A plasma adsorption type exhaust gas treatment device

Abstract

This utility model provides a plasma adsorption type exhaust gas treatment device, which includes a reaction chamber, a multi-stage cooling chamber, and an adsorption chamber. An inlet pipe assembly and a plasma igniter are installed on the upper part of the reaction chamber. One end of the multi-stage cooling chamber is connected to the reaction chamber, and the other end is connected to the adsorption chamber. An exhaust pipe assembly is installed on the upper part of the adsorption chamber. Thus, exhaust gas enters the reaction chamber through the inlet pipe assembly. Under the action of the plasma igniter, harmful substances in the exhaust gas decompose due to high temperature. The gas then enters the multi-stage cooling chamber for cooling, and the cooled exhaust gas enters the adsorption chamber to remove fluorides. The exhaust gas treatment device of this application has a simple treatment process, does not require the use of large amounts of water, and the water does not contain harmful substances, eliminating the need for treatment of the wastewater after washing.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing equipment technology, and in particular to a plasma adsorption type exhaust gas treatment device. Background Technology

[0002] In recent years, silicon carbide (SiC) technology has been widely used in power semiconductor devices due to its excellent physical properties and has become increasingly mature. The SiC process often uses fluorine-containing gases, such as silicon tetrafluoride and hydrogen fluoride, as etchants or reaction media, thus generating a large amount of fluorine-containing exhaust gas.

[0003] In existing technologies, water-washing exhaust gas treatment equipment is a common method for treating semiconductor process exhaust gases. Based on the principle of water washing, it uses a spray tower or scrubber to contact the exhaust gas with water, utilizing the solubility of water to remove acidic gases. However, in the treatment of silicon carbide process exhaust gases, the fluorides produced have extremely low water solubility, making them ineffective in dissolving in water. Therefore, water-washing equipment cannot effectively remove harmful substances from silicon carbide process exhaust gases. Furthermore, existing water-washing equipment requires large amounts of water, resulting in significant water resource consumption and a substantial increase in production costs. The wastewater after washing is enriched with high concentrations of harmful substances, requiring additional treatment, which is complex and costly. Utility Model Content

[0004] To solve the above-mentioned technical problems, this application provides a plasma adsorption type exhaust gas treatment device, including a reaction chamber, a multi-stage cooling chamber and an adsorption chamber; The upper part of the reaction chamber is equipped with an air inlet pipe assembly and a plasma igniter. One end of the multi-stage cooling chamber is connected to the reaction chamber, and the other end is connected to the adsorption chamber; An exhaust pipe assembly is provided on the upper part of the adsorption chamber.

[0005] In some embodiments of this application, the multi-stage cooling chamber includes a first-stage cooling chamber, a second-stage cooling chamber, and a third-stage cooling chamber; the first-stage cooling chamber is disposed below the reaction chamber; the second-stage cooling chamber is disposed below the first-stage cooling chamber; and the third-stage cooling chamber is disposed above the second-stage cooling chamber and communicates with the second-stage cooling chamber.

[0006] In some embodiments of this application, the first-stage cooling cavity includes a first-stage cooling cavity body and a cooling plate; the cooling plate is disposed in the first-stage cooling cavity body and is sealed to the first-stage cooling cavity body.

[0007] In some embodiments of this application, a plurality of flow channels are formed on the cooling plate; the plurality of flow channels are respectively connected to the reaction chamber and the second-stage cooling chamber.

[0008] In some embodiments of this application, the flow channel is a spiral flow channel, a straight cylindrical flow channel, or an S-shaped flow channel.

[0009] In some embodiments of this application, the first-stage cooling chamber is provided with an inlet and an outlet; cooling water enters the first-stage cooling chamber from the inlet and is discharged from the outlet.

[0010] In some embodiments of this application, the reaction chamber includes a reaction chamber body and a flow guiding chamber disposed inside the reaction chamber body; the flow guiding chamber has a flow guiding channel whose diameter gradually decreases from top to bottom.

[0011] In some embodiments of this application, the second-stage cooling cavity includes a second-stage cooling cavity body, a condensation assembly, and a first diversion assembly; the condensation assembly is disposed within the second-stage cooling cavity body; the first diversion assembly is detachably disposed on the second-stage cooling cavity body and extends into the second-stage cooling cavity body, thereby forming a multi-stage reversing diversion channel within the second-stage cooling cavity body.

[0012] In some embodiments of this application, the third-stage cooling cavity includes a third-stage cooling cavity body, a condensation assembly, a first flow-diverting assembly, and a second flow-diverting assembly; the condensation assembly is disposed within the third-stage cooling cavity body; the first flow-diverting assembly is detachably disposed on the third-stage cooling cavity body and extends into the third-stage cooling cavity; the second flow-diverting assembly is disposed within the third-stage cooling cavity, and the second flow-diverting assembly vertically divides the third-stage cooling cavity into two cavities; the first flow-diverting assembly and the second flow-diverting assembly together form a multi-stage reversing flow-diverting channel within the third-stage cooling cavity.

[0013] In some embodiments of this application, the cross-sectional shape of the second-stage cooling chamber, the third-stage cooling chamber, and the adsorption chamber is rectangular.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: The plasma adsorption type exhaust gas treatment device of this application includes a reaction chamber, a multi-stage cooling chamber, and an adsorption chamber; an air inlet pipe assembly and a plasma igniter are provided on the upper part of the reaction chamber; one end of the multi-stage cooling chamber is connected to the reaction chamber, and the other end is connected to the adsorption chamber; an exhaust pipe assembly is provided on the upper part of the adsorption chamber; thus, the exhaust gas enters the reaction chamber through the air inlet pipe assembly, and under the action of the plasma igniter, the harmful substances in the exhaust gas decompose due to high temperature, and then enter the multi-stage cooling chamber for cooling. The cooled exhaust gas enters the adsorption chamber to remove fluorides from the exhaust gas; the exhaust gas treatment device of this application has a simple treatment process, does not require the use of a large amount of water, and the water does not contain harmful substances, and there is no need to treat the wastewater after washing.

[0015] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit this document. Attached Figure Description

[0016] The accompanying drawings, which form part of this document, are used to provide a further understanding of the document. The illustrative embodiments and descriptions herein are used to explain the document and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of a plasma adsorption type exhaust gas treatment device (hidden housing) provided in an exemplary embodiment of this application; Figure 2 This is a front view of a plasma adsorption type exhaust gas treatment device (hidden housing) provided in an exemplary embodiment of this application; Figure 3 is a cross-sectional view at point AA in Figure 2; Figure 4 is a cross-sectional view at point BB in Figure 2; Figure 5 This is a top view of a plasma adsorption type exhaust gas treatment device (hidden housing) provided in an exemplary embodiment of this application; Figure 6 yes Figure 5 Sectional view at CC; Figure 7 This is a schematic diagram of the structure of a plasma adsorption type exhaust gas treatment device provided in an exemplary embodiment of this application; Figure 8 This is a schematic diagram of the structure of the first-stage cooling chamber provided in an exemplary embodiment of this application; Figure 9 This is a cross-sectional view of the first-stage cooling chamber provided in an exemplary embodiment of this application.

[0017] In the picture: 10. Intake pipe assembly; 20. Reaction chamber; 30. Multi-stage cooling chamber; 40. Adsorption chamber; 50. Exhaust pipe assembly; 201. Reaction chamber; 202. Flow guide chamber; 203. Air inlet chamber; 301. First-stage cooling chamber; 3011. First-stage cooling chamber; 3012. Cooling plate; 3013. Flow channel; 3014. Water inlet; 3015. Water outlet; 302. Second-stage cooling chamber; 3021. Second-stage cooling chamber; 3022. Condensation assembly; 3023. First flow divider assembly; 3023A. Side plate; 3023B. Horizontal plate; 3023C. Handle; 303. Third-stage cooling chamber; 3031. Third-stage cooling chamber; 3032. Second flow divider assembly. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0019] In recent years, silicon carbide (SiC) technology has been widely used in power semiconductor devices due to its excellent physical properties and has become increasingly mature. The SiC process often uses fluorine-containing gases, such as silicon tetrafluoride and hydrogen fluoride, as etchants or reaction media, thus generating a large amount of fluorine-containing exhaust gas.

[0020] In existing technologies, water-washing exhaust gas treatment equipment is a common method for treating semiconductor process exhaust gases. Based on the principle of water absorption, it uses a spray tower or scrubber to contact the exhaust gas with water, utilizing the solubility of water to remove acidic gases. However, in the treatment of silicon carbide process exhaust gases, the fluorides produced have extremely low water solubility, making them ineffective in dissolving in water. Therefore, water-washing equipment cannot effectively remove harmful substances from silicon carbide process exhaust gases. Furthermore, existing water-washing equipment requires large amounts of water, resulting in significant water resource consumption and a substantial increase in production costs. The wastewater after washing is enriched with high concentrations of harmful substances, requiring additional treatment, which is complex and costly.

[0021] Based on this, an exemplary embodiment of this application provides a plasma adsorption type exhaust gas treatment device, which includes a reaction chamber, a multi-stage cooling chamber, and an adsorption chamber; an air inlet pipe assembly and a plasma igniter are provided on the upper part of the reaction chamber; one end of the multi-stage cooling chamber is connected to the reaction chamber, and the other end is connected to the adsorption chamber; an exhaust pipe assembly is provided on the upper part of the adsorption chamber; thus, the exhaust gas enters the reaction chamber through the air inlet pipe assembly, and under the action of the plasma igniter, the harmful substances in the exhaust gas decompose due to high temperature, and then enter the multi-stage cooling chamber for cooling. The cooled exhaust gas enters the adsorption chamber to remove harmful substances such as fluorides from the exhaust gas; the exhaust gas treatment device of this application has a simple treatment process, does not require the use of a large amount of water, and the water does not contain harmful substances, so there is no need to treat the wastewater after washing.

[0022] Example 1: An exemplary embodiment of this application provides a plasma adsorption type exhaust gas treatment device, such as... Figure 1 and 2As shown, the exhaust gas treatment equipment includes a reaction chamber 20, a multi-stage cooling chamber 30, and an adsorption chamber 40. An inlet pipe assembly 10 and a plasma igniter are installed at the upper part of the reaction chamber 20. One end of the multi-stage cooling chamber 30 is connected to the reaction chamber 20, and the other end is connected to the adsorption chamber 40. An exhaust pipe assembly 50 is installed at the upper part of the adsorption chamber 40. Exhaust gas enters the reaction chamber 20 through the inlet pipe assembly 10. Under the action of the plasma igniter, harmful substances in the exhaust gas decompose due to high temperature. The gas then enters the multi-stage cooling chamber 30 for cooling. The cooled exhaust gas enters the adsorption chamber 40 to remove harmful substances such as fluorides. The exhaust gas treatment equipment of this application has a simple treatment process, does not require the use of large amounts of water, and the water does not contain harmful substances, eliminating the need for treatment of the wastewater after washing.

[0023] like Figure 3 As shown, the reaction chamber 20 includes a reaction chamber body 201 and a flow guide chamber 202 disposed inside the reaction chamber body 201. An air intake chamber 203 is also disposed above the flow guide chamber 202, and an air inlet is provided on the outer peripheral surface of the air intake chamber 203, through which air can be introduced into the air intake chamber 203. The air intake chamber 203 includes a bottom wall and a top wall, which are spaced apart to form a downwardly inclined air intake channel, allowing air to converge towards the center and ensuring complete combustion of the exhaust gas. Preferably, the flow guide chamber 202 has a flow guide channel with a diameter that gradually decreases from top to bottom, which can accelerate the flow of exhaust gas and facilitate its entry into the multi-stage cooling chamber 30.

[0024] Preferably, in order to reduce the temperature of the reaction chamber 201, an inlet 3014 and an outlet 3015 can be provided on the reaction chamber 201. By introducing cooling water between the reaction chamber 201 and the guide chamber 202, the temperature of the outer wall of the reaction chamber 201 can be reduced, thus preventing the outer wall temperature of the reaction chamber 201 from being too high and causing injury to the operator.

[0025] The multi-stage cooling chamber 30 includes a first-stage cooling chamber 301, a second-stage cooling chamber 302, and a third-stage cooling chamber 303. The first-stage cooling chamber 301 is located below the reaction chamber 20; the second-stage cooling chamber 302 is located below the first-stage cooling chamber 301; and the third-stage cooling chamber 303 is located above and communicates with the second-stage cooling chamber 302. Exhaust gas sequentially enters the first-stage cooling chamber 301, the second-stage cooling chamber 302, and the third-stage cooling chamber 303 from the reaction chamber 20, then returns to the second-stage cooling chamber 302, and finally enters the adsorption chamber 40. Figure 3 and 8As shown, the first-stage cooling chamber 301 includes a first-stage cooling chamber body 3011 and a cooling plate 3012; the cooling plate 3012 is disposed within the first-stage cooling chamber body 3011 and is sealed to the first-stage cooling chamber body 3011. Multiple flow channels 3013 are formed on the cooling plate 3012; the multiple flow channels 3013 respectively connect to the reaction chamber 20 and the second-stage cooling chamber 302. For example, to facilitate processing, the flow channels 3013 can be cylindrical flow channels, with multiple flow channels 3013 arranged at equal intervals, their tops connecting to the reaction chamber 20 and their bottoms connecting to the second-stage cooling chamber 302. The first-stage cooling chamber 3011 is equipped with an inlet 3014 and an outlet 3015. Cooling water enters the first-stage cooling chamber 3011 through the inlet 3014 and exits through the outlet 3015. Thus, the space between the first-stage cooling chamber 3011 and the cooling plate 3012 is filled with cooling water. The continuous flow of cooling water reduces the temperature of the cooling plate 3012, thereby reducing the temperature of the gas in the flow channel 3013, achieving the purpose of cooling the exhaust gas after combustion. Simultaneously, the cooled water can be recycled after cooling treatment.

[0026] The second-stage cooling chamber 302 includes a second-stage cooling chamber body 3021, a condensation assembly 3022, and a first diversion assembly 3023; the condensation assembly 3022 is disposed within the second-stage cooling chamber body 3021. Preferably, multiple sets of condensation assemblies 3022 are disposed within the second-stage cooling chamber body 3021, with each set of condensation assemblies 3022 arranged at intervals and parallel to each other. The first diversion assembly 3023 is detachably disposed on the second-stage cooling chamber body 3021 and extends into the second-stage cooling chamber 302, thereby forming a multi-stage reversing diversion channel within the second-stage cooling chamber body 3021. Exemplarily, the first diversion assembly 3023 includes a side plate 3023A, a horizontal plate 3023B, and a handle 3023C; multiple horizontal plates 3023B are spaced apart on the side plate 3023A, and the handle 3023C is disposed on the side of the side plate 3023A away from the horizontal plates 3023B. The second-stage cooling chamber 3021 is provided with a through hole that matches the shape of the side plate 3023A. The side plate 3023A covers and seals the through hole. A guide rail is provided on the inner wall of the second-stage cooling chamber 3021. The horizontal plate 3023B is locked on the guide rail. The first diversion assembly 3023 can be separated from the second-stage cooling chamber 3021 by pulling the handle 3023C, which makes it convenient to clean the impurities accumulated on the horizontal plate 3023B and inside the second cooling chamber.

[0027] like Figure 5 and 6As shown, the second-stage cooling chamber 3021, without the first diversion assembly 3023, has two layers on both sides, forming a space for cooling water circulation. An inlet 3014 is located at the upper part of the outer chamber, and an outlet 3015 is located at the lower part to facilitate cooling water circulation. The condenser assembly 3022 includes condenser tubes and fins fitted onto the condenser tubes. Multiple condenser assemblies 3022 are available. Figure 4 The circular holes in the second-stage cooling chamber 302 and the third-stage cooling chamber 303 shown in the figure are mounting holes for the condenser assembly 3022. For simplicity, only one set of condenser assemblies 3022 is shown in the figure. The two ends of the condenser assembly 3022 are mounted on the inner cavity, and cooling water can enter the condenser tubes, thereby reducing the temperature of the exhaust gas.

[0028] The second-stage cooling chamber 3021 is also equipped with a baffle, which divides the interior of the second-stage cooling chamber 3021 into a first chamber that communicates with the first-stage cooling chamber 3011, a second chamber that communicates with the third-stage cooling chamber 3031, and a third chamber. The first chamber and the second chamber are interconnected at the bottom, so that the exhaust gas enters the first chamber from the first-stage cooling chamber 3011, then enters the second chamber, then enters the third-stage cooling chamber 3031, then enters the third chamber from the third-stage cooling chamber 3031, and finally enters the adsorption chamber 40 and is discharged through the exhaust pipe assembly 50.

[0029] like Figure 4 As shown, the third-stage cooling chamber 303 includes a third-stage cooling chamber body 3031, a condenser assembly 3022, a first flow divider assembly 3023, and a second flow divider assembly 3032; the condenser assembly 3022 is disposed within the third-stage cooling chamber body 3031. The side of the third-stage cooling chamber body 3031 without the first flow divider assembly 3023 is a double-layered chamber, with a space between the two layers for cooling water circulation. An inlet 3014 is provided at the upper part of the outer layer, and an outlet 3015 is provided at the lower part to facilitate cooling water circulation. There are multiple sets of condenser assemblies 3022, with both ends of the condenser assembly 3022 mounted on the inner layer, allowing cooling water to enter the condenser tubes, thereby enabling the condenser assembly 3022 to reduce the temperature of the exhaust gas.

[0030] The first diversion assembly 3023 is detachably mounted on the third-stage cooling chamber 3031 and extends into the third-stage cooling chamber 303. The second diversion assembly 3032 is disposed within the third-stage cooling chamber 303. Exemplarily, the second diversion assembly 3032 includes a first partition arranged vertically and a second partition arranged horizontally. Multiple second partitions are spaced apart on both sides of the first partition. The lower and side parts of the first partition are sealed to the inner wall of the third cooling chamber, and the upper part is spaced apart from the top of the third cooling chamber. The second partitions are spaced apart from the side plate 3023A of the first diversion assembly 3023 in the horizontal direction and from the horizontal plate 3023B of the first diversion assembly 3023 in the vertical direction. Thus, the second diversion assembly 3032 divides the third-stage cooling chamber 303 into two chambers in the vertical direction, forming two gas flow paths inside the third-stage cooling chamber 303. That is, the exhaust gas enters one side of the third-stage cooling chamber 303 from the second-stage cooling chamber 302, flows upward in the vertical direction, then enters the other side of the third-stage cooling chamber 303, then enters the second-stage cooling chamber 302, and finally enters the adsorption chamber 40. In this application, the first diversion component 3023 and the second diversion component 3032 together form a multi-stage reversing diversion channel in the third-stage cooling chamber 3031, which can increase the flow path of the exhaust gas, prolong the exhaust gas cooling time, and reduce the temperature of the exhaust gas.

[0031] Preferably, the cross-sectional shape of the second-stage cooling chamber 302, the third-stage cooling chamber 303, and the adsorption chamber 40 are all rectangular. Thus, with the same floor area, the second-stage cooling chamber 302, the third-stage cooling chamber 303, and the adsorption chamber 40 with circular cross-sections have larger internal spaces, which can improve the processing capacity of the equipment.

[0032] In one exemplary embodiment, there may be two adsorption chambers 40. Both adsorption chambers 40 are connected to the second-stage cooling chamber 302 via valves and pipes. One adsorption chamber 40 is a backup adsorption chamber, and the other is the main adsorption chamber. When cleaning the main adsorption chamber, the backup adsorption chamber can be used without shutting down the equipment. The exhaust pipe assembly 50 is connected to the third-stage cooling chamber 303 via valves and pipes. In special circumstances, this valve can be opened, allowing exhaust gas to enter the exhaust pipe assembly 50 through the valve. Figure 7 As shown, the device also includes a housing, which includes an openable door for easy cleaning of the multi-stage cooling chamber 30 and the adsorption chamber 40.

[0033] Example 2: Based on the above embodiment 1, the main difference between this embodiment and embodiment 1 is that, in this embodiment, as... Figure 9As shown, the cooling plate 3012 has multiple spiral or S-shaped flow channels, or multiple spiral and straight flow channels. The spiral or S-shaped flow channels can increase the gas flow path, and the outer periphery of the flow channel 3013 is filled with cooling liquid. Therefore, the spiral or S-shaped flow channels can further reduce the temperature of the exhaust gas and improve the cooling effect.

[0034] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0035] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0036] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations fall within the scope of the claims of this application and their equivalents, the intent of this application also includes these modifications and variations.

Claims

1. A plasma adsorption type exhaust gas treatment device, characterized in that, It includes a reaction chamber, a multi-stage cooling chamber, and an adsorption chamber; The upper part of the reaction chamber is equipped with an air inlet pipe assembly and a plasma igniter. One end of the multi-stage cooling chamber is connected to the reaction chamber, and the other end is connected to the adsorption chamber; An exhaust pipe assembly is provided at the upper part of the adsorption chamber; The multi-stage cooling chamber includes a first-stage cooling chamber, a second-stage cooling chamber, and a third-stage cooling chamber; the first-stage cooling chamber is located below the reaction chamber; the second-stage cooling chamber is located below the first-stage cooling chamber; and the third-stage cooling chamber is located above the second-stage cooling chamber and communicates with the second-stage cooling chamber. The first-stage cooling chamber includes a first-stage cooling chamber body and a cooling plate; the cooling plate is disposed in the first-stage cooling chamber body and is sealed to the first-stage cooling chamber body. The cooling plate has multiple flow channels; the multiple flow channels are respectively connected to the reaction chamber and the second-stage cooling chamber; the first-stage cooling chamber is provided with a water inlet and a water outlet; cooling water enters the first-stage cooling chamber from the water inlet and is discharged from the water outlet.

2. The plasma adsorption type exhaust processing apparatus according to claim 1, wherein The flow channel is a spiral flow channel, a straight cylindrical flow channel, or an S-shaped flow channel.

3. The plasma adsorption type exhaust processing apparatus according to claim 1, wherein The reaction chamber includes a reaction chamber body and a flow guiding chamber disposed inside the reaction chamber body; the flow guiding chamber has a flow guiding channel whose diameter gradually decreases from top to bottom.

4. The plasma adsorption type exhaust processing apparatus according to claim 1, wherein The second-stage cooling chamber includes a second-stage cooling chamber body, a condensation assembly, and a first flow-diverting assembly; the condensation assembly is disposed within the second-stage cooling chamber body; the first flow-diverting assembly is detachably disposed on the second-stage cooling chamber body and extends into the second-stage cooling chamber body, thereby forming a multi-stage reversing flow-diverting channel within the second-stage cooling chamber body.

5. The plasma adsorption type exhaust processing apparatus according to claim 1, wherein The third-stage cooling chamber includes a third-stage cooling chamber body, a condensation assembly, a first flow-diverting assembly, and a second flow-diverting assembly; the condensation assembly is disposed within the third-stage cooling chamber body; the first flow-diverting assembly is detachably disposed on the third-stage cooling chamber body and extends into the third-stage cooling chamber; the second flow-diverting assembly is disposed within the third-stage cooling chamber, and the second flow-diverting assembly vertically divides the third-stage cooling chamber into two chambers; the first flow-diverting assembly and the second flow-diverting assembly together form a multi-stage reversing flow-diverting channel within the third-stage cooling chamber body.

6. The plasma adsorber exhaust treatment device of claim 1, wherein, The cross-sectional shape of the second-stage cooling chamber, the third-stage cooling chamber, and the adsorption chamber are all rectangular.

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