Abatement system

Abstract

The invention provides a head unit for capping a combustion chamber of an abatement system The head unit comprises an outer face and inner face, which inner face, in use, forms an internal surface of the combustion chamber. The head unit further defines a plurality of conduits, each conduit running from the outer face of the head unit t. Each conduit has an outer port at or adjacent said outer face and an inner port at or adjacent said inner face or on surface of an effluent flow conduit. When the head unit is viewed from above, a subset of the outer ports is located in a minor sector of said head unit and at least a portion of said subset of said outer ports have their respective inner port(s) outside of said minor sector of said head unit.

Description

Abatement SystemField

[0001] The present invention relates to an abatement system combustion chamber and, in particular, a head unit for capping a combustion chamber of an abatement system. The head unit may comprise a front-facing manifold comprising substantially all the inject flow inlets for the head unit and / or combustion chamber.Background

[0002] 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 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 before being vented to the atmosphere to remove selected gases and solids therefrom.

[0003] Prior art abatement apparatus demonstrate excellent performance in destruction efficiency of harmful greenhouse gas emissions and other unwanted compounds. However, over time, solid deposits may build up within the head unit of the abatement apparatus, which may cause reduction in destruction efficiency and / or clogging. 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 interconnected components and seals that must be disconnected, reconnected, and leak checked.

[0004] There is a desire to improve the performance and serviceability of abatement apparatus.

[0005] The present invention aims to solve, at least in part, these and other problems associated with abatement apparatus of the prior art.Summary

[0006] Accordingly, in a first aspect, the present invention provides a head unit for capping a combustion chamber of an abatement system. The head unit comprises an outer face and inner face, which inner face, in use, forms an internal surface of the combustion chamber. Thehead unit further defines a plurality of conduits, each conduit running from the outer face of the head unit. Each conduit has an outer port at or adjacent said outer face and an inner port at or adjacent said inner face, or at a surface of an effluent flow conduit. Thus, in use, the conduit may provide a channel from the outer surface of the head unit directly into the combustion chamber and / or into an effluent flow conduit.

[0007] Moreover, when the head unit is viewed from above, a subset of the outer ports is located in an imaginary minor sector of said head unit and at least a portion of said subset of said outer ports have their respective inner port(s) outside of said imaginary minor sector of said head unit.

[0008] The inventors have found that by placing one or more of the inner ports in a disparate sector of the head unit to their respective outer port(s), the outer ports may be distributed independently of the inner ports. Advantageously, this permits the inner ports to be distributed according to functional necessity, whereas the outer ports may be distributed for ease of access and / or serviceability. For instance, the majority, or all, of the outer ports, particularly those for receiving inject flow fluid, of a head unit may be located on a proximal side of said head unit. The proximal side of the head unit may be configured to be adjacent an opening or door of a cabinet of the abatement system, said cabinet housing the combustion chamber. Such an arrangement means that servicing may be conducted while only requiring access from said proximal side of the head unit, for instance via the opening or door.

[0009] In contrast, in known head units, outer ports will often be located substantially vertically above their respective inner ports with nozzles passed therethrough. This results in outer ports being distributed about the entire outer surface of the head unit, with pipework extending thereabove. In which case, servicing may require 360-degree access, complicating servicing and increasing downtime.

[0010] When viewed from above, the head unit will normally have a generally circular crosssection. A circular sector is the portion of a disk (a closed region bounded by a circle) enclosed by two radii and an arc, with the smaller area being known as the minor sector and the larger being the major sector. In the diagram, 0 is the central angle, rthe radius of the circle, and L is the arc length of the minor sector.

[0011] The skilled person will appreciate that where the cross-section of the head unit is noncircular then the minor sector will be understood relate to a minor sector of a smallest enclosing circle of the non-circular cross-section.

[0012] Typically, the head unit may define one or more reagent flow conduits for conveying a reagent flow towards the effluent gas flow and / or combustion chamber. 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).

[0013] In embodiments, the outer port(s) are configured to receive an inject flow. Herein such outer port(s) may be referred to an inject flow outer port(s). Each may have a corresponding inject flow inner port and an inject flow conduit extending therebetween. For the purpose of the invention, inject flow relates to fluid introduced into the head unit and / or combustion chamber and / or effluent flow which is not effluent. Inject flow outer port(s), inner port(s) and conduits do not channel effluent during use. Inject flow may be selected from the group consisting of fuel (e.g. methane or natural gas), oxygen, nitrogen, air (preferably compressed dry air), hydrogen, or ammonia. Where the inject flow is used for cooling the fluid may be selected from the group consisting of nitrogen, dry air, water and purged gas. Preferably, the or each subset of the outer ports are configured to receive an inject flow.

[0014] Preferably, the or each inject flow conduit may have an inject flow contact surface for conveying an inject fluid towards the effluent flow conduit and / or inner surface. 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.

[0015] 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 to amajor axis of the head unit. In embodiments, the or each inject flow conduit extends substantially laterally within the head unit.

[0016] 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(s) and the inject flow conduit(s) may reduce the number of connections and seals around the head unit. This may therefore provide more free space within the abatement apparatus. Such embodiments may reduce downtime during servicing as fewer leak checks may be required.

[0017] In embodiments, the or each inner port is an outlet of the conduit and / or the or each outer port is an inlet of the conduit. Accordingly, in use, fluid will flow from the or each outer port to the or each respective inner port via the or each respective conduit. Preferably, the or each outer port is configured to be coupled to a reversibly attachable external inject flow pipework for delivering inject flow to the outer port and, preferably, on through the conduit.

[0018] The conduit(s) may be defined by a surface of the head unit. That is to say, they may not be formed from separate tubing or pipework. This may reduce the number of joints in the apparatus, reducing the likelihood of leaks and reducing downtime. When the head unit defines the conduit means the surface of the head unit defining the effluent flow conduit directly contacts the fluid flow through the conduit during use. Preferably, the surface of the head unit defining the inner face of fluid conduit may be an internal surface of the head unit.

[0019] 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 fluid flow conduit may directly contact the fluid flow.

[0020] The conduit(s) may extend laterally from the outer port and / or parallel to the transverse plane of the head unit. As such, a conduit may be configured to extend from the minor sector containing the outer port to the location of the inner port. Thereby a specific fluid may be directed to wherever it may be needed while having the outer ports located in a convenient location for servicing. The conduit may also include bends and / or turns and / or may include sections which extend parallel to the radial plane of the head unit. Again, this may provide flexibility in design, allowing outer ports to be located in a convenient location for servicing.

[0021] Preferably, the density of outer ports within the or each outer port-containing minor sector is higher than outside the or each outer port-containing minor sector. In embodiments, particularly those in which the outer ports are inject flow ports, all of the outer ports of the head unit lie within the or a minor sector. Typically, the outer ports may be clustered together on a single side of the head unit. The head unit may thus comprise a front-facing (or proximal) manifold comprising substantially all the inject flow inlet ports for the head unit and / or combustion chamber.

[0022] In embodiments, the minor sector may be defined such that the radially extending edges of the minor sector touch but do not intersect the two outer ports separated by the greatest arc angle, with said outer ports laying wholly within the minor sector. Typically, all of the outer ports lie within the minor sector.

[0023] In embodiments, a portion of the subset of outer ports having their respective inner port(s) outside the minor sector comprises two or more outer ports. Typically, a majority of the outer ports of the head unit have their respective inner ports located outside the minor sector. That said, the head unit may comprise a subset of outer ports that have their respective inner ports within the minor sector.

[0024] In embodiments, the outlet ports may be grouped within two or more independent outer port-containing minor sectors. In said embodiments, each independent outer port-containing minor sector may comprise a separate subset of outer ports. Preferably, the two or more independent outer port-containing minor sectors themselves lie within a larger minor sector of the head unit when viewed from above. When provided in two or more independent outer portcontaining minor segments said segments are usually separates by a distance greater than twice the diameter of an outer port contained therein.

[0025] In embodiments comprising two or more independent minor sectors, the or each independent minor sector may comprise a functional cluster of outer ports. That is to say, the or each cluster of outer ports may relate to or provide a specific function to the head unit. There may for instance be a fuel cluster for receiving fuel and / or nitrogen cluster for receiving nitrogen and / or ammonia cluster for receiving ammonia and / or an oxygen cluster for receiving oxygen and / or a cooling cluster for receiving cooling fluid, and the like. Thus, in embodiments, the or each cluster of outer port(s) may be configured to receive a specific inject flow fluid or fluids.

[0026] Additionally, or alternatively, the outer ports may be configured for delivering inject flow to a specific region of the head unit, for instance delivering inject flow into or adjacent a specific effluent flow conduit or effluent flow outlet. Thus, each cluster may be associated with specific effluent flow conduit of the head unit providing outer ports configured to receive substantially all of the inject flow required for their respective effluent flow conduit.

[0027] Additionally, or alternatively, a separate cluster of outer ports may be configured to receive cooling fluid.

[0028] Typically, the or each outer port-containing minor sector has a central angle, 0, of greater than about 15 degrees. Preferably from about 15 degrees to about 120 degrees, preferably from about 45 degrees to about 90 degrees.

[0029] Typically, the or each outer port has a diameter of from about 5 mm to about 15 mm, preferably about 10 mm. Preferably, the or each as a diameter of from about 5 mm to about 15 mm, preferably about 10 mm.

[0030] In an embodiment, the subset, or subsets, of outer port(s) are located on or adjacent an outer segment of the or each outer port-containing minor sector of said head unit.

[0031] For the purposes of the invention, when the cross-section of the head unit is circular when viewed from above, the outer segment, also known as a circular segment or disk segment, is a region of the disk which is "cut off" from the rest of the disk by a secant or a chord. More formally, the outer segment is a region of two-dimensional space that is bounded by a circular arc of less than TT radians and by the circular chord connecting the endpoints of the arc.

[0032] As shown in the diagram, R is the radius of the arc which forms part of the perimeter of the minor segment, 0 is the central angle subtending the arc in radians, c is the chord length, s is the arc length, h is the sagitta (height) of the segment, and d is the apothem of the segment.

[0033] As with other embodiments, the skilled person will appreciate that where the crosssection of the head unit is non-circular, then the outer segment will be understood relate to an outer segment of a smallest enclosing circle of the non-circular cross-section.

[0034] The skilled person will appreciate that viewed from above means viewed from directly above the central longitudinal axis of the head unit at a distance sufficient to see the entire cross-section of the head unit.

[0035] As discussed above, the head unit may include one or more cooling fluid conduits, preferably wherein an inlet and / or an outlet of the or each cooling fluid conduit is located on an outer face of said head unit, preferably within a, the or each outer port-containing minor sector or segment. Accordingly, the cooling fluid conduit may be configured so that cooling fluid may be looped into, around and out of the head unit, while only requiring access from one side of the conduit. The cooling fluid conduit inlet(s) and outlet(s) may be clustered together, for instance in their own minor sector or segment, or clustered with other outer ports, such as inject flow outer ports. Where inject flow outer ports are clustered based upon the region of the head unit their inner ports are located within, the cooling fluid conduit servicing that same region of the head unit may have its inlet and / or outlet located within the same cluster. Again, this may facilitate easier servicing.

[0036] Additionally, or alternatively, the head unit, when viewed from above, may comprise a central circular area which is generally free from outer ports and / or inner ports. The central circular may be coaxial with the longitudinal axis of the head unit. The inner port(s) and outer port(s) may all be located in a substantially annular portion of the head unit and / or adjacent the perimeter of the head unit.

[0037] In all aspects and embodiments of the invention, preferably the head unit is monolithic. For the purposes of the present invention, monolithic may 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 head unit may include components that are welded together, thereby effectively becoming a single, unitary component. The head unit may define the fluid flow contact surfaces of the effluent flow conduits and / or the inject fluid flow conduits of the head unit.

[0038] 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 purposesof 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 head unit.

[0039] 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 of the head unit in comparison with alternative materials. This may aid in serviceability of the head unit.

[0040] In some embodiments, a surface layer, or coating, 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 surface(s) defining the effluent flow conduit(s). Advantageously, this may improve the corrosion resistance of the effluent flow conduit(s).

[0041] 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. 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.

[0042] 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 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 arrangement may enable the inlet nozzle(s) to be easily removed from the head unit for maintenance.

[0043] In alternative embodiments, the head unit may define the nozzle configured to inject the effluent gas flow into the combustion chamber.

[0044] The head unit may further comprise effluent conduits extending from the outer surface to the inner surface of the head unit configured to direct effluent into the combustion chamber for treatment thereof. The effluent flow conduits may comprise the inner ports described herein, for instance for delivering fuel, nitrogen and / or oxygen, or the like, to the effluent flow before it enters the combustion chamber.

[0045] Thus, in a further aspect, the invention provides a head unit for capping a combustion chamber of an abatement system, the head unit comprising a plurality of inject flow conduits and a plurality of effluent flow conduits, wherein the inject flow conduits each comprise an inject-flow inlet ports, and, when viewed from above, the inject flow inlet ports are all located in a single minor sector of the head unit.

[0046] Preferably, said inject-flow inlet ports, and / or outer ports of the previous aspect, are located radially outward of the effluent flow conduits. Preferably, the head unit defines a fluidflow contact surface of the or each conduit, e.g. the inject flow conduits and / or the effluent flow conduits, and / or cooling flow conduits.

[0047] For the avoidance of doubt, the embodiments described herein before with regard the previous aspect may be combined mutatis mutandis with the present aspect.

[0048] In a further aspect, the present invention provides an abatement apparatus. 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 any preceding aspect. The head unit is arranged at the inlet of the combustion chamber and configured to direct an effluent gas flow into the combustion chamber. Preferably the abatement apparatus comprises a cabinet for housing theFigures

[0049] Preferred features of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:Figure 1 shows a perspective view of a head unit according to the present invention.Figure 2 shows a skeletonised perspective view of the head unit of Figure 1 .Figure 3 shows an alternative skeletonised view of the head unit of Figure 1 .Detailed Description

[0050] The invention provides a head unit for capping a combustion chamber of an abatement system. The head unit comprises an outer face and inner face, which inner face, in use, forms an internal surface of the combustion chamber. The head unit further defines a plurality of conduits, each conduit running from the outer face of the head unit to said inner face or to an effluent flow conduit. Each conduit has an outer port at or adjacent said outer face and an inner port at or adjacent said inner face or in an effluent flow conduit.

[0051] When the head unit is viewed from above, a subset of the outer ports is located in a minor sector of said head unit and at least a portion of said subset of said outer ports have their respective inner port(s) outside of said minor sector of said head unit.

[0052] The head unit for capping a combustion chamber of an abatement system may comprise a plurality of inject flow conduits and a plurality of effluent flow conduits, wherein the inject flow conduits each comprise an inject-flow inlet port, and, when viewed from above, the inject flow inlet ports are all located in a single minor sector of the head unit.

[0053] Turning to Figure 1 , what is shown is a generally cylindrical head unit referenced generally as 10. The head unit is for arrangement at an inlet of a combustion chamber of an abatement apparatus (not shown). When arranged at an inlet of a combustion chamber of an abatement apparatus, the head unit 10 defines a portion of the combustion chamber.

[0054] The head unit 10 comprises a head plate 12 configured to cap a combustion chamber (not shown).

[0055] The head unit 10 further comprises six effluent flow conduits 14a-14f for receiving incoming effluent flows from several sources, e.g. process tools. The effluent flows are received via an effluent inlet, such as 26, of each effluent conduit and exit via an effluent outlet, such as 34.

[0056] Each effluent flow conduit 14 has an effluent flow contact surface, such as 16, which is configured to convey an effluent flow (from an upstream process tool) towards thecombustion chamber of the abatement apparatus. Each effluent flow contact surface is defined by the head plate 12. In other words, the each effluent flow conduit 14 is an integral part of the head plate 12.

[0057] The head unit 10 of Figure 1 is substantially monolithic. In the head unit 10 of Figure 1 , the head unit 10 is monolithic with the exception of distinct nozzles (not shown) which, in use, are inserted in channels 36.

[0058] As shown better in Figure 2, the head unit 10 also comprises a plurality of inject flow conduits 18, 20, 22 associated with each effluent flow conduit 14. Each inject flow conduit terminates at an inject flow port, such as 24a-24c. In the embodiment of Figure 1 , the inject conduits terminating an inject flow ports 24a-24c are associated with effluent flow conduit 14c.

[0059] Each effluent flow conduit in Figure 1 has a fuel inject 18, an oxygen-based inject 20, and a nitrogen-based inject 22. Typically, the nitrogen-based inject 22 is configured, in use, to maintain a forward flow of the effluent gas flow.

[0060] Each of the inject flow conduits has an inject flow contact surface which is defined by the head plate 12. In other words, each of the inject flow conduits 18, 20, 22 is an integral part of the head plate 12. The inject flow conduits are therefore substantially internally routed within the head plate 12.

[0061] As shown in Figure 2, an inject flow port associated with an effluent flow conduit may be located in a different sector of the head unit 10 to the corresponding effluent flow conduit when the head unit is viewed from above. For example, effluent flow conduit 14c, and its associated inject flow outlet ports, are located outside of the minor sector of the head unit 10 comprising the inject flow outer ports 24a-c. Indeed, all of the inject flow outer ports of the head unit are located in a single minor sector, moreover a single segment of said minor sector.

[0062] As shown in Figure 1 , by each of the inject flow outer ports being located together, more space is provided at an upstream side of the head unit compared to known head units.

[0063] More specifically, the head plate 12 has a substantially planar portion 28. The planar portion 28 of the head plate 12 is typically configured to couple to a combustion chamber.Each inject flow conduit 18, 20, 22 is substantially internally routed within the planar portion 28 of the head plate 12.

[0064] Referring to Figure 2, it can be seen that each inject flow conduit 18, 20, 22 has a flow direction generally parallel to the transverse plane of the head unit. In other words, in use, an inject gas enters a said inject flow conduit via a corresponding inject flow port and the inject gas is conveyed substantially horizontally within the head plate 12 towards a corresponding effluent flow.

[0065] Each of the inject flow conduits 18, 20, 22 also includes one or more bends or curved portions. An inject flow conduit 18, 20, 22 may also include one or more axial bends.

[0066] Referring still to Figure 2, several of the inject flow conduits 18, 20, 22, are arranged substantially concentrically within the head plate 12.

[0067] In the head unit 10 of Figure 1 , each of the inject flow ports 24 is arranged at a bank (herein also referred to as a manifold) 32 of inject flow ports. The bank (manifold) 32 of inject flow ports is typically arranged such that each of the inject flow ports is presented to an engineer upon opening a cabinet in which the abatement apparatus is situated. The internal routing of the inject flow conduits facilitates the positioning of each inject flow port at the bank 32 thereof.

[0068] Figure 3 shows another head unit 10 in which inject flow ports 24 are paired and located within a minor segment or sector of the head unit 10, when the head unit 10 is viewed from above. There are three pairs of inject flow ports 24 which together form a bank of inject flow ports. The head unit 10 includes a combination of concentrically arranged inject flow conduits and non-concentrically arranged, e.g. point-to-point, inject flow conduits.

[0069] In the head units 10 of both Figures 1 and 2, and of Figure 3, one or more of the inject flow conduits 18, 20, 22 are typically arranged closer to the perimeter of the head unit 10 than the centre thereof. More space is therefore provided towards the centre of the head unit for other components, and / or for improved engineer access.

[0070] The head units 10 of Figures 1 and 2, and of Figure 3 are substantially symmetrically formed about a radial cross section which passes through the centre of the bank of inject flow ports, as illustrated by dashed line ‘A’ in Figure 3.

[0071] Referring back to Figure 1 , an outwardly facing surface 1 of the head plate 12 defines a pattern of hollows or depressions, such as 30, which each have a substantially hexagonal transverse cross section. The plurality of hollows have a substantially similar depth in Figure 1, although their depth may vary dependent on the corresponding arrangement of inject flow conduits within the head plate 12.

[0072] Typically, the head unit (10) may be manufactured using an additive manufacturing technique. For example, the head unit (10) may be manufactured by direct metal laser sintering.

[0073] It will be appreciated that various modifications may be made to the embodiments shown without departing from the spirit and scope of the invention as defined by the accompanying claims as interpreted under patent law.Key10 Head unit12 Head plate14 Effluent flow conduit16 Effluent flow contact surface18 Inject flow conduit20 Inject flow conduit22 Inject flow conduit24 Inject flow port26 Effluent inlet28 Planar portion30 Hollow32 Inject flow port bank34 Effluent outlet36 Channel

Claims

Claims1. A head unit for capping a combustion chamber of an abatement system, the head unit comprising an outer face and inner face, which inner face, in use, forms an internal surface of the combustion chamber, and the head unit further defining a plurality of conduits, each conduit running from said outer face, and each conduit having an outer port at or adjacent said outer face and an inner port at or adjacent said inner face or in a surface of an effluent flow conduit, wherein, when the head unit is viewed from above, a subset of the outer ports is located in a minor sector of said head unit and at least a portion of said subset of said outer ports have their respective inner port(s) outside of said minor sector of said head unit.

2. The head unit according to claim 1 wherein said portion of said subset of said outer ports having their respective inner port(s) outside said minor sector comprises two or more outer ports.

3. The head unit according to any preceding claim comprising outlet ports grouped within two or more independent outer port-containing minor sectors, each independent outer portcontaining minor sector comprising a separate subset of outer ports.

4. The head unit according to any preceding claim wherein the or each subset of the outer ports are configured to receive an inject flow.

5. The head unit according to any preceding claim wherein the or each outer portcontaining minor sector has a central angle of greater than about 15 degrees.

6. The head unit according to any preceding claim wherein the subset or subsets of outer ports are located on or adjacent an outer segment of the or each outer port-containing minor sector of said head unit.

7. The head unit according to any preceding claim wherein the or each inner port is an outlet of the conduit and / or the or each outer port is an inlet of the conduit.

8. The head unit according to any preceding claim wherein the head unit includes one or more cooling fluid conduits, preferably wherein an inlet and / or an outlet of the or each cooling fluid conduit is located on an outer face of said head unit, preferably within a, the or each outer port-containing minor sector.

9. The head unit according to any preceding claim wherein the head unit is monolithic.

10. The head unit according to any preceding claim wherein the head unit comprises a material selected from aluminium or stainless steel.11 . The head unit according to any preceding claim wherein the density of ports within the or each outer port-containing minor sector is higher than outside the or each outer portcontaining minor sector.

12. The head unit according to any preceding claim further comprising a plurality effluent flow conduits extending from the outer surface to the inner surface of the head unit configured to direct effluent into the combustion chamber for treatment thereof, preferably wherein each effluent flow conduit includes an inner port in a surface thereof.

13. A head unit for capping a combustion chamber of an abatement system, the head unit comprising a plurality of inject flow conduits and a plurality of effluent flow conduits, wherein the inject flow conduits each comprise an inject flow port, and, when viewed from above, the inject flow ports are all located in a single minor sector of the head unit, , preferably wherein the head unit (10) is according to any preceding claim.

14. The head unit according to claim 13 wherein said inject flow ports are located radially outward of the effluent flow conduits.

15. The head unit according to any preceding claims wherein the head unit defines a fluid- flow contact surface of the or each conduit.

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