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May 10, 1938. 2,117,021 L. D.‘ COTEA EXPANDING FLAME OIL BURNER‘ SYSTEM Filed April 28, 1934 saw THERMAL SAFETY @) 0 Ass as BURNER MOTOR /7a LOW / CAPACITY OIL. VALVE CABKCITY OIL VALVE 69-‘ 7| I 63 33 21 STACK sw. anaemic» LESTER D. COTEA dttwwu Patented May 10, 1938 2,117,021 UNITED STATES PATENT OFFICE I 2,117,021 EXPANDING FLAME on. BURNER SYSTEM Lester D. Cotea, Dayton, Minn, assignor to Min neapolis-Honeywell Regulator Company, Min neapolis, Minn., a corporation of Delaware Application April 28, 1934, Serial No. 722.907 1 Claim. (Cl. 7158-—28) description and theaccompanying single drawing The present invention relates to improvements in fuel burning systems and is particularly con cerned with the provision 'of a fuel burning sys tem in which the supply of fuel is increased after 5 combustion has been properly established. The object of the present invention is the provision of a fuel burning system including valve . mechanism adapted to supply either a large or a small amount of fuel to a burner, and to entirely 10 interrupt the supply of fuel thereto, together with means for initially operating the valve mecha nism in such manner as to cause the same to supply a small amount of fuel to the burner which, if successfully ignited, is thereafter in 15 creased to a larger supply. In this manner, a trial ignition period can be instituted without delivering a large amount of fuel to the burner and if this ignition period is successful in es 2O tablishing combustion, then the full desired sup ply of fuel is‘ established thereby making it pos sible to check the operation of the system with out delivering a very large supply of fuel‘ to the burner in the event ignition is not successful. The inventionfurther includes the usual safety 25 mechanism by which the system is rendered in which is a diagrammatic showing of one form of the present invention. Referring to the drawing, the valve mechanism comprises a low capacity valve III which is cp- 5 erated by an eletromagnetic winding ll and a high capacity valve I 2 which is operated by an electromagnetic winding l3, the arrangement be ing such that valves l0 and I2 are moved to open position upon energization of their respective 10 electromagnetic windings l2 and I3. The fuel supplied by the low capacity valve i2 is ignited by an electrically operated ignition means l4. Preferably, the system includes a burner motor I 5 which serves to supply the combustion sup 15 porting vair and atomizes or mixes the fuel and air in any of the manners now well-known in the art. The system is controlled by a main control in dicated generally at I6 which is herein shown as 20 comprising a room thermostat which includes a bimetallic coiled element I‘! having one of its ends ?xed as indicated at l8. The other end of bimetallic element l1 controls a contact blade l9 and a contact blade 20. When the room tem- 25 operative in case combustion is not successfully falls, contact blade I9 ?rst engages a established and the arrangement is such that the perature contact 2| and upon further fall in the room tem large supply of fuel cannot be furnished to the perature contact blade burner before the safety mechanism has checked vSimilarly, upon a room 20 engages a contact 22. temperature rise, the con 30 the operation of the apparatus. In the speci?c embodiment of the invention tact blade 20 ?rst disengages its contact 22 and 30 thereafter the contact blade l9 disengages ‘its herein disclosed, the *valve mechanism’ comprises contact 2|. a pair of valves one of which is preferably a low The system further includes a thermal safety capacity valve and the other of which is pref 35 erably a high capacity valve. The low capacity switch which comprises a switch 25 that is ther valve is initially energized under the command mally operated and an electric heating element 26 of a main control device and, in the event the for operating the same. Such thermally operable supply of fuel furnished by this low capacity valve switches are well-known in the art and the is successfully ignited, then the high capacity thermal safety switch utilized in the present in 40 valve is energized and the low capacity valve is vention may well take the form shown in Fred deenergized. The ignition means for igniting the erick S. Denison application Ser. No. 226,395 40 which was ?led October 15th, 1927. fuel supply to the burner is controlled simul The system of the present invention further taneously with the low capacity valve in the pre includes a combustion responsive switching mech ferred form of the invention. Also, it is pref 45 erable to provide a burner motor which is ener anism which preferably takes the form of a, slip friction stack switch generally indicated at 28. gized the whole time that the system is in op eration. . The stack switch 28 includes ?rst cold and hot - The system also is preferably arranged to give a recycle upon a failure of ?ame or momentary power failure. slip friction mechanism, the arrangement being Other objects of the invention will be found such that switch arm 3| engages contact 29 in in the'drawing, the following description and in the appended claim. 55 switches comprising contacts 29 and 30 and a switch arm 3| that is operated through suitable - For a better understanding of the invention, reference may be had to the following detailed the absence of combustion and engages contact 30 upon the establishment of combustion. The arrangement is such that switch arm 3| engages contact 30 prior to disengaging contact 29 upon establishment of combustion but does not en 2,117,021 2 cold electrodes 33 and the bridging mercury 21 of mercury switch 32 and wire 1| at which point disengaging contact 36 upon cessation of com the circuit branches, one part going by way of bustion. The stack switch 26 further includes‘ wire 12, ignition means l4 and wire 13 to line second cold and hot switches comprised by a mer 46, whereas the other portion goes -by way of cury switch 32 having a pair of cold electrodes wire 14, electromagnetic winding H of low ca 33 and a pair of hot electrodes 34 adapted to be pacity valve l6, wire 15, and wire 16 to line 46. bridged by a body of mercury 21. Stack switch In this manner, upon a call for heat by the mechanisms of this general character are well thermostat IS, the burner motor I5 is en known in the art and the one diagrammatically room ergized and a small supply of fuel is furnished 10 illustrated herein may well take the general form 10 shown in Figs. 2 and 3 of Frederick S. Denison to the burner which should be ignited by the ignition means l4. In the event ignition is not gage contact 29 until a delayed interval after application Ser. No. 697,687, ?led November 11th, 1933. The room thermostat l1 and the stack switch 28 cooperate in the control of a relay 35 which comprises a relay coil 36 that attracts an arma ture 31 when energized. An armature 31 con trols switch arms 38, 39 and 46 to move the same into engagement with respective contacts 4|, 42 20 and 43 upon energization of relay coil 36. High voltage electrical power is furnished to the system by line wires 45 and 46. Low voltage electrical power is furnished by a step-down transformer 41 having a low voltage secondary 25 48 and a high‘voltage primary 49 which is con nected to line wires 45 and 46 by wires 56 and 5|. successfully established within a predetermined timed period, the heating element 26 will cause opening of safety switch 25 whereupon the system 15 will be rendered inoperative until manual inter vention. On the other hand, if combustion is successfully established within this period, switch arm 3| will move into engagement with contact 20 36 and thereafter will disengage contact 29. Likewise, mercury switch 32 will tilt to its oppo site position wherein the hot electrodes 34 are bridged by the mercury 21 thereof. Engagement of switch arm 3| with contact 36 immediately establishes a maintaining circuit for 25 relay coil 36 which maintaining circuit opera The remaining circuit connections will be de scribed under the heading “Operation”. Operation 30 With the parts in the position shown, the room temperature is above the desired value and the relay coil 36 is deenergized. The cold switches comprising switch arm 3| and contact 29 and 35 the electrodes 33 of mercury switch 32 are both closed and the combustion responsive hot switches ' comprised by arm 3| and contact 36 and the electrodes 34 of mercury switch 32 are both opened indicating that there has been a decrease 40 in the temperature of combustion. Low and high capacity valves l6 and |2 are both closed and the ignition means |4 and‘burner motor l5 are both deenergized. When the room temperature drops so as to bring contact blades l9 and 26 sequentially into engagement with their contacts 2| and 22, an energizing circuit for the relay coil 36 and heat ing element 26 is established as follows: second ary 48, wire 55, safety switch 25, wire 56, contact 50 2|, contact blades l9 and 26, contact 22, wire 51, wire 58, switch arm 3|, cold contact 29, wire 59, heating element 26, wire 66, wire 6|, relay coil 36 and wire 62_to the other side of second ary 48. Energization of relay coil 36 , moves 55 switch arms 38, 39 and 46 into engagement with their respective contacts 4|, 42 and 43. Engage ment of switch arm 39 with its contact 42 es tablishes a holding circuit for relay coil 36 and heating element 26 as follows: secondary 48, wire 55, safety switch 25, wire56, contact 2|, contact blade |9, bimetallic element l1, wire 63, contact 42, switch arm‘ 39, wire 64, wire 58, switch arm 3|, contact 29, wire 59, heating ele ment 26, wire 66, wire 6|, relay coil 36 and wire ~65 62 to the other side or secondary 48. Engagement of‘ switch arm 46 with contact 43 establishes, energizing circuits for burner motor |5, ignition means l4 and low capacity valve I6. The energizing circuit for burner motor I5 is as follows: line 45, wire 65, contact 43, switch arm 46, wire 66, wire 61, burner motor l5, and wire 68 toline 46. The energizing cir cuits for ignition means l4 and low capacity valve W are as follows: line 45, wire 65, contact 43, switch arm 46, wire 66, wire 69, wire 16, tively deenergizes heating element 26 by estab lishing a shunt therearound. This maintaining circuit is as follows: secondary 48, wire 55, safety switch 25, wire 56, contact 2|, contact blade l9, bimetallic element |1, wire 63, contact 42, switch arm 39, wire 64, wire 56, switch arm 3|, contact 36, wire 19, switch arm 38, contact 4|, wire 86, wire 6|, relay coil 36 and wire 62 to 35 the other side of secondary 46. Then as soon as switch arm 3| disengages contact 29, the original energizing and holding circuits for relay coil 36 and heating element 26 are interrupted. Move ment of mercury switch 32 to its hot position 40 opens the circuit between cold electrodes 33 to interrupt the energizing circuits for ignition means l4 and low capacity ‘valve l6. Closure of the circuit through hot electrodes 34 of mer cury switch 32 however establishes an energiz ing circuit for high capacity valve |2 which is as follows: line 45, wire 65, contact 43, switch arm 46, wire 66, wire 69, wire 86, hot electrodes 34 and the mercury 21 of mercury switch 32, wire 83, electromagnetic winding l3 of high ca 60 pacity valve 12, wire 64, and wire 16 to line 46. The system is now in normal operation, com bustion having been established and resulting in an increase in the supply of fuel. When the room temperature begins to rise so 55 as to move contact blade 26 from engagement with contact 22, relay coil 36 will be maintained energized either by the previously described hold ing circuit or by the maintaining circuit. How ever, when the room temperature rises sufliciently to additionally move contact blade l9 from en gagement with contact 2|, then the maintaining circuit will be interrupted, as will be the hold ing'circuit if switch arm 3| has not as yet dis engaged contact 29, and the relay coil 36 will be deenergized. This relay. coil cannot thereafter be again energized until such time as the room temperature falls sufficiently to bring both con tact blades I9 and 26 into engagement with their respective contacts 2| and 22 and until switch 70 arm 3| disengages contact 36 and'engages con tact 29. In the event there should be a failure in the . supply of electrical power while the system is in operation, relay coil 36 will be deenergized and 2,117,021 _10 cannot be again energized upon resumption of power unless the stack temperature has de creased sufficiently to move switch arm 3| from' engagement with contact 30 and into engage ment with contact 29. Also, at this time, both blades I9 and 20 of the room thermostat l6 must be in engagement with their contacts 2| and 22 in order to reenergize relay coil 36. In the event there should be a failure of ?ame during normal operation, switch arm 3| will ?rst disengage con tact 30 whereupon relay coil 36 will be deener gized after which, upon engagement of switch all of the other usual features such as a recycle upon power failure or ?ame failure, together with control of the ignition means. by those skilled in the art and I therefore intend to be limited .only by the scope of the appended claim. I claim: vention. ‘ ‘ From the foregoing description, it will be ob-v served that the present invention provides a trial ignition period in which a relatively small amount of fuel is supplied. If ignition is not established, 25 the system is shut down without very ‘much fuel having been delivered to the. burner or combus tion chamber. In the event'combustion is suc cessfully established, the supply of fuel is in creased to the desired amount. In this manner, 30 if the system is not operating properly a much smaller amount of fuel is supplied to the burner before the system is rendered inoperative by the safety mechanism. l ‘ In combination, a room thermostat, a thermal 10 ‘safety switch including an electric heating ele arm 3| with contact 29 and if the room thermo 20 , It will be apparent that many changes in the speci?c arrangement shown herein can be made 6 ment, a relay coil, a control switch and a load stat switches are both closed, relay coil 36 and 15 heating element 26 will again be energized to es tablish anew trial ignition period. If combus tion is not successfully reestablished at this time the system will be rendered inoperative by the safety switch and remain so until manual inter 3 It will also be noted that the invention provides switch closed thereby when energized, ?rst cold and hot combustion responsiveswitches overlap 15 pingly controlled upon a rise in the temperature of combustion, an energizing circuit for said re lay coil and heating element in series including said room thermostat, safety switch and ?rst cold combustion responsive switch, a holding circuit 20 for said relay coil including said room thermo stat, ?rst hot combustion responsive switch, and said‘ control switch, a. burner motor, ignition means, ‘a low capacity fuel valve, second hot and cold combustion responsive switches, circuit con 25 nections controlled by said load switch and sec and cold switch for energizing said low capacity .valve and said ignition means, an energizing cir cuit for said burner motor controlled, by said load switch, a high capacity fuel valve, and an 30 energizing circuit therefor controlled by said load switch and said second hot switch. . _ LESTER D. CO‘I'EA.