US2117021A - Expanding flame oil burner system - Google Patents

Description

May 10, 1938. L. COTEA EXPANDING FLAME OIL BURNER SYSTEM Filed April 28, 1934 THERMAL SAFETY ss as BURNER MOTOR LOW CAPACITY CABKCITY OIL. VALVE OIL VALVE STACK sw.

anaemic LESTER D. COTEA dttwwu Patented May 10, 1938 UNITED STATES PATENT OFFICE I 2,117,021 EXPANDING FLAME on. BURNER SYSTEM Application April 28, 1934, Serial No. 722.907 1 Claim. (Cl. 158-28) The present invention relates to improvements in fuel burning systems and is particularly concerned with the provision 'of a fuel burning system in which the supply of fuel is increased after 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 interrupt the supply of fuel thereto, together with means for initially operating the valve mechanism in such manner as to cause the same to supply a small amount of fuel to the burner which, if successfully ignited, is thereafter increased 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 establishing combustion, then the full desired supply of fuel is established thereby making it possible to check the operation of the system without delivering a very large supply of fuel to the burner in the event ignition is not successful.

The inventionfurther includes the usual safety mechanism by which the system is rendered inoperative in case combustion is not successfully established and the arrangement is such that the large supply of fuel cannot be furnished to the burner before the safety mechanism has checked the operation of the apparatus.

In the specific embodiment of the invention herein disclosed, the *valve mechanism comprises a pair of valves one of which is preferably a low capacity valve and the other of which is preferably a high capacity valve. The low capacity valve is initially energized under the command of a main control device and, in the event the supply of fuel furnished by this low capacity valve is successfully ignited, then the high capacity valve is energized and the low capacity valve is deenergized. The ignition means for igniting the fuel supply to the burner is controlled simultaneously with the low capacity valve in the preferred form of the invention. Also, it is preferable to provide a burner motor which is energized the whole time that the system is in operation.

The system also is preferably arranged to give a recycle upon a failure of flame or momentary power failure.

Other objects of the invention will be found in the'drawing, the following description and in the appended claim.

For a better understanding of the invention, reference may be had to the following detailed vSimilarly, upon a room description and theaccompanying single drawing which is a diagrammatic showing of one form of the present invention.

Referring to the drawin 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 being such that valves l0 and I2 are moved to open position upon energization of their respective 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 supporting air 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 indicated 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 fixed 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 perature falls, contact blade I9 first engages a contact 2| and upon further perature contact blade fall in the room tem- 20 engages a contact 22. temperature rise, the contact blade 20 first disengages its contact 22 and 30 thereafter the contact blade l9 disengages its contact 2|.

The system further includes a thermal safety switch which comprises a switch 25 that is thermally operated and an electric heating element 26 for operating the same. Such thermally operable switches are well-known in the art and the thermal safety switch utilized in the present invention may well take the form shown in Frederick S. Denison application Ser. No. 226,395 which was filed October 15th, 1927.

The system of the present invention further includes a combustion responsive switching mechanism which preferably takes the form of a, slip friction stack switch generally indicated at 28. The stack switch 28 includes first cold and hot switches comprising contacts 29 and 30 and a switch arm 3| that is operated through suitable slip friction mechanism, the arrangement being such that switch arm 3| engages contact 29 in 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 encomprised by bustion. The stack switch 26 further includes second cold and hot switches comprised by a mercury switch 32 having a pair of cold electrodes 33 and a pair of hot electrodes 34 adapted to be bridged by a body of mercury 21. Stack switch mechanisms of this general character are wellknown in the art and the one diagrammatically illustrated herein may well take the general form shown in Figs. 2 and 3 of Frederick S. Denison application Ser. No. 697,687, filed 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 armature 31 when energized. An armature 31 controls switch arms 38, 39 and 46 to move the same into engagement with respective contacts 4|, 42 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 48 and a highvoltage primary 49 which is connected to line wires 45 and 46 by wires 56 and 5|.

The remaining circuit connections will be described under the heading Operation.

Operation With the parts in the position shown, the room temperature is above the desired value andthe relay coil 36 is deenergized. The cold switches comprising switch arm 3| and contact 29 and the electrodes 33 of mercury switch 32 are both closed and the combustion responsive hot switches arm 3| and contact 36 and the electrodes 34 of mercury switch 32 are both opened indicating that there has been a decrease in the temperature of combustion. Low and high capacity valves l6 and |2 are both closed and the ignition means |4 andburner 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 heating element 26 is established as follows: secondary 48, wire 55, safety switch 25, wire 56, contact 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 secondary 48. Energization of relay coil 36 moves switch arms 38, 39 and 46 into engagement with their respective contacts 4|, 42 and 43. Engagement of switch arm 39 with its contact 42 establishes 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 element 26, wire 66, wire 6|, relay coil 36 and wire 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 circuits 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,

cold electrodes 33 and the bridging mercury 21 of mercury switch 32 and wire 1| at which point the circuit branches, one part going by way of wire 12, ignition means l4 and wire 13 to line 46, whereas the other portion goes -by way of wire 14, electromagnetic winding H of low capacity valve l6, wire 15, and wire 16 to line 46.

In this manner, upon a call for heat by the room thermostat IS, the burner motor I5 is energized and a small supply of fuel is furnished to the burner which should be ignited by the ignition means l4. In the event ignition is not successfully established within a predetermined timed period, the heating element 26 will cause opening of safety switch 25 whereupon the system will be rendered inoperative until manual intervention. On the other hand, if combustion is successfully established within this period, switch arm 3| will move into engagement with contact 36 and thereafter will disengage contact 29. Likewise, mercury switch 32 will tilt to its opposite 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 relay coil 36 which maintaining circuit operatively deenergizes heating element 26 by establishing a shunt therearound. This maintainingcircuit 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 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. Movement of mercury switch 32 to its hot position 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 mercury switch 32 however establishes an energizing 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 capacity valve 12, wire 64, and wire 16 to line 46. The system is now in normal operation, combustion having been established and resulting in an increase in the supply of fuel.

When the room temperature begins to rise so as to move contact blade 26 from engagement with contact 22, relay coil 36 will be maintained energized either by the previously described holding circuit or by the maintaining circuit. However, when the room temperature rises sufliciently to additionally move contact blade l9 from engagement with contact 2|, then the maintaining circuit will be interrupted, as will be the holding'circuit if switch arm 3| has not as yet disengaged 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 contact blades I9 and 26 into engagement with their respective contacts 2| and 22 and until switch arm 3| disengages contact 36 and'engages contact 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 cannot be again energized upon resumption of power unless the stack temperature has decreased sufficiently to move switch arm 3| from' engagement with contact 30 and into engagement 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 flame during normal operation, switch arm 3| will first disengage contact 30 whereupon relay coil 36 will be deenergized after which, upon engagement of switch arm 3| with contact 29 and if the room thermostat switches are both closed, relay coil 36 and heating element 26 will again be energized to establish anew trial ignition period. If combustion is not successfully reestablished at this time the system will be rendered inoperative by the safety switch and remain so until manual intervention.

From the foregoing description, it will be observed that the present invention provides a trial ignition period in which a relatively small amount of fuel is supplied. If ignition is not established, the system is shut down without very much fuel having been delivered to the. burner or combustion chamber. In the event'combustion is successfully established, the supply of fuel is increased to the desired amount. In this manner, 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

It will also be noted that the invention provides all of the other usual features such as a recycle upon power failure or flame failure, together with control of the ignition means.

It will be apparent that many changes in the specific arrangement shown herein can be made by those skilled in the art and I therefore intend to be limited only by the scope of the appended claim.

I claim:

In combination, a room thermostat, a thermal safety switch including an electric heating element, a relay coil, a control switch and a load switch closed thereby when energized, first cold and hot combustion responsiveswitches overlappingly controlled upon a rise in the temperature of combustion, an energizing circuit for said relay coil and heating element in series including said room thermostat, safety switch and first cold combustion responsive switch, a holding circuit for said relay coil including said room thermostat, first 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 connections controlled by said load switch and secand cold switch for energizing said low capacity .valve and said ignition means, an energizing circuit for said burner motor controlled by said load switch, a high capacity fuel valve, and an energizing circuit therefor controlled by said load switch and said second hot switch. LESTER D. COI'EA.

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