JP3951866B2 - Centrifuge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a centrifuge, in particular, to stop the rotation of the rotor when the abnormal current flows in the motor for rotating the rotor, about subsequent centrifuge so as to release the door lock.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a centrifuge having a relatively inexpensive and simple structure is known in which a small amount of sample of about 1 to 2 ml is placed in a test tube and centrifuged. This type of centrifuge has a centrifuge body, and an opening that opens vertically upward is formed in the centrifuge body. The opening is provided with a door and a door lock mechanism . The door can close the opening, and the door lock mechanism is in a door lock state for maintaining the closed state of the opening by the door or in an unlocked state for releasing the closed state .
[0003]
The centrifuge body is provided with a motor, a rotor, and control means. The rotor is drivingly connected to the motor, and the rotor is rotated by driving the motor. The rotor is provided with a test tube holder for holding the test tube, and the test tube containing the sample is held by the test tube holder, and the rotor is rotated to perform centrifugation. The motor is connected to the control means, and the drive of the motor is controlled by the control means. The control means is also connected to the door lock mechanism , and when the user closes the door and enters the door lock state, the control means detects that fact.
[0004]
The operation of this type of centrifuge basically only turns on the power supply. More specifically, a door switch for turning on the power is provided, and the user inserts a test tube containing a small amount of sample into the centrifuge body from the opening and holds it in the test tube holder of the rotor. After closing the door, the power turns on. When the power is turned on, the control means determines that the door is closed . The control means sets the door lock mechanism in the door locked state so that the user cannot open the door, and drives the motor to rotate the rotor. The rotor is automatically stopped after continuously rotating for a relatively short predetermined time such as several seconds to several minutes at a constant rotational speed, or the motor is operated by operating a stop switch by the user while the motor is driven. The power supply to is stopped and the rotation stops. The reason that the door lock mechanism is brought into the door lock state after the door is closed is to prevent an accident when the motor is driven.
[0005]
In this type of inexpensive centrifuge, there is no rotation sensor for detecting whether or not the rotor is rotating, and the rotation speed is not detected. If the rotor does not rotate due to abnormalities such as open control elements or broken motors, it will not cause major damage if left unattended. Does not go. On the other hand, if an excessive current flows through the current limiting resistor connected to the motor due to a short circuit abnormality of the motor or an excessive current flows due to a short circuit abnormality of the control element or current limiting resistor, leave it alone. And serious damage will occur. Since no rotation sensor is provided, these abnormalities cannot be detected due to abnormal rotation speeds.However, assuming that these abnormalities will occur in advance, a fuse or current limiting resistor is installed, or a temperature sensor is installed in the motor. It was detected by installing it, and when an abnormality occurred, the operation of the entire centrifuge was stopped.
[0006]
[Problems to be solved by the invention]
However, in the conventional centrifuge, because the abnormality when occurs centrifuge entire operation with the driving of the motor is stopped from being stopped, but than it can be prevented the damage caused by abnormalities in advance, the door lock Since the mechanism is completely stopped while the mechanism is kept in the door lock state, the user cannot easily open the door.
[0007]
Therefore, the present invention provides a centrifuge capable of opening the door of the centrifuge body after stopping the rotation of the centrifuge rotor when there is an abnormality such as a short circuit abnormality of the motor.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention detects a centrifuge body in which an opening is formed, a door capable of closing the opening , detecting that the door is in a closed position, and outputs a signal to that effect. A door switch that is generated , a door lock mechanism that maintains a closed state of the opening by the door, or an unlocking state that releases the closed state, and a sample that is inserted through the opening a rotatable rotor for placing a test tube enters, a motor for providing rotational force to the rotor, the motor receives the signal of the door switch when it is detected that the opening by the door is closed a centrifugal machine having a control means for starting the drive, and a first switching element connected in series to the motor, a second switching element connected in parallel to the motor, the series to the motor Connect to A current detecting element, the door lock mechanism and the door locked in the off state, and the door lock switching element for the door lock mechanism unlocked to the on state, the operation when stopping the rotation of the rotor And a stop switch that generates a signal to that effect , wherein the control means receives the door switch signal and turns on the first switching element and turns off the second switching element. driven by receiving a detection signal of the current detection element to detect whether or not an abnormal state, the abnormal state detected turned off said first switching device when, the motor said second switching element is turned off The door lock switching element is turned on after the second predetermined time has elapsed after the natural deceleration and the natural deceleration. After the first predetermined time has elapsed after receiving the signal from the stop switch, the first switching element is turned off, the second switching element is turned on and the motor is forcibly braked and forcibly braked. A centrifuge is provided in which the door lock switching element is turned on and the door lock mechanism is unlocked .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
A centrifuge 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. The centrifuge 1 has a centrifuge body 10 having a substantially dome shape, and an opening 10a that opens vertically upward is formed in the upper part thereof. In the vicinity of the opening 10a and at the right end in FIG. 1, a door 11 having a substantially semicircular cross-sectional view is hinged. The door 11 can be closed so as to cover the opening 10a in a dome shape. At the same time, it is rotatable about the position where it is hinged. The door 11 is urged by a spring (not shown) in a direction in which the door 11 opens, that is, substantially vertically upward, and when a door lock mechanism 20 described later is not in a door lock state and no force is applied to the door. The door 11 is configured to be in a half-open state in which the door 11 is slightly opened.
[0010]
A door lock mechanism 20 is provided at the left end position in FIG. 1 of the opening 10a. The door lock mechanism 20 includes a claw portion 21 that is rotated by a solenoid about a predetermined axis, and a claw portion 21. And a door lock device 22 having a solenoid to be rotated. Moreover, the door switch 23 which detects that the door 11 was closed by the user is provided in the position of the left end in FIG. 1 of the opening part 10a. A claw engaging portion 11 </ b> A is provided at the left end of the door 11 in FIG. 1 and facing the claw portion 21.
[0011]
The door lock mechanism 20 is opened by the door 11 when the claw portion 21 is turned in a non-rotatable state after the claw portion 21 is rotated about a predetermined axis and engaged with the claw engagement portion 11A. It will be in the door lock state in which the closed state of the part 10a is maintained. When the door is locked, the user cannot open the door 11. Further, the door lock mechanism 20, the pawl portion 21 is disengaged from the claw engagement portion 11A is rotated becomes unlocked, are half-open the door 11 is slightly opened by not shown springs .
[0012]
As will be described later, the door lock device 22 is connected to the control means 32 via the door lock switching element 33, and the claw portion 21 is operated via the solenoid under the control of the control means 32 so that the door lock state or the door is locked. Unlocked. In addition, a stop switch 10A is provided outside the centrifuge 1 and in the vicinity of the opening 10a and in the vicinity of the position where the door lock mechanism 20 is provided. When the stop switch 10A is pressed at any time during rotation, the rotation of the rotor 24 can be stopped in a short time.
[0013]
Inside the centrifuge body 10, a rotor 24, a motor 25, a control board 30 and a power supply unit (not shown) are provided. The control board 30 is provided with a control means 32 composed of a CPU or the like. The motor 25 is connected to the control means 32 and a power source, and is configured to be driven by control by the control means 32. When the motor 25 is driven, the rotor 24 accelerates from a state where the rotational speed is zero, and after reaching the constant rotational speed, the rotor 24 is controlled to rotate at the constant rotational speed. The output shaft 25A of the motor 25 is directed vertically upward, and the rotor 24 is fixed so as to cover the output shaft 25A. The rotor 24 is provided with a test tube holder 24A that can hold and hold the six test tubes 2 containing the sample to be centrifuged at an angle of approximately 45 degrees. The test tube 2 is rotated integrally with the output shaft 25A while being held. The test tube 2 can be placed on the test tube holder 24A only when the door 11 is open.
[0014]
As shown in FIG. 2, the control board 30 includes a rectifier 31, a control means 32, a door lock switching element 33, a current limiting resistor 34, a first switching element 35, and a second switching element 36. The current detection element 37 is provided. The control unit 32 performs control based on data stored in a memory inside the control unit 32 . The rectifier 31 rectifies the alternating current. A door switch 23 of the door lock mechanism 20 is connected between the rectifier 31 and the control means 32. The control means 32 is connected to the solenoid of the door lock mechanism 20 via the door lock switching element 33.
[0015]
When the door lock switching element 33 is turned off, the door lock mechanism 20 is changed from the unlocked state to the door locked state, and when turned on, the door lock mechanism 20 is changed from the door locked state to the unlocked state. It is configured. When the closed state of the door 11 is detected by the door switch 23, that is, when the door switch 23 is turned on, the control means 32 turns off the door lock switching element 33 and puts the door lock mechanism 20 into the door locked state. At the same time, control by the control means 32 is started. The current limiting resistor 34 is connected to the rectifier 31 via the door switch 23 and connected in series to the motor 25 via the first switching element 35, and limits the current flowing to the motor 25.
[0016]
The first switching element 35 is connected to the motor 25 in series. A second switching element 36 is connected in parallel to the motor 25, and the first switching element 35 and the second switching element 36 are respectively connected to the control means 32. When the door switch 23 is turned on, the control means 32 turns off the second switching element 36 and turns on the first switching element 35 to drive the motor 25 so that a current flows through the motor 25. Let When the stop switch 10A is pressed while the motor 25 is being driven, the first switching element 35 is turned off and the second switching element 36 is turned on to stop the supply of current to the motor 25 and the motor. The motor 25 is stopped in a short time by forced braking or power generation braking using the back electromotive force generated at 25.
[0017]
The motor 25 is further connected with a current detection element 37 in series to detect the current flowing through the motor 25. The current detection element 37 is also connected to the control means 32, and outputs information related to the current flowing through the motor 25 to the control means 32. Information indicating that no current is flowing in the current detection element 37 is output from the current detection element 37 to the control means 32 while the motor 25 is being driven, or information indicating that an excessive current is flowing in the motor 25. Is detected from the current detection element 37 to the control means 32, the control means 32 turns off both the first switching element 35 and the second switching element 36 to the motor 25. Is stopped, and the rotation of the rotor 24 is stopped. The control is different from when the rotation of the rotor 24 is stopped by the stop switch 10A. The reason why the motor 25 is not forcibly braked is to prevent the secondary element from being damaged due to the overcurrent.
[0018]
Next, operation | movement of the centrifuge 1 is demonstrated based on the flowchart of FIG. First, the user puts a sample to be centrifuged in the test tube 2 in advance. Then, the test tube 2 containing the sample is placed on the test tube holder 24A of the rotor 24, and the test tube 2 is held by the test tube holder 24A. At this time, the control means 32 is in a standby state in which it is determined whether or not the door switch 23 is on (S1: NO).
[0019]
Next, when the door 11 is closed by the user and the door switch 23 is turned on (S1: YES), the control means 32 starts control, turns off the door lock switching element 33, and the second switching element 36. Is turned off, and the first switching element 35 is turned on (S2). When the door lock switching element 33 is turned off, the door lock device 22 of the door lock mechanism 20 is brought into the door lock state. The second switching element 36 is turned off, the first switching element 35 by the other by being turned on, the power supply to the motor 25 via a current limiting resistor 34 is started .
[0020]
Next, when an abnormality is detected such that a current value equal to or greater than a certain value (X) is detected in the current detection element 37 (S3: YES), the first switching element 35 is turned off, and the second The switching element 36 is turned off, and the current supply to the motor 25 is stopped (S4). Even when a current value equal to or greater than a certain value (X) is not detected in the current detection element 37 (S3: NO), an abnormality is detected such that a current value equal to or less than a certain value (Y) is detected. (S5: YES), similarly, the first switching element 35 is turned off and the second switching element 36 is turned off to stop the current supply to the motor 25 (S4). At this time, the first switching element 35, has a both turned off the second switching element 36, because in a state of circuit portion motor 25 is connected is disconnected, forced braking motor 25 Not . Therefore, after the power supply to the motor 25 is stopped, the rotor 24 rotates with inertial force, and naturally decelerates and stops rotating. Then, it is determined whether or not a certain time T2 has elapsed, that is, whether or not the time necessary for the rotor 24 to completely stop rotating has elapsed (S6). If T2 has elapsed ( (S6: YES), the door lock switching element 33 is turned on to bring the door lock device 22 into the unlocked state (S7), the door 11 is opened by a biasing force by a spring (not shown), and the control is terminated.
[0021]
The magnitude relationship between the constant values (X) and (Y) is X> Y. T2 is a value obtained by conducting an experiment in advance and giving a slight margin to the time taken from the stop of the power supply to the motor 25 until the rotation of the rotor 24 completely stops. The T2 data is stored in a memory (not shown).
[0022]
On the other hand, if a current value equal to or greater than a certain value (X) is not detected in the current detection element 37 (S3: NO) and a current value equal to or less than a certain value (Y) is not detected (S5: NO), it is determined whether or not the stop switch 10A has been turned on, that is, whether or not the stop switch 10A has been pressed by the user (S8). If the stop switch 10A is not turned on (S8: NO), it is determined again whether or not an abnormality is detected such that a current value equal to or greater than a certain value (X) is detected in the current detection element 37. (S3). When the stop switch 10A is turned on (S8: YES), the first switching element 35 is turned off and the second switching element 36 is turned on (S9). When the first switching element 35 is turned off and the second switching element 36 is turned on, the current supply to the motor 25 is stopped, the motor 25 is forcibly braked, and the motor 25 is stopped in a short time. Is done. Then, it is determined whether or not a certain time T1 has elapsed, that is, whether or not a time necessary for the rotor 24 to completely stop rotating has elapsed (S10), and if T1 has not elapsed (S10). S10: NO), and wait until T1 has elapsed. If T1 has elapsed (S10: YES), the door lock switching element 33 is turned on to bring the door lock device 22 into an unlocked state (S7), and the door 11 is opened by the biasing force of a spring (not shown) and controlled. Exit.
[0023]
Note that T1 is a value obtained by conducting an experiment in advance, as in T2, with a slight allowance for the time taken from the stop of power supply to the motor 25 until the rotation of the rotor 24 completely stops. It has become. This T1 data is stored in a memory (not shown). The magnitude relationship between the fixed times T1 and T2 is T2> T1. In S9, the first switching element 35 is turned off and the second switching element 36 is turned on to forcibly brake the motor 25, which brakes the rotation of the motor 25. This is because the motor 25 can be stopped in a shorter time than in the case of the natural deceleration S4.
[0024]
It is possible to predict the current flowing through the motor 25 when the motor 25 is normally driven. Further, when the motor 25 is driven, the rotor 24 accelerates from a state where the rotational speed is zero, and after reaching the constant rotational speed, the rotor 24 is configured to rotate at the constant rotational speed. After the power supply to the motor 25 is stopped, it is possible to predict the time until the rotor 24 naturally decelerates and the rotor 24 completely stops rotating. Based on these predicted values, an abnormality in the motor 25 is detected, the rotation of the rotor 24 is stopped, and after the rotor 24 has completely stopped rotating, the door lock is released and the door 11 is opened. In addition, the problem that the door 11 cannot be opened when an abnormality occurs and the rotor 24 stops rotating can be solved, and the convenience of the customer can be improved.
[0025]
The centrifuge according to the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made within the scope described in the claims. For example, in this embodiment, it is determined whether or not the stop switch 10A is on in S8 of the flowchart shown in FIG. 3, and if it is not on (S8: NO), the process immediately returns to S3. However, instead of immediately returning to S3, it may be determined whether or not a predetermined time has elapsed since the door switch 23 was turned on. In this case, if the predetermined time has elapsed in the determination, the process of S9 is performed next, and if the predetermined time has not elapsed, the process returns to S3. By doing so, the rotor 24 can be automatically stopped after the door switch 23 is turned on and the rotor 24 continues to rotate for a predetermined time.
[0026]
【The invention's effect】
According to the centrifuge of claim 1 , when an abnormality is detected by the current detection element during driving of the motor by the motor control means, the power supply to the motor is stopped, and the door lock mechanism is Since the door is unlocked so that the door can be opened, the problem that the door cannot be opened when an abnormality occurs and the rotor stops rotating can be improved, and the convenience of the customer can be improved. it can.
[Brief description of the drawings]
FIG. 1 is a sectional view of a centrifuge provided with a door lock mechanism according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a door lock mechanism of the centrifuge according to the embodiment of the present invention.
FIG. 3 is a flowchart showing a release control method of the door lock mechanism of the operation and the centrifuge of the door lock mechanism of a centrifuge according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Centrifuge 2 Test tube 10 Centrifuge body 10a Opening part 11 Door 20 Door lock mechanism 21 Claw part 22 Door lock device 23 Door switch 24 Rotor 25 Motor 32 Control means 33 Door lock switching element 34 Current limiting resistor 35 First switching Element 36 Second switching element 37 Current detection element

Claims (1)

A centrifuge body in which an opening is formed,
A door capable of closing the opening;
A door switch that detects that the door is in the closed position and generates a signal to that effect;
And the door lock mechanism to the unlock state to release the or the closed state to the door lock state to maintain the closed state of the opening by the door,
A rotatable rotor for mounting a sample-containing test tube to be inserted through the opening;
A motor for applying a rotational force to the rotor ;
A centrifuge and a control means for opening is to start driving of the door switch the motor receives a signal when it is detected that has been closed by the door,
A first switching element connected in series to the motor;
A second switching element connected in parallel to the motor;
A current detection element connected in series to the motor;
A door lock switching element that turns the door lock mechanism into a door lock state when in an off state, and that unlocks the door lock mechanism when in an on state ;
A stop switch that is operated when the rotation of the rotor is stopped and generates a signal to that effect ,
The control means includes
Receiving the door switch signal, turning on the first switching element, turning off the second switching element, and driving the motor;
Upon receiving a detection signal from the current detection element, it is detected whether or not it is in an abnormal state, and when the abnormal state is detected, the first switching element is turned off, the second switching element is turned off, and the motor is naturally decelerated. The door lock switching element is turned on and the door lock mechanism is unlocked after a second predetermined time has elapsed after natural deceleration.
In response to the signal from the stop switch, the first switching element is turned off, the second switching element is turned on, the motor is forcibly braked, and the door is locked after a first predetermined time has elapsed after forcibly braking. A centrifuge characterized in that a switching element is turned on and the door lock mechanism is unlocked .

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