US2087399A - Oil burner - Google Patents

Description

jElly 209 1937. T. M. ELFVING ET AL 087,399

OIL BURNER Filed June 13, 1935 W Lmzew Patented july 2i), 1937 MNETED STATES OIL BURNER Thore Martin Elfving and Victor Henry Wallenberg, Stockholm, Sweden Application June 13, 1933, Serial No. 675,540 In Sweden June 15, 1932 7 Claims.

The present invention relates to vaporizing burners and has for its object to provide a burner of this ln'nd in which even heavy fuel oils may be vaporized without formation of carbon in the vaporizer. This is brought about according to the present invention by causing the vaporization of the oil to take place in the presence of free hydrogen, whereby on account of hydrogenation carbonizing is prevented while at the same time vaporization of practically all of the oil has been made possible.

The invention relates particularly to a burner in which the vaporizer communicates with an ordinary city gas line or some other line or receptacle containing a gas under a constant pressure and comprising free hydrogen, said gas being passed through the vaporizer. Such a gas mixture is in itself combustible, wherefore the burner can be started simply by lighting the gas discharged at the starting moment, which gas when burning gradually heats the oil in the vaporizer so that vaporization of the oil takes place. According as the temperature of the oil is raised the partial pressure of the oil in the vaporizer becomes higher and higher, but as the vaporizer communicates with, for example, a city gas line having a constant pressure the total pressure in the vaporizer will always remain constant. When the partial pressure of the oil is increased the partial pressure of the gas containing free hydrogen will consequently be reduced whereby an automatic choking of the city gas, which is freely discharged at the sta-rting moment, will be eected.

In the state of equilibrium the ratio between the partial pressures in the Vaporizer will be such that only so much city gas passes the vaporizer as is necessary for hydrogenation and complete vaporization. For complete combustion of one kilogram ofoil only -300 liters of city gas is required. The combustible gas supplied to the vaporizer with a constant pressure also serves as a pressure regulator, whereby a very even and easily regulated llame can be obtained. It also serves as a stabilizer, i. e. maintains a state of equilibrium between the partial pressures in the vaporizer so that if at a certain moment too little heat is supplied to the vaporizer and the partial pressure of the oil is reduced the partial pressure of the city gas will be increased, whereby a greater amount of city gas will be burnt and the supply of heat to the vaDOYZer increased so that the partial pressure of the oil will increase again.

As theV vapcrizer always has a constant pressure exceeding atmospheric pressure a sucient amount of primary air for the combustion may be supplied to the oil burner according to the invention by means of an ordinary air injector.

The invention has also for its object to utilize the source of gas under constant pressure communicating with the vaporizer for bringing about a simple continuous regulation of the vaporizing burner. As in the condition of equilibrium the ratio between the partial pressures in the vaporizer is constant and thus the amount of vaporized oil has a certain relation to the amount of city gas passing through the vaporizer, and as further the same ratio between the partial pressures should be maintained independently of the size of the flame, it is evidently possible to make the supply of oil to the vaporizer dependent on the amount of city gas passing through the same. This has also been realized in the present invention. In this way a very simple method for regulating the burner has been provided, it being possible to regulate the heat value and the operating condition of the entire burner simply by regulating the amount of gas passing through the burner. This can be eiected by the aid of known means for gas regulation, for example by means of al needle valve adapted to be regulated either manually or by means of a thermostat. According to the invention there has thus been provided an automatic vaporizing burner adaptedy to be regulated continuously by means of an ordinary gas thermostat.

According to the invention there has also been provided a vaporizing burner in which the oil gas coming from the vaporizer is given a lower coecient oi heat conduction through mixing with another gas that is permanent at ordinary temperatures resulting in a gas mixture with a reduced tendency towards condensation.

Tfhe invention will be more closely described with reference to the accompanying drawing in which Fig. l shows diagrammatically and partly in section an embodiment of a vaporizing burner according to the invention with appertaining feeding and control means; and Fig. 2 is a perspective View of the vaporizer and associated elements.

The burner proper, which is assumed to heat a hot water boiler l, consists of the burner head 2 with discharge openings 3 above which the flame 4 of the burner is formed. ToI said burner head the combustible oil vapors with admixed permanent gas are supplied through the pipe 6 from the vaporizer 5. The pipe t opens. into the ejector device 8 having a preferably adjustable orice l.

gas.

comparatively largeI evaporating surfaces` in the This ejector induces primary air through an aperture 9, Whereafter the mixture of air and combustible gases is conducted through a pipe I0 to the burner head 2. The pipe 6 from the vaporizer is preferably provided with a superheating coil I I, and the portion following after said coil is preferably insulated by means of insulation I2. The orifice 'I is preferably adjustable by means of a needle valve I3 which, in the embodiment shown in the drawing, is in turn actuated by a thermostat I4 with appertaining bulb I5. In front of the orifice I the pipe Bris preferably drained by means of a hydraulic seal I6. The. vaporizer 5 is. of the type in which the vaporization of the oil takes places. in the presence of a permanent The vaporizer is therefore provided with form of oil lledpans I 'I to which Vthe heatV neces- Ysary for vaporization is supplied partly through radiation from the external walls of chamber 23 and partly by means of the gas mixture ilo-wing through the vaporizer, it being preferable toavoid direct heating of the Voil by means of intermediate walls in direct contact with an open flame. The pans I'I are supported on flanges I9 by means of supports I8, the flanges being provided with apertures 20 for the passage of the gas. Said flanges I9 serve on the one hand as guides for the gas ow and on the other hand as heat conducting surfaces extending from the Y external wall 2I of the vaporizer, facilitating the transfer of heat to the gases flowing through the vaporizer. The vaporizer should preferably be adapted to be taken apart and is for this purpose K provided with bolts 22 which seal the outer wall the vaporizen'which is not heated, can if desired be made narrower than the upper portion and be provided with insulation 24. Oil is supplied to the vaporizer through the pipe 25 from which the oil is discharged into the upper one of the vaporizing pans I'I. Each pan is provided with an overow 26 which is so arranged that liquid from the bottom of the pan is passed by means of the overflow to the next vaporizing pan or to the collecting space 21 in the lower portion of the vaporizer respectively. To the vaporizer extendsalso a city gas line 28 provided with a preheating coil 29 from which a pipe 30 conducts the preheated city gas to the lower portion of the-vaporizer into the gas space between the lowermostvvaporizing pan and the collecting chamber for the oil. The hydrogenation may be increased by letting the city gas enter the vaporizer slightly below the oil level as indicated. The oil and the city gas are thus conducted in countercurrent through the vaporizer. When the preheated city gas` enters the vaporizer, oil isv vaporized from the oil surface in the lower portion 21 of the vaporizer whereafter the mixture of city gas and oil vapors continues upwards Vin the vaporizer through the apertures 20, the current of gas then alternately sweeping over the oil surfaces in thevaporizing pans and alternately coming in contact withthe intensely heated external wall. The gas current will in this manner-effect the supply of heat to the Vaporizing pans, said supply of heat being thus to a certain extent proportional to the amount of gas passing throughY the vaporizer.Y

greatest importance. VThe .oilfentering the va-V porizer hasY a considerably higher vapor pressure than the oil collected at the lower portion of the vaporizer. In order to obtain a complete vaporization recoursermust therefore be had tov as complete a hydrogenation as possible, which has also been realized by application of the countercur- A*rent principle.V The most suitable temperatures for obtaining hydrogenation lie for ordinary fuel oils between about 300-500 centigrade, the conditions of heating the vaporizer being, of course,

so determined that the temperature most suitable for hydrogenating the grade of oil used is always maintained Without decomposition or carbonizing occurring..v

The saturated mixtureof oil gas and city gas leaves the vaporizer through the pipe `I, then passes through the fuel heating coil II and is further conducted to the orifice 'I where primary air is added. As a result of the adding of the cold primary air the temperature of the gas mixw ture is of course reduced so that partial condensation easily might take place in the pipe `I 0 and the burner head. In order to avoid such condensation the mixed gas should be superheated and in some cases the primary air may be preheated,

and, further, all parts of the burner in contact with the oil gas should be well insulated. If',

particularly during the starting period, some con- Y densation shouldnevertheless take place the condensate will flow through the pipe Iinto the burner head proper from which it flows backto the lower portion 21 of the vaporizer through the pipe 29 forming a hydraulic seal.

The lower portion of vthe vaporizer is adapted to form a collecting vessel for the small amount of oil not Yvaporized in the lowermost vaporizing pan and for condensate. On account of the continuous vaporization of the oil in the lower portion of the vaporizer said portion will nally contain a residue having so high a boiling point that it is not any longer Worth while to vaporize the same. Said residue may either be drained off from time to time when the liquid in the lower portion of the vaporizer has risen to a certain level, or, as is shown in therdrawing, may be made to flow continuously through the pipe 30 to the containeri3l. vaporized in a vaporizer according to the invention amounts, due to hydrogenation, during normal conditions to not more than at the most 1/2 of one percent of the total amount of oil.

Instead of removing the residue by emptying the vessel 3| it is, of course, conceivable to use arrangements for continuously burning the same, the residue Ythen preferably being burnt in the Vflame proper. Y

lIn the embodiment illustrated on the drawing this has been effected by utilizing a rotating part of the gas meter 3,2Y for driving feeding Wheel 33 which from a constant oil level in the vessel 34 delivers to the funnel 35 an amount of oil pro- The. residue which cannot be portional to the amount of gas passing through 75 the meter, from which funnel the oil flows further through the hydraulic seal 3B and the pipe 25 to the vaporizer. The oil is supplied to the vessel 34 from a storage tank 31 through a pipe 38, the end of which, opening into the vessel 34, may be closed by a float controlled valve 39, which in known manner maintains a constant oil level in the vessel 3. The necessary condition for any supply of oil to the vaporizer is thus that gas must be flowing through the gas meter, and it is evident that the feeding mechanism should be so dimensioned that the proportion of city gas to oil flowing through the apparatus is the one most suitable for the operation of the burner. In

f order to be able to vary the proportion between oil and gas an adjustable bypass provided with a valve l0 may, if desired, be arranged between the gas line 4l and the gas line 28.

In the arrangement for supply of oil and city gas described above the amount of oil and gas can evidently be regulated without altering the mutual proportions simply by introducing a variable throttling device in the gas line. 1n Figure l said throttling is effected at the discharge nozzle l, as above described. A change of area of the discharge opening on account of a displacement of the needle I3 through actuation from the thermostat will evidently alter the capacity of the burner while maintaining a constant ratio between oil and gas, i. e. the same ratio between the partial pressures will be maintained in the vaporizer during all conditions and the relative economy of the burner will be the same at all sizes of the flame. The oil burner is started as an ordinary gas burner through the opening of the valve 42 in the supply line 4I for the gas. As long as the vaporizer is cold a great amount of city gas is discharged, whereby heating of the vaporizer is accelerated. In order to avoid the supply of too great an amount of oil to the vaporizer during the starting period the bypass valve l5 may preferably be kept fully open until the vaporizer has been well heated. When the vaporzer is hot an automatic choking of the city gas takes place and the bypass valve can then be restored to normal operating position.

We claim:

l. A uid fuel burning device comprising in combination a fuel oil receptacle, a burner, means for passing a current of combustible auxiliary gas containing free hydrogen through said receptacle in contact with the oil contents thereof and to the fuel burner for combustion, said oil receptacle being located relative to the burner so as to be heated by heat of combustion, so that oil vapors are developed in the receptacle in the presence of the auxiliary gas and conveyed together therewith to the fuel burner.

2. A fiuid fuel burning device comprising in combination a fuel oil receptacle, a burner, a conduit connecting said receptacle with said burner, said receptacle being located relative to the burner so as to be heated by heat of combustion, means for passing a current of combustible auxiliary gas containing free hydrogen through the receptacle in contact with the oil contents thereo-f, so as to subject the fuel oil to hydrogenation at the moment of vaporization thereof and thereby to prevent carbonization, and means for maintaining a substantially constant pressure of said auxiliary gas.

3. A fluid fuel burning device comprising in combination a fuel oil receptacle, means for supplying fuel oil to said receptacle, a burner, a conduit connecting said receptacle with said burner, said receptacle being located relative to the burner so as to be heated by heat of combustion to vaporize the oil, means for supplying a combustibile auxiliary gas containing free hydrogen to said receptacle so as to subject the fuel oil to hydrogenation at the moment of vaporization thereof, and controlling means for maintaining a substantially constant relationship between the supply of fuel oil and the supp-ly of auxiliary gas to said receptacle.

4. A fluid fuel burning device comprising in combination a fuel oil receptacle, means for supplying fuel oil to said receptacle, a burner, a conduit connecting said receptacle with said burner, said receptacle being located relative to the burner so as to be heated by heat of combustion to vaporize the oil, means for supplying a combustible auxiliary gas containing free hydrogen to said receptacle so as to subject the fuel oil to hydrogenation at the moment of vaporization thereof, and a. regulating device operated by the flow of auxiliary gas for regulating the supply of oil to the receptacle.

5. A fluid fuel burning device comprising in combination a fuel oil receptacle, means for supplying fuel oil to said receptacle, a burner, a conduit connecting said receptacle with said burner, said receptacle being located relative to the burner so as to be heated by heat of combustion to vaporize the oil, means for supplying a combustible auxiliary gas containing free hydrogen to said receptacle so as to subject the fuel oil to hydrogenation at the moment of vaporizatio-n thereof, a gas measuring device inserted in the means for supplying the auxiliary gas, and means under the control of said gas measuring device for regulating the oil supply in proportion to the measured quantity of auxiliary gas.

6. A fluid fuel burning device comprising in combination a fuel oil receptacle, means for supplying fuel oil to said receptacle, a burner, a conduit connecting said receptacle with said burner, said receptacle being locatedr relative to the burner so as to be heated by heat of combustion to vaporize the oil, means for supplying a combustible auxiliary gas containing free hydrogen to said receptacle so as to subject the fuel oil to hydrogenation at the moment of vapo-rization thereof, and means fo-r adjusting they relation between the supp-ly of fuel oil and the supp-ly of auxiliary gas.

7. A fluid fuel burning system comprising in combination a fuel oil receptacle, a burner, a conduit connecting said receptacle with said cornbustion member, said receptacle being located relative to the burner so as to be heated by heat of combustion to vaporize the oil, and means providing a flow of auxiliary gas containing free hydrogen through the receptacle in contact with the oil contents thereof, thereby subjecting the fuel oil to hydrogenaton at the moment of vaporization.

VICTOR HENRY WALLENBERG. THORE MARTIN ELFVING.

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