A flow path switching valve and its operating method, and a liquid chromatograph equipped with this flow path switching valve.

Abstract

The present invention provides a flow path switching valve that does not require an additional fluid supply mechanism, efficiently removes wear particles generated on the sliding surface between the stator and rotor, effectively prevents wear particles from accumulating on the sliding surface, and ultimately achieves a longer service life. [Solution] The flow path switching valve 1 of the present invention comprises a stator 11 and a rotor 12 that rotates while sliding in contact with the stator 11, wherein the stator 11 has a plurality of through holes 31, the rotor 12 has flow path grooves 32 that communicate with the through holes 31, and the sliding surface S2 of the rotor 12 has a wear debris discharge groove 33, one end of the wear debris discharge groove 33 is located within the sliding surface S2, and the other end of the wear debris discharge groove 33 faces the outside of the sliding surface S2.

Description

Technical Field

[0001] The present invention relates to a flow path switching valve, an operation method thereof, and a liquid chromatograph including the flow path switching valve.

Background Art

[0002] Conventionally, a flow path switching valve having a stator and a rotor having a sample groove and a cleaning groove formed on a contact surface with respect to the stator is known (see, for example, Patent Document 1). Specifically, this flow path switching valve has a pair of sample grooves that extend in an arc shape in the circumferential direction on the contact surface on the rotor side with respect to the stator, and an arc-shaped cleaning groove that extends in the circumferential direction on the outer peripheral side of these sample grooves and surrounds the pair of sample grooves. Further, a sample flow port is formed in the stator so as to face the sample groove of the rotor, and a cleaning liquid flow port is formed so as to face the cleaning groove of the rotor.

[0003] In this flow path switching valve, when the rotor rotates with respect to the stator at a predetermined angle, the flow path on the stator side of the sample flowing through the sample groove on the rotor side is switched. Further, in this flow path switching valve, the contact surface between the sliding stator and rotor is cleaned by a cleaning liquid such as distilled water that constantly flows through the cleaning groove on the rotor side. According to such a flow path switching valve, even during the analysis of a sample by a predetermined apparatus to which the flow path switching valve is applied, the space between the stator and the rotor is automatically cleaned. As a result, the flow path switching valve can prevent salts and the like contained in the sample from depositing as dry matter between the stator and the rotor without separately performing a cleaning operation after use.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in flow path switching valves, which generally switch the flow path of a sample by the rotation of a rotor, fine wear particles can be generated due to friction between the rotor and the stator. These wear particles further accelerate wear at the contact surface between the rotor and the stator, and gradually accumulate on the contact surface. This wear at the contact surface between the rotor and the stator hinders the adhesion between the rotor and the stator. Furthermore, the accumulated wear particles increase the frictional resistance of the rotor against the stator, hindering the smooth flow path switching operation of the flow path switching valve. Ultimately, the generation of wear particles reduces the service life of the flow path switching valve.

[0006] Therefore, it is conceivable to use a conventional flow path switching valve (see, for example, Patent Document 1) that has a cleaning function between the stator and the rotor, for the purpose of removing wear particles generated on the contact surface (sliding surface) between the rotor and the stator. However, conventional flow path switching valves (see, for example, Patent Document 1) are configured to clean the liquid sample remaining between the stator and rotor, and have the problem of not being able to efficiently remove the solid wear particles that are generated. In addition, conventional flow path switching valves require an additional liquid supply mechanism, such as a liquid supply device for the cleaning fluid, which leads to the problem of the predetermined device using this flow path switching valve becoming large.

[0007] The object of the present invention is to provide a flow path switching valve and a method for operating the same, as well as a liquid chromatograph equipped with this flow path switching valve, which can efficiently remove wear particles generated on the sliding surface between the stator and rotor without requiring an additional liquid supply mechanism, efficiently prevent the accumulation of wear particles on the sliding surface, and ultimately achieve a longer service life. [Means for solving the problem]

[0008] The flow path switching valve of the present invention, which solves the above problems, comprises a stator and a rotor that rotates while sliding in contact with the stator, wherein the stator has a plurality of through holes, the rotor has flow path grooves that communicate with the through holes, and at least one of the sliding surfaces of the rotor and the stator has a wear particle discharge groove, one end of the wear particle discharge groove is located within the sliding surface, and the other end of the wear particle discharge groove faces the outside of the sliding surface. Furthermore, the method for operating the flow path switching valve of the present invention, which solves the problem, is a method for operating the flow path switching valve, comprising: a flow path switching step by the rotor that switches the conductivity between the through hole of the stator and the flow path groove of the rotor; and a wear powder discharge step by the rotor that discharges wear powder from the sliding surface through the wear powder discharge groove. Furthermore, the liquid chromatograph of the present invention, which solves the aforementioned problems, is equipped with the flow path switching valve. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a flow path switching valve and a method for operating the same, as well as a liquid chromatograph equipped with this flow path switching valve, which do not require an additional liquid supply mechanism, efficiently remove wear particles generated on the sliding surface between the stator and rotor, efficiently prevent the accumulation of wear particles on the sliding surface, and consequently achieve a longer service life. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram illustrating the configuration of a flow path switching valve according to an embodiment of the present invention. [Figure 2] This is a partial top view of the rotor constituting a flow path switching valve according to an embodiment of the present invention. [Figure 3] This is a partial bottom view of the stator constituting a flow path switching valve according to an embodiment of the present invention. [Figure 4A] This diagram shows the positional relationship between the stator and the rotor in contact with the stator at a first position in a flow path switching valve according to an embodiment of the present invention. [Figure 4B]It is a diagram showing the positional relationship between a stator and a rotor that is in contact with the stator at a second position in a flow path switching valve according to an embodiment of the present invention. [Figure 5] It is a configuration explanatory diagram of a liquid chromatograph including a flow path switching valve according to an embodiment of the present invention. [Figure 6] It is a configuration explanatory diagram of a first modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 7] It is a configuration explanatory diagram of a second modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 8] It is a configuration explanatory diagram of a third modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 9] It is a configuration explanatory diagram of a fourth modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 10] It is a configuration explanatory diagram of a fifth modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 11] It is a configuration explanatory diagram of a sixth modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 12A] It is a partial top view of a rotor in a seventh modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 12B] It is a partial bottom view of a stator in a seventh modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 13A] It is a partial top view of a rotor in an eighth modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 13B] It is a partial bottom view of a stator in an eighth modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 14] It is a configuration explanatory diagram of a ninth modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 15] It is a configuration explanatory diagram of a tenth modification example of a flow path switching valve according to an embodiment of the present invention. [Figure 16] It is a flowchart showing the procedure executed by a control unit that constitutes the flow path switching valve shown in FIG. 15.

Embodiments for Carrying Out the Invention

[0011] A mode (embodiment) for implementing the flow path switching valve of the present invention and a liquid chromatograph equipped with the same will be described in detail with reference to the drawings as appropriate. Hereinafter, the flow path switching valve applied to the liquid chromatograph will be described. However, the flow path switching valve of the present invention is not limited to this, and can be used in various chemical analyzers other than the liquid chromatograph. In addition, the flow path switching valve of the present invention can also be applied to the flow path switching valve in a liquid-liquid contact device such as a micro reactor.

[0012] (Flow path switching valve) FIG. 1 is a configuration explanatory diagram of the flow path switching valve 1 according to the present embodiment. FIG. 1 is a longitudinal sectional view of the flow path switching valve 1 corresponding to the I-I cross section of FIG. 4A described later. In the following description, the vertical direction is based on the vertical direction indicated by the arrow in FIG. 1. As shown in FIG. 1, the flow path switching valve 1 mainly includes a stator 11 and a rotor 12 that rotates while slidingly contacting the stator 11.

[0013] The stator 11 in the present embodiment is assumed to be made of a metal such as stainless steel or a ceramic. In addition, as the stator 11, one having a diamond-like carbon coated on its surface can also be used. The stator 11 has a stator main body 11a, a rotor contact portion 11b that is provided integrally with the stator main body 11a and contacts the rotor 12, and a flange portion 11c that is provided integrally with the stator main body 11a and is supported by the support portion 14.

[0014] The stator main body 11a is formed so as to occupy most of the stator 11 and has a substantially cylindrical outer shape. The rotor contact portion 11b is formed to have a smaller diameter than the stator body 11a and is formed in a circular, trapezoidal shape that protrudes downward from the lower surface of the stator body 11a. The rotor contact portion 11b has a circular lower surface in a plan view that is perpendicular to the axis of the stator body 11a and is coaxial with the axis of the stator body 11a. This lower surface forms the sliding surface S1 of the stator 11 with respect to the rotor 12 (see Figure 3).

[0015] The flange portion 11c is formed to partially protrude outward from the circumferential surface of the lower end of the stator body 11a. The flange portion 11c is fixed to the support portion 14 with screws (not shown) or the like. As a result, the stator body 11a is supported by the support portion 14 via the flange portion 11c. In this embodiment, the support portion 14 can utilize a part of the housing (not shown) that houses the stator 11 and rotor 12, or it can be constructed from a separate component from the housing.

[0016] The stator 11 has a plurality of through holes 31 through which a liquid sample flows. The through holes 31 are formed to penetrate vertically through the stator body 11a and the rotor contact portion 11b. The liquid flow port 31a formed at the lower end of the through hole 31 will face the flow channel groove 32 of the rotor 12, which will be described later, when the rotor 12 rotates relative to the stator 11 to a predetermined rotation angle. In other words, the through hole 31 will communicate (conduct) with the flow channel groove 32. Furthermore, the piping P (see Figure 5) of an analytical device (for example, the liquid chromatograph 100 (see Figure 5) described later) will be connected to the upper end of the through hole 31. The arrangement of the through-holes 31 will be explained in detail later.

[0017] Next, we will explain the rotor 12 (see Figure 1). As shown in Figure 1, the rotor 12 comprises a rotor body 12a and a rotor seal 12b. In this embodiment, the rotor body 12a is assumed to have a substantially cylindrical outer shape made of a metal such as stainless steel. A disc-shaped rotor seal 12b is attached to the upper surface of the rotor body 12a by pins (not shown) or the like so as to be coaxial with the rotor body 12a.

[0018] In this embodiment, the rotor seal 12b is assumed to be made of a material such as stainless steel, ceramic, or resin. Furthermore, for rotor seals 12b made of metal or ceramic, a surface coated with diamond-like carbon can also be used. The upper surface of the rotor seal 12b has a flow channel groove 32 and a wear chip discharge groove 33, which will be explained in detail later.

[0019] The rotor 12 is arranged coaxially with the stator 11, and the rotor seal 12b is in contact with the rotor contact portion 11b of the stator 11. Furthermore, the rotor 12 is able to rotate around its axis at a predetermined angle, as described later, by connecting a shaft 15 extending from a motor 17 with an encoder to the rotor body 12a.

[0020] Furthermore, the rotor 12 is configured such that the rotor seal 12b is pressed against the rotor contact portion 11b with a predetermined load by a biasing means 16 such as a spring. As a result, the flow channel groove 32 formed in the rotor seal 12b is sealed liquid-tight by the rotor contact portion 11b.

[0021] Next, the flow channel groove 32 and the wear chip discharge groove 33 formed in the rotor seal 12b will be described. Figure 2 is a partial top view of the rotor 12, showing only the rotor seal 12b portion of the rotor 12. In Figure 2, the reference numeral S2 indicates the sliding surface of the rotor 12 that slides against the rotor contact portion 11b of the stator 11, which is shown by the dashed line (two-dot dash line). For ease of drawing, the sliding surface S2 of the rotor 12 is shown with shading.

[0022] As shown in Figure 2, the flow channel groove 32 in this embodiment is formed as a groove that extends in an arc shape along the upper surface of the rotor seal 12b. Specifically, the flow channel groove 32 extends in the circumferential direction around the axis of the rotor seal 12b with a predetermined circumference, and is formed so that multiple grooves are arranged in the circumferential direction at predetermined intervals. The circumference, number, and position of each flow channel groove 32 can be set to correspond to the circumferential arrangement angle, number, and position of the liquid flow port 31a (see Figure 1) of the stator 11 (rotor contact portion 11b), as well as the rotation angle of the rotor 12. In this embodiment, the flow channel grooves 32 are assumed to be arranged in a manner of three grooves with a predetermined circumference and equal spacing in the circumferential direction, as shown in Figure 2. The positional relationship between the flow channel grooves 32 and the liquid flow port 31a (see Figure 1) of the rotor contact portion 11b (see Figure 1), and the rotation angle of the rotor 12 will be explained in detail later.

[0023] As shown in Figure 2, the wear chip discharge groove 33 is formed as a groove extending radially from the inside to the outside of the rotor seal 12b. In this embodiment, the wear chip discharge groove 33 has an oval shape (running track shape) with arc portions at both ends in the longitudinal direction when viewed from above. Furthermore, one end of the wear chip discharge groove 33 formed radially inward is located within the sliding surface S2 of the rotor 12, while the other end of the wear chip discharge groove 33 formed radially outward faces the outside of the sliding surface S2. More specifically, in this embodiment, the wear chip discharge groove 33 has one radially inner end (inner circumferential end) located outside the flow channel groove 32, and the other radially outer end (outer circumferential end) located outside the sliding surface S2. That is, the other end (outer circumferential end) of the wear chip discharge groove 33 communicates with the gap between the stator 11 and the rotor 12 formed on the outside of the sliding surface S2.

[0024] In this embodiment, the wear chip discharge grooves 33 are assumed to be arranged in multiple equal intervals in the circumferential direction of the rotor seal 12b. Specifically, the wear chip discharge grooves 33 are assumed to be arranged at intervals less than or equal to a predetermined rotation angle of the rotor 12. Incidentally, the predetermined rotation angle of the rotor 12 in this embodiment is assumed to be 60 degrees, as will be described later. Therefore, the wear chip discharge grooves 33 in this embodiment are arranged at equal intervals in the circumferential direction with a distance of 60 degrees or less between adjacent grooves.

[0025] In other words, in the example shown in Figure 2, the wear chip discharge grooves 33 are arranged in a circumferential direction with seven grooves spaced 51.4 degrees apart. The number of wear chip discharge grooves 33 will be explained in detail later, but it can be set to one or more grooves as appropriate depending on the rotation angle of the rotor 12, which is set in advance. Also, in the configuration in which multiple wear chip discharge grooves 33 are arranged in the circumferential direction, the spacing between adjacent grooves is not limited to being equal.

[0026] Next, we will describe the multiple through holes 31 (see Figure 1) that penetrate the stator 11 (see Figure 1) in the axial direction. Figure 3 is a partial bottom view of the stator 11, showing only the rotor contact portion 11b (see Figure 1). As shown in Figure 3, the lower surface of the rotor contact portion 11b forms the sliding surface S1 of the stator 11, which slides against the sliding surface S2 (see Figure 2) of the rotor seal 12b (see Figure 2). As shown in Figure 3, in this embodiment, the through holes 31 are formed so that there are six holes arranged at equal intervals (60-degree intervals) in the circumferential direction centered on the axis of the rotor contact portion 11b. Each of the six through holes 31 has a circular cross-section of the same diameter and forms a liquid flow port 31a that opens onto the sliding surface S1.

[0027] Next, the positional relationship between the liquid flow port 31a of the through hole 31 formed in the stator 11 (rotor contact portion 11b) and the flow channel groove 32 formed in the rotor 12 (rotor seal 12b) will be explained. Figure 4A shows the positional relationship between the stator 11 and the rotor 12 in contact with the stator 11 in the first position. Figure 4B shows the positional relationship between the stator 11 and the rotor 12 in contact with the stator 11 in the second position. Figures 4A and 4B correspond to the IV-IV cross section in Figure 1.

[0028] As shown in Figure 4A, the rotor 12 in the first position connects the through-hole 31 indicated by A and the through-hole 31 indicated by B of the stator 11 by the flow channel groove 32 indicated by X. The rotor 12 in the first position also connects the through-hole 31 indicated by C and the through-hole 31 indicated by D of the stator 11 by the flow channel groove 32 indicated by Y. The rotor 12 in the first position also connects the through-hole 31 indicated by E and the through-hole 31 indicated by F of the stator 11 by the flow channel groove 32 indicated by Z.

[0029] In this configuration, each of the six through-holes 31 has a liquid flow port 31a located at the respective circumferential ends of the three flow grooves 32. That is, the circumference of the arc-shaped flow groove 32 is set to correspond to the distance between liquid flow ports 31a arranged on a predetermined circumference. Specifically, the circumference of the flow groove 32 is set so that, when viewed from above the rotor 12, each of the adjacent liquid flow ports 31a fits within the respective ends of the flow groove 32. Furthermore, the distance of the flow channel groove 32 from the axis of the rotor 12 is set to match the distance of the liquid flow port 31a from the axis of the stator 11.

[0030] Next, we will describe the rotor 12 in the second position. As shown in Figure 4B, the second position of the rotor 12 is set by rotating the rotor 12 in the first position shown in Figure 4A at a preset rotation angle θ1 (60 degrees). The rotation angle θ1 of the rotor 12 is set to match the angle (60 degrees) of the fluid flow port 31a centered on the axis of the stator 11. That is, the rotation angle θ1 of the rotor 12 is 2π / M [radians], where M is the number of equally spaced fluid flow ports 31a.

[0031] As the rotor 12 changes from the first position to the second position, the flow channel groove 32 indicated by X, which connects the through hole 31 indicated by A and the through hole 31 indicated by B in Figure 4A, switches its flow channel so that it connects the through hole 31 indicated by B and the through hole 31 indicated by C, as shown in Figure 4B.

[0032] Furthermore, the flow channel groove 32 indicated by Y, which connects the through hole 31 indicated by C in Figure 4A and the through hole 31 indicated by D, switches the flow channel so that it connects the through hole 31 indicated by D and the through hole 31 indicated by E, as shown in Figure 4B. Furthermore, the flow channel groove 32 indicated by Z, which connects the through hole 31 indicated by E in Figure 4A with the through hole 31 indicated by F, switches the flow channel so that it connects the through hole 31 indicated by F with the through hole 31 indicated by A, as shown in Figure 4B.

[0033] Next, we will describe the displacement of the wear chip discharge groove 33 relative to the stator 11 (rotor contact portion 11b) when the rotor 12 changes from the first position to the second position. As shown in Figure 4B, for example, the wear chip discharge groove indicated by the dotted line 33X and the adjacent wear chip discharge groove 33X, also indicated by the dotted line 33Y, are separated by an interval of θ2 (51.4 degrees), as described above.

[0034] Then, when the rotor 12 rotates at a predetermined rotation angle θ1 (60 degrees), the wear chip discharge groove indicated by the dotted line 33X in Figure 4B (the wear chip discharge groove at the first position in Figure 4A) moves to the position of the wear chip discharge groove 33X indicated by the solid line (the wear chip discharge groove at the second position in Figure 4B) so that it opens at an angle of θ1 (60 degrees). On the other hand, in Figure 4B, the wear debris discharge groove labeled 33Y (the wear debris discharge groove at the first position in Figure 4A), indicated by a dotted line, moves to the position of the wear debris discharge groove 33Y (the wear debris discharge groove at the second position in Figure 4B), indicated by a solid line, opening at an angle of θ1 (60 degrees).

[0035] Therefore, in this flow path switching valve, when the rotor 12 rotates at a predetermined rotation angle θ1 (60 degrees) to switch the through-holes 31 that communicate with each other in the flow path groove 32, the range in which one wear particle discharge groove 33X rotates and the range in which the adjacent wear particle discharge groove 33Y rotates overlap. In other words, in this flow path switching valve 1, when the rotor 12 rotates at a predetermined rotation angle θ1 (60 degrees), each wear chip discharge groove 33 (see Figure 4A) works together to set the movement area of ​​the wear chip discharge groove 33 in the circumferential direction of the sliding surface S1 (see Figure 3) of the stator 11 without interruption.

[0036] (Liquid Chromatography) Next, a liquid chromatograph equipped with a flow path switching valve 1 (see Figures 4A and 4B) according to this embodiment will be described. Figure 5 is an explanatory diagram of the configuration of a liquid chromatograph 100 equipped with a flow path switching valve 1. In the flow path switching valve 1 shown in Figure 5, the flow path grooves 32 indicated by X (see Figure 4A), Y (see Figure 4A), and Z (see Figure 4A) of the rotor 12 in the first position are represented by solid lines. In addition, the flow path grooves 32 indicated by X (see Figure 4B), Y (see Figure 4B), and Z (see Figure 4B) in the second position, obtained by rotating the rotor 12 clockwise from the first position at an angle θ1 (see Figure 4B) toward the plane of the paper in Figure 5, are represented by dotted lines.

[0037] As shown in Figure 5, the liquid chromatograph 100 includes a needle 109 for supplying the sample 108 to be analyzed to the flow path switching valve 1, a suction pump 106, a liquid transfer pump 102 for supplying the eluent 101, which serves as a carrier for the sample 108, to the flow path switching valve 1, a separation column 103, a detector 104, and piping P connecting these to the flow path switching valve 1.

[0038] Specifically, the needle 109 of the liquid chromatograph 100 is connected to the aforementioned upper end of the through-hole 31 indicated by E via piping P1. The suction pump 106 is connected to the aforementioned upper end of the through-hole 31 indicated by D via piping P2. The liquid transfer pump 102 is connected to the aforementioned upper end of the through-hole 31 indicated by A via piping P3. The separation column 103 and the detector 104 are connected to the aforementioned upper end of the through-hole 31 indicated by B via piping P4. Furthermore, the aforementioned upper end of the through-hole 31 indicated by F in the liquid chromatograph 100 and the aforementioned upper end of the through-hole 31 indicated by C are connected by a sample loop P5 (for example, a hollow tube).

[0039] In such a liquid chromatograph 100, when the rotor 12 is in the first position and the liquid transfer pump 102 is driven, the eluent 101 is sent to pipe P4 via pipe P3, through-hole 31 indicated by A, flow channel groove 32 indicated by X, and through-hole 31 indicated by B. The eluent 101 flowing through pipe P4 passes through separation column 103 and detector 104 before being collected in waste liquid tank 105.

[0040] Furthermore, when the rotor 12 is in the first position and the suction pump 106 is driven, the sample 108 flows into the pipe P2 via the needle 109, the pipe P1, the through hole 31 indicated by E, the flow channel groove 32 indicated by Z, the through hole 31 indicated by F, the sample loop P5, the through hole 31 indicated by C, the flow channel groove 32 indicated by Y, and the through hole 31 indicated by D. When the sample 108 begins to be discharged from the pipe P2 into the waste liquid tank 107, the liquid transfer pump 102 and the suction pump 106 stop.

[0041] Next, when the rotor 12 rotates to the predetermined rotation angle θ1 (see Figure 4B) and is set to the second position, the flow channel groove 32 indicated by Y switches to connect the through hole 31 indicated by D and the through hole 31 indicated by E. Also, the flow channel groove 32 indicated by Z switches to connect the through hole 31 indicated by F and the through hole 31 indicated by A. As a result, the sample loop P5 is disconnected from the pipes P1 and P2 and filled with a predetermined amount of sample 108.

[0042] Furthermore, when the rotor 12 is set to the second position and the liquid delivery pump 102 starts to operate, the eluent 101 is delivered to the sample loop P5 via the piping P3, the through-hole 31 indicated by A, the flow channel groove 32 indicated by Z, and the through-hole 31 indicated by F. The eluent 101, which has been sent to the sample loop P5, flows into the through-hole 31 indicated by C, together with the sample 108 that was filling the sample loop P5.

[0043] The eluent 101 and sample 108 that flowed into the through-hole 31 indicated by C are sent to the piping P4 via the flow channel groove 32 indicated by X and the through-hole 31 indicated by B. The separation column 103 separates the analytes contained in the sample 108 through the interaction between the stationary phase and the mobile phase. The detector 104 outputs the detection signal of the separated analytes to a display device (not shown) or the like. The sample 108 and eluent 101 that have passed through the separation column 103 and detector 104 are collected in the waste liquid tank 105.

[0044] As described above, the flow path switching valve 1 of the liquid chromatograph 100, when the rotor 12 rotates at a rotation angle θ1 (60 degrees) to switch the flow path between the sample 108 and the eluent 101, moves the wear particle discharge groove 33 along the sliding surface S1 of the stator 11 (see Figure 3), thereby collecting and discharging wear particles from between the stator 11 and the rotor 12.

[0045] <Effects> Next, the effects and benefits of the flow path switching valve 1 and the liquid chromatograph 100 equipped with this flow path switching valve 1 according to this embodiment will be described. The flow path switching valve 1 according to this embodiment comprises a stator 11 and a rotor 12 that rotates while sliding against the stator 11. The stator 11 has a plurality of through holes 31, and the rotor 12 has flow path grooves 32 that communicate with the through holes 31. The sliding surface S2 of the rotor 12 has a wear debris discharge groove 33, one end of which is located within the sliding surface S2, and the other end of which faces the outside of the sliding surface S2.

[0046] In this flow path switching valve 1, each time the rotor 12 rotates and switches the flow path, the wear particle discharge groove 33 moves in the circumferential direction to collect wear particles generated on the sliding surfaces S1 and S2 between the stator 11 and the rotor 12. The collected wear particles are then discharged to the outside of the sliding surfaces S1 and S2 from the other end of the wear particle discharge groove 33. Unlike conventional flow path switching valves (see, for example, Patent Document 1), this flow path switching valve 1 and liquid chromatograph 100 do not require an additional liquid delivery mechanism and efficiently remove wear particles generated on the sliding surfaces S1 and S2 between the stator 11 and rotor 12. The flow path switching valve 1 efficiently prevents wear particles from accumulating on the sliding surfaces S1 and S2, thereby achieving a longer service life.

[0047] Furthermore, in such a flow path switching valve 1, the wear chip discharge grooves 33 are formed in a plurality of arrangements in the circumferential direction of the rotor 12 and are arranged at intervals of less than or equal to a predetermined rotation angle θ1 of the rotor 12. With this flow path switching valve 1 and liquid chromatograph 100, when the rotor 12 rotates at a rotation angle θ1 to switch the flow path, each of the multiple wear particle discharge grooves 33 cooperates to form a continuous movement trajectory around the entire circumference of the sliding surface S1 (see Figure 3) of the stator 11. As a result, the wear particle discharge grooves 33 efficiently collect and discharge wear particles.

[0048] Furthermore, in such a flow path switching valve 1, the wear chip discharge groove 33 is located on the outer circumference side of the flow path groove 32. As a result, the wear chip discharge groove 33 can efficiently collect and discharge wear chips that are generated in greater quantities on the outer circumference side of the sliding surfaces S1 and S2 than on the inner circumference side. Incidentally, the outer circumference of the sliding surfaces S1 and S2 tends to generate more wear particles compared to the inner circumference due to the larger circumferential displacement caused by rotation and uneven surface pressure resulting from the uneven application of pressure to each flow path.

[0049] Furthermore, since the wear chip discharge groove 33 is located on the outer circumference of the flow channel groove 32, it does not interfere with the flow channel groove 32 or the through hole 31 of the stator 11 when the rotor 12 rotates. This ensures that the liquid-tightness of the flow channel formed by the flow channel groove 32 and the through hole 31 is maintained.

[0050] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. The first to tenth modified examples of the flow path switching valve 1 of the above embodiment will be described with reference to Figures 6 to 16. In these modified examples, the same reference numerals are used for components that are the same as in the above embodiment, and their detailed descriptions are omitted.

[0051] In the above embodiment, when the predetermined rotation angle θ1 of the rotor 12 is set to 60 degrees, the wear chip discharge grooves 33 are arranged at intervals of θ2 (in the example shown in Figure 4B, θ2 is 51.4 degrees) that is less than or equal to the rotation angle of the rotor 12. In other words, the spacing θ2 of the wear chip discharge grooves 33 can be set to be equal to the rotation angle θ1 of the rotor 12 (θ2 = θ1).

[0052] Figure 6 is an explanatory diagram of the configuration of a first modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment. As shown in Figure 6, in the first modified example of the flow path switching valve 1, when the predetermined rotation angle θ1 of the rotor 12 is set to 60 degrees, six wear chip discharge grooves 33 are arranged at equal intervals in the circumferential direction. That is, in the example shown in Figure 6, the interval θ2 of the wear chip discharge grooves 33 is set to 60 degrees, which is equal to the rotation angle θ1 (60 degrees) of the rotor 12. According to this first modified flow path switching valve 1, when the rotation angle θ1 of the rotor 12 is set to 60 degrees, the minimum number of wear chip discharge grooves 33 allows for the formation of a continuous movement trajectory of the wear chip discharge grooves 33 in the circumferential direction of the sliding surface S1 with the stator 11.

[0053] Furthermore, although the wear chip discharge groove 33 (see Figure 4A) in the above embodiment has an oval shape (running track shape) in plan view, the planar shape of the wear chip discharge groove 33 is not limited to this. Figure 7 is an explanatory diagram of the configuration of a second modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment. Figure 8 is an explanatory diagram of the configuration of a third modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment. In these second and third modified examples, six wear chip discharge grooves 33 are arranged at equal intervals in the circumferential direction, similar to the first modified example (see Figure 6).

[0054] As shown in Figure 7, the wear chip discharge groove 33 in the second modified example has a rectangular planar shape, unlike the wear chip discharge groove 33 in the above embodiment (see Figure 4A). In this second modified example, the wear chip discharge groove 33 can be made larger in opening area on the upper surface compared to the wear chip discharge groove 33 of the above embodiment which has the same groove width and length, thus providing superior wear chip recovery efficiency.

[0055] Furthermore, as shown in Figure 8, the wear debris discharge groove 33 in the third modified example differs from the wear debris discharge groove 33 in the above embodiment (see Figure 4A) in that it has a fan-shaped planar shape that widens from the radially inward (inner circumference) side of the rotor seal 12b to the radially outward (outer circumference) side. Also, unlike the wear debris discharge groove 33 in the above embodiment (see Figure 4A), the wear debris discharge groove 33 in the third modified example extends to the outer peripheral edge of the rotor seal 12b and opens to the circumferential surface of the rotor seal 12b.

[0056] In the second modified example, the wear particle discharge groove 33 has a fan-shaped planar shape that widens radially outward (towards the outer circumference) and extends to the outer edge of the rotor seal 12b, thus providing excellent wear particle recovery efficiency on the outer circumference side, where more wear particles tend to be generated compared to the inner circumference side of the stator 11. Furthermore, in the second modified example, the wear particle discharge groove 33 opens to the circumferential surface of the rotor seal 12b, resulting in excellent wear particle discharge efficiency by discharging the collected wear particles from the wear particle discharge groove 33 toward the outside of the rotor seal 12b.

[0057] Figure 9 is an explanatory diagram of the configuration of a fourth modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment. As shown in Figure 9, in the fourth modified flow path switching valve 1, only one flow path groove 32 is formed so as to extend radially outward from the center of the rotor seal 12b in a plan view. Furthermore, in the fourth modified example, the through-hole 31 of the stator 11 consists of one through-hole 31α located in the center and five through-holes 31β arranged at equal intervals on the circumference centered on this through-hole 31α. In Figure 9, the four through-holes 31β other than the one facing the foreground of the paper in Figure 9 via the flow channel groove 32 of the rotor seal 12b are shown as hidden lines (dotted lines).

[0058] The flow channel groove 32 is arranged to connect the central through hole 31α with the through holes 31β arranged around the circumference. In other words, the flow path switching valve 1 of the fourth modified example is configured to connect the central through-hole 31α with the through-holes 31β arranged on the circumference each time the rotor 12 rotates 72 degrees. Furthermore, in the fourth modified example, as shown in Figure 9, only one wear chip discharge groove 33 is formed on the outer circumference side of the through hole 31β. The wear chip discharge groove 33 is formed in the rotor seal 12b such that one end is located within the sliding surface S1 of the stator 11 and the other end faces the outside of the sliding surface S1.

[0059] With this fourth modified example of the flow path switching valve 1, one of the two through holes 31 connected by the flow path groove 32 can be limited to the central through hole 31α. Therefore, the number of through holes 31β to which the other end of the flow path groove 32 is connected can be freely increased or decreased, not limited to the aforementioned five. Furthermore, this fourth modified example of the flow path switching valve 1 assumes that the rotor 12 rotates at least 360 degrees in order for the wear particle discharge groove 33 to collect and discharge the wear particles generated between the stator 11 and the rotor 12. In other words, this fourth modified example of the flow path switching valve 1 is assumed to perform the rotation process of the rotor 12 that performs the flow path switching and the rotation process of the rotor 12 that discharges wear particles at different timings.

[0060] Figure 10 is an explanatory diagram of the configuration of a fifth modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment. In this fifth modified example, as with the first modified example (see Figure 6), six wear chip discharge grooves 33 are arranged at equal intervals in the circumferential direction. As shown in Figure 10, in the fifth modified flow path switching valve 1, the rotor seal 12b further has a wear chip discharge groove (inner circumferential wear chip discharge groove) 33a that extends radially around the rotor 12 on the inner circumferential side of the flow path groove 32.

[0061] In this fifth modified example, the wear particle discharge groove 33a of the flow path switching valve 1 is located on the inner circumference side, where the amount of wear particle generation is less than on the outer circumference side, and is configured to retain the wear particle discharged from the sliding surface S1 within the wear particle discharge groove 33a. According to this fifth modified example of the flow path switching valve 1, in addition to the wear particle discharge groove 33 located on the outer circumference of the flow path groove 32, there is also a wear particle discharge groove 33a on the inner circumference of the flow path groove 32, which further improves the efficiency of collecting wear particles between the stator 11 and the rotor 12.

[0062] Figure 11 is an explanatory diagram of the configuration of a sixth modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment. As shown in Figure 11, the sixth modified flow path switching valve 1 has six wear chip discharge grooves 33 spaced equally apart in the circumferential direction of the rotor seal 12b. In the sixth modified example, the wear debris discharge groove 33 extends from the center of the rotor seal 12b to the outside of the sliding surface S1 of the stator 11, such that one of the six wear debris discharge grooves 33b passes between two adjacent flow grooves 32.

[0063] In other words, in the sixth modified example of the flow path switching valve 1, at least one of the multiple wear particle discharge grooves 33 has one end of the wear particle discharge groove 33 located on the inner circumference side of the flow path groove 32. According to this sixth modified example of the flow path switching valve 1, by having a wear particle discharge groove 33b that is radially longer than the wear particle discharge groove 33, the efficiency of wear particle collection between the stator 11 and the rotor 12 can be further improved.

[0064] Furthermore, in the sixth modified example, as shown in Figure 11, when the rotor 12 rotates and switches the flow path, the wear debris discharge groove 33b moves to the position of the wear debris discharge groove 33b indicated by the dotted line in Figure 11, and intersects with the through hole 31b and the through hole 31c of the stator 11. In the sixth modified example, through-holes 31b and 31c are assumed to be, for example, drainage channels for waste liquid, which do not affect the analysis. Through-holes 31b and 31c are intended to be used as discharge channels for wear particles collected by the wear particle discharge groove 33b.

[0065] In other words, in this sixth modified flow path switching valve 1, the wear particle discharge groove 33b formed inside the flow path groove 32 intersects with and conducts only to specific through holes 31b and 31c of the stator 11 due to the rotation of the rotor 12. According to this sixth modified example of the flow path switching valve 1, specific through holes 31b and 31c can be used as discharge paths for wear particles collected by the wear particle discharge groove 33b.

[0066] Next, a seventh modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment will be described. Figure 12A is a partial top view of the rotor 12 in the seventh modified example. Figure 12B is a partial bottom view of the stator 11 in the seventh modified example. As shown in Figure 2, the wear debris discharge groove 33 of the flow path switching valve 1 according to the above embodiment is formed only on the rotor seal 12b of the rotor 12, and as shown in Figure 3, the wear debris discharge groove 33 is not formed on the stator 11 side.

[0067] In contrast, the rotor seal 12b of the seventh modified example does not have a wear chip discharge groove 33, as shown in Figure 12A. In the seventh modified example, the wear chip discharge groove 33 is formed only on the stator 11, as shown in Figure 12B. In this seventh modified example, as in the first modified example (see Figure 6), six wear chip discharge grooves 33 are arranged at equal intervals in the circumferential direction. Specifically, the wear chip discharge groove 33 of the stator 11 extends radially from the sliding surface S1 with the rotor seal 12b to the outside of this sliding surface S1, on the outer circumference side of the through hole 31. According to this seventh modified example of the flow path switching valve 1, since a wear particle discharge groove 33 is formed on the fixed stator 11 side, the wear particles collected in the wear particle discharge groove 33 can be stably discharged to the outside of the sliding surface S1.

[0068] Next, an eighth modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment will be described. Figure 13A is a partial top view of the rotor 12 in the eighth modified example. Figure 14B is a partial bottom view of the stator 11 in the eighth modified example. As shown in Figure 13A, the rotor seal 12b in the eighth modified example has the same configuration as the rotor seal 12b in the first modified example shown in Figure 6. That is, as shown in Figure 13A, the wear chip discharge grooves 33 are arranged at equal intervals in the circumferential direction, six of them extending from the sliding surface S2 to the outside of the sliding surface S2 on the outer circumference side of the flow channel groove 32.

[0069] Furthermore, in the eighth modified example, the stator 11 is arranged at equal intervals in the circumferential direction, with six stators 11 extending from the sliding surface S1 to the outer edge of the sliding surface S1 on the outer circumference side of the through hole 31. In other words, the flow path switching valve 1 of the eighth modified example has wear chip discharge grooves 33 formed in both the stator 11 and the rotor 12. With this eighth modified example of the flow path switching valve 1, since wear particle discharge grooves 33 are formed in both the stator 11 and the rotor 12, the efficiency of wear particle collection between the stator 11 and the rotor 12 can be further increased.

[0070] Figure 14 is an explanatory diagram of the configuration of a ninth modified example of the flow path switching valve 1 (see Figure 4A) according to the above embodiment. In this ninth modified example, as with the first modified example (see Figure 6), six wear chip discharge grooves 33 are arranged at equal intervals in the circumferential direction. As shown in Figure 14, in the ninth modified flow path switching valve 1, both ends of the flow path groove 32 are in contact with the through hole 31, but the middle part has a shape that bends inward. The flow path groove 32 is curved so as to be convex inward when viewed from above. In other words, in the flow path switching valve 1 according to the ninth modified example, the flow path groove 32 of the rotor 12 is bent inward in the middle portion rather than at both ends that communicate with the through hole 31, and the wear chip discharge groove 33 is positioned close to the bent middle portion of the flow path groove 32. As a result, even if the flow path switching valve 1 extends the wear debris discharge groove 33 further inward than the flow path switching valve 1 according to the first modified example (see Figure 6), it is possible to expand the range over which the wear debris discharge groove 33 collects wear debris while maintaining a distance that prevents electrical contact between the wear debris discharge groove 33 and the flow path groove 32.

[0071] Figure 15 is an explanatory diagram of the configuration of a tenth modified example of the flow path switching valve 1 (see Figure 1) according to the above embodiment. As shown in Figure 15, the flow path switching valve 1 of the 10th modified example has a control unit 18 that controls the driving timing of the motor 17. Specifically, the control unit 18 is configured to control the timing of the execution of the rotor 12's flow path switching operation, which switches the electrical connection between the through-hole 31 of the stator 11 and the flow path groove 32 of the rotor 12, and the rotor 12's wear powder discharge operation, which discharges wear powder from the sliding surfaces S1 and S2 using the wear powder discharge groove 33. Note that the wear particle discharge operation here is set separately from the flow path switching operation, and does not include the wear particle discharge operation by the rotor 12 that is performed together with the flow path switching operation as described above.

[0072] In the tenth modified example, the wear particle discharge operation may include, for example, the case in which a wear particle discharge groove 33 formed at a predetermined position is rotated 360 degrees by the rotor 12 from its initial position (reference position). However, the wear particle discharge operation is not limited to an operation solely for the purpose of collecting and discharging wear particles, but can also serve as an operation of the rotor 12 for other purposes, such as the rotor 12 returning to its home position. Such a control unit 18 can be configured to include a ROM (Read Only Memory) for storing a predetermined program, a RAM (Random Access Memory) for reading and expanding the program stored in the ROM, and a CPU (Central Processing Unit) for executing the expanded program and outputting commands to the motor 17.

[0073] Figure 16 is a flowchart showing the specific steps performed by the control unit 18 (see Figure 15). For example, when the analysis of sample 108 by the liquid chromatograph 100 (see Figure 5) begins, the control unit 18 (see Figure 15) outputs a wear particle discharge operation command as shown in Figure 15 (step S101). Specifically, the control unit 18 (see Figure 15) outputs a command to the motor 17 (see Figure 15) to rotate the rotor 12 (see Figure 15) at least 360 degrees. As a result, the space between the sliding surface S1 of the stator 11 (see Figure 15) and the sliding surface S of the rotor 12 (see Figure 15) becomes clean and free of wear particles.

[0074] Next, the control unit 18 (see Figure 15) outputs a flow path switching operation command as shown in Figure 16 (step S102). Specifically, the control unit 18 (see Figure 15) outputs a command to the motor 17 (see Figure 15) to rotate the rotor 12 and perform the necessary multiple flow path switching during the analysis process of the sample 108 (see Figure 5) by the liquid chromatograph 100 (see Figure 5).

[0075] Next, the control unit 18 determines whether a predetermined number of flow path switching operations have been performed since the previous wear particle discharge operation (step S103). If the control unit 18 determines that a predetermined number of flow path switching operations have been performed (Yes in step S103), it outputs a wear particle discharge operation command (step S104), and then executes the next step S105. Furthermore, if the control unit 18 determines in step S103 that a predetermined number of flow path switching operations have not been performed (No. in step S103), it executes the next step S105 without going through step S104.

[0076] In step S105, the control unit 18 determines whether the sample analysis by an analytical instrument, such as a liquid chromatograph 100 (see Figure 5), has been completed. If the control unit 18 determines that the sample analysis by the analytical instrument has not been completed (No. in step S105), it returns to step S102 and repeats the procedure from step S102 to step S105. Then, if the control unit 18 determines in step S105 that the sample analysis by the analyzer has been completed (Yes in step S105), it outputs a wear particle discharge operation command (step S106), and then terminates this control process.

[0077] In addition, in step S103 of the procedure executed by the control unit 18, the condition for determination can be changed from "whether a predetermined number of flow path switching operations have been performed since the previous wear dust discharge operation" to "whether a predetermined time has elapsed since the previous wear dust discharge operation was performed."

[0078] The operation of the flow path switching valve 1 can be achieved not only by the control method of the control unit 18 shown in Figure 15, but also by manual operation by the user. In other words, the specific operation method of the flow path switching valve 1 includes a flow path switching step by the rotor 12 that switches the conductivity between the through hole 31 of the stator 11 and the flow path groove 32 of the rotor 12, and a wear powder discharge step by the rotor 12 that discharges wear powder from the sliding surfaces S1 and S2 through the wear powder discharge groove 33.

[0079] Furthermore, in the operation method of this flow path switching valve, the timing for performing the wear particle discharge process is at least one of the following: at the start of the analysis work by the analytical device equipped with the flow path switching valve, at the end of the analysis work, at any time the user of the flow path switching valve performs the operation, after a predetermined number of flow path switching processes have been performed since the previous wear particle discharge process in the case of multiple wear particle discharge processes, and after a certain amount of time has elapsed since the previous wear particle discharge process in the case of multiple wear particle discharge processes.

[0080] This method of operating the flow path switching valve 1 does not require an additional fluid supply mechanism, efficiently removes wear particles generated on the sliding surface between the stator and rotor, effectively prevents wear particles from accumulating on the sliding surface, and ultimately achieves a longer service life. [Explanation of Symbols]

[0081] 1. Flow path switching valve 11 stata 12 rotors 18 Control Unit 31 Through hole 32 channel grooves 33 Wear chip discharge groove 100 Liquid Chromatographs S1 sliding surface S2 sliding surface

Claims

1. stator and, The system comprises a rotor that rotates while sliding in contact with the stator, The stator has a plurality of through holes, The rotor has a flow channel groove that communicates with the through hole, The rotor and the stator have wear chip discharge grooves on at least one of their sliding surfaces. A flow path switching valve wherein one end of the wear debris discharge groove is located within the sliding surface, and the other end of the wear debris discharge groove faces the outside of the sliding surface.

2. The flow path switching valve according to claim 1, characterized in that the wear chip discharge grooves are formed in a plurality of arrangements in the circumferential direction of the rotor and are arranged at intervals less than or equal to the rotation angle of the rotor.

3. The flow path switching valve according to claim 2, characterized in that at least one of the wear debris discharge grooves has one end located on the inner circumference side of the flow path groove.

4. The flow path switching valve according to claim 3, characterized in that the wear particle discharge groove, one end of which is located on the inner circumference side of the flow path groove, is formed to intersect and conduct electricity only with a specific through hole of the stator due to the rotation of the rotor.

5. The flow path switching valve according to claim 1, comprising a control unit that controls the timing of the execution of a rotor flow path switching operation that switches electrical contact between the through hole of the stator and the flow path groove of the rotor, and a rotor wear particle discharge operation that discharges wear particles from the sliding surface through the wear particle discharge groove.

6. The flow path switching valve according to claim 1, characterized in that the flow path groove of the rotor is bent inward in the middle portion than the ends that communicate with the through hole, and the wear chip discharge groove is arranged to be close to the bent middle portion of the flow path groove.

7. A method for operating a flow path switching valve according to claim 1, A flow path switching step by the rotor, which switches the electrical connection between the through hole of the stator and the flow path groove of the rotor, A wear particle discharge step by the rotor, in which wear particles are discharged from the sliding surface through the wear particle discharge groove, A method for operating a flow path switching valve having a flow path switching valve.

8. The timing for performing the wear dust removal process is, The method for operating a flow path switching valve according to claim 7, characterized in that the timing is at least one of the following: when an analytical device equipped with a flow path switching valve starts an analytical operation, when an analytical device starts an analytical operation, when the user of the flow path switching valve performs an arbitrary operation, after a predetermined number of flow path switching operations have been performed since the execution of the previous wear particle discharge process in the case of multiple wear particle discharge processes, and after a certain period of time has elapsed since the execution of the previous wear particle discharge process in the case of multiple wear particle discharge processes.

9. A liquid chromatograph comprising a flow path switching valve according to any one of claims 1 to 6.

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