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Патент USA US3072187

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Jan. 8, 1963
A. A. FENNELL
v3,072,177
BURNER SAFETY CONTROL
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INVENT R.
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Jan. 8, 1963
3,072,177
A. A. FENNELL
BURNER SAFETY. CONTROL
Filed July 19. 1957
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Jan. 8, 1963
A. A. FENNELI.
3,072,177
BURNER SAFETY CONTROL
Filed July 19. 1957
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United States4 Patent
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3,072,177
Patented Jan. 8, 1963
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3,072,177
this pipe. This valve is a spring biased solenoid operated
valve of known construction such that when the solenoid
28 thereof is energized the valve is ope-n and when the
solenoid is deenergized spring means causes the valve
BURNER SAFETY CÜNTRUL
Anthony A. Fennell, Homewood, lll.
>(379 E. 147th St., Harvey, Ill.)
Filed July 19, 1957, Ser. No. 673,016
3 Claims. (El. 153-423)
to close.
Adjacent the burners are detectors or sensing devices
30, 32, 34, 36, 38 and 40. These detecting or sensing
The present invention relates to a novel control system,
and more particularly to a novel system adapted to con
trol burners and the like.
Industrial furnaces are frequently provided with a plu
rality of burners which utilize gas, oil or other suitable
fuels. Some means must be provided for shutting off
devices are of known construction and may, for example,
be of a type which generates an electric signal in re
spense to heat or light from the flame when the burner
all burners if any one of them goes out so that unburned
fuel is not introduced into the furnace from such ex
ln accordance with a feature of the present invention
the control system is provided with only a single relay 42
for controlling the fuel shut off valve 26. The relay is
preferably of a fast acting type and of known construc
tion and has terminals connected with the solenoid 28
by wires 44 vand 46, Power is supplied to the relay
through lines 48 and 50. Safety switch means generally
designated by the numeral 52 is inserted in the line 50
tinguished burners and subsequently ignited by one of the
other burners. It will be appreciated that fuel ignited in
this manner might well cause an eXplosio-n. Various con
trol systems have heretofore been proposed, which sys
is lit. Alternatively, the sensing or detecting devices may
be of the resistance type which changes electricity con
ducting characteristics in accordance with temperature.
tems usually incorporate a separate detector for each
burner capable of sensing the presence or absence of a
flame, and a separate control circuit for each detector.
for shutting olf power to the relay and thereby causing
`Such heretofore proposed control circuits are costly so
the fuel shut off valve to close in the event of a failure
that the cost of a furnace installation is high especially
of a portion of the control system as described more fully
when the furnace has a considerable number of burners. 25 hereinbelow.
An important object of the present invention is to pro
The control system is provided with switch means gen~
vide a novel control system for a plurality of burners,
erally designated by the numeral 54 for .successively and
which system is materially simplified and eliminates
separately connecting each of the sensing devices Sil-4G
duplication of many parts heretofore believed to be neces
with the relay 42. It will be appreciated that the switch
sary so that the system may be installed and maintained 30 means 54 may be constructed in various ways, but for
relatively easily and economically.
A more specific object of the present invention is to
provide a novel control system of the above described
type which utilizes separate detectors or fiame sensing de
vices for each burner and which is greatly simplified as
compared with heretofore proposed systems in that it in
cludes only a single control circuit successively and sepa
rately connectable with each of the detectors or sensing
the purpose of illustrating the present invention the switch
means 54 is provided with a plurality of fixed switch con
tacts 56, 58, 60,
contacts 68, 70,
are respectively
wires 80 and 82
94.
62, 64 and 66 cooperable with movable
72, ’74, 76 and '78. The fixed contacts
connected with the relay by common
and branch wires 84, 86, 88, 90, 92 and
The movable contacts are respectively mounted on
movable fingers 96, 98, 100, 102, 104 and 1616 which
devices so as to accomplish periodic inspection of each
are connected with one terminal of the sensing devices
40 30-40 respectively by wires 108, 110, 112, 114, 116 and
of the burners.
Still another object of the present invention is to pro
118. Other terminals of the sensing devices are con
vide a novel control system of the type mentioned in
nected to the relay by wire 120 and branch wires 122,
the pre"eding paragraph which is constructed so as to
124, 126, 128, 130 and 132. ’
shut off the burners in the event of failure of the system
Considering FIG.> 4, the relay 42 will be seen to> in
45 clude a coil 200 which is connected between line 48 and
to proceed with successive inspection of the burners.
Other objects and advantages of the present invention
wire 80. Energization of coil 200 causes a magnetic ele
will become apparent from the following description and
the accompanying drawings wherein
ment 202 to operate a movable contact 204, contact 2114
being electrically connected to both line 50 and wire 126.
Relay 42 also includes a fixed contact 2h63 and when
50 magnetic element 292 directs contact 204 to make elec
incorporating features of the present invention;
PIG. 2 is a schematic view showing a slightly modified
trical connection> with contact 206, a circuit is completed
control system;
from line Sil, through the contacts 204 and 2íl6-to wire
FIG. 3 is a schematic view showing another slightly
46, through solenoid 28 and through-wire 44 to line 48.
modified form of the present invention;
As will be recognized, coil 201i remains energized to pre
FIG. 4 is a detailed diagrammatic showing of the fuel 55 serve completion of the circuit through contacts 204 and
206 to the operating solenoid 23 of valve 26 only so long
supply control relay employed in the system of FIG. 1;
as switch means 54 and safety switch means 52 continue
FIG. 5 is a detailed diagrammatic showing of the
the circuit from line Sil to wire 8% in a completed condi
sensing circuit relay incorporated in the modified control
tion.
system of FIG. 2; and
FIG. 6 is a detailed diagrammatic showing of the pulse 60 The switch means 54 is provided with a plurality of
rotatable cams 134, 136, 138, 140, 142 .and 144 respec
*timer employed in the modified form of the invention il
tively engageable with cani elements 146?, 148, 150, 152,
lustrated in FIG. 3.
154 and 156 on the fingers for positioning the fingers to
In FIG. 1 there is shown a control system 10 >for con
v'trolling burners 12, 14, 16, 18, 20 and 22 in a furnace 65 open or close the switch contact points. The rotatable
cams are all fixed on a shaft 158 which is continuously
or the like. While six burners have been shown for the
driven by an electric motor 169. The rotatable cam
_purpose of illustrating the present invention, it will be
members are constructed and fixed on the shaft 15S so
>appreciated that the advantages of the present invention
that the pairs of switch contact points are successively
may be realized when the control system is constructed
opened and closed and so that only one pair of the con
for use with at least two burners and any desired larger 70 tact points is closed at one time to accomplish inspection
_. number of burners.
Fuel is supplied to the burners
of a given burner. The construction may be such that
from a common pipe 24, and a valve 26 is connected in
there will be a slight overlapping of the periods during
FIG. 1 is a schematic view showing a control system
3,072,177
4
operated the cycle of opening and closing of the switches
will be continuously repeated. As a result each of the
in turn opens the circuit from line 58a through the con
tacts of relay 42a to the line 48a.
FIG. 3 shows another slightly modified form of the
present invention which is similar to the above described
structures as indicated by the application of identical
reference numerals with the sufiix “b” added to corre
detector devices4 will be connected periodically with the
relay.
sponding elements. This embodiment also differs pri
marily in the construction of the safety switch means 52b.
which successive pairs of points are closed so as to pre-`
vent the relay from closing the shut off valve as the relay
is switched from one sensing device to the next. It will
be appreciated that since the motor 161i) is continuously
In this embodiment the switch means 52b comprises a
It will be appreciated that in the event one of the burn
ers goes out, its associated sensing or detector device will 10 pulse type or periodically energized timer 182. Such
timers are of known construction and usually include a
signal the relay» 42 upon being periodically connected with
holding circuit which must be periodically energized in
the relay so that the relay will function to close the valve
order to prevent opening of the main power line contacts.
26. In order' to prevent an undue lapse of time between
In the present installation the timer holding circuit has
the instant a burner goes out and the moment in which
its associated sensing device is subsequently connected 15 terminals connected. by wires 184 and 186 to a fixed
contact 188 and a contact 190 on a movable finger 192.
with the relay, it is necessary to rotate the cam shaft 158
A cam 194 fixed on the cam shaft 158b is constructed
ata speed which enables the entire cycle to be completed
so as to operate the movable finger 192 to close the con
inA a relatively short time. While this time interval may
tacts 188 and 19t) periodically during each-revolution of
be varied somewhat for different installations, it should
be~ as short asl possible and as a result each burner will 20 the cam shaft. Thus, if for any reason the cam shaft is
stopped the timer will not be periodically energized and
be inspected for no more than a few seconds during each
it will functionto disconnect the relay 42h from the main
scanning cycle. Thus the relay 42 must be a fast oper
ating type which is capable of causing the fuel shut off
power source.
Turning to FIG. 6 for a more detailed consideration
of the scanning devices and before the next scanning de 25 of the pulse timer 182, line 48b will be seen connected
to wire 184Y through a coil 218 and to relay 42b through
vice is connectedä with the relay.
valve to be closed upon receiving a brief signal from one
In the event of a failure of the motor 161B or some other
a fixed contact 228<and a movable contact 222. Coil 21S
operates amagnetic element 224 toactuatethe movable
mechanical breakdown which would cause the cam shaft
contact 222, magnetic element 224 being mechanically
158 to stop it would be possible for a single sensing or
detector device to remain connected with the relay 42. 30 connected to an air dashpot 226. Movable contact 222
Under such condition` it might be possible for a burner
associated with another sensing device to go` out without
being detected. However, in accordance with a feature of
is biased normally to open the circuit through the con
tacts22t1 and 222 by means of a tension spring 228.
Thus, spring 228 biasesV the contacts 222 and 220 into
the present invention this possibility is eliminated by the
open configuration whereas air dashpot 226 opposesthis
is supplied for energizing the relay through the wires 176
said burners, said circuit meansvincluding a plurality of
sensing circuits connected inparallel and.. adapted to be
individually associated with said burners externall to the
flames thereof, each of said sensing- circuits including a
provision ofthe above mentioned switch means 52. In 35 action in order to delay opening of the contacts for a
short time interval after a deenergization of coil 218. As
this embodiment, the switch means S2 has a fixed contact
will be recognized, a failure in theV periodic closing, of
162 and a cooperable contact 16a which is axially mov
contacts 188 and 190 opens theV circuit from line 50h,
able on a rotatably supported shaft 166. A ñy weight
through wire 186, wire 184 and coil 218 to the line 48b.
governor type device 168 is driven by the shaft 166 for
raising the contact 164 into engagement with the contact 40 Upon deenergization of coil 218 in this manner, spring
228 eventually overcomesthe mechanical resistance of
162. The shaft 166 is in turn driven from the cam shaft
dashpot 226 to open the contacts 220» and 222., This
158 through bevel gears 178 and 172. Thus, in the event
opening of the circuit through contacts> 220 and 222V in
the cam shaft 158 is stopped for any reason, the shaft
effect opens the circuit to the coil of relay 42b to which
166v will also be stopped and the fly weight device will
contact 222V is connected by aV wire23fi».V A wirev 232 con
cause thecontact 164` to be disengaged from the contact
nects the movable contact of relay 42b. to; the, line Siìb.
162. When thisoccurs power to the relay 42 is shut off
While the preferred embodiments of theV present inven
and the fuel valve 26 is closed.
tion have beenshown and described herein, it-v is obvious
FIG. 2-shows a slightly modified form of the present
thatmany structural details‘may be changed without de
invention which is similar to the above described control
system as indicatedI by the application of identical refer 50 parting from the spirit/and scope of the appended claims.
The invention is claimed as follows:
ence numerals with the suffix “a” added to corresponding
1. A control system. for a plurality of burners com
elements. Th's embodiment differs primarily in the con
prising:v valve meansV forv operating. said burners; relay
struction of the safety switch means. More specifically,
means for` regulating said valve means; circuit means for
the safety switch means 52a` comprises a relay 174 for
connecting portions of the wire 50a only when electricity 55 actuating. said relay means inrresponsev to thecondition of
and 178. These wires are connected with terminals of
a small generator 180 which is driven from the cam shaft
158a through gears 170:1 and 172a. Thus, whenever the
sensor adapted to be disposed> adjacent a burner anda
cam shaft 158a is stopped, the generator 180 is stopped 60 switch connected in series with said` sensor; rotatable shaft
so that the relay 174 is deenergized and the relay 42a is
meansta plurality of cams affixed to said shaft means and
disconnected from the main power source.
arranged to operate said switches in a repetitive sequence;
With specific reference to FIG. 5, the relay 174V will
and means responsive to the rotation, of said shaftmeans
bey seen to include a coil 288 which is-connected in elec
for de-energizing the circuit means upon cessation of rota
trical series circuit with generator 180 by the wires 176 65 tion of any part of said shaft means.
and 178. The relay 174 also includes a magnetic ele
2. A control system for a plurality of burners compris
ment 210 which is controlled by the coil 208 to actuate
ing: valve means for operating said’burners; relay means
a movable> contact 212. The movable contact 212 is ar
for regulating said valve means; circuit means for actuat~
ranged to coact with a fixed contact 214 in completing a
70 ing said relay means in response to the condition of said
circuit from linel 50a, through the contacts 212 and 214
burners, said circuit means including a plurality of sens
and through a wirer216- to the movable contact of relay
ing circuits connected in parallel and adapted to be in
42a., As will be recognized, cessation of the operation
dividually associated with said burners external to the
of generator 180 serves to deenergize coil 208 whereby
dames thereof, each of- said sensing circuits including a
tov open the circuit through contacts 212 and 214. 'Ihis 75 sensor adapted to be disposed adjacent a burner and, a
5
8,072,177
Q5
normally open switch electrically connected in series with
source upon said control means being periodically ener
said sensor; rotatable shaft means; a plurality of cam
gized, said rotationally responsive means further includ
ing means periodically operated upon rotation of said
shaft means for periodically energizing said control means.
means afñxed to said shaft means and arranged momen
tarily to close said switches in a repetitive sequence; a
power source; and control means connected in circuit 5
between said source and said relay means, including a con
trol switch operated by a cam on said shaft, said control
means passing power to said relay means when said con
trol switch is regularly and periodically closed by said
cam, said control means blocking power to said relay 10
means upon interruption of the periodic operation of said
control switch.
3. A control system according to claim 1 wherein said
rotationally responsive means includes periodically en
ergizable control means connected to said circuit means for 15
maintaining said circuit means connected to a power
References Cited in the tile of this patent
UNITED STATES PATENTS
2,291,385
2,295,045
2,304,200
2,327,690
2,581,942
2,692,962
2,736,371
Gossett ______________ __ July 28,
Mettler ______________ __ Sept. 8,
Plein et al. _____________ __ Dec. 8,
Ackerman ____________ __ Aug. 24,
Collins et al ____________ __ Jan. 8,
Thomson ____________ __ Oct. 26,
Rafenstein ____________ __ Feb. 28.
1942
1942
1942
1943
1952
1954
1956
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