US2212352A - Multiple fuel burner system - Google Patents

Description

Aug. 20, 1940. R. J. PLEIN MULTIPLE FUEL BURNER SYSTEM Filed Aug. 8. 19:58

2 Sheets-Sheet 1 Aug. zo, 1940.

R. J. PLElN MULTIPLE FUEL BURNER SYSTEM y Filed Aug. 8, 1958 2 Sheets-Sheet. 2

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Patented Aug. 20, 1940 PATENT OFFICE MULTIPLE FUEL BURNER SYSTEM Ralph Plein, Chicago, lll., assignor to Drying Systems, Inc., Chicago, Ill., a corporation .ofA

Illinois Application August 8, 1938, Serial No. 223,658

-s claims. 'Ihe invention relates generally to fuel burners and more particularly it relates to fuel burning systems having a plurality of individual fuel burners.

A The primary object of the present invention is to provide a multiple burner'starting and control system which is simple and economical in construction and operation. 1

Another object is to provide a multiple burner starting and control system having an electric ignition means for all of the individual burners wherein the customary duplication of equipment for each burner unit is rendered unnecessary.

More specifically, it is an object of the present invention to provide such a multiple burner system wherein a single ignition transformer of relatively small size serves to supply high voltage ignition current for all of the individual burners without overload upon the single transformer. Another object is to provide a new and improved multiple burner system wherein a single safety control system governs a relatively large.

number of main burner units.

A further object is toprovide a multiple burnerA system wherein a single control system acts through a plurality of parallel main burner control circuits to effect control of a plurality of main burner units.

Other objects and advantages will become apparent from the following description. taken in connection with the accompanying drawings, in

In the form chosen for disclosure herein thev invention is embodied in a multiple burner system adapted for supplying heat to the various units of an industrial baking or drying installation. 5 Such an installation includes suitable drying ovens. baking ovens or other chambers through which heated gas such as the productsof combustion of the heaters, or air heated by the heaters, is forced or drawn by suitable power driven ym fans. Thus in Fig. 1 of the drawings there is diagrammatically illustrated a multiple burner system adapted for use with such an industrial installation. there being a plurality of main burners Ilwhich inthe present instance are arranged in two groups Il and l2.

With this arrangement the group. Il may be used to supply heat for one chamber of the system and the group I 2 for another chamber. Thus the group il of main burners i0 is supplied with fuelfrom a supply pipe Il which is controlled I by a valve il. The valve il is normally closed and has an actuator such as a solenoid I5 which opens the valve I4 when energized. The group I2 is fed from a similar supply pipe It under the control of a similar valve Il and actuator i8. l0

Each main burner lli has a pilot burner 20 which is shown diagrammatically in Fig. 1, but

which in actual practice is closely associated physically with respect to its related main burner Il). The pilot burners 20 are supplied with a 16 fuel such as gas from a common fuel line 2i i under the control of a normally closed pilot fuel valve 22. An electrically operable actuator such as a solenoid 23 is operable to open the valve 22 when energized. 2.

The pilot burners 20 are each provided with anelectrical igniting device such as a spark plug 25, which spark plugs 25 are shown diagrammatically in Fig. 1, although in the actual installation each plug is mounted so that its spark points are log.

, cated in the path of the pilot fuel as it discharges through the related pilot burner 20.

In the use of drying or baking installation of the type with which the present burner system is adapted to be employed, it is desirable that 30 the various chambers be purged ofaccumulated gases prior to the starting of the various burners;

` gases from the various chambers of the system;

while the energizing circuits for the actuators of a the main fuel valve means are rendered dependent upon'the energization of the pilot valve actuator. f

As shown in Fig. l, actuating power for the various'electrically operated elements'of the sysw tem' is taken from leads L1 and In which by means of a main switch 2C may be `connectedto leads In and L4 respectively. These leads L: and

L4 may include fuses 21, if desired. The lead In ""cggstitutes the common power wire of the presu.

ent system and is connected to one terminal of the pilot gas valve actuator 23 by a wire 28, while the circuit from L; to the other terminals of the actuator 23 includes various safety switch means which insure proper operation ofrelated elements of the installation prior to opening of the pilot gas valve 22.

Thus the present circuit from the line L; to the valve actuator 23 includes switch means 30 which is responsive to pressure in the gas main to make contact lonly if a predetermined gas pressure exists in the main. This switch means has one terminal connected to lead L4. `'I'his circuit also includes a pair of similar suction responsive switch devices 3| and 32 connected in series by wires 33 and 35i to the other terminal of the switch means 3G. The two switch devices 3l and 32 are of the type having rockable flap members 8l' which are responsive to air ow to close the associated switch. The switch device 3l is preferably mounted so as to be responsive to air flow created by. the stack fan (not shown) of the srstem, while the .switch 32 is preferably mounted so as to be responsive to air ow created by the exhaust fan (not shown) of the oven or other chamber which is to be purged of gases.

In the present system, the purging fans must operate for a predetermined time prior to the starting of the various burners, and to insure this delay, the circuit from the lead Lt is associated with a time delay relay 35. The relay 35 has a y time delay actuating circuit including a coil 35 one end of which is connected by a'wire 81 to the other terminal ofthe switch device 32 while the other end of the coil 36 is connected by a wire 38 delay circuit for a predetermined time, a switch arm 39 of the relay is actuated to engagea contact 40 of the relay, the switch arm 39 being connected by a jumper wire M to the wire 31.

From the contact 40, a wire 62 extends to one terminal of a normally closed push button switch d3, the other terminal of which is connected by wires M, B5 and 6, a normally open relay switch 51 and a wire 48 in series to the other terminal of the pilot valve actuator 23. The relay switch G1 is of the induction type having one coil t@ connected at one end to wire and at its other end to lead Le by'means of a wire 5d. The other or control coil' 52 of the relay switch d1 operate when a circuit is closed through lthe coil 52, to cause the switch il to be closed, and this operation is manually induced by closure of a normally open push button switch 5t.' The contacts of this switch 53 are connected to opposite ends of the control coil 52 by wires 54, 55 and 56.

When the purging cycle has been completed so as to close the switch 39 of the time delay relay 35, the system is conditioned' for starting of the pilot burners 28. This proper conditioning ist visually indicated by an indicator light 8B connected between wire t5 and lead La. The pilot starting button 53 may then be depressed so as to energize the pilot valve actuator v23, and

As uch energization is visually indicated by an invices are in the form of thermostatically actu- -l ated switches 'each arranged to be closed by the heat from the pilot flame with which it is associated. 'Ihe several detecting devices 80, therefore, are connected in series by wires 5|, 62 and 63 across the ends of the coil 52. lWith this construction, the detecting devices 68 are associated one with each burner 20 so as to be subjected to the heat thereof, and hence the failure of one of the burners 28 during normal operation of the system 'will act to open the holding circuit through the coil 52. This permits. opening of the switch B1 so as to cause shutting down all of the burners I8 and pilots 20 as will be hereinafter all energized from the secondary of a singletransformer 65, of relatively small size and this is accomplished without undue load on the transformer.- l'.ihe primary 0f the transformer B5 is v connected at one end to the line Lc by a wire 66 while its other end is connected by wires 81, B8 and S9, a normally closed sw'itch 10, and wires 1i, 12 and 13'all in series to the wire 48. Thus when kthe pilot fuel valve 22 is opened; the transformer Y 55 is simultaneously energized, Y

In order that the single transformer may serve to energize all of the spark plugs 25 without unduly loading the transformer, means is provided whereby the output potential from the secondary coil 85 is applied in, rapid succession to the several spark plugs. This end is attained' through the cooperation of a distributor device 15 which is shown in detail in Figs. 2 and 3 of the drawings. 'I'he distributor device 15 comprises a plurality of circumferentially spaced contacts 16 each connected by a wire'11 to the center terminal of oneof the spark plugs 25. Centrally of the stationary contacts 1E a rotatable wiper arm 18 is mounted so as that in rotation of the arm 1B a circuit is made successively with each of the contacts 1S. The central or rotatable wiper arm 18 is connected by awirel to one end of the secondary coil $5' while the other end of the.. coil is grounded by a wire 8. The rotatable armv 18 of the distributor device is driven by an electric motor 8| which is energized simultaneously with the transformer 65 by wires 82 and 83 which-connect'lthe motor terminals to the lead In and the wire 68 respectively. In the form herein illustrated the, distributor device 15 is mounted directly on one end of the motor 8|, there being a connector' housing 85 secured to the motor housing by screws 85 so as to surround the projecting end of the motor shaft 81. On the open face of the housing 85 a mounting plate. is fastened by screws 89, and an extension sleeve 90 connected ,to the 'shaft `81 as at 8| projects through a 4central bearing openingin the plate 88. 'I'he wiper. arm 18 is mounted and keyed to the sleeve 80, and the several contacts 16 are mounted in an insulating cap 92 which houses the arm 18 and is secured to thel .dil

plate 88 by screws 93. Each contact 18 is formed l as a part of a connecting socket 94 so that suitably formed ends of the wires 'l1 may be inn asiassa serted into the sockets and thereby connected to the contacts. A similar connecting socket l is provided centrally of the cap 02 to receive the wire 10, this socket 00 having a stationary terminal 01 positioned centrally of the inner face of the cap .02 for constant engagement by a spring contact 00 carried on the wiper arm 10. On the end of the .arm 'l0 and in circuit with the rontact 00, a resilient wiper contact |00 is mounted so as to cooperate with the contacts 'I6 successively as the arm I0 is rotated. lWith the distributor device operating at motor speed, the output of the transformer 00 is applied to each spark plug 25. in rapidly reoccurring pulses so as to create a series of sparks or igniting arcs at each plus. 'I'he succession of arcs created at each plug is such as to ignite the pilot fuel with the same efllciency/asvif the current were appliedgcontinuouslyto each plug, and this result s economically attained by the use of but a single transformer.

As soon as the pilot burners 20 have been ignited,y the systemlis in condition for starting of the main burners I0, and as hereinbefore pointed out, such starting of the main burners I0 is rendered dependent upon the proper energization of the several operative elements of the pilot burner starting means. Thus starting of the main burners |0 is attained through an energizing circuit which includes the wire ,12, this wire being energized only when the pilot starting relay Il has been actuated. To this end wires |0| and |02 extend in series from the wire 12 to one contact of a normally open switch |00.

vFrom the other terminal of the switch |00 wires |04 and |05 extend, and the main fuel valve actuators i5 and I0 are connected between wire |05 and lead Is so that when the switch |00 is closed, the main fuel valve actuators maybe energized.

As herein shown the valve actuators I0 and l0 are on separate parallel circuits from the wire |05 and lead La, and each of these circuits preferably includes safety devices associated with the chambers heated by the burners.

Thus the lead La isjconnected to one terminal of the actuator I0, while the other terminal is connected to the Wire |00 by wires |00 and |01 which have safety devices |00 and |00 in series therewith. The safety device |00 preferably comprises a limit switch associated with the chamber heated by the group |2 of burners, while the safety device |00 comprises a flow switch similar to the switches 0| and 32 and sensitive to the flow of air created by the supply fans associated lead La. A second or control coil |20 is provided in the relay llifand when a circuit is completed through the coil |20 during energization of the coil the relay is" actuated. The coil |20 is therefore connected by wires |2| and |22 5 to the terminals of the push button switch H6, and a holding circuit for the coil |20 is provided by wires |23 and l|20 from the wires |2| and |22 respectively to the contacts oi a normally open switch |25. The switches 10, |03 and l0 |25 all constitute parts of the relay ||5 and are actuated thereby.

Since the switch '|0 is rocked to its open position by actuation of the relay H5, the Icircuits to the transformer and to the motor 0I are broken 15 and the operation of the electric ignition is thereby terminated automatically when the main burners I0 are started.-

The relay switch 45, of course, constitutes the primary safety relay of the present multiple burn- 20 er system, and when a flame or heat failure in any of the pilot burners is detected by the assoelated detector the holding circuit of the relay switch 06 is broken and the switch returns' to its normal open position so as to cut oil the 25 energizing circuits of both the main and pilot burnerV valve actuators. These valves then re.- turn to their normal closed position and the operation of all the burners is stopped.

Since the single main safetyfcontrol relay 01 30 parallel circuit such as that formed between the 40 Wires and H2; or` that a larger number of groups such as the groups I| and I2 ofy main burners could be similarly controlled from. the control wires La and |05. Hence the single starting mechanism which insures proper sequence of 45 the various operations involved in the starting of the burners may serve to control a. large number of main 'burner unts. 'I'he present/arrangement is particularly flexible-finfusef the reason that all of/theiriers |0 need not be set in opera- 50 tion unless such operation is desirable. Thus, if the user wishes to employ only the burners of group I2, it is only necessary to turn off theblowers or fans/which cause closure of the safety control/device |00. By'this action the circuit to y55 with said chamber. When the valve actuator/Il//the fuel valve actuator I0 is broken, with the is energized, this condition is visuallLsllowr4 by an indicator light |I0 connecteclbetweenlead La and the wire I0! f/ MJA/similar/pllel circuit to the valve actua;

tor I0 is formed by a wire from the lead Ia to one terminal of the actuator and similar wires |00' and |01 safety devices |00' and |00' and a wire ||2 inv series from the other terminal of the actuator I5 to the wire |05. A. similar indicator such as a light H0' is provided lbetween the wires 4and |00'.

The starting of the main burners I0 is prefably controlled manually, and to this end the switch |03 is provided as a part of a relay y||0 which is actuated from its normal position of Fig. l under the control of a push button'switch` H0. As herein shown the relay Iii is of the induction type having a. coil connected by result that fuel to the burners of the group |2 isk shut oil. In such a case, the pilots associated with this group would continue to burn so as to insure ignition of the main fuel upon reclosure so plugs for igniting said pilot burners, means for supplying fuel to said pilot burners including an electrically actuated control valve and an energizing circuit for 'said valve, means for supplying high potential to said spark plugsincluding a distributor and a driving motor therefor, said distrlbutor being operable to energize said`plugs in rapid succession when driven by said motor, a common control means for controlling the motor and said valve energizing circuit, means for supplying fuel to said main bui-nersincluding at least Velectrically actuated control valve and an energizing circuit for said valve, means for supplying high potential to said spark plugs including a high tension current source. a distributor and a driving motor therefor, said distributor being operable to energize said plugs in rapid succession when driven by said motor, a common control means for controlling the motor, said high tension current source and said valve energizing circuit, means for supplying fuel tovsaid main burners including at least one electrically actuated valve and an energizing circuittherefor, and

other common control means operable to control the energizing circuit for the main burner fuel supply means and to control said motor and said high tension source.

3. In a multiple burner system having a plurality of main burners and a plurality of pilot burners therefor, means operable to start said pilot burners including fuel supply valve means and electrical ignition means therefor, said ignition means including spark plugs for the individual pilot burners, a transformer and a motor driven distributor operable to apply the output of said transformer to said plurality of spark plugs in rapid succession, said motor and said transformer being energized by said pilot burner starting means concurrently with the operation of the pilot fuel supplyvalve means, means for starting said main burners including fuel supply means, and means operable as an incident to the operation of said main burner starting means to deenergize said electrical ignition means.

4. In a multiple burner system having a plurality of main burners and a plurality of pilot burn# ers therefor, means operable to start said pilot burners including fuel supply valve means and electrical ignition means therefor, said ignition 'means including ignitiondevices for each of the individual pilot burners, a transformer and a motor driven distributor operable to apply the out-i put of said transformer to said individual ignition devices in rapid succession, said motor and said transformer being energized by said pilot burner starting means concurrently with the operation of the pilot fuel supply valve means, means for starting saidmain burners including fuel supply means, and means operable as an incident to the operation lof said main burner starting means to deenergize said electrical ignition means.

5. In a multiple burner system having a plurality of main burners and a plurality of pilot burners therefor, means to start said main burners including fuel supply means and control valve means therefor, means operable to start said pilot I burners including fuel supply means and electri-v cal ignition means therefor and common starting means for said fuel supply means and said electrical ignition means, said ignition means including individual ignition devices for the` individual pilot burners, and a source =of current and a motor driven distributor operable to apply current from said source to said individual ignition devices in rapid succession, said motor and said source.be-

ing primarily controlled by said pilot 4burner starting means and secondarlly controlled by said 6. In a multiple vfuel burner system having a plurality of main burners and a plurality of pilot burners, fuel supply means for said main burners including normally closed main valve means and electrical actuating means operable .when energized to open said main valve means, fuel supply means for said pilot burnersincluding normally closed pilot valve means and-electrical actuating means operable when energized toopen said pilot valve means, electric ignition means for initiating combustion of the pilot fuel including a plurality of spark plugs associated one with each pilot burner, a transformerand a motor driven distributor operable to apply the output of transformer to said'spark plugs in rapid succession, a common energizing circuit for said pilot valve actuating means, said motor and said transformer including a first manually controlled circuit closing means, and means for energizing said main valve actuating means comprising Va main valve circuit primarily controlled by said first manual circuit closing means and secondarily controlled by a second 25 manually controlled circuit closing' means, said second circuit closing means being operable when said main valve circuit is closed to open the circuit to said motor and said transformer.

7. In a multiple fuel burner system having a plurality of main burners and a plurality of pilot burners, fuel supply means for said main burners includingnormally closed main valve means and electrical actuating means operable when energized to open said main valve means, fuel supi ply means for said pilot burners including nor- -mally closed pilot valve means and electrical actuating means operable when energized to open said pilot valve means, electric ignition means for initiating combustion of the pilot fuel including a plurality of ignition` devices associated one with each pilot burner, a source of ignition cur-- rent and a motor Vdriven distributor operable to apply current from said source to said ignition de- Y vices in rapid succession, circuitmeans for energizing said pilot valve actuating means and said motor and for controlling said source including a first manually controlled circuit closing means, `means for energizing` said main valve actuating ciated one with each of said pilot burners, and a 60 holding circuit for maintaining said first circuitA closing means in its circuit closing relation and governed jointly by said plurality of detecting de- 8. In a multiple fuel burner 'system having a plurality of main burners and a plurality of asson ciated pilot burners, fuel supply means for said main burners, fuel supply means fox-.said pilot burners, means for igniting said pilot burners including electric ignition means for initiating combustion of the pilot fuel having a plurality of Vindividual electric igniting devices associated one with each pilot burner, a transformer, a motor driven distributor operableto apply the output succession, means for starting said pilot` burners including a control for energizing said motor and said transformer and for operating said pilot fuel supply means, and means for starting said main burners primarily controlled by said pilot burner starting means and operable upon said control when said main burnersare started to stop said motor and deenergize said transformer.

9. In a multiple fuel burner having a plurality of main burners, and a plurality of associated pilot burners, a plurality of parallel control circuits each operable to govern the operation rof one or more of said main burners, each of said parallel circuits including one or more safety switch devices responsive to operatingconditions of the main burner controlled by its circuit, a common safety switch. means, governing means for said common safety switch means including safety devices responsive to the operating conditions of each of said pilot burners and operable to actuate said common safety switch means to one relation when all of said pilot burners are operating and to another relation when any one of said pilot burners is inoperative, and a safetyv circuit governed by said common safety'switch and connected to all of said parallel control circuits in governing relation thereto.

RALPH J. PLEIN,

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