Inlet assembly for an abatement device - Patents.com

Abstract

An inlet assembly and method for an abatement apparatus is disclosed. The inlet assembly is for use in an abatement apparatus and includes an inlet nozzle defining a non-circular inlet opening coupleable to an inlet conduit supplying an exhaust gas stream for treatment in the abatement apparatus, at least one outlet opening, and a nozzle bore extending along a longitudinal axis between the non-circular inlet opening and the outlet opening for conveying the exhaust gas stream from the non-circular inlet opening to the outlet opening for delivery to a treatment chamber of the abatement apparatus. The nozzle bore defines an inlet section extending from the non-circular inlet opening, a flow dividing structure disposed downstream of the inlet section and configured to separate the exhaust gas stream into at least a pair of exhaust gas streams, and an outlet section extending to the outlet opening and configured to convey the pair of exhaust gas streams to the treatment chamber of the abatement apparatus. In this manner, multiple exhaust gas streams can be generated or produced by the inlet assembly, which helps improve the performance of the abatement apparatus, especially at low flow rates.

Description

[Technical field]

[0001] The present invention relates to an inlet assembly for an abatement system and method thereof. [Background technology]

[0002] Abatement devices, such as plasma abatement devices, electrical abatement devices, and radiant burners, are known and are typically used to treat exhaust gas streams from manufacturing process tools used, for example, in the semiconductor or flat panel display manufacturing industries. During such manufacturing, residual perfluorinated compounds (PFCs) and other compounds are present in the exhaust gas streams exiting the process tools. PFCs are difficult to remove from the exhaust gases and, furthermore, are known to have a relatively high greenhouse effect, making them undesirable to release into the environment.

[0003] Known radiant burners use combustion to remove PFCs and other compounds from an exhaust gas stream. Typically, the exhaust gas stream is a nitrogen stream containing PFCs and other compounds. A fuel gas is mixed with the exhaust gas stream, and the gas stream mixture is conveyed to a combustion chamber bounded laterally by the exit face of a perforated gas burner. Fuel gas and air are simultaneously fed to the perforated burner to affect flameless combustion at the exit face, and the amount of air passing through the perforated burner is sufficient to consume not only the fuel gas fed to the burner, but also all combustibles in the gas stream mixture injected into the combustion chamber. Similar techniques are utilized in plasma and electrical abatement devices.

[0004] Because the range of compounds present in the exhaust gas stream and the flow characteristics of that exhaust gas stream can vary from process tool to process tool, the range of fuel gases and air, as well as other gases or fluids that need to be introduced into the radiant burner, can also vary. Summary of the Invention [Problem to be solved by the invention]

[0005] Although techniques exist for treating exhaust gas streams, each has its own drawbacks. It would therefore be desirable to provide improved techniques for treating exhaust gas streams. [Means for solving the problem]

[0006] According to a first aspect, an inlet assembly for an abatement apparatus is provided, the inlet assembly comprising an inlet nozzle defining a non-circular inlet opening connectable to an inlet conduit supplying an exhaust gas flow for treatment in the abatement apparatus, at least one outlet opening, and a nozzle bore extending along a longitudinal axis between the non-circular inlet opening and the outlet opening for conveying the exhaust gas flow from the non-circular inlet opening to the outlet opening for supplying to a treatment chamber of the abatement apparatus, the nozzle bore defining an inlet section extending from the non-circular inlet opening, a flow dividing structure positioned downstream of the inlet section and configured to separate the exhaust gas flow into at least a pair of exhaust gas flows, and an outlet section extending to the outlet opening and configured to convey the pair of exhaust gas flows to the treatment chamber of the abatement apparatus.

[0007] The first aspect recognizes that the shape and configuration of the inlet nozzle of the inlet assembly of the abatement device can have a significant impact on the performance of the abatement device. Existing nozzles can have a passable performance, especially at high flow rates, but their performance can be degraded, especially at low flow rates. Accordingly, an inlet assembly of an abatement device is provided. The inlet assembly can include an inlet nozzle or conduit. The inlet nozzle can have other than an inlet opening that can be coupled with a conduit or hose that supplies the exhaust gas stream to be treated by the abatement device. The inlet can also have one or more outlet openings that can supply the exhaust stream to the treatment chamber of the abatement device. The inlet nozzle can include one or more nozzle bores that extend along the length of the inlet nozzle from the inlet opening to the one or more outlet openings. The nozzle bore can have an inlet section or region that extends from or adjacent to the inlet opening. The nozzle bore can have a flow splitting structure, a separated flow structure, or a weir structure located downstream or adjacent to the inlet section. The separated flow structure can separate, distribute, or split the exhaust gas stream into two or more exhaust gas streams. The nozzle bore may also have an outlet portion extending between the flow dividing structure and the outlet opening, which conveys the exhaust stream to the outlet opening for treatment of the exhaust stream in the treatment chamber of the abatement device. In this manner, multiple exhaust streams are generated or produced by the inlet assembly, which helps to improve the performance of the abatement device, especially at low flow rates. This is because exhaust treatment mechanisms generally rely on diffusion processes in the radiant burner, and combustion bi-products must diffuse into the exhaust stream in order to perform the abatement reaction. In other words, the combustion bi-products must diffuse widely from the outer surface of the exhaust stream into the exhaust stream before reacting with the exhaust stream before it leaves the radiant burner. Failure to completely diffuse into the exhaust stream reduces the abatement efficiency. By generating multiple separate exhaust streams from the exhaust stream entering the nozzle, the distance along which the diffusion reaction must occur is reduced compared to a comparable single exhaust stream. Similarly, multiple exhaust streams can be generated by the inlet nozzle, even at low flow rates.

[0008] In one embodiment, the flow splitting structure is configured to split the exhaust gas flow into a pair of exhaust gas streams that flow on either side of the flow splitting structure. The flow splitting structure can thus generate exhaust gas streams through the presence of the flow splitting structure. The presence of the flow splitting structure separates the exhaust gas streams to reduce remixing and minimize the size of each exhaust gas stream.

[0009] In one embodiment, the flow splitting structure is located in the center of the nozzle bore. The central location of the flow splitting structure can help provide asymmetric uniform flow to the process chamber and maximize separation of the exhaust gas streams.

[0010] In one embodiment, the flow splitting structure is configured to separate the exhaust gas stream into a pair of exhaust gas streams that flow close to a surface of the nozzle bore. Creating the exhaust gas streams close to a surface of the nozzle bore also aids in separating the exhaust gas streams.

[0011] In one embodiment, the inlet nozzle defines a single nozzle bore extending from the non-circular inlet opening to the outlet opening with the flow diverter structure disposed therein. Thus, the inlet nozzle may comprise a single, sole or unified nozzle bore that houses the flow diverter structure.

[0012] In one embodiment, the flow splitter structure is configured to split the nozzle bore into a pair of nozzle bores. The flow splitter structure may thus separate the nozzle bore into two or more downstream nozzle bores.

[0013] In one embodiment, the inlet nozzle defines a single nozzle bore extending from the non-circular inlet opening to the flow diverter structure, and a pair of nozzle bores extending from the flow diverter structure to a pair of outlet openings. Thus, an inlet nozzle may have a single bore at its inlet that extends to the flow diverter structure, but then may have a pair of nozzle bores that extend from the flow diverter structure to a corresponding two or more outlet openings.

[0014] In one embodiment, the inlet nozzle defines a lofted transition from the single nozzle bore to the pair of nozzle bores via a flow dividing structure, thus providing a smooth transition between the single nozzle bore and the pair of nozzle bores.

[0015] In one embodiment, the inlet nozzle has a longitudinal length extending in a primary direction of flow of the exhaust stream, and the flow diverting structure reduces the cross-sectional area of ​​the nozzle bore along the longitudinal axis. Thus, the presence of the flow diverting structure can result in a reduction, narrowing or restriction of the cross-sectional area of ​​the nozzle, thereby increasing the flow of the exhaust stream.

[0016] In one embodiment, the flow diverting structures are positioned no closer to the non-circular inlet opening than about 20% of its longitudinal length.

[0017] In one embodiment, the flow diverting structure is shaped to present a surface oriented with a transverse component relative to the longitudinal axis, and thus the flow diverting structure may have a portion that extends across a portion of the width of the nozzle bore.

[0018] In one embodiment, the surfaces are oriented at about 20° to 70° relative to the longitudinal axis. Thus, the surfaces can be oriented to achieve the desired flow characteristics of the exhaust stream.

[0019] In one embodiment, the surface is at least one of planar and curved, so that the surface can be shaped to achieve the required flow characteristics of the exhaust stream.

[0020] In one embodiment, the flow diverter structure is shaped to present a pair of surfaces that are mirror images about the longitudinal axis and at least one of the major and minor axes of the nozzle bore extending transversely to the longitudinal axis, and thus the flow diverter structure may be symmetric about the central axis of the inlet nozzle.

[0021] In one embodiment, the non-circular inlet opening is an elongated and / or generally quadrilateral slot and / or an ellipse.

[0022] In one embodiment, the inlet assembly includes a baffle disposed upstream of the flow dividing structure, the baffle defining a baffle opening, the baffle opening having a reduced cross-sectional area compared to a cross-sectional area of ​​the nozzle bore adjacent the baffle.

[0023] According to a second aspect, a method is provided comprising the steps of: receiving an exhaust flow at an inlet assembly for an abatement apparatus, the inlet assembly comprising an inlet nozzle defining a non-circular inlet opening connectable to an inlet conduit supplying an exhaust gas flow for treatment by the abatement apparatus, at least one outlet opening, and an inlet nozzle defining a nozzle bore extending along a longitudinal axis between the non-circular inlet opening and the outlet opening, the nozzle bore defining an inlet section extending from the non-circular inlet opening, a diversion structure disposed downstream of the inlet section, and an outlet section extending to the outlet opening; conveying the exhaust gas flow from the non-circular inlet opening to the diversion structure; separating the exhaust gas flow into at least a pair of exhaust gas flows using the diversion structure; and conveying the pair of exhaust gas flows to at least one outlet opening for delivery to a treatment chamber of the abatement apparatus.

[0024] In embodiments of the second aspect, corresponding features to the embodiments of the first aspect are provided.

[0025] Further particular and preferred aspects are set out in the dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate and in other combinations than as explicitly set out in the claims.

[0026] Where features of an apparatus are described as operable to provide a certain functionality, this should be understood to include features of an apparatus that provide that functionality, or that are adapted or configured to provide that functionality. Embodiments of the present invention will be further described with reference to the accompanying drawings. [Brief description of the drawings]

[0027] [Figure 1]1 illustrates a head assembly according to one embodiment coupled with a radiant burner assembly. [Diagram 2] 1 illustrates a head assembly according to one embodiment coupled with a radiant burner assembly. [Diagram 3] FIG. 2 illustrates a cross-sectional view through an inlet nozzle according to one embodiment. [Figure 4] FIG. 2 illustrates a cross-sectional view through an inlet nozzle according to one embodiment. [Figure 5A] 1 illustrates an inlet nozzle according to one embodiment. [Figure 5B] 1 illustrates an inlet nozzle according to one embodiment. [Figure 6] 1 shows a baffle plate positioned upstream of the inlet nozzle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Before describing the embodiments in more detail, an overview will first be presented. The embodiments provide a burner inlet assembly. The burner inlet assembly includes a flow splitter structure or weir that splits a received exhaust gas stream into multiple separate exhaust gas streams for delivery to the treatment chamber of the abatement device. The presence of the flow splitter helps to maintain separate exhaust streams, even at low flow rates. This reduces the distance along which diffusion reactions need to occur compared to the distance of an equivalent single exhaust gas stream, which improves abatement performance, especially at low flow rates.

[0029] Although the following embodiment describes the use of radiant burners, it should be understood that the inlet assembly can be used with any of a variety of burners, such as, for example, a turbulent flame burner or an electrically heated oxidizer. Radiant burners are widely known in the art, such as those described in EP 0694735.

[0030] Head Assembly 1 and 2 show a head assembly according to one embodiment coupled to a radiant burner assembly 100 (generally designated 10). In this example, the radiant burner assembly 100 is a concentric burner having an inner burner 130 and an outer burner 110 (although other arrangements are possible). A mixture of fuel and oxidant is supplied to the outer burner 110 via a plenum (not shown) in a plenum housing 120 and supplied to the inner burner 130 via a conduit (not shown).

[0031] The head assembly 10 comprises three main sets of components. First, a metal (usually stainless steel) housing 20, which provides the necessary mechanical strength and structure to mate with the radiant burner assembly 100. Second, insulation 30 provided within the housing 20, which serves to reduce heat loss from within the combustion chamber defined between the inner burner 130 and outer burner 110 of the radiant burner assembly 100, and also to protect the housing 20 and its associated elements from heat generated within the combustion chamber. Third, an inlet assembly 60, which receives a nozzle within space 50 and is received by a series of identical standardized openings 40 (see FIG. 2) provided in the housing 20. This arrangement allows the individual inlet assemblies 60 to be removed for maintenance without the need to completely remove or disassemble the head assembly 10 from the remainder of the radiant burner assembly 100.

[0032] 1 utilizes five identical inlet assemblies 60, each mounted within a corresponding opening 40, with a sixth opening shown unused. It should be understood that not all openings 40 may be blocked with an inlet assembly 60 that receives effluent or process fluid, or other fluid, through its nozzle, but may instead receive a blanking inlet assembly to completely block the opening 40, or may instead receive an inlet assembly containing sensors for measurement to monitor conditions within the radiant burner. It should also be understood that more or less than six openings 40 may be provided, and that they need not be arranged circumferentially around the housing, or that they need not be arranged symmetrically.

[0033] As can be seen in Figures 1 and 2, additional openings are provided in housing 20 to accommodate other elements, such as, for example, sight glass 70 and pilot 75A.

[0034] The inlet assembly 60 includes insulation to protect the structure of the inlet assembly 60 from the combustion chamber. The inlet assembly 60 is held in place using suitable fasteners, such as bolts (not shown), which may be removed to facilitate removal of the fasteners, and is also protected with insulation (not shown). As described in more detail below, the nozzle includes one or more outlet openings and a baffle portion.

[0035] Inlet nozzle - first embodiment FIG. 3 is a cross-sectional view through an inlet nozzle 200A according to an embodiment. The inlet nozzle 200A is a mirror image of the cross-sectional view shown in FIG. 3. The inlet nozzle 200A generally fits into a space 50 shaped to fit its outer surface. The inlet nozzle 200A comprises an inlet opening 210A, an outlet opening 220A, and a nozzle bore 230A extending along a longitudinal axis A between the inlet opening 210A and the outlet opening 220A. In this example, the nozzle bore 230A has an elliptical cross-section. The ellipse comprises two semicircles connected by parallel lines, which are tangents to the end points of the semicircles. The inlet nozzle thus forms a flat tube with parallel main faces and a semi-cylindrical joining surface. The outer wall defining the nozzle bore 230A has a uniform cross-section along the longitudinal axis A.

[0036] A flow diverter 240A is provided within the nozzle bore 230A. The flow diverter 240A extends from and between the two major faces of the nozzle bore 230A. Specifically, the flow diverter 240A presents a curved surface rising from the major faces of the nozzle bore 230A and is shaped to divide the exhaust flow stream traveling generally along the longitudinal axis A and to create two streams that flow near the rounded portion of the nozzle bore 230A. The curved surface of the flow diverter 240A extends from a central location toward the curved portion of the nozzle bore 230A to form an arch-shaped structure shown in cross section in FIG. 3, with the major surface formed as a generally cylindrical recess.

[0037] During operation, a discharge flow is introduced through the inlet opening 210A and travels generally in the direction of the longitudinal axis A. The discharge flow is split into two discharge streams, one passing through either side of the flow divider 240A and exiting the outlet opening 220A generally as a pair of discharge streams.

[0038] Inlet nozzle - second embodiment FIG. 4 is a cross-sectional view through an inlet nozzle 200B according to one embodiment. The inlet nozzle 200B is identical to the inlet nozzle described above, but has a differently shaped flow diverter 240B. The flow diverter 240B extends from and between the two inner major surfaces of the nozzle bore 230B. Specifically, the flow diverter 240B is formed from a pair of flat surfaces rising from the inner major surfaces of the nozzle bore 230B and is shaped to divide the exhaust flow stream traveling generally along the longitudinal axis A and to create two streams that enter near the rounded portion of the nozzle bore 230B. The flat surfaces of the flow diverter 240B extend from a central location toward the curved portion of the nozzle bore 230B, forming an inverted V-shaped structure shown in cross section in FIG. 4, with the major surfaces being formed as a pair of generally flat surfaces.

[0039] During operation, the exhaust flow is introduced through the inlet opening 210B and travels generally in the direction of the longitudinal axis A. The exhaust flow is split into two exhaust streams, one passing through either side of the flow divider 240B and exiting through the outlet opening 220B generally as a pair of exhaust streams.

[0040] Inlet nozzle - third embodiment Figures 5A and 5B show an inlet nozzle 200C according to one embodiment, which is identical to the embodiment of Figure 3, except that the flow diverter 240C extends along the longitudinal axis A to the location of the outlet openings 220C, 220D, and excess portions of the major surface of the nozzle bore 230C are removed. Thus, in this embodiment, the inlet nozzle 200C has one inlet opening 210C and two outlet openings 220C, 220D.

[0041] During operation, a discharge flow is introduced through the inlet opening 210C and travels generally in the direction of the longitudinal axis A. The discharge flow is split into two discharge streams, one of which passes through one side of the flow divider 240C and exits through the two outlet openings 220C, 220D as a pair of discharge streams.

[0042] It should be understood that the position of the flow dividers 240A, 240B, 240C can be varied to suit the flow conditions. If the exhaust flow entering the inlet openings 210, 210A, 210B is not uniform or asymmetric, the position of the flow dividers 240A, 240B, 240C can be adjusted in an axis transverse to the longitudinal axis A to generate a pair of symmetric exhaust gas flows. Also, the position of the flow dividers 240A, 240B, 240C can be varied to vary the distance from the inlet openings 210A, 210B, 210C to avoid any areas of high turbulence. Also, it should be understood that the shape and angle of attack of the pair of surfaces of the flow dividers 240A, 240B, 240C can be varied to suit the flow conditions.

[0043] Baffle plate In an embodiment, as shown in Figure 6, the baffle plate 250 is positioned upstream of the flow splitter structure 240, 240A, 240B. The baffle plate 250 may be located within the nozzle bores 230A, 230B, 230, over the inlet openings 210A, 210B, 210C, or within a coupling 260 that mates with the inlet nozzles 200A, 200B, 200C (as shown).

[0044] It can thus be seen that embodiments provide a segmented slot nozzle, this arrangement improves performance over known nozzles at low flow rates, and in particular, while some known nozzles may provide good abatement performance, particularly at high flow rates, this embodiment extends that performance down to low flow rates.

[0045] Typically, in an embodiment, the nozzle is constructed from a heat and chemically resistant metal alloy, for example ANC16. Conveniently, the nozzle is formed by a casting process, for example lost wax casting. The inlet to the nozzle is in the form of an elliptical opening, 16mm inside width on 50mm centres. Typically, this shape continues in parallel for about 25% of the total length. A weir or flow divider is then formed in the central section, encouraging the flow to take two separate streams. In one embodiment, the weir is such that the nozzle has two separate outlets. These outlets may be circular. They may be on the same centre as the elliptical inlet. In other embodiments, the weir extends a greater or lesser distance towards the discharge end of the nozzle maintaining the same elliptical shape as the inlet. The weir may be chevron shaped, flat faced or rounded.

[0046] Although exemplary embodiments of the present invention are disclosed in detail herein with reference to the accompanying drawings, it should be understood that the present invention is not limited to the detailed embodiments, and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention as defined by the claims and their equivalents. [Explanation of symbols]

[0047] 10 Head Assembly 20. Housing 30 Insulator 40 Opening 50 space 60 Inlet assembly 70 Inspection window 75A Pilot 100 Radiant burner assembly 110 Outer Burner 120 Plenum Housing 130 Inner Burner 200A, B, C Inlet Nozzle 210A, B, C inlet openings 220A, B, C, D External opening 230A, B, C nozzle bore 240A, B, C Flow Dividers 250 Baffle Plate 260 Coupling

Claims

1. 1. An inlet assembly for an abatement apparatus, the inlet assembly comprising: a non-circular inlet opening coupleable to an inlet conduit for providing a flue gas stream for treatment in the abatement device; at least one outlet opening; a nozzle bore extending along a longitudinal axis between the non-circular inlet opening and the outlet opening for conveying the exhaust gas stream from the non-circular inlet opening to the outlet opening for supplying the exhaust gas stream to a treatment chamber of the abatement apparatus; [0023] an inlet nozzle defining The nozzle bore is an inlet portion extending from the non-circular inlet opening; a flow splitting structure disposed downstream of the inlet portion and configured to split the exhaust gas flow into at least a pair of exhaust gas flows; an outlet section extending to the outlet opening and configured to convey the pair of exhaust gas streams to the treatment chamber of the abatement apparatus; stipulates, the inlet nozzle defines the nozzle bore as a single nozzle bore extending from the non-circular inlet opening to the outlet opening and having the flow diverter structure disposed therein; entrance assembly.

2. The inlet assembly of claim 1 , wherein the flow splitting structure is configured to separate the exhaust gas flow into the pair of exhaust gas flows on either side of the flow splitting structure.

3. The inlet assembly of claim 1 or 2, wherein the flow dividing structure is centrally located in the nozzle bore.

4. The inlet assembly of claim 1 , wherein the flow splitting structure is configured to separate the exhaust gas flow into the pair of exhaust gas flows adjacent a surface of the nozzle bore.

5. The inlet assembly of claim 1 , wherein the flow splitter structure is configured to divide the nozzle bore into a pair of nozzle bores.

6. 6. The inlet assembly of claim 5, wherein the inlet nozzle defines a single nozzle bore extending from the non-circular inlet opening to the flow diverter structure, and the pair of nozzle bores extend from the flow diverter structure to a pair of the outlet openings.

7. The inlet assembly of claim 5 or 6, wherein the inlet nozzle defines a lofted transition from the single nozzle bore to the pair of nozzle bores through the flow dividing structure.

8. 8. The inlet assembly of claim 1 , wherein the inlet nozzle has a longitudinal length extending in a primary direction of the exhaust gas flow, and the flow dividing structure reduces a cross-sectional area of ​​the nozzle bore along the longitudinal axis.

9. The inlet assembly of claim 8 , wherein the flow diverting structure is positioned no closer to the non-circular inlet opening than 20% of the longitudinal length.

10. The inlet assembly of claim 1 , wherein the flow dividing structure is shaped to present a surface oriented with a transverse component relative to the longitudinal axis.

11. The inlet assembly of claim 10, wherein the surface is at least one of oriented at between 20° and 70° to the longitudinal axis and is at least one of planar and curved.

12. 12. The inlet assembly of claim 10, wherein the flow diverting structure is shaped to present a pair of the surfaces that are mirror images with respect to the longitudinal axis and at least one of a major axis and a minor axis of the nozzle bore extending transversely to the longitudinal axis.

13. 13. The inlet assembly of claim 1, comprising a baffle disposed upstream of the flow dividing structure, the baffle defining a baffle opening, the baffle opening having a reduced cross-sectional area compared to a cross-sectional area of ​​the nozzle bore adjacent the baffle.

14. receiving an exhaust stream at an inlet assembly for an abatement apparatus, the inlet assembly including an inlet nozzle defining a non-circular inlet opening coupleable to an inlet conduit supplying an exhaust gas stream for treatment by the abatement apparatus, at least one outlet opening, and a nozzle bore extending along a longitudinal axis between the non-circular inlet opening and the outlet opening, the nozzle bore defining an inlet section extending from the non-circular inlet opening, a flow dividing structure disposed downstream of the inlet section, and an outlet section extending to the outlet opening; conveying the exhaust gas flow from the non-circular inlet opening to the flow dividing structure; separating the exhaust gas stream into at least a pair of exhaust gas streams using the flow splitting structure; conveying the pair of exhaust gas streams to the at least one outlet opening for delivery to a treatment chamber of the abatement apparatus; Including, The inlet nozzle defines the nozzle bore as a single nozzle bore extending from the non-circular inlet opening to the outlet opening and having the flow diverter structure disposed therein.

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