Apparatus for processing waste gas containing perfluorinated compound

Abstract

This apparatus for processing waste gas containing a perfluorinated compound comprises: a gas chamber having an air supply and exhaust port through which waste gas is supplied or exhausted; a first grid provided in the air supply and exhaust port; a first heat storage unit accommodated in the gas chamber; a catalyst provided on an upper side of the first heat storage unit; a connection unit provided on a lower side of the air supply and exhaust port; a second grid provided on the connection unit; an air supply and exhaust control unit connected to the air supply and exhaust port through the connection unit to supply or exhaust waste gas; a second heat storage unit provided on an upper portion of the second grid; a burner installed outside the gas chamber and heating flowing waste gas in the gas chamber; and an air blowing unit installed outside the gas chamber separately from the burner, having a pipe communicating with the burner to supply air to be combusted to the burner, and configured to control a flow rate of air in accordance with a change in internal pressure of the gas chamber.

Description

Waste gas treatment device containing perfluorinated compounds

[0001] The following description relates to a waste gas treatment device containing perfluorinated compounds.

[0002] Perfluorinated compounds (PFCs) are compounds composed of strongly bonded carbon and fluorine, forming a stable chemical structure. They are heat-resistant and readily permeable to water and oil. However, due to their stable chemical structure, PFCs are difficult to decompose, allowing them to travel through air and water over long periods of time, polluting the environment. In particular, PFCs have a global warming potential thousands to tens of thousands of times greater than carbon dioxide, making them a major contributor to global warming. Furthermore, PFCs are suspected of causing toxicity to the brain, nerves, and liver when accumulated in the human body, and of causing hormonal disruption.

[0003] These perfluorinated compounds are primarily generated during semiconductor manufacturing processes. They are used as cleaning agents, etchants, solvents, and reactant materials for etching, deposition, and chamber cleaning in the semiconductor preprocessing process. Consequently, perfluorinated compounds are included in the exhaust gases emitted during the process, rapidly dispersing into the atmosphere.

[0004] To prevent this, processes are incorporating systems that decompose perfluorinated compounds using methods such as direct combustion, plasma, recovery, and catalysis. However, the significant treatment costs impose a significant financial burden on companies. Among these, catalytic methods are relatively inexpensive and offer high perfluorinated compound decomposition efficiency, leading to their widespread use. However, catalytic methods still present a significant financial burden due to the obvious limitations of catalyst durability.

[0005] Furthermore, conventional processes utilize burners to create temperature conditions for catalytic reactions, but the air flow rate of the blower supplying combustion air to the burner is asymmetrical. This occurs both when the burner is connected to a single blower and when each blower is integrated into the burner. For example, when a single blower is used, the shape and structure of the duct connecting the blower and the burner are complex, resulting in flow rate variations in specific areas within the duct. Furthermore, when the blower and burner are integrated, even if the shape and structure of the duct are simple, the blower fan cannot supply a uniform flow rate across the entire surface, making it impossible to eliminate the air flow rate asymmetry. This means that the flame formed by the burner is not uniform, preventing it from evenly heating the flowing gas within the gas chamber. Consequently, areas that do not meet the temperature conditions for catalytic reactions are formed, potentially leading to the discharge of waste gas that has not been fully catalytically reacted.

[0006] Therefore, it is necessary to develop a technology that can improve the decomposition efficiency or durability of the catalyst and a technology that can form a flame of a certain shape by eliminating the asymmetry of the combustion air supplied to the burner, thereby evenly heating the flowing waste gas while reducing the cost of waste gas treatment.

[0007] The background technology described above is something that the inventor possessed or acquired in the process of deriving the disclosure of the present application, and cannot necessarily be said to be a publicly known technology disclosed to the general public prior to the present application.

[0008]

[0009] The purpose of the embodiment is to provide a waste gas treatment device containing a perfluorinated compound capable of forming a flame of a certain shape by improving the decomposition efficiency or durability of the catalyst and eliminating the asymmetry of combustion air supplied to the burner.

[0010] The problems to be solved in the embodiments are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] A waste gas treatment device containing a perfluorinated compound includes a gas chamber having a supply and exhaust port through which waste gas is supplied or exhausted, a first grid provided in the supply and exhaust port, a first accumulator accommodated in the gas chamber, a catalyst provided on an upper side of the first accumulator, a connection part provided on a lower side of the supply and exhaust port, a second grid provided in the connection part, a supply and exhaust control part connected to the supply and exhaust port through the connection part to supply or exhaust waste gas, a second accumulator provided on an upper side of the second grid, a burner installed outside the gas chamber and heating flowing waste gas in the gas chamber, and a blower installed separately from the burner outside the gas chamber and having a pipe communicating with the burner to supply air for combustion to the burner and control the flow rate of combustion air according to a change in the internal pressure of the gas chamber.

[0012] In one embodiment, the catalyst may be composed of a plurality of catalysts, each of which may be stacked and laminated.

[0013] In one embodiment, the plurality of catalysts may be stacked such that one of the plurality of catalysts gradually fills a portion of another one of the plurality of catalysts adjacent to the bottom.

[0014] According to one embodiment, the gas chamber is divided into a plurality of spaces by a plurality of partitions, and each of the plurality of spaces may have the supply and exhaust ports formed therein, and the first accumulator and the catalyst may be provided.

[0015] According to one embodiment, the plurality of partitions may be formed at a height spaced apart from the upper portion of the gas chamber by a predetermined distance.

[0016] According to one embodiment, the inner and outer walls of the gas chamber, the first grid, the connecting portion, the second grid, and the supply and exhaust control portion may be made of an alloy steel containing Ni, Cr, and Fe, or an alloy steel containing Ni, Cr, Mo, and Fe.

[0017] According to one embodiment, the inner walls of the first grid, the connecting portion, the second grid, and the supply and exhaust control portion may be provided with a coating layer having heat resistance or chemical resistance.

[0018] According to one embodiment, the coating layer may be formed of a composite resin including PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy), FEP (fluorinated ethylene propylene copolymer), or ETFE (ethylene tetrafluoroethylene).

[0019] According to one embodiment, the supply and exhaust control unit may include a plurality of connecting lines each connected to the supply and exhaust ports and having a pipe shape, a plurality of supply lines connected to one side of the plurality of connecting lines and having a pipe shape, an exhaust line connected to the other side of the plurality of connecting lines and having a pipe shape, and a plurality of damper units provided between the connecting lines and the supply lines and between the connecting lines and the exhaust lines to control opening and closing.

[0020] According to one embodiment, the exhaust control unit may include a control unit that controls the damper unit according to a preset cycle.

[0021] According to one embodiment, the connecting portion may be formed in a hopper shape facing the gas chamber.

[0022] According to embodiments, the waste gas treatment device can efficiently treat waste gas through the honeycomb structure of the catalyst, and the blower installed separately from the burner controls the flow rate of combustion air according to changes in the internal pressure of the gas chamber, thereby maintaining the combustion conditions input by the operator constant, and can prevent misfire when the internal pressure in the gas chamber changes significantly.

[0023] The effects of the waste gas treatment device according to the embodiment are not limited to those mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below.

[0024] Figure 1 is a perspective view of a waste gas treatment device according to one embodiment.

[0025] Figure 2 is a cross-sectional view of a waste gas treatment device according to one embodiment.

[0026] Figure 3 is a perspective view of a catalyst according to one embodiment.

[0027] Figure 4 is a perspective view of a catalyst according to another embodiment.

[0028] Fig. 5 is a cross-sectional view of a blower according to one embodiment.

[0029] Fig. 6 is a cross-sectional view showing the structure of a gas chamber and an exhaust control unit according to one embodiment.

[0030] Fig. 7 is a plan view of a supply and exhaust control unit according to one embodiment.

[0031] FIG. 8 is a perspective view of a waste gas treatment device with the gas chamber removed according to one embodiment.

[0032] Figure 9 is a perspective view of a connecting line, an air supply line, and an exhaust line according to one embodiment.

[0033] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, the embodiments may be modified in various ways, and the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, or alternatives to the embodiments are included within the scope of the patent application.

[0034] The terms used in the examples are for illustrative purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood to not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments pertain. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0036]

[0037] In addition, when describing with reference to the attached drawings, identical components will be assigned the same reference numerals regardless of the drawing numbers, and redundant descriptions thereof will be omitted. When describing embodiments, if a detailed description of a related known technology is judged to unnecessarily obscure the gist of the embodiment, the detailed description will be omitted.

[0038] Additionally, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of the embodiments. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms. When a component is described as being "connected," "coupled," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but another component may also be "connected," "coupled," or "connected" between each component.

[0039] Components included in one embodiment and components with common functions will be described using the same names in other embodiments. Unless otherwise stated, the descriptions given in one embodiment can be applied to other embodiments, and detailed descriptions will be omitted to the extent of overlap.

[0040] Hereinafter, the present embodiment will be described with reference to the drawings. For reference, FIG. 1 is a perspective view of a waste gas treatment device (10) according to one embodiment, FIG. 2 is a cross-sectional view of a waste gas treatment device (10) according to one embodiment, FIG. 3 is a perspective view of a catalyst (130) according to one embodiment, FIG. 4 is a perspective view of a catalyst (130) according to another embodiment, FIG. 5 is a cross-sectional view of a blower (190) according to one embodiment, FIG. 6 is a cross-sectional view showing the structure of a gas chamber (100) and an exhaust control unit (160) according to one embodiment, FIG. 7 is a plan view of a supply and exhaust control unit (160) according to one embodiment, FIG. 8 is a perspective view of a waste gas treatment device (10) with the gas chamber (100) removed according to one embodiment, and FIG. 9 is a perspective view of a connection line (161), an air supply line (162), and an exhaust line (163) according to one embodiment.

[0041] The waste gas treatment device (10) includes a gas chamber (100), a first grid (110), a first heat storage unit (120), a catalyst (130, 130'), a connection unit (140), a second grid (150), an exhaust and supply control unit (160), a second heat storage unit (170), a burner (180), and a blower unit (190).

[0042] The waste gas treatment device (10) is made of an alloy steel containing Ni, Cr, and Fe or an alloy steel containing Ni, Cr, Mo, and Fe, with inner and outer walls of a gas chamber (100), a first grid (110), a connecting portion (140), a second grid (150), and an exhaust / supply control portion (160).

[0043] More specifically, the Ni-Cr-Fe alloy steel may be composed of 73 to 79% Ni, 14 to 16% Cr, and 4 to 11% Fe by weight, along with unavoidable impurities.

[0044] Ni-Cr-Mo-Fe alloy steel may be composed of 60 to 62% Ni, 21 to 22% Cr, 8 to 10% Mo, and 7 to 9% Fe by weight, with unavoidable impurities.

[0045] Alternatively, the Ni-Cr-Mo-Fe alloy steel may be composed of 56 to 58% Ni, 15 to 17% Cr, 15 to 17% Mo, and 5 to 6% Fe by weight with unavoidable impurities.

[0046] Alternatively, the Ni-Cr-Mo-Fe alloy steel may be composed of 58 to 60% Ni, 20 to 21% Cr, 14.0 to 14.5% Mo, and 2.2 to 2.4% Fe by weight, with inevitable impurities.

[0047] In addition, the waste gas treatment device (10) is provided with a heat-resistant or chemical-resistant coating layer on the inner walls of the first grid (110), the connecting portion (140), the second grid (150), and the supply and exhaust control portion (160). At this time, the coating layer is made of a composite resin including PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy), FEP (fluorinated ethylene propylene copolymer), or ETFE (ethylene tetrafluoroethylene).

[0048] The gas chamber (100) is formed with a supply / exhaust port (111) through which waste gas is supplied or exhausted. For example, the gas chamber (100) has an inner circumference formed of a floor, side walls, and a ceiling in the form of walls, thereby sealing the internal space and allowing the gas chamber (100) to be supported at a predetermined height by a support frame (114). In addition, the gas chamber (100) may be provided with a refractory member on the surfaces of the side walls and the ceiling.

[0049] The gas chamber (100) is divided into a plurality of spaces by a plurality of partitions (112), and each of the plurality of compartment spaces (113) is provided with a supply and exhaust port (111) and a first heat storage unit (120) and a catalyst (130). That is, each compartment space (113) is a reduced version of the gas chamber (100), and each has the same shape and structural effect. More specifically, each of the plurality of compartment spaces (113) has a supply and exhaust port (111) formed on its lower surface, thereby enabling the supply and exhaust of waste gas throughout the lower surface of the gas chamber (100). In addition, in each compartment space (113), the catalyst (130) is integrally stacked on the upper portion of the first heat storage unit (120) so as to come into contact with the waste gas that has been processed at high temperatures.

[0050] A plurality of partitions (112) are formed at a height spaced apart from the upper portion of the gas chamber (100) by a predetermined distance. In this configuration, the plurality of partitions (112) divide the interior of the gas chamber (100) into a plurality of spaces, but the upper portion of each compartment space (113) is open, so that waste gas can flow between each compartment space (113).

[0051] The first grid (110) is provided in the supply and exhaust port (111). At this time, the first grid (110) is positioned below the stacking of the catalyst (130) and the first heat storage unit (120), and is formed in the form of a metal grid having a plurality of openings so as to support the catalyst (130) and the first heat storage unit (120) while providing a flow path for the supplied waste gas. In addition, the grid shape of the first grid (110) can form a uniform airflow by dispersing the flowing waste gas, and can also prevent dust from entering the inside of the gas chamber (100) and heat loss from the first heat storage unit (120).

[0052] The first accumulator (120) is accommodated in the gas chamber (100).

[0053] A catalyst (130) is provided on the upper side of the first accumulator (120). The catalyst (130) is manufactured to cause a chemical reaction when in contact with a perfluorinated compound, and can cause a difficult-to-decompose perfluorinated compound to be decomposed at a temperature of 800°C or lower through a chemical reaction.

[0054] In addition, the catalyst (130) is formed in a plurality of pieces, and each piece is stacked to form a layer. For example, the plurality of catalysts (130) may be formed in a structure in which one or two or more shapes are combined among a hexagonal or square type honeycomb shape, a bead shape, and a pellet shape. In this embodiment, a honeycomb structured catalyst (130) is described with reference to FIG. 3 for exemplary explanation, and the remaining bead shapes and pellet shapes are examples of shape variations of the honeycomb structured catalyst (130), so specific diagrams and descriptions are omitted without further limitation. The honeycomb structured catalyst (130) can come into contact with the waste gas that has passed through the first storage unit (120) by corresponding the horizontal plane cross-section and area of ​​the partition space (113) on the upper side of the first storage unit (120). In addition, in the present embodiment, one catalyst (130) means a honeycomb structure in which a plurality of hollow hexagonal columns are combined until they correspond to the horizontal cross-section of the compartment space (113). The catalyst (130) can chemically react by coming into contact with the flowing waste gas after passing through the first accumulator (120). At this time, the hollow catalyst (130) causes the waste gas to pass through the openings and come into contact with the inner surface of the catalyst (130) to chemically react. In addition, since the catalyst (130) is combined in a honeycomb structure, the outer surface forming each opening becomes the inner surface forming the opening in the adjacent opening, thereby minimizing the portion that does not come into contact with the waste gas. Since the entire surface of the catalyst (130) is evenly in contact with the waste gas, the reaction efficiency is higher than that of a conventional granular type catalyst.

[0055] Meanwhile, a plurality of catalysts (130) are stacked while filling a portion of one of a plurality of other catalysts (130) adjacent to the lower side. For example, assuming that a honeycomb-structured catalyst (130) is used among a plurality of catalysts, a second-layer catalyst stacked on the lowest catalyst may be provided so that its bottom covers a portion of the hexagonal or square opening of the lowest catalyst, and the catalysts stacked next may be provided so as to cover the remaining openings of the openings, and this can be repeated. Through this, the plurality of catalysts (130) can secure a flow path for waste gas by blocking only a portion of the openings of adjacent catalysts. In addition, since the plurality of catalysts (130) are repeatedly stacked in the same form, the time for waste gas to reach the uppermost catalyst can be delayed, thereby increasing the chemical reactivity with the waste gas.

[0056] Alternatively, the catalyst (130') may be formed in a granular form with multiple square grooves formed over the entire surface to form a honeycomb ball structure. The honeycomb ball type catalyst (130') may be formed in multiple pieces so as to fill the compartment space (113) in the horizontal cross-section direction. In this configuration, the catalyst (130') allows the waste gas flowing inside the gas chamber (100) to be evenly chemically reacted by being dispersed by the multiple square grooves.

[0057] The connecting part (140) is provided on the lower side of the supply and exhaust port (111), and the connecting part (140) is formed in a hopper shape facing the gas chamber (100).

[0058] The second grid (150) is provided in the connecting portion (140). The second grid (150) has the same material, shape, arrangement, and effect as the first grid (110), so that it can disperse the airflow of waste gas passing through the opening of the connecting portion (140) and prevent dust from entering through the waste gas and heat loss from the first heat storage portion (120).

[0059] The exhaust control unit (160) is connected to the exhaust port (111) through a connection unit (140) to supply or exhaust waste gas, and includes a plurality of connection lines (161), a plurality of supply lines (162), a plurality of exhaust lines (163), a plurality of damper units (164), and a control unit (165).

[0060] More specifically, a plurality of connecting lines (161) have a pipe shape and are respectively connected to the supply and exhaust ports (111). The air supply line (162) has a pipe shape and is connected to one side of the connecting line (161). The exhaust line (163) has a pipe shape and is connected to the other side of the connecting line (161). A plurality of damper parts (164) are respectively provided between the connecting line (161) and the air supply line (162) and between the connecting line (161) and the exhaust line (163) to control opening and closing. The control part (165) controls the damper parts (164) according to a preset cycle. Through this, the air supply and exhaust control part (160) can control the exhaust gas to be individually supplied or exhausted to each compartment space (113). For example, the exhaust control unit (160) can change the state of communication between each pipeline by controlling a plurality of damper units (164) so ​​that the waste gas flows in the direction set by the control unit (165), so that if the waste gas is supplied to one of the plurality of compartment spaces (113), the waste gas is exhausted from the other one, thereby improving the heat recovery rate.

[0061] Additionally, the damper section (164) can be formed in a cylindrical shape, and the linear motion direction can be perpendicular or horizontal to the longitudinal direction of each pipe line.

[0062] In addition, each connecting line (161) is equipped with a collection container (166) at the bottom to accommodate dust discharged from the waste gas. At this time, the collection container (166) is equipped with inspection holes on the inner and outer surfaces, similar to the connecting portion (140), to enable easy internal monitoring.

[0063] The second heat accumulator (170) is provided on the upper part of the second grid (150). At this time, the second heat accumulator (170) is located between the upper part of the second grid (150) and the outer side of the bottom surface of the gas chamber (100), so that it is easy to replace, and since it preheats the waste gas directed toward the inside of the gas chamber (100), heat loss of the first heat accumulator (120) can be minimized.

[0064] That is, the waste gas treatment device (10) has a double grid structure composed of a first grid (110) and a second grid (150) and a double heat storage structure composed of a first heat storage unit (120) and a second heat storage unit (170), thereby having a longer product life than when it is a single structure.

[0065] A burner (180) is installed in a gas chamber (100) and heats the flowing waste gas within the gas chamber (100). For example, the burner (180) may be installed in any one of a plurality of compartment spaces (130) and heat the waste gas flowing through the compartment space (130) while passing through a catalyst (130, 130').

[0066] At this time, the blower (190) is installed separately from the burner (180) outside the gas chamber (100), and is provided with a pipe (not shown) that communicates with the burner (180) to supply air for combustion to the burner (180), and controls the flow rate of combustion air according to changes in the internal pressure of the gas chamber (100).

[0067] In this embodiment, the waste gas treatment device (10) enables efficient waste gas treatment through the honeycomb structure of the catalyst (130), and the blower (190) installed separately from the burner (180) controls the flow rate of combustion air according to the change in the internal pressure of the gas chamber (100), thereby maintaining the combustion conditions input by the operator constant, and can prevent misfire when the internal pressure in the gas chamber (100) changes significantly.

[0068] Although the embodiments described above have been described with limited drawings, those skilled in the art will appreciate that various technical modifications and variations can be applied based on the above. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

[0069] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. A gas chamber in which a supply and exhaust port is formed through which waste gas is supplied or exhausted; A first grid provided in the above exhaust device; A first accumulator accommodated in the above gas chamber; A catalyst provided on the upper side of the first accumulator; A connecting part provided on the lower side of the above exhaust device; A second grid provided in the above connecting portion; A supply and exhaust control unit connected to the supply and exhaust port through the above connection unit to supply or exhaust waste gas; A second heat storage unit provided on the upper part of the second grid; A burner installed outside the gas chamber and heating the flowing waste gas within the gas chamber; and A blower which is installed separately from the burner outside the gas chamber and has a pipe communicating with the burner to supply air for combustion to the burner and controls the flow rate of combustion air according to changes in the internal pressure of the gas chamber; A waste gas treatment device containing perfluorinated compounds.

2. In paragraph 1, A waste gas treatment device containing a perfluorinated compound, wherein the above catalyst is composed of a plurality of catalysts, each of which is stacked and laminated.

3. In paragraph 2, A waste gas treatment device containing a perfluorinated compound in which the plurality of catalysts are stacked while gradually filling a portion of another one of the plurality of catalysts adjacent to the lower side.

4. In paragraph 1, The above gas chamber is divided into multiple spaces by multiple partitions, A waste gas treatment device containing a perfluorinated compound, wherein each of the plurality of spaces has the above-mentioned exhaust port formed therein, and the first accumulator and the catalyst are provided.

5. In paragraph 4, A waste gas treatment device containing a perfluorinated compound, wherein the above plurality of partitions are formed at a height spaced apart from the upper portion of the gas chamber by a predetermined distance.

6. In paragraph 1, A waste gas treatment device containing a perfluorinated compound, wherein the inner and outer walls of the gas chamber, the first grid, the connecting portion, the second grid, and the supply and exhaust control portion are made of alloy steel containing Ni, Cr, and Fe or alloy steel containing Ni, Cr, Mo, and Fe.

7. In paragraph 1, A waste gas treatment device containing a perfluorinated compound, wherein the inner walls of the first grid, the connecting portion, the second grid, and the exhaust control portion are provided with a coating layer having heat resistance or chemical resistance.

8. In paragraph 7, The above coating layer is a waste gas treatment device containing a perfluorinated compound made of a composite resin including PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy), FEP (fluorinated ethylene propylene copolymer) or ETFE (ethylene tetrafluoroethylene).

9. In paragraph 1, The above-mentioned supply and exhaust control unit is a waste gas treatment device including a perfluorinated compound, which includes a plurality of connecting lines each connected to the supply and exhaust ports and having a pipe shape, a plurality of supply lines connected to one side of the plurality of connecting lines and having a pipe shape, an exhaust line connected to the other side of the plurality of connecting lines and having a pipe shape, and a plurality of damper parts provided between the connecting lines and the supply lines and between the connecting lines and the exhaust lines to control opening and closing.

10. In paragraph 9, A waste gas treatment device containing a perfluorinated compound, wherein the above exhaust control unit has a control unit that controls the damper unit according to a preset cycle.

11. In paragraph 1, The above connection part is a waste gas treatment device containing a perfluorinated compound formed in a hopper shape facing the gas chamber.

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