Centrifugal machine

Abstract

To provide a centrifugal machine simply configured and capable of achieving adjustment of the stop position of a centrifugal rotor within a short time.SOLUTION: A centrifugal machine 1 comprises: a centrifugal rotor 2 in which a plurality of sample tube holes 4 for storing sample tubes 20 carrying samples are arranged at equal intervals on a circumference about a rotary shaft 3; a motor that rotary-drives the centrifugal rotor 2; and a control unit 6 that controls rotary-driving of the motor. The motor is a positionable motor that can rotate for sample centrifugal separation, and the rotary shaft of the motor can be moved to and stopped at a prescribed angle position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a centrifuge, and more particularly to a centrifuge in which the positioning of the centrifuge rotor is performed when the centrifuge is stopped. [Background technology]

[0002] Patent document 1 discloses a centrifuge that transmits the rotation of a motor to a centrifugal rotor and rotates sample containers inserted into container support holes drilled in the centrifugal rotor, and turns the motor on and off by opening and closing a cap.

[0003] Patent Document 2 discloses a technology for stopping and holding a centrifugal rotor at an arbitrary set position in order to automatically attach and detach a sample container to be centrifuged. The technology involves providing an auxiliary motor consisting of a step motor in addition to the main motor that rotates the centrifugal rotor, and connecting the two with a clutch mechanism.

[0004] Patent Document 3 discloses a centrifuge equipped with a centrifugal motor directly connected to a centrifugal rotor that suspends packets containing samples, and a positioning motor for positioning the centrifugal rotor via a connecting means that can be connected and disconnected to the centrifugal motor. In other words, it is proposed to provide a centrifugal motor directly connected to the centrifugal rotor and a positioning motor that positions the centrifugal rotor independently.

[0005] In paragraph

[0003] of Patent Document 4, it is described as prior art that "a servo motor for positioning the centrifuge rotor is used to position the centrifuge rotor, separate from the drive motor for high-speed rotation of the centrifuge rotor," and in the claims it is proposed to provide a positioning means, separate from the drive motor that rotates at high speed, that directly detects the position of the centrifuge rotor and moves the centrifuge rotor to the position for loading or unloading a sample container.

[0006] Patent Document 5 discloses that an angle sensor is attached to a motor. Non-Patent Document 1 discloses a technique for calculating the coordinates of rotation of a motor shaft. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Utility Model Application Publication No. 64-1746 [Patent Document 2] Japanese Utility Model Application Publication No. 55-53562 [Patent Document 3] Japanese Patent Application Publication No. 6-170281 [Patent Document 4] Japanese Patent Application Laid-Open No. 2000-176316 [Patent Document 5] Japanese Patent Application Laid-Open No. 2013-19785 [Non-patent literature]

[0008] [Non-Patent Document 1] ORIENTAL MOTOR CO.,LTD PENGA No.179 (2014) P18-P21 "Development of a battery-free multi-rotation absolute sensor" by Tokuyuki Negishi Summary of the Invention [Problem to be solved by the invention]

[0009] In the operation of a centrifuge, a plurality of sample tubes containing samples are typically loaded into the sample tube holes in the centrifuge rotor so that the weight distribution is as uniform as possible, and the centrifuge rotor rotates at high speed to perform centrifugation. When the centrifugation operation is complete, the centrifuge rotor is stopped, and the plurality of sample tubes containing the samples are sequentially removed from the centrifuge rotor and sent to the subsequent processing stage. Here, each sample is usually not identical, and various data are associated with each sample. These various data are organized as sample numbers, etc., and assigned as tube numbers to each sample tube. The sample tubes are then sent to the subsequent processing stage together with this information.

[0010] For this reason, it is preferable to place samples with data numbers No. 1, No. 2, No. 3, etc., in sample tubes No. 1, No. 2, No. 3, etc., respectively, and then load these sample tubes into the sample tube holes No. 1, No. 2, No. 3, etc. of the centrifuge rotor. Centrifugation is performed, and the sample tubes are removed in the order of No. 1, No. 2, No. 3, etc., and sent to the subsequent stage in that order to prevent sample mixing errors.

[0011] In such cases, after the centrifugation operation is complete, the sample tube labeled No. 1 is first found, removed from the centrifuge rotor, and sent to the next stage. Next, the centrifuge rotor is slightly rotated by hand, and the sample tube labeled No. 2 is removed in the same manner and sent to the next stage. This procedure was performed sequentially, but it was problematic in terms of work efficiency.

[0012] To eliminate this inconvenience, the above-mentioned Patent Documents 2 to 4 disclose a technique in which the centrifuge motor is stopped once the centrifugation operation is completed, and then a position adjustment motor, such as a step motor, provided separately from the centrifugation motor is used to stop the centrifuge rotor at a specific position. By employing such a centrifuge, it becomes possible to always stop a sample tube labeled No. 1 at the front, and then rotate the centrifuge rotor little by little to remove the sample tubes in order of their label numbers and send them to the subsequent stage.

[0013] However, in the case of a device that uses the above-mentioned method of stopping the centrifuge motor and then driving a separately provided position adjustment motor that changes the angular position of the centrifuge rotor to adjust the angular position, there are problems in that the structure becomes complicated and it takes time to adjust the position of the centrifuge rotor.

[0014] On the other hand, in recent years, there has been a demand for centrifuges to be used in automated systems that automatically centrifuge large volumes of samples and automatically send the processed samples to subsequent processing stages, rather than operating them manually. When using a centrifuge in such a system, the centrifuge is operated by a robot.

[0015] When a centrifuge is used in an automated system, a robot is used to remove the sample tube containing the centrifuged sample and automatically send it to the subsequent processing stage. This means that when the centrifugation operation is completed, it is necessary for the specific sample tube to be in a predetermined position. This has led to an increasing demand for a centrifuge in which the centrifuge rotor stops in a fixed position, and furthermore, from the perspective of increasing the speed of automated systems, a centrifuge in which the stopping position of the centrifuge rotor can be adjusted in a short time.

[0016] The present invention has been made in consideration of the above-described background art and the problems associated with the background art, and an object of the present invention is to provide a centrifuge that has a simple configuration and that allows the stop position of the centrifugal rotor to be adjusted in a short time. [Means for solving the problem]

[0017] In order to achieve the above object, the present invention provides a centrifuge as described in the following [1] to [4]. [1] A centrifuge comprising a centrifugal rotor in which a plurality of sample tube holes for accommodating sample tubes containing samples are arranged at equal intervals on a circumference centered on a rotation axis, a motor that drives the rotation of the centrifugal rotor, and a control unit that controls the rotation of the motor, characterized in that the motor is a positionable motor that can rotate for centrifugal separation of samples and can move and stop the rotation axis of the motor to a predetermined angular position. [2] The centrifuge described in [1] above, characterized in that the control unit stores a rotation program that sets the rotation for centrifugal separation of the sample over time, a stop program that stops the centrifugal rotor at a predetermined stop angle position, and a movement program that moves the centrifugal rotor from a predetermined stop angle position to another predetermined stop angle position. [3] The centrifuge according to [2] above, characterized in that when the centrifugation process is completed under the set conditions by the rotation program of the control unit, the control unit shifts to the stop program, enters a deceleration process to slow down the rotation of the rotating shaft, terminates the deceleration process when the rotation speed reaches a predetermined low speed, and stops the rotating shaft of the motor at a set stop angle position based on the absolute angular position of the motor and the set stop angle position. [4] The centrifuge described in [2] above, characterized in that a fixed position feed signal input unit is provided to move the stop position of the centrifugal rotor, and when a signal from the fixed position feed signal input unit is sent to the control unit, the control unit uses a movement program to move the centrifugal rotor to another stop position that is a predetermined angle away from the current stop position. [Effects of the Invention]

[0018] The centrifuge according to the present invention described above has a simple configuration and is capable of adjusting the stop position of the centrifugal rotor in a short time. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a conceptual perspective view of a centrifuge according to a preferred embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a schematic cross-sectional view of the centrifuge of FIG. 1. [Figure 3] FIG. 2 is an explanatory diagram of a control unit of the centrifuge of the present invention. [Figure 4] FIG. 1 is a flow chart showing the process from the end of centrifugation to stopping at a fixed position in a conventional technology (a centrifuge provided with an auxiliary motor for position adjustment in addition to the main motor for centrifugation), and FIG. 2 is a flow chart showing the process from the end of centrifugation to stopping at a fixed position in a centrifuge according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a centrifugal separator according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual perspective view of a centrifuge according to a preferred embodiment of the present invention, and FIG. 2 is a conceptual cross-sectional view thereof. In the centrifuge 1 according to this embodiment, sample tube holes 4 (4a to 4f) for accommodating sample tubes 20 (20a to 20f) containing samples are provided at six locations on the top surface of the centrifugal rotor 2, spaced at equal intervals around the circumference of the rotation axis 3 of the centrifugal rotor 2. In this embodiment, six sample tube holes 4a to 4f are provided at equal intervals on the top surface of the centrifugal rotor 2, but naturally, the number of sample tube holes 4 is not limited to six, and the number can be increased or decreased depending on the size of the centrifugal rotor 2, the size of the sample tubes 20, etc.

[0021] The centrifugal rotor 2 is rotated by a positionable motor 5 that is directly coupled to the rotation shaft 3 of the centrifugal rotor 2 and that can rotate for centrifugation and move and stop the rotation shaft 3 to a predetermined angular position. In this preferred embodiment, a stepping motor is used as the positionable motor 5.

[0022] The following description will be made mainly on an example in which a stepping motor is used as the positionable motor 5, but as will be described later, a servo motor or the like can also be used. In this embodiment, the stepping motor 5 and the rotation shaft 3 of the centrifugal rotor 2 are directly connected. Therefore, stopping the rotation position of the stepping motor 5, which is a positionable motor, at a predetermined position is equivalent to stopping the centrifugal rotor 2 at a predetermined position. However, it is also possible to interpose a transmission between them. In this case, too, the rotation position of the stepping motor 5 and the rotation position of the centrifugal rotor 2 correspond one-to-one, so stopping the rotation position of the stepping motor 5 at a predetermined position is equivalent to stopping the centrifugal rotor 2 at a predetermined position.

[0023] The start of rotation of the stepping motor 5, changes in rotation speed, stopping, movement of the stopping position, and other processes are carried out by signals from the control unit 6. At least a rotation program 6a, a stopping program 6b, and a movement program 6c are recorded in the control unit 6. The control unit 6 can be realized by, for example, a control PLC (Programmable Logic Controller).

[0024] The centrifugal rotor 2 is covered with an openable and closable lid 7. Closing the lid 7 closes the chamber, which is the space in which the centrifugal rotor 2 rotates, preventing the sample from scattering or the like. In addition, a lid open / closed detection means 8 for detecting whether the lid 7 is open or closed is provided on the lid 7 itself or on the centrifuge main body 9, and a signal 8a detected by the lid open / closed detection means 8 is sent to the control unit 6.

[0025] Furthermore, a fixed position feed signal input unit 10 is provided at an appropriate position on the centrifuge body 9, and a signal 10a from the fixed position feed signal input unit 10 is sent to the control unit 6. The fixed position feed signal input unit 10 can be realized as a push button switch or the like.

[0026] Next, the operation of the centrifuge 1 shown in FIGS. 1 and 2 will be described with reference to the explanatory diagram of FIG.

[0027] With the lid 7 open, there is a location where the sample tube 20 can be easily inserted into and removed from the centrifuge rotor 2. In the present invention, this location is referred to as the sample tube insertion location A. The sample tube insertion location A can be set arbitrarily, taking into consideration the configuration of the centrifuge and the entire system. For example, taking into consideration the ease of inserting the sample tube 20 into the sample tube hole 4 provided in the centrifuge rotor 2, the innermost location of the centrifuge rotor 2, in other words, the location of the centrifuge rotor 3 closest to the hinge 11 connecting the lid 7 and the centrifuge main body 9, can be set as the sample tube insertion location A (see Figures 1 and 2).

[0028] First, the first sample tube hole 4a of the centrifuge rotor 2 is moved to the sample tube mounting position A, and the first sample tube 20a containing a sample is loaded into the first sample tube hole 4a. Then, the centrifuge rotor 2 is rotated slightly to move the second sample tube hole 4b to the sample tube mounting position A, and the second sample tube 20b is mounted in the second sample tube hole 4b. This process is repeated until the six sample tubes 20a-20f are sequentially loaded into the sample tube holes 4a-4f at the sample tube mounting position A. This operation can be performed manually or automatically using a robot. In the case of automatic operation, the movement of the centrifuge rotor 2 can also be performed using a fixed position feed signal input unit 10 and a movement program 6c recorded in the control unit 6, which will be described later.

[0029] Subsequently, when the lid 7 is closed manually or by a robot, the lid open / close detection means 8 detects that the lid 7 is closed and sends a signal 8a to the control unit 6. Upon receiving this signal 8a, the control unit 6 starts the centrifugation operation. In other words, the signal 8a that detects that the lid 7 is closed serves as a centrifugation start signal.

[0030] When the control unit 6 receives the centrifugation start signal 8a, it rotates the stepping motor 5 based on the rotation program 6a recorded in the control unit 6, thereby centrifuging the sample. The rotation program 6a rotates the centrifuge rotor 2 at a preset rotation speed for a preset rotation time, thereby centrifuging the sample. The rotation program 6a is not limited to a program that simply rotates the centrifuge rotor 2 at a constant speed, but can also be a program that changes the rotation speed from moment to moment, which can be easily achieved using a rewritable memory such as RAM.

[0031] When the recorded rotation program 6a ends, the control unit 6 proceeds to the recorded stop program 6b without stopping the centrifugal rotor 2. The stop program 6b changes the stepping motor 5 from a high-speed rotation state to a set low-speed rotation state, and further stops the stepping motor 5, and consequently the centrifugal rotor 2, so that the first sample tube hole 4a stops at a set angular position, i.e., the sample tube loading position A, where the sample tube 20 can be easily loaded and unloaded.

[0032] Since the sample tube 20a labeled No. 1 first always stops at the sample tube loading position A where sample tubes can be easily handled, the sample tube 20a can be easily and correctly removed from the centrifuge rotor 2, for example, manually, without having to search for the specific sample tube 20a, and can be sent to the subsequent processing step. Also, for the same reason, the task of sending the centrifuged sample tube 20a to the subsequent processing step without mixing up the samples can be easily automated using a robot.

[0033] With the first sample tube hole 4a of the centrifuge rotor 2 stopped at the sample tube attachment position A, the first sample tube 20a is removed from the centrifuge rotor 2 and sent to the subsequent processing step, and then the fixed position feed signal input unit 10 is operated to send the signal 10a to the control unit 6. For example, if a push button switch is used as the fixed position feed signal input unit 10, the push button switch is pressed manually or by a robot to send the fixed position feed signal 10a to the control unit 6.

[0034] When a fixed position feed signal 10a is input to the control unit 6, the movement program 6c recorded in the control unit 6 starts, driving the stepping motor 5 to rotate the centrifugal rotor 2 by a set movement angle, for example, in the case of the centrifugal rotor 2 having six evenly spaced sample tube holes 4a to 4f as in this embodiment, the centrifugal rotor 2 is rotated by 60 degrees from its current stopping position, and the second sample tube hole 4b, which is loaded with the second sample tube 20b having the No. 2 information and label, is stopped at the sample tube attachment position A.

[0035] Then, at this location, the No. 2 sample tube 20b is removed from the centrifuge rotor 2 and sent to the subsequent processing step, and the fixed position feed signal input unit 10 is operated again, and this process is repeated. In this way, all sample tubes 20a-20f can be stopped in order at the sample tube attachment position A, removed, and sent to the subsequent processing step as a simple, error-free operation. As a result, it is possible to prevent operational errors when removing sample tubes and sending them to the subsequent processing step, and it is also easy to build an automatic system that automatically centrifuges large quantities of samples and automatically sends the processed products to the subsequent processing step in sequence.

[0036] Thereafter, for example, to centrifuge the next lot of samples, the fixed position feed signal input unit 10 is operated, or the control unit 6 is programmed to return the first sample tube hole 4a of the centrifuge rotor 2 to the sample tube attachment position A, and the first sample tube 20a of the next lot is again loaded into the first sample tube hole 4a. The fixed position feed signal input unit 10 is then operated, and the same process is repeated to load new sample tubes 20a-20f into all sample tube holes 4a-4f. Of course, the centrifuge according to the present invention can also be used in a variety of ways, such as loading new sample tubes of the next lot at the same position after each sample tube is removed, and then moving the centrifuge rotor a predetermined angle.

[0037] The centrifuge 1 according to the present invention can also be realized as an embedded centrifuge that is incorporated into a centrifuge operation system. In this case, for example, the centrifuge 1 is operated by a robot in the centrifuge operation system, and the lid 7 of the centrifuge 1 according to the present invention is closed by a robot hand, which is a robot, and the centrifugation process is carried out according to the rotation program 6a of the control unit 6. When the centrifugation process is completed, the sample tube 20a bearing the information No. 1, symbolized by the label No. 1, is automatically stopped at a predetermined position (sample tube loading position A) by the stop program 6b of the control unit 6.

[0038] The sample tube removal robot then removes the sample tube 20a from the specified position and sends it to the subsequent processing step. The system then sends a centrifuge rotor fixed position send signal 10a to the control unit 6, which then moves and stops the angular position of the centrifuge rotor 3 according to the control unit's movement program 6c. The sample tube 20b with the No. 2 information from the specified position is similarly removed and sent to the subsequent processing step, and this is repeated for all sample tubes 20a-20f. In a centrifuge operation system automated using a robot, the fixed position send signal input unit 10 can be provided on the system side, i.e., in a location other than the centrifuge, as described above, and the fixed position send signal 10a can be sent from the system side to the control unit 6.

[0039] As described above, the centrifuge 1 according to the present invention uses the stepping motor 5, which is a positionable motor that can rotate the centrifugal rotor 2 for centrifugal separation and can move and stop the rotation shaft of the motor to a predetermined angular position, as the motor that rotates the centrifugal rotor 2 for centrifugal separation. Therefore, the centrifuge 1 integrates two devices, namely, a main motor for conventional centrifugation and an auxiliary motor consisting of a step motor or the like for stopping the centrifugal rotor at a predetermined position, and does not require means for switching and connecting the main motor and auxiliary motor, resulting in a simple configuration. Furthermore, the centrifuge 1 according to the present invention does not require switching and connecting operations between the main motor and the auxiliary motor, and therefore can perform a fixed-position stopping operation after the deceleration operation of the centrifugal rotor 2 without stopping the centrifugal rotor 2, thereby shortening the time from the end of centrifugation to stopping at the fixed position.

[0040] Specifically, when using #1 [conventional flow] in Figure 4, the time required from #1-1 [end of centrifugation] to #1-3 [stop of rotor] was approximately 10 seconds in total, the time required from #1-3 [stop of rotor] to #1-5 [origin position detection operation] was approximately 10 seconds, and the time required from #1-5 [origin position detection operation] to #1-5 [fixed position stop operation] was approximately 10 seconds. In contrast, for a centrifuge of approximately the same size, when #2 [Flow of the present invention] in Figure 4 was used, the time required from #2-1 [End of centrifugation] to #2-3 [Completion of deceleration] was approximately 5 seconds in total, and the time required from #2-3 [Completion of deceleration] to #2-3 [Operation to stop at fixed position] was approximately 2 seconds. Thus, it was confirmed that the centrifuge according to the present invention can speed up the removal of sample tubes.

[0041] The stepping motor 5, which is the positionable motor, can also be realized by a servo motor, for example. In a stepping motor, the rotor rotates at a fixed angle by switching the phase through which current flows, allowing positioning without a sensor. On the other hand, a servo motor is equipped with a sensor that detects the rotation angle and speed, and controls the current to rotate the rotor according to the commanded position and speed.

[0042] The characteristics of stepping motors can be summarized as 1) open-loop control, 2) high torque at low to medium speeds, 3) positioning accuracy determined by the reference step angle, 4) high heat generation, etc. On the other hand, the characteristics of servo motors can be summarized as 1) closed-loop control, 2) high torque at medium to high speeds, 3) positioning accuracy dependent on sensor resolution, 4) low heat generation, etc. Depending on the specific requirements of the centrifuge, the optimum characteristics can be obtained by selecting one of the above features. For example, in a centrifuge used for "spin down" centrifugation, which does not require a high rotation speed, it is preferable to use a stepping motor, which provides high torque at low to medium speeds.

[0043] In addition, the stepping motor has a built-in absolute angle sensor directly connected to the rotation axis of the centrifugal rotor, so the reference point of the centrifugal rotor is determined when the stepping motor is fixed to the centrifuge body during the manufacturing stage of the centrifuge. When using a servo motor, an angle position marker is fixed to the outside of the motor for absolute angle detection, and the angular position of the rotor is recognized and controlled based on that. Therefore, the use of a stepping motor has the advantage of simplifying the structure of the centrifugal rotor.

[0044] Although the embodiments of the centrifuge according to the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and changes are possible within the scope of the centrifuge as the technical idea of ​​the present invention as set forth in the claims. [Industrial Applicability]

[0045] The centrifuge according to the present invention has a simple configuration and allows the adjustment of the stopping position of the centrifuge rotor in a short time, making it suitable for a wide range of applications, particularly as a centrifuge for performing operations such as "spin down" that do not require a particularly high rotation speed, and as a centrifuge incorporated into a centrifuge operation system constructed to centrifuge a large amount of sample. [Explanation of symbols]

[0046] 1. Centrifuge 2 Centrifugal rotor 3 Rotation Axis 4(4a, 4b, 4c, 4d, 4e, 4f) Sample tube holes 5 Positionable motor (stepping motor) 6 Control Unit 6a Rotation Program 6b Stop Program 6c Travel Program 7 Lid 8 Lid opening / closing detection means 8a Signal from lid opening / closing detection means 9 Centrifuge body 10 Fixed position feed signal input section 10a Signal from fixed position feed signal input section 11 Hinge 20(20a, 20b, 20c, 20d, 20e, 20f) Sample tube A Sample tube attachment point

Claims

1. A centrifuge comprising a centrifugal rotor in which a plurality of sample tube holes for accommodating sample tubes containing samples are arranged at equal intervals on a circumference centered on a rotation axis, a motor that drives the rotation of the centrifugal rotor, and a control unit that controls the rotation of the motor, characterized in that the motor is a positionable motor that can rotate for centrifugal separation of samples and can move and stop the rotation axis of the motor to a predetermined angular position.

2. 2. The centrifuge according to claim 1, wherein the control unit stores a rotation program that sets rotation over time for centrifugal separation of a sample, a stop program that stops the centrifuge rotor at a predetermined stop angle position, and a movement program that moves the centrifuge rotor from a predetermined stop angle position to another predetermined stop angle position.

3. 3. The centrifuge according to claim 2, wherein when the centrifugation process is completed under the set conditions by the rotation program of the control unit, the control unit shifts to the stop program and starts a deceleration process of decelerating the rotation of the rotating shaft, and when the rotation speed reaches a predetermined low speed, the deceleration process ends and the rotating shaft of the motor is stopped at a set stop angular position based on the absolute angular position of the motor and the set stop angular position.

4. 3. The centrifuge according to claim 2, further comprising a fixed position feed signal input unit for moving the stop position of the centrifugal rotor, wherein when a signal from the fixed position feed signal input unit is sent to the control unit, the control unit executes a movement program to move the centrifugal rotor to another stop position that is spaced a predetermined angle from the current stop position.

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