US2924387A - Modulating and on-off fuel control apparatus - Google Patents

Description

Feb. 9, 1960 c. E. HAJN`Y i l 2,924,387

MODULATING AND ON-OF'F FUEL CONTROL APPARATUS Filed sept. 15. 1958 s sheets-sheet 1 u I u Source j 33-- i i I Inl. my /05 52 r vx" i i 37d jjj! v 1 I?" /05 O6 72 7a F 9 5\ 0 3 'm2 /0/ 0 6/ /728 /GV a 7 9 2.9 /8 22 v l ff* @5 '2y N Q f @a nu@ l /5- Feb. 9, 1960 c. E. HAJNY .MODULATING AND ON-OFF FUEL CONTROL APPARATUS Filed Sept. 15, 1958 5 Sheets-Sheet 2 6% Efira/n Feb. 9, 1960 c. E. HAJNY 2,924,387

MODULATING AND ON-OFF FUEL CONTROL APPARATUS Filed Sept. 15, 1958 5 Sheets-Sheet 5 United States Patet AND ON-OFF FUEL CONTROL APPARATUS Charles E. Haiuy, Milwaukee, Wis., assigner to Bso Inc., Milwaukee, Wis., a corporation of Wisconsin Y Application September 15, 1958, Serial No. 761,666

o 46 (Cl. 236-1) f MoDULATmG Inthe development of modulating apparatus for con-i trolling the iow of fuel to fluid fuel burning equipment, the Voperating characteristics ofthe fuel burner are an important consideration. For every burner there is a Safe minimum amount of fuel which is required for the maintenance of a stable flame. `On the other hand, fuel in amount substantially greater than the aforementioned safe minimum must be supplied to the burner for safe ignition thereof.

It is a general object of the present invention to provide an improved modulating fuel control apparatus having a modulator valve actuated by a modulating condition responsive,` for example temperature responsive, actuating'mechanism to provide modulation of the fuel ow to a main burner, said apparatus permitting the burner to be safely ignited at any time, regardless of what the response of said actuating mechanism to the ambient temperature may be at the time.

More specifically, it is an object of the invention to provide an improved apparatus of the character described which does not require that the room temperature cool to the lower end of the modulating range before the modulator valve can be opened sutliciently to permit safe ignition.

Another object of the invention is to provide an improved apparatus of the aforementioned character wherein during an ignition operation the burner may be ignited Withja full burner capacity flame and holds said ilame for a predetermined controlled interval, after which the burner is returned to the control of the modulating mech- Another object of the invention is to provide an improved modulating fuel control apparatus of the class described including an on-off valve as well as a modulator valve, there being means for positioning the modulator valve in ignition position at any time that the on-oi valve is opened.

Another object of the invention is to provide an improved modulating fuel control apparatus of the characterdescribed, wherein the modulator valve can throttle the fuel down to a minimum amount consistent with maintenance of a safe llame, and the on-ot valve provides for complete shut-olf of the fuel.

Another object of the invention is to provide an improved modulating fuel control apparatus of the aforementioned character wherein the modulator valve is modulated, by the actuating mechanism between a minimum safe lowfp'ermitting position and a full burner capacity ignition position "inf response to the changesin the amoperable to overcall said actuating mechanism and'to po-` sition the modulator .valve in vsaid ignition position when the on-oi valve' is opened, irrespective of -the response of the actuating mechanism to the ambient temperature at the time. t 1 .ou A further object of the invention is to provide an improved modulating control apparatus ofthe character described wherein the modulator valve is biased towardj, the minimum flow-permitting position, and the overalling auxiliary actuating means actuates said valve to said ignition position against said bias when the on-off valve is closed, said auxiliary actuating means releasing said modulator valve to the control ofsaid actuating mechanism upon opening of said on-oi valve, and there being time delay means for retarding the return of the modula tor valve to the control of said actuating mechanism after the on-ol valve is opened, said time delay being sutlicient to insure safe ignition of the burner.

A more specific object of the invention is to provide an improved modulating control apparatus wherein the auxiliary actuating means takes the form of a diaphragm connected to the modulator valve and exposed on one side to the uid pressure of the fuel on the upstream; side of the ori-off valve and exposed on its other side to,L

the fluid pressure on the downstream side of saidfon-oi valve, whereby closure of said on-otf valve causes move,- .g ment of the diaphragm and modulator valve in a valve opening direction against the bias of said valve, and opening of said on-off valve equalizes the iluid pressure on the opposite sides of the diaphragm to permit movement of the modulator valve and diaphragm in a valve closing direction under said bias. x

Another specific object of the invention is toprovide l an improved apparatus of the character described wherein the time delay means comprises a unidirectional valve closing direction.

Another object of the invention is to provide an im- Idashpot mechanism connected to the modulator valve* and operable to retard the movement of the latter` in a proved apparatus of the character described wherein the on-oif valve is provided with an electro-responsive operator powered from a source of electric energy and under the control of a condition responsive device, for example a thermostat, independent of the modulating mechanism.

Another object of the invention is to provide an irnproved fuel control apparatus of the aforementioned character wherein the modulating mechanism modulates the modulating valve member between the minimum ow i position and the ignition position in response to normal lluctuations in temperature, and the thermostat cycles the on-ol valve in response to predetermined high .tem-

plete embodiment of the invention, and wherein like characters of reference indicate the same parts in all of v the views:

Figure 1 is a fragmentary longitudinal vertical sectional view of one form of the improved modulating fuel` control device, the associated fuel burning apparatus and the electrical control circuit therefor being shown bient temperature, there being auxiliary actuating means semi-diagrammatically;

Figure 2 isa plan view ofthe improved-modulating''-- fuel' control device, themodulating actuating-mechanism,"

Siem-Mies shownin Figures l andy 3. :The upper end of `the"sten1` 67 is also rounded, and iixed to said stem adjacent its upper end is a spring retaining disc 70. A coiled compression spring 71 surrounds the stem 67 and bearing sleeve 66, having one end in abutment with the retaining disc 70, and having its opposite end resting onthe bottom plate 34.`

A bell crank lever 72, which may` be channel-shaped in transverse cross-section, is pivotally mounted on a pin 7 3V carried bythe side walls 37 and 38. The side flanges of one ar-rn'l-ll of the lever 72 are notched as at 74. The adjacent end` of the stem 56 is flattened, as at 7S, and passesthrough a suitable aperture in the web portion of 'the lever 72 adjacent the notches 74, and a pin 76 extends through the ilattened portion of the stem 56 and is positioned in the notches 74 as shown. The other arm 111 of the lever 72 rests on the upper end of the stem 67,4 and the bias of the 'spring 71 urges thelever 72 in a clockwise direction (as viewed in Figure 3) to thereby seat the pin 76 in the baseof the notches 74. A set screw 77 having a lock nut 78 may be threaded through the casing endy wall 35 and4 may be adjusted to limit the clockwise movement of the lever 72. It is apparent that upon contraction of the fill in the bellows 51 the bias of the spring 57 causes a counterclockwise force to be exerted on the lever 72 and a downward force to be exertedgon the stems 67 and 26 as well as on the valve member 20, said movement being against the bias of the springs 71 and 27. It is also apparent, however, that during expansion of the iill in thebellows 51v no4 substantial moving force is exerted by the 'stem 56.on the lever 72,7but the valve member 20 and stems 26 and 67 are moved upwardly and lever 72 is, Vrotated in a clockwise direction by the bias of the springs 71 and 72.

vIn'rthe illustrated embodiment of the invention the adjustment screw 77 may be so positioned that the valve member 20jcan`not fully close, the minimum open position `of said valve member permitting sufficient fuel ow to maintain avstable flame at the burner 6 when the onotf valvey7 isopen. lt is preferable, however, to permit the valve member 20 to close completely, and to utilizea ,by-pass afforded by the passage 86 which communicates between/ thecharnbers 14 and 16 as shown in Figure 3. YAn adjustment screw S7 intersects the passage 86 fto provide controlof the amount of fuel ow through said passage, the amount of fuel rpermitted to ilow through'said passage being sufficient to maintain a stable arne at the burner 6 as aforementioned. Means are provided forldisposing the valve member 2G ina full open or kignition position whenever the on-.off valvev7, is opened, said means including a diaphragm 79 forming a chamber 30 with the recess 24 of `the body 13 and held in place by a coverplate 81 which sealingly clamps thelperiphery'ofy the diaphragm 79 to form a chamber 82 therewith. The diaphragm 79 is provided with la backing plate 83 which is suitably xed to the lower'I end of thestem 26 as shown. A passage 84 Figure l) aiords communication between the chambers v1 6 and 80, and an angular passage 85 aiords communication between the chambers 15 and 82.

l Itv willbe noted'that when the valve member 23 of the ori-off valve 7 closes, the fluid pressure in the chambers 15 and 82 drops to atmospheric, whereas the pressure in the chambers 16 and 80 builds up to actuate the" diaphragm 79 and its plate 83, stem 26 and valve member 2 0 downwardly, to move the valve member 20 to its ignition position against the bias of the spring 27. Thisa'tuat-ion of the valve member 2t? is independent of the position of the stem 26, and if the valve member 23 is opened when the remaining parts of the device are in the position shown, the arm 30 connected to the stem 26 is swung downwardly away from the stem 67 asthe stem 26 and valve member 20 are moved downwardly withA the diaphragm '7'9V and itsplate 83. When the'valve member 23 is opened, the-pressures on the opposite sides of the diaphragm 79 become equaliz'ed and the stem 26 and valve'member 20 are urged in a valveclosing direction under-the bias of the spring 27 until the arm 30 reengages the stem 67 tol thereby! place the valve member 2) again under the control of the modulating mechanism 10.

Means are provided for retarding the aforementioned return movement of the valve member 20 so that fuel is permitted to flow through the valve 8 in substantial quantity and' for a substantial period of time after opening of the valve 7, in order to permit proper ignition of the fuel at the burner 6 with afull burner capacity ame. In the illustrated embodiment of the invention this time delay means takes the form of the uni-directional' dashpot mechanism 12 shown most clearly in Figures 2 and 3. Thebody'13 is formed with afectangular recess 8S separate from the chamber 16 and closed by the bottom plate 34 of the lcasing 33. Referring to Figure 2, the pivot shaft 31 extends-rotatably througha transverse bore 89 which communicates between the chamber 16 and recess 83, and said shaft is formed with an external annular groove for receiving asealing ring 90,

Within the recess 88 one end of an arm `91- is fixed to the pin 31. Adjacent the oppositev end ofthe arm 9`1the casing 13 is formed with a vertical bore 92 which'opens into the bottom of the recessy 88. A stem 93 is fixed `at its upper end to the arm 91, as by a transverse pin 94, and depends into the bore 92 asshown. A tubular piston has a loose fit within the bore 92 and is connected to the lowerend of the stem 93 as bya pin 96. Thepiston 95 has .a lowery end wall provided with an aperture 97, there being a ball type check valve 98 adapted'tto` seat in said aperture. The piston 95 is also formed withfa'crossbore 99, and a pin 100 limits the movement of the ball 98 within the piston 95. The recess 88 andthe bore 92, as well as the interior of the piston 95, are filled with a fluid, for example mineral oil, to 'provide the necessary fluid friction for dashpot action.

It is apparent that asthe arm 30is swung downwardly during opening of the valve member 2), the arm 91 is simultaneously swung downwardly to move the piston 95 downwardly within the bore 92. The piston 95 can move freely in a downward direction within the bore 92'since the uid in said bore displaced by-said piston movement can ilow upwardly through the aperture 97 and cross-bore 99 as well as through the radial clearance around the outside of said piston. However, when the on-oif valve 7 is opened and the valve member-20 begins'tomoveupwardly under the bias of the spring 27, this upward movement is retarded by the'iluid friction in the dashpot mechanism 1,2, since the piston 95 cannot move freely in.V an upward direction. The aforementioned retardation occurs because the ball valve 9S, upon'upward movement of the piston, seats on and closes theaperture 97, thereby limiting the flow of-the dashpot Huid displacedby piston movement to the path around the piston 95 only. As a result, a time delay is providedwhicli holds the .valve member 20 open for a predetermined period after the 0in-off valve 7 is opened.

The on-oi valve 7 may be operated in anysuitable manner. In the illustrated embodiment of the. invention the valve 7 is provided with a solenoid operator 9 having a. threaded mounting in a suitable internally threaded bore 101 in the casing 13. The operator 9 has a reciprocatory stem 102 which is suitably connected Yto vthe valve member 23 as by a pin 103. Thefoperator 9 is connected in circuit with a suitable source `of electrical energy as by conductors 104 and 105. A circuit controlling device 106, which may be condition responsive, as for example a room thermostat, is interposed in the operator circuit for cycling the operator 9, and hence the valve 7, in response t'opredetermined changes in the temperature sensed by said thermostat. The thermostat'l may; also be `located .at'the comfort level in the space being contracted condition, and the bellows fittings 54 is in abutment with the end of the guide sleeve 52 of the bellows end tting 50. The spring 57, acting against 4the bellowsA end fitting 54 and through the stem 56, lever 72, and stems* 67 and 26, holdsgthe modulating valve member 20 in its lowermost or wide open position, permitting maximumvgas flow to the burner 6, whereupon said burner is ignited by the pilot burner 107. As the room, and therefore the control bulb 65, heats up, the

bellows 51 gradually expands and throttles the gas flowthrough the valve 8 until the valve member 20 eventually seats-on the valve seat 19. At this time the only gas flow to the burner 6 is that which can flow through the bypass 86 and through the clearance around the stem 26 in bore 25, and as previously mentioned, said flow is the `minimum sufcient to maintain a safe flame at the burner 6. On warm days when the minimum safe llame supplies more heat to the room than is lost from the room,

the thermostat 106, acting at a high limit, snaps off the .Operator 9 to close the valve 7.

When the valve 7 closes, the fluid pressure of the fuel immediately builds up in the chamber 80 and drops to atmospheric in the chamber 82. This pulls the modulating valve member 20 down to wide open ignition position burner 107. -The stem 26,'valve member 20 and arm 30 are moved slowly upwardly until the arm 30 reengages the stem 67 to again place the valve member 20 under the control of the modulating mechanism 10.

It is apparent that the improved fuel control apparatus permits the burner 6 tovbe ignited with a safe full burner capacity flame and to hold this flame for a predetermined period of controlled duration irrespective of the response of the modulating mechanism to the temperature t sensed ,by the bulb 65, and also irrespective of the setting of the adjustment knob 59 of said modulating mechanism. Y

Figure 4 shows another form of the invention in which the modulating bellows mechanism 49 controls the operation of both the modulating valve 8 and the on-off valve 7. In this form of the invention the thermostat 106 shown in Figure 1 can be omitted. In Figure 4 the parts indicated by primed numerals correspond to parts indicated in Figure l by the same numerals unprimed. A circuit controlling device 106', which may take the form of a`normally closed switch, is interposed in the conductor 105' connecting one side of the solenoid coil 9' to the source. The switch 106' is mounted within the casing 33' and has a spring-loaded stem or push button 112 positioned for engagement by an end portion 113 of the bell crank lever 72.

During normal fluctuations in the temperature, the portion 113 of the arm 72" does not engage the stem 112 of the switch 106', and therefore, said switch permits current flow from the source to the solenoid coil 9', which, in turn, holds the on-off valve 7 in open position. When the temperature of the room reaches a predetermined high limit, however, the portion 113 of the arm 72" engages and depresses the button '112 to open the switehsltlt'v and deenergize the solenoid coil 9', where-l upon .theson-o valve 7'` closes. Cooling of the room below the high limit temperature moves the portion 113 of lever 72' out of engagement with the button 112, thereby vpermitting closure of switch 106 and reenergization of the solenoid 9', whereupon the latter opens the on-off valve 7.

Referring to the form of the 'invention shown in Fig ure S'of the drawing, the improved modulating fuel control apparatus there illustrated comprises a'fuel control device indicated generally by the numeral` 5' tand having a valve body 13' provided with an inlet chamber 14',

. an outlet chamber and an intermediate chamber 16'.

The control device 5 is interposed in the fuel supply line to a fluid fuel burner 6' and controls the flow of gaseous fuel to said burner by means of an on-olf valve 7' and a high-low modulating valve 8 serially arranged in the fuel stream, there being an electroresponsive operator 9' for the on-off valve 7, and an electrore'sponsive operator 10 for the high-low v alve 8. Conditionresponsive, for example temperature responsive, circuit-controlling means is provided to control the energization ofthe operators 9 and 10', and hence the operation of the valves '7' and 8. Fluid pressure responsive auxiliary actuating mechanism 12 including time delay or movement re tarding rmeans coacts with the valve 8 to afford safe ignition, in a manner which will hereinafter more fully appear. A bore 17 affords communication betwen the `chambers 14 and 16', there being an annular valve seat 18' surrounding said bore in the chamber 14' and with body 13'.

which the high-low valve 8 is cooperable. A bore 19' affords communication between the chambers 16 and 15', there being an annular valve seat 20.' surrounding said bore within the chamber 16 and with which the on-ofl valve 7' coacts.

The auxiliary actuating mechanism 12' affords a closure for a bottom opening 21 in the chamber 16' of the valve The mechanism 12 may, if desired, be made up as a subassembly for attachment to the body 13', said mechanism comprising a plate 23 having a peripheral rim of increased thickness, and a dished cover plate 24' between which and said plate a flexible diaphragm 25' is marginally clamped as shown. The aforementioned subassembly may be held together by a drawn ring 26 having a radially inwardly directed annular flange 27' for marginally clamping a flexible diaphragm 28 between itself and the rim of the plate 23' as shown, `said ring 26 also having a radially inwardly rolled annular edge clampingly engaging the periphery of the cover plate 24 as shown. f The mechanism 12' may be attached to the body 13 by means of screwsv 30' as shown. The cover plate 24' and the diaphragm 25' afford a chamber 31' in which a helical compression spring 32 is disposed, one end of said spring engaging the cover 24', and the other end engaging a back-up plate 33' fixed to the underside of the diaphragm 25', as by a rivet 34. A passage 35 extending through a wall portion of the valve body 13, the flange 27', the clamped margin of the diaphragm 28', the rimV of the plate 23', the clamped margin of the diaphragm 25 and an inner marginal portion of the cover 24 affords communication between the outlet chamber 15 of the body 13' and the chamber 31.

The plate 23', is formed with a relatively large aperture 36' and with a restricted aperture 37' as shown. Surrounding the margin of the aperture 36 on the underside of the plate 23', said plate is provided with an annular valve seat with which a reed type check valve 38 coacts. The plate 23 and the diaphragm 28 form a chamber 39', and said plate and the diaphragm 25' form a chamber 40', both of said chambers being filled with a suitable hydraulic fluid. A back-up plate 41 and a generally U-shaped connecting member v42' are fixed to the upper side of the diaphragm 28', as by nut and bolt members 43' and 44', respectively.

A force transmitting connection is provided between the valve member S'and` the-,auxiliary actuating mech,-

closing t o f valve member 7 thfeiebyy permitting. sufficient l Yerjizf.' dr to provide "t least the minimum amonnt of necessari/for the maintenance o'fa stable name i dy "1 3' is`prc'ividedl with I,a by-pass 4 9 affording comunication between the chambers 14T4 a'nd,1 6 as shown. An'adj'stmcnt 'sci-ew 50 is }provided for the adjustment the amount of fuel' which can flow through' the pas- "S'ge,

In the illustrated embodiment of the invention the electricalenergyv-for powering the electroresponsive actatofs' and 1 0 is derived 4f`r c`i m j`z i line 'comprising conductors 5 1Han'cl 52.y vIt is understood, of course, that the current supplied mythe' actuators 9' and 1o' be of any suitable or desired magnitude,'including 'that v"vided Ibyfax the rmoelectric generator. O ne te'rof 1the` electroresponsive vactuator 10'y is`connec te d Vc luit with the line Wire 51f by a conductor 52g', the

isistance element 55. `"l'he otherf terminal ofthe actuator 1Y0 i's `connected in' circuit'pwith `the line wire 52'v through a vconductor 54' `and a yco dition responsive circuit-controlling device 5 6' comprising a stationary contact 57' anda isn `p` leaf Contact 58', AOne terminal ofthe actutorl `9 `,is' conne`cted in circuit with the tap of the resistance elementSSf bya conductor 59', and the other terminal of said actuator is vconnected in circuit, with Ithe line' wire 52 by a conductor 60 having interposed therein a condition responsive circuitcontrolling device 61' comprising a stationary contactoZ- and a coacting snap `1efeonzaet63t-i 1 The snap leaf eemaers ss' and 63' v stilatig snguesflf 211.11.65. respectively WlllCli hendepres'sed, i.`e movedtoward the right'infthe drawL 'ifrlggftectisnapping of the 'snap leaves into engagement (with the coacting iixed contacts, and when y released perthe leaves 'to snap outof engagement with said iixedcontacts. j, l' "i While the response l o f the circuit-controlling devices j56 ""and 61' may each be under the control of a separate condition responsive actuatingfmeans, itis preferredv to jutilize a single actuating means for both fof said devices. The actuating means rnay take anumber of different fori ris, and in theillustrated! embodiment, takes the form of avapor-filledl bellows 66 havingfa'n adjustablyxed "end Wall 167.' ei'igfag'ejd by4 an adjustment screw 68' lthreaded through a fixed support member 69. The opposite .end walL 70 of the bellows 66' is movable andrhas `fixed thereto` an axiallyl projecting stem 71V having shoulder means Y'l2' for coacton with theA snap leaf tongue Vostfand shoulder means 73 for coaction with thoflsnapleaf tongue 165. :Thevstem 71 carriesatiits outer end an abutmentmember 74 which engages one bend of a helical compression spring 75. An abutment member V76 `engages the opposite end of said spring and is provided with a stem 77' axially slidable .in a fixed bearing 78' .and having its outer end engageable by a rotary cam 79 carried by a shaft 80. Suitable means (no t shown) is provided 4for manually adjusting the resilient@ nationalthacamtmslnlef 79' sndfthsrs.-

adjusting the "compressive force exertdo'n thebel'- terflvingfinterposed therein tapped electrical re- 1ewtj66fy t1se spring, 1s'. Adjusfmearsf :as pressive` force exerted on 'the bellows 66 affords an adjustment o f the control points of the circuit-controlling devices l"56' and,61' Asshown in the drawing, the .electrical resistance 55 is disposed adjacent the bellows o6' 'to afford anticipation a manner toher'einaftertrset hforth. .The f condition responsive circuitlcon- .trolling means ,.11. illustrated in the drawing, sslrlpls'es what is commonly known as a `two-stagethermostat. In describing theoperation of the improved control apparatus itI will be assumedthat theV temperatureof the @96m orspase. being heated@ as sensed bv' the 1lifelllows- ,662 is such thatwth'e thermostat blade 63engages the fixed contact 62' but the blade 58 is disengaged from the contact 57. This disposition of the contacts results inthe actuator 9 being energized to hold` the onoft valve 7 open shown, and in the actuator 10 being deenergized to permit closureof the valve member 8f, for example bygravity.` Whenever the actuator 9 is ergized, kthe portion of vthe resistance Velement 55 ,betweenftheconductors 53 and 59' is also energized to causegeneration of a small output of heat providingl a low level of heat anticipation. Where no such low level anticipation is desired, however, the conductor 59' may be connected directly tothe conductor 53 or line wire Y,51s, so. that ,flapoxtin ofthe dement 55T .is energized duringvlovvmfuei now. With the valve member 8`f,c'losed;, the. Qnly, sas, which-can w-Yt the]biirn''` is filial `which can flowthrough the by-pass`49' topr'ovid'eU a low flame condition at theburner 6'. v

Inthe Lvent that the heat supplied by the burner `6 witha low ame yis greater than the heat loss` from the space being heated, thereby causing the temperature of .the space to increase and 'exceedafpredetermined high course, effects deene'rgization of the operator Y9 and the Yvalve member 7' is permittedto close, for examplefby gravity and fuel pressure, thereby shutting olf all fuel ow tothe burner 6o. v a Y Immediately upon yclosure of the valve member 7' the fuel pressure builds up inthe chamberrlo, thereby forcing `the diaphragm 28" and back-up plate 41', downwardly ,to force the Vhydraulic' fluid out ofthe chamber 39, and intothe chamber-itl through the aperture 36' and past check valve 38' and throughfthe aperture 37. Downward ,movement of the back-up plate 41 ;pull s the link 48' and the connected` end ofthe lever 45 downwardlyto pivot said lever in aclockwise direction and thereby lift the stern 47' land'valve ymember 8. The valve memberS isylifted'to an open positionwhich may be itszfull open position, ormay be a positionof vlesser opening affording suflicient fuelow for safe ignition: of the burner `6' when `the on-offvalve`7` issubsequently opened. The auxiliary actuating mechanismlZ holds the valvel member S in this raised V position as long as the fuel pressure inthe chamber 16 is vmaintained at full line pressure'by closure ofl the on-ofl valve member 7.

When the hydraulic fluid .is forced from the'chamber 39 into chamber 40', said fluid Vforces the diaphragm y25' and plate3l3 downwardly againstthe bias of `the spring 32. vThe vuid displaced from the chamber 31 by this diaphragm movement is vented into the outlet chamber 15 through the passage 35. t l

IAs the room v'or Aspace cools after extinguishment of the burner,flame, the bellows 66 ycontracts and moves the stem 71 and shoulder means 72. and 73 toward the left. A t a'predeter'mined,tempelalure the snap leaf 63T snaps into engagementwith the xedcontact 62', thereby energizingwthe;actuator 9 and Veffecting opening of theon-olt valveA 7j. Sincethe high-,low valve 8" i's 'already opened, sufli iieiit` ifeliiovv isivlilbl'e' tothe burner kfor ignitionlthereof'by suitable ignition means, for example by a constantly burning pilot burner 81', When theon-of valve member 7 is moved from closed to open position the fuel pressure within the chamber 16 drops, and the pressure within the chamber 15' rises luntil the pressures within saidlchambers are substantially equalized The auxiliary actuating mechanism 12 does not, however, permit the high-low valve member `8' to immediately move to closed position,said valvel member being held in an open position for a suflicient length of time to permit ignition of the burner 6'. eration occurs by virtue of the reed check valve 38 which prevents return Huid fiow through the aperture 36' when the pressures Within chambers and 16 approach equality. As a result, when the compression springs 32' forces the displaced hydraulic iiuid from the chamber 40 back into the chamber 39', Vsaid fiuid can flow through the restricted aperture 37' only, and ,a substantial period of time elapses before the diaphragm 28 and the plate 41 return to their normal positions shown in the drawing and permit the high-low valve member 8' to return to itsseat 18'. When the valve member 8 is seated, the fuel flow to the burner 6 is again limited to that which can ow through the bypass 49.

vIf a low flame at the burner 6' affords insufncient heat to ymaintain the proper room temperature, the bellows 66' continues to contract, and a a predetermined temperature the shoulder means 72 permits the snap leaf 58"'to snap into engagement with the xed contact 57. This causes energization of the actuator 10' and of en tire length of the resistance element 55. The high-low valve' member 8' is immediately opened by the energized actuator 10', and full capacity fuel liow to the burner 6' results. As the temperature of the room rises with the high burner flame, the bellows 66 expands, and a higher level of anticipation is provided by t-he relatively large amount of heat supplied from the full length of the anticipator 55. The bellows 66' expands and contracts thereafter, cycling the snap leaf 58' and thereby the highlow valve member S in accordance with normal fluctuations n temperature, i.e. temperatures below the prede# termined high lim-it temperature at which the snap leaf 63 is snapped out of engagement with the fixed contact 62 to close the on-of valve 7. However, at any time that the 'room temperature does reach the aforementioned high limit temperature, corresponding expansion of the bellows 66' effects disengagement of the snap leaf 63' from the contact 62', deenergizing the actuator 9', closure of the valve member 7', and shut-off of all fuel flow to the burner 6.

In the operation of the improved fuel control apparatus just described, the application of a separate automatical' ly applied level of anticipation for each of the levels of fuel ow avoids overshooting and short cycling of the heating system. 'Selection of the proper resistance ele- By virtue of the fact that the improvedfuel control apparatus of Figure 5 provides either high fuel flow, low fuel flow, or no fuel ow, quick warm-up of the heated space, for example, after night turn-down, is provided, since the burneroperates at full fuel capacity until the room temperature reaches a level calling forlow fuel flow.' The improved control apparatus of Figure 5 does not der`ate the heater, and safe ignition is insured with'- o'u'trequiring the temperature of the heated space to cool through vthe enti-re modulating range after `shut-off of the burner-L' OfA substantial commercial importance-is the fact that the improved' control apparatus of vFigure 5 is universally adaptable for use on any selected size heater up to the maximum size for which the vcontrol is rated. Itsadaptability is further enhanced by the `fact vthat it performs with equally high efficiency regardless of the type of gas burned in theselected heater, no changezor adjustment otherthanadjustment of the setting of the minimum yow adjustment screw 50" being required'fo'r adaptation of the control Yto a particular fuel." "i

The illustrated lforms ofthe invention havebeen selected for thepurpose 4of disclosure only andare not intended to define the'limits of the invention nor to con? fine the latter to any` particular use. Various rother changes and modifications =may be made without depart# ing from rthe spirit of the invention, andV allv of'such changes are vcontemplated as may come within the scope of the claims. v y

What is claimed as the invention is: y y1. Apparatus for controlling the o'w ,of` fluid fuel, comprising: `f A'rst flow-,controlling member having con'- dition' responsive actuating means for actuating said flowcontrolling member between a minimum', stable flame flow-permitting position and an"l increased flow-permitting ignition position in response to changes inthe condition; a'second flow-controlling member movable' to flow-pre'- venting position in response to an extreme in said con'- dition calling fora lesser ow than 'said'minimumg jand means for insuring safe ignition of the' fuel including means for actuating 'Said rst flow-controlling member to said ignition position in response to movement of said second flow-controlling member to now-preventing posi'- tion.

2. Apparatus for controlling the flow of lluidfuel, comprising: A first flow-cont`rolling member having condition responsive' actuating means for actuating said owi controlling memberbetween av minimum stable flame flow-permitting position and an increasedow-permitting ignition position in'resp'onse to changes in the condition; a second flow-controlling member movable toliow-preventing position in response to an extreme in said condition'calling for a lesser 'ow than saidl minimum; and means for insuring safe ignition of the fuel, including means for actuatngsaid first now-,controlling member to said vignition position in response to movement of said second 'flow-controlling member to' flow-preventing position', and means for holding said'v first now-controlling member in an increased owpermitting position fora predetermined period'aft'er subsequentmoveme'nt of the secondl owcontrolling member tofow-permitting'pos'ition.

fApparatus for controlling the flow of liuid fuel comprising; AV firstV flow-controlling member having condition responsive actuating means'for actuating said flow'- controllingl member ,betweenV a minimum stable' llame flow-permitting position and an increased now-permitting vignition position in response Ato normal lfluctuations in the condition; a second now-,controlling member, condi,- vtion responsive'ine'ans for actuating said second flow? controlling member operableyto effect movement of Isaid member to 'a flow-preventing position in' response to an extreme in the condition calling for lesser flow thanl said minimum; means responsive to movement of the second Howl-Controlling member to flow-preventing position for moving said rs't ow-controlling member to said ignition position; and means for holding said first flow-controlling member in an increased now-permitting positionf fol-"a predetermined period after movementl of 'said second flow-controlling member to flow-permitting'. position;

4. Apparatus for controlling lthe ow of fiuid\fuel,.com` prising: A flow-controllingl member biased toward `a minimumow-permitting position; condition responsive actuating mechanism for actuating lsaid How-controlling member between said minimum flow-permitting position and an increased flow-permitting ignition position against said bias in response to changes in the condition; an on'- off valve; la diaphragm operatively connected to said flowcontrolling member and having one side exposedl to the fluid pressure of the fuel upstream from the on-off valve and havingits other side exposed to the fluid pressure of the fuel downstream from the on-of valve, whereby upon closure of the latter valve the uid pressure upstream .lJ; .1L .iloig.,i '..i..y.,t n. j aphrasm. andrmoves the .ovvr ignition position against-Seid onseof. said condition responeractuetinggmeehanism tothe ambientoondtion, the tyujid-tpressureon4 th'eopposite sidesgof, s aid diaphragm beingzequalizedfto; release. .said flow-.controlling member tot.. erncontrotot saidtcondition. resposivetaetuatiog mechanismryvhen s'adl onoifvalveiiis opened;j and time delayxiiechanismconnected tosaid ow-controflling membei'andaoperableztoeretard.thenmovetrlemf the .latter 1ro toward said minimum liow-permittingpositionunder said bias, when frieasedbyfopening oi .saidon-Qi va1ve,lwhere by ysaidv dow-.controlling memberris disposed .din ignition position ,whenever saidineoff valve isopened, `and yafter a time del'aygxis 'returnedto thetcontrol of said condition 15 responsive: actuatingrnehanism.-y t,

. -S'a-JipparatusJ for controlling ghe; how/df guid `fuel, comprising.: '1 Atovv-.cotrolling member biased toward a dtdi'murldow-permitting..lpositio'n; condition. ,resnoxleive etuatingttrnec'lanism.. having annui-directional.. Sellerable 20 force'.transiitting.connection:1 it idMow-,controlling membenffrrmodulating thesiatt, i against, lsaid* bias i be- .tweensaidzminimumlowepermittjng1 position and i i creas'ed'.:tiowepeimitting,ignition, position inmrespohseuto i. e hangesintthes condition'tlan Qon-oft' Lvalge; Land `:auxiliary 25 .'actiatingitmeans directlyeconneotedgto-said i A I V ling-member and responsiverto QLQSLJI@ Of. dldioll 'fifi/.allie tonni/reautsaid. conditien...r.esponsive actuating mechavniemandposition saidfowteentrelling tion position-irrespective'ofithe esponsegorf Jai fresponsiveemecha'nism;to theetamlgient condf'ionyaknd to -releasei` 'saidfiowgcoiitrollingnmernber to the: control of member andfoperableto retard the, move tewardsaidminimum naw-permitting.-.posmenfuersaid bias when releasedby .openingLsaidpn-off valve, vwhereby said .now-controlling' memben isudisposedi 1in Aigni tionffpo-s.ii

Itime delay;is..freturned.toLthe; ,contro1'of said condition freponsivexactuatingmechanism M. lzfAppar'atus'ffor@controllingtthe ow of iinidmfuel, vcc'mprising:1,1A.dow-controllingl memberga temperature r4responsiveiactilating,mechanism for l.actuating `said tiow- 45 controlling?.iinembernbtween ,.a. minimum Stable`VI `dame 4iivv-perrilitting` position a'nd fan increased flow-permitting Aignition positiony iiresponse .to normal. flufiutolls til! .tem- -peratureg= an .fon-.olf valyenapparatns incilnd'ing an electrq- 'responsivooperator foie-said o'n-ojivalve connected. in 50 circuit:iwithmasourcenoietectrie. 1 nergya ,a .foireditreontml1ing..fde,vic`e.y lint Seide OperaiQList z I energization of said operator whereby;4 Ythe llawttA lvies open, eeidfereu'f responsiv 119;@ epredeterm energize.- .Saidsiopetetot fo-.elQSet Seid Qn fooi 4 ttglltlsnd T drop. attempt-fe etgiee ytmovosaidflow controllingl ni'efmbefr to ksaid ignitionv posiftionein response.I to .el @dreef ...seid-edreff .valve` irree'peetive;of;.ltheresponse.A Afjlie.,temperature responsive a'ctat- 55 ing mechanism to the ambient Ate rature.

e7 Apparatus tfor. controlling -theeovvsof-ud xfuel, eomprisingi. A. now-,controlling member biased tov/ard. e first positionan actuatingrmechanism for modulating said tarsecoiidsposition,againsgfsaid bias and `in `responseuto dition;` an ton-off valve;

.ipa first. and .Seeeed .eenttolf members .-mevebte. t9 first wir, `i= "it \..:e mi mg; wf,- i: .liegedevee in eeidnere'tor eife'uii' energization of saidoperatorwhereby thei te' ho s on-oi valve open, .saidI `circuit-eointrolling device b e'- sponsivefto a` predetermined extreme conditionto ,dee'n. ergize said loperzvitor..and, close'lfsaid o'n-'oil valve,O s d circuit-controlling"device being responsive to Vsubsequent moderation of the condition `to belowlsaidfextreme conldition toreenergize said operator` and opensaid on-otf valve;v a diaphragm connected ..to.said .dow-controlling member and having one side exposed tokt'heuid pressnre of the.f1.1e.1dpeffeemzffemthe on-ei velve .end having its othertside'exposed to thevfiiiidpressure on the downstream sidenof the on-oiyalve, whereby. nponciostireof` thelateivalve the fluid `pressure upstream. .therefrom "actualtes said diaphragm .end moves/the.doveeedtsollng inetd en to said` second position against; said{bliesnirrespectivet,ofe response.oftheeondition .respodeiveeetdetirie meehe l. m tothe. ambient. Condition., .the fldidrpressdreon theoppo Sitesideeof -thesed-diaphreem ,being equelilfedtotl lease the .ovvreontrollinemetber to the eojtrol `.of d condition responsive.- aetuetins meeheniemfvvhede ...edoi valve is opened; and time delay mechanism conneftxed to saidgigiovili-controllingk memberand operable to ret `d the, movement .of Ythe. iletterettolvverd. :Seid fe; oslttol under said. bias when .released bveopening .ofteeld .i1-.eff valve; whereby said -iow-controiliing member isl 3d" posed in said secondfposition whenever said n-oi; alvegis opened, and after atime delay, is. rl eturnedto thecontrol of thecondition responsive actuatinggrriechanism.lv

8. Apparatus for controlling thegilow ofriluid ufpei, comprising: r A flow-controlling gmember .biased toward a minimum' flow position;v atemperatnre reSpQDSYQzRG/tllv atingmechanism having anni-directional separable force transmitting? connection t ;With',sai'd Uovy-,co ntvrollingl memberfor` modulating said flow-controlling ymemberagainst said4 bias between said minimnmuowpositionandari increased'` ow-permittinggignition position in response -,to normal uctuationsin temperature; an on-oi, vaivepap; p'aratus including an electro-responsivev operator Vforsaid on-otr' valveconnected in *circuitjwith -a source of electrical'r energy; a thermostatin Ysaid operator cincuitgnormallvoadsing. energization .of .Said operatorV whereby the latter. holdsthe onoifvalve open, saidg'thermostat being responsive vtoa Ypredeterminedhigh temperature tv ideenergize said ,joperator and closesaid `onolH valve, said thermostat also bein'g responsive yto a subsequentdrop in temperature to below `said predetermined high temperatureA tojree'nergize said ,operator` Aand open said A(1n-'off valve; endiephragm connected to. .Said ;oW.-.eo11troll.1.g member. for movement directly and .Continuously these- .wifhnseid-diephragm .having onetside exposed to. .the fluid theuid pressureon threopposite sides of thesaid diphragm being equalized `to release the vflow-controlliiifg memberwto they controlrof said temperature responsive actuating mechanismuwhen said yron-.off valve is opened;

and uni-directional time delay mechanism connected to said flow-controlling member and operable to retard .the movement of` the latter toward said minimum positionnunder said bias when.` released-.by ,openingof Asaid on-oi valve, whereby said now-controlling member` is disposed in said ignition position whenever said on-oi "dow-controllingmembenb tween lsaid rst position. and 70 `valve is opened, and y after la time delay, isreturncd to the control of the temperature responsive actuating mechanism. i 4 Y i. i l i 9. Apparatus forcontrolling the fiovvV of :f1uid,4comp and second controlling positions,Y condition. responsive means for actuating said first control member from its first `to its ysecond controlling position in response to changes' inthe condition, and actuating means independent of.said condition responsive actuating means and of which said second control member is independent for overcalling said condition responsive actuating means and actuating said first control member to its first controlling position in response to disposition of said second control member in its` second controlling position irrespective of the response of said condition responsive actuating means to the ambient condition.

10.l Apparatus for controlling the fiow of fiuid, comprising av first control member biased to a first controlling position and movable to a second controlling position, a second control member movable to first and second controlling positions, condition responsive means for actuating' said first control member from its first to its second controlling position in response to changes in the condition, means for overcalling said condition responsive actuating means and actuating said first control member to its -first controlling position against its bias in response to movement of said second control member to its second controlling yposition irrespective of the response of said condition responsive actuating means to the ambient condition, lsaid overcalling means releasing vsaid first control ymember for movementrtoward its first controlling position'under its biasin response to movement of said second lcontrolmember to its first controlling position, and time delay means operableto retard movement of said first control member fromits second toward its'first controlling position. f I I 1"1. Apparatus for controlling the fiow offiuid,` comprising first and second control' members movable'to first and second 'controllingjpositiona condition responsive means fof-actuating said first control member from its first to itsv secondcontrolling position in response vto changes Vin -the condition, -an electroresponsive operator for said second control member connected in circuit with a source of electric energy, a circuit-'controlling device in said operator circuit controlling thenenergization of said operator-'and thereby the'position of said second control member; and 'actuating means independent of said condition responsive'actuating means for overcalling the later and'fm'oving saidfirst control member to its vfirst controllingy position in response todisposition lof said second controlmember in its second'controlling position irrespec tiveof the'response ofsaidfconditon responsive actuating rmeans to the ambient condition. Y l2; Apparatus for controlling the flow of fiuid, comprising first and second control vmembers movable to first and second controlling positions, condition responsive means-for actuating said first control member from its first to its second controlling position in response to normal* fijuctuations in 'the condition, a'n-electroresponsive'` operator' for said second control vmember connected in circuit with a source ofelectric energy, a condition responsive circuit'controlling device in said operator circuit controlling the energization of said operator and `t l 1e reby the position of said second control member, said .circuit controlling device normally effecting disposition off'said second control member in its first controlling f position and being responsive 'to anextreme in the condition to effect movement of said control member to `its secondr controlling"position, and'means independent of said condition responsive actuating means for overcalliug the latter and actuating saidfirst control member toits first kcontrolling position in" response to dispositionv of said second controlmemberfin its second controlling positronrirrespective' of the response of` said condition responsive actuating'means'to the ambient condition. 13. Apparatus for controlling the flow of fiuid, comprising first and second control members-movable to first and second controlling positions,' condition responsive means for actuating said first control member from its to its second controlling'position in response to nortrol member in its first controlling positionfand beingy positioned for actuation by said condition responsive actuating mechanism in response to an extreme condition to effect movement of said second control v member to its second controlling position. 1 r i 14. Apparatus for controllingfthe-iflow offuidrcomprising first and second control,` rnembersm`ovable to firstv and second controllingpositions, condition responsive means for actuating said firsty control member from its first to its second controlling -positionin response to normal fluctuations in' the condition, an electroresponsive operator for said second control member connected 4in circuit with a source of electric energy, a circuit-control'- ling 'devicefin said operator circuit controlling atheenergitzation 'of'said operator and thereby the'position of said second control member, said` circuit-controlling.device normally effecting disposition of said second control member in fitsffirst controlling position andbeingpositioned for actuation by -said `conditionfresponsive A'actuating mechanism in response to anextremeconditionto etect movement of said second control member: toits second controlling position, and 'means independent of said condition responsive actuating means for overcalling the lat.- ter and moving-said first control member `to vits first controlling position in l"response to disposition'` of` said second control member in its second controlling position irrespective ofthe response of said condition responsive actuating means to the ambient condition:v e

prising first and second control members each movable to controlling positions,- condition respousve'means for actuating said first control, memberfbetween'afirst and second controlling position while holding saidsecond control member in 4a first controlling position during norvmal fiuctuations'inthe condition, said actuating means beingresponsive to an eirtreme'in-Ithe` condition to effect movement of said second controlrmember to asecond controlling position, and auxiliaryy actuating means for taking over control; of saidfirst controlmember and actuating the latter to its said first controlling position in response to movement iof said second control member to its'second'controlling position, saidauxiliary actuating means releasing said first control memberzfor actuation by said condition` responsive actuatingy means in response to mvementfof said second control .member to its first controllingl position, land-time delay'means vopersecond control member'to its second controlling position irrespective of the response of said to the ambient condition@L f 1 t 17. Apparatus for controlling the* flow of fluid, comprisingl a first main fueltiow controlfmember movable betweena minimum flow-permitting and a maximum flowpermitting controlling positions, a second'main fuel flow control member movable between flow-preventing and flow-permitting positions; condition responsive means -fo'r lfirst actuating means actuating said firstv control member from its minimum flow-permitting to its maximum flow-permitting controlling position iinresponse gto changes intthe condition, `Vand actuating ln1`e`ans:-r`or overcallingrsaid :condition responsive :actuating meanstandiactuating said 1lirst control member to its vmaximum flow-permitting controlling position responsive fto disposition of `saidysecond control member in itsfloW-preventing position irrespective of the response of vsaid condition responsive actuating means to theaml'bient condition. l

18. AIn 'a valve'structure: means ,defining an elongated chamber having in communication with its opposite ends Aa main `inlet andan outlet; ya pair of valves arranged in vseries in said` chamber so that uidmust pass through -bothrof'the valves `from -said main inlet` to said outlet, `one of Vthe valves being yadjacent the main-,inlet endv fof the chamber andithe other adjacent the outlet end; said chamber." having intermediate s aidfyalves a restricted inlet through `whichzuid ,canpass when said one of the valves is closed and said other of the valves is open; means,` including. means movablegradually'in response to variation ofra ,controlling condition, for actuating the valves yin such Lsequence, while said condition is varying in ra given sense, that said one ofthe `valvesiisclosed before the other Aof thepvalves is closed, and means arranged so that `opening Imovement vis imparted to said one *.valve before openingmovement ,is impartedtopsaid other valve in response to=variation of said condition in an opposite sense. p Y

19. In a :valverstructure: qmeans defining an elongated chamber havingyin Acommunication with its opposite ends Aa main inlet` and an;outlet; a pair of valves arranged in ,series int-said chamber so that uid must pass through both of zthe -valves -from said main inlet to `said outlet, oneffof lthenvalves being adjacent the main-inlet end of the chamber and being of the type :which comprises a vclosurepositionableirelative to a valve seatso as to vary and toobstruct dow, the other of the valves being adjacent the outlettendofgthe chamber and-being of the on-olf y;type;`said chamber having intermediate said valves a re- .fstrictedyjnlet throughwhich fluid can pass Vwhen said one of thelvalvesiis I,closed and-said other of the valves is open; '.means, ;including means movable gradually in response to variation of a controlling condition, for actuatingithe'valves 4infsuch sequence, while said condition is varyingfinyaygivensense, that said one of the valves is closed beforesaid other of the'valves is closed, and means arrangedfiso thatopening movement is imparted tosaid :one valvegbefore'wopening movement is imparted to said :other valvefiin responsegtovariation of said condition :in-anfoppositegsense.

20. 'Ima valve structurezffa-casinghaving an inlet-and .san outletand archambergtherebetween; an inlet valve `controlling fflow: from said i inlet ,to said ,chamber and Vanioutletu-valveicontrolling ilowfrorn the chamber to `:saidoutletyimeans,including means responsive to varia- ,.'tion'of aicontrolling,.condition;for actuatingsaid valves arranged so thatwllenjsaid condition varies inra given isensethe outletfvalve is openedbefore movement of the ginletrvalvefinfopening direction, `and the inlet -valve is closedigbefyoreatheoutletivalve is closed when theconditionefvariesinftheoppositesenseasaid chamber having a f frestricted `opening 'leading to said inlet and by-passing the yinleti-ivalveo fthatnwhen :the outlet valve `is open and f theinlet valyegisjfclosed fluid` can ow from said inlet rftof,saidgoutletthroughi the. chamberV and said restricted t. :openingpmeans forisupplyirlgV pressure iluid to. said inlet;

u..and,a moton, operated inrresponse to the change of fluid pressureginr s aidechamber occurring upon closing and --uponoreopening-of lsaid outlet valve, for actuating said inletfvalveindependently.ofvsaidactuating means and of @the, outletyaluewsaid motor being arranged to elect opening orfgtlrerinlet valve .upon closing ofthe outlet valve,

and delayed closing of theinlet valve upon reopening mof.. the ,outlet .,:valyea said., means Vfor actuating `said valves grail;

p anged so thatitiscapablepof actuating the inlet ,yalyeto ppernposltiongragainst .theqforce Vof saidunotor. Y,

18 2l. Ina valve structure: ya casing having an inlet and an outlet and Ia chamber therebetween; inlet valve means 4controlling flow from said inlet to said chamber and outlet valve means controlling ow from the chamber to said outlet; means, including means responsive to varia- .ing by-passing said other valve means so that when said one ,valve means is open and said other valve means is closedy fluid can flow from said inletto said outlet through the chamber and said restricted opening; means for supplying pressure fluid to said inlet; and a motor, operated in response to the change of fluid pressurein said charnber occurring upon closingand uponreopening of said one valve means, for actuating said other Valve means independently of said actuating means and of said one valve means, said motor being arranged to effect opening of saidother valve means upon closing of said one valve means, and delayed closing of said other valve means upon reopening of said one valve means; said means for actuating said valve means beingarranged so that it is capable of actuating said other valve means to open positionagainst the force of said motor.

22. VApparatus for controlling the flow of liuid comprising first and second control members movable to first and second controllingpositions, rst means for sequentially actuating said control members to their second ycontrolling positions in response to a predetermined changedna-given condition,land second actuating means independent ofsaid condition responsive rst actuating means `for moving said irst control member to its iirst controlling position responsive to movement of said second `control member to its second controlling position irrespective of the response of said rst actuating means to said given condition.

23. Apparatus for controllingthe flow of fluid comprising lfirst and second control members movable to first and second controlling positions, rst means for sequentially actuating said first control member to its second controlling position and then said second control member to its second controlling position in response to a predetermined change in a given condition, and means for delaying return movement of said rst control member toward its second position following movement of said second control member to its rst position and second actuating means independent of said condition responsive lirst actuating means for moving said first control member to its rst controlling position responsive to movement of said second control member to its second controlling position irrespective of the response of said rst actuating means to said given condition.

24. Apparatus for controlling the flow of lluid comprisinga modulator valve and an on-oi valve each movabiletoV closed and open positions, lirst actuating means for seouentially modulating said modulator valve to closed position and then moving said on-off valve to closed position in response to a predetermined change in temperature, and second actuating means independent of said first actuating means for moving said modulator valve .to `open position responsive to movement of said on-ol valve to closed position irrespective of the Vresponse of saidfirst actuating means to said temperature.V

25.,.Apparatus for controlling `the flow of fluid comprising a modulator valve and an on-of valve each movable to closed and open positions, rst actuating means forsequentially modulating said modulator valve to closed position and then moving said on-of valve to closed position in response to a predetermined change in temperature, second actuating means independent of said rst .actuating means for moving said modulator valve to open defining a restricted bypass around one of said valves through which fluid can pass when said one valve is closed and the other valve is open, means, including means movable gradually in response to variation of a controlling condition, for actuating the valves in such sequence,

while said condition is varying in a given sense, that said 15 one valve is closed before said other valve is closed, and means arranged so that said one valve is opened before said other valve is opened.

27. In a valve structure: means defining a chamber having an inlet and an outlet, a pair of valves arranged ,20

in series in said chamber so that fiuid must pass through both of the valves from said inlet to said outlet, one of said valves being of the type which comprises a closure positionable relative to a valve seat so as to Vary and to obstruct flow, the other of the valves being of the on-of type, means defining a restricted bypass around said one valve through which fiuid can pass when said one valve is closed and the other valve is open, means, including means movable gradually in response to variation of ,ar controlling condition, for actuating the valves in such se-i'" quence, While said condition is varying in a given sense, that said one valve is closed before said other valve is closed, and means arranged so that said one valve is opened before said other valve is opened in response to,

variation of said condition in an opposite sense.

28. In a valve structure, means defining a chamber having an inlet and an outlet, a pair of valves arranged in series in said` chamber so that fiuid must pass through both of the valves from said inlet to said outlet, means defining a restricted bypass around one of said valves through which uid can pass when said one valve is closed and the other valve is open, means, including means movable gradually in response to variation of'a controlling condition, for actuating the valves inl such sequence, while said condition is varying in a given 145 sense, that said one valve is closed before said other valve is closed, and means arranged so that opening movement is imparted to said one valve before opening movement is imparted to said other Valve.

29. In a valve structure: means defining a chamber.-

having an inlet and an outlet, a pair of valves arranged in series in said chamber so that fiuid must pass through both of the valves from said inlet to said outlet, one of said valves being of the type which comprises a closure positionable relative to a valve seat so as to vary and 'l 55 to obstruct flow, the other of the valves being of the ori-off type, means defining a restricted bypass around said one valve through which fluid can pass when said one valve is closed and the other valve is open, means,

including means movable gradually in response tovariationrof a controlling condition, for actuating the valves 1n such sequence, While said condition is varying in a given sense, that said one valve is closed before said other valve is closed, and means arranged so that opening movement is imparted to said one valve before open` 65 ing movement is imparted to said other valve in response to variation of said condition in an opposite sense.

30. Apparatus for controlling the fiow of fluid fuel, comprising: A control member movable to first and second controlling positions, condition responsive means v comprising an electroresponsive actuator for actuating said control member between its first to its second controlling positions in response to changes in the condition, an on-off valve, and fiuid pressure responsive actuating means operatively connected to said control member and exposed to the pressure 'of the fuelupstream of said on-off valve whereby on closure of the said valve .said fiuid -pressure responsive means responds to theincrease in the fluid pressure upstreamrom said valve and actuates said control member toward its'said second position, said pressure responsive actuating means also being responsive to a drop in said fluid pressure Von opening of said valve to release said control member, said pressure responsive means including time delay means operable to retard said release. p

3l. Apparatus for controlling the flow of fiuid comprising first and second control members movable to first and second controlling positions, first condition responsive electrically powered means for actuating said first control member between its first and its second controlling positions in response to changes in condition, and second actuating means responsive to movement of said said second control member to its first controlling position for overcalling said first actuating means and insuring disposition of said first control member in its second controlling position. wheneverr said second control member is in its first controlling position.

32. 4Apparatus for controlling the fiow of fluid, lcomprising rst and second control members movable to first and second controlling positions, condition responsive means including an electroresponsive actuator for actuating said first, control member between its first and its second controlling positions-in response to changes in the condition, an 'electroresponsive operator for said second control member, and means for overcalling said condition responsive means and` moving-said first control Y member toward its second controlling position in response to-movement of said second control member to its first controlling position.

33. Apparatus for controlling the Vflow of fluid ycornprising a first control member biased toward a first controlling position and movable toward a secondcontrolling position, a second control member movable between first and second controlling positions,condition responsive electrically/.powered means for controllingthe position of said first control member, said' means comprising first actuating means operable when energized to position said first control member in said second controlling position and when' deenergized to position said member in said first controlling position, second actuating means overcalling said first actuating means and moving said firstcontrol membertoward its second controlling position in response to movement of said second control member to its first controlling position,`V said second actuating means releasing said first control member for movement toward its first controlling position by said first actuating means when deenergized in response to movement of said second control member to its second controlling position, and time delay means operable to retard movement of said first control member from its second toward its first controlling position.l

34. Apparatus for controlling the fiow of fluid, comprising first and second control members each movable to controlling positions, condition responsive means including an electroresponsive actuator for each of said control members for actuating said first control member between first and second controlling positions while retaining said second control member in a one controlling position in response to normal fluctuations in the condition, said means being responsive to an extreme n the condition to effect movementv of said second control member to another controlling position, and auxiliary actuating means for taking over the control of said first control member and actuating the latter toward its second controlling position in response lto movement of said second control member to its said other controlling position.

35. Apparatus for controlling the flow of uid comprising first and second control members eachmovable to controlling positions, condition responsive means infammes? "il'u'ding v'an felectrorejs'ponsive Aactuator for ,each of said control members' for .actuating said first control `member A `between laJ first and a secoridA controlling position while A retaining said second controlLmember ima second controlling position'in response to normal fluctuations Yin Vvthe condition, said means being responsive'to anex- "treme in the condition to effect movementl of 'said second control member toa first'` controlling `position,,auxiliary actuating means for 'taking over 'the control of: said. first t control member and actuating'ithe f latter toward'its trst controlling position in response to movement of` said ysecondcontrol member to its 'firstjcontrollingposition, said auxiliary actuating meansreleasing said first control limember in response to movement-of jsaidsecondcontrol dof saidrst controlling member -between first and second controlling positions in response to normal 4fiuctuationsrin *".the condition,second'electroresponsive actuating means t Afor said. second `control member, a second condition Vre- :sponsive circuit controlling device connected in circuit 'with said second actuating means and a source of electric s `energyffort controlling energization `:off said `second actuatingmeans and therebytheposition of said second control member, said'isecond circuitfcontrollingdevice normally effecting disposition of said secondcontrol member in its second controllinglpositionsandbeing operable` in responseto an extreme in the condition-to effect movement of said second control member to its first controlling position, and ,means for overcallingfsaid first'iactuating ,zmeans and moving said firsttcontrolirnember toward its @second con-trolling position in response to movement of` the second control member to its first;c'ontrolling position.

i37. Apparatus for controlling the iiow ofy fiui'd,.comy t prising first and` second control members ,.movable to first and second controlling-positions, `first electrorespon?,v

siveactuating means for said rst-control'tfmember, a first temperature responsive circuit controlling device isive actuator'sfor :controllirrgth eiierg'ization thereof "and .effectingactuation of"said""firstrcontrol member between a` frst' andi-a1second'icontrolling lposition `while retainingsaid secondontrlmfemberlin one controlling position during knormal fluctuationsein" the condition, said circuit controllingmeansbeingresponsive to an extreme in the'condition'to effect movementof?V said second control member to another `controllingposition, and auxiliary actuatingmeans for actuating saidffirst'control member ltoward its second controlling position in response to movement of said second Vcontrol memberto its said other controlling position. f

39. Apparatus foo-controlling thel iiow of fluid, com- -prising*'first and second contrlmernbers yeach movable to controlling positions anfelectrores'p'onsive actuator for each of said controlmenibersinfcircuitwith a source of electric energy, a two-stageft'hermostat"having contacts 'in circuit with said-electroresponsivei actuators for controlling the energization thereof and reffecting actuation of said first control member between affirst and a second controlling positionwhile retaining said second control member'in one controllingjposition "during normal tem- -.peraturefiuctuations, said thermostat being responsive to an extreme temperature to e'fjec't movement of said second `control member to anotherfcontrolling position, and

auxiliary actuating means for-actuating said first control member toward itssecondcontrolling position in response to movement of sai'dfsecond'control:member to said other controlling position. o Y o t 'Y V40. Apparatus for controlling vthe fiow of fiuid, cornprising rst-and secondl controlmembers each movable cto controlling positions, Lanfelectroresponsive actuator Vfor eachfofwsaid controllmembers'in circuit 'with a source vof electric energyga two-'stage-conditiontresponsive circuit @controlling devicehavingvcontactssin circuit with said electroresponsive .actuators foriefiectingr-actuation of said first control member fbetween aJfirstfand va second con- .ztrollingtposition' while 'effecting 4retention of said second `control member inonezcontrol'ling position during normal in circuit with said electroresponsive actuating means and with a source of electric energy for controlling the energization of said actuating means and effecting movement of said first controlling member between said first and second controlling positions in response to normal temperature fluctuations, second electroresponsive actuat- :ing means for said second control member, a second temperature responsive circuit controlling device connected :in circuit with said second actuating means and a source of electric energy for controlling energization of said :second actuating means and thereby the position of said fsecond control member, said second circuit controlling Idevice normally effecting disposition of said second con- :trol member in its second controlling position and being roperable in response to an extreme temperature to effect movement of said second control member to its first controlling position, and means for overcalling said first :actuating means and insuring disposition of said first control member in its first controlling position in response to movement of the second control member to its first controlling position irrespective of the response of the rs-t circuit controlling device to the ambient temperature.

38. Apparatus for controlling the flow of fluid, comprising first and second control members each movable to controlling positions, an electroresponsive actuator for each of said control members in circuit with a source of electric energy, condition responsive circuit controlling means having contacts in circuit with said electroresponfluctuations inthe condition, :said circuitcontrolling device` being=responsive to anfextreme` in the condition to effect movement of said-second control memberto another controlling position, -auxiliary,actuating` means for actuating .said=firstlcontrol zimemberatoward `its second controlling positionrin.responseltomovement ofzsaid second control `member to itssaid'.otherccontrolling position, said auxiliary actuating means releasing said first control member in response to movement of said second control member to its said one controlling position, and time delay means operable to retard said release.

4l. Apparatus for controlling the fiow of fluid, comprising first and second control members each movable to controlling positions, an electroresponsive actuator for each of said control members lin circuit with a source of electric energy, a two-stage thermostat having contacts in circuit with said electroresponsive actuators for effecting actuation of said first control member between a first and a second controlling position while effecting retention of said second control member in one controlling position during normal temperature fluctuations, said thermostat being responsive to an extreme temperature to effect movement of said -second control member to another controlling position, auxiliary actuating means for actuating said first control member toward its second controlling position in response to movement of said second control member to its said other controlling position, said auxiliary yactuating means releasing said rst control member in response to movement of said second control member to its one controlling position, and time delay means operable to retard said release.

42. Apparatus for controlling the ow of iiuid fuel comprising, a high-low valve biased to low fuel flow permitting position and movable to higfh fuel flow permitting position, an on-off valve, first electroresponsive actuating means for controlling the positioning of said low positions in response to changes in the condition, and

second actuating means responsive to closure of said onoff valve for overcalling said rst actuating means and insuring disposition of said high-low valve in said high position whenever Ysaid on-oif valve is closed.

43. Apparatus for controlling the `llow of fluid `fuel comprising, a high-low valve having a low fuel flowpermitting position and movable to high fuel How-permitting position, an on-ol valve, rst electroresponsive actuating means for controlling the positioning of said high-low valve, saidv actuating means being operable when energized to position said high-low valve in high position and when deenergized to position said valve in low position, condition responsivecircuit controlling means having contacts in circuit with a source of electric energy and with said electroresponsve actuating means for controlling the energzation of the latter and effecting movement of said high-low valve between said high and low positions in response to changes in the condition, and second actuating means responsive to closure of said on-oi valve for overcalling said first actuating means and insuring disposition of said` high-low valve in said high position whenever said on-oi valve is closed, and means retarding movement of lsaid high-low valve toward said low position by said rst actuating means when deenergized on opening of said on-oif valve after closure thereof.

44. Apparatus for controlling flow of uid, comprising first control means having a .condition responsive electroresponsive operator and a first control member movable thereby between irst to second controlling positions in response to changesY in condition, second control means including a second control member movable between first and second controlling positions, actuating means responsive to movement of said second control member to its lirst controlling position for overcalling said rst control means and insuring disposition of said irst control member in its second controlling position whenever said second control member is in its rst controlling position.

Y ##124 45. In a valve structure, means dening a chamber having an inlet land an outlet, a high-low valve andan lon-off valve arranged in series in said chambenvarreffstricted by-pass around said high-low valve permitting va :low rate of fluidow throughjs'aid chamber from said l Ainlet to said outlet when said high-low valve,is .closed Y .and said on-oif valve is open, electroresponsive operator I means for said valves, condition responsivecontrol means 'orsaid operator means causing the latter to actuate the valves `in such sequence, while the condition is varying in a given sense, that said high-low valve is closed before the on-offy valve is closed, and means operatively associated with said high-low valve for opening the latter lbefore said on-of valve can be opened by said operator means in response to variation of said condition in an opposite sense. 1 v

46. In a valve stnlcture,. means delining `a chamber 1having an inlet and an outlet, a high-low valve and an ori-oli valve arranged in series in said chamber, a restricted by-pass around ksaid high-low valve permitting a low rate of uidllow through said chamber from said inlet to said outlet when'l said high-low valve is closed and said on-of valve is open, electroresponsive operator means for said valves, condition responsive control means for said operator means causing the latter to actuate the valves in such sequence, while the condition is varying in a given sense, that said high-low valve is closed before the on-oftl valve is closed, means operatively associated with said high-low valve for opening the latter before said on-of valve can be opened by said operator means. in response to a variation in said condition in an opposite sense, and means for retarding closure of said high-low valve following opening of said on-olc valve.

References Cited in the le of this patent UNITED STATES PATENTS A;

Douglas Oct. 17,

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