Patent Publication Number: US-11639763-B2

Title: Expansion pipe joint and incineration ash treatment facility

Description:
TECHNICAL FIELD 
     The present invention relates to an expansion pipe joint that absorbs displacement occurring between connected pipes at a connection portion provided in a location where a conveyed object is conveyed by gravity in a pipe system that conveys powdery and granular conveyed objects, and relates to an incineration ash treatment facility using the expansion pipe joint. 
     BACKGROUND ART 
       FIG.  1    shows a schematic configuration of an incineration ash treatment facility  7  that performs pulverization treatment of incineration ash generated in, for example, a coal fired boiler, a garbage incinerator, and the like. The incineration ash treatment facility  7  shown in  FIG.  1    includes a crusher  75  that finely crushes incineration ash, a conveyor  74  that conveys the incineration ash to the crusher  75 , and a hopper  76  that stores the incineration ash crushed by the crusher  75 . 
     In the incineration ash treatment facility  7  described above, a vibration mill is used as the crusher  75 . Generally, in a vibration mill, a drum (crushing cylinder) is vibrated at high speed to move a pulverizing medium and a material to be pulverized in the drum, so that the material to be pulverized is finely pulverized. Since the crusher  75  vibrates greatly due to its characteristics, an expansion pipe joint  10  that absorbs displacement occurring at a connection portion between an inlet pipe  78  of the crusher  75  and a pipe  77  connected to an outlet of the conveyor  74  is provided at the connection portion. PTLs 1 and 2 disclose this type of expansion pipe joint. 
     The expansion pipe joint described in PTL 1 includes a lap joint inserted in a loose flange, a cylindrical portion inserted in the lap joint, an inner tube whose upper part is swingably connected to the cylindrical portion, an outer tube in which the lower part of the inner tube is inserted, and a bellows that connects the lap joint and the outer tube and covers the outer periphery of the inner tube. 
     The expansion pipe joint described in PTL 2 includes an inner tube (chute) in which a conveyance path is formed on the inner periphery, a cylindrical bellows covering the outer periphery of the inner tube, and bead rings to which both ends of the bellows are fixed. One bead ring is connected to a pipe on an upstream side together with a flange portion of the inner tube, and the other bead ring is connected to a pipe on a downstream side. 
     CITATIONS LIST 
     Patent Literature 
     
         
         PTL 1: JP 2012-117607 A 
         PTL 2: JP 2005-219864 A 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In the expansion pipe joints of PTLs 1 and 2, the inner tube prevents contact between the bellows and the powder or fluid conveyed. However, if the supply of incineration ash to the crusher becomes excessive, the incineration ash that cannot flow out to the crusher remains in the expansion pipe joint, and the incineration ash may enter between the inner tube and the bellows. When the bellows and the high-temperature incineration ash come into contact in this manner, the bellows made from rubber is deteriorated by heat. Further, when vibration is applied to the expansion pipe joint in a state where the bellows and the incineration ash are in contact with each other, the bellows are worn or cracked by friction with the incineration ash. Furthermore, in the crusher, the vibration related to the expansion pipe joint during operation is regular pitching. However, when the operation is stopped, resonance occurs and a tensile force acts on the bellows. As a result, the bellows breaks in a few months, and the bellows is frequently replaced. 
     The present invention has been made in view of the above circumstances, and an object of the present invention is to propose a technique of extending the service life of an expansion pipe joint that is used in a pipe system that conveys a powdery or granular conveyed object and absorbs displacement occurring at a connection portion between pipes. 
     Solution to Problem 
     According to an aspect of the present invention, there is provided an expansion pipe joint that absorbs displacement occurring at a connection portion between an upstream pipe and a downstream pipe where a powdery and/or granular conveyed object is conveyed by gravity. The expansion pipe joint includes an outer tube having a downstream end coupled to the downstream pipe, an inner tube that is inserted into the outer tube and has an upstream end coupled to the upstream pipe, and a closing member having elasticity that is provided between an upstream end of the outer tube and the upstream end of the inner tube so as to close a gap between them. A difference between a position in an axial direction of the upstream end of the outer tube and a position in the axial direction of the upstream end of the inner tube is within a predetermined range so that a bus line of the closing member is inclined from the axial direction. 
     In the above expansion pipe joint, the position in the axial direction of the upstream end of the outer tube and the position in the axial direction of the upstream end of the inner tube may be substantially the same. 
     Further, according to another aspect of the present invention, there is provided an incineration ash treatment facility including a vibration device for treating incineration ash, a pipe for sending the incineration ash to the vibration device, and the expansion pipe joint provided between an outlet of the pipe and an inlet of the vibration device. 
     In the expansion pipe joint and the incineration ash treatment facility, a distance in the axial direction between the closing member of the expansion pipe joint and the downstream end of the outer tube, which is the downstream end of the expansion pipe joint, can be further increased. In this manner, contact between the conveyed object that overflows from the downstream pipe into the expansion pipe joint and the closing member can be avoided, and physical, chemical, and thermal influences that the closing member receives from the conveyed object can be suppressed. As a result, deterioration of the closing member can be suppressed, and the service life of the expansion pipe joint can be extended. 
     Further, in the expansion pipe joint, the outer tube may have an upper flange provided at the upstream end of the outer tube, a lower flange provided at the downstream end of the outer tube and having a smaller inner diameter than the upper flange, and a body having a tapered shape connecting the upper flange and the lower flange. 
     In this manner, the conveyed object overflowing to the expansion pipe joint can be returned to the downstream pipe from the outer tube while a displaceable range in a direction perpendicular to the axial direction of the outer tube relative to the inner tube is ensured. 
     In the expansion pipe joint, a supply pipe for supplying a fluid between the outer tube and the inner tube and/or a discharge pipe for discharging a fluid from between the outer tube and the inner tube may be connected to a portion between the upstream end and a central portion in the axial direction of the outer tube. 
     In this manner, a fluid can be supplied to the air gap between the outer tube and the inner tube through the supply pipe, or a fluid can be discharged from the air gap between the outer tube and the inner tube through the discharge pipe. 
     Further, in the expansion pipe joint, the internal monitoring system may be provided between the upstream end and the central portion in the axial direction of the outer tube. 
     In this manner, it is possible to observe and monitor the gap between the outer tube and the inner tube, which have conventionally been a black box, using the internal monitoring system without disassembling the expansion pipe joint. 
     Further, in the expansion pipe joint, the inner tube or the outer tube may be provided with an intrusion prevention member that closes a gap between the outer tube and the inner tube and prevents the conveyed object from intruding the gap between them. 
     In this manner, the intrusion of the conveyed object into the gap between the outer tube and the inner tube can be prevented. 
     Advantageous Effects of Invention 
     According to the present invention, a technique of extending the service life of an expansion pipe joint that is used in a pipe system that conveys a powdery or granular conveyed object and absorbs displacement occurring at a connection portion between pipes can be proposed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram showing a schematic configuration of an incineration ash treatment facility. 
         FIG.  2    is an end view of a cut portion where an expansion pipe joint according to an embodiment of the present invention is cut along a plane passing through a central axis. 
         FIG.  3    is a view of a closing member as viewed from an axial direction. 
         FIG.  4    is an end view of a cut portion where the expansion pipe joint employing the closing member according to a first modification is cut along a plane passing through a central axis. 
         FIG.  5    is a view of the closing member according to a second modification as viewed from the axial direction. 
         FIG.  6    is an end view of a cut portion where an expansion pipe joint in which a height position of an outer tube is different from an inner tube is cut along a plane passing through a central axis. 
         FIG.  7    is an end view of a cut portion where an expansion pipe joint provided with an intrusion prevention member is cut along a plane passing through a central axis. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Next, an embodiment of the present invention will be described with reference to the drawings.  FIG.  1    is a diagram showing a schematic configuration of an incineration ash treatment facility  7  that employs an expansion pipe joint  10  according to an embodiment of the present invention. The incineration ash treatment facility  7  performs processing of finely crushing incineration ash generated in, for example, a coal fired boiler, a garbage incinerator, and the like. 
     The incineration ash treatment facility  7  shown in  FIG.  1    includes a crusher  75 , a conveyor  74  that conveys the incineration ash to the crusher  75 , and a hopper  76  in which the incineration ash crushed by the crusher  75  is thrown. 
     The conveyor  74  and the crusher  75  are connected by a pipe system that conveys granular or gravel-like incineration ash. This pipe system includes a vibration pipe  78  coupled to an inlet of the crusher  75 , a fixed pipe  77  provided on the upstream side of the vibration pipe  78 , and the expansion pipe joint  10  that connects the fixed pipe  77  and the vibration pipe  78 . Note that, in the description and claims, “upstream” and “downstream” respectively correspond to upstream and downstream in a flow direction of the conveyed object (incineration ash) conveyed by the pipe system. The fixed pipe  77  is an “upstream pipe” when viewed from the expansion pipe joint  10 , and the vibration pipe  78  is a “downstream pipe” when viewed from the expansion pipe joint  10 . 
     The fixed pipe  77  is fixed to a structure (not shown) in which upstream side equipment (for example, the conveyor  74  or equipment used for other coal processing not shown) of the crusher  75  is installed. On the other hand, the vibration pipe  78  vibrates with the vibration of the drum of the crusher  75 . For this reason, displacement due to the vibration of the vibration pipe  78  occurs at the connection portion between the fixed pipe  77  and the vibration pipe  78 . The expansion pipe joint  10  absorbs the displacement occurring at the connection portion between the fixed pipe  77  and the vibration pipe  78 . Note that the expansion pipe joint  10  according to the present invention is applicable also in a case where both the fixed pipe  77  and the vibration pipe  78  are movable. 
     Hereinafter, a detailed configuration of the expansion pipe joint  10  will be described.  FIG.  2    is an end view of a cut portion where the expansion pipe joint  10  according to an embodiment of the present invention is cut along a plane passing through a central axis. Note that, in a state where the vibration pipe  78  is stationary, the expansion pipe joint  10  is a rotating body, and a direction parallel to an extending direction of the axis of rotation of this rotating body is referred to as the “axial direction X” of the expansion pipe joint  10 , and an axis of rotation of the rotating body is referred to as the “central axis” of the expansion pipe joint  10 . The expansion pipe joint  10  is disposed in the pipe system so that the axial direction X and the flow direction of a conveyed object are parallel to each other. 
     The expansion pipe joint  10  shown in  FIG.  2    is configured with an outer tube  21 , an inner tube  22  inserted in the outer tube  21 , and a closing member  24  that closes the space between the outer tube  21  and the inner tube  22 . The inside of the inner tube  22  serves as a conveyance path  20  for a conveyed object in the expansion pipe joint  10 . 
     The outer tube  21  is a metal cylindrical body extending in the axial direction X, and includes an upper flange  21   a  provided at the upstream end of the outer tube, a lower flange  21   b  provided at a downstream end, and a body  21   c  that connects the upper flange  21   a  and the lower flange  21   b.    
     The lower flange  21   b  of the outer tube  21  is coupled to an inlet flange  78   a  provided at an upstream end of the vibration pipe  78  with a bolt or the like. Accordingly, the outer tube  21  is displaced integrally with the vibration pipe  78 . 
     An inner diameter of the upper flange  21   a  is larger than an inner diameter of the lower flange  21   b . The body  21   c  has a tapered shape with a narrowed bottom that smoothly connects the upper flange  21   a  and the lower flange  21   b  having different inner diameters as described above. In the outer tube  21 , a conveyed object can be quickly moved or conveyed from the outer tube  21  to the vibration pipe  78  while a displaceable range in a direction perpendicular to the axial direction X of the outer tube  21  with respect to the inner tube  22  is ensured. 
     The inner tube  22  is a metal cylindrical body extending in the axial direction X, and includes an upper flange  22   a  provided at the upstream end of the inner tube  22  and a body  22   b . The upper flange  22   a  of the inner tube  22  is coupled to an outlet flange  77   a  provided at a downstream end of the fixed pipe  77  with a bolt or the like. 
     A position in the axial direction X of the downstream end of the body  22   b  of the inner tube  22  is slightly upstream of a position in the axial direction X of the lower flange  21   b  of the outer tube  21 . An outer diameter of the body  22   b  of the inner tube  22  is smaller than the inner diameter of the lower flange  21   b  of the outer tube  21 . Accordingly, a gap in a radial direction exists between the inner periphery of the outer tube  21  and the outer periphery of the inner tube  22  inserted substantially concentrically in the outer tube  21 . The size of the gap is preferably larger than the maximum displacement in the horizontal direction of the outer tube  21  with respect to the inner tube  22  at the downstream end of the inner tube  22  in order to avoid interference between the inner tube  22  and the outer tube  21  at the time of displacement. The gap may be an air gap. However, as shown in  FIG.  7   , an intrusion prevention member  25  made from a material that can be elastically deformed and/or follows displacement, such as rubber, may be provided in the gap. The intrusion prevention member  25  may be provided at the downstream end of the inner tube  22  or in the vicinity of the downstream end, or may be provided on the outer tube  21 . Alternatively, the intrusion prevention member  25  may be bridged between the downstream end of the inner tube  22  or the vicinity of the downstream end and the inner periphery of the outer tube  21 . In the example shown in  FIG.  7   , the intrusion prevention member  25  has an annular shape that is continuous or discontinuous in the circumferential direction in plan view, and an inner peripheral edge of the intrusion prevention member  25  is fixed to the downstream end of the inner tube  21 . 
       FIG.  3    is a view of the closing member  24  as viewed from the axial direction X. As shown in  FIGS.  2  and  3   , the closing member  24  has a hollow disk shape in plan view. An inner diameter of the closing member  24  is substantially the same as the inner diameter of the upper flange  22   a  of the inner tube  22 . Further, an outer diameter of the closing member  24  is substantially the same as the outer diameter of the upper flange  21   a  of the outer tube  21 . However, the outer diameter of the closing member  24  may be smaller or larger than the outer diameter of the upper flange  21   a  of the outer tube  21 , as long as the outer diameter is large enough to sandwich an outer edge of the closing member  24  between the upper flange  21   a  of the outer tube  21  and a fixing ring  23 . 
     The closing member  24  is provided between the upper flange  21   a  and the upper flange  22   a  so as to close the gap between the upper flange  21   a  provided at the upstream end of the outer tube  21  and the upper flange  22   a  provided at the upstream end of the inner tube  22 . In the expansion pipe joint  10  configured as described above, the position in the axial direction X of the upper flange  22   a  of the inner tube  22  and the position in the axial direction X of the upper flange  21   a  of the outer tube  21  are substantially the same in a state where the vibration pipe  78  is stationary. 
     In the closing member  24 , an outer mounting portion  241 , an expansion and contraction portion  243 , and an inner mounting portion  242  are integrally formed in this order from the outer peripheral side. 
     The outer mounting portion  241  is sandwiched between the upper flange  21   a  of the outer tube  21  and the fixing ring  23  with gaskets  33  and  34  provided between them, and is coupled to the upper flange  21   a  of the outer tube  21 . The upper flange  21   a , the gaskets  33  and  34 , the outer mounting portion  241  of the closing member  24 , and the fixing ring  23  are fastened by a fastener, such as a bolt (not shown). Note that, in a case where the closing member  24  is formed of a material that is sandwiched between the upper flange  21   a  and the fixing ring  23  and can be compressed and deformed, such as rubber, the gaskets  33  and  34  may be omitted. 
     The inner mounting portion  242  is sandwiched between the upper flange  22   a  of the inner tube  22  and the outlet flange  77   a  of the fixed pipe  77  with gaskets  31  and  32  provided between them, and is coupled to the upper flange  22   a  of the inner tube  22 . The upper flange  22   a , the gaskets  31  and  32 , the inner mounting portion  242  of the closing member  24 , and the outlet flange  77   a  are fastened by a fastener, such as a bolt (not shown). Note that, in a case where the closing member  24  is formed of a material that is sandwiched between the upper flange  22   a  and the outlet flange  77   a  and can be compressed and deformed, such as rubber, the gaskets  31  and  32  may be omitted. 
     The expansion and contraction portion  243  expands and contracts to absorb the displacement in the axial direction X and the radial direction of the outer mounting portion  241  relative to the inner mounting portion  242 . The expansion and contraction portion  243  shown in  FIG.  2    is made from rubber, resin, or cloth, and has a bellows formed in the radial direction. When the conveyed object is at a high temperature as in the present embodiment, the expansion and contraction portion  243  is made from a material having heat resistance. 
     However, the shape of the expansion and contraction portion  243  is not limited to the bellows shape. For example, as shown in  FIG.  4   , if a surface material of the expansion and contraction portion  243  of the closing member  24  ( 24 A) is made from rubber or resin having elasticity, the expansion and contraction portion  243  may be planar. Further, for example, as shown in  FIG.  5   , the expansion and contraction portion  243  of the closing member  24  ( 24 B) may have a spiral core material  29  attached to the surface material made from rubber, resin, or cloth. In this case, the surface material of the expansion and contraction portion  243  may be bent in the radial direction between the core materials  29  to provide a margin for expansion and contraction. Note that the core material  29  may be attached to the surface material in a form, such as a mesh, instead of a spiral. 
     As described above, the incineration ash treatment facility  7  according to the present embodiment includes the crusher  75  that is a vibration device for processing incineration ash, a pipe (the fixed pipe  77 ) that sends the incineration ash to the crusher  75 , and the expansion pipe joint  10  provided between the outlet of the pipe and the inlet (the vibration pipe  78 ) of the crusher  75 . Then, the expansion pipe joint  10  according to the present embodiment is the expansion pipe joint  10  that absorbs displacement occurring at the connection portion between the fixed pipe  77  that is the upstream pipe and the vibration pipe  78  that is the downstream pipe, and includes the outer tube  21  that has a downstream end coupled to the vibration pipe  78 , the inner tube  22  that is inserted into the outer tube  21  and has an upstream end coupled to the fixed pipe  77 , and the closing member  24  having elasticity provided between the upstream end of the outer tube  21  and the upstream end of the inner tube  22  so as to close the gap between them. Then, in a state where the fixed pipe  77  and the vibration pipe  78  are stationary, the position in the axial direction X of the upstream end of the outer tube  21  and the position in the axial direction X of the upstream end of the inner tube  22  are substantially the same. However, at the connection portion between the fixed pipe  77  and the vibration pipe  78  described above, the powdery and/or granular conveyed object is conveyed by gravity. 
     In the expansion pipe joint  10  having the above configuration, the closing member  24  is in a plane orthogonal to the axial direction X of the expansion pipe joint  10 . Furthermore, the closing member  24  is located at the farthest position in the axial direction X from the lower flange  21   b  of the outer tube  21  forming the downstream end of the expansion pipe joint  10 . The closing member  24  and the conveyed object do not contact each other until the conveyed object fills the expansion pipe joint  10 . Therefore, contact between the closing member  24  and the conveyed object and friction caused by such contact can be avoided as much as possible. 
     As described above, the distance in the axial direction X between the closing member  24  and the downstream end of the expansion pipe joint  10  is made larger, so that contact between the conveyed object that overflows from the vibration pipe  78  into the expansion pipe joint  10  and the closing member  24  can be avoided, and physical, chemical, and thermal influences that the closing member  24  receives from the conveyed object can be suppressed. As a result, physical, chemical, and thermal deterioration of the closing member  24  can be suppressed. This makes it possible to extend the service life of the expansion pipe joint  10  as compared with a conventional expansion pipe joint having a bellows provided on an outer side of the inner tube. 
     Note that, from the viewpoint of suppressing the dimension in the axial direction X of the expansion pipe joint  10 , the position in the axial direction X of the upper flange  22   a  of the inner tube  22  of the expansion pipe joint  10  and the position in the axial direction X of the upper flange  21   a  of the outer tube  21  are preferably substantially the same in a state where the vibration pipe  78  is stationary. However, the present invention is not limited to the configuration where the position in the axial direction X of the upper flange  22   a  of the inner tube  22  and the position in the axial direction X of the upper flange  21   a  of the outer tube  21  are strictly the same. That is, as shown in  FIG.  6   , a bus line L of the closing member  24  is inclined by θ° from the axial direction X by a difference between the position in the axial direction X of the upstream end of the outer tube  21  and the position in the axial direction X of the upstream end of the inner tube  22 , and, as long as θ° is within a predetermined range, deterioration of the closing member  24  can be suppressed. Note that the bus line L of the closing member  24  can be defined by a straight line connecting an outer peripheral edge of the inner mounting portion  242  and an inner peripheral portion of the outer mounting portion  241  on one main surface (a lower surface in  FIG.  6   ) of the closing member  24 . 
     The range of the inclination θ° from the axial direction X of the bus line L of the closing member  24  can be determined according to a situation where the expansion pipe joint  10  is installed. For example, as shown in  FIG.  6   , with respect to the overall dimension H 0  in the axial direction X of the expansion pipe joint  10 , in a case where the conveyed object tends to be accumulated up to about ⅗ H 0  from a downstream end surface defining the downstream end of H 0 , a dimension H in the axial direction X of the closing member  24  may be about ⅕ of the overall dimension H 0  in a state where the vibration pipe  78  is stationary. Note that the overall dimension H 0  in the axial direction X of the expansion pipe joint  10  may be the dimension in the axial direction X from the downstream end of the outer tube  21  to the upstream end (the inner mounting portion  242 ) of the closing member  24 . Further, the dimension H in the axial direction X of the closing member  24  may be the dimension in the axial direction X from the downstream end (the outer mounting portion  241 ) to the upstream end (the inner mounting portion  242 ) of the closing member  24 . 
     Further, as described above, since the distance between the closing member  24  and the downstream end of the expansion pipe joint  10  is long in the axial direction X, a gap where no conveyed object is present is maintained between the inner tube  22  and the outer tube  21  of the expansion pipe joint  10  and in the vicinity of the closing member  24 . In view of the above, the expansion pipe joint  10  according to the present embodiment effectively uses this gap. 
     As shown in  FIG.  2   , in the expansion pipe joint  10 , a pipe  28  is connected to a portion between the upstream end and the central portion in the axial direction X of the outer tube  21 . The pipe  28  can function as a supply pipe that supplies a fluid between the outer tube  21  and the inner tube  22  and/or a discharge pipe that discharges a fluid from between the outer tube  21  and the inner tube  22 . The pipe  28  is preferably connected to a position close to the upper flange  21   a  in the body  21   c  of the outer tube  21 . 
     By using the pipe  28  and supplying air between the inner tube  22  and the outer tube  21 , the inside of the expansion pipe joint  10  can be pressurized and clogging of the expansion pipe joint  10  can be eliminated. Further, the pipe  28  is used to supply powder or liquid chemical substances (medicine, and the like) between the inner tube  22  and the outer tube  21 , so that the conveyed object can also be modified or the environment of the conveyance path  20  can also be changed. Furthermore, the pipe  28  is used to introduce and discharge air between the inner tube  22  and the outer tube  21  and in the vicinity of the closing member  24 , so that physical, chemical, and thermal effects that the atmosphere of the closing member  24  has on the closing member  24  can also be suppressed. 
     Further, in the expansion pipe joint  10 , an observation window  27 , which is one of internal monitoring systems, is provided between the upstream end and the central portion in the axial direction X of the outer tube  21 . The observation window  27  is fitted with glass having a function (for example, an antistatic function) for preventing adhesion of a conveyed object, dust, and the like. The observation window  27  is preferably provided at a position close to the upper flange  21   a  in the body  21   c  of the outer tube  21 . 
     By using this observation window  27 , the inside of the expansion pipe joint  10  that has conventionally been a black box can be observed from the outside of the expansion pipe joint  10 . For example, the degree of wear of the closing member  24  can be checked through the observation window  27  without disassembling the expansion pipe joint  10 . Note that the internal monitoring system is not limited to the observation window  27  as long as the internal monitoring system allows a state between the outer tube  21  and the inner tube  22  to be observed and monitored. For example, instead of the observation window  27 , a monitoring system, such as a camera for capturing an image of the state between the outer tube  21  and the inner tube  22  or a temperature detector, may be provided between the upstream end and the central portion in the axial direction X of the outer tube  21 . 
     Although the preferred embodiments of the present invention are described above, modifications of details of the specific structure and/or function details of the above-described embodiments may be included in the present invention without departing from the spirit of the present invention. 
     INDUSTRIAL APPLICABILITY 
     The expansion pipe joint according to the present invention is not limited to the above embodiment, and is widely applicable to an expansion pipe joint that absorbs displacement occurring between connected pipes at a connection portion provided in a location where a conveyed object is conveyed by gravity in a pipe system that conveys powdery and granular conveyed objects. 
     REFERENCE SIGNS LIST 
     
         
           7  incineration ash treatment facility 
           10  expansion pipe joint 
           20  conveyance path 
           21  outer tube 
           21   a  upper flange 
           21   b  lower flange 
           21   c  body 
           22  inner tube 
           22   a  upper flange 
           22   b  body 
           23  fixing ring 
           24  closing member 
           241  outer mounting portion 
           242  inner mounting portion 
           243  expansion and contraction portion 
           27  observation window 
           28  pipe (supply pipe and/or discharge pipe) 
           29  core material 
           25  intrusion prevention member 
           31  to  34  gasket 
           74  conveyor 
           75  crusher 
           76  hopper 
           77  fixed pipe (upstream pipe) 
           77   a  outlet flange 
           78  vibration pipe (downstream pipe) 
           78   a  inlet flange