Patent Publication Number: US-2019183327-A1

Title: Endoscope reprocessor

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of PCT/JP2017/011251 filed on Mar. 21, 2017 and claims benefit of Japanese Application No. 2016-178641 filed in Japan on Sep. 13, 2016, the entire contents of which are incorporated herein by this reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an endoscope reprocessor including a filter arranged in a flow path of liquid. 
     2. Description of the Related Art 
     Reprocessing using a medicinal solution such as an antiseptic solution after use is applied to endoscopes used in the medical field. Further, as disclosed in Japanese Patent Application Laid-Open Publication No. 2010-57752, an endoscope cleaning/disinfecting apparatus that automatically performs reprocessing by arranging an endoscope in a cleaning tank and introducing liquid such as a cleaning solution and a medicinal solution in the cleaning tank is known, for example. 
     The endoscope cleaning/disinfecting apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2010-57752 includes an opening for leading out the liquid accumulated in the cleaning tank, and a circuit for introducing the liquid led out from the opening into a conduit of the endoscope. 
     Further, a feature in which a filter is arranged on an opening part of the cleaning tank in the endoscope cleaning/disinfecting apparatus so that foreign matters existing in the liquid do not enter the conduit of the endoscope and the foreign matters are collected by the filter is known. 
     SUMMARY OF THE INVENTION 
     An endoscope reprocessor according to one aspect of the present invention includes: a treatment tank in which an endoscope is arranged; a drainage conduit including a liquid lead-out port opened in a bottom surface of the treatment tank; an on-off valve arranged in an intermediate position of the drainage conduit; a circulation conduit including a circulation port, the circulation port being opened between the on-off valve and the liquid lead-out port of the drainage conduit and in a position closer to a ground than the liquid lead-out port, the circulation conduit introducing liquid introduced from the circulation port to the treatment tank; a filter arranged in the drainage conduit and covering the circulation port; and a holding portion arranged in the filter or the drainage conduit, the holding portion holding the filter at a position at which the circulation port is covered and liquid that flows into the drainage conduit from an inside of the treatment tank through the circulation port passes through the filter and liquid that flows toward the on-off valve from the inside of the treatment tank through the liquid lead-out port flows along a surface of the filter when the on-off valve is in an open state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view illustrating a configuration of an endoscope reprocessor of a first embodiment; 
         FIG. 2  is a view illustrating a liquid lead-out port, a vertical conduit portion, a circulation port, a filter, and a holding portion of the endoscope reprocessor of the first embodiment in an enlarged manner; 
         FIG. 3  is a schematic diagram illustrating a flow of liquid when the liquid is circulated so as to pass through a treatment tank and a circulation conduit in the endoscope reprocessor of the first embodiment; 
         FIG. 4  is a schematic diagram illustrating a flow of liquid when the liquid in the treatment tank is drained via a drainage conduit in the endoscope reprocessor of the first embodiment; 
         FIG. 5  is a view illustrating a first modification of the first embodiment; 
         FIG. 6  is a view illustrating a second modification of the first embodiment; 
         FIG. 7  is a view illustrating a third modification of the first embodiment; 
         FIG. 8  is a view illustrating a fourth modification of the first embodiment; 
         FIG. 9  is a view illustrating a liquid lead-out port, a vertical conduit portion, a circulation port, a filter, and a holding portion in an endoscope reprocessor of a second embodiment in an enlarged manner; 
         FIG. 10  is a perspective view illustrating the filter and a filter holding cylinder of the second embodiment; 
         FIG. 11  is a cross-sectional view of  FIG. 9  taken along line XI-XI; 
         FIG. 12  is a schematic diagram illustrating a flow of liquid when the liquid is circulated so as to pass through a treatment tank and a circulation conduit in the endoscope reprocessor of the second embodiment; 
         FIG. 13  is a schematic diagram illustrating a flow of liquid when the liquid in the treatment tank is drained via the drainage conduit in the endoscope reprocessor of the second embodiment; 
         FIG. 14  is a view illustrating a first modification of the second embodiment; 
         FIG. 15  is a view illustrating a second modification of the second embodiment; 
         FIG. 16  is a view illustrating a third modification of the second embodiment; and 
         FIG. 17  is a view illustrating a liquid lead-out port, a vertical conduit portion, a circulation port, a filter, and a holding portion of an endoscope reprocessor of a third embodiment in an enlarged manner. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Preferred embodiments of the present invention are described below with reference to the drawings. Note that, in each of the drawings referred to in the description below, the scale is different for each of the components so that each of the components is represented in a size that is recognizable in the drawings. Further, the present invention is not limited only to the number of the components, shapes of the components, size ratios of the components, and relative positional relationships among the respective components illustrated in the drawings. 
     First Embodiment 
     An example of an embodiment of the present invention is described below. An endoscope reprocessor  1  illustrated in  FIG. 1  is an apparatus that applies reprocessing to an endoscope. The reprocessing herein is not particularly limited, and may be any one of rinsing process performed by water, cleaning process for removing contaminations such as organic matters, disinfection process for disabling specified microorganisms, and sterilization process for eliminating or sterilizing all microorganisms, or a combination of the abovementioned processes. 
     Note that, in the description below, expressions “above”, “upper side”, and “upward” refer to a position farther from a ground with respect to an object to be compared and expressions “below”, “lower side”, and “downward” refer to a position closer to the ground with respect to the object to be compared. Further, expressions “high” and “low” in the description below indicate a height relationship along a direction of gravity. 
     The endoscope reprocessor  1  includes a control unit  5 , a power supply unit  6 , a treatment tank  2 , a liquid lead-out port  60 , a drainage conduit  61 , an on-off valve  62 , a circulation conduit  30 , a circulation port  63 , a filter  64 , and a holding portion  65 . 
     The control unit  5  can be configured to include a computing unit (CPU), a storage device (RAM), an auxiliary storage device, an input-output device, a power control device, and the like, and has a configuration that executes a predetermined program in accordance with instructions from a user and controls operation of each part configuring the endoscope reprocessor  1 . The operation of each configuration included in the endoscope reprocessor  1  in the description below is controlled by the control unit  5  even when there are no descriptions in particular. 
     An operation portion  7  and a display unit  8  configure a user interface that performs the exchange of information between the control unit  5  and the user. The operation portion  7  includes operation members that receive operation instructions from the user such as a push-button switch and a touch sensor. The operation instructions from the user are converted to electrical signals by the operation portion  7  and are inputted to the control unit  5 . The operation instructions from the user are instructions for starting the reprocessing, for example. Note that a faun configured so that the operation portion  7  is included in an electronic device separate from a main body portion  1   a  of the endoscope reprocessor  1  and the electronic device performs wired communication or wireless communication with the control unit  5  may be employed. 
     Further, the display unit  8  includes, for example, a display device that displays images and characters, a light-emitting device that emits light, a speaker that emits sound, a vibrator that generates vibration, or combinations of the above. The display unit  8  outputs information from the control unit  5  to the user. Note that a form configured so that the display unit  8  is included in an electronic device separate from the main body portion  1   a  of the endoscope reprocessor  1  and the electronic device performs wired communication or wireless communication with the control unit  5  may be employed. 
     The power supply unit  6  supplies electric power to each part of the endoscope reprocessor  1 . The power supply unit  6  distributes electric power acquired from outside such as a commercial power supply to each part. Note that the power supply unit  6  may include an electric generator and a battery. 
     The treatment tank  2  has a recessed shape having an opening portion, and liquid can be accumulated in the treatment tank  2 . An endoscope (not shown) can be arranged in the treatment tank  2 . A plurality of endoscopes may be arrangeable in the treatment tank  2 . 
     A lid  3  for opening and closing the opening portion of the treatment tank  2  is provided on an upper portion of the treatment tank  2 . When the reprocessing is applied to the endoscope in the treatment tank  2 , the opening portion of the treatment tank  2  is closed by the lid  3 . 
     A medicinal solution nozzle  12 , a cleaning solution nozzle  15 , a liquid lead-out port  60 , a circulation nozzle  14 , and an endoscope connecting portion  16  are provided in the treatment tank  2 . 
     The medicinal solution nozzle  12  is an opening portion communicating with a medicinal solution tank  20  via a medicinal solution conduit  26 . A medicinal solution is accumulated in the medicinal solution tank  20 . 
     The type of the medicinal solution accumulated in the medicinal solution tank  20  is not particularly limited, but the medicinal solution is an antiseptic solution used in the disinfection process or a sterilizing solution used in the sterilization process in the present embodiment as an example. The antiseptic solution or the sterilizing solution includes a peracetic acid aqueous solution. 
     A medicinal solution pump  27  is provided in the medicinal solution conduit  26 . By operating the medicinal solution pump  27 , the medicinal solution in the medicinal solution tank  20  is transferred into the treatment tank  2  via the medicinal solution conduit  26  and the medicinal solution nozzle  12 . 
     Further, in the present embodiment, as an example, the medicinal solution is reusable when the medicinal solution has medical efficacy after being used in the reprocessing. The endoscope reprocessor  1  has a configuration that collects the medicinal solution in the treatment tank  2  and returns the medicinal solution into the medicinal solution tank  20 , although the configuration is not shown. 
     The cleaning solution nozzle  15  is an opening portion communicating with the cleaning solution tank  50  in which the cleaning solution is accumulated via the cleaning solution conduit  51 . The cleaning solution is used in the cleaning process. A cleaning solution pump  52  is provided in the cleaning solution conduit  51 . The cleaning solution pump  52  is electrically connected to the control unit  5 , and the operation of the cleaning solution pump  52  is controlled by the control unit  5 . By operating the cleaning solution pump  52 , the cleaning solution in the cleaning solution tank  50  is transferred into the treatment tank  2 . 
     The liquid lead-out port  60  is an opening portion provided in a lowest location in the treatment tank  2 . The liquid lead-out port  60  is provided in a location in which the liquid in the treatment tank  2  is gathered by gravity. In the present embodiment illustrated in  FIG. 1 , as an example, the liquid lead-out port  60  is opened in a bottom surface of the treatment tank  2 . Note that the liquid lead-out port  60  may be opened in a corner portion between the bottom surface and a side surface. 
     The drainage conduit  61  is connected to the liquid lead-out port  60 . In other words, the drainage conduit  61  has the liquid lead-out port  60  opening to the inside of the treatment tank  2 . 
     The drainage conduit  61  communicates with the liquid lead-out port  60  and a discharge port  66 . The discharge port  66  is a part that discharges the liquid to outside used by the endoscope reprocessor  1 . The discharge port  66  is connected to a drainage appliance for receiving the liquid discharged from the endoscope reprocessor, for example. 
     The on-off valve  62  is arranged in an intermediate position of the drainage conduit  61 . The on-off valve  62  can be at least switched between a closed state in which the drainage conduit  61  is closed and an open state in which the drainage conduit  61  is opened. The on-off valve  62  is electrically connected to the control unit  5 , and the operation of the on-off valve  62  is controlled by the control unit  5 . When the on-off valve  62  is in the closed state, liquid can be accumulated in the treatment tank  2 . Further, when the on-off valve  62  is in the open state, the liquid in the treatment tank  2  is discharged from the discharge port  66  via the liquid lead-out port  60  and the drainage conduit  61 . Note that a pump for facilitating the discharge of the liquid from the treatment tank  2  may be provided between the on-off valve  62  and the discharge port  66  of the drainage conduit  61 . 
     The circulation port  63  is opened between the on-off valve  62  and the liquid lead-out port  60  of the drainage conduit  61  and in a position (low position) closer to the ground than the liquid lead-out port. The circulation conduit  30  is connected to the circulation port  63 . In other words, the circulation conduit  30  includes the circulation port  63 . The circulation conduit  30  is a conduit that introduces the liquid introduced from the circulation port  63  to the treatment tank  2  by the configuration described below. The circulation conduit  30  has a section arranged in a position (high position) farther from the ground than the circulation port  63 . 
     In the present embodiment, as an example, the circulation conduit  30  branches into two conduits, that is, a treatment tank circulation conduit  30   a  and an endoscope connecting conduit  30   b.    
     The treatment tank circulation conduit  30   a  is connected to the circulation nozzle  14 . The circulation nozzle  14  is an opening portion provided in the treatment tank  2 . The circulation nozzle  14  is opened in a position farther from the ground than the liquid lead-out port  60 . Therefore, the treatment tank circulation conduit  30   a  has a section arranged in a position farther from the ground than the circulation port  63 . 
     A treatment tank circulation pump  31   a  is provided in the treatment tank circulation conduit  30   a . The treatment tank circulation pump  31   a  is electrically connected to the control unit  5 , and the operation of the treatment tank circulation pump  31   a  is controlled by the control unit  5 . 
     Further, a three-way valve  42  is provided between the treatment tank circulation pump  31   a  in the treatment tank circulation conduit  30   a  and the circulation nozzle  14 . A water supply conduit  43  is connected to the three-way valve  42 . The three-way valve  42  can be switched between a state in which the circulation nozzle  14  and the treatment tank circulation conduit  30   a  are communicating with each other or a state in which the circulation nozzle  14  and the water supply conduit  43  are communicating with each other. 
     The water supply conduit  43  causes the three-way valve  42  and a water supply source connecting portion  46  to communicate with each other. A water introduction valve  45  that opens and closes the water supply conduit  43  and a water filter  44  that filters water are provided in the water supply conduit  43 . The water supply source connecting portion  46  is connected to a water supply source  49  such as waterworks that transmits water, for example, via a hose and the like. The three-way valve  42  and the water introduction valve  45  are electrically connected to the control unit  5 , and the operation of the three-way valve  42  and the water introduction valve  45  is controlled by the control unit  5 . 
     When liquid is accumulated in the treatment tank  2 , when the operation of the treatment tank circulation pump  31   a  is started while the three-way valve  42  is in a state in which the circulation nozzle  14  and the treatment tank circulation conduit  30   a  are communicating with each other, the liquid in the treatment tank  2  is introduced to the circulation conduit  30  (treatment tank circulation conduit  30   a ) from the liquid lead-out port  60 , and then ejected from the circulation nozzle  14 , to thereby be introduced into the treatment tank  2 . 
     Further, when the water introduction valve  45  is caused to be in the open state while the three-way valve  42  is in a state in which the circulation nozzle  14  and the water supply conduit  43  are communicating with each other, water supplied from the water supply source  49  is introduced into the treatment tank  2  via the circulation nozzle  14 . 
     The endoscope connecting conduit  30   b  is connected to the endoscope connecting portion  16 . The endoscope connecting portion  16  is connected to a pipe sleeve provided in an endoscope arranged in the treatment tank  2 . The endoscope connecting portion  16  may be in a form of being directly connected to the pipe sleeve, or may be in a form of being connected to the pipe sleeve via a connection tube. The endoscope connecting portion  16  is arranged in a position farther from the ground than the liquid lead-out port  60 . Therefore, the endoscope connecting conduit  30   b  has a section arranged in a position farther from the ground than the circulation port  63 . 
     An endoscope circulation pump  31   b  is provided in the endoscope connecting conduit  30   b . The endoscope circulation pump  31   b  is electrically connected to the control unit  5 , and the operation of the endoscope circulation pump  31   b  is controlled by the control unit  5 . 
     When the operation of the endoscope circulation pump  31   b  is started when liquid is accumulated in the treatment tank  2 , the liquid in the treatment tank  2  is introduced to the circulation conduit  30  (endoscope connecting conduit  30   b ) from the liquid lead-out port  60 , and then introduced into the treatment tank  2  via a conduit that communicates with the endoscope connecting portion  16  and the pipe sleeve of the endoscope. 
     As described above, the endoscope reprocessor  1  of the present embodiment has a configuration that introduces the liquid introduced from the liquid lead-out port  60  to the circulation conduit  30  into the treatment tank  2 . 
     The filter  64  is arranged between the on-off valve  62  and the liquid lead-out port  60  of the drainage conduit  61 , and covers the circulation port  63 . The holding portion  65  is arranged in the filter  64  or the drainage conduit  61 , and holds the filter  64  in a position that covers the circulation port  63 . 
     Next, detailed configurations of the liquid lead-out port  60 , the drainage conduit  61 , the circulation port  63 , the circulation conduit  30 , the filter  64 , and the holding portion  65  are described.  FIG. 2  is a view illustrating the liquid lead-out port  60 , the drainage conduit  61 , the circulation port  63 , the filter  64 , and the holding portion  65  in an enlarged manner. 
     For the filter  64  covering the circulation port  63 , a surface exposed in the drainage conduit  61  is referred to as a first surface  64   a  and a surface exposed in the circulation conduit  30  is referred to as a second surface  64   b.    
     As illustrated in  FIG. 2 , the drainage conduit  61  includes a vertical conduit portion  61   a  vertically arranged at least from the liquid lead-out port  60  to the circulation port  63 . Therefore, the circulation port  63  is opened in a vertical wall surface of the drainage conduit  61 . Further, the first surface  64   a  of the filter  64  covering the circulation port  63  is vertically arranged in the drainage conduit  61 . 
     Note that the liquid lead-out port  60  may be covered with a netlike member that prevents attachments and the like of the endoscope from falling into the vertical conduit portion  61   a  of the circulation conduit  30 , although the member is not shown in  FIG. 2 . In the abovementioned case, the netlike member has sparser mesh than the filter  64 . 
     The circulation conduit  30  has an inclined conduit portion  30   c  inclined in a direction away from the ground when the circulation port  63  is a base point. That is, the circulation conduit  30  has a section arranged in a position farther from the ground than the circulation port  63  in the inclined conduit portion  30   c.    
     Next, an effect of the endoscope reprocessor  1  of the present embodiment having the configuration described above is described.  FIG. 3  is a schematic diagram illustrating a flow of liquid when the liquid is circulated so as to pass through the treatment tank  2  and the circulation conduit  30 . Further,  FIG. 4  is a schematic diagram illustrating a flow of liquid when the liquid in the treatment tank  2  is drained via the drainage conduit  61 . 
     The endoscope reprocessor  1  executes the reprocessing using liquid such as a medicinal solution, a cleaning solution, and water for the endoscope arranged in the treatment tank  2  by introducing the liquid into the treatment tank  2 . 
     For example, when the cleaning process of the endoscope is executed, the control unit  5  of the endoscope reprocessor  1  causes the on-off valve  62  to be in the closed state, and then controls the cleaning solution pump  52  and the water introduction valve  45 , to thereby introduce the cleaning solution and the water into the treatment tank  2  by a predetermined volume ratio and accumulate a liquid mixture of the cleaning solution and the water in the treatment tank  2 . 
     Further, the control unit  5  controls the operation of the treatment tank circulation pump  31   a  and the endoscope circulation pump  31   b , to thereby cause the liquid mixture to circulate so as to pass through the treatment tank  2  and the circulation conduit  30 . By the circulation of the liquid mixture, an outer surface of the endoscope and the inside of the conduit are cleaned by the flowing liquid mixture. 
     Further, the control unit  5  stops the circulation of the liquid mixture, and then drains the liquid mixture in the treatment tank  2  via the drainage conduit  61  by causing the on-off valve  62  to be in the open state. 
     When the disinfection process or the sterilization process using a medicinal solution is executed or when the rinsing process using water is executed, the control unit  5  similarly introduces a predetermined volume of the medicinal solution or water into the treatment tank  2 , and then causes the medicinal solution or the water to circulate so as to pass through the treatment tank  2  and the circulation conduit  30 . Then, the medicinal solution or the water in the treatment tank  2  is drained via the drainage conduit  61 . 
     As described above, when the reprocessing is performed, the endoscope reprocessor  1  of the present embodiment executes circulation operation that causes liquid to circulate so as to pass through the treatment tank  2  and the circulation conduit  30 , and then executes drainage operation that drains the liquid in the treatment tank  2  via the drainage conduit  61 . 
       FIG. 3  indicates a flow of liquid when the circulation operation is being executed by arrows F. As illustrated in  FIG. 3 , during the circulation operation, liquid  70  accumulated in the treatment tank  2  flows so as to flow into the vertical conduit portion  61   a  of the drainage conduit  61  from the liquid lead-out port  60 , passes through the filter  64 , and then returns into the treatment tank  2  through the circulation port  63  and the circulation conduit  30 . 
     During the circulation operation, the liquid passes through the filter  64  from the first surface  64   a  toward the second surface  64   b . Therefore, a foreign matter  71  detached from the endoscope and floating in the liquid  70  is collected by the filter  64  and adheres to the first surface  64   a  of the filter  64 . The foreign matter  71  is biomedical tissue, mucus, and the like that has adhered to the endoscope when the endoscope is used, for example. 
     As described above, by arranging the filter  64  in a flow path of the liquid  70  during the circulation operation, the foreign matter  71  existing in the liquid  70  is collected, and the foreign matter is prevented from entering the circulation conduit  30  in which the pump is arranged or the conduit of the endoscope. 
       FIG. 4  indicates a flow of liquid during the execution of the drainage operation by arrows F. A state in which the liquid is accumulated in the treatment tank  2  is obtained at a time point immediately before the drainage operation starts. As described above, the drainage operation is executed after the circulation operation. Further, the circulation conduit  30  is communicating with the liquid lead-out port  60  of the treatment tank  2  via the vertical conduit portion  61   a  and the circulation port  63 . Therefore, at a time point immediately before the drainage operation starts, a state in which the liquid  70  is accumulated not only in the treatment tank  2  but also in the circulation conduit  30  is obtained as illustrated in  FIG. 4 . 
     Further, when the drainage operation starts by causing the on-off valve  62  to be in the open state, the liquid  70  accumulated in the treatment tank  2  is drained through the drainage conduit  61  and the on-off valve  62 . Further, the circulation conduit  30  has a section arranged in a position farther from the ground than the circulation port  63  such as the inclined conduit portion  30   c . Therefore, when the drainage operation starts, at least a part of the liquid  70  accumulated in the circulation conduit  30  flows toward the circulation port  63 , and is drained through the circulation port  63 , the drainage conduit  61 , and the on-off valve  62 . 
     Now, when the flow of the liquid  70  near the filter  64  during the drainage operation is focused on, during the drainage operation, a first flow F 1  in which the liquid  70  passes through the filter  64  from the second surface  64   b  toward the first surface  64   a  from the inside of the circulation conduit  30  and then flows into the vertical conduit portion  61   a , and a second flow F 2  in which the liquid  70  flows into the vertical conduit portion  61   a  from the treatment tank  2  and then flows down to the lower side along the first surface  64   a  of the filter  64  are generated. The first flow F 1  and the second flow F 2  are indicated by an arrow F 1  and an arrow F 2  in  FIG. 4 . 
     The first flow F 1  in the liquid  70  generated during the drainage operation applies force to the foreign matter  71  adhering to the first surface  64   a  of the filter  64  in a direction in which the foreign matter  71  is detached from the first surface  64   a  into the vertical conduit portion  61   a . Therefore, by the first flow F 1  in the liquid  70 , the foreign matter  71  adhering to the first surface  64   a  of the filter  64  is placed in a state that is detached or easily detached from the first surface  64   a.    
     Further, the second flow F 2  in the liquid  70  generated during the drainage operation causes the foreign matter  71  adhering to the first surface  64   a  of the filter  64  to be detached from the first surface  64   a  by applying shear force to the foreign matter  71 . Further, the second flow F 2  in the liquid  70  washes away the foreign matter  71  detached from the first surface  64   a  to the on-off valve  62  and discharges the foreign matter  71  from the inside of the vertical conduit portion  61   a.    
     As described above, the endoscope reprocessor  1  of the present embodiment detaches the foreign matter  71  collected by the filter  64  from the filter  64  and discharges the foreign matter  71  with the liquid  70  when the drainage operation of the liquid  70  accumulated in the treatment tank  2  is executed. That is, the endoscope reprocessor  1  of the present embodiment can automatically remove the foreign matter  71  from the filter  64 . As a result, the frequency of cleaning work of the filter  64  manually performed by the user can be reduced, for example. 
     Note that, in the present embodiment, the section from the liquid lead-out port  60  to the circulation port  63  in the drainage conduit  61  is vertically arranged, but the arrangement of the section from the liquid lead-out port  60  to the circulation port  63  in the drainage conduit  61  is not limited to the present embodiment. For example, as in a first modification illustrated in  FIG. 5 , the section from the liquid lead-out port  60  to the circulation port  63  in the drainage conduit  61  may be arranged so as to be tilted with respect to the direction of gravity. Further, as in the first modification illustrated in  FIG. 5 , the liquid lead-out port  60  may be provided in a corner portion at which the bottom surface and the side surface of the treatment tank  2  intersect with each other. 
     Further, a cross-sectional area of the flow path of the circulation conduit  30  does not necessarily need to be constant, and may be different for each predetermined section. For example, as in a second modification illustrated in  FIG. 6 , an enlarged diameter portion  30   d  having a cross-sectional area that is expanded as compared to cross-sectional areas of other sections of the circulation conduit  30  may be provided in the inclined conduit portion  30   c  of the circulation conduit  30 . By providing the enlarged diameter portion  30   d  in the inclined conduit portion  30   c  of the circulation conduit  30 , a volume of the liquid accumulated in the circulation conduit  30  at a time point in which the drainage operation starts can be increased. Therefore, in the second modification, the volume of the liquid flowing in the direction in which the foreign matter  71  is detached from the filter  64  in the drainage operation can be increased, and hence the foreign matter can be removed from the filter  64  in a more reliable manner. 
     Further, as in a third modification illustrated in  FIG. 7 , an enlarged diameter portion  30   e  that expands a cross-sectional area of the flow path may be provided in a portion at which the circulation conduit  30  is connected to the circulation port  63 . By providing the enlarged diameter portion  30   e  in the portion at which the circulation conduit  30  is connected to the circulation port  63 , an area by which the liquid passes through the filter  64  during the circulation operation expands, and a flow rate of the liquid passing through the filter  64  can be increased. 
     Further, as in a fourth modification illustrated in  FIG. 8 , a reduced diameter portion  30   f  that reduces the cross-sectional area of the flow path may be provided in a portion at which the circulation conduit  30  is connected to the circulation port  63 . By providing the reduced diameter portion  30   f  in the portion at which the circulation conduit  30  is connected to the circulation port  63 , a flow velocity of the liquid flowing in a direction in which the foreign matter  71  is detached from the filter  64  in the drainage operation can be increased, and hence the foreign matter can be removed from the filter  64  in a more reliable manner. 
     Second Embodiment 
     A second embodiment of the present invention is described below. Only differences from the first embodiment are described below, components similar to components in the first embodiment are denoted by the same reference characters, and description of such components is omitted as appropriate.  FIG. 9  is a view illustrating the liquid lead-out port  60 , the vertical conduit portion  61   a , the circulation port  63 , the filter  64 , and the holding portion  65  of the endoscope reprocessor  1  of the present embodiment in an enlarged manner.  FIG. 10  is a perspective view illustrating the filter  64  and a filter holding cylinder  67 .  FIG. 11  is a cross-sectional view of  FIG. 9  taken along line XI-XI. 
     The present embodiment is different from the first embodiment in terms of the configuration of the filter  64  and the holding portion  65 . The filter  64  of the present embodiment has a cylindrical shape, both ends of which are opened. In the filter  64 , a pair of end portions  64   c  face upward and downward in a state in which the filter  64  is inserted from the liquid lead-out port  60  into the vertical conduit portion  61   a . Therefore, when the filter  64  having a cylindrical shape is inserted in the vertical conduit portion  61   a , the end portion  64   c  facing upward is opened toward the liquid lead-out port  60 . Further, when the filter  64  is inserted in the vertical conduit portion  61   a , the end portion  64   c  facing downward is opened toward the on-off valve  62 . The filter  64  has a cylindrical shape, and hence the openings at the pair of end portions  64   c  are connected by a space passing through the filter  64 . Therefore, in the drainage operation in which the on-off valve  62  is caused to be in the open state and the liquid in the treatment tank  2  is drained via the drainage conduit  61 , the liquid in the treatment tank  2  is drained without being filtered by the filter  64 . 
     Further, when the filter  64  is inserted in the vertical conduit portion  61   a , the filter  64  covers the circulation port  63 . In the present embodiment, an inner circumferential surface of the filter  64  having a cylindrical shape is the first surface  64   a  and an outer circumferential surface of the filter  64  is the second surface  64   b.    
     The filter  64  is held by the filter holding cylinder  67  having a cylindrical shape. The filter holding cylinder  67  is a member for maintaining a shape of the filter  64  having a cylindrical shape. Therefore, when the shape of the filter  64  can be maintained by a rigidity of the filter  64 , the filter holding cylinder  67  is unnecessary. 
     The filter holding cylinder  67  of the present embodiment has a cylindrical shape, both ends of which are opened, and the filter  64  is arranged on the outer circumferential surface or the inner circumferential surface. In the present embodiment that is illustrated, as an example, the filter  64  is sticking to the inner circumferential surface of the filter holding cylinder  67 , but the present invention is not limited to the configuration. For example, the filter  64  and the filter holding cylinder  67  may be integrally molded. 
     The filter holding cylinder  67  can be inserted from the liquid lead-out port  60  into the vertical conduit portion  61   a . When the filter holding cylinder  67  is inserted in the vertical conduit portion  61   a , an upper end-portion opening  67   a  provided in the end portion facing upward is opened toward the liquid lead-out port  60 . Further, when the filter holding cylinder  67  is inserted in the vertical conduit portion  61   a , a lower end-portion opening  67   f  provided in the end portion facing downward is opened toward the on-off valve  62 . 
     Further, one or a plurality of side-surface portion openings  67   b  that pass through the filter holding cylinder  67  from outer circumferential surface to the inner circumferential surface are formed in the filter holding cylinder  67 . The side-surface portion openings  67   b  are arranged in positions that overlap with the filter  64 . Further, when the filter holding cylinder  67  is inserted in the vertical conduit portion  61   a , the side-surface portion openings  67   b  are arranged in positions that are opened toward the circulation port  63 . 
     Seal members  67   c  that come into close contact with the inner circumferential surface of the vertical conduit portion  61   a  are provided above and below a region of the outer circumferential surface of the filter holding cylinder  67  in which the side-surface portion openings  67   b  are formed. By the pair of seal members  67   c , the flow path of the liquid between an inner side of the filter holding cylinder  67  and the circulation port  63  is only limited to routes that pass through the side-surface portion openings  67   b . That is, in the present embodiment, all the liquid passing through the filter  64  passes through the side-surface portion openings  67   b.    
     Further, in  FIG. 9 , the filter holding cylinder  67  is positioned in the vertical conduit portion  61   a  when a lower end portion  67   d  abuts against the on-off valve  62  also serving as the holding portion  65 . That is, in the present embodiment, a part of the on-off valve  62  exposed to the inside of the vertical conduit portion  61   a  configures the holding portion  65  that holds the filter  64  in a position that covers the circulation port  63 . Further, the filter holding cylinder  67  has a flange shape that is caught in the liquid lead-out port, and hence serves as the holding portion  65 . In  FIG. 9 , the holding portion is formed on both the filter and the drainage conduit, but the holding portion may be formed on one of the filter and the drainage conduit. 
     As illustrated in  FIG. 10 , a handle  67   e  is provided on an upper end portion of the filter holding cylinder  67  so that the filter holding cylinder  67  is easily inserted into and removed from the vertical conduit portion  61   a . Further, in the present embodiment, the filter  64  has a cylindrical shape that is inserted in the vertical conduit portion  61   a , and hence the filter  64  can be turned about a vertical axis in the vertical conduit portion  61   a  as illustrated in  FIG. 11  when the user operates the handle  67   e.    
       FIG. 12  indicates a flow of the liquid  70  when the circulation operation of the endoscope reprocessor  1  of the present embodiment is executed by arrows F. As illustrated in  FIG. 12 , during the circulation operation, the liquid  70  accumulated in the treatment tank  2  flows into the vertical conduit portion  61   a  of the drainage conduit  61  from the liquid lead-out port  60 , and flows into a space in the filter  64  from the opening in the end portion  64   c  facing upward of the filter  64  having a cylindrical shape. Further, the liquid  70  flowing in a space in the filter  64  flows so as to pass through the filter  64  from the first surface  64   a  that is the inner circumferential surface of the filter  64  toward the second surface  64   b  that is the outer circumferential surface, and then return into the treatment tank  2  through the circulation port  63  and the circulation conduit  30 . Therefore, the foreign matter  71  detached from the endoscope and floating in the liquid  70  is collected by the filter  64  and adheres to the first surface  64   a  of the filter  64 . 
       FIG. 13  illustrates a flow of the liquid when the drainage operation of the endoscope reprocessor  1  of the present embodiment is executed. When the drainage operation starts by causing the on-off valve  62  is to be in the open state, the liquid  70  accumulated in the treatment tank  2  is drained through the drainage conduit  61  and the on-off valve  62 . Further, when the drainage operation starts, at least a part of the liquid  70  accumulated in the circulation conduit  30  flows toward the circulation port  63 , and is drained through the circulation port  63 , the filter  64 , and the on-off valve  62 . 
     Now, when the flow of the liquid  70  near the filter  64  during the drainage operation is focused on, during the drainage operation, a first flow F 1  in which the liquid  70  passes through the filter  64  from the second surface  64   b  toward the first surface  64   a  from the inside of the circulation conduit  30  and flows into a space in the filter  64 , and a second flow F 2  in which the liquid  70  flows into a space in the filter  64  from the inside of the treatment tank  2  and then flows down to the lower side along the first surface  64   a  of the filter  64  are generated. 
     As in the first embodiment, the first flow F 1  in the liquid  70  generated during the drainage operation applies force to the foreign matter  71  adhering to the first surface  64   a  of the filter  64  in a direction in which the foreign matter  71  is detached from the first surface  64   a  into an inner space in the filter  64 . Therefore, by the first flow F 1  in the liquid  70 , the foreign matter  71  adhering to the first surface  64   a  of the filter  64  is placed in a state that is detached or easily detached from the first surface  64   a.    
     Further, the second flow F 2  in the liquid  70  generated during the drainage operation causes the foreign matter  71  to be detached from the first surface  64   a  by applying shear force to the foreign matter  71  adhering to the first surface  64   a  of the filter  64 . Further, the second flow F 2  in the liquid  70  washes away the foreign matter  71  detached from the first surface  64   a  to the on-off valve  62  and discharges the foreign matter  71  from the inside of the vertical conduit portion  61   a.    
     As described above, the endoscope reprocessor  1  of the present embodiment detaches the foreign matter  71  collected by the filter  64  from the filter  64  and discharges the foreign matter  71  with the liquid  70  when the drainage operation of the liquid  70  accumulated in the treatment tank  2  is executed. That is, the endoscope reprocessor  1  of the present embodiment can automatically remove the foreign matter  71  from the filter  64 . As a result, the frequency of cleaning work of the filter  64  manually performed by the user can be reduced, for example. 
     Further, in the present embodiment, the filter  64  can be turned about the vertical axis in the vertical conduit portion  61   a . When the filter  64  has a cylindrical shape as in the present embodiment, regions at which the liquid  70  passes through the filter  64  in the circulation operation tend to be regions close to the circulation port  63 . Therefore, in the present embodiment, when the circulation operation is performed, the foreign matter  71  tends to adhere to partial regions of the inner circumferential surface (first surface  64   a ) of the filter  64  in a circumferential direction about the vertical axis in a concentrated manner. 
     As described above, the foreign matter  71  mainly adhering to partial regions of the inner circumferential surface of the filter  64  is detached and discharged by performing the drainage operation. However, when the foreign matter is a foreign matter difficult to be detached such as mucus, there is a possibility that a part of the foreign matter  71  remains adhering to the filter  64  even when the drainage operation is performed. 
     In the present embodiment, by turning the filter  64  about the vertical axis by 90 degrees or 180 degrees, for example, in the vertical conduit portion  61   a  after executing the reprocessing a predetermined number of times, a region to which the adherence of the foreign matter  71  has been light in the reprocessing executed before can be brought near the circulation port  63 . 
     Therefore, in the present embodiment, even when a state in which the foreign matter  71  remains adhering to the filter  64  occurs, a reduction in a flow rate due to the existence of the foreign matter  71  in the circulation operation performed later can be suppressed or prevented by turning the filter  64 . Further, in the abovementioned case, there is a possibility that the foreign matter  71  that remains adhering to regions distant from the circulation port  63  of the filter  64  is detached by the second flow F 2  in the liquid  70  in the drainage operation that is performed later. Therefore, in the endoscope reprocessor  1  of the present embodiment, by regularly turning the filter  64 , the frequency of cleaning work of the filter  64  manually performed by the user can be reduced, for example. 
     Note that the shape of the filter  64  only needs to be a cylindrical shape, and is not limited to a circularly cylindrical shape. For example, as illustrated in  FIG. 14  as a first modification, the filter  64  may have a cylindrical shape, an external form of which is a square when seen from above in a state in which the filter  64  is inserted in the vertical conduit portion  61   a . Further, the filter  64  may have a cylindrical shape, an external form of which is a polygon such as a triangle or a hexagon when seen from above in a state in which the filter  64  is inserted in the vertical conduit portion  61   a.    
     Further, the endoscope reprocessor  1  may have a configuration in which the filter  64  inserted in the vertical conduit portion  61   a  is turned about the vertical axis. For example, as illustrated in  FIG. 15  as a second modification, the endoscope reprocessor  1  may include a ring-shaped ultrasound motor  68  arranged along the inner circumferential surface of the vertical conduit portion  61   a , and may have a configuration in which the filter  64  or the filter holding cylinder  67  is turned by the ultrasound motor  68 . 
     Further, for example, as illustrated in  FIG. 16  as a third modification, the filter  64  or the filter holding cylinder  67  may include a water wheel  69  that rotates about the vertical axis in accordance with the flow of the liquid  70  flowing in the vertical conduit portion  61   a  in the vertical direction. In the modification illustrated in  FIG. 16 , blades of the water wheel  69  are fixed to the filter holding cylinder  67 , and the filter holding cylinder  67  and the filter  64  turn about the vertical axis every time the liquid flows in the vertical conduit portion  61   a.    
     Further, the modifications illustrated in  FIG. 5  to  FIG. 9  in the first embodiment can be also applied to the endoscope reprocessor  1  of the present embodiment. 
     Third Embodiment 
     A third embodiment of the present invention is described below. Only differences from the first embodiment are described below, components similar to components in the first embodiment are denoted by the same reference characters, and description of such components is omitted as appropriate.  FIG. 17  is a view illustrating the liquid lead-out port  60 , the vertical conduit portion  61   a , the circulation port  63 , the filter  64 , and the holding portion  65  of the endoscope reprocessor  1  of the present embodiment in an enlarged manner. 
     As illustrated in  FIG. 17 , the endoscope reprocessor  1  of the present embodiment is different from the first embodiment in that the endoscope reprocessor  1  of the present embodiment includes a bypass conduit  72  and a bypass conduit on-off valve  73 . 
     The bypass conduit  72  is a conduit communicating with the inside of the treatment tank  2  and the inside of the circulation conduit  30 . Note that the bypass conduit  72  is opened to the bottom surface of the treatment tank  2  in the illustrated embodiment as an example, but the bypass conduit  72  may be opened to a section, which is above the circulation port  63  of the drainage conduit  61  and not covered with the filter  64 . 
     The bypass conduit on-off valve  73  is arranged in the bypass conduit  72 . The bypass conduit on-off valve  73  can be switched between a closed state in which the bypass conduit  72  is closed, and an open state in which the bypass conduit  72  is opened. The bypass conduit on-off valve  73  is electrically connected to the control unit  5 , and the operation of the on-off valve  62  is controlled by the control unit  5 . 
     The control unit  5  causes the bypass conduit on-off valve  73  to be in the open state only when the drainage operation is executed, and causes the bypass conduit on-off valve  73  to be in a closed state otherwise. 
     In the endoscope reprocessor  1  of the present embodiment, by causing the bypass conduit on-off valve  73  to be in the open state when the drainage operation is executed, a part of the liquid  70  accumulated in the treatment tank  2  can be caused to flow into the circulation conduit  30  in the drainage operation. That is, in the present embodiment, a part of the liquid  70  accumulated in the treatment tank  2  can be caused to flow so as to pass through the filter  64  from the second surface  64   b  toward the first surface  64   a  in the drainage operation. 
     Therefore, in the endoscope reprocessor  1  of the present embodiment, the volume of the liquid flowing in a direction in which the foreign matter  71  is detached from the filter  64  in the drainage operation can be increased, and hence the foreign matter can be removed from the filter  64  in a more reliable manner. 
     Note that the modifications illustrated in  FIG. 5  to  FIG. 9  in the first embodiment can be also applied to the endoscope reprocessor  1  of the present embodiment. Further, the endoscope reprocessor  1  of the present embodiment may include the filter  64  having a cylindrical shape as in the second embodiment. In addition, when the endoscope reprocessor  1  of the present embodiment includes the filter  64  having a cylindrical shape similar to the filter  64  having a cylindrical shape in the second embodiment, the modifications illustrated in  FIG. 14  to  FIG. 16  in the second embodiment can be applied. 
     The present invention is not limited to the abovementioned embodiments and can be changed, as appropriate, within a scope not deviated from the spirit or the concept of the present invention that can be read from the claims and the entire specification, and an endoscope reprocessor changed as above is also included in the technical scope of the present invention.