US2118886A

US2118886A - Fuel burner control system

Info

Publication number: US2118886A
Application number: US87716A
Authority: US
Inventors: Frederick D Joesting
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1936-06-27
Filing date: 1936-06-27
Publication date: 1938-05-31
Anticipated expiration: 1955-05-31

Description

May 31, 1938. F. D. JoEsTlNG- 2,118,886

FUEL BURNER CONTROL SYSTEM Filed June 27, 1936 2 Sheets-Sheet l //v VE/Y Toe 5y HAS. ATTORNEY May 31, 1938. F. D. .JoEsTlNG 2,118,886

FUEL BURNER CONTROL SYSTEM Filed June 27, 1956 2 Sheets-SheewI 2 @if /r/s Arrone/v Patent-. Mey 31, 193s FUEL BURNER CONTROL SYSTEM Frederick D. Joesting, Minneapolis,.Minn., as; signor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application June 27, 1936, Serial No.l 87,716

1? Claims. My invention relates to a fuel burner control system and more particularly to one employing means for interrupting the supply of fuel to the main burner in the event of the pilot burner be- `ing extinguished.

It is customary with certain types of fuel burner control systems to employ a constantly burning vpilot for igniting the fuel supplied to the main burner. Where such a pilot is employed, some means is usually provided for preventing fuel from being supplied to the main burner in the event that the pilot burner is extinguished. Such a means is commonly referred to as a safety pilot. The safety pilot arrangement may take any of various forms. It may operate directly through a valve in the main fuel line or it may operate through a control device such as a valve or switch, which in turn controls the operation of main fuel valve which is normally controlled y some controlling condition. In certain of these systems, it is also common to provide a valve which controls the flow of gas to the pilot burner and is under the control of the safety pilot arrangement so that in the event of the pilot burner being extinguished, the supply of fuel to both the pilot burner and the main burner is interrupted. The present invention, While not so limited is particularly applicable to the latter type of system. v

An object of the present invention is to provide a novel fuel burner control system employing a pressure motor operated main valve which is controlled by a control valve, and a pilot Valve,

wherein means are provided for closing both the pilot and main valves in the event of the pilot burner being extinguished and wherein means are provided for rst opening the pilot valve while positively holding the control valve in a position causing the main Valve to be closed and, then upon the pilot burner being lighted, moving the control valve to a position causing opening of the main valve.

A further object of the present invention is to provide a novel arrangement for the operation of two valves which are to be operated successively, the second being opened only after a pre determined condition has been established as the result of the operation of the first valve.

A further object of the present invention is to provide a novel safety pilot arrangement ernploying a thermocouple which is located in the path of the pilot flame and controls the opening and closing of a control valve of a pressure Inotor operated fuel valve in accordance with whether the pilot is ignited or not.

Qther objects of the invention will be apparent from the accompanying specification, claims, and drawings, of which: f

Figure 1 is a sectional view of a portion of novel valve apparatus of the present invention, the section being taken along the line i-i of Figure 2;

Figure Z isa perspective view with a portion broken away of the valve apparatus of the present. invention;

Figure 3 is a sectional view oi the valve apparatus shown in Figures 1 and 2, which section is taken along the line 3 3 of Figure 2;

Figure 4 is a detailed sectional view with a section taken along the line Q-t of Figure 3;

Figure 5 is a detailed sectional View of another portion o my valve apparatus, the seo tion being taken along the line ti--iiof Figure 3; and in which lfigure 6 is a schematic view of a novel fuel burner control system employing the valve apparatus of the present invention.

Referring to the drawings, Figures l to 5 generally show the details of a novel valve mechanism which is particularly adapted for use in a gas burner control system. The valve in general comprises a diaphragm valve, the operation of which is controlled by a control valve. The valve mechanism further comprises a pilot burner Valve which controls the supply of fuel to the pilot burner. When the pilot burner is ignited, the position of the control valve and consequently of the main valve is controlled in accordance with a bulb located in the space heated by the main burner. In the event of the pilot burner being extinguished, both the main and the pilot burner valves are closed through a thermo-cou ple arrangement.

Referring first to Figure 3 of the drawings, it will be noted that there is shown a diaphragm valve having a housing, the lower section of which is designated by the reference numeral i i. This housing is provided with an inlet connection `I2 and an outlet connection i3. Adjacent the outlet connection i3 there is provided raised annular portion ill which serves as a valve seat to control the flow ci fuel between the inlet and. outlet. A valve disk i5 of any suitable construc-- tion is adapted to seat on valve seat iti.

The upper section of the valve housing is gene erally designated by the reference numeral it. Clamped between the upper and lower sections II and` I5 is a diaphragm I3 which diaphragm' serves as the movable wall of a, pressure motor actuating the valve disk I5. The diaphragm I8 is provided with an aperture through 4its central portion and a sleeve 20 extends through this aperture, being secured to the diaphragm I8 by a nut 2|. The lower portion of sleeve 26 is provided with a pair of spaced

shoulders

22 and 23. Secured to the interior of the lower section Il of the valve housing is a bracket member 25 to which is pivotally secured a lever member 26. Secured to lever member 26 through suitable fastening means 21 is a valve disk I5. 'I'he outer end of the lever member 26 is slotted and two spaced arms of the slotted portion extend between the

shoulders

22 and 23 of sleeve member 20'. It will be readily seen that the lever member 26 serves as a means for transmitting movement of diaphragm I8 to the valve disk I5 so that upon upward movement of diaphragm I 8, the valve disk I5 is raised from its seat.

Due to the fact that sleeve 20 has a passage extending therethrough, a restricted communication between the two sides of the diaphragm I8 is provided. As may be apparent from a subsequent description of the operation of the device, it is imperative that this restricted passage be open at all times. Accordingly, there is provided a spring member 29 which has an elongated stem portion 30 extending through the passage in sleeve 20 and terminating in an eyelet 3i which prevents the stem portion of spring 29 from being pulled out of sleeve 20. As will be more or less obvious, the upper movement of diaphragm I8 Will cause the upper portion of the spring 29 to abut the upper portion of the valve casing causing stem 30 of spring 29 to move downwardly through the aperture in sleeve 20. The result is that each time that the diaphragm I 8 is actuated, the stem portion 30 of spring 29 is reciprocated in the opening of sleeve 29 thus acting to clean the passage of any deposits that may collect therein.

In order to better understand the function of the apparatus to be subsequently described, it may be noted that the pressure motor comprising diaphragm I8 is of the type wherein one side of the diaphragm is constantly subjected to the full force of the motoruid which may be the gas controlled by the valve. A bleed opening is provided through the diaphragm and the other side is subjected only to the pressure of the fluid which passes through the bleed opening. A bleed pipe is connected to the side of the diaphragm to which the gas bleeds and is provided with a control valve which when open permits the gas to bleed away from the chammr faster than it can bleed into the chamber by reason of the opening in the diaphragm. When the control valve is closed, the gas bleeding between the two sides of the diaphragm is allowed to accumulate in the chamber to which it bleeds with the result that the diaphragm is moved in the opposite direction. It is usual to arrange the pressure motor with respect to the valve actuated thereby so that the control valve in the bleed line is open when it is desired to open the valve and closed when it is desired to close the main valve.

Referring now to Figure 1, the control valve for the bleed gas leaving the upper side of the chamber I8 is generally designated by the reference numeral 35. 'I'his valve is located in a boss 36 projecting interiorly from a wall 3l of the upper portion I6 ,of the valve housing. A screw threaded gland 31 is secured in this boss and serves as a guide for a valve stem 38 to which is secured a valve head 39, cooperating with a valve seat 40 formed by the juncture of a larger recessed portion 4I .with a smaller'recessed portion 42 of the boss 36. The valve stem 38 is provided with a collar 43 and interposed between collar 43 and the gland nut 31 is a spring 44. As shown.

more clearly in Figure 5, the valve chamber communicates `with the upper side of the diaphragm f I8 through a passage 46. Also communicating with the valve chamber on the other side of the valve seat is a passage 41 which is threaded at its outer end to receive a pipe leading to some suitable point of disposalof the bleed gas.

The means for normally controlling the position of the control valve 35 includes a lever 56 bearing against the valve stem collar 43, the position of which lever is determined by theop'posing actions of a spring 5I and a bellows 52, which latter member is in turn controlled by thev vapor pressure within a bulb 53. Theflever is pivotally mounted on a .U-shaped bracket 48 secured to the bottom wall of the control housing. The

in a vaporous state at or about the. temperature which it is desired to maintain in the room being heated and which is connected through flexible tubing 54 with the interior of a chamber 55 surrounding the vbellows 52. Bellows 52 has connected thereto a stem member 56 which has a conical pin 51 which is adapted to bear against a member 58 secured to lever 50 which is provided with a conical recess in each side thereof.

'The spring 5| is interposed between a disk 60 provided with a conical point 6I seated in one of the conical recesses of member 58 and a collar member 62, the position of which is determined by a screw member 63. Screw member 63 is threadedly connected with collar 62 and has rigidly secured at the outer end thereof a handle member 64 which facilitates rotation of screw 63 and a consequent movement of disk 62 inwardly or outwardly changing the tension on spring 5I. Since the position of lever member is determined by the opposing action of the bellows 52 and the spring 5|, it will readily be seen that the temperature at which lever arm 50 is actuated from one position to another can be changed by varying the tension of spring 5I. This serves as a means for regulating the temperature at which the-control valve is moved from one position to another position and consequently the temperature at which the burner is brought into operation. The handle 64 is provided with a pointer 65 which pointer cooperates with a dial 66 which bears suitable indicia thereon to indicate the setting of the thermostatic apparatus 4previously described.

As indicated in Figure 2, the lever member 50 is provided with an arm 61 to which is secured an extension 12 of magnetic material which member cooperates with a permanent magnet 13. The effect of this magnet is to tend to retain lever 50 in a position shown in Figure 1 so that it is necessary for there to existan appreciable diierential between the pressures exerted by spring 5I and by bellows 52 before lever 50 is moved to a position permitting valve 35 to open. After the temperature has dropped to the point anasse Vwherein valve 88 is open and the temperature to which bulb 88 is subjected begins to rise causing the pressure exerted through bellows 82 to exceed the pressure exerted by spring 8|, the eil'ect of the magnet 18 is negligible so that the lever 58 does not begin to close valve 85 untilan appreciable rise in `temperature has taken place. In

this manner, a differential is secured between the temperature at which the valve opens and at which it closes. If it were not for the arrangement comprising the magnet 18, thevalve 85 would be constantly opening and closing and occupying-various intermediate positions between open and closed positions. In an apparatus of this type. this would be highly undesirable.

A stop member 10 is secured to a side wall 1| of the Vcasing I8.l This stop member serves to limit the outward movement of the lever 58. 'I'he inward movement of the lever is limited by reason of valve 89 engaging with valve seat 88.

The numeral 15 is Aused to generally indicate a valve which is adapted to control the ow of gas to a pilot burner. This valve is located in a boss 18 projecting from the wall 3|. A gland nut 11 is threaded into the boss 18 and acts as a guide for a valve stem 19 to which is secured a valve head 88. The valve head 88 is adapted to cooperate with valve seat 8| formed by the juncture of a recessed portion 82 of comparatively large diameter with a recessed portion 83 of relatively small diameter. The valve stem 18 has secured thereto adjacent its outer end a collar 85. Interposed between collar 85 and the gland 11 is a, spring 88 which serves to bias the valve head 80 away from the valve seat 8|. Referring to Figures 3 and 4, it will be noted that the passage formed by the recessed portion 83 communicates with a passage 81 which in turn communicates with a similar passage 88 in the lower section of the valve housing. The passage 88 connects with the space on the underside of the diaphragm, which space is in constant communication with the in'let l2. Connecting with the passage formed by recessed portion 82 is a passage 80 which is provided with screw threads at its outer end to facilitate the connection thereto of a pipe 8l which may lead to a pilot burner. Inter-posed in-the passage 98 is a needle valve 82 which may be adjustedvto regulate the ilow of gas to the pilot burner. A lock nut 93 cooperates with needle valve 92 to lock the same in any desired adjusted position. It will be seen that when the valve 15 is open,` gas may flow from the inlet side of the valve housing through

passages

88, 81, 88 and 98 to pipe 8| which, as previously indicated, preferably leads to a pilot burner of suitable construction.

As indicated in a previous portion of the specification, the valve mechanism of the present invention is provided with an arrangement wherein upon the pilot burner being extinguished,

. both the control valve 35 and the pilot burner valve 15 will move to closed position. The mechanism for so moving these valves will now be described. Secured to the side wall 1| of the valve casing is a housing member 95 which is provided with a cover 98 apertured at 81. Extending through this aperture 91 is a rod 98, which rod has secured at its end adjacent the valves 35 and 15, a collar 98. An elongated striplike member is pivotally secured to the collar member 88 and is so disposed relative to the valve structures 35 and 15, previously described, that upon rod member 88 being moved in the direction of the valves, the member |88 is caused to bear upon the end of stem 88 oi valve 88 and upon the collar 88 or valve 18. The cover 98 is recessed at |8| and located in this recessie a spring |82 i which bearsat one end against the cover 88 and at the other end against the collar 99. This spring has a strength greaterthan the combined strength of

springs

48 and 88 so that so long as the position of rod 98 is determined solely by spring |02, this spring urges the'rod 88 in the direction of the valves 35 and 15 with suilicient i'orce that member |00 is caused to hold both valves in closed position.

Secured at the outer end of rod 98 is an armature member |84. This armature member is guided in its movement by flanges |85 projecting from the cover 98. The armature is adapted to cooperate with a magnet generally indicated by the reference numeral |01. This magnet is provided with a core |88 of very high permeability and the windings |09 of the magnet are of relatively large wire for a reason subsequently to be set forth. It will be readily seen that when the magnet |01 is energized and the armature |08 is held in engagement therewith that member |08v will be suiilciently retracted, that valve 15 will be moved to open position by the spring 88 and that valve 35 will move to' the position permitted by lever 58.

A thermo-couple is employed to energize the magnet |01. This thermo-couple is generally deslgnatedby the reference numeral I |0 and comprises the usual elements and H2 of diierent thermo-electric characteristics which are joined at 3 to form the hot junction of the thermocouple. The two elements and H2 may be of any desired materials which have suitable thermo-electric characteristics to `generate current suiilcient for the energization of magnet |01. As one example of the materials which may be employed, it has been found particularly success,- ful to employ an outer element Hl of stainless steel. The stainless steel may be of any form which is capable of resisting the heat of a pilot llame. In the example referred to. the inner element was made of "Constantan which, is an alloy consisting of approximately fifty per cent nickel and fty per cent copper. The outer member is secured through a copper reducing sleeve H8 to a copper tube H5. Secured to the inner member ||2 is an insulated conductor H6. Conductor'llv is secured through a connecting sleeve ||1 to one end of the winding |08,of magnet |81. A sleeve ||8 of insulating material is disposed over the connecting sleeve ||1 and surrounding the sleeve l l1 is an outer coupling sleeve I8 which serves to secure the copper tube H5 to the housing 85 and which also serves to electri- 'cally connect the copper tube ||5 with the other end of the winding |09 of magnet |01. The size of the copper tube H and the conductor |18 is comparatively large so as to oier an extremely low resistance to the conduction of current therethrough. This is imperative inasmuch as the voltage generated by the thermo-couple is relatively small, and in order to obtain a suicient ow of current Athrough lthe winding of magnet |01, it is necessary that alll of the conductive members have a comparatively low resistance.

Slidably mounted in an enlarged portion of the wall 3| of valve casing i6 is a pin |25. This pin is provided with a button portion |28 which is slidably mounted in a recessl |21 in the valve casing wall. Located. in this recess |21 surrounding the pin |25 is a spring |28 which serves to bias the pin Cil |25 outwardly. A small pin |29 extends transversely through pin |25 to form a stop to limit the outward movement of pin |25. It will be noted that the button |26 extends outwardly from the casing |6 so as to be readily engaged manually from the exterior of the casing. Upon pushing button |26 inwardly, the inner end of the pin |25 .engages member |00. If this movement is continued, member |00 will be moved in the direction of wall 1| of the valve casing, being pivoted about the end of the valve stem 38 of valve 35. 'I'his movement will cause armature |04 to approach the core |08 of the magnet |01. 'I'his movement will also cause member |00 to move away from collar 85 permitting spring 86 to move valve 80 to open position. The result of .push button |26 being moved entirely in, is, accordingly, that armature |04 is brought into engagement with the core of magnet |01 and that valve 15 is moved to open position. At the same time, valve 35 is held closed even more securely than before due to the fact that member |00 is pivoted about the end of valve stem 38.

Upon the push button |26 being actuated in the manner described in the previous paragraph, if the magnet is ener'gized so that armature |04 is held in engagement therewith, the release of push button |26 will permit member |00 to be moved away from the end of valve stem 38. What happens is that upon armature |04 being so held, the member |00 is free to pivot about its pivotal connection with collar 99 so that the biasing springs 44 and 86 are effective to move member |00 to a position wherein both valves 35 and 15 may be in open position. In the new position, member |00 will have substantially the same angular position as shown in Figure 1 but the position will be shifted transversely in the direction of wall 1I of the valve casing to an extent sufcient to permit the opening of valves 35 and 15.

This voperation will be more clearly understood in connection with a subsequent description of the operation of the valve in a fuel control system.

In Figure 6 of the drawings, there is shown, in schematic form, the valve mechanism of the present invention incorporated in a novel fuel control system. Although the valve mechanism is shown in schematic form, the same reference characters have been employed in connection with this portion of Figure 6 as were used in the description of the valve mechanism in connection with the previous figures. It is believed that from the previous description, the relation of the various elements of the valve mechanism in Figure 6 will be readily apparent so that substantially no further description of the same will be Vset forth in connection with this valve.

.Referring toAFigure 6, a gas burner is desig-- nated by the reference numeral |35. This gas burner is supplied with gas through a pipe |36 connected to the outlet I3 of the main gas valve previously described. Connected to the inlet I2 of the gas valve is a pipe |31 which leads to a gas main.

A pilot burner is designated by the reference numeral |38. This burner is connected through pipe 9| to the passage 90 which is controlled by valve 15 as described in connection with Figure 4. For the purposes of illustration, a pipe |40 is shown as connecting the underside ofthe valve casing with valve 15 in lieu of

passages

88, 81 and 83.

In order to simplify the showingA of the valve mechanism in this gure, a pipe I4I is shown as connecting the upper portion of the valve casing with valves 35, instead of

passages

42 and 48. The pipe 48 referred to in connection with Figure 5 is shown as extending to a point adjacent the pilot burner |38 so that the gas escaping therethrough will be consumed in the pilot burner flame.

Operation The various elements are shown in Figure 6 in the position which they assume when the burner is out of operation and when the pilot burner |38 is extinguished. If it is desired to start the operation of the system, it is first necessary to light the pilot burner |38. In order to do this, button |26 is pushed inwardly in the manner previously described. This pushing inwardly of button |28 causes member |00 to be pivoted about the end of the valve stem 38 of valve 35 causing the armature |04 to move into engagement with the magnet |01 and at the same time to permit biasing spring 86 to move the valve 15 to open position. The result is that gas is admitted through pipe |31 underneath the diaphragm, through pipe |40, valve 15 and pipe 9| to the pilot burner |38, the gas escaping from this pilot burner |38 being ignited by any suitable means.

As the button |26 is held inwardly, holding armature |04 in engagement with magnet |01, the energization of magnet |01 by reason of the thermo-couple IIO becoming heated by the pilot flame will soon be suicient to hold armature |04 in engagement with magnet |01. When this condition occurs, the release of button |26 will release the end of member |00 adjacent the pin |25 and will permit the biasing spring 44 of valve 35 to move valve 35 to a position permitted by lever 50. Usually when the burner is being started up in this manner, it is because the temperature of the space heated by the burner has fallen .to a point where there is a demand for heat.

Under these conditions, the position of lever will be such that upon member |00 being held by themagnet I 01, spring 44 will be effective to move the valve 35 to open position. When this takes place, the gas above the diaphragm I8 is permitted to bleed off through pipe I4I through valve 35 and pipe 48. Since gas can bleed oilin this manner faster than it can bleed through the diaphragm, the effect is to relieve the pressure above the diaphragm. As previously explained, the underside of the diaphragm is constantly subjected to the pressure of the supply gas so that as soon as the pressure above the diaphragm is released in this manner, diaphragm I8 moves upwardly causing valve I5 to move to open position and permitting gas to ow to burner |35.

The operation of the burner will normally continue until the temperature in the space heated thereby has risen to the point wherein the bellows 52 is able to overpower springs 5I and 44 and move valve 35 to closed position. Upon this taking place, the escape of gas from the upper side of the diaphragm is interrupted. The gas will continue to flow through the passage in the diaphragm, however, and in a very short period of time the pressure will be built up in the chamber above the diaphragm sufficiently to cause downward movement of diaphragm I8 and the closing of valve I5.

If during the operation of the valve as previously described, the pilot burner flame is for any reason extinguished, the hot junction of the thermo-couple IIO will no longer be heated with a result that magnet |01 is deenergized. The deenergization of this magnet will release the armature |04 permitting spring |02 to move aliases member- |00 to the position shown in Figure 1 wherein this member -is eiective to hold both valves 35 and 15 closed. The closing of valve 35 will interrupt the supply of fuel to the burner |35 and the closing of valve 15 will interrupt the supply of fuel to the pilot burner |30. In this manner, the danger of an explosion arising from gas being admitted to an unignited burner is eliminated. With the apparatus described, the extinguishment of the pilot burner flame not only causes closing of the main gas valve Abut also causes closing of the pilot burner valve.

In the previously described operation of the resetting mechanism comprising the pin |25, it was assumed that the pilot burner was properly ignited and that the thermo-couple ||0 became heated sufficiently to energize magnet |01 and hold armatureA |04 in engagement therewith. IfI

for some reason the pilot burner is not properly ignited, the release of push button |26 will cause the pilot burner valve 15 to be closed and the parts to again assume the position shown in Figure 1. It will be noted that the inward movement of pin |25 by actuation of push button |26 does not cause the opening of control valve 35 so that a reciprocation of this member does not admit gas to the main burner unless the pilot burner is ignited. By the arrangement described, it is impossible for someone to accidently admit gas to the main burner, which gas is unignited, by pushing button |25. 'I'he only time that actuation of push button |26 will open the valve 35 and consequently cause admission of gas to the main burner is when the pilot burner is ignited while push button |25 is Iheld inwardly during such actuation. Moreovery not only is the control valve `not open duricngreciprocation of the resetting member, but thisv'alve is held even more rmly against the seat during such operation than normally.

While I have described my invention as applied to a fuel burner control system, certain features thereof are deemed to be applicable to the con- .trol of any two valves which are to be operated successively by some actuating means. Moreover, while I have described the operation of the main valve as being controlled by a control valve, it is to be understood that in lieu of the control valve, some other control device might be substituted without departing from the scope of the invention. It is to be understood that the specific `embodiment of my invention shown and described is for purposes of illustration only and that my invention is to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a fluid fuel burner control system, a main burner, a pilot burner, a main valve controlling the iiow of fuel to said main burner, a pressure motor for operating said main valve, means for supplying a pressure uid to said motor to operate the same, a control valve for controlling the pressure in said motor, said pressure motor being operative when saidvcontrol valve assumes a iirst position to hold said main valve in closed position and when said control valve assumes a second position to move said main valve to open position, controlling means including a detrol valve is held in said first position, an electromagnet adapted to hold said member in a different position wherein said control valve is under the control of said controlling means, and means for controlling the energization of said electromagnet in accordance with the absence or presence of a flame at said pilot.

2. In a uid fuel burner control system, a main burner, a pilot burner, a main valve controlling the flow of fuel to said main burner, a pressure motor for operating said main valve, means for supplying a pressure fluid to said motor to operate the same, a control valve for controlling the pressure in said motor, said pressure motor being operative when said control valve assumes a first position to hold said main valve in closed position and when said control valve assumes a second position to move said main valve to closed position, controlling means including a device responsive to a normally controllingcondition for varying the position of said control valve, and means operative to move said control valve to said rst position in the absence of a iiame at i said pilot, said last named means comprising a member adapted to cooperate with said control valve and biased to a position wherein the control valve is held in said first position, a magnet adapted to holdsaid member in a different position wherein said control valve is 'under the control of said controlling means, and means for controlling the energization of said magnet comprising a thermo-couple having its hot junction located in the path of the pilot burner iiame.

' 3. I n combination, a pair of valves each movable from a iirst to a second controlling l,position, one of said valves being adapted when moved to its second controlling position to make possible the establishment of a condition which should exist prior to the movement of said second valve to its second controlling position, means biasing each of said valves to its second controlling position, yieldable means for holding said valves in said first controlling position against the action of said biasing means, holding means including a device responsive to said condition for holding said yieldable means when said condition exists, in a retracted position wherein the position of the valves is not affected thereby, and reciprocable means operable upon actuation in one direction to move said yieldable means to a position wherein it may be held by said holding means upon the existence of said condition and wherein it is ineffective to hold said first valve closed but effective to hold said second valve closed, said yieldable means being operative upon actuation of said reciprocable means in the opposite direction and upon being held by said holding means to assume said retracted position wherein said second valve is also free to move from its first controlling position.

4. In combination, a pair of valves each movable from a first to a second controlling position, one of said valves being adapted when moved to its second controlling position to make possible the establishment of a condition which should exist prior to the movement of said second valve to its second controlling position, means biasing each of said valves to its second controlling position, a member adapted to engage said valves adjacent its respective ends, yieldable means acting on said member intermediate said valves in a direction and with a force such that said valves are held in said i'lrst controlling positions against the action of said biasing means, holding means including a device responsive to said condition for holding said member when said condition exists at a point intermediate said valves and in a position such that said member does not restrict the movement of said valves, and reciprocable means Vfor engaging said member adjacent the end thereof opposite said second valve and tilting said member about said second valve to simultaneously move said first valve to its second controlling position and said member into a position wherein said holding means may engage the same if said condition exists, said biasing means being operative in the event of said holding means being effective and upon release of said reciprocable means to 'move said second valve to its second controlling position.

5. In combination, a plurality of valves each biased to open" position, one of which when open makes possible the' establishment of a condition which should exist before the second valve is opened, yieldable means including a pivoted member effective to hold said valves in closedvcondition against the action of said biasing means, holding means including a device responsive to said condition for holding said yieldable means in a position wherein said valves may move to open position, and a reciprocable member engaging said pivoted member and operable upon movement in one direction to push said yieldable means to a position wherein said first valve is open and said second valve closed' and wherein said holding means is adapted to hold said yieldable means, said pivoted member being operative upon said yieldable means being so held and upon said reciprocable member being moved in the opposite direction to assume a position wherein said second valve may move to open position.

6. In a control system, a pair of valves each controlling a different condition, a biasing means associated with each of said valves for urging the valve to a rst position wherein the respective condition controlled by it may be established, common biasing means acting on said valves in opposition to and with a greater force than said individual biasing means to move said valves to a second position, means for tilting said common biasing means to a position wherein said common biasing means is ineffective to oppose the individual biasing means of one of said valves so as to cause said valve to be moved to its first position, and means including a device responsive to the condition established by the movement of said one valve to its rst position to hold said common biasing means in a position wherein upon release of said tilting means, said common biasing means is ineffective to oppose the individual biasing means of the other valve.

7. In combination, means for establishing a predetermined condition, means including a valve for establishing a second condition upon the rst condition being established and upon said valve being moved from a first to a second controlling position, a rst biasing means acting to bias said valve to said second controlling position, a second biasing means acting when in a rst position in opposition to and with greater force than said first biasing means to hold said valve in said first controlling position, holding means including a device responsive to said first condition for holding said second biasing means upon the establishment of said rst condition in a second position wherein the valve.. is not affected thereby, and actuating means for moving said second biasing means from said ilrst to a third position wherein the same is still effective upon the .valve holding means, said first biasing means being operative upon release of said actuating means and upon the holding means being effective as the result of the presence of the first condition to move said second biasing means to said second position and to move said valve to said second controlling position.

8. In combination, a pair of valves, biasing means for each valve urging the same to open position, a lever member engaging each of said valves, a second biasing means effective on said lever member at a point intermediate said valves and acting in opposition to and with suilicient force relative to the first mentioned biasing means to hold said valves closed, a reciprocable actuator adjacent one of said valves and adapted upon movement in one -direction to pivotally move said lever member away from the valve adjacent said actuator and about said other valve, and means to pivotally hold said member adjacent the point at which said second biasing means acts when said member is so moved, the first mentioned biasing means of said other valve being operative upon movement of the actuator in the opposite direction to move said lever member when so pivotally held in a position wherein it does not prevent opening movement of either valve. l

9. In combination, a pair of valves, biasing means for each valve urging the same to open position, a lever member engaging each of said Hvalves, a second biasing means effective on said lever member at a point intermediate said valves and acting in opposition to and with sufficient force relative to the first mentioned biasing means to hold said valves closed, a reciprocable actuator adjacent one of said valves and adapted upon movement in one direction to pivotally move said lever member away from the valve adjacent said actuator and about said other valve, and holding means comprising a magnet and armature one of which is pivotally connected to said lever member adjacent the point at which said second biasing means acts and the other of which is rigidly mounted, the armature and magnet being so spaced that when said member is so moved said armature and magnet are moved relatively into holding engagement with each other, the rst mentioned biasing means of said other xvalve being operative upon movement of the actuator in the opposite direction to move said lever member when so pivotally held in a position wherein it does not prevent opening movement of either valve.

10. In a iluid fuel burner control system, a main burner, a pilot burner, means for regulating the ow of fuel to said main burner including a control device movable between a rst position in which the flow of fuel is prevented and a second position wherein said flow is permitted, a pilot valve for controlling the flow of fuel to the pilot burner, controlling means including a device responsive to a normally controlling condition for moving said control device between its two positions in accordance with the value of said condition, meansresponsive to the presence or absence of a name adjacent said pilot burner and operative upon the pilot flame being extinguished to move said control device to its first position and said pilot valve to its closed position, and means including a reciprocable element for resetting said control device and said pilot valve when so moved, said resetting means being operable upon movement of said element in one direction to cause said pilot valve to open while hold- ,main burner, a pilot burner, means for regulating the iiow of fuel to said main burner including a control device movable ybetween a i'lrst position in which the ilow of fuel is prevented and a second position wherein said ilow is permitted, controlling means including a device responsive to a normally` controlling condition for moving said control device between its two positions in ac cordance with the value of said condition, means responsive to the presence or absence of a ame adjacent said pilot burner and operative upon the pilot flame being extinguished to move said control device to said rst position independently of said controlling means, said means comprising a member biasing said control device to said rst position, a magnet for holding said member in a positionwherein said control device is under the control of said controlling means, and means for energizing said magnet in accordance with the absence or presence of a ame at said pilot.

12. In a uid fuel burner control system, a main burner, a pilot' burner, means for regulating the ow of fuel to said main burner including a control device movable between a rst position in which the ow of fuel is prevented and a second.

position wherein said flow is permitted, controlling means including a device responsive to a normally controlling -condition for moving said control device between its two positions in accordance with the value of said condition, means responsive to the presence or absence of a ame adjacent said pilot burner and operative upon the pilot flame being extinguished to move said control device to said rst position independently of said controlling means, said means comprising a member biasing said control device to said rst position, a magnet for holding said member in a position wherein said control device is under the control of said controlling means, and means for energizing said magnet comprising a thermocouple having its hot junction located in the. path of the pilot burner flame.

13. In combination, a pair of valves, one of which is adapted to control a condition which should exist before the other valve is opened, and lactuating means for said valves including a reciprocable memberA and a device responsive to said condition, said actuating means being eiective upon said member being moved in one direction to cause said ilrstA valve to be moved to a position making possible the establishment of said condition while applying part of the force applied to said reciprocable member to said other valve to hold the same closed, and upon said member being moved in the opposite direction to cause said second valve to be opened in the event of said condition having been established.

14. In combination, a pair of valves, one of which is adapted to control a condition which should exist before the other .valve is moved from a rst to a second controlling position, and actuating means for said valves including a reciprocable member and a device responsive to said condition, said actuating means being effective upon said member being moved in one direction to cause said first valve to be moved to a position making possible a change in said condition while applying part of the force applied to said reciprocable member to said other valve to hold the same in said rst position, and upon said member being moved in the opposite direction to cause said second valve to be moved to said 'second position in the event of said condition having been established.

15. In combination, a burner, a device adapted upon being moved to a first position to establish a condition which is desirable only when said burner is ignited, a lever adapted to bear against said device, yieldable means urging said lever into engagement with said device so as to hold said device in a second position, holding means comprising an armature unit and an electro- `magnet unit, one of said units being iixedly mounted and the other pivotally connected to said lever at substantially the same point at which said yieldable means acts on said lever, whichpoint is spaced from that at which the lever engages said device, a thermo-couple having its hot junction located in said burner ame and connected to said electromagnet unit, said thermocouple being effective when said burner is ignited to energize said electromagnet unit suiliciently to hold said two units together against the action of said yieldable biasing means, and an actuating member adapted to engage said lever and eiective upon being moved in one direction to rock said lever about said device and move said two units together whereby said device is free to move to said first position only after return movement of said actuating means and upon said electromagnet unit being energized.

16. In combination, a burner, a valve adapted upon being moved to a rst position to establish a condition which is desirable only when 'said burner is ignited, a lever adapted to bear against said valve, yieldable means urging said lever into 'engagement with said valve so as to hold said valve in a second position, holding means comprising an armature unit and an electromagnet unit, one of said units being xedly mounted and the other pivotally connected to said lever' at substantially the same point at which said yieldable means acts on said lever, which point is spaced from that at which ythe vlever engages said valve, a thermccouple having its hot junction located in said burner flame and connected to said electromagnet unit, said thermocouple being effective when said burner is ignited to ener- Yglze said electromagnet unit suliiciently to hold 17. In combination, a burner, a valve adapted upon being moved to open position to establish a condition which is desirable only when said burner is ignited, a lever adapted to bear against said valve, yieldable means urging said lever into engagement with said valve so as to hold said valve in closed position, holding means comprising an armature unit and an electromagnet unit, one of said units being xedly mounted and the other pivotally connected to said lever at substantially the same point at which said yieldable means acts on said lever, which point ls spaced from that at which the lever engages said valve, a thermocouple having its hot junction located in said burner flame and connected to said electromagnet unit, said thermocuple beupon being moved in one direction to rock said lng eective when said burner is ignited to enerlever about said valve and move said two units togize said electromagnet unit suiiliently to hold gether whereby said valve is free to open only said two units together against the action of said after return movement of said actuating means r yieldable biasing means, and an actuating memand upon said electromagnet unit being energized. 5

ber adapted to engage said lever and effective FREDERICK D. JOES'IING.