising: an air inlet chamber; means for forcing
said ignition control switch will be opened.
- air into said air inlet chamber; a burner in said
12. Fuel burning apparatus comprising: a fur
air inlet chamber; spark ignition means including
nace having an air-intake vchamber and a ?re
a thermally responsive electrode heated by said
box or combustion chamber above said air-intake
spark and positioned adjacent said burner; burner
chamber; a circuit including an electrically oper
control means operable in accordance with the
ated blower for introducing air into said cham
thermal condition of said thermally responsive
berfa burner in said air-intake chamber; a con
electrode; means shielding said thermally respon
duit for supplying fuel to said burner; a fuel con
sive electrode from direct contact with said in
trol circuit including an electrically controlled
coming air; and means for diverting a portion of
fuel valve connected in said conduit; an ignition
said air to effect cooling of said electrode.
’
circuit having a pair of electrodes connected
16. A furnace and control system therefor of
therein and arranged adjacent said burner, said
the type described in claim 15, in which the means
ignition circuit including a relay, an ignition
transformer
an ignition switch, said. ignition
switch being connected in parallel with one pair
of contacts of said relay; a fuel control switch in‘
said fuel control circuit for controlling the opera
tion of said electrically operated fuel valve; a
main switch for controlling the supply of current
for diverting a portion of the incoming air to
cool the thermally responsive electrode comprises
a tube having an open end terminating adjacent
said thermally responsive electrode and having a
plurality of apertures extending through the wall
thereof; said apertures being arranged in the path
of the incoming air so as to admit air into said
to said blower, ignition and fuel circuits, said 60 tube for discharge through said open end adja
ignition switch being closed when said burner is
cent said thermally responsive electrode to effect
in cold condition and said fuel control switch be
cooling of said electrode.
"
ing open when said burner is in cold condition,
17. A burner control system comprising: av
said ignition switch and fuel control switch being
burner; a fuel control circuit including electri
arranged to be operated in succession in response
cally operated means for controlling the ?ow of
to the formation of a spark of predetermined in
fuel to said burner; an ignition circuit including
tensity between said electrodes; and means oper
means for continuously igniting said fuel, said
ated in accordance with the intensity of said spark
igniting means including a pair of spaced current
arranged to ?rst close said fuel control switch to
conducting electrodes, one of said electrodes be
effect opening of said electrically controlled 70 ing thermally responsive to the heat produced by
valve to supply fuel to the burner and to there
the spark between said electrodes; an ignition
after open said ignition control switch.
switch arranged to be opened by said thermally
13. A burner control system comprising: a
responsive electrode solely as the result of spark
burner; an ignition circuit having a pair of elec
heating of said electrode; and a fuel control
trodes connected therein and positioned adjacent
switch in the circuit of the electrically operated
2,405,807
15"
flow controlling means, means arranged to close
and maintain said fuel control switch in closed
position by the thermal reaction of said thermally
responsive electrode only when said thermally
responsive electrode is subjected to the heat of a
spark. of sunicient intensity to ignite said fuel.
18. A burner control system, comprising: a‘
burner; means for supplying fuel to said burner;
an ignition circuit comprising means for normally
igniting said fuel including a thermally respon ll)
sive electrode and an ignition switch in said igni
tion circuit, said ignition switch being actuatable
by said thermally responsive electrode, said ther
mally responsive electrode being arranged to
maintain said switch open to prevent the initia
tion of a spark when the ?rst-named means is
out of operation and said thermally responsive
electrode is still in a heated condition; and means
ing a'pair of current conducting electrodes connected to produce a continuous spark adjacent
said burner; an electric motor drivingly con
nected with said blower, said electric motor being
connected in circuit with said ignition means so
that it is placed in operation to effect scavenging
of said fire box simultaneously with the initiation
of said spark; and means controlled by one of'
said electrodes for initiating and maintaining a
supply of fuel to- said burner upon spark-heat
ing of said one electrode to a predetermined
temperature;
23. A fuel burner control system, comprising:
a burner; a, fuel supply circuit including elec
trically operated means for controlling the ?ow
of fuel to said burner; means for igniting said
fuel, said igniting means including ignition cir
cuit means having a pair of spaced current con
ducting electrodes connected therein to maintain
including a normally continuously operating
motor driven blower arranged to quickly cool said 20 a continuous spark therebetween, one of said
electrodes being a bi-metallio thermostat element
thermally responsive electrode to atmospheric
and being adapted tochange its shape as a result
temperature to permit said ignition switch to
of the heat produced by the spark between said
close and complete the ignition circuit, whereby
to condition the apparatus for automatic re
initiation of a spark.
19. A burner control system, comprising: a
burner; means for supplying fuel to said burner;
and means for spark-igniting said fuel including
circuit means having an ignition switch and a
pair of current conducting electrodes spaced
apart and connected to normally maintain a con
tinuous spark therebetween, one of said electrodes
being bi-metallic and arranged to control said
ignition switch to prevent the initiation of a spark
when the burner is out of operation and said bi
metallic electrode is still in a heated condition.
20. A burner control system, comprising: a
burner; means including a switch for controlling
the supply of fuel to said burner; and means for
igniting said fuel including a circuit having an
ignition switch and a pair of current conducting
electrodes connected to produce a continuous
spark between said electrodes at a point adjacent
said burner, one of said electrodes being bi
metallic and adapted to change its shape in re
sponse to heating by said spark and being ar
electrodes; and a fuel control switch in the cir
cuit of said electrically operated ?ow controlling
means, said fuel control switch being arranged
to be actuated to closed position by the change
in shape of said bi-metallic thermostat element
to allow fuel to be supplied‘ to said burner only
when said bi-metallic thermostat element is sub-_
jected to the heat of a spark of suf?cient intensity
to ignite said fuel. '
24. A safety control system for fuel burners,
comprising: a burner; means for supplying fuel
to said burner; current conducting ignition elec
trodes adjacent said burner for igniting said fuel,
one of said electrodes being bi-metallic and posi
tioned relative to- said burner so as to change its
shape solely as a result of being heated by the
spark; an ignition circuit for- providing a spark
between said electrodes; an ignition switch in said
ignition circuit; a fuel circuit including a fuel
control switch for controlling said fuel supply
means; and means actuatable in response to said
change in shape of said bi-metallic electrode for
actuating said ignition and fuel switches in suc
cession and upon heating of said one electrode
ranged to control the switch of said fuel supply
control means and said ignition switch to prevent
to a predetermined temperature solely by said
the initiation of a spark and a subsequent supply
of fuel to said burner when the burner is shut
down and the bi-metallic electrode is still in a
heated condition.
25. A burner control system, comprising: a fuel
burner; an ignition circuit including a pair of
21. A control system for a fuel burner, com
prising: a burner; means for supplying fuel to
said burner; fuel ignition means including a cir
cuit having a pair of current conducting elec
trodes connected to produce a spark adjacent said
burner, one of said electrodes being bi-metallic;
an ignition switch arranged in circuit with said
spark.
current conducting electrodes arranged adjacent
said fuel burner, one of said electrodes being
thermally responsive to the heat of the spark; a
relay and a relay switch connected with said igni
tion circuit; an ignition switch connected in par
allel with said relay switch; a main switch con
trolling the supply of current to said ignition cir
cuit; a holding circuit including said relay switch
electrodes, said ignition switch being operable by 60 for maintaining said relay energized when said
main switch is closed and said ignition control
said bi-metallic electrode and being arranged so
switch is open; a fuel control circuit including an
that it is opened when said bi-metallic electrode
electrically operated valve for controlling the sup
has been expanded a predetermined amount as
ply of fuel to said burner; a fuel control switch
the result of being heated by. said spark; and
means including a normally continuously operat 65 connected in said fuel control circuit for control
ling said valve, said ignition switch and fuel con
ing motor driven blower arranged to quickly ef
trol switch being arranged» to be actuated upon
fect cooling of said lei-metallic electrode when
predetermined expansion of- said thermally re
the burner is out of operation so that said bi
sponsive electrode; and means actuated in accord-.
metallic electrode will contract and allow said
ance with the thermal expansion of said ther
70
ignition switch to close to permit a restart.
mally responsive electrode arranged to actuate at
22. Furnace control apparatus including a fire
least said fuel control switch, whereby said elec
box; a burner operatively associated with said
trically operated valve is opened when the» spark
fire box; a normally continuously operating
between said electrodes reaches a predetermined
blower arranged to introduce air into said ?re
box; ignition means including circuit means hav 75 intensity.
17
2,405,807
26. A burner control system, comprising: a
burner; means for supplying fuel to said burner;
an ignition circuit comprising means for continu
ously spark-igniting said fuel including a pair of
current conducting electrodes, one of said elec
trodes being lei-metallic and of a generally 111
verted U-shape and having one leg thereof ?xed
to a support and its other leg free to move in
accordance with the heat produced solely by said
spark, the other of said electrodes having its end 10
18
spaced a ?xed distance from the upper end of
said U-shaped bi-metallic electrode to provide a
spark gap therebetween; and an ignition switch
connected in said circuit and actuated by the
movement of said free leg of said lei-metallic elec
trode for controlling the spark, said switch being
arranged to prevent the initiation of a spark when
the burner is out of operation and said bi-metallic
electrode is still in a heated condition.
PERRY ARANT.
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