Inlet assembly for abatement assembly and method of delivering effluent to an abatement chamber

Abstract

An inlet assembly for an abatement apparatus is disclosed. The inlet assembly includes an effluent flow conduit configured to transport an effluent flow in a primary flow direction within the effluent flow conduit, an inlet nozzle fluidly coupled with the effluent flow conduit and configured to transport the effluent flow received from the effluent flow conduit to an abatement chamber of the abatement apparatus, and a baffle interposed between the effluent flow conduit and the inlet nozzle, the baffle shaped and configured to redirect the flow of the effluent flow from the effluent flow conduit into the inlet nozzle by inhibiting the flow of the effluent flow in the primary flow direction into the inlet nozzle. In this manner, the line-of-sight flow from the effluent flow conduit into the inlet nozzle is prevented by the baffle, and the effluent flow instead follows a non-line-of-sight or diverted path from the effluent flow conduit into the inlet nozzle, which increases the residence time within the inlet nozzle and helps provide more laminar flow into the abatement chamber, which improves the destruction rate efficiency (DRE).

Description

Technical Field

[0001] The field of the invention relates to inlet assemblies for emission abatement devices. Background Art

[0002] Emission abatement equipment is known and is commonly used to treat effluent gas streams from manufacturing process tools used in industries such as semiconductor or flat panel display manufacturing. During this manufacturing process, residual perfluorinated compounds (PFCs) and other compounds are present in the effluent gas stream pumped from the process tool. PFCs are difficult to remove from the effluent gas, and their release into the environment is undesirable due to their known relatively high greenhouse activity.

[0003] Known abatement equipment uses combustion to remove PFCs and other compounds from an outflowing gas stream. Typically, the outflowing gas stream is a nitrogen stream containing PFCs and other compounds. Fuel gas is mixed with the outflowing gas stream, and this gas stream mixture is delivered using an inlet assembly to an abatement chamber, such as a combustion chamber laterally surrounded by the outlet surface of a perforated gas burner. Fuel gas and air are supplied simultaneously to the perforated burner to achieve flameless combustion at the outlet surface. The amount of air passing through the perforated burner is sufficient to consume not only the fuel gas supplied to the burner but also all combustibles in the gas stream mixture injected into the combustion chamber.

[0004] While techniques exist for treating effluent gas streams, they each have their own drawbacks. It would therefore be desirable to provide an improved technique for treating effluent gas streams. Summary of the Invention

[0005] According to a first aspect, an inlet assembly for an abatement device is provided, comprising: an outflow conduit configured to convey an outflow flow along a main flow direction within the outflow conduit; an inlet nozzle fluidly coupled to the outflow conduit and configured to convey the outflow flow received from the outflow conduit to an abatement chamber of the abatement device; and a baffle interposed between the outflow conduit and the inlet nozzle, the baffle being shaped and configured to redirect the flow of the outflow flow from the outflow conduit into the inlet nozzle by suppressing the flow of the outflow flow into the inlet nozzle along the main flow direction.

[0006] A first aspect recognizes that a problem with existing inlet assemblies is that their performance may be lower than it could be. Specifically, the destruction rate efficiency (DRE) achieved using these inlet assemblies may not meet a desired level. This may be due to the outflow stream passing through the inlet assembly and entering the abatement chamber too quickly. Therefore, an inlet assembly is provided. The inlet assembly may be an abatement device inlet assembly. The inlet assembly may include an outflow conduit that conveys or provides the outflow stream. The outflow stream may generally travel or move within the outflow conduit in a flow direction. The inlet assembly may include an inlet nozzle. The inlet nozzle may be coupled to the outflow conduit. The inlet nozzle may convey or transfer the outflow stream received from the outflow conduit into the abatement chamber. The inlet assembly may include a baffle. The baffle may be interposed, located, or positioned between the outflow conduit and the inlet nozzle. The baffle may be shaped, constructed, arranged, or positioned to redirect or divert the flow of the outflow stream traveling from the outflow conduit and entering the inlet nozzle. The flow may be diverted by inhibiting, blocking, or preventing the outflow stream from flowing into the inlet nozzle along its primary flow direction. In this way, line-of-sight flow from the outflow flow conduit into the inlet nozzle is prevented by the baffle, and the outflow flow instead follows a non-line-of-sight or diverted path from the outflow flow conduit into the inlet nozzle, which increases the residence time within the inlet nozzle and helps provide more laminar flow into the abatement chamber, which improves DRE and can reduce fuel consumption.

[0007] The outflow flow may exit the outflow flow conduit in a main flow direction.

[0008] The baffle may be shaped and configured to redirect the flow of the outgoing stream away from the main flow direction into the inlet nozzle.

[0009] The baffles may be shaped and configured to promote turbulence in the outflow upstream of the inlet nozzle. Promoting turbulence may improve mixing of the outflow, which may improve DRE.

[0010] The baffles may be shaped and configured to promote laminar flow of the outflow stream into the inlet nozzle. Thus, when the outflow stream flows into the nozzle, the baffles may help restore laminar or uniform flow of the outflow stream, which in turn improves DRE.

[0011] The baffle may be shaped and configured to promote uniform axial flow velocity within the inlet nozzle. By providing a uniform axial flow velocity within the baffle, the laminar or uniform flow of the outflow is improved, which again improves the DRE.

[0012] The baffle can be shaped and configured to suppress an increase in the axial flow velocity within the inlet nozzle near the outflow conduit and suppress a decrease in the axial flow velocity within the inlet nozzle away from the outflow conduit, thereby achieving a uniform axial flow velocity within the inlet nozzle. Thus, the baffle can reduce the axial flow velocity in the area closest to the outflow conduit and increase the axial flow velocity in the area farthest from the outflow conduit, thereby achieving a more uniform flow velocity within the nozzle and helping to balance the flow to improve DRE.

[0013] The baffle may include a baffle conduit positioned in the plenum configured to receive the outflow flow from the outflow flow conduit, the baffle conduit defining at least one orifice positioned for fluid communication between the plenum and the inlet nozzle.

[0014] The baffle conduit may extend in an axial direction in coaxial alignment with the inlet nozzle.

[0015] At least one orifice may be positioned remotely from a location on the baffle duct aligned with an incident outflow stream traveling in a primary flow direction. Thus, the orifice may be offset, remotely positioned, non-incident, or misaligned with the primary flow direction of the outflow stream in order to reduce line-of-sight flow from the baffle duct to the inlet nozzle to improve DRE.

[0016] The at least one aperture may be located toward at least one axial end of the baffle conduit.

[0017] The inlet assembly may include a plurality of orifices.

[0018] At least some of the plurality of apertures may be positioned circumferentially around the baffle conduit.

[0019] The cross-sectional area of ​​the orifice near the outflow conduit can be smaller than the cross-sectional area of ​​the orifice farther from the outflow conduit. This helps reduce the flow velocity closest to the outflow conduit and promotes flow velocity farther from the outflow conduit, thereby balancing the flow within the baffle and improving uniform flow within the inlet nozzle and improving DRE.

[0020] The cross-sectional area of ​​the plurality of apertures may match the cross-sectional area of ​​the baffle conduit.

[0021] The baffle conduit may be shaped to redirect the flow of the outflow stream in the plenum in a direction transverse to the main flow direction.

[0022] The orifices may be shaped to redirect the flow of the outflow stream to deliver the outflow stream radially into the baffle conduit.

[0023] The baffle conduit may be shaped to redirect the flow of the outflow stream to convey the outflow stream in an axial direction along the baffle conduit into the inlet nozzle.

[0024] The outflow flow conduit may be shaped and configured to deliver the outflow flow in a primary flow direction transverse to the axial direction.

[0025] The outflow flow conduit may follow a tortuous path.

[0026] The baffle duct and / or the inlet nozzle may include a helical structure configured to impart a circumferential rotational component to the outflow flow.

[0027] The baffle duct and / or the inlet nozzle may include a coaxial lance positioned therein.

[0028] The helical structure may be configured to extend beyond the lance in an axial direction.

[0029] The lance may not extend in an axial direction beyond the opening of an inlet nozzle which may be positioned within the abatement chamber.

[0030] The baffle duct may extend in the axial direction by at least 5 times its inner diameter. This helps provide sufficient distance to restore laminar flow.

[0031] According to a second aspect, there is provided an abatement apparatus comprising the inlet assembly of the first aspect and an abatement chamber.

[0032] According to a third aspect, a method is provided, comprising: conveying an outflow flow in an outflow flow conduit along a main flow direction; connecting an inlet nozzle to the outflow flow conduit to convey the outflow flow received from the outflow flow conduit to an abatement chamber of an abatement device; and placing a baffle between the outflow flow conduit and the inlet nozzle to redirect the flow of the outflow flow from the outflow flow conduit into the inlet nozzle by suppressing the flow of the outflow flow into the inlet nozzle along the main flow direction.

[0033] The outflow flow may exit the outflow flow conduit in a main flow direction.

[0034] The method may include redirecting the flow of the outflow stream away from the main flow direction into the inlet nozzle.

[0035] The method may include promoting turbulence in the outflow stream upstream of the inlet nozzle.

[0036] The method may include promoting laminar flow of the outflow into the inlet nozzle.

[0037] The method may include promoting a uniform axial flow velocity within the inlet nozzle.

[0038] The method may include suppressing an increase in axial flow velocity within the inlet nozzle proximate to the outflow flow conduit and suppressing a decrease in axial flow velocity within the inlet nozzle away from the outflow flow conduit to achieve a uniform axial flow velocity within the inlet nozzle.

[0039] The method may include positioning a baffle conduit of the baffle in the plenum configured to receive the outflow flow from the outflow flow conduit, the baffle conduit defining at least one orifice positioned for fluid communication between the plenum and the inlet nozzle.

[0040] The baffle conduit may extend in an axial direction in coaxial alignment with the inlet nozzle.

[0041] The method may include positioning at least one orifice remote from a location on the baffle conduit aligned with an incident outflow stream traveling in the primary flow direction.

[0042] The method may include positioning at least one aperture toward at least one axial end of the baffle conduit.

[0043] Multiple orifices may be provided.

[0044] The method may include positioning at least some of the plurality of apertures circumferentially around the baffle conduit.

[0045] The method may include providing a cross-sectional area of ​​the orifice proximate the outflow flow conduit to be smaller than a cross-sectional area of ​​the orifice distal to the outflow flow conduit.

[0046] The method may include matching a cross-sectional area of ​​the plurality of apertures to a cross-sectional area of ​​the baffle conduit.

[0047] The method may include redirecting the flow of the outflow stream in the plenum into a direction transverse to the main flow direction.

[0048] The method may include redirecting the flow of the effluent stream to deliver the effluent stream radially into the baffle conduit.

[0049] The method may include redirecting the flow of the effluent stream to deliver the effluent stream in an axial direction along the baffle conduit into the inlet nozzle.

[0050] The method may include delivering the outflow stream in a primary flow direction transverse to the axial direction.

[0051] The outflow flow conduit may follow a tortuous path.

[0052] The method may include imparting a circumferential rotational component to the outflow flow.

[0053] The method may include positioning a coaxial lance within at least one of the baffle conduit and the inlet nozzle.

[0054] The method may include extending the helical structure in an axial direction beyond the lance.

[0055] The method may include preventing the lance from extending in an axial direction beyond an opening of an inlet nozzle positionable within the abatement chamber.

[0056] The method may include extending the baffle conduit in an axial direction a distance of at least 5 times its inner diameter.

[0057] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

[0058] Where a device feature is described as being operable to provide a functionality, it will be appreciated that this includes device features that provide that functionality or that are adapted or configured to provide that functionality. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The embodiments of the present invention will now be further described with reference to the accompanying drawings, in which:

[0060] Figure 1 An inlet assembly for an abatement device is shown according to one embodiment;

[0061] Figure 2 is a computational fluid dynamics analysis showing the velocities experienced within the inlet assembly;

[0062] Figure 3 shows a contour line of fuel mass fraction on a plane located downstream of a fuel injection gun;

[0063] Figure 4 is a graph showing the difference in DRE and NOx with and without the use of baffles;

[0064] Figure 5 The performance of abatement equipment with one, two, and six inlet assemblies feeding the abatement chamber is demonstrated;

[0065] Figure 6 Baffles with apertures located at different positions are shown;

[0066] Figure 7 is a graph showing the generation of DRE, NOx, and CO as the aperture orifice moves down the baffle;

[0067] Figure 8A and Figure 8B The positions of the standard length fuel lance and the longest length fuel lance are shown respectively;

[0068] Figure 9 is a graph showing DRE, CO and NOx performance using different fuel lance lengths;

[0069] Figure 10 is a graph showing DRE, CO and NOx performance using different spring lengths;

[0070] Figure 11 is a CFD comparison of the inlet assembly with and without the baffle; and

[0071] Figure 12 An inlet assembly for an abatement device is shown according to one embodiment. DETAILED DESCRIPTION

[0072] Before discussing the embodiments in more detail, an overview will first be provided. The embodiments provide an arrangement that helps facilitate mixing between a gas (e.g., fuel, oxidizer, or another compound) and an outflow stream, and increases the residence time of the mixed gas and outflow stream before entering an abatement chamber, which increases DRE and can reduce fuel consumption. This is achieved by inhibiting the outflow stream from following a flow path that limits the amount of mixing that occurs and reduces residence time, and instead causing the outflow stream to follow a flow path that facilitates such mixing and increases residence time. Specifically, structure is positioned within the outflow flow to prevent the outflow stream from following a direct line-of-sight path from the outflow conduit into the inlet nozzle. This direct line-of-sight path reduces mixing and residence time, which, in turn, reduces destruction rate efficiency (DRE). The outflow stream is sometimes delivered to the inlet nozzle at an angle, which causes the outflow stream to flow unevenly within the inlet nozzle, with greater flow and less mixing occurring in the portion of the nozzle near the inlet where the outflow stream is provided. This results in uneven mixing of the outflow stream and gas, which leads to a less-than-ideal DRE. While different configurations are possible, in an arrangement where an inlet nozzle is used to deliver the mixed effluent flow and gas to the abatement chamber, a baffle can be positioned to intersect the flow of the effluent flow when delivered to the inlet nozzle. The baffle can have one or more orifices therein. Thus, the effluent flow is diverted by the baffle. The effluent flow then flows through these orifices and enters the inlet nozzle. The baffle can then reestablish a uniform flow of the effluent flow within the nozzle for mixing with the fuel.

[0073] Entry component.

[0074] Figure 1 An inlet assembly 10 for an emissions abatement device is shown, according to one embodiment. The inlet assembly 10 has an inlet nozzle 20 comprising an elongated cylindrical conduit having a fuel lance 30 coaxially positioned therein. A concentrically positioned coil spring 40 is positioned between the outer surface of the fuel lance 30 and the inner surface of the inlet nozzle 20. In this example, the fuel lance 30 can be provided in three different lengths, A, B, or C. Another concentrically positioned lance 55 is provided that delivers a supplied gas, such as fuel or oxidant, to a port 65. A baffle 50 is provided in an upper portion of the inlet nozzle 20. The baffle 50 comprises a cylindrical tube having a plurality of orifices 60 formed through its wall. The wall of the inlet nozzle 20 has an orifice 70 that receives an outflow conduit 80. The outflow conduit is provided with an oxygen injector 90 that is arranged to inject oxygen into the outflow conduit 80.

[0075] In operation, outflow stream 100 is delivered into outflow conduit 80. When activated, oxygen injector 90 delivers oxygen into outflow stream 100 as outflow stream 100 passes through outflow conduit 80 toward orifice 70. Baffle 50 presents a cylindrical surface to the incident outflow stream 100 delivered through orifice 70. Baffle 50 seals the upper portion of inlet nozzle 20, and the only way outflow stream 100 can advance through inlet nozzle 20 is through orifice 60. Therefore, outflow stream 100 passes through orifice 70 and enters chamber 110 defined by the outer surface of baffle 50 and the inner surface of the upper portion of inlet nozzle 20. As a result, the primary direction of flow of the outflow stream is diverted toward orifice 60. This redirection of flow causes turbulence that helps mix oxygen into outflow stream 100. An annular chamber 120 is defined between the inner surface of baffle 50 and the outer surface of fuel injector 30. The annular chamber 120 redirects the flow of the outflow stream 100 along the elongated axis of the annular chamber 120. This flow redirection causes turbulence that helps mix oxygen into the outflow stream 100. As the outflow stream 100 travels along the elongated axis of the annular chamber 120, generally laminar flow is restored. As the outflow stream 100 passes through the end of the fuel lance 30, mixing begins between the fuel 130 delivered via the fuel lance 30 and the outflow stream 100. Mixing continues until the mixed fuel and outflow stream 140 exit the inlet nozzle 20 and enter an abatement chamber (not shown) concentrically surrounded by gas delivered from the lance 55. To facilitate mixing of the mixed fuel and outflow stream 140 and improve its stability, a spring 40 imparts a rotational component to the mixed fuel and outflow stream 140 as it passes along the annular chamber 120.

[0076] If you can Figure 1 As will be appreciated, if baffle 50 is absent, outflow stream 100 delivered through orifice 70 would enter inlet nozzle 20 at an oblique angle and, when in position A, travel in an uneven manner past the end of fuel lance 30, resulting in uneven mixing and suboptimal DRE. In contrast, with baffle 50 present, outflow stream 100 travels evenly along annular chamber 120, allowing fuel to be evenly distributed (typically by diffusion) into the annular column of outflow stream 100 passing through annular chamber 120. The presence of this even fuel distribution contributes to improved DRE. As described above, the arrangement of outflow stream conduit, orifice 70, and baffle 50 provides improved DRE by primarily removing line-of-sight airflow entering inlet nozzle 20. This arrangement forces the primary airflow to be evenly distributed around the lance fuel, resulting in stable, consistent, and repeatable DRE and NOx readings.

[0077] speed.

[0078] Figure 2 is a computational fluid dynamics analysis showing the velocities experienced within the inlet assembly 10 . Figure 2A shows an arrangement without baffle 50, while Figure 2 B shows an arrangement with a baffle 50. As can be seen in the figure, Figure 2 In the arrangement of A, the velocity of the outflow stream as it enters the inlet nozzle 20 is relatively low, and the flow is biased toward the lower portion of the orifice 70 near the fuel injection gun 30. However, as Figure 2 As can be seen in FIG. 2B , pre-reaction mixing is improved because the baffle 50 helps provide uniform distribution of the outflow stream 100 within the inlet nozzle 20 , allowing the outflow stream to flow smoothly through the inlet nozzle 20 , and helps mix the fuel with the outflow stream, where the mixed fuel and outflow stream 140 have a longer residence time before entering the abatement chamber. The presence of the baffle 50 imparts a higher velocity to the outflow stream 100 , forcing the outflow stream 100 upward onto a smaller surface area and thereby increasing its velocity, which can help mix the fuel 130 with the outflow stream 100 .

[0079] mix.

[0080] Figure 3 The contour line of the fuel mass fraction at position A on a plane downstream of the fuel injection gun is shown. Figure 3 A shows the mass fraction in the absence of the baffle 50, and Figure 3 B shows the mass fraction in the presence of the baffle 50. As can be seen, fuel mixing is significantly improved in the arrangement with the baffle 50. Figure 3 In A, since the flow is inclined from the outflow flow conduit 80 into the inlet nozzle 20, the maximum fuel flow is concentrated at the area below the circled area, and therefore the mass fraction at this location is high. Figure 3 In B, the flow is traveling in a straight line in a downward direction, and therefore the flow is distributed across the plane, and the mass fraction is more uniform.

[0081] Figure 4 is a graph showing the difference in DRE and NOx with increasing oxygen flow with (line 1 showing DRE and line 3 showing NOx) and without (line 2 showing DRE and line 4 showing NOx) the baffles 50. As can be seen, the performance with the baffles 50 produces 15 ppm NOx at 95% DRE, compared to 23 ppm NOx produced at 95% DRE without the baffles.

[0082] Figure 5 The performance of abatement apparatus having one, two and six inlet assemblies 10 supplying increased oxygen flow to the abatement chamber is demonstrated. As can be seen, they each achieve consistent performance. Figure 6 A baffle 50 is shown with apertures located at different positions designated positions 1, 2, 3, 4 and 5.

[0083] like Figure 7 As can be seen in the figure, the aperture 70 is shown as it moves downward along the baffle 50 (at Figure 6 1, 2, 3, 4, and 5) in the graphs of DRE, NOx, and CO produced when the effluent 100 is at positions 1, 2, 3, 4, and 5 shown in FIG. , the CF4 DRE decreases as a result of the effluent stream 100 entering the line-of-sight region of the inlet nozzle 20 from the effluent flow conduit 80. As the orifice 70 continues downward, the effluent stream 100 leaves this region and the CF4 DRE returns to its normal performance. Therefore, it is important that the baffle 50 removes the line-of-sight flow from the effluent flow conduit 80 into the inlet nozzle 20. Other variations of the baffle 50, which forces the effluent stream 100 to sweep around the baffle 50 into the plenum 110 and upward or downward into the annular chamber 120, significantly improve emissions reduction performance.

[0084] Figure 8A and 8B A standard length fuel lance 30 is shown ( Figure 8A ) and the longest length of the fuel injection gun 30 ( Figure 8B ) and as above Figure 1 A spring 40 of appropriate size is provided.

[0085] Figure 9 is a graph showing DRE, CO and NOx performance at different fuel lance 30 lengths when operating with 9 SLM lance fuel, 2.5 SLM coaxial fuel, 15 SLM O2 and 26 LPM CDA. Figure 9 As can be seen in FIG, there is a clear trend that as the length of the fuel lance 30 increases, the DRE increases, and therefore it is preferred to incorporate a short fuel lance 30. The short fuel lance 30 gives the fuel and mixed fuel and outflow stream 140 increased residence time within the annular chamber 120, and the distance of the lance fuel from the coaxial flame is important for CF4 DRE. In addition, Figure 2 The analysis shown in shows that the lance fuel velocity is very disruptive, with the shortest fuel lance 30 allowing the lance fuel to interact with the mixed fuel and outflow stream 140, with the added benefit of residence time to smooth the flow, creating more laminar flow in the coaxial flame.

[0086] Figure 10 is a graph showing DRE, CO, and NOx performance for different spring 40 lengths (with the shortest fuel lance 30 installed), with lance fuel at 9 SLM, coaxial fuel at 2.5 SLM, O2 at 15 SLM, and CDA at 26 LPM. From the data shown, it appears that as the length of the spring 40 increases, the more turbulent airflow interacts with the vortex effect within the annular chamber 120 (as shown in FIG. Figure 11), resulting in increased mixing with oxygen from available CDA and thus lower NOx and CO emissions.

[0087] Figure 11 (It is with ( Figure 11 B) and no ( Figure 11 A) CFD comparison of the inlet assembly 10 with the baffle 50 also shows that the mixed fuel and outflow stream 140 have increased swirl as they exit the inlet nozzle 20 due to the increased inertia created by the baffle 50 .

[0088] Thus, as can be seen, the swept effluent flow conduit 80 and the baffle 50 control the gas path of the effluent flow 100 into the abatement chamber.

[0089] This arrangement addresses the need for improved CF4 DRE, and thus the distribution of the effluent flow around the fuel lance 30, in turn, helps mix the lance fuel with the incoming process gas (CF4, O2, and typically 50 slm of N2). The swept effluent flow conduit 80 removes the process gas bias, helps better mix the lance fuel and incoming process gas, and allows the resulting mixture to have a longer residence time before entering the coaxial flame.

[0090] Figure 12 An inlet assembly 10' for an abatement device according to one embodiment is shown. The arrangement is similar to that of reference Figure 1 The arrangement described above is different from the one described above, but the outflow stream 100' is delivered axially. The inlet assembly 10' has an inlet nozzle 20' comprising an elongated cylindrical conduit having a fuel lance 30' coaxially positioned therein. A concentrically positioned coil spring (not shown) may be positioned between the outer surface of the fuel lance 30 and the inner surface of the inlet nozzle 20. As described above, the fuel lance 30' may have different lengths. Another concentrically positioned lance 55' is provided that delivers a gas (such as fuel or oxidizer). A baffle 50' is provided in the upper portion of the inlet nozzle 20'. The baffle 50' comprises a cylindrical tube having a plurality of orifices 60' formed through its wall. The outflow conduit 80' receives the outflow stream 100' and is located upstream of the feed structure 150' in the outflow conduit 80'. The feed structure 150' delivers fuel 130' to the fuel lance 30' and has an orifice 75' to allow the outflow stream 100' to be delivered from the outflow flow conduit 80' to the plenum surrounding the baffle 50'.

[0091] During operation, outflow stream 100' is delivered to outflow conduit 80'. Upon startup, an oxygen injector (not shown) delivers oxygen to outflow stream 100' as it passes through outflow conduit 80' toward feed structure 150'. Outflow stream 100' passes through orifice 75' and undergoes multiple changes of direction, as the only way outflow stream 100' can proceed through inlet nozzle 20' is via orifice 60'. Consequently, the primary direction of flow of outflow stream 100' is diverted toward orifice 60'. This redirection of flow creates turbulence that helps mix oxygen into outflow stream 100'. An annular chamber 120' is defined between the inner surface of baffle 50' and the outer surface of fuel lance 30'. Annular chamber 120' redirects the flow of outflow stream 100' along the elongated axis of annular chamber 120'. This redirection of flow creates turbulence that helps mix oxygen into outflow stream 100'. As outflow stream 100' travels along the elongated axis of annular chamber 120', generally laminar flow is restored. As outflow stream 100' passes the end of fuel lance 30', mixing begins between fuel 130' delivered via fuel lance 30' and outflow stream 100'. Mixing continues until the mixed fuel and outflow stream 140' exit inlet nozzle 20' and enter an abatement chamber (not shown) concentrically surrounded by gas delivered from lance 55'. To facilitate mixing of the mixed fuel and outflow stream 140' and improve its stability, a spring may impart a rotational component to the mixed fuel and outflow stream 140' as it passes along annular chamber 120'. Although exemplary embodiments of the present invention have been disclosed herein in detail with reference to the accompanying drawings, it should be understood that the invention is not limited to the precise embodiments and that various changes and modifications may be implemented therein by those skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

[0092] List of reference numerals:

[0093] Inlet assembly 10; 10'

[0094] Inlet nozzle 20; 20'

[0095] Fuel injection gun 30; 30'

[0096] Spring 40

[0097] Baffle 50; 50'

[0098] Spray gun 55; 55'

[0099] Orifice 60; 60'; 70; 75'

[0100] Port 65

[0101] Outflow conduit 80; 80'

[0102] Oxygen Injector 90

[0103] outflow100;100'

[0104] Warehouse 110

[0105] Annular chamber 120; 120'

[0106] Fuel 130; 130'

[0107] Mixed fuel and outflow stream 140; 140'

[0108] Feed structure 150'.

Claims

1. An inlet assembly for an emission reduction device, comprising: an outflow flow conduit configured to convey an outflow flow in a primary flow direction within the outflow flow conduit; an inlet nozzle fluidly coupled to the outflow flow conduit and configured to deliver the outflow flow received from the outflow flow conduit to an abatement chamber of the abatement device; as well as a baffle interposed between the outflow flow conduit and the inlet nozzle, the baffle being shaped and configured to redirect the flow of the outflow flow from the outflow flow conduit into the inlet nozzle by inhibiting the flow of the outflow flow into the inlet nozzle along the primary flow direction, The baffle (50, 50') comprises a cylindrical tube having at least one orifice (60, 60') formed through its wall, the at least one orifice (60, 60') being positioned away from a position on the baffle in alignment with an incident outflow stream (100) travelling in the main flow direction, whereby the outflow stream (100) passes through the hole (70) of the inlet nozzle into a chamber (110) defined by the outer surface of the baffle and the inner surface of the upper portion of the inlet nozzle, the outflow stream thereby being turned towards the at least one orifice (60, 60') and entering, via the at least one orifice (60, 60'), an annular chamber (120, 120') defined between the inner surface of the baffle and the outer surface of the fuel lance, thereby causing turbulence that aids in mixing oxygen into the outflow stream. 2 . The inlet assembly of claim 1 , wherein the baffle is shaped and configured to redirect the flow of the outflow stream away from the primary flow direction into the inlet nozzle. 3 . The inlet assembly of claim 1 , wherein the baffle is shaped and configured to promote laminar flow of the outflow stream into the inlet nozzle.

4. The inlet assembly of any one of claims 1 to 3, wherein the baffle is shaped and configured to promote uniform axial flow velocity within the inlet nozzle.

5. The inlet assembly of claim 4 , wherein the baffle is shaped and configured to suppress an increase in the axial flow velocity within the inlet nozzle near the outflow flow conduit and to suppress a decrease in the axial flow velocity within the inlet nozzle away from the outflow flow conduit to obtain the uniform axial flow velocity within the inlet nozzle.

6. The inlet assembly of any one of claims 1 to 3, wherein the at least one aperture is located towards at least one axial end of the baffle conduit.

7. The inlet assembly of any one of claims 1 to 3, comprising a plurality of said apertures.

8. The inlet assembly of any one of claims 1 to 3, wherein a cross-sectional area of ​​an orifice proximal to the outflow flow conduit is smaller than a cross-sectional area of ​​an orifice distal to the outflow flow conduit.

9. The inlet assembly of any one of claims 1 to 3, wherein the baffle conduit is shaped to redirect the flow of the outflow stream in the plenum in a direction transverse to the main flow direction.

10. The inlet assembly of any one of claims 1 to 3, wherein the orifice is shaped to redirect the flow of the outflow stream to deliver the outflow stream radially into the baffle conduit.

11. The inlet assembly of any one of claims 1 to 3, wherein the outflow flow conduit is shaped and configured to deliver the outflow flow in the primary flow direction transverse to an axial direction.

12. The inlet assembly of any one of claims 1 to 3, wherein the outflow flow conduit follows a tortuous path.

13. The inlet assembly of any one of claims 1 to 3, wherein at least one of the baffle conduit and the inlet nozzle comprises a coaxial lance positioned therein.

14. The inlet assembly of claim 13, wherein the at least one of the baffle conduit and the inlet nozzle further comprises a helical structure configured to impart a circumferential rotational component to the outflow stream, the helical structure configured to extend in an axial direction beyond the lance.

15. The inlet assembly of any one of claims 1 to 3, wherein the baffle conduit extends in an axial direction by at least 5 times its inner diameter.

16. An abatement apparatus comprising an inlet assembly according to any preceding claim and the abatement chamber.

17. A method of introducing turbulence using the inlet assembly according to any one of claims 1 to 15, comprising: conveying the outflow flow in the outflow flow conduit in a main flow direction; coupling an inlet nozzle to the effluent flow conduit to deliver the effluent flow received from the effluent flow conduit to an abatement chamber of the abatement device; as well as A baffle is interposed between the outflow flow conduit and the inlet nozzle to redirect the flow of the outflow flow from the outflow flow conduit into the inlet nozzle by inhibiting the flow of the outflow flow into the inlet nozzle along the primary flow direction.

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