US2591897A - Safety device for fuel burners - Google Patents

Description

V. WEBER ET AL.

SAFETY' DEVICE FOR'FUEL BURNERS April 8, 1952 original Filed April 1, '1944 3 Sheets-Sheet l INVENTORS. Vieron @Tenez Bossu/ 56am/2 April 8, 1952 v. WEBER ET AL SF'ETY DEVICE FOR FUEL BURNERS riginal Filed April 1, 1944 3 Sheets-Sheet 2 E 2m m56@ el.. m a

April 8, 1952 WEBER Er AL SAFETY DEVICE FOR FUEL BURNERS 3 Sheets-Shet 3 Original Filed April 1,- 1944 e. .2% SER a n Y TEG E N mwa R 0 mi /h [0H T. r mm, .w VP M lm Patented Apr. 8, 1952 UNITED STATES PATENT OFFICE SAFETY DEVICE FOR FUEL BURNERS Victor Weber, Greensburg, and Russell F. Garner,

Youngwood, Pa., assignors lto Robertshaw- Fulton, Controls Company,'Youngwood,-P'a., a corporation of Delaware Original application April 1, .1944, `SerialNo. 529,201. Divided and this application. April 21, 1948, Serial No. 22,406

l. This invention relates to safety controls for fuel burners and, more particularly, to thermoelectric devices for controlling flow of gaseousl fuel to water heaters and likeappliances. Appliances of the type indicated havebeen provided'with electrically operated safety valves which areenergized by current generated by a thermo'electric device exposed tothe ameof the pilotburner. The safety valve is thus operable'for shuttingoft the flowof fuel tothe main'and'pilot burners of the appliance when the pilotburner becomes extinguished. Various means have also been provided lto render the thermoelectric device incapable of maintaining the safety valveY open during the normal operationv ofV the burners ifa Vdangerous condition arises, such as excessive temperature or pressure ingthewater being'heatedby the burners.

v An objectof this invention is to improve such devices by providing positive acting means to shut-off the'flow of fuel to the main and pilot burners "whenever apredeterrnined water temperature is'reache'd.

-Anotherobject ofthe invention is to accomplishl the shut-off by operation of the thermoelectric safety valvebut independent of the current generated by the thermocouple.

Another object -of the Yinvention is to insure positive actuation of the safety valve to closed position both in the event of pilot flame' extinguishment or excessive water temperature;

Le claims. (o1. 137-139) Figs.'-12 and 14 are partial sections takenon line XII- XII of Fig. 3 showing the different port positions of the main control valve; andi Figs. 13 and 15 are partial sections taken on line XIII-XIII of Fig. 3 showing the different by-pass passage positions of the main control valve.V I

` Referringmore particularly to Fig. lrof the drawings, the main burner I0 of a water heater I2 is supplied with gaseousfuel through a'pipe I4 and the pilot burner I6 for the main burner Vis f scribed hereinafter.

Another object of the vinvention is-to prevent uflow of fuel to the main burner until the pilot burner produces a name. y

kOther objects and advantages will become apparentA from the followingdescription takenk in connection with .thev accompanying drawings, wherein I ;Fig.`1is a schematic view `of a-.waterheater having lthesafety control of this inventionapplied thereto; f p .i Fig. 2 is a plan View of the safety control;

Fig. 3 is a section taken on the line III-III of Fig. 2;` Fig. 3a is. a partial section taken on the line IIIe-Illa of Fig. 2; f Fig. "4 lis a section taken on .the line IV--IV of Fig; 2; Y

Figi 5 is a partial section taken on the line V--V Figs; 6to 10 inclusive are plan and elevational views of detailsof af lever supplied with-gaseous fuel through a'pipe I8, The fuel supplied to both the main and pilot burners is controlled by the control device 2| of this invention and which will be more fully de- The pilot burner I6 pro# duces a flame which serves to heat a thermocoupler element 20 Apositioned adjacent thereto and upon extinguishment of the pilot burner flame the thermocouple` 2li will cool and cause the gas supply to the main burnerl I0 to be cut off by operation of the control device 2| of this invention.

Referring now more particularly to Figs.- 2, J3 and 4 ofthe drawings, thecontrol device 2| of this invention comprises a housing formed of two main parts, namely, a valve body 24 and a magnet body 26. These parts are suitably bolted' or otherwise secured together and sealed against leakage of gaseous fuel through the joints thus formed.

The valve body 24 is adapted for. insertion in the pipe I4 by provision of an inlet 28 at one end thereof and an outlet 30 at the opposite end thereof to which the pipe I4 may be threadedly connected. Between the inlet 28v and the outlet 30 is a valve seat 32 with which a valve member 34 is adapted` to cooperate to controlow of fuel from the inlet 28 Ato the outlet 30. The valve member 34 is reciprocable toward and away from the seatV 32 by a stem 36 supported in the valve body 24 and is biased away from the seat 32-by a coil spring 38 extending between'the body 24 and the valve member 34. Y

The valve stem 36 projects through the valve member 34 into a valve chamber 4I] formed in the valve body 24 in communication with the inlet 28 and providing an opening 42 in the valve body which is closed by the magnet bodyy 26..

v The valve body 24 is also provided with a tapered valve seat 44 extending transversely ofthe inlet 28 and in which a tapered plug valve mein- ,ber 46 ismounted for rotation.` .The plug Valve 46 is provicledwith` a port'48 extending transversely therethrough, and which may be moved into alignment with the inlet 28 for passage of fuel to the valve chamber 48. A dial 58 carrying the indicia on, Pilot and off is secured to a stem projecting from the larger end of the plug valve 46 exterior of the valve body 24 and provides manual means for rotating the plug valve 46 in the valve body to selected positions.

The larger end of the plug valve 46 is provided with an arcuate groove 52 formed in its surface and serving in selected positions of the valve to connect the opposite ends of a by-pass passage 54 formed in the valve body and which the tapered Vvalve seat 44 intersects. One end of the by-pass passage 54 communicates with the inlet 28 and the opposite end communicates with a passage 56 leading to a pilot valve stem chamber 58 (Fig. 4) extending axially in a boss 59 on the magnet body 26 and communicating at one end with the main valve chamber 48. Reciprocably mounted in the valve chamber 58 is a valve stem 68 provided with longitudinal recesses for passage of fuel from the valve stem chamber 58 into an enlarged pilot valve chamber 62 which overlies the chamber 58 and connects therewith. The valve stem 68 has an end projecting into the main valve chamber 48 and serving to support a. sealing device 63 to prevent fuel ow between the main valve chamber 48 and the chamber 58. Passage of fuel between the valve stem chamber 58 and the-valve chamber 62 is controlled by a pilot valve member 64 secured to the valve stem 68 and movable into and out of engagement with a valve seat 66 formed on the shoulder intermediate the chambers 68 and 82.

The pilot valve member 64 is biased into engagement with its seat 66 by a coil spring 68 extending between the valve member 64 and a cap 18 which forms a closure for the chamber 62. Communicating with the chamber 62 is a passage 12 formed in the magnet body 26 and leading to a connection 14 for the fuel supply pipe |8 of the pilot burner I8. A suitably a-pertured adjusting member 16 for the pilot burner fuel supply may be mounted for manual rotation in a boss 11 formed on the magnet body 26 and having an axial opening intersecting the passage 12. Adjustment of the member 16 which projects exteriorly of the magnet body serves to vary the orifice size of the passage 12.

As hereinbefore indicated, the valve mechanism Vof the present invention is provided with an arrangement for causing both the control valve 34 and the pilot burner valve 64 to move to closed position upon extinguishment of the pilot burner I6. This mechanism is mounted in the magnet housing 26 which is provided with an enlarged recess 18 opposite the opening 42 of the valve chamber 48. A magnet 88 is secured in the recess 18 and is of the horseshoe type having the usual coils 82 positioned on each leg thereof and connected to receive electric current generated by the thermocouple 28. The thermocouple 28 may comprise the usual pair of elements of -diiferent thermoelectric properties which are joined at one end to form a hot junction exposed to the iiame of the pilot burner |8.

f In the embodiment illustrated in Fig. 4 the thermocouple 28 is of the tubular type but it will tween the armature 84 and the bottom of the magnet 88. The coil spring 88 is stronger than the spring 38 for the valve member 34 and acts in opposition thereto for seating the valve member 34 as will be apparent hereinafter.

The end of the stem 86 projecting on the opposite side of the armature 84 threadedly engages with-a cap nut 98 which is located in valve chamber 48 in proximate relation to the projecting end of the valve stem 38 with which it is axially aligned. The cap nut 98 may be guided in an apertured retainer plate 92 which serves as a closure for the open end of the enlarged recess 18 and also serves to secure a sealing gasket 94 across the open end to prevent passage of fuel from the valve chamber 48 into the magnet bod5`r 26.

As the voltage generated by the thermocouple 28 is relatively small, the spring 88 Will serve to maintain the armature 84 in its released position, as shown in Fig. 3, even if the magnet is in energized condition. As is customary in such devices, means are provided for resetting the armature 84 against the pole faces of the magnet 88 by a manual operation owing to the lack of sufi'lcient magnetizing force to attract it from released position. To this end, a reset stem 96 is mounted for reciprocation in a reset stem chamber 91 formed in the magnet body 26 on one side of the magnet 88. The reset stem 96 carries a nut 98 projecting on the exterior of the magnet body 26 and is urged outwardly from the chamber 91 by a coil spring |88. The outward movement of the stem is limited by a collar |82 on the reset stem 98 Which engages with a flanged portion |83 of the magnet body 26 forming a guide for the stem 96. Beyond the collar |82 the reset stem projects through an aperture into the valve chamber 48 for the purpose of effecting actuation be understood that any other arrangement which which projects on either side thereof and sup- H ports on one side a coil spring 88 extending beof means for resetting the armature 84 as described and also to maintain the control valve 34 seated during the resetting operation.

The means for accomplishing this dual function includes a channel-shaped plate |84, shown in detail in Fig. 6, which has its base secured to the magnet body 26 with the opposite sides thereof projecting into the valve chamber 48. A pair of spaced slots |86, |88 are formed in each of the sides of the channel-shaped member |84 and a perforation ||8 is provided in the base thereof through which the projecting end of the reset stem 96 may extend. An operating lever ||2, shown in detail in Figs. 8 and 8a, is pivoted intermediate its ends in the slot |88 and is provided with a raised portion ||4 at one end which engages with the cap nut 98 on the end of the armature stem 86. The operating lever ||2 is further provided with an elongated opening ||6 Within which a connecting lever ||8, illustrated in Fig. 9 of the drawings, is adapted to extend.

The connecting lever I8 has a forked end |28 which extends on both sides of the operating lever ||2 at one end |2| thereof, this end being suitably bent from the plane of the lever to facili- '-f tate such engagement. A slot |22 is formed transversely in the end of the connecting lever |18 opposite the forked end |28 and is adapted to receive an upturned portion |24 formed intermediate the ends of a holding lever |26 illustrated in Fig. l0 of the drawings. One end of the holding lever |26 is pivoted inthe slots |88 of the channel-,shaped member |84 andthis end is also provided with van opening |28 for the reception of the forked end |28 and the associated Vlustratedin Figs. 12 and 13.

' connecting lever `I |8.

., end |2|- of .the connecting. and operating levers, respectively.

*When the lever mechanism described ispositioned in the valve lchamber 40 the end of the holding lever |26 opposite its pivot extends along the underside of the operating lever |2 and into operative `engagementwith the projecting end of the-control valve stem 36. Extending laterally of lthe raised portion ||4 on the operating lever I I2 is an arm |30 having an upturned end |32 `which is adaptedjto engage with the projecting end of the `pilot valve stern 60 as illustrated in Fig. 4 of the drawings.

In addition to the features of the safetycontrol'sofar described.- the embodiment of the present invention includes an arrangement for causing'closure of thecontrol valve 34 and the pilot burner valve 64 when the temperature of the water in the Water heater I2 becomes excessive. This `,arrangement includes'meansV by Which it is possible Yto move the armature 84to its released position and cause closure of the safety control valve` V34 independently of the current being generated by the thermocouple 20. To this end,` the magnet body 26 is provided with a cover |34 within'which an expansible and contractible element |36 of a thermally responsive device is mounted. Expansion and contraction of the element |36 may be made responsive tothe temperature in the'water heater |2'by the provision of a capillarytube' |38 connected at one end to the element |36 and at the other end to a bulb |40 immersed in the water being heated. The bulb |40, Ycapillary tube |38 and element |36 may be completelylled with a fluid which `remains liquid diateitsends in the 4slot |06 of the-channelrshaped member |04, the opposite end ofthis operating lever will move upwardly causing the raised portion ||4 engaging `the cap nut VSII- to at elevated temperatures such as chlorinated dil phenyl.

y"As `shownvmore clearlyin Fig. 3a., the element |36 is carried on a stud Y|39 supported from an arm mounted on the upper end of the magnet vbody 26. The element |36 is thus free to expand and contractas described and such movements Willserve to reciprocate a pin |42 projecting from the element |36 at the side opposite the stud |39. The pin |42 projects through an aperture in the upper end of the magnet body 26 and through an the pole faces of the magnet 80. In this condition" ofthe armature 84 the spring 88 isv compressed. When the armature 84 is in its released position the spring 88 `is extended and the. stem 86 is spaced fromthe end of the pin |42.

In the operation of the device the dial is first rotated from theol position to the Pilot po-` movethearmature 84 toward thejpole'facesof the magnet 80. 'At the same time, the extended arm .|30 of the operating lever IIZ-will also move upwardly causing engagement between the vup turned end '|32 thereon with the projectingend ofthe .pilot valve stem |50.` Thus, when the armature 84 is inthe attracted position in engagement with` the pole facesof the magnet 80, thepilot control valve 64 is movedoff its seat against 'the biasof .the spring 68. Fuel may `then flow past the pilot control valve |i4and` from the chamber 62 whichv it controls tov the `passage '|2xancl to. the pilot connection 14 and pipe |8 to the pilot burner I6 at an amount controlled byv the adjustment-of the pilot adjustment member'l. The-pilotburner may then be lighted and the flame therefrom will impinge upon the end of the-thermocouple 20 which is connected with. the coi1s`82 of the magnet 80.

During this resetting operation, the connecting lever I8 pivots around the upturned portion |24 .of theholding lever |26 as a fulcrum. :The holding lever |26 is thus held stationaryagainst the projecting portion of: the control valve stem 36-while the raised portion ||4 of the operating lever ||2 moves away therefrom inV engagement with the cap nut 60. Thezcontrol valve-34 is thus held Vlirmlyagainst its seat' 32 .against the biasoi.I its spring` 38 to prevent fuel flow to the main burner should the plug valve 46 be positioned with its port 48 aligned with `the inlet. 28.

' In ash-ort time the thermocouple 20 generates sufficient current lto energize the `magnet and maintain the armature 84 in its attracted posi tion against the pole faces 0f the magnet. The reset button -98 may then be released causing-retraction of thestem 96under the bias of spring |00. The consequent release of pressure on `the sition. 4The position of the plug valve port'48v and by-pass groove 52 in the 01T positio'n is il- Until the Pilot position is reached no fuel can pass the plug valve '46 and both the pilot andmain burner control valves are in closed position. In the Pilot position the fuelmay flow from the inlet 28 by way Vof the arcuate groove 52 to the pilot passage'54 to .the pilot valve stem chamber 58. "The reset button 98 is then manually actuated to depress move the forked end |26 of the connecting lever |I8doWnwardly carrying with it the associated en d| 2| of the operating lever` 2. f thev operating lever ||2 is pivoted interme-l holding lever |26'permits the control valve spring 36 `to move the control valve 34 to openposition carrying `with it the holdinglever- |26 whichis pivoted in the slots |08 of the channel-shaped support 4|04.V The dial 50 maythen be rotatedtto the "onfpositionshown in Figs. 14 and l5 permittingfuel to flow fromthe pipe I4throughthe inlet: 28 to the Valve chamber y 40 andlpast the valve seat 32 to theoutlet 36-connected with pipe I4tothe mainburnerl. In this position ofithe plug valve T46 it will be'observed thatthe arcuate groove 52 permits fuel to ilow to thepilot burner through the same passages as in the Pilot` position. As thespring' 38-of themain control valve V34 isstronger than the spring 68 of Athepilotcontrol valvethe operating and holding levers` are maintained in raised position and the pilot valve 64 is held open during normal running of the burner.' y Y. l v V Inpthe eventv that the pilot' burner is extinguished, the thermocouple ceases to generate current causing deenergization of the electro- VmagnetfV Movement of the armature 84away from the polepfaces of ,the magnet will then occur. Such movement of` the armaturey 874 is caused bythe A springV 88-vwhich'beingi stronger 4thanthe spring 38 of the control valve `3'4gxnoves the safety mechanism operates to close both the 'main' control valve arid-the' `pilot fc'ontro'lval've giving acomplete shut-off of fuel to both main and pilot burners.

If the burner continues to operate without extinguishment of the pilot burner I6 and consequent operation of the safety control described, an vexcessive temperature may occur in the water being heated in the water heater I2. Upon occurrence of this condition, the thermal element |36 will undergo an expanding action and move the pin |42 connected thereto toward the armature stem 86. As the pin |42 is in engagement with. the stem 86 in the attracted position of the armature, the magnetic force tending to hold the armature against the pole faces of the magnet is overcome and the spring 88 will move the armature 84 to its released position. 'I'his `action of the thermal element |36 in overcoming the magnetic force between the magnet 80 and its armature 84 is thus entirely independent of the current generated by the thermocouple 20. It will be apparent that this positive release of the armature 84 and consequent closure of the control valve 34 and pilot valve 64 may occur under conditions of excessive temperature in the water heater even though the pilot flame has not been extinguished and thermoelectric current is still being generated. i In'the embodiment shown in Fig. 1l a modified form of resetting device is disclosed. As the other elements of the construction are identical in all respects with those previously described, similar reference numerals have been applied to the corresponding parts. In this embodiment, the plug valve 46 is provided with stem |44 movable axially thereof and carrying the` dial 56. The vstem |44 and dial are biased from the valve body 24 by a coil spring |46 extending between the underside of the dial 50 and a cover |48 which limits axial movement of the valve stem |44.

The reset stem |50 of this embodiment is located intermediate the plug valve 46 and the magnet 80 and is mounted in a chamber |5| formed in the magnet body 26. As in the previously described embodiment, a coil spring |52 serves to urge the reset stem |50 outwardly from the magnet body but the reset button of the previous embodiment is ldispensed with. In place thereof an actuating arm |54 is mounted on the reset stem |56 exterior of the magnet body 26 and projects into position to be engaged by the dial 50 upon axial movement thereof. The opposite end of the reset stem |50 projects into the valve chamber v40 and is formed with a cupshaped end l56 which is preferably rectangular in cross-section. A pin extends transversely through the rectangular end |56 and through downturned ears formed on a rocker |58 which takes the place of the connecting lever of the previous embodiment. The rocker |58 pivots on the pin* and is provided with a depending end |60 and an opposite depending end |62. A coil spring |64 extends between depending end |62v and the end |56 of the reset stem. A projection |66 on end |62 of the rocker is adapted to engage one end of the operating lever ||2 which may be similar to that .described in the previous embodiment. 'Ihe opposite end |60 of the rocker is, adapted to engage with the holding lever |26 which also may be similar to that described in .the previous embodiment.

The operation of the embodiment shown in Fig. 1l differs from that previously described only inthe resetting operation. In the Pilot position the dial 50 is pushed inwardly toward the valve body '.by a manual operation and serve sntol movethe reset stem |50 downwardly as viewed in Fig. ll. The projection |66 of rocker |58 pivots the operating lever ||2 in support |04 while the depending end |60 restrains movement of holding lever |26. The rocker then pivots on its pin support compressing the spring |64 until the armature 84 is seated against the pole faces of the magnet 80. The pilot burner may then be lighted and the thermocouple will generate sufficient current to retain the armature in attracted position while the dial 50 is released. Movement of the reset stem under bias of spring |52 will relieve the holding pressure of rocker end |60 on holding lever |26 and permit valve spring 38 to open the control valve 34 as in the previous embodiment, rl`he following operations to bring the control into running condition are as previously described in connection with the preferred embodiment.

It will be understood that many changes may be made in the arrangement and combination of parts and in the details of construction herein disclosed within the scope of the appended claims without departing from the invention. This application is a division of our copending application Serial No. 529,201 led April l, 1944, now Patent No. 2,455,542.

We claim:

l. Resetting mechanism comprising an operating lever having a free end, a holding lever positioned on one side of said operating lever and having a free end extending substantially parallel thereto, means for mounting said levers for independent pivotal movement, a connecting lever pivotally mounted at one end on said holding lever and having motion transmitting engagement at the opposite end thereof with said operating lever, biasing means for moving the free end of said holding lever toward said operating lever, second biasing means for moving the free end of s'aid operating lever toward said holding lever, said second biasing means having greater force than said first biasing means, and means operable on said connecting lever for overcoming both said biasing means and causing movement of said free end of said operating lever away from said free end of said holding lever, said second biasing means being effective for returning. said operating lever to initial position and preventing movement of said holding lever when said last means is inoperative.

2. Resetting means as claimed in claim l wherein stop means limit movement of said free end of said holding lever under the force of said second biasing means, and second stop means for limiting movement ofsaid free end of said operating lever upon operation by said last means.

3. Resetting means as claimed l in claim 2 wherein said second stop means include means for overcoming said second biasing means under predetermined conditions, said rst biasing means being thereby rendered effective for causing movement of said free end of said holding lever toward said free end of said operating lever.

4. Resetting mechanism comprising an operating lever pivoted intermediate its ends, a holding lever pivoted at one end and having its free end extending substantially parallel to a free end of said operating lever for independent pivotal movement, a connecting lever pivotally mounted at one end on said holding lever and having motion transmitting engagement at the opposite end thereof with said operating lever, biasing means for moving the free end of said holding lever to- Vward said operating lever, second biasing means 9 for moving the free end of said operating lever toward said holding lever, said second biasing means having greater force than said rst biasing means, and means operable on said connecting lever for overcoming both said biasing means and causing movement of said free end of said operating lever away from said free end of said holding lever, said second biasing means being effective for returning said operating lever to initial position and preventing movement of said 10 second biasing means, and second stop means for 15 limiting movement of said free end of said operating lever upon operation by said last means.

6. Resetting means as claimed in claim 5 wherein said second stop means include means for overcoming said second biasing mans under 20 l0 predetermined conditions, said first biasing means being thereby rendered effective forA causing movement of said free end of said holding lever toward said free end of said operating lever.

VICTOR. WEBER.

RUSSELL F. GARNER.

CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,068 Joesting Apr. 14, 1942 2,245,834 Sparrow June 17, 1941 2,258,811 Ray Oct. 14, 1941 2,309,709 Paille Feb. 2, 1943 2,321,095 MantrI June 8, 1943 2,361,945 Jackson Nov. 7, 1944 2,371,351 Paille Mar. 13, 1945

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