US1703537A - Heating system and control therefor - Google Patents

Description

Feb, 26, 1929.

R. F. METCALFE HEATING SYSTEM AND CONTROL THEREFOR INVENTOR M W ATTORNEY Feb, 26, 1929. 1,703,537

R. F. METCALFE HEATING SYSTEM AND CONTROL THEREFOR Filed May 14, 1925 5 Sheets-Sheet 2 i W n wg w W /w O Y H @E y// j fw/W i il VMM Feb. 26? 1929. 1,703,537

R. F. METCALFE HEATING SYSTEM AND CONTROL THEREFOR Filed may 14, 1925 3 sheets-sheet 3 i Z1/y 116 7192 Patented F eb. 26, 1929.

UNITED STATES Parrurl'r OFFICE.

ROBERT F. METCALFE, OF BROOKLYN, NEW YORK, ASSIGNOR T SOCONY BURNER COR- PORATION, 0F BROOKLYN, NEW YORK, A CORPORATION OF DELAWARE.

HEATING SYSTEM AND CONTROL THEREFOR.

Application filed May 14, 1925. Serial No. 30,312.

This invention pertains to heating systems, controls therefor, and elements and devices therein which cooperate to give vcomplete and improved operation. It is well known that dwellings, office buildings, factories and cert-ain manufacturing agencies, such as heat treatment furnaces, steam boilers and the like, are heated by the burning of liquid fuel. lt is also well known that such heating, in most instances, is automatically controlled or governed by the amount of heat developed by the burning Vof the fuel. By

reason of the automatic operation, it becomes highly advantageous to eliminate all fire hazards and other dangers and to provide against possible failures of the operating apparatus.

` @ne of the objects of this invention is to provide an improved heating system that is fully automatic in operation and that provides safeguardsl against tire hazards, difficulties of operations and dangers which have heretofore been present in such systems.

Another object of the invention is to provide in a heating system an improved liquid fuel or oil burner of efficient operation constructed to automatically operate under normal predetermined control and to automatically cease operations when abnormal dangerous conditions exist in the boiler or fur nace, in the fuel supply, in the burner itself or at other places in the system. The control y also provides means for readily re-establishing automatic responsive operation after the burner has been stopped by reason of any abnormal condition.

A further object of the invention is to provide an improved heating system and a control therefor that have many novel features and that fully andA satisfactorily meet all the former and more recent requirements of the National Board of Fire Underwriters.

Other objects and advantages Will be more fully appreciated as a readingl of the detailed description given below is had.

There is disclosed herein an improved heat-- ing system including an efcient automatic control, and this disclosure is considered as being preferred to other systems and their -controls.

In the drawings forming part of this disclosure,

Fig. 1 is a diagrammatic view of a heating `ditions; f

Fig. 4 is a sectional view taken on the lino of Fig. 3; Fig. 5 is a sectional View taken on the line 5 5 of Fig. 3;

Fig. 6 is a sectional view taken on the line 6 6 of Fig. 7 of a fuel supply safety means;

and

Fig. 7 is a view in section taken on the line 7 7 of Fig. 6.

While the disclosure herein is specific to one heating system and its control, it is to be understood that it is susceptible to some modifications and changes that are to be considered as being within the principles of vthis invention. Further, the heating system is such that different types of boilers or furnaces and fuel burners may be employed therein if desired. For satisfactorily dis, closing the principles of this invention there 1s shown a furnace 1 of the ordinary hot water or steam type and an oil fuel burner 2 associated therewith in the usual manner. No specific constructions of a furnace and burner are herein illustrated as this heating system is considered as being adaptable for use with any satisfactory furnace and burner. However, a particular type of burner withwhich this system and its control has very satisfactorily operated is disclosed in my patent #1,491,156.

This preferred heating system includes the furnace 1, which in this instance is a steam boiler employed to heat a dwelling, ofice building, a chemical vat or the like. If desired the furnace 1 may be ay heat treatment furnace or other manufacturing facility requiring heat. In this system the burner 2 operates to burn a liquid fuel or hydrocarbon such as oil. The system provides for automatic operation and in this instance there is provided a heat responsive means such as a thermostat 3 or a pyrometer which may be positioned at any desired place to govern the amount of heat delivered. The system is provided with an automatic control which responds to the normal movements of t-he thermostat and thereby governs among other elements the normal operations of the burner 2. The controi includes safety means which protect against the operation of the system when abnormal conditions exist that would lead to dangers from tire, or explosions, or to destruction of property.

In this disclosure it is desired to specilically describe the heating system, its operating elements or devices and its control as applied to the heating of a dwelling or home.v While in such a disclosure there will be cer- Atain parts of the system that will be particularly adapted to such an application of the system, it will be understood that when the system is employed for specific industrial or other purposes certain changes, substitutions or eliminations may be made, but there has been herein shown one way in which certain regulating or controlling elements or devices may be employed and therefore the original conception is to be considered as being herein disclosed. As one example, there is herein shown a Hue control which in this instance constitutes a safety device to prevent damage in case of abnormal dangerous conditions in the furnace. When the heating system is emplolved for instance in a heat treatment furnace in an industrial organization, such a control may not be required and in that event the safety cont-rol may be eliminated or shunted from operation. Again,` certain of the safety or other operating means may not be required in industrial work, and such means may be positioned to be responsive to other conditions of the specific operation.

In this heating system the burner 2 may be driven by anv suitable means, and the control for the operation of the burner may be of any suitable form which satisfactorily responds to thc operation of the temperature responsive means or thermostat 3 and which has included therein satisfactory safety means which respond when abnormal conditions of operation of the system are present.

The burner 2 herein is of the type which supplies air to form a combustible mixture with the oil fuelV for burning; The normal operation of this particular burner is to draw t-he oil to a. nozzle by suction as by the passing of air over a definite opening in .the fuel supply line. The combustible mixture may be ignited by any suitable means such for instance as a spark-plug. This burner is pref= erably operated by an electrical motor 4 which is usually assembled on the burner base. It has been found convenient and satisfactory to control the operation ofthe biuner and this heatingsystem b v an improved electrica-l control means.

The control means includes amongotherV switch 6 mounted in the furnace and responburner to cause in this instance its intermittent burning, and the safety means herein before outlined operate to prevent normal operation of the burner in the event abnormal conditions exist in the heating system.

It is desired to provide such satisfactory safety and operating elements in this heating system as will prevent the existence of fire hazards, danger of explosion and danger when opening electrical circuits which often create relatively long sp arks between the switch points as they are separated* The safety means above noted assist in preventing operation when there is a possibility of such dangers and the circuit to the burner motor 4 is provided with `an enclosed switch 10 which eliminates dangers from sparks at the switch points.

The source of electrical power for operating the burner motor and the electrical control is f derived from power lines 11 and 12 of the ordinary house lighting circuit which is usually of 110 bolts potential. A suitable switch preferably in the form of a snap switch 14 is employed to connect the burner apparatus and its control with the power lines 11 and 12, and a suitable connection board 15 is mounted in a convenient place on the burner for carryv ing the main binding posts 16 and 17. Any desired type of motor 4 for driving the burner may be employed, but the motor preferred is one of the closed armature type provided with a. field 18 which is connected to post 16 by line 19 through enclosed switch l0, and line 20 while the other end of the field is connected to binding post 17 through line 21. When the switch 10 has been closed the motor will drive a suitable blower fan which delivers air to the burner for mixing with the oil to form the combustible mixture. In the electrical circuit for the spark-plug a line 22- leads from the line 20 to a primary transformer winding 21 and back to binding post 17 by line Q5. The spark-plug is connected through a secondary winding 26 to ground. This ignition coil or transformer llU ing 28 wound thereon and connected by linev 29 to contact point 30 which is normally' in engagement with contact 31. This contact 31 is carried by an arm 32 adapted to be oscillated b v the magnetic intensity of core 2T thus causing a spark to jump across the contacts of the spark-plug in the usual manner.

rThis may be more clearly appreciated when it is understood that coil 28 acts as a. secondary winding for coil 24 andv gives about 15 volts across contacts 30, 3l. s the flux in 5 core 2? builds up dueto the ampere turns in coil 28, arm 32 will be drawn down and contacts 30, 81 will be open thus opening the circuit through the secondary coil 28 and causing a high electro-motive torce to be instantly induced inV coil 26 and carried to the spark- .plug where. it will jump from one contact to the other and from there to ground thus operting the spark-plug. The arm 32 is electrically connected by a line 84 to a Contact 35 vwhich normally closes against a contact 36 carried by switch 9. The contact 36 is connected with the other end of the coil 2S by line 37. The preferred construction of con; tacts 35 and 36 may be noted in Fig. 4 and the details thereof' will be more fully described later. It will now ie seen from the connections above outlined that when rthc burner motor switch l0 is closed the motor 4 will rotate driving the fan for the air, and the spark-plugwill produce a spark for the ignition ot' the combustible mixture. The spark may or may not be continued during combustion.I It is preferred in this vinstance to discontinue the spa-rk While actual combustion conditions existl in the burner 2 and therefore the movement of switch 9 separa-tes the contacts 35 and 36 thereby opening the circuit which causes the operation ot' the spark-plug.

The control for this heating system may be operated in any desired manner that permits response to the thermostat 3 and to the safety means and to the presence or absence ot combustion, so that in case ot abnormal conditions in the system or the failure of ignition4 at the start of the burner or of the cessation of combustion during the runningr or by reason of the fuel supply becoming enhausted or of such nature as will give explosive mixtures` the system and particularly the burner will be stopped from further ope-rations. thereby eliminatingr danger to huma-n lite and property and to the particular apparatus in this heating system.

It. is preferred in this control to provide a suitable master control means which is changeddue to various electrical connections and to provide other mechanically operating means for operating with the master control for controlling the operation ot the burner in response to the normal operation by reason ot movements of thermostat 3 or by reason of the operation of the various safety devices. In this instance, there isprovided an electromagnetic device which forms part of the master control. This device is characterized by its capability of being substantially' magnetically balanced to prevent movement and to. be magnetically unbalanced to create movement thereof. A device of this nat-ure and a device which is preferred to be used comprises a suitable control motor 38, usually ot' nected to the ground. By reason ot' the char-` acteristlcs of motors of this character, when there is a circuit closed between brushes 42 and 44, there will be rotation ot the motor. Thus the motor will be considered as being` magnetically unbalanced. lVhen there is a circuit closed only between brushes 42 and 4?, there will also be rotation of the motor. and thus-the motor Will be considered as being magnetically unbalanced. It. however. there is a circuit through brushes 42 and 44 and a circuit through brushes 42 and 45, the motor then becomes substantially magneticallliv balanced and its rotation ceases. The stopping ot the motor when the two circuits are closed is due to the fact that each of the single circuits endeavors to cause the motor to rotate in opposite direction.

lWith this repulsion control motor, it is noted that the circuits which extend from the brushes are of a voltage considerably less than the 11() volts impressed across supply lines 11 and 12. Thus the control part ot the heating system will be operated on alow voltage. The low voltage usually approximates 10 volts.

The control motor 38 is adapted to: drive mechanically a distributor 46. and there is herein shown diagrammatically a suitable shat't 47 for the drive. It will be understood that any desired gearing may be employed between the motor and the distributorrso that the proper speed ot rotation of a distributor arm 48 will be possible. Mounted on this shaft 47 is a suitable cam 49 which operates ony a rocker arm 50 against extension 51, thereby causing its other extension 52 which carries the burner motor switch 10 to move. to open or close the contacts in the switch 10. It. is usual in this enclosed type ot' switch to have a. quantity of mercury which moves to close the circuit between the two switch points.

The distributor mayv e of any desired construction or formation so long as it provides a suitable number of contact segments which are adapted to be wiped by a contact arm moved by the control motor. In this construction, it is preferred to have the Contact segments of annular construction and to have them mounted concentrically, so that the arm 48 pivoted on shaft 47 may Wipe over the segments during its movementI by the rotation of the control motor. In such a construction, there is herein provided segment 54 which is in length about 320 degrees of a circle. Mounted ,concentrically with segnient 54 is segment 55, which is about 300 degrees of a circle in length. It is desirable to have the segment 54 longer than the segment 55, so that, under normal operating conditions of this heating system, the arm 48 will engage only the segment 54 when the burner 2 is normally stopped. This position of larm 48 is considered to be the starting position of the operation ot' this heating system. It is to be understood that while t-here is approximately 2O degrees difference in length between the two segments, this dinerence may vary consideiably or there may be. some means of raising a contact 56 carried by the arin 48 from the segment 55 while at. the same time allowing a contact 57 carried by the arm to engage segment 54. The main purpose is that, in normal stop condition of the burner, the contact 57 will be in engagement with segment 54 and the contact 56 shall be out of engagement withsegment 55.

This distributor also piovides for a segment 58 which may be suitably positioned to receive the distributor arm 48. In this instance, segment 58 is shown as being positioned between the ends of segment 54, so

that contact 57 will engage segment 58 under certainfconditions of operation, later to be described in full. This segment is positioned so that contact 57 would engage therewith. It is, however, quite immaterial as to which of the contacts carried by the arin- 48 engages segment 58 so long as an electrical circuit may be' established to cause the control iiiotor to rotate. This segment 58 usually is termed a safety stop segment, and when the distributor arm 48 engages the same, it is considered that the arm is in a safety stop position. YVhen the arm 48 so engages segment 58. the burner has been stopped by reason of the existencev of some abnormal condition in the heating system. Under such circumstances. it is desirable to be able readily to return the control system back to its normal responsive position. It is herein provided that some additional operation shall be completed in order to accomplish this end. This additional operation may be performed manually or may be accomplished by some automatic or remote control. However', for the purpose herein disclosed. there is provided a suitable push buttoii.59 which closes a circuit through the motor 38 and the distributor. causing the motor to rotate, moving the arm 48 to its normal position in engage-4 nient with segment 54 alone.

ments 54,55 and 58, and the distributor aim 48 and the main normal control in the form of the thermostat 3.

In the complete heating system, the furnace employed, as hereinbefore noted, may be a boiler. hot air or other desirable type of furnace. In the event excessive heat is developed, the furnace itself will absorb only a certain amount, and thereafter developed heat will mostly pass through the flue to the atmosphere. In furnaces which are of the hot water or steam type, the heat developed will normally be absorbed by the water, and should this water become exhausted the heat will then bring the furnace to its heat saturation point vand the heat thereafter developed will pass to and through the flue. It is well understood in the heating art that the boiler sections crack and are ruined by reason of low water conditions and thus cause excessive repair expense. The heating system herein disclosed prevents operation of the apparatus when the furnace or boiler has abnormal conditions existing therein. Normally, a boiler will absorb the heat, and the hot water or steam will be conducted away from the boiler.

Should anything happen to prevent such conduction of the heat, then excessive steam is developed, and in that instance the safety means 6 operates to open a circuit to the con- `.trol motor and stop the burner, or prevent the starting of the burner.

It' the heatdeveloped becomes excessive in the flue, the safety means 7, which may be of any suitable form, will operate to open the circuit. In this instance, the fusible link employed will melt and open the electrical supply line. In order to provide some means for indicating whether this fusible link is melted or not. there is provided an indicating or pilot lamp 60 connected across the lines l1 and 12. In oider to test whether link 7 is melted. snap switch 14 is turned on and by reason of current being draw due to the fact` that field 39 of the control motor is closed, the pilot lamp will light to indicate that the fuse has not been melted. If the indicating lamp 60 remains dark. then a new link will be Arequired to be placed in the liuc. While there is herein described a specific type of ilue control iii'eans, itis to be understood that other satisfactory means for accomplishing the same result may be employed. It is to be noted that when the flue control safety means has operated or been melted, the electrical supplies to the burner motor and to the electrical control will both be opened so that further operations of the burner itself or control therefor will be prevented.

It is desirable to provide the furnace safety means G in such form as. to be responsive to steam pressures, for when this heating system, as heretofore noted, is installed in dwellings and the thermostat 8 located in one of the rooms, it will be seen that in the morning high steam pressures would be developed in the furnace before thermostat 3 would become responsive to stop the burner. When the steam in the furnace reaches a predeterniined pressure, the safety means 6 operates to open a circuit to the control motor, thereby causing the burner to cease operations.

This heating system includes a suitable safety means responsive to abnormal conditions of the feeding of the fuel to prevent operation of the burning apparatus when there are dangers of fires and explosions. Any particular safety means may be employed for this purpose. It is found, however, that in the oil burning type of heating system, it is desirable to provide a safety means which operates when the level of the oil varies a predetermined amount from its normal. In the present system there is provided electrically connected in series with the thermostat 3 a contact 6l positioned to engage contact 62 to maintain the circuit closed under normal conditions of fuel feed. A float 64 is provided with a stem 65 which engages an arm 66. Stops 67 and 68 are placed on the stem 65 and permit predetermined movements of the float 64 without moving the arm 66. In the event the level of the fuel drops below a predetermined point, stop 67 engages arm 66 and the down- Ward pull on the right-hand end of arm 66 opens contacts 6l and 62, thereby opening the control circuit and preventing operation ofthe burner; or, if the burner is in operating condition, to cause the same to be stopped. In the event the fuel level is too high, stop 68 engages arm 66, and the upward push on arm 66 raises the same, thereby separating contacts 6l and 62, creating the same safety operations as under the conditions of low level.

One of the main purposes of this safety means 5 is to prevent the operation of the burner when the. fuel level is so low as to preclude the supplying` of a. sufiicientquantity ot' oil. for it is recognized that when a too small quantity of oil is mixed with predetermined quantities of air, an explosive mixture results. This particular safety means prevents operation of the burner under such conditions. Willen the oil level is too high, which would` permit the oil to leak from its chamber to the basement floor, it would be dangerous to start the fuel burner, and thus the safety means 5 prevents the operation of the burner under such conditions, or, if the burner is running. stops it, thereby eliminating fire hazards. While this type of safety means 5 is shown in diagrammatic form inv Fig. l, the preferred mechanical construction thereof is illustrated in Figs. 6 and 7, and will be more fully described hereinafter.

It has been stated that the thermostat 3 operates to lgovern the main control under normal conditions of operation of the heating system. Various types of thermostat may be employed 4for this purpose. @ne of the main diiiiculties with thermostats is the flutteringwhich takes place and thus prevents the completion of operation. In this disclosure there is; provided a main moving Contact member 69 of the thermostat which carries a magnetically influenced element 70 and an electrical contact 7l. Positioned near the movable member 69 is a core 72, which is magnetized by coil 74v provided in line 75. The other end of the coil is connected to contact point 76. In the operation of this thermostat, the movable member 69 moves t0 the left by reason of its expansion characteristics, permitting contact-s 7l and 76 to engage, thereby closing the circuitand creating magnetic force in member 72 which, acting on .element 70, pulls the member 69 over and maintains it in that condition, resulting in firm engagement of contacts 71 and 7 6.J This condition will continue until the thermostat operates by reason of heat developed to open the contacts. The thermostat herein shown is to be considered as a two-point thermostat.

rfhe operation of this heating system and the burning apparatus included therein is as follows under normal conditions when it'is assumed that the fuel feed safety means 5 and the boiler safety means 6 are in normal closed condition. The distributor arm 48 is assumed to be in its normal position in contact with only segment 54. By reason of lack of heat, the thermostat member 69 will move to close contacts 7l and 76, thereby closing an electricalk control circuit as follows: from ground to distributor arm 48, to segment 54, to thermostat'member 69 by line 77, through coil 74 and line 75, switch contacts 6l and 62, line 78 through relay 79, line 80 through safety means 6, line 81 to brush 44, .through the armature of control motor 38 and brush 42 to ground. This gives one circuit through the control motor and will cause rotation thereof. In the movement of the motor, shaft 47 will bc rotated, causing switch 10 to be closed by reason of the movement of rocker arm 5t), and the distributor arm 48 will be mechanically driven so that it wipes across segments 54 and As heretofore noted, the spark-plug will be placed in operation as soon as switch l() closes. Contacts 35 and 36 in the spark-plug circuit will be closed due to the fact that there is no combustion taking place in the burner. The control motor 38 normally continues to rotate until combustion takes place unless there is no fuel when it will stop for arm 48 has reached safety stop segment 58. The distributor arm has a permissible travel from the time it simultaneously engages segments 54 and 55 until it should pass onto segment 58. The lengths of segments 54 and 55 are such that combustion Will take place before distributor arm reaches the point where it passes from segments 54 and 55, unless there is some unusual diliiculty. It

will be seen that the distributor arm may stop at any point along its permissible travel due to combustion taking place. Instantly upon the lighting of the combustible mixture or the initiation of combustion, 'the Vpressure derived therefrom causes switch 9 to be moved, overcoming the resistance of an adv is then no closed circuit from segment 55 to brush 45 of th'e control motor, and the motor will operate and continue to operate due to the closed circuit across brushes 42 and 44. The relay 79 acts to separate contacts 87 and 88 before the distributor arm engages segment 55. l

With the closing of contacts 84 and 851due to combustion taking place, a second circuit to the control motor is completed as follows: from ground to contacts and 84, through the tlapper switch, line 89, line to brush 45 on control 'motor 88, thus there is established a second circuit through the control motor; and by reason of the position of brush 45 in respect to brushes 44 and 42, and by reason of the windings of the field and armature of this control motor, itis required to stop rotation, as the circuitthrough brushes 42 and 44 endeavors to rotate the armature in onegdirection and the circuit through the brushes 42 and 45- endeavors to cause the armature to rotate in the opposite direction. When both of these circuits are closed, there is a substantial magnetically balanced condition existing in the motor, and it ceases to rotate. The burner now operating to burn the combustible mixture, and it will so continue under normal conditions of operation until the thermostat 3 opens, thereby separating contacts 71 and 76 and opening the circuit across brushes 42 and 44.9 The opening of this first circuit leaves the second circuit through brushes 42 and 45 predominant, and the control motor is caused to rotate in tire opposite direction, moving the distributor arm 48 incounter clockwise direction back to its normal position inV engagement with only segment 54 and in position to start up again. The opening of the first circuit causes relay 79 to release arm 86, there- Pby permittingI contacts 87 and 88 to engage, thus creating a semi-substitute circuit for the second circuit, which causes the counter clockwise movement of arm 48 back to normal condition, for the first circuit through segment 54 has been opened, and dueto cessation of combustion, switch 9 is moved by weight 82 back to normal hang position.

In the event of failure of ignition in the I burner at the beginning, the flapper switch 9 would not be moved, as there would be no pressures resulting from combustion. Therefore, the first circuit across brushes 42 and 44 of the control motor would continue and cause the motor to continue rotation, moving the distributor arm 48Y onto safety stop segment 58 where all circuits to the control motor would be opened. At the same time, the motor switch l() to the burner motor would be opened and consequently all operations of the burner apparatus would be stopped. By pressing the push button 59, a circuit is created from ground, control motor brush 42, armature of control motor 88, brush 44, line 94, push button 59, line 95, segment 58, and distributorarm 48 to ground, thereby causing` the control motor to rotate, moving the distributor arm onto segment 54, thus placing the apparatus back into normal responsive condition; that is, responsive to the operation of the thermostat.

yIn the event ignition takes place at the beginning and there is later a failure of combustion for any reason, the dapper switch by reason of the Weight 82 would move to its normal hang7 position separating the contacts 84 and 85, leaving the first circuit closed through brushes 42 and 44, and the control motor 38 would thereby rotate as the second circuit would be open, 'and distributor arm 48 would be moved onto safety stop segment 58 or into safety stop position, stopping the operations of the apparatus as before described. It will be noticed that the lapper switch is instantly responsive tot-he pressures of combustion. It will be seen that, since the iiapper switch isA responsive to combustion conditions, in the event there is a cessation of combustion there is instantly a change in the control `system which immediately leads to the stopping of the burning appai'atus.

'Referring now to the other safety means, it will be noted that it is preferred to have the thermostat 3, the fuel feed safety means 5 and the boiler safety means 6 all connected iii series in the first circuit through the brushes 42 and 44 of the control motor, and thatthe second circuit includes the flappei' switch which is responsive to the conditions of combustion and that the closing of both ofthe circuits causes the motor to stop rotation. It will also be noted that if both of these circuits are open the motor will not rotate. Further, it will be noted that when the motor is stopped by reason of the closure of both circuits that there may be a selectiveA unbalancing of the motor, that is, the .inbalancing will cause the motor to rotate clockwise or counter clockwise. The unbalancing may result from abnormal conditions of combustion, fuel feed or furnace conditions. The unbalancing will also result from the opening of the thermostat. lin addition, the safety device in the flue may operate to stop all operation of the heating system. Each of the various safety means is responsive separately and acts separately to stopl the apparatus. It is recognized, however, that the safety means act through the control motor 38. But each particular safety means is independent of any other safety means and it functions to automatically and independently stop the operations of the burning apparatus. 1t is also to be noted that the operation of any of the safety means changes the electrical connections in the control.

Referring now to Figs. 3, 4 and 5 a particular type of tiapper switch is herein disclosed. A part of the frame 95 of the burner 2 is provided with an opening 96 in which there is placed a suitable plate 97 usually pivoted at 98. This plate 97 is so constructed that it substantially and practically fills the opening 96. The plate carries thecoptact 35 of the spark-plug circuit. A ring 99 is aiiixed to the part 95 and pivotally carries a frame 100 which is provided with a projection 101 carrying a roller 102 which in turn normally engages the plate 97. When combustion takes place the pressures developed by combustion cause the plate*97 to be pivoted about its pivot point 98 to press against the roller 102 causing frame 100 to oscillate to the left. This frame 100 `carries the weight 82 which is adjustable on the screw threaded rod 104 so that the response to the movement of plate 97 may be varied if desired. The ring 99 carries an arm 105 of electrically conducting material which is adapted tobe engaged by contact 84 carried by the frame 100. The extreme free end of the electrical conducting arm 105 forms contact 85. It will be seen that when combustion takes place, contacts 84 and 85 will. be closed and create the closing of the second circuit as above defined.v The frame 100 is adapted to carry contact 36 at its lower end. wWhile contacts 35 and 36 are illustrated -as being mounted in definite positions they may be mounted in any particular desired manner. There is, however, a certain advantage in their present locations in that when the frame 100 and the plate 97 oscillate back to their normal positions contacts 35 and 36 will/ be brought together with a definite pressure as both frame 100 and plate 97 oscillate about definite pivot points. Suitable electrical flexible conductors are Shown as being connected to the various contacts with this type of flapper switch construetion. These conductors may be varied as desired respecting their forms and locations. The preferred construction of this switch as herein illustrated functions to be instantaneously responsive to the beginning of combustion and to`thek cessation of combustion.

Referring now to Figs. 6 and 7 the preferred feed fuel safety means will be described in detail.` This means is diagrammatically shown on the burner 2 in Fig. 1 and the frame 106 thereof constitutes a chamber for receiving fuel in the form of oil to a norm mal level .illustrated by the line 107. The fuel preferably enters the safety means by pipe 108, passes through valve passage 109 to the chamber formed in frame 106 and passes therefrom' through pipe line 110. A suitable fioat 111 and the usual operating means responsive to the position of the float 111 vary the setting of valve rod 112 at its seat ofthe valve passage 109. The float 04 is shown to the left of float 111` and is adapted to movein accordance with the position of the level of the fuel. This float 6st carries shaft 11st which is guided by its lower end by a suitable frame 115 and at its top end it carries a plate 116. This plate is provided with a slot 117 and with arms 118 and 119 which are respectively adapted to engage stops 68 and 67. The switch 5 is provided with contacts 61 and 62 and mercury in reservior 120 operates to close and open switch 5. T he mercury reservoir comprises an elongated tube 120 having a recessed portion 120 in one end thereof, as shown more clearly in Fig. 6. Mercury contacts 61 and 62 extend Awithin the tube 120 and are so positioned that when the tube is tilted to the left, as shown in F ig. 6, mercury covers both of the con; tacts 61 and 62, forming a closed electric circuit. Current then flows through conductors 78 and 78 to contact terminal 61, from terminal 61 through the mercury to-contact termi- 'nal 62,.from terminal 62 through conductors and 75, completing the electrical circuit through the remaining conductors and devices heretofore described. When the mercury tube tilts to the right, the mercury flows away from contact terminal 61, breaking the electric circuit. This opening and closing is completed Within the completely closed wall of the switch thereby eliminating fire hazards.

It will be noted that when the level of the fuel rises that projection 1-18 engages stop 68 and moves the switch 5 to its open position. Vhen the, level of the fuel lowers, float 64 will drop causing extension 119 to engage stop 67 thereby moving the switch 5 to its open position. The construction of this particular type of safety means is simple'and permits satisfactory normal operation but prevents the operations of the burner when abnormal fuel feed conditions exist. A satisfactory means for cleaning the fuel fee-d chamber is provided by suitable plugs 121 and 122. i

From the foregoing complete description it will be noted that there is herein disclosed an improved heating system having its burning apparatus operative in a very efficient manner under normal conditions, and that when abnormal conditions exist in the system suitable safety means are provided for inratus; and an automatic electrical controlling stantaenously perfecting changes Whichstop means for governing said feeding, igniting the opera-tions of the burner. Suitable modiand operating; said control means having fications and changes may be made in the included therein a control motor which has heating system and its control and its devices more than two brushes on its commutator and and its operating elements as desired, but it each brush being electrically connected to is to be understood that such changes and part of said electrical control means to form modifications are considered to be Within the predetermined electrical circuits under varyscope and principles of this invention as outing conditions of operation to normally give lined in the following claims. automatic operation of said burning apparalVliat I claim is tus and to stop said apparatus when abnor- 1. In an oil burning apparatus, the combimal conditions of fuel feed and burning exist, nation of means for feeding, igniting and said motor having its field excited under all burning oil fuel; a master control for governconditions of operation of said apparatus. ing said feeding, igniting and burning; said 5. In an oil burning apparatus, the combimaster control including a rotating control nation of means for feeding and igniting the motor `capable of being placed in magnetic oil fuel, and means for operating said appabalance to stop movement thereof and of beratus; and an automatic electrical cont-rolling ing magnetically unbalanced When energized means for governing said feeding, igniting to cause movement thereof; a temperature4 and operating; said control means having inresponsive device for normally varying'said deluded therein a control motor which has control; and safety means for magnetically more than two brushes on its cominutator and unbalancing said magnetic means when abeach brush being electrically connected to normal conditions of operation exist to therepart of said electrical control means to form by stop normal operations of said apparatus. predetermined electrical circuits under vary- 2. In an oil burning apparatus, the combiing conditions of operation to, normally give nation of means for feeding, igniting and automaticy operation of said burning appaburning oil fuel; a master-control for norratus, said motor having its field excited mally governing said feeding, igniting and under all conditions of operation of said apburning; said master control including paratus, and instantaneously acting safety means capable of being placed in magnetic means connected in said automatic control balance to stop movement thereof and of beand being responsive to conditions of com-` ing magnetically unbalanced to cause movebustion in said burner to vary the electrical ment thereof; a temperature responsive decontrol means to stop said apparatus. vice for normally varyingv said master con- 6. In an oil burning apparatus, the comtrol; safety means for magnetically unbalbination of means for operating said apparaancing said magnetic means when abnormal tus, said means including the feeding of the conditions of operation exist to thereby stop fuel, and an automatic electrical control sysnormal operations of said apparatus; and a tem for governing the operation of said apsafety stop electrical contact to which a part paratus, said control system including a conof said control moves after operation of said trol motor having three brushes each of safety means. which is electrically connected in said control 3. In an oil burning apparatus, the combisystem, an electrical distributor having t'o nation of means for feeding, igniting and electrical conducting segments connected in burning oil fuel; a master control for consaid control system, and a. movable arm trolling said feeding, igniting and burning; adapted to span said segments under predesaid master control including an electromagtermined operating conditions to vary the netic device being substantially magnetically electrical control system, said movable arm balanced to prevent movement thereof and of being moved in response to movements of being magnetically unbalanced to create said control motor. movement thereof; safety means responsive 7. In an oil burning apparatus, the comto abnormal conditions of fuel feeding and binat-ion of means for operating said burning burning to causey said electromagnetic device apparatus, said means including the feeding t-o be unbalancedto thereby cause said appaand igniting of the fuel, and an automatic ratus to stop operations; a safety stop electrielectrical control system for governing the cal contact to which an electrical conducting Operation 0f Said apparatus, vsaid control sysmember of said control is moved after operatem including a three-brush control motor, a tion of Said Safety means; and a separate/ly distributing switching means electrically operative device in said control adapted to connected in said control means for varying vary said control to move said part from said the electrical connections in said control safety stop contact to thereby replace the conmeans under predetermined conditions and trolgfor normal opera-tion.' being driven by said control motor, a switch 4. `In an oil burning apparatus, the combiinsaid control system operated by pressures nation of means `for feeding and igniting the developed by the existence of combustion in oil fuel, and means for operating said appasaid apparatus for varying the electrical control system to allow normal operation of said burning apparatus, and means in the control system for controlling the ignition, said ignition means being associated with said switch and adapted to be rendered inoperative when said switch is moved in response to the existence of combustion in said apparatus.

8. In an oil burning-apparatus, the combination of means for operating said apparatus, said means including the feeding and the igniting of the fuel, and an automatic electrical control system for governing the operation of said apparatus, said control sys-4 tem including a control motor having three brushes each of which is connected in said control system, an electrical distributor having two electrical conducting segments connected in said control system, a movable arm adapted to span said segments under predetermined operating conditions to vary said electrical control system, said movable arm being moved in response to niovemeuts of said control motor, said inotor having. its field excited under all conditions of operation of said apparatus, a switch operated by pressures developed by the existence of combustion in said apparatus, and being connected in said automatic control means to change the same upon being operated to allow continued operation of said burning apparatus, the ignition means being electrically associated with said switch and adapted to be rendered inoperative when said switch is moved in response to pressures developed by combustion.

9. In an oil burner apparatus, the combination of a burner, means for feeding fuel thereto, means for igniting the fuel, an electrical control system for governing the operation of said burner, a control motor connected in said control system, said control motor having two opposed windings adapted when energized separately to causev said control motor to rotate in opposite directions and when both are energized simultaneously to prevent the motor from irotating in either direction, means for energizing one of said windings to start said burner in operation, means for energizing the second winding after said oil has been ignited to prevent further rotation of said control motor and thereby allow normal burning operation of said apparatus to continue, said second winding adapted to return the operating parts of said apparatus to their normal positions after said first winding has been deenergized, said rst winding adapted to continue the rotation of said control motor to a predetermined stop when said second winding is not energized thereby stopping the apparatus. 10. In an oil burner apparatus, the combination of a burner, means for feeding oil thereto, means for igniting the oil, an electrical control system for governing the operation of said burner, a three brush motor connected in said control system, a winding in said motor connected between two brushes for causing clockwise rotation thereof, a second winding in said motor connected between the third brush and one of the other brushes for causing said motor to rotate counter-clockwise, means in said control sysi tem for energizing one of said windings to start operations of said burner, and a second means also connected in said control system and operable upon accomplishing a predetermined burner condition for energizing said second winding while said iirst winding is energized to thereby cause said contro] motor to be substantially magnetically balanced and thus stop rotation thereof, said burner apparatus continuing normal operations while said control motor is thus balanced.

l1. In an oil burner apparatus, the combination of a burner, means for feeding fuel thereto, means for igniting the same, an electrical control system for governing the operation of said burner, a three brush repulsion motor connected in said control system, a heat responsive means adapted to close the circuit between tivo of said brushes of said control motor when heat is required to thereby start the operation of said burner apparatus, a movable member associated with said burner and movable under pressures developed by combustion in said burner, and an electrical contact carried by said member and adapted when fuel is burning in said burner to close a circuit in said control system between the third brush and one of the other brushes thereby stopping the rotation of said control motor as the two circuits in said motor oppose each other, said burner continuing normal operations until one of said circuits is opened.

12. In an oil burner apparatus, the combination of a burner, means for feeding oil thereto, means for igniting the oil, an electrical control system for governing the operation of said burner, a three brush control motor connected in said control system, said control motor having a winding between two brushes which when energized causes said motor to rotate clockwise, a second winding between the third brush and one of the other brushes woundiii opposition to said first winding for causing said motor to rotate counter clockwise when energized, means for energizing the first winding to start the burner apparatus, means for also energizing the second winding when the fuel has been ignited, said two opposed windings thus energized causing said motor to stop its rotation, said second winding acting to return said controlsystem to its normal non-operative position when said first winding has been deenergized, and means for maintaining said second winding energized until said .control system has returned to its normal position.

13. In anoil burning apparatus, the combination of a burner, means for feeding fuel." thereto, means for operatlng sald burner,

electrical control means for governing the operation of said burner operating means, a control motor included in said control means, a distributor having two substantially annular electrical conducting segments connected to said control means, a distributor arm mounted to Wipe over said segments in response to movements of said control motor to vary the electrical connections in said control means to allow continued operation of the burning apparatus under normal conditions and to stop the apparatus under abnormal conditions, and means responsive to pressure developed by combustion of lsaid fuel in said burner to instantly stop the operation of said control motor and to, thereby stop the movement of said'arm over said segments thereby maintaining closed an electrical circuit which allows the burning apparatus to continue normally.

14. In an oil burning apparatus, the c0111- bination of a burner, means for feeding fuel thereto, means for operating said burner, an electrical control means for governing the operation of said burner operating means, a control motor included in said control means, a distributor having two substantially annular electrical conducting segments mounted concentric to each other and connected in said cont-rol means, one of said segments being of greater length than the other, a distributor arm mounted to engage the longer segment in normal stop position and to Wipe over and Contact with said segments in response to mov'ments of said control motor to vary the electrical connections in said control means, and electrical means connected to said control motor and being operated by pressures developed by combustion of said fuel in said burner for changing the electrical balance of said control motor to cause the same to start or stop. y y

15. In an oil burning apparatus, the combination of a burner, means for feeding fuel thereto, means for operating said burner, an electrical control means for governing the operation of said burner operating means, a control motor connected in said control means, a distributor having two substantially annular electrical conducting segments, a distributor arm lnounted to normally engage only one of said segments in normal stop position and to wipe over said segments in response to movements of said control motor to vary the circuits in said control means, means responsive to pressures developed by combustion of said fuel in said burner to govern the operationl of said control motor to immediately stop the movement of said arm over said segments, and a temperature responsive means for governing the normal operation of said burning apparatus to cause the control motor to move said arm until combustion pressures operate to stop said motor and upon the next movement of said te1nperature responsive means to returnsaid arm to normal position.

16. In an oil burning apparatus, the combination of a burner, means for feeding fue] thereto, means for operating said burner, an electrical control means for governing the operation of said operating means, a control motor connected in said electrical control, a distributor having two electrical conductingr segments positioned beside each other and connected in said control means, one of said segments being longer than the other, a distributor arm mounted to Wipe over said segments simultaneously in response to movements of said control motor, said arm being normally positioned in engagement with only one of said segments in normal stop position and adapted to engage both of said segments when set in motion by said control motor, and means responsive to pressures developed by combustion of fuel in said burner to vary the operation of said control motor to instantaneously stop the movement of said arm over said segments and to move said arm back to its normal position in contact with said longer segments after normal combustion has A ceased.

17. In an oil burning apparatus, the combination of a burner, means for operating the same, an electrical control for governing said operating means, said control having a con@ trol motor included therein, a distributor connected in said electrical control and having two substantially annular segments mounted concentrically, one of said segments being longer than the other, a distributor arm for normally engaging only the longer segment when in normal stop position and adapted in its movement to Wipe over said segments simultaneously, said arm being driven by said motor, a safety stop segment positioned to be engaged by sald arm, a safety means instantly vresponsive to burner conditions and operating to vary the movements of said control motor and said arm to move said arm to said safety stop segment upon failure of ignition and when there is failure ofcombustion.

18. In an oil burning apparatus, the combination of a burner, means for operating the same, an electrical control for governing said operating means, said control having a control motor included therein, a distributor connected in said electrical control havin" two substantially,annular segments mounted concentricallygone oil-,said segments being longer than the other, a distributor arm cngaging only the longer segment when said burner is not operating and adapted during its movement after starting of the burner to Wipe over said segments simultaneously, said arm being driven by said motor, a safety stop segment positioned to be engaged by said arm under predetermined conditions, a safety llO means responsive. to burner conditions and operating to vary the movements of said control motor to move said arm to said safety stop segment upon initial failure of ignition and when there has been a failure of combustion, and separate operating means for operating said electrical control for causing said arm to be moved from said Safety stop segment to normal stop position.

19. In an oil burning apparatus, aburner, means for feeding fuel thereto, a motor for operating said burner, a source of electrical supply for said motor, an enclosed switch for controlling the electrical supply to said burner motor, electrical control means for governing the operation of said burner motor, a three brush motor connected in said control. means, a distributor mechanism also connected in said control means for varying the electrical circuits thereinp said distributor being mechanically connected with said three brush motor and driven thereby, means as-` sociated with said mechanical connection for opening andclosing said enclosed switch in the burner motor circuit, and a. safety stop segment in said distributor mechanism to which a part of said mechanism is moved in response to abnormal burning conditions in said burner causing said burner motor switch to open and said three brush motor to stop.

20. In an oil burning apparatus, the combination of a burner, means for feeding oil to said burner, a motor for operating said burner, an electrical control for governing the operation of said burner motor, a three brush motor connected in said electrical control, a switching means mechanicallyT driven by said three brush motor, an enclosed switch for opening and closing an electrical supply to said burner motor, mechanical means associated with and operated by said three brush motor for operating said enclosed switch, a temperature responsive means for mainly controlling the operation of said three brush motor to thereby control the operations of said burner, a safety stop segment in said switching means to'which one part of said.

switching means is moved when there is initial failure of ignition and when there is cessation of combustion in said burner, a switch operated by pressure resulting from the burning of said oil fuel, said switch adapted to close a circuit through said three brush motor to cause said motor and said switching means to stop, and a safety `means electrically connected to said three brush motor and being responsive to abnormal levels of said fuel for preventing the operation of said burner.

21. In an oil burning apparatus, the combination of a burner, means for feeding fuel thereto, means for operating said burner, electrical means for controlling said operating means, a control motor connected in said electrical control and adapted to be magnetically balanced to stop the rotation thereof under predetermined conditions, a switching mechanism, connected in said electrical control and adapted to be driven by said control motor, a movable arm included in said switching mechanism, a safety stop contact to which said arm is moved when abnormal conditions of operation exist in said burner, and means connected in said electrical control for selectively unbalancing magnetically said control motor to cause said arm to be moved to its normal position or to said safety stop Contact.

22. In an oil burning apparatus, the combination of a` burner, means for feeding fuel thereto,` means for operating said burner, electrical means for controlling said operating means, a control motor connected in said electrical control and adapted to be magnetically balanced to stop the rotation thereof under predetermined conditions, a switching mechanism connected in said electrical control and adapted to be driven by said motor, a movable arm included in said mechanism, a safety stop contact adapted to be engaged by said arm under predetermined conditions, a temperature responsive means connected in said control and to said control motor, and a combustion responsive device connected in said control' and to said control motor, said control motor adapted to be started by the closing of said temperature responsive device and to be stopped by operation of said combustion responsive device and to thereafter be rotated in one direction by the opening of said temperature responsive device and in the other direction by the opening of said combustion responsive device which causes said arm to be moved to said safety stop contact.

23. In an oil burning apparatus, a burner, means for feeding fuel thereto, means for operating said burner, electrical control means for governing said operating means, an electrical distributor connected in said electrical control means, said distributor comprising an angular segment of approximately 320 degrees of a circle in length, a second segment of approximately 300 degrees of a circle in length and mounted concentric to said first segment, a safety stop-electrical conducting segment positioned between the ends of saidA first segment and insulated therefrom, a distributor arm normally positioned to engage said first segment in normal stop position, and means for moving said arm to wipe over said first and second segments in a clockwise direction under certain conditions of burner operation and to move in a counter clockwise direction under other conditions of burner operation and to be moved onto said safety stop segment when said fuel does not ignite after said burner has been started.

This specication signed this 13th day of May, 1925.

' Y ROBERT F. METCALFE.

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