Gas treatment apparatus

Abstract

A gas treatment includes: a gas scrubber chamber operable to receive an effluent gas stream originating from a manufacturing process tool to be scrubbed therewithin to provide a scrubbed gas stream; and an electrostatic precipitation chamber operable to receive the scrubbed gas stream to be treated therewithin to provide a treated gas stream, one of the gas scrubber chamber and the electrostatic precipitation chamber defining a first chamber and another of the gas scrubber chamber and the electrostatic precipitation chamber defining a second chamber, the first chamber being configured to surround the second chamber. In this way, the first chamber and the second chamber can share the same volume.

Claims

1. A gas treatment apparatus, comprising: a gas scrubber chamber operable to receive an effluent gas stream originating from a manufacturing process tool to be scrubbed therewithin to provide a scrubbed gas stream; and an electrostatic precipitation chamber operable to receive said scrubbed gas stream to be treated therewithin to provide a treated gas stream, said electrostatic precipitation chamber defining a first chamber and said gas scrubber chamber defining a second chamber, said first chamber being configured to surround said second chamber wherein said first chamber and said second chamber share a common wall, an inner surface of said common wall defining an outer wall of said second chamber and an outer surface of said common wall defining an inner wall of said first chamber; said second chamber comprising an elongate chamber defined by said inner surface of said common wall and said first chamber comprising an elongate annular chamber defined by said outer surface of said common wall and an inner surface of an enclosing wall; wherein said electrostatic precipitation chamber comprises an elongate annular electrode structure located between said outer surface of said common wall and said inner surface of said enclosing wall, and outlets for ejecting liquid to provide a circumferentially flowing liquid curtain along both said outer surface of said common wall and said inner surface of said enclosing wall; wherein said gas scrubbing chamber comprises a header tank at least partially defining said gas scrubbing chamber and comprising a sieve plate, wherein a fluid path extends from said header tank to the outlets of the electrostatic precipitation chamber to provide the liquid curtain along the outer surface of the common wall; wherein said gas scrubbing chamber comprises an effluent gas stream inlet for receiving said effluent gas stream and a conduit to convey said scrubbed gas stream to an inlet of said electrostatic precipitation chamber located away from a suspension structure for said elongate annular electrode structure, said electrostatic precipitation chamber comprising a treated gas stream outlet for providing treated gas stream, said effluent gas stream inlet and said treated gas stream outlet being positioned to cause gas flow along an axial length of both said gas scrubbing chamber and said electrostatic precipitation chamber.

2. The apparatus of claim 1, wherein said elongate annular electrode structure extends axially along said electrostatic precipitation chamber.

3. The apparatus of claim 1, wherein said elongate annular electrode structure is located a constant distance between said outer surface of said common wall and said inner surface of said enclosing wall.

4. The apparatus of claim 1, wherein said elongate annular electrode structure comprises discharge points extending towards said outer surface of said common wall and said inner surface of said enclosing wall.

5. The apparatus of claim 4, wherein a number of discharge points extend toward the outer surface of said common wall and a number of discharge points extend toward the inner surface of said enclosing wall, the outer surface of the common wall has an area and the inner surface of the enclosing wall has an area and wherein a ratio of the number of said discharge points extending towards said outer surface of said common wall over the number of said discharge points extending towards said inner surface of said enclosing wall is proportional to a ratio of the area of said outer surface of said common wall and the area of said inner surface of said enclosing wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows an external view and a section through the gas treatment apparatus which illustrate the flow of an effluent gas through the apparatus according to one embodiment;

(3) FIG. 2 is an exploded view showing some components of the gas treatment apparatus;

(4) FIG. 3 is a section view through the gas treatment apparatus;

(5) FIG. 4 shows the arrangement of the sieve plate in more detail;

(6) FIG. 5 shows the arrangement of the structure providing inner weir;

(7) FIG. 6 illustrates the arrangement of the structure providing the outer weir;

(8) FIG. 7 shows the electrode structure attachment arrangement in more detail;

(9) FIG. 8 shows the arrangement of the electrode structure in more detail;

(10) FIG. 9 shows the arrangement of the inner wall and the outer wall in more detail;

(11) FIG. 10 shows the arrangement of the gas inlet and the sump in more detail;

(12) FIG. 11 illustrates the fluid feed provided to feed the sieve plate; and

(13) FIG. 12 shows an alternative embodiment of the outer wall which has a tapered or conical floor section.

DESCRIPTION OF THE EMBODIMENTS

(14) Overview

(15) Before discussing the embodiments in any more detail, first an overview will be provided. Embodiments provide an arrangement where both a gas scrubbing chamber and an electrostatic precipitation chamber are fluidly connected in series but are concentrically arranged such that one is provided within the other. In other words, one of the chambers surrounds the other in a nested configuration to provide a compact arrangement. By controlling the configuration of the inlets and outlets to the two chambers, it is possible to extend the flow distance within the chambers to be around double the length of the apparatus. Also, by utilising additional conduits it is possible to extend the flow distance and entry points to the chambers in order to help reduce the build-up of problematic residues. This approach provides for a more compact apparatus with a significantly reduced part count since the outer chamber is at least partially defined by its retained inner chamber.

(16) Example Arrangement and Gas Flow

(17) FIGS. 1 to 3 illustrate the arrangement of a gas treatment apparatus, generally 10, according to one embodiment. FIG. 1 shows an external view and a section through the gas treatment apparatus 10 which illustrate the flow of an effluent gas through the apparatus. FIG. 2 is an exploded view showing some components of the gas treatment apparatus 10. FIG. 3 is a section view through the gas treatment apparatus 10.

(18) In overview, the gas treatment apparatus 10 comprises an elongate cylindrical gas scrubber chamber 20 which is filled with packing materials (not shown). The gas scrubber chamber 20 comprises inlets 30 which receive the effluent gas to be processed and which flows in the direction A to B, advancing through the packing material towards a sieve plate 40. As will be explained in more detail below, the sieve plate 40 provides a fluid which flows within the gas scrubber chamber 20, through the packing material and through a sieve floor 50 back to a sump (not shown).

(19) Although in other embodiments it would be possible to provide a configuration where the effluent gas having passed through the scrubbing chamber 20 could exit the scrubbing chamber 20 in the vicinity of the sieve plate 40, this has been found to result in an increase in unwanted deposits within the surrounding electrostatic precipitation chamber 60 and so an arrangement is provided which utilises a downcomer 70 which receives the effluent gas treated by the gas scrubber chamber 20 and conveys it from the top of the gas scrubber chamber 20 in the direction C to beneath the sieve floor 50 and the floor of the gas scrubber chamber 20 and into a bottom portion of the electrostatic precipitation chamber 60.

(20) As can be seen, the electrostatic precipitation chamber 60 comprises an annular chamber which surrounds the gas scrubber chamber 20 concentrically. A dividing wall 80 (not shown in FIG. 2) has an inner surface which defines the gas precipitation chamber 20 and an outer surface which defines an inner surface of the electrostatic precipitation chamber 60. An outer wall 90 has an inner surface which defines another surface of the electrostatic precipitation chamber 60.

(21) Positioned between the outer wall 90 and the inner wall 80 is an electrode structure 100 which is retained using an insulator structure 110 which retains the electrode structure 100 using an elongate conductor 170 in a top plate 120 retained and enclosing an upper end of the electrostatic precipitation chamber 60. The electrode structure 100 comprises a generally cylindrical structure having a supporting plate 130 from which a set of elongate electrodes 140 are arranged circumferentially and extend axially along the axial length of the electrostatic precipitation chamber 60.

(22) As can be seen in FIG. 1, the effluent gas from the downcomer 70 enters the lower portion of the electrostatic precipitation chamber 60 and passes upwards in the direction D past the electrode structure 100 and exits through exhaust ports 155 in the direction E as treated gas.

(23) To facilitate the function of the electrostatic precipitation chamber 60, the outer surface of the inner wall 80 is provided with a fluid curtain flowing from the vicinity of the sieve plate 40 downwards towards the floor of the electrostatic precipitation chamber 60. Likewise, the inner surface of the outer wall 90 is provided with a fluid curtain flowing circumferentially from the vicinity of the top plate 120 down towards the floor of the electrostatic precipitation chamber 60.

(24) Sieve Plate

(25) FIG. 4 shows the arrangement of the sieve plate 40 in more detail. As can be seen, the fluid (typically water) is fed through a lower surface of the sieve plate via fluid feeder conduits 75 positioned around the downer 70 which convey the fluid to the sieve plate 40. The sieve plate 40 forms a header tank 41 that maintains a head of fluid, which flows out through an arrangement of holes 45 into the scrubbing chamber 20.

(26) Inner Weir W.sub.I

(27) The fluid retained by the sieve plate 40 also provides the fluid curtain or inner weir W.sub.I which flows down the surface of the inner wall 80. Fluid flows into the gallery 47 through a small gap, exits the lower surface of the gallery 47 and flows down the outer surface of the inner wall 80, as shown in FIG. 5.

(28) Outer Weir W.sub.0

(29) FIG. 6 illustrates the arrangement of the structure providing the outer weir W.sub.0 in more detail. Coupled with the top plate 120 is a plurality of weir sections 125 arranged to form a ring retained by the top plate 120. Each ring section comprises a number of inlets 123 which receive a coupling 129 which provide a fluid. Fluidly coupled with each inlet 123 via a conduit 121 is an outlet 127 which is arranged to eject fluid tangentially from the weir section 125 to form the outer weir W.sub.0 which flows down the inner surface of the outer wall 90.

(30) Electrode Structure Attachment

(31) FIG. 7 shows the electrode structure attachment arrangement in more detail. As can be seen, the electrode structure 100 is retained by a conductor 170 retained by a housing 160 extending from an upper surface of the top plate 120.

(32) An insulator 110 is provided to insulate the electrode structure 100 from the rest of the apparatus 10. The insulator 110 is typically made of glass and a gas purge is provided in order to reduce the concentration of treated effluent gas in the vicinity of the insulator 110, which helps prevent deposits on the insulator which may otherwise lead to the insulator being compromised. As mentioned above, by providing the downer 70, the treated gas in the vicinity of the insulator 110 will have been fully processed by both the gas scrubber chamber 20 and the electrostatic precipitation chamber 60 and so is less likely to cause such deposits.

(33) Electrode Structure

(34) FIG. 8 shows the arrangement of the electrode structure 100 in more detail. The lower portion of FIG. 8 also shows a schematic representation showing the relationship of the electrode structure 100 in relation to the inner wall 80 and the outer wall 90. As can be seen, a number of concentrically arranged elongate electrodes 140 are provided having spikes 150 which extend radially either towards the inner wall 80 or the outer wall 90. In order to maintain a uniform density of discharge points provided by these electrode spikes 150, the ratio of the number of electrode spikes 150 extending towards the inner wall 80 compared to the number of electrode spikes 150 extending towards the outer wall 90 is proportionate to the ratio of the area of the inner wall 80 compared to the outer wall 90.

(35) Concentric Arrangement

(36) FIG. 9 shows the arrangement of the inner wall 80 and the outer wall 90 in more detail. As can be seen, the inner wall 80 is retained within the outer wall 90.

(37) Gas Inlet and Sump

(38) FIG. 10 shows the arrangement of the gas inlet and the sump in more detail. As can be seen, effluent gas to be treated is received through an inlet 200, flows into a sump structure 210 and is fed through the inlets 30 into the lower portion of the gas scrubber chamber 20. Also within the sump structure 210 is fluid containing contaminants extracted from the effluent gas as it is treated within both the scrubbing chamber 20 and the electrostatic precipitation chamber 60. The fluid from the gas scrubbing chamber 20 flows through the inlets 30 into the sump structure 210, whilst the fluid from the electrostatic precipitation chamber 60 flows through conduits 220 into the sump structure 210.

(39) Sieve Plate Fluid Feed

(40) FIG. 11 illustrates the fluid feed provided to feed the sieve plate 40. An inlet 230 is coupled with a fluid supply and conveys fluid via a conduit 240 to a coupling with the feeder conduit 75 which feeds the sieve plate 40.

(41) Tapered Floor

(42) FIG. 12 shows an alternative embodiment of the outer wall 90 which has a tapered or conical floor section 95 which helps prevent the build-up of any sludge on the floor of the electrostatic precipitation chamber 60.

(43) Accordingly, it can be seen that an arrangement is provided which enables both a gas scrubber chamber 20 and an electrostatic precipitation chamber 60 to be provided to perform series treatment of an effluent gas in a much more compact form than was previously possible due to the concentric arrangement of the two treatment chambers. This enables a smaller apparatus to be provided or enables a higher rate of effluent gas treatment for the same apparatus volume.

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

(45) 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.