US1569994A - Thermostatic control device for fuel burners - Google Patents

Description

D. R. MARTIN THERMOSTA'IIC CONTROL DEVICE FOR FUEL BURNERS Filed Feb.

INVENTOR; For) 1?. Mar/1'27.

ATTORNEY.

Patented Jan. 19, 1926 m 'aps DORE R. MARTIN, OF DETROIT, MICHIGAN.

THERMOSTATIC CONTROL DEVICE FOR FUEL BURNERS.

Application filed February 3, 1922. Serial No. 533,855.

' To all whom it may concern Be it known that I, Donn R. MAIETIN, a citizen of the United States, residing at Detroit, county of \Vayne, State of Michii form a part of this specification.

This invention relates to control devices for fuel burners, and the principalobject of the invention is to provide means in conjunction with a thermostat for varying the intensity of the flame ofthe burner of heating plants whereby a room temperature may be maintained between' certain high and low limits of temperature, the thermostat being utilized to increase or decrease the flame of the burner corresponding to inverse variations in the room temperature influenced by the burner. Various heating appliances having burners have been used utilizing kerosene, fuel oil or gas as the heating element. In such former devices the oilor gas is discharged under pressure to the burner and sometimes air. or steam pressure isused with the oil to produce the desired character'of flame. In either of such former devices the pressure or volume of the oil flow may be varied or the pressure or volume of air and oil or steam and oil may be varied or the volume of flow of gas may be varied to vary the intensity of the flame of the burner, and it is to be understood that this invention may be used with any of such burners, and that the control valve may be placed as is found necessary or desirable to control the fuel flow in a .manner to vary the flame in tensity. With a house heating system for instance, the burner is usually employed with a steam heating device and as the room temperature increases, my control de vice tends to decrease the intensity of the flame and, as the room temperature falls,

the apparatus operates to increase the flame intensity, and it is to be understood that 1 variousdevices may be utilized in conjunction with a thermostat and control valve of the burner to vary the flame. Another obect of this invention is to provide an electrical d i e 99etr911edby a h m t t an adapted to vary the intensity of the heat of the burner inversely to variation in the room temperature. An additional object of the invention is to provide an electrical device for controlling the valve of the fuel supply line to vary the volume of flow of fuel supply to the burned to vary the intensity of the heat thereof. Further objects of the invention are involved in'the struc tural features and arrangements of parts as hereinafter more fully described and claimed, and the preferred form of construction of a device embodying my invention is indicated in the accompanying drawing which is a view partly diagrammatic in form showing my improved control apparatus and thermostat and indicating a burner and supply line therefor.

The burner may be of any approved type of'oil or gas burner, one type of which is indicated at l'having a supply line or con duit 2 for a fluid fuel. The burner has a dischar e nozzle and out of the forward end 3 '0 the burner, flame is projected as indicated by dotted lines. It is to be understood that the burner is applied to a heating appliance (as for instance a steam furnace not here shown), but by means of which a room or building is to be heated. In the supply line 2 is provided a valve 4 having an operating lever 5 therefor which may be turned to decrease or increase the volume of flow of fuel. It is to be noted that I have herev shown the conduit 2 as being a fuel line. Many burners are provided with a fuel line and an additional air or steam line, and the valve for controlling the intensity of the flame may be in the air or steam line by variation of the volume of which the amount of actual fuel or intensity of the flame of the burner may be varied. With the conduit 2 here shown, oil under pressure is to be considered as bein discharged to a burner therethrough an the valve 4, through manipulation of the lever 5, is utilized to vary the volume of flow of fuel from nothing to the fuel capacity ofthe line 2.

The thermostat is indicated diagrammatically at 6 and should be of a character to move the contact point a considerable extent for each degree or part of a degree of change in temperature, and I have devised a successful structure for this purpose which consists of a strip of iron and a strip of hard rubber secured together,

Hard rubber has a very high coeflicient of expansion while the metal strip has comparatively low coeflicient of expansion so that a slight change of temperature causes a considerable movement of the contact element. Other structures may be used if desired to secure'the desired range of movement of contact point. By such arrangement the contacts 8, 9, 10 and 11 may be placed a considerable distance apart. lVith a strip of hard rubber and soft iron as mentioned, twelve inchesin length, the spacing of the contact points 8 to 11 inclusive may be about three-eighths of an inch center to end of the shaft is connected by means of a link 14 with. the end of the lever 5 and longitudinal movement of the shaft, caused as hereinafter stated, actuates the lever 5 to control the valve between full open or closed position, such movement of the lever 5 being indicated by dotted lines in the drawing. At the forward end of the casing 12 are positioned four coils, 15, 16, 17 and 18 providing solenoids with central apertures thereof in alignment. The solenoids lie end to end and a core 19 is provided on the shaft 13. The core 19 is of soft iron and the shaft 13 should be of brass or non-magnetic material. The shaft'is also provided with a series of notches 20, 21, 22 and 23 corresponding to the number of solenoid coils and in these notches is normally projected a latch 24 projected downwardly into the notch by a spring 25in a solenoid case 26 on the upper side of the casing 12. This shaft 24 carries a core 27 which is common to four solenoids 28,29, 30 and 31 that are in com centric relation, the core being movable on the axis of the several coils. There is a circuit for each of the solenoids 15, 16, 17 and 18 which consists respectively of the lines 32, 33, 34 and 35 running respectively to the contacts 11, 10, 9 and 8 heretofore mentioned. The source of energy is indicated as a battery 36 connected directly to the thermostatic element in the structure here shown by a line 37 and the return line of the solenoids 15, 16, 17 and 18 is indicated at 38, 39, 40 and 41 connecting by a common line 42 with the opposite side of the battery. It is first to be noted that contact of the point 7 of the member 6 with the contact 9 of the line 34 will energize the coil 17 and draw the core 19 to the position shown in the drawing in which position the valve 4 is partly open and under which condition a certain intensity of flame is produced determined by the volume of fuel permitted to pass the valve4. If the flame and the heat developed in the room by the heating appliance to which the burner is applied is not sufficient to prevent a drop oftemperature in the room, the thermostat will continue to move toward the right and engage the contact 10 for the line 33 which will energize the coil to draw the core 19 and shaft 13 to the right of the position shown in the drawing increasing the opening of the valve and correspondingly increasing the intensity and heat of the burner. Each of the circuits 32, 33, 34 and 35 have a make and break switch 43 located within the casing 12 and this may conveniently consist of a contact 44 which is held in fixed position by a stud 45 and on this stud normally insulated from the contact bar 44 is a spring contact bar 46 having a lug 47 which normally rides on the surface of the shaft holding the contact points between the members 44 and 47 closed. Each line 32, 33, 34 or 35 is connected to the member 46 of its respective switch and continues with the member 44 of-the respective switch. Thus when these contact points 47 ride on the surface of the shaft,

as is shown with the switches of the lines 32, 33 and 35, the circuit from the contact points 8, 10 and 11 to thesolenoids is unbroken. Therefore if the thermostat contact 7 moves to engage the contact 8, the circuit is established through the solenoid 18 which should draw the core 19 to the left of the position shown as will be readily understood. In order that there may not be an excessive current consumption I have provided a notch 48 in the shaft 13 which. for instance on the closing of the circuit through the contact 8 and solenoid 18, would be drawn to the left of the position shown through movement of the solenoid member 19 and the point 47 of the switch 43 in the line (due to the fact that the member '46 is in the nature of a spring) 1n comparison .to the solenoids 1:) to 18 and are connected in parallel therewith. The solenoid 31 has a line 49 connected with the line 32, thesolenoid 30 has a line 50 connected with the line 33, the solenoid 29 has a line 51 connected with the line 34, and the solenoid 28 has a line 52 connected with the line 35. Each of these solenoids has a return line connected with the main return line '42. Normally the solenoid 27 is projected downward by the spring 25 holding the end of the latch or shaft 24' in a notch of .the shaft 13 and thus prevents accidental displacement of the shaft 13 and consequently holds the valve 4 in the set position. Upon energization of any one of the circuits 32,33, 34 and 35 the solenoid core 27 is raised releasing the shaft to movement by the practically simultanemisly energized rolenoid 15,16, 17 or 18 as the case may be. Energization of either of these last named solenoids moves the shaft 13 to certain position due to centralization of the core 19 with the energized solenoid and which positions one of thenotches 20, 21,

22 or 22-5 inalignment with the latch or shaft 24 of the core 27 and upon breaking of the circuit through the opening'bf the respective switch member 43, as heretofore stated, the core 27 is projected'downward by the spring 25 locating the shaft 13 in position.

The contact points 8 to 11 for the thermostat may be spaced a suflicient distance to require any desired change in temperature as for instance one degree of temperature change to produce the necessary movement of the thermostat to pass from one contact point to another. Considering that the contact points 8 to 11 represent a range of temperature from 69 to 72 degrees and if the temperature of the room in which the thermostat is placed is decreasing when the thermostat is set to energize the line 34 and solenoid 17, the thermostat will act and move to contact with the point 10 energizing the solenoid 16 and thereby open the fuel line to a greater extent to increase the heat of the room through the heating appliance. On the other hand if the temperature of theroom is increasing under the condition above stated, then the thermostat would tend to move to engage contact 8 and close the valve 4 and cut off the flame from the burner. 2

It is to be understood that an ordinary oil or gas burner may be used with this control device, the burner illustrated being of the fuel oil type.

From the foregoing description it is evident that a room may be maintained within a particular range of temperature by the apparatus herein shown. It is believed to be fundamentally new to use a thermostatic device to vary the intensity of the heat applied to a heating device by which the temperature of the room is to be maintained. 'lhermostats have been used to manipulate. the draft devices of the furnace whereby the rapidity of combustion of fuel as for instance coal may be varied. My invention differs in this respect, that the thermostat is here utilized in combination with various elements which directly and immediately vary the intensity of heat applied to the furnace.

Having thus fully described my invention, what I claim and desire to secure by Letters Patent of the United States is- 1. The combination with a heating ap pliance and a fuel burner through which fuel is discharged for combustion, means for controlling the intensity of the heat of combustion comprising apparatus for varying the volume of fuel discharged per unit of time, a control device for operating the same, said control device comprising a rod connected with the volume varying apparatus, electro-magnetic means for moving the rod step by step to increase or decrease the volume of flow of fuel, a series of circuits for the said electro-magnetic means through energization of each of which the rod is moved a certain distance, and a thermostat adapted by temperature change in the area heated by the appliance to successively make or break the circuits, the parts being so ar anged that a decrease in temperature of the area heated by the appliance causes the element to successively make the circuits and move the rod to increase the flow of fuel and an increase in temperature causes the thermostat to break the circuits successively and move the rod to decrease the volume of flow of fuel.

2. The combination with a fluid fuel burner for aheating appliance, of a temperature controlled device for varying the flow of fuel to the burner, said device being actuated through variation in temperature of the heated area and consisting of a valve adapted to be actuated to vary the volume of flow of fuel to the burner, an element 1nov able to operate the valve, a series of solonoids in axial alignment, a core therefor carrying the said movable element, a series of circuits for each solenoid. a contact. point for each circuit, a thermostat, a central. member movable by the thermostat from one contact point to the other to surccrsi\'cl\' complete the respective circuits, a dcrl't in temperature of the area heated causi the thermostat to increase the flow of fuel and an increase in temperature of the heated area causing the thermostat to decrease he flow of fuel.

3. The combination with a fluid fuel burner for a heating appliance, of a control device influenced through variation of tern perature of the area heated by the appliance to vary the volume of flow of fuel to the burner comprising a valve for the fuel supply,- a lever for actuating the valve, a movable element connected therewith, a series of solenoids in. axial alignment, a common core therefor for moving said element,a circuit for each of the solenoids, and a contact device adapted to close the circuits in succession in one direction or the other upon increase or decrease respectively of the temperature of the heated area.

4;. The combination with a liquid fuel burner and supply line therefor, ofa valve in the said line-adapted to be turned to vary the volume of flow of fuel through thesuprection step by step increasing the closing of the valve, and means for breaking the circuit of the energized solenoid upon movement of the core through the influence thereof.

5. A thermostatically controlled device for varying the fioW of fuel to a burner comprising the combination with the burner and supply line thereof, of a valve in the line adapted to be turned from a closed to open position or reversely, an element for actuating the valve, a series of solenoids in axial alignment, a common core therefor actuating ergized, solenoid is F l r J i i f i. v p

the movable element, a circuit for each of the solenoidsincluding a thermostatic device, aser'i'es of contacts oneifor each of the circu ts adapted to be engaged and the circuit completedthrough movement of the thermostat,'a make and break switch in each of the said circuits, energization of a sole: noid'through closing of its contact causing movement of the solenoid core and corre-' sponding movement of the valve and means whereby the switch of the circuit of the ento its position. 1 v 6. The combination with a fuel burner for a heating appliance, of a control devicein fluenced through variation of the temperature of the-area heated by the a pliance to vary the volume of flow of uel to the burner said control device consisting of a valve tor the fuel supply to-the burner, a

movable element connected therewith, a series of solenoids in axial ali nment, a common core for the solenoids a apted to move the element as the core is moved, a circuit for each of the solenoids, a thermostatically controlled device for closing the solenoid circuits in succession as it is moved in one direction or the other by increase. or decrease in temperature of the heated area and to move the movable element to inversely vary the suppl to the burner, and an electrically controlle device. forlocking the. movable element subsequent to movement by energization of a'solenoid.

In testimony whereof, I sign this specification.

DORR R. MARTIN.

broken as the core moves

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