US2068441A - Oil burning device - Google Patents

Description

Jan. 19, 1937.

'8. VALJI- IAN OIL BURNING- DEVICE Filed June 17, 1952 2 Sheets-Sheet 2 I0 4 3 o o J a a 4 w 0 7 W 1 6 7 J 8 I 4 7 J 4 2 4 J o w f Peiented Jan. 19, 1937 2.008.441 g on. BURNING DEVICE 1 Ben Valjean, Lansing, Mich asslgn'or it Motor Wheel Corporation, Lansing, Mi h tion at Michigan 0 u a corpora- Application June 17, 1932, Serial No. 617,802

Claims.

This invention relates to oil burning devices and more particularly to devices of that charac-.

ter suitable for practicing the process of combustion wherein a premixture of oil vapors and air is formed in a premixing chamber and the premixture thus formed is subsequently burned in a combustion chamber in the presence of an adequate amount of combustion supporting air.

The general object of. this invention may be the provision of an oil burning device of the premixing type wherein relatively perfect and noiseless combustion of fuel oil is obtained without the escape to the fiues of any unconsumed air or oil vapors. This object is accomplished, in part, by causing a uniform mixture of oil vapors and air to pass at a relatively high velocity into a combustion chamber where combustion supporting air is introduced into the mixture uniformly in the same direction as the flow of the mixture and at substantially the same or a slightly greater velocity.

One of the more specific objects of the invention is the provision or an oil burning device adapted to complete combustion in a localized area and in substantially a horizontal plane.

This object is attained by causing the premixture to pass into the combustion chamber with a gyratory or spiral motion. Combustion supporting air is projected into the swirling mixture in a manner whereby to accentuate the horizontal or gyratory movement of the mixture. Combustion accordingly occurs in a zone of limited vertical extent.

A further object of the invention is the provision in an oil burning device of the premixing type of means for automatically controlling the rate of vaporization of fuel oil to correspond to the amount of air available for mixing with the same. This is accomplished by confining the fuel within the premixing chamber whereby to limit the surface area thereof and then passing the air utilized for forming the premixture over the confined fuel.

Still another object of the invention is the provisio'n of an oil burning device wherein natural draft is utilized to'produce a rotary or gyratory flame. This is accomplished by introducing the premixing air into an annular passageway containing vapors through holes inclined horizontally at an oblique angle to the wall of the chamber whereby the air circulates about the annular passageway forming a premixture of oil vapors and air which passes upwardly into a combustion chamber with a swirling motion.

Combustion supporting air is admitted to the combustion chamber through holes inclined similarly to the holes in the premixing chamber whereby the swirling motion of the premixture is to some extent converted to a gyratory motion and combustion occurs in a zone of limited ver tical extent.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the fea= tures of construction, combination of elements and arrangement of parts, which will be exem plified in the construction hereinafterset forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the 15 nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Figure I is a perspective view of an oil buming water heater embodying the present invention with a portion of the outer casing cut away to show the relation of the internal parts.

Figure II is a perspective view of a premixing chamber utilized in combination with the oil burning device shown in Figure I as embodying the present invention with parts cut away to show the construction and arrangement oi. the interior of the chamber; and

Figure III is a top plan view of the premixing chamber shown in Figure 11.

The oil burning water heater shown in Figure I embodying a preferred form of the present invention consists of a cylindrical outer casing ill spaced from a cylindrical inner casing it by a quantity of insulation material I3. The cylindrical casings Ill and l l are secured to abuttom wall it in any suitable manner as by welding the upturned peripheral flange it of the bottom wall to the lowerextremity of the outer casing iii. The upper extremity of the inner casing H is closed by a cover 16 provided with a downwardly extending peripheral flange ll whereby the cover is secured to the casing M. The upper extremity of the outer casing it is 5 flanged as indicated at l8 and a circular cover it is secured to the casing l0 within the flange E8; The space between the covers l6 and i9 is filled with insulation material it.

An annular ring 20 secured to the inner casing ll adjacentthe lower extremity thereof provides, means for supporting a premixing chamber or burner chamber 2|, the lower extremity of which is preferably spaced slightly above the bottom wall it. The premixing chamber 26 is Gil "chamber 2|.

formed with an outwardly extending annular flange 22 whereby the premixing chamber is secured to the ring 20. A combustion chamber 23 comprising a cylindricalvertical wall 24 and a top wall 25 is positioned above the premixing chamber 2| and in open communication therewith. The lower extremity'of the cylindrical wall 24 is seated upon the annular flange 22 of the premixing chamber 2| whereby to support the combustion chamber over the premixing chamber. Suitable means, such as stove cement, is utilized for forming a substantially airtight joint between the lower extremity of the vertical combustion chamber wall 24 and the upper extremity of the premixing chamber 2|..-

Four exhaust flues 26 provide means for the escape from the combustion chamber of the prodnets of combustion. The exhaust fluesare arranged with their lower extremity secured within openings provided for that purpose in the top wall of the combustion chamber 23 and extend vertically withinthe chamber formed by the inner casing. The upper extremity of the exhaust flues 25 communicate with openings formed in a circular plate 21 which is positioned within the casing adjacent the upper extremity thereof. The plate 21 is provided with an upturned peripheral flange '28 whereby the plate is secured to the inner casing member l as by welding, for example. The exhaust flues 26 deliver the products of combustion from the combustion chamber to a compartment 30 formed between the circular plate 21 and the top wall I8 of the" casing The products of combustion delivered to the compartment 30 escape to a chimney or outlet flue, not shown, through the exhaust pipe 3|.

The plate 21, the casing H, the top and side walls of the combustion chamber 23, and the annular ring 20 secured to the casing define a chamber 29 adapted to contain the water to be heated. Water is delivered to the chamber 29 through a supply pipe 32 and is withdrawn from the chamber through the pipe 33. It will, of course, be understood that the joints between the various members forming the water chamber 29 are suitably treated to prevent the escape of water from the chamber 29 other than through the outlet pipe 33.

Fuel oil is delivered to the premixing chamber 2| through a fuel inlet pipe 34 from a control device 35 connected to a fuel supply tank, not shown, by pipe 36. Suitable mechanism, not shown, is contained within the control device 35 for regulating the flow of fuel oil to the premixing A conventional thermostat, responsive to the temperature of the water contained within the chamber 29, may be associated with the control device 35 for operating the mechanism regulating the flow of oil to the premixing chamber 2|. A plunger rod 31 is preferably associated with the fuel inlet pipe 34 whereby to clean the same as occasion requires. An automatic safety device comprising a bimetallic bar, not shown, having one extremity positioned within the premixing chamber 2| and its other extremity associated with the mechanism for controlling the flow of fuel to the premixing chamber, is positioned within the conduit 38 extending between the control device 35 and the premixing chamber 2|.

The control device 35 is preferably designed to permit a limited quantity of fuel oil to flow into the premixing chamber 3| at all times whereby i-n nrr'wide fuel for a pilot fire. It should, of

course, be understood that any suitable ignition mechanism may be utilized since the details of such mechanism comprise no-part of ,the present invention.

When the mechanism controlling the flow of fuel to the premixing chamber through the fuel inlet pipe 34 is actuated to permit a flow of fuel suflicient for the normal operation of the burner and the fuel is ignited within the premixing chamber, the heat generated by the resulting combustion causes the liquid fuel entering the combustion chamber to vaporize. The rate of vaporization of the fuel may be facilitated by causing the premixing air entering the premixing chamber through the air inlet openings 39 formed in the lower portion of the wall thereof to pass over the liquid fuel. The air admitted through the openings 39 mixes with the oil vapors generated within the premixing chamber to form a premixture of oil vapors and air.

The exact nature of the premixture thus formed is not definitely linown, although it is believed to be a purely .physical mixture of air and oil vapors. However, certain authorities have expressed a belief that a chemical reaction takes place between the oxygen contained in the air and the constituent elements of the fuel oil. Regardless of the reaction which occurs between the air and the oil vapors it is known that where the quantity of air admitted to the premixing chamber through the inlet openings 39 is less than the total amount of" air required for the complete combustion of the oil vapors generated within-the premixingchamber by-reason of the natural draft created through the'outlet flues. It should; of course, be understood that the lower portions of the casings l0 and H below the annular ring 20 are per-' forated in a suitable manner to permit the entry of an adequate quantity of air into the space surrounding the premixing chamber 2|. As the premixture passes from the premixing chamber 2| into the combustion chamber 23 combustion supporting air is introduced into the premixture through the air inlet openings 40 formed adjacent the upper extremity of the premixing chamber 2|. At the maximum oil feed, combustion occurs within the combustion chamber 23, as illustrated diagrammatically by the flames 4|;

Thefeatures of construction and operation of the device shown in Figure I'thus far described are substantially identical to those found in the prior art. However, as shown in Figures II and III, the specific details of construction of the present oil burning 'device differ in several important respects from the prior art structures.

The premixing or'burner chamber 2| is preferably, although not necessarily, formed of cast metal and is provided with a plurality of circumferentially spaced apart vertically extending external ribs 42. The ribs 42 are preferably hollow and of triangular shape in cross section. The upper extremity of the wall is formed with an internal shoulder 43 and with an external collar portion 44 positioned immediately below the outwardly extending annular ring 22. A plurality of circumferentially spaced apart vertically extending ribs .45 similar to the ribs 42 are formed in the collar 44.

2,068,441 aligned with the ribs 42 butma'y lie in a planeintermediate the ribs 42.

The base of the premixing chamber 2| is formed with a raised central portion 46 in the shape of a cylinder arranged in concentric relation to the vertical walls of the chamber. This central portion is preferably formed integrally with the base and may terminate slightly below the top of the chamber 2| or as here shown may terminate just above the bottom wall. A removable cylinder-like member 41 preferably formed of cast metal and provided with a plurality of horizontally spaced apart outwardlyextending flanges or baiiie members 48 is positioned upon the central portion 46 when it terminates as here shown adjacent the bottom wall. The cylindrical member 41 is formed with a closed. upper extremity 48 and the lower extremity thereof is closed by the raised central portion 46 of the bottom wall of the premixing chamber. A pair of aligned openings are formed in the central portion 45 and the closed upper extremity 49 of the cylinder 41. A vertical tube 50 is secured within these openings with its upper extremity preferably extending slightly above the wall 49. A removable cap l spaced slightly away from the top of the tube 50 is secured within the upper extremity of the tube.

The raised central portion 46 and the cylindrical member 41, the diameter of which is substantially the same as that of the raised portion 48, form an annular passageway within the premixing chamber between the vertical wall thereof and the vertical wall of the raised portion 46 and the cylindrical member 67. The baiiies 48 carried by the cylindrical member 41 extend into the annular passageway thus formed.

Fuel oil is delivered adjacent the bottom wall of the premixing chamber through the fuel supply pipe 34 which communicates with a suitable opening in the vertical wall of the premixing chamber. A pair of vertically disposed partitions 52 of limited height are positioned on either side of the opening with which the fuel supply pipe 34 communicates. The partitions are disposed between the wall of the premixing chamber U and the raised central portion 46 whereby to form an open topped compartment 53 into which fuel oil is discharged by the fuel supply pipe 34. The upper extremity of the partitions 52 terminate beneath the lowermost baiile 45..

The mechanism contained within the control device 35 preferably regulates the flow of fuel to the premixing chamber whereby to prevent the oil rising within the compartment 53 above the partitions 52-. In this manner the oil delivered to the premixing chamber is confined within the open topped compartment 53 adjacent the outer wall of the premixing chamber whereby to limit the exposed surface area of the oil.

The air inlet openings 39 are formed in the external ribs 42 whereby the air admitted therebeing formed in the external ribs 45 whereby a gyratory motion is imparted ,to the air entering therethrough similar to the motion of the air Y entering through the air inlet openings 39.

When oil is delivered to the compartment 53 within theoil burning device shown in Figure chamber and air is admitted to the premixing chamber in a substantially horizontal direction toward the center of the chamber, the initial fire within the premixing chamber usually produces a large quantity of smoke and soot because some of the vapors are burned without the necessary combustion supporting air. In the present structure the bafiles 48 retard the escape of the oil vapors generated from the limited surface of the compartment 53 and the arrangement of the air inlet openings 39 cause the air entering therethrough to circulate to some extent around the premixing chamber between the baiiles 48 and over the compartment 53. The bafiles 48 likewise tend to prevent the immediate escape to the combustion chamber of the mixture of air and oil vapors formed in the premixing chamber whereby ample opportunity is afforded for an adequate supply of combustion supporting air to unite with the oil vapors. Accordingly, combustioninitially occurs within the premixing chamber without the formation of soot or smoke.

Once combustion has been initiated within the premixing chamber the resulting heat and air circulating over the compartment 53 cause a very rapid vaporization of the oil contained within that compartment. The surface area of the com-' partment'53 is so related to the size and number of air inlet openings 39 that the rate of va-' porization of oil from the compartment is substantially proportional to the volume and v'eloc-.

ity of the air passing over the compartment.

This proportion is such that the total quantity i of vapors which may be generated from the oil contained within the compartment 53 will be greater than the quantity necessary to form a completely combustible mixture with the air admitted through the air inlet openings 39 regardless of the draft conditions affecting the velocity of the air through the inlet openings. Combustion therefore occurs within the lower portion of the premixing chamber 2i for a short time. only and thereafter that portion of the chamber becomes filled with a mixture of air and oil vapors which will not burn without the addition of a further supply of combustion supporting air. As the premixture ascends spirally about the central tube toward the combustion chamber its velocity is reduced somewhat and it becomes a more nearlyv uniform mixture as it approaches the upper region of the premixing chamber where the combustion supporting air enters. The inclined air inlet openings 40 project the combustion supporting air into the swirling uniform premixture in substantially the same direction as that of the premixture but at a relatively greater velocity and with a more pronounced gyratory movement.

Because of the greater velocity of the combustion supporting air it circulates rapidly throughout the premixture and quickly forms a homogeneous completely combustible mixture of air and oil vapors which rotates about the.

'upper region of the premixing chamber and passes into the combustion chamber in a rapidly chamber and are distributed evenly throughout the same. It'should be observed that for the same reason the combustion chamber need not be as long as similar chambers utilized heretolore, where combustion occurs in a vertical zone rather than a horizontal zone.

Where combustion supportingair is supplied through spaced apart air inlet openings, as herein shown, there is a tendency for a'series of explosions to occur adjacent the inlet openings.

This is due to the fact that the streams of air entering through adjoining openings are separated and unite with the premixture present to form explosive mixtures alternately close to the openings and remote from the openings. This tendency, which produces an objectionable noise,

is avoided in the present device by causing the separate streams of air entering through adjoining air inlet openings 40 to unite with each other before contacting the premixture passing upwardly to the combustion chamber. Obviously, various other devices might be utilized to accomplish this, such as, for example, reducing the velocity of the air admitted through the openings 40.

In the present device a pair of horizontally spaced apart annular rings 54 and '55 are positioned, respectively, above and below the air inlet openings 40. The horizontal extent of the rings is sufficient to permit the inclinedstream of air entering through one inlet opening 40, to unite with the next adjoining stream before they pass'through the gap formed by the rings 54 and 55 into the upper region of the premixing chamber. In this manner the combustion supporting air is delivered uniformly to the premixture. The ring 55 is seated upon the shoulder 43 formed adjacent the upper extremity of the vertical wall of the chamber 2|. It is secured in position by reason of its complementary engagement with the shoulder 43 and the adjacent vertical portion of the chamber wall. Ring 54 is seated upon supports 55 and 51 carried by ring 55.

Due to fluctuations in the draft and the heat of combustion there is a tendency for down currents or eddies to be set up within the premixing chamber whereby the eflicient operation thereof is impaired. In the present device the upper wall 49 of the cylindrical member 41 and the baflies 48 carried thereby tend to prevent the premixture from eddying back into the premixing chamber after it has been discharged therefrom as just described;

,A small quantity of the premixture collects immediately above the wall 49, however, because the wall is spaced below the air inlet openings 40 and there is a small region within which down currents may be set up. The premixture'which collects in this region is normally only partially burned because there is not sufficient air present to support the complete combustion thereof. When this occurs a slight amount of smoke results and there is frequently a deposit of soot or carbon formed on the wall 49.

This objectionable formation of soot and smoke is prevented by providing a sufficient amount of combustion supporting air to unite with the premixture trapped above the wall 49. Air is supplied for this purpose through the tube 50 which communicates with the atmosphere beneath the premixing chamber 2!; The cap 5| deflects the air entering through the tube 50 whereby to direct it over the surface of the wall 49.

Whilethe oil burning device embodying the present invention-is designed especially for use with naturaldraft, it will be obvious that it is equally suited for use with forced draft. Where.

natural draft is used there is a continual fluctuation in the strength of the draft. This, of course, varies the amount of air admitted through the air inlet openings 31 and 40. Ordinarily any substantial variation in the draft would destroy the balance between the oil vapors formed in the premixing chamber and the total amount of air admitted thereto to such an extent that the efllciency of the device would be materially impaired and in some cases practically destroyed.

These undesirable results are obviated in the present construction by limiting the surface area of the oil and passing the premixing air over this limited surface whereby the rate of vaporization of the oil, within wide limits, is p'roportional to the volume and velocity of the air entering and wherein the ra e of vaporization of oil is proportional to the preferred embodiment of the invention has been shown and described, it should be understood that the invention is not limited thereto but is coextensive with the scope of the appended' claims.

I claim:-- 1. Combustion apparatus of the character described comprising a burner chamber having a bottom wall and an annular side wall, the side wall provided with a plurality of primary air inlet apertures in the lower portion thereof and a plurality of secondary air inlet apertures adjacent the top thereof, all of said apertures inclined horizontally to the radius of the burner to give the air admitted therethrough a circumferential direction, a pair of closely spaced air baflle rings located inside of the burner above and below the secondary air inlet apertures, a fuel receiving sump of limited circumferential and radial extent formed on the bottom wall adjacent the side wall, a wall of the burner being provided with a fuel inlet opening adapted to deliver fuel to said sump, and a horizontally disposed baflie arranged within the burner to partially overlie the top of said sump.

2. Combustion apparatus of the character described comprising a burner chamber having a bottom wall and an annular side wall, a fuel receiving pump of limited circumferential and radial extent formed on the bottom wall adjacent the side wall, a wall of the burner being provided with ow of air. While only the baiiie positionedto partially overlie the sump, said side wall being provided with a' plurality of primary air inlet apertures in the lower portion thereof, said apertures being inclined horizontally to the radius of the burner to give the air 'admitted therefrom a circumferential direction and cause the same to circulate over said fuel sump and between said baflles to form a premixture, said side wall also being provided with a plurality of secondary air inlet apertures adjacent the top thereof for admitting additional air to form a combustion mixture, said secondary air inlet apertures being inclined horizontally to the radius of the burner in the same direction as said primary air inlet apertures.

3. Combustion apparatus of the character described comprising a burner chamber having a bottom wall and an annular side wall, a fuel receiving sump of limited circumferential and radial extent formed on the bottom wall adjacent the side wall, a wall of the burner being provided with a fuel inlet opening adapted to deliver fuel to said sump, a horizontally disposed'baflle arranged in the center of the burner above said sump and positioned to partially overlie the sump, said side wall being provided with a plurality of primary air inlet apertures in the lower portion thereof, said apertures being inclined horizontally to the radius of the burner to give the air admitted there-'- from a circumferential direction and cause the same to circulate over said fuel sump adjacent said baille to form a premixture, said side wall also being provided with a plurality of secondary air inlet apertures adjacent the top thereof for admitting additional air to form a combustion mixture, said secondary air inlet apertures being inclined horizontally to the radius of the burner in the same direction as said primary air inlet apertures. 5

4. Combustion apparatus of the character described comprising a burner chamber having a bottom wall and an annular side wall, a fuel receiving sump of limited circumferential and radial extent formed von the bottom wall adjacent the side wall, a wall of the burner being provided with a fuel inlet opening adapted to deliver fuel to said sump, a horizontally disposed baille arranged in the center of the burner above said sump and positioned to partially overlie the sump, said baiiie being mounted on a central tube having a closed upper extremity provided with an air discharge opening located below the top of the burner, said side well being provided with a plurality of primary air inlet apertures in the lower portion thereof, said apertures being inclined horizontally to the radius of the burner to give the air admitted therefrom a circumferential direction and cause the same to circulate over said fuel sump adjacent said baiiles to form a premixture, said side wall also being provided with a plurality of secondary air inlet apertures adjacent the top thereof for admitting additional air to form a combustion mixture, said secondaryair inlet apertures being inclined horizontallyto the 80 radius of the burner in the same direction as said primary air inlet apertures.

BENVALJEAN.

CERTIFICATE OF CORRECTION.

Patent No. 2,068,441- r January 19, 193i BEN VALJEAN.

It is hereby certified that error appears in the printed specificationo the above numbered patent requiring correction as follows: Page 1, first column. line 6, for the word '"is" read may be; and line 9, for "may be read is; page 4 second column, line '69, claim 2, for "pump" read sump; one that the said Letters Patent shoulcibe read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 16th day of February, A. D. 1937.

Henry VanArsdale (Seal) Acting Commissioner of Patents.

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