Patent Publication Number: US-2023146496-A1

Title: Mobile toilet

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application under 35 U.S.C. 371 of International Application No. PCT/JP2021/015477, filed Apr. 14, 2021, which claims the priority of Japanese Application No. 2020-073288, filed Apr. 16, 2020, the entire contents of each priority application of which are incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to a mobile toilet. 
     BACKGROUND OF THE DISCLOSURE 
     JP H11-208359 A discloses a conventional mobile toilet. This mobile toilet includes a machine room, a septic tank, and a toilet room unit in a cargo box of a trailer. The toilet room unit includes a plurality of toilet bowls therein. This mobile toilet includes a sewage pump unit below the toilet room unit. The sewage pump unit temporarily stores sewage flowing in from each toilet bowl. The sewage pump unit pumps the temporarily stored sewage to the septic tank. 
     SUMMARY OF THE DISCLOSURE 
     In a conventional mobile toilet, sewage flows down from each toilet bowl to the sewage pump unit disposed below the toilet bowls. In a case where each toilet bowl has a drain trap, there is a possibility that sealing water is drained from the drain trap. When sealing water is drained from the drain trap of the toilet bowl, odor flows back from the sewage pump unit to the toilet room unit. 
     The present disclosure has been made in view of the above conventional circumstances, and an object of the present disclosure is to provide a mobile toilet that can be used well. 
     A mobile toilet according to the present disclosure includes: a vehicle; a sanitary fixture disposed in the vehicle; a drain tank that is disposed in the vehicle and stores sewage discharged from the sanitary fixture; a drain passage that communicates between the sanitary fixture and the drain tank; and a conveyance device provided in the drain passage. The sanitary fixture has a drain trap communicating with an upstream end of the drain passage, and the drain passage passes a position higher than a water level of the drain trap in a water-sealed state, and has a separation portion provided in a position higher than the water level of the drain trap in a water-sealed state. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG.  1    is a vertical sectional view of a mobile toilet according to a first embodiment as viewed from the left. 
         FIG.  2    is a plan view of the mobile toilet according to the first embodiment. 
         FIG.  3    is an enlarged cross-sectional view of a main part according to the first embodiment. 
         FIG.  4    is an enlarged cross-sectional view of a main part according to the first embodiment. 
         FIG.  5    is a perspective view of a part of a toilet room according to the first embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Embodiments of a mobile toilet  1  according to the present disclosure will be described with reference to the drawings. In the following description, as for an up-down direction, a positive direction of the X axis illustrated in  FIG.  1    is an upward direction, and a negative direction of the X axis is a downward direction. As for a left-right direction, a positive direction of the Z axis illustrated in  FIG.  2    is a left direction, and a negative direction of the Z axis is a right direction. As for a front-rear direction, a positive direction of the Y axis illustrated in  FIGS.  1  and  2    is a forward direction, and a negative direction of the Y axis is a rearward direction. 
     As illustrated in  FIGS.  1  to  4   , the mobile toilet  1  includes a trailer  50 , which is a vehicle. The trailer  50  includes a substantially rectangular parallelepiped cargo box  53  which is attached to a chassis  51  and is elongated in the front-rear direction. The trailer  50  is towed by a tractor (not illustrated) or the like. The chassis  51  extends in the front-rear direction. The chassis  51  includes a joining unit  52  at a front end thereof. The joining unit  52  can be joined to the tractor. Two wheels  54  are rotatably attached to a central portion of the chassis  51  in the front-rear direction on each of the left and right sides. The trailer  50  is movable in the front-rear direction. 
     The trailer  50  is provided with an equipment room  10  and a toilet room  20  in the cargo box  53 . The equipment room  10  and the toilet room  20  are provided side by side in the front-rear direction. The mobile toilet  1  includes a ventilation fan F 1  that exhausts air in the equipment room  10  and a ventilation fan F 2  that exhausts air in the toilet room  20 . 
     The equipment room  10  is disposed at a front portion of the cargo box  53 . In each of right and left walls of the equipment room  10 , an opening that allows a person to go in or out of the equipment room  10  is formed. The right wall is provided with a right door  15 A which opens and closes the opening of the right wall, and the left wall is provided with a left door  15 B which opens and closes the opening of the left wall (see  FIG.  2   ). 
     The right door  15 A is opened for allowing a person to go in or out of a right region  10 A in the equipment room  10  through the opening of the right wall. The right region  10 A in the equipment room  10  is mainly used as a work space for installation, maintenance, and the like of a toilet bowl  33 , which will be described later. The left door  15 B is opened for allowing a person to go in or out of a left region  10 B in the equipment room  10  through the opening of the left wall. The left region  10 B in the equipment room  10  is mainly used as a work space for installation, maintenance, and the like of a slop sink  31 , which will be described later. 
     The toilet room  20  is disposed adjacent to and behind the equipment room  10 . The toilet room  20  is surrounded by a first wall  21 , a second wall  22 , a third wall  23 , and a fourth wall  24 . The first wall  21  stands on a right side of the toilet room  20 . The second wall  22  partitions the toilet room  20  and the equipment room  10 , and stands on a front side of the toilet room  20 . The third wall  23  stands on a left side of the toilet room  20 . The fourth wall  24  stands on a rear side of the toilet room  20 . In the toilet room  20 , an entrance  23 A is formed at a rear portion of the third wall  23  through which a person goes in or out of the toilet room  20 . The entrance  23 A is provided with a door  25 . The door  25  has a bellows shape, and is slid in the front-rear direction to open and close the entrance  23 A. 
     As illustrated in  FIGS.  1 ,  2 , and  5   , the mobile toilet  1  includes a plurality of types of sanitary fixtures  31 ,  33 ,  35 , and  37 . The sanitary fixtures are the slop sink  31 , a toilet bowl  33 , a hand wash basin  35 , and a wash basin  37 . The sanitary fixtures are disposed in the toilet room  20 . In addition to the sanitary fixtures  31 ,  33 ,  35 , and  37 , the toilet room  20  includes a first cabinet  41 , a second cabinet  42 , a backrest  43 , handrails  44 A and  44 B, toilet paper holders  45 A and  45 B, a mirror cabinet  46 , a first mirror  47 , a second mirror  48 , and a folding bed  49 . 
     As illustrated in  FIG.  5   , the first cabinet  41  has a box shape, and is attached such that a rear surface thereof is in contact with the first wall  21 . The second cabinet  42  has a box shape slightly larger than the first cabinet  41 , and is attached such that a rear surface thereof is in contact with the second wall  22 . 
     The slop sink  31  is attached to a left side of a front surface of the second cabinet  42 . The front surface of the second cabinet  42  is a surface facing rearward. The toilet bowl  33  is attached to a right side of the front surface of the second cabinet  42 . The backrest  43  is attached to the front surface of the second cabinet  42  and above the toilet bowl  33 . The handrail  44 A and the toilet paper holder  45 A are attached to the front surface of the second cabinet  42  and between the slop sink  31  and the toilet bowl  33 . The handrail  44 A is of a flip-up type. The mirror cabinet  46  is placed on an upper surface of the second cabinet  42 , and is attached such that a rear surface thereof is in contact with the second wall  22 . The mirror cabinet  46  is located above the slop sink  31 . 
     The hand wash basin  35  is attached to an upper part of the first cabinet  41  near the toilet bowl  33  (that is, on the front side of the toilet room  20 ). The toilet paper holder  45 B and the handrail  44 B are attached to a front surface of the first cabinet  41  and below the hand wash basin  35 . The handrail  44 B is a fixed type. The front surface of the first cabinet  41  is a surface facing leftward. The wash basin  37  is attached to an upper part of the first cabinet  41  away from the toilet bowl  33  (that is, on a rear side relative to the hand wash basin  35 ). The first mirror  47  is attached to the first wall  21  above the wash basin  37 . 
     As illustrated in  FIGS.  1  and  2   , the folding bed  49  is attached to the first wall  21  on a rear side relative to the first cabinet  41 . A bed body  49 A of the folding bed  49  is disposed along the first wall  21  when the folding bed  49  is not used, and is disposed parallel to a floor surface when the folding bed  49  is used. The state in which the bed body  49 A is parallel to the floor surface is not illustrated. The second mirror  48  is attached to the fourth wall  24 . A space on the front side of the second mirror  48  in the toilet room  20  is large enough to allow a wheelchair user to change the direction or move when the folding bed is not used. 
     As illustrated in  FIGS.  2  to  4   , the mobile toilet  1  includes a water supply device  60 , a water supply passage  61 , a drain tank  70 , a drain passage  71 , a first conveyance device  73 A, and a second conveyance device  73 B. The water supply device  60  and the drain tank  70  are disposed in the equipment room  10 . In the equipment room  10 , a box  11  is fixed at a central portion in the left-right direction. The box  11  has left and right walls  11 A, an upper wall  11 B, and a rear wall  11 C which are formed of flat plates, and a front side thereof is open. The rear wall  11 C of the box  11  has an opening  11 D through which a hose  71 B, which will be described later, is inserted. A lower end edge of the opening  11 D is located higher than an upper surface of the toilet bowl  33  and an upper surface of the slop sink  31 . The equipment room  10  has a door  13  that opens and closes the front-side opening of the box  11 . 
     The water supply device  60  includes a water supply tank (not illustrated) and a water supply pump (not illustrated). The water supply tank stores clean water to be supplied to each of the sanitary fixtures  31 ,  33 ,  35 , and  37  provided in the toilet room  20 . The water supply tank and the sanitary fixtures  31 ,  33 ,  35 , and  37  communicate with each other through the water supply passage  61 . In the water supply device  60 , when the water supply pump is driven, the clean water stored in the water supply tank flows into the sanitary fixtures  31 ,  33 ,  35 , and  37  through the water supply passage  61 . 
     The drain tank  70  is housed in the box  11  and is disposed at a central portion of the equipment room  10  in the left-right direction. The drain tank  70  has a rectangular parallelepiped shape, and a tubular connection port  70 A is formed on an upper surface thereof. The connection port  70 A is inserted into and connected to a downstream end of the hose  71 B, which will be described later. The drain tank  70  has an opening (not illustrated) formed in the upper surface thereof, and has a lid member that opens and closes the opening. Sewage can be discharged from the drain tank  70  through the opening by removing the lid member. As illustrated in  FIGS.  1  and  3   , a height of the drain tank  70  is higher than the upper surface of the toilet bowl  33  and slightly lower than a height of the second cabinet  42 . 
     As illustrated in  FIGS.  3  and  4   , the drain tank  70  is moved back and forth between a storage position where the drain tank  70  is stored in the box  11  and a drawn-out position where the drain tank  70  is drawn out of the cargo box  53  (outside the storage position) in front of the box  11  by using a pair of slide rails  75 . Specifically, the slide rails  75  are arranged apart from each other in the left-right direction and extend linearly in the front-rear direction, and a fixed rail  75 A of each of the slide rails  75  is fixed to a floor surface of the equipment room  10 , and a movable rail  75 B is fixed to a bottom surface of the drain tank  70 . Each of the slide rails  75  has a lock mechanism (not illustrated) that locks the movable rail  75 B into a state of being pushed in the fixed rail  75 A. By bringing the lock mechanism of each slide rail  75  into a locked state, the drain tank  70  is fixed at the storage position. By bringing the lock mechanism of each slide rail  75  into an unlocked state, the drain tank  70  can be drawn out forward from the storage position to the drawn-out position. At the drawn-out position, half or more of the drain tank  70  in the front-rear direction is drawn out of the cargo box  53 . 
     As illustrated in  FIG.  2   , the drain tank  70  and the sanitary fixtures  31 ,  33 ,  35 , and  37  communicate with each other through the drain passage  71 . Specifically, each of the sanitary fixtures  31 ,  33 ,  35 , and  37  has a drain trap  33 A, and an upstream end of the drain passage  71  communicates with a drain port of each drain trap  33 A (see  FIG.  3   ). 
     The first conveyance device  73 A is provided in the middle of the drain passage  71  communicating with the slop sink  31 . An inflow port of the first conveyance device  73 A is connected to a downstream end of a connection pipe connected to an outlet port of the drain trap of the slop sink  31  (not illustrated). This connection pipe forms the drain passage  71  on an upstream side relative to the first conveyance device  73 A. A drain port of the first conveyance device  73 A is connected to an upstream end of a hose having flexibility (not illustrated). This hose forms the drain passage  71  on a downstream side relative to the first conveyance device  73 A. The first conveyance device  73 A is housed in the second cabinet  42 . The hose connected to the drain port of the first conveyance device  73 A extends from the second cabinet  42  into the equipment room  10 . A portion of this hose that is inserted through the second wall  22  is fixed to the second wall  22 . A downstream end of the hose is connected to an intermediate portion of a hose  71 B connected to a drain port of the second conveyance device  73 B, which will be described later. 
     As illustrated in  FIG.  3   , the second conveyance device  73 B is provided in the middle of the drain passage  71  communicating with the toilet bowl  33 . An inflow port of the second conveyance device  73 B is connected to a downstream end of a connection pipe  71 A connected to an outlet port of the drain trap  33 A of the toilet bowl  33 . This connection pipe  71 A forms the drain passage  71  on an upstream side relative to the second conveyance device  73 B. A drain port of the second conveyance device  73 B is connected to an upstream end of the hose  71 B having flexibility. A downstream end of the hose  71 B is detachably connected to the connection port  70 A of the drain tank  70 . This hose  71 B forms the drain passage  71  on a downstream side relative to the second conveyance device  73 B. The second conveyance device  73 B is housed in the second cabinet  42 . The hose  71 B connected to the drain port of the second conveyance device  73 B extends from the second cabinet  42  into the equipment room  10 . A portion of this hose  71 B that is inserted through the second wall  22  is fixed to the second wall  22 . 
     The drain passages  71  communicating with the hand wash basin  35  and the wash basin  37  merge on an upstream side relative to the second conveyance device  73 B, and the second conveyance device  73 B is provided in the middle of the drain passage  71  on a downstream side relative to the merging portion. An inflow port of the second conveyance device  73 B is connected to a downstream end of a connection pipe connected to the hand wash basin  35  and the wash basin  37 . This connection pipe forms the drain passage  71  on an upstream side relative to the second conveyance device  73 B. 
     As illustrated in  FIG.  3   , the hose  71 B connected to the drain port of the second conveyance device  73 B is inserted into the opening  11 D of the rear wall  11 C of the box  11  fixed to the equipment room  10 , and has a downstream end connected to the connection port  70 A formed on the upper surface of the drain tank  70 . As described above, the hose  71 B connected to the drain port of the second conveyance device  73 B extends upward to a position higher than a water level of the drain trap  33 A in a water-sealed state of the toilet bowl  33  (hereinafter referred to as a “sealing water level WL”) and higher than the upper surface of the drain tank  70 . 
     The hose  71 B connected to the drain port of the second conveyance device  73 B has a length that allows the drain tank  70  to be drawn out to the drawn-out position in a state where the downstream end thereof is connected to the connection port  70 A of the drain tank  70 . Specifically, the hose  71 B has such a length that the hose  71 B is inserted into the opening  11 D formed in the rear wall  11 C of the box  11  while being sufficiently away upwardly from the lower end edge of the opening  11 D when the drain tank  70  is disposed at the storage position, and that the hose  71 B is inserted into the opening  11 D while being away upwardly from the lower end edge of the opening  11 D even when the drain tank  70  is moved to the moved position. That is, an entire length of the hose  71 B is a dimension that does not hinder movement of the drain tank  70  between the storage position and the drawn-out position. When the drain tank  70  is moved between the storage position and the drawn-out position, the hose  71 B always passes a position higher than the sealing water level WL. Similarly, the hose  71 B passes a position higher than the sealing water level WL of the other sanitary fixtures  31 ,  35 , and  37 . 
     The drain tank  70  is provided with a water level sensor (not illustrated). The water level sensor of the drain tank  70  detects a maximum water level of sewage that can be stored in the drain tank  70 . The maximum water level of sewage in the drain tank  70  is a height that is away downwardly by a predetermined distance from a downstream end opening  70 B of the connection port  70 A of the drain tank  70 . 
     In the mobile toilet  1 , when the water level sensor detects that sewage in the drain tank  70  has reached the maximum water level, the water level sensor outputs a full water detection signal to a control unit. Upon receipt of the full water detection signal, the control unit outputs a notification signal to a notification unit (not illustrated), and outputs a drive stop signal to the water supply device  60 , the first conveyance device  73 A, and the second conveyance device  73 B. Upon receipt of the notification signal, the notification unit notifies that the sanitary fixtures  31 ,  33 ,  35 , and  37  are unusable. Upon receipt of the drive stop signal, the water supply device  60 , the first conveyance device  73 A, and the second conveyance device  73 B become unable to be driven. 
     By the notification by the notification unit, a user of the mobile toilet  1  can recognize that the sanitary fixtures are unusable, and a person who manages the mobile toilet  1  performs maintenance such as draining sewage stored in the drain tank  70 . As described above, a water level of the sewage in the drain tank  70  does not exceed the maximum water level, and a water surface of the sewage and the downstream end opening  70 B of the connection port  70 A of the drain tank  70  are always separated by a predetermined distance or more. A spout space X is formed between the water surface of the sewage in the drain tank  70  and the downstream end opening  70 B of the connection port  70 A of the drain tank  70  so that the water surface of the sewage in the drain tank  70  and the downstream end opening  70 B of the connection port  70 A of the drain tank  70  are always separated by the predetermined distance or more, thus forming a separation portion for preventing backflow of the drain passage  71 . This separation portion is provided at a position higher than the sealing water level WL of each of the sanitary fixtures  31 ,  33 ,  35 , and  37 . 
     The sanitary fixtures  31 ,  33 ,  35 , and  37  of the mobile toilet  1  are used as follows. In the case of washing the toilet bowl  33 , an operation unit is operated to open an opening/closing valve provided in the toilet bowl  33 . In response to the operation of the operation unit, a water ejection signal output from the operation unit is input to the control unit, and operation of the water supply pump is started by the control unit. When the water supply pump is operated, clean water flows from the water supply tank into the toilet bowl  33  through the water supply passage  61 . The clean water flowing into the toilet bowl  33  washes the toilet bowl  33  and thereafter flows into the second conveyance device  73 B as sewage. When the sewage flowing into the second conveyance device  73 B reaches a predetermined amount, the control unit drives a pump function, and the sewage flows into the drain tank  70  through the drain passage  71  and is stored in the drain tank  70 . When sewage inside the second conveyance device  73 B is discharged, the control unit stops the pump function of the second conveyance device  73 B. When a predetermined time elapses after the operation of the operation unit, the opening/closing valve of the toilet bowl  33  is closed, and the operation of the water supply pump is stopped by the control unit. In this way, washing of the toilet bowl  33  ends. When washing the slop sink  31 , the water supply pump and the first conveyance device  73 A are driven in a similar manner to perform washing. 
     In the case of ejecting clean water from a water ejection portion provided in the slop sink  31 , when an operation handle provided in the slop sink  31  is operated to open an opening/closing valve, the water supply pump is operated by the control unit, and when the operation handle is operated to close the opening/closing valve, the water supply pump is stopped by the control unit. In this way, clean water can be ejected from the water ejection portion of the slop sink  31 . Sewage flowing into the first conveyance device  73 A from the slop sink  31  flows, by the first conveyance device  73 A, into the drain tank  70  through the drain passage  71  and is stored in the drain tank  70 . When the sewage flowing into the first conveyance device  73 A reaches a predetermined amount, the control unit drives a pump function, and when the sewage inside the first conveyance device  73 A is discharged, the control unit stops the pump function of the first conveyance device  73 A. 
     In the case of ejecting clean water from a water ejection portion provided in the hand wash basin  35  and the wash basin  37 , an opening/closing valve provided in the hand wash basin  35  and the wash basin  37  is opened while a sensor is detecting a user&#39;s hand or the like, and the opening/closing valve provided in the hand wash basin  35  and the wash basin  37  is closed when the sensor no longer detects the user&#39;s hand or the like. While the sensor is detecting a user&#39;s hand or the like, a water ejection signal is continuously input from the operation unit to the control unit, and the operation of the water supply pump is continued by the control unit. In this way, clean water can be ejected from the water ejection portion provided in the hand wash basin  35  and the wash basin  37 . Sewage flowing into the second conveyance device  73 B from the hand wash basin  35  and the wash basin  37  flows, by the second conveyance device  73 B, into the drain tank  70  through the drain passage  71  and is stored in the drain tank  70 . When the sewage flowing into the second conveyance device  73 B reaches a predetermined amount, the control unit drives a pump function, and when the sewage inside the second conveyance device  73 B is discharged, the control unit stops the pump function of the second conveyance device  73 B. 
     As described above, the mobile toilet  1  includes the trailer  50 , the sanitary fixtures  31 ,  33 ,  35 , and  37 , the drain tank  70 , the connection pipe  71 A and the hose  71 B having flexibility, which are the drain passage  71 , the first conveyance device  73 A, and the second conveyance device  73 B. The trailer  50  is movable in the front-rear direction. Each of the sanitary fixtures  31 ,  33 ,  35 , and  37  is disposed in the cargo box  53  of the trailer  50 . The drain tank  70  is disposed in the cargo box  53  of the trailer  50  and stores sewage discharged from each of the sanitary fixtures  31 ,  33 ,  35 , and  37 . The drain passage  71  communicates between each of sanitary fixtures  31 ,  33 ,  35 , and  37  and the drain tank  70 . The first conveyance device  73 A and the second conveyance device  73 B are provided in the middle of the drain passage  71 . Each of the sanitary fixtures  31 ,  33 ,  35 , and  37  has the drain trap  33 A connected to an upstream end of the connection pipe  71 A. The hose  71 B having flexibility passes a position higher than the sealing water level WL of each of the sanitary fixtures  31 ,  33 ,  35 , and  37 , and has the spout space X provided in a position higher than the sealing water level WL. 
     In the mobile toilet  1 , the hose  71 B forming the drain passage  71  which communicates between each of the sanitary fixtures  31 ,  33 ,  35 , and  37  and the drain tank  70  passes a position higher than the sealing water level WL of each of the sanitary fixtures  31 ,  33 ,  35 , and  37 , and has the spout space X provided in a position higher than the sealing water level WL. Therefore, the mobile toilet  1  can prevent sealing water from being drained from the drain trap  33 A of each of the sanitary fixtures  31 ,  33 ,  35 , and  37 , and can prevent odor from flowing back from the first conveyance device  73 A and the second conveyance device  73 B into the cargo box  53  of the trailer  50  in which each of the sanitary fixtures  31 ,  33 ,  35 , and  37  is disposed. 
     Therefore, this mobile toilet  1  can be used well. 
     In the mobile toilet  1 , a half or more of the drain tank  70  in the front-rear direction can be drawn out to the outside of the cargo box  53  (the outside of the storage position (drawn-out position)). Therefore, in the mobile toilet  1 , maintenance such as discharge of sewage from the drain tank  70  and cleaning of the drain tank  70  can be easily performed outside the cargo box  53 . 
     The drain passage  71  on the downstream side relative to the first conveyance device  73 A and the second conveyance device  73 B is formed of the hose  71 B having flexibility. The entire length dimension of the hose  71 B is a dimension that does not hinder movement of the drain tank  70  between the storage position and the drawn-out position. The mobile toilet  1  is thus configured such that the drain tank  70  can be easily moved between the storage position and the drawn-out position while the hose  71 B is connected to the drain tank  70 . After the drain tank  70  is moved to the drawn-out position while keeping the connection of the hose  71 B, the hose  71 B can be removed from the connection port  70 A of the drain tank  70 , and then the drain tank  70  can be completely carried out of the cargo box  53 . By completely carrying out the drain tank  70  to the outside of the cargo box  53 , maintenance such as cleaning of the drain tank  70  can be more easily performed. 
     The present disclosure is not limited to the embodiments described by the above description and drawings, and for example, the following embodiments are also encompassed within the technical scope. 
     (1) In some embodiments, the mobile toilet is configured such that the sanitary fixtures are disposed in the trailer. Not limited to this, the mobile toilet may be configured such that the sanitary fixture is disposed in a luggage room of an automobile.
 
(2) In some embodiments, a plurality of types of sanitary fixtures are provided, and one sanitary fixture is provided for each type. Not limited to this, one or more sanitary fixtures may be provided for each type, and one or more types of sanitary fixtures may be provided.
 
(3) In some embodiments, a water surface of sewage and a downstream end opening of a connection port of a hose of a drain tank are always separated by a predetermined distance or more to form a spout space, and thereby a separation portion for preventing backflow of a drain passage is formed. Not limited to this, the mobile toilet may be configured such that a backflow prevention device such as a vacuum breaker valve is provided in the middle of the drain passage to form the separation portion.
 
(4) In some embodiments, the drain tank can be moved between the storage position and the drawn-out position. Not limited to this, the drain tank may be fixed in the box provided in the cargo box.
 
(5) In some embodiments, the box is fixed in the cargo box. Not limited to this, the box may not be provided and the drain tank may be fixed at a predetermined position in the cargo box.
 
(6) In some embodiments, the hose that forms the drain passage is inserted into the opening formed in the rear wall of the box while being away upwardly from the lower end edge of the opening so that the movement of the drain tank between the storage position and the drawn-out position is not hindered. Not limited to this, the hose may be wound above the drain tank when the drain tank is disposed at the storage position, and the hose above the drain tank may be extended when the drain tank is moved to the drawn-out position.