Patent Publication Number: US-2023151782-A1

Title: Canister

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority based on Japanese Patent Application No. 2021-185059 filed to Japanese Patent Office on Nov. 12, 2021, and the content of Japanese Patent Application No. 2021-185059 is incorporated by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to a canister. 
     A canister that prevents release of evaporated fuel to the atmosphere is mounted on a fuel tank of a vehicle. The canister adsorbs evaporative fuel to an adsorbent such as activated carbon, desorbs the fuel from the adsorbent by sucked air, performs purging, and supplies the evaporative fuel to the engine. Japanese Patent Application Laid-Open No. 2021-50656 (hereinafter, Patent Document 1) discloses a canister that accommodates a honeycomb adsorbent. Specifically, in the canister described in Patent Document 1, a round tubular housing accommodates a round columnar honeycomb adsorbent. 
     SUMMARY 
     However, in the canister described in Patent Document 1, when the honeycomb adsorbent is inserted into the housing, there is a possibility that the honeycomb adsorbent comes into contact with an opening end of an opening of the housing and is damaged. 
     One aspect of the present disclosure preferably provides a technique capable of appropriately holding an adsorbent while suppressing breakage of the adsorbent when the adsorbent is inserted into a canister. 
     An aspect of the present disclosure is a canister that adsorbs and desorbs evaporative fuel generated in a fuel tank of a vehicle. The canister includes an adsorbent and a tubular body. The adsorbent is formed into one mass that adsorbs the evaporative fuel. The tubular body has a tubular shape and holds the adsorbent in a state where the adsorbent is inserted therein. A contact surface that is at least a partial area of an inner wall surface of the tubular body in a length direction of a central axis is brought into contact with a side surface of the inserted adsorbent to suppress movement of the adsorbent in a direction orthogonal to the central axis. The tubular body has an inclined surface in which the inner wall surface is inclined in a direction approaching the central axis of the tubular body in at least a partial area of an area from a starting point to the contact surface, the starting point being an opening end of an opening into which the adsorbent can be inserted. 
     According to such a configuration, in the tubular body, the opening end of the opening into which the adsorbent can be inserted is wider than a distal end on an insertion side of the adsorbent. Therefore, when the adsorbent is inserted, the adsorbent can be prevented from coming into contact with the opening end of the opening. Therefore, it is possible to suppress breakage of the adsorbent when the adsorbent is inserted. In addition, since the movement of the adsorbent is suppressed by the contact surface, the canister can appropriately hold the adsorbent. 
     In the canister described above, the inclined surface may be formed in at least a partial area of the contact surface, and form a cross-sectional area in the direction orthogonal to the central axis, the cross-sectional area decreasing from an opening side of the contact surface toward an opposite side of the opening in the length direction of the central axis of the contact surface. According to such a configuration, a portion on the opening side of the contact surface is wider than the distal end on the insertion side of the adsorbent. Therefore, when the adsorbent is inserted, the adsorbent can be prevented from coming into contact with the portion on the opening side of the contact surface. Therefore, it is possible to suppress breakage of the adsorbent when the adsorbent is inserted. 
     In the canister described above, the inclined surface may be formed in at least a partial area between the opening and an end portion on the opening side of the contact surface, and form a cross-sectional area in the direction orthogonal to the central axis, the cross-sectional area decreasing from the opening side toward the end portion on the opening side of the contact surface. According to such a configuration, the opening is wider than the distal end on the insertion side of the adsorbent. Therefore, when the adsorbent is inserted, the adsorbent can be prevented from coming into contact with the opening. Therefore, it is possible to suppress breakage of the adsorbent when the adsorbent is inserted. 
     The canister described above may further include a filter that closes the opening. A welded portion where a wall surface forming the opening and the filter are welded may be provided. According to such a configuration, the movement of the adsorbent in the direction of the filter is suppressed. Therefore, the removal of the adsorbent from the tubular body can be suppressed. 
     The canister described above may further include an outer shell member that houses the tubular body. According to such a configuration, damage to the tubular body can be suppressed by the outer shell member. 
     In the canister described above, the outer shell member may be directly or indirectly brought into contact with the adsorbent to suppress the removal of the adsorbent in the direction opposite to the direction in which the adsorbent is inserted. According to such a configuration, the removal of the adsorbent from the tubular body can be suppressed. 
     In the canister described above, the adsorbent may be an elastically deformable mass of activated carbon. According to such a configuration, it is easy to prevent generation of a gap between the tubular body and the adsorbent. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which: 
         FIG.  1    is a cross-sectional view of a canister according to a first embodiment as viewed from the side. 
         FIG.  2    is a cross-sectional view of a second chamber as viewed from the side and an enlarged view of a cross-sectional view of a second adsorption chamber as viewed from the side. 
         FIG.  3    is a schematic view when an adsorbent is inserted into an inner case. 
         FIG.  4    is a cross-sectional view of the second chamber as viewed from the side and an enlarged view of the cross-sectional view of the second adsorption chamber as viewed from the side in a configuration in which cross-sectional areas in a direction orthogonal to a central axis of an inner case are substantially the same. 
         FIG.  5    is a cross-sectional view of a canister according to a second embodiment as viewed from the side. 
         FIG.  6    is a cross-sectional view of a canister not including an inner case as viewed from the side. 
         FIG.  7    is a cross-sectional view of a canister not including an inner case or a filter as viewed from the side. 
         FIG.  8    is a cross-sectional view of a canister not including a filter as viewed from the side. 
         FIG.  9    is a cross-sectional view of a canister in which an opening of the second adsorption chamber faces the side as viewed from the side. 
         FIG.  10 A  is an enlarged view of a cross-sectional view of a canister according to a modification of the second embodiment as viewed from the side, and is a view of the canister configured such that a portion between an opening into which an adsorbent can be inserted and an end portion on an opening side of a contact surface protrudes toward an internal space of the second chamber. 
         FIG.  10 B  is an enlarged view of a cross-sectional view of a canister according to a modification of the second embodiment as viewed from the side, and is a view of the canister configured such that the portion between the opening into which the adsorbent can be inserted and the end portion on the opening side of the contact surface protrudes toward the outside of the second chamber. 
         FIG.  11 A  is an enlarged view of a cross-sectional view of a canister according to a modification as viewed from the side, and is a view of the canister in which a central axis is inclined with respect to the length direction of the inner case. 
         FIG.  11 B  is an enlarged view of a cross-sectional view of a canister according to a modification as viewed from the side, and is a view of the canister in which an inclined surface is formed in an area shorter than the contact surface in the length direction of the inner case. 
         FIG.  11 C  is an enlarged view of a cross-sectional view of a canister according to a modification as viewed from the side, and is a view of the canister in which an inclined surface is formed in an area longer than the contact surface in the length direction of the inner case. 
         FIG.  11 D  is an enlarged view of a cross-sectional view of a canister according to a modification as viewed from the side, and is a view of the canister in which a partial area is not inclined in a portion between an opening into which an adsorbent is inserted and an end portion on an opening side of a contact surface. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     1. First Embodiment 
     1-1. Configuration 
     A canister  1  illustrated in  FIG.  1    adsorbs and desorbs evaporative fuel generated in a fuel tank (not illustrated) of a vehicle. The canister  1  includes an outer case  2 , an inner case  3 , and an adsorbent  4 . 
     The outer case  2  is a case having an internal space. The outer case  2  is a synthetic resin case. Note that the material of the outer case  2  is not limited thereto. 
     The outer case  2  includes a charge port  21 , a purge port  22 , and an atmosphere port  23 . These ports are arranged on the same side of the case so as to face in the same direction. Hereinafter, the side of the outer case  2  on which the charge port  21 , the purge port  22 , and the atmosphere port  23  are provided will be referred to as a port side. The outer case  2  has an opening  64  on the side opposite to the port side. The opening  64  is closed by a lid member  31 . Hereinafter, the side opposite to the port side (in other words, the side on which the lid member  31  is provided) is referred to as a lid side. 
     The charge port  21  is connected to the fuel tank of the vehicle by piping. The charge port  21  is configured to take evaporative fuel generated in the fuel tank into the canister  1 . 
     The purge port  22  is connected to an intake pipe (not illustrated) of an engine of the vehicle via a purge valve. The purge port  22  is configured to discharge evaporative fuel in the canister  1  from the canister  1  and supply the evaporative fuel to the engine. 
     The atmosphere port  23  is connected to a fuel filler port (not illustrated) of the vehicle via piping and is opened to the atmosphere. The atmosphere port  23  discharges the gas from which the evaporative fuel has been removed into the atmosphere. The atmosphere port  23  takes in external air (i.e., purge air) to desorb (i.e., purge) the evaporative fuel adsorbed by the canister  1 . 
     The internal space of the outer case  2  is partitioned into a first chamber  25  and a second chamber  26  by a partition member  27 . 
     As an example, the first chamber  25  has a substantially rectangular parallelepiped shape or a round columnar shape. The first chamber  25  has an end portion on the port side connected to the charge port  21  and the purge port  22 . A filter  32  is disposed at the end portion on the port side of the first chamber  25 . A filter  33  is disposed at an end portion on the lid side of the first chamber  25 . An adsorbent  40  is disposed between the filter  32  and the filter  33 . The adsorbent  40  is, for example, an aggregate of a plurality of pellets. The pellets are granular activated carbon. The pellets are produced by kneading powdery activated carbon together with a binder and molding the kneaded product into a predetermined shape. In the first chamber  25 , for example, an adsorbent other than pellets such as powdery activated carbon may be disposed. 
     The end portion on the lid side of the first chamber  25  is connected to a communication path  34 . The communication path  34  extends along the lid member  31  and connects the first chamber  25  and the second chamber  26 . A perforated plate  36  having permeability for transmitting fuel vapor and purge air is disposed between the filter  33  on the lid side of the first chamber  25  and the communication path  34 . Coil springs  37  are disposed between the perforated plate  36  and the lid member  31 . The coil springs  37  press the perforated plate  36  toward the port side. Inside the canister  1 , a fluid can travel back and forth between the first chamber  25  and the second chamber  26  via the communication path  34 . 
     The second chamber  26  has an elongated shape extending from the communication path  34  to the atmosphere port  23 . As an example, the second chamber  26  has a substantially rectangular parallelepiped shape or a round columnar shape. The second chamber  26  has an end portion on the port side connected to the atmosphere port  23 . A filter  38  is disposed at an end portion on the lid side of the second chamber  26 . A filter  39  is disposed at an end portion on the port side of the second chamber  26 . The inner case  3  is disposed between the filter  39  and the lid member  31  in the second chamber  26 . A welded portion  76  is formed at an end portion on the port side of the inner case  3 . At the welded portion  76 , the filter  39  is fixed to the end portion on the port side of the inner case  3  by ultrasonic welding, for example. 
     A perforated plate  41  having permeability for transmitting fuel vapor and purge air is disposed between the filter  38  on the lid side of the second chamber  26  and the communication path  34 . Coil springs  42  are disposed between the perforated plate  41  and the lid member  31 . The coil springs  42  press the perforated plate  41  toward the port side. 
     The inner case  3  is housed inside the outer case  2 . The inner case  3  has a tubular shape. More specifically, the inner case  3  has a round tubular shape whose inner diameter is not constant over the entire length direction of a central axis  80 . In the vicinity of an upper end of the inner case  3 , the degree of change in the inner diameter toward the port side is larger than that of most of the other part, and the inner diameter of most of the other part gradually changes toward the lid side. The inner case  3  has a circular cross-sectional shape at any position in the length direction of the central axis  80 . That is, the inner case  3  has a shape of a rotating body centered on the central axis  80 . The inner case  3  is obtained by, for example, molding resin using a mold. The inner case  3  is partitioned by a partition plate  53  into a first adsorption chamber  51  and a second adsorption chamber  52  arranged in a flow direction of the fluid. The partition plate  53  is formed integrally with the inner case  3 . The partition plate  53  has a vent hole. Therefore, inside the inner case  3 , the fluid can travel back and forth between the first adsorption chamber  51  and the second adsorption chamber  52  via the partition plate  53 . A filter  54  is disposed adjacent to the partition plate  53  on a surface of the partition plate  53  on the lid side. An adsorbent  43  is disposed between the filter  38  and the filter  54 , that is, in the first adsorption chamber  51 . Note that the adsorbent  43  may be of the same type as the adsorbent  40 , or may be of a different type. 
     The second adsorption chamber  52  has an inclined surface  93  which is inclined in a direction in which an inner wall surface of the second adsorption chamber  52  approaches the central axis  80  of the inner case  3  from an opening end  96  of an opening  62  described later as a starting point. As a result, the second adsorption chamber  52  is configured to be partially tapered. More specifically, in the second adsorption chamber  52 , the cross-sectional area in a direction orthogonal to the central axis  80  of the inner case  3  decreases within a certain area from an end portion on the port side of the second adsorption chamber  52  toward an end portion on the lid side of both ends of the second adsorption chamber  52 . Here, the central axis  80  is a straight line passing through the center of gravity of a circular cross section in each portion of the inner case  3 . The adsorbent  4  is disposed in the second adsorption chamber  52 . The adsorbent  4  is an elastically deformable mass of activated carbon. As an example, the adsorbent  4  is one block-shaped agglomerate obtained by mixing activated carbon into sponge. The adsorbent  4  is configured to have substantially the same shape as the tapered portion of the second adsorption chamber  52 . More specifically, the adsorbent  4  is formed in a truncated cone shape. The second adsorption chamber  52  holds the adsorbent  4  in a state where the adsorbent  4  is inserted therein. 
     As illustrated in  FIG.  2   , an opening  62  into which the adsorbent  4  can be inserted is formed at the end portion on the port side of the second adsorption chamber  52 . The inner diameter of the opening  62  is larger than the maximum dimension of the outer diameter of the adsorbent  4 . An opening  63  is also formed at the end portion on the lid side of both ends of the second adsorption chamber  52 . The second adsorption chamber  52  has a contact surface  60 . The contact surface  60  is an inner wall surface of the second adsorption chamber  52 , that is, an inner side surface. The contact surface  60  suppresses movement of the adsorbent  4  in the direction orthogonal to the central axis  80  of the inner case  3  by being brought into contact with an outer side surface of the inserted adsorbent  4 . In addition, the outer case  2  is indirectly brought into contact with the adsorbent  4  to suppress removal of the adsorbent  4  in the direction opposite to a direction in which the adsorbent  4  is inserted. In the present embodiment, the contact surface  60  corresponds to an example of an inclined surface. 
     Returning to  FIG.  1   , a buffer space  61  is provided on the lid side of both ends of the second adsorption chamber  52 . The adsorbent  4  and the adsorbent  43  are not disposed in the buffer space  61 . 
     1-2. Method of Assembling Inner Case to Outer Case 
     As illustrated in  FIG.  3   , first, the adsorbent  4  is inserted into the second adsorption chamber  52  of the inner case  3  from the opening  62  on the port side of the inner case  3 . The adsorbent  4  is inserted by being moved in parallel with respect to the state of being held in the second adsorption chamber  52 . 
     Subsequently, the filter  39  is fixed to the end portion on the port side of the inner case  3  by ultrasonic welding. 
     Subsequently, the inner case  3  is inserted into the second chamber  26  of the outer case  2  from the opening  64  on the lid-side of the outer case  2 . The inner case  3  is assembled to the outer case  2  in a state of a cartridge filled with the adsorbent  4 . After the inner case  3  is assembled, the lid member  31  of the outer case  2  is assembled to the outer case  2 . 
     1-3. Effects 
     According to the first embodiment described in detail above, the following effects can be obtained. 
     (1a) In the second adsorption chamber  52 , the cross-sectional area in the direction orthogonal to the central axis  80  of the inner case  3  decreases from the end portion on the port side of the second adsorption chamber  52  toward the end portion on the lid side of both ends of the second adsorption chamber  52 . Here, as illustrated in  FIG.  4   , an inner case  3   a  in which the diameter of an internal space (second adsorption chamber  182 ) does not change at an end on the port side is assumed. When an adsorbent material  74  having the same cross-sectional shape as the internal space is inserted into the inner case  3   a , the adsorbent  74  may hit the opening end  96  of the opening on the port side of the inner case  3   a , be scraped, and be damaged. However, according to a configuration of the first embodiment, the opening end  96  of the opening of the inner case  3   a  into which the adsorbent  4  can be inserted is wider than a distal end on an insertion side of the adsorbent  4 . Therefore, when the adsorbent  4  is inserted, the adsorbent  4  can be prevented from coming into contact with the opening end  96  of the opening. Therefore, it is possible to suppress breakage of the adsorbent  4  when the adsorbent  4  is inserted. 
     In addition, as illustrated in  FIG.  4   , it is assumed that the second adsorption chamber  182  does not include the inclined surface  93  and includes a support portion  75  that supports the adsorbent  74  so as not to fall on the lid side of both ends of the second adsorption chamber  182 . In this case, the flow of evaporative fuel may be deteriorated near the support portion  75 . This is because, when the cross-sectional area of a flow path rapidly changes, a vortex flow is generated at a portion where the cross-sectional area rapidly changes, thereby inhibiting smooth flow. According to the configuration of the first embodiment, however, the evaporative fuel flows more smoothly along the inclined surface  93  as compared with the configuration including the support portion  75 . Accordingly, the flow of evaporative fuel can be improved. 
     (1b) The filter  39  is fixed to the end portion on the port side of the inner case  3  by ultrasonic welding. According to such a configuration, the movement of the adsorbent  4  in the direction of the filter  39  is suppressed. Therefore, the removal of the adsorbent  4  from the inner case  3  can be suppressed. Together with an effect of ( 1   d ) described later, it is possible to further suppress the removal of the adsorbent  4  from the inner case  3 . 
     (1c) In the canister  1 , the inner case  3  is housed inside the outer case  2 . According to such a configuration, damage to the inner case  3  can be suppressed by the outer case  2 . 
     (1d) The outer case  2  is indirectly brought into contact with the adsorbent  4  to suppress the removal of the adsorbent  4  in the direction opposite to a direction in which the adsorbent  4  is inserted. According to such a configuration, the removal of the adsorbent  4  from the inner case  3  can be suppressed. 
     (1e) The adsorbent  4  is an elastically deformable mass of activated carbon. According to such a configuration, the adsorbent  4  can be disposed in the inner case  3  so as not to form a gap. Accordingly, leakage of evaporative fuel from between the inner case  3  and the adsorbent  4  can be suppressed. 
     1-4. Correspondence 
     In the present embodiment, the inner case  3  corresponds to an example of a tubular body, and the outer case  2  corresponds to an example of an outer shell member. 
     2. Second Embodiment 
     A basic configuration of a second embodiment illustrated in  FIG.  5    is similar to that of the first embodiment, and differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and reference is made to the preceding description. 
     In the first embodiment, the canister  1  includes the inner case  3 . On the other hand, in the second embodiment illustrated in  FIG.  5   , a canister  101  does not include the inner case  3 . An adsorbent  140  is inserted from the opening  64  on the lid side of a second chamber  126  and is disposed inside a tube body  71  formed in the vicinity of the atmosphere port  23  in the canister  101 . The tube body  71  includes a straight pipe portion  72  that is a straight pipe portion having a circular cross section, and a tapered portion  73  disposed closer to the lid side than the straight pipe portion  72 . The lid side of the tapered portion  73  is an opening  65  into which the adsorbent  140  is inserted. An inner wall surface of the tapered portion  73  is an inclined surface  95  with which the cross-sectional area in a direction orthogonal to a central axis  81  of the straight pipe portion  72  decreases from the opening  65  side toward an end portion  66  on the opening  65  side of the contact surface  60 . Here, the central axis  81  is a straight line passing through the center of gravity of a circular cross section in each portion of the straight pipe portion  72 . The inclined surface  95  is formed between the opening  65  into which the adsorbent  140  is inserted and the end portion  66  on the opening  65  side of the contact surface  60 . The inclined surface  95  is formed in a tapered shape. 
     2-2. Effects 
     According to the second embodiment described in detail above, the following effects can be obtained in addition to the effects of the first embodiment. 
     (2a) The inclined surface  95  forms the cross-sectional area in the direction orthogonal to the central axis  81  of the straight pipe portion  72 , the cross-sectional area decreasing from the opening  65  side toward the end portion  66  on the opening  65  side of the contact surface  60 . According to such a configuration, an opening end  97  of the opening  65  into which the adsorbent  140  can be inserted is wider than a distal end on an insertion side of the adsorbent  140 . Therefore, when the adsorbent  140  is inserted, the adsorbent  140  can be prevented from coming into contact with the opening end  97  of the opening  65 . Therefore, it is possible to suppress breakage of the adsorbent  140  when the adsorbent  140  is inserted. 
     2-3. Correspondence 
     In the present embodiment, the tube body  71  corresponds to an example of a tubular body. 
     3. Other Embodiments 
     Although the embodiments of the present disclosure have been described above, it is needless to say that the present disclosure is not limited to the above embodiments and can take various forms. 
     (3a) In the second embodiment, the configuration including the straight pipe portion  72  and the tapered portion  73  has been exemplified. However, as illustrated in  FIG.  6   , in a canister  201 , an end portion on the port side of a second chamber  226  may be formed in a tapered shape. In other words, a tube portion  91  defining a truncated cone shaped space in which the adsorbent  4  is disposed is formed at the end on the port side of the second chamber  226 , and the cross-sectional area of the tube portion  91  in a plane orthogonal to a central axis  82  may decrease toward the end portion on the port side. Here, the central axis  82  is a central axis of the truncated cone shaped space formed by the tube portion  91 , and passes through the center of gravity of a cross section of the space. The adsorbent  4  is sandwiched between a filter  211  and a filter  212 . In the present modification, the tube portion  91  corresponds to an example of a tubular body. 
     As illustrated in  FIG.  7   , a canister  301  need not include the filter  211 . Even in this case, the adsorbent  4  is supported by the adsorbent  43  laid in the second chamber  226  so as not to fall to the lid side. 
     As illustrated in  FIG.  8   , when a canister  401  includes an inner case  403 , a filter need not be provided on the lid side of the adsorbent  4 . 
     (3b) In the first embodiment, the configuration has been exemplified in which the opening of the second adsorption chamber  52  for inserting the adsorbent  4  is opened so that the fluid flows in parallel from the lid side to the port side. However, as illustrated in  FIG.  9   , an opening of a second adsorption chamber  552  for inserting the adsorbent  4  may be opened so that the fluid flows in an intersecting direction that is a direction perpendicular to the direction from the lid side toward the port side. In other words, at the end portion on the port side of the second chamber  26 , a tubular portion  92  having a length in the above-described intersecting direction and defining a truncated cone shaped space in which the adsorbent  4  is disposed may be formed. Furthermore, the cross-sectional area of the tube portion  92  in a plane orthogonal to a central axis  83  may decrease from the opening toward the inside of the inner case  3  in the above-described intersecting direction. Here, the central axis  83  is a central axis of the truncated cone shaped space formed by the tube portion  92 , and passes through the center of gravity of a cross section of the space. In the present modification, the tube portion  92  corresponds to an example of a tubular body. 
     (3c) In the second embodiment, the inclined surface  95  configured in a tapered shape having a linear cross-sectional shape has been exemplified. However, the cross-sectional shape of the inclined surface need not be linear. For example, as illustrated in  FIG.  10 A , a portion between the opening  65  into which the adsorbent  140  can be inserted and the end portion on the opening  65  side of the contact surface  60  may be configured to protrude toward the internal space of the second chamber  126 . For example, as illustrated in  FIG.  10 B , a portion between the opening  65  into which the adsorbent  140  can be inserted and the end portion on the opening  65  side of the contact surface  60  may be configured to protrude toward the outside of the second chamber  126 . 
     (3d) In the first embodiment, the configuration in which the inclined surface  93  is formed on the entire surface of the contact surface  60  has been exemplified. In the second embodiment, the configuration in which the inclined surface  95  is formed on the entire surface of the portion between the opening  65  into which the adsorbent  140  can be inserted and the end portion on the opening  65  side of the contact surface  60  has been exemplified. However, the area in which the inclined surface is formed is not limited thereto. The inclined surface only need be formed in at least a partial area of an area from a starting point to the contact surface, the starting point being the opening end of the opening into which the adsorbent can be inserted. The at least partial area of the area from the opening end to the contact surface refers to at least a partial area of the area including the entire region of the contact surface from the opening end. In other words, the at least partial area of the area from the opening end to the contact surface refers to at least a partial area of the area from the opening end to the end portion on the opposite side of the opening of the contact surface. As a modification of the first embodiment, as illustrated in  FIGS.  11 A to  11 C , an inclined surface may be formed in at least a partial area of the contact surface  60 . As illustrated in  FIG.  11 A , a partial area of the contact surface  60  need not be inclined. A central axis  84  may be inclined with respect to the length direction of the inner case  3 . The central axis  84  may be a straight line passing through the center of gravity of the cross section of a main part of the space in which the adsorbent  4  is disposed. As illustrated in  FIG.  11 B , an inclined surface may be formed in an area shorter than the contact surface  60  in the length direction of the inner case  3 . As illustrated in  FIG.  11 C , an inclined surface may be formed in an area longer than the contact surface  60  in the length direction of the inner case  3 . 
     As a modification of the second embodiment, as illustrated in  FIG.  11 D , an inclined surface only need be formed in at least a partial area of a portion between the opening  65  into which the adsorbent  140  is inserted and the end portion on the opening  65  side of the contact surface  60 . A partial area of the portion between the opening  65  into which the adsorbent  140  is inserted and the end portion on the opening  65  side of the contact surface  60  need not be inclined. 
     (3e) In the above embodiments, the configuration in which the adsorbent  4  is an elastically deformable mass of activated carbon has been exemplified. However, the configuration of the adsorbent  4  is not limited thereto. For example, the adsorbent may be elastically undeformable or need not be activated carbon as long as no gap is generated between the adsorbent and the inner case  3 . The adsorbent may have a honeycomb structure. 
     (3f) In the first embodiment, the configuration has been exemplified in which the outer case  2  is indirectly brought into contact with the adsorbent  4  to suppress the removal of the adsorbent  4  in the direction opposite to the direction in which the adsorbent  4  is inserted. However, the outer case  2  may be directly brought into contact with the adsorbent  4  to suppress the removal of the adsorbent  4  in the direction opposite to the direction in which the adsorbent  4  is inserted. 
     (3g) In the above embodiments, the configuration has been exemplified in which the charge port  21 , the purge port  22 , and the atmosphere port  23  are disposed on the same side of the case so as to face the same direction. However, the orientation of these ports is not limited thereto. For example, any one of the ports may be arranged in a direction orthogonal to the other ports. For example, any one of the ports may be disposed on the opposite side of the case from the other ports. 
     (3h) In the first embodiment, the configuration in which the inner case  3  has a round tubular shape and the cross-sectional shape of the inner case  3  is circular has been exemplified. Furthermore, the adsorbent  4  is formed in a truncated cone shape. However, the shape of the inner case  3  is not limited thereto. In addition, the shape of the adsorbent  4  is not limited thereto. For example, the inner case may have a polygonal shape and the adsorbent may be a pyramid or truncated pyramid. 
     In the second embodiment, the configuration in which the straight pipe portion  72  has a circular cross section has been exemplified. However, the shape of the straight pipe portion  72  is not limited thereto. For example, the straight pipe portion may have a polygonal shape. 
     (3i) One or a plurality of functions of one component in the above embodiments may be distributed as a plurality of components, or one or a plurality of functions of a plurality of components may be integrated into one component. A part of the configurations of the above embodiments may be omitted. At least a part of the configurations of the above embodiments may be added to or replaced with another configuration of the above embodiments.