US 3115180 A
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Description (OCR text may contain errors)
J. A. DEUBEL Dec. 24, 1963 REMOTE RESET SAFETY CONTROL FOR GASEOUS FUEL BURNERS Filed Sept. 21. 1959 INVENTOR wsrf/V EUEEL rroQA/Eys.
United States Patent vOficfr 1....,... D... 2., 1963 3,115,180 REMOTE RESET SAFETY CONTROL FOR GASEOUS FUEL BURNERS Justin A. Deubel, Milwaukee, Wis., assign'or to General Controls Co., Glendale, Calif., a corporation of California Filed Sept. 21, 1959, Ser. No. 841,092 4 Claims. (Cl. 158-124) This invention relates to the control of gaseous fuel burners equipped with pilot burners, and particularly to suchcontrols that ensure shutting down of the system in the event of failure of the pilot flame or in the event that the ignition of the pilot flame is not effected when there is a demand for heat.
In the system to be herein described, the demand for heat normally results first in the ignition of the pilot burner, the energization of a fan if used, and then the opening of the main burner valve. After the pilot flame is established, the ignition circuit is deenergized.
The system is rendered inactive when the demand for heat no longer exists; the pilot burner Valve is closed and, accordingly, a cycle of control operations is started anew as soon as the demand for heat arises.
It is an object of this invention to fulll the following requirements. Should the pilot flame fail to be stabily ignited at the initiation of operation, after a predetermined time the system is automatically rendered inactive. Manual reset operation may be effected by momentarily opening the thermostat.
Accidental extinguishing of the pilot flame while the demand for heat continues causes reenergization of the igniter circuit. If there is continued failure to ignite the pilot burner, then a manual reset operation is again required.
It is another object of this invention to provide a simple and effective control system incorporating these functions.
It is another object of this invention to provide a, satisfactory control system in which there is a complete shut-down of the system at the conclusion of the period of heat demand.
It is still another object of this invention to provide a safety system of simple character that fails safe and permits manual reset by use of the space thermostat or a remote switch.
This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose, there is shown a form in the drawings accompanying and forming part of the present specification. This form will now be described `in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.
Referring to the drawing:
The single FIGURE is a diagrammatic representation of an electric control system incorporating the invention.
In the drawing there are illustrated a main burner 1 and its pilot burner 2, adapted to be located in a heating furnace 1a. The main burner 1 is controlled by a main burner valve 3 which may be electromagnetically operated. The pilot burner 2 is likewise controlled by a pilot burner valve 4, also preferably electromagnetically operated.
A thermostatic switch 5 includes a thermostat and a circuit controller. When the thermostat, which may be located in a room to be heated, demands more heat, it closes the switch contacts and initiates the operation of the system, whereby the pilot burner valve 4 is opened and the pilot burner ignited by a glow coil 6. After the pilot flame 7 is established, then the main burner valve 3 will open so that the main burner 1 will be ignited.
The main llame 8 and the pilot burner flame 7 are shown in phantom lines to indicate that the system is in a quiescent position, both the main burner 1 and pilot burner 2 being shut down.
The electrical energy for operating the control system is derived from the commercial mains 9 and 10.
When the thermostat 5 requires more heat, control circuits are energized in a manner now to be described. A transformer 11 has a primary winding 12 connected across the mains 9 and 10. Its secondary winding 13 is connected in series with the thermostat switch 5.
When the thermostat switch closes, corresponding to a requirement for more heat, a circuit through the switch is established through secondary winding 13, a reset button 14, relay coil B, back contact A2 of a relay A, and thence to the thermostat switch 5. The contacts A2 open when the relay A is energized in a manner hereinafter to be described. Therefore, the back contacts A2 are normally closed, and the circuit through the relay B is thus established.
As soon as relay B is energized by closing of switch 5, two front contacts B1 and B2 of that relay are closed. As an immediate result of the closing of contacts B2, a circuit is established from main 9 through blower fan 1S to main 10. This blower fan is thus energized for moving the air from the furnace 1a to the space to be heated. As soon as the fan comes up to speed, a centrifugal switch 19 is closed.
The closing of front contacts B1 energizes the pilot burner valve 4, the circuit of which may be traced as follows: the main 9, contacts B1, conductor 16, valve 4, conductors 17 and 18, centrifugal switch 19, back to main 10. Accordingly, there is assurance that there is a movement of air from furnace 1a before the main burner 1 may be ignited.
At the same time, a circuit is established through the igniter coil 6 by way of a circuit controller 20 that is normally closed while the pilot burner is inactive and which opens when the pilot burner flame 7 is established. Such pilot switches are now well-known.
The circuit controller or switch 20 controls the energization of a transformer 21. The primary winding 22 of the transformer 21 is in series with the switch 20. By way of conductor 18 and centrifugal switch 19, the circuit for the igniter transformer primary winding 22 is completed.
The secondary winding 23 of the transformer 21 supplies current at the proper potential to operate the ignition or glow coil 6.
Let us assume that the pilot burner llame 7 has been established. As soon as this occurs, the circuit controller 20 opens, deenergizing the igniter 6; and the circuit controller 24 is closed, corresponding to the existence of the flame 7. Closing of this circuit establishes a circuit from main 9 to main 10 through the main burner valve 3. This circuit can be traced as follows: main 9, front contacts B1, conductor 16, switch 24, valve 3, con- -`ductor 18, centrifugal switch 19, to the main 10. Accordingly, the main burner 1 is now ignited, establishing the main burner flame 8.
Should .it be desired manually to start the blower fan 15, the circuit controller `25, shunting the front contacts B2, may be utilized for that purpose.
A bimetal-actuated safety Warp switch, shown diagramatically, is arranged in such a way -as to ensure opening of the igniter circuit should there be a failure of the igniting system or in the event the pilot llame 7 fails after being established. The manner in which the system operates t-o effect this will now lbe described.
The safety warp switch includes a bimetal member 26 having a free end, shown end-on in the drawing. The free end may be arranged to move to the left in accordance with :the arrow 27 when the bimetal 26 is heated. A heater H is in heat-conducting relationship with the bimetal 26.
A similar bimetal member 23 is arranged -to move in the same direc-tion, as indicated by the arrow 29, when fthe bimetal member 28 is sufficiently heated by its heating coil l.
The bimetal member 26 carries brackets 32 and 33 appropriately mounted on the free end of the bimetal member 26. These brackets respectively support the opposed contact members 30, 31.
Similarly, contact members 34 and E35 are carried by the free end of the bimetal member 28. Normally these contact members 30, 34 are spaced apart, as well as the contact members 311 and 35. The distances between these contact members are purposely exaggerated in the figure. Nonmally they may be quite close together.
Should the bimetal member 25 be heated while bimetal member 28 is not heated, fthe contact member S1 will ultimately engage contact member 35, and a safety circuit is established. Should the bimetal member 28 be heated while the bimetal member 26 is not heated, the contact member 34 will engage contact member 30, and the same circuit will be established. However, should the two bimetal members 26 and 21S move to the left or to the `right substantially in unison, the circuit controller will remain open.
The bimetal members 26 `and 28 are included in the circuit lfor rel-ay A. The heater H for the bimetal member 26 has its circuit established through the front contacts B1 through a relatively high resistance 36 as soon as the relay B is energized and lthe centrifugal switch 19 is closed. The heater I, however, is not energized until the circuit controller 24 is closed due tothe establishment of the pilot flame 7. This circuit extends from main 9 to contacts B1, conductor 16, switch 24, heater J, high resistance 37, centrifugal switch 19 to the main 10.
Should there be a failure `of ignition, then the switch 24 will not close. Under such circumstances, the heater I is not energized. After an interval, dependent on the intensity of heat developed by heater H, the bimetal member 26 will move laterally to close the contacts. Under such circumstances, the relay A is energized. Immediately upon its energization, the contacts A2 open and the system is rendered inoperative because of the opening of the front contacts B1 and B2. Furthermore, a holding circuit for the relay A is established through the front contacts A1.
Assuming that the thermostat switch 5 continues to call for heat, the circuit is rendered inactive until manually reset by pushing the reset button 14 or momentarily lowering 4the setting of the thermostat. When this occurs, relay A drops out and relay B is energized through the back contacts A2. The process, at an attempt to activate :the system, starts all over again.
In the event the system is operating with the pilot flame '7 in existence, the failure of the pilot flame Will cause the circuit controller l to close and circuit controller `24 to open. This again opens the circuit for the heater I and energizes the electric igniter to re-establish the pilot flame, If the pilot ilame is not established in a predetermined time, the bimetal member 26 energizes relay A to render the circuit ineffective. Again the reset button 114 must be pushed or the thermostat setting momentarily lowered in ordertto start the system into operation.
Should either heater H or J burn out then the other heater will cause a circuit to be established between the bimetal members 26 and 2S, yshutting down the entire system.
The inventor claims:
l. In a safety system fora main burner and its pilot burner: an ignition circuit for the pilot burner; said circuit including a normally closed circuit controller operated to open posi-tion in response to the establishment of the pilot flame; `an electrically energized valve -for the pilot burner; means responsive to heat demand for opening the pilot burner valve and for completing the ignition circuit; means for opening the main burner valve upon establishment of the pilot flame; and means operative after a time delay, for rendering the system ineffective even while the demand for heat continues, in response to failure of the pil-ot flame, comprising a rst bimetal member; a heater for the member energized upon energization of the ignition circuit; a circuit control means having a pair of cooperating contacts, one carried by the bimetal member; a second bimetal member carrying the other contact; a heater for the second bimetal member and energized only when the pilot flame is established; said bimetal members being so arranged that they keep the contacts in such position, when both heaters are energized, that the system is kept in operation; and upon failure of either heater to produce heat, the system is rendered inactive.
2. In a system for controlling the operation of a main burner and its pilot burner, and includ-ing a m-ain burner valve, a pilot burner valve, an igniter circuit, and a switch responding to a demaind for heat for causing initiation of the system: a relay having a front contact and controlled by said switch; said front contact causing opening of the pilot valve, as well as energization of the igniter circuit; means responsive to the establishment of the pilot flame -ifor deenergizing said igniter circuit and for opening the main burner valve; and means operating upon a time delay for deenergizing said relay in response to the non-existence of the pilot llame, comprising a pair of bimetallic members; cooperating contacts carried respectively by the members and normally out of contacting relation; electric heaters for said members; and circuits for said heaters -for energizing them; one of said heater circuits responding to initiation of operation of the system; and the other heater circuit being responsive to the establishment of the pilot flame; said bimetal contacts closing upon a time delay when only one of said heater circuits is energized.
3. In a system for controlling the operation of a main burner and its pilot burner, and including a main burner valve, a pilot burner valve, an igniter circuit, `and a switch responding to a demand for heat for causing initiation of the system: `a relay having a front contact and controlled by said switch; said front contact causing opening of the pilot valve, `as Well as enertgization of the igniter circuit; means responsive 'to the establishment of the pilot flame for deenergizing said igniter circuit and for opening the main bu-rner valve; and means operating upon a time delay for deenergizing said rel-ay in response to the nonexistence of the pilot llame, comprising a pair of bimetallic members; cooperating contacts carried respectively by the members and normally out of contacting relation; electric heaters for said members; circuits tor said heaters for energizing them; one of said heater circuits responding to initiation of operation of the system; and the other heater circuit being responsive to the establishment o-f the pilot llame; said bimetal contacts closing upon a time `delay when only one of said heater circuits is energized; and a second relay energized through said bimetal contacts, for deenergizing said rst relay.
4. In a system for controlli-ng the operation of a main burner and its pilot burner, and including a main burner valve, a pilot burner valve, an ignitercircuit, and a switch responding to a `demand for heat for causing initiation of the system: a relay having a yfront Contact and controlled by said switch; `said front contact causing opening of the pilot valve as Well Ias energization of the igniter circuit; means responsive to the establishment of the pilot flame for deenergizing said igniter circuit and for opening the main burner valve; a pair of bimetal members in juxtaposed positions; electrically energized heaters respectively for the bimetal members; contacts respectively carried by said birnetal members; said bimetal contacts being normally spaced but ultimately engaging in response to unequal heating o the two bimetallic members; a second circuit for deenergizing said relay and controlled by lthe bimetal contacts; means responsive to the establishment of the pilot ame for energizing one of said heaters; and means .responsive to the initiation of operation of the sy-tem for energizing the other heater.
References Citaal in the le of this patent UNITED STATES PATENTS 1,863,443 Goodridge June 14, 1932 2,183,973 Raney Dec. 19, 1939 2,198,556 Cunningham Apr. 23, 1940 `2,227,291 Wittmann Dec. 31, 194() 6 McGrath May 13, 1941 Lockrae July 22, 1941 Petersen June 9, 1942 Scoggin Oct. 12, 1943 Kauman Feb. 2'6, 1946 Eskin et al. Mar. 26, 1946 Wilson Jan. 27, 1953 Mayer et al Aug. 18, 195'3 Geldhof et al. May 18, 1954 Dillman Oct. 26, 1954 Hotchkiss Nov. 8, 1955 Deubel Jian. 10, 1956 Hullar Jan. 6, ll959 Cobb Jan. 5, 19160 Deziel Feb. 9, 1960 Sager July- 12, 1960