JP3863285B2 - Cooling centrifuge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigerated centrifuge that can be used within the condition of 100V15A.
[0002]
[Prior art]
The cooling centrifuge is designed to keep the temperature in the rotor chamber containing the rotor above the set temperature so that the sample is not thermally denatured by frictional heat with the air generated when the rotor equipped with the sample to be centrifuged rotates at high speed. It is designed for the purpose of preventing the thermal denaturation of the sample by operating the refrigerator when it comes to cool the rotor chamber.
That is, the cooling centrifuge detects the temperature in the rotor chamber, compares the detected temperature in the rotor chamber with the set temperature, operates the refrigerator when the temperature in the rotor chamber exceeds the set temperature, A temperature control circuit for reducing the temperature in the rotor chamber is provided.
[0003]
In the conventional cooling centrifuge, when the rotation of the rotor is started, the control circuit of the refrigerator is also activated at the same time. When the rotor starts to rotate, the temperature starts to rise due to friction between the rotor and air, and when the temperature in the rotor chamber exceeds the set temperature, the refrigerator operates to cool the rotor chamber.
Usually, the temperature in the rotor chamber rises almost to room temperature by opening and closing the lid of the rotor chamber of the cooling centrifuge, and exceeds the set temperature (4 to 10 ° C.) that is normally set. For this reason, when the rotor receives a rotation command, the power supply of the refrigerator is also energized at the same time and starts cooling. That is, the refrigerator usually operates during acceleration of the rotor.
[0004]
On the other hand, high-speed performance is required for the cooling centrifuge. In addition, users (such as researchers in the biochemical field) desire to shorten the experiment time, and accordingly, the acceleration time (acceleration time until reaching the set rotation speed) is also required to be shortened. If rapid acceleration is performed, a motor that is a drive source is required to have a large output, and naturally, a motor drive current (acceleration current) during acceleration increases. This acceleration current increases approximately proportionally as the rotational speed increases. If the rotational speed of the rotor reaches the set rotational speed as time elapses, that is, if the acceleration period has passed and the steady rotational speed is reached, the motor drive current is about 1/2 to 1/3 of the maximum current value during acceleration. become. In particular, in recent years, high-speed motor technology has advanced, and an inverter-controlled induction motor has come to be used.
[0005]
Here, the power supply capacity to the cooling centrifuge is determined on the assumption that the refrigerator operates during acceleration of the rotor. In other words, if the refrigerator operates during acceleration of the rotor, a large current flows when the refrigerator is started, so this current is added to the acceleration current, and the power supply current at that time instantaneously becomes excessive. Assuming the maximum current in this case, the power supply capacity to the cooling centrifuge is determined as a value that can secure this maximum current.
[0006]
[Problems to be solved by the invention]
However, the power capacity required for the conventional cooling centrifuge exceeds 100V15A (capacity of a normal power outlet installed on a wall in Japan), and power supply equipment with the required power capacity is prepared. There must be. This power supply facility was prepared by the installer (user of the cooling centrifuge). This power supply equipment exceeding 100V15A must be installed specially and requires expensive equipment costs. In particular, a 200V power source and a three-phase power source are expensive when newly installed. Further, when the user tries to change the installation location of the cooling centrifuge, the power supply equipment must also be moved, which causes a problem that the installation location cannot be changed as intended.
[0007]
The present invention has been made to solve such a problem, and the object of the present invention is not to require a special power supply facility, but to have a high performance that can be used with a normal power supply capacity of 100V15A. It is to provide a cooling centrifuge.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, the present invention detects the temperature in the rotor chamber housing the rotor, compares the detected temperature in the rotor chamber with the set temperature, and the temperature in the rotor chamber exceeds the set temperature. In a cooling centrifuge equipped with a temperature control means that lowers the temperature in the rotor chamber when the refrigerator is operating, a rotor sensor that detects the rotor type and a cooling centrifuge that is used for each model A memory that stores a second set rotational speed that is lower than the first set rotational speed that is defined as a steady rotational speed after acceleration of the rotor determined for the rotor that can be driven, and the type of rotor detected by the rotor sensor Means for reading out the second set rotational speed from the memory, and during acceleration until the rotational speed of the rotor reaches the first set rotational speed, the second speed corresponding to the type of the rotor read from the memory The section from the set rotational speed to the first set rotational speed is obtained by providing a refrigerator actuation inhibiting means for inhibiting the operation of the refrigerator.
According to this invention, during acceleration until the rotational speed of the rotor reaches the first set rotational speed (steady rotational speed), the second set rotational speed (a predetermined lower speed than the steady rotational speed) according to the type of the rotor. In the section from the first rotation speed) to the first set rotation speed (steady rotation speed) , even if the temperature in the rotor chamber exceeds the set temperature, the refrigerator is not operated.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments.
〔principle〕
Prior to the description of the embodiments, the principle of the present invention will be described. In the present invention, as shown in FIG. 1, with respect to a set rotational speed (first set rotational speed) N1 that is a steady rotational speed after acceleration, a predetermined rotational speed (second speed) that is lower than the rotational speed N1. Set rotation speed) N2. The second set rotational speed N2 is the highest rotational speed at which the sum of the motor drive current and the refrigerator current required to obtain the rotational speed N2 falls within 15A. In FIG. 1, I indicates a change in motor drive current, and N indicates a change in the rotational speed of the rotor. It is known that the driving current of the refrigerator takes a constant consumption pattern regardless of the acceleration characteristics of the motor.
[0010]
Then, during the acceleration until the rotor rotational speed N reaches the first set rotational speed N1, the operation of the refrigerator is prohibited in the section from the first set rotational speed N1 to the second set rotational speed N2. That is, the operation of the refrigerator is permitted in a section from when the rotation of the rotor starts until the rotation speed N reaches the second rotation speed N2, and reaches the first rotation speed N1 from the second rotation speed N2. In the interval up to, the operation of the refrigerator is prohibited and the operation of the refrigerator is permitted after reaching the first rotation speed N1.
[0011]
As a result, even if the refrigerator is activated during the acceleration of the rotor, the power supply current does not exceed 15A and can be used with a normal power supply capacity of 100V15A. For this reason, a special power supply facility is not required, and the capital investment of the power supply facility becomes unnecessary. Moreover, since it can be used with a normal outlet of 100V15A, the user can move the cooling centrifuge to any place, and the installation location can be changed as desired. Further, since the current of the refrigerator can be controlled at the time of acceleration in which the maximum current flows, the acceleration characteristic of the motor can be strengthened by the amount of the current of the refrigerator.
[0012]
In FIG. 1, the second set rotational speed N2 varies depending on the air friction for each rotor, varies depending on the heat capacity due to the mass of the rotor, and varies depending on how long it takes to accelerate depending on the acceleration characteristics of the motor. . Therefore, the second set rotational speed N2 is experimentally obtained for every rotor that can be used for each cooling centrifuge model, and the second setting corresponding to the type of rotor accommodated in the rotor chamber is obtained. The rotation speed N2 is used. Thereby, the kind of rotor which can use a cooling centrifuge within the conditions of 100V15A can be increased, and a freedom degree expands.
[0013]
A method of not operating the refrigerator during the acceleration of the rotor is conceivable, but this method cannot suppress the temperature rise in the rotor chamber during the acceleration of the rotor. On the other hand, in the present invention, since the refrigerator can be operated up to the second set rotational speed N2 during acceleration, temperature rise in the rotor chamber can be suppressed.
[0014]
Embodiment
FIG. 2 is a block diagram of a cooling centrifuge showing an embodiment of the present invention. In the figure, 1 is a temperature sensor for detecting a temperature Tpv in a rotor chamber (not shown), 2 is a rotation sensor for detecting the rotational speed N of a rotor (not shown) accommodated in the rotor chamber, and 3 is a rotor chamber. Rotor sensors for detecting the type of rotor housed in the motor, 4, 5 and 6 are amplifiers, 7 is a temperature setting power supply, 8 is a diode, 9 is a refrigerator, 10 is a refrigerator control relay, and 11 is a refrigerator control relay. 10 relay contacts.
[0015]
Reference numeral 12 compares the rotor room temperature Tpv from the temperature sensor 1 input via the amplifier 4 with the set temperature Tsp from the temperature setting power source 7 input via the diode 8, and the rotor room temperature Tpv is A comparison circuit that sends a drive command to the refrigerator control relay 10 via the amplifier 6 when the set temperature Tsp is exceeded, 13 is a CPU, 14 is a ROM, 15 is a RAM, and 16 is an output interface.
[0016]
In this embodiment, the second set rotational speed N2 is experimentally obtained for all rotors that can be used for each model of the cooling centrifuge, and this is written in the ROM. Further, the first set rotational speed N1 is also written in the ROM 14 or RAM 15. Further, the CPU 13 inputs the rotor rotation speed N detected by the rotation sensor 2 and the type of rotor housed in the rotor chamber detected by the rotor sensor 3, and performs a predetermined processing operation while accessing the ROM 14 and RAM 15.
[0017]
FIG. 3 is a flowchart for explaining a characteristic operation in the cooling centrifuge.
[0018]
Now, assume that the cooling centrifuge is turned on. Then, the comparison circuit 12 compares the rotor room temperature Tpv with the set temperature Tsp (step 301), and if the rotor room temperature Tpv is higher than the set temperature Tsp (Tsp <Tpv), the refrigerator control relay is passed through the amplifier 6. A drive command is sent to 10. Here, the CPU 13 checks whether or not the rotor is rotating based on the rotation speed N of the rotor from the rotation sensor 2 (step 302). In this case, since the rotation of the rotor is not started just by turning on the power, it is determined that the rotor is not rotating (stopped).
[0019]
If the rotor is stopped at step 302, the CPU 13 sends a refrigerator drive permission command to the refrigerator control relay 10 via the output interface 16. Thereby, the drive command from the comparison circuit 12 is validated, and the refrigerator control relay 10 turns on the relay contact 11. Thereby, power is supplied to the refrigerator 9 and the refrigerator 9 is operated (step 303). When the rotor chamber is cooled by the operation of the refrigerator 9 and the rotor chamber temperature Tpv becomes equal to or lower than the set temperature Tsp (Tsp ≧ Tpv), the comparison circuit 12 sends the control circuit 10 to the refrigerator control relay 10 according to “NO” in step 301. A drive stop command is issued, the relay contact 11 is turned off, and the refrigerator 9 is stopped (step 304).
[0020]
As a result, preliminary cooling in the rotor chamber (cooling to a temperature below the temperature allowed by the sample and at which the sample does not freeze) is performed. The rotor is usually made of metal such as aluminum or stainless steel, and has a certain volume, so its heat capacity is large. Therefore, once cooled to the target temperature, even if heat is generated by air friction during a short period of time, such as the acceleration time until the rotor reaches the set rotational speed N1, the temperature becomes harmful to the sample. Until the rotor room temperature rises.
[0021]
However, if the lid of the rotor chamber is opened and closed during the preliminary cooling, the rotor chamber temperature may not be sufficiently cooled when the rotation of the rotor is started. In this case, during the acceleration of the rotor, the rotor room temperature Tpv exceeds the set temperature Tsp (Tsp <Tpv). A drive command may be sent from the comparison circuit 12 to the refrigerator control relay 10 via the amplifier 6. In this case, the CPU 13 confirms that the rotor is rotating (YES in step 302), confirms that the rotor is accelerating (NO in step 305), and then proceeds to step 306.
[0022]
In step 306, the CPU 13 reads out the second set rotation speed N2 of the model corresponding to the rotor type from the rotor sensor 3, and compares the second set rotation speed N2 with the actual rotation speed N of the rotor. . Here, if N ≦ N2, it is determined that it is not the refrigerator operation prohibition section, and a refrigerator drive permission command is sent to the refrigerator control relay 10 via the output interface 16. As a result, the drive command from the comparison circuit 12 is validated, and the refrigerator 9 is operated (step 307).
[0023]
On the other hand, if N> N2, it is determined that the vehicle is in the refrigerator operation inhibition section, and a refrigerator drive inhibition command is sent to the refrigerator control relay 10 via the output interface 16. Thereby, the drive command from the comparison circuit 12 is invalidated, and the refrigerator 9 does not operate.
[0024]
If the rotational speed N of the rotor reaches the first set rotational speed N1 and is a steady rotational speed, the operation of the refrigerator 9 is permitted regardless of the rotational speed of the rotor (steps 305 and 306). The motor drive current I at this time is small, and even if the refrigerator 9 is operated, the power supply current does not exceed 15A.
[0026]
In this embodiment, FIG. 1 shows a case where the acceleration characteristic of the rotor is slow. By slowly accelerating the rotor, the motor drive current I can be reduced, and the second set rotational speed N2 can be increased. The same applies to the case where the acceleration characteristic of the rotor is fast. In this case, the second set rotational speed N2 is lowered, and the refrigerator operation prohibited section is expanded.
[0027]
【The invention's effect】
As is apparent from the above description, according to the present invention, during the acceleration until the rotational speed of the rotor reaches the first set rotational speed (steady rotational speed), the second set rotational speed corresponding to the type of the rotor. The refrigerator may be operated even if the temperature in the rotor chamber exceeds the set temperature in a section from the number (a predetermined speed lower than the steady speed) to the first set speed (steady speed). No special power supply equipment is required by setting the second set rotation speed to the highest rotation speed within which the sum of the motor drive current and the refrigerator current required to obtain the rotation speed is within 15A. Instead, a high performance cooling centrifuge can be used with a normal power supply capacity of 100V15A.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the basic principle of the present invention.
FIG. 2 is a block diagram of a cooling centrifuge showing an embodiment of the present invention.
FIG. 3 is a flowchart for explaining a characteristic operation in the cooling centrifuge.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Temperature sensor, 2 ... Rotation sensor, 3 ... Rotor sensor, 4, 5, 6 ... Amplifier, 7 ... Power supply for temperature setting, 8 ... Diode, 9 ... Refrigerator, 10 ... Refrigerator control relay, 11 ... Relay contact , 12: comparison circuit, 13: CPU, 14: ROM, 15: RAM, 16: output interface.

Claims (3)

The temperature in the rotor chamber that houses the rotor is detected, the detected temperature in the rotor chamber is compared with the set temperature, and if the temperature in the rotor chamber exceeds the set temperature, the refrigerator is operated to detect the temperature in the rotor chamber. In a cooling centrifuge equipped with a temperature control means for lowering
A rotor sensor for detecting the type of the rotor;
A memory for storing a second set rotational speed lower than the first set rotational speed, which is determined as a steady rotational speed after acceleration of the rotor, determined for each of the cooling centrifuge models. When,
Means for reading out from the memory a second set rotational speed corresponding to the type of rotor detected by the rotor sensor;
During acceleration until the rotational speed of the rotor reaches the first set rotational speed , from the second set rotational speed corresponding to the type of the rotor read from the memory to the first set rotational speed for sections, the cooling centrifuge, characterized in that a refrigerator actuation inhibiting means for inhibiting the operation of the refrigerator. 2. The cooling centrifuge according to claim 1, wherein the second set rotational speed is such that a sum of a motor driving current and a current of the refrigerator required for obtaining the rotational speed is within a predetermined current value. A refrigerated centrifuge characterized by the highest rotational speed. 3. The cooling centrifuge according to claim 2, wherein the predetermined current value is 15A .

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