US2215079A

US2215079A - Apparatus for burning gas

Info

Publication number: US2215079A
Application number: US88744A
Authority: US
Inventors: Frederic O Hess
Original assignee: SELAS Co
Current assignee: SELAS Co
Priority date: 1936-07-03
Filing date: 1936-07-03
Publication date: 1940-09-17
Anticipated expiration: 1957-09-17

Description

t F. OA HESS APPARATUSFOR BURNING GAS Filed July 5, 1936 3 Sheets-Sheet l v BY g.

ATTORNEY 3 Sheets-Sheet 2 Sept; 17, 1940. F. o. HEss APPARATUS FOR BURNINGy GAS Filed July s, 193s' ifa Sept. 17, 1940. y F. o'. HESS APPARATUS FOR BURNING GAS Filed July 3, 1936 3 Sheets-Sheet 3 ATTORNEY lNvENToR F/PffR/c O, H556 .Patented Sept. 17, 1940 APPARATUS Fon BURNING GAS Frederic 0. Hess, Philadelphia, Pa., assignor to rlrhe Selas Company, Philadelphia, Pa., a corporation of Pennsylvania Application July 3, 1936, Serial No. 88,744

23 Claims.

tively highvcombustion and furnace temperatures, v

w transmission by radiation of a relatively large portion Aof the heat generated, and the maintenance of a definitely oxidizing or reducing, or a neutral combustion space atmosphere. The invention may also be used with advantage, howib ever, in connection with kitchen ranges, and for other purposes where the above mentioned operating conditions or characteristics are undesirable or not essential.

My improved method of combustion is char- 20 ,acterized primarily by the passage of/the combustible gaseous mixture' into a combustion space, wholly or partially surrounded by a refractory wall, in a multiplicity of jets igniting'and burning in said space, and thereby forming a multi- 2c plicity of separate flames or burning Jets extending alongside said refractory wall, which is shaped and disposed to avoid impingement thereagainst of the inner flame cone portions of the flame Jets, while permitting the wall portion immediately :m adjacent each flame jet to be heatedto incandescence.

For the practice of my improved method of combustion, I have devised apparatus which in its preferred forms, comprise both circular burner 35 units and elongated burner units. In the preferred form of my circular type burner unit, the

flames, or burning combustible mixture Jets, are

arranged ina circular row coaxial with the combustion space which is circular incross section 40 and increases in diameter with, though not in exact linear proportion with, the distance from the end of the space at which the combustible mixture jets enter said space, and the different jets similarly diverge from the axis of the com- 45 bustion space. While the angle of divergence from the` axis of the combustion space at which the fuel mixture jets enters said space may vary through quite wide limits, it is essential in general that that angle should be such that the angle at 50 which the tip portions of the flames of full burner capacity length diverge from the burner axis. should be appreciably less than 90, so that the combustion space, which must be 'formed in correspondence with the flame shapes, will be cup 5s shaped. In such case, the angle of divergence of the flame from the burner. axis diminishes along the length of the flame from the point at which the Jet is introduced into -the combustion space, so that the different flames are concave to the burner axis, generally, as the ribs of an ordinary umbrella, when in its open condition are concave to the umbrella axis as a result of the tension of the umbrella fabric.

The describedl concavity of the flames to the burner axis is due, as I believe, to what may be termed the aspirating action of the flames, which makes the gaseous pressure within the zone or space surrounded by the flames somewhat less than the gaseous pressure at the outer sides of the flames, so that the latter are bent inwardly by the excess of the pressure on their outer sides over the opposing pressure on their inner sides. Whatever the explanation may be, the described in-bcnding of the flames is definite, and is not due to gravity or to the surrounding combustion space wall, but exists when that wall is removed and when the burner axis is either horizontal, or vertical, and in the latter case, whether the axis extends upward or downward from the end of the combustion space at which the combustible mixture is introduced. The atmosphere in the portion of the combustion space atthe inner sides of the flames, depends upon the air-fuel ratio of the combustible mixture, since the invention permits of such efficient combustion conditions, that the oxidizable constituents of the fuel wall practically all combine in combustion with the oxygen of the air if the mixture contains enough air for the purpose, and if not, will combine with practically all of the oxygen in the air content of the mixture. By suitable regulation of the air-fuel ratio in the mixture, it is thus possible to maintain a combustion space atmosphere which is definitely reducing, definitely oxidizing, or neutral, as operating conditions may make desirable.

The rlength of an individual flame, while dependent to some extent upon the B. t. u. value and combustion characteristics of the i'uel in the combustible mixture, and upon the combustion temperatures, depends primarily upon the Jet velocity with which the combustiblemixture is discharged into the combustion space. In the case of any given burner, as the combustible mixture supply pressure is increased to increase the vamount of fuel burned and burner heating effect, the flames are elongated and the angle of divergence of their tips from the burner axis is diminished. The locus of the tip end of the inner cone or body of unburned mixture portion of each flame as its length changes as a result of a supply pressure change, is a curved line within, and to be regarded as the flame axis line, whether the flame is relatively long orrelatively short. The angle of initial jet divergence from' the burner axis, depends upon the form and disposition of the discharge end portions of the channels or orifices through which the combustible mixture is discharged into thev combustion space, and is substantially independent of the supply pressure and flame length. The concavity of the flame to the burner axis increasesl as the length of the flame is increased and i's much more pronounced when the flame yis of its maximum practical length, than when the flame is only half that length. As shown in some of the accompanying drawings, hereinafter described, the angle of divergence of the jets discharged through diametrically opposed channels or orifices, is about and approximately that divergence is especially desirable from the practical standpoint in many cases. This is particularly desirable when the combustion space is open at its larger end to the atmosphere,.or to a space containing an object or material to be heated, and which when heated evolves vapors or gases desirably drawn into the combustion space proper and burned or carbonized as the jet products `of combustion are then made oxidizing or reducing for the purpose.

Since the lateral distance from the axis oi each flame to the immediately adjacent portion of the refractory wall should be about the same all along the length of the flame, the contour of the inner surface of the refractory wall must depend upon and conform to the flame shape, and, as previously pointed out, is cup-shaped in the circular burner unit. With the cup shape combustion space, the heat radiation is mainly away from the end of the combustion space at which the combustible mixture jets are introduced, as is desirable for the transfer of h'eat to the object or space ordinarily to be heated, and also because it tends to avoid over-heating of the portion of the burner structure forming, or in heat transfer relation with, the walls of the supply oriilces or channels through which the combustible mixture jets are delivered to the combustion space. Those oriilce or channel walls should be kept cool enpugh to prevent ignition of the combustible mixture prior to its introduction into the combustion space. To avoid or minimize the need for water cooling, and for the ful1 attainment of the advantages of the invention obtainable with. high combustion chamber temperatures, the Walls .of the orifices at their discharge ends, at least, should be formed wholly or mainly of refractory material having a lower heat conductivity than any practically available metal. s

The cup shape of the combustion space of the circular burner unit is practically desirable, also, in that it reduces the lateral displacement of the outer end portion of each ame from the corresponding portions of the immediately adjacent flames, and thereby minimizes the difference in temperature between the portions of the refractory wall immediately adjacent the flames and the cooler portions of the Wall immediately adjacent the spaces between the adjacent flames. 'I'he heating to incandescence ofthe refractory wall surrounding the combustion space, is desirable not only because of the resultant high rate of heat radiation directly from that wall, but also because it results in higher average gas temperatures within the combustion space, and henCe to an increased flame radiation V.of heat, and also because it assists in maintaining the ignition of the flames under varying conditions of operation tending to cause the flames to blow oil'," and thereby contributes to the high turn down range which is a characteristic and advantageous feature of the burner unit. y

In my elongated burner unit, the combustion space is trough shaped, and the combustible mixture Jets are introduced into the trough shaped combustion space adjacent its bottom side or edge in two rows, and the flames in each row diverge, similarly from the plane which is midway between the two rows, and may be designated as the central plane of the combustion space. The opposing sides of the trough shaped combustion space are not plane surfaces, but each diverges from said central plane at an angle which diminishes as the distance from the bottom of the trough increases. With the trough shaped combustionspace, substantially the same relation between each flame and the immediately adjacent refractory wall portion, is required as with the circular arrangement first described. A section of an elongated burner unit, transverse to its central plane,.may be identical with the diametral cross section of a circular burner unit having supply channels of the same cross section and the same discharge end inclination. The fuel burning4 capacity and heating effect of the elongated unit may exceed the practical maximum obtainable with the circular burner unit, and in some cases where the required capacity is readily obtainable with a circular unit, the

elongated unit may have certain practical advantages fromv the construction standpoint.

The various features of novel-ty which characterize my invention are pointed out and referred to in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages, and various specific objects attained with it, including some not hereinbefore mentioned, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described some of the various forms of apparatus in which the principles of the present invention may be utilized.

Of the drawings:

Fig. 1 is a section of a circular burner unit, taken on the line I-f of Fig. 2;

Fig. 2 is a section on the broken line 2-2 of Fig. 1:

Fig. 3 is a sectional elevation of a somewhat diagrammatically illustrated furnace having a plurality of circular burner units mounted in each of two opposing walls of the furnace chamber;

Fig. 4 is a plan view of a portion of the bottom wall or hearth of the furnace shown in Fi'g'.-3;

Fig. 5 is a section taken similarly to Fig. 1, showing a modified construction; 1

Fig. 6 is a section on the broken line 6-6 of Fig. 5;

Fig. '7 is a vertical section oi a crucible heating furnace;

Fig. 8 is a vertical section of a melting furnace;

Fig. 9 is a section of a portion of a burner having an enclosed combustion space with a portion of its wall adapted for the transmission of tion space into the space into the chamber A',

va radially extending flange Fig. 11 is a partial section on the line ii-il of Fig. 10;

Fig. 12 is a section of a portion of a circular burner unit having a modified form of burner tip:

Fig. 13 is a section on the line Ii-il of Fig. 12

Fig. 14 is a section of elongated burner unit:

Fig. 15 is a side elevation of a portion of the burner tip member employed in Fig. 14;

Fig. 16 is a section of a portion of a circular burner including special provisions for preventing the over-heating of' the burner iet delivery means; 4

Fig. l'l is an elevation partly in'section of another circular burner construction;

Fig. 18 is a section on the line Il-ll of Fig. 1'1;v and ,f

Fig. 19 is a section of a portion of a burner construction comprising a hood or dome over the combustion space formed with outlets for the passage of combustion gases from the combusheated.

The circular burner unit shown in Figs. 1 and 2, comprises a metallic burner body A including a tubular portion surrounding a burner inlet chamber A', to which a combustible gas and air or fuel mixture is supplied at its lower end. through a channel A. The latter, as shown, is coaxial with the chamber A', and passes through a spigot portion of the burner 'body externally threaded for attachment to any suitable fuel mixture supply pipe or supply chamber wall.

Adjacent, but below the upper end of its-tubular portion. the burner body A is formed with A:l forming a support for an annular refractory body B. The latter has its lower portion surrounded by a cylindrical flange portion A* of the burner body which extends upward from the outer edge of the radial` portion A3. The body B may be formed of ceramic material of any composition suitable for its intended purpose.

vSeated on the upper end of the tubular body portion of the burner body A, and extending is a burner tip member C of ceramic material which may be of any suitable composition, such, for example, as anyof the compositions customarily employed in making refractory ceramic burner tips heretofore known. As shown, the member C comprises a main cylindrical portion which extends into, and fits in the outer end of the chamber A', and also comprises an upper cylindrical portion C shorter and of larger diameter than the first mentioned cylindrical portion and the chamber A. and a conical intermediate portion C2. against the beveled upper end Al5 of the main tubular portion of the burner body A. Preferably, and as shown, the lower end portion C1i of the tip member is conical, so as to divert the fuel mixture flowing through the passage A2 into the chamber A' away from the axis of the chamber in a uniform manner.

A multiplicity of peripheral grooves C* are formed in the outer surface of the tip member C. Each of the grooves C4 comprises a portion parallel to the axis of the tip member and extending for the full length of the main cylindrical portion of the tip, and comprises an inclined discharge end portion Cs extending alongside the outer surface of the tapered intermediate section C2 of the tip member to the periphery ofthe upper cylindrical burner tip pora modified form of an member anchored in the The latter bears tion C. As is clearly shown in Fig. 2, each groove C* thus forms a gas passage or orice rectangular in cross section and having three walls formed by the ceramic tip C, and a fourth wall formed by the'adiacent portion ofthe rnetallic burner body A.

Preferably the tip C is anchored in the burner body A, and to that end. in the form shown in Figs. 1 and 2, the body portion of the tip member is formed externally with a screw thread C in threaded engagement with a corresponding screw thread formed on the inner wall of the burner body chamber A'. With theY burner tip burner body, the burner is adapted for operation in any positionne Even when the burner is intended for use only in the upright position shown in Fig. 1, the anchorage of the tip'member in the burner body is desirable,.since under some conditions of use, the gas pressure in the chamber A' may well` be more than sufficient to lift the burner tip member C' out of the chamber A', unless anchored therein'.

The portion B of the inner wall or surface of the annular body B, surrounds and defines a combustion space in which the fuel mixture delivered thereto through the channels or orifices C4, is wholly or largely burned, and maybe described as of cup shape, and may be regarded i las comprising a circular series of surface portions or sectors alongside the jet issuingl from one or each burner channel C. Each of said surface sectors has its portion adjacent the burner body inclined away from the axis a of the burner `at about the same angle as the adjacent burner channel portion C5, and laterally displaced from the axis of that channel portion. In other words, the said portion oi the surface B may be regarded as part of a conical surface, with its apex in the axis a, at some distance below, as seen in Fig. l, the point in that axis at which the inclined channel portions C5, if extended, would intercept said axis.

The inclination' to burner orifice discharge portions C5, serves the purpose of so locating a corresponding sector portion relatively to each flame, or burning jet, formed by the combustion of the fuel mixture vsupplied by each orifice C4, that said surface will be heated to incandescence and with a suitably close approximation to temperature uniformity of all portions of the surface directly alongside the flames, regardless of the actual length of the flames.

The ame lengths, in any given condition of use, will depend upon thefuel composition oi the constituent of the combustible mixture, and with any given fuelcomposition, will be longer or shorter, accordingly, as the gas pressure in the chamber A', and consequently the rate of combustion and total heating effect, are relatively great or relatively small. In Fig. l, the different pairs of oppositely curved lines meeting at the points e', e?, e3, etc., represent the opposed outer sides of the so-called lnnercones of flames or burning Jets of different lengths, such as would ybe produced with successively higher combustible the axis a o each of the v 'said segmental portions of the wall surface B',

lines and arrows in 5 ing jct produced by the combustion of the combustible mixture discharged through the corresponding orice C4. As shown, the lateral displacement of the immediately adjacent portion of the wail B' from the flame axis e, is approxi- Vmateiy the same at all points along the length of said axis.

While the shaping of the surface B' relative to the flame axes e need not be mathematically 16 exact. the general relation illustrated and described'is essential to the attainment of the full advantages of the invention. Although the combustin llames or burning jets are located adjacent the surface B', and are spaced away from the burner axis as described, in normal operation, the entire combustion space surrounded. by the wall B', is filled with burning gases `and hot gaseous products of combustion, which circulate in that space generally as indicated by the curved Fig. 1. In operation, the general direction of ow toward the burner tip member C in the portion of the combustion space adjacent the axis of the burner, can easily be defected. Apparently, hot gases are continuous- 3o ly passing into the portion of the combustion space surrounded by the flames along the portions of the flames relatively remote from the tip member, and gases are continuously passing from said space portion into or between the portions of the flames nearer to the burner tip member. This, coupled with the high combustion efficiency obtainable, permits the atmosphere in the combustion space, to be maintained definitely reducing, oxidizing, or neutral, depending ori the air and fuel ratio of the combus- 40 tible mixture supplied. When vapors or gases are evolved in heating an object or material located in or adjacent the larger end of the space in which said recirculation occurs, those vapors or gases may be drawn by the recirculating burn- C5 ing gases and products of combustion, into admixture with the latter, and burned or reduced, depending on their character, by making the said air and fuel ratio suitable for the purpose.

For the lfull advantage of the present invention, the combustion space, cavity or tunnel surrounded by the wall B', should be of sufllcient axial extent for the combustion of the fuel wholly, or. at least, mainly, within that space. While the inclination to the burner axis of the inclined portions C5 of the burner orifices and of the adjacent portions of the surface B', may be varied through a very considerable range, it is practically essential, as has been indicated, that the angle of inclination should be s'uchthat the space' defined by the wall B' will be definitely cup shaped. The cup-shape of that space contributes to the maintenance of the entire wall B', or with relatively short flames, the zone thereof immediately adjacent the flames, at a temperature high enough to insure efficient combustion conditions and the desired heat radiation. As will be apparent, with the cup .shape of the space defined by the wall B', every portion of that wall is in the position to receive a significant amount of heat by radiation from a portion of the wall of the burner axis. Such radiation of heat to one portion of the wall B' from another portion at the opposite side oi' the burner axis, necessarily diminishes as the space defined by the wall B', is shortened or flattened.

at the opposite side may be maintained suitably cool, as a result of conditions, one of which is the relatively smallamount of heat which can be transferred by radiation from the wall B' to said cylindrical surface as a result of the unfavorable relative disposition of the two surfaces for transfer of radiant heat from the one to the other. A second condition contributing to relatively low burner tip temperatures, is the cooling ellect of the combustible mixture moving through the channels C4. The latter. because of their individual small cross section, necessarily have a relatively large aggregate wall surface area. However, the poor heat conductivity of the refractory material of which the tip member is preferably formed, insures a relatively low rate of heat flow to the relatively cool walls of the fuel channels from the uncooled and much hotter tip member surface exposed within the combustion space.

IBurner units of the general type shown in Figs. 1 and 2 may be combined in various ways to form a gas burner assembly or heating wallhaving a .fuel burning and heating capacity much greater than that of an individual burner unit. For example. one wall. or each of two or more walls, of a heating chamber or furnace may have mounted in it a mulitplicity of burner units of the character shown in Figs. 1 and 2. Thus, as shown in Figs. 3 and 4, the` hearth or bottom wall, and the roof or top wall of a heating furnace E are each composed essentially o' burner units including refractory combustion space wall members BA which are operatively identical with the part B of the burner unit shown in Figs.-1 and 2. To facilitate their assembly in the furnace chamber hearth and roof walls, the bodies BA are rectangular in outline as shown in Fig. 4, and, in each furnace wall including them, the bodies BA are arranged in side by side rows, with the adjacent bodies in each row in abuttingrelation. In the construction illustrated in Figs. 3 and 4, the individual metallic burner body portions. corresponding to the burner body A oi' Figs. 1 and 2, for each row of burner units are rigidly attached to. and may be integral portions of a gas and air mixture supply pipe or manifold AA which extends longitudinally of, and in supporting relation with a corresponding row of burner units.

I'he arrangement shown in Figs. 3 and 4 is plainly characterized by its mechanical simplicity and the relatively large heating capacity which it may have, and by the uniformity with which each wall of the furnace chamber may be heated. The effectiveness of the heat distribution may be augmented by staggering the burner units in the different rows, as shown in Fig. 4. By supplying a greater amount of fuel to the pipes AA adjacent the sides of the furnace E than to the pipes adjacent Athe vertical central plane of the furnace, the side edges of the hearth and roof walls and the vertical side walls of the furnace may be adequately heated. In the practical use of a heating chamber having burner units in its roof wall only, and of a volumetric capai'cty of some 20 cubic feet, I have found it easy to maintain heating chamber temperatures considerably in excess of 2,000 F.. and to vary the rate of combustion in the individual burner llli units through a wide range, in accordance with the desirable rate of heat absorption by the work being heated. l

In a burner unit of the general circular type illustrated in Figs/1 and '2, it is notv essential that the burner tip member should have its cylindrical body portion received in a chambered metallic burner body. Thus,y as shown in Figs. 5 and 6, for example, the' tip member CBmay be mounted directly in an axial passage B21 formed in a refractory body BB which replaces, and serves all the above mentioned purposes of the refractory bodies B and BA of Figs. 1-4.

In a burner in which a refractory burner tip member is mounted directly in the refractory tunnel or body member, as shown in Figs. k5 and.

6, it is immaterial, in general, whether the combustible mixture supply orifices C are formed in the burner tip member, as in the constructions previously formed, or are formed partly in y i the burner tip member and partly in the refractory body member, or are formed wholly lin the latter, as the orifices C10 are formed in the body BB of the burner shown in Figs. 5l and'6. As shown in Figs. 5 and 6, each orifice groove C10 comprises a main body portion parallel to thel burner axis, and a discharge end portion in-` clined to that axis as are the orifice portions C5 of Figs. 1 and 2.

In Fig. 7, I have illustrated the use of the' present invention in a furnace'primarily adapted for heating a small crucible F, though equally well adapted to heat an ingot or other body supported as is the crucible F. The furnace shown in Fig. 7,` comprises a refractory body member BC,` which may be described as of inverted cup form, with its rim resting on a supporting body BC of refractory material formed with passages BC2 for the discharge of products of combustion from the combustion space above the supporting member BC' and surrounded by the body member BC. The latter is formed at its top with an axial opening receiving a burner tip member CC. which may be identical in form with the burner tip member C of Figs. 1 and 2. A metallic gas supply member AC mounted on the upper end of the body member BC. is formed with a gas inlet chamber A10 supplying gas to the upper ends of the orifice grooves C* of the burner. tip member CC. The base member BC' is formed at its upper side with an upwardly extending projection BCT1 on which the crucible F is seated in normal operation. The base and body members BC and BC are made separable for the insertion and removal of the crucible, and as shown, these parts are provided with cooperating sand sealing provisions 13C'1 for preventing leakage through the joint between the member BC and BC.

The inner wall B10 of the member BC may have its upper portion shaped exactly like the portion. adjacent the burner tip of the member B shown in Figs. l and 2. The lower portion oi' the wall B10 is advantageously shaped to conform to the contour of the crucibleF so as to provide a suitably shaped path of downflow along the crucible of the heating gases.

With the burner tip above the crucible, as shown in Fig. '7, the top of the crucible and its contents are directly exposed to the most intense heat radiation from the wall B10, and any molten metal which overflows from the crucible. may pass immediately from the combustion chamber of the furnace through the outlets BC2. Except in respect to the `two features just mentioned, the crucible heating action of the furnace shown in Fig. 'I would not be modified by turning the furnace upside down and seating the crucible on the burner tip member CC, instead of on the projection BC3,frorn the member BC'. Whether the crucible furnace shown in Fig. '7, is arrangedasshown in that figure, or is inverted, full advantage may be had with it of the reducing atmosphere maintained as described in connection with Figs. l and 2, within the portion of the combustion space surrounded by the circular series of flamejets alongside ythe wall B10.

In Fig. 8 I have illustrated the use of the present invention in a melting furnace which resembles the crucible. heating furnace of Fig. '7, in thatit has a burner tipm'ember CD mounted in a central passage lin the top of a refractory body member BD of inverted cup form, and having its rim resting on a supporting member bd. The latter serves as the furnace hearth, and is formed with a cavity bd' in its upper side to re-l ceive the metal to be melted. As shown, the joint between the members BD and bdis normally sealed by cooperating sand seal forming parts BD2 and bd. If the member BD is supported independently of the hearth member bd, and the latter is rotated about the vertical axis of the furnace, the material melted in the hearth cavity bd' may beagitatd by a stationarystir-Y ring member BB3 of suitable refractory metal extending through, and `rigidly vmounted in the body BD.

As shown in Fig. 8, an annular metallic burner body AD is imbedded in the member BD and passes the combustible mixture to the upper ends of the orifice grooves C* of the `burner tip member CD. As shown, the latter is formed with an axial passage CD open at its upper end to the atmosphere. and serving as an outlet for the products of combustion formed in the combustion space of the furnace. The hot gases discharged through passage CD give up heat to, and preheat the fuel mixture passing through the member AD and chamber C1 of the tip member CD, which increases the thermal efficiency of the furnace and increases the flame temperature.

In Fig. 9 I have illustrated a form of my inventionl especially desirable for use in somecases, which differs from the burner shown in Figs. 1 and 2, essentially only in that the end of the combustion chamber remote from the burner tip member, is closed by a heat transmitting wall BE', and in that the burner tip member CE is formed with an axial passage CE' serving the products of combustion discharge purpose of the channel CD of the burner tip member CD of Fig. 9. As shown, the wall member BE is a disc-like plate which may be formed of quartz or of' some heat resistant metallic alloy. If formed of quartz, much ofthe heat radiated toward the wall BE from the inner wall B15 of the refractory body member- BE, corresponding but may be maintained at an operating tempera ture high enough for an intense radiation of heat from its outer surface. With `one or more burners of the general characterv shown in Fig. 9

mounted in the wall of a heating chamber, as the burner units are mounted in the hearth and roof walls of such a heating chamberas is shown in Figs. 3 and 4, the atmosphere within the heating chamber can not be contaminated by prod.- ucts of combustion, but may be formed of inert gas or otherwise controlled, as the atmospheres in electric heated furnaces, and in ordinary muffle furnaces are controlled, where such control is desirable, as in certain heat treating and other industrial heating operations. The furnace chamber BF' shown in Figs. 101 and 11, is surrounded by a tubular refractory body member BF.

The furnace shown in Figs. 10 and 11, includes as its heating means one of my improved burners of the elongated type, formed at one side, its lower side as shown, with a longitudinally extending slot BF2. As shown, the refractory body ,BF is carried by a metallic gas supply member or manifold AF formed with lateral flanges AF' on which the member BF is mounted, and with a gas supply chamber AF2 extending into the slot BF2 and open at one side to receive a portion of the burner tip member CF. The latter in transverse cross section, may be, and is shown as exactly like the burner tip member C of Figs. 1 and 2, except that the bar-like burner tip member CF is not anchored in the metallic burner body member AF by the simple screw thread arrangement employed in Figs. 1 and 2.

The general operative principles of the burner arrangement shown in Figs. 10 and 11, are identical with those of the arrangement shown in Figs. 1 and 2. The discharge ends of the channels C2o are so inclined, and the slot BF2 is of such width, that the inner wall surface BF4 of the portion of the member BF immediately adjacent the flame formed by the combustion of the jet issuing from any of the channels C20, will be displaced from the flame by approximately thesame distance at all points along the length of the flame whether the latter be relatively long or relatively short.

In the elongated burner unit of Figs. 10 and 11, the portion of the refractory wall surface B14 immediately adjacent a flame at one side of the central plane of the burner, receives radiant heat directly from that flame and adjacent flames. and from the directly opposite flames at the other side of the central'plane. and from the opposing wall surface BF. In respect to the radiation characteristic just noted. the elongated burner unit diil'ers from such a circular unit as is shown in Figs. 1 and 2, only as the circular disposition of the flames and refractory wall surface of the last mentioned figures increases the radiation to the portion of the wall surface immediately adjacent any one flame from other flames and the opposing refractory wall portion. The eilect of this relative decrease in the amount of heat radiated to a portion of the wall BFtimmediately adjacent a flame, is compensated for. more or less. by the fact that in the .elongated burner unit the axes of adjacent flames are parallel and not divergent, as is necessarily the case'in the circular burner unit.

The modified circular burner unit construction shown in Figs. 12 and 13, while comprising a burner body AG which may be identical in form with the burner body A of Figs. 1 and 2, includes a burner tip member CG differing in the form of its orifices or supply channels C25 from the tip member C i'lrst described. The channels C25 of the tip member CG are in the form of kerfs or slots, each extending radially of the member CG toward its axis. merging adjacent said axis into a central axial passage C. The slots C and passage C extend longitudinally of the member CG from a short end portion of the latter adjacent its combustion space end to the opposite end of the member.

In the elongated burner unit construction shown in Figs. 14 and 15, the refractory body n BH Ahas its opposed combustion space wall surfaces BH, each in the form of a segment of a cylinder, the combustion space being open at its side remote from that at which the combustible mixture jets are introduced. Except in respect to the form of its refractory body member, the burner construction of Figs. 14 and 15 is generally equivalent to the burner arrangement of Figs. 10 and 11, but differs from the latter in' the form of the burner tip member CH. The latter is an inverted trough shaped part having parallel sides CH externally cut away, adjacent the open side of the `trough space'to provide recesses CH2 respectively receiving portions of the opposite sides AH of the burner body member AB. which is shown as of trough form.v The sides CH' of the member CH are each formed with a multiplicity of side by side kerfs or slots C30, each of which forms one of the supply channels or orices through which the combustible mixture is passed into the combustion space.

If the burner tip members CG and CH shown in Figs. 12-15 are formed of metal, their orifice slots or kerfs C25 and C30, respectively, maybe formed by a milling cutter. or other metal cutting machine. 'I'he tip members CG and CH may also be formed of ceramic material by simple molding operations, which, as those skilled in the art will understand, may be performed in molding apparatus including metal plate core' portions forming the orifice kerfs or slots.-

As'has been made apparent. the full advantages of the present invention can not be obtained with burners operating at temperatures as high as are required for many industrial operadestructive of tip members of any available metallic material, and even though such metallic burner tip members are not exposed to temperatures high enough to prevent the members from retaining'A their general form during a considerable operating life, the members are nevertheless subject to distortion and to surface corrosion preventing the maintenance ofthe desired orifice forms and dimensions. For certain low temperature work, however. reasonably satisfactory operating results can be obtained with metallic burner tip members, and the relative ease with which burners including metallic tip members of the form shown in Figs. 1215, canbe constructed. make the use of such metallic bur'ner tip members especially advantageous in the case of special burner unit assemblies ofsizes and forms for which no molded refractory tip members are available.

The burner construction shown in Fig. 16 includes two expedients, each of which may be used without the other to minimize the heating of the walls of the vsupply orices or channels. One of saidexpedients is the heat insulation of the exposed end of a metallic burner tip member, by ineans of a refractory cover CG1 therefor. The second expedient is the water cooling of a metallic portion ofthe burner. These expedients, while of themselves complicating and adding something to the cost of the burner construction, permits the use of metallic parts forming the walls of said channels, under burner temperature .conditions which would otherwise be prohibitive of the use of such metallic burner parts.

'I'he burner form illustrated by way of example in Fig. 16, is generally similar to that shown in Figs. 12 and 13. and includes a burner tip member CG shown as identical with the member CG of Figs. 12 and 13, but is provided with a heat insulating cap member C610. The latter is a body of refractory heat insulating material suitably adapted for mounting on the combustion space end of the metallic tip member CG, so that the heat directly received by said end, is only such heat as is conducted to it through the cap member.

The metallic burner body member AI of Fig. 16 diff ers from the corresponding member AG of Figs. 12 and 13, in that the wall of its tubular portion is formed with an annular channel A110 surrounding the axis of the burner and extending nearly to the combustion space of the part AI. Inlet and outlet connections AIl1 and AIl0 are provided for the circulation of water or other cooling fluid through the channel A110. Advantageously, the refractory body BI of the burner unit shown in Fig. 16 is shaped to provide a portion BI extending over the portion of the wall of the channel A110 immediately adjacent the combustion space. The burner construction shown in Figs. 17 and 18, comprises a burner tip member CH, the coing bustion space end of which may be like that of the burner tip member C shown in Figs. 1 and 2 in that it comprises a,conical surface C50 and inclined orifice grooves C01 like the surface C0 and groove portion C4 of Figs. 1 and 2. In the burner shown in Figs. 17 and 18, however, the burner tip surface C bears against a conical seat formed in the end of a tubular body ch of refractory material surrounding a shank portion C52 of the burner tip member. Said shank portion might be circular in cross section, but advantageously and as shown, is polygonal in cross section, and in .either event, is of a cross section smaller than that of the bore in the tubular member ch. As shown, the latter is formed with internal axially extending ribs C03, which space the shank C50 axially of the member ch., and divide the space between the shank and the member ch into a number of supply channels C which may be and as shown'is appreciably ysmaller than the number of discharge orifices C51. As shown, the refractory sleeve element ch is anchored on the tip member CH by means of a nut C00 threaded on the shank at the inlet side of the burner.. The burner element comprising the parts CH, ch, land C, may be mounted in a metallic burner body generally like the metallic burner body A shown in Figs. 1 and 2, or in some analogous metallic or refractory material burner body. As shown, the end of the sleeve ch against which the nut C00 abuts, is formed with radially extending inlet grooves C6 communicating at their inner ends with the bore of the member ch.

The burner construction illustrated in part in Fig. 19, comprises a burner tip member C, a metailic body member AA, and a burner body member BI of refractory material, all generally like the parts C, AA and BB of the construction shown in Figs. 3 and 4. The ypart AA is shown as formed with a cooling fluid channel A110 in the tubular portion into which the burnertip member C extends, with inlet and outlet connec-n tions AI*1 and A110 to the channel A110, as in the construction shown in Fig. 16. In Fig. 19, however, a dome or hood bi of 4heat resistant material, extendsl over the Vend of the combustion space in the burner body BI remote from the tip C, with the baseof the hood fitting around a rib bi', with which the burner body BI is provided to center the dome or hood. The latter is Iformed with ports bi for the passage of products of combustion from the combustion space into the space to be heated. The burner construction shown in Fig. 19, while not limited to such use, was primarily devised for incorporation in the hearth of a furnace chamber such as that shown in Figs. 3 and 4. In such use, the hood member bi serves to prevent scale or furnace dust from dropping into the burner combustion space. With the hood member bi formed of transparent quartz, much of the 'heat generated in thecombustion space may be directly radiated into the furnace chamber, but with the hood bi formed'of heat resistant metallic alloy material, such direct radiation of heat is prevented, and the heat not carried into the furnace chamber by the products of combustion, will be delivered to that chamber by conduction through the hood, and emitted from the convex side of the latter.- 4

While as has been explained, it is ordinarily immaterial whether the general direction of gas i'low in the combustion space is up, or down, or horizontal, it is convenient to refer to the portion of the combustion space at which the combustible mixture is introduced,'as the bottom portion of said space, whether the latter be cup shaped as shown in Figs. 1 and 7, for example, or be trough shaped, as shown in Figs. and 14,/for example. Whether the combustion space is cup shaped, or trough shaped, the supply channels through which the combustible mixture is supplied to the combustion space open to the latter at points distributed along the margin of a bottom portion of said space, and the burning Jet formed by the mixture delivered through each channel, is adjacent and alongside a section oi' the combustion chamber wall which extends ,away from the bottom portion of the combustion space and is formed by refractory material, so that the said sections may be heated to incandescence by the burning jets.

The present application is a continuation in part of, and claims subject matter disclosed Iin my prior application Serial No. 42,994, led October 1, 1935. Certain combinations including a' vheat transmitting body interposed between a burner combustion space and a space to be heated, shownl in Figs. 9 and 19 hereof, but not claimed herein, are claimed in my application for patent, Serial No. Sli-8,325, illed July 29, 1940, and constituting a continuation'in part of this application. Certain novel features of furnace construction and arrangement including burners incorporated in the furnace chamber wall and constructed in accordance with principles Idisclosed herein, are claimed in my copending application, Serial No. 106,208, illed October 17, 1936.

While in accordance with the provisions of the statutes, I have illustrated and described the best forms of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in said forms without departing from the spirit of my invention as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a correspond- .ing use of other/features..

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1 A gas burner having a combustion space increasing in cross section with the distance from the bottom thereof, and including means for passing a combustible air and gas mixture into said space including a multiplicity of supply channels opening to said space at distributed points adjacent the margin of a bottom portion of said space, so that the mixture discharged by said channels may form burning jets respectively adjacent and alongside sections of the wall of said space extending away from its said bottom portion, and including vrefractory material forming the said wall sections so that the latter are adapted to be heated to incandescence by said Jets, the discharge end portions of said channels and said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of the burning jets against said wall sections and said space having a bottom wall substantially impervious to air flow into said space except through said channels.

2. A gas burner as specified in claim l, in which the walls of the discharge end portions of the mixture supply channels are formed in large part, at least, of refractory material.

3. A gas burner having a cup shaped combustion space and including ,means for passing a combustible air and gas mixture into said space, said means comprising a multiplicity of supply channels opening to said space at points adjacent the bottom, and distributed about the axis, of said space, so that the mixture entering the space through the different channels may form burning jets respectively adjacent and alongside corresponding sections of the wall of said space which extend away from the bottom of the latter, and including refractory material forming the said wall sections, so that the latter are adapted to be heated to incandescence by said jets, the discharge end portions of said channels and said wall sections being relatively shaped and disposed to avoid impingement of the inner ame cone portions of the burning jets against said wall sections and said space having a bottom wall substantially impervious to air ow into said space except through said channels.

4. A gas burner, tip member of refractory material comprising an externally threaded cylin- A drical body portion and a-n enlarged head and formed with grooves, each comprising a portion at the periphery of, and extending longitudinally of, said body portion, and a portion at the side of said head adjacent said body portion, and extending to the periphery of said head portion.

5. A gasl burner having a trough shaped combustion space increasing in cross section with the distance Afrom the bottom thereof, and including means for passing a combustible air and gas mixture into said space including a multiplicity of supply channels opening to said space at points distributed along opposite sides of a bottom portion of said space so that the mixture discharged by said channels may form burning `iets respectively adjacent and alongside sections of kthe side walls of said space extending away from its said bottom portion, and including refractory material forming the said wall sections, Awhich are adapted to be heated to incandescence by said `iets, the discharge end portions of said channels and said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of the burning jets against said wall sections and said space having a bottom wall substantially impervious to air ow into said space except through said channels.

6. A gas burner having a combustion space increasing in cross section with the distance from the bottom thereof, and including means for passing a combustible air and gas mixture into said space including a multiplicity of supply channels opening to said space at distributed points adjacent the margin of a bottom portion of. said space, so that the mixture discharged by said channels may form burning Jets respectively adjacent and alongside sections of the wall of said space extending away from its said bottom portion, and including refractory material forming the said wall sections, so that the latter are adapted to be heated to incandescence by said jets, the discharge end portions of said channels and lsaid wall sections being relatively shaped anddisposed to avoid impingement of the inner fiame cone portions of the burning jets against said wall sections, notwithstanding a variation in the velocity of mixture ow through said channels suiiicient to vary the length of each jet from a minimum operative length to a maximum Ioperative length at least double said minimum length and said space having a bottom wall substantially impervious to air flow into said space except through said channels.

7. A gas burner unit comprising a body formed with an inlet chamber and with an opening to said chamber at one side thereof and having an external surface at the margin of said opening and inclined away from said one side, a refractory burner tip member having a portion extending into said opening and having an inclined surface parallel to, a-nd engaging said inclined body surface and having surface grooves, the walls of which unite with said body to form burner outlet channels from said chamber, each of said channels having a discharge end portion one side wall of which is formed by the inclined surface of said body member, said body including refractory material defining a combustion space into which said channels discharge and having combustion wall surface portions respectively extending away from and generally parallel to the l direction of the burning jets of combustible mixture discharged into said comb-ustion space through the different channels.

8. A gas burner unit as specified in claim 7, in which the said chamber and burner tip member are circular in outline and have a common axis, and the said inclined surfaces extend circularly about said axis.

9. A gas burner unit as speciiied in claim 7. in which the said opening has parallel elongated side edges and said tip member is a bar like body and the said surface grooves a-re formed in the opposite-side of said bar like body, and in which there is one set of said inclined surfaces at one side, and a second set of said surfacesat the opposite side of said opening and bar like body.

10. A gas burner unit as specified in claim 7,

including means for releasably securing the said burnerl tip member in the said chamber of the said burner body. o 11. A gas burner unit as specified in claim 7, in which the chamber entering portion of the burner tip member is circular in cross section and externally threaded.

l2. A gas burner unit as specied in claim 7, in which the said burnerbody includes a metallic iiange portion parallel to, and spaced away from the said side of the said chamber at which the in whichl the said burner saidopening is formed. and infsupporting en-` gagement with thesaid refractory material of theunit. f f

13. A gas burnerunitas specified. in claim 7,

n body includes a metallic portion formed with a cooling fluid passage external to the said lchamber in said body member. v, f A j 14. A gas burner unit comprising a metallic body member including a rounding an inlet chamber open at one end and having a conical end surface extending away fromsaid chamber` at its open end, a. burner tip member of ceramic material formed with a cylindrical portion extending into said chamber through the open end thereof and an outer portion.` of larger cross section with a conical surface seating against the said' conical surface of said body member and formed with surface grooves, eachfof said grooves leading from` the portion of said chamber at the inner side of said tip member and having an inclined discharge end por' tion alongside said conical end surface, and an annular body of ceramic material surrounding said tubular portion and tip member and having a conical inner wall surface surrounding'and defining a conical combustion chamber into which said grooves discharge.

15. A gas burner comprising means providing a series of flame-projectingl orifices directed outwardly along a conicalsurface, and means comprising a refractory member having a generally conical inner wall extending substantially parallel-to the flames .projected from said orifices andv cooper-ating with the first mentioned means to form a conical combustion space substantially closed at its smaller end against inflow of air except through said orifices.

16. A gasy burner having at opposite sides thereof flame-projecting orifices directed in lines diverging at an angle substantially less than 180, so that-flames projected from said orifices tend to curve toward one another, and a wall vsurrounding a combustion space into which said orifices open adjacent one end of the space, said space being substantially closedl at said end against fluid flow into the space except through said orifices, said wall comprising refractory material having its inner surfaces at opposite sides of the burner diverging at substantially the same i angle as the orifices and slightly curved so as to parallel said curved flames.

17. A gas burner having a combustion space increasing in cross section with the distance from the bottom thereof and having a combustible air and gas mixture supply chamber extending away from said combustion space at the bottom of the latter, and a burner tip member having a body portion extending into Asaid chamber and an en larged head portion in said combustion space,

the wall of said chamber and said member hav-- ing contacting surfaces, one of said surfaces being grooved to form a multiplicity of supply channels through which the combustible mixture passes into said space from said chamber, said channels opening to said space at distributed points adjacent the margin of a bottom portion of said space so that channels may form burning jets respectively adjacent and alongside sections of the wall of said space extending away from its said bottom portion, and including refractory material forming the said wall sections so that the latter are adapted to be hea-ted to incandescence by said jets, the discharge end portions of said channels and said tubular portion surthe mixture discharged by said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of the burning jets'against said wall sections.

. 18. A gas burner having a combustion space increasing in cross section with the distance from the bottom thereof and having the bottom wall of the combustion space formed with an opening outwardly flared-to provide an inclined seat surface, and including means forl passing' a combustible air and gas mixture into said space comprising a burner tip member having a body portion extending into said opening and an enlarged head portion in said combustion space, and formed with a surface adapted to fit against said seat surface, one of said surfaces being grooved to form a multiplicity of supply channels through which the mixture passes into said space, said channels opening to said space at distributed points adjacent the margin of a bottom portion of said space, so that the mixture discharged by said channels may form burning jets respectively adjacent and alongside sections of the wall of said space extending away from its said bottom portion, and including refractory material forming the said wall sections so that the latter are adapted to be heated to incandescence by said jets, the discharge end portions of said channels and said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of the burning jets against said wall sections.

19. A gas burner having a combustion space increasing in cross section with the distance from the bottom thereof and having a combusf tible air and gas mixture supply chamber extending away from the bottom of the latter, and a burner tip member having a hollow body portion extending into said chamber and an enlarged head portion in said combustion space and formed with kerfs which extend through a wall of said hollow body of saidl the burner combustion space at tion, and including refractory material forming the said wall sections so that the latter are adapted to be heated to incandescence by said jets, the discharge end portions of said channels and `said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of the burning j ets against said wall sections.

20. A gas burner having a combustion space increasing in cross section with the distance from the bottom thereof and having a combustible air and gas mixture supply chamber communicating with and extending away from said combustion space at the bottom of the-latter, and a burner tip member extending across said chamber at the combustin space side of the latter and comprising a, metallic portion and refractory material at the side of said metallic portion remote from said chamber, and having said metallic portion shaped to provide a multiplicity of supply channels through which combustible mixture passes into said space from said chamber, said channels opening to said space at distributed points adjacent the margin of a bottom portion of -said space, so that the mixture discharged' by said channels may form burning jets respectively adjacent and alongside sections of the wall of said space extending away from its said bottom portion, and including refractory material forming the said wall sections sovthat the latter are adapted to be heated to incandescence by said Jets, the discharge end portions of said channels and said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of the burning jets against said wall sections.

21. A gas :burner as specified in claim 17, in which the burner tip member is formed/frefractory material andthe channels through which the combustible mixture passes into the combustion space are formed by surface grooves in the body portion and at the underside of the head portion of said burner tip member.

22. A gas burner having a cup shaped combustion space and having an opening circular in cross section in the bott-om wall of said space and Pincluding means for passing a combustible air and gas supply mixture into said space through said opening comprising a 4burner tip member of refractory material, circular in cross` section, and comprising a body portion extending into said opening and an enlarged head in said combustion space and having surface grooves forming a multiplicity of .supply channels through which said mixture passes from said chamber into said space, said channels opening to said space at points adjacent the bottom, Vand distributed about the axis, of said space, so that the mixture entering the space through the different channels may form burning Jets respectively adjacent and alongside corresponding sections of the wall of said space which extend away from the bottom of the latter, and including refractory material forming the said wall sections.

so that the latter are adapted to be heated to incandescence by said jets, the discharge end portions of said channels and said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of 5 the burning jets against said wallsections.

23. A gas burner having a trough shaped combustion space increasing in cross section with the distance from the bottom thereof, and having a ,combustion space bottom wall' formed with a 10 slot and with an inclined'surface at each side of the slot at the combustion edge of the latter and including means for passing combustible air and gas mixture Jets into said space through said slot comprising a burner tip member having a body portion extending into said slot and an enlarged head portion in the combustion space and formed with a surface at each side of the slot parallel to. and in abutting relation with the corresponding inclined surface, one of the said surfaces at each side of the slot being grooved to form a multiplicity of supply channels through which the said combustible mixture jets are passed into said com-bustion space, said supply. channels opening to said space at points distributed along opposite sides of a bottom portion of said space so that the mixture discharged by said channels may form burning jets respectively adjacent and alongside sections of the side walls of said space extending away from its said bottom portion,l and including refractory material forming the said wall sections, which are adaptedl to be heated to incandescence by said jets, the discharge end portions of said channels and said wall sections being relatively shaped and disposed to avoid impingement of the inner flame cone portions of the burning jets against said wall sections.'

FREDERIC 0. I-IESS.