Teaching device and teaching method for multi-port valve

Abstract

This teaching device is for setting a reference position of a rotor (16) of a multi-port valve (2) configured so as to switch, according to rotation of the rotor (16), a communication state between a plurality of connection ports (14) for fluidly connecting piping. The teaching device comprises: the multi-port valve (2); a control unit (12) that controls the operation of the multi-port valve (2); and sensors (8; 30) provided so that an output signal changes according to the position of the rotor (16) of the multi-port valve (2). The control unit (12) is configured to rotate the rotor (16) by small angles while reading the output signal of the sensors (8; 30) in teaching for setting the reference position of the rotor (16), and to set the reference position on the basis of the value of the output signal of the sensors (8; 30).

Description

Teaching device and teaching method for multi-port valve

[0001] The present invention relates to a teaching device and a teaching method for a multiport valve used in, for example, a high performance liquid chromatograph (hereinafter referred to as HPLC).

[0002] A multiport valve includes a valve head provided with multiple connection ports to which pipes are connected, and a rotor that rotates relative to the valve head (see Patent Document 1). The rotor is provided with flow paths that allow fluid communication between the connection ports of the valve head, and by rotating the rotor and changing its position relative to the valve head, the combination of connection ports that are fluidly connected to each other can be switched.

[0003] The relative position of the rotor with respect to the valve head is controlled by the rotor's rotation angle from a predetermined reference position, which is stored in the controller that controls the multiport valve by teaching, which is performed during assembly of the multiport valve, for example.

[0004] International Publication No. 2019 / 043908

[0005] In teaching to set the rotor's reference position, an operator typically visually aligns the reference points on the rotor and valve head. However, this teaching method, in which an operator visually aligns the reference points on the rotor and valve head, is prone to variations in alignment accuracy due to factors such as the operator's skill, making it difficult to maintain consistent quality in multiport valves.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to enable teaching of a multi-port valve to be performed without relying on visual inspection by an operator.

[0007] The teaching device of the present invention is a teaching device for setting a reference position of a rotor of a multiport valve configured to switch the communication state between multiple connection ports for fluidly connecting piping as the rotor rotates, and comprises: the multiport valve; a control unit that controls the operation of the multiport valve; and a sensor that is configured to change its output signal depending on the position of the rotor of the multiport valve, and the control unit is configured, during teaching to set the reference position of the rotor, to rotate the rotor by small angles while reading the output signal of the sensor, and set the reference position based on the value of the output signal of the sensor.

[0008] The teaching method of the present invention is a teaching method for setting a reference position of a rotor of a multi-port valve configured to switch the communication state between multiple connection ports for fluidly connecting piping as the rotor rotates, and includes providing a sensor so that the output signal changes depending on the position of the rotor, rotating the rotor by small angle increments while reading the output signal of the sensor, and setting the reference position based on the value of the output signal of the sensor.

[0009] According to the teaching device of the present invention, a sensor is provided so that the output signal changes depending on the position of the rotor, and during teaching, the rotor is rotated by small angles while reading the output signal of the sensor, and a reference position is set based on the value of the output signal of the sensor, so that the reference position of the rotor can be set without the operator having to visually check it.

[0010] According to the teaching method of the present invention, a sensor is provided so that the output signal changes depending on the rotor position, the rotor is rotated by small angles while reading the output signal of the sensor, and a reference position is set based on the value of the output signal of the sensor, so that the reference position of the rotor can be set without relying on visual inspection by an operator.

[0011] FIG. 1 is a schematic diagram of a teaching device that utilizes a liquid feed pump and a pressure sensor. FIG. 2 is a flowchart showing an example of a teaching method using the teaching device of the same embodiment. FIG. 3 is a diagram showing an example of the positional relationship between portholes and rotor grooves when the rotor is at a predetermined position. FIG. 4 is a diagram showing a state when the rotor is rotated counterclockwise and a first position of the rotor is detected. FIG. 5 is a diagram showing a state when the rotor is rotated clockwise and a second position of the rotor is detected. FIG. 6 is a diagram showing a state when the rotor is set to a reference position. FIG. 7 is a diagram showing the relationship between the rotation angle of the rotor from a predetermined position and the liquid feed pressure of the liquid feed pump. FIG. 8 is a partially exploded view of a multiport valve for explaining an embodiment of a teaching device and teaching method that utilizes an optical sensor. FIG. 9 is a cross-sectional view of the multiport valve of the same embodiment.

[0012] A teaching device and a teaching method for setting a reference position of a rotor according to the present invention will be described below with reference to the drawings.

[0013] FIG. 1 shows a schematic configuration of the teaching device.

[0014] The multiport valve 2 to be taught has a plurality of connection ports 14 (six in this embodiment) for connecting pipes, and a rotor 16 provided with grooves 18 for communicating between adjacent connection ports 14. The mutual communication state of the plurality of connection ports 14 is switched by rotating the rotor 16. In this embodiment, teaching means setting a reference position for the rotor 16.

[0015] In addition to the target multiport valve 2, the teaching device also includes a liquid feed flow path 4, a liquid destination flow path 10, and a control unit 12. The liquid feed flow path 4 and the liquid destination flow path 10 are connected to two of the connection ports 14 of the multiport valve 2 that are fluidly connected to each other when the rotor 16 is at the reference position. Hereinafter, these two connection ports 14 will be referred to as the pump port 14a and the liquid destination port 14b, respectively. A liquid feed pump 6 and a pressure sensor 8 are provided on the liquid feed flow path 4, and the liquid destination flow path 10 is connected to a drain.

[0016] The liquid delivery pump 6 delivers a liquid (e.g., water, a mobile phase for liquid chromatography, etc.), and the pressure sensor 8 outputs a signal corresponding to the liquid delivery pressure of the liquid delivery pump 6 to the control unit 12. When the rotor 18 of the multiport valve 2 is rotated while the liquid delivery pump 6 is delivering liquid, the liquid delivery pressure changes depending on the state of communication between the pump port 14a and the liquid delivery destination port 14b. In other words, the pressure sensor 8 is a sensor provided so that its output signal changes depending on the position of the rotor 16.

[0017] The control unit 12 reads the liquid delivery pressure based on the output signal from the pressure sensor 8, and controls the operations of the multiport valve 2 and the liquid delivery pump 6. The control unit 12 is realized by an electronic circuit equipped with a CPU (Central Processing Unit) and the like.

[0018] A teaching method using the teaching device of this embodiment will be described with reference to the flowchart of Figure 2 together with Figure 1. In the following description, Figures 3 to 7 will be referred to as necessary.

[0019] As a premise, when the multiport valve 2 is assembled, the rotor 16 is adjusted to be approximately in a reference position. The reference position of the rotor 16 is the position where one groove 18 completely covers (see FIG. 6) two portholes 15 in the stator (see 22 in FIG. 8) that respectively lead to two adjacent connection ports 14. Here, the position of the rotor 16 that is adjusted from the time of assembly of the multiport valve 2 is referred to as the "default position."

[0020] When teaching is started, the control unit 12 causes the liquid feed pump 6 to start feeding liquid at a predetermined flow rate with the rotor 16 at a specified position (steps 101 and 102). The control unit 12 then reads the liquid feed pressure based on the output signal from the pressure sensor 8 (step 103) and compares the read liquid feed pressure value with a preset threshold value (step 104). This threshold value is set to a value higher than the liquid feed pressure value when the liquid feed pump 6 feeds liquid at a predetermined flow rate with fluid communication substantially established between the pump port 14a and the liquid destination port 14b.

[0021] When the rotor 16 is in its default position, as shown in FIG. 3 , the groove 18 is almost always shifted in one direction from its reference position. Thus, even if either the porthole 15a leading to the pump port 14a or the porthole 15b leading to the destination port 14b is blocked to some extent, as long as the percentage of blockage is below a certain level, the flow resistance within the multiport valve 2 will not be extremely high, and normal fluid communication between the pump port 14a and the destination port 14b will be substantially established. On the other hand, if the rotor 16 is significantly shifted from its default position, which is the position at the time of assembly of the multiport valve 2, either the porthole 15a or the porthole 15b will be blocked to a certain level or more, preventing normal fluid communication between the pump port 14a and the destination port 14b, and increasing the flow resistance within the multiport valve 2. In this state, when the liquid feed pump 6 delivers liquid at a predetermined flow rate, the liquid feed pressure will be extremely high and exceed a preset threshold. In this embodiment, when the rotor 16 is in a predetermined position, which is the state when the multiport valve 2 is assembled, if the liquid delivery pressure exceeds the threshold value (step 104: Yes), the multiport valve 2 is determined to be defective (step 105).

[0022] If the liquid delivery pressure does not exceed the threshold value in step 104 (step 104: No), the controller 12 rotates the rotor 16 in one direction by small angle increments (e.g., by one to several pulses of the stepping motor that drives the rotor 16) while monitoring the liquid delivery pressure (steps 106 to 108). As the rotor 16 is rotated in one direction, if either the porthole 15a or 15b (porthole 15a in FIG. 4) becomes blocked to a certain degree or more, as shown in FIG. 4, the liquid delivery pressure rises sharply and exceeds the threshold value (see FIG. 7). The controller 12 stores the position of the rotor 16 (e.g., the rotation angle of the rotor from a specified position) when the liquid delivery pressure exceeds the threshold value as a first position (step 109).

[0023] Next, the control unit 12 rotates the rotor 16 in the other direction by small angle increments (for example, by one to several pulses of the stepping motor that drives the rotor 16) while monitoring the liquid delivery pressure (steps 110 to 112). As the rotor 16 is rotated in one direction, if either the porthole 15a or 15b (porthole 15b in FIG. 5) becomes blocked to a certain degree or more, as shown in FIG. 5, the liquid delivery pressure rises sharply and exceeds the threshold value (see FIG. 7). The control unit 12 stores the position of the rotor 16 when the liquid delivery pressure exceeds the threshold value as a second position (step 113).

[0024] After the first and second positions have been searched for, the control unit 12 sets the intermediate position between the first and second positions as the reference position (step 114), as shown in Fig. 7. This completes the teaching of the multiport valve 2.

[0025] In the above embodiment, the first and second positions are the positions of the rotor 16 when the rotor grooves 18 transition from a state in which the portholes 15 a and 15 b are substantially fluidly connected to a state in which they are not fluidly connected, but the present invention is not limited to this. Conversely, the positions of the rotor 16 when the rotor 16 is rotated by small increments of an angle to transition from a state in which the portholes 15 a and 15 b are not fluidly connected to a state in which they are fluidly connected may be searched for based on whether the liquid delivery pressure falls below a threshold value or becomes the smallest, and these positions may be designated as the first and second positions.

[0026] The above is an example of a teaching device and teaching method that uses a liquid delivery pump and a pressure sensor, but the present invention is not limited to this and can also include a teaching device and teaching method that uses an optical sensor to rotate the rotor 16 while checking the light intensity and searching for a first position and a second position, and sets the intermediate position between the first position and the second position as the reference position.

[0027] An embodiment of a teaching device and teaching method using an optical sensor will be described with reference to FIGS. 8 and 9. FIG.

[0028] As shown in Figures 8 and 9, the multiport valve 2 is constructed by attaching a valve head 2a to the top of a valve body 2b. The connection ports 14 are provided on the upper surface of the valve head 2. A rotor shaft 21 is arranged inside the valve body 2b so as to extend vertically. A disk-shaped stator 22 is attached to the valve head 2a. A flow path from the connection ports 14 reaches the underside of the valve head 2a, and the stator 22 is provided with portholes 15 that connect the flow path from the connection ports 14 of the valve head 2a to the rotor 16. The rotor 16 is attached to the upper end of the rotor shaft 21. Although not shown, the lower end of the rotor shaft 21 is connected to the motor shaft of a stepping motor, and the rotation of the stepping motor is transmitted to the rotor 16.

[0029] In order to utilize an optical sensor for teaching, a through hole 20 is provided that passes vertically through the valve head 2a, and a notch 24 is provided on the periphery of the rotor 16 that is positioned directly below the through hole 20 when the rotor 16 is in the reference position.

[0030] A sensor holder 26 is attached to the multiport valve 2, which holds an optical sensor consisting of a light-emitting element 28 and a light-receiving element 30. The sensor holder 26 holds the light-emitting element 28 facing vertically upward below the peripheral edge of the rotor 16, and holds the light-receiving element 30 facing vertically downward above the upper end of the through-hole 20.

[0031] Using the multiport valve 2 having the above configuration, when the rotor 16 is rotated by small angle increments while the light-emitting element 28 is turned on and the intensity of light from the light-emitting element 28 detected by the light-receiving element 30 is monitored, the intensity of light from the light-emitting element 28 detected by the light-receiving element 30 will be maximized when the notch 24 provided in the rotor 16 is positioned directly below the through-hole 20, i.e., when the rotor 16 is at the reference position. Therefore, by rotating the rotor 16 by small angle increments from a predetermined position and searching for the position where the intensity of light from the light-emitting element 28 detected by the light-receiving element 30 is maximized, the reference position of the rotor 16 can be easily found and set.

[0032] The above is an example of a teaching device and teaching method that uses an optical sensor, but the present invention is not limited to this and can also include a teaching device and teaching method that uses a liquid delivery pump and a pressure sensor to rotate the rotor 22 and set the position where the liquid delivery pressure is at its minimum as the reference position.

[0033] The examples described above are merely illustrative of embodiments of the teaching device and teaching method according to the present invention, and other embodiments of the teaching device and teaching method according to the present invention are as follows.

[0034] One embodiment of the teaching device of the present invention is a teaching device for setting a reference position of a rotor of a multiport valve configured to switch the communication state between multiple connection ports for fluidly connecting piping as the rotor rotates, and comprises: the multiport valve; a control unit that controls the operation of the multiport valve; and a sensor that is configured to change its output signal depending on the position of the rotor of the multiport valve, and the control unit is configured to, during teaching to set the reference position of the rotor, rotate the rotor by small angles while reading the output signal of the sensor, and set the reference position based on the value of the output signal of the sensor.

[0035] In aspect [1] of the above embodiment of the teaching device of the present invention, the control unit is configured to execute: a first search step of rotating the rotor in one direction by small angle increments to search for a first position of the rotor at which the output signal of the sensor changes; a second search step of rotating the rotor in another direction opposite to the one direction by small angle increments to search for a second position of the rotor at which the output signal of the sensor changes; and a reference position setting step of setting an intermediate position between the first position searched for in the first search step and the second position searched for in the second search step as the reference position of the rotor.

[0036] In the above aspect [1], the control unit may be configured to hold a threshold value used in searching for the first position and the second position, and to set the rotor position when the output signal exceeds the threshold value in the first search step and the second search step to the first position and the second position, respectively.

[0037] In addition, in the above aspect [1], the device may include a liquid feed pump and a liquid feed destination flow path that is a liquid feed destination of the liquid feed pump, the plurality of connection ports of the multiport valve may include a pump port to which the liquid feed pump is fluidly connected and a liquid feed destination port adjacent to the pump port to which the liquid feed destination flow path is fluidly connected, and the sensor may be a pressure sensor that detects a liquid feed pressure of the liquid feed pump. In this case, the control unit may be configured to, in the teaching, search for the first position of the rotor based on the output signal of the pressure sensor while operating the liquid feed pump to feed liquid, and to search for the second position of the rotor based on the output signal of the pressure sensor while operating the liquid feed pump to feed liquid, in the first searching step.

[0038] In addition, in aspect [2] of the above embodiment of the teaching device according to the present invention, the rotor is rotated by the small angle at a time, and the position at which the output signal of the sensor is maximum is set as the reference position of the rotor.

[0039] In the above aspect [2], the multiport valve may be provided with a pair of light-emitting elements and light-receiving elements, and may be configured such that when the rotor is at a position other than the reference position, light from the light-emitting elements toward the light-receiving elements is blocked, and when the rotor reaches the reference position, light from the light-emitting elements reaches the light-receiving elements. In this case, the control unit may be configured to, during the teaching, turn on the light-emitting elements and rotate the rotor by the small angle while reading the intensity of light from the light-emitting elements detected by the light-receiving elements, and set the position where the intensity of light from the light-emitting elements detected by the light-receiving elements is greatest as the reference position of the rotor.

[0040] In one embodiment of the teaching method of the present invention, a teaching method for setting a reference position of a rotor of a multi-port valve configured to switch the communication state between multiple connection ports for fluidly connecting piping as the rotor rotates includes providing a sensor whose output signal changes depending on the position of the rotor, rotating the rotor by small angle increments while reading the output signal of the sensor, and setting the reference position based on the value of the output signal of the sensor.

[0041] Aspect [1] of the above embodiment of the teaching method of the present invention includes: a first search step of rotating the rotor in one direction by small angle increments and searching for a first position of the rotor where the liquid delivery pressure changes based on the output signal of the pressure sensor; a second search step of rotating the rotor in another direction opposite to the one direction by small angle increments and searching for a second position of the rotor where the liquid delivery pressure changes based on the output signal of the pressure sensor; and a reference position setting step of setting an intermediate position between the first position searched for in the first search step and the second position searched for in the second search step as the reference position of the rotor.

[0042] In the above aspect [1], in the first search step and the second search step, the position of the rotor when the liquid delivery pressure when the liquid delivery pump delivers liquid at a predetermined flow rate exceeds a predetermined threshold value can be set to the first position and the second position, respectively.

[0043] In the above aspect [1], the plurality of connection ports of the multiport valve may include a pump port to which a liquid feed pump is fluidly connected and a liquid feed destination port adjacent to the pump port to which a liquid feed destination from the liquid feed pump is connected, and the sensor may be a pressure sensor that detects a liquid feed pressure of the liquid feed pump. In this case, the teaching method may include: in the first search step, searching for the first position of the rotor based on the output signal of the pressure sensor while the liquid feed pump is feeding liquid; and in the second search step, searching for the second position of the rotor based on the output signal of the pressure sensor while the liquid feed pump is feeding liquid.

[0044] In the aspect [2] of the teaching method according to the present invention, the rotor is rotated by the small angle at a time, and the position at which the output signal of the sensor is maximized is set as the reference position of the rotor.

[0045] In the above aspect [2], a pair of light-emitting elements and light-receiving elements can be attached to the multiport valve, and when the rotor is in a position other than the reference position, light from the light-emitting elements toward the light-receiving elements can be blocked, and when the rotor reaches the reference position, light from the light-emitting elements can reach the light-receiving elements. In this case, the light-emitting elements can be turned on and the rotor can be rotated by the small angle while reading the intensity of the light from the light-emitting elements detected by the light-receiving elements, and the position at which the intensity of the light from the light-emitting elements detected by the light-receiving elements is greatest can be set as the reference position of the rotor.

[0046] 2 Multiport valve 2a Valve head 2b Valve body 4 Liquid sending flow path 6 Liquid sending pump 8 Pressure sensor 10 Liquid sending destination flow path 12 Control unit 14 Connection port 14a Pump port 14b Liquid sending destination port 15 Port hole 16 Rotor 18 Groove 20 Through hole 21 Rotor shaft 22 Stator 24 Notch 26 Sensor holder 28 Light emitting element 30 Light receiving element

Claims

1. A teaching device for setting a reference position of a rotor of a multi-port valve configured to switch a communication state between a plurality of connection ports for fluidly connecting pipes as the rotor rotates, the teaching device comprising: the multi-port valve; a control unit configured to control an operation of the multi-port valve; and a sensor provided such that an output signal changes according to a position of the rotor of the multi-port valve, wherein the control unit is configured to rotate the rotor by a small angle while reading the output signal of the sensor and set the reference position based on a value of the output signal of the sensor in teaching for setting the reference position of the rotor.

2. The control unit is configured to execute: a first search step of rotating the rotor in one direction by a small angle and searching for a first position of the rotor at which the output signal of the sensor changes; a second search step of rotating the rotor in the other direction opposite to the one direction by a small angle and searching for a second position of the rotor at which the output signal of the sensor changes; and a reference position setting step of setting an intermediate position between the first position searched in the first search step and the second position searched in the second search step as the reference position of the rotor. The teaching device according to claim 1.

3. The control unit holds a threshold value used for searching for the first position and the second position, and in the first search step and the second search step, is configured to set the positions of the rotor when the output signal exceeds the threshold value as the first position and the second position, respectively. The teaching device according to claim 2.

4. A liquid delivery pump and a liquid delivery destination flow path which is the liquid delivery destination of the liquid delivery pump are provided. Among the plurality of connection ports of the multi-port valve, a pump port to which the liquid delivery pump is fluid-connected and a liquid delivery destination port adjacent to the pump port to which the liquid delivery destination flow path is fluid-connected are included. The sensor is a pressure sensor that detects the liquid delivery pressure of the liquid delivery pump. The control unit, in the teaching, in the first search step, while delivering liquid with the liquid delivery pump, searches for the first position of the rotor based on the output signal of the pressure sensor. In the second search step, while delivering liquid with the liquid delivery pump, it is configured to search for the second position of the rotor based on the output signal of the pressure sensor. The teaching device according to claim 2 or 3.

5. The teaching device according to claim 1, wherein the rotor is rotated by the minute angle, and a position where the output signal of the sensor becomes maximum is set as the reference position of the rotor.

6. The multi-port valve is provided with a light-emitting element and a light-receiving element that are paired with each other. When the rotor is in a position other than the reference position, light traveling from the light-emitting element to the light-receiving element is blocked. When the rotor reaches the reference position, light from the light-emitting element reaches the light-receiving element. The control unit, in the teaching, while rotating the rotor by the minute angle while lighting the light-emitting element and reading the intensity of the light from the light-emitting element detected by the light-receiving element, is configured to set a position where the intensity of the light from the light-emitting element detected by the light-receiving element becomes maximum as the reference position of the rotor. The teaching device according to claim 5.

7. A teaching method for setting a reference position of a rotor of a multi-port valve configured to switch a communication state between a plurality of connection ports for fluid-connecting pipes as the rotor rotates. A sensor is provided such that an output signal changes according to the position of the rotor. The rotor is rotated by a minute angle while reading the output signal of the sensor, and the reference position is set based on the value of the output signal of the sensor. Teaching method.

8. A first search step of rotating the rotor by a small angle in one direction and searching for a first position of the rotor at which the liquid feed pressure changes based on the output signal of the pressure sensor; a second search step of rotating the rotor by a small angle in the other direction opposite to the one direction and searching for a second position of the rotor at which the liquid feed pressure changes based on the output signal of the pressure sensor; and a reference position setting step of setting an intermediate position between the first position searched in the first search step and the second position searched in the second search step as the reference position of the rotor. The teaching method according to claim 7 includes these steps.

9. In the first search step and the second search step, when the liquid feed pressure when the liquid is fed at a predetermined flow rate by the liquid feed pump exceeds a preset threshold value, the positions of the rotor at that time are set as the first position and the second position, respectively. The teaching method according to claim 8 includes this.

10. The plurality of connection ports of the multi-port valve include a pump port to which a liquid feed pump is fluidly connected, and a liquid feed destination port adjacent to the pump port to which the liquid feed destination from the liquid feed pump is connected. The sensor is a pressure sensor for detecting the liquid feed pressure of the liquid feed pump. The teaching method includes, in the first search step, searching for the first position of the rotor based on the output signal of the pressure sensor while feeding the liquid by the liquid feed pump; and in the second search step, searching for the second position of the rotor based on the output signal of the pressure sensor while feeding the liquid by the liquid feed pump. The teaching method according to claim 8 or 9 includes these steps.

11. Rotating the rotor by the small angle, and setting the position at which the output signal of the sensor becomes maximum as the reference position of the rotor. The teaching method according to claim 7 includes this.

12. A teaching method according to claim 11, wherein a light emitting element and a light receiving element which are paired with each other are attached to the multi-port valve, and when the rotor is at a position other than the reference position, light traveling from the light emitting element to the light receiving element is blocked, and when the rotor reaches the reference position, light from the light emitting element reaches the light receiving element. The rotor is rotated by the minute angle while reading the intensity of the light from the light emitting element detected by the light receiving element with the light emitting element turned on, and the position at which the intensity of the light from the light emitting element detected by the light receiving element becomes maximum is set as the reference position of the rotor.

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