US2909218A

US2909218A - Fuel flow control device

Info

Publication number: US2909218A
Application number: US579851A
Authority: US
Inventors: Russell B Matthews
Original assignee: Baso Inc
Current assignee: Baso Inc
Priority date: 1956-04-23
Filing date: 1956-04-23
Publication date: 1959-10-20
Anticipated expiration: 1976-10-20

Description

Oct. 20, 1959 R. B. MATTHEWS 2,909,218

FUEL FLOW CONTROL DEVICE Filed April 23, 1956 2 Sheets-Sheet 1 FIG.I.

4 a? I 35 I 17 I8 I0 I I I4 5 I 23 a 16 I l3 8 5 I02 I I03 29 I I 27 I I I 66 64 65 n |27 I l I INVENTOR. RUSSELL B. MATTHEWS 0a. 20, 1959 R. B. MATTHEWS 2,909,218

FUEL FLOW CONTROL DEVICE Filed April 23. 1956 2 Sheets-Sheet 2 INVENTOR. RUSSELL B. MATTHEWS ATTORNEYS United Statesv Patent FUEL FLOW CONTROL DEVICE Russell B. Matthews, wauwatosa, Wis., assignor to Baso Inc., Milwaukee, Wis., a corporation of Wisconsin Application April 23, 1956, Serial No. 579,851

17 Claims. (31. 158123): a

This invention relates to improvements in fuel flow control devices, and more particularly to thermoelectrically powered high-low fuel control valves. Experience has shown that modulation of theheat supplied to a given'space from fluid fuelburning heating" apparatus in accordance with the heat loss fromsaid space can be efiectively provided by flow control devices which are operable to permit fuel flow to said apparatus at either a high or a low rate depending upon the temperature Within said space, and which are operable .toshut off all fuel flow to the apparatus when the temperature within the space reaches a predetermined level." In control devices of this type, the low rate of flow permitted there'- by must not be less than the minimum at which .the bulner can safely burn the fuel, and it is also necessary that for safe initial ignition of the fuel at the burner the high rate of flow be delivered thereto, the low rate, of

course, being unsafe for such ignition purposes.

While it is desirable to provide the aforementioned high-low type of control in a system which is self powered, i.e. a system which is powered by current derived, for

example, from a thermoelectric generator subject to? the heat of burning fuel at a pilot burner, the work required to actuate a main fuel valve to open positionagainstv the line pressure takes sucha large percentage of the power available from the thermoelectric generator when. such a valve is actuated by a direct acting operator, that the thermostat leads must be kept relatively short in order to maintain the circuit resistance sufiiciently low to permit thermoelectric current to be delivered to the operator in sufficient quantities for actuation of the main fuel valve.

With the above in mind, it is a general. object of the present invention to provide an improved high-low fuel' flow control device having a high capacity valve operable when open to permit delivery of fuel to the main burner at a relatively high rate, and having a low capacity fuel valve operable when open to permit fuel flow to'the main burner at a relatively low rate, there being fluid pressure operated actuating means for said .main valve and a thermoelectrically powered operator having a pair of armatures, one for actuating the low capacity fuel valve, and the other for actuating pilot valve meansffor said fluid pressure operated actuating means, actuation of said low capacity fuel valve and of said pilot valvemeans requiring only a relatively small amount of power, thus permitting remote location of the thermostat controlling said control device.

Another object of the invention is to provide an improved fuel control device of the aforementioned character wherein the electromagnetic operator has a pair of energizing windings and is so constructed that energization of both of said windings is required to effect armature actuation, said energization effecting actuation of both of said armatures to attracted position and thereby opening of both the high and low capacity valves to thereby inherently afford a high rate of fuel flow tothemain burner for safe initiation of ignition of the" fuel thereat, subsequent deenergization of-one of said coils'etrecting' drop 2,909,218 Patented Oct. 20, 1959 out of one of the armatures and closure of the high capacity fuel valve to permit fuel flow to the main burner through said low capacity fuel valve at the relatively low rate which is at least sufficient to afford safe burning of the fuel at the main burner.

Another object of the invention isto provide an improved fuel control device of the class described, the operator of which includes an electromagnet frame having a separate pair of pole pieces cooperable with each of the armatures, energization of the first winding aifording flux flow through said first armature and the pole pieces cooperable therewith to provide attractive force sufficient to hold said first armature in attracted position when moved thereto against the bias, energization of the second winding while the first armature is in attracted position affording with the flux from the first winding a flux density more than suflicient to saturate a portion of said frame, wherefore flux is shunted from said saturated portion through the other pair of pole pieces to link the second armature and actuate the latter to attracted position against a bias.

Still another object of the invention is to provide an improved fuel control device of the aforementioned character wherein both of the energizing windings are connected for energization by athermoelectric generator, energization of each of said windings being under the control of a separate thermostat contact.

Still another object of the invention is to provide an improved fuel control device of the class described wherein there is pressure regulating means operatively connected to the high capacity fuel valve for movement therewith and operable to maintain the pressure of the fuel delivered to the main burner within predetermined limits had to the accompanying drawings illustrating one complete embodiment of the invention and wherein like characters of reference indicate the same parts in all of the views. In the drawings:

Figure l is a vertical sectional View taken through the improved control device with the fuel connections thereto shown diagrammatically; and

Figure 2 is a diagrammatic view showing the electrical system of the improved control device including a two stage thermostat, parts of which are broken away in section.

Referring more particularly to Figure 1 of the drawing, the illustrated form of the improved control device comprises a control body 4 which may be made up of superimposed body parts 5, 6 and 7, the body part 5 being formed with an inlet chamber 8 for receiving a fuel supply conduit 9 and also being formed with a fuel outlet chamber 10 from which fuel'may be delivered, for example through a conduit 11, to a main burner 12. The body part 5 is formed with a partition 13 separating the inlet chamber 8 from the outlet chamber 10 and formed with an annular valve seat 14 for, cooperation with a relatively high capacity fuel valve member 15. The partition 13 may also be formed with a tapered or conical surface 16 for a purpose to be more fully described hereinafter. The body part6 is formed with a recess 17a, and a diaphragm 18, which is marginally clamped by the body. par-ts 5 and 6 forms a chamber 17 with said recess. A seal between the body parts 5 and 6 is effected by means of a gasket 19. The diaphragm 18 is centrally clamped between the valve member 15 and a back-up plate 20, and the valve member 15 may be biased toward seated engagement with respect to the seat 14 by means of a compression spring 21. The spring 21 may be deleted if desired.

The body part 6 is formed with a passageway 22 therethrough which communicates at its lower end with a branch passage 23 formed in the body part and intersecting the inlet chamber 8 as shown. The body part 6 is formed with an annular valve seat 24, and a relatively small capacity fuel valve 25 cooperates with said seat to control the flow of fuel from the passageway 22 into a passage 26. A conduit 27 affords communication between the passage 26 and a passage 28 formed in the body part 5 in communication with the outlet chamber as shown. A metering screw 29 may be provided for adjusting the amount of fuel which can flow into the outlet chamber 10 through the passage 28. The small capacity valve member is carried by a spiral biasing spring 30 which biases said valve member toward the seat 24, said spring also carrying a magnetic member or magnetically permeable armature 31.

The body part 6 is also formed with a recess 32 formed with an annular valve seat 33 surrounding a bleed port or passage 34 which may communicate with a bleed conduit 35 extending to a position adjacent the main burner 12 as shown. A bleed port valve 36 cooperates with the seat 33 and is carried by a spiral spring 37 which biases said valve toward said seat. Also carried by the spiral spring 37 is a magnetic member or magnetically permeable armature 38. A passage 39 affords communication between the recess 32 and the chamber 17 as shown.

The body part 7 is provided with a cover member 40 having a centrally disposed depending lug 41. A magnetic member or magnetically permeable electromagnet frame 42 shown most clearly in Figure 2, is generally H-shaped in plan view and has a cross bar portion formed with an aperture 43 separating portions of reduced

cross section

105 and 106. As shown in Figure 1, the depending lug 41 projects through the aperture 43 in the frame 42, and said frame is held in abutting relation with the underside of the cover member 40 by means of a friction clip 44 which engages both the lug 41 and the

portions

105 and 106 of said frame.

As shown in Figure 2, each of the arms of the electromagnet frame 42 is provided with a depending leg or pole piece, said legs or pole pieces being indicated by the

numerals

45, 46, 47 and 48. The body part 7 is sealingly connected to the body part 6, as by a gasket 49, and the body part 7 is formed with a partition 50 defining a recess 51 which with the recess 32 forms a chamber 52. The partition 50 is formed with a pair of slots (not shown) through which the depending

legs

47 and 48 of theelectromagnet frame 42 project into the chamber 52. A sealing gasket 53, for example of rubber, is disposed within the recess 51 and is formed with slots (not shown) to snugly receive the depending

legs

47 and 48, and a clamping plate 54 of non-magnetic material is also disposed within the recess 51 and is formed with slots (not shown) to receive the depending

legs

47 and 48. The clamping plate 54 is staked in operative position clamping the sealing gasket 53 between said plate and the partition 50 to form a gas tight seal around the

legs

47 and 48.

The partition 50 is also formed with an opening 55 intermediate the

legs

47 and 48, and the gasket 53 is formed with a coaxial tapered opening 56 while the clamping plate 54 is also formed with a coaxial opening 57. Pilot valve means or a frusto-conical valve member 58 is movable into and out of seating engagement with the tapered opening 56 and is provided with a stem portion 59 extending loosely through the aperture 55 and having a connection with one end of a leaf spring 60, the other end of said spring being anchored to the partition 50 as by a screw 61. The leaf spring 60 biases the valve member 58 downwardly toward flow permitting position with re-, spect to the opening 56 and also tends to bias the lower end of the stem 59 into engagement with the armature 38 as shown. 7

The lower ends of the

electromagnet frame legs

45 and 46 terminate in coplanar pole faces, and the lower ends of the

legs

47 and 48 also terminate in coplanar pole faces. The armature 31 is movable from the retracted position shown in Figure 1 to an attracted position in engagement with the pole faces of the

frame legs

45 and 46. Similarly, the armature 38 is movable from the retracted position shown into engagement with the pole faces of the

frame legs

47 and 48. As the armature 38 moves toward attracted position, such movement effects seating of the valve member 58 within the opening 56, and simultaneously lifts the bleed port valve 36 off the annular seat 33.

An energizing winding 62 is wound on the frame leg 45, and an energizing winding 63 is wound on the frame leg 46. A thermoelectric generator 64, which may take the form of a thermocouple, is disposed with its hot junction or junctions subject to the heat of burning fuel at a pilot burner 65 which is mounted in coacting relation with the .main burner 12 as shown in Figure 1. One terminal of the generator 64 may be grounded as shown, and the other terminal of said generator is connected, as by a conductor 66 to one end of each the

windings

62 and 63. The other end of the winding 62 is connected to an insulated contact 67 of a two stage thermostat 68, by a conductor 69, and the other end of the winding 63 is connected to an insulated contact 70 of said thermostat by a conductor 71.

While the two stage thermostat 68 may take a variety of forms, the illustrated form is believed to be preferable. The thermostat 68 comprises a frame having

side walls

72 and 73 and an end wall 74, the latter having one end of each of a pair of expansible and contractible hermetically sealed

metallic bellows

75 and 76 fixed thereto. The contact 67 sealingly and fixedly extends through the end wall of the bellows 75 and adjacent the frame wall 74, and the opposite end wall of said bellows carries a contact 77 which is movable toward and away from circuit-making engagement with the contact 67 on expansion and contraction of the bellows 75. Similarly, the contact 70 sealingly and fixedly extends through the end Wall of the bellows 76 adjacent the frame end wall 74, and the opposite end wall of said bellows carries a contact 78 which is movable toward and away from circuit-making engagement with the contact 70 on expansion and contraction of the bellows 76. The thermoelectric circuits between the

coils

62 and 63 and the grounded terminal of the thermoelectric generator is completed by grounding of the thermostat frame, as through a conductor 97.

A capillary tube 79 has

branches

80 and 81 communicating with the interiors of the

bellows

75 and 76 respectively, and the free end of said tube terminates in a temperature sensing bulb 82 for sensing temperatures remote from said bellows. The contacts of the thermostat 68 are of low resistance, and the bulb 82, tube 79 and the

bellows

75 and 76 preferably contain a temperature responsive expansible and contractible volatile fluid fill of a character which will not deleteriously effect the low resistance character of the contacts within said bellows.

Means is provided for supplying a contractile bias to the

bellows

75 and 76 and for selectively adjusting the control points of the contacts therein simultaneously. The aforementioned means may take the form of a generally U-shaped yoke 83 which is slidable longitudinally of the bellows, for example between guides 84 projecting inwardly from the

frame side Walls

72 and 73. The yoke 83 carries a stem or plunger member 85 which is slidable in a bearing member 86 and engages a cam 87 carried by a shaft 88 which may be provided with a manually engageable knob (not shown). A compression spring 89 has one end abutting the inner end wall of the bellows 75 and has its opposite end received by a retainer plate 90 carried by a factory adjustment screw B 91 threaded through a suitable aperture in' the yoke 83 andprovided with lock nuts 92 for locking the screw 91 in a selected position. A compression spring 931has one end thereof abutting the inner end wall of the bellows 76 and has its opposite end receivedby a retainer plate 94 carried by a factory adjustment screw 95 which is threaded through a suitable aperture in the yoke 83 and is provided with lock nuts 96 for locking the screw 95 in a selected position of adjustment. It will be observed that the bias of

springs

89 and 93 exert forces tending tocompress the

bellows

75 and 76 and tending to move the yoke 83 toward the right as viewed in Figure 2 to thereby maintain the plunger 85in engagement with the cam 87. It will also be observed that by rotation of the cam 87, the amount of bias exerted on both of the

bellows

75 and 76 can be adjusted simultaneously thereby adjusting both of the control points of said thermostat simultaneously. The differential between the control points of the contacts 77 and 78 can be adjusted by adjustment of the

screws

91 and 95, it being preferred to have the control point of the contact 77 set somewhat higher, for example 3 F., than that of the contact 78.

Where regulation of the pressure of the fuel to the main burner 12 is desired, the improved control device may be provided With means therefor which will now be described. Fixed to and depending from the high capacity valve member 15 is a stem member 98 which carries a frusto-conical flow limiting member 99. The stem member 98 carries at its lower end a U-shaped bracket 100 having outturned ear portions. Cooperable with the bracket 100 is a generally U-shaped bracket 101 having inturned ear portions overlapping those of the bracket 100 as shown. A spring 102, extending within a suitable passage 103, formed in the body portion 5, has one end anchored to the bracket 101 and has its opposite end anchored to a set screw 104 threaded into the passage 103 as shown.

' The arrangement of the parts of the pressure regulating means is such that when the high capacity valve member 15 is raised to its normal open position, the member 99 and bracket 100 are lifted therewith to move the outturned ears of the bracket 100 into engagement with the inturned ears of the bracket 101. In this position the flow restricting member 99 exerts no substantial restriction upon the flow of fuel past the seat 14. If, however, the pressure of the fuel supplied to the conduit 9 is increased to a value above normal, the effect of this increased pressure on the underside of the diaphragm 18 tends to lift the valve member 15 farther, whereupon the flow restricting member 99 is raised against the bias of the spring 102 acting through the brackets 100 and 101. Such further movement of the member 99 restricts the amount of fuel which can flow past the valve seat 14 and thereby reduces the pressure of the fuel in the outlet so that said pressure is maintained within predetermined limits in spite of substantial fluctuations in the pressure of the fuel in the inlet chamber 8.

The operation of the improved control device will now be described. The parts of the improved control device are disposed as shown in Figure 1 when the thermostat 68 is not calling for heat, the temperature sensed by the bulb 82 at such a time being sufliciently high so that expansion ofthe fluid fill in the

bellows

75 and 76 has moved the contacts 77 and 78 to circuit-interrupting position for deenergization of the

windings

62 and 63. The small capacity valve 25 being seated on the seat 24, prevents fuel flow to the main burner past said seat. Disposition of the armature 38 in the position shown in Figure 1 effects closure of the bleed valve36 and permits the leaf spring 60 to open the valve member 58. This permits fuel to flow from the inlet chamber 8 through the

passages

23 and 22 and through the passage 55 in the partition 50, into the chamber 52, to pressurize said chamber and, through the passage 39, to pressurizethe chamber 17 above the diaphragm 18. Pressurizing of the chamber 17 with line pressure effects closure of the valve member 15. Since both the small capacity valve 25 and the large capacity valve 15 are closed, no fuel can flow to the main burner 12.

As the temperatures sensed by the bulb 82 drops to the control point of the contact 77, engagement of the contact with the contact 67 completes the circuit between the generator 64 and the winding 62 for energization .of the latter. This causes generation of flux which flows through a magnetic'path including the leg 45, the cross bar portions and .106, and the leg 46, and links the armature 31. The flux generated by energization of the winding 62 is, however, insuflicient to elfect pull-in of the armature 31 against the bias of the spring 30.

As the temperature sensed by the bulb 82 continues to drop and reaches the control point of the contact 78, the latter engages the contact 70 to complete the energizing circuit between the generator 64 and the winding 63 for energization of the latter. The energized winding 63 generates a flux which flows in the same direction as that generated by the winding 62, and the combined flux is sufficient to effect pull-in of the armature 31 and opening of the small capacity valve 25. As the armature 31 pulls in, the reluctance of the aforementioned magnetic path is reduced, and the combined flux is greater in magnitude than that which can be accommodated by the reduced

cross section portions

105 and 106. As a result, the

portions

105 and 106 become saturated, and the excess flux flows through the depending

legs

47 and 48 to link the armature 38 and effect pull-in thereof against the bias of the springs 37 and 60. Pull-in of the armatures 31 and 38 is substantially simultaneous, though sequential.

Pull-in of the armature 38 closes the valve 58 and unseats the bleed port valve 36 to bleed the chamber 17 to the atmosphere through the passages 39 and 34. The line pressure acting on the underside of the large capacity valve 15 is now sufficient to lift said valve against the bias of the spring 21 to permit fuel flow to the main burner 12 past both the high and the low capacity valves, thus supplying a relatively large volume of fuel to said main burner insuring safe ignition of said fuel by the pilot burner 65.

As the temperature sensed by the bulb 82 increases as a result of a high flame at the main burner and reaches the control point of the contact 78, said contact moves to circuit-interrupting position with respect to the contact 70 to deenergize the winding 63. Since the flux generated by the winding 62 is less than that which effects saturation of the

cross bar portions

105 and 106 of the frame 42, said portions become unsaturated and flux flow linking the armature 38 is terminated to cause drop out of the latter. The flux generated by the winding 62 is, however, sufllcient to hold the armature 31 in attracted position and thereby the valve 25 in open position.

As the armature 38 drops out, the valve 58 is opened, and the bleed port valve 36 is closed, so that the chamber 17 becomes pressurized as aforedescribed to cause closure of the high capacity fuel valve 15 Fuel flow to the main burner 12 is now restricted to that which is permitted by the adjustment of the metering screw 29, for example to 20% of the rate input of the main burner 12, and a low flame results.

Should the temperature sensed by the bulb 82 continue to rise with the low flame at the burner 12, the resultant expansion of the volatile fill causes the contact 77 to move to circuit-interrupting position with respect to the contact 67 as the control point temperature of the contact 77 is reached. Circuit-interrupting movement of the contact 77 effects deenergization of the winding 62, whereupon the armature 31 drops out under the bias of the spring 30 to close the low capacity valve 25 and shut-off all fuel flow to the main burner 12.

.If, on the other hand, the low flame at the main burner 12 is insuflicient to maintain the temperature level at 'the bulb 82, and the temperature thereat drops to the control point of the contact 78, said contact moves into and low flame positions in accordance with the demands of the thermostat 68 as long as the temperature sensed by the bulb 82 does not exceed the control point of the contact 77, and as long as the generator 64 continues to be heated by the flame of the pilot burner. On pilot burner outage, the

windings

62 and 63 are deenergized on cooling of the generator 64 to effect shut-oif of all fuel flow even though the thermostat 68 may be calling for heat at the time.

Various changes and modifications may be made in the improved control device without departing from the spirit of the invention. For example the

windings

62 and 63 and their respective controlling contacts may each be powered by a separate thermoelectric generator instead of being connected in parallel circuit with and powered by the simple thermoelectric generator 64. Also, the pressure regulating means disclosed may be omitted where pressure regulation is not desired. Other modifications of the details of construction shown and described will occur to those persons skilled in the art; all of such modifications being contemplated as come .within the spirit of the appended claims.

What is claimed as the invention is:

1. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, means for controlling the flow of fuel to .said reduced capacity fuel outlet comprising a first control member having flow-permitting and flow-preventing positions, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first flow control member to position the latter in flow-permitting position when said magnetic members are in attracted relative positions and in flow-preventing position when said members are in separated relative positions, means to establish magnetic flux flow through said fiuX path at a first density level sufiicient to hold said magnetic members in said attracted relative positions against said biasing means and through the same path at a predetermined higher density level, said low reluctance flux path means including a portion'having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, and means for controlling the flow of fuel through said high capacity f-uel outlet comprising a magnetic second control member including means biasing said second control member toward a flowpreventing position in which it is linked by said shunted flux and movable against said biasing means toward a flow-permitting position in which it is held by said shunted flux when moved thereto.

2. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adpted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel to said reduced capacity fuel outlet having open and closed positions, a second valve for controlling the flow of fuel to saidhigh capacity fuel outlet, fluid pressure operated means for actuatingsaid second valve, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first valve to position the latter in open position when said magnetic members are in attracted relative positions and in closed position when said members are in separated relative positions, means to establish magnetic flux flow through said flux path at a first density level suflicient to hold said magnetic members in said attracted relative positions against said biasing means and through the same path at a predetermined higher density level, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, and pilot valve means for controlling said actuating means comprising a magnetic control'member and means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and in which it effects disposition of said second valve in closed position and movable against its said biasing means toward a second position in which it is held by said shunted flux when moved thereto and in which it effects disposition of said second valve in open position.

3. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel to said reduced capacity fuel outlet having open and closed positions, a second valve for controlling the flow of fuel to saidhigh capacity fuel outlet, fluid pressure operated means for actuating said second valve, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated With said first valve to position the latter in open position when said magnetic members are in attracted relative positions and in closed position when said members are in separated relative positions, means to establish magnetic flux flow through said flux path at a first density level sufficient to hold said magnetic members in said attracted relative positions against said biasing means and through the same path at a predeterminted higher density level, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, Wherefore flux flow through said flux path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, and pilot valve means for controlling said actuating means comprising a magnetic control member and means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and in which it effects disposition of said second valve in closed position and movable against its said biasing means toward a second position in 'which it is held by said shunted flux when moved thereto and in which it effects disposition of said second valve in open position, and pressure regulating means in said control body operatively connected tosaid second valve for actuation thereby and operable to maintain the pressure of the fuel in said high capacity meat 9 fuel outlet within predetermined limits in spite'of substantial fluctuations in the pressure of the fuel in said inlet.

4. An electromagnetic control device, comprising means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, means to establish magnetic flux flo w through said flux path at a first density level sufiicient to hold said magnetic members in attracted relative positions against said biasing means and through the same path at a predetermined higher density level, said flux flow at said first density level affording insuificient attractive force to position said magnetic members in their said attracted relative positions against said biasing means, whereas flux flow at said higher density level suflicient to' effect such positioning, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux fiow therethrough at said first density level and saturable by flux fio w therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level positions said magnetic members in said attracted relative positions, and flux is shunted from said flux path adjacent said saturable portion, and a magnetic control member including means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and movable against said biasing means toward a second position in which it is held by said shunted flux when moved thereto.

5. An electromagnetic control device, comprising means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance fiuX path, means to establish magnetic flux flow through said flux path at a first density level sufficient to hold said magnetic members in attracted relative positions against said biasingmeans and through the same path at a predetermined higher density level, said flux flow at said first density level affording insufficient attractive force to. position said magnetic members in their said attracted relative positions against said biasing means, whereas flux flow at said higher density level is sufficient to effect such positioning, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level positions said magnetic members in said attracted relative positions, and flux is shunted from said flux path adjacent said saturable portion, and a magnetic control member including means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and movable against said biasing means to- Ward a second position in which it is held by said shunted flux when moved thereto, and thermostat means comprising first and second contacts in circuit with said flux flow establishing means for controlling the operation of the latter, positioning of said first contact in circuit-making position effecting flux flow at said first density level, and positioning of said second contact in circuit-making position While said first contact is in circuit-making position efiecting flux flow at said predetermined higher density level, the control point of said second contact being set at a predetermined lower temperature than that of said first contact.

6. An electromagnetic fuel flow controlling device comprising first and second valves, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, said first valve being operatively 10 associated with said magnetic members't'obe positioned in closed positionwhen said magnetic members are in separated relative positions and in open position when said magnetic members are in attracted relative positions against said biasing means and through the same path at a predetermined higher density level, said flux flow at said first density level affording insufficient attractive force to position said magnetic members in said attracted relative positions, whereas flux flow at said higher density,

level is sufiicient to so position said magnetic members and to open said first valve, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level causes said magnetic members tobe positioned in their attractive relative positions and flux is shunted from said flux path adjacent said saturable portion, and a magnetic control member operatively associated with said second valve and including means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and in which it effects closure of said second valve, said magnetic control member being movable toward a second position in which it effects opening of said second valve and in which it is held by said shunted flux when moved thereto.

7. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, means for controlling the flow of fuel to said reduced capacity fuel outlet comprising a first control member having flow-permitting and flow-preventing positions, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members also having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first flow controlling member to position the latter in flow-permitting position when said magnetic members are in attracted relative positions and in flow-preventing position when said magnetic members are in separated relative positions, means to establish magnetic flux flow through said flux path at a first density level suificient to hold said magnetic members in their attracted relative positions against said biasing means and through the same path at a predetermined higher density level, said flux flow at said first density level affording insufficient attractive force to position said mag netic members in their said attracted relative positions, Whereas flux flow at said higher density level is sufiicient to position said magnetic members in said attracted relative positions, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level positions said magnetic members in attracted relative posi tions and thereby said first control member in flow-permitting position and flux is shunted from said flux path adjacent said saturable portion, and means for controlling the flow of fuel through said high capacity fuel outlet comprising a magnetic second control member and means biasing said magnetic second control member toward a flow-preventing position in which it is linked by said shunted flux and movable against its biasing means toward a flow-permitting position in which it is held by said shunted flux when moved thereto, thus affording fuel flow to said burner through both outlets for safe ignition, subsequent reduction in the flux flow to said first density level effecting release of said second control member for movement to its flow-preventing position under its biasing means for shut off of the fuel flow through said high capacity outlet while reduced fuel flow to said burner through said reduced capacity outlet is permitted by said first control member.

8. An electromagnetic control device for controlling the fiow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, means for controlling the flow of fuel to said reduced capacity fuel outlet comprising a first control member having flow-permitting and flow-preventing positions, means including magnetic members and means biasing said magnetic members to separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first control member to position the latter in its flow-permitting position when said magnetic members are in their attracted relative positions and to position said first control member in its flow-preventing position when said magnetic members are in their seperated relative positions, means to establish magnetic flux flow through said flux path at a first density level sufi'icient to hold said magnetic members in their attracted relative positions against said biasing means and through the same path at a predetermined higher density level, said flux fiow at said first density level affording insufficient attractive force to position said magnetic members in their attracted relative positions from their separated relative positions, whereas flux flow at said higher density level is sufficient to position said magnetic members in their attracted relative positions from their separated relative positions, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level'and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore on flux flow through said flux path at said higher density level said magnetic members are positioned in their said attracted relative positions and thereby said first control member is positioned in its flow-permitting position and flux is shunted from said flux path adjacent said saturable portion, means for controlling the flow of fuel through said high capacity fuel outlet comprising a magnetic second control member and means biasing the same toward a flow-preventing position in which it is linked by said shunted fiux, said magnetic second control member being movable against its said biasing means toward a flow-permitting position in which it is held by said shunted flux when moved thereto, thus affording fuel flow to said burner through both outlets for safe ignition, subsequent reduction in the flux flow to said first level effecting release of said second control member for movement to its flow-preventing position by its biasing means for shutoff of the fuel flow to said high capacity outlet while reduced fuel flow to said burner through said reduced capacity outlet is permitted by said first control member, and thermostat means comprising first and second contacts in circuit with said flux flow establishing means for controlling the operation of the latter, circuit-making movement of said first contact effecting flux flow at said first density level, and circuitmaking movement of said second contact while said first contact is in circuit-making position effecting flux flow at said predetermined higher density level, the control point of said second contact being set at a predetermined lower temperature level than that of said first contact.

9. An electromagnetic control device for controlling the fiow of fuel to fluid burning apparatus having a bumer, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel to said reduced capacity fuel outlet, a second valve for controlling the fiow of fuel to said high capacity outlet, fluid pressure operated means for actuating said second valve, means including magnetic members and means biasing said members toward separated relative positions, said magnetic members also having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first valve to position the latter in its closed position whenever said magnetic members are in their attracted relative positions and to position said first valve in open position whenever said magnetic members are in their separated relative positions, means to establish magnetic flux flow through said flux path at a first density level sufficient to hold said magnetic members in their said attracted relative positions against said biasing means and through the same path at a predetermined higher density level, said flux flow at said first density level affording insufficient attractive force to position said magnetic members in their said attracted relative positions from their said separated relative positions, whereas flux flow at said higher density level is sufiicient to position said magnetic members in their attracted relative positions and to open said first valve, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux fiow therethrough at said first density level and saturable by flux fiow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level positions said magnetic members in their said attracted relative positions and thereby said first valve in its said open position and flux is shunted from said flux path adjacent said saturable portion, and pilot valve means for controlling said actuating means comprising a magnetic control member and means biasing the same toward at first position in which it is linked by said shunted flux and in which it effects disposition of said second valve in closed position, said magnetic control member being movable against its biasing means toward a second position in which it is held by said shunted flux and in which it effects dispostion of said second valve in open position, thus affording fuel How to said burner through both said outlets for safe ignition, subsequent reduction in the flux flow to said first density level effecting release of said control member for movement to its first position under its bias and closure of said second valve for shut off of the fuel fiow through said high capacity outlet while reduced fuel flow to said burner through said reduced capacity outlet is permitted by said first valve.

10. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel to said reduced capacity fuel outlet, a second valve for controlling the flow of fuel to said high capacity outlet, fluid pressure operated means for actuating said second valve, means including magnetic members and means biasing said members toward separated relative positions, said magnetic members also having attracted relative positions providing a low reluctance fiux path, said magnetic members being operatively associated with said first valve to position the latter in its closed position whenever said magnetic members are in their attracted relative positions and to position said first valve in open position whenever said magnetic members are in their separated relative positions, means to establish magnetic flux flow through said flux path at a first density level sufficient to hold said magnetic members in their said attracted relative positions against said biasing means and through the same path at 13 a predeterminedhigher density level, said flux flow at saidfirst density level alfording' insulficient attractive force" to position said magnetic members in their said attracted relative positions from their said separated relativepositions, Whereas flux flow at said higher density level is sufiicient to position said magnetic members in their attractedrelative positions and to open said first valve, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore fiuX flow through saidflux pathat saidhigher density level positions said magnetic members in their said attracted relative positions and thereby said first valve in its said open position and [flux is shunted from said flux path adjacent said saturable portion, and pilot valve means for controlling said actuating means comprisinga magnetic control member and means biasing the same toward a first position in which it is linked by said shunted flux and in which it effects disposition of said second valve in closed position, said magnetic control member being movable against its biasing means toward a second position in which it is held by said shunted fluxand' in whichit effects disposition of said second valve in open position, thus affording fuel new to said burner through both said outlets for safe ignition, subsequent reduction in the flux flow to said first density level effecting release of said control member for movement to its first position under its bias and closure of said second valve for shut ofi of the fuel flow through said high capacity outlet while reduced fuel flow to said burner through said reduced capacity outlet is permitted by said first valve, and pressure regulating means in said control body operatively connected to said second valve and cooperable with said fluid pressure operated actuating means to maintain the pressure of the fuel at said high capacity outlet Within predetermined limits in spite of substantial fluctuations in the pressure of the fuel at said inlet. V

11. Anelectromagnetic control device, comprising means including magnetic members and means biasing said magnetic members toward retracted relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, first flux generating means for establishing magnetic flux flow through said flux path at a first density level suflicient to hold said moveable members in their said attracted relative positions against said biasing means but insufficient to cause said magnetic members to be positioned in their attracted relative positions from their said retracted relative positions, second flux generating means operable with said first flux generating means to establish flux flow through the same path at a predetermined higher density level suificient to position said magnetic members in their said attractive relative positions from their said retracted relative positions against said biasing means, said flux path meanshaving a portion having a cross-sectional area of a size permitting fiux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, Wherefore flux flow through said flux path at said higher density level causes, flux to be shunted from said flux path adjacent said saturable portion, and a magnetic control member including means biasing said magnetic control mem ber toward a first position in which it is linked by said shunted flux and movable against said biasing means to- [Ward a second position in which it is held by said shunted flux when moved thereto.

12. An electromagnetic control device comprising means including magnetic members and means biasing said magnetic members toward retracted relative positions, said magnetic members having attracted relative positions providing a low reluctance fluxpath, first flux generating means for establishing magnetic flux flow through said flux path at a first density levelsuflicient to,

hold said moveable members in their saidiattracted rela-' tive positions against said biasing means but insufficient to position said magnetic members in their said attracted relative positions from their said retracted relative positions, second flux generating means operable with said first flux generating means to establish flux flow through the same path at a predetermined higher density level sufficient to position said magnetic members in their said attracted relative positions from their said retracted relative positions against said biasing means, thermoelectric genera-tor means connected to energize said first and second flux generating means independently, said fiux path means having a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, and a magnetic control member including means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and moveable against its said biasing means toward a second position in which it is held by said shunted flux when moved thereto.

13. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel to said reduced capacity fuel outlet having open and closed positions, a second valve for controlling the flow of fuel to said high capacity fuel outlet, means including magnetic members and means biasing said magnetic members toward separated relative poistions, said magnetic members having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first valve to position the latter in open position when said magnetic members are in their said attracted relative positionsand to closed position when said magnetic members are in their said separated relative positions, first flux generating means to establish magnetic flux flow through said flux path at a first density level sufiicient to hold said magnetic members in their said attracted relative positions against said biasing means but insufficient to effect positioning of said magnetic members in their said attracted relative positions from their said separated relative positions, second flux generating means operable with said first flux generating means to establish flux flow through the same path at a predetermined higher density level suflicient to effect positioning of said magnetic members in their said attracted relative positions from their said separated relative positions and hence opening of said first valve, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting fiux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, and means for actuating said second valve comprising a magnetic control member and means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and in which it elfects disposition of said second valve in closed position and movable against its said biasing means toward a second position in which it is held by said shunted flux when moved thereto and in which it effects disposition of said second valve in open position.

, 14. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a.

burner, comprising a flow control body having an inlet, and a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel to said reduced capacity fuel outlet having open and closed positions, a second valve for controlling the flow of fuel to said high capacity fuel outlet, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first valve to position the latter in open position when said magnetic members are in their attracted relative positions and to closed position when said magnetic members are in separated relative positions, first flux generating means energizable to establish magnetic flux flow through said flux path at a first density level sufficient to hold said magnetic members in their said attracted relative positions against their said biasing means but insufficient to position said magnetic members in their said attracted relative positions from their said separated relative positions against their said biasing means, second flux generating means operable when energized with said first flux generating means to establish flux flow through the same path at a predetermined higher density level sulficient to position said magnetic members in their said attracted relative positions and hence open said first valve, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, means for actuating said second valve comprising a magnetic control member and means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and in which it effects disposition of said second valve in closed position and movable against its said bias toward a second position in which it is held by shunted flux when moved thereto and in which it effects disposition of said second valve in open position, and thermostat means comprising first and second contacts in circuit with said first and second flux generating means respectively for controlling the energization thereof, circuit-making movement of said first contact effecting energization of said first flux generating means, and circuit-making movement of said second contact effecting energization of said second flux generating means, the control point of said second contact being set at a predetermined lower temperature than that of said first contact.

15. An electro-magnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel to said reduced capacity fuel outlet having open and closed positions, a second valve for controlling the flow of fuel to said high capacity fuel outlet, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attracted relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first valve to position the latter in open position when said magnetic members are in attracted relative positions, and to closed positions when said magnetic members are in separated relative positions, first flux generating means to establish magnetic flux flow through said flux path at a first density level suificient to position said magnetic members in their said attracted relative positions against said biasing means but insufficient to effect movement thereof from their said separated relative positions to their said attracted relative positions, second flux generating'means operable with said first flux generating means to establish flux flow through the same path at a predetermined higher density level sufiicient to position said magnetic members in their said attracted relative positions from their said separated relative positions and hence said first valve, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, and fluid pressure operated means for actuating said second valve, and pilot valve means for controlling said actuating means including a magnetic control member and means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and in which it effects disposition of said second valve in closed position and movable against its biasing means toward a second position in which it is held by said shunted flux when moved thereto and in which it effects disposition of said second valve in open position.

16. An electromagnetic control device for controlling the flow of fuel to fluid burning apparatus having a burner, comprising a control body having an inlet, having a high capacity fuel outlet adapted to be in communication with said burner, and having a reduced capacity fuel outlet also adapted to be in communication with said burner, a first valve for controlling the flow of fuel tosaid reduced capacity fuel outlet having open and closed positions, a second valve for controlling the flow of fuel to said high capacity fuel outlet, means including magnetic members and means biasing said magnetic members toward separated relative positions, said magnetic members having attractive relative positions providing a low reluctance flux path, said magnetic members being operatively associated with said first valve to position the latter in open position when said magnetic members are in attracted relative positions and in closed position when said magnetic members are in separated relative positions, first flux generating means to establish magnetic flux flow through said flux path at a first density level sufficient to hold said magnetic members in their said attracted relative positions against said biasing means but insufiicient to position said magnetic members in their said attracted relative positions from their said separated relative positions against said biasing means, second fiux generating means operable with said first flux generating means to establish flux flow through the same path at a predetermined higher density level sufficient to change the relative positions of said magnetic members from their said separated relative positions to their said attracted relative positions and hence open said first valve, said low reluctance flux path means including a portion having a cross-sectional area of a size permitting flux -flow therethrough at said first density level and saturable by flux flow therethrough at less than said predetermined higher density level, wherefore flux flow through said flux path at said higher density level causes flux to be shunted from said flux path adjacent said saturable portion, fluid pressure operated means for actuating said second valve, and pilot valvemeans controlling said actuating means including a magnetic control member and means biasing said magnetic control member toward a first position in which it is linked by said shunted flux and in which it effects disposition of said second valve in closed position and movable against its said biasing means toward a second position in which it is held by said shunted flux when moved thereto and in which it effects disposition of said second valve in open position, and pressure regulating means in said control body operatively connected to said second valve and cooperable with said fluid pressure actuating means to maintain the pressure at said high capacity outlet within predetermined limits in spite of substantial fluctuation in the pressure of the fuel in said inlet.

17. A flow control device for controlling the flow of fluid to fluid fuel burning apparatus comprising high and low capacity valves, an electromagnetic operator for said valves including permeable core means, first and second flux generating means, and magnetic members and means respectively biasing said magnetic members toward retracted relative positions with respect to said core means, said magnetic members being operatively associated individually with said low and high capacity fuel valves, each of said magnetic members having an attracted position with respect to said core means in which it elfects opening of its respective valve, energization of said first flux generating means causing the latter to generate suflicient flux in said core means to hold one of said magnetic members in attracted position and said low capacity valve in open position when moved thereto against the respective biasing means but insuflicient to efiect attractive movement of either of said magnetic members against its said biasing means, energization of said second flux generating means while said first flux generating means is energized effecting additional flux flow in said core means and actuation of both of said magnetic members to their attracted positions with respect to said core means and thereby both of said valves toward their open positions, energization of said second winding alone generating insuificient flux to hold or actuate either of said magnetic members to their attracted positions, wherefore initiation of fuel flow to said apparatus is always at a high rate for safe ignition since both valves are opened substantially simultaneously in response to energization of both windings, and thereafter said high capacity valve may be cycled by deenergization and reenergization of the second flux generating means while said low capacity valve is held open by energization of said first flux generating means, deenergization of said first flux generating means at any time elfecting retraction of said first magnetic member for closure of said low capacity fuel valve and shut 01f of all fuel flow to said apparatus.

References Cited in the file of this patent UNITED STATES PATENTS