Patent Application
20200030828
The present invention relates to a nozzle for an abatement apparatus and a method.
Abatement apparatus are known and are typically used for treating an effluent gas stream from a manufacturing processing tool used in, for example, the semiconductor or flat panel display manufacturing industry. During such manufacturing, residual perfluorinated compounds (PFCs) and other compounds exist 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 because they are known to have relatively high greenhouse activity.
Known abatement apparatus use combustion to remove the PFCs and other compounds from the effluent gas stream. Typically, the effluent gas stream is a nitrogen stream containing PFCs and other compounds. A fuel gas is mixed with the effluent gas stream and that gas stream mixture is conveyed into a combustion chamber that is laterally surrounded by the exit surface of a foraminous gas burner. Fuel gas and air are simultaneously supplied to the foraminous burner to affect flameless combustion at the exit surface, with the amount of air passing through the foraminous burner being sufficient to consume not only the fuel gas supply to the burner, but also all the combustibles in the gas stream mixture injected into the combustion chamber.
Although techniques exist for processing the effluent gas stream, they each have their own shortcomings. Accordingly, it is desired to provide an improved technique for processing an effluent gas stream.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.
According to a first aspect, there is provided a nozzle for abatement apparatus operable to treat an effluent stream from a processing tool, the nozzle comprising: a nozzle body defining a nozzle inlet operable to receive the effluent stream, a nozzle outlet, and a conduit extending between the nozzle inlet and the nozzle outlet and operable to convey the effluent stream in a direction of flow from the nozzle inlet to the nozzle outlet; and an effluent stream rotator configured to impart a rotational component to the effluent stream to rotate the effluent stream around the direction of flow. The first aspect recognises that a problem with some inlet nozzles is that the destructive rate efficiency of the effluent stream achieved using those nozzles may be lower than desired.
Accordingly, an abatement apparatus nozzle may be provided. The abatement apparatus may be one which treats an effluent stream provided by a processing tool. The nozzle may comprise a nozzle body or housing. The nozzle body may provide or define a nozzle inlet or aperture. The nozzle inlet may receive or be provided with the effluent stream. The nozzle body may also define or be provided with a nozzle outlet or aperture. The nozzle body may define or be provided with a conduit or tube which extends between or couples the nozzle inlet with the nozzle outlet. The conduit may convey or communicate the effluent stream from the nozzle inlet to the nozzle outlet. The movement of the effluent stream from the nozzle inlet to the nozzle outlet may define a direction of flow of the effluent stream through the nozzle body. The nozzle may also comprise an effluent stream rotator or spinner. The rotator may be configured or arranged to impart, effect or introduce a rotational or spinning component to the effluent stream. That rotational component may rotate the effluent stream around the direction of flow. In this way, the effluent stream is rotated as it passes through the nozzle body. The destruction rate efficiency achieved by an abatement apparatus when receiving such rotating effluent streams has been found to be significantly improved compared to non-rotating effluent streams.
In one embodiment, the effluent stream rotator is configured to rotate the effluent stream about a flow axis defined by the direction of flow. Accordingly, the effluent stream rotator may rotate the effluent stream circumferentially about an axis extending through the conduit. In other words, the rotation may occur within a plane which is transverse to the axis extending along the conduit.
In one embodiment, the effluent stream rotator is configured to rotate the effluent stream into a vortex. Accordingly, the rotator causes the effluent stream to form a vortex which extends from the nozzle outlet. The axis of the vortex may be generally aligned with the flow axis extending along the conduit.
In one embodiment, the effluent stream rotator comprises a protruding structure upstanding from a surface of the conduit. Accordingly, a protrusion or element may extend from a surface of the conduit which interacts with the effluent stream and imparts the rotation as it flows through the conduit.
In one embodiment, the protruding structure is elongate and extends along the surface of the conduit.
In one embodiment, the protruding structure is helical. Forming a helical structure such as a thread is a convenient and effective arrangement for rotating the effluent stream. Such a structure is also typically resistant to the gathering of debris or powder which may otherwise cause blockages within the conduit.
In one embodiment, the conduit has a radius R and the protruding structure has an upstanding height into the conduit of between around 1/16 R and 3/16 R, and typically ⅛ R.
In one embodiment, the protruding structure extends at least partially along the conduit. Accordingly, the protruding structure may be provided on any portion of the conduit.
In one embodiment, the nozzle comprises a plurality of the protruding structures. Accordingly, the structure may have discontinuities and/or multiple structures may be provided. It will be appreciated that the number of protruding structures and the degree to which they occupy the conduit will affect the amount by which the flow of the effluent stream is affected.
In one embodiment, the plurality of the protruding structures define a multi-start thread arrangement.
In one embodiment, the effluent stream rotator comprises at least one secondary inlet located to convey a fluid to impart the rotational component to the effluent stream. Accordingly, an inlet or aperture may be provided through which a fluid passes and interacts with the effluent stream. In particular, the momentum of the fluid may cause a partial change in the direction of flow of the effluent stream to cause it to rotate.
In one embodiment, the secondary inlet is orientated introduce the fluid with a tangential component within the conduit.
In one embodiment, the secondary inlet is orientated introduce the fluid tangentially with respect to the conduit.
In one embodiment, the secondary inlet is orientated introduce the fluid with a direction of flow component within the conduit.
In one embodiment, the nozzle comprises a plurality of the secondary inlets.
In one embodiment, the plurality of the secondary inlets are located circumferentially around the conduit.
In one embodiment, the fluid comprises at least one of the effluent stream and a secondary stream.
According to a second aspect, there is provided a method comprising: providing a nozzle for an abatement apparatus operable to treat an effluent stream from a processing tool, the nozzle comprising a nozzle body defining a nozzle inlet operable to receive the effluent stream, a nozzle outlet, and a conduit extending between the nozzle inlet and the nozzle outlet and operable to convey the effluent stream in a direction of flow from the nozzle inlet to the nozzle outlet; and imparting a rotational component to the effluent stream to rotate the effluent stream around the direction of flow using an effluent stream rotator.
In one embodiment, the imparting comprises rotating the effluent stream about a flow axis defined by the direction of flow.
In one embodiment, the imparting comprises rotating the effluent stream into a vortex.
In one embodiment, the method comprises providing a protruding structure upstanding from a surface of the conduit as the effluent stream rotator.
In one embodiment, the protruding structure is elongate and extends along the surface of the conduit.
In one embodiment, the protruding structure is helical.
In one embodiment, the conduit has a radius R and the protruding structure has an upstanding height into the conduit of between around 1/16 R and 3/16 R, and typically ⅛ R.
In one embodiment, the method comprises extending the protruding structure at least partially along the conduit.
In one embodiment, the method comprises providing a plurality of the protruding structures.
In one embodiment, the method comprises providing a multi-startthread arrangement as the plurality of the protruding structures.
In one embodiment, the method comprises providing at least one secondary inlet as the effluent stream rotator and locating the at least one secondary inlet to convey a fluid to impart the rotational component to the effluent stream.
In one embodiment, the method comprises orientating the secondary inlet introduce the fluid with a tangential component within the conduit.
In one embodiment, the method comprises orientating the secondary inlet to introduce the fluid tangentially with respect to the conduit.
In one embodiment, the method comprises orientating the secondary inlet introduce the fluid with a direction of flow component within the conduit.
In one embodiment, the method comprises providing a plurality of the secondary inlets.
In one embodiment, the method comprises locating the plurality of the secondary inlets circumferentially around the conduit.
In one embodiment, the fluid comprises at least one of the effluent stream and a secondary stream.
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.
Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.
The Summary is provided to introduce a selection of concepts in a simplified form that are further described in the Detail Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which:
Before discussing the embodiments in any more detail, first an overview will be provided. Embodiments provide an abatement apparatus nozzle. The nozzle has an inlet, an outlet and a conduit. The inlet receives an effluent stream, which flows through the conduit from the inlet to the outlet. The nozzle has a rotator which rotates the effluent stream within a plane which is transverse to the direction of flow. In particular, the effluent stream is typically rotated into a vortex, in which the effluent stream rotates about an axis line extending between the inlet and the outlet, along the conduit. Accordingly, the rotator rotates the effluent stream as it passes through the nozzle, which delivers a rotating effluent stream into the treatment chamber. In some embodiments, the rotator comprises a structure placed within the conduit which interacts with the effluent stream as it flows through the conduit, typically by providing a surface extending into the conduit which interacts with the flow of the effluent stream and causes it to rotate. Embodiments also provide a fluid which is injected into the conduit and the interaction between that fluid and the effluent stream causes the effluent stream to rotate.
The treatment chamber 14 has side walls defined by an exit surface 21 of a foraminous sleeve 20 in the form of a cylindrical tube. A plenum volume 22 is defined between an entry surface 23 of the foraminous sleeve 20 and a cylindrical outer shell 24. The cylindrical outer shell 24 is concentrically enclosed within an outer insulating sleeve 60 in order to reduce the outer surface temperature to safe levels should the temperature of the cylindrical outer shell 24 become raised due to, for example, stray heating. Additional, or alternatively, a cooler may be located within or against the outer shell in order to provide cooling.
A gas is introduced into the plenum volume 22 via an inlet nozzle (not shown). The gas may be air and a flammable gas mixture (such as a hydrocarbon, for example methane), or a blend of air and flammable gas mixture together with other species such as water vapour, CO2. The gas is introduced and passes from the entry surface 23 to the exit surface 21 of the foraminous sleeve 20 where it combusts to heat the treatment chamber 14.
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Results (1) show the destruction rate efficiency at different rates of effluent stream using an existing inlet nozzle arrangement which has a dog-leg portion, such as that illustrated in EP 2 989 387 A1.
Results (2) show the destruction rate efficiency for a straight nozzle, such as that illustrated in
Results (12C) show the DRE for the nozzle 12C. As can be seen, the DRE of such a nozzle improves compared to that of a straight nozzle with no thread on the inner surface.
Results (12A) show the DRE of the nozzle 12A. As can be seen, the DRE of nozzle 12A is improved compared to that of nozzle 12C.
Results (12B) show the performance of the nozzle 12B. As can be seen, the DRE matches or exceeds that of the existing nozzle and avoids the problems of powder or debris gathering in the dog-leg.
Accordingly, embodiments provide a modification to a straight through nozzle arrangement which enhances abatement performance. Embodiments seek to expand the useful range of operation of these nozzles to lower flow rates.
In embodiments, a nozzle is constructed from a heat and chemically-resistant metal alloy, for example ANC16. The nozzle is typically formed by a casting process, for example lost wax casting. In one embodiment, at least one helical vane, protruding from the inner wall of the nozzle extends at least partially in the direction of the flow axis. It is found that the abatement performance of a gas such as NF3 is very much improved by this feature. The improvement is significantly greater than that obtained by reducing the nozzle diameter to that of the narrowest dimension of the vane, indicating that a swirl is introduced into the gas by the vane, thereby improving performance. Embodiments deliberately induce a swirl in the incoming process gas. Variations include the pitch and number of starts of the helix, also the depth i.e. the protrusion of the helix into the gas stream. Such nozzles may be used with all radiant burner products, including induction-heated and gas-fired burners.
Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can he effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.
Although elements have been shown or described as separate embodiments above, portions of each embodiment may be combined with all or part of other embodiments described above.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are described as example forms of implementing the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1704853.9 | Mar 2017 | GB | national |
This application is a Section 371 National Stage Application of International Application No. PCT/GB2018/050744, filed Mar. 21, 2018, and published as WO 2018/178636 A1 on Oct. 4, 2018, the content of which is hereby incorporated by reference in its entirety and which claims priority of British Application No. 1704853.9, filed Mar. 27, 2017.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/GB2018/050744 | 3/21/2018 | WO | 00 |
