JP3509324B2 - Centrifuge - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety control device for an air leak valve for preventing a malfunction of an air leak valve for opening a vacuum chamber to atmospheric pressure. It is about. 2. Description of the Related Art In a conventional ultracentrifuge, a chamber for accommodating a rotor is evacuated to a high vacuum with a vacuum pump or a diffusion pump in order to minimize windage loss of a rotor rotating at a high speed. The operation of rotating the rotor at high speed and removing the rotor from the chamber is performed by stopping the operation of the vacuum pump, operating the air leak valve that communicates the chamber with the atmosphere, and opening the chamber to atmospheric pressure. The door provided at the top of the chamber was opened. In these centrifuges, the operation of the vacuum pump, the diffusion pump and the air leak valve, the high-speed rotation control of the rotor, and the like are controlled by a CP built in the ultracentrifuge.
U receives a command by a key operation from the operation panel, outputs an operation content to the control device, and performs control. In such a conventional centrifuge, since a control device operates according to a control command from a CPU, external noise arriving at the centrifuge or a built-in control device is required. CPU due to internal noise emitted from the device
Malfunctions, the air leak valve operates erroneously while the rotor is rotating at high speed in the chamber maintained in a high vacuum state, and the rotor that is rotating in the chamber is lifted from the crown by buoyancy or frictional force due to windage loss There is a problem that the rotor itself, the chamber itself, or the rotation drive unit of the rotor may be damaged. [0004] It is an object of the present invention to provide a centrifuge equipped with an interlock device which does not operate the air leak valve even if the CPU malfunctions, eliminating the above-mentioned disadvantages of the prior art. SUMMARY OF THE INVENTION The object of the present invention is to provide a chamber capable of accommodating a rotor and evacuating and sealing, an air leak valve for opening the chamber to atmospheric pressure, opening and closing of the air leak valve, and other functions of a vacuum pump. In a centrifuge provided with a CPU for controlling operation and rotation speed of a rotor, interlock means is provided on a control line output from the CPU to the air leak valve, and the interlock means is provided for the CPU.
And a valve opening signal output from the rotor speed detecting means. According to the safety device of the centrifuge constructed as described above, the rotation speed detecting means detects the rotation speed of the rotor independently of the control operation of the CPU and detects the rotation speed of the rotor. When the rotation speed is lower than the predetermined rotation speed, the CPU operates to output a valve opening signal. Therefore, while the rotor is rotating at a high speed, the CPU malfunctions for some reason and the valve opening signal for erroneously opening the air leak valve is interrupted. Even if the signal is output to the lock means, since the valve opening signal is not output from the rotation speed detecting means to the other input end of the interlock means, the air leak valve is prevented from being erroneously operated in such a case, On the other hand, when the air leak valve is operated to open the chamber to the atmospheric pressure, open the door, and take out the rotor, the rotation of the rotor is stopped and the rotation speed detecting means does not allow the rotation to be interrupted. Since the valve opening signal is output to the locking means, if the CPU receives an air leak command by a key operation from the operation panel, a valve opening signal is output from the CPU to the interlock means to operate the air leak valve. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1 shows a specific embodiment of the present invention.
Reference numeral 1 denotes a rotor, 2 denotes a motor that drives the rotor 1 to rotate, 3 denotes a motor drive device such as an inverter that supplies rotational energy to the motor 2, and 4 denotes an identifier embedded in the lower surface of the rotor 1. In the example, a magnet 5 is a first sensor comprising a Hall element or a magneto-resistive element or a pickup coil for detecting the presence of the magnet 4, an operation panel 6 such as a keyboard and a display, a vacuum pump 7 A vacuum pumping device comprising a fusion pump, and 8 is a first processor serving as a CPU. The first processor 8 outputs a rotation speed control signal to the motor driving device 3 via the control line 9 in accordance with the operation command input from the operation panel 6, inputs the output signal of the first sensor 5, The type code of the rotor, i.e., the ID, and the actual number of revolutions are measured, and the evacuation device 7 and the air leak valve 52 are controlled. Reference numeral 10 denotes a first shut-off device for the first processor 8 to arbitrarily shut off supply of rotational energy from the motor driving device 3 to the motor 2, and 11 denotes a first shut-off device 1 from the first processor 8.
This is a control line that outputs a shutoff operation signal to 0. 15 is the first
A second method for detecting the presence of the magnet 4 similar to the sensor 5 of FIG.
Sensor 16 is a second sensor for detecting the rotation speed of the rotor 1.
The processor receives the output signal of the second sensor 15 independently of the first processor and measures the type code of the rotor 1 which is the so-called iD of the rotor 1 and the actual number of revolutions. Reference numeral 17 denotes a second interrupting device for the second processor 16 to arbitrarily interrupt the supply of rotational energy from the motor driving device 3 to the motor 2, and is provided separately and independently from the first interrupting device 10. The first interrupting device 10 and the second interrupting device 17 are arranged in series with each other with respect to a rotational energy control supply path for interrupting the supply of rotational energy from the motor driving device 3 to the motor 2. When any one of the shut-off devices operates, the supply of rotational energy to the motor 2 is shut off, and the motor 2 stops rotating. Reference numeral 18 denotes a control line for outputting a shutoff operation signal from the second processor 16 to the second shutoff device 17. The control lines between the first processor 8, the operation panel 6, and the evacuation device 7
Shown at 2 and 13. Reference numeral 14 denotes a rotational energy supply line between the motor drive device 3 and the motor 2, and reference numeral 50 denotes a sensor for detecting supply energy provided between the rotational energy supply line 14 and 14A. For example, a current sensor having a winding type or a Hall sensor and an appropriate amplification / smoothing circuit, and an output signal thereof is input to an A / D conversion input terminal AD2 of the second processor 16. Reference numeral 53 denotes a chamber for accommodating the rotor 1 and the motor 2, and reference numeral 59 denotes a door for taking the rotor 1 in and out. A pipe 54 extends from the chamber 53 to the evacuation device 7 and the air leak valve 52. Reference numeral 55 denotes a driver for opening and closing the air leak valve 52, and reference numeral 56 denotes an interlock means such as an AND gate for outputting a signal to the driver 55. The interlock means 56 includes a first processor, that is, a CPU 8 and a second processor. That is, a valve opening / closing signal is output from the rotation speed detecting means 16 to the interlock means 56 via the control lines 57 and 58, respectively. The operation of opening the air leak valve 52, that is, the operation of opening the chamber 53 to the atmospheric pressure, is performed by controlling the control lines 57 and 58.
Are output from the CPU 8 and the rotational speed detecting means 16 respectively, and the logical product is taken by the interlock means 56, and the signal output becomes the "Lo" level. The operation is performed by operating the air leak valve 52 and opening the valve. FIG. 2 shows the operation panel 6 of the safety control device 100 for the air leak valve of the centrifuge shown in FIG.
FIG. 2 is a block circuit diagram of a portion excluding the evacuation device 7, and portions having the same functions as those in FIG. 1 are denoted by the same reference numerals. In the motor driving device 3, reference numeral 19 denotes an AC power source or the like. The power supply of the motor drive device 3 of the present invention, 20 is an inverter control device, and 21, 22, and 23 are, for example, power transistors and IGs for supplying three-phase power to the induction motor 2, respectively.
This is a power bridge composed of power elements such as BT and GTO, and 14A, 14B, and 14C are connected as supply lines 14 of rotational energy from the arms of the power bridges 21, 22, and 23 to the motor 2, respectively. In this case, the sensor 50 is clamped to the rotational energy supply line 14A. The power elements in the case of the upper arm and the lower arm iGBT, which represent the power bridge 21 and constitute the power bridge, are indicated by 24 and 25, and 26 and 27 are gate control circuits of the power elements 24 and 25, respectively. The ignition signals are sent from the photocouplers 28 and 29. 30 is a photocoupler 28, 29
Is a power source for lighting the light emitting elements of the inverter control device 2 via the resistors 31 and 32, respectively.
The power elements 24 and 25 are turned on by turning on and off the light emitting elements of the photocouplers 28 and 29, respectively, and rotational energy is supplied to the motor 2.
Accordingly, when the second interrupting device 17 including a semiconductor switch such as a transistor, a relay, and the like connected between the power supply 30 and the resistors 31 and 32 is interrupted by the control line 18, the power bridges 21, 22, and 23 are closed. The power supply for turning on the light emitting element is cut off, and the supply of rotational energy to the motor 2 is cut off no matter what command is input to the inverter control device 20 from the control line 9 of the rotation speed control signal. Has become. Similarly, a first shut-off device 1 including a semiconductor switch such as a triac, a relay, and the like.
Numeral 0 is provided between the power supply 19 and the inverter control device 20, and when the first shutoff device 10 is shut off by the control line 11, the supply of rotational energy to the motor 2 is shut off. I have. In the first processor 8, 33 is a CPU, 34 is a clock generator, and 35 is a reset circuit, which outputs signals to the CPU 33, respectively.
The signal output of the clock generator 34 is output to C
It is output to the timer interrupt terminal T1 of the PU 33.
37 is a frequency divider of 2 of the first sensor 5, and a signal output is an event interrupt input terminal EV1 of the CPU 33, respectively.
1, EV12 and EV13. Similarly, in the second processor 16, 38 is a CPU, 39 is a clock generator, and 40 is a reset circuit.
A signal is output to the PU 38, and the signal output of the clock generator 39 is output to the timer interrupt terminal T2 of the CPU 38 via the frequency divider 41.
A frequency divider, whose signal output is an event interrupt input terminal EV21, EV22, EV23 of the CPU 38, respectively.
Has been entered. The output of the current sensor 51 is the first
The output signal is inputted to the A / D conversion terminal AD1 of the processor 8 of FIG. FIG. 3 shows a configuration for detecting a rotation signal of the rotor 1. The same functions as those in FIGS. 1 and 2 are denoted by the same reference numerals. The magnets 4, which are a plurality of identifiers embedded on the same circumference, have the first sensor 5, the second sensor 15, and the 4AS and 4BS whose S poles are directed at the S pole so as to form an angle θ with respect to the rotation center O. And magnets 4AS, 4B
The balancers 4AN and 4BN are arranged at positions where the counter balance is obtained with respect to S, that is, at positions that are point-symmetric with respect to the magnets 4AS and 4BS. In this embodiment, the first sensor 5 and the second sensor 15 use the magnet 4A as the rotor 1 rotates.
The balancers 4AN and 4BN are configured by magnets having N poles directed to the first sensor 5 and the second sensor 15, and for example, the first sensor 5 Is the S pole magnet, ie, magnet 4
AS and 4BS may be detected, and the second sensor 15 may detect an N-pole magnet, that is, the magnets 4AN and 4BN. Naturally, the relationship between the SNs is the same even if the relationship is reversed. With this configuration, it is possible to solve problems caused by the magnet itself, such as a loss of a signal from the magnet, a decrease in the magnetic force of the magnet, and a loss of the magnet itself. FIG. 4 is a timing chart showing the operation of the second processor 16 with respect to the signal output of the rotation sensor 15 shown in FIG. 4 and the operation of the second processor 16 shown in FIGS. When the rotor 1 is rotated by supplying rotational energy from the motor driving device 3 to the motor 2 and the rotor 1 rotates, as shown in the signal output 43 of the second sensor 15 in FIG.
Two pulses are output from the second sensor 15 for one rotation of the second frequency divider 42, and as shown by the signal output 44 of the two frequency divider 42, the two frequency divider 42 outputs the event interrupt terminal EV2 of the CPU 38.
1, a divided signal is given to EV22 and EV23. CP
U38 is a microcomputer M3 manufactured by Mitsubishi Electric
In the example using the 7451, at the rising portion 44H of the signal output 44 of the frequency divider 42 provided to the signal input terminal EV21 of the CPU 3, FIG.
4. The event interrupt EVR1 in the pulse cycle measurement mode of the processing flow of FIG. 5 is generated, and the clock of the clock generator 34 in the clock count number range 45 of the RCNT in the time T section for one rotation of the rotor 1 shown in FIG. The frequency-divided clock, for example, 3 MHz, is transferred to the memory RCNT in the CPU 38. Similarly, at the rising edge 44H of the signal output 44 of the frequency divider 42 given to the signal input terminal EV22 of the CPU 38, the pulse width measurement mode in the logic "Hi" section of the processing flow of FIG. The event interrupt EVR2 is generated, and the iDH in the TH section shown in FIG.
The number of clocks in the CNT clock count range 46 is transferred to the memory iDHCNT in the CPU 38. Further, similarly, at the falling portion 44L provided to the signal input terminal EV22 of the CPU 3, an event interrupt EVR3 of the pulse width measurement mode in the logic “Lo” section is generated,
By the process 103, the number of clocks in the clock count range 47 of the iDLCNT in the TL section shown in FIG.
To the internal memory iDLCNT. Subsequently, the frequency divider 4
1 is output to the T2 timer interrupt terminal of the CPU 38, the timer interrupt iNT1 shown in FIG. 6 is generated at a cycle of, for example, about 100 msec.
04, the actual number of revolutions of the rotor 1 is calculated from the value of the memory RCNT by the following equation (1). The data is stored in the memory RRPM. In step 105, the type code iDθ of the rotor 1 corresponding to the angle θ in FIG. 5 is discriminated and calculated from the values of the memories iDHCNT and iDLCNT by the following equations (2) and (3), and stored in the memory. ## EQU2 ## [Equation 3] Subsequently, in step 106, the maximum allowable rotational speed RMAX of the rotor 1 is determined from the value of the memory iDθ by, for example, the following equation (4) and stored in the memory. [Equation 4] FIG. 7 shows the actual rotational speed RRPM of the rotor 1 and the type code iD which are sequentially obtained by the CPU 38 during the rotation of the rotor 1.
Maximum allowable rotation speed RMAX calculated from θ and type code
Based on the above, the shut-off operation signal and the rotation speed detecting means 16 are sent to the second shut-off device 17 from the control line 58 by the air leak valve 52.
9 shows a CHECK processing flow for determining whether or not to output the open signal of the second embodiment. In step 107, the shutoff signal and the valve open signal are first turned off by the process 107, and the second shutoff device 17 is turned off by the control line 18. Then, the photocouplers 28 and 29 of the power bridge 21 are connected to the power supply 30 and become operable by the control operation of the inverter control device 20, while the air leak valve 52 is closed. The cycle of the judging process is adjusted to an appropriate interval by the one-second timer of the process 108, and the process branches to the judgment 109 while the actual rotation speed of the rotor is not 0 by the judgment 114, and the judgment 109
As a result, the actual rotation speed of the rotor 1 is low, for example, 100
If the rotation is equal to or less than 0, the opening signal of the air leak valve 52 is output ON from the control line 58 of the rotation speed detecting means 16 by processing 118 for replacing the rotor to be set in the centrifuge. , And a decrease in the rotation speed of the rotor 1 due to a power failure,
The determination of the shutoff operation is prohibited due to a measurement error or the like. When the actual rotation speed of the rotor 1 exceeds 1000 rotations, the opening signal of the air leak valve 52 is turned off by the processing 117.
The air leak valve 52 is not opened even if the opening signal is output from the CPU 8 and the actual rotation speed RPPM exceeds the maximum rotation speed RMAX due to some trouble of the centrifuge.
Then, the second interrupting device 17 is turned off by the control line 18, the supply of rotational energy from the motor driving device 3 of the motor 2 is interrupted, the rotation speed of the rotor 1 stops decreasing, and the rotation of the rotor 1 of the centrifuge is stopped. Safety against over rotation is ensured. At this time, since the process 113 of turning off the cutoff signal is repeatedly executed, the power of the control device 100 is once turned off, and the cutoff device 17 is kept in the cutoff state and the safety is protected until the reset signal is input again from the reset circuit 40. It has become so. The type code iDθ of the rotor 1 is, for example, 8
If the value is not more than {less than or 175} or more, the processing 113 is executed by the determination processings 111 and 112, respectively. Such a state is shown in FIG.
Either one of the 4BSs is dropped or missing or the second sensor 1
5 due to poor sensitivity to one of the magnets 4AS and 4BS.
Becomes one pulse for one rotation of the rotor 1 and is divided into two frequency dividers 4
2, the duty of “Hi” and “Lo” becomes 50%, and the measured value of iDθ becomes θ ゜, 180
It also includes detecting a value close to ゜. On the other hand, according to the determination 114, the actual rotation speed of the rotor 1 is 0 rotation per minute,
That is, when the rotation of the rotor 1 is stopped, the opening signal of the air leak valve 52 is turned on by the processing 116 and the CPU
The air leak valve 52 is controlled in accordance with the opening signal from the controller 8, and the process branches to decision 115. The CPU 38 A / D converts the analog output of the current sensor 50 from the AD2 terminal, recognizes the analog output as a digital amount, compares the analog output with a predetermined value, and compares the analog output with the predetermined value. It is checked whether or not the drive energy is supplied, and if it is determined that there is a current, the process branches to step 113, and the second interrupting device 17 is turned off by the control line 18 in the same manner as described above, and the motor 2 The supply of rotational energy from the driving device 3 is cut off. In FIG. 3, such a state is caused by a drop or loss of any of the magnets 4AS and 4BS or a poor sensitivity of the second sensor 15 to any of the magnets 4AS and 4BS.
A signal output of 5 does not appear despite the rotation of the rotor. In the above determination 115, the CPU 3
If it is determined that there is no current, the flow branches to step 108 to repeatedly execute the above determination and processing. In such a state, no energy is supplied to the motor 2 and the rotor 1 simply stops rotating. Needless to say, this corresponds to a state.
Here, in the above specific embodiment, the current sensor 5
Although the output of 0 is input to the CPU 38 to prevent the rotor 1 from over-rotating, a current sensor similar to the current sensor 50 may be connected to one of the rotational energy supply lines 14 separately from the current sensor 50.
4B or 14C, the current signal is input to the CPU 33 and the judgment is also performed on the CPU 33 side in the same manner as when the output signal of the current sensor 50 is input to the CPU 38.
4. It is also possible to simultaneously execute the determination processes corresponding to the determination 115 and the process 113 in parallel to prevent the rotor 1 from over-rotating due to a malfunction of the magnets 4AN, 4BN or the first sensor 5. It is clear in light of the idea of the present invention. The operation of the above-described specific embodiment will be described with reference to the second processor 16 for the signal output of the rotation sensor 15.
Has been described, the control operation of the first processor 8 for preventing the rotor 1 from over-rotating in response to the signal output of the rotation sensor 5 is also performed by connecting the control line 9 to the motor driving device 3 in accordance with the operation command input from the operation panel 6. The operation is the same as that of the above-described second processor, except that a rotation speed control signal is output via the control unit, and control processing of a normal centrifuge related to execution of control of the evacuation device 7 is performed. In a block circuit diagram partially showing another embodiment of the present invention, in FIG. 9, portions having the same functions as those in FIG. Instead, the signal output of the second sensor 15 is converted to a frequency-voltage converter (hereinafter, referred to as an F / V converter) 60.
And the output of the F / V converter 60 to a comparator 61
The output control line 58 of the comparator 61 is at the “Lo” level when the rotation speed of the rotor 1 is lower than the predetermined rotation speed, and when the rotation speed of the rotor 1 is lower than the predetermined rotation speed, The configuration and operation are performed as follows. On the other hand, the interlock means 56 is shown in another embodiment, and the driver 55 is supplied with power from the DC source VCC through the transistor 64, and operates by the "Lo" level signal output of the control line 57 of the CPU 8. The output of the output control line 58 of the comparator 61 is “L”
When it is at the "o" level, the transistor 6
4, the base current flows, and the power supply VCC is supplied to the driver 55, so that the driver 55 is operable. As described above, in any of the embodiments, if the rotation speed of the rotor 1 is equal to or lower than the predetermined rotation speed by the rotation speed detecting means 16, the driver 55 operates according to the signal output of the control line 57 of the CPU 8, and the air leak is performed. The valve 52 is arbitrarily controlled. However, when the rotation speed of the rotor 1 becomes equal to or higher than a predetermined number, the driver 55 does not operate even if the CPU 8 erroneously outputs a valve opening signal to the control line 57 due to the operation of the interlock means 56. The air leak valve 52 is never opened, so that air leak during rotation of the rotor 1 is prevented and safety is maintained. In FIG. 8 of a block circuit diagram partially showing another embodiment of FIG. 2, parts having the same functions as those of FIG. 10 is a driver 48, 4 such as a three-state gate buffer,
An example using No. 9 is shown. The first breaking device 10 and the second breaking device 17 are provided in series with the lighting paths of the light emitting elements of the photocouplers 28 and 29, and the logic “H” of the control line 11 is used.
The driver 48, 49 enters the high resistance state by the signal output of "i", and the motor driving device 3
Is shut off. Further, a third processor and a third sensor are used to detect over-rotation of the rotor, determine an abnormality in the type code of the rotor, and cut off supply of rotational energy from the motor driving device 3 to the motor 2. First shut-off devices 1 arranged in series with each other with respect to the rotational energy control supply path
A redundant configuration in which a third shutoff device is provided in series with the zero and second shutoff devices 17 and a third processor outputs a shutoff signal when an abnormality is determined in the shutoff device is also an idea of the present invention. Things. The detection mechanism for measuring the rotor type code and the actual number of revolutions employs optical detection, detection by ultrasonic waves, detection by electromagnetic waves, and the like in addition to magnetic detection as in this embodiment. By doing so, it goes without saying that the present invention can be implemented, and furthermore, the position and angle or the number of indexes provided on the rotor, a complex index pattern, a magnetic storage medium, and an optical storage. The present invention can be implemented even if a means for detecting with a medium is employed. According to the present invention, the control output from the CPU and the rotational speed of the rotor are detected in the opening / closing control of the air leak valve for opening the chamber to the atmospheric pressure. For example, the interlock means for outputting the valve open signal and outputting the valve open signal in the other state and matching the control output of the rotor speed detecting means is provided, so that the CPU malfunctions during the high speed rotation of the rotor. Even if a control output that opens the air leak valve is output, the air leak valve does not operate, so the air leak valve opens while the rotor is rotating at a high speed, and the rotor comes off the crown,
It is possible to prevent such a problem that the rotor itself, the chamber and the drive unit are damaged.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a safety control device for an air leak valve according to the present invention. FIG. 2 is a block diagram further partially illustrating the block diagram of FIG. 1; FIG. 3 is an explanatory diagram showing a configuration of a rotation signal of a rotor. FIG. 4 is a time chart showing a process performed by a rotation speed detecting means with respect to a signal output of a rotation sensor. FIG. 5 is a flowchart showing a process of a rotation speed detecting unit. FIG. 6 is a flowchart showing a process of a rotation speed detecting unit. FIG. 7 is a flowchart illustrating processing of a rotation speed detecting unit. FIG. 8 is a block diagram showing another embodiment of the block diagram of FIG. 2; FIG. 9 is a block diagram partially showing another embodiment according to the present invention. [Description of Signs] 1 is a rotor, 2 is a CPU, 16 is rotation speed detecting means, 52
Is an air leak valve, 53 is a chamber, and 56 is an interlock means.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takahiro Fujimaki 1060 Takeda, Hitachinaka-shi, Ibaraki Pref. Hitachi Koki Co., Ltd. (56) References Japanese Utility Model Sho-61-139756 (JP, U) Japanese Utility Model Sho-62-95755 ( JP, U) JP-A 63-173351 (JP, U) JP-A 6-85047 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) B04B 15/08 B04B 13/00

Claims (1)

(57) [Claim 1] A rotor, a chamber for accommodating the rotor, an air leak valve for opening the chamber to atmospheric pressure, and a CPU for controlling opening and closing of the air leak valve
And an interlock means and a rotation speed detecting means, and the interlock means
The air leak valve is opened by the coincidence of the two signals of the valve opening signal output from the PU and the valve opening signal output from the rotation speed detection means, and the rotation speed detection means sets the rotation speed of the rotor to a predetermined low value. A centrifuge characterized by outputting a valve opening signal when the rotation speed is lower than the rotation speed.