ISOTHERMAL HEATING APPARATUS

Abstract

An isothermal heating apparatus includes a plate including formed therein a heat pipe circuit in which working fluid is charged, and a heating mechanism heating the working fluid. The heat pipe circuit includes a header portion at which the working fluid is heated and evaporated and a plurality of branch portions in which vapor produced by vaporization of the working fluid exchanges heat with the plate and condensates, the branch portions branching off from the header portion. The heating mechanism is provided on an evaporating surface side of the header portion with which the working fluid is in contact when the heating mechanism heats the working fluid. The isothermal heating apparatus can achieve isothermal heating of a heat-treatment subject and size reduction of the apparatus.

Description

TECHNICAL FIELD

The present invention relates to an isothermal heating apparatus that heats a heat-treatment subject into an isothermally heated state.

BACKGROUND ART

A conventional technique regarding an isothermal heating plate that heat-treats a heat-treatment subject into an isothermally heated state is disclosed in, for example, Japanese Laid-Open Patent Publication No. 9-314561 (PTL 1) or Japanese Laid-Open Patent Publication No. 2007-294688 (PTL 2).

FIG. 20 is a perspective view showing a structure of an example of a conventional isothermal heating plate. An isothermal heating plate shown in FIG. 20 has a structure in which the both ends of each of a plurality of through holes 102a formed in a plate 101 are closed with lids 107a and 107b to form a sealed container 107, the inside of this sealed container 107 is evacuated and then a predetermined amount of working fluid is charged, and a heater 106 is brought into thermal contact with the bottom of plate 101 with a heat transfer block 104 interposed therebetween.

FIG. 21 is a plan view showing a structure of another example of a conventional isothermal heating plate. FIG. 22 is a side view showing the structure of the other example of the conventional isothermal heating plate. The isothermal heating plate shown in FIGS. 21 and 22 has a pipe 123 arranged in a plurality of holes formed in a plate 121 to form a meandering circuit of a pipe container, and has an evaporator 143 with an entrance 141 serving as one end of the meandering circuit being connected to the upper part and an exit 142 serving as the other end of the circuit being connected to the lower part to form a single communication circuit with the meandering circuit. The inside of this single communication circuit is evacuated and then a predetermined amount of working fluid 131 is charged, and working fluid 131 is heated by a heater 126 fitted in evaporator 143.

CITATION LIST

Patent Literature

• PTL 1: Japanese Laid-Open Patent Publication No. 9-314561
• PTL 2: Japanese Laid-Open Patent Publication No. 2007-294688

SUMMARY OF INVENTION

Technical Problem

As described above, various techniques for the isothermal heating apparatus that isothermally heats a heat-treatment subject have been proposed so far. However, the isothermal heating apparatus is requested to have the capability of heating a subject much more isothermally, and in addition, size reduction of the apparatus is also required. The conventional apparatus disclosed in each piece of literature mentioned above do not necessarily satisfy these points, but there is still room for improvement.

The present invention was made in view of the above-described problems, and has a main object to provide an isothermal heating apparatus capable of isothermally heating a heat-treatment subject and achieving size reduction of the apparatus.

Solution to Problem

An isothermal heating apparatus according to the present invention includes a plate having formed therein a heat pipe circuit in which a working fluid is charged, and heating means heating the working fluid. The heat pipe circuit includes a header portion at which the working fluid is heated and evaporated and a plurality of branch portions in which vapor produced by vaporization of the working fluid exchanges heat with the plate and condensates, the branch portions branching off from the header portion. The heating means is provided on a wall surface side of the header portion with which the working fluid is in contact when the heating means heats the working fluid.

In the above-described isothermal heating apparatus, preferably, the plate is formed to have a rectangular shape in plan view, the header portion extends along one side surface of the plate, and the branch portions are provided to extend toward an other side surface of the plate opposed to the one side surface.

In the above-described isothermal heating apparatus, preferably, the plurality of branch portions are arranged in parallel to one another. Still preferably, the heat pipe circuit further includes a coupling portion coupling the branch portions. The coupling portion may couple tips of the branch portions extending from the header portion. A plurality of the coupling portions may be provided and may be arranged in parallel to one another.

In the above-described isothermal heating apparatus, preferably, the heating means includes a heater, a heat transfer block formed with a recess and storing the heater in the recess, and a heater holding plate holding the heater in the recess.

In the above-described isothermal heating apparatus, preferably, the heating means includes a fixing member fixing the heater holding plate and the heat transfer block integrally to the plate.

The above-described isothermal heating apparatus may include a thermally conductive interposed member interposed between the plate and the heat transfer block. The heating means may include a thermally conductive interposed member interposed between the heat transfer block and the heater holding plate. The heating means may include a thermally insulative interposed member interposed between the heat transfer block and the heater holding plate.

In the above-described isothermal heating apparatus, preferably, a hollowed portion storing the heater is formed in the heater holding plate at a position opposed to the recess.

In the above-described isothermal heating apparatus, preferably, a high performance boiling surface promoting boiling of the working fluid is formed in the wall surface with which the working fluid is in contact where the working fluid is heated.

In the above-described isothermal heating apparatus, preferably, a width by which the heating means is in thermal contact with the plate is less than or equal to a width of the wall surface with which the working fluid is in contact where the working fluid is heated.

Advantageous Effects of Invention

According to the isothermal heating apparatus of the present invention, a heat-treatment subject can be heated isothermally, and size reduction of the apparatus can be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view of an isothermal heating apparatus of a first embodiment of the present invention.

FIG. 2 is a sectional view of the isothermal heating apparatus taken along the line II-II shown in FIG. 1.

FIG. 3 is a sectional view of the isothermal heating apparatus taken along the line shown in FIG. 1.

FIG. 4 is a sectional view showing details of the structure of heating means.

FIG. 5 is a sectional view showing a first variation of the isothermal heating apparatus of the first embodiment.

FIG. 6 is a sectional view showing a second variation of the isothermal heating apparatus of the first embodiment.

FIG. 7 is a sectional view showing a third variation of the isothermal heating apparatus of the first embodiment.

FIG. 8 is a sectional view of an isothermal heating apparatus of a second embodiment.

FIG. 9 is a sectional view of an isothermal heating apparatus of a third embodiment.

FIG. 10 is a sectional view of a variation of the isothermal heating apparatus of the third embodiment.

FIG. 11 is a sectional view of an isothermal heating apparatus of a fourth embodiment.

FIG. 12 is a sectional view of an isothermal heating apparatus of a fifth embodiment.

FIG. 13 is a sectional view of an isothermal heating apparatus of a sixth embodiment.

FIG. 14 is a sectional view showing another example of arrangement of a plate.

FIG. 15 is a sectional view showing another example of arrangement of a plate.

FIG. 16 is a plan view of an isothermal heating apparatus of a seventh embodiment.

FIG. 17 is a plan view of another example of the isothermal heating apparatus of the seventh embodiment.

FIG. 18 is a plan view of another example of the isothermal heating apparatus of the seventh embodiment.

FIG. 19 is a plan view of another example of the isothermal heating apparatus of the seventh embodiment.

FIG. 20 is a perspective view showing the structure of an example of a conventional isothermal heating plate.

FIG. 21 is a plan view showing the structure of another example of the conventional isothermal heating plate.

FIG. 22 is a side view showing the structure of the other example of the conventional isothermal heating plate.

DESCRIPTION OF EMBODIMENTS

Hereinbelow, embodiments of the present invention will be described based on the drawings. It is noted that, in the drawings, the same or corresponding portion has the same reference number allotted, and description thereof will not be repeated.

First Embodiment

FIG. 1 is a plan view of an isothermal heating apparatus of a first embodiment of the present invention. FIG. 2 is a sectional view of the isothermal heating apparatus taken along the line II-II shown in FIG. 1. As shown in FIGS. 1 and 2, the isothermal heating apparatus of the first embodiment includes a plate 1 having a rectangular plate shape. Plate 1 is made of a material having high thermal conductivity represented by, for example, copper, aluminum or the like. The material making up of plate 1 can be arbitrarily selected depending on isothermal property required of a heat-treatment subject.

Plate 1 is formed to have a rectangular shape in plan view. A front surface 1a which is one surface of plate 1 is formed flat such that a heat-treatment subject, such as an organic material for semiconductor manufacture, for example, can be mounted and heated thereon. Heating means 3 is attached to a rear surface 1b which is the other surface of plate 1.

As shown in FIG. 1, a heat pipe circuit 2 is formed in plate 1. Heat pipe circuit 2 includes a header portion 2b and a plurality of branch portions 2a branching off from header portion 2b. Header portion 2b is arranged to extend along a side surface 1c constituting one side surface of plate 1 when plate 1 formed to have a rectangular shape in plan view is planarly viewed. Branch portions 2a are provided to extend from header portion 2b toward a side surface 1d constituting the other side surface of plate 1 opposed to side surface 1c. Plurality of branch portions 2a are arranged in parallel to one another, as shown in FIG. 1. Each of plurality of branch portions 2a is coupled to header portion 2b on the side surface 1c side of plate 1. It is noted that the circuit in plate 1 is formed by joining a flat plate and a groove-processed plate, for example.

Heat pipe circuit 2 is formed by evacuating internal space 30 formed in plate 1, and then a predetermined amount of working fluid is charged in internal space 30. The working fluid is heated by heating means 3 as will be described later.

FIG. 3 is a sectional view of the isothermal heating apparatus taken along the line shown in FIG. 1. In FIG. 2, the sectional view of the isothermal heating apparatus in a cross section including the whole of header portion 2b and branch portions 2a of heat pipe circuit 2 from side surface 1c to side surface 1d of plate 1 is shown. In contrast, in FIG. 3, the sectional view of the isothermal heating apparatus in a cross section including only header portion 2b of heat pipe circuit 2 is shown. FIG. 3 illustrates the state where working fluid 31 is charged into header portion 2b of heat pipe circuit 2, and working fluid 31 is in contact with an evaporating surface 12 constituting the bottom of header portion 2b having a rectangular shape in cross section. In header portion 2b, working fluid 31 is in contact with evaporating surface 12 which is a wall surface of header portion 2b on the rear surface 1b side of plate 1.

Header portion 2b constituting a part of heat pipe circuit 2 and heating means 3 are arranged with plate 1 interposed therebetween. As shown in FIG. 3, header portion 2b of heat pipe circuit 2 has a width 1₁. The width by which heating means 3 is in thermal contact with plate 1 is a width 1₀. Width 1₀ by which heating means 3 is in thermal contact with plate 1 shall be less than or equal to width 1₁ of evaporating surface 12. By thus defining the dimensions of heat pipe circuit 2 and heating means 3, heat generated by heating means 3 is more easily transferred to working fluid 31 in header portion 2b.

If width 1₀ by which heating means 3 is in contact with plate 1 is larger than width 1₁ of evaporating surface 12 of header portion 2b, the amount of heat transferred by heat conduction from heating means 3 to front surface 1a through rear surface 1b of plate 1 may increase, causing the temperature to be nonuniform on the side surface 1c side and side surface 1d side, on front surface 1a of plate 1. By transferring heat generated by heating means 3 to working fluid 31 and isothermally heating the whole branch portions 2a by evaporation and condensation of working fluid 31 as will be described later, plate 1 can be heated as a whole more isothermally.

Width 1₀ by which heating means 3 is in contact with plate 1 may be made smaller than width 1₁ of evaporating surface 12 by about several millimeters, for example. The optimal dimensions vary depending on the material of plate 1, the wall thickness of plate 1 (after processing of heat pipe circuit 2), the thickness of plate 1 (i.e., the spacing between front surface 1a and rear surface 1b), the temperature area used, and the like.

FIG. 4 is a sectional view showing details of the structure of heating means 3, enlargedly showing side surface 1c and its surroundings in FIG. 2. As shown in FIG. 4, heating means 3 includes a heater 6, a heat transfer block 4, and a heater holding plate 10. Heat transfer block 4 is formed with a grooved recess 4a for fixing heater 6. Heater 6 as an example of heating member that supplies heat to working fluid 31 in heat pipe circuit 2 by generating heat is incorporated in recess 4a as a grooved portion formed in heat transfer block 4. Heat transfer block 4 has the function as a storing portion storing heater 6 in recess 4a. Heater 6 may be an electric heater, for example.

Heater 6 is fitted within recess 4a formed in heat transfer block 4, and the inside of recess 4a is filled with heater 6 and a heat transfer material 5. Heater 6 is held in recess 4a of heat transfer block 4 by heater holding plate 10. Heater holding plate 10 has the function as a holding member holding heater 6 in recess 4a.

Heat transfer block 4 is brought into close contact with and fixed to rear surface 1b immediately below header portion 2b in plate 1 with heater 6 sandwiched between heat transfer block 4 and heater holding plate 10 and with heater 6 and heater holding plate 10 crimped by a fixing bolt 9. Heating means 3 includes fixing bolt 9 as a fixing member fixing heater holding plate 10 and heat transfer block 4 integrally to plate 1.

Heat transfer block 4 is in thermal contact with a part of rear surface 1b which is one surface of plate 1, and the part of plate 1 is heated by heater 6 held in heat transfer block 4.

As to the operation of the isothermal heating apparatus having the above-described structure, the heat transport principle in the isothermal heating apparatus will be described with reference to FIGS. 2 and 4. In the heat transport principle diagrams of FIGS. 2 and 4, a heat flow 21 in the drawings indicates a heat flow from heating means 3 to plate 1. When heater 6 is turned on to generate heat, the heat is transferred to a contact surface 14 between plate 1 and heat transfer block 4 through heat transfer material 5 and heat transfer block 4. The heat is further transferred through the inside of plate 1 to evaporating surface 12 at the bottom of header portion 2b in plate 1. When the bottom of header portion 2b in plate 1 is heated by heat flow 21, the bottom of header portion 2b will be evaporating surface 12 where working fluid 31 evaporates.

On evaporating surface 12 in header portion 2b, working fluid 31 charged into the inside of plate 1 is heated. Since the inside of plate 1 is in a vacuum decompression state, working fluid 31, when heated, is vaporized promptly to produce a vapor bubble 32. Vapor bubble 32 moves up through working fluid 31 to become vapor 33 at the liquid surface of working fluid 31, and vapor 33 moves in heat pipe circuit 2 formed in plate 1 in the direction from the side surface 1c side to the side surface 1d side to branch off from header portion 2b, and flows into each of plurality of branch portions 2a.

Vapor 33 moves through internal space 30 formed in plate 1 to move to the front surface 1a side opposite to rear surface 1b to which heating means 3 is attached. Vapor 33 is condensed in each part in branch portions 2a of heat pipe circuit 2 while moving through internal space 30 from the side surface 1c side to the side surface 1d side, and discharges latent heat of condensation to the part of plate 1 that is in thermal contact with branch portions 2a. In this manner, vapor 33 is condensed by radiating heat to plate 1, and is transformed into a condensate fluid 34. Heat is transferred isothermally to plate 1 in the whole branch portions 2a while vapor 33 flows toward side surface 1d, and plate 1 absorbs heat from vapor 33, so that plate 1 is heated at an equal temperature.

Since the pressure of vapor 33 flowing through branch portions 2a is higher on the side surface 1c side of plate 1 and decreases toward the side surface 1d side, the water level of working fluid 31 in branch portions 2a is higher on the side surface 1d d side than on the side surface 1c side, as shown in FIG. 2. The level difference of water level causes working fluid 31 to flow back from the side surface 1d side to the side surface 1c side where working fluid 31 originally exists. In the isothermal heating apparatus of the present embodiment, the above-described heat transport from heater 6 to plate 1 is carried out repeatedly.

Header portion 2b functions as a heating portion where working fluid 31 is heated and evaporated. Branch portions 2a function as condensation portions where vapor 33 produced by evaporation of working fluid 31 exchanges heat with plate 1 and condenses. Header portion 2b has the function as a vapor distributing header that distributes vapor 33 produced in header portion 2b to plurality of branch portions 2a. Header portion 2b has the function as a liquid collection header where condensate fluid 34 produced by condensation of vapor 33 in plurality of branch portions 2a is collected. Each of plurality of branch portions 2a is, relative to header tubular header portion 2b, formed as a lateral branch tubular shape extending in the direction crossing (typically, orthogonal to) the direction in which header portion 2b extends.

According to the above-described isothermal heating apparatus, heating means 3 is provided on the evaporating surface 12 side which is the wall surface of header portion 2b with which working fluid 31 is in contact when heating means 3 heats working fluid 31 in the liquid state. Since evaporating surface 12 is positioned immediately above contact surface 14 where plate 1 and heat transfer block 4 are in contact, the amount of heat, of heat from heater 6, that is directly transferred to front surface 1a of plate 1 is small. Most of the heat from heater 6 is spent in heating working fluid 31 on evaporating surface 12. When heat pipe circuit 2 and heating means 3 have dimensions defined in FIG. 3, the amount of heat, of the heat generated by heater 6, that is transferred to working fluid 31 is much larger.

Therefore, working fluid 31 in plate 1 can be evaporated, while preventing the heat of heater 6 from being directly transferred to plate 1, and vapor 33 produced by evaporation of working fluid 31 can be diffused into every part in plate 1. Since working fluid 31 can be evaporated at header portion 2b in plate 1 to produce vapor 33 and vapor 33 can be condensed at branch portions 2a to heat plate 1, thermal uniformity of front surface 1a of plate 1 can be improved. Therefore, the heat-treatment subject mounted on front surface 1a of plate 1 can be heated isothermally.

In addition, in the above-described isothermal heating apparatus, plate 1 can be heated as a whole by one heating means 3, and a plurality of heaters as in the system shown in the conventional technique of FIG. 20 are not required. Therefore, the number of components can be reduced, and the manufacturing costs of the isothermal heating apparatus can thus be reduced. Moreover, since heat generated by heater 6 is promptly transferred to every part of plate 1 by the evaporation phenomenon of working fluid 31, the temperature rise of heater 6 can be suppressed and the amount of heat transferred to the surroundings can also be reduced. Thus, the required energy can be reduced, and the running costs of the isothermal heating apparatus can be reduced. In addition, since evaporating surface 12 is provided in plate 1, it is not necessary to provide an evaporator separately as in the conventional technique of FIGS. 21 and 22. Therefore, size reduction and further cost reduction of the isothermal heating apparatus can be achieved, and the heat capacity of plate 1 can be reduced, so that an isothermal heating apparatus having high thermal responsiveness can be obtained.

FIG. 5 is a sectional view showing a first variation of the isothermal heating apparatus of the first embodiment. The isothermal heating apparatus of the first variation shown in FIG. 5 differs from the structure shown in FIG. 4 in that a thermally conductive interposed member 7 interposed between plate 1 and heat transfer block 4 is provided. As shown in FIG. 5, when thermally conductive interposed member 7 is placed on contact surface 14 between rear surface 1b of plate 1 and heat transfer block 4, thermal contact resistance between rear surface 1b of plate 1 and heat transfer block 4 will be reduced.

Therefore, heat generated by heater 6 can be transferred to working fluid 31 through plate 1 more efficiently, so that thermal responsiveness of the isothermal heating apparatus is further improved. In addition, the amount of heat radiation radiated from the surfaces of heat transfer block 4 and heater holding plate 10 to the surroundings is reduced, so that an isothermal heating apparatus having higher thermal efficiency can be provided.

FIG. 6 is a sectional view showing a second variation of the isothermal heating apparatus of the first embodiment. The isothermal heating apparatus of the second variation shown in FIG. 6 differs from the structure shown in FIG. 5 in that heating means 3 includes a thermally conductive interposed member 8 interposed between heat transfer block 4 and heater holding plate 10. Heat generated by heater 6 is also transferred to heater holding plate 10 through heat transfer material 5. When interposing thermally conductive interposed member 8 between heat transfer block 4 and heater holding plate 10 as shown in FIG. 6, thermal resistance between heater holding plate 10 and heat transfer block 4 will be reduced, so that heat is more likely to be transferred from heater holding plate 10 to heat transfer block 4 as a heat flow 22 indicated by an arrow of broken line.

Therefore, the amount of heat lost by radiation to the surroundings, of heat transferred to heater holding plate 10, can be reduced and heat flow 22 from heater holding plate 10 to heat transfer block 4 can be increased, so that the heat generated by heater 6 can be transferred to heat transfer block 4 still more efficiently. As a result, since heat transferred from heat transfer block 4 to working fluid 31 through plate 1 to heat working fluid 31 increases, thermal responsiveness of the isothermal heating apparatus can further be improved.

FIG. 7 is a sectional view showing a third variation of the isothermal heating apparatus of the first embodiment. The isothermal heating apparatus of the third variation shown in FIG. 7 differs from the structure shown in FIG. 5 in that heating means 3 includes a thermally insulative interposed member 8a interposed between heat transfer block 4 and heater holding plate 10. FIG. 6 illustrates the example where thermally conductive interposed member 8 is interposed between heat transfer block 4 and heater holding plate 10. In contrast, the amount of heat flow flowing from heater 6 to heater holding plate 10 can be reduced by interposing thermally insulative interposed member 8a between heat transfer block 4 and heater holding plate 10 as shown in FIG. 7.

Therefore, the amount of heat radiated from heater holding plate 10 to the surroundings can be reduced, so that the heat generated by heater 6 can be transferred to heat transfer block 4 still more efficiently. As a result, since heat transferred from heat transfer block 4 to working fluid 31 through plate 1 to heat working fluid 31 increases, thermal responsiveness of the isothermal heating apparatus can further be improved. In this case, heater holding plate 10 may be made of a material having low thermal conductivity.

Second Embodiment

FIG. 8 is a sectional view of an isothermal heating apparatus of a second embodiment. The isothermal heating apparatus of the second embodiment differs from the first embodiment in that heating means 3 does not include heat transfer block 4.

That is, in heating means 3 of the second embodiment, heat transfer block 4 is not used, but a groove-like hollowed portion 10a for fixing heater 6 is formed in heater holding plate 10. Heater 6 is incorporated in hollowed portion 10a as a groove portion formed in heater holding plate 10. Heater 6 is stored in hollowed portion 10a formed in heater holding plate 10, and in its surroundings, heat transfer material 5 is arranged. The inside of hollowed portion 10a is filled with heater 6 and heat transfer material 5.

Heater holding plate 10 is fixed by fixing bolt 9 in direct close contact with rear surface 1b immediately below header portion 2b in plate 1. When heating means 3 is constructed in this manner, the number of components of the isothermal heating apparatus is reduced by not using heat transfer block 4, so that cost reduction of the isothermal heating apparatus can be achieved.

Third Embodiment

FIG. 9 is a sectional view of an isothermal heating apparatus of a third embodiment. The isothermal heating apparatus of the third embodiment differs from the first and second embodiments in that the location where heater 6 is fixed is changed. More specifically, the first embodiment presents a structure in which heat transfer block 4 and heater holding plate 10 included in heating means 3 are both fixed to plate 1 using fixing bolt 9, and heat transfer block 4 is removable from plate 1. In the second embodiment, heater 6 is incorporated in groove-like hollowed portion 10a for fixing heater 6 to heater holding plate 10. On the other hand, in the third embodiment, heat transfer block 4 and plate 1 are thermally integrated by a method such as brazing or welding.

In the first and second embodiments, the part fixing heater 6 (heat transfer block 4 in the first embodiment and heater holding plate 10 in the second embodiment) is a member different from plate 1, and thermal contact resistance occurs because contact surface 14 between the part fixing heater 6 and plate 1 is not in full close contact. Even when thermally conductive interposed member 7 is arranged between heat transfer block 4 and plate 1, it is difficult to fully eliminate thermal resistance between heat transfer block 4 and plate 1 though thermal contact resistance is reduced. In contrast, in the third embodiment, thermal resistance between heat transfer block 4 and rear surface 1b of plate 1 can be minimized by thermally integrating heat transfer block 4 and plate 1 as shown in FIG. 9.

Therefore, when heat generated by heater 6 and transferred to heat transfer block 4 is further transferred to the plate 1 side through contact surface 14 between heat transfer block 4 and plate 1, part of heat energy can be prevented from being lost. As a result, the amount of heat transferred from heat transfer block 4 to working fluid 31 through plate 1 to heat working fluid 31 increases, so that thermal responsiveness of the isothermal heating apparatus can further be improved.

FIG. 10 is a sectional view of a variation of the isothermal heating apparatus of the third embodiment. Comparing FIGS. 9 and 10, hollowed portion 10a storing heater 6 is formed at a position of heater holding plate 10 opposed to recess 4a in the variation shown in FIG. 10. Heater 6 is disposed in the inside of recess 4a formed in heat transfer block 4 and in the inside of hollowed portion 10a formed in heater holding plate 10. The inside of space formed by recess 4a and hollowed portion 10a is filled with heater 6 and heat transfer material 5.

The effect of the isothermal heating apparatus of the third embodiment described with reference to FIG. 9 that can reduce thermal resistance between heat transfer block 4 and rear surface 1b of plate 1 does not depend on the size of heat transfer block 4. That is, as shown in FIG. 10, a similar effect can also be obtained by reducing the size of heat transfer block 4 and increasing the size of heater holding plate 10. In addition, in the variation shown in FIG. 10, because heat transfer block 4 is reduced in size, plate 1 can be cut out and processed from a somewhat larger material integrally with heat transfer block 4. Therefore, the production time of the isothermal heating apparatus can be shortened, and the manufacturing costs can be reduced.

Fourth Embodiment

FIG. 11 is a sectional view of an isothermal heating apparatus of a fourth embodiment. The isothermal heating apparatus of the fourth embodiment has a structure in which heater holding plate 10 of heating means 3 of the third embodiment is metallically joined and integrated to heat transfer block 4.

If heat transfer block 4 and heater holding plate 10 are separate members not thermally integrated as in the first to third embodiments, thermal resistance occurs when heat transferred from heater 6 to heater holding plate 10 is transferred to the heat transfer block 4 side as heat flow 22. In the fourth embodiment, heater holding plate 10 is thermally integrated with heat transfer block 4, and plate 1, heat transfer block 4 and heater holding plate 10 are thermally integrated as a whole.

Therefore, thermal resistance in the path along which the heat generated by heater 6 is transferred to plate 1 becomes even smaller than in the third embodiment described above. As a result, the amount of heat transferred from heat transfer block 4 to working fluid 31 through plate 1 to heat working fluid 31 increases, so that thermal responsiveness of the isothermal heating apparatus can further be improved.

Fifth Embodiment

FIG. 12 is a sectional view of an isothermal heating apparatus of a fifth embodiment. The isothermal heating apparatus of the fifth embodiment differs from the fourth embodiment in that a high performance boiling surface 39 which promotes boiling of working fluid 31 is formed on evaporating surface 12 which is the wall surface of header portion 2b of heat pipe circuit 2 on the side where heating means 3 is provided. High performance boiling surface 39 is to promote heat transfer by boiling heat transfer from heating means 3 to plate 1.

Boiling of working fluid 31 is a phenomenon in which a vapor bubble 32 grown from a minute bubble nuclei as an origin in evaporating surface 12 moves away from evaporating surface 12. To promote boiling of working fluid 31, evaporating surface 12 may have a structure whose surface is formed with a large number of minute cavities and minute bubble nuclei are likely to occur. Specifically, high performance boiling surface 39 can be obtained by welding metallic particles onto evaporating surface 12 of plate 1 or groove-processing evaporating surface 12.

By providing such high performance boiling surface 39, working fluid 31 easily boils to become vapor bubbles 32, so that generation of vapor 33 is promoted. In the isothermal heating apparatus of the fifth embodiment, as compared to the first to fourth embodiments, the amount of heat transferred to working fluid 31 can be increased, and the amount of heat transferred to front surface 1a by heat conduction in plate 1 can be reduced. Therefore, heat generated by heater 6 can be utilized for production of vapor 33 still more efficiently, so that thermal responsiveness of the isothermal heating apparatus can further be improved.

Sixth Embodiment

FIG. 13 is a sectional view of an isothermal heating apparatus of a sixth embodiment. Although the first embodiment has been described that branch portions 2a of heat pipe circuit 2 formed in plate 1 have an equal groove depth entirely in the direction that branch portions 2a extend, it is not limited to such a structure. For example, heat pipe circuit 2 may be formed such that the groove depth of branch portions 2a is smaller on the side surface 1d side than on side surface 1c side of plate 1 as shown in FIG. 13.

Then, when horizontally arranging planar plate 1, condensate fluid 34 produced by condensation of vapor 33 in branch portions 2a is more likely to flow along the inclined bottom of branch portions 2a from the side surface 1d side toward the side surface 1c side. Working fluid 31 can thus be easily returned to header portion 2b where working fluid 31 is heated, so that fluid shortage on evaporating surface 12 can be prevented and efficiency of heat pipe circuit 2 can be improved. In addition, since the required amount of working fluid 31 can be reduced, thermal responsiveness of the isothermal heating apparatus can further be improved.

Although, in the descriptions of the first to sixth embodiments, the case where plate 1 is arranged in a horizontal state has been illustrated, the arrangement of plate 1 is not limited to the horizontal state. FIGS. 14 and 15 are sectional views each showing another example of arrangement of plate 1. As shown in FIG. 14, plate 1 may be arranged in the vertically standing state, or plate 1 may be arranged in an inclined state as shown in FIG. 15.

Even when plate 1 is arranged in the vertically standing state or inclined state, it is only necessary to locate heating means 3 on the wall surface side of header portion 2b of heat pipe circuit 2 with which working fluid 31 is in contact when heating means 3 heats the working fluid. Then, the effect of efficiently transferring heat from heating means 3 to working fluid 31 can also be obtained similarly to the above. The structure in which heating means 3 is provided on the rear surface 1b side of plate 1 is not a limitation, but in the isothermal heating apparatus arranged as shown in FIGS. 14 and 15, it is also possible to attach heating means 3 to the side surface 1c side of plate 1.

By arbitrarily combining plates 1 in the horizontal, vertical and inclined states, the isothermal heating apparatus of the present invention can form a duct, a container or the like surrounding space. When a heat-treatment subject is stored in such a duct or a container, the heat-treatment subject can be heated more isothermally.

Seventh Embodiment

FIG. 16 is a plan view of an isothermal heating apparatus of a seventh embodiment. Although, in the description of the first embodiment, the example where heat pipe circuit 2 formed in the inside of plate 1 includes header portion 2b and branch portions 2a processed to extend perpendicularly to header portion 2b and in parallel to one another has been illustrated, such a structure is not a limitation. For example, heat pipe circuit 2 may further include a coupling portion 2d coupling branch portions 2a extending from header portion 2b, as shown in FIG. 16.

Then, the paths of vapor 33 produced by heating of working fluid 31 in header portion 2b increase, so that front surface 1a of plate 1 can be heated more isothermally. If coupling portion 2d is formed so as to couple the tips of branch portions 2a, then, when forming heat pipe circuit 2 by machining, a tool can be moved relative to plate 1 along the loop-like path and perform machining. Therefore, the machining time of processing plate 1 for forming heat pipe circuit 2 can be shortened, and the manufacturing costs of the isothermal heating apparatus can further be reduced.

FIGS. 17 to 19 are plan views of other examples of the isothermal heating apparatus of the seventh embodiment. If heat pipe circuit 2 in the shapes shown in FIGS. 17 and 18 is formed, the effect that can increase the paths of vapor 33 to reduce the manufacturing costs of the isothermal heating apparatus can also be obtained similarly to the structure of FIG. 16. As shown in FIG. 19, if grid-like heat pipe circuit 2 is formed in which a plurality of coupling portions 2d are provided and arranged in parallel to one another, the paths of vapor 33 can further be increased, and front surface 1a of plate 1 can be heated even more isothermally.

In addition, with a structure in which heat pipe circuit 2 is formed along the entire circumference of plate 1 as shown in FIGS. 17 to 19, heating by vapor 33 is conducted on all the side surfaces of plate 1, which can reduce temperature drop that would be caused by heat dissipation from edge. Therefore, thermal uniformity of plate 1 can be improved further as compared to the structure in which heat pipe circuit 2 is not provided partly on the side of an end of plate 1 that is located away from header portion 2b as shown in FIG. 1 or 16.

While the embodiments of the present invention have been described above, the structures of the respective embodiments may be combined as appropriate. It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the claims not by the description above, and is intended to include any modification within the meaning and scope equivalent to the terms of the claims.

INDUSTRIAL APPLICABILITY

The present invention is particularly advantageously applicable to an isothermal heating apparatus that heats a heat-treatment subject, such as an organic material for semiconductor manufacture, into an isothermally heated state.

REFERENCE SIGNS LIST

1 plate; 1a front surface; 1b rear surface; 1c, 1d side surface; 2 heat pipe circuit; 2a branch portion; 2b header portion; 2d coupling portion; 3 heating means; 4 heat transfer block; 4a recess; 5 heat transfer material; 6 heater; 7, 8, 8a interposed member; 9 fixing bolt; 10 heater holding plate; 10a hollowed portion; 12 evaporating surface; 14 contact surface; 21, 22 heat flow; 30 internal space; 31 working fluid; 32 vapor bubble; 33 vapor; 34 condensate fluid; 39 high performance boiling surface; 41 first member; 42 second member; 42a opposed surface.

Claims

1. An isothermal heating apparatus comprising:

a plate having formed therein a heat pipe circuit in which a working fluid is charged; and

heating means heating said working fluid, wherein

said heat pipe circuit includes a header portion at which the working fluid is heated and evaporated and a plurality of branch portions in which vapor produced by vaporization of said working fluid exchanges heat with said plate and condensates, said branch portions branching off from said header portion, and

said heating means is provided on a wall surface side of said header portion with which said working fluid is in contact when said heating means heats said working fluid.

2. The isothermal heating apparatus according to claim 1, wherein

said plate is formed to have a rectangular shape in plan view,

said header portion extends along one side surface of said plate, and

said branch portions are provided to extend toward an other side surface of said plate opposed to said one side surface.

3. The isothermal heating apparatus according to claim 2, wherein said plurality of branch portions are arranged in parallel to one another.

4. The isothermal heating apparatus according to claim 2, wherein said heat pipe circuit further includes a coupling portion coupling said branch portions.

5. The isothermal heating apparatus according to claim 4, wherein said coupling portion couples tips of said branch portions extending from said header portion.

6. The isothermal heating apparatus according to claim 4, wherein a plurality of said coupling portions are provided and are arranged in parallel to one another.

7. The isothermal heating apparatus according to claim 1, wherein said heating means includes a heater, a heat transfer block formed with a recess and storing said heater in said recess, and a heater holding plate holding said heater in said recess.

8. The isothermal heating apparatus according to claim 7, wherein said heating means includes a fixing member fixing said heater holding plate and said heat transfer block integrally to said plate.

9. The isothermal heating apparatus according to claim 7, comprising a thermally conductive interposed member interposed between said plate and said heat transfer block.

10. The isothermal heating apparatus according to claim 7, wherein said heating means includes a thermally conductive interposed member interposed between said heat transfer block and said heater holding plate.

11. The isothermal heating apparatus according to claim 7, wherein said heating means includes a thermally insulative interposed member interposed between said heat transfer block and said heater holding plate.

12. The isothermal heating apparatus according to claim 7, wherein a hollowed portion storing said heater is formed in said heater holding plate at a position opposed to said recess.

13. The isothermal heating apparatus according to claim 1, wherein a high performance boiling surface promoting boiling of said working fluid is formed in said wall surface.

14. The isothermal heating apparatus according to claim 1, wherein a width by which said heating means is in thermal contact with said plate is less than or equal to a width of said wall surface.