JP2007069019A - Three-way stopcock - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-way stopcock that can be opened/closed easily while reducing stagnated portions of a fluid in a fluid flow passage. <P>SOLUTION: The three-way stopcock is equipped with a substantially cylindrically shaped body part 11 having a first through a third branch openings on its outer periphery and a flow passage switching portion 15 that is mounted rotatably in the cavity of the body part. The flow passage switching portion has a first flow passage opening 181 forming a first flow passage from the first branch opening 121 to the third branch opening 123, and a second flow passage opening 182 forming a second flow passage from the third branch opening to the second branch opening 122, the passage which is separated from the first flow passage opening. On the outer peripheral side of the flow passage switching portion, only openings are formed with the end of each flow passage opening. Openings formed with one end of each flow passage opening are arranged separably with certain distance among them, and openings formed with the other end of each flow passage opening are arranged adjacently. When the body part and flow passage switching portion are configured at a specified moving location, each of the first and second flow passage openings simultaneously forms the first and second flow passage, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  According to the present invention, a fluid flow path is formed by connecting predetermined branch openings among the three branch openings by rotating a flow path switching section provided in a main body having three branch openings. This is related to a three-way stopcock that can switch between routes.

  When transfusion or blood transfusion therapy is performed in a medical institution, a three-way stopcock is used to mix different drug solutions or collect fluid flowing through a fluid flow path. FIG. 9 shows an overall perspective view of a conventional three-way stopcock. The conventional three-way stopcock has a main body section 1 and a flow path switching section provided with a branch pipe through which a fluid connected to three branch openings can flow. The combination of the branch pipe from which the chemical liquid that flows into communication with the branch pipe into which the chemical liquid flows in can be selected by rotating the handle 7 that is configured integrally with the flow path switching unit 5. It is configured as follows.

  Of the three branch pipes in the conventional three-way cock, the first branch pipe 31 and the second branch pipe 32 are arranged so as to form a linear flow path when they are communicated with each other. Line. Further, the branch pipe arranged so as to be positioned perpendicular to the main line is used as the third branch pipe 33, and a chemical solution is mixed and collected from the third branch pipe 33.

  On the other hand, FIG. 10 shows a cross-sectional view of a conventional three-way cock. As shown in FIG. 10, the main body 1 has three branch openings 21 so that the first branch pipe 31, the second branch pipe 32, and the third branch pipe 33 can be selectively combined. , 22 and 23 are provided.

  FIG. 11 is a schematic diagram showing the direction of the flow path in the flow path switching section of the conventional three-way cock. As shown in FIG. 11, the flow path switching unit 5 is provided with three flow path ports 61, 62 and 63. Further, the fluid flow path 8 provided in the flow path switching unit 5 branches vertically from the flow path that linearly communicates with the first flow path port 61 and the second flow path port 62 from the center of the flow path. It is configured in such a manner that it is configured by a flow path communicating with the third flow path port 63, that is, configured in a T shape.

  However, the third branch pipe 33 may become an open system with respect to the outside at the time of co-infusion, and there is a possibility that bacteria may be mixed. That is, since the third branch pipe 33 has a hollow and long tubular structure and it is difficult to disinfect the long pipe lumen, the lumen in the third branch pipe 33 is a warm bed of bacteria. There was a risk of becoming.

  Further, as shown in FIG. 10, since the flow path switching unit 5 is configured in a T-shape branched in the middle, the portion X of the flow path communicating with the third flow path port 63 has a main line. The flow did not reach and there was a risk of becoming a staying part. Due to the presence of the staying part, there is a problem that a drug solution to be administered remains, and accurate drug administration becomes difficult.

  On the other hand, in recent medical sites, a dedicated blunt needle is often used instead of a sharp metal needle as an insertion member of a mixed injection tool such as a syringe used for mixed injection.

For this reason, the partition comprised with the elastic body which has the slit which can be punctured by the blunt needle as disclosed in Patent Document 1 is provided at a position corresponding to the third branch pipe, and the third branch pipe 33 Many three-way stopcocks have been developed to eliminate the stagnant part. The three-way stopcock disclosed in Patent Document 1 is a medical stopcock characterized by forming an arc-shaped groove-like switching path along the circumferential surface at the switching portion of the flow path. By separating a partition made of an elastic body having a slit at a corresponding position, it is isolated from the outside, ensuring a closed system, and at the same time, the flow path length is made shorter than before. Furthermore, by forming an arc-shaped groove-shaped switching path along the circumferential surface in the switching portion of the flow path, a fluid flow is also generated in a portion that has been a conventional retaining portion, thereby eliminating the retaining portion. .
JP 11-342209 A

  However, with these three-way stopcocks, in the method of closing all the flow paths, the method of closing the flow paths by slightly shifting the phase of the fluid flow path, which was a general method with the conventional three-way stopcocks, cannot be adopted. was there. That is, the intermediate point of the angle formed between the position corresponding to the third branch pipe 33 and the first branch pipe 31 or the second branch pipe 32 from the state shown in FIG. It is a problem that the entire flow path cannot be closed by rotating it (45 degrees or 315 degrees).

  For example, in the three-way cock disclosed in Patent Document 1, it is necessary to rotate the fluid switching unit 5 from about 135 degrees to 225 degrees when closing all the flow paths. This is because in the conventional three-way stopcock, the flow path switching portion 5 has three openings, whereas the flow path switching portion 5 has an arcuate groove shape along the circumferential surface. This is due to the opening. In an actual medical field, since it is necessary to perform particularly complicated operations in a short time, the three-way stopcock having such a configuration has a possibility of causing an erroneous operation during use.

  In view of the above circumstances, an object of the present invention is to provide a three-way stopcock that can perform the same opening / closing operation as a conventional operation method while reducing a fluid retention portion in a fluid flow path.

  The three-way stopcock of the present invention is mounted so as to be rotatable and liquid-tight with respect to a cylindrical lumen of the main body portion, which has a substantially cylindrical shape having first to third branch openings on the outer periphery. A flow path switching section having a flow path hole that forms a fluid flow path so that the predetermined branch opening sections can communicate with each other among the branch opening sections, and the flow path switching section includes the main body. The fluid flow path is switched by rotating the part.

  In order to solve the above-described problem, the flow path hole includes a first flow path hole for forming a first fluid flow path from the first branch opening to the third branch opening; The first flow path hole is a path separated from the main path, and a second flow path hole for forming a second fluid flow path from the third branch opening to the second branch opening. The opening location formed on the outer peripheral surface of the flow path switching unit is only each opening formed by the end portions of the first flow path hole and the second flow path hole, The two openings formed by one end of each of the first and second flow path holes are disposed adjacent to each other, and the relative rotational positions of the main body and the flow path switching section are set. When set to a predetermined state, the first and second flow path holes simultaneously form the first and second fluid flow paths, respectively. It is placed in so that.

  According to the three-way cock having the above-described configuration, the three flow path openings that are opened in the flow path switching unit are provided, and the two fluid paths that connect the flow path ports are formed so as to communicate with each other. Thus, the fluid flow also reaches this space, and the stagnation of the fluid can be eliminated by performing priming or the like.

  Furthermore, there are only three flow path openings in the flow path switching unit, and by aligning the portion of the flow path switching unit where the three flow path ports do not exist with the position of each branch opening in the main body, Can be prevented from communicating with each branch opening in the main body, so that the same operation method as that in the conventional three-way cock can be realized.

  In the three-way cock according to the present invention, the two openings formed by the other ends of the first and second flow path holes are spaced apart from each other, and the relative relationship between the main body part and the flow path switching part is When the specific rotation position is set to a predetermined state, the two opening portions formed by the one end portions of the first and second flow path holes become the third branch opening portions. The two openings formed by the other ends of the first and second flow path holes are opposed to the first branch opening and the second branch opening, respectively. The first and second flow path holes are preferably arranged so as to simultaneously form the first and second fluid flow paths, respectively.

  The two openings formed by the other ends of the first and second flow path holes are spaced apart from each other and are disposed at positions facing each other in the radial direction of the flow path switching section. Preferably it is.

  In that case, the two openings formed by the one end of the first and second flow path holes are the two openings formed by the other end of the flow path holes. It is preferable that it is arrange | positioned in the intermediate position of a part.

  Further, the two opening portions formed by the one end portions of the first and second flow path holes may be aligned in the axial direction of the main body portion. Thereby, the range in which the phase is shifted so as to match the portion where the three channel openings of the channel switching unit do not exist with the position of each branch opening in the main body can be reduced.

  Alternatively, the two openings formed by the one end portions of the first and second flow path holes may be aligned in a direction intersecting the axial direction of the main body portion. .

  Moreover, it is preferable that the mixed injection port is provided in the side wall part which forms the said 3rd branch opening part.

  The ratio of the cross-sectional area of the third branch opening to the cross-sectional area of the fluid flow path is preferably (1: 12.25) or more. When it is 1: 12.25 or more, it has been experimentally confirmed that no stagnation occurs due to priming.

  By configuring an infusion circuit or a blood transfusion circuit using the three-way cock as described above, the same effect can be expected for the infusion circuit or the blood transfusion circuit.

  The “up and down direction” used in the three-way cock described in this specification means a position in a three-way cock state in which the handle provided in the flow path switching unit is the uppermost part and the other end is the lowermost part. The relationship, that is, the rotation axis direction of the flow path switching unit is defined as “vertical direction”. The “horizontal direction” is defined as a positional relationship in a direction perpendicular to the “up and down direction”.

  Hereinafter, details of the three-way cock according to the embodiment of the present invention will be described with reference to the accompanying drawings.

  First, FIG. 1 shows a perspective view of a three-way cock according to an embodiment of the present invention. The three-way stopcock according to the embodiment of the present invention has a substantially cylindrical main body 11 having three branch openings on its periphery, and is rotatable with respect to the main body 11 and mounted so as to be liquid-tight. And each of the branch openings in the main body 11 has three channel openings for forming a fluid channel so that predetermined branch openings can communicate with each other, and is configured integrally with the handle 17. It is comprised from the flow-path switching part which has.

  FIG. 2 is a cross-sectional view of the three-way cock according to the embodiment of the present invention. As shown in FIG. 2, three branch openings 121, 122, and 123 are formed in the main body 11. The first branch opening 121 and the second branch opening 122 are formed so as to face each other on the outer periphery of the main body 11, and the third branch opening 123 is on the outer periphery of the main body 11. In addition, the first branch opening 121 and the second branch opening 122 are formed at positions that are equally spaced by 90 degrees. In addition, a first branch pipe 131 and a second branch pipe 132 are connected to the first branch opening 121 and the second branch opening 122, respectively, so as to introduce or lead out fluid.

  On the other hand, the mixed injection port 14 is connected to the third branch opening 123. The mixed injection port 14 includes a diaphragm 141 through which a needle or the like can be punctured, and is provided so that the fluid flow path 18 in the three-way stopcock is blocked from the outside. A cover 142 fixes the diaphragm 141 and only the insertion portion is provided. It is the structure which exposes. This makes it possible to ensure that a closed system with the outside in the fluid flow path 18 in the three-way stopcock is formed.

  In addition, the mixed injection port 14 used for the three-way cock according to the present invention may be any known mixed injection port. The diaphragm 141 can be punctured with a needle or the like, and after the needle is removed, the fluid channel closed system may be maintained. In addition, the diaphragm 141 may be provided with a slit in advance so that a needle can be easily punctured and liquid tightness can be secured. Furthermore, the structure which can insert blunt inserts, such as a lure, and can ensure liquid-tightness may be sufficient.

  The flow path switching unit 15 is rotatable in the main body 11 and is mounted so as to be liquid-tight. FIG. 3 is a schematic diagram showing the directionality of the flow path in the flow path switching unit 15 of the three-way cock according to the embodiment of the present invention. In FIG. 3, the arrows indicate the direction of fluid flow.

  The flow path switching unit 15 has three flow path ports 161, 162, and 163. The first channel port 161 and the second channel port 162 are formed at opposing positions on the outer periphery of the channel switching unit 15, and the third channel port 163 is on the outer periphery of the channel switching unit 15. The flow path ports 161 and the second flow path ports 162 are formed at positions that are equally spaced by 90 degrees.

  The fluid channel 18 provided in the channel switching unit 15 includes a first fluid channel 181 that connects the first channel port 161 and the third channel port 163, and a second channel port 162. The second fluid channel 182 communicates with the third channel port 163. Further, the first fluid channel 181 and the second fluid channel 182 are provided so as to communicate with each other in the vicinity of the third channel port 163.

  Various means are conceivable as means for allowing the first fluid channel 181 and the second fluid channel 182 to communicate in the vicinity of the third channel port 163. For example, as shown in FIG. 3, a groove portion 193 (between the proximal end portion 191 of the first fluid passage 181 and the proximal end portion 192 of the second fluid passage 182 inside the third passage opening 163. Providing the hatched portion in FIG. 3 is also considered effective.

  Further, the base end portions 191 and 192 of the third fluid port 163 of the first fluid channel 181 and the second fluid channel 182 are in the vertical direction of the main body portion 11 of the three-way cock, and the first channel port 161. The second fluid flow connecting the second channel port 162 and the third channel port 163 is located on the lower side of the base end 191 of the first fluid channel 181 that communicates with the third channel port 163. The base end 192 of the path 182 is provided so as to be positioned on the upper side.

  FIG. 4 is a longitudinal sectional view in a state in which the flow path switching unit 15 is rotated so that the third flow path port 163 is located at the same position as the third branch opening 123 provided with the mixed injection port 14 having the diaphragm 141. Shown in

  As shown in FIG. 4, the fluid introduced from the first fluid flow path 181 changes direction by passing through the space in the groove 193 and the third branch opening 123 at the third branch opening 123. Then, it flows to the second fluid flow path 182 located on the upper side. At that time, since the fluid circulates through the space formed in the third branch opening 123 in the main body 11, the space does not become a fluid retention portion.

  At this time, in order to circulate the fluid to the space in the third branch opening 123, the larger the cross-sectional area of the first fluid channel 181 and the second fluid channel 182, the more efficiently the reflux flow. To do. However, since the first fluid channel 181 and the second fluid channel 182 exist in the third branch opening 123, the cross-sectional areas of the first fluid channel 181 and the second fluid channel 182 are present. A is not smaller than 1: 2 with respect to the cross-sectional area B in the third branch opening 123.

  On the other hand, when the cross-sectional area A of the first fluid channel 181 and the second fluid channel 182 is reduced, it is difficult to secure a flow rate as a three-way cock, and a fluid with a high viscosity functions as a fluid channel. It becomes difficult.

  Therefore, the first fluid channel 181 and the second fluid channel 182 are formed in the third branch opening 123 with the configuration shown in FIG. In this experiment, it is determined whether the space formed in the third branch opening 123 is a fluid retention portion by measuring the residual impurity concentration after priming. went.

  As a result, in the configuration shown in FIG. 5, no impurities remain, and at least the cross-sectional area A of the first fluid channel 181 and the second fluid channel 182 is the third branch opening 123. If the area ratio is 1: 12.25 or more with respect to the cross-sectional area B, the fluid can be circulated to the space in the third branch opening 123, and a fluid retention portion is generated. There is nothing.

  On the other hand, it is difficult to make the diameters of the first fluid channel 181 and the second fluid channel 182 smaller than 1 mm from the viewpoint of the manufacturing process. In addition, when the diameters of the first fluid channel 181 and the second fluid channel 182 are smaller than 1 mm, clogging or the like is likely to occur for a liquid having a relatively high fluid viscosity such as blood, The fact that it does not flow smoothly is empirically clear. Therefore, the cross-sectional area A of the first fluid channel 181 and the second fluid channel 182 has an area ratio of 1:49 or more with respect to the cross-sectional area B in the third branch opening 123. It is desirable to be.

  Further, depending on the configuration of the mixed injection port 14, the space itself in the third branch opening 123 may not exist, but even in this case, the fluid introduced from the first fluid flow path 181 The direction is changed by passing through the groove portion 193 in the third branch opening portion 123 and flows to the second fluid channel 182 located on the upper side.

  On the other hand, the first fluid channel 181 and the second fluid channel 182 having the base end portions 191 and 192 at the third channel port 163 respectively maintain the vertical positional relationship of the channel switching unit 15. It extends toward the center, bends at the center, and extends to the first flow path port 161 and the third flow path port 163, respectively.

  Thereby, the fluid flow path in the flow path switching unit 15 communicates and opens from the first flow path opening 161 to the third flow path opening 163 and from the third flow path opening 163 to the second flow path opening 162. There are also only three places, the first flow path port 161, the second flow path port 162, and the third flow path port 163, which are the same as the openings in the flow path switching unit of the conventional three-way cock.

  Therefore, in order to prevent each flow passage port from communicating with each branch opening in the main body portion 11, a portion on the outer periphery of the flow passage switching portion 15 that does not have a flow passage port is provided in each branch opening in the main body portion 11. This is possible by matching the position of the part.

  Note that, in the third channel port 163, the base end portion 191 of the first fluid channel 181 that communicates with the first channel port 161 and the second fluid channel that communicates with the second channel port 162. Since the base end portion 192 of 182 is provided so as to have a vertical positional relationship in the vertical direction of the main body portion 11, the two fluid flow paths communicate with each other in the vertical direction at the third flow path port 163. Will be.

  The position where the base end portion 191 and the base end portion 192 are disposed is not particularly limited to this, and for example, the base end portion 191 and the base end portion 192 may be provided horizontally in the left-right direction of the main body portion 11.

  However, the length of the third channel port 163 on the outer periphery of the channel switching unit 15 (the length in the horizontal direction) is due to the two fluid channels communicating with each other in the vertical direction at the third channel port 163. However, as compared with the case where the two fluid flow paths are communicated in the horizontal direction, it is shorter. Therefore, since the opening part on the outer periphery of the flow path switching unit 15 can be made smaller, it is possible to secure more parts where there are no openings on the outer periphery of the flow path switching part 15, and each flow path port has each part in the main body part 11. When not communicating with the branch opening, it is possible to close all the channels without causing the channel switching unit 15 to rotate significantly with respect to the main body 11. That is, it is possible to close all the branch openings by matching the locations where the three flow path openings in the flow path switching unit 15 do not exist with the positions of the branch openings in the main body 11.

  At this time, in order to switch from the communication state to the non-communication state (closed state), it is necessary to rotate the flow path switching unit 15, and when there are a large number of horizontal openings, more phase shifts are required. Is required. However, if there are few openings in the horizontal direction, it is possible to switch to a non-communication state (closed state) with only a slight phase shift.

  In the present embodiment, the third channel port 163 communicates with the base end 191 of the first fluid channel 181 that communicates with the first channel port 161 and the second channel port 162. As for the positional relationship with the base end 192 of the second fluid channel 182, the base end 191 of the first fluid channel 181 is on the lower side, and the base end 192 of the second fluid channel 182 is on the upper side. However, the same effect can be expected even if the vertical positional relationship between the two is reversed.

  Furthermore, the configuration of the fluid channel in the channel switching unit 15 is not limited to the configuration described above. For example, as shown in FIG. 6, the first fluid channel 181 and the second fluid channel 182 having the base ends 191 and 192 at the third channel port 163 are respectively connected from the third channel port 163. A configuration is also conceivable in which the first channel port 161 and the second channel port 162 are linearly extended.

  Of course, the first fluid channel 181 and the second fluid channel 182 are provided so as to communicate with each other in the vicinity of the third channel port 163, and the first fluid channel 181 and the second fluid channel 182 are provided. As a means for enabling communication between the base end 191 of the first fluid channel 181 and the base end of the second fluid channel 182 in the third channel port 163 as in FIG. It is also conceivable to provide a groove portion 193 (shaded portion in FIG. 6) with respect to 192.

  7 shows a cross-sectional view of the flow path switching unit 15 shown in FIG. 6. The fluid flow path formed inside the flow path switching unit 15 is connected to the first flow path port 161. One fluid channel is formed so as to flow out to the second channel port 162 through the third channel port 163.

  Also in such a configuration, as in the above-described embodiment, the flow path switching unit 15 has only three openings, the first flow path port 161, the second flow path port 162, and the third flow path port 163. It can be set as the opening part in the flow-path switching part of the conventional three-way cock, and the same effect can be expected.

  Alternatively, as shown in FIG. 8, the size of the third opening 163 is the same as that of the first opening 161 and the second opening 162, and the first fluid flow path 181 and the second fluid flow A configuration is also conceivable in which the path 182 linearly extends from the third flow path port 163 to the first flow path port 161 and the second flow path port 162, respectively.

  Of course, the first fluid channel 181 and the second fluid channel 182 are provided so as to communicate with each other in the vicinity of the third channel port 163, and the first fluid channel 181 and the second fluid channel 182 are provided. As a means for enabling communication between the base end 191 of the first fluid channel 181 and the base end of the second fluid channel 182 in the third channel port 163 as in FIG. It is also conceivable to provide a groove 193 (shaded portion in FIG. 8) between the 192 and 192.

  Even with such a configuration, as in the above-described embodiment, the flow path switching unit 15 has only three openings, the first flow path port 161, the second flow path port 162, and the third flow path port 163. It can be set as the opening part in the flow-path switching part of the conventional three-way cock, and the same effect can be expected.

  Further, since the two fluid flow paths communicate with each other at the third flow path port 163, it is not necessary to consider whether the base end portion of the fluid path is positioned in the vertical direction or the horizontal direction. . Accordingly, since the opening portion on the outer periphery of the flow path switching unit 15 can be minimized, in the case where each flow path port does not communicate with each branch opening in the main body 11, the flow path switching unit. It is possible to close the entire flow path without greatly rotating 15 with respect to the main body 11.

  As the material of the three-way cock main body, polycarbonate, polypropylene, polyacetal, acrylic resin, polycarbonate alloy, or the like is usually used.

  As described above, according to the three-way cock according to the present invention, the fluid flow path provided in the flow path switching unit of the three-way cock is provided so as to communicate with the mixed injection port. Since it circulates through the space formed in the branch opening, no staying portion is generated in the space in the main body. This makes it possible to eliminate the fluid retention portion in the three-way cock.

  Further, according to the three-way cock according to the present invention, since each opening can be provided at the same position as the conventional three-way cock, it is possible to perform the same opening and closing operation as the conventional one, and an erroneous operation by a medical worker This can be prevented beforehand.

1 is an overall perspective view of a three-way cock according to an embodiment of the present invention. It is a cross-sectional view of the three-way cock according to the embodiment of the present invention. It is a schematic diagram which shows the directionality of the flow path in the flow-path switching part of the three-way cock concerning embodiment of this invention. It is a longitudinal cross-sectional view in the flow-path switching part of the three-way cock according to the embodiment of the present invention. It is a front view of the 3rd branch opening part in the three-way cock concerning an embodiment of the invention. It is a schematic diagram which shows the directionality of the flow path in the flow-path switching part in another Example of the three-way cock concerning embodiment of this invention. It is a cross-sectional view in another Example of the three-way cock according to the embodiment of the present invention. It is a schematic diagram which shows the directionality of the flow path in the flow-path switching part in another Example of the three-way cock concerning embodiment of this invention. It is a whole perspective view of the conventional three-way cock. It is a cross-sectional view of a conventional three-way cock. It is a schematic diagram which shows the directionality of the flow path in the flow-path switching part of the conventional three-way cock.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body part 5 Flow path switching part 7 Handle 11 Main body part 14 Mixed injection port 15 Flow path switching part 17 Handle 18 Fluid flow path 21, 22, 23 Branch opening part 31 1st branch pipe 32 2nd branch pipe 33 3rd Branch pipes 61, 62, 63 Flow path openings 121, 122, 123 Branch opening 131 First branch pipe 132 Second branch pipe 141 Diaphragm 142 Cover 161, 162, 163 Flow path port 181 First fluid flow path 182 First Two fluid flow paths 191 Base end 192 Base end 193 Groove

Claims (8)

A main body having a substantially cylindrical shape having first to third branch openings on the outer periphery;
A flow that is mounted to be rotatable and liquid-tight with respect to the cylindrical lumen of the main body, and that forms a fluid flow path so that the predetermined branch openings among the branch openings can communicate with each other. A flow path switching unit having a path hole,
In the three-way stopcock in which the fluid channel is switched by rotating the channel switching unit with respect to the main body,
The channel hole includes a first channel hole for forming a first fluid channel from the first branch opening to the third branch opening, and the first channel hole. Includes a second flow path hole for forming a second fluid flow path from the third branch opening to the second branch opening in a path separated in the main path,
The opening locations formed on the outer peripheral surface of the flow path switching unit are only the respective openings formed by the end portions of the first flow path hole and the second flow path hole,
The two openings formed by one end of each of the first and second flow path holes are disposed adjacent to each other;
When the relative rotation position of the main body and the flow path switching unit is set to a predetermined state, the first and second flow path holes respectively pass through the first and second fluid flow paths. A three-way stopcock, which is arranged to be formed at the same time. The two openings formed by the other ends of the first and second flow path holes are spaced apart from each other;
When the relative rotation position of the main body and the flow path switching unit is set to a predetermined state, the two formed by the one end of the first and second flow path holes An opening is opposed to the third branch opening, and the two openings formed by the other ends of the first and second flow path holes are the first branch opening and the first 2. The three-way assembly according to claim 1, wherein the first and second flow path holes are respectively arranged so as to form the first and second fluid flow paths at the same time so as to face each of the two branch openings. Stopcock.   The two openings formed by the other ends of the first and second flow path holes are spaced apart from each other and disposed at positions facing each other in the radial direction of the flow path switching section. Item 3. The three-way stopcock according to item 1.   The two openings formed by the one end of the first and second flow path holes are intermediate positions of the two openings formed by the other end of the flow path holes. The three-way stopcock according to claim 3, which is disposed on the side.   The two said opening parts formed of the said one edge part of the said 1st and 2nd flow-path hole are aligned in the axial direction of the said main-body part. Three-way stopcock.   The two openings formed by the one end of the first and second flow path holes are aligned in a direction intersecting the axial direction of the main body. The three-way stopcock according to item 1.   The three-way cock according to any one of claims 1 to 6, wherein a mixed injection port is provided in a side wall portion that forms the third branch opening.   The three-way cock according to claim 7, wherein a ratio of a cross-sectional area of the third branch opening to a cross-sectional area of the fluid flow path is (1: 12.25) or more.

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