US1860958A - Method and apparatus for burning liquid fuels - Google Patents

Description

May 31, 193? w. 17 SALLEE 1,360,953

METHOD AND APPARATUS FOR BURNING LIQUID FUELS Original Filed Dec. 3, 1929 3 Sheets-Sheet l INVENTOR ATTORNEY y 1932- w. l. SALLEE 1,860,958

METHOD AND APPARATUS FOR BURNING LIQUID FUELS Original Filed Dec. 3, 1929 3 Sheets-Sheet 2 INVENTOR W. I. SALLEE May 31, 1932.

METHOD AND APPARATUS FOR BURN ING LIQUID FUELS Original Filed Dec. 3, 1929 3 Sheets-Sheet 3 INVENTOR ATTORNEY Patented li/iay 31, 11932 WEBSTER I. SALLEE, OF CLEVELAND, OHIO METHOD AND APPARATUS FOR BURNING LIQUID FUELS Original application filed December 3, 1929, Serial No. 411,279. Divided and this application filed.

February 19, 1930.

, This invention relates to a method and apparatus for burning liquid fuels such as low grade oils and tars efficiently, permitting the use of such fuels in sand driers, metal treating furnaces and the like, and is a divisional application of my copending application, Serial No. 411,279, filed Dec. 3, 1929, On a drying apparatus.

"Effective combustion of such fuels res quires that the oil be atomized, thoroughly mixed with a conveying medium, and burned before the globules have settled out from the mixture.

The methods now employed contemplate atomizing the fuel by a fuel gun or ejector which is arranged to discharge directly into the combustion chamber of a drier or furnace, depending on the radiant heat from the relatively large combustion chamber to vaporize and ignite the fuel.

\ Incomplete and ineflicient combustion of the fuel results from these methods, causing carbonaceous deposits'on-the walls of the combustion chamber and loss of fuel due to suspended carbon and combustible gases passing out of the furnace with the products of combustion.

In sand driers and heating equipment in which the products of combustion come in contact with the material being treated, a

clean flame and clean products of combustion are necessary.

It is therefore an object of my invention to reduce the costs of heating with liquid fuels by obtaining efficient combustion thereof and effective application of the heat obtained.

Another object of my invention is to produce a clean flame and eliminate the necessity for expensive stacks, and accomplish these results by the use of relatively inexpensive and easily obtainable equipment.

Another object of my invention is to proride an apparatus for burning liquid fuels which, even when completely cold, may be heated to a temperature sufficient for efficient operation within a very few minutes, thus permitting closing down out of working hours and eliminating the necessity of continuous heating or operation.

Serial No. 429,519.

More specific objects of my invention include efficient production and effective control of heat from liquid fuels through a very wide range of volumes and temperatures.

Another specific object of my invention is to eliminate destructive concentration of heat on any part of the combustion chamber of afurnace or drier and to eliminate large radiation losses, by obtaining combustion evenly distributed over the most effective areas.

Another object is to preheat the fuel economically and control the size, and shape of the flame.

Other objects and advantages of my invention will become apparent from the following description, in which reference is made to the drawings by the use of numerals.

In the drawings:

'Fig. 1 is a side elevation of an apparatus suitable for carrying out the method of my invention, portions being shown in section for clearness.

Fig. 2 is an end elevation of the apparatus illustrated in Fig. 1.

Fig. 3 is an enlarged longitudinal sectional view of the oil atomizing gun and register illustrated in Figs. 1 and 2.

My process contemplates vaporization and partial combustion of an intimate mixture of air and oil by radiant'heat, While the mixture is retained centrally of an enveloping quantity of air under pressure, the movement of the, burning and vaporized oil and the enveloping air stream into a second enveloping air stream, wherein combustion is completed.

An apparatus which I have found efiicient for carrying out this process includes a primary vaporizing chamber 1, closed at one "end by a plate 2 having an opening to receive an air register 3, in which is mounted an oil atomizing gun 4 adapted todischarge a stream of atomized fuel into the chamber 1. The other end of this vaporizing chamber is contractedto form a cone-like head 5 and a nozzle 6, through which the heating medium that is, the burning mixture of fuel and air of the vaporizing chamber 1 maypass through a suitable port 7 into a combustion chamber of a furnace or drier.

The vaporizing chamber 1 is preferably a cylindrical shell, lined with refractory material, such as fire brick 8, and is relatively covered with asbestos or other insulating material. Thus high temperatures suliicient to cause almost instantaneous vaporization of low grade oils are brought in closer proximity to the stream of atomized fuel and damage to the apparatus from high temperature as well as heat losses by radiation are eliminated.

To introduce air and a spray of atomized oil into this chamber, the oil gun and air register fully described in Letters Patent of the United States 1 0. 1,680,455, with certain modifications to meet my requirements, have proven satisfactory and are here shown for purposes of illustration. Any efiicient atomizing gun may be used however.

As there described, the oil gun consists of a hollow casing 10, in which is mounted a spinner or cup 11, rotatable about a hollow shaft 12 on suitable bearings 13. An air turbine 14 is provided on the spinner to rotate it at high velocity as air is forced into the casing 10 from a fan or pump 15 through a conduit 16. The/volume of air supplied is controlled by a valve 17. Oil is caused to flow from a reservoir to a pump 18, which forces it under low pressure through a conduit 19 passing into the casing 10 and joining the hollow shaft 12 through which the oilis discharged into the inside of the spinner 11.. The spinner 11 imparts a rotary motion to the oil and discharges it in the form of a whirling sheet, conical in form. In the discharge end of the spinner 11 are a number of inturned teeth which strike the. oil as it is thrown out of the spinner, imparting additional rotary motion thereto, and mechanically beating the oil into a spray of small globules.

The air stream, after passing the turbine 14, passes out of the casing10 between the,

casing and the spinner 11. Vanes 20 are provided Within the casing near the discharge end to cause the air stream to'leave the casing with a spiral motion, the direction of .rotation being opposite to that of'the oil stream so that the oil strikes the air at an abrupt angle, and insures more complete atomization and mixture.

As described in said application, additional air is supplied through an air register 3. Radial vanes 21 mounted on rocker shafts 22 in the register 3, are provided to control the direction and shape of the air steam passing out of the register. The rocker shaft-s 22 are pivotally mounted in a collar 23 about the gun casing 10 at their inner ends. The outer ends pass through openings in the register casing and are bent over to engage notches in a ring 24 loosely mounted on and rotatable about the register casing. By rotating the ring 24, the rocker shafts 22 rotate about their axes concurrently, changing the angle of the vanes 21 with their open positions, which are parallel to the axis of the register.

The volume of air drawn through the register 3 is controlled by an end plate 25 slidable axially of the register 'on supporting rods 26 to increase ordecrease the opening between the end plate and register.

- For my purposes, I increase the length of the supporting rods 26 and oil gun 4 and move the end plate 25 to its withdrawn position on the lengthened rods. Between the end plate and the register 3 I place a sealed even pressure chamber 30 opening into the register'3. 'Air under pressure is supplied to the even pressure chamber by a fan 31, through a suitable conduit 32. A number of shutters 33 are provided at the entrance of the even pressure chamber 3 to control the volume of air entering it. These shutters may be provided with rocker-shafts 34 extending through the walls of the even pressure chamber and bent over at their outer ends to engage notches in slidable lever 35, the movement of which changes the size of the air passage into the even pressure chamber by changing concurrently the angular position of the shutters.

As shown, it is desirable to make the even pressure chamber much larger than the opening of the register 3, so that eddy currents will be broken upand a direct and even flow of air into the register will be obtained. By this arrangement the shape and volume of the air stream emanating from the register can be'accurately controlled. Either a ,direct or swirling stream of air may be obtained, and the direction of rotation of the swirling stream caused to be clockwise or counterclockwise, by rotating the vanes 21 about their respective shafts 22 to set them at predetermined positions relative to the incoming air stream.

As described, the mixture of oil and air entering the vaporizing chamber has a spiral motion. The large volume of air supplied through the register builds up a pressure within this chamber and envelopes the burning mixture from the gun, retaining it approximately centrally of the combustion chamber.

A rapid mixture of this air'with the oil spray may be obtained by turning the radial vanes 21 so that the column of air from the register rotates in a direction opposite to that of the spray to increase the angle of impact of the two. The flame can be lengthened'by admitting a direct current of air from the register By rotating this air column in the same direction as the flame, still further control of the shape of the flame can be obtained.

Since the vaporizing chamber is relatively small, it can be heated within a period of a very few minutes to a temperature which will cause almost instantaneous vaporization of the atomized fuel. This eliminates the necessity of continuous heating and renders economical. stopping operation of the burner when the drier or furnace is not in use. Further, by using a comparatively small chamber, the heated chamber walls provide a source of radiant heat close to the stream of atomized oil. Thus the radiant heat in close proximity causes rapid and complete vaporization of the oil while suspended in the air. Likewise, due to the limited size of the vaporizing chamber and large volume of air introduced therein and expansion of the vaporized oil, a pressure is built up, forming an envelope of air about the oil stream, which retards the movement of the oil globules out from the atomiziug air stream and prevents their contact with the walls of the vaporizing chamber.

Further, the surrounding envelope is heated and mixes readily with the vaporized oil.

A burning and well mixed volume'of gas from the oil and air, surrounded by a large quantity of preheated air is obtained in this manner. The pressure of the mixture is transformed into velocity by the contracted nozzle of the chamber.

I now direct the burning gases and the enveloping air into any furnace or apparatus in which it is desired to use it. I do this by providing at the entrance of the combustion chamber of the furnace or drier a fire tube 7 of greater diameter than the nozzle 6, having at its entrance end a suitable bell 41 with an inner contour substantially complementary to the conelike head 5 of the vaporizing chamber. The fire tube shown as circular in cross section, may be of any desired shape, depending upon whether a column or flattened sheet of flame is desired. This arrangement forms an air passage 42 between the combustion chamber and the bell, through which additional air may be drawn into the fire tube and combustion chamber of the furrface.

This air prevents overheating of the fire tube and the combustion chamber of the fur nacewadjacentto the discharge end of the nozzle, and retains the flame in a position spaced from the walls of the combustion chamber. The heat thus removed is recuperated as the air thus heated unites more rapidly with the gases and insures complete and efficient combustion of the fuel and gases while in the furnace combustion chamber.

The air thus drawn in also forms a second surrounding envelope of air and prevents the gases or any suspended oil therein from com ing into contact with the walls of the combustion chamber of the furnace.

Due to the pressure and swirling motion in the vaporizing chamber, the gases and miX- ture passing therefrom form into a spinning column of flame, the shape of which can be accurately controlled. This flame and mixture being composed of light gases, retains its shape and position near the axis of the column of indrawn air, which likewise has a spiral motion, due to the action of the gases as above described. Radial vanes, which may be in form and function similar to those in the register, may be provided within the annular opening to control the direction of rotation of this air stream, and consequently the shape of flame.

The vaporizing chamber may be moved axially of or offset from the axis of the fire tube and bell, so as to change the size and shape of the opening between the bell 41 and conelike head of the vaporizing chamber, thus controlling the amount of air admitted, and the direction and location of the flame.

In order to obtain these positions the legs of the vaporizing chamber may be made in sections such as 418 and 49, and connected by adjusting screws 50. Each of the legs may be provided with a suitable bearing plate such as 52 preferably resting on the floor but not attached thereto, so that lateral movement of the vaporizing chamber is possible.

To preheat the oil'when the apparatus is started, I provide an electric heating coil 45 about a portion of the oil feed conduit. Since preheating is at all times desirable, I may provide several turns of the oil feed conduit about the vaporizing chamber as at 46, enclosing the coil in a suitable housing 47. As soon'as the vaporizing chamber is heated, the oil passingthrough the coil of conduit will be heated sufficiently so that heating by the electric coil may be discontinued.

It should be noted in this connection that while I have described my method and apparatus as utilizing air for various purposes, a combustible gas may be used for part or all of the purposes mentioned as to air and will produce very satisfactory results economically. The use of gas instead of air is especially desirable in heating furnaces, as it reduces the amounts of oxygen introduced into the furnace.

Experience has proven that without varying the size of the vaporizing chamber or any of the parts of the apparatus, efficient comstream of atomized fuel and air into a con fined space 111 the presence of a source of radiant head sufiiclent to vaporlze and ignite said stream, passing a forced blast of secondary air into said confined space and around the burning stream and discharging the burn-- vaporize and ignite said stream and concurrently blowing an oppositely rotating air stream about said first mentioned air and fuel stream and discharging the resultant mixture from said confined space at high Velocity, passing additional air about the stream so discharged after it leaves said confined space.

3. A method of burning liquid fuel which comprises atomizing the fuel and concurrently mixing with the fuel a stream of air, and directing the resultant stream of air and fuel into a confined space in the presence of a source of radiant heat sutficient to vaporize and ignite said stream of air and fuel and concurrently blowing a second air stream into said confined space and about said first mentioned fuel and air stream and discharging the resultant mixture from said confined space at high velocity with a swirling motion whereby an elongated forcible swirling column' of flame is formed, and preheating the fuel by conduction of heat from said burning stream before atomizing said fuel.

4. A method of burning liquid fuels which comprises discharging the fuel with a retary motion into a confined space in the presence of a source of radiant heat sufficient to rently mixing the fuel with a rotating stream of air and directing the resultant rotating stream into a confined space in the presence of a source of radiant heat sufficient to vaporize and ignite said stream and concurrently blowing an oppositely rotating stream about the resultant stream of fuel and air, discharging the resultant burning mixture from said confined space at high velocity and signature.

- WEBSTER I. SALLEE.

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