US2465918A - Automatic safety pilot - Google Patents

Description

March 29, 1949. R. E. NEWELL 1 AUTOMATIC SAFETY PILO'l Filed Dec. 11, 1945' Fig.1

Patented Mar. 29, 1949 UNITED STATES PATENT OFFICE Claims.

This invention relates to flame responsive-cutoff valves for automatically closing a main gas supply to a heating burner, and also to a pilot burner, in the event that said pilot burner is extinguished, the operation being termed a one hundred per cent cut-off.

The particular type of device herein described is generally referred to in the art as a pushbutton safety pilot, in which the main cut-off valve is manually pushed open and is latched, or otherwise held open, by a thermally operated mechanism responsive to a pilot flame.

In controls of this character the valve may be held open at a point giving large capacity, and closed with a relatively strong spring, so are preferable for large Water heaters, furnaces, ovens, etc. However valves of this type have been characterized by certain disadvantages, to overcome which it is the purpose of this invention:

First, to provide such a valve in a rugged design. with no external operating parts susceptible to damage.

Second, to insure a quick and positive operation to hold the valve open when the pilot is lighted, and to close the valve almost immediately when the pilot is extinguished, regardless of ambient temperatures.

Third, to provide such a valve, having a mechanically operated thermal element, with a wide and powerful closing movement, without imposing friction, load or strain on its thermal element while the thermal element is heated by the pilot flame.

Fourth, to provide manually operated valve opening means which is self returning to normal position while the valve is latched in open position, whereby the automatic closing of the valve will not be hindered or prevented by friction of sliding or bending parts in the manually operated valve opening means.

Fifth, to provide an automatic safety pilot having a mechanically operated thermal element installed adjacent to a main burner, with an independent pilot gas supply, and means for closing same automatically and simultaneously with the closing of the main gas supply.

Sixth, to provide a manually operative unit for a one hundred per cent cut-off, with means permittin opening of the pilot supply line first, without opening the gas supply to the main burner, and to hold said pilot supply open automatically while the pilot is being lighted and the thermal element is being heated, prior to opening of the main gas supply.

Seventh, to provide for the operation of said control, a rod-and-tube type thermal element having an internal rod adapted to move laterally instead of endwise, by thermal expansion of the tube, and means permitting an external adjustment of the internal rod by rotation of the tube.

Referring to the drawings:

Fig. 1 is a section view of the entire control.

Fig. 2 is a section on the line X--X, Fig. 1.

Fig. 3 is an external side view of the thermal tube and pilot burner.

Fig. 4 is an external view of the outer end of the push button assembly.

Fig. 5 is a section of the middle portion of the control, with the valve parts in a different position from that indicated in Fig. 1,

The main body of the control is indicated in Fig. 1 by the numeral I. The valve closure member 2 is urged toward its closed position on valve seat 3 by sprin 4. 5 is a screw cap, conveniently removable for access to the valve parts within the body I.

The body I is provided with a main gas passage through a chamber 6 that has an inlet 6a, and through a chamber 1 that has an outlet 8. Both inlet and outlet are threaded for connections to other controls and to a main heating burner, not shown.

9 is a detachable push button assembly or manual operating unit, adapting the control to operate as a one hundred per cent cut-off. It is attached to the control by means of a flange Ill, secured by screws II, which are threaded into a boss i2, extending from the control body I. Between the flange Ill and boss l2 a diaphragm I3 is inserted for a gas seal, and also as a second valve closure member.

Pilot burner 14 is provided with ports l5 (as shown in Figs. 2 and 3), adapted to progagate a continuous flame or series of flames [6 which impingeupon one side only of thermal tube H, as indicated in Figures 1 and 2.

Figure 2 illustrates how the flame l6 encircles and heats approximately half of the circumference of the tube H, the opposite side of the tube receiving heat only by conduction. The tube is made of a chromium-nickel alloy having a low heat conductivity and therefore its opposite side is of substantially lower temperature.

This differential in temperature causes a lateral flexing action of the tube H in very quick response to the flame, as described in my prior application Serial No. 572,701, filed January 13, 1945, now Patent No, 2,426,786, granted September 2, 1947.

I8, Figure 1, represents an operating arm, rigidly secured to the outer end of the tube 11, said outer end beng closed gas tight. The opposite or open end of the tube 57 is screwed into a boss it in the body I, the free end of the arm i8 extending through the open end of the tube into the gas outlet chamber '1. On the free end of the arm IS a small circular cam 20 is provided by welding same on the end of arm l8, slightly off center.

A triggeril ,preferably a sheet-metal stamping, is located in the outlet chamber '1, of the gas passage through body i. The trigger 2! is pivoted at 22 in a trigger support member 23, said trigger support member being machined iroma square brass bar, with a reduced round portion at each end, one end being inserted thru a central. hole in the body 1 and riveted asshownat 24.

A flat spring 25 is soldered orotherwise secured at its lower end to the flat side of member 123,

extending between member 23 and trigger 2 l, and passing through a hole in trigger 2!. The

tension of .thisflat sprin is .to ,normally urge the ,upper endofsaid trigger .21 to the left, thereby pushed open by means of the valvestem 28, which is actuated through the .push button 2& in a manner later explained.

When the notch 21 in the valve stem 28 is in a position to be latched and held toopen position "by'the-trigger 2|, the .parts will beas shown in While the pilotflame It remains lighted .Fignl. theparts ,will remain in this. position.

l-Iowever, should the pilot flame become ex- ,tinguished the .tube ,I'l will flex to its normal straight position, swinging the arm l8 in-a manner causing the cam 20 to engage one arm of trigger 2| rocking theupper end-of the trigger out of the notch .21, of the valvestem, as indi cated by dotted lines, thus tripping the .main valvetoclosed position.

Thisactionwill take place in a matter of six to eight seconds from the time the flame isextinguished, regardless of the ambient temperature surroundingtube I1.

As previously mentioned, the flame l6 encircles and impinges on approximately half of the circumferential surface of the tube ll. The midpoint of the flame is in aplane corresponding to the action of trigger 2|, and the axis of valve push rod ,28. It is in this plane that the outer end of tube I! is flexed by the action of flame I 6, said flexing ofthe tube, ina direction away from the flame l6,,causing the free end of the arm 18, and cam 20, to move in the opposite direction, disengaging the cam 20 from trigger 2|. When the flame is extinguished a reverse action takes place; the trigger is engaged by cam .20, and the valve is tripped to closed position, as above described.

The purpose of cam 20 is to obtain a convenient external adjustment of the thermal mechanism with relation to trigger 2|. This is accomplished by simply rotating tube H in one direction or the other, which actionalso rotates the arm l8 and cam 28, thus chang g :its rela- 1 101 to trigger 2|.

,By the above described arrangement all operating parts are entirely enclosed, making it unnecessary for the comparatively delicate thermal action .to be transmitted through packing pins,

,lyusedon an appliance. .type the maincut-ofi valve inthe pilot control is used to also cut off the pilot supply gas.

" sheet brass.

etc., and obtaining a positive release of the valve with the least possible friction.

It will also be noted that since the cam 20 is out of engagement with the trigger 2! when the tube H is in its heated condition, there is no load whatever upon the arm l8 when the tube I I is so heated. Much of the failure of pilot control devices heretofore, has been due to the thermal element being loaded when hot, for long periods of time.

'It is desirable that an automatic safety pilot shut off the gas to the pilot flame as well as to .the main burner, especially where the appliance .on whichit is used has no outside flue connection,

or where bottled gas is used, which is highly explosive.

Heretofore this feature has been available only on thermocouple type pilot controls which may beinstzalled remote from the burner on the inlet side of the main gas cook and thermostat, usual- In safety pilots of this However, .in the present device, which must :be installed adjacent to the main burner, I provide an independent pilot gas supply and a second valve, to cut off the pilot gas supply, thus making it possible to provide a one hundred per cent cut oil on a pilot control having a mechanically operatedthermal element, and installed adjacentthe burner, on the outlet side of any thermostator .maingas cock used in the gas line, it being necessary only to connect the pilot gas supply to .a point ahead of the thermostat.

.I will now proceed to describe the manner in whichthis is accomplished.

Referring to Fig. 1, the flexible diaphragml 3 is preferably made of synthetic rubber or of thin It is moulded or pressed to aconcave-convex form permitting wide movement at its center. At its outer periphery it is flat,,-and serves as a gasket seal.

.Atthecenter of diaphragm [3 a button 31 ,-is

provided, which maybe'either molded in the vdiaphragmo-r be made-of metal, as indicated, the purpose being to provide a flat rigid-area at the center of the diaphragm to render it suitable as a valve closure member. Thebodyportion 3a is recessed at 32 toprovide space forthemovement of the diaphragm I 3. ,At its-center a valve seat 33 is formed, communicating with a central bore 34, having a flat bottom, and. from which a:smaller hole continues through the center of the .bodyr3fl.

.Slidably mountedat the outer end of thebody 3B is thebefore-mentioned push button 29.in.-the form of a hollow cup, and having ,riveted at its center around rod 35 whichextendsthrough-into the bore 34 of the body 30.

. A ;-retracting spring 36,; mounte d,in the body13 0,

normally tendsto urge the push :button 29 toward its outward position. Thepush button :29 islimited in this outward movement-by a rubber collar 31, which is forced over-the rod 35 and into the reduced portion .38of the rod 35 before gitis assembled andrivetedto the push button 29. A gas connection is madetothebody'3ll;at39 permitting gas to enter the bore ,34. Thisgasis supplied through-a line, (not shown) connected to th main gas supply .at a po nt bef re any thermostat or main gas ,cock ;is used, {and :is supp dto the pi t burner 114, through the present control valve, independently .Qf the main gassupply, aswill now b e;describ.ed.

With the main valve closure member 2 and diaphragm l 3 in the position shown in Fig. 1, gas passes from the bore 34 into the recess 32, from whence (see Fig. 5) it passes through small hole 40, through a registering hole 4| in the diaphragm l3, into hole 42 in the main control body I, connecting with the pilot burner l4, which extends from the boss I9 of body I, as shown in Fig. 3. The tapped hole in which the pilot tube I4 is inserted connects directly with hole 42, Fig. 5..

The lower end of valve stem 28, Fig. 1, has an axial bore in which is inserted a light spring 43 and a yieldable pintle 44, the pintle being held in by. spinning or pressing over the end of stem 28. The purpose of this yieldable pintle 44 will presently be explained in the description of operation of the control device.

Operation Should the pilot flame I6 be extinguished the immediate flexing of the tube I! to its normal straight position, and the consequent movement of the free end of operating arm l8, Fig. 1, to the position shown by dotted lines, will operate the trigger 2| to trip the valve 2 to closed position.

As the valve 2 moves toward closed position the lower end of stem 28 is forced down so that the pintle 44 at the lower end of stem 28 engages the button 3| at the center of the diaphragm I3, moving the diaphragm to the position shown in dotted lines I3a, where it contacts the seat 33, thus closing the passage of pilot gas from the bore 34 to the pilot burner l4.

At this point the pintle 44 yields, slightly compressing the small spring 43, by the force of the stronger main valve closing spring 4, so that the stem 28 continues to move downward slightly, allowing the main valve closure member 2 to close completely. Thus both the main gas supply to the main burner (not shown) and the pilot gas supply is completely out off at practically the same instant.

To relight, the operator first pushes the button 29 inwardly and turns it clockwise to the right so that pin 45, which is fixed in the body 30 enters the off-set slot 46 (Fig. 4) of the push button, where it is held by the outward pressure of the retracting spring 36 against the push button 29. The hand of the operator may then be removed from the push button 29, as it will remain in this position, at point B, Fig. 4. As a consequence of this slight inward movement of the push button the rod 35 has moved inwardly as shown in Fig. 5, so that the diaphragm is slightly lifted oiT the seat 33, permitting pilot gas to pass through to burner I 4, in a manner already described. This slight upward movement of the diaphragm causes the pintle 44 to yield further, but, as before explained, due to the stronger spring 4 the main valve is held closed.

After the pilot is lighted, and a few seconds allowed for the thermal element to act to permit movement of the trigger 2| by the spring 25, the push button 29 is turned to the left (counter clockwise) out of the off-set slot 46 and pushed on inwardly so that the pin is in the slot at the point 41 and the push button is at position C shown in Fig. 4. With the push button 29 in this position the inner end of the rod 35 will have forced the diaphragm l3 upward, so that, looking at Fig. 1, it is in the position shown by the dotted lines 13b. This action of course forces the stem 28 and main valve disc 2 to open position where it is latched by the trigger M.

The push button 29 may then be released, whereupon. it will return to the position A shown in Figures 1 and 4, the pin traveling, relatively speaking, up the slot in the push button and around to its original position. The valve and other parts will of course remain in this position as long as the pilot burner is lighted. It may be noted that the entire lighting operation may be performed with one hand.

It should also be noted that should the push button 29 be accidentally forced in it will be stopped by the pin. 45 at position B; atv which point only the pilot gas will pass to burner l4, and

the main valve will not be opened. As soon as such accidental pressure against the push button 29 is released it will return to its outermost position A and the pilot gas will again be cut oif as before explained.

It will be noted that the main valve is easily removed for cleaning; also the stem 28.

The stem 28 is a loose fit in trigger support 23 so there is no possibility of its sticking.

The trigger support 23 together with the trigger, 2!, may be easily inserted through the opening of the main valve, in assembling.

Neither the stem 28 nor the rod 35 are tied in with the diaphragm, but engage it freely, without binding.

The valve seat 33 is made easily accessible by removing the screws I l and the body 30.

The rubber collar 31, seating at the bottom of bore 34 insures a perfectly gas tight closure, regardless of the lit of the rod 35 in the body 30.

I claim:

1. A safety pilot control for gas including a body portion having a main gas passage comprising two chambers therein that respectively have inlet and outlet openings, 'a valve seat with an opening therethrough positioned between the chambers, a valve closure member co-operating with said seat, a spring normally urging said valve closure member to closed position, a push rod engaging said valve closure member, manually operated means for actuating said push rod to open said valve closure member against the action of said spring, a latch-supporting member within said gas passage and rigidly secured to said body, said latch-supporting member having ing adapted to hold and release said push rod to thereby hold said valve closure member open or to release it for movement to closed position, said body being provided with an opening adjacent said trigger, a hollow thermal member extending from the body in line with said opening and communicating with the opening, said hollow member being closed at its outer end, an operating arm within said hollow thermal member having one end secured to the outer or closed end of said hollow thermal member and its opposite or free end positioned to engage said trigger, and a pilot burner secured to said body in fixed relation to said hollow thermal member and provided with ports adapted to propagate a flame to heat one side only of said hollow thermal member, causing said member to flex laterally at its outer end, and to thereby actuate said operating arm and trigger in a plane corresponding to said flexing action.

2. A flame responsive control for gaseous fuels including a housing, a main gas passage through said housing, a valve seat and valve closure member in said gas passage to close off the flow of gas therethrough, a spring yieldably urging the valve.-

;.closure member :to its seat, :rmanual umeans tex- ;ternally ,operated :foreopening said valve:closure member against :1the;spring..pressure, latching mechanism within :said .gas :passage :for holding '-:-said waive :closure .member in open position,

-.:therma1iy operated means :adapted to (trip :said

"latching mechanism--;-upon the extinguishment :of :a pilot flame, said ithermal mechanism icomprising a tubular element secured ;.to :said mousin :and projecting therefrom, with its outer ,end closed. andsupporting an :internal operating arm extending into :said housing and engaging :said llatching mechanism, ameans for propagating a :pilot :flame in 1a manner-to heat one 'side only 10f said tube to cause it .to :flexrat. its .outer tend-and .zto actuatersaid internal :arm in :a lateral :direc- ;tion .rrelative to the axis of said .tube,:andta .latchoperating device mounted onitheifree endiofrsaid operating arm :and adjustable radially "roilthe tube.

3. A :flain-e'iresponsive :controlfor gaseous 1 1 11618 including. ahousing, amain ;gas passage through said housing, a valveiseat and valveclosurexmemleer insaid gas passage to closeofi theflow :ofvgas therethrougnarspringfor moving the saidmemher to closed ;position, .a push :rod Within :said housing at or manually opening said valve :closure member against the valve closing spring, aitrigl ger support member'rigidly secured within said housing, a trigger pivotally 'supported by ;said :member, a spring :adapted to rock said trigger into engagement with said push :rod, ,to hold said push rodand said valve closure member in open position, a tubular thermally responsive eleillfilll', extending iromsaidhousingadapted to be z laterally flexed by the impingement upon .onezside thereof of a.;pi1ot flame, means propagating :a pilot flame in contact with said element-in -a ,manner to directly heat one side only, itoecause said element to flex inaegiven plane, and in'a direction away'from-said flame, an operating :arm ,secnred .at the outer endaofsaid elementrandiextending within the same, to a,point within said housing, :said operating arm being adapted :to move laterally within said tubular :element in one direction with the flexing of -;said tubular ielement in-t'he presence of said pilotflame :and to return to a normal position upon rthe'iexitinguishment of said pilot flame, :a tripping ele- .ment ontheend ofsaid operating arm, withinasaid :housing, and positioned to engage said tri ger, andmeans for adjusting said-arm to :shiit :the tripping element in a:direction normal to the axis ,ofpsaidypush rodto effect release-of saidzrodand -:said-valve closure member. for movement-toclosed position as said operating arm approaches ,its 'normal position, after *extinguishment of said pilot-flame.

.4. A safety pilot control ior ga-s including a :body -portion provided with apassageway having agas inlet and ages outlet, 2a valverseat between :said .inlet and outlet, pr0vided with an opening :therethrough, a 'valveiclosure rnemberon one ,side ioi .said opening -;adapted to cooperate with ,said

seat, a closing-spring -normally ,urginB said valve closure .member to closed :position, "a manually operable :stem :on :the opposite .side of :said valve opening adapted to contact :said valve closure memberand to open it against the :actiomof said spring and having a latch-engaging shoulder, a

latching mechanism :comprisinga trigger, ,a trigger spring, :and a support membenhaving'a :cen- *tral bore :for said .-stem,.:means for' pivotally sup- :porting :the trigger and :thetriggerspring on the *supporting izmember, ;said ,:latchin g mechanism .tbeing of :smaller diameter than .the \valve rseat anpening,iwherebyiinmaybe lnserteiiithroughesai'd :va'lve ;opening' and secured rto: said valve :bodyson :the side :of :said waive iopening opposite "to :said 5 iolosure member, .anda zhollow thermal tube rclosedzatzits :outer :end, extending .from said-body, and Lihaving fan internal operating arm :responsive iniits movement to :the thermal :action .:of:said :.tube,,-saidanmsextending within saidzbody :on the side of said valve opening :opposite to .saidwalve :olosure member, and; adapted. toimovessaid trigger gout :oii +.engagement with said manually :operable stem, against the :tension of :said trigger spring, whemsaid thermal tube is .inan unheated-condition, and ;t.o;move t ...l ermit:return ofsaiditrigger, .by the trigger :Zspring, into en agement wiithjsaid manually operable valve-opening stem, toflatch said valve closure member in open position, when said thermal tube isin a heated condition.

990 5. A safety pilot control for gaseous fuels inlzcludingia;body;provided with a :main jgasipassage, :amain valve adapted to cut oil the gaspassing :throughsaid-body, avalve-closing.springmmanually operated stemforopeningsaidvalve against the pressure of the valve closing spring, a ;piv,ot,ed trigger ion the body I, for releasably latching the valve 1Qr en,;a;light-.spring normally :urging ,said tri ger into engagement with shoulder --on .said rstcrn tohol'd said main valve in opengposition, themovement OfiSElid trigger being limitedibyzits engagement-with said-steam, a thermal element comprising a hollow tube extending outwardly .ir om,-said -body,'with its inner end inlflxed relation to said trigger, burner port means in fixed relation toisaid tube and adapted Ito propagate aflame to heat one side of said tube-only, adjacentits outer end portion, thereby causing .said outwardlyextending, portion to flex laterally out of alignment with-its-normal aXis,-and-zan operatiingrarmsecuredlto the-said tube at a point remote from said innerlend and extending back into'sald body, its free .end being positioned .to-engage said trigger when said tube is cold, to holdsaid-trigger tout ofrengagement with said stem, thetotal movement of said when the said tubeiszheated flexed to its maximum point being substantially greater than the limited movement of the trigger, whereby said arm may disengage itself .from said trigger and thus free itself of the load -.developed by the tension of the trigger-while said tube is in its heated condition. .6. An automatic safety control forgasinclud- 'illg a \body member, a control "member .mounted therein, thermal mechanism for operating said control member, said thermal mechanism being responsive to the heat of a name, and comprising a .rotatably mounted tube extending from the 'bodymember in which said control member is situated, an operating arm secured to the outer end of said tube and extending lengthwise within said tube to a position adjacent said control lmember, .cam means connected to thefree end of said operating arm and .operatively associated with said control member, and adapted to .be adjusted relative to said control member by roatation of said tube, and a pilot burner having ,port means adapted to direct a heating flame in a manner to heat one side only of said tube, to ,cause-it toflex and consequently to move the free .end of said operating arm laterally within said .tube, in "a given plane, whereby said arm and cam means Will operate said control member in accordance with the presence or absence of said .heating flame.

7. A control :device including a control memher, a thermally responsive mechanism, a lever between said control member and thermal mechanism for transmitting the action of said thermal mechanism to said control member, said thermal mechanism including an operatin arm provided with a cam at one end to engage said lever, and secured at its opposite end to a thermal tube mounted in said control device and projecting therefrom, the tube and the arm being rotatably adjustable as a unit, whereby the adjustment of said cam relative to said lever may be varied, and means for applying heat to one side only of said thermal tube to cause it to flex in a given direction at all adjusted positions of the tube, and to actuate said arm and cam in a lateral direction relative to said tube, thereby effecting operation of said lever and said control member in response to the application or removal of heat from said thermal tube.

8. A flame responsive automatic pilot valve for cuttin off the fuel supply to both a main heating burner and an independent pilot burner, including a housing provided with a passageway having a gas inlet, having a gas outlet to said main heating burner, and also having independent gas passages connecting to a pilot burner, a first valve in the main gas passage through said housing, a sprin yieldably urging the valve toward closed position, a second valve in the independent gas passage connecting with said pilot burner, said valves being operatively connected, an external actuating member adapted to first open said second valve to admit gas to said pilot burner, and then to open said first valve to admit gas to said main heating burner, means responsive to the flame of said pilot burner adapted to retain said first valve in open position while said pilot flame is burning, and to release said valve when the pilot flame is extinguished, and yieldable connecting means between the first and second valve for closing the second valve during the movement of the first valve toward its closed position, the said first valve closing immediately after said second valve has become closed.

9. A flame responsive automatic gas cut off control adapted to cut off the fuel supply to both a main heating burner and a pilot burner, including a housing having a main gas passage and a pilot gas passage, a gas seal dividing said passages one from the other, a main valve in the main gas passage, a main valve closing spring, thermal operated means responsive to the heat of a pilot flame adapted to hold said main valve open or release it for closing, a second valve in the pilot gas passage, means operatively connecting said main valve with said second valve, and operating through said gas seal to effect closing of said second valve by the closing action of said main valve, manual means, externally operated, for opening said second valve to admit gas to said pilot passage only, and means effec tive upon further movement of said manual means to open said main valve and thus supply gas to a main burner.

10. A flame responsive control for gaseous fuels including a housing, a main gas passage through said housing, a valve seat and valve closure member in said gas passage to cut off the flow of gas through said passage, a spring urging the closure member to its seat, a push rod supported at one end on said valve closure member, a manually operable member engageable with said rod, to force said valve closure member to open position by manual movement of the manually-operable member in one direction, a pilot burner adapted to propagate a pilot flame, thermal means responsive to said flame, latching means operated by said thermal means and adapted to hold said push rod and valve closure member in open position while said pilot flame is burning and to release said push rod to permit automatic return of said valve closure member to closed position, when said pilot flame is extinguished, and a retracting spring acting upon said operating member to immediately return it to its former position upon release thereof by the operator, after the valve closure member has become latched in open position, whereby the said operating member will not impede the return of said valve closure member to closed position upon release of the latching means.

ROBERT E. NEWELL.

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

UNITED STATES PATENTS Number Name Date 1,906,868 Mustee May 2, 1933 1,943,045 TePas Jan. 9, 1934 2,011,111 Mantz Aug. 13, 1935 2,023,640 Morrow Dec. 10, 1935 2,363,525 Higley et al Nov. 28, 1944

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