JP4347984B2 - centrifuge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a centrifuge that is used to separate various samples for each component, particularly to determine the type of a mounted rotor and to have a function of rotating the rotor by a control method suitable for the rotor, The present invention proposes a centrifuge having a function of detecting the rotational speed of the rotor using the rotor type discrimination function.
[0002]
[Prior art]
The centrifuge is a device for rotating various rotors loaded with a sample to be centrifuged at high speed, and is used in such a manner that the rotor is frequently replaced according to the purpose and used for the purpose of the experiment.
As a control method of the centrifuge, if the type of the rotor changes, it is necessary to perform control in accordance with driving conditions such as the maximum rotation speed, acceleration characteristics, and deceleration characteristics allowed for the rotor.
[0003]
For example, when a high-frequency induction motor is controlled by an inverter, if the acceleration characteristics and deceleration characteristics are not set according to the magnitude of the inertia of the rotor, which is the load, overcurrent will flow, leading to malfunctions that lead to inverter and motor failure. is there. If there is excessive imbalance in the rotor, it is necessary to stop the operation to prevent danger.
As described above, since various settings are required to start the centrifuge, there is a disadvantage that handling thereof is complicated. In particular, when many samples must be analyzed one after another, the laborious work is forced, and there is a disadvantage that the analysis work takes time.
[0004]
For this reason, the present applicant has proposed a centrifuge that automates these setting operations in Japanese Patent Laid-Open No. 6-198219 (Japanese Patent No. 2514554). In the previously proposed centrifuge, the specifications of each rotor are stored in advance in storage means such as ROM or RAM, and each rotor is equipped with a plurality of magnets representing the specifications of each rotor, and the number and arrangement of these magnets. By reading the pattern with a magnetic sensor provided on the fixed part, the storage means is accessed by the number of magnets read and the arrangement pattern, data representing the specifications of each rotor is read, and the read data is sent to the activation controller. By setting, it is configured to automatically perform various settings when the centrifuge is started.
[0005]
[Problems to be solved by the invention]
According to the above-described prior art, the rotor specifications are determined even when the rotor is stationary by simply mounting the rotor to the centrifuge, and various settings necessary at the time of start-up are automatically performed and the operation starts immediately. The advantage that the analysis work can be completed in a short time is obtained. However, on the other hand, since the number of magnets can be counted even when the rotor is stationary, the number of magnetic sensors to be mounted on the centrifuge is increased, resulting in an increase in cost.
[0006]
Further, in the conventional centrifuge, since the rotation speed (rotation speed) of the rotor is detected by a rotation detector using an optical sensor, the rotation detector also has a disadvantage that costs are increased.
A first object of the present invention is to provide a centrifugal separator that can be manufactured at a low cost by reducing the number of magnetic sensors and that can be started up in a short time.
[0007]
A second object of the present invention is to provide a centrifuge capable of achieving further cost reduction by utilizing a function for determining the type of rotor and utilizing it as a sensor for detecting the rotational speed of the rotor. It is something to try.
[0008]
[Means for Solving the Problems]
In the first aspect of the present invention, in the centrifuge in which a rotor having various specifications is detachably attached to the rotational drive shaft, and the rotational shaft drive characteristics are controlled according to the specification of the rotor.
The rotor is equipped with a plurality of magnets representing the specifications of each rotor along the circumference with the rotational drive shaft as the axis, and the fixed portion facing the magnet mounting surface corresponds to both ends of the magnet mounting angle range. Attach a magnetic sensor to each of the positions ,
[0009]
Magnetic sensor mounted on each of the positions corresponding to both ends of the angle range Mounting is a structure that utilizes the detected signal of the presence of a magnet at the same time during rotation of the rotor as a counting start signal and the terminal count signal of the magnet,
The angular range of the magnet to be attached to B over data suggest the centrifugal separator within 180 °.
[0010]
According to claim 2 of the present invention, the rotor is determined that in the state where the detection signal of Oite magnet centrifugal separator of claim 1 Symbol placement does not reach the number of reactions scheduled rotor is not mounted correctly in the drive shaft abnormality A centrifuge having a configuration provided with a judging means is proposed .
[0011]
According to claim 3 of the present invention proposes a configuration as the centrifugal separator for measuring the rotational speed of the rotor by a signal Oite magnetic sensor in claim 1 or 2 centrifugal separator according detects the presence of a magnet at the same time.
[0012]
[Action]
According to the configuration of the centrifuge according to the present invention, a plurality of magnets representing the specifications of each rotor are mounted on the rotor, but two magnetic sensors may be mounted on the fixed portion. As a result, the number of magnetic sensors is less than a fraction of that of the previously proposed centrifuge, and accordingly, the scale of the circuit that takes in the detection signals of the magnetic sensors can be reduced, so that cost reduction can be expected. .
[0013]
In the case where the mounting angle range of magnets within 180 ° can be obtained a signal to terminate the signal and count starts counting the number of magnets while the rotor is at least one revolution. As a result, it is possible to determine the rotor type and complete the setting of the rotation speed in a short time after the rotor is mounted .
[0014]
Further, according to the centrifugal separator proposed in claim 3 of the present invention, since the rotational speed of the rotor is detected using the magnet and the magnetic sensor for discriminating the type of the rotor, the rotation detector for detecting the rotational speed of the rotor. There is no need to provide another. Therefore, the advantage which can expect cost reduction also in this point is acquired.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows the configuration of the main part of a centrifuge according to the present invention. In FIG. 1, reference numeral 1 denotes a rotor chamber, 2 denotes a rotary shaft protruding at the axial center of the rotor chamber 1, 3 denotes a motor for driving the rotary shaft 2 to rotate, 4 denotes a rotor mounted on the rotary shaft 3, Reference numeral 5 denotes a fixed portion.
In the present invention, a magnet and a magnetic sensor are attached to the rotor 4 and the fixed portion 5. That is, the magnet M is attached to the rotor 4, and the magnetic sensor H is attached to the fixed portion 5.
[0016]
The rotor 4 is generally conical, and a magnet M is mounted on the bottom surface thereof. As shown in FIGS. 2 and 3, the magnet M is mounted in six combinations from a maximum of seven (M1 to M7) to two of M1 and M7 in this embodiment, and M1 and M7 as modifications. A total of seven types of arrangement patterns can be taken by adding a combination of other magnets excluding any one of the above. In the example shown in FIG. 2, the angle range of 180 ° is divided by 30 °, and magnets M1 to M7 are arranged every 30 °. In the example shown in FIG. 3, for example, a case is shown in which six magnets are removed from which the magnet M4 at the center position within a 30 ° angle pitch is removed. An example of the arrangement pattern of the magnets M is shown in FIG. If there are many types of rotors to be discriminated, the arrangement pitch of the magnets may be set to a 20 ° angle which is smaller than the 30 ° angle.
[0017]
As each specification of the rotor, the maximum rotation speed, the rotation radius, the centrifugal force, the acceleration characteristics, the deceleration characteristics, the imbalance sensitivity, the overspeed rotation speed, and the like can be considered.
A method for counting the number of magnets M will be described. When the magnet M is arranged in an angle range of 180 °, the magnetic sensor H1 and H2 are arranged on both ends of the angular range in which the magnet M is arranged on the fixed portion 5 so as to face the circumference where the magnet M is arranged. That is, as shown in FIGS. 2 and 3, the magnetic sensors H1 and H2 are arranged at 180 °.
[0018]
In the state shown in FIG. 2, the magnetic sensors H1 and H2 simultaneously detect the presence of the magnets M1 and M7. By using this detection state as a counting start signal, the magnetic sensor H1 detects the passage of the magnets M2, M3, M4, M5, and M6 while the rotor 4 makes a half-turn clockwise from that state. The presence of the five magnets M2 to M6 can be detected by counting the detection signals of the magnetic sensor H1. When the magnet M6 passes through the magnetic sensor H1 and the magnet M7 arrives at a position facing the magnetic sensor H1, the magnet M1 faces the magnetic sensor H2 at this time. Therefore, the magnets M1 and M7 are simultaneously facing the magnetic sensors H1 and H2. In this state, the end of counting of the magnet M and the start of counting are instructed to start the second counting. It is determined that the number of magnets M has been correctly counted when the first count value and the second count value coincide with each other, and the type of the rotor 4 can be determined according to the value of the magnet M.
[0019]
In this manner, the magnetic sensors H1 and H2 are arranged at both ends of the magnet mounting angle range, and when the magnet mounting angle range is set to 180 °, the magnetic sensors H1 and H2 are rotated during one rotation of the rotor 4. Will always be given twice the opportunity to detect the presence of a magnet. Further, when the magnet mounting angle range is arranged at an angle smaller than 180 °, and the magnetic sensors H1 and H2 are arranged at both ends of the mounting angle range, the magnetic sensors H1 and H2 are always at least during one rotation of the rotor 4. Once you have the opportunity to detect the presence of a magnet at the same time.
[0020]
Therefore, even if there is no other means for detecting that the rotating shaft 2 has made one rotation, the rotational speed of the rotor 4 is unknown by using signals that the magnetic sensors H1 and H2 have detected the presence of a magnet at the same time. Even if it exists, the number of magnets attached to the rotor 4 can be accurately counted.
Further, in the present invention, paying attention to the fact that the signals that the magnetic sensors H1 and H2 simultaneously detect the presence of the magnet are obtained every time the rotor 4 makes a half rotation or one rotation, this signal is used as a detection signal for the rotational speed of the rotor 4. The point to use as is also claimed.
[0021]
In other words, when the magnet mounting angle range is 180 °, as described above, the magnetic sensors H1 and H2 are given two opportunities to simultaneously detect the presence of the magnet while the rotor 4 makes one rotation. If the number of signals detected per second is N, the rotational speed of the rotor 4 per minute can be obtained by (N / 2) × 60 rpm. When the magnet mounting angle range is smaller than 180 °, it is determined at N × 60 rpm.
[0022]
Therefore, the rotational speed of the rotor 4 can be detected without attaching the rotation detecting means to the rotary shaft 2, and the maximum rotational speed determined for each type of rotor 4 is detected and the maximum rotational speed is maintained. It can be used as a control signal.
FIG. 5 shows a block diagram of the electric system of the centrifuge according to the present invention. Reference numeral 10 denotes a microcomputer. As is well known, the microcomputer 10 includes a central processing unit 11, a ROM 12, a RAM 13, an input port 14, an output port 15, and the like.
[0023]
The ROM 12 stores a startup program 12B for starting the centrifuge in a predetermined order, a verification program 12C, or a program constituting the rotor abnormality determination means 12D, and for each type of the rotor 4 shown in FIG. Assume that the rotor-specific data table 12A is stored.
The input port 14 is connected with magnetic sensors H1 and H2, and in addition, a temperature sensor 17, a vibration sensor 18, an operation panel 19 and the like.
[0024]
The output port 15 is connected to the motor 3, the refrigerator 20, the rotation speed indicator 21, etc., and the motor 3 and the refrigerator 20 are controlled to start and stop according to instructions from the microcomputer 10.
The operation panel 19 is provided with a start switch. By operating the start switch with the rotor 4 mounted, the microcomputer 10 starts executing the start program 12B.
[0025]
When the execution of the start program 12B is started, the motor 3 starts to rotate. When the rotation of the motor 3 is started, the microcomputer 10 immediately branches to a program for counting the number of magnets M by the magnetic sensors H1 and H2 even if the rotation speed is not stabilized at a constant rotation speed.
In the program for counting the number of magnets M, the number of magnets passing through either one of the magnetic sensors H1 or H2 is counted from the state in which the magnetic sensors H1 and H2 simultaneously detect the magnetic field. This counting is performed by a counter 13A configured using a partial area of the RAM 13. The counter 13A obtains the first count value and the second count value.
[0026]
When the second count value is obtained, the collation program 12C stored in the ROM 12 is activated to collate the first count value with the second count value. When a match is detected as a result of the collation, the rotor data corresponding to the matched numerical value is read from the rotor-specific data table 12A and stored in each setting unit of the RAM 13.
The microcomputer 10 controls the rate of increase (acceleration characteristic) of the rotational speed of the motor 3 according to the acceleration characteristics, for example, according to the data of the rotor 4 set in the RAM 13.
[0027]
The rotational speed measuring means 13B counts the number of times that the magnetic sensors H1 and H2 simultaneously detect the presence of the magnet, for example, every second, obtains the rotational speed per minute, for example, according to the counted value, and obtains the numerical value from the output port 15 It supplies to the rotational speed indicator 21, and displays the rotational speed for every minute. At the same time, the current rotational speed of the rotor 4 is input to the motor control program provided in the startup program 12B, the difference from the maximum rotational speed read from the rotor-specific data table 12A is obtained, and the difference value becomes zero. The drive circuit of the motor 3 is controlled so as to converge. By this control, the rotation speed of the motor 3, that is, the rotation speed of the rotor 4 is maintained at the maximum speed read from the rotor-specific data table 12A.
[0028]
According to a second aspect of the present invention, there is provided a centrifuge having a function of detecting the state when the rotor 4 starts rotating without being properly attached to the rotating shaft 2 and stopping the motor 3. suggest.
For this reason, in this invention, although the motor 3 is activated, the rotor abnormality is detected by detecting that the magnetic sensors H1 and H2 do not detect the presence of the magnet at all, and that the rotor 4 is not normally mounted. Determination means 12D is provided. In this embodiment, the rotor abnormality determination means 12D is configured by a program stored in the read-only memory 12.
[0029]
When the rotor 4 is mounted in a lifted state, the distance between the magnet and the magnetic sensors H1 and H2 increases, so that even if the rotor 4 rotates, the magnetic sensors H1 and H2 cannot detect the presence of the magnet. When this state continues for a certain period of time, the rotor abnormality determination means 12D determines that the rotor 4 is not normally mounted, and stops the driving of the motor 3.
An outline of the control program is shown in flowcharts in FIGS. First, the magnet M is counted in steps S2 to S4 shown in FIG. In step S5, the first counting of the magnet M is completed.
[0030]
In steps S6 to S8, the second magnet M is counted, and in step S9, the first and second count results are collated. If the collation results match, it is determined in step S10 shown in FIG. 7 whether or not a predetermined rotor characteristic is registered in the rotor-specific data table 12A. If it is registered data, the data is read out from the ROM in step S11, and in accordance with this data, the rotational speed is increased at an acceleration corresponding to the characteristics of the rotor in step S12. In step S13, the number of simultaneous reactions of the magnetic sensors H1 and H2 is determined. Counting is performed, the rotational speed of the rotor 4 is measured, and the maximum speed defined in the characteristics of the rotor 4 is maintained in step S14.
[0031]
If a mismatch is detected in the collation operation in step S9, the process returns to step S2 and the magnet count is executed again. Note that a counter C may be provided in the routine that returns to step S2, and the counter C may be forcibly stopped when the counter C counts, for example, “3”.
If the predetermined rotor characteristic does not exist in the data table 12A of the ROM 12 in step 10, the process branches to step S15. In step S15, it is determined that there is a possibility that the magnet of the rotor has fallen off. In step S16, a warning to that effect is displayed, and in step S17, the rotation of the motor 3 is stopped.
[0032]
If the two magnetic sensors H1 and H2 do not react at the same time in step S2 shown in FIG. 6, the process branches to step S18 shown in FIG. In step S18, the passage of time from the start of rotation is counted. Until a predetermined time elapses, the process returns to step S2 (FIG. 6). When a certain period of time has elapsed, it is determined in step S19 whether or not there has been a magnetic reaction in either the magnetic sensor H1 or H2. If there is a response in the magnetic sensors H1 and H2, the process proceeds to step S20.
[0033]
In step S20, it is determined that the rotor does not have a magnet in the position that reacts simultaneously, and in step S21, the characteristics of the rotor that does not have a magnet that reacts simultaneously (corresponding to the rotor with the rotor name G shown in FIG. 4) are acquired from the ROM. In S22, the motor 3 is driven through power limiting means for limiting the current or voltage supplied to the motor 3. By driving the motor 3 via the power limiting means, the motor 3 is driven at the slowest speed in the data table 12A, for example, 5000 rpm (estimated value).
[0034]
If there is no response from the magnetic sensor according to the rotational speed in step S19, the process branches to step S23. In step S23, it is determined that there is no rotor or a rotor is installed incorrectly, a warning to that effect is displayed in step S24, and rotation is stopped in step S25.
By selecting the arrangement angle range of the magnet M as 180 ° as in the above-described embodiment, counting can be performed twice while the rotor 4 makes one rotation. Therefore, the number of magnets M can be counted in as short a time as possible, and the advantage that the type of rotor 4 can be determined in a short time is obtained.
[0035]
However, if there is enough time to determine the type of rotor 4 (when high speed is not required for the start-up of the centrifuge), it is not always necessary to select 180 °, and an angular range of 180 ° or less Any angle can be selected. In this case, two counts can always be executed while the rotor rotates twice.
Note that the temperature sensor 17 shown in FIG. 5 is a temperature sensor that measures the internal temperature of the rotor chamber 1. When the temperature sensor 17 measures a temperature equal to or higher than a predetermined temperature, the refrigerator 20 is operated to The refrigerant is caused to flow through a pipe (not shown) wound around the outer periphery, and the operation of lowering the internal temperature of the rotor chamber 1 is performed.
[0036]
The vibration sensor 18 is attached to the motor 3, for example. When the vibration of the motor is detected and the amplitude of the vibration reaches the amplitude defined by the imbalance sensitivity in the data table 12 A for each rotor stored in the ROM 12, Control such as displaying a warning or reducing the number of revolutions of the motor 3 is performed.
[0037]
【The invention's effect】
As described above, according to the present invention, the two magnetic sensors H1 and H2 are arranged opposite to both ends of the mounting angle range of the magnet M, and the two magnetic sensors H1 and H2 are simultaneously attached to the magnet M. Since the start and end of counting of the magnets M are defined by using the signal for detecting the presence, there is an advantage that the number of the magnets M can be counted correctly without being influenced by the rotational speed of the rotor 4. Moreover, the rotational speed of the rotor 4 can be measured by using a signal for detecting the presence of the magnet at the same time. As a result, the means for discriminating the model of the rotor 4 can also be used for detecting the rotational speed of the rotor 4, so that there is no need to provide a rotation sensor using a conventionally used optical switch. Further cost reduction can be expected.
[0038]
In addition, since only two magnetic sensors are required, the number of magnetic sensors can be reduced. As a result, there is an advantage that the cost can be greatly reduced.
Furthermore, in the present invention, the position of the magnetic sensors H1 and H2 is selected to be 180 °, so that the number of magnets M can be counted twice during one rotation of the rotor 4, so the model of the rotor 4 can be selected in a short time. Can be determined. As a result, it is possible to provide an advantage that it is possible to provide a so-called quick start-up centrifuge that performs a process such as rotor specification determination at the time of startup.
[0039]
Furthermore, in the present invention, the motor 3 is stopped when the rotor 4 is not properly mounted. Therefore, the rotor 4 may reach a high speed without being normally mounted, which may lead to a serious accident. The advantage is that a highly safe centrifuge can be provided.
[Brief description of the drawings]
FIG. 1 is a side view for explaining an embodiment of the present invention.
FIG. 2 is a plan view for explaining the structure of the main part of the present invention and its operation and effect.
FIG. 3 is a plan view similar to FIG.
FIG. 4 is a diagram showing an example of the specifications of a centrifuge.
FIG. 5 is a block diagram for explaining an embodiment of the electric system of the centrifuge according to the present invention.
FIG. 6 is a flowchart for explaining an outline of a start program executed when the centrifuge according to the present invention is started.
FIG. 7 is a flowchart similar to FIG.
FIG. 8 is a flowchart similar to FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor chamber 2 Rotating shaft 3 Motor 4 Rotor 5 Fixed part M, M1-M7 Magnet H, H1, H2 Magnetic sensor 10 Microcomputer 11 Central processing unit 12 ROM
12A Rotor-specific data table 12B Startup program 12C Verification program 12D Rotor abnormality determination means 13 RAM
13A Counter 13B Rotational speed measuring means 14 Input port 15 Output port 17 Temperature sensor 18 Vibration sensor 19 Operation panel 20 Refrigerator 21 Rotational speed indicator

Claims (3)

In the centrifuge in which a rotor with various specifications is detachably attached to the rotation drive shaft, and the rotation drive characteristics of the rotation shaft are controlled according to the rotor specification,
A plurality of magnets representing the specifications of each rotor are mounted on the rotor along a circumference having the rotational drive shaft as an axis, and both ends of the mounting angle range of the magnets are fixed to a fixing portion facing the magnet mounting surface. the magnetic sensor is attached to each of the position corresponding to,
Magnetic sensor mounted on each of the positions corresponding to both ends of the attachment angle range by utilizing a signal which detected the presence of a magnet at the same time by the rotation of the rotor as a counting start signal and the terminal count signal of the magnet,
A centrifugal separator characterized in that a mounting angle range of a magnet mounted on the rotor is within 180 °. Oite the centrifugal separator of claim 1 Symbol placement, provided rotor abnormality determination means determines that the rotor is not mounted correctly in the drive shaft in a state that does not reach the number of reactions of the detection signal of the magnet plan A centrifuge characterized by having a configuration as described above. Oite the centrifugal separator according to claim 1 or 2, a centrifuge, characterized in that the arrangement for measuring the rotational speed of the rotor by a signal which the magnetic sensor detects the presence of a magnet at the same time.

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