US3295583A

US3295583A - Restarter for thermostatically controlled oil and gas burners

Info

Publication number: US3295583A
Application number: US500661A
Authority: US
Inventors: Olds Ambrose Dean
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-10-22
Filing date: 1965-10-22
Publication date: 1967-01-03
Anticipated expiration: 1984-01-03

Description

Jan. 3, 1967 A D oLDs 3,295,583

RESTARTER FOR THRMSTATICALLY CONTROLLED OIL AND GAS BURNERS Jan. 3,

Filed D612. 22, 1965 @Los 3,295,583

RESTARTER FOR THERMOSTATICALLY CONTROLLED OIL AND GAS BURNERS 2 Sheets-Sheet 2 United States Patent O 3,295,583 RESTARTER FOR TI-IERMOSTATICALLY CONTROLLED OIL AND GAS BURNERS Ambrose Dean Olds, 35 Evergreen Drive, Centraia, Ill. 62801 Filed Oct. 22, 1965, Ser. No. 500,661 Claims. (Cl. 158-28) This invention relates in general to burner ignition. It deals more particularly with a system for igniting and re-igniting a gas or oil burner or the like.

When circumstances indicate that it is desirable to ignite a burner such `as a conventional warm ai-r furnace, or a thermostatic device automatically calls for the burners ignition, actuation of an ignition system is not always effective to achieve ignition. For example, on occasion the pilot flame has been blown out. Unburned fuel accumulates and poses a serious safety problem.

Electric ignition has partially solved this particular problem. Obviously, non-ignition of a burner upon actuation of an ignition system cannot occur due to pilot outage where a spark plug or coil is employed to ignite the fuel. Unfortunately, the great advantages of electric ignition are partially offset by inherent safety problems such as electric power failure, burned out ignition coils, fouled spark plugs, or even a plugged flue preventing the burning of fuel, although both fuel and ignition means are present. Obviously, protection against serious accumulation of unburned fuel is required even where electric ignition systems are employed.

The Underwriters Laboratory and the American Gas Association recognize the dangers -attendant to electric ignition. The Underwriters Laboratory, for example, will not approve a burner unless it turns olf the flow of fuel to the burner within ninety seconds after ignition is attempted, if flame is not sensed. An American Gas Association approved device must sense ame in from fifteen to 120 seconds after attempted ignition. Compliance with these requirements is generally achieved by electrically fired burners presently on the market, but,

unfortunately, their electric ignition `systems still leave A much to be desired.

Accordingly, it is an object of the present invention to provide a new and improved ignition and re-ignition system for a burner or the like.

It is another object to provide an ignition and res ignition system which precisely times a prescribed sta-rting period and, if the burned does not fire within the v period, locks out the flow of fuel and, accordingly, the

ing the burner.

It is yet another object to provide an ignition and reignition system in which any selected time period can be H established for reset of the system to attempt another ignition after lockout.

It is a further object to provide a system of the afore- 4 described character which can be .remotely reset by simple manipulation of .a conventional wall thermostat in a home, for example.

It is yet a further object to provide a system wherein i if ignition is successfully achieved, the system is automatically returned to a set or start condition for the next occasion that ignition is called for.

It is yet a further object to provide a new and improved ignition and re-ignition system wherein the precise timing of an ignition cycle is not effected by heat or voltage variation or the like.

It is another object to provide a system of the aforedescribed character which can be adjusted for constant lCe self-testing for operational readiness while the burner is operating properly.

It is still another object to provide a system wherein the timers inoperativeness when ignition is called for is effective to prevent fuel flow and spark propagation.

The foregoing .and other objects are realized in accord with the present invention by providing a system which electrically ignites a burner when heat is called for or, alternatively, locks out fuel flow to the `burner after a prescribed period of time during which ignition of the burner is not achieved. Ignition cycle time is precisely measured regardless of tem-perature variation ofthe System or variation of circuit voltage. To attempt to restart the burner if it goes out during operation or if it does not start at all upon demand, a simple circuit manipulation from a suitable remote location is all that is required. If ignition does occur, the system automatically resets itself for a restart when ignition is called for at some subsequent time.

An additional aspect of the invention resides in its ability to be adapted readily for the use of any selected rest period after lock out. In other word-s, if ignition is not achieved and lock out occurs, the reset period during which ignition cannot =be attempted ycan be Iadjusted to suit requirements.

The invention, together with its organization `and method of operation, taken with other objects and advantages thereof, is illustrated more or less diagrammatically in the accompanying drawings, in which:

FIGURE l is a schematic illustration of a basic form of ignition and re-ignition system embodying features of the present invention;

FIGURE 2 is an enlarged diagrammatic view of a cam operated switch incorporated in the system illustrated in FIGURE 1;

FIGURE 3 is a diagrammatic view of another cam operated switch in the system of FIGURE l;

FIGURE 4 is a schematic vie-w of ya first modified form of an ignition and re-ignition system embodying features of the present invention;

FIGURE 5 is an enlarged diagrammatic view of a cam operated switch incorporated in the first modified system illustrated in FIGURE 4;

FIGURE 6 is a diagrammatic view of another cam operated switch in the first modified system of FIG- URE 4; Y

FIGURE 7 is a diagrammatic view of still another cam operated switch in the first modified system of FIG- URE 4; and

FIGURE 8 is a schematic view of a second modified form of ignition and re-ignition system embodying features of the present invention.

Referring now to the drawings, and particularly to FIG- URE 1, a first or basic form of the system for igniting and re-igniting a conventional gas burner 10 according to the present invention is illustrated diagrammatically -at 11. The system 11 includes a conventional thermostat 12 which is manually adjustable to set a prescribed temperature below which the burner 10 is theoretically fired by the system 11, and above which the burner is extinguished.

The thermostat 12 is connected to an electrical circuit 13 embodying features of the present invention and if the temperature in a home, for example, falls below a prescribed figure, the thermostat is effective through the circuit to open a magnetically operated valve 21 of conventional construction and supply gas to the burner 10. At the same time, current is supplied to a high voltage transformer 22 in the circuit 13, causing a spark plug 23 to fire and, theoretically, igniting the gas in the burner 10. The burner 10 then operates until the thermostat 12 senses that the prescribed temperature has been reached,

whereupon the fuel valve 21 in the circuit 13 is automatically shut off.

It is, however, only when the burner is properly fired within a prescribed period of time that the system 11 continues to supply fuel to the burner through the valve 21. l In this light, when the burner 10 ignites, a conventional Wilcolator sensor 30 in the circuit 13 responds to heat produced by the burner flame and is effective upon its self-contained switch to cause the valve 21 to continue to supply fuel to the burner and current to the spark plug 23 for as long as the thermostat 12 is unsatisfied.

With the thermostat 12 as yet unsatisfied, and the burner 10 operating normally, a conventional synchronous motor 33 in the circuit 13 runs at a predetermined constant speed. It is the speed of the motor 33 which provides a precise measurement of the time period within which the system 11 must light the burner 10 or fuel flow to the burner is shut off. To this end, the motor 33 is effective to operate simple single pole, single throw microswitches MS1V and MS2 in the circuit 13 according to a predetermined schedule.

In the present illustration of the basic form of system 11, the schedule calls for a fifty-second ignition period, followed by a mandatory ten-second lockout If the burner 10 is fired within fifty seconds after the thermostat 12 demands heat, the sensor 30 senses flame and is effective to place a hold on the circuit 13 and supply fuel to the burner 10 for as long as the burner fiame is lit and the thermostat 12 unsatisfied. In other words, upon sensing fiame, the sensor 30 is effective to close a holding circuit 35 in the circuit 13 and hold it closed as long as flame is sensed. The motor 33 continues to manipulate the switches MS1 and MS2 during normal operation of the burner 10, maintaining the switches free of corrosion and the like without effecting the holding circuit 35.

Once the thermostat 12 is satisfied by its environmental temperature, the system 11 automatically resets itself for another ignition cycle when such is called for, all according to the present invention through the circuit 13. In other words, the motor 33 is automatically reset in its start or zero position for timing another starting cycle.

If the burner 10 does not fire and begins to operate properly within the fifty second ignition period, however, the sensor 30 is not effective to close the holding circuit 35 in the circuit 13. Consequently, after fifty seconds, the motor 33 opens the switch MS2 causing the circuit 13 to close the magnetically operated valve 21. Thev sytsem 11 is thus locked out and no more fuel can fiow to the burner 10. No explosion can occur as a result of a dangerous accumulation of gas, -for example.

To reset the system 11 for another attempt at igniting the burner 10, the thermostat 12 is merely adjusted downwardly to demand 4a temperature lower than that in the home at the time; for example, 60 F. The thermostat 12 is thus satisfied by the temperature of its environment and the circuit 13 is effective to start the motor 33 running again. According to the present illustration, the motor 33 runs for ten seconds and then opens the switch MS1 in the circuit 13 to stop the motor 33 once more.

The system 1] has now been reset in its zero or start position. At this point, the temperature setting of the thermostat 12 is raised to the higher desirable temperature, causing the circuit 13 to once again initiate operation of the motor 33, which has returned to its zero position for re-timing another ignition cycle, as pointed out. The fifty second ignition cycle is repeated.

Turning now to the details of the system 11, the circuit 13 includes a terminal W connected to a line (not shown) carrying 115 volt, sixty cycle current and a terminal B connected to ground. The terminal B is connected by a conductor 39 to the center terminal C of a conventional single pole, double throw switch 40 associated with the thermostat 12. Bracketing the center terminal C in the switch 40 is the terminal S (satisfied), which is connected to the center terminal C by the thermostat when its tem- (unsatisfied) requirement which is alternatively connected to the center terminal C by the thermostat when the temperature requirements of the thermostat are unsatisfied.

The terminals S of the switch 40 is connected by a conductor 41 to the terminal A of the switch MS1, while the terminal U is connected by -a conductor 42 to the terminal X of the sensor 30 and by a branch conductor 45 to the terminal A of the switch MS2. The terminal B of the switch MS2 is, in turn, connected by a conductor 50 to the terminal Y of the sensor 30.

A branch conductor 51 from the conductor 50 is connected to the terminal B of the switch MS1 While another branch conductor 52 from the conductor 50 is connected to one side of the motor 33. Still another branch conductor 56 extends from the conductor 50 to the one terminal of the high voltage transformer 22, while another branch conductor 57 connects the conductor 50 with the valve 21.

The opposite side of the motor 33 is connected by the conductor 58 to the hot line terminal W. 1n turn, branch c-onductors 59 and 60 connect the opposite sides of the transformer 22 and valve 21, respectively, to the conductor 58. The transformer 22 is connected in a well known manner to the spark plug 23.

Referring now to FIGURES 2 and 3, the shaft 62 of the motor 33 has two cams C1 and C2 mounted on it. The cam C1 has a uniformly recessed circular cylindrical periphery except for a single cam projection 65 wide.

enough only to hold the actuator 66 of the switch MS1 open, as illustrated in FIGURE 2, when the motor 33 and therefore, the cam C1 is in its start or zero degree position.

The cam C2 on the other hand has a uniformly recessed circular cylindrical surface along only 300 of its periphery and a projection 68 extends along 60 thereof. With i a motor 33 and accordingly, the cam C2 in its start or zero degree position, the actuator 69 of the switch MS2` has just fallen off of the cam projection 68 (the cams rotate in a clockwise direction, as seen in FIGURES 2 and 3), placing the switch MS2 in its normally closed relationship.

With the thermostat 12 satisfied, the motor 33 has automatically positioned the cams C1 and C2 in this start or zero position. The swtich MS1 is open, the switch MS2 l `is closed, the common terminal C of the single pole,

double throw switch 40 associated with the thermostat 12 is in contact with the terminal S thereof, and the terminals X and Y of the sensor 30 are open. No current ows through the circuit 13.

As the room cools -below the preset temperature of the thermostat 12, the thermostat 12 is effective upon the switch 40 to connect its center contact C with the contact U, disconnecting the contacts C rand S. Circuits are immediately completed through the closed switch MS2 to the motor 33, the transformer 22, and the valve 21. Gas fiows through the valve 21 to the burner 10 and a spark from the plug 23 is propagated to ignite the gas. The motor 33 turns the two cams C1 and C2 at la constant rate of one r.p.m. in the present illustration.

Once the motor 33 begins to rotate the cams C1 and C2, the cam C1 immediately permits the open switch MS1 to go to its normally closed position. The switch MS2 remains closed through 300 or fifty seconds of rotation of the motor 33 and cam C2 until the cam projection 68 engages the actuator 69 and opens the switch MS2. The completed circuits to the motor 33, the trans former 22, and the valve 21 through the switch MS2 areI opened and the system 11 has reached lockout, unless the burner 10 has been ignited during these fifty seconds.

If the burner 10 is ignited during this fifty second period, the sensor 30 senses heat from the burner flame and is effective to connect the terminals X and Y in its selfcontained switch and closethe holding circuit 35 tothe motor 33, transformer 22, and valve 21. This holding conductor, 50, through the closed terminals X and Y of the sensor 30 to the conductor 42, the conductor 42 through the U and C contacts of the switch 40 associated with the thermostat 12 to the conductor 39, and then to fthe ground terminal B.

This holding circuit' 35 supplies current to the motor 33, the transformer 22, and the Valve 21, as long as the thermostat 12 is unsatisfied, regardless of the open or closed condition of the switches MS1 or MS2. The motor 33 continues to rotate the cams C1 and C2, opening and closing the switches MSl and MS2 in each revolution of the motor. The switches MSI and MS2 are, accordingly, constantly operated to avoid corrosion or the like which might result in a malfunction during use after long quiescence. Y

When the thermostat becomes satisfied once more by a suitable temperature increase, it manipulates the switch 40 to reconnect the C and S contacts. Accordingly, the holding circuit 35 through sensor 30 is broken and a circuit completed to the motor through closed switchrMSl. Switch MSI remains closed until cam projection 65 contacts and opens it within the next 60 seconds andrthen the entire circuit 13 is open. The system 11 is thus automatically reset for the next ignition attempt when it is called for, all according to the present invention.

Since the Wilcolator sensor 30 is conventional in 'all respects, it is not shown in detail. Briefly, however, the

, sensor 30 consists of a small bulb conected by a capillary tube to a bellows. When the bulb is heated, mercury held therein causes the bellows to operate a self-contained switch and close the circuit through terminals X and Y. The Wilcolator sensor 30 is a standard commercial product.

Returning now to a description of the operation of the system 11 when lockout occurs 4after iifty seconds, it will be remembered that the switch MS2 is permitted to open at this time. Since the sensor 30 has not sensed flame at the burner 10, the contacts X and Y are not closed and current to the motor 33, the transformer 22, and the Valve 21 is shut olf. This situation also occurs, of course, if power fails in the system 11; lanother feature of the present invention.

Referring to the normal lockout situation, it now becomes necessary to reset the system 11 for another attempt to start the `burner 10. The thermostat 12 is manually reset below its environmental temperature so that it is satisfied. Accordingly, the thermostat 12 closes the contacts S and C of the switch 40, opening the contacts C and U. A circuit is immediately completed through the now closed switch MS1 to the motor 33. A circuit is Ialso completed to the transformer 22 and the Valve 21 in the basic system 11 (as will hereinafter be discussed in relation to the other forms of the present invention, the invention also contemplates initiating operation of only the motor 33 under these conditions). The motor 33 begins turning and turns the cams C1 and C2 through another ten degrees whereupon the switch MSI is opened by the cam projection 65 on the cam C1, opening the circuit to the motor 33 once more. At the same time, the switch MS2 has closed since the projection 68 on the cam C2 has moved in a clockwise direction out from under the actuator 69. The system 11 is now in its starting position ready to cycle another ignition attempt when the thermostat 12 is turned back to a normal 70 F., for example, and consequently is unsatisfied.

Turning now to FIGURE 4, a second form of system for igniting and reigniting a conventional gas burner is illustrated diagrammatically iat 111. The system 111 embodies the same basic concepts as the system 11 hereinbefore described. It does, however incorporate certain `modifications of the system 11 which might make it more attractive in practical application of the invention.

The system 111, for example, facilitates adjusting the ignition cycle time of the system and introducing a delay period after the ignition cycle during which the system remains at rest before it can be positioned for manual reset. The system 111 also provides for operating the motor 33 to time the manual reset period without coincidental operation of the high voltage transformer 22 and the valve 21.

As already recognized, the system 111 incorporated components identical to those described in relation to the system 11. As such, the system 111 includes a thermostat 12 a Valve 21 a transformer 22 a spark plug 23 a Wilcolator sensor 30 and a motor 33. The motor 33 carries cams C1 and C2 on its output shaft 62 and the vcams C1 and C2 are effective to operate ya single pole, single throw microswitch MSI and a single pole, double throw microswitch MS2. The cam C2 alternatively connects the front and back contacts B and A, respectively, ofthe switch MS2, with its center contact C by depressing or releasing its actuator 69 with the projection 68 on the cam.

The circuit in which the components are incorporated is slightly different than the circuit 13 hereinbefore discussed in relation to the system 11 and, accordingly, is identified by the reference numeral 113.v The circuit 113 includes, in addition to those components hereinbefore referred to,

another single pole, double throw microswitch MS3. Furthermore, a third cam C3 on the output shaft 62 of the motor 33 is effective tomanipulate the actuator 170 of lthe switch MS3 to alternatively connect the center contactC of the switch MSS with either theback contact A of the switch, or the front contact B thereof. The cam C3 lhas a recessed circular cylindrical periphery 171 in which the actuator 170 rides through the rst 180 of clockwise rotation of the cam C3 from the start or zer-o position, and a raised circular cylindrical projection 172 up onto which the actuator 170 is forced during the last 180ov of rotation of the cam C3. With the actuator 170 in the depressed periphery 171, the contacts C and B are connected. With the actuator 170 riding on Vthe -raised cam surface 172 during the last 180 of rotation of the cam, the contacts C and A are connected.

The circuit 113 further includes a conductor 139 which connects the B or ground terminal of the power source (not shown) with the C terminal of the switch 40 associated with the thermostat 12. A conductor 141 connects the S terminal of the switch to the A terminal of the switch MSI, while the B terminal of the switchMSl is connected to one side of the motor 33 by the conductor 142.

A conductor 145 connects the terminal U of the switch 40 to the front terminal B of the switch MS3, while a branch conduct-or 146 interconnects the conductor 145 and the front terminal B of the switch MS2. The outer terminal C of the switch MS2 is connected to the conductor 142 and, accordingly, to the one side of the motor 33 by a conductor 147. The center terminal C of the third microswitch MS3 is connected with the conductor 150 -to one side of the high voltage transformer 22, while a branch conductor 151 joinst-he conductor 150 to one side of the valve 21. The opposite side of the motor 33, the valve 21, and the transformer 22 are c-onnected to the hot line terminal W by a conductor and the branch conductors 161 .and 162, as illustrated.

The only remaining undescribed portion of the circuit 113 comprises its holding circuit 135. The holding circuit 135 includes the sensor terminals X and Y, and a conductor 165 extending from the terminal X to the conductor 145. A branched conductor 166, in turn, connects the terminal Y with the back terminals A 'of the microswitches MS2 and MS3.

Turning now to the operation of the lsystem 111, with the thermostat 12 satisfied the motor 33 has positioned the cams C1, C2, and C3 in their start or zero positions, as illustrated in FIGURES 5-7. Consequently, switch MESI is open, the switch MS2 and the switch MS3 are positioned so their center contacts C rand front contacts B are connected. The common terminal C of the switch 40` associated with the thermostat 12 is connected with the terminal S of the switch 40 and the terminals X Iand Y of the sensor 30 switch are unconnected. No current flows through the circuit 113.

As the room cools, the thermostat 12 is effective on the switch 40 to connect its center contact C with the contact U. A circuit is completed through the closed contacts C and B of the switch MS2 to the motor 33. At the same time, a circuit is completed through the switch MS3 via its closed center and front contacts C and B to the valve 21 and the transformer 22. Gas flows through the valve 21 to the burner 10 and a spark from the plug 23 is propsagated to light the fuel. The motor 33 turns the cams C1, C2 and C3 at a constant rate of 1 r.p.m.

The rotating cam C1 immediately permits the switch MS1 to close. The motor 33 continues rotating the cams C1-C3, gas continues to ow from the valve 21 to the fburner 10, and a spark continues to be propagated by the plug 23 until 30 seconds has passed in the present illustration and the projection 172 on the cam C3 forces the actuator 170 of the switch MS3 to connect the center contact C of the switch and the back contact A thereof, disconnecting the center contact from the front contact B.

v Circuits to the valve 21 and the transformer 22 are, consequently, broken and the system 11 is locked out.

If the burner fires during this thirty second ignition cycle period, however, the sensor 30 senses heat from the ame and is effective to close the terminals X and Y of its self-contained switch. Accordingly, the holding circuit 135 through the sensor 30 and the mcroswitch MS3, via its back terminal A and center terminal C, completes a circuit to the valve 21 and transformer 22. Fuel and spark continue to be supplied to the burner 10. The circuit through the switch 40 and front contacts C and B of switch MS2 remains closed except for a 10 second period every 60 seconds to continue to run motor 33. During that 10 second period the cam projection 68 switches MS2 to its back contact A connection and a holding circuit through conductor 166 keeps the motor 33 running during this time. Every thirty second as the single pole, double throw switch MS3 switches back and Yforth between its back contact A and its front contact B from the center contact C, the circuit to the valve 21 and the transformer 22 is transferred back and forth from the holding circuit 135 to the main circuit through the thermostat switch 40, but this has no effect upon the operation of the system 111.

When the burner 10 does not ignite during the first thirty seconds of operation of the system 111 seeking ignition of the burner, the valve 21 and transformer 22 are locked out in the manner described above. A circuit to the motor 33 is still closed, however, through the front contact B of the switch MS2, and the motor continues to rotate the cams C1-C3. After twenty more seconds or 120 additional degrees of rotation, the cam C2 switches the switch MS2 to its rear contact A, opening the circuit to the motor 33. This is known as positioning for manual reset. At this time, after fifty seconds, the system 111 is entirely locked out if the sensor 30 has not sensed ame.

The system 111 is reset for another attempt to start the burner 10 in the same manner as described in relation to the system 11. The thermostat 12 is manually reset at a temperature which is satisfied by environmental conditions. With the thermostat 12 satisfied, the switch 40 contacts C and S are closed, opening the contacts C and U, and completing a circuit through the closed switch MSl to the motor 33. The motor 33 turns the cams C1-C3 for sixty more degrees or ten seconds whereupon the cam C1 opens the switch MS1, deactivating the system 111 entirely. The system 111 is now in its starting position ready to cycle another ignition attempt when the thermostat 12 is turned back to a temperature where it is unsatisfied in its environment.

It will now be recognized 4that the system 111 has in-I troduced another adjustable variable in its control of ignition and re-ignition of a burner 10, for example. By varying the peripheral configuration of the cam C3, the

initial ignition cycle time can be varied anywhere from` ten to fifty seconds using a motor 33 which revolves at one r.p.m.

The system 111 retains the advantageous feature of automatic repositioning for re-start after the normal op-` eration of a burner 10 has raised the environmental tern-` When the thermostat 12 is` perature to that sought. satisfied, the thermostat opens the contacts C and U of the switch 40 and closes the contacts C and S. Circuits to the valve 21 and transformer 22 are broken while a back circuit through mcroswitch MSI to the motor 33 is closed. Consequently, the motor 33 continues to rotate the cam C1 until the projection 65 on the cam depresses the actuator 66 and opens the switch MS1.`

The system 211 incorporates components virtually identical to those described in relation to the system 11 and 111. As such, the system 211 includes a thermostat 12, a valve 21, a transformer 22, a spark plug 23, a sensor 30, and a motor 33. The motor 33 carries cams C1, C2, and C3 on its outputshaft 62, and the cams are effective to operate the single pole, single throw micro-` switches MS1, MS2 and MS3, respectively.

In contrast to the system111, the system 211 utilizes single pole, single throw microswitches MS2 and MS3. Furthermore, the sensor 30 is identical to a Wilcolator sensor -in all respects except that it includes la single throw, double pole, self-contained switch rather than a single pole, single throw switch. As a result, separate holding circuits 235a and 235b are provided, (a) to the motor 33, and (b) to the valve 21 and transformer 22, respectively.

In operation of the system 211, with the theromstat 12 satisfied, the motor 33 has positioned the cams C1,.

C2, and C3, in their start or zero position, as illustrated 1n FIGURES 5-7. Consequently, switch MSI is open, switch MS2 is closed, and switch MS3 is closed. The

common terminal C of the switch 40 associated with` the thermostat 12 is connected with the terminal S of the switch 40 and the terminals X, Y1 and Y2 are unconnected. No current fiows through the circuit 213.

As the room cools, the thermostat 12 is effective on the switch 40 to connect its center contact C with the contact U. A circuit is completed through the closed switch MS2 to the motor 33. At the same time, a circuit is completed through the closed switch MS3 through the valve 21 and the transformer 22. Gas flows through the valve 21 to the burner 10 and a spark from the plug 23 is propagated to light the fuel. the cams C1, C2, and C3 at a constant rate of 1 r.p.m.

The rotating cam C1 immediately permits the switch MS1 to close. The motor 33 continues to rotate the cams C1-C3, gas continues to flow from the valve 211 10 doesnt fire during the thirty seconds, the projection i The motor 33 turns 172 on the cam C3 forces the actuator 170 of the switch MS3 to open the contacts AB of the switch MS3, disconnecting circuits to the valve 21 and the transformer 22.

If the burner fires during this thirty second ignition cycle, however, the sensor 30 senses heat from the ame and is effective to close the terminals X, Y1 and Y2 of its self-contained switch.- Accordingly, holding circuits 235:1 through the switch MS2 to the motor 33, and 235b through the switch MS3 to the valve 21 and transformer 22, are closed. Fuel and spark continue to be supplied to the burner 10.

When the burner 10 does not ignite during the first thirty seconds of operation of the system 211 seeking ignition of the burner, Ithe valve 21 and transformer 22 are shut off in the manner described above. The circuit to the motor 33 is still closed, however, through the switch MS2 and the motor continues to rotate the cams C1-C3. After twenty more seconds or 120 additional degrees of rotation, the cam C2 opens the switch MS2 opening the circuit to the motor 33. This -twenty second period is referred to as positioning for manual reset, as has previously been pointed out. yAt this time, after fifty seconds, the system 211 is entirely locked out if the sensor has not sensed the flame.

The system 211 is reset for another attempt to start the burner 10 in the same manner described in relation to the system 11 and 111. The thermostat 12 is manually reset at a temperature which is satisfied by environmental conditions. With the thermostat 12 satisfied, the switch 40 contacts C and S are closed, opening contacts C and U and completing a circuit through the closed switch MSl to the motor 33. The motor 33 turns the cam C1-C3 for sixty more degrees or ten seconds, whereupon the cam C1 opens the switch MSI, deactivating the system 211 entirely. The system 211 is now in starting position ready to cycle another ignition attempt.

Like the system 111, the system 211 retains the advantageous feature of automatic repositioning for restart after the normal operation of a burner 10 has raised the environmental temperature to that sought. In other fwords if, as usually happens, the cams C1-C3 are not in `their start or zero position when the thermostat switch 40 switches from unsatisfied to satisfied during normal operation of the system 211, a circuit to the motor 33 remains closed through the microswitch MS1 and continues to rotate the cams C1-C3 until they have reached their zero or start position, whereupon the entire system 211 is inactivated until the thermostat 12 again calls for increased temperature.

Both the systems 111 and 211A may be modified according to the present invention to provide yet an additional safety feature. This feature assures that if, for some reason, the motor 33 should fail to start upon its circuit being completed through operation of the switch 40 as energizedby the thermostat 12 upon a demand for heat, fuel will not be supplied to the burner, nor will a spark be propagated. This safety protection is achieved by a slight angular adjustment or construction modification of the projection 172 on the cam C3.

For example, referring to FIGURE 7, it will be seen that rotation of the cam C3 counterclockwise on the shaft 62 for several degrees (to dotted line position) will cause the projection 172 to force the switch actuater 170 upwardly and open the switch MS3 (for system 211 or switch it to its back contact A for the system 111) when the system is in its zero or start position. Accordingly, until the shaft 62 is turned slightly clockwise from the start or zero position by operation of the motor 33, circuits to the valve 21 and transformer 22 are not closed. The length of the projection 172 can easily be adjusted, of course, to set any prescribed ignition period.

Referring to the setting of prescribed ignition periods and the like, it should also be recognized that the ignition period and rest period, for example, can also be changed by merely varying the speed of the motor. The systems 10 11, 111, and 211 have been described in the context of a motor 33 which -turns the shaft 62 at one r.p.m., but any desired motor speed might be utilized to obtain an ignition period, for example, of prescribed length.

While several embodiments described herein are at present considered to be preferred, it is understoodthat various modifications and improvements may be made therein, and it is intended `to cover in the appended claims all such modifications and improvements as fall within their scope. v l

What is desired to be claimed and secured by Letters Patent of the United States is:

1. A system for controlling the ignition and re-ignition of a burner comprising: circuit means including a source of current, electrical fuel control means, electrical fuel firing means, sensor means for sensing fiame at the burner, timer means, operator switch means, and timer switch means, movement of said operator switch means into a first alternative condition when said system is in its normal start or zero position completing circuits to said timer means and to said fuel control means and said fuel firing means to attempt ignition of said burner, said timer means timing a predetermined ignition period, normal firing of the burner during said ignition period being sensed by said sensor means which then closes holding circuits to said timer means, and said fuel control means, said timer ,means continuing lto operate as long as said burner is fired while cyclically operating said timer switch means, movement'of said operator-switch means into a second alternative condition while said burner is normally fired being effective to open the circuit to said fuel control means and complete another circuit to said timer means Ito operate said timer means until said normal start or zero position is reached once more, whereupon said timer switch means is effective to open the closed circuit to said timer means and prepare said system for anotherignition attempt when said operator switch means again moves into said first alternative condition, said timer means manipulating said timer switch means if ignition is not successfully obtained during said predetermined ignition period to break the circuit to and lock out said electrical fuel control means, said A timer means also manipulating said timer switch to break its own closed circuit and lock itself out after said unsuccessful ignition period, manipulation of said operator switch means into said second alternative condition after said lock out being effective to complete a circuit to Vsaid timer means to cause said timer means to time a prescribed reset period and then manipulate said timer switch means to open the circuit to said timer means once more at said normal start or zero position.

2. The system of claim 1 further characterized in that if ignition is not successfully obtained during said predetermined ignition period and said electrical fuel control means is locked out, said timer means continues to operate for a rest period of predetermined length during which ignition is not attempted before manipulating said timer switch means to break its own closed circuit and lock itself out, lock out of said fuel control means and said timer means occurring at a time before start position is reached equal to the length of said reset period, if ignition is not successful.

3. The system of claim 1 further characterized in that movement of said operator switch means into said first alternative condition when said system is in its normal start or zero position first completes a circuit to said timer means and subsequently completes circuits to said fuel control means and said fuel firing means only if said timer means becomes operative so that ignition will not be attempted if said timer means is inoperative.

4. The system of claim 1 further characterized in that said operator switch means comprises a temperature responsive thermostat, said first alternative condition is in effect when said thermostat is unsatisfied by environmental temperature and said second alternative condition is in effect when said thermostat is satisfied by its environmental temperature, whereby said system is manipulated for attempted ignition of said burner after an unsuccessful ignition attempt by manually setting said thermostat in an unsatisfied condition.

5. The system of claim 1 further characterized in that said timer switch means comprises a plurality of switches interposed in said circuit means between said operator switch means and said timer means, said fuel tiring means, and said fuel control means, said timer means comprising a constant speed electric motor driving a plurality of cams, said cams being effective to manipulate said switches and accordingly control operation of the timer means, the fuel control means, and the fuel fire means, according to a predetermined schedule.

6. The system of claim 5 further characterized in that there are three of said switches; switch one, switch two, and switch three, switches one and two cooperate to control operation of said motor, and switch three controls the operation of said fuel control means and said fuel firing means.

7. The system of claim 6 further characterized in that said switches are single pole, single throw switches, and said sensor means includes and is effective to operate a single pole, double throw switch in said circuit means.

8. The system of claim 6 further characterized in that switches two `and three are single-pole, double-throw switches, and said sensor means includes and is effective to operate a single pole, single throw switch in said circuit means.

9. A system for controlling the ignition and re-gnition of a burner comprising: circuit means including a source of current, electrical fuel control means, electrical fuel firing means, sensor means for sensing flame at the burner, timer means, operator switch means, and timer switch means, movement of said operator switch means to a closed position when said system is in its normal start or zero position completing circuits to said timer means and to said fuel control means and said fuel firing means to attempt ignition of said burner, said timer means timing a predetermined ignition period, normal ring of the burner during said ignition period being sensed by said sensor means which then closes holding circuits to said timer means, and said fuel control means, said timer means continuing to operate as long as said burner is tired while cyclically operating said timer switch means, movement of said operator switch means to an open position while said burner is normally tired being effective to provide at least a circuit to said timer means to operate said timer means until said normal start or zero position is reached once more, whereupon said timer switch means is effective to open the closed circuit to said timer means and prepared said system for another ignition attempt when said operator switch means again moves into said first -alternative condition, said timer means manipulating said timer switch means if ignition is not successfully obtained dun'ng said predetermined ignition period to break the circuit to and lock out said electrical I fuel control means, said timer means also manipulating said timer switch to breakits own closed circuit and lock itself out after said unsuccessful ignition period, manipulation of said operator switch means after said lock out being effective to complete a circuit to said timer means i to cause said timer means to time a prescribed reset period and then manipulate said timer switch means to open the circuit to said timer means once more at said normal start or zero position.

10. A system for controllingV the ignition and reignition of a burner, comprising: circuit means including a source of current, electrical fuel control means, electrical fuel ring means, sensor means for sensing -ame at the burner, timer means, operator switch means, and timer i switch means, movement of an operator switch means into i a rst alternative condition when said system is in its normal start or zero position completing circuits to said timer means and to said fuel control means; and said fuelring means to attempt ignition of said burner, said timer means timing a predetermined ignition period, nori mal tiring of the burner during said ignition period being sensed by said sensor means which then closes holding circuits to said timer means and said fuel control means,

said timer means continuing to operate as long as said burner is fired while cyclically operating said timer switch means, movement of an operator switch means into a second alternative condition while said burner is normally red completing another circuit to said timer means to operate said timer means until said normal start or zero i position is reached once more, whereupon said timer switch means is effective to open the closed Circuit to said period to break the circuit to and lock out said electrical `fuel control means, said timer means also manipulating said timer switch to break its own closed circuit and lock itself out after said unsuccessful ignition period, manipulation of manual means after said lock out being effec-` tive to complete a circuit to said timer means to cause; said timer means to time a prescribed reset period and then manipulate said timer switch means to open the circuit to said timer means once more at said normal start or zero position.

References Cited by the Examiner UNITED STATES PATENTS 1,877,037 9/1932 Parker 158-28 i 2,325,440 7/ 1943 'Townsendv 158-28 3,143,162 8/1964 Graves et al 158-28 i JAMES W. WESTHAVER, Primary Examiner.

Claims

1. A SYSTEM FOR CONTROLLING THE IGNITION AND RE-IGNITION OF A BURNER COMPRISING: CIRCUIT MEANS INCLUDING A SOURCE OF CURRENT, ELECTRICAL FUEL CONTROL MEANS, ELECTRICAL FUEL FIRING MEANS, SENSOR MEANS FOR SENSING FLAME AT THE BURNER, TIMER MEANS, OPERATOR SWITCH MEANS, AND TIMER SWITCH MEANS, MOVEMENT OF SAID OPERATOR SWITCH MEANS INTO A FIRST ALTERNATIVE CONDITION WHEN SAID SYSTEM IS IN ITS NORNAL START OR ZERO POSITION COMPLETING CIRCUITS TO SAID TIMER MEANS AND TO SAID FUEL CONTROL MEANS AND SAID FUEL FIRING MEANS TO ATTEMPT IGNITION OF SAID BURNER, SAID TIMER MEANS TIMING A PREDETERMINED IGNITION PERIOD, NORMAL FIRING OF THE BURNER DURING SAID IGNITION PERIOD BEING SENSED BY SAID SENSOR MEANS WHICH THEN CLOSES HOLDING CIRCUITS TO SAID TIMER MEANS, AND SAID FUEL CONTROL MEANS, SAID TIMER MEANS CONTINUING TO OPERATE AS LONG AS SAID BURNER IS FIRED WHILE CYCLICALLY OPERATING SAID TIMER SWITCH MEANS, MOVEMENT OF SAID OPERATE SWITCH MEANS INTO A SECOND ALTERNATIVE CONDITION WHILE SAID BURNER IS NORMALLY FIRED BEING EFFECTIVE TO OPEN THE CIRCUIT TO SAID FUEL CONTROL MEANS AND COMPLETE ANOTHER CIRCUIT TO SAID TIMER MEANS TO OPERATE SAID TIMER MEANS UNTIL SAID NORMAL START OR ZERO POSITION IS REACHED ONCE MORE, WHEREUPON SAID TIMER SWITCH MEANS IS EFFECTIVE TO OPEN THE CLOSED CIRCUIT TO SAID TIMER MEANS AND PREPARE SAID SYSTEM FOR ANOTHER IGNITION ATTEMPT WHEN SAID OPERATOR SWITCH MEANS AGAIN MOVES INTO SAID FIRST ALTERNATIVE CONDITION, SAID TIMER MEANS MANIPULATING SAID TIMER SWITCH MEANS IF IGNITION IS NOT SUCCESSFULLY OBTAINED DURING SAID PREDETERMINED IGNITION PERIOD TO BREAD THE CIRCUIT TO AND LOCK OUT SAID ELECTRICAL FUEL CONTROL MEANS, SAID TIMER MEANS ALSO MANIPULATING SAID TIMER SWITCH TO BREAK ITS OWN CLOSED CIRCUIT AND LOCK ITSELF OUT AFTER SAID UNSUCCESSFUL IGNITION PERIOD, MANIPULATION OF SAID OPERATOR SWITCH MEANS INTO SAID SECOND ALTERNATIVE CONDITION AFTER SAID LOCK OUT BEING EFFECTIVE TO COMPLETE A CIRCUIT TO SAID TIMER MEANS TO CAUSE SAID TIMER MEANS TO TIME A PRESCRIBED RESET PERIOD AND THEN MANIPULATE SAID TIMER SWITCH MEANS TO OPEN THE CIRCUIT TO SAID TIMER MEANS ONCE MORE AT SAID NORMAL START OR ZERO POSITION.