JP7445892B2 - Gas phase heating device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas-phase heating device that heats an object to be heated using the latent heat of condensation of a heat transfer liquid.

In recent years, various heat treatment equipment has been used in the assembly manufacturing process of various industrial products or home appliances, or in the manufacturing process of devices such as various electronic components, various batteries, or substrates on which electronic components are mounted. The shapes of objects to be heated are becoming more complex. For example, even on a board with electronic components mounted, not only a flat board but also a three-dimensional board, where the holding force is weak due to applying solder paste to parts other than the horizontal surface of the board and placing the electronic components. Heat treatment is performed to melt and bond the paste. Moreover, by becoming three-dimensional, the heat capacity of the heated object itself tends to increase. Here, the various heat treatment apparatuses include, for example, a drying oven, a curing oven, or a reflow oven used for soldering in the mounting process of electronic components.

In the process of heating the object to be heated, there is variation in temperature rise at each location of the object due to non-uniform heating ability. In such a case, in order to obtain the desired time required for the heating step, it is necessary to maintain the state in which all parts are heated to the desired temperature for a further desired time. At this time, in order to maintain the portion where the temperature rises slowly for a desired time, the portion where the temperature rises quickly is exposed to more heat than necessary. In particular, if the thermal effect is large, there is concern about the impact on quality. In addition, in the case of a heating process that utilizes heat transfer by collision of hot air, if the heat capacity of the object to be heated is large, in order to obtain the desired temperature increase rate, the speed at which the hot air impinges on the object to be heated is increased. Heat transfer coefficient can be increased.

However, for example, if it is necessary to apply heat treatment to parts other than the horizontal plane of a three-dimensional board in a state where the holding force is weak due to simply applying solder paste and arranging electronic components, the melting of the solder and the subsequent By colliding with hot air at high speed before the solder has solidified due to cooling, there is a high possibility that the component will peel off from the board.

Therefore, even for substrates with large heat capacity, as a method to efficiently heat the object by utilizing high heat transfer coefficient and avoiding parts peeling due to collision of hot air, the latent heat of condensation possessed by the vapor of the heat transfer liquid is used. A heating method using a steam heating furnace is known.

The steam used in such a steam heating furnace has a higher specific gravity than air, so the air and steam separate into two phases relatively easily. For this purpose, a steam heating furnace is usually provided with an inlet/outlet, so that the steam easily flows out of the furnace and valuable heat transfer liquid is irretrievably lost.

As described above, the method of Patent Document 1 is known as a method of avoiding outflow of the heat transfer liquid from the entrance/exit for carrying in and out the heated object.

FIG. 11 is an explanatory diagram of a conventional vapor phase soldering apparatus disclosed in Patent Document 1. The configuration disclosed in Patent Document 1 is as follows. The liquid 21 is a heat transfer liquid for generating steam 22 by heating. The inlet 23 and the outlet 24 are an inlet end and an outlet end that serve as boundaries between the inside and outside of the steam heating furnace 28, respectively. The conveyor 25 is a conveyor for carrying the object to be heated into the steam heating furnace 28, and the conveyor 26 is a conveyor for carrying out the object to be heated from the steam heating furnace 28.

When the liquid 21 is heated by the heater 27 to generate steam 22, the steam 22 forms a vapor phase 29 in the steam heating furnace 28. The object to be heated 31 conveyed by the conveyor 25 is lowered into the vapor phase 29 by an elevating body 32 located on the same plane as the conveyor 25 . The object to be heated 31 heated by the latent heat of condensation of the steam 22 is raised by the elevating body 32 to the same plane as the conveyor 26, and is carried out by the conveyor 26.

As the vapor phase 29 rises within the steam heating furnace 28, the vapor 22 is cooled by the cooling coil 30 and condenses into a liquid. Since the cooling coil 30 is provided at a position lower than the inlet 23 and the outlet 24, the vapor phase 29 is held in a region below the inlet 23 and the outlet 24, and can be prevented from flowing out of the furnace.

Japanese Unexamined Patent Publication No. 168276/1983

However, in the configuration of Patent Document 1, although it is possible to prevent the heat transfer liquid from flowing out of the furnace by condensing and liquefying the steam 22 using the cooling coil 30 as described above, it is possible to prevent the heat transfer liquid from flowing out of the furnace. The heat transfer liquid is heated by the heater 27 to give evaporation energy to the heat transfer liquid, while the cooling coil 30 extracts energy from the vapor 22 of the heat transfer liquid in order to liquefy and recover the vapor 22 of the heat transfer liquid. The problem is that energy is required for both heating by the heater 27 and cooling by the cooling coil 30, and the energy consumption of the furnace is extremely large. Further, since the heat transfer liquid condensed and liquefied by the cooling coil 30 is cooled more than necessary to a temperature lower than the boiling point, there is a problem in that the heating energy required to evaporate the heat transfer liquid again becomes large. ing.

The present invention solves the above-mentioned conventional problems, and is capable of maintaining the upper limit height of the vapor phase in the steam heating furnace at a desired position without adding cooling energy, and is capable of maintaining the upper limit of the height of the vapor phase in the steam heating furnace at a desired position. It is an object of the present invention to provide a vapor phase heating device that makes it possible to minimize the energy required for revaporizing a liquid.

In order to achieve the above object, a gas phase heating device according to one aspect of the present invention includes:
a steam tank that holds an object to be heated at an internal heating position, brings vapor of a heat transfer liquid into contact with the object to be heated, and heats the object using latent heat of condensation of the steam;
a heating unit that heats the heat transfer liquid in the steam tank to generate the steam;
a heat transfer liquid recovery section having at least a lower portion installed above the heating position of the object to be heated in the steam tank and below a loading/unloading section of the object to be heated in the steam tank; A phase heating device,
The heat transfer liquid recovery section includes:
The heat transfer liquid is disposed above the heating position of the object to be heated in the steam tank and below the carrying-in/out section of the steam tank, and has a boiling point lower than the boiling point of the heat transfer liquid, and a storage section that stores a heat medium having a boiling point near the boiling point of the transition liquid;
a space communicating with the storage part and extending upward from the storage part to the outside of the steam tank to hold the vapor of the heat medium;
a heat radiating part that is disposed outside the steam tank and outside the space and cools and liquefies the vapor of the heat medium in the space;
and an atmosphere opening section connected to the space section and maintaining the inside of the heat transfer liquid recovery section at atmospheric pressure.

As described above, according to the vapor phase heating device of the above aspect of the present invention, the heat transfer liquid recovery section is provided, and the heat medium stored in the storage section is vaporized by the latent heat of condensation of the vapor of the heat transfer liquid. By doing this, the vapor of the heat transfer liquid can be liquefied and recovered at a temperature above the boiling point of the heat transfer medium and below the boiling point of the heat transfer liquid, and the heat transfer liquid that has been liquefied and recovered at a temperature above the boiling point of the heat transfer medium is heated to the boiling point again. It becomes possible to suppress the energy required for heating. Moreover, it becomes possible to liquefy and recover the heat transfer liquid without circulating and cooling the cooling liquid. As a result, the energy required to heat the heat transfer liquid and the energy required to liquefy and recover the vapor of the heat transfer liquid can be reduced.

An explanatory diagram seen from the front of a vapor phase heating device in an embodiment of the present invention An enlarged sectional view of a heat insulating material portion of a vapor phase heating device in an embodiment of the present invention An explanatory diagram seen from the side of a vapor phase heating device in an embodiment of the present invention A diagram showing step-by-step how the vapor phase heating device is used in an embodiment of the present invention. A diagram showing step-by-step how the vapor phase heating device is used in an embodiment of the present invention. A diagram showing step-by-step how the vapor phase heating device is used in an embodiment of the present invention. A diagram showing step-by-step how the vapor phase heating device is used in an embodiment of the present invention. A diagram showing step-by-step how the vapor phase heating device is used in an embodiment of the present invention. A diagram showing step-by-step how the vapor phase heating device is used in an embodiment of the present invention. A diagram showing step-by-step how the vapor phase heating device is used in an embodiment of the present invention. An explanatory diagram of changes in steam height in the configuration of a vapor phase heating device according to an embodiment of the present invention An explanatory diagram of temperature distribution of a heat transfer liquid and a heat medium in an example of an embodiment of the present invention An explanatory diagram of the temperature distribution of the steam of the heat transfer liquid and the heat medium in an example of the embodiment of the present invention Explanatory diagram of a conventional gas phase heating device

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment)
FIG. 1A is an explanatory diagram of a vapor phase heating device in an embodiment of the present invention.

The gas phase heating device 1 includes at least a steam tank 2, a heating section 4, and a heat transfer liquid recovery section 9.

The steam tank 2 forms a vapor phase 7 from above the liquid surface of the heat transfer liquid 3, and objects to be heated 5 are carried into the steam tank 2 from a carry-in/out section 6, and the objects to be heated 5 are placed at internal heating positions 8. The vapor of the heat transfer liquid 3 is brought into contact with the object to be heated 5, and the object to be heated 5 is heated using the latent heat of condensation of the vapor. Between the loading/unloading section 6 and the heating position 8 inside the steam tank 2, the object to be heated 5 is raised and lowered by a known lifting device 17 or the like.

The heating unit 4 includes, for example, a heater, and heats the heat transfer liquid 3 stored in the lower part of the steam tank 2 to generate steam.

At least a lower portion of the heat transfer liquid recovery unit 9 is disposed in the steam tank 2, and condenses the vapor of the heat transfer liquid 3 to liquefy and recover it.

As a method of heating the object to be heated 5, a vapor phase 7 of the heat transfer liquid 3 is formed in the steam tank 2 by preheating the heat transfer liquid 3 in the heating section 4 in the steam tank 2.

Thereafter, the heated object 5 carried into the steam tank 2 from the carry-in/out section 6 is held at a heating position 8 in the vapor phase 7, and the vapor of the heat transfer liquid 3 imparts condensation latent heat to the heated object 5. It is configured so that the object to be heated 5 is heated.

Here, in order to prevent the vapor phase 7 formed by heating the heat transfer liquid 3 in advance from flowing out of the steam tank 2 from the carrying-in/out section 6 of the heated object 5, the vapor-phase heating device 1: A heat transfer liquid recovery section 9 is provided for condensing and liquefying the vapor of the heat transfer liquid 3.

The heat transfer liquid recovery section 9 is a pair of rectangular parallelepiped box-shaped members arranged opposite to each other inside the side wall of the steam tank 2 along the conveyance direction, and includes a storage section 15, a space section 12, and a heat dissipation section. It is configured to include a section 13 and an atmosphere opening section 14. The heat transfer liquid recovery section 9 is not limited to a pair, and may be either one.

The storage section 15 is arranged in the steam tank 2 above the heating position 8 of the object to be heated 5 and below the loading/unloading section 6 for carrying the object to be heated 5 into and out of the steam tank 2. There is. Further, the storage section 15 stores a heat medium 10 having a boiling point lower than the boiling point of the heat transfer liquid 3 and a boiling point near the boiling point of the heat transfer liquid 3 in the lower part.

The space portion 12 communicates with the storage portion 15 , extends upward from the storage portion 15 to the outside of the steam tank 2 , and holds the steam 11 of the heat medium 10 . It is preferable that the space 12 has a heat insulating structure in order to suppress heat radiation (for example, to keep the steam 11 warm). As an example of a heat insulating structure, as shown in FIG. 1B, a heat insulating material 18 may be placed outside the space 12 to keep the vapor of the heat medium 10 warm in order to suppress heat radiation in the space 12. Alternatively, the material constituting the space 12 itself may be made of a material with very high heat insulation properties (in other words, low thermal conductivity). Alternatively, the space 12 may have a double wall structure to create a vacuum between the outer wall and the inner wall.

As shown in FIGS. 1A to 1C, the heat dissipation section 13 is a heat dissipation section that is outside the steam tank 2 and laterally extends around the outside of the upper end of the space section 12 and extends in the vertical direction (for example, the vertical direction). It is composed of a plate 13a, and cools and liquefies the vapor 11 of the heat medium 10 in the space 12. The liquefied heat medium 10 falls within the space 12 and is stored in the storage section 15 .

The atmosphere opening section 14 is a tube that is connected to the upper end of the space section 12, extends further upward from the end surface of the upper end, and is opened to the atmosphere, and maintains the inside of the heat transfer liquid recovery section 9 at atmospheric pressure.

An example of the heat transfer liquid and the heat medium are electrically insulating fluorine-based inert liquids having different boiling points.

A method for recovering the vapor of the heat transfer liquid 3 in the heat transfer liquid recovery section 9 will be explained using FIGS. 2 to 5.

FIG. 2 shows the step of generating steam of the heat transfer liquid 3 for heating the object to be heated 5 in the steam tank 2. As shown in FIG. In the steam tank 2, the heat transfer liquid 3 that has reached its boiling point is heated by the heating section 4, whereby the heat transfer liquid 3 is vaporized and steam is generated. Since the vapor of the heat transfer liquid 3 has a higher specific gravity than air, the vaporized vapor forms a vapor phase 7 from above the liquid surface of the heat transfer liquid 3 in the steam tank 2 (this is referred to as state A).

In state A shown in FIG. 2, by further continuing to heat the heat transfer liquid 3, the upper limit height of the vapor phase 7 in the steam tank 2 increases, and as shown in FIG. reaches the storage section 15 (this is referred to as state B).

FIG. 4 shows the state after the vapor phase 7 reaches the storage section 15. A heat medium 10 having a boiling point lower than that of the heat transfer liquid 3 is stored in the storage section 15 . When the vapor of the heat transfer liquid 3 contacts the storage part 15, the vapor of the heat transfer liquid 3 condenses and liquefies, and the vapor of the heat transfer liquid 3 gives latent heat of condensation to the heat medium 10 stored in the storage part 15. . The temperature of the heat medium 10 given the latent heat of condensation increases, and after reaching the boiling point, it vaporizes and becomes steam 11. The vapor 11 of the vaporized heat medium 10 is retained in the space 12 (this is referred to as state C).

In the state shown in FIG. 5, as the heat medium 10 is intermittently vaporized, the steam 11 flowing from the space 12 into the heat radiation part 13 is caused by the temperature difference between the temperature of the steam 11 and the ambient temperature of the heat radiation part 13. It is cooled, condensed and liquefied, and stored again in the storage section 15 (this is referred to as state D). At this time, the heat is radiated so that the amount m ₁ per unit time in which the steam 11 condenses and liquefies in the heat radiating section 13 and the amount m ₂ per unit time in which the heat medium 10 evaporates and vaporizes satisfy m ₁ ≧ m ₂ . By designing the section 13 in advance, the steam 11 does not pass through the atmosphere opening section 14 and flow out to the outside. That is, in state D, when (the amount of evaporation of the heat medium)>(the amount of condensation and liquefaction at the heat radiation section), the vapor of the heat medium 10 overflows from the atmosphere opening section 14 to the outside. In order to prevent this, the heat radiation part 13 is designed in consideration of the material, area, thickness, etc. of the heat radiation plate 13a.

In this way, by using the latent heat of condensation of the vapor of the heat transfer liquid 3 as the latent heat of vaporization of the heat transfer medium 10 in the heat transfer liquid recovery section 9, the vapor of the heat transfer liquid 3 can be heated to a temperature higher than the boiling point of the heat transfer medium 10 and The liquid can be liquefied and recovered at a temperature below the boiling point of the liquid 3, making it possible to suppress the energy input to the heating section 4.

Next, when the object to be heated 5 is carried into the heating position 8 in the vapor phase 7 and the object to be heated 5 is heated at the heating position 8, the vapor of the heat transfer liquid 3 and the vapor of the heat medium 10 11 We will explain the behavior of

FIG. 6 shows the vapor phase 7 and the heat transfer liquid recovery section 9 immediately after the heated object 5 is introduced into the vapor phase 7. In state D described above, the object to be heated 5 is carried in from the carry-in/out section 6 and is held at the heating position 8 below the carry-in/out section 6 . At this time, the steam in the vapor phase 7 is consumed to heat the object 5 to be heated, and the upper limit height of the vapor phase 7 is the height of the object 5 at the heating position 8 from the height at which it reaches the storage section 15. It will temporarily drop. Immediately after the object to be heated 5 is carried into the heating position 8, the heat transfer liquid recovery section 9 sufficiently retains the steam 11 in the space 12 (this is set as state E). When the object to be heated 5 is heated for a predetermined period of time at the heating position 8, the object to be heated 5 is carried out from the carry-in/out section 6, and becomes in a standby state until the next object to be heated 5 is carried in.

FIG. 7 shows that the vapor of the heat transfer liquid 3 is consumed by heating the object 5 to be heated, and the upper limit height of the vapor phase 7 temporarily falls to the height of the object 5 at the heating position 8, and then rises again. It represents the state of progress. When the vapor of the heat transfer liquid 3 is consumed and the height of the upper limit of the vapor phase 7 becomes lower than the bottom of the storage section 15, the heat will continue until the height of the upper limit of the vapor phase 7 reaches the storage section 15 again. The vapor of the transition liquid 3 cannot impart latent heat of condensation to the heat medium 10. During this period, the heat medium 10 does not vaporize, and the steam 11 held in the space 12 condenses and liquefies, so the amount of steam 11 decreases and the upper limit height of steam 11 also decreases (this is referred to as state F). At this time, by using a heat medium whose specific gravity is higher than that of air, the steam 11 is held below the space part 12 in state F, and the heat is stored in the storage part 15 without being condensed and liquefied in the heat radiation part 13. It condenses and liquefies on the liquid surface of the medium 10. Thereby, the heat medium 10 is given latent heat of condensation from the steam 11 and is kept at its boiling point. In addition, in order to keep the heat medium 10 warm in state F, the upper limit height of the vapor phase 7 is increased again in the storage part 15 from the state E where the upper limit height of the vapor phase 7 is lowered in the space part 12. It is necessary to maintain the amount of steam that continues to condense on the liquid surface of the heat transfer medium 10 in the space 12 until reaching the temperature. For this purpose, the amount of vapor of the heating medium is If all the vapor in the space 12 is condensed before the upper limit of the vapor in the heat transfer liquid 3 reaches the heat transfer liquid recovery section 9, the temperature of the heat medium 10 in the storage section 15 will drop from its boiling point. In order to prevent this, it is necessary to maintain a sufficient amount of steam in the space 12. Therefore, the retained amount may be determined from the evaporation rate of the heat transfer liquid 3, the size of the vapor phase 7, the physical properties of the heat transfer liquid 3, the condensation rate of the vapor of the heat transfer medium 10, the physical properties of the heat transfer medium 10, etc.

FIG. 8 shows that the vapor of the heat transfer liquid 3 is consumed by heating the object to be heated 5, and the upper limit height of the vapor phase 7 decreases, then rises again, and the upper limit height of the vapor phase 7 increases to the storage part 15. It represents the state that has been reached. When the upper limit height of the vapor phase 7 reaches the storage section 15 again, the vapor of the heat transfer liquid 3 imparts latent heat of condensation to the heat medium 10 in the storage section 15 and is condensed and liquefied. This is the same state as state C mentioned above. Thereafter, the vapor of the heat transfer liquid 3 repeats condensation and liquefaction, resulting in state D shown in FIG. 5, and waits for the next object to be heated 5 to be carried in.

Before the object to be heated 5 is introduced into the vapor phase 7, the vapor of the heat transfer liquid 3 and the vapor 11 of the heat medium 10 change in the order of states A, B, C, and D. When the object to be heated 5 is carried in in state D and heating is started, the vapor of the heat transfer liquid 3 and the vapor 11 of the heat medium 10 change to states E and F, then go through state C and return to state D again. . Every time the object to be heated 5 is carried in and carried out repeatedly, the vapor of the heat transfer liquid 3 and the vapor 11 of the heat medium 10 repeat changes in states D, E, F, C, and D. FIG. 9 shows changes in the upper limit heights of the vapor of the heat transfer liquid 3 and the vapor 11 of the heat medium 10 in states A to F.

As one specific example of the embodiment of the present invention, a heat transfer liquid with a boiling point of 240° C., for example, is used as the heat transfer liquid 3, and a heat transfer medium with a boiling point of 200° C., for example, is used as the heat medium 10. Then, the temperature of the heat transfer liquid 3 liquefied and recovered in the heat transfer liquid recovery section 9 becomes 200° C. or higher, which is the boiling point of the heat transfer medium 10. In order to raise the temperature of the heat transfer liquid 3 that has been liquefied and recovered to the boiling point again, energy corresponding to a maximum temperature difference of 40°C may be applied to the heat transfer liquid 3 from 200°C to 240°C. For example, when a heat medium with a boiling point of 230° C. is used as the heat transfer medium 10, the temperature of the heat transfer liquid 3 liquefied and recovered in the heat transfer liquid recovery section 9 will be equal to or higher than the boiling point of the heat transfer medium 10, which is 230°C. In order to raise the temperature of the heat transfer liquid 3 that has been liquefied and recovered to the boiling point again, energy corresponding to a maximum temperature difference of 10°C may be applied to the heat transfer liquid 3 from 230°C to 240°C. The boiling point of the heat transfer medium 10 is a temperature at which the vapor of the heat transfer liquid 3 can be liquefied and recovered, and it is preferable that the boiling point is closer to the boiling point of the heat transfer liquid 3.

As shown in FIG. 10A, the heat transfer liquid 3 and the heat medium 10 have a temperature distribution around a certain temperature and a boiling point. However, even if there is a temperature distribution in the boiling point, as shown in FIG. The vapor of the low boiling point component of the liquid 3 does not condense in the lower part of the storage section 15 because the boiling point of the heat transfer medium 10 is higher, but it condenses in the upper part of the storage section 15 where the low boiling point component of the heat transfer medium 10 is stored. Therefore, the vapor of the heat medium 10 is liquefied and recovered.

Since the temperature distribution of the boiling points of the heat transfer liquid 3 and the heat transfer medium 10 is about ±10°C, it is sufficient that the boiling point of the heat transfer medium 10 is about 10°C below the boiling point of the heat transfer liquid 3.

The present invention is not limited to the above-mentioned heat transfer liquid having a boiling point of 240° C., and embodiments of the present invention can be realized by using a heat medium 10 corresponding to the boiling point of the heat transfer liquid 3.

According to the embodiment, the heat transfer liquid recovery unit 9 is provided, and the heat transfer liquid 3 vapor is vaporized by vaporizing the heat medium 10 stored in the storage unit 15 using the latent heat of condensation of the vapor of the heat transfer liquid 3. can be liquefied and recovered at a temperature above the boiling point of the heat medium 10 and below the boiling point of the heat transfer liquid 3. In addition, by condensing and liquefying the vapor 11 of the heat medium 10 vaporized in the heat transfer liquid recovery unit 9 in the heat radiation unit 13, heat can be generated without adding cooling energy, or in other words, without circulating or cooling the cooling liquid. The vapor of the transition liquid 3 can be liquefied and recovered. As a result, the energy required to raise the temperature of the heat transfer liquid 3 liquefied and recovered at a temperature higher than the boiling point of the heat medium 10 to the boiling point again can be suppressed, and the running cost of the gas phase heating device 1 can be reduced. It can be realized.

Note that by appropriately combining any of the various embodiments or modifications described above, the effects of each can be achieved. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features in different embodiments or examples are also possible.

The vapor phase heating device according to the above aspect of the present invention can liquefy and recover the vapor of the heat transfer liquid without applying cooling energy. Therefore, the above aspect of the present invention is applicable to a drying oven, a curing oven, or a reflow oven in the manufacturing process of industrial products or home appliances or the manufacturing process of various electronic components as an apparatus capable of performing heat treatment at low running cost. It can be applied to heat treatment equipment that performs various heat treatments such as.

1 Gas phase heating device 2 Steam tank 3 Heat transfer liquid 4 Heating section 5 Object to be heated 6 Carrying in/out section 7 Steam phase 8 Heating position 9 Heat transfer liquid recovery section 10 Heat medium 11 Steam 12 Space section 13 Heat dissipation section 13a Heat dissipation plate 14 Atmospheric release part 15 Storage part 17 Elevating device 18 Insulating material 21 Liquid 22 Steam 23 Inlet 24 Outlet 25 Conveyor 26 Conveyor 27 Heater 28 Steam heating furnace 29 Steam phase 30 Cooling coil 31 Object to be heated 32 Elevating body

Claims (3)

a steam tank that holds an object to be heated at an internal heating position, brings vapor of a heat transfer liquid into contact with the object to be heated, and heats the object using latent heat of condensation of the steam;
a heating unit that heats the heat transfer liquid in the steam tank to generate the steam;
a heat transfer liquid recovery section having at least a lower portion installed above the heating position of the object to be heated in the steam tank and below a loading/unloading section of the object to be heated in the steam tank; A phase heating device,
The heat transfer liquid recovery section includes:
The heat transfer liquid is disposed in the steam tank above the heating position of the object to be heated and below the carrying-in/out section of the steam tank, and has a boiling point lower than the boiling point of the heat transfer liquid, and a storage section that stores a heat medium having a boiling point near the boiling point of the transition liquid;
a space communicating with the storage part and extending upward from the storage part to the outside of the steam tank to hold the vapor of the heat medium;
a heat radiating part that is disposed outside the steam tank and outside the space and cools and liquefies the vapor of the heat medium in the space;
A gas phase heating device comprising: an atmosphere opening section connected to the space section and maintaining the inside of the heat transfer liquid recovery section at atmospheric pressure. The vapor phase heating device according to claim 1, wherein the space has a heat insulating structure. The vapor phase type according to claim 1 or 2, wherein the heat radiating part has a heat radiating plate that is outside the steam tank and laterally extends around the outside of the upper end of the space part and extends in the vertical direction. heating device.

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