US2296025A

US2296025A - Ignition and control means for fuel burners

Info

Publication number: US2296025A
Application number: US281549A
Authority: US
Inventors: John C English
Original assignee: JOHNSON GAS APPLIANCE Co
Current assignee: JOHNSON GAS APPLIANCE Co
Priority date: 1939-06-28
Filing date: 1939-06-28
Publication date: 1942-09-15
Anticipated expiration: 1959-09-15

Description

Sept. l5, 1942. J. c. ENGLISH- -2,296,025 Y IGNITION AND coNTRoLMEANs Fon FUEL BURNERS `Filecl June 28. 1939 n. @mmf `@n.5 .m/ @n m AN Y maV m. 1 Q Q l M I A? m.\ n `w\ \bM./\ C N @i M mw #Sm `M `M l W` .m-\ M" hmf.

" like. l, l

lOther ignition systemsehave been proposed `mainburner.` QAnother mportantobject of" my invention is n Patented 115,' 15942V l i uNITI-2D STATES PATENT OFFICE i" 2,296,025 ,I m `f IGNITION'ANn 'CONTROL MEANS Foa FUEL BURNERS l John Cf English, Cedar Rapids, Iowa, assigner to `Johnson Gas Appliance Company, Cedar Rap- Y ids, Iowa, aY corporation of Delaware Application June 28,1939, serial No. 281,549V

2 claims. lol'. V15s-117.1)

This invention relatesto fluid fuel burners and 2e has particular relation toan ignitionand control means forsuch burners.

It is\the usual practice in many types of gas heating devices adapted for intermittent useto utilize a constant burningpilot light forfi'gnitirg the gas issuing from the main burner. However there are numerous diihculties `with'this ignition system, among which are" the cost of the system ma located outside the burner chainber. Another in electrical ignitlng devices.

`Another object of my invention is to provide an ignition and control system which is ln operative unless there is suiicient gaf. Pressure to opdevices, asfor instance lighting the pilot burner in the fall and turning it out in thesprina;V as? well as lighting it in theevent ofA the pilot light `going out.,` j Also the pilot light is not altogether reliable since only a small amount of gas is used and the pilot light may go out. Also fouling ofthe light may occur to cause diagreeable odorsand the utilizing electricity for ignition purposes, but

f Ihese Systems have not been altogether satisfactoryfor the reason `that the `switchesr'nay stick or they may be located inthe heatv zone and corroding of the contacts-'mayoccur. Manual ignition may be employedof course, butthis entails danger by reason of explosion, asphyxiation and the like, as well as lower efllciency by reason ofthe doors or thelikevnecessary for manual ig,

,nitio'n.` e

' vIn othertypes'of heating systemsvalves are employed for controlling the flow of fuel, but it i'sjpractically impossible to connect up any sort of electrical system Ato these valves to thereby profor gas burners and the like whichshall overa tioned'and which willeliminate the necessity for erate the main burner.

Another object of my invention is to provide means for igniting a gas burner or the like with` out the necessity `of using doors or other apertures to furnish a means of reaching the burner 'from outside` the heating device.

panying drawing alnd following specifications, fwherein is disclosed a single exemplary embodiment of the invention, with the understanding, however, that such changes may be made therein as fall within `the scope `of the appended claims, without departing from the spirit of the invention.

, ,burner, and Y Figure 2 is a schematic drawing showinga- Figure 1 of the drawing is a schematicdiagram illustrating one embodiment of my invention and how it may be used in connection with a gas modified form ofthe switch shown in Figure l` Referring ,now to the drawing: The device there shown is particularly suitable for use with gas burners but quite obviously may be modified for other burners and other purposes.

Y The main portion of thecontrol' means is preferably located within the oven or other burner chamber `adjacent thejburner. This main pormanual lighting or alconstan't burning pilot light.

It .i'sanother objectofmy inventionto provide ignitionlandcontrol means for automatically lighting` a fluid fuel burner without Idanger of explosion or injury to the operator, which means shall be :"fool proof.a`nd in which the faifnreI cf any of the parts ofthe mechanism to function` resrltsonly in stopping the series of operations leading to ignition of thegasissuing from `the to provide aquick acting ignition and control `means'infwhichheat `sensitive portions'of thetion includes a body I0, more orless rectangular in form. The body I0 hasa supply inlet in the lower face thereof indicated at I .V This supply line can of course be brought in from the side as well as the bottom of the block-like base I0.

The inlet Ii leads into acylindrical chamber I2.

. Concentricwith the outerl chamber I 2, is a smaller inner chamber I3. The wall of the channel between the chambers I2 and I3 is beveled, as indicated at I4, to form a valve seat for a valve The valve is normally seated against the objecty of my invention is to very materially reduce the amount of wiring required t al* ythe linefconnectlon 43.

` mercury switch 31.

The central has a notch I9 therein for the purpose of receiving the free end of a bi-metal strip as hereinafter explained.-

A U-shaped bi-metallic member 2l is secured to one end wall of the 'base member I0 by means of the bolt 22, and the free end of the U-shaped bi-metallic member is received within the notch I8 `of the member I8, as indicated at 23. It is apparent that .differential expansion and contraction of the two layersv of dissimilar metals, which constitute the structure of the bi-metallic strip, will cause reciprocation vof I to raise and lower the valve I4. The bi-metallic strip is so constructed and arranged that heating of the loop of' the strip, as by means of the flame issuing from a pilot burner 24, will cause contraction of the loop to drive the stem inwardly to raise the valve I6 from its seat. When this is done the gasv admittedat the inlet or supply II passes through the chamber I2, into the chamber I3, out through the outlet 26, through the conduit 21, and out fthroughthe main burner 28.

Ignition for the pilot burner 24 by means including l trode 3l is supported by means of a'bracket 82 fromthe'base I0. l sulated from the-bracket. Current for causing i va high voltage discharge through the gap 38 is furnished by means of the step-up transforman electrode 3|. elec- The electrode is of course inerA 34.

The primary of the step-up transformer 34 is terminal 36 to the'body i .or casing of a mercury switch indicated generally y at 31. A connection is thus made between the grounded by means of the terminal 36 and a pool of electrically conductive liquid, such as mercury, indicated at 38. An al ternative arrangement, indicated by the dotted.

. lines, `inl the event that a non-metallic switch 'l "casing is employed,

is to directly connect vthe the valve stem y l I6 fron its'seat y,

is furnishedby means of a chamber I3.

Now itis apparent that when the gas is on to supply gas to the burner 28it will first pass into the chamber I2, and from this chamber second conduit 62 with the inner will pass upwardly to the pilot burner orifice 54 .and out throughl the slot 58 of the pilot burner.

Gas will also pass through the conduit 48 into .the chamberVK 44. AInasmuch as this gas is at higher than atmospheric pressure, the mercury within the chamber 44 and outsidethe tube 41 '.will be depressed to drive mercury up within the tube 41.'

The mercury within the tube 41, when it reaches a suiliciently high level, contacts with the'lowe'r endof the electrode 45 and closes'the circuit through the primary of the ignition trans- .former- 34.y The high voltage of the secondary winding causes an are across the gap 38 to the grounded electrode 30 on the body I0 to ignite y the gas issuing. from thepilot burner 21.

`Theburning gas vfrom the pilot burner heats the bi-metallic element 2 I which raises the valve I6 from its seattolpermitggas' to flow into the chamber ,I3 and the main burner.. Assoon as I thisA yoccurs the pressure the chambers I2 and, I3 is equalizedand consequently the pressure within the chambers 44 and 46 of the switch -is also equalized, which permits the'mercury 88 v .to seek, its own levelandthus break the contact between. the electrode v and `the mercury 38. Breaking 'of theprimary circuity of-coil 34 stops the discharge.- of electricity across the gap533.

i; Itis apparent that gas is not admitted'to the main burner until the pilot `burner is ignited.

` Ignition of. the pilot yburner occurs only when gas isfadmittedtc the suppiyinlet il. Assoon as the supplyoffgasvisl cut o, the burning Aof gas Yprimary of the transformer to an electrode 38 Y I extending into the mercury pool. i The other side of the primary coil is connected I to the secondary 4I of a step-down power transfurnished by means of The other side of the secondary coil `4I of the power transformer is connected to the central electrode 45 of the. This central electrode 45 is, conditions, spaced above the mer- `former 42, power being under normal cury pool 88 so that no electrical contact therewith is made.

. .There are two chambers 44 and 46 within the switch casing 31. The upper chamber communicates with the lower by means of a tube 41 which atthe main burnerand at the pilotburner ceases and the thermostat 2| cools to close the valve Iii.l As-soon asthe. valve is closed, gas cannot be admitted to the ,main burner unless the pilot i burner is ignited. i

My inveritirmV is susceptible to numerous modirlcationsyI mayutilize only one transformer and rpass .a .-110 `volt circuit through the mercury switch 31, ror may eliminate both transformers and pass thecurrent direct through the mercury `switch 31 and electrode 3 I projects down from the upper chamber into theV lower chamber and into the mercury pool 38. electrode 45 projects downwardly rom the insulated cap 50 to a position within this tube.

' l The'lower chamber 44 is connected by meansL f of a conduit 48 Vto a channel 49 Ain the body III.

The mercury switch 31 is located outside of the oven or other enclosure in which the burner is 5Iy of the enclosure; The conduit or within the base I0 communicates with the chamber `I2 and is also connected with the pilot burnpassing through the wall er orifice 54. When gas under pressure is present in the chamber I2,

The upper channel 48y it will pass outwardlyA 'through the restricted orifice 54 and will also setup a pressure in the conduit 48 and the lower chamber 44 of the mercury switch.4

chamber 46 of the mercury switch AlthoughI have described a specific `embodiment of my invention, it is apparent that modifications thereof maybe made by those skilled in the art. Such modicationsmaybe made without tdepartingfrom the spirit and scope of my invention'asset.forthin the appended claims.

Iclaim asmyinvention: v I l. Inafluidr fuel. burnerv adapted .tobe operated in arsubstantially .closed combustion space, a valve having inlet and outlet chambers, a main burnerconnectedwith the y.outlet chamber, a pilot burner. connected directly with the inlet Y ychamber, aY means responsiveto. heat fromv the pilot burner foropening the valve, andswitch means-located outside-the 'combustion space and responsive to differences in fuel pressure ln the inlet andi outlet chambers, -for controlling ignition -o the-pilot burner, said pilot burner being.. -supplied with fuel-from rsaidinlet chamber independent of .said switch means.

2; In afl-fluid Afuel.burner,.a control;l valve having inletv andoutlet ports, a gas supply line connected to the inlet port, a main burnerconnected tothe outlet. port,va. pilot burner thermal control. fmeans; activated by-heat `from the pilot is connected burner for .operatingrlthecontrol valve, electric turned i t e Temeon 1 e `3 ignitio meafns `for `the -pilot burner;` "al difieren#- tial pressure swtcheonnected with the intake port `and. with the outlet port wherebyan vin`-` crease in pressure differential betweenfuel in the intake and AOutlet ports willy close thefswitchY `to energize the `electric ignition means and whereby audecreaselin the pressure diierential will` operi the switch and ie-energize the ignition *l means said pilotburner beingiin direct'communiv cation with said supply line" to `receive Vgas `coriy tnuously therefrom `:its long as gas is"supp1ied to i said `gas `supply line regardless of the `position of said ignition mens;

i I@ClaironNGLISH.