INLET ASSEMBLY FOR AN ABATEMENT APPARATUS

Abstract

An inlet assembly for an abatement apparatus includes an inlet nozzle defining a non-circular inlet aperture coupleable with an inlet conduit providing an effluent gas stream for treatment by the abatement apparatus, at least one outlet aperture and a nozzle bore extending along a longitudinal axis between the non-circular inlet aperture and the outlet aperture for conveying the effluent gas stream from the non-circular inlet aperture to the outlet aperture for delivery to a treatment chamber of the abatement apparatus, the nozzle bore defining an inlet portion extending from the non-circular inlet aperture, a flow-dividing structure positioned downstream of the inlet portion and configured to separate the effluent gas stream into at least a pair of effluent gas streams and an outlet portion extending to the outlet aperture and configured to convey the pair of effluent gas streams to the treatment chamber of the abatement apparatus.

Claims

1. An inlet assembly for an abatement apparatus, said inlet assembly comprising: an inlet nozzle defining a non-circular inlet aperture coupleable with an inlet conduit providing an effluent gas stream for treatment by said an abatement apparatus, at least one outlet aperture and a nozzle bore extending along a longitudinal axis between said non-circular inlet aperture and said outlet aperture for conveying said effluent gas stream from said non-circular inlet aperture to said outlet aperture for delivery to a treatment chamber of said abatement apparatus, said nozzle bore defining an inlet portion extending from said non-circular inlet aperture, a flow-dividing structure positioned downstream of said inlet portion and configured to separate said effluent gas stream into at least a pair of effluent gas streams and an outlet portion extending to said outlet aperture and configured to convey said pair of effluent gas streams to said treatment chamber of said an abatement apparatus.

2. The inlet assembly of claim 1, wherein said flow-dividing structure is configured to separate said effluent gas stream into said pair of effluent gas streams flowing either side of said flow-dividing structure.

3. The inlet assembly of claim 1, wherein said flow-dividing structure is centrally located within said nozzle bore.

4. The inlet assembly of claim 1, wherein said flow-dividing structure is configured to separate said effluent gas stream into said pair of effluent gas streams flowing proximate a surface of said nozzle bore.

5. The inlet assembly of claim 1, wherein said inlet nozzle defines said nozzle bore as a single nozzle bore extending from said non-circular inlet aperture to said outlet aperture with said flow-dividing structure located therein.

6. The inlet assembly of claim 1, wherein said flow-dividing structure is configured to divide said nozzle bore into a pair of nozzle bores.

7. The inlet assembly of claim 6, wherein said inlet nozzle defines a single nozzle bore extending from said non-circular inlet aperture to said flow-dividing structure and said pair of nozzle bores extending from said flow-dividing structure to a pair of said outlet apertures.

8. The inlet assembly of claim 6, wherein said inlet nozzle defines a lofted transition from said single nozzle bore to said pair of nozzle bores via said flow-dividing structure.

9. The inlet assembly of claim 1, wherein said inlet nozzle has a longitudinal length extending in a major direction of flow of said effluent stream and said flow-dividing structure reduces a cross-sectional area of said nozzle bore along said longitudinal axis.

10. The inlet assembly of claim 9, wherein said flow-dividing structure is positioned no closer to said non-circular inlet aperture than 20% of said longitudinal length.

11. The inlet assembly of claim 1, wherein said flow-dividing structure is shaped to present a surface orientated with a transverse component with respect to said longitudinal axis.

12. The inlet assembly of claim 11, wherein said surface is at least one of: orientated by between 20° to 70° with respect to said longitudinal axis; and at least one of planar and curved.

13. The inlet assembly of claim 11, wherein said flow-dividing structure is shaped to present a pair of said surfaces mirrored about at least one of said longitudinal axis and a major and a minor axis of said nozzle bore extending transverse to said longitudinal axis.

14. The inlet assembly of claim 1, comprising a baffle positioned upstream of said flow-dividing structure, said baffle defining a baffle aperture, said baffle aperture having a reduced cross-sectional area compared to that of said nozzle bore adjacent said baffle.

15. A method, comprising: receiving an effluent stream at an inlet assembly for an abatement apparatus, the inlet assembly comprising an inlet nozzle defining a non-circular inlet aperture coupleable with an inlet conduit providing the effluent gas stream for treatment by the abatement apparatus, at least one outlet aperture and a nozzle bore extending along a longitudinal axis between the non-circular inlet aperture and the outlet aperture, the nozzle bore defining an inlet portion extending from the non-circular inlet aperture, a flow-dividing structure positioned downstream of the inlet portion, and an outlet portion extending to the outlet aperture; conveying the effluent gas stream from the non-circular inlet aperture to the flow-dividing structure; separating the effluent gas stream into at least a pair of effluent gas streams with the flow-dividing structure; and conveying the pair of effluent gas streams to the at least one outlet aperture for delivery to a treatment chamber of the abatement apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which:

[0031] FIGS. 1 and 2 illustrate a head assembly according to one embodiment coupled with a radiant burner assembly;

[0032] FIG. 3 is a cross-sectional view through an inlet nozzle according to one embodiment;

[0033] FIG. 4 is a cross-sectional view through an inlet nozzle according to one embodiment;

[0034] FIGS. 5A and 5B illustrate an inlet nozzle according to one embodiment; and

[0035] FIG. 6 illustrates a baffle plate positioned upstream the inlet nozzle.

DETAILED DESCRIPTION

[0036] Before discussing the embodiments in any more detail, first an overview will be provided. Embodiments provide a burner inlet assembly. The burner inlet assembly comprises a dividing structure or weir which separates the received effluent gas stream into multiple separate effluent gas streams for delivery into the treatment chamber of an abatement apparatus. The presence of the flow separator helps to maintain separate effluent streams, even at low flow rates. This reduces the distance along which diffusion reaction needs to occur, compared to that of an equivalent single effluent gas stream, which improves the abatement performance, particularly at low flow rates.

[0037] Although the following embodiments describe the use of radiant burners, it will be appreciated that the inlet assembly may be used with any of a number of different burners such as, for example, turbulent flame burners or electrically heated oxidisers. Radiant burners are well known in the art, such as that described in EP 0 694 735.

Head Assembly

[0038] FIGS. 1 and 2 illustrate a head assembly, generally 10, according to one embodiment coupled with a radiant burner assembly 100. 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 via a plenum (not shown) within a plenum housing 120 to the outer burner 110 and a conduit (not shown) to the inner burner 130.

[0039] The head assembly 10 comprises three main sets of components. The first is a metallic (typically stainless steel) housing 20, which provides the necessary mechanical strength and configuration for coupling with the radiant burner assembly 100. The second is an insulator 30 which is provided within the housing 20 and which helps to reduce heat loss from within a combustion chamber defined between the inner burner 130 and the outer burner 110 of the radiant burner assembly 100, as well as to protect the housing 20 and items coupled thereto from the heat generated within the combustion chamber. The third are inlet assemblies 60 which receive a nozzle in a void 50 and are received by a series of identical, standardized apertures 40 (see FIG. 2) provided in the housing 20. This arrangement enables individual inlet assemblies 60 to be removed for maintenance, without needing to remove or dissemble the complete head assembly 10 from the remainder of the radiant burner assembly 100.

[0040] The embodiment shown in FIG. 1 utilises five identical inlet assemblies 60, each mounted within a corresponding aperture 40, the sixth aperture is shown vacant. It will be appreciated that not every aperture 40 may be filled with an inlet assembly 60 which receives an effluent or process fluid, or other fluid via its nozzle, and may instead receive a blanking inlet assembly to completely fill the aperture 40, or may instead receive an instrumentation inlet assembly housing sensors in order to monitor the conditions within the radiant burner. Also, it will be appreciated that greater or fewer than six apertures 40 may be provided, that these need not be located circumferentially around the housing, and that they need not be located symmetrically either.

[0041] As can also be seen in FIGS. 1 and 2, additional apertures are provided in the housing 20 in order to provide for other items such as, for example, a sight glass 70 and a pilot 75A.

[0042] The inlet assemblies 60 are provided with an insulator to protect the structure of the inlet assemblies 60 from the combustion chamber. The inlet assemblies 60 are retained using suitable fixings such as, for example, bolts (not shown) which are removed in order to facilitate their removal and these are also protected with an insulator (not shown). The nozzles have one or more outlet aperture and a baffle portion as will be explained in more detail below.

Inlet Nozzle—1.SUP.st .Embodiment

[0043] FIG. 3 is a cross-sectional view through an inlet nozzle 200A according to one embodiment. The inlet nozzle 200A is mirrored about the cross-sectional view shown in FIG. 3. The inlet nozzles 200A fit into the voids 50, which are typically shaped to fit its external surface. The inlet nozzle 200A comprises an inlet aperture 210A, an outlet aperture 220A and a nozzle bore 230A extending along a longitudinal axis A between the inlet aperture 210A and the outlet aperture 220A. In this example, the nozzle bore 230A has an obround cross section. The obround comprises two semicircles connected by parallel lines tangential to their endpoints. Accordingly, the inlet nozzle forms a flattened tube having parallel major faces and hemi-cylindrical joining faces. The outer wall defining the nozzle bore 230A has a uniform cross-section along the longitudinal axis A.

[0044] Within the nozzle bore 230A is provided a flow divider 240A. The flow divider 240A extends from and between the two internal major faces of the nozzle bore 230A. In particular, the flow divider 240A presents a curved surface upstanding from the major surfaces of the nozzle bore 230A and are shaped to split the flow of the effluent stream traveling generally along the longitudinal axis A, creating two streams flowing in the vicinity of the rounded portions of the nozzle bore 230A. The curved surface of the flow divider 240A extends from a central location towards the curved portions of the nozzle bore 230A, forming an arch-shaped structure shown in cross-section in FIG. 3, whose leading surface is formed as a generally cylindrical recess.

[0045] In operation, the effluent stream is introduced through the inlet aperture 210A and travels generally in the direction of the longitudinal axis A. The effluent stream is split into two effluent streams, one passing on either side of the flow divider 240A and exiting the outlet aperture 220A generally as a pair of effluent streams.

Inlet Nozzle—2.SUP.nd .Embodiment

[0046] 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 divider 240B. The flow divider 240B extends from and between the two internal major faces of the nozzle bore 230B. In particular, the flow divider 240B is formed from a pair of planar surfaces upstanding from the major internal surfaces of the nozzle bore 230B and are shaped to split the flow of the effluent stream traveling generally along the longitudinal axis A, creating two streams flowing in the vicinity of the rounded portions of the nozzle bore 230B. The planar surfaces of the flow divider 240B extend from a central location towards the curved portions of the nozzle bore 230B, forming an inverted V-shaped structure shown in cross-section in FIG. 4, whose leading surface is formed as a pair of generally flat surfaces.

[0047] In operation, the effluent stream is introduced through the inlet aperture 210B and travels generally in the direction of the longitudinal axis A. The effluent stream is split into two effluent streams, one passing on either side of the flow divider 240B and exiting the outlet aperture 220B generally as a pair of effluent streams.

Inlet Nozzle—3.SUP.rd .Embodiment

[0048] FIGS. 5A and 5B illustrate an inlet nozzle 200C according to one embodiment. This embodiment is identical to that of FIG. 3 with the exception that the flow divider 240C is extended in the direction of the longitudinal axis A to the position of the outlet apertures 220C, 220D and that portion of the major surface of the nozzle bore 230C which is redundant has been removed. In this embodiment, therefore, the inlet nozzle 200C has one inlet aperture 210C and two outlet apertures 220C, 220D.

[0049] In operation, the effluent stream is introduced through the inlet aperture 210C and travels generally in the direction of the longitudinal axis A. The effluent stream is split into two effluent streams, one passing on either side of the flow divider 240C and exiting the two outlet aperture 220C, 220D as a pair of effluent streams.

[0050] It will be appreciated that the position of the flow dividers 240A, 240B, 240C may be varied to suit flow conditions. Should the flow of the effluent stream entering the inlet aperture 210, 210A, 210B, not be uniform or be un-symmetric, the position of the flow dividers 240A, 240B, 240C may be adjusted in the axis transverse to the longitudinal axis A to generate a pair of symmetric effluent gas streams. Also, the position of the flow dividers 240A, 240B, 240C may be varied to alter the distance from the inlet aperture 210A, 210B, 210C to avoid any areas of high turbulence. Also, it will be appreciated that the shape and angle of attack of the pair of surfaces of the flow dividers 240A, 240B, 240C can be varied to suit flow conditions.

Baffle Plate

[0051] In embodiments, a baffle plate 250 is positioned upstream of the flow-dividing structure 240, 240A, 240B, as illustrated in FIG. 6. The baffle plate 250 may be provided within the nozzle bore 230A, 230B, 230, on the inlet aperture 210A, 210B, 210C or (as illustrated) in a coupling 260 which couples with the inlet nozzle 200A, 200B, 200C.

[0052] Accordingly, it can be seen that embodiments provide a sub-divided slot nozzle. This arrangement enhances performance over existing nozzles at low flow rates. In particular, although some existing nozzles can provide for good abatement performance, particularly at higher flow rates, embodiments extend that performance to lower flow rates.

[0053] Typically, in embodiments, the nozzle is constructed from a heat and chemically resistant metal alloy, for example ANC16. The nozzle is conveniently formed by a casting process, for example lost wax casting. The inlet to the nozzle is in the form of an obround aperture being 16 mm internal width on 50 mm centres. This form typically continues parallel for approximately 25% of the total length. Thereafter, a weir or flow-divider is formed in the central portions to urge the flow to adopt 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 centres as the obround inlet. In other embodiments, the weir extends to greater or lesser distances towards the discharge end of the nozzle which retains the same obround form as the inlet. The weir may be in the form of a chevron and may be flat sided or may be radiused.

[0054] Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

[0055] Although elements have been shown or described as separate embodiments above, portions of each embodiment may be combined with all or part of other embodiments described above.

[0056] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are described as example forms of implementing the claims.