JP7469181B2 - Heat Pipe Thermostat - Google Patents

Description

The present invention relates to a heat pipe thermostatic chamber.

There is a known technology that uses a Peltier element in a heat pipe to improve cooling performance. The Peltier element itself dissipates a large amount of heat, so it needs to be cooled. For example, Patent Document 1 discloses a technology that uses a blower fan to cool the Peltier element.

JP 2008-203211 A

However, there are cases where cooling of the Peltier element by a blower fan as disclosed in Patent Document 1 is insufficient. The present invention has been made to address such insufficient cases, and aims to provide a heat pipe thermostatic bath with excellent cooling efficiency for the Peltier element.

The heat pipe thermostatic bath according to the present invention comprises:
a first heat pipe and a second heat pipe provided between the inside and the outside of the thermostatic chamber, through which a refrigerant circulates;
a heat dissipation unit that dissipates heat from the first and second heat pipes outside the thermostatic chamber;
a heat exchanger provided in the thermostatic chamber and configured to transfer heat from within the thermostatic chamber to the first and second heat pipes;
a heat absorbing unit that is provided outside the thermostatic chamber between the heat exchange unit and the heat dissipation unit and absorbs heat from the first and second heat pipes using a Peltier element;
a third heat pipe provided across the heat dissipation portion and the heat absorption portion and configured to transfer heat dissipated from the Peltier element to the heat dissipation portion;
the third heat pipe is disposed between the first and second heat pipes;
the Peltier element is a pair of Peltier elements provided between the third heat pipe and the first and second heat pipes in the heat absorption portion,
the heat absorbing surfaces of the pair of Peltier elements are provided so as to be in contact with the first and second heat pipes,
each of the heat dissipation surfaces of the pair of Peltier elements is provided so as to be in contact with the third heat pipe;
The heat radiated from the heat radiating surfaces of the pair of Peltier elements is transferred to the heat radiating portion via the third heat pipe.

In the heat pipe thermostatic bath according to the present invention, a third heat pipe is disposed between the first and second heat pipes, and a pair of Peltier elements is disposed between the third heat pipe and the first and second heat pipes in the heat absorption section. Each of the heat dissipation surfaces of the pair of Peltier elements is arranged so as to be in contact with the third heat pipe, and the heat dissipated from the heat dissipation surfaces of the pair of Peltier elements is transferred to the heat dissipation section via the third heat pipe. Therefore, the cooling efficiency of the Peltier elements is excellent.

The present invention provides a heat pipe thermostatic bath with excellent cooling efficiency for Peltier elements.

FIG. 2 is a perspective view of a heat pipe constant temperature bath according to the first embodiment. 1 is a schematic cross-sectional view showing a configuration of a heat pipe constant temperature bath according to a first embodiment.

Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. In addition, the following descriptions and drawings have been simplified as appropriate for clarity of explanation.

First Embodiment
Hereinafter, a heat pipe thermostatic bath according to a first embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig. 1 is a perspective view of the heat pipe thermostatic bath according to the first embodiment. Fig. 2 is a schematic cross-sectional view showing the configuration of the heat pipe thermostatic bath according to the first embodiment. It should be noted that the right-handed xyz orthogonal coordinate system shown in Figs. 1 and 2 is, of course, for the convenience of explaining the positional relationship of the components. Usually, the positive direction of the z axis is vertically upward, and the xy plane is a horizontal plane, which is common to all the drawings.

As shown in FIG. 1, the heat pipe thermostatic chamber 1 according to the first embodiment includes heat pipes 11-13, a heat dissipation section 20, a heat absorption section 30, and a heat exchange section 40. The heat pipe thermostatic chamber 1 is used, for example, for testing and analysis at a constant temperature.

The heat pipe 11 (first heat pipe) and the heat pipe 12 (second heat pipe) are metal pipes such as copper pipes through which a refrigerant circulates. However, depending on the target thermostatic bath temperature, energy saving performance, and allowable dimensions, the material constituting the heat pipes 11 and 12 may be other metals with high thermal conductivity such as aluminum, iron, and stainless steel.
1, the heat pipes 11 and 12 have a loop structure in which the refrigerant circulates between a heat exchanger 40 provided inside the thermostatic chamber and a heat radiator 20 and a heat absorber 30 provided outside the thermostatic chamber. The refrigerant heated in the heat exchanger 40 is sequentially cooled in the heat radiator 20 and the heat absorber 30. The heat pipes 11 and 12 are provided approximately parallel to each other around the entire circumference.

The configuration of the heat pipes 11 and 12 shown in FIG. 1 will be described in detail below.
As shown in FIG. 1 , in the thermostatic chamber, the heat pipes 11 and 12 are arranged in parallel to each other in the x-axis direction, branched, and extended in the y-axis direction, penetrating the inside of the heat exchanger 40 .
The heat pipes 11, 12 extending in the x-axis direction along the y-axis negative end of the heat exchange unit 40 are bent in an L-shape at the x-axis negative end and extend in the z-axis positive direction along the y-axis negative end faces of the heat dissipation unit 20 and the heat absorption unit 30. Here, the x-axis positive ends of the heat pipes 11, 12 extending in the x-axis direction along the y-axis negative end of the heat exchange unit 40 are closed.
Furthermore, heat pipes 11 and 12 are bent into an L shape at their ends on the z-axis positive side, and extend in the y-axis positive direction along the side surface of heat dissipation portion 20 on the z-axis positive side.

1, the heat pipes 11 and 12 extending in the x-axis direction along the y-axis positive end of the heat exchange unit 40 are bent in a U-shape at the x-axis negative end and extend in the y-axis negative direction along the z-axis negative side surface of the heat absorption unit 30. Here, the x-axis positive ends of the heat pipes 11 and 12 extending in the x-axis direction along the y-axis positive end of the heat exchange unit 40 are closed.
The heat pipes 11, 12 extending in the y-axis direction along the z-axis positive side surface of the heat dissipation unit 20 and the z-axis negative side surface of the heat absorption unit 30 are branched in parallel to the y-axis direction, extend in the z-axis direction, and penetrate the insides of the heat dissipation unit 20 and the heat absorption unit 30. The y-axis positive side ends of the heat pipes 11, 12 extending in the y-axis direction along the z-axis positive side surface of the heat dissipation unit 20 are closed. In addition, the y-axis negative side ends of the heat pipes 11, 12 extending in the y-axis direction along the z-axis negative side surface of the heat absorption unit 30 are closed.

Like heat pipes 11 and 12, heat pipe 13 (third heat pipe) is also a metal pipe such as a copper pipe through which a refrigerant circulates. Heat pipe 13 extends in the y-axis direction along the z-axis positive side surface of heat dissipation section 20 and the z-axis negative side surface of heat absorption section 30. Heat pipe 13 branches in parallel to the y-axis direction and extends in the z-axis direction, penetrating the inside of heat dissipation section 20 and heat absorption section 30.

As shown in FIG. 2, the heat pipe 13 extends in the z-axis direction across the heat dissipation section 20 and the heat absorption section 30, and is disposed between the heat pipes 11 and 12. Note that FIG. 2 is not a cross section of FIG. 1 cut along a specific plane, but a schematic cross section for showing the internal structure of the heat dissipation section 20 and the heat absorption section 30. Here, as shown in FIG. 1, the y-axis positive side end and the y-axis negative side end of the heat pipe 13 that extends along the y-axis direction along the z-axis positive side side of the heat dissipation section 20 are closed. In addition, the y-axis positive side end and the y-axis negative side end of the heat pipe 13 that extends along the y-axis direction along the z-axis negative side of the heat absorption section 30 are closed.

In the heat absorption section 30 outside the thermostatic chamber, the Peltier element 50 is disposed between the heat pipe 11 and the heat pipe 13, and between the heat pipe 12 and the heat pipe 13. The heat pipe 13 is used to transfer the heat emitted from the Peltier element 50 in the heat absorption section 30 to the heat dissipation section 20. In other words, the heat pipe 13 is used to cool the Peltier element 50. By adopting a three-layer structure consisting of three heat pipes, heat pipes 11-13, the cooling of the Peltier element 50 can be made more efficient. The mechanism for making the cooling of the Peltier element 50 more efficient will be described later with reference to FIG. 2. Furthermore, by adopting a structure in which a pair of Peltier elements 50 is cooled by one heat pipe 13, the number of heat pipes can be reduced by one, and the size can be reduced, compared to the case in which a pair of Peltier elements 50 is cooled by two separate heat pipes.

In the example shown in FIG. 2, the heat pipe thermostatic bath 1 has a three-layer structure of heat pipes 11-13. The heat pipe thermostatic bath 1 may have a five-layer structure in which another Peltier element and a heat pipe dedicated to cooling the Peltier element are provided on the outside of the heat pipes 11 and 12. In this case, power consumption increases, but the cooling capacity can be improved. In addition to the three-layer and five-layer structures, the heat pipe thermostatic bath 1 may have a multi-layer structure in which the layers provided with Peltier elements and heat pipes dedicated to cooling the Peltier element are arbitrarily increased.

The heat dissipation unit 20 is a heat exchanger provided outside the thermostatic chamber to dissipate heat from the heat pipes 11-13. In the example shown in FIG. 1, the heat dissipation unit 20 has a rectangular parallelepiped shape with its main surface parallel to the yz plane and extended in the z-axis direction. It is important to increase the cooling capacity of the heat dissipation unit 20. For this reason, the heat dissipation unit 20 may use porous copper metal fins, which have a heat transport capacity six times or more compared to normal metal fins made of copper or aluminum. This can increase the cooling efficiency of the heat pipes 11-13 in the heat dissipation unit 20. Since porous copper metal has a higher cooling efficiency than copper or aluminum metal fins, the amount of fins used can be reduced compared to when copper or aluminum metal fins are used. This allows the heat dissipation unit to be made smaller. In addition, the porosity of the fins also leads to weight reduction. Naturally, copper or aluminum metal fins can also be used as cooling fins.

The heat absorption unit 30 is a heat exchanger provided outside the thermostatic chamber to dissipate heat from the heat pipes 11-13 and the Peltier element 50. The Peltier element 50 is provided inside the heat absorption unit 30, and absorbs heat from the heat pipes 11 and 12. In the example shown in FIG. 1, the heat absorption unit 30 has a rectangular parallelepiped shape with its main surface parallel to the yz plane and extending in the z-axis direction. The heat absorption unit 30 has a configuration in which a large number of fins made of aluminum, a metal with high thermal conductivity, are stacked. Note that the material used for the heat absorption unit 30 may be changed from aluminum to other metals with high thermal conductivity, such as copper, iron, and stainless steel. The detailed configuration of the heat absorption unit 30 will be described later with reference to FIG. 2.

The heat exchange unit 40 is a heat exchanger that is provided in the thermostatic chamber and maintains a constant temperature in the thermostatic chamber. In the example shown in FIG. 1, the heat exchange unit 40 has a rectangular parallelepiped shape with its main surface parallel to the xy plane and extending in the y-axis direction. The heat exchange unit 40 has a configuration in which a large number of fins made of aluminum, a metal with high thermal conductivity, are stacked. Note that the material used for the heat exchange unit 40 may be changed from aluminum to other metals with high thermal conductivity, such as copper, iron, or stainless steel.

As described above, the heat pipes 11 and 12 that are branched and arranged in parallel in the x-axis direction penetrate the inside of the heat exchanger 40. This increases the heat exchange area where the heat exchanger 40 and the heat pipes 11 and 12 are in contact, increasing the efficiency of heat exchange. The heat pipes 11 and 12 that penetrate the heat exchanger 40 may be single pipes. In addition, in FIG. 1, the heat exchanger 40 is provided with a rectangular parallelepiped heat exchanger through which the heat pipe 11 penetrates, and a rectangular parallelepiped heat exchanger through which the heat pipe 12 penetrates, which are separately provided so that they are parallel to the xy plane. The heat exchanger 40 may be provided integrally instead of separately.

Similarly, the heat pipes 11-13 that are branched and aligned in the y-axis direction penetrate the heat dissipation section 20 and the heat absorption section 30. This increases the heat exchange area between the heat pipes 11-13 and the heat dissipation section 20, and between the heat pipes 11-13 and the heat absorption section 30, respectively, and therefore increases the efficiency of heat exchange. Better heat exchange efficiency means better cooling efficiency. The heat pipes 11-13 that penetrate the heat dissipation section 20 and the heat absorption section 30 may be single pipes.

In addition, in FIG. 1, the heat dissipation unit 20 is made up of a rectangular heat exchanger through which the heat pipe 11 passes, a rectangular heat exchanger through which the heat pipe 13 passes, and a rectangular heat exchanger through which the heat pipe 12 passes, which are provided separately on a flat surface. The heat exchangers are not bonded to each other, and have spaces between them. This increases the surface area exposed to the outside air outside the thermostatic chamber, improving the cooling efficiency. The heat dissipation unit 20 may be provided as an integrated unit rather than separately.

Similarly, for the heat absorption unit 30, a rectangular parallelepiped heat exchanger through which the heat pipe 11 passes, a rectangular parallelepiped heat exchanger through which the heat pipe 13 passes, and a rectangular parallelepiped heat exchanger through which the heat pipe 12 passes are provided separately and parallel to each other. Note that the heat absorption unit 30 may be provided integrally instead of separately.

In addition, heat pipes 11 and 12 can be designed with one circulation path each, so refrigerant injection and vacuuming can be performed at the same time. Furthermore, the structure with this circulation path (loop structure) makes it possible to unidirectionalize the flow path, including the state transition between liquid and gas phases, thereby reducing pressure loss.

Next, the structure of the heat absorption unit 30 will be described in detail with reference to FIG. 2. FIG. 2 is a schematic cross-sectional view showing the configuration of the heat pipe thermostatic bath 1 according to the first embodiment. As shown in FIG. 2, in the heat absorption unit 30, a pair of Peltier elements 50 having a rectangular parallelepiped shape with their main surfaces parallel to the yz plane are arranged between the heat pipes 11 and 13 and between the heat pipes 12 and 13.

The surface of the Peltier element 50 facing the heat pipe 11 is the heat absorption surface 51 that absorbs the heat of the heat pipe 11. Similarly, the surface of the Peltier element 50 facing the heat pipe 12 is the heat absorption surface 52 that absorbs the heat of the heat pipe 12. That is, each of the heat absorption surfaces 51, 52 of the pair of Peltier elements 50 is provided so as to be in contact with the heat pipes 11, 12, respectively.

On the other hand, the surface of the Peltier element 50 facing the heat pipe 13 is the heat dissipation surface 53 that dissipates heat from the heat pipe 11. Similarly, the surface of the Peltier element 50 facing the heat pipe 13 is the heat dissipation surface 54 that dissipates heat from the heat pipe 12. In other words, each of the heat dissipation surfaces 53, 54 of the pair of Peltier elements 50 is provided so as to be in contact with the heat pipe 13.

With this configuration, the heat absorption surfaces 51 and 52 of the Peltier element 50 absorb the heat from the heat pipes 11 and 12, and the heat dissipation surfaces 53 and 54 of the Peltier element 50 dissipate the heat to the heat pipe 13. The released heat is transferred to the heat dissipation section 20 via the heat pipe 13, thereby cooling the Peltier element 50.

Here, the mechanism of constant temperature control of the heat pipe constant temperature bath 1 and the mechanism for increasing the cooling efficiency of the Peltier element 50 will be explained using Figures 1 and 2. In the heat pipe constant temperature bath 1 of the present invention, a refrigerant is sealed in the heat pipes 11-13. The refrigerant in the heat pipes 11 and 12, which have a loop structure, circulates between the inside and outside of the constant temperature bath.

Considering the environmental friendliness, a non-freon refrigerant with a GWP (Global Warming Potential) of 1 is used as the refrigerant, thereby reducing the environmental impact. The refrigerant can be selected according to the controlled temperature range of the thermostatic bath. The refrigerant may be water, or a refrigerant with a lower boiling point than water, such as alcohol, may be used. When a refrigerant with a lower boiling point than water is used, it is more likely to evaporate even when the temperature is below the ambient temperature than water. This improves the efficiency of lowering the temperature to below the ambient temperature, and also makes it possible to expand the controlled temperature range of the thermostatic bath.

In the heat exchange section 40 in FIG. 1, heat from the thermostatic chamber is transferred to the refrigerant in the heat pipes 11 and 12. The refrigerant that has received the heat becomes gaseous and moves through the heat pipes 11 and 12 to the heat dissipation section 20 outside the thermostatic chamber.

In FIG. 2, the direction of movement of the refrigerant in the heat dissipation section 20 is indicated by an arrow. The refrigerant that receives heat in the heat exchange section 40 becomes gaseous and moves through the heat pipes 11 and 12 in the negative direction of the z axis (the direction of the arrow). At this time, the refrigerant is cooled by the ambient temperature in the heat dissipation section 20.

The refrigerant then moves to the heat absorption section 30 on the negative side of the z-axis, where heat is absorbed by the heat absorption surfaces 51, 52 of the Peltier element 50. This allows the refrigerant to be cooled to a temperature lower than that already reached by the heat dissipation section 20. The refrigerant that has absorbed heat becomes liquid and returns (circulates) from outside the thermostatic chamber back into the thermostatic chamber. Although not shown, in order to cool the Peltier element 50, an appropriate current is applied to the Peltier element 50 depending on the desired cooling temperature. The point at which the refrigerant becomes liquid can be either in the heat dissipation section 20 or the heat absorption section 30, depending on the type of refrigerant and the ambient temperature.

Meanwhile, the heat absorbed by the heat absorption section 30 is transferred to the refrigerant in the heat pipe 13 through the heat dissipation surfaces 53, 54 of the Peltier element 50. The refrigerant in the heated heat pipe 13 becomes gaseous, moves to the heat dissipation section 20 on the positive side of the z-axis, and is cooled by the ambient temperature. The cooled refrigerant changes state to liquid and flows back again to the negative side of the z-axis (up and down arrows in the heat pipe 13 in Figure 2).

The mechanism of constant temperature control of the heat pipe constant temperature bath 1 will be explained. First, the constant temperature bath is cooled as much as possible by the heat pipes 11 and 12 according to the ambient temperature. When controlling the temperature range below the cooled temperature, the Peltier element 50 is controlled and cooling is performed by the heat absorption section 30. By performing this two-stage control, the temperature of the constant temperature bath can be controlled below the ambient temperature, and constant temperature performance below the ambient temperature can be achieved. This configuration allows for efficient temperature control. Note that the Peltier element 50 reverses the heat absorption and radiation surfaces when a reverse current is applied, so temperature control such as heating by the heat absorption section 30 is possible in addition to cooling.

As described above, by cooling the Peltier element 50 with the heat pipe 13, the cooling efficiency of the Peltier element 50 can be improved. In other words, it is possible to provide a heat pipe thermostatic bath with excellent cooling efficiency for the Peltier element 50.

If the cooling efficiency of the Peltier element 50 can be increased, there is no need to use a separate cooling device to cool the Peltier element 50, and the power consumption required to use that cooling device can be reduced. Furthermore, if the cooling efficiency of the Peltier element 50 can be increased, the amount of Peltier element 50 used for a specified temperature control can be reduced, and the power consumption required to use the Peltier element 50 can be reduced. From the above, the use of the heat pipe thermostatic bath 1 according to the present invention can reduce power consumption. Reducing power consumption can contribute to reducing CO2 emissions.

The present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit and scope of the invention.

REFERENCE SIGNS LIST 1 heat pipe thermostatic chamber 11, 12, 13 heat pipe 20 heat dissipation section 30 heat absorption section 40 heat exchange section 50 Peltier element 51, 52 heat absorption surface 53, 54 heat dissipation surface

Claims (1)

a first heat pipe and a second heat pipe provided between the inside and the outside of the thermostatic chamber, through which a refrigerant circulates;
a heat dissipation unit that dissipates heat from the first and second heat pipes outside the thermostatic chamber;
a heat exchanger provided in the thermostatic chamber and configured to transfer heat from within the thermostatic chamber to the first and second heat pipes;
a heat absorbing unit that is provided outside the thermostatic chamber between the heat exchange unit and the heat dissipation unit and absorbs heat from the first and second heat pipes using a Peltier element;
a third heat pipe provided across the heat dissipation portion and the heat absorption portion and configured to transfer heat dissipated from the Peltier element to the heat dissipation portion;
the third heat pipe is disposed between the first and second heat pipes;
the Peltier element is a pair of Peltier elements provided between the third heat pipe and the first and second heat pipes in the heat absorption portion,
the heat absorbing surfaces of the pair of Peltier elements are provided so as to be in contact with the first and second heat pipes,
each of the heat dissipation surfaces of the pair of Peltier elements is provided so as to be in contact with the third heat pipe;
The heat radiated from the heat radiating surfaces of the pair of Peltier elements is transferred to the heat radiating portion via the third heat pipe.
Heat pipe thermostatic chamber.

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