US2362259A - Heating apparatus and starting means therefor - Google Patents

Description

Nov. 7, 1944. H. J. FINDLEY 2,362,259

HEATING APPARATUS AND STARTING MEANS THEREFOR Filed March 27. 1943 147' ran/vs Y5 Patented Nov. 7, 1944 HEATING APPARATUS AND STARTING SI THEREFOR Howard J. Findley, Shaker Heights, Ohio, assignor to Eaton Manufacturing Company, Cleveland,.0hio, a corporation of Ohio Application March 27, 1943, Serial No. 480,814

16 Claims.

This invention relates to heating apparatus of the kind embodying a fuel burning means and a thermoelectric generator, and aims to provide an improved apparatus of this kind in which novel means is employed for setting the apparatus in operation.

Another object of the invention is to provide improved heating apparatus of this kind wherein I an external source of electric current, that is a current source other than the thermoelectric generator, is temporarily utilized in setting the apparatus in operation.

A further object of this invention is to provide improved heating apparatus of the character referred to in which novel means is provided for automatically discontinuing the supply of starting current.

Still another object of my invention is to provide improved heating apparatus of this character which also includes an auxiliary device adapted to be operated preliminarily by the starting current and subsequently by current from the thermoelectric generator, and wherein novel means is employed for automatically discontinuing the starting current and shifting the operation of the auxiliary device to the thermoelectric generator.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying sheet of drawings in which Fig. 1 is a view, more or less diagrammatic in form and with portions broken away, showing heating apparatus embodying my invention.

Fig. 2 is a detached partial longitudinal sectional view of the burner tube showing the position of the vapor deflector corresponding with the cold condition of the apparatus, and

Fig. 3 is a similar'view showing the retracted position of the deflector corresponding with the hot or operating condition of the apparatus.

The heating apparatus shown in the drawing is of the kind embodying a fuel burning means ID, a thermoelectric generator ll adapted to receive heat from the fuel burning means for the generation of electricity and a propelling means l2 which operates to cause air, or other medium to be heated, to flow in heat-exchange relation to the thermoelectric generator. Heating apparatus of this type is disclosed in greater detail in my earlier applications Serial No. 445,994, filed June 5, 1942, and Serial No. 461,350, filed October 8, 1942.

The thermoelectric generator II comprises an elongated housing I3 having openings at one end |thereof for the discharge of heated air and a thermopile l5 disposed in the housing and extending longitudinally thereof. The thermopile l5 includes a tubular member l6 formed of electrically-insulating refractory material and which extends coaxially within the housing II and defines an elongated heating chamber or combustion chamber I1. The thermopile also includes a plurality of substantially radially extending thermocouples l8 connected in series and having "hot and cold" thermocouple junctions l9 and 20 disposed respectively inside and outside the heating chamber II. The thermocouples l8 extend through the wall of the tubular member l6 and are supported thereby in electrically insulated relation to each other. The space between the member l6 and the housing ll forms an annular cooling chamber or passage 22 through which the air to be heated is propelled by the device l2 for contact with the thermocouples l8 and the cold junctions 20 thereof. The outer end of the heating chamber I'I communicates with the passage 23 of an exhaust fitting 24 through which the combustion gases are discharged from the apparatus. A thermoelectric generator of the kind just described above is disclosed and claimed in my copending application Serial No. 481,450, filed April 1, 1943.

The fuel burning means l0 comprises a burner tube, 26 connected to the adjacent or inner end of the heating chamber I1 and a burner or nozzle 21 for discharging an atomized or vaporized fuel or fuel mixture into the heating chamber I! where the burning thereof heats the thermocouple junctions IS. The fuel burning means also includes a vaporizing coil 28 encircling the burner tube 26 and a hollow or chambered vaporizer 29 located between the coil 28 and the burner 21. Liquid fuel such as gasoline or other liquid hydrocarbon is supplied to the fuel burning means Hi from the tank 3| by means of a suitable pump 32 having a supply connection 33 withthe tank I and a discharge line 34 connecting the pump with the vaporizing coil 28.

The pump 32 may be of a known construction, such as a pump of the kind known as an Autopulse," and is adapted to be operated electrically in a manner to be explained more in detail hereinafter. The electric operation of the pump is automatic and is responsive to a decrease in the backpressure in the fuel line 34. To this end the pump embodies a pressure responsive switch 30 having a pair of stationary and movable contacts 30a and 30b in the pump circuit. The pump also embodies a bellows 32a which forms the pumping chamber and is connected with the fuel suction and discharge pipes 33 and 34 through suitable check valves (not shown). A magnet or solenoid 3217, when energized, causes the bellows to be expanded for the suction stroke of the pump and a spring 35 tends to collapse the bellows for forcing the fuel into the discharge line 33 when the magnet 32b has been deenergized. Whenever the back-pressure in the fuel line 34 decreases a given amount as the result of the discharge of fuel or fuel vapor through the nozzle of the burner-21 the switch 30 closes and, if current is then available in the pump circuit, the pump operates with a rapid suction stroke which is immediately followed by a gradual discharge stroke tending to restore the pressure in the fuel line. These rapid suction strokes of the pump occur intermittently and the subsequent pumplng strokes are in the nature of pulsations produced by the spring 35 tending to collapse the bellows 32a and acting against the resistance to flow encountered by the fuel in the burner 21 due to the nozzle orifice and to the vaporization of fuel in the burner.

The propelling device |2 comprises a propeller fan 36 and an electric motor 31 with which the fan is connected. This device is located at a suitable point' in the housing H, such as adjacent the exhaust fitting 24, and operates to draw cool air into the housing and to discharge the same,

through the passage 22 for delivery from the housing in a heated condition through the openings M.

The heating of the thermocouple junctions It by the flame and combustion gases directed into the chamber H by the fuel burning means It and the simultaneous cooling of the thermocouple junctions 29 by the air flowing through the passage 22, results in an electric current being generated in the thermopile l and bein made available for any desired use. One end of the thermopile may be grounded as indicated at 49 and its other end may have'a lead or conductor 4| extending therefrom.

The air propelling device I2 and the fuel pump 32 are both adapted to be operated by electric current generated in the thermopile l5 and the operation of these devices is controlled by suitable switch means which, in this instance, is in the form of the relays 43 and 44, although other forms of switch devices could be used. The relay 43, as will be presently explained in detail, also provides. a. means for connecting the apparatus with an external source of current during starting.

The relay 43 comprises a magnet 45 which is connected with the thermopile l5 by the conductor 45 so that when the heating apparatus has been put into operation it will be energized by current produced by the thermoelectric generator. This relay also includes a pair of switch arms 46 and 41 pivoted respectively at the points 48 and 49 and connected with each other by means of the insulating member 59. The arm 46 carries a contact 5| which cooperates with a stationary contact 52. The arm 41 carries contacts 53 and 54 which cooperate respectively with stationary contacts 55 and 56. A tension spring 51 acting on the switch arms 46 and 41 biases the same in a direction to close the pairs of contacts 5|, 52 and 53, 55. Energization of the magnet 45 shifts the switch arms in opposition to the spring 51 causing opening of the two pairs of contacts just mentioned and closing of the contacts 54, 56.

The relay 44 comprises a magnet 59 which is 7 located in the circuit connecting the fuel pump 32 with the relay 43 and a. switch arm 60 carrying a contact 6| adapted to cooperate with a stationary contact 62. A tension spring 63 biases the switch arm 60 in a direction to close the con tacts 6| and 62. While the contacts 6| and 62 are closed the motor 31 of the propelling device I2 is in circuit'with the thermopile l5 but, when the contacts 54 and 56 of the relay 43 are closed to supply current to the fuel pump 32 under conditions to be explained hereinafter, the magnet 59 is energized and opens the contacts 6| and 62. Such opening of the contacts 6| and 62 is preferably only of momentary duration and is for the purpose of temporarily opening the circuit of the fan motor 31 so that all of the current being produced by the thermoelectric generator can be supplied to the pump 32.

For use in starting my heating apparatus I provide a source of electric current other than the thermopile l5 and which, in this instance, is represented by the storage battery 64 and may be conveniently referred to as an external source of electrical current. Although I show this external source of current as beinga storage battery it will be understood, of course, that any suitable current source can be used. -A manually operable switch 65 is provided in the circuit leading from the external current source.

The means for starting the heating apparatus also includes an electric heating element 66 disposed in or adjacent the vaporizer 25 and an ignition element 61 in a suitable location for igniting the fuel, such as in the exhaust fitting 24, and which is adapted to be heated to incandescence for this purpose. The starting means also includes a time-delay relay 68 and a thermostatic pump control switch 69. The time-dela relay 68 is of the type comprising contacts 1| and 12 which are normally closed but adapted to be automatically opened by the flexing of a bimetal element 14 in response to the heating effect of an electric heating element 15. The contacts 1| and 12 are initially closed, or reclosed after automatic tripping of the relay, by means of the manually operable push button 13. The elements 14 and 15 are such that the flow of current through the element 15 for a predetermined interval will result in flexing of the element 14 and automatic opening of the contacts 1| and 12 to break the circuit which is controlled by this relay.

The pump control switch 69 comprises a bimetal element 11 and a pair of contacts 16 and 19. The switch 69 is located adjacent to, or in heat-conducting relationship with, the vaporizer 29 so as to be responsive to the temperature of the vaporizer. The contacts 18 and 19 are in the circuit by which current is supplied to the fuel pump 32 and they prevent the operation of the pump until the vaporizer 29 has acquired a predetermined operating temperature and also at any other time that the temperature of the vaporizer 29 is below such predetermined temperature.

When my heating apparatus is to be placed in operation it is only necessary to close the switch 65 which initiates the starting operation and results in the complete starting cycle being followed through. For the convenience of the operator the switch 65 and the time-delay relay 68 may be located at a point relatively remote from the main unit ll of the apparatus, such as on an instrument panel or on a vehicle dashboard. Th closing of the switch 65 causes current to be supplied from the battery through the contacts 5| and 52 of the relay 43 and through the time-delay relay 68 to the heating element 66 and the ignit- Since the heating apparatus is,

there will be no fuel in the vaporizer 29 at this time.

As soon as the heating element 65 has raised the temperature of the vaporizer 29 to the predetermined value necessary to close the contacts 18 and 19 of the pump control switch 89, current from the battery will then be supplied to the fuel pump 32. Since there is no back-pressure in the fuel line 34 the contacts 30a and 30b of the switch 3'0 are already closed and the pump will begin to operate. As soon as the fuel delivered by the pump reaches the heated vaporizer 29 it will be vaporized and the fuel vapor will begin to issue from the burner 21 and will be ignited by the igniter 61. The fuel vapor will also create a backpressure in the ful line 34 and the pump will thereafter Supply fuel to the vaporizer by operating with the above-described sudden suction strokes which will occur intermittently in response to variations in such back-pressure and with corresponding slow or gradual discharge strokes which tend to keep the fuel line and burner full of fuel.

As the temperature of the thermopil IS in creases toward its normal operating temperature,

current will be generated therein and will be supplied to the motor 31 to operate the propeller fan 36. Some of the current Which is generated in the thermopile l during the starting period is also supplied to the magnet 45 of the relay 43. When the voltage output of the thermopile reaches a predetermined value corresponding substantially with a desired condition or operating temperature of the heating apparatus, the magnet 45 will be energized sufficiently to actuate the switch arms 46 and 41 thereby opening the contacts 5| and 152 and disconnecting the battery 64 from the heating apparatus. The actuation of the relay 43 also opens the contacts 53, 5-5 and simultaneously closes the contacts 54, 55. This causes the circuit of the fuel pump 32' to be shifted from the battery 64 to the thermopile l5 and thereafter the fuel pump will be actuated intermittently by current from the thermoelectric generator whenever additional amounts of fuel are needed at the burner 21.

The current which is supplied to the fuel pump 32 passes through the magnet 59 of the relay 44 and each time that the pump responds to a drop in fuel pressure in the fuel line the relay 44 will be energized to open the contacts BI and 62; The opening of these contacts momentarily disconnects the motor 31 from the thermopile, as previously mentioned, so that all of the current from the thermopile can flow to the pump 32 to actuate the latter. As soon as the pump has restored the back pressure in the fuel line 34 it ceases operation and the relay 44 is thereupon deenergized which permits the contacts El and 62 to reclose and reconnect the fan motor 31 in circuitwith the thermopile l5.

If the condition of the heating apparatus should be such that the cycle above described cannot be carried through, for example, if either of the elements 66 or 61 should be burned out or if the relay 43 should fail to function to disconnect the heating apparatus from the battery, the time relay 68 becomes effective and automatically causes opening of the contacts H and 12 after a predetermined interval'to thereby prevent the battery 64 from becoming discharged and the possible occurrence of other undesirable effects. If the burner goes out for any reason during the operation of starting the apparatus th pump control switch 69 will respond to the resulting starting cycles and ultimately the time-delay relay 68 will open thereby rendering the apparatus wholly inoperative and protecting the battery against depletion. Likewise, if the burner goes out for any reason during the regular operation of the apparatus, the drop in the voltage output of the thermopile will permit the relay 43 to shift the pump circuit back to the battery 64 but this part of the circuit includes the contacts 18 and 19 of the pump control switch 69 and the opening of this switch due to the temperature drop prevents the pump from being operated from the battery unless the time-delay relay 68 is reset by intentional actuation of the button 13.

To insure prompt ignition of the fuel vapor by the element 61 during the starting operation, I find it desirable to slow down the vapor stream and create a turbulence therein. For this purpose I provide a deflector in the burner tube 26 and against which the vapor stream from the burner 21 impinges. The deflector 80 may be carried by, or may be a portion of, a strip of bimetal 8| having one end anchored to the burner tube so that when the vapor is ignited the deflector will be automatically retracted in response to the temperature increase. Fig. 2 shows the cold position of the deflector 80 before the vapor is ignited and Fig. 3 shows the deflector in its retracted position in which it remains during the normal operation of the apparatus and in which position it has substantially no effect on the vapor stream.

From the foregoing description and the accompanying drawing it will now be readily seen that I have provided novel starting means for heating apparatus of the kind embodying a thermoelectric generator. It will be seen also that the start-. ing means includes an external source of electric current and control means by which the starting of the heating apparatus can be safely and quickly accomplished without requiring the constant attention of an operator and without danger of depleting the external source of current or causing other undesirable effects.

While I have illustrated and described my improved heating apparatus in considerable detail it will be understood, of course, that I do not intend my invention to be correspondingly limited but regard the same as including all changes and variations coming within the scope of the appended claims.

Having thus described my invention, I claim: 1. In combination with heating apparatus embodying a fuel burning means and a thermoelectric generator adapted to be heated by said fuel burning means, an electrically operable fuel supply means for supplying fuel to said thermoelectric generator, an external source of electric current, and a switch-controlled circuit connecting the apparatus with said source for supplying starting current to said fuel supply means.

2. In heating apparatus of the character described, a fuel burning means, a thermoelectric generator adapted to be heated by said fuel burning means for the generation of electricity, an external source of electric current, circuit connections for supplying current from said source for initiating operation of said fuel burning means, and means automatically operable after a predetermined starting interval for interrupting the supply of current from said external source.

3. In heating apparatus of the character described, a fuel burning means, a thermoelectric generator adapted to be heated by said fuel burning means for the generation of electricity, an external source of lectric current, circuit connections for supplying current from said external source for initiating the operation of the apparatus, and a relay controlling said circuit connections, said relay being responsive to current produced by said thermoelectric generator for discontinuing the current supply from said external 4 embodying a fuel-burning thermoelectric gen erator and an auxiliary device adapted to be operated by current generated by said thermoelectric generator for supplying fuel thereto, an external source of current for operating said auxiliary device during starting of the apparatus, and means for shifting the operation of said auxiliary device from said external current source to said thermoelectric generator.

5. In combination with a heating apparatus embodying a fuel-burning thermoelectric generator and an auxiliary device adapted to be operated by current generated by said thermoelectric generator for supplying fuel thereto, an external source of current for operating said auxiliary device during starting of the apparatus, and means operable in response to the occurrence of a predetermined condition of the apparatus for automatically shifting the operation of said auxiliary device from said external current source to said thermoelectric generator.

6. In apparatus of the character described, a fuel burning means, a thermoelectric generator adapted to be heated by said fuel burning means for the generation of electricity, a pump adapted to be electrically operated for supplying fuel to said fuel burning means, an external source of electric current, and switch means for connecting said pump with the external current source for starting the apparatus and subsequently connecting the pump for electric operation from said thermoelectric generator.

7. In heating apparatus of the character described, a fuel burning means, a thermoelectric generator adapted to receive heat from said. fuel burning means and including a motor driven fan and a circuit for operating the fan by-electric current delivered by said generator, a pump adapted to be electrically operated for supplying fuel to said fuel burning means, a circuit connecting said pump with the thermoelectric generator, and a relay having an energizing coil in the pump circuit and control contacts in the fan. circuit.

8. In apparatus of the character described, a fuel burning means, a thermoelectric generator adapted to be heated by said fuel burning means for the generation of electricity, a pum adapted to be electrically operated for supplying fuel to said fuel burning means, a circuit for the pump.

and heat-responsive switch means controlling the pump circuit.

9. In apparatus of the character described, a

to be electrically operated for supplying fuel to said fuel burning means, an external source of electric current, a circuit connecting said pump and external current source, and heat-responsive switch mean controlling the pump circuit.

10. In apparatus of the character described, a fuel burning means including a vaporizer, a thermoelectric generator adapted to be heated by said fuel burning means for the generation of else- ,tricity, means for supplying liquid fuel to said vaporizer, an external source of electric current, and an electric heating element located to supply heat to said vaporizer and adapted to be supplied with current from said external source.

ll. In apparatus of the character described, a fuel burning means including a vaporizer, a thermoelectric generator adapted to be heated by said fuel burning means for the generation of electricity, anexternal source of electric current, a pump adapted to be electrically operated for sup plying liquid fuel to said vaporizer, a circuit for said pump, anelectric heating element located to supply heat to said vaporizer and adapted to be supplied with current from said external source, and switch means responsive to the heating of the vaporizer and controlling the pump circuit.

12. In apparatus of the character described, a thermoelectric generator adapted to be heated for the generation of electricity, means for heating said thermoelectric generator including a burner adapted to discharge a stream of combustible fuel, and a deflector movable to a position in front of said burner for impingement of said stream thereagainst during starting of the ing said thermoelectric generator including a burner adapted to discharge a stream of combustible fuel, a deflector movable to a position in front of saidburner for impingement of said stream thereagainst during starting of the apparatus, and temperature responsive means for actuating said deflector.

14:. In apparatus of the character described, a thermoelectric generator adapted to be heated for the generation of electricity, means for heating said thermoelectric generator including a burner adapted to discharge a stream of combustible fuel vapor, an external source of electric current, an igniter adapted to be heated by current from said external source for igniting said fuel vapor, and means for creating turbulence in the said stream of fuel vapor in advance of said igniter.

15. In apparatus of the character described, a thermoelectric generator adapted to. be heated for the generation of electricity, means for heating said thermoelectric generator including a 'bumer adapted to discharge a, stream of combustible fuel vapor, an external source of electric current, an igniter adapted to be heated by current from said external source for igniting saidfuel vapor, a deflector for producing turbulence in the stream of fuel vapor at a point in advance of saidigniter, and temperature responsive means for moving said deflector into and out of said stream.

16. In heating apparatus of the character described, a fuel burning means, a thermoelectric generator adapted to receive heat from said fuel burning means and including a motor driven fan and a circuit for operating the fan by electric current delivered by said generator, a pump adapted to be electrically operated for supplying fuel to said fuel burning means, a circuit connecting said pump with the thermoelectric generator, and a relay having an energizing coil in one of said circuits and control contacts in the other of said circuits.

HOWARD J. FINDLEY.

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