FIELD
[0001] The invention relates generally to the field of submerged combustion melting. More specifically, the invention relates to a burner for use in submerged combustion melting.
BACKGROUND
[0002] In submerged combustion melting, a burner is used to inject a flame into a pool of molten material. The flame diffuses upwardly through the molten pool, carrying with it thermal energy for intimate heating of the molten pool. In some cases, the molten pool can begin to freeze at the point where the flame is injected into the molten pool. The freeze can extend upwardly toward the top surface of the molten pool, forming what is known as a "cold finger." Once a cold finger forms in the molten pool, it is normally not reversible and often requires that the melting process be restarted.
[0003] US 6,951,454 B2 discloses a burner according to the preamble of claim 1.
SUMMARY
[0004] In one aspect, the invention relates to a burner apparatus according to claim 1.
[0005] In another aspect, the invention relates to a submerged combustion melting apparatus according to claim 10.
[0006] Other features and advantages of the invention will be apparent from the following description and the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0007] The accompanying drawings, described below, illustrate typical embodiments of the invention and are not to be considered limiting of the scope of the invention, for the invention may admit to other equally effective embodiments. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.
FIG. 1 depicts a vertical cross-section of a burner apparatus.
FIG. 2 depicts a vertical cross-section of a second example of a burner apparatus.
FIG. 3 depicts an enlarged, vertical cross-section of a nozzle included in the burner apparatus of FIGS. 1 and 2.
FIG. 4A depicts a vertical cross-section of a second example of a nozzle.
FIG. 4B depicts a vertical cross-section of a third example of a nozzle.
FIG. 5 depicts a top view of the burner apparatus of FIGS. 1 and 2.
FIG. 6 depicts the inner tube of the burner apparatus of FIGS. 1 and 2 with centralizers.
FIG. 7 depicts a submerged combustion melting system including the burner apparatus of FIG. 1 or 2.
DETAILED DESCRIPTION
[0008] The invention will now be described in detail with reference to a few embodiments, as illustrated in the accompanying drawings. In describing the embodiments, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the invention may be practiced without some or all of these specific details. In other instances, well-known features and/or process steps have not been described in detail so as not to unnecessarily obscure the invention. In addition, like or identical reference numerals are used to identify common or similar elements.
[0009] FIGS. 1 and
2 depict a burner apparatus
100 including an inner tube
102 and an outer tube
104. The inner tube
102 and outer tube
104 may be made of a heat-resistant material, such as a stainless steel, e.g. 304, 312, or other high temperature stainless steel, austenitic nickel-chromium-iron alloys, e.g. Inconel®. The outer tube
104 has a longitudinal bore
106 inside which the inner tube
102 is disposed. The inner tube
102 also has a longitudinal bore
108. Typically, the longitudinal axis of the bore 106 is coincident with the longitudinal axis of the bore
108, i.e., the outer tube
104 and inner tube
102 are coaxial or concentric. The outer diameter of the inner tube
102 is smaller than the inner diameter of the bore
106, resulting in an annular space
110 between the outer tube
104 and the inner tube
102. Gases, e.g., fuel and oxidant, can be supplied to the annular space
110 and the bore
108 during operation of the burner apparatus
100. Typically, the gas in the bore
108 will be different from the gas in the annular space
110. For example, natural gas could be flowed in the bore
108 while oxygen is flowed in the annular space
110, or vice versa. The tip
113 of the inner tube
102 includes a nozzle
126. In the example shown in
FIG. 1, the nozzle
126 is recessed relative to the top surface
115 of the burner apparatus
100. The space
112 above the nozzle
126 defines a combustion chamber
112 in which the gases from the bore
108 and annular space
110 combine and undergo combustion. In the example shown in
FIG. 2, the nozzle
126 is flush or substantially flush with the top surface
115 of the burner apparatus
100. Thus, convergence and combustion of the gases in the bore
108 and annular space
110 take place outside of the burner apparatus
100. Returning to
FIG. 1, the corners of the wall
127 defining the combustion chamber
112 could be hard corners as illustrated, but more often would be filleted or radiused.
[0010] Referring to
FIGS. 1 and
2, the inner tube
102 has a closed bottom end
114, which seals the bottom of the bore
108 in these embodiments. Near the bottom end
114, the inner tube
102 includes a port
116, which is in communication with the bore
108. An external source of gas (not shown), e.g., a source of fuel, can be connected to the port
116 in order to supply gas to the bore
108. In other embodiments, the closed bottom end
114 could include a port for introduction of gas into the bore
108. The outer tube
104 has a partially closed bottom end
118 with an opening
120 for receiving the inner tube
102. The bottom end
118 seals the bottom of the annular space
110 by extending between the outer tube
104 and the inner tube
102. In the examples shown in
FIGS. 1 and
2, a bottom portion
122 of the inner tube
102 including the port
116 extends below the bottom end
118 of the outer tube
104. The inner tube
102 may be capable of sliding relative to the opening
120 so that adjustment of the position of the inner tube
102 relative to that of the outer tube
104 is possible, e.g., in order to control the size of the combustion chamber
112. Near the bottom end
118, the outer tube
104 includes a port
124, which is in communication with the annular space
110. An external source of gas (not shown), e.g., a source of oxidant, can be connected to the port
124 in order to supply gas to the annular space
110. Alternatively, the bottom end
118 may include a port for introduction of gas into the bore 108.
[0011] Referring to
FIG. 3, the nozzle
126 (formed at the tip of the inner tube
102 in
FIGS. 1 and
2) includes a nozzle body
128 having a central hole
130 and side holes
132. The holes
132 are called "side" holes because they are offset from the center of the nozzle body
128. The side holes
132 are provided in the nozzle body
128 for gas flow. In one embodiment, the central hole
130 is also provided in the nozzle body
128 for gas flow. In other embodiments, the central hole
130 may be absent or plugged (as illustrated in
FIG. 4B), leaving only the side holes
132 open for gas flow. When the central hole
130 is present in the nozzle body
128, it may serve as an opening for gas flow or as a receptacle or passage for instruments such as a UV safety sensor. Referring to
FIG. 5, the side holes
132 are distributed around the center
129 of the nozzle body
128. In the illustrated embodiment, the side holes
132 are generally equidistant from the center
129 of the nozzle body
128. In other embodiments, the side holes
132 may not be equidistant from the center
129 of the nozzle body
128 (see, for example,
FIG. 4B, where the line
Z indicates the center of the nozzle body
128)
. In
FIGS. 3, 4A, and
4B, the side holes
132 are slanted relative to the vertical (or longitudinal axis of the nozzle
126),
Z. The longitudinal axis of the nozzle
126 is in a direction running from the inlet face
134 of the nozzle body
128 to the outlet face
136 of the nozzle body
128 and is located generally in the center of the nozzle
126. In one embodiment, the angle
α between the each of the side holes
132 and the vertical,
Z, may be in a range from about 25° to 65°. In another embodiment, the angle α between the each of the side holes
132 and the vertical,
Z, may be in a range from about 30° to 60°. In yet another embodiment, the angle α between the each of the side holes
132 and the vertical,
Z, may be in a range from about 45° to 50°. In the embodiment illustrated in
FIG. 4A, the angle α between each of the side holes
132 and the vertical,
Z, is 45° or approximately 45°. The side holes
132 may be slanted at the same or different angles relative to the vertical,
Z.
[0012] The inlet face
134 of the nozzle body
128 faces the bore
108, while the outlet face
136 of the nozzle body
128 faces the exterior of the inner tube
102. In
FIGS. 3 and
4A, the central hole
130 extends from the inlet face
134 to the outlet face
136 of the nozzle body
128 and communicates with the bore
108. In
FIGS. 3, 4A, and
4B, the side holes
132 extend from the inlet face
134 to the outlet face
136 and also communicate with the bore
108 at the inlet face
134. At the outlet face
136 of the nozzle body
128, the side holes
132 and central hole
130 may have any desired shape, such as circular, square, rectangular, or oval. In one embodiment, as illustrated more clearly in
FIG. 5, the side holes
132 terminate at the outlet face
136 with an elongated shape, e.g., oval, in order to reduce or eliminate overheating of the outlet face
136. Referring to
FIGS. 3, 4A, and
4B, where the side holes
132 are circular in cross-section (or have any other non-elongated cross-section, e.g., square), the elongated shape at the outlet face
136 may be achieved by making the portion
135 of the outlet face
136 including the side holes
132 oblique (i.e., not parallel or perpendicular) to the longitudinal axis,
L, of the side holes
132. In one example, the portion
135 can be made horizontal or substantially horizontal relative to the vertical (or longitudinal axis of the nozzle
126)
, Z, to achieve the elongated shape of the side holes
132 at the outlet face
136.
[0013] Returning to
FIGS. 1 and
2, the cross-sectional flow area of the annular space
110 and the cross-sectional flow area of the nozzle
126 should be selected such that the pressure in the annular space
110 and the pressure in the bore
108 are equalized or substantially equalized. For example, when the inner tube
102 carries natural gas and the annular space
110 carries oxygen, the cross-sectional flow area of the annular space
110 can be approximately twice the cross-sectional area of the nozzle
126 to allow the aforementioned equalization of pressure. The cross-sectional flow area of the nozzle
126 is determined by the combined cross-sectional flow areas of the side holes
132 and the cross-sectional flow area of the central hole
130, if present and used as an opening for gas flow.
[0014] The side holes
132 serve the purpose of laterally broadening the flow coming out of the nozzle
126. At the outlet face
136 of the nozzle
126, the broadened flow combines with the flow from the annular space
110, resulting in a broadened flame. The flame produced by the burner apparatus
100 can be made even broader by providing protuberances
138 on the exterior of the nozzle
126. The protuberances
138 spread the flow at the exterior of the nozzle
126. The protuberances
138 may be formed on or otherwise attached to the nozzle
126. In one example, as shown more clearly in
FIG. 5, the corners of a polygonal flange
140 mounted on the nozzle
126 function as the protuberances
138. The corners
138 may be sharp or rounded. Returning to
FIGS. 1 and
2, the protuberances
138 may be flush or substantially flush with the outer edge of the outlet face
136 of the nozzle
126 so that the flow spreading provided by the protuberances is near enough to the outlet face
136 of the nozzle
126 to have an effect on the quality of the flame produced by the burner apparatus
100. The nozzle
126, as described above, allows a short, broad flame to be produced by the burner apparatus
100. This short, broad flame can help eliminate or reduce the occurrence of a cold finger when the burner apparatus
100 is used in submerged combustion melting. It is important not to spread the flame of the burner too much so that a low pressure area does not form at the center of the flame. The spreading of the flame is determined at least in part by the size and angle of the side holes
132, the size of the central hole
130 if present, and the size and positioning of the protuberances if present.
[0015] Returning to
FIGS. 1 and
2, to provide and maintain a symmetric flame, the inner tube
102 is preferably centered within the longitudinal bore
106 of the outer tube
104. This may be achieved through the use of one or more centralizers
142 which may be coupled to the exterior of the inner tube
102. Preferably, the centralizers
142 are relatively rigid to ensure that the inner tube
102 remains fixed in position relative to the outer tube
104 during operation of the burner apparatus. In one example, as illustrated in
FIG. 6, each centralizer
142 may include a tapered slot
144 formed on the inner tube
102 and an adjustable wedge
146 arranged in the tapered slot
144. As more clearly shown in
FIG. 5, the centralizers
142 are distributed around the circumference of the inner tube
102 to provide the desired centralizing function. Returning to
FIGS. 1 and
2, the adjustable wedges
146 extend laterally and outwardly from the inner tube
102 to the inner diameter of the outer tube
104. In addition to centralizing the inner tube
102 within the bore
106, the adjustable wedges
146 may be used to establish and adjust the longitudinal position of the inner tube
102 relative to the outer tube
104. Such adjustments may be used to control the size of the combustion chamber
112. Other types of centralizers known in the art for centralizing a tubular member within another tubular member may be used.
[0016] A cooling jacket
150 surrounds the outer tube
104, which in turn surrounds the inner tube
102. The cooling jacket
150 may be mounted on the outer tube
104. The cooling jacket
150 includes a pocket
152 so that when it is mounted on, or otherwise positioned adjacent to, the outer tube
104, an annular space
154 is defined between the cooling jacket
150 and the outer tube
104. The annular space
154 serves as a conduit through which cooling gas can be circulated around the outer tube
104 and during operation of the burner apparatus
100. The cooling jacket
150 includes an inlet port
156 and an outer port
158, both of which are in communication with the annular space
154. The cooling jacket
150 may include an annular partition
155 disposed in the annular space
154 to create an inlet flow path
160 and an outlet flow path
162 within the annular space
154. The inlet flow path
160 is in communication with the inlet port
156, while the outlet flow path
162 is in communication with the outlet port
158. The partition
155 may be disposed in the annular space
154 such that gas in the inlet flow path
160 can flow into the outlet flow path
162. In this arrangement, cooling gas enters the cooling jacket
150 through the inlet port
156, flows through the inlet flow path
160 into the outlet flow path
162, flows through the outlet flow path
162 to the outlet port
158, and then out of the cooling jacket
150. In one example, both the inlet flow path
160 and outlet flow path
162 surround the outer tube
104, with the inlet flow path
160 being closer to the outer tube
104.
[0017] Referring to
FIGS. 1 and
2, oxidant
164 is supplied to the annular space
110 through the port
124, and fuel
166 is supplied to the bore
108 through the port
116. The fuel exits the inner tube
102 through the nozzle
126 and mixes with the oxidant in the annular space
110 to form a flame (not shown). As the burner apparatus
100 operates, cooling gas
168 is supplied to the cooling jacket
150 through the port
156, and warmer cooling gas
170 is removed from the cooling jacket
150 through the port
158. In submerged combustion melting, the flame of the burner apparatus
100 is injected into a molten pool. If the burner apparatus
100 shown in
FIG. 1 is used, the flame is formed within the burner and then injected into the molten pool. If the burner apparatus
100 shown in
FIG. 2 is used, the flame is formed outside of the burner. In this case, the burner apparatus may be positioned such that the flame is formed within the molten pool. As noted above, the short broad flame produced by the burner apparatus can help reduce or eliminate freezing at the point where the flame is injected into the molten pool. This can ultimately help avoid formation of cold finger in the molten pool.
[0018] FIG. 7 shows a submerged combustion melting apparatus
171 including a melting chamber
172 containing a molten pool
174. The melting chamber
172 includes a port
176 for feeding batch material from a hopper
175 into the melting chamber
172. The batch material may be provided in liquefied form. The melting chamber
172 also includes a port
168 through which exhaust gases can escape the melting chamber
172. The melting apparatus
171 also includes a conditioning chamber
180 connected to the melting chamber
172 by a flow passage
182. Molten material from the molten pool
164 flows from the melting chamber
172 to the conditioning chamber
180 through the flow passage
182 and then exits the melting apparatus
171. Orifices
186 are formed in the wall of the melting chamber
162. The orifices
176 are shown in the bottom wall
188 of the melting chamber
172. In alternate arrangements, the orifices
176 may be provided in the side wall
190 of the melting chamber
172. The orifices
186 may be perpendicular or slanted relative to the wall of the melting chamber
172. Burner apparatus
100 are arranged in the orifices
186 to inject flames into the molten pool
174.
[0019] The burner apparatus
100 may help prevent freezing at the point where the flames are injected into the molten pool
174 and ultimately avoid formation of cold finger in the molten pool
174. Cold finger is caused by a combination of the depth of the molten pool above the burner head and the velocity of the gases at the burner head. If the flame from the burner head cannot travel fast enough to burn in this area (i.e., above the burner head), there will be no heat in this area. As a result, this area is being cooled by the gases flowing through it and freezes into a tube shape. When the frozen melt is cracked open, the tube often looks like a finger, hence the term "cold finger." With the burner apparatus
100, the side holes (
132 in
FIG. 1) divert some of the gas from the inner tube (
102 in
FIG. 1) from the laminar flow regime. This helps push the combustion chamber (i.e., where the flame is formed) open. The protuberances (
138 in
FIG. 1) outside the inner tube deflects some of the gas from the outer tube. This also helps push the combustion chamber open and slows down the gas velocity in the combustion chamber. Both features promote mixing of the gases, creating more combustion sooner.
1. Brennervorrichtung (100), die umfasst:
ein Außenrohr (104) mit einer ersten Längsbohrung (106);
ein Innenrohr (102) mit einer zweiten Längsbohrung (108), wobei das Innenrohr (102) in der ersten Längsbohrung (106) angeordnet ist, sodass ein ringförmiger Raum zwischen dem Innenrohr und dem Außenrohr definiert wird;
eine an einer Spitze des Innenrohrs ausgebildete Düse (126), wobei die Düse eine Einlassseite aufweist, die der zweiten Längsbohrung (108) zugewandt ist, und eine Austrittsseite in gegenüberliegender Beziehung zur Einlassseite, wobei die Düse (126) eine Vielzahl von darin ausgebildeten Seitenbohrungen (132) umfasst, wobei sich die Seitenbohrungen (132) von der Einlassseite (234) zur Austrittsseite (136) erstrecken, wobei die Seitenbohrungen (132) in Bezug auf eine Längsachse (Z) der Düse (126) nach außen geneigt sind und in Verbindung mit der zweiten Längsbohrung (108) stehen, dadurch gekennzeichnet, dass;
sie eine Vielzahl von Vorsprüngen (138) umfasst, die seitlich von einer Außenseite der Düse (126) hervorstehen, wobei jeder der Vorsprünge (138) seitlich in seiner Position einer der Seitenbohrungen (132) entspricht, wobei die Vielzahl von Vorsprüngen (138) durch Ecken eines mehreckigen Flanschs (140) bereitgestellt sind, der an der Außenseite der Düse (126) befestigt ist, wobei die Ecken des mehreckigen Flanschs (140) in Bezug auf eine Mitte (129) des mehreckigen Flanschs (140) radial ausgerichtet sind.
2. Brennervorrichtung (100) nach Anspruch 1, wobei jede der Seitenbohrungen (132) mit einem Winkel in einem Bereich von 25° bis 65° in Bezug auf eine Längsachse der Düse nach außen geneigt ist.
3. Brennervorrichtung (100) nach Anspruch 1, wobei die Düse ferner eine darin ausgebildete mittlere Bohrung (130) umfasst, wobei die mittlere Bohrung in Verbindung mit der zweiten Längsbohrung (108) steht.
4. Brennervorrichtung (100) nach Anspruch 1, wobei die Seitenbohrungen um die Mitte der Düse verteilt sind.
5. Brennervorrichtung (100) nach Anspruch 1, wobei die Düse (126) im Wesentlichen mit einer Endfläche der Brennervorrichtung bündig abschließt.
6. Brennervorrichtung (100) nach Anspruch 1, wobei die Düse in Bezug auf eine Endfläche der Brennervorrichtung versenkt ist.
7. Brennervorrichtung (100) nach Anspruch 1, wobei die Seitenbohrungen (132) an einer Austrittsseite der Düse mit einer länglichen Form enden.
8. Brennervorrichtung (100) nach Anspruch 1, wobei eine Strömungsquerschnittsfläche des ringförmigen Raums und eine Strömungsquerschnittsfläche der Düse so ausgewählt sind, dass ein Druck im ringförmigen Raum im Wesentlichen gleich einem Druck in der zweiten Längsbohrung (108) ist.
9. Brennervorrichtung (100) nach Anspruch 1, die ferner auf der Düse ausgebildete Vorsprünge umfasst, wobei die Vorsprünge seitlich in ihrer Position den ersten Bohrungen entsprechen.
10. Tauchbrennschmelzvorrichtung (171), die umfasst:
eine Schmelzkammer (172) zum Aufnehmen eines Schmelzbads (174), wobei die Schmelzkammer eine in einer Wand davon ausgebildete Öffnung (186) aufweist;
und einen Brenner (100) nach Anspruch 1, der an der Öffnung positioniert ist, um eine Flamme in die Schmelzkammer (172) einzuspeisen.