US2461714A

US2461714A - Safety control for gaseous fuel

Info

Publication number: US2461714A
Authority: US
Publication date: 1949-02-15
Anticipated expiration: 1966-02-15

Description

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Patented Feb. 1s, 1949 Paul L. Betz, Baltimore, Md., assignor to Consolidated Gas Electric Light and Power Company of Baltimore, Baltimore, Md., a corporation of Maryland Application May 14, 1946, Serial No. 669,473 8 Claims. (Ci. 236-21) This invention relates to safety controls for burners of gaseous fuels, and has particular utility when applied to such controls for'automatic water heaters and the like. although it is not limited thereto.

In. safety controls of the type referred to it is common practice to use, in addition to a thermostatically operated valve for controlling the ow of fuel to the main burner, a valve for determining fuel ow that is under the control of an electromagnet in a circuit including a generator of thermoelectric current subjected to the heat of a pilot burner, so that upon failure of the pilot for any reason the last referred to valve is closed and discontinuos further flow of fuel.

When it is desired to resetv the control after closure of the valve that is under the control of the thermoelectric current, the ow of fuel should be to the pilot burner only until .the safety control has been reconditioned by reestablishment of the pilot llame, as otherwise gas may issue from the main burner, causing a dangerous condition. Fuel controlling devices have been proposed to permit the manual opening of the pilot burner fuel passage following which the opening of the fuel passage to the main burner is permitted only after the pilot burner has been lighted and the safety control has been reconditioned for safe operation. Devices for this purpose have included a manually operable main valve which directs the flow of gas only to the pilot burner during the starting operation and then, upon proper conditioning of the associated safety control, this manually operated main valve may be advanced to the on position whereupon the supply of gas to the main burner and to the pilot burner is shifted to the outlet side cf the safety shutoff device. Movement of the said manually operable main valve prior to reaching the on position can be accomplished only when the thermostat control lever is in the position for closing the thermostatic valve that determines the flow of fuel to 'the main burner, this being effected by the use of interlocking means between the thermostat and the main valve. Upon reaching the on position, however, the interlocking means may be adjusted to the desired water temperature setting, thereby opening the thermostatically controlled valve in the mainburner supply pasmere.

Another device for accomplishing this purpose s disclosed in U. S. Patent No. 2,361,945 to W. F. Iackson in which the resetting means controls iirectly a valve in the pilot burner passage, effects '.he closure of the thermostatically operated valve.

and also conditions the safety shutoff device to its operative position.

These devices may thus be characterized as providing separate valves for controlling the pilot gasl passage during the resetting operation.

It is an object of this invention to provide an improved safety control which makes unnecessary the use of a separate pilot control valve for er until the pilot has been relighted and the safety control has been reconditioned for safe operation.

Another object o f this invention is to provide an -improved device of the type characterized which is simple in construction, composed of parts that are readily manufactured and assembled, and certain in operation.

Other objects will appear as the description o' the invention proceeds. v

The invention is capable oi receiving a variety of mechanical expressions only one of which is illustrated on the accompanying drawing, and it is to be expressly understood that the drawing is for purposes of illustration only, and is not to be construed as a denition of the limits of the invention, reference being had to the appended claims for that purpose.

The single figure oi' the drawing is a vertical elevation, largely in section. yof a safety .control embodying the present invention.

In the `form shown, a casing i@ of any suitable size, construction and material, and illustrated as formed in one piece, is provided with a threadednipple i i for attachment to any suitable source of gaseous fuel, a threaded nipple I2 for attachment to any suitable main burner and a threaded nipple i3 for attachment to any suitable pilot burner. Interiorly, the casing is suitably subdivided so as to provide three chambers, a chamber i4 in communication with the nipple li, a chamber i5 in communication with the nipple I2 and a chamber i6 in communication with the nipple I3 and also forming a means oi' communication ing metallic parts between the chambers i4 and|5 under operating conditions.

The safety shutoff device is mounted in the chamber I4 and controls communication between the chambers |4 and l0. To this end a valve seat member of any suitable construction. her shown as a ring threadedly engaged in the aperture |9, is provided with a valve seat i9 surrounding the valve port 20. Mounted for cooperation with said valve seat `|9 is a valve member 2| of any suitable construction carried by a valve stem 22. the connection between valve member 2| and its stem 22 preferably being such as to permit slight relative movement between the parts so as to assure perfect sealing whenovalve member 2| engages its seat |9.

Valve stem 22 extends 'through an aperture 23 in a housing member 24 carried by a bonnet 25, as by frictional ilt, spot welding or the like, threadedly mounted at at the outer extremity of the chamber |4. Interiorly of said housing member 24 valve stem 22 is provided with an electromagnet armature member 21 which is also preferably mounted on the valve stem 22 so as to permit relatively free motion therebetween. Projecting into adjacency with armature member 21 is a U-shaped electromagnet core 29 carried by the bonnet 25 in any suitable way and having on its legs electromagnet windings 29 adapted to be energized from any suitable source, such as a thermocouple appropriately positioned so as to be heated by the flame oi the pilot burner. When energized the electromagnet coil 29 provides sulcient attractivev force to hold the ar-l mature 21 in engagement with pole faces 29a oi core 20.

Electrical connection with the electromagnet winding 28 may be effected in any suitable way as by a connector in the form of a central conductor 30 suitably insulated 'from the surroundas by an insulating tube 3|. insulating washer 32 and an insulating cup 33. The inner end of conductor 35 is connected at 35 to one end of the winding 29, while the outer end o! said conductor terminates in a contact disk 35, insulated from the surrounding metallic parts by the insulating cup 33. Theopposite end of the Winding 20 is grounded to the bonnet member 25 as shown at 35. By inserting a suitable contact member into the socket 31 to effect electrical engagement with the disk 35 and grounded bonnet 25 the thermocouple referred to is elecrically connected to the electromagnet winding Valve stem 22 projects beyond the face of 4valve member 2| as shown at 30 and it is provided with an interior chamber 39 having at its outer end an annular plug 40 held therein in any suitable way. Projecting through the aperture in said plug 40 is an operating member in the form of a finger 4| having a head 42 that is normally held against the -plug 40 by a coil spring 43 mounted in the chamber 39.' Interposed between the valve member 2| and the bottom of the housing member 25 is a second coil spring 44 whose force constant is materially less than the force constant of spring 43 so that when a force is applied to finger 4| to raise valve member 2|, spring 44 is readily compressed while spring 43 has negligible compression,

The thermostatically operated valve mechanism is associated with the chamber I5, and to this end a valve seat member 45 of any suitable construction, here shown as a disk threaded into aperture 49, is provided with a valve seat 41v and one or more apertures 49 to permit flow of fuel from the chamber i5 to the chamber I5 when the valvev member next to be described is in open position. Mounted for cooperation with the valve seat 41 is a valve member 40 of any suitable construction provided with a valve stem 50 projecting from the valve member. Valve stem 50 projects through a centrally arranged guide opening 52 in the valve seat member 45 and is provided with two interior chambers 53 and |03 with a partition wall |04 therebetween. Annular plug 54 is held in the outer end of chamber 53 in any suitable manner. Mounted within chamber 53 is a pin 55 having a head 58 between which and the end of the chamber 53 reacts a coil spring 51. Also attached to the valve stem 50, and here shown as made in one piece with the plug 54, is a spring seat 58 between which and the valve seat member 45 reacts a coil spring 59. At the other end oi valve stem 50, chamber |03 is provided with an annular plug |05 which is held in position at the outer end of chamber |03 in any suitable manner. Mounted within chamber |03 is a pin |05 having a head |01 between which and the end of chamber |03 reacts acoil spring |08.

The force constant of kspring 51 is materially greater than that of the spring 59, and the force constant of spring |00 is-inaterially greater than .that of spring 51. Under normal operating conditions whena force is applied to the outwardly projecting extremity 60 of the pin 55, spring 59 is readily compressed while spring 51 has only a negligible compression. However, if valve member 49 is in its open position and a force is applied to finger |05 in a direction for closing the valve member 49, spring 51 can be compressed by movement of pin 55 into the chamber 53. and with negligible compression of spring |00. Valve member 40 may thus be engaged with its seat, 41

notwithstanding that the projecting end 60 of the pin 55 is held against upward movement, as viewed in the drawing, by the thermostat hereinafter described.

The outwardly projecting end 50 of pin 55 engages a diaphragm 5| held in position in any suitable way as by a pair of retaining rings 62 and 50 threaded at 5d into the bore of the chamber and thereby providing a gastight closure with the chamber i5. Diaphragm 6| is designed to be operated by any suitable thermostat mechanism associated therewith. yIn the form shown the thermostat is of the snap acting type and includes a clicker disk 55 carrying a post 66 adapted to engage and deilect the diaphragm 5|. Clicker disk is supported on a seat t1 provided on the retaining ring 62. Engaging said clicker disk Gil is a disk-shaped member 69 having an annular seat 59 for cooperation with the clicker disk 55 and of smaller diameter than the seat 61. Disk shaped member 50 is actuated by a thermostat of any suitable construction, here shown as a known type of rod and tube thermostat. of the bimetallic type comprising a rod 59 composed of a metal having a low coeillcient of expansion, such as a nickel steel containing approximately 36% nickel and 0.2% carbon, and an outer tubular member '|10 of high coefiicient of expansion, such as copper. `The outer end of rod B9 is threadedly connected at 1| to a plug 12 which in turn is suitably connected to the outer end of tubular member 10. The inner end of tubular member 10 is secured in position in any suitable way as by being threaded at 13 into an aperture in the casing |0. The inner end 14 of rod 5S is seated on the disk shaped member 68, and fo:

adjustment of the thermostat in a manner well understood in the art said rod 68 may be provided with a collar located in a chamber 18 formed in the casing i0 and having an arm (not shown) extending exteriorly of the casing i0 so that by rotation of the arm and collar 16 the rod' 88 may be adjusted with respect to the sleeve 18 to predetermine the temperature at which the thermostat actuates the clicker disk 68,

While one particular thermostat and snap actuating mechanism operated thereby have been described -wlth considerable particularity, it is to be expresslyunderstood that the invention is not limited to the mechanism illustrated and described, as any suitable thermostat and any suitable mechanism operated thereby for actuating the thermostatically controlled valve member 4t may be used.

Casing I0 is normally mounted in association with a water tank or comparable means with the thermostat projecting into heat interchanging relationship with the controlling medium. To this end the casing i0 is shown as provided with an elongated collar or boss 11 threaded at l@ for reception in a threaded aperture in the tank or the like so thatthe thermostat 88, 'it is subjected to the temperature of the water or other medium in said tank.

Chamber I8 is provided with any suitable means for actuating the fingers 4i and |86 and thereby the valve members 2| and 49 in proper sequence. For purposes of illustration a cylindrical cam arrangement has been shown comprising a rod 18 provided with a tapered cam 8d circular in cross section for cooperation with ringer 4| and a second tapered cam 8i circular in cross section for cooperation with the finger |06. The position of the parts shown in the drawing corresponds to the normal operating position of rod 19, cam member 8| being in position to engage fingerv i upon slight inward movement of rod 19 to the left as viewed in the drawing, while cam member` 88 is positioned to engage the nger 4i only after an appreciable inward movement of said rod 1S, to the end that nger di will be operated to open the'valve member 2i only after cam member 8i has engaged nger |08 and seated valve member 48 against its seat 417. v

Cam member 80 is also provided with a valve y face 82 adapted to cooperate with a seat, here shown as carried by a plug 8d threadedly received in the opening 85 and provided with an aperture B6 through which projects the rod 'i8 to the exterior ofthe casing l0 where it is provided with a push button 8l. Valve seat 88 surrounds the aperture 86 so that when the valve face 82 of cam member 80 is in engagement with said seat 88 leakage through the aperture 88 is prevented.

The opposite end of rod 19 is telescopically received within and rigidly ixed to a sleeve 8@ which is mounted for telescopic movement within the aperture 88 of the nipple leading to the pilot burner. Sleeve 88 may be attached to rod 18 in any suitable way as by brazlng. Sleeve 88 is provided with suitable apertures 80 so that fuel may flow from the chamber I8 to the interior bore 9i thereof and thence out through the nipple i3. Surrounding sleeve 88 and reacting between the wall of the casing I0 and a spring retaining member 82 is a coil spring 93 which normally urges the rod 18 to the right as viewed inthe drawing. Sleeve 88 is designed to ilt the bore of passage 88 accurately and, in conjunction with the cooperation between rod 19 and aperture 86, effects the proper alignment of the rod 19 with the cam members carried thereby.

The .position'of the valve member 2| as shown in the drawing corresponds to that existing after the pilot burner has failed so that the thermoelectric current flowing through the coil 29 is incapable of holding the armature 21 against the pole pieces 28a of the electromagnet core 28 whereby, under the action of the spring t, the valve member 2| has been moved to engage the seat i8 and thereby discontinue the flow of fuel through the casing lli. It will be observed that in this position of parts no fuel can flow through either of nipples i2 or it even though the thermostat is holding the valve member 48 in its wide open position because the water or other controlling medium is cold.

To reset the device. the rod 18 is moved to the left as viewed in the drawing by manually pressing on button 81. Such movement to the left first causes the inclined surface of cam 8i to engage linger |06 and move the valve member 48 into engagement with its seat 4l so that, when fuel is admitted to the chamber i 8. it cannot flow outwardly through the chamber I5 and nipple i2. If as illustrated the thermostat is then holding the valve member d8 in its open position, said valve member is none the less closed by the foregoing movement because pin can move into chamber B3 against the force of spring 51 as the cam 8| moves the valve member 49 into engagement with its seat.

Further movement of rod 18 toward the left as viewed in the drawing and after valve member 49 engages its seat 41 is accompanied by movement of finger |06 into chamber |03 and the cornpression oi spring |08. Upon said further movement of nod 18 to the left and following the engagement of valve member 49 with its seat t1, the

inclined surface of the cam 80 engages the linger 4| causing the valve member 2| to be raised from its seat, against the force of spring 4t, until the armature member 21 is engaged with the pole faces 28a of the core 28. If after such engagement cam member 80 still tends to move finger 4i upwardly as viewed in the drawing the latter may move into the chamber 38 against the force oi the spring 48 even though the valve member 2| cannot continue to move upwardly, as viewed in the drawing, because of the engagement of armature member '21 with the ends of the U- shaped -core 28. Thereby rod 18 can be moved to its extreme lefthand position without injury to the parts after assuring that armature member 21 is positively engaged with the core of the electromagnet.

While push button 81 is thus held in its innermost position fuel may flow from the chamber i6 through the apertures 80 into the passages 8i and 89 and thence to the pilot burner. The pilot may thereupon be lighted, energizing the thermocouple and therefore reenergizing the electromagnet coil 29 to retain the armature member 21 against. the pole faces, so that valve member 2| is held in its open position after rod 19 is released and moved to its right-hand position by the action of spring 93. Fuel is thus permitted to flow from the chamber I4 into the chamber I and, upon release of the rod 19, valve member 49 returns to its'open position under the action of the spring 51. Thus the fuel may flow both to the main burner through the nipple i2 anemia under the control of the thermostatic valve member i9 and to the pilot burner through the nipple i3. If the rod i9 should be released before the pilot burner has become effective to reenergize the electromagnet coil 29 so as to hold the valve member 2i in open position, valve member 2l will be moved to closed position under the action ofits spring i, again shutting off the flow of fuel to the thermostatically operated valve mechanism as well as to the pilot burner, so that fuel can be readmitted to the pilot burner only after the thermostatic valve member is again closed. Thus fuel may fiow both through the thermostatically operated valve mechanism and to the pilot burner only after the pilot has been reignited and the electromagnet coil 2% has been reenergized sufficiently to hold the valve member iii in its open position. Once the `control has been properly reconditioned, however, the control of the valve member i9 is solely from the thermostatic mechanism which opens and closes said valve as required by the temperature of the medium to which the thermostat is subjected.

It will therefore be perceived that the present invention provides a simple, efficient and foolproof' device which assures that fuel cannot flow to'the main burner until the pilot has been reignited and the safety control has been properly reconditioned for futuresafe operation. As soon as the pilot fails, flow of fuel through the casing,

lboth to the main burner and the pilot burner is discontinued, and fiow of fuel to the main burner may thereafter be reestablished only after the pilot has been reignited and the safety shutoff mechanism has been properly reconditioned forv safe operation. All of this is effected by manipulation of a single member thereby avoiding the use of a separate valve for controlling the pilot gas passage during the resetting operation.

While the embodiment of the invention illustrated on the drawing has been described with considerable particularity it is to be expressly understood that the invention is not limited thereto as the same may receive a variety of mechanical expressions, some of which will now be apparent to those skilled in the art, while changes may be made in the details of construction, arrangement, sizes, proportion of parts, etc., without departing from the present invention.

,While one form of thermostat and one form of ciicker disk type 'of snap actuating mechanismy has been illustrated and described, it is to be expressly understood that the invention isnot limited thereto as any suitable thermostat and operating mechanismfor a thermostatically controlled valve may be used. Also, any suitable form of A electromagnet and source of thermoelectric current may be employed. Reference is therefore to be had to the appended claims for a definition of the invention.

What is claimed is:

1. In a safety control for burners of gaseous fuels of the type including a fuel passage for a main burner, a second fuel passage for supplyingfuel to said first named passage and to a pilot burner passage, a valve for controlling fuel flow through said first named passage, a thermostat having operative connections to said valve, a second valve for discontinuing fuel flow through said second passage and a thermoelectrically closing said first named valve. a member operatively connected to said second valve for opening the same and restoring controlling relationship ywith said thermoelectrically actuated device, and a manually operated device cooperating with said members for operating the same in sequence and enforcing closure of said first valve if open actuated device for controlling said second valve,

a resetting means for said second valve including the combination of a member operatively connected to said first named valve and separate from said first named operative connecting for before opening said second valve.

2. In a safety control for burners of gaseous fuels of the type including a fuel passage for a main burner, a second fuel passage for supplying fuel to said first named passage and to a pilot burner passage, a valve for controlling fuel flow through said first named passage, a thermostat having operative connections to said valve, a second valve for discontinuing fuel flow through said second passage and a thermoelectrically actuated device for controlling said second valve, a resetting means for said second valve including the combination of a member operatively connected to said first named valve and separate from said first named operative connections for closing said first named valve, said operative connections including yieldable means to enable closure of said first named valve when it is being` held open by said thermostat, a member operatively connected to said second valve for opening the same and restoring l controlling relationship with said thermoelectrically actuated device, and a manually operated device cooperating with said members for operating the same in sequence and enforcing closure of said first valve if open before opening said second valve.

3. In a safety control for burners of gaseous fuels of the type including a fuel passage for a main burner, a second fuel passage for supplying fuel to said first named passage and to a pilot burner passage, a valve for controlling fuel flow through said first named passage, a thermostat having operative connections to said valve, a second valve for discontinuing fuel flow through said second passage and a thermoelectrically actuated device for controlling said second valve, a resetting means for said second valve including the combination of a member operatively connected to said first named valve and separate from said first named operative connections for closing said first named valve, a member operatively connected to said second valve for opening the same and restoring controlling relationship with said thermoelectrically actuated device, yieldable means interposed between said last named member and said second valve to enable movement of said member after said second valve is stopped by said thermoelectrically actuated device, and a manually operated device cooperating with said members for operating the same in sequence and enforcing closure of said first valve if open before opening said second valve. g

4. In a safety control for burners of gaseous fuels of the type including a fuel passage for a main burner, a second fuel passage for supplying fuel tosaid first named passage and to a pilot burner passage, a valve for controlling fuel flow through said first named passage, a thermostat having operative connections to said valve, a second valve for discontinuing fuel flow through said second passage and a thermoelectrically actuated device for controlling said second valve, a resetting means for said second valve including thecombination of a member operatively connected to said first named valve and separate from said first named operative connections for 'I5- closing said first named valve, yieldable means i through s main burner, a second fuel vice, and a manually operated device cooperating with said members for operating the same in se quence and enforcing closure o( said first valve 'if open before opening said second valve.

5. In a safety control for burners of gaseous fuels of the type including a fuelfpassage for a main burner, a second fuel passage for supplying fuel to said first named passage and to a pilot v yburner passage, a valve for controlling fuel flow through said rst named passage, a thermostat having operative connections to said valve, a

second-valve for discontinuing fuel flow through said second passage anda thermoelectrically actuated device for controlling said second valve, a

havingv operative connections, to said valve, a

second valve for discontinuing fuel flow through resettingmeans for said second valve including the combination of a member ,operatively connected to said first named valve and separate from said first named operative connections for closing said first named valve, a member operatively connected to, said second valve for opening the same and restoring controllingl relationship with said thermoelectrically actuated device, and a enforcing closure for said first valve if open before opening said second valve, said manually operated device including a single member provided with means for engaging and operating said members.

6. Inl a safety control for' burners of gaseous fuels of the type including 'a fuel passage for a main burner, a second fuel passage for supplying fuel to said first named passage and to a pilot burner passage, aV valve for controlling fuel tflijow id first named passage. a thermostat having ,o rative connections to said valve, a second valve for discontinuing fuel flow through said second passage and a thermoelectrically actuated device for controlling said second valve, a vresetting means for said second valve including the combination of a member operatively connected to said first named valve and separate from said first named operative connections for closing said first named valve, a member operatively` connected to said second valve for opening the same and restoring controlling relationship with said thermoelectrically actuated device, and La manually operated device cooperating with said members for operatingthe same in sequence and enforcing A.closure of said first valve if open before opening said second valve,- said manually operated manually operated device cooperating with said l members for. operating the same in sequence and said second passage and a thermoelectrically actuated device for controlling said second valve, a resetting means for said second valve including the combination of a member operatively connected to said first named valve and separate from sid first named operative connections for closing y said rst named valve, a member operatively connected to said second valve for opening the .same

and restoring controlling relationshipwith said thermoelectrically actuated device, a manuallyv operated device cooperating with said member for operating the same in sequence and enforcing closure of said first valye if 'open before opening said second valve. said manuallyoperated device including a single member provided with means for engaging and operating said members, and resilientmeans cooperating with said single member for normally holding the means thereon out .of operative engagement with said first named members. V

8. In a safety control for burners of gaseous fuels ofthe type including a fuel passage for a main burner.'` a second fuel passage for supplying fuel to' said first named passage and to a pilot burnerpassage, a valve for controlling fuel ow through said first named passage, a thermostat having operative connections to said valve, a second valve for discontinuing fuel flow through said second passage and a thermoelectrically actuated device for controlling said second valve, a resetting means for said second valve including the .combination of a member operatively connected to said first named valve and separate from said first named operative connections for closing said first named valve, a member operatively con- -nected to said second valve for opening the same and restoring controllingrelationship with said thermoelectri'cally actuated device, a manually operated device cooperating with said members for operating the same in sequence and enforcing closure 'of said first valve" if open before opening said second valve, said manually operated device 'including a single member provided with means for engaging and operating said members.

` resilientmeans cooperating with said single member for nominally holding the means thereon out of operative engagementrwith said first named device including a reciprocating rod provided with through said first named passage, a thermostat a valve for controlling fuel flow members, and valve mechanism operable by said single member for preventing leakage of fuel around said manually operated device and normally held close by said resilient means.

PAUL. L. BETE.

` REFERENCES crrsn lThe following references are of record in the file ofthis patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,461,714. February 15, 1949. PAUL L. BETZ It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

w, 1 ,Y Column 7, line 75, for connecting read connections; column 9, line 31, for the Words for said read 0j said; column 10, hne 13, for member read members;

and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Oiice.

Signed and sealed this 23rd day of August, A. D. 1949.

THOMAS F. MURPHY,

Assistant Gommz'ssioner of Patents.