US2796923A - Oil-burner and combustion head construction and installation - Google Patents

Description

June 25, 1957 E. R. FISKE ET AL 2,796,923

OIL-BURNER AND COMBUSTION HEAD CONSTRUCTION AND INSTALLATION Filed March 11, 1953 ADJUSTABLE INTAKE ,7

r- 2,796,923 Patented June ,5,

OIL-BURNER AND COMBUSTION HEAD CONSTRUCTION AND INSTALLATION Edward R. Fiske, Scarsdale, and Michael A. Crozier,

Mount Vernon, N. Y., assignors to National Fuel Conservation Co., Inc., White Plains, N. Y., a corporation of New York Application March 11, 1953, Serial No. 341,774

9 Claims. (Cl. 158-76) This invention relates to combustion and more particularly to achieving economical and improved efliciency in heat-transfer units fired by oil-burners of the oil-pressure-spray air-blower type, usually known as the gun type of oil burner.

One of the objects of this invention is to provide a heat-transfer unit of the above-mentioned type in which fuel economy and greater efiiciency can be achieved, particularly in known and existing household-types of heat exchange installations; also to provide a practical and dependable means for converting existing systems of this type to a mode of operation that will substantially improve its efiiciency thermodynamically, lower its cost of operation, and lower maintenance expense.

Another object is to provide an oil burner construction of improved efliciency, of inexpensive structure, and well and simply adapted to achieve thermodynamic action superior to and more economical and efiicient than heretofore known and used apparatus. Another object is to provide an inexpensive and reliable device or means by which existing installations may be readily and without great cost converted to achieve better economy, material savings, and improved and long-lasting thermodynamic interaction in effecting heat exchange, as for household heating purposes.

Another object is to provide an oil-burner of the above-mentioned type, with means for simply, effectively, and efficiently achieving optimum turbulence of air relative to the oil spray and coacting optimum air velocity, all in relation to the thermal characteristics of the furnace or heat-exchange device involved, particularly in relation to draft and flue or stack escape of combusted or exhaust gases. Another object is to carry out the last-mentioned object without materially sacrificing air velocity (in vaporized oil combustion) for air turbulence, or vice versa, as is characteristic of known constructions, known modes of operation, and installations heretofore known, which additionally sacrifice or jeopardize one or more of the factors of thermal efficiency, over-all economy, low maintenance, freedom of sooting up, low CO2 fiue gas content, avoidance of heat-exchange with excessive flow of air (which means B. t. u. loss up the stack), or completeness of combustion of vaporized oil (which means loss of fuel up the stack as well as uncleanliness and costliness of maintenance), and others.

Another object is to provide an inexpensive means, easily installed, for converting existing installations of the above-mentioned type into a system and apparatus for avoiding one or more or all of the above-mentioned handicaps or shortcomings or ineffectivenesses; more particularly, an object is to provide a so-called combustion head that is of simple, inexpensive construction and provided with means or constructed so that it can be speedily, inexpensively and reliably installed in existing oil-burner heat-exchange units and thus make it possible to convert the action and mode of operation of the lat- 2 1 ter into such as achieves one or more of the abovementioned thermodynamic and economic advantages.

Another object is to provide an oil-burner combustion head that can be readily adapted to and installed in the so-called blast tube of oil-burners of the above-mentioned type, even though dimensionally such blast tubes vary. Another object is to provide a combustion-head unit of improved and superior coaction with the air-blast and high-pressure oil-spray and that can be inexpensively and dependably substituted in existing oil-burner installations. Another object is to carry out this last-mentioned object in a manner to suit a single combustion head to blast tubes of different diameters or dimensions.

Other objects are in general to provide a more efficient and improved oil burner construction and heat-exchange unit of the above-mentioned air-blast pressure-sprayed oil type. Another object is to improve combustion heads for oil-burners of the above-mentioned air-blast pressure-spray oil type. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrange ments of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown an illustrative embodiment of our invention and in which similar reference characters refer to similar parts throughout,

Figure 1 is a front elevation of a combustion head unit per se, certain parts, such as the high pressure oil spray nozzle and igniting electrodes being diagrammatically indicated;

Figure 2 is a side elevation thereof as seen from the left in Figure l;

Figure 3 is a rear elevation thereof as seen from the rear in Figure l and from the left in Figure 2, the oil nozzle and igniting electrodes being again diagrammatically indicated to show their relation to other parts of the head; a

Figure 4 is a central vertical sectional view of the combustion head as seen along the line 44 of Figure 1;

Figure 5 is a largelydiagrammatic or schematic representation or side elevation, partly in section or broken away, of a heat-exchange installation utilizing an oilburner of the above-described type, modified however by our above-mentioned combustion head; and

Figures 6, 7 and 8 are respectively central vertical sectional views, along the axis of the air-blast tube of the oil-burner, showing illustrative structural features of our combustion head whereby it is adaptable to oil-burner blast tubes of different internal diameters.

As conducive to a clearer understanding of certain features of construction and coaction in our invention, reference may first be made to Figure 5 in which we have schematically or diagrammatically shown a heat-exchanger 10 such as a household furnace or heater, fired by an oil-burner which is generally indicated by the reference character 11 and whichis of the type above mentioned. The furnace 10, which may be of any suitable or usual construction, as for heating circulated air or water, or for producing steam, has a combustion chamber or fire box 12 from which, after heat exchange, gases of combustion are ledby a smoke pipe 13 for exhaust to a chimney or stack not shown) which may be provided with any suitable form of draft-check or damper. Projecting into the fire box 12 is the blast tube 15 of the oil burner 11 which has the usual motor-driven parts, such as blower 16 provided with an adjustable air-intake 17 and having its outlet connected to the blast tube 15, and an oil pump 18 the output side of which is connected to the nozzle tube 20 which extends into the blast tube and has an oil nozzle closely adjacent the discharge end of blast tube 15. In known constructions, the fire box end of blast tube is provided with a combustion head through the front end of which the oil jet or sprayemerges, surrounded by air escaping from the blast tube and usually given a uniform twisting effect by internal inclined fins about the exit provided by the combustion head; it is here that known constructions are deficient and suffer such short-comings as those above noted. More particularly, in such known constructions it-is impossible or impracticable to achieve optimum air turbulence with optimum air velocity, in re lation to the thermal, volumetric, mechanical, and other characteristics including those of the stack or chimney, of any particular installation. As a result, many of the factors that contribute to high thermal efficiency, efficient combustion, cleanliness, low maintenance labor or costs, and the like are very materially impaired. According to our invention we make it possible in a simple, practical and eflicient'manner to prevent or materially alleviate impairment of such factors and we are thus enabled to achieve substantial fuel and other economies and many other advantages, such as those earlier above mentioned. Accordingly we provide the oil-burner unit 11 with a combustion head, generally indicated by the reference character 22, which is initially built into or assembled to the blast tube or which, according to other features of our invention, is easily and quickly substituted in an existing oil-burner installation; it has structural and functional features which achieve new coactions and modify the action of the burner as well as the coactions of its various parts, and make it possible readily to provide optimum or efficient coactions with the heat-exchanger 10 and its stack. a

Our invention and its various features may be best understood when described in connection with a form or embodiment, illustratively shown in Figures 1-4, of combustion head that is constructed also to permit ready assembly to existing burner installations as is illustratively shown in Figures 6-8. As indicated above, blast tubes are usually of circular cross-section and they vary widely in diameter; our combustion head, constructed to be assembled to the blast tube, is of corresponding general shape and in Figures 1-4 is shown as of circular cross section, having a cylindrical side wall 23 and an annular end wall 24 provided with a coaxial circular air-discharge opening 25 of suitable or usual area in relation to the diameter of the blast-tube and associated size of oil nozzle. The oil nozzle, diagrammatically indicated at 26, is carried at the endof the oil pipe which is coaxial with the blast tube 15 and when ourcombustion head is assembled to the latter, the air-discharge opening is coaxial or concentric with these parts, the axial position of the combustion head 22 relative to the blast tube 15 being such as to bring the orificed end face of the nozzle at a position (see Figure 6) spaced inwardly from the plane of the front face of the head and in desired relation to velocity-and-turbulence control elements, later described, which are provided internally of the head. In installations of I more usual type and size, this nozzle spacing may be on the order of 1/2 inches. 1

Conveniently the sleeve-like side wall 23 (Figure 4) is dimensioned to be telescopically received or fitted into the endofthe. blast tube 15 (see Figure 6) and in such case, inan initial assembly or factory construction, the combustion head may be secured in position by any desired means; where the head is to be a replacement in an existing oil burner installation, a telescopic interfitting is not always possible because of differing internal diameters g of blast tubes of .thefvarious existing styles and sizes of oil-burners and in such case we makeprovision, later described in detail, for easy assembly of a given size of our combustionheadcoaxiallyof or concentrically with blast tubes of a substantial range or gradation of diameters. In any-case, however, his preferred to orient the head of ouricons'truction 'rotatively. 'orabout the axis of the blast in order to achieve certain desirable coactions with the walls of the fire box 12 (Figure 5). The latter has a bottom 12 and it is more particularly in relation to the fire box bottom that we prefer'to effect orientation of the head. Accordingly, the head is provided, near the top of the face of end wall 24 (see Figure 1) with suitable indicia, such as the word top, so that, in assembling the head 22 to any blast tube, that indicia will be brought to the upper end of the vertical diameter of the blast tube of the oil-burner, whether the latter is still on a factory assembly floor or in an existing furnace or other installation. i

In so orienting our combustion head, we achieve orientation of a set of differently dimensioned vanes or blades on the inside of the head which we designate, for convenience, as a whole by the general reference character V; these angled vanes or blades are of unique interrelatiouship to each other and to above-mentionedvertical diameter. In relative disposition or arrangement, they are so arranged as to effect a different action upon the oil jet of the air emitted from the blast tube 15 and also different reactions or coactions of oil particles and air With the walls, particularly the bottom, of the fire box 12. These blades are shown in elevation in Figure 3, where they are seen as they face and are encountered by the column of air moving toward the right in the blast tube 15 in Figures 4, 6-8, and 5 under the actuating force of the blower 16 and they are shown, also in elevation, in Figure l as seen from the exit side of the air-discharge opening 25. lllustratively, they are six in number, a suitable number where the outside diameter of the head 22 is on the order of four inches; as will be better appreciated from the disclosure herein, they may be less or greater in numher, being usually greater in number with increase in diameter of the combustion head, so long as their relative shapes and dimensions and relative distribution about the axis of the combustion tube, follow the principles of our invention and thereby substantially alter the actions and modify coactions which contribute toward obtaining improved results and advantages such as those herein described.

As above noted, the vanes of set V in the illustrative embodiment shown are six in number; for further convenience they are given the reference characters 31, 32, 33, 34, 35 and 36, identifying them in olock wise order, in Figure 3, starting at the 9 oclock position. They are slanted but more or less grouped to give different effects above and below the central horizontal plane which is indicated by the line AA; they may be curved, though as suggested in the drawings, they may be substantially plane-faced so long as their slant is in appropriate dimotions to give relatively different velocity effects and swirling or rotative turning movements to the respective air stream portions above and below the plane A-A as they emerge, toward theright in Figures 4, 5, 6, 7, and 8, from the blast tube. In so far as turning or swirling effects are concerned, the vanes may be considered to be sections or portions of a helix, of substantial pitch, of fiat curvable ribbon-like stock; however, the sections or blades 7 31, 32, 33 of the group above the horizontal plane AA are smaller, being of lesser width, that is, in radial direction as seen in Figures 3 and 1, than are the vanes 34, 35, 36 of the group below the plane AA. Illustratively, the vanes of the upper group .3132-33 may terminate without substantially invading the projected area of the air-discharge opening 25 (see Figure 1) while the vanes of the lower group 3435-36 project, inwardly or in somewhat radial direction toward the axis or center, substantially and materially into the projected area of the outlet opening 25. This difference is illustrated in both Figure 3 and Figure 1. By such arrangement, we provide, in effect, an upper air-emission zone (above the plane AA as better appears in Figure 1) and a lower air-emission zone (below this plane A A) in the discharge opening 25 which conveniently and preferably are each semi-circular in efiective area and which, while complemental to each other to form prefereably the single round air-discharge opening 25, have materially different effects, as later described, upon the air they respectively discharge, yet in such manner as to coact with each other and other parts and with the coaxially or centrally ejected oil jet to greatly affect the functioning and improve the combustion action and efficiency of the oil burner.

In axial extent or dimension, these vanes or blades may be appropriately proportioned in relation to the internal diameter of the combustion head 22; illustrative'ly, substantially as shown or suggested in Figure 4. They may be of the same axial length and in such case, their back edges as the head is viewed in Figure 1, being the lefthand edges in Figure 4, can fall in or coincide with a plane transverse to the axis of the head, preferably in such a plane spaced inwardly somewhat from the air-entry end of the head; this arrangement leaves an unobstructed portion of the wall 23 for purposes later described. The inside face 23 of the cylindrical side wall 23 merges, by appropriate taper or convergence and suitable curvature as at 28 (Figure 4), into the inside face 24 of the annular front wall 24 about the air-discharge opening 25. The combustion head structure as thus far described may be unitary or integral throughout, being advantageously a single casting of, for example, cast iron, the various vanes projecting inwardly from the just-described inside faces 23 28 and 24 of walls 23 and 24 and being unitary with the walls into the curved angularity of which they lie.

Such of the vanes as project toward the axis of the head 22 and invade the projected area of the discharge opening 25, such as vanes 34, 35, 36 of the lower group (Figures 1 and 3), preferably fall short of reaching the axis and do so by a radial distance that is in excess of the radius of the oil pipe 20 and its nozzle 26, thus to provide suitable clearance, as indicated, when the head 22 is assembled to the blast tube 15 with which the oil pipe .and nozzle are coaxial. These vanes or substantial portions thereof are directly in the lower semi-circular airemission zone (below plane AA in Figure .1) of dis-: charge opening 25 and directly in the path of flow of air in that zone, being moreover distributed throughout the 180 degree extent of that zone and about the axis of the combustion head and along which axis (see Figure 6) the jet of oil is emitted under pressure from the oil nozzle 26; accordingly, the air emitted from this lower emission zone is swirled forcefully about that axis and hence directed also in many angularities toward and into the coil jet, being also guided toward and into the latter by the internal wall curvature 28 (see Figure 4) as the air moves, under the pressure of blower 16, toward the lesser-diametered periphery of discharge opening 25. This lower portion of the discharged air is thus subjected to substantial and variegated turbulence.

While this is happening, air discharges from'the substantially unobstructed upper semi-circular emission zone (above plane AA in Figures 1 and 3) of discharge opening 25; it emerges at substantially greater velocity than does its albove-described companion portion discharged through the vane-controlled lower emission zone, for it does not encounter the resistance to flow such as the vanes -34, 35, 36 of the lower group interpose in the lower emission zone, and while given some twist or swirl by the smaller internal vanes 31, 32, 33 of the upper group, the effect is to create some turbulence without, however, materially impairing emission velocity from the upper emission zone. This upper portion of the discharged air thus tends to reach out in generally horizontal direction toward the back wall of the tire box (see Figure in a sense, it may be said that it seeks to form a sort of kinetic ceiling or blanket spaced upwardly from the fire ibox bottom 12 and between this blanket and bottom, the lower emission zone discharges the above described an. Substantially along the axis of this total air discharge, in the direction of the axis of blast tube 15, is the jet or discharge of oil from oil nozzle 26 which, we find, is rapidly and eflFectively broken up into fine particles by the interaction of the highly turbulent lower portion of the air discharge with the higher velocity less turbulent upper portion and by the resultant action thereof upon the emitted oil, all accompanied by superior combustion achievable, as later described, in relation to whatever happens to be the characteristics of the heat exchanger and its smoke-pipe and stack. We find, among other advantages and useful results, that ;we can achieve superior fuel combustion, at full capacity, with material-1y reduced air-intake volume at the blower intake 17 (Figure 5 .when we replace known types of combustion heads in existing furnace installations by combustion heads of our construction. Apparently the distinctive upper and lower air streams above mentioned, :by their interaction upon each other, not only create a uniquely effective and efiicient turbulation to achieve distributed and complete breaking up and atomization of the fuel oil but also, by the apparent blanket-like action of the velocity of the upper air stream, achieve a retarding action in the fire box space to insure eflicient atomizing turbulation by the action of the turbulent lower air stream against, as it were, the stronger and more directional or more positive upper air stream; with such efiicient and complete oil atomizing, combustion of the fuel is vastly facilitated, air for its combustion being supplied from and by both of these portions of the air discharge and, because of the relatively higher velocity of the air discharged from the upper emission zone as compared to that emitted from the lower emission zone of discharge opening 25, the former supplies a greater volume than the latter and does so at just about that region, which may be principally above the plane AA, where maximum combustion can be had of the turbulated burn- ,ing mix of air and fuel particles initiated principally from the general regions both within the lower turbulated air how and the region of mechanical or physical interaction between both upper and lower air flow.

The oil delivered from nozzle 26 is emitted substantially coaxially from the blast tube in a diverging or somewhat cone-shaped spray; nozzles are constructed and available in difierent sizes according to the desired .rate of oil emission and also in selectable cone-angles of spray. With our combustion head, the high-velocity air stream or flow emitted from the upper emission zone tends to move more or less horizontally, more or less paralleling the axis of the cone-spray of oil which it intersects principally above the plane AA and impacts throughout about the upper deg-rec spread of the oil spray. Underneath plane AA, the slower moving stream or flow of air, which is discharged from the lower emission zone of the combustion head, can diverge (throughout about 180 degrees) and also has substantial twisting or turbulating motion because of the action thereon of the lower group of blades 34, 35, 36 and, somewhat concentrically and divergingly intersecting the cone-shaped spray (mostly below the plane AA), has a turbulating and breakingup effect on the oil of that part of the spray which it overtakes or encounters and in effect, because of its rotational or spiralling tendency, probably also carries or moves oil particles or droplets, including those already broken up by it, into the path of the high-velocity upper air flow to be further impacted. Thus a successive comminuting or atomizing action appears to take place. These impacting actions of therelatively high-velocity upper air stream take place at relatively high velocity and dependable atomizing of the oil results, breaking it up into minute particles that greatly facilitate combustion.

Whatever the actions that take place, we find, in replacing existing combustion he-ads by ours, that air-intake can be materially reduced, as by re-adjusting the blower air-intake aperture or apertures 17 ('Figure 5) and in many instances we are enabled also to replace the nozzle 26by one providing a lesser rate of oil emission. And in relation to the characteristics of the heat-exchange insta'h lation,including those of the stack, we find we are enabled to achieve also the advantages of appropriate stack draft; for example, in obtaining superior combustion with less or materially reduced air-intake,the volume of air and of gases of combustion are not in such excess (as is not infrequent in existing installations) that the stack cannot handle it. The resultant system as thus modified by our combustion head facilitates greatly the achievement of high CO2 content in the flue or stack gases and minimum or no smoke; for example, in numerous so modified installations, by actual test and measurement, CO2 content on the order of 11 or 12 percent with improved and minimum smoke readings has been achieved. Detrimental sooting up of the surfaces of the heat-exchanger 12 is avoided and efiiciency is improved.

To facilitate conversion of existing installations, in which as above noted the dimensions of the blast tube vary, we prefer to construct our combustion head so that a given size of construction thereof is readily assembled to any one of several differently dimensioned blast tubes, such as, by way of illustration, the three blast tubes 15, and 15 of Figures 6, 7 and 8 respectively which are of difierent and increasing internal diameters in the just-named order. Accordingly we make the combustion head 22 with sleeve-like side walls 23 of an outside diameter just about the same as the internal diameter of the smallest blast tube, being the blast tube 15 of Figure 6, so that the head 22 is neatly received within the blast tube with appropriate small clearance to compensate for manufacturing tolerances in the two dimensions, and provide the head 22 with removable external adapter rings of different thicknesses, one for each additional different size of blast tube within the desired range, as indicated in Figures 2 and 4 by the rings R and R The rings are preferably split as shown at S in Figures 1 and 3 to facilitate manufacture and to give each a ready yielda-bility or springiness for ease of assembly, shifting, or removal relative to the head. Preferably they are made of wire, of any suitable metal such as steel, and they may be of round cross-section; they are all of an internal diameter just about equal to the external diameter of the head 22 and, being split and by their conformation having some springiness as above noted, they are easily sprung or slipped onto the head 22 which they circumferentially embrace and snugly grip to hold them assembled, as during packing, shipping, handling, and the like, and to maintain concentricity with the head. The thickness of ring R adds to the external radius of head 22 an amount so that the effective overall radius of the head just about equals or is slightly less than the internal radius of the blast tube 15* (see Figure 7) which is over-size in relation to the head 22 per se (compare Figures 6 and 7). In like manner additional rings, such as ring R (see Figure 8), give the head an effective outside diameter for easy fitting into the next larger-internally-diametered blast tube, such as tube 1'5 which is over-size in relation to blast tube 15 of Figure 7.

Another advantage in making the rings of wire is that any desired number of rings of dilferent thickness are easily accommodated on a short portion of the substantial length of the external cylindrical surface of the combustion head (two, for example, as in Figures 1-4). Also whatever ring is selected for ultimate retention for installation (the rest may be discarded), it may be selectably positioned, along a suitable range of the length of head and spaced from that end of the head that is innermost (Figures 6, 7, 8) of the blast tube, in as much as it may be necessary at times to have the head 22-project more or less from the blast tube in order to appropriately space the front wall 24 with its discharge opening 25 axially in relation to the oil nozzle 26; in Figure 5 the head 22 is shown projecting from the blast tube 15 and in Figures 6, 7 and 8 lesser degrees of projection are suggested. Substantial forward projection usually occurs where the forward end of an existing blast tube has to be cut-off to remove whatever combustionheadisre lated to it; usually these heads are detachably mounted. Whatever the projection of head 22 for the blast tube, and there maybe cases where the head is spaced somewhat inwardly from the end of theblast tube, the selected and retained ring is positioned relatively close to the forward end of the mutual overlap between head and tube.' The ring R of Figure 7 or R of Figure 8, more or less interfits peripherally with both head and tube, an action aided by the springiness of the ring which accommodates it readily in compensation for possible minor surface irregularities on the head and tube, and when positioned as described, the ring can and does provide centering support for the head closely adjacent its outer (right-hand, in Figures 7 and 8) end and in that way may be brought into coaction with suitable assembly and support means provided peripherally at its inner end.

The latter preferably comprise three equi-angularly spaced radially adjustable elements conveniently in the form of screws 38 (Figures 2 and 1) threaded, prefer ably with a tight fit, into radially extending threaded holes preferably located in the inner end portion of the sleevelike head wall 23 (Figure 4) where it is unobstructed by the vanes or blades 31, 32, 33, 34, 35, 36. Screws 38 may be headed as shown and preferably their headed ends are on the inside of the combustion head. Their outer ends may thus be equally set in radial direction to fall in a circle, concentric with head 22, of a diameter about equal to the internal diameter of whatever blast tube into which the combustion head 22 has to be fitted.

For example, where no adapter ring is needed as in Figure 6, the rings R R etc. (Figures 1 to 4) are re moved from head 22, and the screws are set to project, usually slightly, from the head by an amount to take up any play or tolerance between the head and the blast tube within which the head is to be slideably received from the front end of the tube, so that the inner end of head 22 is fitted into tube 15 with a tight friction fit approximating a press fit, dependably holding it assembled, concentrically, to the blast tube and in effect also locking the screws 38. In the process of assembly, head 22 is prope'rly oriented in rotational direction by reference to the indicia top on its front face (Figure l) and also lengthwise of the blast tube end, as above described. The head 22 (Figure 6) is thus dependably assembled in proper coaxial relation to the blast tube, being supported within the blast tube at numerous peripherally distributed and axially spaced points or regions. If desired, a bit of suitable sealing content is smeared onto the outer cylindrical surface of the head as it is entered into the tube end, particularly where there'may be some substantial degree of tolerance or irregularity in surface-to-surface relation between the two parts. In either case, Wobble or other shift of the head cannot take place.

Where a compensating ring has to be employed such as ring R of Figure 7 or ring R of Figure 8, the selected ring is retained on the head 22 and screws 38 are radially adjusted to bring their outer ends into a concentric circle of a diameter like the outside diameter of the selected ring and which, in relation to the substantially corresponding internal diameter of blast tube (15 in Figure 7 and 15 in Figure 8), causes the screws, as indicated in Figures 7 and 8, to tightly interengage with the internal tube wall and provide a fit and also a virtual locking of the screws as above described in relation to Figure 6.

The screws are adjacent the inner and entering end of head 22 and as the latter is moved inwardly of the blast tube, the screws 38 maintain appropriate concentricity or co-axiality between the two so that, with the ring kept at the outer end of the head, sealing cement as indicated at C (Figures 7 and 8) is peripherally applied into the annular space between head and tube; when the head reaches the desired axial position, the ring is positioned close to the outer or right-hand end of the head and entered in between head and tube, facilitated by the yieldability or springiness of the split ring, thus providing centering support at that portion of the head 22 that is axrally spaced or remote from the centering support provided by the "screws 38, and if desired and preferably, cement is also applied peripherally as a follow-up to the mug.

The axially spaced centering supports respectively provided by the screws 38 at the inner end of head 22 'and the ring (R or R of Figures 7 and 8) at the outer end make for dependable coaxiality of relationships not only during operation of the modified oil-burner but also for purposes of assuring setting of the sealing cement without disturbing or distorting effects thereon. The cement C, when set, not only seals the mechanical junction between head and tube against by-passing or leakage of air but it can also co-act in maintaining fixedly the desired and intended oriented position or location of the substituted head 22.

It is thus possible, by manufacturing only several different diameters of heads 22, each equipped with adjust able screws 38 at one end and with a set of rings of different thicknesses at the other end, to meet field requirements, for installing any head, of a wide range of different blast tube diameters met with in existing installations. Over-all manufacturing and other costs, such as stock or inventory to be carried, can thus be reduced.

As above described relative to Figures 3 and l, the different characteristics but coacting effects of the two streams or flows of air emitted from the upper and lower emission zones respectively may be achieved by providing helical blade or vane sections that are directly effective in the lower half portion of the discharge orifice or opening 25, like vanes 34, 35, 36 as seen in Figure l, with none or practically no vanes directly effective in the upper half portion thereof (see above line A--A of Figure 1); however, as noted above, We prefer that some twisting effect be brought to bear upon the high-velocity air stream and therefore prefer to provide a group of vanes 31, 32, 33 therefore as above described, proportioned relative to the vanes 34, 35, 36 of the other group in the general manner earlier described. These may be accommodated interiorly or in back of the front wall 24 where they coact with the inside wall faces 23 28, 24 (Figure 4) and thereby also ample clearance space is provided for the insulated or other conductors, indicated at-40in Figures 1 and 3, that lead to or are part of the spark producing ignition devices related to the nozzle 26. The vanes of the high-velocity portion of the discharge opening 25 (the "group above plane A-A) may have less pitch or smaller angles of slant to the blast tube axis than those of the low-velocity 'turbulating portion of the opening 25 (below plane A-A) as is also indicated in Figure 3 and such feature as well as their lesser surface areas may be utilized to materially lessen the impedance to discharge of air from the upper emission zone in contrast to the lower velocity and very substantial turbulating effect caused by the differently acting vanes of the lower emission zone.

Moreover, the two groups may be formed by progressively increasing the general radial dimensions of the vanes, illustrated in clockwise direction in Figure 1, from a minimum dimension for vane 31 at about the 9 oclock position to a maximum dimension for vane 36, thus placing their inner edges along a curve somewhat like a spiral as appears better in Figure 3. The drawings show substantially the relative proportioning and positioning of the parts of a combustion head of an external diameter of 3% inches, and in this respect the drawings are intended to be illustrative; for example, the number of vanes shown may be varied and for materially greater diameters it is preferred to increase them in number substantially correspondingly.

It will thus be seen that there has been provided in this invention a system of combustion for oil-burner installations of the oil-pressure-spray air-blower type and a c- 1 0 acting combustion head therefore in which the several objects above noted together with many thoroughly practical advantages are successfully achieved.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment set forth, it is to be understood'that all matter herein'before set forth or shown in the accompanyihg drawing is to be interpreted as illustrative and not in a limiting sense.

We claim:

1. In a construction of the character described, in combination, an oil burner having an air-blast tnbe for entry through a wall of a fire-box with an internal oil tube and a spray nozzle at that end thereof adjacent the discharge end of the blast tube, a combustion head comprising a substantially annular member having an air discharge opening and having distributed about and spaced from the axis of the discharge opening thereof a plurality of vanes divided into two groups each of about l degrees extent and each to one side of a substantially diametric plane through the discharge opening of said memher, the vanes of one group having dimensional and pitch characteristics that provide substantial resistance to air flow and substantial turbulating effect thereon and the vanes of the other group having dimensional and pitch characteristics that provide relatively low resistance to air flow for high velocity discharge of air and relatively low turbulating effect thereon, mounting and securing means for said annular member coacting with the walls of the blast tube at the discharge end thereof adapted for substantially coaxially holding said member assembled to the blast tube in rotational and axial orientation of its two groups of varies in relation to said nozzle so that, when the blast 'tube is related to the firebox, said diameric plane through said annular member is substantially parallel to the fire-box bottom with the first-mentioned group of blades on that side of said diametric plane nearest the fire-box bottom, and means for adjusting the air supply to said blast tube.

2. A combustion head for attachment to the discharge end of an oil burner blast tube that has an internal =oil tube and an oil spray nozzle at the end of the latter, said combustion head comprising a substantially annular member having an air discharge opening adjacent to which said annular member has internally distributed about and projecting toward but with their ends spaced from the axis of the discharge opening thereof a plurality 'of vanes divided into two groups each of about degrees extent and each to one side of a substantially diametric plane through the discharge opening of said member, the vanes of one group having dimensional and pitch characteristics that provide substantial resistance to air flow and substantial turbulating effect thereon and the vanes of the other group having dimensional and pitch characteristics that provide relatively low resistance to'air flow for high velocity discharge of air and relatively low turbulating effect thereon, and means for mounting and securing said vaned annular member adapted to coact with the walls at the discharge end of the blast tube for substantially coaxially holding said member assembled to the blast tube in rotational and axial orientation of its two groups of vanes in relation to said nozzle.

3. A combustion head as claimed in claim 2 in which said annular member has a cylindrical wall and said mounting and securing mean-s comprises a plurality of means respectively operative at axially spaced regions of said cylindrical wall, one of said last-mentioned means comprising a plurality of radially adjustable circumferentially spaced elements adapted to coact between said cylindrical wall and the wall of the blast tube for centering one relative to the other and the other of said lastmentioned means comprising a removable ring circumferentially effective about said cylindrical wall and adapted for interpositioning between said two walls where the diameters of the latter are of materially different lengths and adapted for removal where the said diameters are substantially the same and said walls are substantially telescopically receivable one within the other.

4. In a construction of the character described, in combination, an oil burner having an air blast tube for entry through a wall of a firebox with an internal oil tube and spray nozzle at that end thereof adjacent the discharge end of the blast tube for effecting a substantial cone-like divergent oil spray, a substantially annular combustion head at the discharge end of the blast tube for coaction with the substantially cone-like divergent oil spray emitted from said nozzle, said combustion head having means therein for effectively dividing air admitted thereto from said air blast tube into two streams at different sides of the axis of said cone-like divergent oil spray, one stream of relatively high velocity and low turbulence and the other stream of low velocity and high turbulence, said means including an array of internal projecting pitched vanes arranged in an are on one side of said axis to create the stream of low velocity and high turbulence, and means coaxially securing said combustion head against movement relative to said blast tube and in rotationally oriented position relative to said axis so that, when said blast tube is related to said firebox, said vanes are on that side of said axis nearest the bottom of the firebox.

5. A combustion head for attachment to the discharge end of an oil burner blast tube that has an internal oil tube and oil spray nozzle at the end of the latter for effecting a substantial cone-like divergent oil spray, said combustion head being substantially annular for directing air from the blast tube into coaction with the substantially cone-like divergent oil spray emited by the nozzle, said annular combustion head having means therein for effectively dividing air admitted thereto from said blast tube into two streams at different sides of the axis of said cone-like divergent oil spray, one stream of relatively high velocity and low turbulence and the other stream of low velocity and high turbulence, said means including an array of internal projecting pitched vanes arranged in an are on one side of said axis to create the stream of low velocity and high turbulence, and means for attaching said head to the discharge end of a blast tubeand adapted to relate the axis of air emission with the axis of the oil nozzle whereby to subject a portion of the divergent oil spray from the nozzle to the air stream of high velocity and low turbulence and another portion of the oil spray to the air stream of low velocity and high turbulence.

6. A combustion head as claimed in claim 5 in which said means for effectively dividing the air from said blast tube include a second array of internal projecting pitched vanes, said second array being arranged in an are on the other side of said axis, the pitch of said last mentioned vanes being less than the pitch of the first mentioned vanes, whereby the vanes of said second array have less turbulating effect upon the air than the vanes of said first array. v

7. A combustion head as claimed in claim 5 in which said means for effectively dividing the air from said blast tube include a second array ofinternal projecting pitched vanes arranged in an are on the other side of said axis, the eifective dimensions of the vanes of said second array being less than those of the vanes of said first array, whereby to provide less turbulating effect upon the air than the vanes of said first array( 8. A combustion head as claimed in claim 5 in which said means for efiYectively dividing the air from the blast tube include a second array of internal projecting vanes on an are substantially complementary to said first men tioned arc and of which a substantial number are of materially shorter radial length than said first mentioned vanes whereby the shorter vanes oifer low resistance to the flow of air from said blast tube.

9. A combustion head as claimed in claim 5 in which said means for effectively dividing air emitted from said blast tube include a second array of internal projecting vanes on an are substantially complementary to said first mentioned are, all of the vanes being arranged in a substantially continuous series about the internal periphery of said annular combustion head, successive vanes in the series being of progressively greater radial dimension, the vanes of the lesser dimensioned portion of the series lying on one side of said axis to permit high velocity and low turbulation air flow and those of the greater dimensioned portion of the series lying on the other side of said axis.

References Cited in the file of this patent UNITED STATES PATENTS

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