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Патент USA US2406925

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Sept. 3, 1946.
c. K. STRQBEL ‘
,
2,406,925
CONTROL AND IGNITION SYSTEM FOR FUELBURNERS
Filed. June 15 , 1945
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Patented Sept. 3, 1946
2,406,925
NiTE-D STATES PATENT OFFICE
2,406,925
CONTROL AND IGNITION SYSTEM FOR
FUEL BURNERS
Charles K. Strobel, Pittsburgh, Pa., assignor to
Robertshaw Thermostat Company, Young-wood,
Pa., a corporation of Pennsylvania
Application June 15, 1945, Serial No. 599,634
15 Claims.
(01. 15s—11'z.1)
'
1
2
This invention relates to control and ignition
systems for fuel burners and, more particularly,
to electrically operated systems therefor.
Systems of the character indicated have been
arranged with safety control devices adapted to
supplying fuel to a pilot burner 22 located ad
jacent the main burner l0. .
The electromagnetic valve I6 is preferably of
standard commercial form having an operating
coil 24 and armature 25 which are shown sepa
rated therefrom in the drawing for purposes of
clarity in illustration. As will be apparent here
inafter, the electromagnetic valve i6 may be pro
vided‘ with a manual setting device for opening
be supplied with electrical energy from a thermo
couple or thermopile during the running period.
As such energy is usually of insui?cient value to
start the system in operation, it has been pro
Posed to employ energy from a source of com
mercial supply for the starting period.
10 the valve in the event of a power failure and an
The
present invention is particularly concerned with
means to make such systems generally adapted
for space heating services where the fuel flow
automatic resetting device for superseding the
manual control when the power supply is re
sumed. As such types of manual-set, automatic
reset devices are well known to those skilled in
control device may be a standard article of com 15 the art, illustration of the details thereof has
been omitted and further description is deemed
merce and not subject'to modi?cation for the
unnecessary. As this description proceeds it will
proposed use.
.
be apparent that the coil 24 of the electromag
An object of this invention is to utilize a single
electromagnetic valve for condition and safety
netic valve 16 is assumed to be either energized
control in conjunction with a gaseous fuel burner
without requiring alteration or modi?cation in
standard forms of valves to adapt it for such
preventing flow of fuel to the main burner 10
or deenergized for the purpose of permitting or
and (that such energization is sufficient to over
come the bias of the valve IE to closed position.
The electromagnetic valve I6 is under control
Another object of the invention is to employ
thermoelectric energy independent of any out 25 of an electromagnetic device designated gener
ally by the reierence numeral 26. This device
side source for operating the safety control de
comprises a horseshoe magnet 28 having an
vice during the burner running period while
armature 30 movable between attracted and re
utilizing energy from a commercial source of sup
uses.
ply in connection with this device during the
leased positions relative to the pole faces thereof.
starting period only.
A stem 32 has lost motion connection with the
armature 30 and is reciprocable relative to the
Another object of the invention is to render
the system self-starting and recycling as long as
the main fuel and electric control devicesare
turned on.
Another object of the invention is to incorpo- 0
rate the required transformers for adjusting the
voltages to different circuit elements while utiliz
ing certain characteristics thereof for dual pur
poses where feasible.
horseshoe magnet 28 for moving the armature to
released position under bias of a coil spring 34.
The stem 32 is provided with an enlarged head
36 which is adapted to engage the armature 3B
and to move it toward the pole faces of the horse
shoe magnet 28 against the bias of the spring 34.
When the armature 30 is engaged with the pole
faces of the horseshoe magnet 28, that is, in its
attracted position, then a contact bar 31 carried
by the stem 32 is positioned thereby so that ?rst
and second switch contact pairs 38 and 46 at
opposite ends of the bar respectively are closed.
is a schematic view of a control and ignition sys
It will be understood that these contact pairs both
tern for gaseous fuel burners embodying the in 45 comprise the usual ?xed and movable contacts.
vention.
The resetting movement of the armature 30 to
Referring more particularly to the drawing, a
attracted position is under control of an electro
main burner to is supplied with fuel by a main
magnetic resetting device designated generally by
fuel pipe I‘). in which a main fuel shut-off cock
the reference numeral 42. The resetting means
i4 is provided. The ?ow of fuel in the pipe [2 is 50 comprises a magnet plunger 44 having a swivel
connection 46 depending therefrom and carrying
also under the control of an electromagnetic valve
a coil spring 48 which serves to support one end
It which is biased to closed position. Interposed
of a‘ pivoted lever 50 loosely on the connection 46.
between the main fuel cock l4 and the electro
The opposite end of the lever 50 carries a mov
magnetic valve l? is a T connection l8 having a
‘reducing outlet to accommodate a conduit '20 for 55 able contact forming one of a third pair of switch
Other objects and advantages will become ap
parent from the following description taken in
connection with the accompanying drawing which
2,406,925
3
4
contacts 52 associated with the electromagnetic
netic valve circuit (hereinafter called the ?rst cir
cuit) and has its primary coil connected by wires
84, 86 to the main switch ‘I8. The secondary coil
of the transformer 82 is connected at one end by
device 26. It will be observed that the lever 50
is spaced from the enlarged head 36 of the stem
32 when all the contact pairs 38, 4t] and 52 are
engaged. The arrangement is such that upon U! a wire 86 to one end of the electromagnetic valve
coil 26 and the opposite end thereof is connected
upward movement of the magnet plunger 44, as
will occur upon attraction thereof by means to be
described, the lever 50 will be rotated on its piv
by a wire 90 to the ?xed contact of the third con
tact pair 52. The ?rst circuit also includes the
thermostatic device 62 and the ?rst and third con
otal mounting causing the end carrying the mov
able contact of contact pair 52 to engage the en 10 tact pairs 38 and 52, respectively. The connec
tions may be traced by wire 92 from the movable
larged head 36 and reset the armature 30 in at
contact of third contact pair 52 to movable con
tracted position relative to the pole faces of the
tact of ?rst contact pair 38, wire 94 from ?xed
horseshoe magnet 28.
contact of ?rst contact pair 38 to ?xed contact
The electromagnetic device 26 is adapted to be
‘if; of the thermostatic device 62, movable contact
energized by thermoelectric means for maintain
‘ID, arm 66, movable contact 68, ?xed contact 22
ing the armature 3K! in attracted position after it
and wire 96 to the opposite end of the electro
has been reset to such position by the resetting
magnetic valve coil 24.
means 42. As shown, the thermoelectric means
The heater coil ‘I6 for the thermostatic device
comprises a thermocouple 54 exposed to the heat
of a ?ame at the pilot burner 22 and connected 20 62 is connected at one end by a wire 98 to the
bimetallic spiral 64 and at the opposite end by a
by wires 56 and 58 to a winding 60 for the horse
wire I06 to a ?xed contact I 02 which is adapted
shoe magnet 28. It will be understood that the
to be engaged by one end of the armature 25 of
electromagnetic device 26 does not receive sum
the electromagnetic valve I6. The armature 2.5
cient energy from the thermocouple 54 to attract
is permanently connected at the opposite end to
the armature 39 into engagement with the pole
the wire 96.
faces of the horseshoe magnet 28, but that the
A second circuit is connected to the source 86
resetting means 42 is relied upon for such opera
under control of the main switch ‘I8 and in par“
tion. However, after the armature 30 has been
ailel with the ?rst circuit. The second circuit
thus reset, the thermocouple 54 will generate suffi
cient energy to retain the armature 30 in at 30 includes the primary coil of a second transformer
I65 which also forms an operating coil for the
tracted position provided that the pilot burner 22
magnet plunger 44. A thermal switch, designated
is producing a ?ame.
generally by the reference numeral I68, has ?xed
The electromagnetic valve I6 is also under the
and movable contacts H0 and H2, respectively,
control of a device responsive to a condition
included in the second circuit. The thermal
caused by operation of the main burner I0. As
switch I68 is preferably of the bimetallic snap
disclosed in this embodiment, this condition re
switch type and includes a bimetallic element I I4
sponsive device is designated generally by the ref
which serves to operate the movable contact II2
erence numeral 62 and takes the form of a room
with snap action when heat is applied to the ele
thermostat comprising a bimetallic spiral 64 car
ment causing it to warp. The thermal switch I08
rying an arm 66 provided with a pair of spaced
is adapted to be closed when the bimetallic ele
contacts 68 and ‘F6. The contact 68 is cooperable
ment H4 is unheated and the contacts H0 and
with a ?xed contact ‘I2 and the contact ‘I0 is co
‘I 52 are at such time engaged.
operable with a ?xed contact ‘I4. A heater coil
The second circuit is thus closed and may be
16 is provided for accelerating operation of the
traced from the wire 84 by wire I I6, ?xed contact
bimetallic spiral 64. Devices of the type disclosed
IIO, movable contact II2, wire II8, primary coil
schematically herein are well known to those
of the transformer I06, and wire I26 to the wire 86,
skilled in the art and further description of details
The bimetallic element H4 is heated by a coil
is deemed unnecessary.
I22 wrapped around or otherwise disposed in
The general arrangement of the thermostatic
proximity to the element H4 and such coil may
device 62 is such that upon a drop in temperature
be connected at one end by a wire I24 to the wire
of the space being heated by main burner It! the
I I6, at the opposite end by a wire I26 to the mov
bimetallic spiral 64 moves in a clockwise direction
able contact of the second pair of switch contacts
to engage contacts ‘I0 and ‘I4 and thereafter con
48, and by a wire I2'I from the ?xed contact of
tacts 68 and '22; the contact arrangement being
pair 40 to wire I20. An electric igniter I28 is
such that upon initial engagement of contacts ‘I0
provided for igniting the pilot burner 22 and is
and 14 there still remains a gap between contacts
connected to the secondary coil of the second
68 and 72. When the thermostat is satis?ed, the
transformer I66 by wires I30 and I32.
bimetallic spiral 64 will move in a counter-clock
In the operation of the device, the system is
wise direction to disengage contacts 68 and ‘I2
and thereafter to disengage contacts ‘I0 and ‘E4. 60 turned on by opening the main fuel cock If. and
closing the main switch 78 ; it being apparent that
The device thus provides a de?nite temperature
these devices could be interconnected for simul
differential for energizing and denergizing the
taneous operation if desired. Fuel is supplied to
coil 24 of the electromagnetic valve I6. More
the pilot burner 22 through the conduit 20 con
over, neither of the pairs of contacts 68, ‘I2 or 10,
nected to the main fuel pipe I2 but the electro
i4 is required to make or break the full load of
magnetic valve I6 which is biased to closed posi
the electromagnetic valve I6 thus reducing arcing
tion prevents fuel from being supplied to the main
and wear of the contacts. It will be understood
burner I0. Electrical energy is supplied to the
that other commercially available forms of ther
‘primary coil of the second transformer I06
mostatic devices could be substituted and that it
.is not essential that two contacts be employed for " 70 through the second circuit described since the
closing a single circuit.
thermal switch I08 is closed at this time. The
Electrical energy from a commercial source of
supply is controlled by a double-pole main switch
‘I8 connected to the line wires 80. Preferably, a
transformer 82. is connected in the electromag
energizing of the primary coil of the second trans
former I06 causes the magnet plunger 44 of the
resetting device 42 to be picked up. As the sec
ondary coil of the second transformer I96 is now
5
2,406,925
energized, the igniter I28 is also energized and
6
24 is opened by the ?rst contact pair 36 and the
serves to ignite the fuel ?owing from the pilot
electromagnetic valve I6 moves to closed position
burner 22.
to shut-off the flow of fuel to the mainburner II).
When the magnet plunger 44 picks up, the lever
Moreover, the opening of the second contact pair
50 is rotated on its pivotal mounting and causes
40 causes deenergization of the heater coil I22
the third contact pair 52 to be opened. The lever
of the thermal switch I08. However, the con
5d also engages the enlarged head 36 of the stem
tacts III], II2 do not open until after a purge
32 of the electromagnetic device 26 and overcomes
period, the length of which is determined by the
time required by the bimeta-l I I4 to cool.
the bias of the coil spring 34 to reset the arma
ture 30 in engagement with the pole faces of the 10
The recycling character of the system is now
horseshoe magnet 28. The cont-act arm 3‘! at
apparent. After the bimetallic element I it of the
tached to the stem 32 simultaneously causes the
thermal switch I08 has caused the contacts III},
?rst and second contact pairs 38 and 40, respec
I I2 to close, then the sequence of operation is the
tively, to be closed. It is apparent that the ?rst
same as described when the system is ?rst turned
circuit in which the electromagnetic valve coil 24 15 on. As the use of electrical energy from an out
side source is depended upon for resetting the
is included is opened by the opening of the third
safety device only during the short starting pe
contact pair 52 so that no fuel can ?ow to the
riod, it is apparent that the system is adapted for
main burner I0.
safety ‘operation in the event that a power failure
The closing of the second contact pair til en
ergizes the heater coil I22 for the thermal switch 20 occurs. As previously described, the electromag
netic valve I6 is preferably of the commercially
I08 through the described circuit and, after a
predetermined period, the bimetal arm I M warps
available manual-set, automatic-reset type and
can therefore be manually moved to open position
su?iciently to cause the thermal switch I98 to
in the event that a power failure occurs causing
open its contacts IIil, I I2. Thus, the second cir
cuit which includes the primary coil of the trans 25 this valve to be closed. The system will then op
former lot is opened and the magnet plunger 44
erate under control of the thermostatic device 62
and upon resumption of the power supply the
is no longer attracted. Since the secondary coil
electromagnetic valve I G is automatically reset
of the second transformer I05 is now deenergized,
from its manual set position without interruption
the igniter I28 which is in circuit therewith is
likewise deenergized for the duration of the run 30 of the fuel flow. The power consumption is very
ning period of the burner.
low due to the brief nature of the starting period
The pivotal movement of the lever 56 resulting
and the deenergizing of the igniter during the
from dropping of the magnet plunger 44 causes
running period of the burner.
the third contact pair 52 to again be closed. How
While the invention described herein provides
ever, if during this star-ting period the fuel from 35 a relatively simple system \of condition, safety
the pilot burner 22 is ignited by the igniter I28,
control and ignition for gaseous fuel burners, it
then the thermocouple 54 has been sufficiently
will .be apparent that many changes can be made
in the arrangement and combination of parts and
heated by the pilot burner ?ame to energize the
in the ‘details 0f construction herein disclosed
winding 60. The armature 30 will then remain
in its .attracted position [relative to the pole faces 40 within the scope of the appended claims without
departing from the spirit of the invention.
of the horseshoe magnet 28 and the ?rst and sec
ond contact pairs 38 and 40 remain closed. As
I claim:
the third contact pair 52 is also closed, the ?rst
1. In a control system for fuel burners having
circuit is established through the connections de
main and pilot burners and a source of electrical
scribed for the electromagnetic valve I6 provided
energy, comprising in combination, electrically
that the thermostatic device 62 is calling for heat
operable means movable between fuel ?ow per
and has closed its contacts 68—1?. The electro
mitting and preventing positions for controlling
magnetic valve IE will then be operated to open
the supply of fuel to the main burner, an electro
position and fuel will be supplied to the main
magnetic device having contacts operable be
burner I0 where it is ignited by the flame from ,
tween open and closed positions for causing move
the pilot burner 22. It should be noted that the
ment of said means between said positions, a ?rst
second contact pair 40 being closed causes the
circuit including the source, said means and said
heater coil I22 to remain energized and maintain
contacts, a second circuit including the source and
the thermal switch I68 in its open position.
resetting means for said device operative to cause
The system will remain in operation under 0011
closure of said contacts, holding means opera
tively associated with said device for maintaining
trol of the thermostatic device 62 as long as the
pilot burner 22 continues to produce a flame and
said contacts closed independently of said reset
there are no power interruptions. When the
ting means, means responsive to a flame at the
pilot burner for rendering said holding means
thermostatic device 62 is satis?ed, the contacts
68, 12 thereof are ?rst disengaged but the ?rst
operative upon completion of said resetting opera
circuit for the electromagnetic valve coil 24 is
tion, and timing means in said second circuit for
rendering the same inoperative after a predeter
maintained as long as the contacts ‘I0, ‘I4 remain
engaged. The opening of the contacts ‘Hi, 14 is
mined period during which said flame responsive
means has time to become responsive.
accelerated by the provision of the heater ‘coil ‘It
for the bimetallic spiral 64 and the electromag 65
2. In a control system for fuel burners having
netic valve coil 24 is then deenergized to cause
main and pilot burners and a source of electrical
the electromagnetic valve It to close.
energy, comprising in combination, electrically
In the event that the ?ame from the pilot
operable means movable between fuel flow per
mitting and preventing positions for controlling
burner 22 is extinguished, then the thermocouple
54 cools so as to deenergize the winding 60 caus
the supply of fuel to the main burner, an electro
ing release of the armature 30 from the pole faces
magnetic device having first and second contacts
of the horseshoe magnet 28. The contact pairs
operable between open and closed positions, a first
38, 40 are opened by movement of the stem 32
circuit including the source, said means and said
under the bias of the spring 34. Thus, the ?rst
?rst contacts, a second circuit including the
circuit including the electromagnetic valve coil .75 source and resetting means for said device opera
2,406,925
7
8
tive to cause closure of said ?rst and second con
energy, comprising in combination, electrically
tacts, holding means operatively associated with
said device for maintaining said ?rst and second
contacts closed independently of said resetting
operable valve means for controlling the ?ow of
fuel to the main burner and being biased to ?ow
preventing position, an electromagnetic device for
means, means responsive to a ?ame at the pilot
burner for rendering said holding means opera
tween fuel flow preventing and permitting posi
tive upon completion of said resetting operation,
timing means in said second circuit for rendering
tions, said device including a relatively movable
winding and armature, ?rst switch contacts
adapted to be closed by movement of said winding
controlling movement of said valve means be
the same inoperative ‘after a predetermined pe
riod during which said ?ame responsive means 10 and armature together, second switch contacts
also adapted to be closed by the last said move
has time to become responsive, and control means
ment, a ?rst circuit including the source, said
for said timing means responsive to closure of
valve means and said ?rst switch contacts adapt
said second contacts for initiating said period.
ed when closed to cause said valve means to be
3. In a control system for fuel burners having
main and pilot burners and a source of electrical 15 moved against its bias to ?ow permitting position,
thermocouple means exposed to the heat of a
energy, comprising in combination, electrically
?ame at the pilot burner and connected to said .
operable means movable between fuel ?ow per
winding for energizing said device sufficiently to
maintain said ?rst and second switch contacts
closed but insu?iciently to attract said armature
and winding together to close said switch con
tacts, resetting means including primary and sec
ondary transformer coils for moving said arma
means and said ?rst and third contacts, a second
ture and winding together to close said ?rst and
circuit including the source and resetting means
for said device operative to cause closure of said 25 second switch contacts, a second circuit including
the source, said primary coil and switching
?rst and second contacts and opening of said
means, means connected in series circuit with
third contacts, holding means operatively asso
said second switch contacts and in parallel with
ciated with said device for maintaining said ?rst
said second circuit for operating said switching
and second contacts closed independently of said
resetting means, means responsive to a ?ame at 30 means to open said second circuit and cause de
mitting and preventing positions for controlling
the supply of fuel to the main burner, an electro
magnetic device having ?rst, second and third
contacts operable between open and closed posi
tions, a ?rst circuit including the source, said
the pilot burner for rendering said holding means
energization of said primary and secondary coils
operative upon completion of said resetting opera
tion, timing means in said second circuit for ren
dering the same inoperative after a predeter
upon completion of said resetting operation, and
an igniter electrically connected to said secondary
mined period during which said ?ame responsive
?ame prior to said operation of said switching
means has time to become responsive, said third
contacts becoming closed in said ?rst circuit by
operation of said resetting means when said sec
ond circuit is inoperative, and control means for
said timing means responsive to closure of said
second contacts for initiating said period.
4. In a control system for fuel burners having
main and pilot burners and a source of electrical
means.
coil for igniting the pilot burner to produce said
6. In a control system for fuel burners having
main and pilot burners and a source of electrical
energy, comprising in combination, electrically
operable valve means for controlling the flow of
fuel to the main burner and being biased to ?ow
preventing position, an electromagnetic device
for controlling movement of said valve means be
energy, comprising in combination, electrically
tween fuel ?ow preventing and permitting posi
operable means movable between fuel ?ow per- -
tions, said device including a relatively movable
winding and armature, ?rst and second switch
contacts adapted to be closed by movement of
said winding and armature together, third switch
contacts adapted to be opened by the last said
movement but being adapted to be closed inde
pendently of said movement, a ?rst circuit in
cluding the source, said valve means and said
?rst and third switch contacts adapted when
mitting and preventing positions for controlling
the supply of fuel to the main burner, an elec
tromagnetic device for controlling movement of
said means between said positions, said device
including a relatively movable winding and arma- '
ture, thermocouple means exposed to the heat
of a ?ame at the pilot burner and connected to
said winding for energizing said device su?iciently
closed to cause said valve means to be moved
to hold said armature and winding together and
cause said electrically operable means to be held
in said fuel ?ow permitting position but insu?i
ciently to attract said armature and winding to
gether and cause movement of said electrically
operable means from said fuel ?ow preventing po
sition, resetting means including primary and
against its bias to ?ow permitting position, ther
mocouple means exposed to the heat of a, ?ame
at the pilot burner and connected to said winding
for energizing said device su?iciently to maintain
said ?rst and second switch contacts closed but
60
secondary transformer coils connected to the
source for moving said armature and winding to
gether to enable said device to cause movement of
said electrically operable means to said ?uel ?ow
permitting position, a switch connected in series
circuit with said primary coil and the source,
means controlled by movement of said armature
and winding together for operating said switch to
open said circuit upon completion of said resetting
operation, and an igniter electrically connected to 70
insui?ciently to attract said armature and wind
ing together to close said ?rst and second switch
contacts, resetting means including primary and
secondary transformer coils for moving said ar
mature and winding together to close said ?rst
and second switch contacts, a second circuit vin
cluding the source, said primary coil and switch
ing means, means connected in series circuit with
said second switch contacts and in parallel with
said second circuit for operating said switching
means to open said second circuit and cause de
energization of said primary and secondary coils
upon completion of said resetting operation, said
third contacts becoming closed in said ?rst cir
5. In a control system for fuel burners having
cuit by operation of said resetting means when
‘main and pilot burners and a source of electrical 75 said second circuit is opened, and an igniter elec
said secondary coil for igniting the pilot burner
to produce said ?ame prior to said switch op
eration.
2,406,925
10
trically connected to said secondary coil for ignit
ing the pilot burner to produce said ?ame prior
to said operation of said switching means.
means operative to deenergize said resetting
means and igniter after a predetermined period
during which said thermocouple means has time
7. In a control system for fuel burners having
main and pilot burners and a source of electri
to become heated and cause said one pair of
when closed to cause said valve means to be
closed independently of said armature move
ment, switching means responsive to a condition
caused by operation of the main burner, a ?rst
contacts to remain closed.
9. An ignition and control system for fuel
cal energy, comprising in combination, electri
cally operable valve means for controlling the
burners having a main and a pilot burner and
a source of electrical energy, comprising in com
flow of fuel to the main burner and being biased
to ?ow preventing position, an electromagnetic
bination, electromagnetic valve means for the
device for controlling movement of said valve 10 main burner biased to closed position, an electro
magnetic device having a winding and an arma
means between fuel flow preventing and permit
ting positions, said device including a relatively
ture movable between attracted and released po
sitions for controlling the energization of said
movable Winding and armature, two pairs of
valve means for movement thereof to open po
switch contacts adapted to be operated by move
ment of said winding and armature together, one 15. sition, ?rst and second switch contacts associated
with said device and adapted to be closed in the
said pair being closed and the other pair opened
attracted position of said armature,‘ a third pair
' by the last said movement, said other pair being
of switch contacts associated with said device
adapted to be closed independently of said move
and adapted to be opened in said attracted po
ment, a circuit including the source, said valve
sition of said armature but being adapted to be
means and said two pairs of contacts adapted
moved to flow permitting position, thermocouple
means exposed to the heat of a ?ame at the pilot
burner and connected to said winding for, ener
transformer having its primary coil connected
gizing said device sufficiently to maintain said 25 to the source and its secondary connected in a
circuit including said valve means, said switching
one pair of contacts closed but insu?iciently to
means, and said ?rst and third switch contacts,
attract said armature and Winding together to
a second transformer having its primary coil
close said one pair of contacts, electromagnetic
resetting means for said device connected to the
source and operative when energized to move said
armature and winding together to close said one
pair and open said other pair of switch contacts,
said resetting means being operative when de
enorgiaed for closing said other pair of contacts,
and timing means operative to deenergize said
resetting means after a predetermined period
during which said thermocouple means has time
to become heated and cause said one pair of con
tacts to remain closed.
8. In a control system for fuel burners having
main and pilot burners and a source of electrical
energy, comprising in combination, electrically
connected to said source in parallel with the
primary coil of said ?rst transformer, a plunger
magnet operatively associated with the primary
coil of said second transformer and adapted when
the latter is energized for resetting said arma
ture to attracted position and simultaneously
opening said third pair of contacts, said plunger
magnet being adapted when said second trans
former is deenergized for closing said third pair
of contacts, thermocouple means exposed to the
heat of a flame at the pilot burner and connected
to said winding for energizing said device suf?
ciently to retain said armature in attracted po
sition, an igniter for the pilot burner connected
to the secondary of said second transformer and
operable valve means for controlling the ?ow of
adapted when energized to produce said ?ame,
iuel to the main burner
being biased to flow
preventing position, an electromagnetic device 45 a thermal switch in circuit with said primary of
said second transformer and being closed when
‘for controlling movement ‘of said valve means
cold, and a heater coil for said thermal switch
between fuel ?ow preventing and permitting po
adapted to cause opening thereof and said do
sit-ions, said device including a relatively mov
energizaticn of said second transformer and ig
able winding ans. armature, two pairs of switch
niter after a predetermined period during which
contacts adapted to be operated by movement
said thermocouple means has had time to become
of said winding and armature together, one said
heated suf?ciently to cause said armature to be
pair being closed and the other said pair being
retained in attracted position, said heater coil
opened ‘by the last said movement, said other
and second pair of contacts being in series cir
pair being adapted to be closed independently
of said movement, a circuit including the source, 55 cuit and jointly in parallel with said thermal
switch and said primary of said second trans
said valve means and said two pairs of contacts
former for thereafter maintaining said thermal
adapted when closed to cause said valve means
switch open during such time as said armature
to be moved to now permitting position, thermo
remains attracted.
couple means exposed to the heat of a flame at
10. In a control system for fuel burners having
the pilot burner and connected to said winding
main and pilot burners and a source of elec
for energizing said device sufliciently to maintain
trical energy, the combination of electrically op
said one pair of contacts closed but insu?iciently
erable means connected to the source and being
to attract said armature and winding together
movable between positions for controlling the
to close said one pair of contacts, electromag
netic resetting means for said device including 65 supply of fuel to the main burner, an electro
vmagnetic device having contacts movable be
primary and secondary coils of a transformer,
tween open and closed positions for controlling
said primary coil being connected to said source
and operative when energized to cause said re
setting means to move said armature and wind
ing together to close said one pair and open
said other pair of switch contacts, said resetting
means being operative when deenergized for clos
the energization, of said electrically operable
means, means responsive to a flame at the pilot
burner for controlling the energization of said
device, and a second electrically operable means
connected to the source and cperatively associ
ated with said electromagnetic device for reset
ing said other pair of contacts, an igniter elec
ting the same to cause closure of said contacts.
trically connected to said secondary coil for ignit
11. In a control system for fuel burners having
ing the pilot burner to produce said ?ame, and 75
2,406,925
11
main and pilot burners and a source of electrical
energy, the combination of electrically operable
means connected to the source and being mov
able between positions for controlling the supply
12
for movement thereof to ?ow preventing position,
means for resetting said thermomagnetic switch
means in said ?rst position including a second
electrically operable means energized from the
of fuel to the main burner, an electromagnetic
device having contacts movable between open
and closed positions for controlling the energiza
tion of said electrically operable means, thermo
thermomagnetic switch means to said ?rst posi
tion for causing deenergization of said second
electrically operable means, and control switch
electric means responsive to the heat of a ?ame
means responsive to changes in a condition to be
source, means responsive to movement of said
at the pilot burner for controlling the energiza 10 controlled for controlling the energization of the
?rst said electrically operable means for move
tion of said device but being incapable of causing
ment thereof between ?ow preventing and per
closure of said contacts, a second electrically op
mitting positions independently of said thermo
erable means connected to the source and oper
magnetic switch means.
atively associated with said electromagnetic de
14. A control system for fuel burners having
vice for resetting the same to cause closure of
main and pilot burners and a source of electrical
said contacts, and timing means responsive to
closure of said contacts for causing deenergiza
energy, comprising in combination, electrically
tion of said second means after a predetermined
operable means connected to the source and be
period during which said thermoelectric means
ing movable between positions for controlling the
has time to become heated.
20 supply of fuel to the main burner, an electro
magnetic device having contacts operable be
12. In a control system for fuel burners having
tween open and closed positions for controlling
main and pilot burners and a source of electrical
energy, the combination of electrically operable
energization of said electrically operable means
means connected to the source and being mov
for movement thereof between said positions,
able between positions for controlling the supply
thermoelectric means responsive to a ?ame at
the pilot burner for controlling the energization
of fuel to the main burner, a ?rst electromag
netic device having a pair of contacts movable
of said device-means for resetting said device to
between open and closed positions for controlling
cause closure of said contacts including a second
the energization of said electrically operable
electromagnetic device energized from the source,
means, thermoelectric means responsive to the 30 timing means responsive to closure of said con
heat of a ?ame at the pilot burner for control
tacts for causing deenergization of said second
ling the energization of said device but being in
device after a predetermined period during which
capable of causing closure‘ of said contacts, a
said thermoelectric means has time to become
second electromagnetic device connected to the
heated by said ?ame, and control switch means
source and having a pair of contacts controlling
responsive to changes in a condition to be con
the energization of said electrically operable
trolled for controlling the energization of said
means and a movable armature for operating
electrically operable means for movement thereof
between said positions independently of the ?rst
said second pair of contacts, said armature be
ing operatively associated with said ?rst electro
said electromagnetic device.
magnetic device for resetting the same to cause 40
15. A control system for fuel burners having
closure of said ?rst pair of contacts while simul
main and pilot burners and a source of electrical
taneously opening said second pair of contacts
energy, comprising in combination, electrically
to prevent energization of said electrically oper
operable means connected to the source and be
able means during the resetting operation, and
ing movable between positions for controlling the
timing means responsive to closure of said ?rst l‘I supply of fuel to the main burner, an electromag~
pair of contacts for causing deenergization of
netic device having ‘contacts operable between
said second electromagnetic device after a pre
open and closed positions for controlling energi
determined period during which said thermoelec
zation of said electrically operable means for
tric means has time to become heated, said arma
movement thereof between said positions, ther
ture thereby causing closure of said second pair
moelectric means responsive to a ?ame at the
of contacts while said ?rst pair of contacts re
pilot burner for controlling the energization of
mains closed to cause energization of said elec
said device, means for resetting said device to
trically operable means.
cause closure of said contacts including a second
13. A control system for fuel burners having
electromagnetic device energized from the source,
main and pilot burners and a source of electrical
igniting means for the pilot burner, timing means
energy, comprising in combination, electrically
responsive to closure of said contacts for causing
operable means connected to the source and be
deenergization of said second device and said
ing movable between fuel ?ow preventing and
‘igniting means after a predetermined period dur
permitting positions for controlling the supply
ing which said thermoelectric means has time to
of fuel to the main burner, thermomagnetic (30 become heated by said ?ame, and control switch
switch means responsive to a ?ame at the pilot
means responsive to changes in a condition to be
burner and operable between a ?rst position for
controlled for controlling the energization of
causing energization of said electrically operable
said electrically operable means for movement
means for movement thereof to ?ow permitting >
thereof between said positions independently of
position and a second position for causing de
the ?rst said electromagnetic device.
energization of said electrically operable means
CHARLES K. STROBEL.
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