US2286156A

US2286156A - Burner control system

Info

Publication number: US2286156A
Authority: US
Publication date: 1942-06-09
Anticipated expiration: 1959-06-09

Description

June e, 1942. E. PETERSEN 2,286156 BURNER CONTROL SYSTEM Filed April- 22 1959 nnentoz- Arnold. E 1e3: Grpem...

' Pa8tented Jung 9, 1942 UNITED STATES PATENT OFFICE 2,286156 BURNER CONTROL SYSTEM Arnold E. Petersen, New York, N. Y. assignor tb Minneapolis-Honeywell -Regulator Company, Minneapolis, Minn., a corporation of Delaware Application April 22, 1939, Ssiial N0. 269,355

15 Claims. (GI. 158117.1)

'that in order to prevent the unnecessary cousumption of fuel by the pilot burner during the summer months, the pi1ot burner must be turned ofl'. Inasmuch as this may be a hazardous operatin and since the relighting of the pilot burner is particularly hazardous, it is the usual custom of the ga.s company to insist upon shutting 01T and relighting the pilot burners. Inasmuch as a demand for relighting of the pilot burner in the fall usually occurs upon the existence of the first cold day, the greater majority of the austomers desire their pilot burner lighted ab approximately the same time. Since this is obviously impossible, considerable inconvenience is encountered by the customer. As a. result of these difliculties a. syste'm has been employed in many cases in which the pilot burner is reignited each time that there is a ca]! for heat. The difliculty with such a system is tha.t the igniting apparatus when so used has inherently a relatively short life al'1d the apparatus, in order I;o be sa.fe under all possible conditions, must be relatively complicated.

II: has been proposed to overcome these difficulties by employing a system wherein the pilot burner is normally constantly burning but may be conveniently shut down whenever desired and reignited in a convenient manner. The present invention is concerned with an improved form of such a system.

An object of the present invention is to provide a. system having a main burner and conoperation, the pilot valve is automatically reopened and the pi1ot burner is reignited.

A further object ofthe present invention 1s I:o p rovide such a, system in which upon the pilot valve being opened, the igniting means is rentim6 sufficient to insure igniti on cf the pilot burner. v

A fu-rther object of the present invention 1s to provide such a system wherein the pilot burner va1ve is normally held open by a catch and in which an electrothermal motor means is provided for 'releasing the catch.

Other objectgof the invention will be apparent from a consideration of the accompanying specification, claims and drawing in which the invention is shown in schematic form.

Referring to the drawing a. conventional gas burner is represented by the refergnce numeral III. The burner III is supplied with gas through which is connected to a. pipe I5 leading I;o a suitable source of gas (not shown).

Associated with the main burner I II is a pilot burner I'I, this pilot burner is connected through a pipe I8, a 'valve I9 and a pipe 28 with the pipe I5 connected to the inlet side .of valve I4. Mounted on the pilot burner I'I is a bimetallic element 22 which upon being heatedis adapted to move into engagement with a fixed contact 23. The pilot burner I'I is provided with a slot adjacent the bimetalllc element to provide an auxiliary fiame 25 which plays upon the bimetallic element 22 when the pilot burner is ignited. Located adjacent to the upper end of the pilot burner I'I is an igniter 24 which consists of a.

coil of high resistance wire. Upon energization of this coil, the same is raised to incandescence andserves f;o ignite ar;y gas issuing from the pilot burner.

A flow of gas to the main burner III is controlled by the valve I 4. 'Ihis valve is provided with a. valve stem 21 I;o which is secured a solenoid core 28. The solenoid core 28 coopeiates with a solenoid winding 29. The upper end cf valve stem 21 is adapted to engagea switch blade 30 which in turn is adapted to er igage a. fixed contact; 3I.

' Upon energization of the solenoid winding 29,

dered operative for a predetermined period of the core 28 is moved upwardly to open the valve and I:o move switch blade 38 into engagement with contact 3I. II: is to beunderstood that the arrangement consistsing of solenoid winding 29 and core 28 is shown purely for illustrative purposes and that any 0ther electrical actuating means can be used instead.

The valve I9 serves as the pilot burner valve t0 control the flow of fuel to thg p'ilot burner I'I.

'I'his valve is provided with a valve stem 33 which extends through a bimetallic element 34. The stem 33 is provided with a cbllar at its upper end so that upon inward movement of the bimetallic element 34 the latter engages the collar 35 and moves valve stem 33 upwardly to valve open position. A heater 36 is located adjacent the blmetallic element 34 for the purpose of heating the same to efiect such upward movement thereof. The left band end of the bimetallic element 34 is rigidly secured to a suitable supporting meanS 31 whereas the right hand end is free to move. The bimetallic element 34 carries

contacts

39 and 32 which are adapted to engage with fixed contacts 40 and 4l upon upward movement of element 34. The element 34 is shown in its normal cold position.

The bimetallic element 34 is adapted to cooperate with a hell crank lever 42 which is pivotally mounted at 43. The downwardly extend- Ing arm 44 of the hell crank lever is provided with a portion 45 adjacent the lower end which is slightly wider than the upper portion 015 arm 44. Between the portion 45 and the 1 1pper portion of arm 44 -is an inclined portion 46 Which terminates with a horizontal shoulder 41. Secured to the arm 44 at the lower end thereof is a flexible contact arm 50 which is adapted to engage a. fixedcontact 54. In the position in which the various parts are shown the contact arm 50 is in engage- .ment with contact 54. Upon the bimetallic element 34 being heated to move upwardly, it will eventually reach the shoulder 41 permitting the arm 44 to move in a clockwise direction until the end of the bimetallic element 34 engages the edge of the arm 44 above the shoulder 41. Because of the narrower width of arni 44 at this point contact arm 50 no longer is in engagement with the contact 54. A spring48 is secured at one end to the contact arm 44 and at its other end to a 'flxed support 49. The spring 48 serves to bias arm 44 in a clockwise direction so that upon bimetallic element 34 moving ofl of the inclined portion 46, arm 44 is abruptly moved in a clockwise direction.

The hell crank lever 42 is further provided with a horizontal arm 5I. 'I'his horizontal arm is adapted to cooperate with a second bimetallic element 52 which has a pusher member 53 secured thereto. The pusher member 53 bears against arm 5l. The end of bimetallic element 52 opposite to that to which pusher member 53 is secured, is secured t o a fixed support 55. Located adjacent to bimetallic element 52 is an-electrical heating element 56. The element 52 is so disposed that upon 'being heated, the left band end thereof is deflected downwardy to move arm 51 in a counter-clockwise direction.-

The valve 21 is normally under the control of a condition responsive switch which ls shown for purposes of illustration as a room thermo-' stat. 'I'his room thermostat comprises a bimetallic element 61 to which is secured a flexible contact arm 62 and a relatively rigid contact arm first engagement of contact arm 62 with contact 63. The bimetallic element 6I is adapted to move contact arms 62 and 63 to the left upon a temperature fall. Contabt arm 62 is adapted to engage a fixed contact 64 and contact arm 63 is adapted to engage a contact 65. The spacing between contact arm 63 and contact 65 is slightly 60 is provided with means for adjusting the same. This means is shown as comprising a lever arm 66 which is secured to the bixnetallic element 6l. The bimetallic element 6l is pivotally mounted at 61 so that upon movement of the lever arm 66, the bimetallic element 6I is rotated about pivot point 61 thereby varying the temperature at which the engagement 015 contact arms 62 and 63 with contacts 64 and 65 is effected. The lever arm 66 is adapted to cooperate with a scale 10 bearing suitable indicia to indicate the temperature setting of the thermostat. Located adjacent to the thermostat 60 is a switch blade 1I which is adapted to be moved into engagement with a flxed contact 12. The blade 11 is so positioned with respect t'o contact arm 62 that upon the arm 66 being mo'ved to the extreme left of the scale 10, the contact arm 62 is normally caused to efiect engagement of switch blade 1I with coutact 12'. A spacer 69 is carried by arm 62 to prevent electrical contact between arms 62 and 14.

A step-down transformer 1s used to supply low voltage power for operation of the system. 'I'his transformer comprises a line voltage primary 11 and a low voltage secondary 18. The line voltage primary 11 is connected by wires 19 and to any suitable source of power (not shown) Operation The various elements of the system are shown in the position which they occupy when the temperature to which the thermostat 60 responds ls above the setting o1! the thermostat. Moreover, the various elements are shown in the shutdown position wherein the pilot burner is extinguished. Let it be assumed now that the temperature falls to the setting 01 the thermostat so as to cause 64 and then engagement of contact arm 63 with contact 65. Upon engagement 012 contact arm 62 with contact'64, the following circuit is established to igniter 24: from the upper terminal of secondary 18 through conductor 82, contact 64, contact arm 62, bimetallic element 6I, conductors 83 and 84, contact 54, contact arm 50, couductor 85, igniter 24, and

conductors

89 and 90 the other terminal of secondary 18. The energization 0f igniter 24 causes the same 120 heat up so as to be ready to ignite the pilot burner upon opening of the pilot burner .valve I9.

A1: the same time as the energlzing circuit is established to igniter 24, a parallel energizing circuit is established to the heating element 36 as follows: from the upper terminal of se'condary 18 through conductor 82, contact 64, contact arm 62, bimetallic element 6I, conductors 83 and 84, contact 54, contact arm 50, conduotor 9I heating element 36 and

conductors

92, 93 94, and 90'to the lower termin al of sepondary 18. The energization of heating element 36 causes it 60 heat the bimetallic element 34 which, upon being heated warps upwardly so that the right band end thereof moves along the inclined portion 46. The upward movement of bimetallic element 34 raises the v a1ve stem 33 of pilot valve I9 upwardly to open tl1e valve. The, opening o! the valve permits gas to flow 120 tho pilot burner which is ignited by the igniter 24 which is now hat. The continued heating of bimetallic element 36 causes it to continue to warp until the right band end thereof passes over the inclined portion 46 on 60 the shoulder 41. As soon as this happens, the spring 48 is able to move contact arm 44 in a.

63 withcontact 65. As is customary, thermostat 75 clockwise dh'ection sufl'lcientlY 1 -68115@ diSengagement of contact arm 50 from contact 54. When contact arm 50 disengages from contact 54, the energizing circuits to both the igniter, 24 and the heating element 36 are interrupted. The bimetallic element is now able to cool off but due As soon as the auxiliary pilot fiame heats the bimetallic element 22 sufiiciently, this element engages contact 23. When this happens the various elements are in the position assumed during normal operation of the system. Withthe ele- -ments in this position let it be assumed now that both contact ums 62 and 63 are in engagement with their respective contacts. When such engagement occurs, the following circuit will be established to the valve winding 29. From the upper terminal of secondary 18 through conductor 82, contact 64, contact arms 62 and 63, contact 65,

conductors

95 and 96, valve solenoid winding 29, conductor [00, contacts 32 and 4I, conductor 91, bimetallic element 22, contact 23 and

comductors

98, 94, and 90 to the other terminal of secon dary 18.

The energization of winding 29 causes upward movemept of the solenoid core 28 to cause opening of the valve and engagement of switch blade 30 with contact 3I. Upon switch blade 30 engaging contact 3I a holding circuit is established for the winding 29 as follows: from the upper terminal of seconclary 10 through conductor 82, contact 64, contact arm 62, bimetallic' element 6I, conductors 83 and 99, contact 3I, switch blade 30, conductor 96, winding 29, conductor I00, cantacts 32 and 4I, conductor 91, bimetallic element; 22, contact 23, and

conductors

98, 94, and 90 to the other terminal of secondary 18. II: will be noted that this new cirt:uit is independent. of cantact 65 so that the circuit 1:0 the valve winding is not interrupted until contact arm 62 has separated from contact 64. Thus the valve winding 29 is not initially energized until both conta'cts being br0ught into operation. Upon the arm 66 being so moved, contact arm 62 is moved against the switch blade 1I to force the Same into en'- gagement with contacb 12. As pointed out previously, the insulating spacer 69 prevents any electrical contact being established between cout-act arm 62 and switch blade 1I. As soon as switch blade 1I is moved into engagemnt with contact 12 an energizing circuit is established 130 the heating element 56 as follows: from the upper terminal of secondary 18 through conductors 82 and I 0I, switch blade 1I, contact 12, conductor I02,

contacts

40 and 39, conductor I03 heating clement 56, and conductors I 04, 93, 94, and 90 to the other tezminal of secondary winding 18. The establishment of this circuit to heating element 56 causes the same 1:0 heat the bimetallic element 52, causing the latter to warp downwardly and rock arm 51 in a counter-clockwise direction. When the arm 5I is so rocked, shdulder 41 is moved out from undemeath the bimetallic element 34 permitting the element 34 to spring to its cold position in which it is shown in the drawing The valve I9 is now completely clos ed so that the pilot; burner is extinguished. When the element 34 moves downwardly to its cold position,

contacts

39 and 40 are separated so as to interrupt the energizing circuit I:o heater 56. This heater now cools 01T a1loWing the bimetallic element 52 to cool oft and retum to the position shown.

As soon as bimetallic element 34 leaves the shoulder' 41, contacts 32 and4l are separated. This interrupts the circuit to the valve winding 29 and prevents reopening of the va1ve I4 until the system has completely recycled. Ifit Were not for contacts 32 and4l, the valve I4 could be opened immediately afber the closure of pilot burner valve I9 and before bimetal 22 separated from contact 23 by movement of adjusting arm 66 to cause reengagement of contact arms 62 and 63 with contacts 64 and 65. This would result in gas being admitted to the maih-burner with 64 and 65 have been engaged and iI; is not deenergized until both of these contacts have been disengaged. In this manner a diiferential between the energization and deenergization of valva winding 29 is proi1ided so as to eliminate any danger of chattering operation When the thermostat first makes or breaks its contacts.

The energization of valve winding 29 With the resultant opening of valve I4 admits gas 1:0 the burner I0 which gas is ignited by the pilot burner I1. Under normal operation of the system, the burner continues in operation until both contacts 64 and 65 have been disengaged to cause closure of valve I4. Such closure does not however affect thgoperation of the pilot burner which coutinues in operation so as to be ready to light the main burner upon the next ca1l for heat by the accidently extinguished, the main valve cannot be opened since bimetal 22 separates from the contact; 23.

Let II; be assumed now that because of the outside temperature being warm, the householder desires for the system to be shut down. All that iI; is necessary to do is to move the contact arm 66 to the lowermost position on scale 10. This is more or less a natural operation since this is the conventional way of preventing thebumer from 75 adjacent the thermostat 60 thermostat 60.- If at any time the pilot burner is no means to immediately reignite it. With the provision of contacts 32 and '4I, this possibility is eliminated.

Upon the householdor desiring to put this System into operation again, the adjusting arm 66 need merely be moved to the desired temperature setting and as soon as the thermostat calls for he at the system will be again placed in operation. It is to be noted in this connection that the heating element 36 and igniter 24 are energized when only contact arm 62 engages contact 64 so that by the time that contact arm 63 has engaged contact arm 65 to cal1 for valve operation this system will normally be in condition I;o permit immediate opening of valve 29. In other words, during a normal slow temperature fall the timg between the engagement of contact arm 62 and contact 64 on the one band, and contact arm 63 and contact 65 on the ot her band, is sufficiently long to permit the opening of pilot valve I9, the ignition thereof and the heating of bimetal 22.

While the apparatus hasbe6n shown in some what detailed form for purposes of illustration, it is I:o be understood that the units including I;he bimetal elements 52 and 34, their respectiv e heaters, and the hell crank 42 would inactual practice be housed in a relatively small -casing associated with the pi lot valve I9. II; is furthermore to be understood that where desired the switchblade 1I and contact but not associated 12 may be merely' appended claims.

' tremely simple and efiective system for insuring dependable normal operation of a gas burner with means for conveniently shutting down and reigniting the pilot burner when desired. With the present System the. householder need never approach the vicinity of a gas burner and a.t the same time will not need to wait; for a service man from the gas company to relight; or turn ofi bis pilot burner.

I have shown a specific embodiment f my invention, it is to be understood that this is for purposes of illustration only and that the inven tionis to be limited only by the scope of the I cl aim as my invention:

1. In combination, a main burner, a main valve said pilot burner valve, and means operative upon said valve being so closed anti upon said condition responsive device calling for burner operation to open said pilot burner valve and cause ignition 01 said pilot burner.

2. In combination, a main burner, a main valve controlling the flow of fuel thereto, a. normally constantly burning pilot burner, a pilot burner valve controlling the flow of fuel t ;hereto igniting means for said pilot; burner, means including a device responsive to a controlling condition for controlling the operation 0f said main valve means located adjacent said condition responsive device for causing closure of said pilot burner valve, am]. means operative upon said valve being so closed and upon said condition responsive device calling for burner operation to Open said pilot burner valve, render seid ignition means operative to ignite said pilot burner, and later render said ignition means inoperative.

3. In coinbination, a main burner, a mein valve controlling the flow of fuel thereto, a, normaliy constant-ly burning pi1ot burner, a pilot burner valve controlling the flow of fuel thereto, means including a remotely locatea device responsive to a controlling condition for controlling the operation of said mein valve, means for maintaining said pilot burner valve open and seid mein va1ve under control of seid device, means including a control device located remotely' -from seid 'burners for rendering said previously named means imperative thereby to cause closure 015 seid pilot burner valve, and means including a. c0ntrol device associ.ted with and movable with said pilot burner valve for causing an immedlate closure of seid mein valve upon closure of seid pilot burner valve.

4. In combination, 'a main burner a mein valve controlling the flow 015 fuel thereto, a normally' c onstantly burning pilot; burner, a pilot burner valve controlling the flow of fuel thereto, means including a remotely located device responsive to a. eontrolling condition for controlling the operation cf seid main valve, means for maintaining seid pilot burner valveopen and said mein valve under .control of said device, and means including a control device loca.ted adjacent said condition responsive device for rendering said previously named means imperative thereby to cause closure of said pilot burner valve.

5. In combination, a main burner, a mein valve controlling the flow 01 fuel therato a normally constantly burning pilot burner, a. pilot burner valve controlling the flow of fuel thereto, means including a remotely 1o cated device responsive to a controlllng condition for controlling the operation of seid. mein valve, means f or adjustin the eondition setting o! said condition responsive means, means for maintaining seid pilot burner valve open continuously am: means including a control device associated with said adjusting means for rendering seid previously named means imperative thereby to cause closure-o1 said valve.

6. In combination, a main burner, a main valve controlling the flow of fuel thereto, a. normally constantly burning pilot burner, a pilot burner valve controlling the flow of fuel thereto, means including a remotely located device responsive to a controlling condition for controlling the operation of seid main valve, a latch for maintaining said pilot burner valve open,-

electrically operated means for releasing seid latch, and means including a control switch 10- cated adjacent sa'id condition responsive device for energizing said electrically operated means and releasing seid latch.

7. In combination, a main burner, amain valve controlling the flow of fuel thereto, a normally constantly burning pilot burner, a. pilot burner valve controlling the flow cf fuel thereto, means including a remotely located device responsive to a controlling condition for controlling the operation 012 seid mein valve, a latch for mairitaining seid pi1ot burner va1ve open, an electrothermal motor for releasing said latch, and a. switch adjacent seid condition responsive device for controlling the energization cf seid electrothermal motor.

8. In combination, a main burner, a. main 'valve controlling the flow of fuel thereto, a normally constantly burning pilot burner, a pilot burner valve controlling the flow of fuel thereto, means including a remotely located device responsive to a controlling condition for control- 1ing the operation of said main valve, a latch for maintaining seid pilot burner va1ve open, electrically operated means forreleasing seid latch, and a. pair of switches in series for coutrolling the energization of seid electrically operated means, one of seid switches being located adjacent said condition responsive device and -said thermostat, means for holding seid pilot burner valve open, a.nd means including a. coutrol device associated with seid adjusting means operative upon seid, .djusting means being.

moved to its lowest setting to render said holding means imperative and thereby ca.use closure o1! seid pilot burner valve.

10. In combination, a. main burner, a main valve controlling the flow of fuel thereizo, a. normally constantly burning pi1ot burner a pilot burner valve controlling the flow of fuel thereto, means for holding said pilotburnervalve open,

igniting meens for seid pilot burner. meens tor opening seid pi1ot burner velve, meeins ineluding e rem'otely loceted device responsive 1:0 e controlling condition for controlling the operation cf seid mein velve, meens including a cantrol device loeeted edjecent seid condition responsive device for rendering seid pi1ot velve holding meens imperative thereby to euse closureof seid velve, endmeens rende1ed operative upon closure of seid velve to render seid ignition meens end seid velve opening meens operative upon e. cell for burner operetion by seid condition responsive device. 11. In combinetion, e mein burner, e mein velve controlling the flow of fuel thereto, e norme1ly-constently burning pilot burner, e pilot burner velve eontrolling the flow of fuel thereto, e mechenicel letch for meinteining the pilot burner velve open continuously, meens ior releesing seid letch to ceuse closure of seid pi1ot burner velve, meensincluding e device responsive to the tempereture et the pilot burner fleme for ceusing closure of seid mein burner velve upon cooling of seid tempereture -responsive device due to extinguishment of seid pi1ot burner, end further meens responsive i;o the position of seid pi1ot burner velve for ceusing immediete closure of seid mein burner velve upon closure of seid pilot burner velve.

12. In combinetion, e mein burner, e mein velve controlling the flow of tue] thereto, e pilot burner, e pi1ot burner velve controlling the flow 01 fue1 thereto, meens including e remotely loceted deviceresponsive to e. condition indicetive of the need for operetion 'of seid mein burner for controlling seid meinvalve, e. control member opereble between e first position in which it holds seid pilot burner velve open end simulteiieously ceuses seid mein velve to operete under control of seid device, end e second position in which 'it ceuses closure o! both seid velves. end meens including e switch loceted edjec'ent seid device for controlling the position of seid member.

' 13. In combinetion, e mein burner, e mein velve controlling the flow 01 fuel thereto, e pilot burner, e pilot burner velve controlling the flow of fuel thereto, meens for controlling seid mein velve including e. remotely loceted device responof seid device, end e second position in which it c1oses seid pilot b1irner velve end opens seid switch to ceuse closure of seid mein velve, end

meens including e. switch loceted edjec'ent seid device for controlling the position of seid memher.

14. In combinetion, e mein burner, e mein velve controlling the flow of fuel thereto, e normelly constently burning pilot burner, e. pi1ot burner velve controlling the flow of fuel thereto. meens including e remotely' loceted thermostet ior controlling the operetion of seid mein velve,

meens for edjusting the tempereture setting of seid thermostet, meens for holding seid pilot burner velve open, meens including e control device essocietedwith seid edju5ting meens operative upon seid edjusting meens being moved to its lowest setting to render seid holding meens inoperetive end thereby ceuseclosure of seid pilot burner velve, end meens responsive to e cell for heet irom seid thermostet for opening seid pi1ot velve end igniting the fue1 flowing from seid pilot burner.

- 15. In combinetion, e mein burner, e mein velve controlling the flow ot fuel thereto, e normally constently burning pilot burner, e pilot burner velve controlling the flow of fue1 thereto,

meens including e remotely loceted thermostet forcont;rolling the operation of seid mein velve, meens for edjusting the tempereture setting 015 seid thermostet, meens fo17 holding seid pilot burner velve open, meens including e control device essocieted with seid edjusting meens operetive upon seid edjusting meens being moved to its 1owes't setting 120 render seid holdingmeens imperative end thereby eeuse closure oi seid pilot burner velve, meens essocieted with seid pilot velve for preventing opening oi the mein velve unless the pilot velve is open, end meens responsive to e call tor heet from seid thermosive to a condition indicetive o! the need 101 stet for opening seid pilotvelve end igniting the fuel flowing from seid pilot burner.

ARNOLD E. PE'IERSEN.