JPS6138678Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotor identification device for a centrifuge.

Some centrifugal separators have multiple rotors with different allowable rotational speeds that can be replaced depending on the purpose of use. When using such a centrifuge, it is common to accidentally set the speed setting value of the rotor drive motor to 5000 rpm or higher, even though the rotor is set for 5000 rpm. As a result, accidents such as damage to the rotor often occur.

Conventionally, an identification mark is attached to each of the rotors, and a photo sensor is provided to read the mark.If the identification signal output from this sensor does not match the speed setting value of the motor, the motor I was trying not to start it.

However, the above-mentioned optical rotor identification means has the disadvantage that the reliability decreases as the mark attached to the rotor and the sensor for reading it become contaminated with samples, etc. In some cases, accidents could not be prevented.

In view of this, the present invention aims to provide a rotor identification device for a centrifugal separator that can accurately identify the rotor without being affected by contamination by the above-mentioned samples, etc., and its features include: The rotor is identified using the rotational speed of the rotor driving motor.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 shows two types of rotors A, not shown.
1 shows an embodiment of the identification device according to the present invention applied to the case of identifying B. This device is comprised of a timer circuit 1, an identification circuit 2, and a circuit 3 for ANDing the identification signal output from the circuit 2 and the output signal of the timer circuit 1.

_The timer circuit 1 outputs _a signal when the time t determined by the resistor R ₁ and _the capacitor C ₁ has elapsed. A changeover switch is shown, and A ₁ and A ₂ are amplifiers. By the action of the differential capacitor _C2 connected to the output terminal of the amplifier _A1 , the timer circuit 1 outputs a signal for a short time when the set time t has elapsed.

On the other hand, the above identification circuit is a tachometer generator attached to a rotor drive motor (not shown).
TG and a capacitor C ₃ for smoothing the output signal of the generator TG rectified by the diode D.
, a variable resistor VR ₁ connected in parallel to the capacitor C ₃ , and a comparator COM ₁ that compares the output voltage of the resistor with a reference voltage V ₁ set by another variable resistor VR ₂ ; and a transistor _TR1 which receives the output signal of the comparator and energizes the relay _RY1 .

The circuit 3 also includes two transistors TR _A and TR _B , each receiving the output signal of the timer circuit 1 as a base and having their emitters selectively grounded via the contact r ₁ of the relay RY ₁ . , a relay RY _A energized by each transistor,
RY _B , and the respective collectors of the transistors TR _A and TR _B are connected to the normally open contacts r of the relays RY _A and RY _B.
It has a configuration in which it is grounded via _A and _rB . Note that SW ₂ is a switch that is interlocked with the changeover switch SW ₁ of the timer circuit 1.

Here, the reference voltage V ₁ set by the variable resistor VR ₂ of the identification circuit 2 will be explained. Now, when the rotors A and B are rotated separately by the rotor drive motor, the rotational speed of the motor changes as shown by curves a and b shown in FIG. 2, respectively. Therefore, the respective rotational speeds of the motor during the set time t of the timer circuit 1 are n _A and n _B , and at this time, the identification circuit 2
The variable ladder VR ₁ outputs voltages Vn _A and Vn _B, respectively. The above reference voltage V ₁ is equal to these voltages Vn _A and Vn _B
, it is set so that Vn _A < V ₁ < Vn _B.

The rotor identification device configured as described above operates as follows. That is, if we now consider the case where the rotor A is attached to the motor and rotated, the switch SW ₁ is turned on to the contact a side at the same time as the motor is started, and the timer circuit 1 starts timing. do. When the set time t of the timer circuit 1 has elapsed, the output voltage of the variable resistor _VR1 reaches the value _VnA . However, this voltage Vn _A is smaller than the reference voltage V ₁ and therefore at the time t the comparator
COM ₁ does not output any signal. In other words, the relay RY ₁ remains deenergized, and its contact r ₁ grounds the emitter of the transistor TR _A.

In such a state, the transistor TR _A
When the output signal of the timer circuit 1 is inputted to the base of the transistor TR A, the transistor TR _A becomes conductive and at the same time, the relay RY _A is energized. The relay RY _A is self-held via its contact r _A .

Note that after the set time t has passed, the variable resistor
When the output voltage of VR ₁ exceeds the above reference voltage V ₁ , comparator COM ₁ outputs a signal to energize relay RY ₁ ,
The contact _r1 thereby grounds the emitter of the transistor _TR2 , but since the timer circuit 1 is not outputting a signal at this point, the other relay _RYB is not activated.Then the other rotor Consider the case where B is rotated by the above motor. In this case, since the comparison input voltage Vn _B (Vn _B > V ₁ ) is input to the comparator COM ₁ at the time when the time t has elapsed, the comparator COM ₁ outputs a signal. As a result, relay RY ₁ is energized and its contact r ₁ grounds the emitter of transistor TR _B. At this time, since the output signal of the timer circuit 1 is applied to the base of the transistor TR _B , the transistor becomes conductive, thereby energizing the relay RY _B. And this relay RY _B maintains itself through its contact r _B.

As described above, according to the identification device according to the embodiment described above, it is possible to identify whether the A rotor or the B rotor is used depending on the operating states of the relays RY _A and RY _B.

Next, an application example of this identification device will be explained. FIG. 3 shows a safety device that operates to cut off the power supply to the rotor drive motor when the rotation speed of the A rotor or B rotor exceeds the permissible rotation speed using the identification result of the identification device. shows. In the figure, COM ₂ has one input end connected to the variable resistor VR ₁ , and the other input end connected to each relay via the normally open contacts r' _A and r' _B of the relays RY _A and RY _B. A comparator connected to a reference voltage source V _A V _B is shown.
Therefore, the values of the reference voltage sources V _A and V _B are as follows:
When the motor is rotated up to (permissible rotational speed), each voltage value is set to be output from the variable resistor _VR1 .

RY ₂ indicates a relay energized by a transistor TR ₂ connected to the output of the comparator COM ₂ , whose contact r ₂ is connected to the rotor drive motor M
It is inserted into the self-holding line of the drive circuit.

Now, consider a case where the rotation speed setting value of the signal motor M by a speed control means (not shown) is set to be higher than the allowable rotation speed of the A rotor. In such a case, when the A rotor is connected to the motor M and is used, the relay RY _A of the identification device is activated when t time has elapsed after the motor is started, and thereby one of the comparators COM ₂ is activated. The reference voltage V _A for the A rotor is connected to the input end via the contact r' _A of the closed relay RY _A. The rotational speed of the rotor A (motor M) thus increases further, but at the same time as the rotor reaches the permissible rotational speed, the comparator COM ₂ outputs a signal and the relay RY ₂ is energized. As a result, the self-holding of the relay _RY3 of the motor drive circuit is released, and the motor M is disconnected from the power supply, thereby preventing the A rotor from rotating beyond the permissible number of rotations.

Similarly, even if the speed setting dial of the speed control means is accidentally set to a value higher than the allowable rotation speed of the B rotor when the B rotor is used, the power supply to the motor M can be cut off.

Note that speed control means for the motor M is provided in the motor drive circuit shown in FIG.

Furthermore, it is also possible to display the centrifugal acceleration rω ² (r: rotor radius, ω: angular velocity) of the rotors A and B by using the identification results of the identification device. That is, as shown in Fig. 4, when inputting the output signal of the tachogenerator TG to the amplifier _A3 to display the centrifugal acceleration on the meter ME, the gain of the amplifier _A3 is set to the relay.
If you change it using the contacts r″ _A and r″ _B of RY _A and RY _B , you can automatically display the centrifugal acceleration on the meter ME when using either rotor. . Note that the meter ME has a scale that displays √ω as ^rω2 , and the signal amplifier A ₃ sets a coefficient √ to be multiplied by the ω component output from the tachogenerator TG.

The above embodiment is configured to identify two types of rotors, but the present invention provides (number of rotors to be identified - 1) comparators COM ₁ shown in FIG. Reference voltage for the device
By setting V ₁ , V ₂ , ... in the manner described using FIG. 2, and processing the comparison results of these comparators and the output signal of timer circuit 1 in a logic circuit, 2 It can also be applied to the case of identifying rotors of more than one species.

As described above, the rotor identification device for a centrifuge according to the present invention identifies each rotor by detecting the rotational speed of the rotor drive motor, so it is different from the case where the optical identification means is used. This allows for more accurate identification, and its practicality is high.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a rotor identification device according to the present invention, and FIG. 2 is a graph showing changes in motor rotation speed for each rotor. Figure 3 is a circuit diagram showing an example of a safety device that uses the comparison results of the devices shown in Figure 1, and Figure 4 shows a centrifugal acceleration display circuit that uses the comparison results of the devices shown in Figure 1. . 1... Timer, 2... Identification circuit, 3... AND circuit, TG... Tachozi generator, A ₁ to _{A 3} ...
...Amplifier, RY _A , RY _B , RY ₁ ~ RY ₃ ... Relay,
COM ₁ , COM ₂ ... Comparator, TR ₁ , TR ₂ , TR _A ,
TR _B ...Transistor, _R1 ...Resistor, _C1 to _C3
...Capacitor, SW ₁ , SW ₂ ...Switch,
VR ₁ , VR ₂ ...Variable resistor, M...Motor.

Claims (1)

[Scope of utility model registration request] In a centrifugal separator configured to use multiple types of rotors interchangeably, a means for detecting the speed of a rotor driving motor, and a means for detecting the speed of a rotor driving motor, and for outputting a signal after timing a certain time t by starting the motor at the same time. A timer and a value Vn _A corresponding to each output signal value of the speed detection means when each rotor is rotated by the motor for a time t.
Vn _A <V ₁ < preset based on Vn _B ,...
Vn _B , Vn _B < V ₂ < Vn _C ,... Reference values V ₁ , V ₂ ,...
means for comparing the respective reference values V ₁ , V ₂ , . . . with the output signal value of the speed detection means, and logical product of the comparison result of the comparison means and the output signal of the timer. A rotor identification device for a centrifuge, comprising means.