US2198485A - Hydrocarbon burner - Google Patents

Description

April 23, 1940.

G. PIRICH HYDROCARBON BURNER Filed June 12, 1937 Sheets-Sheet 1 l/vwwroz GEORGE P/R/CH 1 7 03min;

April 23, 1940.

f G. PlRlcH HYDROCARBON BURNER Filed June 12, 1937 5 Sheets-Sheet 2 /oooooooo5 0000 00000 0000 0000 ooooocWoo fiwavroe 650w: PIE/CH April 23, 1940. e. PIRICH 2,198,485

' HYDROCARBON BURNER Filed June 12, "1937 s Sheets-Sheet.- s

Patented Apr. 23, 1940 UNITED STATES m];

HYDROOARBON BURNER George Pirich, Minneapolis, Minn.

Application June 12, 1937, Serial No. 147,877

6 Claims. (Cl. 158-53) My present invention relates to hydrocarbon like characters indicate like parts throughout the burners, more commonly designated as oil several views. burners and provides highly important contribu- Referring to the drawings: tions to this art. Fig. 1 is a view in side elevation of one of two Hydrocarbon burners may be broadly divided forms of my invention herein illustrated and 5 into two general classifications, to wit: (a) the described; socalled gun type burners, wherein low grades Fig. 2 is an enlarged detail view taken on the of hydrocarbon fuel such as fuel oil are mechaniline 2-2 of Fig. l; cally broken up into fine particles and sprayed Fig. 3 is an enlarged detail view sectioned on into the combustion chamber in a mist-like state the line 3-3 of Fig. 2, looking downwardly and 10 and burned in that condition, and without preturned 90 in a clockwise direction;

vious application of heat; and (b) the-so-called Fig. 4 is a sectional view taken on the line generating or vaporizing type of burner, wherein 4-4 of Fig. 3; the hydrocarbon fuel is heated to a point above Fig. 5 is a view in side elevation, with some its critical temperature by the process known as parts broken away and some parts shown in sec- 1:;

generation and is delivered to the combustion tion, of another form of burner made in accordchamber in a volatile or gasified condition and ance with the instant invention; burned as a gas. This invention relates to this Fig. 6 is an enlarged detail view taken on the latter type of burner, designated as (b) above. e 65'of F Burners of this generating or vaporizing type, Fig. '7 is a detail sectional view taken on the designated as (b) above, have long been regarded line of Fig. 6 and turned 90 in a clockwise as the most efficient type for use with low direction; grade hydrocarbon fuels, but, since hitherto pro- Fig. 8 is a sectional view taken on the line duced burners of this type have been diflicult to 8-8 of F g. 7; and

ignite, particularly when cold, this type of burn'er Fig. 9 is a sectional view taken on the line 25 has largely been displaced by the less eflicient 9--9 of Fig. '7. but, nevertheless, more easily ignited so-called With reference first to the form of the ingun type, designated as (a) above, since in this vention illustrated in Figs. 1 to 4, inclusive, the gun type, ignition is comparatively easy and can numeral 60 indicates a motor driven blower havreadily be accomplished by conventional autoing an ey inlet opening a Va q p o matic ignition systems, rotor 12, a rotor shaft I3, and a tangential dis- One very important object of the invention is h r b r el l4. The bl wer I0 is mounted on the provision of a highly efficient hydrocarbon a Suitable e of pp t o mounted on burner of the so-called generating or vaporizing which base of Suppo is a fluid pressure p p type, wherein low grade hydrocarbon fuel u h l6 that is driven from the motor driven blower 35 as fuel oil is prepared for combustion and can shaft I3 through driving connections comprising easily be ignited, even when the burner is in a belts and P y ll. T e fl d pr ure pump cold state, and wherein the hydrocarbon fuel will I m y be assumed to h ve its inlet connectedbe subject to the process of self-generation or to a bl Source, not shown, of hy roc rbon 40 vaporization after combustion is established, to fuel Such as fuel by a fuel conduit l8. The 0 thereby materially raise the efliciency of the outlet of the P p is Connected y a P p burner. l9 to a fuel discharge nozzle 20 located within Another equally important object of th inv nthe discharge end of the blower discharge barrel tion is the provision of an improved ignition sys- I4. The parts thus far described constitute the tern for hydrocarbon burners, which ignition sysm j elemonts of a so-oalled gun yp of burner. tem, while adapted for use in connection with in which fuel projected from the nozzle 20 under various difierent types of hydrocarbon burners, r l v y high Pressure r ated by the pump is particularly used in connection with hydro- I5 is mixed W the air Passing o h the discarbon burners of the generating or vaporizing charge barrel I4 of the blower and burned off the type and is herein illustrated in connection with end of the nozzle 20 in a mechanically broken- 50 my improved generating type burner. up cold state.

The above and numerous other important 010- In accordance with the forms of my invention jects and advantages of the invention will be herein chosen for the purpose of illustration, a made apparent from the specification, claims generating type burner head, indicated as an '5 and drawings. In the accompanying drawings entirety by M, is mounted on the open end of the discharge end of the barrel ll of the blower, so that air and oil emanatingfrom the discharge barrel l4 and nozzle 28 mix within and pass through this burner. This nozzle burner head, which in a generic sense forms a continuation of the discharge barrel I4 is preferably formed of cast iron and is provided at its intake end with a sleeve-like mounting flange 22 that is telescoped over the discharge end of the barrel l4 and detachably secured thereto by screws or the like I 23. Immediately outwardly of the coupling sleeve 22 the cast head 2| is formed to afford a primary fuel and air mixing chamber 24 that opens into branch generating or vaporizing ducts 25 that diverge outwardly from the primary mixing chamber 24 and discharge into a common combustion chamber 26. These tortuous branch generating ducts 25 preferably open somewhat tangentially to the vertical axis of the combustion chamber 26, so that the fuel and air mixture entering the combustion chamber 26 from opposite generating ducts or tubes 25 will set up more or less of a vortex within the combustion chamber 26; The combustion chamber 26, in this form of the invention, is in the form of an open topped pot that extends a greater distance below the branch generating ducts 25 than above the same and is provided in its walls below the generating ducts 25 with numerous flame discharge orifices 21. 4

At this point it may be well to state that liquid fuel injected into' the air stream in the mixing chamber 24 by the nozzle 28 mixes with the air and passes through the generating conduits or ducts 25 and is delivered into the fire pot in the nature of a cold mist, which may be ignited by suitable means, and burns in the fire-pot-like combustion chamber 26. This cold mixture of oil and air is readily ignitable in the combustion chamber, even in the absence of any pre-heating whatever, but when ignition occurs, a relatively large flame will issue from the open upper end of the combustion chamber 26; and smaller flames will issue from the numerous orifices 21 in the lower portion of the combustion chamber below the plane of the generating ducts' 25. These smaller flames will very rapidly heat up the entire burner-head structure, inclusive of the tortuous generating or vaporizing ducts 25; and when these areheated, combustion will be much more complete than when the structure is cold, and the efliciency of the burner will'be materially increased. In other words, when the walls of the tortuous passages become hot, the cold fuel particles will be heated beyond their critical temperature and will be vaporized and mixed with the air in a vaporized condition, thereby producing a more highly combustible mixture than is the original cold mixture. The lighter particles of oil issued from the nozzle 28 will, for the most part be carried by the air stream directly through the tortuous passages without being impinged upon or brought into surface contact with the walls of the ducts 25, but the heavier and harderto-burn particles, along with some of the smaller particles, will be impinged against the tortuous walls of the generating ducts 25, where they will immediately be vaporized and returned to the air stream as a vapor. Of course, when starting cold, those oil particles which are impinged upon the surfaces of the passages will tend to condense on those'surfaces, but, as previously stated, the surfaces are brought up to a high temperature very rapidly after combustion is established, so that any moisture collected on these surfaces during the initial warming up period will be completely vaporized and returned to the air stream and later burned.

Preferably the burner head will be sloped slightly toward the combustion chamber 26, so that such fuel as condenses upon the cold surfaces of the generating passages 25 during the initial warming up period will tend to flow toward and into the combustion chamber 26.

The burner described incorporates a novel ignition system immediately to be described. Above the primary mixing chamber 24 the burner head 2| is provided with a small auxiliary combustion chamber 28. The rear end of this small auxiliary combustion chamber 28 opens into the blower discharge barrel |4 through a port 29, see Figs. 2 and 4, and the front end of this small auxiliary combustion chamber 28 is connected by a fire flue 29' to the interior of the burner combustion chamber 26. Leading into the small auxiliary combustion chamber 28 from the primary mixing chamber 24 is a fuel mixture diverting passage 38. This passage 38 is afiorded by a relatively small tube 3| that has its lower rear end located to intercept part of the sprayed fuel and air mixture moving through the primary mixing chamber 24. Fuel and air mixture thus intercepted by the tube 3| is delivered diagonally into the small secondary combustion chamber 28 and mixed with the air stream which passes through the secondary combustion chamber 28 and fire flue 29 under pressure produced in the barrel by the blower.

For establishing primary ignition I provide a pair of spaced sparking electrodes 32, the ends of which terminate just short of the path of travel of sprayed fluid passing through the tube 3|. These electrodes 32, which are conventional in character, and may be assumed to be energized from a suitable high voltage source, may be supported in any desired manner, but, as illustrated, this is accomplished through the medium of insulating tubes 33 and brackets 34 from the oil delivery tube Hi. The sides and bottom of the secondary combustion chamber 28 and fire flue 29' are formed in the cast burner head, but the top wall of said flue and secondary combustion chamber are formed by a detachable cover 35, which, when removed, permits access to the electrodes 32 and tube 3|.

To start the burner the motor driven blower l8 and motor driven pump |6 are simultaneously set into motion, and simultaneously therewith the electrodes 32 are energized so as to produce a high tension are between the free ends of the electrodes. Under the action of the blower air will be moved through the various passages in communication with the blower barrel M at quite high velocity, and under the action of the pump |6 a relatively high fluid pressure will be built up in the oil delivery pipe IS, with the result that oil will be broken up into fine particles by the nozzle 28 and projected into the primary mixing chamber 24 in the nature of a fine spray which will, as previously pointed out, for the most part, be carried through the tortuous ducts 25 with the air with which it will be mixed and delivered to the combustion chamber 26 in the form of a cold but, nevertheless, combustible mixture. Part of the oil and air mixture moving in the primary mixing chamber 24 will be diverted to the auxiliary combustion chamber 28, where it will immediately be ignited by sparking between the electrodes 32; and as soon as the ignition takes place within the auxiliary or secondary 75 combustion chamber 28, the flame will be blown through the fire flue 29a into the main combustion chamber 26, where it will immediately ignite the cold fuel and air mixture issuing from the generating ducts 25. As a matter of fact, in operation ignition will be established in the auxiliary combustion chamber 28, and the resultant flame will be delivered to the main combustion chamber 26 almost simultaneously with the initial delivery to the combustion chamber 26 of combustible mixture through the generating passages 25.

The arcing ends of the electrodes 23 do not need to be extended into the fuel spray issuing from the upper end of the diverging tube 3! but may be terminated in rearwardly spaced relation thereto, since the air stream moving in the direction of the issuing mixture will blow the sparks or arcs into the mixture to ignite the same. This is, in fact, in accordance with conventional practice, in connection with the socalled gun type of burner. Of course, another function of the ignition system described is further pre-heating of the burner head.

This type of burner and the ignition system herein disclosed and described has been thoroughly tried out and has proved highly satisfactory. In practice it has been found that combustion is almost instantaneous when starting with a cold burner head, but that the characteristics of the flame improve very greatly under heating of the burner head during the first minute or two of operation. In practice, substantially, the entire burner head 2| will be projected into the fire box and boiler or furnace, and in Fig. 3 one wall of such a fire box wall is indicated by as.

The modified form of burner shown in Figs. to 9 inclusive will next be described. This modified type of burner is very similar to the burner described in connection with Figs. 1 to 4 inclusive and differs from the first described burner mainly in the fact that its main combustion chamber is horizontally disposed in place of being vertically disposed as in the first example. Due to the similarity between the structures, parts in the latter structure which arelike those in the first will not be described but will merely be designated by numerals corresponding to those assigned to like parts described in Figs. 1 to 4, plus the exponent a.

The horizontally disposed combustion chamber of the form of burner shown in Figs. 5 to 9 inclusive is indicated by the numeral 40 and is formed by a horizontally disposed cup 4|, the sides of which are illustrated as being imperforate. In this form of the invention pre-heating of the burner head is brought about through the use of an annular flame intercepting and directionreversing bafile 42, which is formed of suitable heat resisting material such, for example, as fire clay. This bafiie 42 surrounds the major portion of the combustion chamber 40 and has its front end turned inwardly about the free end of the fire chamber forming cup'40 but in spaced relation to the latter toprovide a reversely curved flame diverting passage 43. By reference particularly to Figs. 7 and 8 it will be seen that the baffle 42 is provided with an axial opening 44 that is concentrically disposed with respect to the combustion chamber 40 but is of somewhat less diameter than that of the combustion chamber 40.

In this form of the invention, as in the previously described form, the major portion of the burner head 2la can be extended'into the fire box and furnaceboiler or the like, but in this form the flame will issue in a horizontal direction from the combustion chamber 40 and part of this flame will be backwardly or rearwardly diverted about the intermediate portion of the burner head 2|, inclusive of the generating ducts or passages 25a thereon, by the annular baille 42. In Fig. 5 this latter type of burner is illustrated as being installed in the conventional type of boiler, indicated as an entirety by 45, and which boiler has at its base portion a fire box 46. The walls of the fire box 46 are preferably formed in the conventional manner by refractory substance such as fire brick 4I. The burner head 2la projects horizontally into this fire box 46 through the refractory walls 41 thereof, which latter serves to support the burner head. The deflecting bafile 42 may be supported in concentric but spaced relation to the combustion chamber forming cup 4| in any desired manner such, for example, as by a refractory wall 48 located in the intermediate portion of the fire box 46.

In Fig. 5 this wall 48 is illustrated as being one wall of an auxiliary fire box 49 that is approximately centrally disposed within the fire box 46 but has its walls spaced from the walls of the fire box 46 to afford flame passages 50 between the walls of the fire box 45 and the walls of the auxiliary fire box 49; The walls of the auxiliary fire box 49 are perforated to afford numerous flame passages 5|, but the top 52 thereof is preferably formed of an imperforate slab. The walls of the auxiliary combustion chamber may be assumed to be built up of fire brick, and the top 52 thereof may be assumed to be of similar baked fire-clay substance, but in any event, the walls and top of this auxiliary fire box should be of highly refractory material.

The operation of this latter form of burner will be very similar to the operation of the first described form of burner. That is to say, when the mechanism is initially set into operation, combustion will be first established in the auxiliary combustion chamber 28a and the flame thus produced will be blown into the combustion chamber 40 through the pilotv fire flue 29a, thereby establishing combustion of the cold fuel and air mixture projected into the combustion chamber 40 through the tortuous generating passages or ducts 25a. Part of the flame produced in and issuing from the combustion chamber 40 will be intercepted by the baffle 42 and discharged as an annular flame which will completely surround the intermediate portion of the burner head Zia. This rearwardly diverted annular flame will rapidly heat up the generating passages 25a, and when these are hot, the cold fuel mixture will be heated beyond its critical point andvaporized before delivery to the combustion chamber 40.

The major portion of the flame produced in the combustion chamber 40 will be discharged from the combustion chamber 40 through the axial opening 44 in the baffle 42 into the auxiliary fire box 49. After a short period of operation the walls and top of the auxiliary fire box 49 will become heated to a very high temperature, which will be a further assurance of complete combustion. The flame introduced into the auxiliary fire box 49 will issue from the numerous side wall openings 50 thereof, and the hot fumes will pass upwardly in close relation to the heat transfer walls 53 of the boiler 45. I

As previously indicated it is important in carrying out the invention that the nozzle 20 be of the type which breaks the fuel up into very small particles, and in this connection it may be stated that the invention has been successfully practised with the use of commercially obtainable nozzles used in connection with high pressure gun type burners such, for example, as are manufactured by the Bird Oil Company of Minneapolis, Minnesota, the Hubbard Oil Company of Minneapolis, Minnesota, the Sigwald En gineering Corporation of Minneapolis, Minnesota, and the Campbell Machine Company of Minneapolis, Minnesota, and numerous others.

Nozzles of this character are obtainable in various volumetric capacities ranging from a gallon and a half per hour under approximately one hundred pounds of pressure to three gallons an hour upwardly under approximately one hundred pounds of pressure. Another source of such nozzles is Nitroil Laboratories, St. Paul, Minnesota. Since the nozzles described deliver their rated fuel output at approximately one hundred pounds pressure, it may be assumed for the purposes of this case that the fuel pumps l6 and "a are capable of delivering fuel to their respective nozzles 20 or 20a under approximately one hundred pounds pressure.

What I claim is:

1. In a hydrocarbon burner adapted to burn non-volatile hydrocarbon fuels, a mixing chamber, a pair of generating tubes opening from the mixing chamber in diverging relation and arranged to discharge toward substantially the same point, means for maintaining forced circulation of air through said mixing chamber and generating tubes, means for introducing such a fine spray of non-volatile hydrocarbon fuel into the mixing chamber that it will mix with the air moving through the mixing chamber and generating vtubes to produce'a cold but highly inflammable mixture, the discharge ends of the generating tubes being so arranged with respect to the intermediate portions of the generating tubes that the heat of combustion of the mixture discharged from the generating tubes will heat the intermediate portions of the generating tubes.

2. The structure defined in claim 1 in which the said generating tubes discharge into a common combustion chamber, that is so arranged with respect to the intermediate portions of the generating tubes that flames will issue therefrom to heat the generating tubes.

3. The structure defined in claim 1 in which the said generating tubes discharge into a common vertically disposed combustion chamber having an open upper end above the discharge ends of the generating tubes and apertures below the generating tubes for omission of flames for heating the generating tubes.

4. The. structure defined in claim 1 in which the said generating tubes open into a common horizontally disposed combustion chamber that is located entirely beyond the generating tubes, and in further combination with means for intercepting flame issuing from the horizontally disposed combustion chamber and diverting the same backwardly about the generating tubes.

5. The structure defined in claim 1 in further combination with an automatic ignition system comprising an auxiliary mixing chamber laterally spaced from but closely associated with the aforesaid mixing chamber, a fire flue opening from the auxiliary mixing chamber and having its discharge end closely associated with the discharge ends of said generating tubes, the other end of said mixing chamber being subject to said forced air-circulation means, means for diverting a portion of sprayed fuel mixture moving in the first said mixing chamber and delivering the same to the said auxiliary mixing chamber, and

means for igniting the mixture in said auxiliary mixing chamber.

6. The structure defined in claim 1 in further combination with an automatic ignition system comprising an auxiliary mixing chamber laterally spaced from but closely associated with the aforesaid mixing chamber, a fire flue opening from th auxiliary mixing chamber and having its discharge end closely associated with the discharge ends of said generating tubes, the other end of said mixing chamber being subject to said-

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