US2183967A - Control apparatus - Google Patents

Description

19, 1939. J, Rvm ET AL 2,183,967

CONTROL APPARATUS Filed Nov. 10. 1957 s Sheets-Sheet 2 L m E I E 5 A72 INVEIIVTOR- Dec. 19, 1939. J. T. MARVIN El AL 2,183,967

CONTROL APPARATUS Filed Nov. 10, 1937 3 Sheets-Sheet 3 IN VENTOR.

w H m @W ATTORNEY. J

Patented Dec. 19, 1939 2,183,967 comaor. APPARATUS John '1. Marvin, Dayton, and Eldon D. l'taney,

Columbus, Ohio, assignors to Banco Incorporated, Columbus, Ohio, a corporation of Ohio Application November 10, 1937, Serial No.'173,882 6 Claims. (Cl. 158-28) The present invention relates to control systems andmore particularly to electrical control systems for controlling fuel burning apparatus.

One of the objects of the present invention is to provide a control system, such as a control system for a fuel burner which utilizes an ignition device, and in which the ignition device is rendered inoperative after a timed period of starting of the burner and reset upon denergization of the system, so as to insure ignition upon the restarting of the system. i

Another object of the invention is to provide control system with an electrically heated timing device which is heated continuously during the operating period of the fuel burning device and which controls the period of operation of ignition and, also, to provide for modifying he heating effect of the device after a predete ed period of operation thereof.

Other and further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a diagrammatic view of a control sys tem in position; immediately after energization of the system; I Fig. 2 is a diagrammatic view of a control apparatus and switches, in the operating position, during an operating period of the fuel burning device; 1

Fig. 3 is a view similar to Fig. 2 with the apparatus and theswitches in position immediately after deenergization of the system;

Fig. 4 is a view similar to Fig. 2 with; the apparatus in position prior to energlzation of the system, and,

Fig. 5 is a view similar to Fig. 2, with the apparatus in the deenergized position due to flame failure, a similar action occurring upon failure to initially establish combustion.

Referring to Fig. 1 the present invention is shown in connection with an oil burning device. The system is operatively responsive to the action of a room thermostat 28, which closes the secondary circuit of the system, when there is a demand for heat, and which opens the same when the demand has been satisfied. A transformer relay 22 is utilized to supply low voltage current to the secondary or-starting circuit of the system and also to actuatevarious associated chored at 51, and-a contact 54 located on its free end. A spring member 28 having one end fixedly 54 will engage contact 38 when the member 56 is moved to the left. The spring member 28 is biased normally against the stop IS. A fixed contact 32 is suitably mounted for contact with the contact 38. The bimetal member 56, the member 28 and contact 32 are connected in the secondary circuit by the wires 58, 26 and 34 respectively.

When the bimetallic member 56 6001s its free end moves to the left, as viewed in Fig.- l, and brings the contact 54 against the contact 38. The secondary circuit is not energized at this point, however, due to the fact that the contacts 38 and 54 are in series with the switch 52, which switch is not closed until the secondary circuit is enermember 28, contacts 38 and 32, wire 34, heatingv coil 36, contacts 38 and 48 of time delay switch 42, resilient contact member 44, and wire 46.

Completion of thesecondary circuit causes the transformer relay 22 to draw its armature 48 upwardly to close the associated switches 58 and 52 (as shown in Fig. l) Closure of switch 52 completes a holding circuit around the contact 32 of the thermostat 28. This circuit may be traced as follow'sz. secondary 24, wire 26, member 28, contacts 38 and 54 and bimetal 56 of thermostat 28, wire 58, switch 52, wire 34, heating coil 36, time delay switch 42, contact member 44 and wire 46.

the ndary circuit through'the contacts 38 and 54 until the member 28 is arrested by the stop [9. When the member 28 rests against the stop Is, the contact 54 will be moved away from the contact 38 by further movement of the bi-' metallic member and the secondary circuit will then be opened and deenergized.

The high voltage primary circuit, includes the primary coil 68 of transformer relay 22 and may be traced as follows: wires I8 and 80, primary coil 68, wires 66 and 64, safety switch 62 and wire 60. Wires 60 and I8 connect directly to the high voltage line. Thus the primary coil 68 is continuously, energized when safety switch 62 is closed.

Closure of switch 50, by the armature 48 energizes the motor and ignition circuits. The motor circuit may be traced as follows: wire I8, motor I6, wire I2, switch 50, wire I0, wire 64, safety switch 62 and wire 60. The primary I4 of the ignition transformer I5 is preferably placed in parallel with the motor through the ignition switch 84; such circuit includes wires I8, 80 and 82, ignition switch 84, wire 86, ignition primary I4, wire I2, switch 50, wires I and 64, safety switch 62 and wire 60. Thus it is apparent that closure of switch 50 energizes the motor I6 and ignition primary I4 substantially simultaneously.

The motor I6 is utilized to propel pump means for supplying oil and air to the fuel burning device or to operate a fuel valve. A suitable ignition device 13 is also provided and is connected. with the secondary II of the ignition transformer to ignite the fuel.

The heating coil 36 is disposed in intimate heat transfer relation with a U-shaped bimetallic element or thermostat 90. Upon energization of the secondary circuit of the system, the heating coil 36 is rendered effective and heats the bimetal 90 to cause the same to deflect upwardly. The bimetal 90 carries a push rod 92 on its upper blade, which rod 92 has a lost mo-' tion connection 94 at the upper end thereof which engages a flipper 96 of a snap acting toggle mechanism 98. The free end of flipper 96 carries a bridging member I00 disposed to bridge contacts I02 and I04 when the flipper is in its upper, or snapped position. Thus, as the bimetal 80 moves the push rod 92 upwardly, due

to the continuous heating by the coil 36, the

flipper 96 snaps upwardly to cause the bridging member I00 to engage contacts I02 and I04 of switch I06. Closure of the switch I06 shunts out a part of the heating coil 36 thereby rendering the shunted part substantially ineffective. In this position current from thetime delay switch 42 traverses part of the heating coil 36, wire I08, switch I06, wire IIO, back to wire 34. When the heating coil 36 is partly shunted it still has suflicient heating effect to maintain the bimetal 90 in its upper position wherein the flipper 96 has been snapped to close switch I06.

anism 98, which period assures that the ignition device has been operative for a sufllcient period to ignite the' fuel.

When combustion has been established,' a combustion responsive control II4 causes an as- 'sociated lever II6 to be moved to the riBht so that the end thereof is in a position to engage the outer end of flipper 2 when the same is snapped upwardly, so that the flipper remains in the upper position. In this manner the upward movement of the flipper H2 is limited by 'theoontroller II4 (as shown in 2).

The combustion control H4 is associated with lever II6 by a conventional slip clutch which provides for substantially immediate movement of lever II6 upon a change in temperature of the controller 4.

In the event of failure to establish combustion, the controller H4 is not moved and the lever II6 remains in the position shown .in Fig. 1. In this case, the flipper II2 snaps upwardly until it engages the end of a downwardly ex tending, pivotally mounted latch lever II8, the other end I20, of the lever II8 being utilized to latch a pivotally mounted spring biased lever I22, to maintain the associated safety switch 62 in circuit closing position. Engagement of the downwardly extending end-of latch lever II8 by the flipper II2 causes the lever II8 to release the latch I20 from lever I22 which allows a spring I24 to separate the contacts of the safety switch 62 to deenergize the system (as shown in Fig. When this action occurs the system remains deenergized until the safety switch 62 is I reset manually.

wardly to cause the safety switch 62 to be opened.

The time period between failure of combustion and operation of the safety switch 62 depends only on the time required for the control II4 to withdraw lever II6.

When the system is deenergized, either nor-, maily, that is, by'the opening of thermostat 20, or due to a power failure, the armature 48 drops downwardly to simultaneously bear upon two vertically extending push rods I26 and I28. This action, due to the weight of the armature 48 on rod I26, causes the resilient contact member 44 to drop downwardly until the same engages the fixed stop I30, in which position the time delay switch 42 is open circuited. Obviously the system cannot be reenergized until the bimetal 90 has cooled sufliciently to close the time delay switch 42. The action of the armature on push rod I28 closes the ignition switch 84. The rod I28 is slidably journalled in suitable bearings, and when acted upon by the armature causes the flipper II2 to be depressed sufliciently to close the ignition switch 84 (as shown in Fig. 3). It is apparent that during this action the flipper 96 is still in the upper position. Upon deenergization of heating coil 36 the bimetal 90 cools and draws the rod 92 downwardly to cause the connection 94 to engage the flipper 96 and draw it downwardly until it passes the dead center position of'the toggle mechanism 90, at which instant the flipper 96 snaps downwardly through the lost motion connection 94 (as shown in Fi 4) From the foregoing it will be observed that whenever the transformer relay 22 is deenergized, the ignition switch 84 is immediately closed by the action of the armature through the rod I28 and therefore the ignition device is in readiness to operate whenever the secondary or starting circuit is reenergized.

In the embodiment shown in Fig. 1, the bimetal is provided with a compensator |3I which compensator comprises a bimetal I32, of s milar shape to the bimetal 90, fixedly mounted at I34. Bimetal I32 is resilicntlyconnected to the bimetal 86 by a double headed rivet; I36, which passes looselythrough both bimetals, and a spring I38 disposed around the rivet I36 and compressed between the bimetals. The bimetal I32 is so formed, that upon application of heat thereto, it deflects in the opposite direction to the bimetal 90. Thus when the room temperature rises, bi-

switch 62 will always be operative within a set time interval.

The present invention can be very satisfactorily operated with a conventional two wire thermostat in place of thermostat 20, in which case the switch 52, and the wiring necessitated thereby, ,can be eliminated. It is likewise possible to utilize the disclosed principle of closing the ignition switch upon deenergization of the system, with other types of control systems without departing from the scope of the invention.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adapted,all coming within the scope of the claims which follow:

We claim:

1. A control system for a fuel burning device comprising electrically operated means for start-" ing said device; a normally closed time delay switch in circuit with the said means; electrically heated thermal means adapted to control the operation of said swtich, said thermal means being energized simultaneously with the starting of said fuel burning device; means operated by the electrically heated thermal means, after a predetermined period of heating thereof, for

modifying the heating effect of said thermal means; and means operated by the electrically operated means when the same is deenergized, for opening the time delay switch for causing a delay between successive energizations of the electrically operated means, the duration of said delay being governed by the cooling of said thermal means to cause said switch to close.

2. A control system for a fuel burning device comprising, electrically operated means for startingthe device; an electrically operated safety mechanism in circuit with said means capable of rendering the circuit inoperative, said mechanism including an electric heater, said heater being energized by said means upon the starting of the fuel burning device and maintained energized during the operation of said device; means rendered effective by the safety mechanism for reducing the heating effect of the heater; and means responsive to the establishment of combustion for preventing-said safety mechanism from rendering said electrically operated means inoperative.

3. In a control system for a fuel burning appar atus, an electrically operated device for controlling starting of the apparatus; a normally .closed safety switch for controllingsaid apparatus; an ignition means including a switch; an electrically heated timing means for actuating the safety and ignition switches to their open positions, said timing means being continually energized during operation of the apparatus; means responsive to combustion for preventing movement of the safety switch to its open position; and means independent of said timing means actuated by said device for biasing and maintaining the ignition switch in its closed position when the apparatus is deenergized. I

4. In a control system for a fuel burning apparatus, an electrically operated device for controlling operation of the apparatus; a normally closed safety switch in circuit with the said device; means for igniting the fuel, said means including an ignition switch; thermal responsive means adapted to move in one direction when heated for causing-successive opening of the ignition switch and the safety switch respectively; electric heating means for said thermal responsive means; a circuit for the heating means, said circuit being connected with the'electrically operated device and energized continually during operation of the apparatus; .means for arresting movement of said thermal responsive means in response to the presence of combustion following opening 'of the ignition switch and prior to opening of the safety switch by the thermal means; and means independent of said thermal respon sive means actuated by said electrically operated device for biasing the ignition switch in its closed position on stopping of the burner apparatus.

5. A control system for a fuel burning device comprising in combination, an igniter; .a circuit for the igniter including two .switches; electrically operated means having a running position and a stopping position, said means when moved to the running position closing one of the igniter circuit switches and adapted to render the fuel burning device operative and, when moved to stopping position, opening said one switch and closing and maintaining the other of said igniter switches closed; means for actuating the electrically operated means; and an electrically operated timing device operable after the electrically operated means is moved to the running position, for causing the electrically operated means to be moved to the stopping position and foropening said other igniter switch; and means responsive tothe establishment of combustion for preventing said timing device from causing the electrically operated means to be moved to the stopping position. v

6. A control system for a fuel burning device comprising in combination, an igniter; a circuit for the igniter including two switches; electrically operated means having a running position and a stopping position, said means when moved to the running position closing one of the igniter circuit switches and adapted to render the fuel burning device operative and, when moved to stopping position, opening said one switch and closing and maintaining, the other of'said ignition switches closed; means' for actuating the electrically operated means; and an electrically'operated timing device, continuously energized while the electrically operated means is in the running position, said timing device being operable, after the electrically operated means is moved to the running position, for causing the electrically operated means to be moved to the stopping position and for opening said other igniter switch; and means responsive to the establishment of combustion for preventing said timing device from causing the electrically operated means to be moved to the stopping position;

. JOHN T. MARVIN.

ELDON D. RANEY.

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