US2657744A - Apparatus for vaporizing liquid fuel - Google Patents

Description

Nov. 3, 1953 IA. B. NEWTON APPARATUS FOR VPORIZING LIQUID FUEL Filed sept. 29, 194s 1N VEN TOR.

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Patented Nov. 3, 1953 UNITED STATES rOFFICE APPARATUS FOR VAPORIZING LIQUID FUEL Application September 29, 1948, Serial No. 51,729

2 Claims. 1

This invention relates to liquid fuel burner systems in which a lifmid fuel is converted to a gaseous state for burning in a conventional gas burner and more particularly to improved means for converting the liouid fuel to a .gaseous state.

Mv cooending application. Serial No. 655,722, filed March 20. 1946, now abandoned, discloses a device for converting liquid fuel to a gas before burning thereof. The present invention constitutes an improvement thereover. It is a well known phenomenon that when certain temperatures are attained in metals their magnetic properties diminish and the temperature at which this occurs is commonly referred to as the Curie point. It is an object of this invention to utilize this phenomenon to maintain the temperature of the device which vaporizes the oil within the desirable temperature range between temperatures which will produce full vaporizing of the oil and temperatures which will produce carbon. A vaporizing plate is maintained at the desired temperature and oil is brought in contact therewith for vaporization.

It is a further object of the invention to avoid local overheating oi portions of the vaporizing plate as sometimes occurs with a thermostatically controlled plate of the type described in my copending application Serial No. 655,722.

It is an additional object of the invention to reduce the electric current consumption of devices of this type. In the device to be described herein only that portion of the plate 4which is cooled by the contact of liquid oil will be heated. The heating in this device is, of course, accomplished by induction rather than by resistance heating which would heat the entire plate.

The foregoing and other objects and advantages of the present invention may be ascertained from an inspection of the following specification taken in connection with the accompanying drawings wherein like numerals refer to like parts throughout.

In the drawings,

Fig. l discloses a schematic representation of the invention; and

Fig. 2 illustrates a control circuit.

A heating appliance i@ such as a furnace, boiler, water heater or the like, includes a heat exchanger Il connected to a flue i3 and having a combustion space l2. Mounted within the combustion space l2 there is provided a gas burner I4 comprising a distributor space l5 and orifices I6. Gas under pressure is injected into the burner through a Venturi tube l1 and entrains therewith primary air of combustion. It is to be appreciated 'that the present invention may be applied to any operative form of burner having gas introduced thereinto under pressure. The gas is introduced into the inlet of the Venturi device through a nozzle I8 communicating with the interior of a housing I9 defining a pressure Vaporizing chamber having a fairly massive floor 2i] adapted to be heated as will presently appear. Liquid fuel is introduced to the interior of the housing i9 and drips upon the floor 20 through a tube 25, preferably provided with a liquid trap double-U bend, extending from a liquid fuel metering device Z5. A transformer 29 and lstack temperature sensing device 3&1 are schematically illustrated in the relative positions that they would normally occupy. The iloor 2Q is made of a magnetic material so that its `Curie point is above the temperature at which the liquid fuel will vaporize and below the temperature at which carbon will be produced. Means will be described herein for heating iioor 2B by induction.

Referring to Fig. 2 there is disclosed a power line having a first primary transformer winding 35 anda second primary transformer winding 36 connected in parallel. ll'he Winding 35 pro- Vides reduced voltage to a control circuit through secondary windings 31. One end of the windings 31 is connected to a thermostat contact 323 adapted to contact a Vtemperature sensing device 3S, such as a bimetallic bar, when heat is desired in the room or other space to which heat is to be supplied under automatic control. Bar 39 is connected to a wire 4t. A contact 43 is provided and makes contact with a contact carried on a rotatable arm di attached to the stack temperature sensing device 3@ which comprises a thermostatic element such as a bimetallic spiral 55 adapted to rotate a rod it clockwise upon rise of temperature within the iiue i3.

A wire 4! is connected to a contact til extending through the wall of a glass bulb El mounted upon a second arm 52 attached to the rod de for rotation in a clockwise manner upon rise of temperature in the flue I3. In the position illustrated the bulb 6| is tipped toward the left and a small quantity of mercury 53 contained therein thus bridges the gap between contact Se and a second contact til extending through the wall of the tube. Contact t4 is connected by means of a Wire S5 to a temperature sensing element @6 preferably located adjacent floor 25B and adapted to Contact a iixed contact 61. The Contact lEl is connected to a wire 58 leading to a heater element t9 positioned within the fuel metering device 26, the opposite end of the resistance heater 69 being connected by wire 19 to wire 54 leading back to the secondary winding 3l'. Thus, when heat is required and thermostat 39 makes contact the heater 69 will be energized if thermostatic element 69 makes contact and bulb iii has not rotated far enough clockwise to cause 'the mercury 93 to run to the right end of the bulb E I.

Contact iI is also connected by a wire 42 to the contact llt. When there is no combustion occurring contact 43 and arm lill are engaged as illustrated, but upon a rise in temperature within the flue sufllcient to indicate that combustion has taken place arm lill will be rotated away from contact t9. The arm ill connects contact 43 to wire 50 leading to the solenoid 0f a switch 5I adapted to close the parallel circuit leading to primary winding 3S. As soon as thermostat 39 calls for heat the secondary winding 52 will be energized to cause a spark at the spark device 53 located adjacent the orices IE of the gas burner so that an ignition spark would `be provided in readiness for gas issuing from the burner. From the solenoid oi the switch device 5i a wire tilt leads back to the transformer winding 3l.

The secondary windings 3l are connected to a wire 'i5 leading through a condenser i6 to an induction coil il positioned adjacent the oor 29. When current of the proper frequency is admitted to coil il iioor '29 is heated by induction. Coil il has its opposite end connected by wire 'F9 to the wire 5ft leading back to transformer The coil "il upon being energized raises the temu perature of any portion of floor 2U having a temperature below the Curie point oi the metal therein. When the Curie point is reached the heating automatically discontinues as an incident to the diminishing magnetic properties of the heated metal. The hot floor 29 vaporizes fuel dripping thereon. rlhe vaporized fuel is maintained under pressure by the head in tube 25 and escapes through the nozzle i8 into the gas burner where it is consumed in accordance with known principles of gas combustion. The liquid fuel is prevented from flowing into the chamber i9 until slightly after a predetermined minimum temperature is reached. When the predetermined minimum temperature is reached element 96 closes with contact 6'! and resistance 59 thereupon becomes energized. The resistance 99 heats a bimetallic bar 89 connected by a rod SI to a valve device iii adapted to permit metered flow of liquid fuel into the tube 25. rIvhe reaction of element @il is preferably very rapid so that metered quantities of fuel will flow shortly after element 96 closes the circuit to element 69.

Contact 6l is also connected to wire 85 leading to a heater 99 adjacent the thermostatic element 3d, the other end of which is connected by means of wire Sl' to wire 54 leading back to a secondary winding Si, so that heater B6 is energized simultaneously with heater 69. The eiTect of heater 85 is so calculated as to raise the closing temperature of the element 39 several degrees above the temperature for which it is set so as to prevent operation of the burner for mild fluctuations in temperature since the thermostat will open immediately after closing and remain open unless there is a continued demand for heat, and likewise will open when the room temperature is a few degrees lower than the thermostat setting so as to prevent over-supply of heat. The heater 95 thus provides means for modulating or eveningthe heat supplied to a dwelling or the like, and operates in accordance with well-known principles.

The vaporizing chamber having been raised by energization of heater 'VI to a degree sufficient to instantaneously vaporize the fuel when the metered iiow of fuel occurs the fuel flashes into gas and is ignited at the orifices IG. Thus When thermostatic control t9 rmly calls for heat there will first of all be supplied an igniting spark at spark gap 53. Combustion will cause the temperature within the flue I3 to raise suiciently to open the circuit at contact 43 thus cutting olf the ignition spark. If the temperature in the nue passes a predetermined high limit the bulb 6I will rotate beyond the vertical and open the circuit to the resistance 69 thereby causing cessation of fuel flow. Coil l1 will remain energized thus causing the Vaporizing chamber to rise in temperature to a predetermined high limit at which time the magnetic properties of the floor 29 will diminish and further inductive heating will not be possible. If, on the other hand, the room temperature or the temperature of the boiler or other device indicates that heat is no longer required element 39 will open the entire control circuit regardless of the position of the bulb Si or the temperature of the vaporizing chamber I9 and the metering device will cease operating.

The switch is operated by a rod 99 mounted upon a bucket 9i carried by a lever 92 pivoted at @t and countenbalanced by a spring 94, the device being located in the closed chamber 28 in such position as to cause the bucket 9| to receive overiow from the chamber I9 through the overilow tube 2l. rlhus if the chamber I9 over flows, indicating failure of the system to operate satisfactorily, the switch 55 will open all of the control circuits and no further operation can occur until a serviceman corrects the diiTiculty.

Switch 55 is also in series with the switch 5S which provides an ignition failure safety device. Switch 5B is normally closed and is adapted to be opened by a time delay relay I9@ connected across the transformer winding .il through wires IBI and I92 so that it will be energized immediately upon closure of thermostatic element 39 and will open switch t to render the system inoperative a predetermined interval of time after current is supplied to the control circuit and heaters, provided combustion fails to take place. If combustion takes place a thermo-electric generating device I93, which is so positioned as to generate a current when there is a flame at the burner I4, will Cie-energize relay I9!) through means of a switch Hill operated by a solenoid |05. `Other forms of delayed action devices such as clock-motors and the like may be substituted for the relai7 Idil, and other forms of switch actuating devices such as electronic tubes adapted to be energized upon combustion may be substituted for the thermocouple device IGS, without departing from my invention.

A feature (not shown) of modern stack switches is that arms 44 and 62 may be connected to rod 45 through the medium of slipclutch devices, and are limited in movement by suitable stops. Thus arm 44 may move through an arc representing a rise of 50 degrees and then will be held against further rotation, so that upon a temperature drop of 50 degrees, ignition will be reestablished. Also arm 62 will be constrained to move in an are sufficient to cause breaking of the circuit at the desired temperature regardless of the extent of further rotation of rod 46. and

may reestablish the circuit after a temperature drop of, for example, 50 degrees.

Having illustrated and described a preferred form of my invention I claim all such modications thereof as come within the scope of the appended claims.

I claim:

l. Apparatus for vaporizing liquid fuel preparatory to combustion in a burner of the type adapted to burn a gaseous fuel introduced thereinto under pressure comprising a closed container in which vapor pressure may build up, said container having a ioor therein formed of magnetic material and having a nozzle forming an outlet through which the resulting vapor is discharged solely by the vapor pressure built up in said container, a liquid fuel metering device operable to deliver liquid fuel to said container and into contact with said floor, a source of electric energy and an electric coil connected to Said source and located in proximity to said floor and operable when energized to subject said oor to a magnetic field and to inductively heat said floor until it has attained a temperature corresponding to its Curie point.

2. A vaporizing device adapted to deliver gas under pressure to the inlet of the gas burner of a heating appliance comprising a closed container having a floor formed of magnetic material which loses its magnetic properties at a predetermined temperature and a nozzle communicating with the interior of said container and adapted to deliver gas to said gas burner inlet, the gas being discharged from said container through said nozzle solely by vapor pressure built up in said container, a liquid fuel metering device, tubing connecting said liquid fuel metering device to said container above said floor to accommodate the dripping of fuel on to said floor and electrical means for heating said floor by induction.

ALWIN B. NEWTON.

References Cited in the le of this patent UNITED STATES PATENTS

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