Патент USA US2405807код для вставки
Aug. 13, 1946. ‘ ‘ P. ARANT ‘ I 2,405,807 BURNER CONTROL SYSTEM Filed Sept. 24, 1941 / 3 3_. 0 7 #4 n.9mra: aW Lz .m ‘ 4 w v? z _P 87,59 M N“/ a. v 2/0 .Q F .Tw@3?ve,0%% MM \\02Q .7456 2“w/ Tva J_6.5 I | |w\u"luv ‘wk _711%” _.4w.w;3..\~ /WI”55L“we6n”\. Z64.q _ u a P. m n w, a _. am ,9 MW . on . 9m H 6/ w 1% m Ml“ ., m M M. . ,up a M ,Tr 7/ U5... M . m, 2 J@531 @A _i Z.5/._ 5,a, a aF?a rL, r 5 a, W 6 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.