US1679331A - Oil-burner control - Google Patents

Description

July 31, 1928. 1,679,331

w. w. WILLIAMS OILIBURNER CONTROL Filed March 11, 1925 2 Sheets-Sheet Waller MMY/fams 11v VENTOR July 31, 1928. 1,679,331

w. w. WILLIAMS 7 O IL BURNER CONTROL 7 Filed March 11. 1925 2 Sheets-Sheet 2 n e w M A l 77016 N E Y i an Patented July 31, 1928.

v UNITED STATES PATENT OFFICE.

WALTER W. WILLIAMS, BLOOMINGTON, ILLINOIS, ASSIGNOB. T0 WILLIAMS OIL-O- MATIC HEATING CORPORATION, OF BLOOMINGTON, ILLINOIS, A CORPORATION OF ILLINOIS.

OIL-BURNER CONTROL.

This invention relates to improvements in liquid fuel burning mechanism and more particularly to oil burner construct-ions for domestic purposes and safety controls.

To burn liquid fuel in the usual domestic coal burning furnace or heater an oil burning mechanism is provided on the outside of the furnace or heater'having an oil ipe and air conduit or pipe leading there rom 1 through or below the usual furnace door to the fire box and such devices are generally operated by an electric motor which drives a fan to supply both oil and air to the burner, however, some devices of this character use a gravity feed for supplying oil. The

flame of the burner is ignited either from a constantly burning pilot light or by an electric spark and the operation of the burner is controlled by a room thermostat or other means for cutting off the flame when the building to be heated reaches a desired temperature and again starting the burner when the temperature drops below a desired degree. A boiler or furnace control is also employed at times in steam and hot water or hot air systems which will act in the same manner as the room thermostat when the pressure or temperature within the boiler or furnace becomes too great and function as a safety device.

The room thermostat and boiler control thereforewill start and stop the burner intermittently and is a part of its normal operation. Should the flame at the burner fail or become extinguished while the oil supply is operating the fire box will become filled with gases, saturated with the oil and later overflow, if the oil supply is not cut oif, and further if the flame should reignite while the fire box is filled with gases or saturated with the oil an explosion orat least a puff will occur disturbing the occupants of the build- .ing and most probably doing damage to the furnace and burner construction. Various means have been devised to act as a safety device to cut off the oil supply upon extinguishing of the flame.

It is an object of this invention to provide a simple safety device actuated by the burner flame that will act positively to cut oil the oil supply in case the burner flame becomes extinguished, that is not affected by the normal operation of the burner in stopping and starting as actuated by the room thermostat or boiler control, that will operate very quickly upon the failure of the burner flame from abnormal causes, and when once operated requires but a simple Enanual operation to reset in operative posi- 101'1. While a preferred form of this invention is illustrated upon the accompanying sheets of drawlng, yet it is to be understood that minor detail changes may be made .without departing from the scope thereof.

In the drawings:

Figure 1 is a view in side elevation, with parts broken away and in section, illustratmg a form of this improved oil burner construction in place.

Figure 2 is an enlarged perspective detail view of the fire box end of the oil nozzle and air conduit.

Figure 3 is a detached detail view of the thermal bulb.

Figure 4 is an enlarged sectional View of a modified form of fire box end construction.

F1gure 5 is a detail view of the safety devlce panel, wall thermostat and a diagram of the wiring to the motor.

The burner mechanism illustrated includes a fan blower 1 driven by an electric motor 2 with an air conduit or pipe 3 leading through the wall 4 of the furnace into the fire box thereof, with an. oil pump 5 also operated by the motor 2 to force oil from a source of supply, such as a tank not shown,

through an oil pipe 6 arranged centrally within the air conduit having a discharge nozzle 7 located adjacent the fire box, all of which are of usual construction. This invention contemplates the utilization of the heat generated by the burner flame to actuate the safety device by arranging a sensitive thermal unit in proximity thereof and providing means which not only protects such thermal unit from the excessive heat generated in the fire box when the flame is burning but also insures its prompt action when the flameis extinguished or fails.

In carrying out this inventionthe safety device is interposed in the circuit between the burner mechanism motor and the commercial source of electricity and includes a switch in the motor circuit controlled by the heat generated by the burning of the oil at the nozzle to close the circuit and acting to break the circuit when the flame goes out, to-

gether with means allowing the normal operation of the room thermostat and boiler control, also in the motor circuit, to break and close the motor circuit without operating the safety switch.

The safety switch is controlled by the pressure generated in a pressure bellows or tube 8 causing the bellows or tube to expand or contract in accordance with the expansion and contraction of a thermal liquid enclosed in a sealed tube 9 communicating at one end with the switch actuating bellows or pressure tube and arranged to be affected directly liy the heat generated by the burner flame. t is preferable to enlarge one end of the tube or provide an enlarged bulb 10 in communication with the interior of the tube and place such bulb adjacent the burner so that when the flame is burning the contained liquid will expand rapidly beyond its normal volume causing the safety switch to be moved to-close the motor circuit and when the flame is extinguished to contract to normal and throw the safety switch to break the motor circuit.

In order to place the thermal switch operating bulb 10 in proximity of the burner flame and yet not be destroyed by the intense heat generated by the flame in the fire box of the furnace a. housing 11 is provided above the air conduit 3 at its fire box end and opening into the fire box directly above and in line with that end of the air conduit but closed upon the outer surface of the air conduit on the sides and other end. The thermal bulb 10 is arranged within this housing directly above the oil pipe nozzle 7 and as the housing is open towards the fire box this bulb is affected directly by the burner flame and temperatureof the fire box. The tube 9 leading from the bulb to the bellows or pressure tube 8 is preferably passed through the closed end of the housing to the bulb 10., as shown in Figure 1. As the walls of the bulb are of thin metal the continuous and intense heat communicated to it from the burner and fire box, while the burner is operating, would soon destroy or melt its walls. In order to prevent such action a portion of the cool fresh air forced throu h the air conduit by the fan is divertef and caused to pass continually about the bulb as long as the motor operates by providing a plurality of openings 12 in the air conduit walls under the bulb housin preferably some at a distance from the bu and nearer the fan and others at a shorter distance from the bulb. As shown by the arrows in Figure l, by this means the cool air under pressure continually passes about the walls of the bulb and will keep its temperature below that of destruction while the urner flame is burning and, furthermore, whenever. the burner flame is extinguished and the fire box is heated, the cool fresh air passing about the bulb will reduce its temperature much more rapidly than the falling of the temperature of the fire box.

By this construction of the fire box end of the air conduit which diverts part of the air passing therethrough on its way into the fire box it makes it possible to locate a very sensitive safety control thermal element in close proximity to the burner flame which will quickly actuate the safety device whenever the burner fails from abnormal causes.

A modified construction of the housing 11 and fire box end of the air conduit 3 is shown in Fi re 4. In this form the openings in the air conduit walls under the housing are omitted and the rear wall 13 of the housing is provided with a supplementary air conduit or pipe 14 leading from the interior of the housing which may be connected at its other end to the blower fan casing adjacent the fan or to a supplemental fan blower or other source of air current not shown. If desired the end 13 of the housing may be omitted altogether so that the housing is open at both ends allowing a current of cool atmospheric air to be inducted therethrough by the current of air forced through the air conduit 3 from the fan blower when the motoris operating or sucked in therethrough by the current generated in the firebox by the heat therein ascending throu h the furnace flue, not shown, whenever t l ie burner becomes extinguished.

It is immaterial whether the burner flame is ignited in the normal, operation of the burner by an everburning pilot light or by an electrical ignition system, although the drawings illustrate an electrical ignition comprising a spark coil, preferably con- .tained in a box or casing 15-upon the motor casing with wires leading to "the electrodes 16 and 17 to form a spark gap in proximity of the oil discharge nozzle 7, which spark gap is greferably arranged on the fire box side an just above the discharge opening of the nozzle, as shown.

The form of safety switch cooperating with the thermal element above described is preferably arranged on a panel 18 in a box or casing 19 attached to the fan blower casing 1, as shown in Figure 1. The panel is illustrated in detail in Figure 5 in connection with a diagram of a preferred form 'of wiring. The pressure bellows 7 is illustrated on this view with the thermal liquid containing pipe 9 leading from one side thereof through the side walls of the casing and is arranged with that end of the bellows stationar The other and movable end is connecte to one end of a pivoted operating lever 20 the free end of which, on the other side of its pivot, is connected by a pivoted link 21 to a rocking frame 22 carrying a mercury 'tube switch 23 having electric terminals 24 and 25 entering the tube. at or ible leads'26 to binding posts 27 and 28, re-

spectively, on the panel, which in turn are connected to binding posts 29 and 30, respectively, adjacent the top of the panel, a shown. I

Another similar mercury tube switch 31, having electrical terminals 32 and 33 likewise located at or adjacent one end of the tube and similarly connected by flexible leads 34 to binding posts 36 and 37, respectively, adjacent the top of the panel is carried in a rocking frame 38 mounted on thepanel. This frame 38 is provided with a counter weight 39 at one end, to normally depress that end of the tube and break the circuit through its terminals 32 and 33, and

' with a catch member 40 extending from the other .end. A strip 41 of thermal metal 'is supported at one end below the catch member 40 having a lip at its upper free end adapted to be free of the catch 40 under nor- 'mal temperatures. A heating element 42 is arranged adjacent the thermal strip 41 which when in circuit will increase the temperature of the strip and cause it to bend or move toward the rocking frame 38 so that the lips will engage the catch and hold .the counter weight from breaking the circuit through the tube switch 31. The heating element is here shown as an electric lamp, though it maybe any other form of electric heating element, with one terminal connected by a lead to binding post 37 and the other terminal by a lead to binding post. 29.

When the switch is closed to place the burner operating mechanism in circuit with the main lines, A and B of the source of commercial electricity, its normal operation is controlled by the room thermostat of commercial design having a rocking mercury tube switch 43 with two sets of terminals 44 and 45 near each end so that when the switch is rocked to lower one end the mercury will close the circuit through the lower terminals breaking the connection between the other pair and vice-versa. The thermostat is provided with three binding posts 46, 47 and 48 with flexible leads 49 from the outer binding posts 46 and 48 to the outer terminals of the sets 44 and 45 and two flexible leads from the intermediate bin'ding post 47 to the adjacent terminals of each being connected to binding post 48 of the.

thermostat and the binding post 47 is connected through switch S to line B. Binding post 29 of the panel is connected to binding post 46 of the thermostat T and binding post 30 of the panel is connected to the line leading from binding post 47 to line B. a 7

Before switch S is closed no current passes through the burner operating mechanism and the fire box will be cold but the room thermostat will be normally actuated by the temperature of the building. The heating element or heat generator 42 being out of circuit will release the safet tube switch 31 which will assume the position indicated in dotted lines, andthe thermostat bulb 10 being cool the bellows 8 will have actuated the tube switch 23 to assume the position shown in dotted lines. The thermostat tube switch 43 will be in either the dotted line or full line position depending upon the atmospheric temperature.- Assuming the thermostat tube switch 43 is in the position shown in full lines when switch S is closed, then the circuit through the thermostat and motor will be broken between binding posts 36 and 37, as tube switch 31 is in open position, and the motor will not operate. Therefore, it is necessary to close the safety switch 31 by hand and hold it for a short time until the lip of the strip 41 engages the extension 40, as hereinafter described. 7

Upon manually tilting the tube 31 to close the circuit therethrough and through binding posts 36 and 37 the motor is placed in circuit and will operate the oil pump, to supply fuel to the burner nozzle, and the fan blower, to force air through the air conduit, to form the burner mixture and the electric ignition or pilot light will ignite the burner flame. The ignition of the burner flame will immediately impart heat to the thermal bulb 10, even before the heat in the fire box does .so, which causes an expansion of the thermal fluid therein to cause the bellows 8 to expand and throw the tube switch 23 into the closed position, as shown in full lines. In this position a circuit is completed through binding post 37, heat generator 42, binding post 29, switch 23, binding post 30 and main lead B. The heat from the heat generator 42 will cause the.thermal strip to expand so that its lip will engage over extension 41 and 'hold the safety tube 31 in closed position. It is therefore necessary to manually hold the safety switch in closed position until caught by the lip, when inistruction of the parts in accordance with this invention, so sensitive that the thermal strip 41 will be actuated to hold the safety switch in a few seconds, and it will take but an inappreciable time to set the safety switch.

, Should the temperature of the room cause the temperature to rock the tube switch 43 to the position indicated in dotted lines the circuit through the motor will be broken between binding posts 47 and 48 and at the same time close the circuit between binding posts 46 and 47 which maintains the heat generator 42 in circuit from line A through binding posts 36, 37, 29, 46 and 47 to line B. Upon the breaking of the motor circuit in this manner the supply of fuel oil and air ceases and the burner flame becomes extinguished. The thermal bulb 10 then operates the bellows to rock the tube switch 23 to break the circuit between binding posts 29 and 30 but the current will still operate the heat generator 42 by the way of binding posts 29, 46 and 47 so that when the atmospheric temperature causes the thermostat switch 43 to rock back to the position shown in full lines the circuit through the motor will be completed at the same time the circuit is broken between binding posts 46 and 47 and the burner flame being ignited at the same time it, through bulb 10, will cause the bellows 8 to close the circuit between binding posts 29 and 30 to include the heat generator 42 in that circuit before the thermal strip 41 will have time to cool and contract sufiiciently to release the safety tube extension 40. Therefore, it is seen that the normal operating of the thermostat after the burner has been initially ignited and safety switch set by hand does not actuate the safety switch on account of the rapid actuation by the bellows 8 in closing the circuit through the tube switch 23.

On the other hand, should the burner flame fail or become extinguished during the normal operation of the burner and thermostat, the rapid cooling of the thermal bulb 10 will cause the breaking of the circuit be- 7 tween binding posts 29 and 30 which, as the thermostat must be in the position shown in full lines to have caused the burner flame to be burning at the time it failed, will immediately break the circuit between binding posts 29 and line B so that the heat generator 42 is out of circuit and will allow the strip 41 to cool and contract sufficiently to release the safety switch tube 31 to be rocked by counter weight 39 to break the circuit between binding posts 36 and 37 so that the motor can not be started again until the safety switch is again rocked by hand and the operation of the heat generator 42 to maintain the safety switch in closed position and as long as the burner operates under normal conditions the operation of this room thermostat breaks one circuit through the heat generator as it closes another circuit through it, except that when the thermostat operates to close the circuit through the motor the heat generator 42 is out of circuit until the thermal bulb 10 closes the circuit through the switch 32 actuated by it. Also upon the failure of the burner flame from abnormal causes the circuit through the heat generator 42 is broken by the bulb 10 actuating switch 23 to break the circuit. By producing means to actuate the switch 23 to close or break the circuit therethrough sensitive enou h to require but a few seconds after the urner flame has been ignited or extinguished, the short space of time between the actuation of the thermostat switch 'to break the circuit through the heat enerator 42 and close the circuit throug the motor and the actuation of the switch 23, by the ignition of the burner flame, is not suflicient to allow the thermal strip to cool and contract sufliciently to release the safety switch and the same sensitive means upon the failure of the burner flame from abnormal reasons causes the safety switch to break the motor circuit in a few seconds after the flame has been extinguished.

What I claim is:

1. In a liquid fuel burner construction having an electrical operating means therefor and a room thermostat in circuit therewith controlling the normal operation thereof, in combination with a safety device in said circuit requiring a manual setting to close the circuit, means actuated by the passage of the current therethrough to hold the set osition, and additional means in circuit with said holding means and operating circuit, independent of the thermostat, controlled by the heat generated by the burner flame and adapted to break said circuit upon failure of said flame, said thermostat having means operable upon breaking the operating circuit to simultaneously close the circuit through the safety device, and holding means.

2. In a liquid fuel burner construction having an electrical operating means therefor and a room thermostat in circuit therewith controlling the normal operation thereof, in combination with a safety switch normally open and adapted to close said circuit by a manual setting, a heat generator in circuit with said safety switch, a thermal element actuated by the passage of the current through said heat generator to hold the set position, and additional means in circuit with the safety switch, heat generator and source of electricity controlled by the heat of the burner flame to close said circuit and upon failure of said flame to break said circuit, said thermostat having means operable upon breaking of operating circuit to simultaneously close circuit through the safety switch, and heat generator.

3. In a liquid fuel burner construction having an electrical operating means therefor and a room thermostat in circuit controlling the normal operation thereof, in combination with a safety device in said circuit requiring a manual setting to'close the circuit, means actuated by the passage of the current tl'ierethrough to hold the set position, and additional means in circuit with the holding means and source of elcctricity comprising a switch and a control therefor, and a thermal element actuated by the heat generated by the burner flame for operating said control to close said circuit and break said circuit upon failure'of said flame, said thermostat having a means operable upon breaking the operating circuit to simultaneously close the circuit through the safety device, and holding means, to the source of electricity.

4. In a liquid burner construction having an electrical operating means therefor and a room thermostat in circuit therewith controlling the normal operation thereof, a safety switch normally openv adapted to close said circuit by a manual setting, a thermal element actuated by the passage of current through a heat generator in circuit with the safety switch, to hold the set position, and an additional switch in circuit with the heat generator and source of electricity, a control therefor having a thermal element adjacent the burner nozzle actuated by the heat of the burner flame to operate the con-- trol to close the circuit through said additional switch and upon failure of the, flame to break the said circuit, said thermostat having means operable upon' breaking the operating circuit to simultaneously close the circuit through the safety switch, and heat r generator to the source of electricity.

' 5. In an oil burner construction, an electric motor operating an oil pum and blower fan, a rocking tu'be safety switc adapted to be manually rocked to close the circuit between the motor and source of electricit having means normally rocking it to brear said circuit, a thermal member adjacent the closed position of said rocking safety switch, a heat generator ada ted to be energized by the closing of the sa ety switch to cause the thermal member toexpand, engage and hold the safety switch in closed osition, an additional rocking tube switch iiaving one terminal connected through the heat generator to one terminal of the safety switch and the other to the source of electricity, :1 thermal control actuated by the heat from the burner flame to rock the additional switch to closed position and close the circuit through the safety switch, heat generator and source of electricity and upon failure of the burner flame to rock the additional switch to break said circuit, and a room thermostat controlling the normal operation of the burner mechanisi'n including a rocking tube switch having two terminals at each end, the outer terminal at one end connected to one terminal of the motor, the inner terminals at each end connected to the source of electricity and the outer terminal at the other end con-' nected to one terminal of the heat generator, the other terminal of the motor connected to one terminal of the' safety switch, Whereby with the thermostat switch 'in one position the circuit is completed through safety switch, motor and thermostat with a shunt from safety switch through heat generator and additional switch tosource, and in the other position-of the thermostat switch the circuit is completed through safety switch, heat generator and thermostat.

6. A safety control for an electrically operated oil burner having a room thermostat switch adapted to make and break the circuit on one side of the motor, a safety switch in the circuit on the other side of the motor provided with means to normally move tor, thermal actuated means at normal temperature operating to open said additional switch and actuated by heat generated by the burner flame to close the circuit through safety switch, heat generator, additional switch to source, said room thermostat switch normally operating to break the motor circuit and simultaneously close the circuit through the safety switch and heat generator in one position, and in the other porition to close the circuit through safety switch and motor and simultaneously break the circuit through the heat generator, said thermal actuating means operating the addi tional switch in time to close the circuit through the heat generator, additional switch and source before the safety switch thermal holding means has released the safety switch during the normal operation of the room thermostat.

WALTER W. WILLIAMS.

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