JP6881680B2 - Flow path switching device - Google Patents

Description

The present invention relates to a flow path switching device for switching a flow path of a liquid.

For example, in a liquid chromatograph mass analyzer that combines a liquid chromatograph and a mass analyzer, each component in the liquid sample is separated and separated in the column by supplying the liquid sample to the column of the liquid chromatograph. Each component is introduced into a mass analyzer (see, for example, Patent Document 1 below).

In some devices of this type, a flow path switching device for switching the flow path is provided in the flow path of the liquid sample introduced from the liquid chromatograph into the mass spectrometer. The flow path switching device is used, for example, to switch and guide a liquid sample supplied from a liquid chromatograph to an ionization probe or drain in a mass spectrometer.

Japanese Unexamined Patent Publication No. 2006-162256

As the flow path switching device as described above, for example, a diverter valve can be used. As a configuration of the diverter valve, a configuration in which a stator and a rotor are provided in a hollow main body housing can be considered.

The stator is a plate-shaped member fixed in the main body housing. On the other hand, the rotor is a rotatable plate-shaped member that comes into contact with the stator, and the flow path can be switched by rotating the rotor with respect to the stator. An opening is formed in the main body housing, and the opening is closed by the lid member by attaching the lid member to the main body housing in a state where the stator and the rotor are housed in the main body housing.

Since the stator and rotor are in sliding contact with each other, they are consumed with use. Therefore, it is necessary to periodically remove the lid member from the main body housing and replace the stator and rotor.

The lid member is fixed to the main body housing by, for example, tightening a plurality of screws. Therefore, when replacing the stator and rotor, after loosening a plurality of screws and removing the lid member, the stator and rotor in the main body housing are replaced through the opening. After the replacement, the lid member covers the opening and the plurality of screws are tightened again to attach the lid member to the main body housing.

When attaching the lid member to the main body housing, it is necessary to tighten each screw evenly. If the tightening amount of each screw is not uniform, the surface pressure of the contact surface between the stator and the rotor becomes non-uniform, so that a gap is created between the starter and the rotor, and liquid leakage may occur from the gap. .. In addition, if some of the screws are excessively tightened, the stator and rotor may be damaged.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flow path switching device capable of attaching a lid member to a main body housing by uniformly tightening a plurality of screws.

(1) The flow path switching device according to the present invention is a flow path switching device for switching a liquid flow path, and is a main body housing, a flow path switching mechanism, a lid member, a plurality of screws, and a stopper mechanism. And. The main body housing is hollow and has an opening. The flow path switching mechanism is housed in the main body housing and switches the flow path. The lid member is removable from the main body housing and closes the opening of the main body housing. The plurality of screws fix the lid member to the main body housing. The stopper mechanism limits the rotation range of the tool for rotating the plurality of screws.

The flow path switching mechanism has a plate-shaped stator fixed in the main body housing and a rotatable plate-shaped rotor that abuts on the stator, and by rotating the rotor with respect to the stator. Switch the flow path. The stopper mechanism limits the rotation range of the tool when rotating each screw within a predetermined angle range.

According to such a configuration, the rotation range of the tool when rotating each screw is limited within a predetermined angle range by the stopper mechanism, so that it is possible to prevent only some screws from being excessively tightened. Can be done. Therefore, the lid member can be attached to the main body housing by tightening the plurality of screws evenly.

(2) The plurality of screws may each have hexagonal holes for inserting the end portion of the hexagon wrench as the tool. In this case, the predetermined angle range may be 60 ° or more.

According to such a configuration, each screw can be rotated by using a hexagon wrench as a tool, and the lid member can be attached to the main body housing. By setting the predetermined angle range to 60 ° or more, after rotating each screw by 60 ° or more, change the direction (angle) at which the end of the hexagon wrench is inserted into the hexagonal hole of each screw and rotate again. The work of making it work can be done smoothly.

(3) The difference in the predetermined angle range corresponding to each screw is preferably within ± 5 ° from each other.

According to such a configuration, when each screw is tightened in order, the variation in the tightening amount of each screw is suppressed within an angle range of ± 5 °. Therefore, the plurality of screws can be tightened more evenly.

(4) The flow path switching device may further include a display unit for displaying the switching state of the flow path by the flow path switching device. In this case, at least a part of the stopper mechanism may be composed of a mounting surface to which the display unit is mounted.

According to such a configuration, the rotation range of the tool when rotating the screw is set within a predetermined angle range by using the mounting surface of the display unit for displaying the switching state of the flow path by the flow path switching device. Can be restricted. Therefore, since it is not necessary to provide a separate member as the stopper mechanism, the manufacturing cost can be reduced.

(5) The flow path switching device may further include an exterior member that houses the main body housing inside. In this case, at least a part of the stopper mechanism may be formed by the inner surface of the exterior member.

According to such a configuration, the rotation range of the tool when rotating the screw can be limited to a predetermined angle range by utilizing the inner surface of the exterior member that houses the main body housing inside. Therefore, since it is not necessary to provide a separate member as the stopper mechanism, the manufacturing cost can be reduced.

According to the present invention, it is possible to prevent only a part of the screws from being excessively tightened, so that a plurality of screws can be tightened evenly to attach the lid member to the main body housing.

It is the schematic which showed the structure of the liquid chromatograph mass spectrometer which concerns on one Embodiment of this invention. It is a figure which showed the flow path in a liquid chromatograph mass spectrometer, and shows the state which a sample component flows from a liquid chromatograph to a mass spectrometer. It is a figure which showed the state which switched the flow path of the flow path switching device from the state of FIG. It is a perspective view which showed the structure of the flow path switching device. It is sectional drawing of the flow path switching device along the line AA of FIG. It is the schematic plan view for demonstrating the mode at the time of tightening a 1st screw. It is the schematic plan view for demonstrating the mode at the time of tightening a 2nd screw. It is the schematic plan view for demonstrating the mode at the time of tightening a 3rd screw.

1. 1. Configuration of Liquid Chromatograph Mass Spectrometer FIG. 1 is a schematic view showing the configuration of a liquid chromatograph mass spectrometer 1 according to an embodiment of the present invention. The liquid chromatograph mass spectrometer 1 includes a liquid chromatograph (LC) 2 that separates components in a sample, and a mass spectrometer (MS) 3 that performs mass spectrometry on the sample components separated by the liquid chromatograph 2. It is a device that combines.

Although not shown, in the liquid chromatograph 2, the mobile phase stored in the storage tank is sent toward the column at a constant flow rate. Then, the sample is injected into the mobile phase, and the sample components contained in the mobile phase are temporally separated in the column. The separated sample component is sent to the mass spectrometer 3 via the pipe 4. The mass spectrometer 3 includes a housing 5, a flow path switching device 6, a mass spectrometer 7, a drainage tray 8, a drainage sensor 9, pipes 10, 11 and the like.

The flow path switching device 6 is installed in the housing 5. The sample component from the liquid chromatograph 2 flows into the flow path switching device 6 via the pipe 4. Further, the sample component that has flowed into the flow path switching device 6 from the liquid chromatograph 2 flows into the mass spectrometer 7 via the pipe 10. As described above, the flow path switching device 6 is a device for switching the flow path of the sample (liquid) by interposing the flow path of the sample from the liquid chromatograph 2 to the mass spectrometer 7. The detailed configuration of the flow path switching device 6 will be described later.

The mass spectrometer 7 is housed in the housing 5. In the mass spectrometer 7, the introduced sample component is ionized, and the ions are separated according to the mass-to-charge ratio (m / z). Then, the separated ions are detected by a detector (not shown), and mass spectrometry is performed.

The drainage tray 8 is arranged in the housing 5 at a position away from the flow path switching device 6. The pipe 11 is fixed to the housing 5 so as to extend from the flow path switching device 6 over the drainage tray 8. The drainage sensor 9 is provided in the drainage tray 8. The drainage sensor 9 detects the sample drained in the drainage tray 8. The drainage sensor 9 and the drainage tray 8 constitute the drainage section 12.

When the sample is analyzed by the liquid chromatograph mass spectrometer 1, the sample components separated by the liquid chromatograph 2 flow into the mass spectrometer 7 via the pipe 4, the flow path switching device 6, and the pipe 10. .. At this time, if a sample leaks from the flow path switching device 6, the leaked sample is discharged to the drainage tray 8 via the pipe 11. In this case, the sample discharged to the drainage tray 8 is detected by the drainage sensor 9.

The flow path in the liquid chromatograph mass spectrometer 1 at this time is shown in FIG. FIG. 2 is a diagram showing a flow path in the liquid chromatograph mass spectrometer 1, showing a state in which sample components flow from the liquid chromatograph 2 to the mass spectrometer 7. As shown in FIG. 2, the flow path switching device 6 has six ports a to f. Each of the ports a to f corresponds to the opening 241A of the lid member 24, which will be described later.

The port a of the flow path switching device 6 communicates with the liquid chromatograph 2. That is, the pipe 4 (see FIG. 1) is connected to the port a of the flow path switching device 6. The port b of the flow path switching device 6 communicates with the mass spectrometer 7. That is, the pipe 10 (see FIG. 1) is connected to the port b of the flow path switching device 6.

The port c of the flow path switching device 6 communicates with the standard sample introduction unit 15. The standard sample introduction unit 15 introduces the standard sample (STD) into the flow path switching device 6. The port d and the port f of the flow path switching device 6 communicate with the drain flow path.

In the state of FIG. 2, the port a and the port b of the flow path switching device 6 communicate with each other, and the port c and the port d communicate with each other. Therefore, as described above, the sample component separated by the liquid chromatograph 2 flows into the mass spectrometer 7 via the flow path switching device 6. Further, the standard sample sent out from the standard sample introduction unit 15 is discharged to the drain flow path via the flow path switching device 6.

FIG. 3 is a diagram showing a state in which the flow path of the flow path switching device 6 is switched from the state of FIG. In this state, the port a and the port f of the flow path switching device 6 communicate with each other, and the port b and the port c communicate with each other. Therefore, the standard sample sent out from the standard sample introduction unit 15 flows into the mass spectrometry unit 7 via the flow path switching device 6. Further, in the liquid chromatograph 2, a mobile phase containing no sample is flowed, and this mobile phase is discharged to the drain flow path via the flow path switching device 6.

In this way, in the liquid chromatograph mass spectrometer 1, the flow path is appropriately switched by the flow path switching device 6, and the analysis operation is performed. As will be described later, the flow path switching device 6 includes a mechanism for switching the flow path (flow path switching mechanism) and the like, and therefore requires regular maintenance work. In the liquid chromatograph mass spectrometer 1, the flow path switching device 6 is configured as follows so that the work on the flow path switching device 6 can be smoothly performed.

2. Specific configuration of the flow path switching device FIG. 4 is a perspective view showing the configuration of the flow path switching device 6. FIG. 5 is a cross-sectional view of the flow path switching device 6 along the line AA of FIG. Note that FIG. 4 shows a state in which a part of the housing 5 is omitted. The flow path switching device 6 in the present embodiment includes a main body housing 21, a rotating mechanism 22, a flow path switching mechanism 23, a lid member 24, and the like.

The main body housing 21 is fixed to the housing 5. The main body housing 21 is a hollow member extending in the vertical direction. The main body housing 21 is formed with a recess 21A and a through hole 21B. The recess 21A is recessed downward from the upper surface of the main body housing 21, and the upper end thereof constitutes an opening of the main body housing 21. The through hole 21B penetrates the lower end portion of the main body housing 21 in the vertical direction and communicates with the recess 21A.

As shown in FIG. 5, the rotation mechanism 22 is inserted into the main body housing 21 from below the main body housing 21. The rotating mechanism 22 includes a motor shaft 26, a rotating body 27, and a coupling 28.

The motor shaft 26 is arranged below the main body housing 21 in the housing 5. The motor shaft 26 is formed in a rod shape extending in the vertical direction. The motor shaft 26 is rotatable about an axis extending in the vertical direction. The motor shaft 26 rotates by applying a driving force from a motor (not shown).

The rotating body 27 is arranged above the motor shaft 26, and a part thereof is arranged in the main body housing 21. The rotating body 27 includes a shaft portion 29 and a holding portion 30. The shaft portion 29 is formed in a rod shape extending in the vertical direction. The diameter of the shaft portion 29 is slightly smaller than the diameter of the through hole 21B of the main body housing 21. The holding portion 30 is provided at the upper end portion of the shaft portion 29. The holding portion 30 is formed in a substantially columnar shape. The diameter of the holding portion 30 is larger than the diameter of the shaft portion 29 and slightly smaller than the diameter of the recess 21A of the main body housing 21.

The rotating body 27 is rotatably held in the main body housing 21 with the shaft portion 29 inserted through the through hole 21B. In this state, the upper portion of the shaft portion 29 and the holding portion 30 are housed in the main body housing 21 (inside the recess 21A), and the lower portion of the shaft portion 29 is arranged outside (lower) of the main body housing 21.

The coupling 28 connects the shaft portion 29 of the rotating body 27 and the motor shaft 26. The upper end of the coupling 28 is connected to the lower end of the shaft 29, and the lower end of the coupling 28 is connected to the upper end of the motor shaft 26. As a result, when the motor shaft 26 rotates, the rotating body 27 rotates together with the coupling 28.

The flow path switching mechanism 23 is a mechanism for switching the flow path in the flow path switching device 6. The flow path switching mechanism 23 is housed in the main body housing 21 (inside the recess 21A), and is arranged above the holding portion 30 of the rotating body 27. The flow path switching mechanism 23 includes a rotor 31 and a stator 32.

The rotor 31 is arranged above the holding portion 30 of the rotating body 27. The rotor 31 is formed in a disk shape. The rotor 31 is formed with a plurality of grooves (not shown) extending in the circumferential direction. The rotor 31 is detachably attached to the upper surface of the holding portion 30 so that its central axis coincides with the central axis of the holding portion 30.

The stator 32 is arranged above the rotor 31. The stator 32 is formed in a disk shape. The stator 32 is formed with a plurality of openings (not shown) arranged at intervals in the circumferential direction. The stator 32 is in contact with the upper surface of the rotor 31 in a state of being fixed at a fixed position in the main body housing 21 so that its central axis coincides with the central axis of the rotor 31.

With such a configuration, when the rotating body 27 rotates, the rotor 31 rotates together with the rotating body 27. On the other hand, the stator 32 is held in the main body housing 21 in a state where the rotating body 27 does not rotate and maintains a constant orientation even when the rotating body 27 rotates. As a result, the relative positions of the plurality of grooves provided in the rotor 31 and the plurality of openings provided in the stator 32 are appropriately changed, and the flow path in the flow path switching device 6 is switched.

The lid member 24 is formed in a disk shape having an outer diameter larger than the inner diameter of the opening (upper end of the recess 21A) of the main body housing 21. The lid member 24 is removable from the main body housing 21. The lid member 24 is attached to the main body housing 21 along the horizontal plane to close the opening of the main body housing 21. The central portion 241 of the lid member 24 forms a protruding portion that projects upward. A plurality of openings 241A are formed in the central portion 241 of the lid member 24, and a groove 242A and a drainage port 242B are formed in the outer edge portion 242 of the lid member 24.

Each opening 241A penetrates the central portion 241 of the lid member 24. Each opening 241A communicates with a plurality of openings formed in the stator 32. Each opening 241A corresponds to each of the ports a to f (see FIGS. 2 and 3) described above. Note that FIG. 5 shows a state in which a part of the openings 241A is sealed by the sealing member 35. As shown in FIG. 5, of the plurality of openings 241A of the lid member 24, the unused openings 241A may be sealed by the sealing member 35.

The groove 242A is an annular recess formed on the upper surface of the outer edge portion 242 of the lid member 24 and extending in the circumferential direction. The groove 242A is recessed in a V-shaped cross section downward from the upper surface of the outer edge portion 242. The drainage port 242B penetrates the outer edge portion 242 in the vertical direction so as to communicate with the groove 242A.

A pipe joint 40 is provided in the housing 5. The pipe joint 40 includes a vertical portion 41 and a horizontal portion 42, which are formed in a tubular shape, respectively. The vertical portion 41 extends in the vertical direction and is close to the outer peripheral surface of the main body housing 21. The upper end of the vertical portion 41 communicates with the drainage port 242B. The horizontal portion 42 extends continuously from the lower end portion of the vertical portion 41 in the horizontal direction (direction away from the main body housing 21). The tip of the horizontal portion 42 is connected to one end of the pipe 11 (see FIG. 1).

3. 3. Attaching the lid member to the main body housing When attaching the lid member 24 to the main body housing 21, the operator places the lid member 24 on the upper surface of the main body housing 21 so that the lid member 24 is along the horizontal plane. After that, as shown in FIG. 4, the operator fixes the lid member 24 to the main body housing 21 by inserting the plurality of screws 50 into the lid member 24 from above and tightening each of them to the main body housing 21.

In the present embodiment, three screws 50 are provided at equal intervals in the circumferential direction with respect to the center of the lid member 24. That is, the angular distance between the mounting positions of the screws 50 with respect to the center of the lid member 24 is constant (about 120 °). If the plurality of screws 50 provided at equal intervals are tightened evenly, the lid member 24 can be fixed horizontally to the main body housing 21, so that the contact surface between the stator 32 and the rotor 31 Surface pressure becomes uniform.

A hexagonal hole 51 is formed in the head of each screw 50, for example. When tightening or loosening each screw 50, the end of a hexagon wrench 52 (see FIGS. 6A to 6C) as a tool is inserted into the hexagonal hole 51 of each screw 50. The hexagon wrench 52 is a rod-shaped member having a hexagonal cross section, and has an L-shaped bent or curved shape.

Hereinafter, modes for tightening the three screws 50 (first screw 50A, second screw 50B, and third screw 50C) will be specifically described.

FIG. 6A is a schematic plan view for explaining an embodiment when tightening the first screw 50A. When the end of the hexagon wrench 52 is inserted into the hexagonal hole 51 of the first screw 50A and the hexagon wrench 52 is rotated, the first stopper member 53A and the second stopper member 53B are on the trajectory of the hexagon wrench 52. It is provided. The first stopper member 53A and the second stopper member 53B are rod-shaped members attached to the housing 5, respectively, and extend in the vertical direction.

When the hexagon wrench 52 is rotated in the state of FIG. 6A, the hexagon wrench 52 comes into contact with the stopper members 53A and 53B, so that the rotation range θ1 of the hexagon wrench 52 is limited to a predetermined angle range. In this way, the stopper members 53A and 53B function as a stopper mechanism 53 for limiting the rotation range θ1 of the hexagon wrench 52.

FIG. 6B is a schematic plan view for explaining an embodiment when tightening the second screw 50B. When the end of the hexagon wrench 52 is inserted into the hexagonal hole 51 of the second screw 50B and the hexagon wrench 52 is rotated, the mounting surface 54A of the display portion 54 and the exterior member 55 are on the trajectory of the hexagon wrench 52. The inner surface 55A of is provided.

The display unit 54 is for displaying the switching state of the flow path by the flow path switching device 6, and is composed of, for example, an LED display. The display unit 54 electrically displays whether the flow path switched by the flow path switching device 6 is in the state of FIG. 2 or FIG. The operator can easily confirm the state of the flow path (state of FIG. 2 or 3) by looking at the display of the display unit 54. The mounting surface 54A to which the display portion 54 is mounted is composed of a part of the sheet metal forming the housing 5. The mounting surface 54A extends in the vertical direction in the vicinity of the main body housing 21.

The exterior member 55 is a decorative member that covers the outside of the housing 5. The exterior member 55 is formed in a hollow shape, and the main body housing 21 and the like are housed therein. A part of the inner surface 55A of the exterior member 55 extends in the vertical direction in the vicinity of the main body housing 21.

When the hexagon wrench 52 is rotated in the state of FIG. 6B, the hexagon wrench 52 comes into contact with the mounting surface 54A of the display unit 54 and the inner surface 55A of the exterior member 55, so that the rotation range θ2 of the hexagon wrench 52 is within a predetermined angle range. Limited to. In this way, the mounting surface 54A to which the display unit 54 is mounted and the inner surface 55A of the exterior member 55 each function as a stopper mechanism 53 for limiting the rotation range θ2 of the hexagon wrench 52.

FIG. 6C is a schematic plan view for explaining an embodiment when tightening the third screw 50C. When the end of the hexagon wrench 52 is inserted into the hexagonal hole 51 of the third screw 50C and the hexagon wrench 52 is rotated, the surface of the display portion 54 and the inner surface of the exterior member 55 are on the trajectory of the hexagon wrench 52. 55A is provided.

When the hexagon wrench 52 is rotated in the state of FIG. 6C, the hexagon wrench 52 comes into contact with the surface of the display unit 54 and the inner surface 55A of the exterior member 55, so that the rotation range θ3 of the hexagon wrench 52 is limited to a predetermined angle range. Will be done. In this way, the surface of the display unit 54 and the inner surface 55A of the exterior member 55 each function as a stopper mechanism 53 for limiting the rotation range θ3 of the hexagon wrench 52.

4. Action effect (1) In the present embodiment, the rotation range θ1 to θ3 of the hexagon wrench 52 when rotating each screw 50 (first screw 50A, second screw 50B, and third screw 50C) is determined by the stopper mechanism 53. Since it is limited to the angle range of, it is possible to prevent only a part of the screws 50 from being excessively tightened. Therefore, the lid member 24 can be attached to the main body housing 21 by evenly tightening the plurality of screws 50.

(2) As shown in FIG. 6B, when the second screw 50B is rotated, the second screw 50B uses the mounting surface 54A of the display unit 54 for displaying the switching state of the flow path by the flow path switching device 6. The rotation range θ2 of the hexagon wrench 52 when rotating the screw 50B can be limited within a predetermined angle range. Therefore, since it is not necessary to separately provide a member as the stopper mechanism 53, the manufacturing cost can be reduced.

(3) Further, as shown in FIGS. 6B and 6C, when rotating the second screw 50B and the third screw 50C, respectively, the inner surface 55A of the exterior member 55 accommodating the main body housing 21 is used. The rotation ranges θ2 and θ3 of the hexagon wrench 52 when rotating the screws 50B and 50C can be limited within a predetermined angle range. Therefore, since it is not necessary to separately provide a member as the stopper mechanism 53, the manufacturing cost can be reduced.

(4) The rotation range θ1 to θ3 of the hexagon wrench 52 when rotating each screw 50 (first screw 50A, second screw 50B, and third screw 50C) is a predetermined value of 60 ° or more (for example, about 70 °). It is preferably limited within the angular range. As a result, the lid member 24 can be attached to the main body housing 21 by rotating each screw 50 using the hexagon wrench 52 as a tool. By setting a predetermined angle range to 60 ° or more, after rotating each screw 50 by 60 ° or more, the direction (angle) for inserting the end of the hexagon wrench 52 into the hexagonal hole 51 of each screw 50 is set. The work of changing and rotating again can be performed smoothly.

(5) The difference in the predetermined angle range (rotation range θ1 to θ3) corresponding to each screw (first screw 50A, second screw 50B, and third screw 50C) is preferably within ± 5 ° from each other. .. As a result, when the screws 50 are tightened in order, the variation in the tightening amount of the screws 50 can be suppressed within an angle range of ± 5 °. Therefore, the plurality of screws 50 can be tightened more evenly.

5. Deformation Example In the above embodiment, the case where the number of screws 50 for attaching the lid member 24 to the main body housing 21 is three has been described. However, the number of screws 50 is not limited to three, and may be two or four or more. Even in such a case, the rotation range of the tool when rotating each screw 50 may be limited by the stopper mechanism 53.

The tool for rotating each screw 50 is not limited to the hexagon wrench 52, and any other tool can be used. Therefore, each screw 50 is not limited to the configuration in which the hexagonal hole 51 for inserting the end portion of the hexagon wrench 52 is formed.

The flow path switching device 6 is not limited to a device for switching the flow path of the sample, and can be used as a device for switching the flow path of any other liquid. Therefore, the flow path switching device 6 is not limited to the configuration provided in the mass spectrometer 3 of the liquid chromatograph mass spectrometer 1, and may be configured in another analyzer, or may have a configuration other than the analyzer. It may have a configuration provided in the device.

1 Liquid chromatograph mass spectrometer 2 Liquid chromatograph 3 Mass spectrometer 6 Flow path switching device 21 Main body housing 21A Recess 21B Through hole 23 Flow path switching mechanism 24 Lid member 31 Rotor 32 Stator 50 Screw 50A First screw 50B Second screw 50C 3rd screw 51 Hexagonal hole 52 Hexagonal wrench 53 Stopper mechanism 53A 1st stopper member 53B 2nd stopper member 54 Display part 54A Mounting surface 55 Exterior member 55A Inner surface θ1 to θ3 Rotation range

Claims (5)

A flow path switching device for switching the flow path of a liquid.
A hollow body housing with an opening and
A flow path switching mechanism housed in the main body housing for switching the flow path,
A lid member that is removable from the main body housing and closes the opening of the main body housing,
A plurality of screws for fixing the lid member to the main body housing,
A stopper mechanism for limiting the rotation range of the tool for rotating the plurality of screws is provided.
The flow path switching mechanism has a plate-shaped stator fixed in the main body housing and a rotatable plate-shaped rotor that abuts on the stator, and by rotating the rotor with respect to the stator. It switches the flow path,
The stopper mechanism is a flow path switching device characterized in that the rotation range of the tool when rotating each screw is limited to a predetermined angle range. Hexagonal holes for inserting the ends of the hexagonal wrench as the tool are formed in each of the plurality of screws.
The flow path switching device according to claim 1, wherein the predetermined angle range is 60 ° or more. The flow path switching device according to claim 1, wherein the difference in the predetermined angle range corresponding to each screw is within ± 5 ° from each other. A display unit for displaying the switching state of the flow path by the flow path switching device is further provided.
The flow path switching device according to claim 1, wherein at least a part of the stopper mechanism is composed of a mounting surface to which the display unit is mounted. Further provided with an exterior member for accommodating the main body housing inside,
The flow path switching device according to claim 1, wherein at least a part of the stopper mechanism is composed of an inner surface of the exterior member.

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