Head unit for abatement apparatus

Abstract

A head unit 6 is suitable for an abatement apparatus (1, Fig. 1) and defines an effluent flow conduit 7 which directs an effluent gas flow through the head unit. A surface defining the inner face of t

Description

02 12 25 _k Field The present invention relates to a head unit for an abatement apparatus, preferably wherein said head unit is monolithic. The present invention also relates to an 5 abatement apparatus comprising said head unit, to a method of producing a head unit, and to a method for conveying an effluent gas flow into an abatement apparatus. Background Abatement apparatus are known and are typically used for treating an effluent gas flow from a manufacturing process tool used in, for example, the semiconductor, solar 10 or flat panel display manufacturing industry. Harmful greenhouse gases and other toxic compounds may be present in the effluent gas flow pumped from such manufacturing process tools. Therefore, the effluent gas flow must be treated to remove selected gases and solids therefrom before being vented to the atmosphere. Prior art abatement apparatus demonstrate excellent performance in destruction 5 efficiency of harmful greenhouse gas emissions and other toxic compounds. However, over time, solid deposits may build up within the head unit of the abatement apparatus. This may reduce destruction efficiency and clog the head unit. Accordingly, preventative maintenance of the head unit is required on a regular basis. Said maintenance is time consuming and costly as the head unit comprises many 20 interconnected components and seals that must be disconnected, reconnected, and leak checked. There is a desire to improve the performance and serviceability of head units. There is also a desire to provide head units of abatement apparatus which provide improved passive mixing of gas flow passing therethrough. 25 The present invention aims to solve, at least in part, these and other problems associated with abatement apparatus of the prior art. Summary In an aspect, the present invention provides a head unit, according to claim 1, for arrangement at an inlet of a combustion chamber of an abatement apparatus 02 12 25 _k The head unit may have a generally cylindrical body. The head unit may have a generally planar portion. The head unit may be a head plate. The head unit may be configured to cap the combustion chamber of the abatement apparatus. Typically, the head unit may be the last stage of gas flow conditioning (e.g. mixing, 5 redirecting and / or realignment) prior to the fluid conveyed therein reaching a combustion chamber. Typically, the head unit may be configured such that effluent gas flow and / or further fluid flow(s) enter a downstream combustion chamber in a generally coaxial flow direction, the flow direction being substantially coaxial with a longitudinal axis of the head unit. In some embodiments, the head unit may be a head 10 plate. When arranged at an inlet of a combustion chamber of the abatement apparatus, the head unit may define a portion of the combustion chamber. Specifically, the head unit may define a portion of the surface defining the combustion chamber. The head unit may have an upstream side that faces generally away from the combustion chamber 5 when in use, and a downstream side that faces towards the combustion chamber when in use. Preferably, in use, a surface of the generally planar portion of the head unit may define a portion of the surface of the combustion chamber. For the purposes of the present invention, the terms “upstream” and “downstream” may refer to the relative positioning of components along the flow path of the effluent 20 gas flow. The head unit may be configured to receive incoming effluent gas flows from one or more sources. For example, the effluent gas flow may be the exhaust flow from one or more process tools. The head unit may be configured to direct said gas flow(s) into the combustion chamber of the abatement apparatus. 25 The effluent flow conduit may have a conduit inlet through which the effluent gas flow enters the effluent flow conduit. The conduit inlet may be on an upstream side of the head unit. The effluent flow conduit may also have a conduit outlet through which the effluent gas flow exits the effluent flow conduit. The conduit outlet may be on a downstream side of the head unit. The conduit outlet may be configured to convey the 30 effluent gas flow directly into the combustion chamber, or alternatively, into a further component, such as an inlet nozzle. 02 12 25 _k The effluent flow conduit may be non-linear. For the avoidance of doubt, the head unit defining an effluent flow conduit means that the surface of the head unit defining the effluent flow conduit directly contacts the effluent gas flow during use. Preferably, the surface of the head unit defining the inner 5 face of the effluent gas conduit may be an internal surface of the head unit. In contrast, head units of prior art abatement apparatus typically have an aperture through which a nozzle is inserted, with the nozzle defining a flow path for the effluent gas flow rather than the head unit itself. In the present invention, the surface of the head unit defining the inner face of the effluent flow conduit may directly contact the effluent gas flow, 10 enabling improved control of the flow path of the effluent gas flow. For the avoidance of doubt, the first and second directions are different. Typically, the first direction may be the major direction of flow of the effluent gas flow. In some embodiments, when in use, the first direction may be generally downwards. The second direction may be generally radially inward. The second direction may be at an 5 angle of from about 90° to about 180° to the first direction. The smooth curved section may substantially continuously transition the direction of flow of the effluent gas flow from the first direction to the second direction. Said substantially continuous transition may occur along the length of the smooth curved section. The first section of conduit may be upstream of the second section of conduit. The 20 smooth curved section may be continuous with the first section of conduit and the second section of conduit, respectively. Preferably, there may be substantially no corners or edges defining the intersection of the smooth curved section with the first section of conduit and / or second section of conduit. The smooth curved section may be discrete from the first section of conduit and / or the second section of conduit. The 25 smooth curved section may have a length extending between the first section and the second section. The effluent flow conduit may comprise a substantially linear section. Alternatively, substantially the entire effluent flow conduit may be a smooth curve. In use, the smooth curved section may change the direction of the effluent gas flow as it passes through 30 the head unit. In other words, the effluent flow conduit may define an arced flow path through the head unit. For the avoidance of doubt, a smooth curved section may refer 02 12 25 _k to the effluent flow conduit being configured to transition the direction of the effluent gas flow from the first direction to the second direction within the head unit. Typically, the effluent flow conduit may have a circular or elliptical cross-section. Preferably, the surface defining the smooth curved section of the effluent flow conduit 5 may be substantially free from angles or comers. More preferably, the surface defining the effluent flow conduit may be substantially free from angles or corners. Preferably, the effluent flow conduit may be defined by a single surface of the head unit. The present inventors have found that sharp changes in the direction of flow of the effluent gas flow may lead to increased condensation and deposit formation. The head 10 unit of the present invention provides a solution to this problem, by enabling smoothed redirection of the effluent gas flow within the head unit. Therefore, the likelihood of deposit formation within the effluent flow conduit is reduced, and the head unit of the present invention may require less frequent maintenance. Typically, the surface of the head unit defining the effluent flow conduit may be 5 arranged such that the angle of incidence between the major direction of flow of the effluent gas flow and the surface is less than or equal to about 45°. Typically, the major direction of flow of the effluent gas flow may be towards the combustion chamber of the abatement apparatus. The major direction of flow of the effluent gas flow may be defined by the direction of flow of the effluent gas flow through 20 the conduit inlet during operation. The major direction of flow of the effluent gas flow may be generally towards the combustion chamber. In some embodiments, the head unit is arranged above the combustion chamber. Therefore, the major direction of flow of the effluent gas flow may be generally downwards. As the effluent gas flow travels through the effluent flow conduit, the surface defining 25 the effluent flow conduit may interact with the effluent gas flow to change the direction thereof. The angle of incidence may be the angle at which the effluent gas flow traveling in the major direction of flow impacts the surface. Said surface may be the surface defining the smooth curved section of the conduit. Advantageously, ensuring that the angle of incidence between the major direction of flow of the effluent gas flow 30 is less than or equal to about 45° may reduce the formation of deposits within the effluent flow conduit. 02 12 25 _k In embodiments wherein the effluent flow conduit defines more than one smooth curved section (i.e., more than one change of direction of flow), the angle of incidence between the major direction of flow of the effluent gas flow prior to each smooth curved section and the surface defining the smooth curved section may be less than or equal 5 to about 45°. In embodiments, the smooth curved section may have a bend radius which is at least 1.5 times the diameter of the smooth curved section. In other words, the smooth curved section may be substantially devoid of any sharp bends, i.e. bends which would lead to a build-up of contaminants or create pressure drops within the effluent flow 10 conduit during otherwise normal use conditions. Potential pressure drops within the effluent flow conduit may be substantially eliminated or at least significantly reduced. Typically, the effluent flow conduit may comprise a tapered section. Preferably, the tapered section of the effluent flow conduit may be located downstream of the smooth curved section of the effluent flow conduit. The tapered section may be the first section. 5 Additionally, or alternatively, the tapered section may be the second section. Additionally, or alternatively, the tapered section may be the smooth curved section. The tapered section may be defined as a section of the effluent flow conduit wherein the cross-sectional area at the start of the section is larger than the cross-sectional area at the end of the section. Preferably, the tapered section may be a substantially 20 uniform taper. Alternatively, the tapered section may be a non-uniform taper. Preferably, the cross-sectional area of the effluent flow conduit may continuously decrease along the tapered section. The volume defined by the tapered section of the effluent flow conduit may be substantially frusto-conical. Advantageously, providing a tapered section may improve the mixing of the effluent 25 gas flow within the effluent flow conduit of the head unit. Improved mixing of the effluent gas flow may improve the destruction and removal efficiency (DRE) of the abatement apparatus. The tapered section may improve mixing of the effluent gas flow with any additives that have been injected into the effluent gas flow. The head unit is monolithic. For the purposes of the present invention, monolithic may 30 be defined as the head unit being a single, unitary component. In other words, the monolithic head unit may be in the form of a single piece of material. The monolithic 02 12 25 _k head unit may include components that are welded together, thereby effectively becoming a single, unitary component. The monolithic head unit may be connected to further components of the abatement apparatus, but said components do not form part of the monolithic head unit. For the 5 purposes of the present invention, the monolithic head unit may not include any components that are removably attached thereto. For example, components that are fastened, bolted, screwed, or otherwise connected via removable fixing(s) may not be defined as forming part of the monolithic head unit. Furthermore, the monolithic head unit may not include components that are removably inserted within the monolithic 10 head unit. In some embodiments, the effluent flow conduit may be monolithic. In other words, the surface of the head unit defining the first section, the smooth curved section, and the second section of the effluent flow conduit may be monolithic. Typically, the head unit may comprise one or more baffles arranged in the effluent flow 5 conduit and configured to redirect the effluent gas flow. Preferably, the baffle(s) may comprise one or more louvers. Preferably, the head unit may comprise a plurality of louvers. Advantageously, the baffle(s) may improve mixing of the effluent gas flow as it passes through the head unit. This may improve the performance of the abatement apparatus. 20 The head unit may comprise one or more heating elements arranged within the effluent flow conduit. The heating elements may be configured to heat the effluent gas flow as it passes through the effluent flow conduit. In some embodiments, the heating element(s) may be arranged on, or integrated with, a baffle. Typically, the head unit may comprise a plurality of effluent flow conduits. Preferably, 25 the head unit may comprise from about 4 to about 8 effluent flow conduits. Preferably, each effluent flow conduit may be as defined hereinbefore. Each effluent flow conduit may be configured to be coupled to a process tool during operation. In some embodiments, each effluent flow conduit may be configured to be coupled to a separate process tool during operation. 30 Typically, the effluent flow conduits may be arranged about a central axis of the head unit. The effluent flow conduits may be arranged in a generally circular array when 02 12 25 _k viewed along a central axis of the head unit. When in use, the central axis of the head unit may be substantially coaxial with a central axis of the combustion chamber. Preferably, each effluent flow conduit is configured to direct the effluent gas flow generally radially inwardly as it passes through the head unit. For each effluent flow 5 conduit, the central axis at the conduit inlet may be offset from the central axis at the conduit outlet. In some embodiments, the central axis at the conduit inlet may be substantially parallel with the central axis at the conduit outlet. In alternative embodiments, the angle between the central axis at the conduit inlet and the central axis at the conduit outlet may be from about 90° to about 180°. Preferably, the angle 10 between the central axis at the conduit inlet and the central axis at the conduit outlet may be from about 120° to about 180°. When viewed along the central axis of the head unit, the or each conduit outlet may be generally radially inward of the or each conduit inlet. The head unit of the present invention may enable the alignment of the effluent flow 5 conduits within the head unit. Space within an abatement apparatus is typically limited, particularly in embodiments with a plurality of effluent flow conduits. The head unit of the present invention may simplify the arrangement of the abatement apparatus, as the overall component count may be reduced. Typically, the head unit may define one or more reagent flow conduits for conveying a 20 reagent flow towards the effluent gas flow. Additionally or alternatively, the head unit may define one or more inert gas conduits for conveying a substantially inert gas towards the effluent gas flow. The reagent flow conduit(s) and / or the inert gas conduits may be referred to as inject flow conduit(s). Preferably, the or each inject flow conduit may have an inject flow contact surface for 25 conveying an inject fluid towards the effluent flow. The inject flow contact surface may be defined by the head unit. In other words, the inject flow conduit(s) may be substantially internally routed within the head unit. In embodiments, an inject flow conduit may have a generally lateral primary flow direction. In other words, an inject flow conduit may extend substantially perpendicular 30 to a major axis of the head unit. In embodiments, the or each inject flow conduit extends substantially laterally within the head unit. 02 12 25 _k Advantageously, routing an inject flow conduit internally within the head unit may enable improved thermal control of the head unit. Furthermore, internally routing the effluent flow conduit and the inject flow conduit may reduce the number of connections and seals around the head unit. This may therefore provide more free space within the 5 abatement apparatus. Such embodiments may reduce downtime during servicing as fewer leak checks may be required. Typically, the head unit may comprise a metallic material. Preferably, the head unit may comprise an aluminium alloy or a stainless steel alloy. Advantageously, providing an aluminium alloy head unit may improve thermal conductivity and reduce the weight 10 of the head unit in comparison with alternative materials. This may aid in serviceability of the head unit. In some embodiments, a surface layer may be present on one or more surfaces of the head unit. Preferably, a surface layer may be present on the surface(s) defining the effluent flow conduit(s). For example, a nickel surface layer may be present on the 5 surface(s) defining the effluent flow conduit(s). Advantageously, this may improve the corrosion resistance of the effluent flow conduit(s). The head unit may comprise a flange configured for connection to an inlet of the combustion chamber. In use, the flange may be connected to the inlet of the combustion chamber of the abatement apparatus by one or more fasteners and seals. 20 Preferably, the flange may be configured to match the dimensions of existing head units of abatement apparatus, to enable the head unit of the present invention to be retrofitted to existing abatement apparatus. For example, the head unit may be configured to be fitted to an Atlas abatement apparatus as produced by Edwards Limited. 25 Typically, the head unit may define at least one channel configured to receive an inlet nozzle. The effluent flow conduit may be configured such that the effluent gas flow exiting the effluent flow conduit enters the inlet nozzle. The head unit may define a channel that corresponds to each effluent flow conduit. Each channel may be configured to receive an inlet nozzle, or “plug”, during use. The or each channel may 30 be a linear channel. The or each channel may extend from an upstream side of the head unit to a downstream side of the head unit. Advantageously, such an 02 12 25 _k arrangement may enable the inlet nozzle(s) to be easily removed from the head unit for maintenance. In alternative embodiments, the head unit may define the nozzle configured to inject the effluent gas flow into the combustion chamber. 5 Ina further aspect, the present invention provides an abatement apparatus according to claim 11. The abatement apparatus comprises a main body defining a combustion chamber having an inlet and an outlet. The abatement apparatus further comprises a head unit according to any embodiment of the preceding aspect. The head unit is arranged at the inlet of the combustion chamber and configured to direct an effluent 10 gas flow into the combustion chamber. Advantages and embodiments will be as set out in relation to the preceding aspect. It will be appreciated that the abatement apparatus may include further features that will be known to the skilled person. In a further aspect, the present invention provides a method of producing a head unit 5 according to any embodiment of an aspect herein. The method comprises producing the head unit by additive manufacture. Preferably, the additive manufacture comprises a powder bed fusion technique, for example direct metal laser sintering. Preferably, the head unit is substantially entirely produced via an additive manufacturing technique as a monolithic component. Alternatively, a portion of the head unit is 20 produced via an additive manufacturing technique. Advantageously, the method beneficially enables highly reproducible manufacturing of components with complex geometries from a variety of materials, using minimal raw materials, and without requiring expensive tooling specific to each component produced. 25 Typically, the method may further comprise the step of adding a surface layer to the surface defining the effluent flow conduit. Preferably, the step may comprise adding a nickel surface layer. In a further aspect, the present invention provides a method of conveying an effluent gas flow into an abatement apparatus. The method comprises the steps of: 30 a. providing an abatement apparatus as defined in an aspect set out elsewhere herein; 02 12 25 _k b. conveying an effluent gas flow through the effluent flow conduit of the head unit; c. conveying the effluent gas flow into the combustion chamber of the abatement apparatus. For the avoidance of doubt, all aspects and embodiments described herein may be 5 combined, mutatis mutandis. It is also to be understood that this invention is not limited to the embodiments and aspects set forth in the following detailed description or illustrated in the drawings. The invention may be implemented in various other embodiments and is capable of being implemented in alternative ways not expressly disclosed herein. 10 Brief Description of Figures Preferred features of the present invention will now be described, by way of example, with reference to the accompanying figures, in which: Figure 1 shows a cross-sectional view of a portion of an abatement apparatus according to the prior art; 5 Figure 2 shows a cross-sectional view of portion of an abatement apparatus including a head unit in accordance with an embodiment of the present invention; and Figure 3 shows a head unit in accordance with an embodiment of the present invention. Detailed Description of Figures 20 Figure 1 illustrates a cross-sectional view of a portion of an abatement apparatus (1) according to the prior art. The arrows indicate the flow path of the effluent gas flow (Feff) through the head unit and into the abatement apparatus during use. An exhaust line (2) conveys the effluent gas flow (Feff) into a chamber of the head unit (3). The effluent gas flow (Feff) then turns sharply by 90°, and is conveyed into an inlet nozzle 25 (4). The inlet nozzle is inserted through a head plate (5) of the head unit (3). The effluent gas flow (Feff) turns sharply by 90° within the inlet nozzle (4) and is conveyed towards the combustion chamber of the abatement apparatus (not shown). The present inventors have found that when the effluent gas flow (Feff) is conveyed around a sharp corner, and the effluent gas flow (Feff) impacts the surface that is 30 perpendicular to the major direction of flow the likelihood of deposition thereon 02 12 25 _k increases. Accordingly, head units (3) of the prior art suffer from significant deposition over time, requiring frequent maintenance. Figure 2 illustrates a cross-sectional view of portion of an abatement apparatus including a head unit (6) in accordance with an embodiment of the present invention. 5 A surface of the head unit (6) defines an effluent flow conduit (7). The effluent flow conduit (7) is configured to direct an effluent gas flow through the head unit (6) during use. The surface defining the inner face of the effluent flow conduit (7) provides a first section (8) for directing effluent flow in a first direction (Di), and a second section for directing the effluent flow in a second direction (D2). The surface further defines a 10 smooth curved section (9) of conduit between said first section (8) and second section (10) configured to transition the direction of flow of the effluent gas flow from said first direction (Di) to said second direction (D2) along the length of the smooth curved section (9). In this embodiment, the head unit (6) is monolithic. The head unit (6) is connected to 5 other components of the abatement apparatus. The surface of the head unit (6) defining the effluent flow conduit (7) is arranged such that the angle of incidence between the major direction of flow of the effluent gas flow and the surface is less than about 45°. This may reduce the likelihood of deposit formation within the head unit (6), as the change of direction of the effluent gas flow 20 through the head unit is gradual. The effluent flow conduit (7) further comprises a tapered section (10). The tapered section (10) is downstream of the curved section. In this embodiment, the tapered section (10) defines the second section. The tapered section (10) may improve the mixing of the effluent gas flow. The effluent flow conduit (7) directs the effluent gas 25 flow generally radially inwardly, i.e. towards the central axis of the head unit (not shown). The head unit (6) defines a plurality of reagent flow conduits (11). The reagent flow conduits (11) are configured to convey reagent flows (e.g. fuel, oxidant) within the monolithic head unit for injection into the effluent gas flow. 30 The head unit (6) comprises a flange (12) configured for connection with an inlet of the combustion chamber of the abatement apparatus. The head unit (6) further comprises 02 12 25 _k a channel (13) that has an inlet nozzle (14) or “plug” inserted therein. The effluent flow conduit (7) is configured such that the effluent gas flow exiting the effluent flow conduit enters the inlet nozzle (14) for injection into the combustion chamber of the abatement apparatus. Additionally, the inlet nozzle (14) comprises channels that connect to the 5 reagent gas conduits (11) of the head unit (6). Figure 3 illustrates a head unit (15) in accordance with an embodiment of the present invention. With the exception of the inlet nozzles (16) received within channels of the head unit (15), the head unit (15) is monolithic. In other words, the head unit (15) is a single piece of material. 10 The head unit (15) is a head plate (17). The head unit (15) comprises a plurality of effluent flow conduits (18). In this embodiment, the head unit (15) comprises six effluent flow conduits (18). The effluent flow conduits (18) are as defined elsewhere herein. The majority of the effluent flow conduits (18) are arranged on an upstream side of the head unit (15). The effluent flow conduits (18) each extend through the 5 head unit (15) and define a flow path for effluent gas flow to pass into the combustion chamber of the abatement apparatus (not shown) during use. At a conduit inlet of each of the effluent flow conduits (18), there is a flange (19). The flange (19) enables the connection of the effluent flow conduit to a gas line (not shown) that conveys the effluent gas flow from the process tool. 20 The head unit (15) further comprises a plurality of inject ports (20). The inject ports (20) define the entrance to inject flow conduits that are within the head unit (15). The inject flow conduits define a flow path for inject gases (e.g. fuel, oxidant, inert gas). When viewed from above, the inject ports (20) are all located in a single minor sector of the head unit (15). In this embodiment, the inject ports (20) are located radially 25 outward of the effluent flow conduits (18). Typically, the head unit (15) may be manufactured using an additive manufacturing technique. For example, the head unit (15) may be manufactured by direct metal laser sintering. 30 Reference Key 1. Abatement apparatus (prior art) 2. Exhaust line (prior art) 3. Head unit (prior art) 5 4. Inlet nozzle (prior art) 5. Head plate (prior art) 6. Head unit 7. Effluent flow conduit 8. First section 10 9. Smooth curved section 10. Tapered section 11. Reagent flow conduit 12. Flange 13. Channel L015 14. Inlet nozzle CXI 15. Head unit C\j 16. Inlet nozzle 17. Head plate CM 18. Effluent flow conduit ^^20 19. Flange

Claims

02 12 251. A head unit for arrangement at an inlet of a combustion chamber of an abatement apparatus;wherein a surface of the head unit defines an effluent flow conduit configured 5 to direct an effluent gas flow through the head unit, andwherein a surface defining the inner face of the effluent flow conduit provides a first section of conduit for directing effluent flow in a first direction and second section of conduit for directing effluent flow in a second direction, and a smooth curved section of conduit between said first section and second10 section configured to transition the direction of flow of the effluent gas flow fromsaid first direction to said second direction along the length of the smooth curved section, wherein the head unit is monolithic and additively manufactured.5 2. The head unit according to claim 1, wherein the surface of the head unit definingthe effluent flow conduit is arranged such that the angle of incidence between the major direction of flow of the effluent gas flow and the surface is less than or equal to about 45°.0 3. The head unit according to claim 1 or claim 2, wherein the effluent flow conduitcomprises a tapered section, preferably wherein the tapered section of the effluent flow conduit is located downstream of the smooth curved section of the effluent flow conduit.

4. The head unit according to any preceding claim, further comprising one or more baffles arranged in the effluent flow conduit and configured to redirect the effluent gas flow.

5. The head unit according to any preceding claim, comprising a plurality of effluent flow conduits, preferably 4 to 8 effluent flow conduits.02 12 256. The head unit according to claim 5, wherein the effluent flow conduits are arranged about a central axis of the head unit, preferably wherein each effluent flow conduit is configured to direct the effluent gas flow generally radially inwardly as it passes through the head unit.

57. The head unit according to any preceding claim, wherein the head unit defines one or more reagent flow conduits for conveying a reagent flow towards the effluent gas flow, and / or wherein the head unit defines one or more inert gas conduits for conveying a substantially inert gas towards the effluent gas flow.

108. The head unit according to any preceding claim, wherein the head unit comprises of a metallic material, preferably wherein the head unit comprises of an aluminium alloy or a stainless steel alloy.15 9. The head unit according to any preceding claim, wherein the head unitcomprises a flange configured for connection to an inlet of the combustion chamber.

10. The head unit according to any preceding claim, wherein the head unit defines 20 at least one channel configured to receive an inlet nozzle, and wherein theeffluent flow conduit is configured such that the effluent gas flow exiting the effluent flow conduit enters the inlet nozzle.

11. An abatement apparatus comprising:25 a main body defining a combustion chamber having an inlet and an outlet;a head unit according to any preceding claim arranged at the inlet of the combustion chamber and configured to direct an effluent gas flow into the combustion chamber.30 12. A method of producing a head unit according to any of claims 1 to 10 by additivemanufacture.

13. The method according to claim 12 wherein the additive manufacture is by direct metal laser sintering.

14. The method according to claims 12 or 13, further comprising the step of adding a surface layer to the surface defining the effluent flow conduit, preferably a nickel surface layer.

515. A method of conveying an effluent gas flow into an abatement apparatus, comprising the steps of:a. providing an abatement apparatus as defined in claim 11;b. conveying an effluent gas flow through the effluent flow conduit of the 10 head unit;c. conveying the effluent gas flow into the combustion chamber of the abatement apparatus.02 12 25

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