US2408954A

US2408954A - Fuel supply system

Info

Publication number: US2408954A
Application number: US539377A
Authority: US
Inventors: William A Ray
Original assignee: General Controls Co
Current assignee: General Controls Co
Priority date: 1944-06-08
Filing date: 1944-06-08
Publication date: 1946-10-08
Anticipated expiration: 1963-10-08

Description

Oct. 8, 19460 w. A. RAY 2,408,954

I FUEL SUPPLY SYSTEM Filed June 8', 1944 2 sheetsfisnee't 1 lufomafl'c SWIM 7 2 Exusm Mice P/wfo fube%$ ENVENTQQ myl/a Fay BYMM ATTORNEY w. s, 1946. w. A. AY 12,408,954

FUEL SUPPLY SYSTEM Filed Jun 8-, 1944 2 Sheets-Sheet 2 HNVENTOR ,Wllx'am Aiay Bv%f i A'rrogusvg Patented Oct. 8, 1946 UNl-TE'D STATES PATE N-TOFFICE William A. Ray, Glendale, Calif., assignor to. General Controls Co a corporation Application June 8, 1944, smelled-539,377

This invention relates to a system for supplying fuel to a burner, and more particularly to a safety system ensuring against escape of unignited fuel.

This application my application filed on January 1, 1944, under Serial No. 516,733. r I

Inthat prior application, a fluid fuel control system is described that ensures automatic interruption in the supply of fuel in response to the occurrence of a condition that would render the system unsafe. The main elements of the system are either directly or indirectly energized by a commercial source of electrical energy. As an example, the system may be caused to respond to the extinguishment of a pilotfiame, to deenergize an electromagnetically operated valve.

Although systems of this general character are now well-known, they suffer from the disadvantags that when ther has been a power failure from the commercial source, the mere resumption of the supply of power is insufiicientto place the system into operative condition. It isnecessary in such systems, to reset 'a valve manually, and where the power failure extends over a considerable portion of a community, the process of resetting all of the valves involves a considerable expense and time. In said prior application, this difficulty is overcome, it being unnecessary to reset any of the valves, and the system im-' mediately resumes operation upon re-establishment of the power, Y

It is one of the objects of this invention to improve the system described in said prior application.

In the system described in said prior application, the controlling valve requiring resetting, and operated electromagnetically, is maintained open even upon power failure; and yet is closed in response to an unsafe condition. This is ac complished'first, by providing a direct current electromagnet that has suflicient reman nce to keep its'armature or core in attracted position even when ole-energized; and, second, by utilizing the power to provide an alternating de-magnetizing flux for the electromagnet. Normally, therefore, the remanence is neutralized and the electromagnetically operated valve responds to any control condition requiring it to close. But on power failure, the de-magnetizing force is ab sent, and the remanence is then effective to keep the reset valve open. This'open condition is not dangeroussince thepower failure causes anis a continuation in part of 9 Claims. (o1.15s '111.1)

other electromagnetically operated valve to close,

thus interrupting the fiow of fuel.

'Il'1is system requires a source of unidirectional current for the operation of the reset valve. Since almost allsources of commercial power are alternating current, a rectifier must bev provided. In addition, a safety control device is provided to respond to an unsafe condition, such as an extinguished burner flame.

It is another object. of this invention to combine the function 'of the rectifierand the safety control device; -and more particularly by using an electronic emission device that responds to theexistence of a pilot flame and'thatalso acts as a-rectifier for theisupply of unidirectional current to the reset valve. H It is still another object of this invention to effect a further simplification by operation of the main valve by unidirectional current derived fromthe electronic emission device. This is rendered possible by the use of an electronic emission tube that canpass power suificient to operate an appropriately designed electromagnetically operated valve. l

I For example, a type Of tube that can be effec: tively used for thispurpose isa multiplier phototube. This tube is arranged to be energized by a commercial source of alternating current, and the output of the tube is unidirectional. The current flow depends upon the intensity of illumination ofvthe photosensitive cathode. Thisintensity in turn is dependent upon the illumination created by the pilot flame, 7

It is still another object of this invention effectivelyto utilize such a phototube, both as a control device and as a source of unidirectional current for supplying power to the system.

I?his invention possesses many other advantages, and hasother objects which may be made more clearly apparentfrom a consideration of several embodiments of the invention. For. this purpose there are shown a few forms in the drawings accompanying and forming part of. the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to beunderstood that this detailed description is not to be taken in a limiting sense, since the scope. of they inventionis best defined by the appended claims.

Referring to the drawings: I

Figure 1 is a diagrammatic view of a system incorporating the invention; v v a Fig. 2 is awiring diagram of the system; and.

Fig. 3 is a wiring diagram of a slightly modified, form of the system.

Thesystem may be utilized for the control of fuel generally, such as liquid or gaseous fuels.

In the present instance a main burner I, adapted for gas fuel, is illustrated in Fig. 1. It is supplied from an appropriate source of fuel supply, as through the pipe 2. The flow of fuel to the burner is controlled by a main fuel valve 3, shown also in Figs. 2 and 3. A pilot burner 4 provides a flame 5 for igniting the burner I when valve 3 is opened. This pilot burner 4 is shown as supplied through conduit 6 leading to the pipe 2 and arranged back of the valve 3, so that closure of valve 3 will not serve to shut off the supply of fuel to the pilot burner 4. The conduit 6 is shown as including a pilot burner valve I, shown also-in Figs. 2 and 3. I

Both of the valves 3 and I are shown as'electrically operated. Furthermore, the control is such that, in the event of an unsafe condition,

such as extinguishing of pilot flame 5, both valves are caused to close. After the pilot valve 1 is closed, the arrangement is such that it will not re-open by mere re-establishment of the safe condition, but mustbe held open until the burner 4 is lighted and the flame 5 is re-established.

The safety control circuit includes a light-sensitive device, such as a phototube 8. that responds to the light produced by the pilot flame 5, to the substantial exclusion of any other light source, as by the aid of appropriate shields. A focussing device .9 may be used to project the light from flame 5 onto the light-sensitive electrode of tube 8.

The main valve 3 is diagrammatically illustrated in section in Fig. 2. It is shown as including a stem I 0 carrying a magnetic member or armature II. An electromagnet structure I2 serves to exert a pull upwardly upon the armature I I to open the valve 3 when the electromagnet I2 is sufliciently energized. Preferably this valve structure is such that a relatively small current of the order of one watt is sufficient to lift the armature I I for opening the valve,

Substantially the same type of structure is utilized for the pilot burner valve I. In this case the electromagnet associated with the valve includes a pair of coils I4 and I5 wound upon a magnetic core I6. The. arrangement is such that, once the armature I3 is released from the core I6, re-energization of the electromagnet does not cause lifting of the armature I3; instead, it must be urged upwardly toward the poles of the core It by the manual reset button II.. Accordingly, once the. flow of fuel to the pilot burner 4 is interrupted by valve 1, such flow cannot be reestablished until the button I! lifts the armature I 3 into the operative influence of magnetic member I5. Then while the valve I is held open, the pilot burner 4 can be ignited to re-establish the flame 5; and this in turn, causes operative energization of coil I4.

So long asthis flame 5 is in existence, the phototube 8- serves to control the circuits associated with the valves 3 and I, so as to maintain them in operative condition. As soon as the flame 5 is extinguished the phototube becomes inactive and these valves are caused to close.

One type of control circuit for effecting this result is illustrated in Fig. 2. In this arrangement, the phototube 8 is utilized to serve also as an electronic emission rectifier for supplying unidirectional current to the electromagnet I2 and to the coil I4 of valve I. Accordingly, the phototube 8 serves a plurality of functions: not only is it a control device, but it also serves to transmit rectified current to the system, capable f directly operating main valve 3.

In order that the phototube 8 transmit a sumcient current for the operation of valve 3, it is shown as of the multiplier type. One such tube is known as the 931-A. It includes a photosensitive cathode I8 which emits electrons when its active surface is illuminated, as by the flame 5. The anode I9 finally receives the electrons produced in the tube by successive action of the electrons upon a number of auxiliary electrodes or secondary emitters 20, 2I. 22, 23, 24, 25, 26, 21, and 28. In the present instance, nine such auxiliary electrodes are shown. In order that these electrodes serve effectively to reinforce the original electronic stream emanating from the cathode I8 by secondary emission, they are shown as connected by taps to the high voltage secondary coil 29 of a step-up transformer 30. The primary coil 3| may be connected to a commercial source of alternating current.

The operation of such a multiplier tube is well known. A relatively weak stream of electrons is dislodged from the photo-sensitive surface of cathode I8. This stream is greatly reinforced by secondary emission successively from the auxiliary electrodes 2!) to 28 inclusive the active surfaces of which are successively encountered by the electron stream. The output current between the anode I9 and cathode I8 is unidirectional.

Thus, for the operation of the electromagnet I2, the anode I9 is connected as by conductor 32 with the electromagnet I2. The other terminal of electromagnet I2 is shown as connected by connection 33 to an automatic switch 34 which may be a. thermostat or other condition responsive device. Thence, the current flows through connection 35 to the upper terminal of secondary coil 29. From the lower terminal of secondary coil 29, connection 36 leads to the cathode I8. The alternating current electromotive force across the terminals of secondary coil 29 is rectified through the unidirectional flow of electrons between the cathode I8 and the anode I9. The electromagnet I2 is connected to receive this rectified current, by the aid of the circuit iust traced.

This circuit is de-energized as soon as cathode I8 ceases to be illuminated by the pilot flame 5, and then valve 3 closes. However, upon reestablishment of flame 15, the electronic emission current passing through tube 8 is sumci'ent to re-energize the electrpmagnet I2, provided the automatic switch device 34 is closed.

As heretofore stated, the pilot burner valve I is arranged to close when there is a failure of the flame 5. However, it is arranged to be left open if there is a total failure of the power supply. In order to effect this result, use is made of a supplemental coil I5 'on core I6. Coil I4, normally energizing the electromagnet, is supplied with unidirectional current throu h the phototube 8. However, it is so connected that the current flow is considerably less than the current flow through the main valve electromagnet I2. For this purpose, the coil I4 is connected in the lead between any one of the auxiliary electrodes 20 to 28, and a tap on the secondary coil 29. In the present instance the coil I4 is interposed in the lead from auxiliary electrode 28 and its corresponding tap 31.- By appropriate choice of the auxiliary electrode, the quantity of current flow in coil I4 can be that most suitable; and therefore the magnctomotive force produced by the coil I4 is suflicient to m'aintain the armature I3 in attracted position, but

[4' is de-energized. Accordingly, in order that the armature l3 be released, the coil. 15 must be energized, for neutralizing the remanence. I

In the event of powerv failure, the coil 15 is not energized and, therefore, the remanenceof core I6 retains the armature 13 in attracted position, if the armature happens to be inthat position. The necessityof resetting each and every one of the valves-such as 1, that'are installed in a district where the power failure occurred is avoided. 'Nevertheless,'it is ensured that valve 3 closes when the power goes off, for electromagnet I2 is then de-energized. Normally, without any power failure, the pilot burner valve 1 is maintained open only 'while flame is in existence. As soon as flame 5 is extinguished, the phototube 8 becomes inactive. The electromagnet i2 is also de-energized, ensuring closing of the valve 3; and, at the same time, core I6 releases armature [3, thereby causing the closing of valve'l. The coil acts to neutralize the remanence of core I6, ensuring release of armature I3. Thetunsafe condition created by the extinguishing of flame 5 thus sets into operation the safeguardsthat ensure against any flow of unignited fuel.

Valve 3 is independentlycontrollable by the automatic switch or thermostat 34, which may respond to the temperature of the space to be heated. The valve 3 may be operated thereby to open and close, as required by temperature conditions.

In the form illustrated in Fig. 2, the coil 14 is provided with unidirectional current of appropriate potential difi'erence below the potential difference applied to the electromagnet I 2. This is accomplished, as heretofore stated, by interposing the coil M in the lead between one of the auxiliary electrodes and the secondary coil 29.

In the form illustrated in Fig. 3, the system operates substantially identically with that illustrated in Fig. 2, except that the reduced potential diiference of coil I4 is obtained in a slightly difierent way. In this form of the invention the electromagnet I2 is supplied, as before, with unidirectional current as by

appropriate connections

32, 33 and 35, as in-the form illustrated in Fig. 2. The coil 14 is placed in parallel with the electromagnet I2; and a resistance 38 included in the circuit of coil M to reduce the potential difference across the coil.

The inventor claims:

1. In a system of the character described, a burner, an electrically operated valve for controlling the flow of fuel to the burner, a photoelectric tube having a photosensitive cathode and adapted to be energized from a source of a1- ternating current, said device serving to rectify the alternating current, and supplying the resultant unidirectional current to operate said valve, and a light source afiecting the cathode for controlling the flow of said unidirectional current.

2. In a system of the character described, a

burner, an electrically operated valve forYcon-' trolling the flow of fuel to'the burner, a photoelectric tube having a photosensitive cathode and adaptedto be energized from a source of alternatingcurrent, said device serving to rectify the alternating current, and supplying the. resultant unidirectional current to operate said valve and alight source affecting the cathode for controlling the fiow of said unidirectional current, said light source being active in response to a condition of operation of said system.

3. In a system of the character described, a main burnerza pilotiburner for providing a pilot flame, an electrically operated valve forcontrolling the flow 'offuel tothe main burner, and a photo-electric tube having a photosensitive cathode and adapted to be energized by a source-of alternating current, said device serving to rectify theialternating current, and supplying the resultant unidirectional current to operate said valve, the flame of the pilot burner supplying illumination for the cathode, to causean'operating unidirectional current toflowfor electri' cally operating the valve. .4. In a' system of thecharacter described, a main burner, a pllotburner for producing a pilot flame, an electrically operated valve for controlling theflow of fuel to. the main'b-urner, an electrically operated valve forthe, pilot burner, having a magnetic member and a coil for-magnetizing said member, an electronic emission. device, adapted to be energized from a source of alternating current,'said device serving to-rectify the alternating current, and-supplying the resultant unidirectional current-to; operate both of said valves, said electronic emission device including meanscausingflow of saidunidirectional current of sufficient quantity to operate said main valve, only while the pilot flame is in existence, said device also supplying'unidirectional currentto the pilot burner valve coilfor holding the pilot burner valve, open, the remanence of the magnetic member being sufficient to retain the pilot burner valve open after the coil is de-energized, and a demagnetizing coil for the magnetic member and supplied from the source of alternating current, said demagnetizing coil operating to render said remanence ineffective while the source of alternating current is active.

5. In a system of the character described, a main burner, a pilot burner for producing a pilot flame, an electrically operated valve for controlling the flow of fuel to the main burner, an electrically operated valve for the pilot burner, having a magnetic member and a coil for magnetizing said member, a photo-electric tube having a photosensitive cathode and aifected by the pilot flame, said tube being adapted to be energized from a source of alternating current, for supplying unidirectional current to operate the main valve only while the pilot flame is in existence, said device also supplying unidirectional current to the pilot burner valve coil for holding the pilot burner valve open, the remanence of the magnetic member being sufficient to retain the pilot burner valve open after the coil is de-energized, and a demagnetizing coil for the magnetic mem-- ber and supplied from the source of alternating current, said demagnetizing coil operating to render said remanence ineffective while the source of alternating current is active.

6. In a system of the character described, a main burner, a pilot burner for producing a-pilot flame, an electrically operated valve for controlling the flow of fuel to the main burner, an electrically operated valve for the pilot burner, having a magnetic member and a coil for magnetizing-saidmember, a multiplier photo-electric tube having a photosensitive cathode, an anode and intermediate electrodes, said cathode being affected by the pilot flame, said tube being adapted to bev energized from a source of alternating current, the intermediate electrodes being connected to the source and having progressively higher electromotive forces, said tube supplying unidirectional current to operate the main valve only while the pilot flame is in existence, the coil for the pilot burner valve being supplied with unidirectional current derived from 'one of said intermediate electrodes, to hold the pilot burner valve open, the remanence of the magnetic member being sufficient to retain the pilot burner valve open after the coil is'de-energized, and a demagnetizing coil for the magnetic member supplied from the source of alternating current,

said demagnetizing coil operating to render said remanence ineffective while the source of alternating current is active.

7. In a system of the character described, a burner, a valve for controlling the flow of fuel to the burner, an electric circuit controlling the operation of the valve, a photo-electric tube having a photosensitive cathode and adapted to be energized from: a source of alternating current, said device serving to rectify the alternating current, and supplying the resultant unidirectional current to operate said valve, a light source affecting the cathode for controlling the flow of said unidirectional current, and condition responsive means for independently controlling said circuit.

8. In a system of the character described, a main burner, a pilot burner for producing a pilot flame, a main valve for controlling the flow of fuel to the main burner, a circuit for operating the main valve, a valve for the pilot burner, a circuit for operating the pilot burner valve, said pilot burner having a magnetic member, said pilot burner valve circuit including a coil for magnetizing said member; an electronic emission device, adapted to be energized from a source of alternating current, for supplying unidirectional current to both of said circuits, said device including means causing flow of said unidirectional current of suflicient quantity to operate said main valve only while the pilot flame is in existence, the remanence of the magnetic member being sufiicient to retain the pilot burner valve open after the coil is de-energized, a demagnetizing coil for the magnetic member and supplied from the source of alternating current, said demagnetizing coil operating to render said remanence ineffective while the source of alternating current is active, and condition responsive means for in dependently controlling the circuit for the main valve.

9. In a system of the character described, a main burner, a pilot'burner for producing a pilot flame, a main valve'for controlling the flow of fuel to the main burner, a circuit for operating the main valve, a valve for the pilot burner, a circuit; for operating the pilot burner valve, said pilot burner having a magnetic member, said pilot burner valve including a coil for magnetizing said member, a photo-electric tube having 'a photosensitive cathode and affected by the pilot flame, said tube being adapted to be energized from a source of alternating current, for supplying unidirectional current to operate the main valve only while the pilot flame is in existence, said device also supplying unidirectional current to the pilot burner valve coil for holding the pilot burner valve open, the remanence of the magnetic member being sufiicient to retain the pilot burner valve open after the coil is de-energized, a demagnetizing coil for the magnetic member and supplied from the source of alternating current, said demagnetizing coil operating to render said remanence ineifective while the source of alternating current is active, and condition responsive means for independently controlling the circuit for the main valve.

WILLIAM A. RAY.