Flow passage switch, system, and flow passage switching method

Abstract

To provide a device that can automatically replace air in a balloon of a catheter with fluid, and has high operability.SOLUTION: A flow passage switch comprises: a first cylinder; a first seal to be slid in the first cylinder; an air flow passage connected to the first cylinder on one side of the first seal; a first bypass flow passage connected to the air flow passage, connected to the first cylinder, and to be opened and closed by the first seal; a second cylinder; a second seal to be slid in the second cylinder in conjunction with the first seal; a fluid passage connected to the second cylinder on one side of the second seal; a second bypass flow passage connected to the fluid passage, connected to the second cylinder, and to be opened and closed by the second seal; and a catheter connection flow passage connected to the first cylinder on the other side of the first seal, connected to the second cylinder, and to be opened and closed by the second seal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a flow path switcher, a system, and a flow path switching method. [Background technology]

[0002] Patent Documents 1 and 2 disclose a medical stopcock and a fluid administration device that are connected to a catheter, respectively. Patent Document 3 discloses a stopcock drive device that switches flow paths using an actuator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 07-100212 [Patent Document 2] Japanese Patent Application Publication No. 09-173470 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-048940 Summary of the Invention [Problem to be solved by the invention]

[0004] A balloon catheter inserted into the body has a balloon that expands and contracts depending on the amount of expansion medium injected. When using a balloon catheter, the air inside the balloon must be evacuated and replaced with a fluid such as a contrast agent or saline to reduce the risk of air embolism in the event of a burst.

[0005] In a typical procedure, a syringe filled with fluid is connected to a balloon catheter, and negative pressure is applied to create a negative pressure inside the balloon to achieve this. To automate this process, a method can be considered in which the air suction line and the fluid supply line are separated.

[0006] When the air suction line and fluid supply line are separated, a valve is required to prevent the fluid from being sucked in during air suction and to prevent the fluid from reaching the suction side during fluid supply. Therefore, it is conceivable to construct a device using a valve driven by an actuator, such as a solenoid valve. However, such a device would be large in weight and size, potentially reducing operability. Furthermore, a cover would be required when used in a clean area. Therefore, it is desirable to construct a device using a passive element that does not require an actuator. However, in such a device, the flow direction of suction by negative pressure and replacement by fluid would be opposite, making a simple check valve inappropriate.

[0007] An object of the present disclosure is to provide a highly maneuverable device that can automatically replace the air in a catheter balloon with a fluid. [Means for solving the problem]

[0008] Some aspects of the present disclosure are set forth below.

[0009] [1] A flow path switcher that switches a flow path between air suctioned from a balloon attached to a catheter and a fluid supplied to the balloon, A first cylinder; a first seal that slides within the first cylinder; an air flow path connected to one side of the first seal of the first cylinder; a first bypass flow path connected to the air flow path and connected to the first cylinder and opened and closed by the first seal; A second cylinder; a second seal that slides within the second cylinder in conjunction with the first seal; a fluid flow path connected to one side of the second seal of the second cylinder; a second bypass flow path connected to the fluid flow path and connected to the second cylinder and opened and closed by the second seal; a catheter connection flow path connected to the first cylinder on the other side of the first seal, and connected to the second cylinder and opened and closed by the second seal; A flow path switcher comprising:

[0010] [2] The flow path switch described in [1] further comprises a connecting member that connects the first seal and the second seal through one open end of the first cylinder and one open end of the second cylinder.

[0011] [3] When the first seal moves to a first open position to open the first bypass flow path, the second seal moves to a second closed position in conjunction with the first seal to close the second bypass flow path and the catheter connection flow path, A flow path switcher as described in [1] or [2], wherein when the second seal moves to a second open position that opens the second bypass flow path and the catheter connection flow path, the first seal moves in conjunction with the second seal to a first closed position that closes the first bypass flow path.

[0012] [4] The flow path switcher described in [3], wherein the second cylinder has a stopper that limits the range of movement of the second seal in the direction from the second closed position toward the second open position.

[0013] [5] a third seal that slides within the second cylinder in conjunction with the second seal; a fourth seal separated from the second seal by the third seal and sliding within the second cylinder; Further provided with the fluid flow path is connected to the second cylinder on the opposite side of the fourth seal from the third seal; A flow path switcher described in any one of [1] to [4], wherein the second bypass flow path and the catheter connection flow path are connected to the second cylinder on the opposite side of the third seal from the fourth seal.

[0014] [6] When the second seal moves to a second closed position in which the second seal interlocks with the first seal to close the second bypass flow path and the catheter connection flow path, the third seal moves in conjunction with the second seal, and the fourth seal is pushed and moved by the third seal; when the third seal is pushed and moved by the fourth seal, the second seal moves in conjunction with the third seal to a second open position that opens the second bypass flow path and the catheter connection flow path; [5] A flow path switcher according to the present invention, wherein when the fourth seal moves independently away from the third seal, the third seal does not move and the second seal remains in the second open position.

[0015] [7] [1] to [6], and a flow path switch according to any one of [1] to [6]. a negative pressure source connected to the air flow path; a pressure increasing / decompressing device connected to the fluid flow path; A system comprising:

[0016] [8] connecting a negative pressure source to an air flow path connected to one side of a first seal of a first cylinder that slides within the first cylinder; a pressure increasing / depressurizing device connected to a fluid flow path connected to one side of a second seal of a second cylinder, the second seal sliding within the second cylinder in conjunction with the first seal; connecting a catheter having a balloon attached to a catheter connection channel connected to the other side of the first seal of the first cylinder and the second cylinder; applying a negative pressure from the negative pressure source to open a first bypass flow path connected to the air flow path and the first cylinder with the first seal, and close a second bypass flow path connected to the fluid flow path and the second cylinder and the catheter connection flow path with the second seal, thereby sucking air from the balloon; applying a positive pressure from the pressurizing / depressurizing device to open the second bypass flow path and the catheter connection flow path with the second seal and close the first bypass flow path with the first seal, thereby supplying fluid to the balloon; A flow path switching method including the steps of: [Effects of the Invention]

[0017] According to the present disclosure, it is possible to provide a highly maneuverable device that can automatically replace the air in the balloon of a catheter with a fluid. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a system according to an embodiment of the present disclosure. [Figure 2] 1 is a flowchart illustrating an operation of a system according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a diagram illustrating a state corresponding to S1 in FIG. 2 of the system according to the embodiment of the present disclosure. [Figure 4] FIG. 3 is a diagram illustrating a state corresponding to S2 in FIG. 2 of the system according to the embodiment of the present disclosure. [Figure 5] FIG. 3 is a diagram illustrating a state corresponding to S3 in FIG. 2 of the system according to the embodiment of the present disclosure. [Figure 6] FIG. 3 is a diagram illustrating a state corresponding to S4 in FIG. 2 of the system according to the embodiment of the present disclosure. [Figure 7] FIG. 3 is a diagram illustrating a state corresponding to S5 in FIG. 2 of the system according to the embodiment of the present disclosure. [Figure 8] FIG. 3 is a diagram illustrating a state corresponding to S6 in FIG. 2 of the system according to the embodiment of the present disclosure. [Figure 9] FIG. 3 is a diagram illustrating a state corresponding to S7 in FIG. 2 of the system according to the embodiment of the present disclosure. [Figure 10] FIG. 3 is a diagram illustrating a state corresponding to S8 in FIG. 2 of the system according to the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0020] In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0021] The configuration of a system 10 according to this embodiment will be described with reference to FIG.

[0022] The system 10 according to this embodiment includes a flow path switch 12 that switches the flow path between the air sucked from a balloon 11 attached to the catheter and the fluid supplied to the balloon 11, a negative pressure source 13 that can apply negative pressure, and a pressure-pressurizing device 14 that can apply negative and positive pressures.

[0023] The fluid is a contrast medium in this embodiment, but may be any type of fluid other than air, such as saline.

[0024] The flow path switch 12 comprises a first cylinder 21, a first seal 31, an air flow path 41, a first bypass flow path 51, a second cylinder 22, a second seal 32, a fluid flow path 42, a second bypass flow path 52, and a catheter connection flow path 43.

[0025] The first seal 31 is a seal that slides within the first cylinder 21. The air flow path 41 is connected to one side of the first seal 31 of the first cylinder 21. The first bypass flow path 51 is connected to the air flow path 41 and is also connected to the first cylinder 21 and is opened and closed by the first seal 31. The second seal 32 is a seal that slides within the second cylinder 22 in conjunction with the first seal 31. The fluid flow path 42 is connected to one side of the second seal 32 of the second cylinder 22. The second bypass flow path 52 is connected to the fluid flow path 42 and is also connected to the second cylinder 22 and is opened and closed by the second seal 32. The catheter connection flow path 43 is connected to the other side of the first seal 31 of the first cylinder 21 and is also connected to the second cylinder 22 and is opened and closed by the second seal 32. The first cylinder 21, the air flow path 41, the first bypass flow path 51, the second cylinder 22, the fluid flow path 42, the second bypass flow path 52, and the catheter connection flow path 43 are formed, for example, by bonding together two resin members having semicircular cross sections, but may also be formed by joining two or more resin members together, or may be formed completely as a single unit. The first seal 31 and the second seal 32 are formed, for example, from an elastic material such as rubber.

[0026] In this embodiment, the flow path switch 12 further includes a third seal 33 and a fourth seal .

[0027] The third seal 33 slides within the second cylinder 22 in conjunction with the second seal 32. The fourth seal 34 slides within the second cylinder 22, separated from the second seal 32 by the third seal 33. The fluid flow path 42 is connected to the second cylinder 22 on the side of the fourth seal 34 opposite the third seal 33. The second bypass flow path 52 and the catheter connection flow path 43 are connected to the second cylinder 22 on the side of the third seal 33 opposite the fourth seal 34. The third seal 33 and the fourth seal 34 are formed of an elastic material such as rubber.

[0028] In this embodiment, the flow path changer 12 further includes a fifth seal 35 .

[0029] The fifth seal 35 slides in the first cylinder 21 in conjunction with the first seal 31. The fifth seal 35 is formed of an elastic body such as rubber.

[0030] In this embodiment, the flow path switcher 12 further includes a first connecting member 61, a second connecting member 62, a third connecting member 63, and a rod 64.

[0031] The combination of the first connecting member 61 and the second connecting member 62 is a connecting member that connects the first seal 31 and the second seal 32 through one open end of the first cylinder 21 and one open end of the second cylinder 22. Specifically, the first connecting member 61 connects the fifth seal 35 and the second seal 32 through one open end of the first cylinder 21 and one open end of the second cylinder 22. The second connecting member 62 connects the first seal 31 and the fifth seal 35. The third connecting member 63 is a connecting member that connects the second seal 32 and the third seal 33. The first connecting member 61, the second connecting member 62, and the third connecting member 63 mechanically connect the first seal 31, the fifth seal 35, the second seal 32, and the third seal 33, synchronizing the movement of these four seals. On the other hand, although the rod 64 is disposed between the third seal 33 and the fourth seal 34, it is fixed only to the fourth seal 34 and not to any connecting member, and synchronizes the movement of the third seal 33 and the fourth seal 34 in only one direction. The first connecting member 61, the second connecting member 62, the third connecting member 63, and the rod 64 are formed of, for example, metal or resin. The rod 64 is not necessarily provided, and a configuration in which the third seal 33 and the fourth seal 34 directly abut each other may be adopted.

[0032] In this embodiment, the first cylinder 21 and the second cylinder 22 are arranged so that their open ends face the same direction. Therefore, the first connecting member 61 extends straight along the axial direction of the first cylinder 21 from the side of the fifth seal 35 opposite the side connected to the first seal 31, bends like a U-turn after exiting the open end of the first cylinder 21, enters the open end of the second cylinder 22, and then extends straight along the axial direction of the second cylinder 22 to the side of the second seal 32 opposite the side connected to the third seal 33. That is, the first connecting member 61 is bent in a substantially U-shape. The second connecting member 62 extends straight along the axial direction of the first cylinder 21. The third connecting member 63 and the rod 64 extend straight along the axial direction of the second cylinder 22.

[0033] In this embodiment, the second cylinder 22 has a stopper 36 that limits the range of movement of the second seal 32. The stopper 36 is formed, for example, as a protrusion on the inner wall of the second cylinder 22. In this embodiment, the stopper 36 is provided at a position that abuts the second seal 32. However, the stopper 36 may be provided at a position that abuts the third seal 33 because the third connecting member 63 synchronizes the movements of the second seal 32 and the third seal 33. Alternatively, instead of providing the stopper 36 on the second cylinder 22, a stopper may be provided on the first cylinder 21. This stopper can limit the range of movement of the second seal 32 by limiting the range of movement of the fifth seal 35 because the first connecting member 61 synchronizes the movements of the fifth seal 35 and the second seal 32. The stopper provided on the first cylinder 21 is provided, for example, at a position that contacts the fifth seal 35, but the second connecting material 62 may also be provided at a position that contacts the first seal 31 in order to synchronize the movement of the first seal 31 and the fifth seal 35.

[0034] The negative pressure source 13 is connected to the air flow path 41 via a negative pressure valve 15. The negative pressure valve 15 is, for example, an electric three-way valve.

[0035] The pressure increasing / depressurizing device 14 is connected to the fluid flow path 42 via a pressure increasing / depressurizing valve 16. The pressure increasing / depressurizing valve 16 is, for example, an electrically operated valve.

[0036] In this embodiment, the first seal 31 and the second seal 32 move due to the negative pressure from the negative pressure source 13 or the positive or negative pressure from the pressure applying device 14, and this movement is synchronized, so that exclusive switching can be performed to prevent the negative pressure from entering the pressure applying device 14 and the contrast agent from entering the negative pressure source 13.

[0037] The operation of the system 10 according to this embodiment will be described with reference to Fig. 2. The operation shown in Fig. 2 corresponds to the flow path switching method according to this embodiment.

[0038] The initial state of the system 10 according to this embodiment is as shown in Fig. 1. A catheter having a balloon 11 attached thereto is connected to the catheter connection flow path 43.

[0039] S1 is a step of applying negative pressure from the negative pressure source 13. The state of the system 10 according to this embodiment corresponding to S1 is shown in FIG.

[0040] In S1, the negative pressure valve 15 is opened. The negative pressure valve 15 may be opened manually, but is preferably opened automatically in response to a switch operation by a user such as a doctor. When negative pressure is applied from the negative pressure source 13, the first seal 31 moves to the right in FIG. 3 until it reaches the end opposite the open end of the first cylinder 21. Because the second connecting member 62 synchronizes the movement of the first seal 31 and the fifth seal 35, the fifth seal 35 also moves to the right in FIG. 3. Because the first connecting member 61 synchronizes the movement of the fifth seal 35 and the second seal 32, the second seal 32 also moves to the right in FIG. 3. Because the third connecting member 63 synchronizes the movement of the second seal 32 and the third seal 33, the third seal 33 also moves to the right in FIG. 3. Because the rod 64 hits the third seal 33 and pushes it together with the fourth seal 34, the fourth seal 34 also moves to the right in FIG. 3.

[0041] S2 is a step in which air is aspirated from the balloon 11 by opening the first bypass flow path 51 with the first seal 31 and closing the second bypass flow path 52 and the catheter connection flow path 43 with the second seal 32. The state of the system 10 according to this embodiment corresponding to S2 is shown in FIG.

[0042] In S2, when the first seal 31 moves to the first open position which opens the first bypass flow path 51, the second seal 32 moves in conjunction with the first seal 31 to the second closed position which closes the second bypass flow path 52 and the catheter connection flow path 43. When the second seal 32 moves in conjunction with the first seal 31 to the second closed position, the third seal 33 moves in conjunction with the second seal 32, and the fourth seal 34 is pushed and moved by the third seal 33. That is, in S2, the movement of the seals closes the positive pressure side and opens the negative pressure side, creating a negative pressure inside the device.

[0043] S3 is a step of applying positive pressure from the pressurizing / depressurizing device 14. The state of the system 10 according to this embodiment corresponding to S3 is shown in FIG.

[0044] In step S3, the pressure regulator valve 16 is opened. The pressure regulator valve 16 may be opened manually, but is preferably opened automatically when a predetermined time has elapsed since step S2. The "predetermined time" is set to a short time, such as 5 seconds. When the pressure regulator 14 applies a positive pressure whose absolute value exceeds the absolute value of the negative pressure applied by the negative pressure source 13, the fourth seal 34 moves leftward in FIG. 5. The rod 64 contacts and pushes the third seal 33, causing the third seal 33 to also move leftward in FIG. 5. The third connecting member 63 synchronizes the movement of the second seal 32 and the third seal 33, causing the second seal 32 to also move leftward in FIG. 5 until it reaches the stopper 36. The first connecting member 61 synchronizes the movement of the fifth seal 35 and the second seal 32, causing the fifth seal 35 to also move leftward in FIG. 5. Since the second connecting member 62 synchronizes the movements of the first seal 31 and the fifth seal 35, the first seal 31 also moves to the left in FIG.

[0045] S4 is a step in which the second bypass flow path 52 and the catheter connection flow path 43 are opened by the second seal 32, and the first bypass flow path 51 is closed by the first seal 31, thereby supplying fluid to the balloon 11. The state of the system 10 according to this embodiment corresponding to S4 is shown in FIG.

[0046] In S4, when the third seal 33 is pushed and moved by the fourth seal 34, the second seal 32 moves together with the third seal 33 to the second open position, which opens the second bypass flow path 52 and the catheter connecting flow path 43. The range of movement of the second seal 32 from the second closed position toward the second open position is limited by the stopper 36. When the second seal 32 moves to the second open position, the first seal 31 moves together with the second seal 32 to the first closed position, which closes the first bypass flow path 51. That is, in S4, the movement of the seals opens the positive pressure side and closes the negative pressure side, and the inside of the device is filled with contrast medium.

[0047] S5 is a step of opening the negative pressure side to the atmosphere. The state corresponding to S5 of the system 10 according to this embodiment is shown in FIG.

[0048] In S5, the negative pressure valve 15 is opened to the atmosphere. Although step S5 is not essential, it is desirable to perform this step because if negative pressure continues to be applied, the first seal 31 may move.

[0049] S6 is a step of expanding the balloon 11. The state of the system 10 according to this embodiment corresponding to S6 is shown in FIG.

[0050] In S6, when a positive pressure is further applied from the pressurizing / depressurizing device 14, the balloon 11 expands.

[0051] S7 is a step of applying negative pressure from the pressurizing / decompressing device 14. The state of the system 10 according to this embodiment corresponding to S7 is shown in FIG.

[0052] In S7, when negative pressure is applied from the pressurizing / depressurizing device 14, the fourth seal 34 moves independently to the right in Figure 9. The rod 64 simply moves away from the third seal 33 and does not affect the movement of the third seal 33. Therefore, the third seal 33 does not move, and the second seal 32, fifth seal 35, and first seal 31 do not move either.

[0053] S8 is a step of deflating the balloon 11. The state of the system 10 according to this embodiment corresponding to S8 is shown in FIG.

[0054] In S8, when the fourth seal 34 moves independently away from the third seal 33, the third seal 33 does not move and the second seal 32 remains in the second open position, so that negative pressure continues to be applied to the balloon 11, causing the balloon 11 to shrink.

[0055] S9 is a step of stopping the pressure application from the pressurizing / depressurizing device 14. After S9, the flow shown in FIG. 2 ends.

[0056] As described above, in this embodiment, the first seal 31 is actuated by negative pressure from the negative pressure source 13. The fifth seal 35 maintains the negative pressure within the device. The fourth seal 34 is actuated by pressure from the pressurizer / depressurizer 14. The second seal 32 and the third seal 33 maintain the pressure within the device. Connecting members, including the first connecting member 61, the second connecting member 62, and the third connecting member 63, synchronize the movements of the first seal 31, the fifth seal 35, the third seal 33, and the second seal 32. The stopper 36 limits these movements. The first bypass flow path 51 and the second bypass flow path 52 operate exclusively in combination with the seal group so that when negative pressure is applied from the negative pressure source 13, the flow path to the balloon 11 opens and the flow path to the pressure regulator 14 closes; when positive pressure is applied from the pressure regulator 14, the flow path to the balloon 11 opens and the flow path to the negative pressure source 13 closes; and even if negative pressure is subsequently applied from the pressure regulator 14, the flow path to the balloon 11 does not close. Therefore, according to this embodiment, switching between applying negative pressure to the device and injecting contrast medium can be performed using only passive elements, without using a valve driven by an actuator, such as a solenoid valve. As a result, the number of components and the cost can be reduced. It is also possible to provide a device that is advantageous for use in sterile fields.

[0057] In this embodiment, the first bypass flow path 51 bypasses the other side of the first seal 31 of the first cylinder 21. A connecting member including a first connecting member 61 and a second connecting member 62 connects the first seal 31 and the second seal 32, and when the first seal 31 moves to the end opposite to the open end of the first cylinder 21, the second seal 32 blocks the interior of the second cylinder 22 from the catheter connecting flow path 43. Therefore, according to this embodiment, when negative pressure is applied to one side of the first seal 31, the second seal 32, which moves in conjunction with the movement of the first seal 31, blocks the interior of the second cylinder 22 from the catheter connecting flow path 43, and negative pressure can be applied to the catheter connecting flow path 43 via the first bypass flow path 51. This makes it possible to deflate the balloon 11 without manually switching the flow path valve.

[0058] In this embodiment, the second cylinder 22 has a stopper 36, and when the second seal 32 comes into contact with the stopper 36, the first seal 31 blocks the first bypass flow path 51. Therefore, according to this embodiment, when positive pressure is applied to one side of the second seal 32, the first seal 31, which moves in conjunction with the movement of the second seal 32, can block the first bypass flow path 51. Therefore, the balloon 11 can be expanded after the air inside the balloon 11 is deflated, without the need for a manual operation to switch the flow path valve.

[0059] In this embodiment, the second seal 32 and the third seal 33 are connected to one side of the fourth seal 34 but are not connected to the fourth seal 34, and the second bypass flow path 52 bypasses the other side of the fourth seal 34 on the second cylinder 22. Therefore, according to this embodiment, when negative pressure is applied to one side of the fourth seal 34, only the fourth seal 34 moves, so the positions of the first seal 31, the second seal 32, and the third seal 33 are not affected, and the balloon 11 can be deflated via the second bypass flow path 52.

[0060] The present disclosure is not limited to the above-described embodiments. For example, two or more blocks shown in the block diagrams may be integrated, or one block may be divided. Two or more steps shown in the flowcharts may be executed in parallel or in a different order, instead of being executed in chronological order as described, depending on the capabilities of the device executing each step, or as needed. Other modifications are possible within the scope of the present disclosure. [Explanation of symbols]

[0061] 10 Systems 11 Balloon 12 Flow path switch 13 Negative pressure source 14 Pressure increase / decrease device 15 Negative pressure valve 16 Pressure regulator valve 21 No. 1 cylinder 22 No. 2 cylinder 31 First Seal 32 Second Seal 33 Third Seal 34 Fourth Seal 35 5th Seal 36 Stopper 41 Air flow path 42 fluid flow path 43 Catheter connection channel 51 First bypass flow path 52 Second bypass flow path 61 1st connection material 62 Second connection material 63 Third connection material 64 Rod

Claims

1. A flow path switcher that switches a flow path between air suctioned from a balloon attached to a catheter and a fluid supplied to the balloon, A first cylinder; a first seal that slides within the first cylinder; an air flow path connected to one side of the first seal of the first cylinder; a first bypass flow path connected to the air flow path and connected to the first cylinder, the first bypass flow path being opened and closed by the first seal; A second cylinder; a second seal that slides within the second cylinder in conjunction with the first seal; a fluid flow path connected to one side of the second seal of the second cylinder; a second bypass flow path connected to the fluid flow path and connected to the second cylinder and opened and closed by the second seal; a catheter connection flow path connected to the first cylinder on the other side of the first seal, and connected to the second cylinder and opened and closed by the second seal; A flow path switcher comprising:

2. 2. The flow path switch according to claim 1, further comprising a connecting member that connects the first seal and the second seal through an open end of the first cylinder and an open end of the second cylinder.

3. When the first seal moves to a first open position to open the first bypass flow path, the second seal moves to a second closed position in conjunction with the first seal to close the second bypass flow path and the catheter connection flow path, 2. The flow path switch of claim 1, wherein when the second seal moves to a second open position that opens the second bypass flow path and the catheter connection flow path, the first seal moves in conjunction with the second seal to a first closed position that closes the first bypass flow path.

4. 4. The flow path changeover device according to claim 3, wherein the second cylinder has a stopper that limits a range of movement of the second seal in a direction from the second closed position toward the second open position.

5. a third seal that slides within the second cylinder in conjunction with the second seal; a fourth seal that is separated from the second seal by the third seal and slides within the second cylinder; and Further provided with the fluid flow path is connected to the second cylinder on the opposite side of the fourth seal from the third seal; The flow path switch according to claim 1 , wherein the second bypass flow path and the catheter connection flow path are connected to the second cylinder on the side opposite the third seal from the fourth seal.

6. When the second seal moves to a second closed position interlocking with the first seal to close the second bypass flow path and the catheter connection flow path, the third seal moves interlocking with the second seal, and the fourth seal is pushed and moved by the third seal; When the third seal is pushed and moved by the fourth seal, the second seal moves in conjunction with the third seal to a second open position that opens the second bypass flow path and the catheter connection flow path, 6. The flow path diverter of claim 5, wherein when the fourth seal moves independently away from the third seal, the third seal does not move and the second seal remains in the second open position.

7. A flow path switcher according to any one of claims 1 to 6; a negative pressure source connected to the air flow path; a pressure increasing / decompressing device connected to the fluid flow path; A system comprising:

8. connecting a negative pressure source to an air flow path connected to one side of a first seal of a first cylinder that slides within the first cylinder; a pressure increasing / depressurizing device connected to a fluid flow path connected to one side of a second seal of a second cylinder, the second seal sliding within the second cylinder in conjunction with the first seal; connecting a catheter having a balloon attached thereto to a catheter connection channel connected to the other side of the first seal of the first cylinder and the second cylinder; applying a negative pressure from the negative pressure source to open a first bypass flow path connected to the air flow path and the first cylinder with the first seal, and closing a second bypass flow path connected to the fluid flow path and the second cylinder and the catheter connection flow path with the second seal, thereby sucking air from the balloon; applying a positive pressure from the pressurizing / depressurizing device to open the second bypass flow path and the catheter connection flow path by the second seal and close the first bypass flow path by the first seal, thereby supplying fluid to the balloon; A flow path switching method including the steps of:

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