JP2015123447A - Centrifugal machine and centrifugal machine control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a centrifugal machine capable of accurately applying a desired g sec value to a sample, and ensuring short processing time.SOLUTION: A control unit determines a corresponding deceleration gradient (rotation speed drop rate) while referring to data stored in a storage unit on the basis of the type of a rotor recognized in S1 and an acceleration gradient recognized in S3 (S6). The control unit calculates a g sec value during deceleration corresponding to the determined deceleration gradient (S7). If the g sec value to date is a value obtained by subtracting this calculated g sec value during the deceleration from a set g sec value (S8), the control unit stops a stabilized operation and start deceleration (S9).

Description

The present invention relates to a centrifuge that rotates a sample at a high speed, and a control method thereof.

  A centrifuge (centrifuge) is used to separate or analyze substances having different densities by centrifugal force during high-speed rotation. In the centrifuge, the rotation speed (rotation speed: rpm) of the motor is determined, and the sample rotates at this rotation speed for a predetermined time. When performing such operations, as an index indicating the degree of acceleration (centrifugal acceleration) applied to the sample, the time integral value (g · sec value or centrifugal acceleration integration) of the centrifugal acceleration g applied to the sample by the rotational motion. Value) must be managed. That is, in performing one centrifugation process, it is necessary to perform this process so that a desired g · sec value is obtained. Here, since the centrifugal acceleration g is proportional to the square of the rotational speed, the g · sec value when the rotational speed is kept constant is the square of the set rotational speed (settling rotational speed) and this rotational speed. It is determined by the product of the time the number is maintained (settling time). Therefore, the settling speed and the settling time can be determined from the desired g · sec value and this relationship.

  However, since the settling speed in the centrifuge is set at a high speed of, for example, several tens of thousands rpm, the time (acceleration time) until the settling speed is reached from the stationary state, or the stationary rotational speed is reached from the stationary speed. The time until (the deceleration time) is a length that cannot be ignored compared to the settling time. For this reason, in order to accurately obtain the g · sec value at the time of centrifugation, it is necessary to consider not only the settling time but also the g · sec value at the time of acceleration and deceleration. Alternatively, in order to perform processing for giving a predetermined g · sec value to the sample, it is necessary to determine the settling speed and the settling time in consideration of the g · sec value during acceleration / deceleration. In this case, the g · sec value given by the process can actually be controlled by the settling time. That is, if the g · sec value at the time of acceleration and the g · sec value at the time of deceleration are determined between the start and end of the settling operation, the settling is performed so that a desired g · sec value is given by this processing. Time (timing to end settling operation and start deceleration) can be determined.

  Here, in the centrifuge, a rotor that is rotated by a motor is provided in the rotor chamber, and a plurality of samples are mounted in the rotor. Further, the set rotational speed is set in advance by the operator before the work, and the rotational speed of the motor (rotor) is controlled to be this value. However, even if the settling rotational speed is the same, in general, the acceleration time, the deceleration time, or the degree of fluctuation of the rotational speed during acceleration and deceleration varies depending on the number of samples, weight, and the like. For example, when the total weight of the sample is heavy, the moment of inertia to be driven becomes large, so that the acceleration time and the deceleration time become long, and when the total weight of the sample is light, these times become short. The acceleration time is determined by the characteristics of the motor, etc., and the deceleration time is determined by the characteristics of the motor and braking system.There is a lower limit time determined by these characteristics, and the acceleration time and deceleration time are set to zero. It is actually difficult to get close. That is, it is difficult to control the acceleration time and the deceleration time as compared with the control of the settling speed and the settling time, and it is particularly difficult to control the acceleration time and the deceleration time to be shorter than these lower limit times. . For this reason, control of the processing time and the g · sec value in the centrifugal separation processing is usually performed only by setting the settling time.

  For this reason, conventionally, only the centrifugal acceleration g determined at the settling speed and the settling time are considered, and the g · sec value at the time of acceleration and deceleration is not considered, and is proportional to the square of the settling speed x the settling time. The g · sec value calculated as to be used was used. In this case, the g · sec value actually given to the sample was larger than the g · sec value thus calculated by the amount during acceleration / deceleration. This error was particularly large when the acceleration / deceleration time was increased because the total weight of the sample was increased.

  Further, the g · sec value at the time of acceleration can be accurately calculated immediately after the start of the settling operation from the actual acceleration time or the change in the number of revolutions actually measured until reaching the settling number of revolutions. Therefore, the g · sec value during acceleration is calculated immediately after the start of settling operation, and the g · sec value obtained by subtracting the calculated g · sec value during acceleration from the desired g · sec value is obtained during the settling operation. It is also possible to set a settling time. In this case, it is possible to perform a process of giving the sample a g · sec value closer to a desired value than in the above example. However, in this case as well, the g · sec value at the time of deceleration is not taken into consideration, and therefore, it has been impossible to accurately perform the process of giving the desired g · sec value to the sample.

  In order to improve this point, in Patent Document 1, the g · sec value at the time of deceleration is accurately determined by controlling the rotation at the time of deceleration, and the overall g is determined using the g · sec value at the time of deceleration.・ Techniques for managing sec values are described. Here, as described above, it is difficult to control the deceleration time to be shorter than the lower limit time. However, the control to increase the deceleration time can be compared by controlling the motor current and the braking system. Can be done easily. For this reason, in the technique described in Patent Document 1, when various samples are mounted on the rotor, the deceleration time when the deceleration time becomes the longest is set, and the actual deceleration time is the set deceleration time. Such control is performed during deceleration. For this reason, the g · sec value during deceleration is determined in advance. Further, the g · sec value at the time of acceleration is accurately determined by actual measurement as described above.

  For this reason, in the technique described in Patent Document 1, the g · sec value during acceleration and the g · sec value during deceleration are accurately determined at the start of settling operation, and the settling time can be determined accordingly. A desired g · sec value can be accurately given to the sample by a single centrifugation process.

JP 2002-66381 A

  While the desired g · sec value can be given to the sample by the technique described in Patent Document 1, the deceleration time is lengthened to determine the deceleration time (g · sec value during deceleration) as described above. Control is performed. For this reason, the problem that the processing time of the whole centrifugation process until it stops after rotating a rotor becomes long compared with the case where control of deceleration time is not performed occurred.

  That is, it has been difficult to obtain a centrifuge capable of accurately giving a desired g · sec value to a sample and having a short processing time.

  The present invention has been made in view of such problems, and an object thereof is to provide an invention that solves the above problems.

In order to solve the above problems, the present invention has the following configurations.
The centrifuge of the present invention is a centrifuge that performs a centrifugal separation process of applying a centrifugal acceleration to the sample by rotating a rotor that accommodates the sample, from the situation of an increase in rotational speed when accelerating the rotor, It has a control part which presumes the situation of deceleration of the rotation speed at the time of decelerating the rotor.
In the centrifuge of the present invention, the control unit controls a time integral value of the centrifugal acceleration applied to the sample during the centrifugation process using the estimated situation when the rotor is decelerated. It is characterized by that.
In the centrifuge of the present invention, during the period during which the centrifugal separation process is performed, the rotor is rotated before the settling operation period, during which the rotation speed of the rotor is maintained at a settling rotation speed set in advance. An acceleration period for accelerating from the stopped state to the settling rotational speed, and a deceleration period for decelerating the rotor from the settling rotational speed to stop after the settling operation period. Estimating the state of deceleration of the rotor during the deceleration period from the state of acceleration of the rotor during the acceleration period, and setting the settling operation period using the estimated state of deceleration of the rotor. .
The centrifuge of the present invention includes a storage unit that stores data indicating a relationship between an acceleration state of the rotor and a deceleration state of the rotor during a period in which the centrifugal separation process is performed, and the control The unit estimates the state of deceleration of the rotational speed when the rotor is decelerated based on the data.
The centrifuge of the present invention uses the rotor selected from a plurality of types, and the storage unit stores the data for each type.
In the centrifuge of the present invention, the rotor is provided with a rotor identifier corresponding to the type, and the control unit recognizes the type of the rotor based on the rotor identifier.
In the centrifuge of the present invention, the storage unit stores the data indicating a relationship between a rotation speed increase rate when the rotor is accelerated and a rotation speed decrease rate when the rotor is decelerated. .
The centrifuge control method of the present invention is a centrifuge control method for performing a centrifugal separation process in which a rotor for accommodating a sample is rotated and centrifugal acceleration is applied to the sample, and the rotational speed of the rotor is preset. From the state of acceleration when accelerating to a predetermined rotational speed, the state of deceleration when the rotational speed of the rotor is decelerated from a preset rotational speed is estimated, and the estimated state of deceleration of the rotor is determined. And controlling the processing time in the centrifugation treatment.

  Since the present invention is configured as described above, a centrifuge capable of accurately giving a desired g · sec value to a sample and having a short processing time can be obtained.

It is a figure which shows typically the structure of the centrifuge used as embodiment of this invention. It is a figure which shows typically the time-dependent change of the rotational speed in a centrifugation process, and a centrifugal acceleration. It is a figure which shows the difference of g * sec value recognized in the centrifuge (c) used as prior art (a) (b) and embodiment of this invention. It is a figure which shows the time-dependent change of the centrifugal acceleration in the technique (a) of patent document 1, and the centrifuge (b) used as embodiment of this invention. It is a flowchart which shows the control method performed in the centrifuge used as embodiment of this invention.

  A centrifuge according to an embodiment of the present invention will be described. In this centrifuge, the g · sec value during acceleration (time integral value of centrifugal acceleration) is actually measured and the g · sec value during deceleration is also accurately calculated, but control for increasing the deceleration time is not performed. For this reason, a desired g · sec value can be accurately given to the sample, and the processing time can be shortened.

  FIG. 1 is a diagram showing a configuration of a centrifuge according to an embodiment of the present invention. In the centrifuge 10, the rotor 12 that is rotated by the drive motor 11 is mounted on the rotation shaft 111 of the drive motor 11 in the rotor chamber 13. A plurality of sample insertion holes (not shown) are provided around the rotation axis of the rotor 12, and the rotor 12 rotates at a high speed with a sample (not shown) fixed therein. The rotor chamber 13 is sealed with a lid 14 that can be opened and closed on the upper side closed.

  The rotor 12 is used by being selected from a plurality of types. The shape of the rotor 12 differs depending on the type. For this reason, even if it is set as the same rotation speed, the centrifugal acceleration applied to a sample differs according to this kind. For this reason, in order to accurately manage the g · sec value, it is necessary to recognize the type of the rotor 12 used. Also, the weight or moment of inertia of the rotor 12 varies depending on the type. For this reason, the acceleration time and the deceleration time also depend on the type of the rotor 12. For this reason, the rotor 12 is provided with a rotor identifier 121, and a rotor identification sensor 15 that can read the rotor identifier 121 is provided at a location corresponding to the rotor identifier 121 in the rotor chamber 13. The drive motor 11 is provided with a rotation speed sensor 16 that detects the rotation speed (rotation speed: rpm) of the rotation shaft 111 (rotor 12). Note that the centrifuge 10 may be configured to keep the rotor 12 (sample) at a preset temperature.

  The combination of the rotor identifier and the sensor is already a known technique, and the arrangement of the recesses (holes) formed in the rotor 12 is detected by an eddy current sensor (distance sensor), and the type of the rotor is determined from this arrangement pattern. And a method of detecting the arrangement of magnets with a magnet sensor for detecting a magnet such as a magnet and a Hall element or a magnetoresistive element, and discriminating the type from the arrangement pattern. As another rotor identification method, a centrifuge may be provided with a camera, and the type of rotor may be identified by an image taken by the camera.

  The control of the rotational speed (the number of rotations) of the drive motor 11 is performed by the control unit 20 controlling the current that drives the drive motor 11. The control unit 20 receives the output of the rotational speed sensor 16 (actually measured rotational speed) and feeds back this to control the rotational speed to a desired value. Moreover, the control part 20 also performs control other than the drive motor 11, for example, temperature control of the rotor 12, as control of this centrifuge 10 whole. Input and display of parameters relating to these controls can be performed by the display / operation unit 21 configured by a liquid crystal panel. The operator can also input from the display / operation unit 21 a desired g · sec value to be given to the sample in one centrifugation process (acceleration-settling operation-deceleration).

  The storage unit 22 stores various data for operating the centrifuge 10, and refers to this data when the control unit 20 controls the drive motor 11 and the like. The storage unit 22 is configured by a nonvolatile memory or ROM that maintains stored data even when the power is turned off. The output of the rotor identification sensor 15 is also input to the control unit 20, and the control unit 20 can recognize the type of the rotor 12 after the rotor 12 is mounted on the rotating shaft 111 and perform the above control. However, the type of the rotor 12 can be set to be input by the operator from the display / operation unit 21.

  Here, in order to shorten the processing time of the entire centrifugal separation process, it is preferable that the time (acceleration time) until the rotor 12 of the centrifuge 10 reaches a settling rotational speed (settling rotational speed) from a stationary state is short. . However, this acceleration time depends on the power performance of the drive motor 11, the moment of inertia of the rotor 12, the weight of the sample, etc., and it is impossible in practice to make the acceleration time zero. When the rotor 12 is decelerated from the set rotational speed to a stationary state, a mechanism for braking the rotational motion is used. The deceleration time at this time also depends on the inertia moment of the rotor 12, the weight of the sample, and the like. Both the acceleration time and the deceleration time become longer when the moment of inertia of the rotor 12 and the weight of the sample are large, and become shorter when these are small.

  Here, the weight of the sample can take an arbitrary value within a predetermined range, while the rotor 12 is selected from a plurality of types. For this reason, the dependence of acceleration time and deceleration time on the total weight of the sample can be considered for each type of rotor 12. That is, when the type of the rotor 12 is determined, it can be considered that there is a certain relationship between the total weight of the sample and the acceleration time, and between the total weight of the sample and the deceleration time. Therefore, when the type of the rotor 12 is determined, it can be considered that there is a certain relationship between the acceleration time and the deceleration time. This relationship can be obtained by calculation or an experiment performed in advance. For this reason, this relationship can be stored in advance in the storage unit 22 as a parameter in a table or approximate expression.

  Further, the acceleration time or the degree of increase in the number of rotations during acceleration can be measured using the rotation speed sensor 16 as in the technique described in Patent Document 1. For this reason, the acceleration time is actually measured immediately after the start of the settling operation, and the deceleration time corresponding to the acceleration time can be estimated. If the storage unit 22 stores the relationship between the acceleration time and the deceleration time for each type of rotor 12 that may be used, the control unit 20 stores this data after recognizing the type of the rotor 12. By reading from 22, the deceleration time can be recognized from the acceleration time.

  On the other hand, the relationship between the centrifugal acceleration applied to the sample and the number of rotations varies depending on the type of the rotor 12, but this relationship and this relationship for each type of the rotor 12 can also be stored in the storage unit 22.

  For this reason, the control unit 20 recognizes the type after the rotor 12 is mounted, and reads the above relationship according to the type of the rotor 12 from the storage unit 22, so The g · sec value can be calculated and the g · sec value during deceleration can be estimated. For this reason, immediately after the start of the settling operation, the settling time can be determined so that a desired g · sec value is given to the sample before the rotor 12 stops. Thereby, a desired g · sec value can be accurately given to the sample.

  FIG. 2 shows changes with time in the number of rotations during the centrifugation process time in the whole centrifuge (lower stage) and changes with time in the acceleration applied to the sample (upper stage). Here, the rate of increase and the rate of decrease in the acceleration period (during acceleration) before the settling operation period in which the rotation number is kept constant and the deceleration period (during deceleration) after the settling operation period are constant, respectively. Assumes. For this reason, at the time of acceleration / deceleration, the change rate of the rotation speed is constant, and the change rate of the acceleration changes in a quadratic function. The g · sec value corresponds to the integrated value (area) of the graph of the change in acceleration with time (upper stage).

  When the g · sec value at the time of acceleration / deceleration is ignored in the prior art, only the area of the hatched portion shown in FIG. 3A is treated as the g · sec value at the time of processing and is considered at the time of acceleration. When the deceleration time is not taken into consideration, only the area of the hatched portion shown in FIG. 3B is treated as the g · sec value at the time of processing. On the other hand, in the centrifuge 10 described above, the area of all the regions indicated by hatching in FIG. 3C is treated as the g · sec value at the time of processing, and an accurate g · sec value is obtained. It is done.

  4A shows the change over time in centrifugal acceleration in the technique described in Patent Document 1, and FIG. 4B shows the change over time in centrifugal acceleration in the centrifuge 10 described above. As shown in FIG. 4 (a), in the technique described in Patent Document 1, in order to determine the deceleration time, although the profile at the time of deceleration can be set as indicated by the dotted line, The profile during deceleration as indicated by the solid line is used. On the other hand, in the above-described centrifuge 10, as shown in FIG. 4B, the profile at the time of deceleration can be as shown by the dotted line in FIG.

  That is, in the centrifuge 10 described above, unlike the technique described in Patent Document 1, since the g · sec value at the time of deceleration is determined without performing control that lengthens the deceleration time, the processing time is increased. There is no. For this reason, a desired g · sec value can be accurately given to the sample, and the processing time can be shortened.

  FIG. 5 shows an operation (control method) of the control unit 20 after the rotor 12 is mounted in the centrifuge 10. Here, the g · sec value to be given in one process is input in advance by the operator operating the display / operation unit 21, and is recognized by the control unit 20.

  First, after attaching the sample to the rotor 12, the operator closes the lid 14 and seals the rotor chamber 12. Thereafter, when the operator presses a start SW (not shown), the control unit 20 drives the drive motor 11 to rotate the rotor 121. When the rotor 12 starts rotating, the controller 20 recognizes the type of the rotor 12 mounted on the rotating shaft 111 by the rotor identification sensor 15 (S1). The control unit 20 recognizes that the rotor 12 is used until the end of processing. Thereafter, the drive motor 11 rotates and acceleration to a preset settling speed starts (S2).

  Thereafter, the control unit 20 determines the current rotational speed of the drive motor 11 (rotor 12) and the acceleration gradient (the rate of increase of the rotational speed: the slope during acceleration in the lower part of FIG. 2) from the change in the output of the rotational speed sensor 16. Recognize (S3).

  Thereafter, when the rotational speed reaches the settling rotational speed (S4), the settling operation is started (S5). That is, the control unit controls the drive motor 11 so that the rotation speed is maintained. However, at this time, the settling time (time until deceleration is started) is not yet determined. The g · sec value only during the settling operation period can be recognized based on the type of the rotor 12 recognized in S1, the settling rotation speed, and the elapsed time from the start of the settling operation. Further, since the g · sec value at the time of acceleration can be calculated from the acceleration gradient recognized at S3 and the type of the rotor 12 recognized at S1, the control unit 20 is able to calculate from the start of processing (S2) to the current time. Can be recognized.

  Next, the control unit 20 refers to the data stored in the storage unit 22 based on the type of the rotor 12 recognized in S1 and the acceleration gradient recognized in S3, and the corresponding deceleration gradient (rotation during deceleration). A speed decrease rate is obtained (S6). Here, it is assumed that the storage unit 22 stores this data as a table.

  When the deceleration gradient is determined, the control unit 20 calculates a g · sec value during deceleration corresponding to the deceleration gradient (S7).

  As described above, the control unit 20 can recognize the g · sec value from the start of processing (S2) to the current time. When the g · sec value up to the present time becomes a value obtained by subtracting the calculated g · sec value during deceleration (S8) from the set g · sec value, the settling operation is terminated and deceleration is performed. Start (S9). Thereafter, after the deceleration is performed at the deceleration gradient estimated in S6, the rotation of the rotor 12 is stopped. The deceleration gradient at this time is equal to the deceleration gradient calculated in S7 if the data stored in the storage unit 22 is appropriate.

  Thereafter, the operator can open the lid 14 and take out the sample from the rotor 12. At this time, the g · sec value given to the sample is a desired value.

  In the above example, the acceleration gradient and the deceleration gradient are assumed to be constant. Even when these are not constant, the same control can be performed if the storage unit 22 stores data corresponding thereto. . In other words, when it is possible to estimate the state of decrease in the number of revolutions during deceleration from the state of increase in the number of revolutions during acceleration, the same control can be performed, and the corresponding g · sec value during deceleration is calculated. It is clear that you can do that.

  In the above example, the rotor 12 is selected and used from a plurality of types. However, even when only one type of rotor is used in a single centrifuge, data corresponding to this one type is used. Is stored in the storage unit 22, and the same control can be performed.

  In the above example, the rotor chamber 12 is depressurized (evacuated), but the same control can be performed even in a centrifuge having a low settling speed that does not require depressurization. it is obvious.

  Further, in the above example, the settling operation period, the acceleration period, and the deceleration period are provided in the centrifugal separation period, but in other operation modes as long as the rotor is accelerated and decelerated, The deceleration state can be estimated from the acceleration state, and the estimated deceleration state can be used for the operation (control) performed after the acceleration of the rotor is completed. For example, the time for ending the settling operation can be displayed on the display / operation unit in order to give a desired g · sec value to the sample without performing the control to end the settling operation. Furthermore, in the above centrifuge, the g · sec value was used as the management index for the centrifugation process. However, even when other indices are used, the predicted deceleration situation can be used in advance during the centrifugation process. Then, it is clear that the above configuration is effective.

10 Centrifuge (centrifuge)
DESCRIPTION OF SYMBOLS 11 Drive motor 12 Rotor 13 Rotor chamber 14 Cover 15 Rotor identification sensor 16 Rotational speed sensor 20 Control part 21 Display / operation part 22 Storage part 111 Rotating shaft 121 Rotor identifier

Claims (8)

A centrifuge that performs a centrifugal separation process of applying a centrifugal acceleration to the sample by rotating a rotor that accommodates the sample,
A centrifuge comprising a control unit that estimates a state of deceleration of the rotational speed when the rotor is decelerated from a state of increase of the rotational speed when the rotor is accelerated.   The control unit controls a time integral value of the centrifugal acceleration applied to the sample during the centrifugal separation process using the estimated situation when the rotor is decelerated. The centrifuge according to 1. During the period in which the centrifugal separation process is performed, the settling operation period in which the rotation speed of the rotor is maintained at a preset settling rotation speed and the settling from the state in which the rotor is stopped before the settling operation period An acceleration period for accelerating to a rotational speed, and a deceleration period for decelerating the rotor until it stops from the settling rotational speed after the settling operation period,
The controller is
Estimating the state of deceleration of the rotor during the deceleration period from the state of acceleration of the rotor during the acceleration period, and setting the settling operation period using the estimated state of deceleration of the rotor. The centrifuge according to claim 2. A storage unit for storing data indicating a relationship between the state of acceleration of the rotor and the state of deceleration of the rotor;
The centrifuge according to any one of claims 1 to 3, wherein the control unit estimates a state of reduction in rotational speed when the rotor is decelerated based on the data.   The centrifuge according to claim 4, wherein the rotor selected from a plurality of types is used, and the storage unit stores the data for each type. The rotor is provided with a rotor identifier corresponding to the type,
The centrifuge according to claim 5, wherein the control unit recognizes a type of the rotor based on the rotor identifier.   The said memory | storage part memorize | stores the said data which show the relationship between the rotational speed increase rate at the time of the acceleration of the said rotor, and the rotational speed decrease rate at the time of the deceleration of the said rotor. The centrifuge according to any one of the above. A method of controlling a centrifuge that performs a centrifugal separation process in which a rotor that houses a sample is rotated to apply centrifugal acceleration to the sample,
Estimating a deceleration situation when the rotational speed of the rotor is decelerated from a preset rotational speed from an acceleration situation when the rotational speed of the rotor is accelerated to a preset rotational speed, and the estimation A control method for the centrifuge, wherein the processing time in the centrifugal separation process is controlled using the reduced speed of the rotor.

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