JPH01208685A - Refrigerating device - Google Patents

Abstract

PURPOSE:To manufacture a refrigerating device, having a small thermal load as well as two different temperature levels, simply, by a method wherein the heat of a cold storage chamber, having a high preservation temperature, is exchanged between the heat of the evaporator of a refrigerating cycle and the heat of a refrigerating chamber is exchanged between the heat of a low-temperature surface of a Peltier element to cool it while the heat of the high-temperature surface of the same element is exchanged between the heat of the evaporator of the refrigerating cycle. CONSTITUTION:The low-temperature surface 9a of a Peltier element 9 is provided at the side of a refrigerating chamber 5a, the high-temperature surface 9b of the element is provided at the side of an evaporator 6, the refrigerating chamber 5a and a cold storage chamber 5b are provided with temperature detectors 10a, 10b while a controller 11, controlling the operations of a compressor 1 as well as the Peltier element 9 in accordance with values obtained by the temperature detectors 10a, 10b, is provided. The cold storage chamber 5b is cooled by the heat exchange of the evaporator 6 while the refrigerating chamber 5a is cooled by producing the flow of heat from the refrigerating chamber 5a to the Peltier element low-temperature surface 9a and the same from the Peltier element high-temperature surface 9b to the evaporator 6. This device is suitable for the control of two temperatures, such as -20 deg.C and 4 deg.C for example, of a reservation chamber for the automatic processing device of a living organism such as DNA or the like.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides automatic processing of biological samples such as DNA,
The present invention relates to a refrigeration device suitable for use in an apparatus having a function of cooling storage chambers at two different temperature levels.

[Conventional technology]

Conventional refrigeration devices for cooling storage chambers at two different temperature levels include those that use a refrigeration cycle to configure a refrigerator-freezer (Japanese Patent Laid-Open Nos. 55-14417 and 1983-1983).
15'7776).

[Problem to be solved by the invention]

For example, an automatic biological sample processing device such as D N'A has a
A refrigeration system is required to control the temperature of the storage chamber at two different temperature levels, -20°C and 4°C. In other words, the temperature is controlled in two parts: a freezing room at a temperature of -20°C to store reagents such as enzymes used in the reaction, and a refrigerator room at a level of 4°C to store samples before and after the reaction without freezing. Part 1
, 5 m D, IQ'P that can store visual sample containers
It is sufficient to have a volume of A degree. These refrigeration loads are about 10 to 20 W for both the refrigerator and freezer compartments because their volumes are as small as IQ. A household refrigerator-freezer is conventionally known as a device equipped with such a freezer compartment and a refrigerator compartment.
It is large from 0ff to several 100Q, so the refrigeration capacity is also 10
It is large, about 0W or more. Therefore, the size of this refrigerator-freezer is too large to be used as it is in a freezing device for an automatic DNA processing device. Furthermore, although it is possible to make a refrigeration device for an automatic DNA processing device using the compressor used in such household refrigerator-freezers, the refrigeration capacity is excessive, so it frequently starts and stops. This not only makes temperature control difficult.

There are also problems with reliability. It is also possible to develop a compressor that is significantly smaller than the conventional specifications and use it to configure the same refrigeration system as the conventional method, but in this case, the cost burden of developing a new compressor would be reduced. Due to the large size and the fact that the market for automatic biological sample processing equipment mentioned above is smaller than that of conventional home-use refrigerators and refrigerators, cost reductions cannot be expected through mass production. I can't.

The purpose of the present invention is to solve the above problems, reduce heat load,
The object of the present invention is to provide a refrigeration device suitable for controlling the temperature of a storage chamber having two different temperature levels.

[Means for solving the problem] The above purpose is to cool the refrigerator compartment where the storage temperature is high by exchanging heat with the evaporator of the freezing cycle, and to exchange heat with the low temperature surface of the Peltier element in the freezing compartment where the storage temperature is low. This is accomplished by configuring the refrigeration cycle evaporator to cool and exchange heat with the hot side of the Vertier element and the refrigeration cycle evaporator.

[Effect]

The operation of the refrigeration system according to the present invention is as follows.

The refrigerator compartment, where the storage temperature is high, is cooled by heat exchange with the evaporator of the freezing cycle, and the freezing compartment, where the storage temperature is low, is cooled by heat flow from the freezing compartment to the low temperature side of the Peltier element, and from the high temperature side of the Peltier element to the refrigeration cycle evaporator. It is cooled by fermenting it.

〔Example〕

The configuration of an embodiment of a refrigeration system according to the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an embodiment of a refrigeration system according to the present invention. In this embodiment, compressor 1. Condenser 2.
Expansion mechanism using capillary tube etc. 3. A refrigeration system comprising a freezing chamber 5a for storing sample containers at a temperature level of -20°C, a refrigerating chamber 5b for storing sample containers at a temperature level of 4° C., and an evaporator 6 for cooling the freezing/refrigerating chambers 5a and 5b, The Beltier element 9 is provided with its low temperature surface 9a facing the freezer compartment 5a side and its high temperature surface 9b facing the evaporator 6 side,
and a temperature sensor 10a in the freezer compartment 5a and the refrigerator compartment 5b,
10b, and a controller 11 for controlling the operation of the compressor 1 and the Vertier element 9 according to the values of the temperature detectors 10a and 10b. That is, the refrigerator compartment 5b
The freezing chamber 5a is cooled by heat exchange with the evaporator 6, and by generating a heat flow from the freezing chamber 5a to the Peltier element low temperature surface 9a and the Peltier element high temperature surface 9b to the evaporator 6.

FIG. 2 shows an operation flowchart of the controller 11. The freezer compartment temperature detected by the temperature sensor 10a is compared with Ta, Ta. The first set value is compared with Tax, Ta. The second set value is Ta2 (T a x < Ta
2) Tbz, Tb are the first set values for comparing the refrigerator room temperature detected by the temperature sensor 10b with Tb, Tb.
The second setting value to be compared with I” b z(T b 1<
T b z). First, the freezer compartment temperature Ta is compared with the first set value Tax, and if Ta is higher than Ta 1, current is continued to flow through the Vertier element 9, and Ta is T a i
If it becomes lower than that, the current of the Bertier element 9 is stopped. Freezer room temperature T at which current to Peltier cord 9 is stopped
a increases, but in order to avoid frequent on/off repetitions of the Bertier element 9, the freezer compartment temperature Ta is set at the first setting (the second set value Ta higher than p'j'r a 1).
In comparison with z, when Ta becomes higher than T a z, current begins to flow through the Bertier element 9. Next, the temperature of the refrigerator compartment T
Similarly, for b, Tb was compared with the first set value Tb, and if Tb was higher than Tb1, the compressor 1 was driven to continue operating the refrigeration cycle, and Tb became lower than Tb1. If so, the compressor 1 is stopped. When the compressor 1 is stopped, the refrigerator compartment temperature Tb rises, but in order to avoid frequent turning on and off of the compressor 1, the refrigerator compartment temperature Tb is increased.
b to a second set value T higher than the first set value T b s
Compared with b2, when Tb becomes higher than Tbx, the compressor 1 is driven to cool the refrigerator compartment 5b.

In the refrigeration system according to the present invention, the relationship between the heat load and the required capacity of the equipment used when controlling the temperature of the freezer compartment and refrigerator compartment, each with a refrigeration load of 20W, is shown, and the reason why refrigeration operation with a capacity of 10 to 20W can be easily realized. state. The temperature in the freezer compartment is -20°C, and the temperature in the refrigerator compartment is 4°C. The heat load on the refrigeration cycle evaporator is the sum of the heat entering the refrigerator, the Peltier element refrigeration capacity, and the Peltier element current input. The required refrigerating capacity of the Beltier element is 20W, since it is equal to the heat entering the freezer compartment.

Assuming that the high-temperature surface temperature of the Peltier device is 0° C. and the low-temperature surface temperature is −25° C., the current input to the Peltier device to achieve these temperature conditions is about 40 W. Furthermore, since the heat entering the refrigerator compartment is also 20W, the heat load on the refrigeration cycle evaporator is estimated to be 80W. If the refrigeration capacity is set to twice the load in order to provide some margin for the load, the refrigeration cycle will have a refrigeration capacity of about 160W, but a compressor that meets this condition is not suitable for home-use refrigerators. The compressor used is mass-produced, and it can be easily achieved by using it. From the above studies, it was found that the configuration of the present invention
It can be seen that refrigeration operation with a capacity of 20W can be easily achieved.

The configuration of a second embodiment of the refrigeration system according to the present invention will be described with reference to FIGS. 3 and 4. FIG. 4 is a plan configuration diagram of this embodiment, and FIG.
It is a cross-sectional view of part b. In this embodiment, compressor 1. Condenser 2. Expansion mechanism using capillary tube etc. 3. A freezing device comprising a freezer compartment 58g for storing the sample container 4 at a temperature level of -20°C, a refrigerator compartment 5b for storing the sample container 4 at a temperature level of 4°C, and an evaporator 6 for cooling the freezing/refrigerating compartment 5. Insulating walls 7a, 7b, 7c, 7d, 7e that insulate the freezer/refrigerator compartment 5, sample containers 4 made of metal materials such as aluminum with low specific heat and excellent thermal conductivity.
．． Evaporator 5. A temperature holding member 8a that contacts the Beltier element 9 and performs heat exchange.

8b, a Vertier element 9 is provided with its low temperature surface 9a facing the freezer compartment 5a side and its high temperature surface 9b facing the evaporator 6 side, and temperature sensors 10a, 10b are installed in the freezing compartment 5a and refrigerator compartment 5b.
Furthermore, a controller 11 is provided to control the operation of the compressor 1 and the Bertier element 9 according to the value of the temperature sensor 10.

Note that the control flowchart of the refrigeration system of this embodiment is the same as that described in FIG.

In this embodiment, a method is adopted in which the sample container 4 is cooled by bringing it into direct contact with the temperature holding member 8.
Compared to the method of cooling air, this method has the advantage that the sample container 4 can be cooled to a predetermined temperature in a short time, and the refrigeration load is also reduced. Furthermore, since a material with high thermal conductivity and low specific heat is used for the temperature holding member 8, the cooling device has an excellent cool-down characteristic. In addition, the insulation wall 7
c covers the upper parts of the temperature maintaining members 8a and 8b to prevent heat intrusion from the outside and frost adhesion.
It has the advantage that there is no need to install an insulating door on the top of the device.

Furthermore, in this embodiment, the freezer compartment temperature Ta is the set value Ta
There is also an advantage that temperature control is easy even when the refrigerator compartment temperature Tb is lower than the set value T b 1. In this case, the compressor 1 is stopped and current continues to flow through the Vertier element 9. In this embodiment, the Peltier element is made of a metal material with excellent thermal conductivity and extends from the high temperature surface 9b to the refrigerator compartment 5b. Since the structure is configured such that heat flows through the temperature holding member 8b, the temperature of the refrigerator compartment 5b can be raised while the cooling action of the freezer compartment 5a is progressing, and it is possible to prevent the sample from freezing due to excessive cooling in the refrigerator compartment 5b. .

Finally, FIG. 5 shows a sectional view of the freezer/refrigerator compartment 5 in the third embodiment. This causes the Beltier element 9 to have a high temperature surface 9b.
is provided on the refrigerator compartment 5b side, with its low-temperature surface 9a facing the freezing compartment 5a side, and the method shown in the flowchart of FIG. 2 is adopted as a control method. In this embodiment, the heat transfer from the Peltier element high temperature surface 9b to the refrigerator compartment 5b is performed more smoothly, so that the freezer compartment temperature Ta is equal to the set value Tax.
There is an advantage that temperature control becomes easier when the refrigerator compartment temperature Tb is lower than the set value Tb1. That is, the compressor 1 is stopped, current continues to flow through the Peltier element 9, heat is passed from the Peltier element high temperature surface 9b to the refrigerator compartment 5b, and the refrigerator compartment 5 is cooled while cooling the freezer compartment 5a.
By raising the temperature of refrigeration chamber 5b, it is possible to more easily prevent the sample from freezing due to excessive cooling in the refrigerator compartment 5b.

〔Effect of the invention〕

As explained above, in the present invention, a storage chamber with a small heat load and two different temperature levels can be provided with a simple configuration that does not increase the price, and also has excellent temperature controllability and cool-down characteristics. We can provide refrigeration equipment.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a first embodiment of a refrigeration system according to the present invention;
FIG. 2 is a flowchart showing the operation of the controller, FIG. 4 is a plan configuration diagram of a second embodiment of the refrigeration system according to the present invention,
FIG. 3 is a cross-sectional view of the refrigerator/freezer compartment, and FIG. 5 is a cross-sectional view of the third embodiment. DESCRIPTION OF SYMBOLS 1... Compressor, 4... Sample container, 5a... Freezing room, 5b... Refrigerator room, 6... Evaporator, 7... Heat insulation wall, 8... Temperature holding member, 9... Peltier element, 10
...Temperature detector. 11... Controller.

Claims (1)

[Claims] 1. In a refrigeration system consisting of a refrigeration cycle consisting of a compressor, a condenser, an expansion mechanism, and an evaporator, and a storage chamber with two temperature levels, a freezing chamber in which the storage temperature in the storage chamber is set low; The Peltier element is cooled by the low temperature side, and the high temperature side of the Peltier element and the refrigerator compartment in which the storage temperature is set high are configured to cool both by exchanging heat with the evaporator of the refrigeration cycle. A refrigeration device characterized by: 2. The temperature maintaining members of the refrigerator compartment and the freezing compartment are each made of a solid material with low specific heat and excellent thermal conductivity, and the temperature maintaining member of the freezing compartment and the low temperature surface of the Peltier element are brought into contact with each other, and the temperature of the refrigerator compartment is The refrigeration system according to claim 1, characterized in that the holding member, the evaporator, and the high-temperature surface of the Peltier element are brought into contact with each other.