US2806522A - Combustion burner and nozzle construction - Google Patents

Description

p 1957 c. J. STALEGO 2,806,522

COMBUSTION BURNER AND NOZZLE CONSTRUCTION Filed April 3, 1955 2 Sheets-Shet 2 INVENTOR. CHARLES J. STALEGO BY )MY@ ATTYS.

Unite COMBUSTIQN BURNER AND NOZZLE CQNSTRUCTION Application April 3, 1953, Serial No. 346,622-

6 Claims. or. 158-116) This invention relates to nozzle or orifice construction for a combustion burner construction wherein a mixture of fuel gas and air or other oxidant are burned within a combustion chamber and the products of combustion discharged through a restricted orifice or nozzle in the form of an intensely hot, high velocity gaseous blast.

Burners of this character are particularly adaptable in the glass industry and more especially are employed for producing gaseous blasts for forming very fine fibers from bodies of glass. For example, glassrods or primary filaments are fed into a high velocity blast of intensely hot gases in a manner whereby the rods or filaments are softened by the heat and the softened glass: attenuated or drawn into extremely fine fibers by the velocity of the blast. The intensely hot gases are projected through a restricted orifice at very high velocities of several hundred rates PatentO feet per second. A burner of the general character used for the above purposes is shown in my prior Patent No. 2,489,243, issued November 22, 1949.

A burner of the internal-combustion type has an elongated combustion chamber linedwith suitable re fractory, and the nose or orifice portion of the burner is usually formed of a very high temperature refractory material. While burners of this character have been in use commercially for some time for producing fibers from heat-softenablc material, the burners have been com paratively short-lived as the gases and the high velocities cause comparatively rapid deterioration, corrosion, fracture and Wearing away of the refractory material of the nose portion forming. the walls of the gas passage or orifice. The interior walls of the nose portion converge to define the restricted orifice and hence the velocities of the gases increase at these zones, a condition which accelerates the corrosionand wearing away of the orifice walls.

The temperatures interiorly of the nose portion of a burner may be several hundred degrees higher than the temperatures at the exterior Walls of the nose port-ion ofthe burner, and such temperature differentials cau'seexpansion and contraction, fostering fracture or cracking of the nose portion usually transversely of the orifice. When such fractures or cracks terminate at the orifice walls, the zones of the orifice walls adjacent the fractures wear away or deteriorate at a. very' high rate, and in a comparatively short time the orifice contour ismodified or changed to an extent as to seriously impair the burner or render it useless for fiber-attenuating operations. gravated wear of the orifice at a particular zone increases the orifice width at said zone, and this results in a substantial decrease in the blast velocity at the zone of wear; hence, the blast velocity is rendered nonuniform throughout its cross-sectional area and fibers attenuated thereby are not of uniform size.

The present invention resides in a burner construction wherein the portion of the burner containing. the gas discharge orifice is constructed ofa material and: is of a configuration to resist tendency tofracture under high high temperatures of the 7 ice j temperatures and to withstand Wear and deterioration by the gases moving at high velocities.

An object of the invention is the provision of an orifice or nozzle structure for use with an internal-combustion burner wherein the structure is mounted or supported in a manner facilitating expansion and contraction thereof substantially independently of the expansion and contraction of other components of the burner.

Another objectof the invention is the provision of a nozzle construction fashioned of high-temperature refractory material for use with an internal-combustion burner which is of comparatively thin-walled construction arranged to be readily removed and replaced andis mounted in a manner to provide for substantially unrestricted contraction and expansion relative to its support.

7 Another object is the provision of an orifice construction for an internal-combustion burner formed of materials such as metallic oxides having characteristics resisting thermal and mechanical shock whereby the useful life of a burner orifice construction is greatly lengthened.

Another object of the invention is the provision of an orifice arrangement for use with high-temperature gases wherein the orifice construction is formed of two or more metallic oxides fused together wherein one may have good'thermal and mechanical shock resistance and others endowed with good erosion. resistance characteristics and which, when. combined, provide a construction which is highly resistant to thermal shock and to wear and erosion of rapidly moving gas streams.

A- further object of the invention resides in an orifice construction for use in guiding or directing high-temperaturegases at high velocities wherein the base material of the orifice construction has a high thermal shock resistance and which may be coated or provided with a protective surface of an oxide or mixture of oxides having high resistance to erosion and abrasion.

Still another object is the provision of a refractory composition composed of metallic oxides joined or fused together and which has improved resistance characteristics to thermal shock, erosion and abrasion, rendering the composition or construction particularly adaptable as a wall or lining for chambers or passages subjected to streams of gas of comparatively high temperaturesmoving at high velocities.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be" apparent from a consideration of the specification and drawing ofa form of the. invention, which may be preferred, in: which: Figure l is a longitudinal sectional View through a combustion burner embodying a form of the invention;

Figure 2 is an elevational view' of the orifice end of the burned shown in Figure l;

Figure 3 is a fragmentary sectional view of the forward portion of a burner illustrating a modified form of orifice or nozzle construction;

Figure 4 is a fragmentary sectional View illustrating another form of orifice construction;

Figure 5 is an isometric view of the orifice construction shown in Figure 4;

Figure 6 is an elevational view of an orifice construction formed of component elements; a

Figure 7 is 'a vertical sectional view taken substantially on the line 77 of Figure 6;

Figure 8 is an elevational view of a burner illustrating another form of orifice construction;

Fig. 9 is a sectional view taken substantially on the line 99 of Figure 8, and

Figure illustrates a further form of nozzle constru-ction.

The burner construction is especially adapted for producing intensely hot, high velocity blasts of gases through the combustion of a fuel and air mixture within the combustion chamber and such blasts projected through orifice constructions of the present invention are particularly usable for attenuating bodies of heat-softenable material to fibers. It is to be understood that the nozzle or orifice constructions of the present invention may be used with other apparatus or in any manner where the same may be found to have utility.

Referring first to Figures 1 and 2 of the drawings, there is illustrated a burner and one form of nozzle construction especially shaped or configurated for projecting intensely hot, high velocity blasts into contact with bodies of heat softenable material for attenuating the material to fine fibers. The construction shown is especially suitable for forming fine fibers or filaments from glass. In such use a plurality of streams of heat-softened glass is delivered through orifices in a feeder (not shown) and the streams solidified into primary filaments or bodies which are guided by guide means 17 into a blast B of intensely hot gases moving at high velocity from a combustion burner 20. The extremities of bodies 15 of fiber-forming material continuously delivered into the blast B are softened by the heat of the blast and the softened material drawn out by the velocity of the gases of the blast to form fine fibers.

The burner 20 illustrated in Figures 1 and 2 is inclusive of a metal shell or casing 22 enclosing a refractory body 24 which may be provided with an inner liner 26 also of refractory material, the interior wall of which defines or forms a combustion chamber 30. One end of the chamber is provided with a wall 32 having a plurality of passages or ducts 34 extending therethrough. The opposite end of the chamber is formed with a wall or nozzle base 38 of high-temperature refractory material which is provided with a restricted passage 40 aligned with an outlet or orifice 41 formed in a nozzle construction 42 as shown in Figure 1.

The rear portion of the burner is provided with a fitting 46 adapted for connection with a tube or pipe 48, the latter conveying a gaseous mixture, for example, a mixture of combustible gas and an oxidant such as air, into the manifold chamber 50 contained in the fitting 46. The combustible mixture of fuel and air, under a low pressure of from one to five pounds per square inch, is delivered into the combustion chamber 34 through the passages 34 and the mixture ignited in the chamber 30.

The combustible is substantially completely burned Within the chamber, and the products of combustion undergo great expansion in the chamber 39. The products of combustion are projected through the passage 40 and the orifice 41 in the nozzle construction 42 which is of restricted area so that the intensely hot gases are projected through the-port at a high velocity,. the heat of the gases being upwards of 3000 F. or more, a temperature readily capable of softening filaments of mineral material and attenuating the material to fibers or filaments, or for other uses when an intensely hot, high velocity blast of gases may be desirable or necessary.

In the form of construction illustrated in Figures 1 and 2, the nozzle or orifice member 4-2 is of elongated configuration, and the orifice 41 therein is of generally rectangular shape in cross section. The nozzle member 42 is fabricated of material which is especially resistant to thermal shock and destructive erosion and which resists wear caused by rapid movement of the intensely hot gases through the orifice 41. By forming an orifice construction or nozzle as an independent element as illustrated in Figure 1 and mounting the same in the forward wall or nozzle base 38 of the burner construction, the nozzle is capable of limited contraction and expansion substantially independent of the wall or nozzle base 38. Such arl rangement avoids or substantially minimizes corrosion, distortion and the tendency of the nozzle walls to fracture.

It has been found that the method of mounting an independent nozzle member in the nose portion or nozzle base of the burner provides, in effect, a floating nozzle which, having comparatively thin walls, has greater resistance to thermal shock and has less tendency to fracture than prior constructions wherein the restricted orifice or gas passage outlet was formed directly in the nose portion or front wall of the burner. While the prolonged life and improved wearing qualities of the independent nozzle may be due to several factors, it has been found, as a result of actual operation of such nozzles having comparatively thin walls defining the orifice, that the walls may expand and contract substantially independently of the wall 38 of the burner and hence are not readily susceptible to fracture under thermal and mechanical shock. Furthermore, the walls of the nozzle, being comparatively thin, are not subjected to high temperature differentials between the inside and outside surface zones thereof so that internal stresses set up by reason of temperature differentials within the nozzle unit are greatly reduced over the stresses existent in a comparatively thick-walled orifice construction.

The nozzle construction 42 shown in Figure l is preferably formed with projected flanges, ridges or keys 52. The nozzle base 38 of the burner construction is configurated with recesses adapted to receive and accommodate the keys or ridges 52 to retain the nozzle construction 42 in proper position relative to the nozzle base 38. The slotted or recessed configuration in the nozzle base or Wall 38 extends transversely of the wall and entirely therethrough so that the orifice construction or nozzle 42 may be slidably inserted into the slot in a direction transversely of the longitudinal axis of the burner. The nozzle 42 may be fitted snugly into the slot in the wall 38 so that additional securing means may be unnecessary. If desired, the nozzle construction may, however, be cemented at its end zones in the slotted configuration in wall 38 in order to positively avoid transverse displacement of the nozzle.

The nozzle construction 42 may be formed of various materials and the materials that have been found most satisfactory for the purpose are those which are comparatively dense. Molybdenum silicide has been found to be very satisfactory as it has high resistance to thermal shock and has excellent wear-resistant characteristics. Other dense materials usable for the purpose are platinum, platinum-rhodium alloys and metal ceramics. Metallic oxides and other suitable materials having high fusi on temperatures, such as beryllium oxide, chromium oxide, zircon, boron carbide, tungsten carbide, Kennametal, stabilized calcia, tin oxide and silicon carbide and the like, may be used as well.

More specifically, it has been found that an alloy comprising substantially by weight 60% molybdenum, 30% silicon in the form of molybdenum silicide and about 10% iron provides a most satisfactory material which is highly resistant to mechanical and thermal shock, corrosion, erosion and distortion as well as having improved wearing qualities when subjected to hot gases moving at high velocities. The nozzle base or wall 38 is preferably formed of materials having high resistance to thermal and mechanical shock. Materials suitable for the purpose are silicon carbide, aluminum oxide and beryllium oxide. While these materials are highly resistant to thermal and mechanical shock, they are susceptible to erosion and corrosion when subjected to intensely hot gases moving at high velocities.

It has been found that wear of the orifice wall surfaces may be substantially reduced by applying a coating of an oxide which has high corrosion resistance to the orifice wall of the nozzle construction. Coatings of the following oxides have been found satisfactory to resist corrosion: manganese oxide, iron oxide, calcium oxide, chromiurnoxide, nickel oxide, titanium dioxide and tin oxide.

' of the longitudinal axis of the nozzle.

Figure? illustrates. a modified form; of floating nozzle or orifice construction mounted in t-he. nozzle base or front wall 38a of the burner construction; The nonle 55 is elongated transversely of the burner, in the manner of the construction shown in Figure 2, to form an elongated, restricted orifice or outlet 56 through. which intensely hot burned gases are projected from. the combustion. chamber 30 of the burner. The upper and lower exterior walls 58 and 59 of the nozzle c'onstructionare flared outwardly and rearwardl'y as indicated at 60 and are preferably of arcuate or curved configuration as shown in Figure 3.

The nozzle base member or front burner wall. 38a is configurated transversely of the burner. with slots of a shape reciprocal tothat of the exterior surfaces 58 and 59 and the projecting or flared portions 60. Through this arrangement or method of mounting, the nozzle 55 may be slidably inserted in the slot transversely of the burner and in assembled position is disposed as shown in Figure 3. The nozzle base or wall 38a maybe made of the materials hereinbefore mentioned in connection with the arrangement disclosed in Figures 1 and 2,, that is, materials having high resistance to both mechanical and thermal shock.

The nozzle or orifice construction 55 may be made.- of the relatively dense materials hereinbefore enumerated in connection with the description of nozzle 42,. such materials having high resistance to wear under the heat and velocity of the blast of gases. The interlocking relation of the flared portions 60 in reciprocally shaped zones in the wall 38a serves to retain the nozzle construction 55 in operative position with respect to the wall- 38a. The nozzle construction is capable of independent expansion and contraction relative to the base or wall 38a. As the nozzleis formed with comparatively thin walls, the tendency for. the walls to fracture under the intense heat of the gases is substantially eliminated and the life of the nozzle greatly prolonged.

Figures 4 and 5 illustrate another form of nozzle or orifice construction for a combustion burner. In this form, the orifice or nozzle construction 65 may be fashioned generally tubular in shape and of substantially annular cross section and is provided: with ridges or projections 67 extending in opposite directions transversely The nozzle construction 65 is elongated, as shown in Figure 5, and is preferably formed as a length of an extruded tube of the cross section shown in Figure 4. The Walls of the tube may be machined or fashioned with aligned openings 70 which provide an orifice or outlet for the passage of gases from the combustionchamber 30.

The nozzle base or front wall 38b of the burner is formed with a transversely slotted configuration which is the reciprocal of the exterior shape of the nozzle construction so that the nozzle may be assembled by slidable movement thereof transversely of the burner in the slot formation in the base member 3812 which is. adapted. to receive the nozzle construction. The projections or keys 67 formed on the nozzle provide an interlock with the walls of the nozzle base 38b to prevent displacement of the orifice construction. As shown in Figure 5 the end portions of the tubular member from which the orifice construction is fashioned are closed by means of cylindrical plugs or elements 73 which maybe fused or otherwise fixedly secured inthe tubular section.

This form of orifice construction may be fashioned from extruded tubing, and. the tubing may be cut to the required dimension. for the particular length of orifice or outlet desired. The nozzle construction may be formed of therefr-actories or metallic oxides hereinbefore mentioned in connection withthe other forms of the invention but is preferably fashioned from a tube of metal ceramic such as thorium oxide, aluminum oxide, zirconium silicate or of platinum or platinum alloys.

In Figures 6 and 7 there is illustrated another form of nozzle 01 orifice construction. In the form shown the nozzle construction 75 is formed'of several components or parts which are preassembled and inserted asa unit in: a suitable slotted configuration formed in the nozzle base or wall38'c. The orifice construction 75 is formed of upper and lower longitudinal sections 76 and 77' be tween: which are disposed end sections or elements 78 and 79; The upper and lower sections 76 and 77 are formed with: longitudinally extending ridges, projections or keys 80 which fitinto the slotted configuration: formed in the nozzle base 38c. The end sections 78 and 79" are each provided: with projections 82 which extend into suitable openings formed in the sections 76 and 77 and serve toproperly position the end section's relative to the upper and lower sections 76' and 77. The'projections 82 may be of rectangular configuration to prevent rotatable displacement of the end sections; 78 and 79, although the engagement of the rear walls of the end sections with a wall of the slotted configuration in the nozzle base 380 .will serve to prevent rotational. displacement of the end sections.

The upper and lower sections 76 and 77 and the end sect-ions 78 and 79 are" first assembled together, and the assembly is inserted transversely of the base 380 in the slotted configuration formed therein. When assembled, the upper and lower sections and the end sections of the nozzle construction define an elongated orifice or outlet 84 through which the gases from the burner are projected as a high velocity blast. By fabricating the nozzle construction of several components in the-manner illustrated in Figures: 6 and 7, each component is substantially independent and therefore is capable of expanding and contracting without causing fracture of an adjacent component or part. The components of the nozzle construction shown in Figures 6 and 7' may be made of. the materials hereinbefore mentioned in connection with the other forms of the invention;

Figures 8 and 9 illustrate another method or arrangement of mounting an orifice construction in a nozzle base or wall 38d. The nozzle 90' is of elongated character, as shown in Figure 8, and is of the cross-sectional configuration shown in Figure 9. The nozzle construction 90 is formed with parallel wall portions 92' spaced vertically to form an orifice or outlet 93, the rear zones of the wall' portions 92 being formed with transversely extending ridges or projections 94 of the form shown in Figure 9. In lieu of the slotted configuration for accommorfating the other types of nozzle construction heretofore described, the wall 38d is formed with a rectangular slot having upper and lower parallel walls 96 and 97- as shown in broken lines in Figure 9. In assembling the nozzle 90 in the rectangular slot in the wall 38d, the nozzle is inserted from the front of the nozzle base to occupy the position shown in Figure 9. A quantity of ceramic or refractory cement 99 is inserted in. the slot in member 38d and in engagement with the projections 94. It is preferableto utilize a cement which will adhere to or be fused with the nozzle base 38d and which will not adhere to the material of which the nozzle 90- is constructed. In this manner the nozzle 90 is fixedly held against dislodgment relative to the nozzle base 38d, but as it is not bonded or fused to the cement 99, it is capable of limited freedom of movement to accommodate expansion' and contraction without affecting the nozzle base 38d. The nozzle construction 90 may be fabricated of the materials hereinbefore mentioned.

Figure 10 shows a nozzle base member 382 which may be fashioned or formed of high-temperature refractory material and coated interiorly with a metal oxide or. a mixture of metal oxides, the oxide coating presenting a surface that is highly resistant to wear when subjected to the intensely hot gases projected through the nozzle orifice. The metal oxide coating is illustrated at 102, and oxides usable for the purpose are iron oxide, mangaa nese oxide, calcium oxide, chromium oxide, nickel oxide, titanium dioxide and tin oxide. In instances where one oxide is applied to another oxide, they may be fused together by subjecting the oxides to high temperatures. For example, the oxide coating may be applied in powderedform and the temperature raised sufiiciently to fuse the oxide to the nozzle member. Furthermore, a mixture of various oxides may be used as a coating composition for the orifice construction. It is to be understood that the orifice walls of the nozzle constructions shown in Figures 1 through 9 may be coated with one or a mixture of the above-mentioned oxides to present wear-resistant surfaces.

Burners of the character shown in Figure 1, when used for attenuation of glass fibers, are capable of delivering high velocity blasts of burned gases of 3000 F. or more. Therefore, the materials of the surfaces of the nozzle construction or the coating of the surfaces must have fusing points well above the temperatures of the burned gases passing through the orifices. The fusing temperatures of the several oxides mentioned herein are well above 3000 F. and, therefore, the oxides are well adapted as surfaces or surface coatings for the nozzle constructions.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

1. An internal combustion burner of the character disclosed having a walled combustion chamber arranged to receive a fuel and air mixture adapted to be burned within the chamber, a front wall of said combustion chamber being formed with an elongated slot extending transversely of the chamber, providing an elongated passage in the chamber wall, the cross-sectional configuration of the slot including recesses extending full length of the slot, an elongated nozzle member arranged to be slidably received endwise in the elongated slot and having flange portions extending into said recesses, said nozzle member being formed with an elongated restricted orifice in registration with the passage in the chamber wall through which the products of combustion from the chamber are discharged as a high velocity blast, said nozzle member being arranged for unrestrained movement in the direction of its length independently of the chamber wall to accommodate expansion under high temperatures of the gases.

2. An internal combustion burner of the character disclosed having a walled combustion chamber arranged to receive a fuel and air mixture adapted to be burned within the chamber, a front wall of said combustion chamber being formed with an elongated slot extending transversely of the chamber providing a substantially rectangular passage in the chamber wall, the cross-sectional configuration of the slot including a recess extending full length of the slot, an elongated nozzle member arranged to be slidably received endwise in the elongated slot, said nozzle member being of a cross-sectional con figuration to snugly fit in the slot and recess, said nozzle member being formed with an elongated restricted passage in registration with the passage in said chamber wall through which the products of combustion from the chamber are discharged as a high velocity blast.

3. An internal combustion burner of the character disclosed having a walled combustion chamber arranged to receive a fuel and air mixture adapted to be burned within the chamber, a wall of said combustion chamber being formed with an elongated slot extending transversely of the chamber, and forming a substantially rectangular passage in the chamber wall, a recess formed in a lengthwise wall surface defining a side of the slot and extending beyond the ends of the passage, an elongated nozzle member arranged to be slidably received endwise in the elongated slot, said nozzle member having an elongated restricted orifice forming a continuation of the passage in the chamber wall through which the products of combustion from the chamber are discharged as a high velocity blast, and a projection formed on the nozzle member extending into said recess.

4. An internal combustion burner of the character dis closed having a walled combustion chamber arranged to receive a fuel and air mixture adapted to be burned within the chamber, said chamber wall structure including a nozzle base formed with an elongated slot extending transversely of the chamber providing a substantially rectangular passage in the nozzle base, the cross-sectional configuration of the slot including recesses extending full length of the slot, an elongated nozzle member arranged to be slidably received endwise in the elongated slot, said nozzle having flange portions extending into said recesses, the nozzle member being formed with an elongated restricted passage in registration with the passage in the nozzle base through which the products'of combustion from the chamber are discharged as a high velocity blast.

5. A combustion burner construction including, in combination, a combustion chamber having a front wall formed with a substantially rectangular restricted passage elongated in a direction transversely of the combustion chamber, the chamber wall portion adjacent the passage being formed with an elongated open-ended slot extending lengthwise of the passage, a nozzle member elon gated lengthwise of the passage arranged to be slidably received endwise in the slot in the chamber wall and f a length extending beyond the ends of the passage, said nozzle member being formed with a substantially rectangular orifice in registration with the rectangular passage formed in the chamber wall, the cross-sectional configuration of the slot and nozzle member being shaped to provide interengaging portions to maintain registration of the orifice in the nozzle member with the passage in the chamber wall, said nozzle member being formed of material containing molybdenum silicide and a metal oxide.

6. A combustion burner construction including, in combination, an elongated combustion chamber arranged to burn a fuel and air mixture, said chamber having a wall formed with an elongated slot arranged transversely of the longitudinal axis of the chamber, the cross-sectional configuration of the slot including a lateral recess formed in each slot-defining wall portion extending lengthwise of the slot, said slot and recesses having open ends, an elongated nozzle member of a cross section reciprocal to that of the slot and recesses arranged to be slidably received in the slot and recesses, said nozzle member having a rectangularly shaped passage, through which hot gases from the chamber are discharged as a high velocity blast, the lengthwise walls defining the passage being substantially parallel with the lengthwise walls of the slot and recesses.

References Cited in the file of this patent UNITED STATES PATENTS 2,554,486 Austin May 29, 1951 2,561,200 Hess July 17, 1951 2,578,101 Stalego Dec. 11, 1951 2,614,619 Fuller Oct. 21, 1952 2,652,890 Morck et al. Sept. 22, 1953 2,681,696 Stalego June 22, 1954

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