JP4254448B2 - Thermal storage unit setting method for constant temperature control unit - Google Patents

Description

The present invention relates to a heat storage body setting method for a constant temperature control unit, and more particularly, to a heat storage body setting method for a constant temperature control unit suitable for reducing temperature fluctuation of a fluid supplied to a constant temperature chamber.

  When performing highly accurate laser measurement or laser processing, the optical path of the laser beam may change due to changes in the temperature, humidity, and pressure of the air in the constant temperature chamber in which measurement or processing is performed. In order to prevent this change in the optical path, it is necessary to keep the temperature, humidity and pressure of the air in the constant temperature chamber constant. In order to keep the temperature of the air constant, the constant temperature chamber is provided with a constant temperature control unit that circulates the air in the constant temperature chamber and keeps the temperature of the air constant. This constant temperature control unit has a configuration in which a cooling coil, a fan, and a heater are connected in order from the exhaust side of the constant temperature chamber via a duct, and the latter stage of the heater is connected to the supply side of the constant temperature chamber. The air exhausted from the chamber is cooled by a cooling coil and then supplied by a fan. The supplied air is heated to a set temperature by a heater and supplied to a constant temperature chamber. In this configuration, when the air is heated by the heater, the temperature fluctuates. However, if the heater is controlled with high accuracy, the temperature fluctuation can be reduced to about ± 0.01 ° C.

  In addition, a number of small passages are bundled in front of the supply port through which air is supplied into the constant temperature chamber, and at least a part of the small passages are inclined so that the positions of the air intake port and the outlet are displaced from each other. There is an invention in which a laminated airflow mixing means and a fine mixing means in which a filling material having a large space ratio is packed inside a frame frame sized to block the passage cross section are available. This configuration has the effect of mixing the airflows at distant positions in the passage with each other and eliminating the temperature distribution of the airflow in the narrow cross section, achieving a temperature distribution of ± 0.01 ° C in space and time (Patent Document 1).

  Further, there is an invention in which a bent pipe is laminated in a bent duct along the flow direction of air flowing in the duct. This structure has the effect of increasing the rigidity of the bent duct and preventing a large secondary flow of air flowing in the bent duct, but it is intended to reduce the temperature fluctuation of the air flowing in the duct. Not (Patent Document 2).

JP-A-6-66434 Japanese Patent Laid-Open No. 11-157445

  When controlling the heater of the constant temperature control unit, the temperature of the air is measured by a temperature sensor provided at the subsequent stage of the heater, and the control device controls the heater based on the measured temperature. However, since the temperature of the air output from the heater fluctuates with time, the heater is controlled after the temperature is measured, and the air is warmed. However, there was a problem that proper temperature control could not be performed on the air. In addition, since the temperature of the air output from the heater fluctuates at various frequencies, there is a problem that the control device cannot cope with all the frequencies where the temperature fluctuates. For this reason, in the constant temperature control unit using a control apparatus, there existed a problem that the highly accurate temperature control which makes the temperature fluctuation of air below ± 0.001 degreeC cannot be performed.

  Moreover, since the invention described in Patent Document 1 only mixes the air flowing in the duct by the airflow mixing means and the fine mixing means, the temperature fluctuation cannot be reduced to ± 0.001 ° C. or less.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a heat storage body setting method for a constant temperature control unit that extremely reduces the temperature fluctuation of the fluid supplied to the constant temperature chamber.

In order to achieve the above object, a method for setting a heat storage body of a constant temperature control unit according to the present invention is a method for setting a constant temperature control unit having a heat storage body arranged in a fluid passage for supplying a temperature-controlled fluid to a constant temperature chamber. Therefore, when changing the heat transfer area and heat capacity of the heat storage body, check the frequency range where the temperature fluctuation is small in advance and make it correspond to the high frequency area of the temperature control fluid of the temperature control fluid you want to reduce the temperature fluctuation. with selecting the regenerator at the value of the heat capacity Te, it is characterized in that by selecting a thermal storage medium disposed in said fluid passage so as to correspond to a lower frequency region in the value of heat transfer area.

  Even temperature-controlled fluid has slight temperature fluctuations and fluctuates at various frequencies. When the fluid passes through the porous passage member, heat exchange is performed between the fluid and the heat storage body. This heat exchange releases heat to the heat storage body when the temperature of the fluid is high, and absorbs heat from the heat storage body when the temperature of the fluid is low. By this heat exchange, the temperature of the fluid becomes more constant, and the temperature fluctuation of the fluid can be reduced. If the heat capacity of the heat storage body is increased, the temperature fluctuation on the low frequency side can be reduced, and if the surface area of the heat storage body is increased, the temperature fluctuation on the high frequency side tends to be reduced. For this reason, if the heat capacity and surface area of the heat storage body are selected corresponding to the temperature fluctuation frequency of the temperature control fluid, the temperature fluctuation of the temperature control fluid can be reduced.

The heat storage body is formed of a plurality of materials having different heat capacities and surface areas, and is arranged in series in the fluid passage. A fluid that fluctuates at a low frequency is more susceptible to the heat capacity than the surface area of the heat storage body. Moreover, the fluid which fluctuates at a high frequency is more easily affected by the size of the surface area than the size of the heat capacity of the heat storage body. That is, if a heat storage body having a larger heat capacity is used, temperature fluctuation on the low frequency side can be reduced, and if a heat storage body having a larger surface area is used, temperature fluctuation on the high frequency side can be reduced. For this reason, if a heat storage body with a large heat capacity and a heat storage body with a large surface area are arranged in series, temperature fluctuations can be reduced over a wide frequency range.

The heat storage body is formed of a plurality of materials having different heat capacities, and is compositely arranged in the same cross section of the fluid passage. The fluid flowing in the fluid passage may have different temperature fluctuations or temperature fluctuation frequencies along the cross-sectional direction of the fluid passage. At this time, if materials having different heat capacities in the same cross section are arranged on the heat storage body in accordance with the temperature fluctuation and the temperature fluctuation frequency, the distribution of the temperature fluctuation and the temperature fluctuation frequency in the same cross section is eliminated. As a result, the fluid becomes uniform in the same cross section, and the temperature variation of the fluid can be reduced.

According to the present invention described above, there is provided a constant temperature control unit having a heat storage body disposed in a fluid passage for supplying a temperature-controlled fluid to a constant temperature chamber, wherein the heat storage body is formed by a porous passage member and temperature control is performed. Since the heat capacity value of the heat storage body and the shape of the porous passage member are selected corresponding to the temperature fluctuation frequency of the fluid, the temperature fluctuation of the fluid passing through the heat storage body can be extremely reduced. .

Below, the thermal storage body setting method of the constant temperature control unit which concerns on this invention is demonstrated. In addition, although embodiment described below demonstrates as a structure using air as a fluid, this is only one Embodiment of this invention, and this invention is not limited to this.

  First, the first embodiment will be described. FIG. 1 is an explanatory diagram of a constant temperature control unit according to the first embodiment. The constant temperature control unit 20 is configured such that a constant temperature chamber 22, a cooling coil 24, a fan 26 and a heater 28 are connected by a fluid passage 30 (duct 30), and air is circulated through them. That is, a cooling coil 24 for cooling the discharged air is provided on the output side where the air is discharged from the constant temperature chamber 22. The cooling coil 24 is connected to the chiller 32 by a pipe 34, and the refrigerant circulates inside these. A fan 26 is provided at the subsequent stage of the cooling coil 24, and the air passing through the cooling coil 24 is sent to the subsequent stage side by the fan 26. A heater 28 is provided at the subsequent stage of the fan 26, and the air is heated to a preset temperature by the heater 28 to adjust the temperature. In this embodiment, the heater 28 is provided in two stages. However, depending on the design of the constant temperature control unit 20, the heater may be provided in one stage, or three or more stages may be provided. The temperature of the air that has passed through the heater is adjusted, but has a slight temperature fluctuation. This air is combined with air having various speeds of temperature fluctuation, such as when the temperature fluctuates quickly or fluctuates slowly. The speed of temperature fluctuation can be expressed as a temperature fluctuation frequency.

  And in the duct 30 of the back | latter stage of the heater 28, the thermal storage body 10 for making temperature fluctuation of air small is provided. FIG. 2 is an explanatory diagram of the heat storage body according to the first embodiment. The heat storage body 10 is composed of a plurality of porous passage members 12, and air passes through holes provided in the porous passage member 12, so that the air and the heat storage body 10 exchange heat. For this reason, it is preferable that the heat storage body 10 has a large surface area (heat transfer area) in order to facilitate heat exchange with air. That is, the porous passage member 12 having a plurality of small holes is preferable. In this porous passage member 12, for example, the side surfaces of a plurality of pipe members are formed in close contact (see FIG. 2 (a)), a honeycomb structure member (see FIG. 2 (b)), and a flat plate member in a lattice shape. A formed member (see FIG. 2C), a porous member having a large number of holes and a low density is used.

  Moreover, since the heat storage body 10 absorbs heat when the temperature of air is high and releases heat when the temperature of air is low, it is preferable that the temperature of the heat storage body 10 itself hardly changes. Therefore, a material having a large heat capacity, such as a metal such as aluminum or copper, is used for the heat storage body 10. By the way, the heat storage body 10 cannot reduce temperature fluctuation over a wide frequency range in which temperature fluctuation occurs. That is, the heat transfer area and the heat capacity are different depending on the shape and material of the heat storage body 10, and the frequency range in which the temperature fluctuation can be reduced is different depending on the heat transfer area and the heat capacity. For this reason, you have to select the thermal storage body 10 according to the frequency which wants to make temperature fluctuation of air small. This is because the frequency range in which the temperature fluctuation is reduced when the heat storage area 10 or the heat capacity of the heat storage body 10 is changed is examined in advance, and the frequency at which the temperature fluctuation is desired to be reduced using this result. The size of the heat transfer area of the heat storage body 10 and the value of the heat capacity of the heat storage body 10 may be selected. Note that air that fluctuates at a low frequency is more susceptible to the heat capacity than the heat transfer area of the heat storage body 10, and air that fluctuates at a high frequency has a heat transfer area larger than the heat capacity of the heat storage body. There is a tendency to be easily affected by size. For this reason, when it is desired to reduce the temperature fluctuation on the low frequency side, the heat storage body 10 having a larger heat capacity is selected. When it is desired to reduce the temperature fluctuation on the high frequency side, the heat storage body having a large heat transfer area is selected. 10 will be selected.

  The heat storage body 10 is provided on the entire surface of the duct 30 in the cross-sectional direction. That is, all the air passing through the duct 30 passes through the heat storage body 10. The heat accumulator 10 may be disposed directly on the duct 30, or a frame shape in which a frame portion corresponding to the size of the outer periphery of the cross section of the duct 30 is formed and the heat accumulator is disposed in the frame portion. It is good also as a heat storage body. When the frame-type heat storage body is formed, the frame-type heat storage body can be easily attached to and detached from the duct 30, and the heat storage body can be easily replaced.

  Further, the inventor has repeatedly studied in order to reduce the temperature fluctuation of the air, and has found that if the length of the heat storage body 10 is increased, the temperature fluctuation can be further reduced. It has also been found that the greater the heat capacity of the heat storage body 10, the smaller the low frequency temperature fluctuation. Further, the larger the heat transfer area of the heat storage body 10, that is, the longer the heat storage body 10 is, or the more closely the porous passage member 12 is arranged densely, the more the air per unit time and the heat of the heat storage body 10 are. It has been found that the exchange rate is increased and the high-frequency temperature fluctuation can be reduced.

  Next, the operation of the constant temperature control unit 20 will be described. The air discharged from the output side of the constant temperature chamber 22 is heat-exchanged with the solvent by the cooling coil 24 and cooled to a constant temperature. The cooled air is sent to the heater 28 by the fan 26. The heater 28 warms the air to a set temperature and adjusts the temperature before outputting. At this time, the air output from the heater 28 is output with a minute temperature fluctuation and has various temperature fluctuation frequencies. FIG. 3 shows the relationship between temperature fluctuation and time. The graph shown at the top of FIG. 3 shows the temperature variation of the air immediately after passing through the heater 28. From this figure, it can be seen that the temperature variation of the air output from the heater 28 is not constant over time and has various amplitudes. FIG. 4 shows the relationship between the frequency of the temperature fluctuation immediately after the air passes through the heater and the frequency. FIG. 4 shows the magnitude of the temperature fluctuation at each frequency, and it can be seen that the air immediately after passing through the heater 28 has a large temperature fluctuation intensity in a wide range of frequencies.

  The air output from the heater 28 passes through the holes of the porous passage member 12 constituting the heat storage body 10. At this time, when the temperature of the air is high, heat is released to the heat storage body 10, and when the temperature of the air is low, the heat is absorbed from the heat storage body 10. This heat exchange reduces the temperature fluctuation of the air. In FIG. 3, the second graph from the top shows the relationship between the temperature variation of the air passing through the heat storage body having a large heat capacity and the time. The graph in the third row shows the relationship between the temperature variation of the air passing through the heat storage body having a large heat transfer area and time. From these graphs, it can be seen that the air passing through the heat accumulator 10 has a smaller temperature fluctuation than the air immediately after passing through the heater.

  FIG. 5 shows the relationship between the intensity of the temperature fluctuation of the air passing through the heat storage body having a large heat capacity and the frequency. FIG. 6 shows the relationship between the frequency of the temperature fluctuation of the air passing through the heat storage body having a large heat transfer area and the frequency. From these figures, the intensity of the temperature fluctuation of the air that has passed through the heat accumulator having a large heat capacity or the heat accumulating area having a large heat transfer area is greater than the temperature fluctuation of the air immediately after passing through the heater 28 at all frequencies. It can be seen that the temperature fluctuation is small. In particular, it can be seen that the intensity of the temperature fluctuation of the air on the low frequency side is smaller in the case of using the heat storage body having a large heat capacity than in the case of using the heat storage body having a large heat transfer area. Moreover, it turns out that the intensity | strength of the temperature fluctuation of the air in the high frequency side is smaller at the time of using the thermal storage body with a large heat-transfer area compared with the case where the thermal storage body with a large heat capacity is used.

FIG. 7 shows the relationship between the temperature variation ratio and the frequency at the inlet and outlet of the heat storage body 10. Also from FIG. 7, it is more effective to reduce the temperature fluctuation by using a heat storage body having a large heat capacity on the low frequency side, and using the heat storage body having a large heat transfer area on the high frequency side. It turns out that it is effective to make small.
Then, the air that has passed through the heat storage body 10 and has a small temperature fluctuation is supplied to the constant temperature chamber 22.

  According to such a configuration, the heat storage body 10 is provided in the front stage of the supply port through which air is supplied to the constant temperature chamber 22, and heat exchange is performed through the air output from the heater 28 to the heat storage body 10, thereby Variation can be reduced. Thereby, air with a small temperature fluctuation can be supplied to the constant temperature chamber 22. Further, if the length of the heat storage body 10 is increased, the temperature fluctuation can be further reduced.

  Further, since the temperature fluctuation of the air can be reduced by the heat exchange between the air and the heat storage body 10, it is possible to cope with the temperature fluctuation of a wide range of frequencies. If a heat storage body made of a material having a larger heat capacity is used, low-frequency temperature fluctuations can be reduced, and if a heat storage body made of a material having a larger heat transfer area is used, high-frequency temperature fluctuations can be reduced.

  Moreover, since the heat storage body 10 is provided on the entire cross section of the duct 30, the temperature of the air passing through the heat storage body 10 does not have a different temperature distribution in the cross section direction of the duct 30. Therefore, air having a uniform temperature in the cross-sectional direction of the duct 30 can be supplied to the constant temperature chamber 22.

  In addition, in this embodiment, although the heat storage body 10 is formed as the same material, cross-sectional shape, and a dimension, the heat storage body 10 is formed from several materials from which heat capacity differs, or the heat transfer area is changed, and the same cross section of the duct 30 It can also be arranged in a composite manner. This is used when the air output from the heater 28 has a different temperature fluctuation distribution with respect to the cross-sectional direction of the duct 30, or when the air fluctuation frequency has a different distribution with respect to the cross-sectional direction of the duct 30. Thereby, while the temperature fluctuation of the air output from a thermal storage body can be made small, distribution with respect to the cross-sectional direction of the duct 30 can be made constant.

  Next, a second embodiment will be described. The inventor has repeatedly studied to further reduce the temperature fluctuation of the air supplied to the constant temperature chamber 22, and further increases the temperature from the value of the temperature fluctuation obtained when the temperature fluctuation is reduced using one heat storage body 10. It has been found that the length of the heat storage element 10 must be increased by three times or more in order to reduce the fluctuation, that is, to make the temperature fluctuation ± 0.001 ° C. or less. However, it is impossible to make the length of the heat storage body 10 longer than that in the configuration of the constant temperature control unit 20. That is, it is difficult to increase the heat capacity and heat transfer area of the heat storage body 10 at the same time. For this reason, a heat storage body with a large heat capacity that reduces temperature fluctuations on the low frequency side and a heat storage body with a large heat transfer area that reduces temperature fluctuations on the high frequency side are arranged in series so that temperature fluctuations can be achieved over a wide frequency range. While reducing the size, the heat storage body was reduced in size.

  In the constant temperature control unit 20 according to the second embodiment, a heat storage body having a large heat capacity and a heat storage body having a large heat transfer area are arranged in series in the duct 30 at the rear stage of the heater 28, and each of the heat storage bodies 10a at the front stage. One of the rear heat storage elements 10b is configured. The heat accumulators 10a and 10b are arranged in the duct 30 with the same configuration as in the first embodiment. In these heat storage bodies 10a and 10b, the temperature fluctuations corresponding to the frequency are attenuated depending on the heat capacity and the heat transfer area. Therefore, an appropriate heat storage body is selected according to the frequency at which the temperature fluctuations are desired to be reduced. This selection is performed by examining in advance the relationship between the heat storage body to be used and the frequency band in which the temperature fluctuation is reduced by using this heat storage body. In addition, whichever may be arrange | positioned first in the order which arrange | positions the thermal storage body with a large heat capacity, and the thermal storage body with a large heat-transfer area. Moreover, it is good also as a structure which arrange | positions 3 or more types of thermal storage bodies in series depending on the kind of thermal storage body.

In such a constant temperature control unit 20, the air output from the heater 28 passes through the hole of the heat storage body 10a in the previous stage. At this time, when the temperature of the air is high, heat is released to the heat storage body 10a, and when the temperature of the air is low, the heat is absorbed from the heat storage body 10a. Furthermore, the air whose temperature fluctuation has been reduced by passing through the front heat storage body 10a passes through the holes of the rear heat storage body 10b. At this time, the same action as when passing through the preceding heat storage element 10a is performed, and the temperature variation of the air is further reduced. The graph shown at the bottom of FIG. 3 shows the relationship between the temperature fluctuation of the air that has passed through the front heat storage body 10a and the rear stage 10b and time. From FIG. 3, it can be seen that the temperature fluctuation becomes extremely small when the air passes through the front heat storage body 10 a and the rear heat storage body 10 b. The spectrum shown at the bottom of FIG. 7 shows the ratio of temperature fluctuations at the inlet of the heat storage body 10a at the front stage and the outlet of the heat storage body 10b at the rear stage. Further, FIG. 8 shows the relationship between the frequency and the frequency of the temperature fluctuation of the air passing through the heat storage body having a large heat capacity and the heat storage body having a large heat transfer area. From FIG. 7 and FIG. 8, the intensity of the temperature fluctuation over a wide range of frequencies is smaller in the air that has passed through the first heat storage body 10 a and the second heat storage body 10 b than in the air that has passed only one stage through the heat storage body. I understand that.
The air that has passed through the heat accumulators 10 a and 10 b and has a very small temperature fluctuation is supplied to the constant temperature chamber 22.

  According to such a configuration, the heat storage bodies having different characteristics are arranged in series in the duct 30, the temperature fluctuation on the low frequency side is reduced in one heat storage body, and the temperature on the high frequency side is reduced in the other heat storage body. The fluctuation is reduced. Therefore, by combining the heat accumulators, temperature fluctuations in a wide range of frequencies can be made extremely small, and highly accurate temperature control can be realized. And the temperature in the constant temperature chamber 22 can be made constant. Moreover, it can respond to various temperature fluctuation frequencies by changing the combination of heat storage bodies. When the heat storage body having a large heat capacity and the heat storage body having a large heat transfer area are combined and disposed in the constant temperature control unit 20, the temperature fluctuation of the air supplied to the constant temperature chamber 22 can be reduced to ± 0.001 ° C. or less. It was.

  Further, as described above, the heat storage body having a large heat capacity for reducing temperature fluctuation on the low frequency side and the heat storage body having a large heat transfer area for reducing temperature fluctuation on the high frequency side are arranged in series. This provides the same effect as providing only one stage of the heat storage body to increase both the heat capacity and the heat transfer area, that is, using a heat storage body having a large heat capacity, and increasing the length of the heat storage body three times or more. For this reason, the length of the whole heat storage body is shortened by combining the heat storage bodies having different characteristics, compared with the case where only one stage of the heat storage body is provided and the temperature fluctuation of the air is reduced to ± 0.001 ° C. or less. be able to. That is, the heat storage body can be reduced in size.

FIG. 2 is an explanatory diagram of a constant temperature control unit according to the first embodiment. It is explanatory drawing of the thermal storage body which concerns on 1st Embodiment. It is a figure which shows the relationship between temperature fluctuation and time. It is a figure which shows the relationship between the intensity | strength of the temperature fluctuation in the air immediately after a heater passage, and a frequency. It is a figure which shows the relationship between the intensity | strength of the temperature fluctuation of the air which passed the thermal storage body with large heat capacity, and a frequency. It is a figure which shows the relationship between the intensity | strength of the temperature fluctuation of the air which passed the thermal storage body with a large heat-transfer area, and a frequency. It is a figure which shows the relationship between the temperature variation ratio in the inlet_port | entrance and exit of a thermal storage body, and a frequency. It is a figure which shows the relationship between the intensity | strength of the temperature fluctuation of the air which passed the thermal storage body with a large heat capacity, and the thermal storage body with a large heat-transfer area, and a frequency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ......... Storage body, 20 ......... Constant temperature control unit, 22 ......... Constant temperature chamber, 24 ......... Cooling coil, 26 ......... Fan, 28 ......... Heater.

Claims (2)

A method for setting a constant temperature control unit having a heat storage body arranged in a fluid passage for supplying a temperature-controlled fluid to a constant temperature chamber, wherein the temperature fluctuation is small when the heat transfer area or heat capacity of the heat storage body is changed. The heat storage is selected according to the heat capacity value corresponding to the high frequency region of the temperature control fluid whose temperature fluctuation is desired to be reduced, and the heat transfer corresponding to the low frequency region. A heat storage body setting method for a constant temperature control unit, wherein a heat storage body is selected based on an area value and disposed in the fluid passage. 2. The method of setting a heat storage body of a constant temperature control unit according to claim 1, wherein the setting of the constant temperature control unit is applied to high-accuracy temperature control that makes temperature fluctuation of the temperature control fluid ± 0.001 ° C. or less.

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