US1780971A - Safety-control mechanism for fuel-burning devices - Google Patents

Description

Nov. 11, 1930. c. B. CHANDLER SAFETY CONTROL MECHANISM FOR FUEL BURNING DEVICES Filed July 5l 1925 5 Sheets-Sheet l fwuewwk Nov. l l 1930. c, B, CHANDLER 1 1,780,971

SAFETY CONTROL MECHANISM FOR FUEL BURNING DEVICES' P Filed Jul 21,1 2 s Sheets-Sheet 2 Nov. 11, 1930.

1 c. BCHANDLER SAFETY CONTROL MECHANZSM FOR FUEL BURNING DEVICES 5 Shets-Sheet Fild July :51, 1925 ugs:

Patented Nov. H, 193

unit 'raras ATENT care CAB/L B. CHANDLER, F HAVANA, ILLINOIS, ASSIGNOR TO HAVANA METAL WHEEL (lO., OF HAVANA, ILLINOIS, A CORPORATION OF ILLINOIS SAFETY-CONTROL MECHANISM Application filed July 31,

My invention relates to automatic fuel burning devices and more particularly to safety control means therefor.

One of the objects of my invention is in the provision of electrical safety control mechanism for fuel burning devices, operating to prevent energization of the burner immediately after cessation of normal operation.

Another object of my invention is in the provision of electrical safety control mechanism for automatic fuel burning devices, adapted to prevent the projection of fuel mixture into the combustion chamber when 5 said combustion chamber is at a temperature sufficient to cause an unnatural ignition of the fuel mixture.

Yet another object of my invention is. in the provision of electrical safety control mechanism adapted to prevent the burner from operating too frequently and for too short intervals.

Still another object of my invention is in the provision of electrical safety control mechanism that prevents the immediate commencement of operation of the burner after a so-called surge on the line. A further object of the invention is in the provision of a fuel circulating chamber having a float control connection with the electrical circuit, and adapted to automatically cut out the burner upon a failure of fuel flow or upon overflow of the fuel.

Other objects of my invention will appear .in the following specification, taken in connection with the annexed drawings, in which- Fig. 1 is a side elevation of the fuel burning device, or rather the mechanical portions thereof, showing the manner of installation in the combustion chamber, as well as the assembly of the portions removed from the combustion chamber.-

Fig. 2 is a vertical sectional view show- 46 ing in detail the arrangement of the circulating chamber, and spark timing mechanism and safety mechanism in connection with the fuel supply.

Fig. 2A is a view with no sections re-.

Z 50 moved showing the right hand upper corner FOR FUEL-BURNING DEVICES 1925. Serial No. 47,188.

of Fig. 2, the contact button in contacting position.

Fig. 3 is an even more complete detail showing of the automatic fuel control mechanism, and

Fig. 4 is a view showing diagrammatically the electrical circuits included in the device.

Before referring to the drawings for the purpose of description, it might be said that the fuel burning device disclosed in the present instance is merely of a type developed and manufactured by applicant, and that any of the numerous types of fuel burning devices might as well be disclosed, inasmuch as the subject-matter of the present invention is directed to the safety control features' and could be applied to any class of fuel burners.

Again, with respect to the objects of the present invention, it might'be said that the well known and so-called domestic fuel burners of today are automatically controlled, this word automatic referring in the trade to fuel burning devices used for heating purposes and located ordinarily in the formal furnace of the home, said fuel burning devices having their operation controlled by a switch mechanism controlled by a thermostat sensitive to temperature conditions located at some point in the house or structure that is to be heated. In other words, the temperature of the house controls the activity of the burner, and'no manual effort is necessary under normal and natural conditions.

There are many advantages in the fact that these burners are now automatically controlled, but one disadvantage remains, which would not and did not attend the use of manually controlled burners. This disadvantage or weakness of the automatic burner has to do with its safety, as there is no person present when the device starts its operation, or as a matter'of fact, at any time during the operation of the burner. Specifically whether the burner started and whether it was properly ignited. He would be able to determine whether it would be safe to start the present invention.

burner, having in mind at this time, whether the furnace, or rather the combustion chamber thereof, was at a high temperature and ca pable of causing an unnatural ignition ofthe fuel mixture projected thereinto. In the present case, I deal with the safety feature above referred to, namely, the possibility, in' an automatically controlled burner, of projecting a fuel mixture into a hot furnace. However, other advantages also attach to the type of safety control as set out in the objects of the It is well known in the trade that .with the projection of the normal fuel mixture into an excessively hot furnace, an unnatural ignition will many timestake place, the same being nothing more nor less than an explosion, whether it be called a puff or flareback. The blowing off of the doors of furnaces, and

in many instances, the wrecking of same, and

even the burning of houses, has been caused 25 by just this Weakness in the automatically controlled burner, since ,the automatic feature took away the safeguard of manual presence. As said before,'it is the object of the applicant in the present instance to provide mechanism that safeguards against any such accident, as well as to provide other advantages coincident with said mechanism.

, Referring to the drawings, I have shown in Fig. 1. a fuel burning device of the so-called rotary cup type, whereinan atomizing cup 10 is driven by a formal electric. motor 11, through friction mechanism, generally referred to as 12, the-cup memberbeing mounted upon a shaft 13, supported in suitable bearings, etc. Means for supplying fuel to the atomizing cup 10 is provided in a pump member 14, driven by the electric motor 11, said pump withdrawing fuel from'a circulating fuel chamber 15, through a pipe 16,, and delivering fuel to the atomizing cup through the pipe 17 past a control'valve 18, thence through pipe 19, and finally to the jet. 20,, said jet delivering directly into the rotary cup member 10. A by-pass for excess fuel is taken care of in a manner to be later described, inasmuch as this by-passed fuel is sparking mechanism or electrode 21 located adjacentthe periphery of said cup.

Again, referring to the circulating fuel chamber, I find said chamber supplied by gravity from a large storage tank ("not shown), located usually at a. distance fronr said chamber, and at an elevation slightly said float member having a spring tensioned sliding connection 26 with the formal valve 27 controlling the flow of fuel through the pipe 22. This spring tension sliding connection 26 permits lowering of the float member to open the valve, as well as .the closing of the valve upon the proper fuel level being reached, with still a possibility of upward movement of the float in case the chamber should receive an oversupply of fuel due to some accident, for instance sticking of the valve 27.

Mechanism later to be described in connection with ,the electrical circuit of the device is controlled by the movement of this float member to effect stopping of'the burner in case'of a failure or overflow of fuel in the circulating chamber.

Now, with respect to the by-passing of unused fuel by the needle or control valve- 18, I find said fuel passing through the pipe 28 and thence into a passageway '29 having exit-through restricted openings 30, 31 and 32, to an auxiliary chamber 33, a float-chamber 34 and a return pipe 35 respectively.' The by-passed fuel, in other words, has a possible flow into the float chamber, the auxiliary chamber and the return pipe, with the result. that the gradual filling of the float chamber 34 causes the float member'36 t-herein to be raised. Upon the float member 36 attaining its highest elevation in the float chamber, the fuel occasioning such rise will then overflow through the port 37 into the return pipe 35, and thence to the circulating chamber 15. The movement of the float 36 is utilized to move the formal mercoid switch member 38 from a closed to an open position, this movement being affected through a stem 39 attached to the float meni-- ber, said stem having the spaced lugs 40 providing attachment means for-the lever arm ,41 controlling the movement of the bulb 38 containing theformal contacts 42- and mercury 43 therein.

It might" be stated at this time'that al. though the electrical circuits have notyet been traced, the raising of this float member and the opening 'of an electrical circuit, due

to the movementof the before-described levers, operates to stop the sparking of the tating cup, the samebeing accomplished at a suitable and determinable time afterthe initial commencement of operation of the burner. I f

Also the. raising of this float member simultaneously controls another electrical contact through the extension of the stem 39, and.

electrode adjacent the periphery of the roits operative engagement with the spring tensioned contact member 44 and strip 45.

To more fully describe the operation of the float in connection with these contact members, which provide the safety control means, it might be saidthat the lug 46 upon stem 39 operates when the float is in its lowered position during inactivity of the burner to hold the contacts 44 and 45 together, in other words, in a closed position. Following upon the initial upward movement of the float chamber, the spring tensioned contact 44 is permitted to move away from the stationary contact 45, hence immediately open ing the circuit therethrough. In order that the flort 36 may be lowered, the -oil in the chamb rs 33 and 34 may pass through the restricted opening 32 into and down the return pipe 35. Some of the oil may also return through the pipe 28.

' To further describe the physical structure, without including its connection in the electrical circuit, which will be described later, a rod 47 is attached at 48 to the lever 25 of the float member, said rod extending through the return pipe 35 and eventually passing through a ferrule 49 and contact button 50. A lug member 51 is attached to the projecting end of said rod and another lug 52- is attached to said rod at a point just below the ferrule 49. This ferrule 49 has a slight frictional connection with an insulated plate member 53 suitably attached to a supporting frame 54 mounted upon the upper end of the float chamber. The button is grasped upon its concave sides by opposed tensioned contact members 55 and 56, hence providing a knock-out switch adapted to be controlled by the movement of the rod member 47 Obviously, a lowering, or rather absence of fuel in the circulating chamber 15 will result in the downward movement of the float, hence a downward movement of the rod 47 with the result that the lug 51 will abut the button 50, and finally force it from its spring tension engagement withthe contact members 55 and 56, thus. opening the electrical circuit therethrough. Similarly, an overflow of fuel in the circulating chambe'r'will result in the upward movement of the-rod 47 with a consequent abutment of the lug 52 against the lower end of the ferrule 49 with a resultant upward movement of the ferrule and consequent displacement of the button 50, as shown in Fig. 3, thereby opening the electrical circuit through said switch.

Turning to Fig. 4 of the drawing, I find a diagrammatic lay-out of the electrical circuits making up the automatic feature of the burner. In this view, the electrical circuits areshown in connectlon with the physical portions of the burner so that it may be readily understood just how the safety mechanisms acutally operate. It might also be said that generally the arrangement of elec-- trical wiring is substantially that used in practically all automatic oil burning structures, wherein a high and low voltage circuit is used. In view of the fact that this method of electrical wiring is in general use, I have shown my safety mechanism in connection therewith.

Although, as said before, the electrical circuits are almost formal, they will be described in. detail. The motor, previously described as 11, uses a high voltage current, usually 110 volts, and the 110 volt wires are appro'-- priately marked 110, the line connections from the street being marked L. A formal switch member has been designated S, and

is of the manually operable type. The 110 volt circuit as shown, leads first through a relay directly to the motor, as well as to a spark coil 57, which furnishes current to the sparking device 21, previously described, through the wires 110. It might also be noted at this time that this high voltage current to the sparking device is adapted to be interrupted by the opening of the circuit through the switch member 38, the same being operated by the-by-passed fuel also described.

Although in the present instance, a sparking device operating on a high voltage current is used, it is obvious that such sparking device might readily be used in connection with a low voltage current, similarly adapted to be opened by operation of a formal switch member controlled by the by-passed' fuel.

The relay switch controlling the high voltage or 110 volt circuit, is shown at 58, and this makes or breaks the 110 volt circuit and hence starts or stops the operation of the fuel burning device and portions operatingsimultaneously therewith. The means directly con trolling the operation of the relay switch 58 and hence starting and stopping of the.

fuel burning device are a formal room thermostat shown. at 61 and a so-called pressurestat usually located on the boiler of the furnace described as 62. The room thermostat located in the dwelling to be heated is sensitive to temperature conditions, and is switch, later to be described, and thence set usually to operate within a few degrees. r

In other words, if the temperature of the dwelling goes. down to the low point, the burner goes on, and after the dwelling has been heated to a temperature a few degrees higher, the burner goes OK, the movement of the room thermostat either energizing or deenergizing the magnet in the relay to open or close the high voltage circuit. The pressurestat, or more commonly called boilerstat,

is also in the low voltage circuit with the room thermostat, and is the nature. of a safety guard to shut off the burner in case boiler pressure becomes too high. In other words, even though the dwelling temperature was below the normal high point, and the burner running, the pressurestat would shut it off, if the boiler pressure was above a safe om p In describing the wiring in the low voltage circuit, this wiring will be referred to in the terms normally used in the trade, there being three main wires in the low voltage circuit, namely, the red wire, the white wire and the blue wire. When the temperature of the room is below the point set on the room thermostat, contact is made between the blue and white wires at the screw point 63 shown on the thermostat. This will energize the magnet and cause the arm to go forward against the magnet, making contact on the 110 volt line at points ZZ which I have indicated, and also making contact at X, which connects the red wire so that when the blue wire is broken by my safety switch 44 mounted above the spark timing device, the burner will continue to run, the circuit or shunt through which the current flows comprised of the red and white wires. The white wire is always connected except when broken by the room thermostat or the button throw-out switch 50. In other words, the blue wire is a starting wire and there must be contact made between the contacts 44 and 45 before the burner will start, and following, when-' ever the burner is stopped, it cannot be started thereafter until the float member 36 has returned to its lowermost position, thereby again making contact between the points 44 and 45 and closing the circuit in the blue wire.

As explained before, theobject of the present invention is to prevent in any manner thecommencement of operation of the burner after an initial cessation, at least for alpredetermined period. This period of time in the present structure, is determined by the time the float member will take to return from its topmost position to its lowermost position. Mere mechanical changes in structure may vary this interval although with the structure as disclosed herein, at least five minutes will be taken for the by-pass fuel to flow I out of the auxiliary chamber 33 and the float chamber 34. By lengthening the float chambers obviously a longer intervalof time may be readily had.

With the above described structure, any surge upon the line will prevent further operation of the burner until this time interval has elapsed. Likewise, any shutting off of the burner when the combustion chamber is at an exceedingly high temperature will result in the impossibility of turning the burner on either manually'or by room thermostat or pressurestat action until this interval has elapsed which will be sufficient to' permit a slight cooling of the furnace and such cooling as will prevent an unnatural ignition or explosion of the fuel mixture that is projected into the combustion chamber thereafter.

In Fig. 4 it may be also seen that the white wire includes the fuel safety throw-out switch. In other words the button switch 50 is included therein in such manner that should the fuel supply fail or should there be an overflow thereof then the rod member 47 would operate, through its lug members, to force the button 50 from between the contact strips 55 and 56, thereby cutting out w the burner and preventing further operation thereof until manual re-setting of said button switch was effected. 30

In view of the detailed disclosures and description of the operation of the safety mechanisms throughout the specification, no further description of the operation of the burner is thought necessary.

What I claim is:

1. In a fuel burning device, comprising an electrically operated means for projecting an atomized fuel mixture into a zone of ignition, safety control mechanism for delaying the energization of the burner after cessation of operation for a substantial interval of time, including a'main electrical circuit containing therein the said electrically operated means, a relay for opening and closing said main circuit, a secondary circuit for actuating said relay, a switch member therein normally closed to permit commencement of operation of the burner, a third circuit having a connection with the relay and being closed thereby simultaneously with the main circuit, whereby said switch member may be opened thereafter without stopping the burner, a float mechanism controlled by the accumulaton of fuel induced by burner activity, and a connection between the float mechanism and switch member capable upon movement of the float caused by the fuel accumulation induced by burner activity of opening said switch and thereafter holding same open until the float has moved to its subsided position upon the cessation of burner activity.

2. In a fuel burning device, comprising an I electrically operated means for projecting an atomized fuel mixture into a zone of ig-nitlon, a main circuit for controlling said electrically operated means, safety control mechanism for preventing immediate re-ignition' of the burner following a cessation of activity, including a relay for opening and clos-. o ing said main circuit, a secondary or starting circuit for the burner having a switch member therein controlling the closing of said main circuit by the relay, thereby controlling the commencement of operation of 125 the burner, a shunt on said secondary circuit having a connection with the relay and being closed thereby simultaneously with the main circuit, whereby said switch-member maybe .opened following said activity without stop- 130 ms e'ri ping "the burner, means for holding said switch member in an opened position during activity of the burner including a float mechanism controlled by the fuel accumulation induced by burner activity, said float member operating when movedby the fuel accu mulation to open said switch and thereafter" to maintain the same in an open position until the fuel accumulation stops and the float has subsided to its normal position.

3. In a device as defined by claim 2, a tem perature responsive mechanism in said shunt,

said temperature responsive mechanism con trolling the making and breaking of the cir- .cuit in said shunti In testimony whereof, I have hereunto afiixed my name- CARL B. CHANDLER

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