US2197175A - Combustion control system - Google Patents

Description

April 16, 1940- L. CUNNINGHAM 7 COMBUSTION CONTROL SYSTEM Filed Sept. 5, 1935 .zhvemtor.

le wtlsllfiunnin gham,

Patented Apr. 16, 1949 UNITED STATES PATENT OFFICE COMBUSTION CONTROL SYSTEM Application September 5, 1935, Serial No. 39,253

4 Claims.

This invention relates to a combustion control system.

It is an object of this invention to provide a combustion control system wherein the draft 5 through a boiler or furnace is varied in accordance with the fire temperature or furnace temperature.

Another object of this invention is to provide a combustion control system using a draft damper for regulating the draft through a furnace or a boiler wherein thermostatic means responsive to fire or furnace temperatures positions the draft damper so that a given draft may be provided for a given fire condition.

l6 A further object of this invention is to provide a combustion control system of the type described above wherein means are provided for adjusting the controlling effect of the temperature responsive means whereby the draft damper :0 may be adjustd to various positions for a given fire or furnace temperature.

Still another object of this invention is to provide a combustion control system of the class described above wherein means are provided for preventing automatic operation of the draft damper and for placing the draft damper under manual control.

Another object of this invention is to provide a combustion control system for a boiler having 0 fuel supply means and draft regulating means wherein the fuel supply means and the draft regulating means are both controlled in accordance with fire temperature. I

Still another object of this invention is to pro- 5 vide a combustion control system having safety devices and signal devices hooked up with a fuel feeding mechanism whereby safe operation of the fuel feeding mechanism is provided.

Other objects and advantages will become ap- 0 parent to those skilled in the art upon reference to the accompanying specification, claims and drawing in which drawing there is diagrammatically illustrated the combustion control system of my invention.

My combustion control system, for purposes of illustration, is shown as being applied to a boiler generally designated at III. Boiler I Ii is shown as being provided with a fuel supply nozzle II of the powdered fuel type receiving powdered fuel through a pipe or conduit I2 from a pulverizer I3. The fuel is placed in a hopper I4 and is fed to the pulverizer I3 in a manner known in the art, and the pulverized fuel is then fed from the pulverizer I3 into the boiler II through the pipe I2. The pulverizer I3 may be operatedby an electric motor designated at I5.

Boiler I0 is shown as being provided with a stack I6 and located in this stack I6 is a draft regulating means which may take the form of 5 a draft damper I'I. By positioning the draft damper I1 between its full open and its full closed positions, the draft through the boiler I0 may be accurately regulated. The draft damper I1 is operated by a lever I8 which is connected 10 to a .rack bar I9. The rack bar I9 is operated by a pinion 20 mounted on a shaft 2|.

The shaft 2I may be operated by a proportioning motor of the type illustrated in my Pat ent No. 1,989,972 patented on February 5, 1935. For purposes of illustration in this application, I have shown the motor for operating the damper I! to comprise a gear 22 mounted on the shaft 2| and driven through a reduction gear train 23 by motor rotors 24 and 25. The motor rotors 24 and 25 are operated respectively by field windings 26 and 21 and upon energization of the field winding 21 the draft damper I1 is moved towards a closed position, and upon energization of the field winding 26 the draft damper I1 is 25v moved towards an open position. Also mounted on the shaft 2I is a worm gear 28 in operative engagement with a sector plate 29 pivoted at 30. The sector plate 29 carries contacts 3| and 32. Also carried by the sector plate 29 is a switch arm 3 33 adapted to engage either contact 3| or 32. The sector plate 29 also carries pins 34 and 35 which are adapted to engage with limit switches 36 and 31 respectively when the sector plate 29 is moved to either extreme position.

The switch arm 33 is operated through spring 38 by a core or armature 39 which core is moved by oppositely acting coils 40 and 4|; When the coil 40 is energized more than the coil 4|, the armature 39 is moved to the left and 40 consequently the switch arm 33 is moved into engagement with the contact 3I. Likewise, when the coil I is energized more than the coil 49, the armature 39 is moved to the right and consequently the switch arm 33 is moved into engagement with the contact 32. Oppositely acting coils l2 and 43 control an armature or core 44 which is connected through a spring 45 to a pivoted switch arm 46. The switch arm 46 is adapted to engage contacts 41 and 48. When 50 coil 42 is energized more than the coil 43, the switch arm 46 moves into engagement with the contact 41, and when the coil 43 is energized more than the coil l2, the switch arm 46 is moved into engagement with the contact 48.

v This invention contemplates the use of a controller designated at 58, which responds to fire or furnace temperature and may take the form of the controller shown and described in my Patent No. 1,765,056 patented June 17, 1930. For purposes of illustration in this application I have shown this controller 58 to comprise a diaphragm 5| exposed to the fire within the boiler I 0. The diaphragm 5| which may be of spring bronze, engages a ring 52 which may likewise be made of spring bronze and the diaphragm 5| and the ring 52 are clamped between the housings 53 and 54. The controller 50 is suitably secured to the wall of the boiler I8. Secured to the diaphragm 5| by means of a nut and screw arrangement 56, is one end of a ribbon 55. The other end of the ribbon 55 is secured to the housing 54 by means of an adjustable tension spring 51. The ribbon 55 passes over a roller 58 suitably mounted in the housing 54. The ribbon 55 may frictionally engage the roller 58 or it may be secured thereto in any suitable manner as by a pin. The roller 58 carries an arm 59 having contacts 68 and 6| and a slider 62 mounted on the outer end thereof. The arm 59 extends through an opening in an insulating base 63. The insulated base 63 carries contacts 64 and 65 cooperating with the contacts 68 and 6| respectively carried by the arm 59. The insulated base 63 also carries a resistance coil 66 across which the slider 62 is adapted to slide. Upon an increase in fire temperature in the boiler I8 the diaphragm 5| flexes towards the right to move the arm 59 in a counter-clockwise direction as shown by the arrow designated H. Upon a decrease in fire temperature the disc 5| flexes towards the left to move the arm 59 in a clockwise direction as shown by the arrow designated C. The contacts 68, 6|, 64 and 65 are overlapping so that in cer- 4Il tain positions of the arm 59 contact 68 engages contact 64 and contact 6| engages contact 65. It is therefore seen that when the fire temperature is relatively low, contact 6| is in engagement with contact 65 and the slider 62 is in a down position with respect to the coil 66. Upon an increase in fire temperature the slider 62 moves upwardly and the contact 68 moves into engagement with the contact 64. Upon a further increase in fire temperature the slider 62 continues to move upwardly and the contact 6| is moved out of engagement with the contact 65.

A manual control switch is designated generally at 68 and may comprise a knob or handle 69 for operating a slider 18. In one position of the slider 18 it engages an elongated automatic contact 12. In another position the slider 18 engages an off contact 13. In still another position the slider 18 engages a resistance coil 1I and is adapted to be manually positioned along this resistance coil 1|.

A variable resistance is generally designated at 14 and comprises three resistances 15, 16 and 11. Slidably engaging these resistances 15, 16 and 11 are sliders 18, 19 and 88, respectively. The sliders 18, 19 and 88 are moved with respect to their resistance coils by rotation of a knob or handle 8|.

A pressure controller is generally designated at 82 and may take the form of a controller shown and described in application, Serial No. 743,377, filed by S. C. Shipley on September 10, 1934, now Patent No. 2,080,836 of May 18, 1937. For purposes of illustration in this application the pressure controller 82 is shown to comprise a pressure bellows chamber 83 connected by a pipe 84 to a source of steam pressure within the boiler I8.

Located in the bellows chamber 83 is a bellows which operates a plunger 85 which engages a lever 86. The lever 86 is pivoted on a knife edge 81 and is urged in a clockwise direction by means of an adjustable tension spring 88. The lever 86 carries a mercury switch 98. Upon an increase in pressure the lever 86 is moved in a counter-clockwise direction against the action of the tension spring 89 to move the mercury switch 98 to a circuit-breaking position. Upon a decrease in pressure the tension spring 88 moves the pivoted lever 86 in a clockwise direction to move the mercury switch 98 to a circuit-making position. The controller 82 is also provided with a diflferential spring arrangement 89 whereby the differential in pressure required to move the mercury switch 98 from a circuit-making to a circuitbreaking position and back again, may be varied.

A start and stop switch of usual design is designated at 9| and comprises a start button 92 and an off button 93. The start button when pressed inwardly is adapted to bridge contacts 84 and 95 and the stop button 93 when pushed inwardly is adapted to break contact between contacts 96 and 91.

A single throw double pole switch is designated at 99 and comprises switch arms I88 and IIII which are adapted to engage contacts I02 and I83 respectively.

A relay is generally designated at I84 and comprises a relay coil I85 which is connected in any suitable manner to switch arms I86 and I81. Upon energization of the relay coil I85, the

switch arms I86 and I81 are moved into engagement with contacts I88 and I89. Upon de-energization of the relay coil I85, the switch arms I86 and I81 are moved out of engagement with the contacts I88 and I 89 by means of springs or gravity or any other means, not shown.

A motor starter is diagrammatically desig- I nated at H8 and comprises a coil I II operatively connected in any suitable manner to switch arms H2. The switch arms II2 are adapted to engage contacts II3 upon energization of the coil III, and upon de-energization of the coil III the switch arms II2 are moved out of engagement with the contacts H3 in any suitable manner.

Line wires H4, H5 and H6 lead from some source of power, not shown. The contacts II3 oi the motor starter are connected by wires H1, H8 and H9 to the line wires II4, H5 and H6, respectively. The switch arms I I2 are connected by wires I28, |2I and I22 to motor I5 so that upon energization of the coil III of the motor starter II8 so as to move the switch arms II2 into engagement with the contacts II 3, the motor I5 and consequently the pulverizer I3 are placed in operation and powdered fuel is fed to the boiler I8 through the nozzle II and pipe I2.

A primary I23 of a step-down transformer I24, having a secondary I25, is connected across the line wires H4 and H5. One end of the secondary I25 is connected by wires I26, I21 and I28 to the left hand ends of the coils 48 and 42. In a like manner the other end of the secondary I25 is connected by wires I29 and I88 to the right hand ends of the coils 4| and 43. The junction of wires I26 and I21 is connected by a wire I3I to the contact 88 of the variable resistance 14 and the Junction of the wires I29 and I38 is connected by a wire I32 to one end of the resistance 16 of the variable resistance 14. One end of the resistance coil 11 is connected by wires I33 and I34 to the bottom end of the resistance coil 66 located in the controller 58. The

contact 19 of the variable resistance 14 is con nected by wires I and I36 to the upper end of the resistance coil 66. The junction of wires I33 and I34 is connected by a wire I31 to one end of the resistance coil 1| and the junction of wires I35 and I36 is connected by a wire I36 to the other end of the resistance coil H. The Junction of the oppositely acting coils 46 and 4| is connected by a wire I39 to the center of the resistance coil 15. The contact 18 cooperating with the resistance coil 15 is connected by a wire I46 to theslider 16. The automatic" contact 12 is connected by wires HI and I42 to the arm 59 of the controller 56. The left hand end of the coil 46 is connected by a wire I43 to the contact 32 carried by the sector plate 29 and the right hand end of the coil 4| is in a like manner connected by a wire I44 to the contact 3| also carried by the sector plate 29. The switch arm 33 is connected by a wire I45 and a resistance I46 to the junction of the oppositely acting coils 42 and 43. The line wire H5 is connected by a wire I41 to the switch arm 46. The contact 46 cooperating with the switch arm 46 is connected by a wire I48 to the limit switch 31 and the contact 41 is likewise connected by a wire I49 to the limit switch 36. The limit switch 31 is also connected by a wire I56 to one end of the field winding 26 and the limit switch 36 is also connected by a wire I5I to one end of the field winding 21. Field windings 26 and 21 are con nected together and to a wire I52 which extends to the line wire II4.

From the above wiring connections it is seen that the left hand ends of the secondary I23 and the coils 40 and 42 and the lower end of the resistance coil 66 are connected together and likewise the right hand ends of the secondary I25 and the coils H and 43 and the upper end of the resistance coil 66 are connected together. It is also seen that the junction of the coils 46 and M are connected to the slider 62 cooperating with the resistance coil 66. Therefore, the secondary I25, the oppositely acting coils 46, H, 42 and 43 and the resistance coil 66 are connected in parallel.

With the parts in the position shown in the drawing the slider 62 is in engagement with the center of the resistance coil 66 as a result of a normal average fire temperature, the slider 16 is in engagement with the automatic contact 12 to position the parts for automatic operation, the variable resistance 14 is adjusted in a midposition, the oppositely acting coils 46, M, 42 and 43 are equally energized with the result that neither field winding 26 or 21 is energized and the draft damper I1 is in a mid position causing a normal average draft to exist within the boiler I6.

Upon an increase in fire temperature or furnace temperature, the slider 62 is moved upwardly with respect to the resistance coil 66. This causes shunting or circuiting of the coil H to decrease the energization thereof and increase the energization of the coil 46. Due to this unbalanced relationship of the coils 46 and H, the switch arm 33 is moved into engagement with the contact 3I. Movement of the switch arm 33 into engagement with the contact 3| completes a circuit from the secondary I25 through wires I26, I21, I28, coil 42, resistance I46, wire I45, switch arm 33, contact 3| and wires I44 and I29 back to the secondary I25. Completion of this circuit causes short-clrcuiting of the coil 43 to decrease the energization thereof and increase the energization of the coil 42. This causes movement of the switch arm 46 into engagement with the contact 41 to complete a circuit from the line wire II5, through wire I41, switch arm 46, contact 41, wire I49, limit switch 36, wire I5I, field winding 21, and wire I52 back to the line wire II4. Completion of this circuit causes energization of the field winding 21 to operate the rotor 25 to move the damper I1 towards a closed position to retard the draft gization of the oppositely acting coils 42 and 43. 2

This balancing of the coils 42 and 43 causes movement of the switch arm 46 out of engagement with the contact 41 and into the mid-position shown in the drawing. This causes breaking of the circuit through the field winding 21 and consequently stops operation of the motor to maintain the draft damper I1 in its newly adjusted position.

Upon a decrease in fire or furnace temperature the slider 62 is moved downwardly with respect to the coil 66 which causes short-circuiting or shunting of the coil 46 to decrease the energization thereof and increase the energization of the coil 4I. This causes movement of the switch arm 33 into engagement with the contact 32 to complete a circuit from the secondary I25 through wires I29 and I36, coil 43, resistance I46, wire I45, switch arm 33, contact 32, and wires I43, I21 and I26 back to the secondary I25. Completion of this circuit causes short-circuiting of the coil 42 to decrease the energization thereof and increase the energization of the coil 43. This causes movement of the switch arm 46 into engagement with the contact 48 to complete a circuit from the line wire II5 through wire I41, switch arm 46, contact 48, wire I48, limit switch 31, wire I56, field winding 26, and wire I52 back to the line wire II4.

Completion of this circuit causes energization V of the field winding 26 to operate the rotor 24 to move the draft damper I1 towards an open position. Movement of the draft damper I1 towards an open position causes clockwise movement of the sector plate 29. When the draft damper I1 has been moved sufliciently far towards an open position as determined by the temperature of the fire or furnace, the contact 32 is moved out of engagement with the contact arm 33, to cause breaking of the circuit through the coil 43 to cause equal energization of the coils 42 and 43. Switch arm 46 is thereby moved out of engagement with the contact 48 and to its mid-position as shown in the drawing which breaks the circuit through the field winding 26 and stops operation of the motor controlled thereby. Draft damper I1 is therefore maintained in its newly adjusted position.

. If the draft damper I1 should be moved to its full closed position, the pin 34 causes opening of the limit switch 36 to prevent further closing movement of the damper I1. In a like manner, when the draft damper I1 is moved to its full open position, the pin 35 opens the limit switch 31 to prevent further opening movement of the draft damper I1.

' respect to the coil 66 to increase the energization of the coil 40 and decrease the energization of the coil H, which causes movement of the damper I1 towards a closed position. Therefore,

by moving the sliders 18, 19 and 80 towards the right with the slider 62 in a given position with respect to its resistance coil 66, the damper I1 is moved towards a closed position. Likewise, when the sliders 18, 19 and 80 are moved toward the left, more resistance is placed in circuit with the coil H and less resistance is placed in circuit with the coil 40, which produces the same effect as if the slider 62 were moved downwardly with respect to its coil 66. This increases the energization of the coil 4| and decreases the energization of the coil 40 to move the damper I1 towards an open position. Therefore with the slider 62 located in a given position with respect to its coil 66, movement of the contacts 18, 19 and 80 towards the left causes opening movement of the damper I1. Movement of contact 18 in either direction with respect to its resistance adds resistance to the circuits through both of the coils and 4| so that in case the sliders 19 and 80 are moved to either extreme position, burning out of the coils 40 and H is prevented. In this manner manual means are provided for adjusting the controlling action of the controller with respect to damper I1 so that the damper I1 may be positioned in a given number of different positions when the fire or furnace temperature is at a given value This provides an easy means for calibrating this portion of the control system.

The above detailed operation was set forth on the assumption that the slider 10 was in engagement with the automatic contact 12. Movement of the slider 10 out of engagement with the automatic contact 12 breaks the circuit through the slider '62 to prevent operation of the damper I1 by the controller 50. Since the lower end of the resistance coil H is connected to the lower end of the resistance coil 66 and the upper end of the coil 1| is connected to the upper end of the coil 66, movement of the slider 10 out of engagement with the contact 12 and into engagement with the resistance coil 1|, takes the control of the damper I1 away from the controller 50 and places it under the control of the manual control switch 66. Since the corresponding ends of the coils 1I and 66 are connected together, movement of the slider 10 upwardly with respect to the coil 1I, causes closing movement of the damper I1 in the manner above described and movement of the slider 10 downwardly with respect to the resistance coil 1I causes opening movement of the draft damper I1 in exactly the same manner as pointed out above. Movement of slider 10 out of engagement with the resistance coil H, and out of engagement with the automatic contact 12, and into engagement with off contact 13, prevents control of the draft damper I1 by either the automatic controller 50 or the manual controller 68. Therefore. manually operable means are provided for rendering the automatic control of the draft damper I1 inoperative, for placing the control of the damper I1 under manual control or for preventing either automatic or manual control of the draft damper I1.

A primary I of a step-down transformer I56, having a secondary I51, is connected across the line wires H5 and I I6, one end of the secondary I51 is connected by wires I58 and I59 to one of the electrodes of the mercury switch 90 of the pressure controller 62. The other electrode of the mercury switch 90 is connected by wires I60, I6I and I62 to the contacts 95 and 96 of the start and stop switch SL The start contact 94 is connected by a wire I63 to one end of the relay coil I05. The other end of the relay coil I05 is connected by a wire I64 to the other end of a secondary I51. Stop contact 91 is connected by wires I65 and I66 to the stationary contact 64 of the controller 50. and MI is connected by wires I61 and I68 to the contact I08 of the relay I04. Switch arm I06 associated with the contact I08 is connected by The junction of wire I42 I b a wire I69 to the junction of wire I63 and the relay coil I05.

Movement of the start button 92 into engagement with the start contacts 94 and 95 completes a circuit from the secondary I51 through wires I58 and I59, mercury switch 90, wires I and I6I, contact 95, start button 92, contact 94, wire I63, relay coil I05 and wire I64 back to the secondary I51. Completion of this circuit causes energization of the relay coil I05 to move the switch arms I06 and I01 into engagement with their contacts I08 and I09. Movement of theswitch arm I06 into engagement with the contact I08 completes a maintaining circuit from the secondary I51 through wires I58 and I59, mercury switch 90, wires I60 and I62, contact 96, stop button 93, contact 91, wires I and I66, contacts 64 and 60, arm 59, wires I42, I61 and I69, contact I08, switch arm I06, wire I69, relay coil I05 and wire I64, back to the secondary I51. This maintaining circuit maintains the relay coil I05 energized regardless of the position of the start button 92. However, included in this maintaining circuit is the pressure controller 92, the contacts 60 and 64 of the controller 50 and the stop button 93 of the start and stop switch 9I. If the boiler pressure should become too high so as to move the mercury switch to a circuit breaking position, or if the fire or furnace temperature should decrease below a given value so as to move the contact 60 out of engagement with the contact 64, or if the stop button 93 should be pressed to break contact between the contacts 96 and 91, the maintaining circuit through the relay coil I05 would be broken to cause de-energization of the same to move the switch arms I06 and I01 out of engagement with the contacts I08 and I09. Since the starting circuit for the relay coil I05 is completed through the starting button 92, start button 92 must again be moved into engagement with the start contacts 94 and 95 to again cause energization of the relay coil I05. Therefore, the relay coil I05 may only be initially energized upon manipulation of the start button 92 and will only be maintained in an energized condition when the boiler pressure is normal and when the condition of the fire is normal.

The contact I09 of the relay I 04 is connected by wires I10 and HI to the line wire II5. The switch arm I01 cooperating with the contact I09 is connected by a wire I12 to one end of the coil III of the motor starter H0. The other end of the coil III is connected by wires I 10 and I14 to the line wire IIO. Therefore, upon energization of the relay coil I05 in the manner above described, to move the switch arm I01 into engagement with the contact I00, the coil III is energized to move the switch arms II2 into engagement with contacts IIO to cause operation of the motor I5 and the fuel pulverizer I3 to supply fuel to the boiler I0.

The switch arm I01 is connected by a wire I15 to one end of a primary I16 of a step-down transformer I11, having a secondary I10. The other end of the primary I16 is connected by a wire I19 to the junction of wires I10 and I14. Therefore, when the relay coil I05 is energized to move the switch arm I01 into engagement with the contact I09, the transformer I11 is energized simultaneously with the motor starter IIO. One end of the secondary I10 is connected by a wire I00 to the junction of wires I and I 50. The stationary contact 05 of the controller 50 is connected by a wire IOI to an indicating device I 02 which may take the form of an alarm or bell of usual design. The indicating device I02 is connected by a wire I00 to the other end of the secondary I10. When the fire temperature decreases to a given value so as to cause simultaneous engagement of overlapping contacts 60, 04 and BI and 65, a circuit is completed from the secondary I10 through wires I00 and I50, mercury switch 00, wires I00 and I62, contact 06, stop button 03, contact 91, wires I65 and I06, contacts 64, 60, 0I and 05, wire IOI, alarm I02 and wire I03 back to the secondary I10. Completion of this circuit causes sounding of the alarm I02 to notify the attendant in charge of the combustion control system that the condition of the fire within the boiler I0 is abnormal.

Summarizing briefly that portion of the combustion control system relating to the fuel feeding mechanism, when the fire within the boiler I0 is extinguished, the arm 59 is in a down position whereby contacts 00 and 04 are broken and contacts 6| and 05 are made. To start operation of the fuel supplying means, start button 92 is pressed inwardly to complete the above referred to starting circuit which causes starting of the fuel pulverizer I0 with consequent delivery of pulverized fuel from the boiler I 0. This pulverized fuel is ignited in any suitable manner, not shown, and from that point the fire temperature will tend to increas.' An increase in fire temperature causes upward movement of arm 50 to move the contact into engagementwith the contact 64, it being remembered that the contact 6I is still in engagement with the contact 65.

Therefore, when the contact 00 moves into engagement with the contact 64, the circuit'through the alarm is completed and the alarm is sounded to notify the engineer in charge of the combustion control system that contact has been established between the contacts 00 and 04. The engineer in response to this alarm releases the start button 92 and since the contact between the contacts and 64 is established, the maintaining circuit is completed to maintain the fuel feeding means in operation. Continued rise in fire temperature causes positioning of the draft damper I1. If by reason of clogging of the nozzle II or by any other reason, the fire within the boiler I0 should decrease through a predetermined low value, the arm 50 is moved downwardly to make contact between the contacts 6I and to sound the alarm I 02 to notify the engineer of faulty operation of the fuel, feeding means. If the faulty operation is not corrected, the arm 59 continues to move downwardly to break contact between the contacts 60 and 04 to break the above referred to maintaining circuit to shut down the fuel feeding means, which can only be started again after manual manipulation of the start button 92.

The contact I02 of the single throw double pole manual switch 90 is connected by a wire I04 to the junction of wires I61 and I00. The switch arm I00 is connected by a wire I05 to the junction of wires I65 and I66. By reason of these connections it is seen that the manual switch 09 is connected in parallel with the contacts 60 and 04 so that when the switch arm I00 is moved into engagement with the contact I02, the contacts 60 and 64 are rendered inoperative to control the fuel pulverizer I0. In this manner the safety function of the controller 50 may be eliminated. As a safeguard to notify the engineer in charge that the safety function of the controller 50 is rendered inoperative, the switch arm IOI is connected by a wire I01 to a light I00 which in turn is connected by a wire I00 to the junction of wire I10 and the primary I16. The contact I00 cooperating with the switch arm I M is connected by a wire I00 to the junction of wires I10 and HI. By reason of these connections when the switch arm I00 is moved into engagement with contact I02 to render the safety function of the controller 50 inoperative, the light I60 is lit to notify the engineer of this fact.

From the above it is seen that I have invented a novel combustion control system wherein a draft regulating means is positioned in accordance with fire or furnace temperatures, wherein a fuel supplying means is manually placed in operation and is under the control of safety devices so that if the fire should assume an abnormal condition or if the boiler pressure should exceed a given amount, the fuel supplying means will be rendered inoperative, wherein the draft regulating means may be adjustably positioned with respect to the fire or furnace temperature, wherein means are provided for rendering the automatic control means for the draft regulating means inoperative and placing the draft regulating means under manual control, and wherein an alarm system is provided for notifying the engineer when the condition of the fire is abnormal.

Although for purposes of illustration I have disclosed one form of my invention, changes and modifications thereof may become apparent to those skilled in the art, and consequently the scope of this invention is to be limited only by the scope of the appended claims and prior art.

I claim as my invention:

1. In a combustion control system, in combination, means forming a combustion chamber, means for supplying. fuel to said combustion chamber, means comprising a manually depressible switch device for initiating operation of said fuel supplying means, said switch being closed only when held in depressed position, means responsive to a condition indicative of the presence of combustion in the combustion chamber, said last means being operable to cause continued operation of said fuel supplying means independently of said switch'when proper combustion occurs in the combustion chamber, signal means for automatically indicating when operation of said fuel supplying means is independent of said switch whereby uponstarting of the system the presence of a human operative is required until proper combustion is assured by the signal whereupon the manually depressible switch may be released.

2. In a combustion control system, in combination, means forming a combustion chamber, means for supplying fuel to said combustion chamber, means comprising a manually depressible switch device for initiating operation of said fuel supplying means, said switch being closed only when held in depressed position, means responsive to a condition indicative of the presence of combustion in the combustion chamber, said last means being operable to cause continued operation of said fuel supplying means independently of said switch when proper combustion occurs in the combustion chamber, signal means for automatically indicating when operation of said fuel supplying means is independent of said switch whereby an operative may then release the switch, and said condition responsive means comprising means operative upon an increase of combustion to terminate the signal given by said signal means whereby the operative is apprised of the establishment of combustion and of the satisfactory progress of combustion thereafter.

3. In a combustion control system, in combination, means forming a combustion chamber, means for supplying fuel to said combustion chamber, means comprising a manually depressible switch device for initiating operation of said fuel supplying means, said switch being closed only when held in depressed position, means responsive to a condition indicative of the presence of combustion in the combustion chamber, said last means being operable to cause continued operation of said fuel supplying means independently of said switch when proper combustion occurs in the combustion chamber, signal means for automatically indicating when operation of said fuel supplying means is independent of said switch whereby an operative may then release the switch, and said condition responsive means comprising means operative upon an increase of combustion to terminate the si nal given by said signal means whereby the operative is apprised of the establishment of combustion and of the satisfactory progress of combustion thereafter, and said condition responsive means being arranged to cause said signal means to give a signal and to terminate said signal to indicate substantial termination of combustion in said combustion chamber.

4. In a combustion control system, in combination, means forming a combustion chamber, means for supplying fuel to said combustion chamber, draft regulating means for said combustion chamber, means comprising a manually depressible switch device for initiating operation of said fuel supplying means, said switch being closed only when held in depressed position, means responsive to the fire condition in said combustion chamber, said last means being operable to cause continued operation of said fuel supplying means independently of said switch when proper combustion occurs in the combustion chamber whereby said switch may be released, said condition responsive means includ ing means operable to assume control of the draft regulating means when operation of said fuel supplying means becomes independent of said switch, signal means for automatically indicating when operation of said fuel supplying means is independent of said switch and said condition responsive means is controlling said draft regulating means, said condition responsive means causing the signal given by said signal means to be terminated after an increase in combustion in said combustion chamber, said condition responsive means relinquishing control of said draft regulating means substantially upon the termination of combustion, and said condition responsive means causing said signal means to indicate when said condition responsive means relinquishes control of said draft regulating means.

LEWIS L. CUNNINGHAM.

Images