US2616491A - Burner safety control system - Google Patents

Description

NOV. 4, 1952V H.` NYCUM BURNER SAFETY CONTROL SYSTEM Filed sept. 15, 1947 @L v lNvENToR /L/omer /yfz/#W Q l gATTORNEY Patented Nov. 4, 1952 UNITED STATES PATENT QF'FI'CE- BURNER- SAFETY CONTROL SYSTEM Homer C. Nycum, Kalamazoo, .Micl1;,.assignerto: The'l C. H. Dutton Company, Kalamazoo,.,Mich., a corporation ofMichigan llplication'september 15, 1947; Serial N o. 774;,161

` 18 Claims. 1,

inventionV relates to'improvementsin a burner' safety control' system;

The principalVV objects of this invention are:

First; to providea system of controls-for gas'- eous or liquid fuel burners particularly-'for boiler furnaces and the like' in which the burnercannot be startedV while there-is a dangerous accumulationy of fuel in thezfurnace;

Second, to providel a control system forv the burner element of a boiler in which an ignition means is actuated by cycling mechanism arranged to provide-a pre-ignition purging period to remove any accumulation of fuel. of? an explosive character from the furnaceV before applying the ignition.

Third, td provide a control systemv for" boiler burners and the like which is adaptable to various cycles of operation such as single ignition or automatic repeated ignitionA depending-upon the' desiredI method of" operating-the boiler.

Fourth, to provide control' circuits for" start'- ing and'igniting the burner mechanism of a boiler in .which manual operation of any of" theswitches intheA circuit cannot immediately apply ignition energy tothe burner but mustiirst'initiateaut A- matie cycling mechanism' which in turn will ig'- nite the burner.

Fifth, to provide a control circuit for a boiler or. the4 like in which an alarm7 or other device indicating, the necessity for manual'attention may bearranged. to. be. actuated under. a plurality of different. operating conditions depending.I upon the desired'cyo1eV of` operation of the boiler.r

Sixtihto. provide cyclically operating start-er mechanism for. a, burner arranged'A to require a complete purging cycle before it will apply ignition energy tov the burner so that if Ithe mechanism.is de-energized. during` its purging. 0r ignitionlperiods it will` have to returnto its starting positionbefore againbeing. effective to. start the burner.

Seventh, to provide electrically driven timed switching mechanismv for energizing the ignition element of a burner which mechanism is arranged toiautomatically return to its starting p0 f vantages of thevsy-stem will be apparentf from a consideration of theV following description and claims;

The drawing" illustratesv my control system as applied' to the burner and auxiliary elements of a boiler and isaschematic wiring diagramvof my control sys-tem with the boiler and its auxiliary elements illustrated conventionally.

The drawing illustrates a boiler furnace I provided-with a'burner 2` andar smoke iiuev3'. The flue 3 is provided with an exhaust fan driven by a motor indicated at 4- for inducing a draft through the flue and the-burner isv provided with a motorindicated at 5^. The boiler is provided with a water level gage' and a high pressure device` 1 for indicating dangerously low water level and dangerously high steam pressure respectively. The water gage' is provided with an arm for opening the-electrical contacts -8-and`the presr surey device 'lis arranged to open thecontacts S when' the pressure rises too high; The burner 2 `is arranged to be supplied with liquid'or gaseous fuel through the pipel IIl and theadmission of fuel' isl controlled by the solenoid operated valve indicated at II'. An ignition device such as a transformerk and a spark gap for igniting the fuel is indicated conventionally at I2; The furnacer is provided with a device for indicating the presence of the ilamein theV furnace. In the example illustrated this' takes the form of a bi metallicelementl I3 extending into the flue 3 and arranged to* close thev electrical contacts- I4' upon the establishment of a' flame in thefurnace. Similar devices such as optically operated switches' responsiveY to the main flame ofthe burner could be' substituted for the bimetallic elementA I3v and switch I4.

Thev eiementsthus far described are operated from* a-sourceof electrical energy indicated at l5 andare" controlled by a main circuitswitch |26. A shutdown switchV I1 is providedin one side ofthe power source for manually shutting down the operation of the boiler and its auxiliary elements. 1t will be noted that the pressure contacts 9 and water level contacts 8 are connected in series in one side of the power source and that the motor 4 for operating the draft fan is connected directly across the power source so as to be actuated immediately upon closing of the switches B, yi), It, and I l. For convenience in desscribing the controlV circuit' and mechanism all of the elements circuits toy the live side of the line which" is the 3 side controlled by the shut down switch |1. The system is shown in cold, shut down condition My control mechanism comprises four solenoid operated switches having solenoid coils labeled A, B, C and T and a preignition timer labeled PT and an ignition timer labeled IT. The solenoid A and its associated switches may be referred to as a starting relay. The solenoid B and its associated switches may be referred to as a cut-out relay. The solenoid T and its associated switches may be referred to as a transfer relay. A manually controlled double pole switch for selecting the operating cycle of the system is indicated at I8 and an alarm bell for indicating the need of manual attention of the system is indicated at I9.

The burner motor is connected from the dead side of the line through a conductor 29 t0 a pair of terminals 2| positioned on either side of a contact carried on one arm of the relay T. In the de-energized position of the relay T as illustrated in the diagram, the terminals lI are connected to a conductor 22 extending to a conductor 23 having a terminal 24 which is connected to the conductor 25 by one contact of the relay B. The conductor 25 extends to one terminal 26 connected by a contact of the relay A to the live side of the power source. It will thus be seen that upon closing the switches i3 and I1 with the pressure contacts 9 and water level contacts 8 closed as shown the burner motor 5 will immediately be energized through the conductors and terminals thus described.

The preignition timer labeled PT consists of a gear driven disk 21 carrying a weighted lug 28 arranged to be rotated upwardly to close the preignition contacts 29. The disk 21 is gravity operated to automatically return to the unactivated position shown upon de-energizing of the preignition timer motor indicated at 39. The ignition timer labeled IT is of similar construction having a gear driven disk 3| and weighted lug 32 arranged to be rotated to close the ignition timer contacts 33. The ignition timer is driven by the electric motor 34. It will be understood that the preignition timer and ignition timer may be selectively adjusted so that the period beween energiaation of either of the motors 30 or 34 and closing of the contacts 29 and 33 respectively may he set for any desired interval.

The motor for operating the preignition timer is connected from the dead side of the power source through a conductor 35 to the conductor 23 and from there to the live side of the line through the same circuit which energizes the burner motor 5. It will thus be seen that when the switches I5 and |1 are closed both the burner motor and preignition timer motor will begin to operate and that after a predetermined lapse of time the weighted lug 2B will close the preignition timer contacts 29 and hold the contacts closed so long as the preignition timer motor 39 is energized.

The first consequence of closing the contacts 29 is to apply electric energy to the ignition device |2 by connecting the conductor 36 through the contacts 29`to one branch of the live side of the power source indicated at 31. Simultaneously with energizaticn of the ignition device l2 the solenoid operated valve controlling thew admission of fuel to the burner is energized from the dead side of the line through the conductor 38 and the terminals 39 closed by one arm of the relay T and the conductor 49 to the previously described conductor 3B. Thus fuel and igniting 4 energy are supplied to the burner and a llame should be established in the furnace Note that the fan motor 4 has been energized during this preignition period and will have purged the boiler and flue of dangerous accumulations of fuel and gases.

A second consequence of the closing of the preignition timer contacts 29 is to connect the solenoid of relay C across the power source. The circuit for energizing the solenoid of relay C extends from a branch of the dead side of the power source indicated at 4| through the solenoid and a conductor 42 closed by one contact 43 of the relay A. The circuit is returned through the conductor 44 to the terminals 45 connected by one contact of the relay C and from there Athrough the conductor 43 to the conductor 36 which has previously been described as energized by closing of the preignition timer contacts 29.

Energization of the relay C as just described causes the switch arm 41 to be drawn toward the solenoid connecting the terminals 48 which will establish a holding circuit from the conductor 44 to the conductor 49 connected to the live side of the power source through the normally closed push button switch 50. The relay C is thus sealed to the live side of the line and maintained in energized condition. Energizing of the relay also connects the terminals 5| which establish a circuit from the dead side of the power source through the ignition timer motor 34 and conductor 52 to the terminals 24 on the relay B. As was previously described the terminals 24 are connected through the terminals 26 to the live side of the power source so that the ignition timer motor 34 commences to operate and after the pre-determined operating period will close the ignition timer contacts 33.

With the manually operated cycle selecting switch I8 in open position as shown, closing of the contacts 33 will connect the live branch 31 of the power source through the conductor 53 to the terminals 54 which are connected by one contact of the relay A in de-energized condition of that relay. The terminals 54 are connected through the conductor 55 to the terminals 56 closed by one contact of the relay T in the deenergized condition of the relay T. One of the terminals 56 is connected to a conductor 51, one branch 58 of which extends to the bell I9. The other branch 59 of the conductor 51 extends to the solenoid of the relay B. It will thus be seen that if the relay T remains in the de-energized condition illustrated, after the closing of the preignition timer contacts 29 and ignition timer contacts 33, circuits will be established through the terminals 54 and 56 to energize the alarm bell 9 and the relay B. This condition will exist if no flame has been established in the furnace to close the llame operated contacts |4 and energize the solenoid of the relay T through. the conductor 60.

The immediate consequence of energizing the relay B as just described is to open the terminals 24 and close the terminals 6|. Opening of the terminals 24 breaks the previously described circuits to the burner motor 5, preignition timer motor 39 and ignition timer motor 34 so that these motors are de-energized. The gravity operated disks 21 and 3| immediately open the contacts 29 and 33 thus de-energizing the ignition device I2 and the solenoid valve il to cut olf the supply of fuel to the burner. Opening of the ignition timer contacts 33 also breaks the circuit through which the solenoid of relay B was originallyenergized butzit'will :beznotedthatithe closing. of,lv the?,V terminals? BIiI by" the: relay B1' establishes a circuit.' fromf. the livel conductorv 432 through the terminals` 54"r ofrrel-ay A, ,conductor4 5'5 and.; terminalsf.` 56tof relay. 'ntoiithe'aconductor 59 and; solernoidiof; rela-yBto'. hold thefrelaysB ini energized position;

With.: the. system? in` the:- conditionv. thus de'.- scribed an attempt has beenimade toi establish: a amerin-.thei-boilerand this attempt .having failed, theA burner: motorV is.` deenerigize'df. by: the: opening: of: the: terminalsrzdi oil relay B.. The; solenoid fuel; valve and ignition device. are:- de-energized and. ther preignition f and ignition timer..` motors arev cle-energized.. The alarm bell is energized indicating the needlfo'r manual. attention of; the system:v 'llhel operator-v may then. operate. the manual:controlbutton 50T which breaks` the con:- nection to. the. live branch 495` de-energizin'g. the live'side: of terminals 48 and. 6 I.. Thisf de-energizesthe; alarmabell;` the relay Co. andthe relay `BV se thatlthe circuit' rie/assumes* the# position illustratedlin Fig; 1'. If the shutdown switchhas remained closed throughout the initialignitionattempt, the system willagain proceed through the previously described cycle applying iirst, apurging periodasdeterminedlby the preignition timer during. which. any accumulation. of fuel in the boiler.` or 'flue isrremovedf by the fan` 4f prior to the energization of the ignition device I2.

Assuming thatr upon the closing of? the preignition timerl contactsI 29? and the establishing of the ignition circuit as previously described that-the flame is-properly lighted in theA furnace, the' bimetal element I3' will be heatedfand' close the' lam'e operatedcontacts Miprior tothe closing otthe contacts-33 by the ignitionltimer ITjit'being the 'function ofthe ignition timerl to establish and limiti the' periodi of time duringr which fuel and ignition may besuppl'i'ed totheburner without the establishmento'f a flame. Aspreviously described the'solenoidof'ithe'v relay T will then be 4energized through theA conductor 5l!t and' the relay` will 1 be operated fromn the"v de'-energized position shown in' 1. The rst consequency'offoperation` of the'relay T is" to corrriect'thei` conductor 38' from theV solenoidy operated: fuel valve I I through' the terminals 52 totheconductor't; contacts I'4and the live sideof thepower source to hold thesolenoidoperated fuelvalvein open energized posimotor 5l Opening ofthe terminalsle'by therelay T will break the' connection between the alarm bell I9 and relay B to. thealive side of.' the line preventing these elements from being energized so long astthe relay T isenergized. The terminals 63'V of the relay T will be closed and connect the relay A through, the conductor 64 to the conductor 65. and the terminals 66 of therelay Af..

The previously described operations having taken place practically instantaneously, the-subsequent. closing of the ignition timer contacts 33- will establish a circuitirom. the live branch 31 ofthe:y power source through` ther conductor 53 to the 1 conductor" 65, .terminals 63. and; conductor 64 to energize the relay A. instead. of the relay B whose circuithas been broken'at the-.terminalsi aspreviou'sly described. Energization ofthe relay twill-immediately closethe terminas B so that the relay' A- issealed tothe live side of the line through the branch conductor. 49 and push vbutton 6 switch 5'0:l and: so thattherterminals. 26, 54,. and-A43 arel all :op cned'.

Opening oithetterminals 26:breaks the; circuit to the preignitiontimerimotor. 'and. ignition timermoto'r. 3'4"which: immediately open the' contacts ziszland 331 respectively. Opening. of.' theA terminals 431` breaks thel circuit to the relay C and returnsthat relay to its dce-energized position illustratediin Fig-.11'. The system thencomes to rest inoperatingicondition with vthe burner motorxand fuel-.valve venergized .through the relay T and name controlled contacts I4 directly to thev live si'de` of the line;V The ignition device, alarmbelljpre'- ignition` timer motor:y and.v ignition timer motor are alldeenergized asare the relays B and C and the burner will continue to operate so long as the pressure contactsag, water: leverrcontact's ,8,- shut downswitch IT and' main switch I5' are closed',

Assuming now that the live. sidetof the.r power sourceis: broken either by intentional shut down ofi the switch ISI or normal operation of; the pressure switch 'I or: abnormal operation.of'waterlevel contacts 8, orJby external power failure, the entire control circuitwillbe de-energized and assume the'position illustrated in the diagram from lwhich positionv the system will automatically. proceed through alighting cycle as irst described upon theY closing of. the switch which originally broke the circuit, Ifl everything functionsA correctly, therame willfbe rei-established in the furnace withoutmanual attention and without sounding the: alarm bell.. If, however, therrelight attempt is notsuccessfil, the control circuits` willestablish the alarm and condition themselves,` for manual operation of the relight button 5i);`

From. any shut down condition' ofA thev system, ignition energy cannot. be supplied. to the ignition device |12 withoutthe fan motor 4 operating: through. the predetermined' purgev period as establishedbythe preignition` timer` PT and contacts29: It .will thus be seen thatmy control circuitwill automatically. relight a boiler burner under normal operating conditions as when the pressure' in the boilerrises too high through light loa'dconditions or as whenthe shut down switch II` i's-operated at theend and' start of a work day; Similarly, the burner willbe automatically relighted after' correction of. abnormal power failurev or.' low water level-conditions. The system willi require no manual attention so long as tlie'fauxiliary elements: ofthe boiler are functioning properly; However, ifsome element fails to function properly and a-flameV is not established my circuit will disconnect the fuel' and ignition sources-from the burner and actuate thealarm belli indicating ltlie need for: manual attention.

Considering now'the operation of' the control circuit shownY in the diagramfwith the switch I'Sfl inc'losed` position, crmductorsV 53, 55; 6l!) and Erfare all electrically connected andr functionv as al single. conductor; With the variousl automatic switches in. thep'o'sitions shown and upon closinglofrthe powerv switches I and'. IT, the fan mo;- tor 4&1 and burner. motorV 5 and preignitionv timer motor 3.0: will be energized. in the samev manner as .previously described applying apurging'period to' the boilerwhile the preigni'tionztimer'moves to cl'lise-thel contacts Z9. Closing ot the contacts 29 will.` apply energyv to thelignition device I2, fuel valve II: and relay C` as previously describedl and the: relay C will be energizedzto' close' thel termi'- nals .485 andy E I Closing of the terminals- 481 will transfer; the relay C' to the live side line: at 49 and closingoffthe terminals 5I will apply energy tothe ignition, timer motor 34; asf previouslyde.-

scribed. During the period of operation of the ignition timer motor 34, a flame should be established at the burner 2 and close the name operated contacts I4 to energize relay T.

Assuming now the situation when no iiame is established prior to closing of the ignition timer contact 33. When these contacts are closed a circuit will be established through the branch 31 of the live side of the line, contacts 33, conductor 53, switch I8, terminals 56 and conductors 51 and 58 to alarm bell I9 and relay B immediately indicating the failure of the burner to light. Simultaneously a circuit will be established from the switch I8 through the conductor 64 to the relay A energizing the relay from the position illustrated to open the terminals 25, 43, and 54 and close the terminals 66. Closing of the terminals 6=6 will connect the branch 49 of the live side of the line through the push button switch 50 to the conductors 65, 53, and switch I8. Opening of the terminals 2-6 will break the circuit to the ignition timer motor 34 and preignition timer motor 3U which will immediately open the contacts 29 and 33. Opening of the terminals 43 de-energizes the relay C so that it returns its switch to the position illustrated in Fig. 1 further breaking the circuit to the ignition timer motor 34. Closing of the terminals 65 will establish a holding circuit for the relay A through the conductors 53, switch I8 and conductor 64 to hold the relay in an energized position. Relay B is energized through 59, terminals 56 and switch I8. The system then comes to rest with the relays C and T de-energized and with the burner motor 5, ignition device I2, fuel valve II, pre-ignition timer and ignition timer de-energized. The fan will continue to operate so long as the pressure switch and water lever switch are closed and the alarm bell will be actuated through the terminals 56, switch I8, conductor 53 and terminals 65.

The operator may then manually open the push button switch 50 breaking the circuit to the branch 49 of the live side of the line so that the holding circuit for the alarm bell and relays A and B are broken silencing the bell and returning the relays A and B to the position illustrated in Fig. l. If the shut down switch, pressure switch and water level switch remain closed, the control system will immediately start a succeeding lighting cycle as previously described.

If the lighting or relighting attempt is successful between the closing of the preignition contacts 29 and the ignition timer contacts 33, the flame control contacts I4 will be closed energizing the relay T and moving the switches operated by it from the position shown in Fig. 1. When the ignition timer contacts 33 are closed subsequent to operation of the relay T, a circuit will be completed from the branch 31 to the live side of the line through the contacts 33, switch I8 and the conductor 64 to the relay A. Energization of the relay A is thus effected initially through the ignition timer contact 33 and held through the terminals 33 and 65 upon movement of the switch arm from the position illustrated.

Opening of the terminals 43 by the relay A will de-energize the switch C to open the terminals I and de-energize the ignition timer motor 34 and open the ignition timer contacts 33. Opening of the terminals 23 by the relay A will break the circuit to the preignition timer motor 33 and open the contacts 29. Closing of the terminals 62 by the relay T will establish a running circuit for the fuel valve II and the terminals 2I will transfer the burner motor 5 directly to the live side of the line and the system will come to rest with the burner operating and with the relays A and T energized and B and C de-energized.

Normal shut down of the system by opening of any of the primary switches 8, 9, I6 or II will immediately de-energize all switches and relays and cause them to assume the position illustrated and re-closing of the switches will automatically commence a relight cycle.

Abnormal failure of the flame which opens the name control switch I4 will de-energize the relay T opening the running terminals 62 to the fuel valve I I and the terminals 2| to the burner motor 5. De-energization of the relay T will close the terminals 56 energizing the bell I9 and relay B. Relay A will remain energized through the terminals 66, conductors 53, switch I 8 and conductor Eli. Terminals 26 which energize the preignition timer motor 33 and the ignition timer 34 will therefore remain open and the system will come to rest with relays A and B energized and relays T and C (ie-energized. The bell will continue to sound indicating the need of manual attention of the system.

After a flame failure as just described the operator may open the manual push button 50 breaking the connection to the branch 49 of the live side of the line and to the terminals 66. This action will (ie-energize the relays A and B and silence the bell leaving all switches and relays rie-energized and ready to automatically commence a relight cycle as described above if the primary controls and switches are closed.

From the foregoing descriptions of the system it will be apparent that the system will automatically start a lighting cycle upon closing of the primary switches IB, I'I, 8 and 9 and will sound the alarm I9 if the lighting attempt is a failure whether or not the switch I8 is open. The difference in operation of the system with the switch I8 open or closed results when the flame fails for some reason other than the operation of the primary switches such as a fuel failure or clogging of the burner mechanism or failure of the burner motor 5. With the switch I8 open the system will automatically make one relight attempt without sounding the alarm and if the relighting attempt is successful no manual attention is required. However, with the switch IS closed and upon failure of the flame for some abnormal reason the system will cle-energize the motor, fuel valve and ignition and sound the alarm to call the attention to the failure of the name. No preferred form of the system is advocated as it is largely a matter of the desire of the user as to which manner of operating his boiler is most advantageous to him.

It should be evident to persons skilled in the art that various modications of the above described circuit will be possibly depending upon the degree of automatic control and type of operation desired. Thus the circuit for energizing the fan motor Il could be carried through terminals arranged to be opened by energization of the relay B so that upon failure of the flame heat would be retained in the furnace instead of being exhausted through the flue 3. Other controls or auxiliary elements of the boiler and furnace may be added as desired such as additional fuel valves where the burner is arranged to use heavy oil mixed with light or gaseous fuel for igniting purposes. The circuit illustrated and described is intended to be an example only of the operation of my control system with the contacts S, il and II representing a class of primary controls which are `more or less normal Vto the operation of most boilers.

I have thus described a highly practical form of my control circuit which is adaptable in various forms to boilers generally. The several solenoid switches and timer switches are commercial-ly available so that the system may be assembled at a minimum of expense and without special parts.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. Cycling mechanism for obtaining a purging period and ignition period in a burner control system comprising a pair or control switches biased to open position, electrically operated time delay means for successively closing said switches and holding them closed only so long as said means are energized, a circuit for-energizing said means-including a solenoid operated switch, a second energizing circuit for energizing the solenoid of said solenoid operated switch to control said iiirst energizing circuit and including a second solenoid operated switch and the'seco-nd of said pair offswitches, a third energizing circuit forenergizingsaid second solenoid switch including a switch responsive to the existence of a'flame at said burner, and an electrically operated ignition device connected vto be energized by closing of therst of said control switches.

`2. Control mechanism for the burner of a furnace comprising an electrically operated ignition device for igniting said burner, an ignition switch connected in series with said ignition device and biased to open position, a motor driven device arranged to effect the closing of said ignition switch after a predeterminedpurging rperiod following the energization of the motor of said Adevice, a circuit for energizing said motor driven device, a solenoid operated switch in lsaid last mentioned circuit and arranged to de-energize said motor driven device after a predetermined period of operation of said device, said device being biased to immediately return to its start-v ing position whenever the motor lthereof is vdeenergized, and a time delay switching device connected tobe actuated by the closing of said ignition switch, the switch of said time delaying device being connected to energize the 'solenoid of said solenoid operated switch.

3, Control apparatus for vthe burner of -a boiler furnace comprising', a primary control element for indicating a functional condition of said boiler, a switch operated VVby said element' and connected xto de-encrgize the remainder of said apparatus upon the establishment of an undesirable condition in said boiler, -atransfer-relay, an ene-rgizing circuit for said transfer relay-including Va switch closed upon'the establishment of a vflame in said burner, :an electrically operated fuel valve for said burner, a running circuit for said fuel valve having contacts closed by said'transfer re lay in the energized position thereof, annelectrically operated ignition device AVfor said-burnen'a circuit for energizing said ignition device lincluding an ignition switch, a starting c'ircuit'for said fuel valve `connectedby said transfer i'elaylin the cle-energized position thereof to said ignition circuit to be .energized `from saidignition circuit, a

motor'for said burner having a running circuit energized by a contact closed in the energized posii tio-n of said transfer relay, electrically operated timedr mechanism-for closing sai-d ignition switch,

said mechanism bei-ng biased toignition switchv opening position, a circuit -for energizing v'said mechanism including a pairof switches connected in series, a starting circuit for said burner motor connected to said circuit for energizing said mechanism by said transfer relay in the de-energized position thereof to be energized with said mechanism, a starting relay having a contact arranged to close one of said pair of switches inthe dre-.energized position of said starting relay, a common conductor, an energizing circuit for said starting relay including a switch closed by said transfer relay in the energized position thereof and connected to said common conductor, a cutout relay having a contact arranged to close the other of said pair of switches in the de-energized position of said cut-out relay, an energizing circuit for said cut-out relay including a switch closed by said transfer relay in the de-energized position thereof and a switch closed by said starting relay inthe cle-energized position thereof and connected to said common conductor, a time limit switch connected to said common conductor and adapted when closed to energize the same, a second electrically operated timed mechanism for closing said time limitl switch, said second mechanism being biased to limit switch opening position, a circuit for energizing said second mechanism connected t-o said circuit for energizing said iirst mechanism so as to be deenergiized therewith, a third relay having a contact arranged to break said energizing circuit for said second lmechanism in the de-energized position of said third relay, an initial energizing circuit for said third relay including a contact closed in the de-energlzed position of said starting'relay and a conta-ct closed in the cle-energized position of said third relay, sai-d last mentioned contact being connected to said ignition circuit for energization therewith, a self-operated holding contact on said third relay closed in the energized position thereof and connected to said circuit for energizing said third relay to energize the same after initial energization by saldignition circuit, a holding contact closed by said starting relay in the energized position thereof and connected to said common conductor, a third holding cont-act closed in the energized position of said cut-out relay and connected to said common conduct-or, a; manually controllable switch for cle-energizing the circuits through said holding contacts, and a selectively operable element for shunting said switch closed by said transfer relay in said energizing circuit of said starting relay to sai-dcommon conductor and for shunting said contact closed by said starting relay in said energizing circuit for said cut-out relay to said common conductor, said furnace having a gas purging element electrically connected to be energized whenever said apparatus is energized.

4i Control apparatus for the burner of a boiler furnacev comprising, a primary control element for indicating a functional condition 4of the boiler of said furnace, `a switch operated by said element and connected to ole-energize th-e remain- -der ofA said apparatus upon the establishment of an undesirable condition in said boiler, la transfer relay, an energizing circuit for said transfer relay' including a switch respons-ive to the establishment of-a frame in said'burner, an electrically operated fuel valve for said burn-er, a running circuit for said fuel valve having contacts closed by said transfer relay in the flame operatngpositi-on thereof,v an electrically operated Aignition devi-ce `for ysaid burner, a circuit f-or energizing said ignition deviceincluding an ignition switch, a starting circuit for said fuel valve electrically connected to said ignition circuit by a contact on said transfer rel-ay in the no :dame position of said transfer relay, a motor for said burner having a running circuit energized through a contact closed in the flame operating position of said transfer relay, electrically operated timed mechanism for closing said ignition switch, said mechanism being biased to ignition switch opening position, a circuit for 'energizing said mechanism including a pair of switches connected in series, a starting circuit for said burner motor electrically connected to `said circuit for energizing said mechanism by a contact of said transfer relay in the no flame position thereof, a starting relay having a contact :arranged to close one of said pair of switches in the de-energized position of said starting rel-ay, fa common conductor, an energizing circuit for said starting relay including a contact closed by said transfer relay in the name operating position thereof and connected to said common conductor, a cut-out relay having a contact :arranged to close the other of said pair of switches in the de-energized position of said -cut-out relay, `an energizing circuit for said cut-out yrelay including in series a contact closed by said transfer relay in `the no flame position thereof 'and a contact closed by said starting relay in the `die-energized position thereof and said common conductor, a signal `device connected in parallel with said cut-out relay to be energized therewith, a time limit switch connected to said common conductor and adapted to energize the same, a second electrically operated timed mechanism for closing said time limit switch, said second mechanism being biased to limit switch opening position, Ia circuit for energizing said second mechanism connected to be energized and de-energized concurrently upon the lclosing ya-nd opening of said ignition switch, a holding contact closed by said starting relay in the energized position thereof and connected to said common conductor, a second holding contact closed in the energized position of said cut-out relay and connected to said common conductor, and a m-anually controllable -switch for de-energizing the circuits through said holding contacts, said furnace having .a purging `element electrically connected to be energized whenever sai-d first mechanism for closing said ignition -switch is energized.

5. Control apparatus for the burner of a boiler furnace comprising, an electrically operated fuel valve for said burner, la -transfer relay, an energizing circuit for said transfer relay including a switch responsive 4to the establish-ment of a flame in said burner, an electrically operated ignition device for said burner, a circuit for energizing said ignition device including an ignition switch, a circuit for energizing said fuel valve connected to said ignition circuit by a contact on said transfer relay in the no flame position of said transfer relay, a mot-or for said burner having a running circuit energized by a contact closed in the flame oper-ating position of said transfer relay, electrically operated timed mechanism for closing said ignition switch, said mechanism being biased to ignition switch opening position, a circuit for energizing said mechanism including a pair of switches connected in series, a starting circuit f-or said burner mot-or connected to said circuit for energizing said mechanism by a contact on said transfer rel-ay in the no ame position thereof, a starting relay having a contact arranged to close one of said pair of switches in the de-energized position of said starting relay, a comm-on conductor, an energizing circuit for said sta-rting relay including a contact closed by said transfer relay in flame operating position of said transfer relay and connected to said common conductor, la cut-out relay having a contact arranged to close the other of said pair of switches in the yde-energ-ized position of said cutout relay, an energizing circuit for said cut-out relay including in series .a switch closed by said |transfer relay in the no flame position thereof and a VContact closed by said starting relay in the de-energized position thereof and said common conductor, a signal device connected in parallel with said cut-out relay to be energized therewith, a time limit switch connected to said com-mon conductor and adapted to energize the same, a second electrically operated timed mechanism for closing said time limit switch, said second mechanism being biased to limit switch opening position, a circuit for energizing said second mechanism connected to be energized concurrently with the closing of said ignition switch and to be de-energized concurrently with said circuit for energizing said first mechanism, a holding contact closed by said starting relay in the energized position thereof and connected to said common conductor, a second holding contact closed in the energ-ized position of said cut-out relay and connected to said common conductor, and a manually controllable switch for de-energizing said holding contacts, and a selectively operable element for shunting said switch in said circuit for energizing said starting relay land for shunting said switch in said circuit for energizing said cutout relay and operated by said starting relay.

6. Control apparatus for the burner of a furnace, said burner having an electrically operated auxiliary element coacting with the burner in sustaining combustion, comprising, electrically driven timed switching mechanism having an energizing circuit, a transfer relay, an energizing circuit for said transfer relay including a switch responsive to the establishment of a fiame in said burner, a running circuit for said auxiliary element having contacts closed by said transfer relay in the ame operating position thereof, an electrically operated ignition device for said burner, a circuit for energizing said ignition device including a contact closed by said mechanism, a starting circuit for said auxiliary element connected to be energized from said ignition circuit by a contact closed in the no flame position of said transfer relay, a starting relay having a contact arranged to break the energizing circuit to said mechanism in the energized position of said starting relay, a circuit for energizing said starting relay including a switch closed in the flame operating position of said transfer relay and a common conductor, a cut-out relay having a contact arranged to break said circuit for energizing said mechanism in the energized position of said cut-out relay, a circuit for energizing said cutout relay including in series a switch closed in the no flame position of said transfer relay and said common conductor, a second electrically driven timed switching mechanism having an energizing circuit and having a switch operative when closed to energize said circuit for energizing said cut-out relay, said second mechanism being arranged to be energized by closing of said contact closed by said first mechanism, a holding contact closed in the energized position of said starting relay and connected to said common conductor, a second holding contact closed in the energized position of said cut-out relay `and connected to said common conductor, and a manually controllable switch for de-energizingthe c ircuits through said holding contacts.

-7.- C ontro1 mechanism for a burner comprising, an electrically vdriven timed switching device Ahaving .an energizing circuit, a transfer relay including a switch responsive to the establishment of aflameinsaid burner, an electrically operated ignition element for said burner, ya `cir-- cnitiorenergizing said ignition element including 1.a contact closed by said device and arranged to be l open during the first .portion of the .cycle Qfgsaid device, a solenoid opened valve for supnlyingfuel .to 4said burner, a circuit for energizing the solenoid of said valve .and having a running contact closed by said .transfer relay in the flame Qperatingposition thereof, a starting relayhaving :a contact arranged to break .the circuit .for energizingsaid device .in the energized position f said starting relay, a circuit for energizing ASaid starting lrelay .including a switch closed in the .flame operating position of said transfer relay. a cutout relay having another contact arranged to .break said energizing circuit to .said devicein the :energized position of said cut-cut relay, a circuit for energizingsaid cut-out relay includinga switch closed `by said transfer relay in .the .n o flame position thereof, an alarm device -connected to be energized with said cut-out relay, and an electrically driven time delay switch mechanismarranged to close a switch toapply energy to said circuits .energizing said starting relay and ,said cut-.out relay, said time relay mechanism being connected to be energized by closing of said .contact Vclosed by said timed switching device.

:18. Control mechanism for a burner having a motor comprising, an v electrically driven timed switching device having an energizing circuit,ya transfer'relay, an energizing circuit for said transfer relay including a switch responsive to the establishment of a flame in'said burner, a circuit. for said motor and having a running .contact closedby'said transfer relay in the flame operating position thereof, an electrically operated ignition element for said burner, a cir.- cuit '.forenergizing saidv ignition element including a. contact closedfby said device andarranged to "ibe open during the first portion of the cycle of `said device, a solenoid vcontrolled valve for supplying fuel to said burner, a circuit for energizing said solenoid to open valve andhaving a running contact closed by said transfer relay inthe flame operating position thereof, a starter circuit'for said motor connected to said circuit for-energizing said device in the no-iiame position of said transfer relay by a contact thereon, a starting 4relay having a contact closed in the deenergized position of said starting relay and arranged to energize said energizing circuit to said device, `a circuit for energizing said starting -relay including a switch closed in the liarym operating position of said transfer relay.

9. Control mechanism for the burner cf a furnace comprising, a Imotor driven time delay switching device having an energizing circuit for themotor thereof, a transfer relay, an energizing circuit vfor said transfer relay including a switch responsive to the establishment of a flame in said burner, a motor for said burner having an energizing contact closed by said transfer relay inthe ila-me operating position thereof, an electricallyoperated ignition element for-said burner, a-circuitffor energizingsaid ignition element including a contact closed by said device and arranged to be open vduringthe first portion of the cycle of said -device, asolenoid Operated control valve for supplying fuel to said burner, .a circuit f Or energizing .the solenoid to vopen,s aidfvalve and having a running contact closed by said transfer relay in the flame .operating position thereof .and a starting contact .Connected tosaid ignition device by .said transfer relay in :theino flame ,position thereof, a starter circuit for .said burner :motor Connected by :a contact cn said transfer relay to `said .device energizing circuit in the no flame positionofzsaicl transfer relay, a .startingfrelay having .a switch in .said .energizing circuit to .said ,device `and closed .the cle-.energized vposition .of isaid starting relay, :a circuit for energizing said starting relay vincluding .a Vswitch. operated by said .transfer relay .and closed in the'fiaine ,operating-position thereof-a motor driven ,timed .cut-.out device having an energizing .circuit for the :motor thereof and a cut-.out switch biased .to open'position, xa cut-out relay .having an energizing .circuit connected vto be .energized-:byxsaid :cut-outswitch .and .having a Contactin-.circuit ,to .open said energizing circuit tosaid delay switching device when said cut-Gilt relay isenergized, said circuit .for lenergizing the motor .of said cut-out .device being connected through .said first. energizing circuit forsaid'time delay .switching .device .to lbe .de-energized therewith.

:10. .Control apparatus `for the :burner of Y a fur.- nace comprising, electricallydriven time delay switching vmechanism 'having an energizing cir.- cuit and .ignition switch, :a transfer relay, an energizing circuit for said transfer relay including .a lswitch vresponsive to the establishment of a flame in said burner, a power circuit for-said burner and .having .a running contact closed :by said transfer relay in the flame operating position thereof, an electrically .operated .ignition device forsaid burner, acircuit forenergizingsaid ignition device including said ignition switch and arranged to .be open during the first portioncf the cycle of said mechanism, aisolenoid control valvev for supplying fuel to said burner, a circuit for venergizing the solenoid to open said valve and havinga runningcontactgclosed .by said transfer relay in the flame operating position thereof, .a starting circuit for the solenoid of said valve connected to said ignition circuit by said transfer relay in the no flame position thereof, a starting relay .having a contact to break the energizing circuit to `s aid mechanismin the energized position of said starting relay, a circuit for energizing said starting relayincluding a switch closed by said transfer relay in the flame operating position thereof, a cut-out relay having a contact arranged to breaksaid energizing circuit to said mechanism in the energized position of said cutout relay, a circuit for energizing said cut-out relay including a switch closed in the no fla-me position of said transfer relay, a manually operable element for shorting out said switches in said circuits for energizing said `starting relay and said cut-out relay, an alarm device connected to said circuit for energizing said cut-out relay, said time delay switching mechanism being biased to move to open position when de-energzed, and a second time delay switching mechanism connected to be actuated by closing of said ignition switch and arranged to energize said either of said circuits for energizing said starting and cut-out relays depending on the position of said transfer relay.

11. Control mechanism for the burner of afurnace comprising, a time delay switching device having an energizing circuit and an ignition switch, a transfer relay, an energizing circuit for said transfer relay including a switch responsive to the establishment of a flame in said burner, a motor for said burner and having a running contact closed by said transfer relay in one position thereof, an electrically operated ignition element for said burner, a circuit for said ignition element including said ignition switch and arranged to be open during the first portion of the cycle of said device, a solenoid controlled valve for supplying fuel to said burner, a circuit for energizing the solenoid of said valve and having a running contact closed by said transfer relay in said one position thereof and a starting contact connected to said ignition device by said transfer relay in the other position thereof, a starter circuit for said burner motor connected to Said energizing circuit of said device by said transfer relay in said other position thereof, a starting relay having a contact in series in energizing circuit to said device and closed in the de-energized position of said starting relay, a circuit for energizing said starting relay including a switch closed by said transfer relay in said one position thereof, a motor driven timed cut-out device having a cut-out switch, a cut-out relay having an energizing circuit connected to be energized by said cut-out switch and having a contact in series in said energizing circuit to said delay switching device to open said circuit when said cut-out relay is energized, and a circuit for energizing said cut-out device and connected through said circuit for energizing said delay switching device to be de-energized therewith.

l2. Control apparatus for the burner of a furnace comprising, electrically driven time delay switching mechanism having an energizing circuit and an ignition switch, a transfer relay, an energizing circuit for said transfer relay including a switch responsive to the establishment of a flame in said burner, an energizing circuit for said burner and having a running contact operated by said transfer relay, an electrically operated ignition device for said burner, a circuit for said ignition device including said ignition switch and arranged to be open during the first portion of the cycle of said mechanism, a starting circuit for said burner connected by said transfer relay to said energizing circuit for said mechanism in one position of said transfer relay, a starting relay having a contact in series with the energizing circuit to said mechanism, a circuit for energizing said starting relay including a switch closed by said transfer relay in a second position thereof, a cut-out relay having a cut-out contact in series in said energizing circuit to said mechanism, a circuit for energizing said cut-out relay to open said cut-out contact including a switch closed by said transfer relay in said one position of said transfer relay, timed switch means for energizing said circuits to said starting and said cut-out relays at a predetermined time after the closing of said ignition switch, and a manually operable element for snorting out said switch in said circuit for energizing said starting relay.

i3. Control apparatus for the burner of a furnace having electrically operated auxiliary elements coacting to sustain combustion, said apparatus comprising, electrically driven timed switching mechanism having an energizing circuit and an ignition switch, a transfer relay, an energizing circuit for said transfer relay including a switch responsive to the establishment of a flame in said burner, running circuits for said auxiliary elements having contacts closed by said transfer relay in its flame operating position, an electrically operated ignition device for said burner, a circuit for said ignition device including said ignition contact, a starting circuit for one of said auxiliary elements connected to said ignition circuit by said transfer relay in the no flame position thereof, a starting relay having a contact in series in the energizing circuit to said mechanism, a circuit for energizing said starting relay, a cut-out relay having a contact in lseries in said circuit for energizing said mechanism and closed in the cle-energized position of said cut-out relay, a circuit for energizing said cut-out relay connected to said circuit for energizing said starting relay and including a switch closed by said transfer relay in the no flame position thereof, a second electrically driven timed switch mechanism having an energizing circuit and having a cut-out switch arranged to energize said circuits for energizing said cut-out relay and starting relay, an energizing circuit for said second mechanism being connected to be energized responsive to the closing of said ignition switch, an alarm device connected to said circuit for energizing said cut-out relay, a holding contact closed by said starting relay in its energized position to hold said starting relay in energized position, a second holding contact closed by said cutout relay in its energized position to hold said cut-out relay in energized position, and a manually controllable switch for de-energizing the circuits through said holding contacts.

14. Control apparatus for the burner vof a furnace comprising, electrically driven time delay switching mechanism having an energizing circuit and an ignition switch and cut-out switch, said switches being biased to open position, a transfer relay, an energizing circuit for said transfer relay including a switch responsive to the establishment of a flame in said burner,'an energizing circuit for said burner and having a running contact closed by said transfer relay in the flame operating position thereof and a starting contact connected to said circuit for energizing said mechanism by said transfer relay in the no flame position thereof, an electrically operated ignition device for said burner, a circuit for energizing said ignition device including said ignition switch, a starting relay having a contact arranged in series in the energizing circuit to said mechanism and closed in the energized-position of said starting relay, a circuit for energizing said starting relay including a switch closed by said transfer relay in the flame operating position thereof and said cut-out switch, a self operated holding contact on said starting relay, a cut-out relay having a cut-out contact in series in said circuit for energizing said mechanism, a circuit for energizing said cut-out relay including a switch closed by said transfer relay in the no flame position thereof and said cut-out switch on said mechanism, a self operated holding contact on said cut-out relay, a manually operable switch for de-energizing the circuits through said holding contacts, and a selectively operable element for directly connecting said cut-out switch on said mechanism to said circuit for energizing said starting relay to by-pass the switch on said transfer relay in the said circuit.

15. Control apparatus for the burner of a furnace comprising electrically driven time delay switching mechanism having an energizing circuit and an ignition switch biased to open position, an electrically operated ignition device for said burner, a circuit for said ignition device including said ignition switch and arranged to be open during the rst portion of the cycle of said mechanism, a starting relay having a contact in series to break the energizing circuit to said mechanism in the energized position of said starting relay, a circuit for energizing said starting relay including a second switch operated by said mechanism and arranged to close at a predetermined time after closing of said ignition switch, a self closed holding contact on said starting relay, a transfer relay, an energizing circuit for said transfer relay including a switch responsive to the establishment of a flame in burner, a cut-out relay having a contact in series to break said circuit for energizing said mechanism, a circuit for energizing said cut-out relay including a switch closed by said transfer relay in the no flame position thereof and said second switch on said mechanism, a self closed holding contract on said cutout relay, and a manually operable switch for de-energizing the circuits through said holding contacts.

16. Control apparatus for the burner of a furnace comprising electrically driven time delay switching mechanism having an energizing circuit and an ignition switch biased to open position, said mechanism being arranged to close said switch at a predetermined time after the start of the cycle of said mechanism, an electrically operated ignition device for said burner, a circuit for said ignition device including said ignition switch, a starting relay having a contact arranged in series to break the energizing circuit to said mechanism in the energized position of said starting relay, a circuit for energizing said starting relay including a second switch operated by said mechanism and arranged to close at a predetermined time after closing of said ignition switch, a self closed holding contact on said starting relay, and a manually operable switch for de-energizing the circuit through said holding contact.

17. Mechanism for obtaining a purging period and ignition period in a burner control system comprising, a pair of power supply switches biased to open position, electrically operated means for effecting a successive timed closing of said switches and operative to immediately release said switches as soon as said means is de-energized, an alarm circuit, an electrically operated ignition device in series with the first of said switches to be closed and arranged to be energized thereby, a pair of relays each having a switch in series with said electrically operated means and operative in the energized condition of its relay to de-energize said means, a

pair of energizing circuits one for each of said relays, a switch responsive to the establishment of a flame in said burner. and having contacts alternatively operative in the name operating and no flame positions of said fiame responsive switch, said contacts being connected in series in said energizing circuits to alternatively render one of said energizing circuits inoperative, said alarm circuit being connected to one of said energizing circuits to be energized therewith, and a common connection from the second of said pair of switches to said contacts on said flame responsive switch whereby closing of said second switch will alternatively energize either of said relays depending upon the position of said iiame responsive switch.

18. Mechanism for obtaining a purging period and ignition period in a burner control system comprising, a pair of power supply switches biased to open position, electrically operated means for effecting a successive timed closing of said switches and operative to immediately release said switches as soon as said means is de-energized, an electrically operated ignition device in series with the first of said switches to be closed and arranged to be energized thereby, a pair of relays each having a switch in series with said electrically operated means and operative in the energized condition of its relay to de-energize said means, a pair of energizing circuits one for each of said relays, a switch responsive to the establishment of a flame in said burner and having contacts alternatively operative in the ame operating and no ame positions of said flame responsive switch, said contacts being connected in series in said energizing circuits to alternatively render one of said energizing circuits inoperative, and a common connection from the second of said pair of switches to said contacts on said iiame responsive switch whereby closing of said second switch will alternatively energize either of said relays depending upon the position of said flame responsive switch.

HOMER C. NYCUM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,793,011 Ray Feb. 17, 1931 2,021,647 De Lancey Nov. 19, 1935 2,081,091 Kuempel May 18, 1937 2,136,256 Sweet Nov. 8, 1933 2,174,275 Raney Sept. 26, 1939 2,372,276 Isserstedt Mar. 27, 1945 2,388,666 Bower Nov. 13, 1945 2,425,589 Aubert Aug. 12, 1947

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