JPS62148082A - Vapor reflow type soldering device - Google Patents

Abstract

PURPOSE:To realize the reduction of a running cost, etc., by providing the liquid mist generating means of a low temperature heating medium on a carrying-out side carrying path, and also bringing the heating value of a heating medium which becomes a high temperature, to a heat recovery to preheating of an object to be treated. CONSTITUTION:A liquid mist generating means for cooling an object to be treated 13 which is soldered is constituted by providing an upper liquid nozzle 24 and a lower liquid nozzle 25, on the upper wall of a carrying-out side carrying path 3, and the lower wall, respectively. The object to be treated 13 which is soldered by the saturated vapor 12 of a heating medium in a vapor tank 1 is cooled by the liquid-shaped curtain of the nozzles 24, 25 of the carrying-out side carrying path 3. In this case, the heating medium which takes away heat from the object to be treated 13 is fed to the heat exchanger 19 of the air curtain device 15 of a carrying in side carrying path 2 and cooled. The saturated vapor 12 is sealed by the liquid-shaped curtain and the air curtain device 15, and its leakage to the outside is reduced. The consumption of an expensive heating medium is decreased, and the running cost is reduced and the safety can be improved.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a vapor reflow soldering device,
A vapor reflow solder suitable for soldering printed wiring boards, especially high-density mounted printed wiring boards using semiconductor chip parts such as so-called flat pack elements, resistors, capacitors, etc., in which electrode terminals are taken out in a flat manner in four directions. The present invention relates to a mounting device.

[Background of the invention]

In recent years, the high-density mounting of electronic components on printed wiring boards has become more and more advanced, but since the soldering process for bonding electronic components such as semiconductor chips to printed wiring boards is the final process on the line, the quality of the soldering depends on the electronics. Soldering technology has come to be seen as the most important technology on the line because it affects the performance of parts.

Recently, due to the need to improve the uniformity of temperature distribution in the furnace where soldering work is carried out and to avoid harmful overheating of electronic components, steam with a high density relative to air has been used as a heat medium and its latent heat of condensation has been utilized. Paper reflow (steam remelting) type soldering equipment, which heats the workpiece using steam, is attracting attention.

This device, as described in Japanese Patent Application Laid-Open No. 60-106502, mounts electronic components on the solder pattern of a printed wiring board, and as described above, this printed wiring board is saturated with a heat medium having a high specific gravity relative to air. This is a soldering device equipped with a vapor tank called a vapor reflow tank, which heats and melts solder by passing it through steam to solder electronic components onto printed wiring boards.

The heat carrier used in such a steam tank is a fluorine thread inert organic agent, etc., and the saturated steam has a specific gravity relative to air, such as a molecular weight of about 820 grams per mole under the applied temperature and pressure. In some cases, the amount is about 20 times greater. As described above, heat carriers are very expensive, and various recovery devices have been devised to recover used steam for reuse.

First, a typical conventional horizontal vapor reflow soldering apparatus using a belt conveyor will be described with reference to FIG.

FIG. 8 is a configuration diagram of a conventional vapor reflow soldering apparatus.

In FIG. 8, reference numeral 1 denotes a steam tank in which a steam generation tank 1a for boiling and heating the heat medium 11 and a furnace tank section for heating and melting the solder of the workpiece are integrated, and 2' is a steam tank for heating the workpiece. 3' is a carry-in side conveyance path for carrying the soldering members 13 into the steam tank 1, and 4 is a conveyor for conveying the soldered members 13.

5 is a heater provided at the lower part of the steam tank 1, that is, the steam generation tank 1a section; 6 is an upper cooling coil provided at the upper part of the steam tank 1; and 7 is a heater provided at the outer periphery of the carry-in conveyance path 2'. Reference numeral 8 designates a carry-in side cooling coil, 8 a carry-out side cooling coil provided on the outer periphery of the carry-out conveyance path 3', 9 an carry-in side exhaust port, and 10 a carry-out side exhaust port.

The operation of the vapor reflow soldering apparatus configured as described above will be explained.

The saturated steam 12 of the heat medium evaporated by the heater 5 immersed in the heat medium 11 stored at the bottom of the steam tank 1, that is, the steam generator, rises to the top of the steam tank 1, and its height is equal to that of the upper cooling. It is controlled by the condensing action of the coil 6.

The saturated steam 12 flowing into the carry-in side conveyance path 2' and the carry-out side conveyance path 3' is cooled by the carry-in side cooling coil 7 and the edge-side cooling coil 8, and the amount of steam gradually decreases. A small amount of remaining steam is exhausted to the atmosphere from the carry-in side exhaust port 9 and the carry-out side exhaust port 10.

On the other hand, the object to be processed, that is, the soldering member 13, is used to solder electronic components to a printed wiring board.

It is carried into the carry-in side conveyance path 2' by the conveyor 4, is gradually heated by contacting the saturated steam 12, and enters the steam tank 1.
The solder is heated and melted by the latent heat of condensation of the saturated steam 12, and the components are soldered together.

At this time, a part of the saturated steam 12 condenses and liquefies and falls.
It accumulates in the lower part of the steam tank 1, that is, in the lower part of the steam generation tank 1a.

The soldered members 13 that have been processed are transferred to the unloading conveyance path 3'.
It is gradually cooled down and removed from the equipment.

In such a vapor reflow soldering apparatus, the following problems occur.

1) A conveyor 4 passes through the entrance and exit 11 of the conveyance path, and in order to transport the soldering member 13, which is the object to be processed, in and out.
An opening is absolutely necessary. For this reason, the saturated steam 12 of the heating medium leaks into the atmosphere from the opening.

Heat carriers are generally extremely expensive, so leakage of saturated steam will increase running costs, and there is also a safety issue as heat carriers contain a small amount of toxic and corrosive gas in their steam. becomes.

2) The soldering members 13 that have been soldered in the steam tank 1 are cooled by heat transfer from the air contained in the steam in the delivery path 3 and radiant heat transfer to the cooled transport path. However, since these have a small amount of heat transfer, the discharge side conveyance path 3, that is, the cooling path becomes long.

Therefore, it takes a long time to transport the solder on the soldering member 13 until it hardens, and during that time there is a risk that the soldering location may move due to the vibration of the conveyor 4 or the influence of the steam flow. For this reason, there are limits to the amount of soldering work,
On the other hand, there is a problem in that the output conveyance path 3 is elongated, resulting in an increase in the size of the soldering apparatus as a whole.

[Purpose of the invention]

The present invention has been made in order to solve the problems of the prior art described above, and it efficiently cools the workpiece after soldering, and uses a heated heat medium to cool the soldered part. The purpose of the present invention is to provide a vapor reflow soldering device that recovers heat for preheating a workpiece and reduces leakage of saturated steam as a heating medium, has low running costs, and is highly reliable.

[Summary of the invention]

The configuration of the vapor reflow soldering apparatus according to the present invention includes a steam tank in which saturated steam as a heating medium is brought into contact with the workpiece to heat and melt the solder on the workpiece, and a soldering process is carried out by heating and melting the solder on the workpiece. In a steam-heating soldering apparatus equipped with a conveyance path for carrying in and out the workpiece, a means for generating a liquid mist of a low-temperature heat medium is provided in the carry-out side conveyance path for cooling the workpiece after soldering. The high-temperature heat medium heated to a high temperature as the object to be processed is cooled will be explained with reference to the means for preheating the object to be processed in the carry-in conveyance path.

First, FIG. 1 is a configuration diagram of a vapor reflow soldering apparatus according to an embodiment of the present invention, and FIG.
-A is a sectional view taken along arrow A, and in the figure, the same reference numerals as those in FIG. 8 are the same parts as in the prior art, so the explanation thereof will be omitted.

The embodiment shown in FIGS. 1 and 2 is an example in which a heat medium liquid mist generating means is provided in the carry-out conveyance path, and an air curtain device is installed at the opening of the carry-in conveyance path to recover heat.

FIG. 2 shows details of the air curtain device 15 installed at the entrance opening 14 of the carry-in conveyance path 2.

In FIG. 2, 16 is a discharge nozzle that blows out a circulating air flow forming an air curtain, 17 is a suction nozzle that sucks in the air flow, 18 is a fan with an electric motor that generates the circulating air flow, and 19 is a circulating air This is a heat exchanger for exchanging heat with a high-temperature heat medium generated by acid mist generation of the heat medium in the carry-out conveyance path 3, which will be described later.

21 is a duct for air circulation that communicates the heat exchanger 19 and the discharge nozzle 16, and 22 is a duct for air circulation that communicates the suction nozzle 17 and the motorized fan 18 installation part.

24 is an upper liquid nozzle related to a spray nozzle provided on the upper wall of the carry-out side conveyance path 3; 25 is a lower liquid nozzle related to a squirt nozzle provided on the lower wall of the carry-out side conveyance path 3; these upper liquid nozzles 24. The lower liquid nozzle 25 constitutes a low-temperature heat medium liquid generating means for cooling the soldering member 13 after soldering. That is, the upper liquid nozzle 24. A low temperature heat transfer liquid is ejected from the lower liquid nozzle 25 to form a liquid curtain.

Note that the heat medium for generating acid mist used in this embodiment is the same type as the heat medium 11 for heating solder for performing soldering in a steam bath.

Reference numeral 26 denotes a discharge-side liquid reservoir that receives the heat medium liquid that has become high temperature as the soldering member 13 is cooled by a liquid curtain, 27 a circulation pump, and 28' a circulation pump 2.
A pipe 29' is a pipe related to a heat medium circulation path and connects the discharge side liquid reservoir 26 and the heat exchanger 19 of the air curtain device 15, and a pipe 29' is a pipe related to a heat medium circulation path provided with a heat medium circulation path. Exchanger 19 and upper liquid nozzle 24. This is a pipe that connects to the lower liquid nozzle 25.

The operation of the vapor reflow soldering apparatus of this embodiment having such a configuration will be explained.

When the soldering member 13 related to the workpiece that has been heated by the saturated steam 12 of the heat medium in the steam tank 1 and soldered by remelting the solder enters the discharge side conveyance 16I3,
It is cooled by a liquid curtain of low temperature heat transfer medium formed by the upper liquid nozzle 24 and the lower liquid nozzle 25. The heat medium that has taken heat from the soldering member 13 rises in temperature and accumulates in the discharge side liquid reservoir 26.

This high-temperature heat transfer liquid is sent by the circulation pump 27 via the piping 28' to the heat exchanger 19 of the air curtain device 15 installed at the opening 14 of the carry-in conveyance path 2, and is caused by the circulating air flow of the air curtain. cooled down.

The cooled low-temperature heat transfer liquid is delivered to the liquid mist generating means, that is, the upper liquid nozzle 24 in the discharge side conveyance path 3 via the pipe 29'.
．． Returning to the lower liquid nozzle 25, the circulation is repeated.

On the other hand, in the air curtain device 15, the circulating air flow heated by the heat exchanger 19 passes through the duct 21 to the discharge nozzle 1.
6 and is rectified and accelerated to form an air curtain in front of the artificial opening 14 of the carry-in side conveyance path 2, thereby heating the soldering member 13 being conveyed through the carry-in side conveyance path 2. This heating functions as preheating before the soldering member 13 is subjected to heat treatment in the evaporation tank 1.

The air whose temperature has decreased is sucked into the suction nozzle 17,
It passes through the duct 22, is accelerated and pressurized by the motorized fan 18, and is repeatedly circulated.

According to this embodiment, the following effects are achieved.

1) After the soldering member 13 related to the workpiece is heated to the melting point of the solder with the saturated steam 12 of the heating medium, it is suddenly cooled to below the freezing point with the low-temperature heating medium, so the electronic component with heat capacity is It does not reach the melting point of solder, so there is little thermal influence. In addition, an unloading conveyance path 3 provided downstream thereof
The length of the device may be short, resulting in an economically advantageous compact device.

2) The liquid curtain blocks the conveyance path, and the temperature of the liquid curtain is lower than the saturated steam 12, so the steam flowing from the steam 4!1 to the discharge side conveyance path is the low-temperature heat medium forming the liquid curtain. Condenses into liquid.

Therefore, there is a sealing effect against the saturated heat medium steam 12, the leakage of heat medium vapor from the soldering device to the atmosphere is reduced, the consumption of expensive heat medium is reduced, and running costs are reduced and safety is improved. can be achieved.

3) Since the heat medium heated as the soldering members 13 in the carry-out conveyance path 3 are cooled is recovered for preheating the soldering members 13 in the carry-in conveyance path 2, energy saving can be achieved.

Next, another embodiment of the present invention will be described with reference to FIG.

Here, FIG. 3 is a block diagram of a vapor reflow soldering apparatus according to another embodiment of the present invention. In the figure, the same reference numerals as in FIG. 1 are the same parts as in the previous embodiment. , the explanation thereof will be omitted.

The embodiment shown in Fig. 3 shows an example in which a liquid curtain is provided on the carry-out side and heat is recovered by the liquid curtain on the carry-in side. Instead of the device 15, a mist generating means is provided.

In FIG. 3, 30 is an upper liquid nozzle related to the spray nozzle provided on the earthen wall of the carry-in side conveyance path 2, 31 is a lower liquid nozzle related to the spray nozzle provided on the lower wall of the carry-in side conveyance path 2,
The upper liquid nozzle 30° and the lower liquid nozzle 31 constitute a liquid mist generating means of a high temperature heat medium for preheating the soldering member 13. That is, the upper liquid nozzle 30. A high temperature heat transfer liquid is ejected from the lower liquid nozzle 31 to form a liquid curtain.

Note that the heat medium for generating the liquid curtain used in this embodiment is the same type as the heat medium 11 for heating solder for performing soldering in the steam bath 1.

Reference numeral 32 designates an inlet-side liquid reservoir that receives the heat medium liquid that has become low temperature as the soldering member 13 is preheated by the liquid curtain, and 33 represents a cooling circulation pump.

In addition, 28 is piping related to a heat medium circulation path equipped with a circulation pump 27, which connects a liquid reservoir 26 on the carry-out side and an upper liquid nozzle 30 on the carry-in side. The pipe 29 connecting the lower liquid nozzle 32 is a pipe related to a heat medium circulation path equipped with a cooling circulation pump 33, and connects the liquid reservoir 32 on the carry-in side and the upper liquid nozzle 24 on the carry-out side. This is a pipe that connects to the lower liquid nozzle 25.

The high-temperature heat medium accumulated in the carry-out side liquid reservoir 26 that has been heated by the cooling of the soldering parts 13 and the saturated steam from the steam tank 1 is transferred to the upper part of the carry-in side conveying path 2 via the piping 28 by the circulation pump 27. Liquid nozzle 30. The liquid is sent to the lower liquid nozzle 31 and sprayed into the carry-in conveyance path 2 to form a liquid curtain.

The low-temperature heat medium liquid, whose temperature has been lowered by preheating the soldering member 13 by the liquid curtain, accumulates in the carry-in side liquid reservoir 32, and is sent to the upper liquid provided in the carry-out side conveyance path via the piping 29 by the cooling circulation pump 33. Nozzle 24. Lower liquid nozzle 25
and the cycle repeats.

According to the embodiment shown in FIG. 3, the same effects as those described in the embodiments shown in FIGS. 1 and 2 can be expected, and the soldering member 1
Since preheating and cooling in step 3 are performed simultaneously from the soil wall and the lower wall of the conveyance path, thermal deformation of the soldering member due to temperature difference can be minimized, and the reliability of the soldering member 13 can be increased. .

Next, still another embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a configuration diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention, and in the figure, the third
Components with the same reference numerals as those in the drawings are the same parts as those in the embodiment of FIG. 3, so the explanation thereof will be omitted.

The embodiment shown in FIG. 4 shows an example in which two stages of liquid curtains having different temperatures are provided on the carry-out side, and heat is recovered at different temperatures by the two stages of liquid curtains on the carry-in side.

In FIG. 5, 34 is an upper liquid nozzle related to the spray nozzle provided on the earthen wall of the carry-out side conveyance path 3, and 35 is a lower liquid nozzle related to the spray nozzle provided on the lower wall of the carry-out side conveyance path 3. ,
These constitute the second mist generation means for the low-temperature heat medium. That is, the upper liquid nozzle 24 constituting the first liquid mist generating means. A second liquid curtain having a different temperature from the liquid curtain spouted from the lower liquid nozzle 25 is formed.

36 is a discharge side liquid reservoir, 37 is a second circulation pump, and 38 is a pipe related to a heat medium circulation path.

On the other hand, 39 is an upper liquid nozzle related to the spray nozzle provided on the upper wall of the carry-in side conveyance path 2, and 40 is a lower liquid nozzle related to the spray nozzle provided on the lower wall of the carry-in side conveyance path 3. It constitutes a second liquid mist generating means for the heating medium. That is, the upper liquid nozzle 30. which constitutes the first preheating means for the object to be treated. The liquid curtain spouted from the lower liquid nozzle 31 forms a second preheating means having a different temperature.

41 is a liquid reservoir on the carry-in side, 42 is a second cooling circulation pump,
43 is piping related to the heat medium circulation path.

The apparatus of the embodiment shown in FIG. 4 has a second liquid curtain provided on each of the 9 m inlet and outlet sides of the apparatus shown in FIG. 3, and its two functions need not be particularly explained.

According to the embodiment shown in FIG. 4, the same effects as those of the above-mentioned embodiments are expected, and by employing two stages of liquid curtains with different temperature levels, the soldering member 13 can be preheated, It becomes possible to provide ideal temperature changes on both sides of the cooling process, and it is possible to improve the quality of soldering and the reliability of soldered parts.

It should be noted that it is easy to think of providing the liquid curtain in more stages, and the two functions of the device configuration are the same, and the number of stages of the liquid curtain is a design issue, so illustrations and explanations for multi-stages of three or more stages will be omitted. do.

Next, still another embodiment of the present invention will be described with reference to FIGS. 5 and 6.

Here, FIG. 5 is a block diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention, and FIG.
In the sectional view taken along the line B-B in the figure, the same reference numerals as those in FIGS. 1 to 3 are the same parts as those in each of the embodiments, so the explanation thereof will be omitted.

The embodiment shown in FIGS. 5 and 6 shows an example in which an air curtain device 15' is installed at the opening serving as the entrance and exit of the conveyance path of the embodiment shown in FIG.

The air curtain device 15' includes a discharge nozzle 16. as shown in detail in FIG. Suction nozzle 17° Motorized fan 18. Heat medium cooler 20. It consists of ducts 21,22.

The air accelerated and pressurized by the motorized fan 18 is
As shown by arrows in the figure, a heat medium cooler 20, a duct 21
The air passes through the discharge nozzle 16, where it is further rectified and accelerated and flows in front of the opening 14 to form an air curtain.

By this air curtain, the saturated steam 12 of the heating medium flowing from the evaporation tank 1 to the opening 14 of the conveyance path (input side conveyance path 2 in the figure) is blocked from leaking into the outside air from the opening 14, and a part of it is blocked from leaking into the outside air. The saturated steam of the air mixes into the circulating air stream of the air curtain.

The air containing the saturated vapor of the heating medium sucked into the suction nozzle 17 passes through the duct 22, is accelerated and pressurized again by the motorized fan 18, is cooled by the heating medium cooler 19, and is then sent to the duct 21. Repeat the cycle below.

When being cooled by the heat medium cooler 20 , the saturated vapor of the heat medium contained in the air is condensed and liquefied and accumulated in the heat medium reservoir 23 . The amount of the liquefied heat medium accumulated in the heat medium reservoir 2:3 is appropriately monitored, and when it has accumulated to a certain extent, it is recovered to the heat medium storage part of the steam generation tank 1a via a return pipe (not shown).

Although the air curtain device at the opening 14 of the carry-in conveyance path 2 has been described in FIG. 6, the same applies to the opening of the carry-out conveyance path 3 side.

According to the embodiments shown in FIGS. 5 and 6, the same effects as those explained in the embodiments shown in FIGS. Since the air curtain device 15' is provided, there is almost no leakage of the heat medium into the atmosphere from the opening of the conveyance path, and it is possible to reduce running costs and improve safety.

In each of the above-mentioned embodiments, the case where the heat medium for generating the liquid curtain is the same type as the heat medium 11 used for soldering in the steam tank 1 has been described, but 1, there is a case where the heat medium for both is different. An example of this will be described with reference to FIG.

FIG. 7 is a configuration diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention, and in the figure,
Components with the same reference numerals as those in FIG. 3 are equivalent to those in the embodiment shown in FIG. 3, so their explanation will be omitted.

In FIG. 7, 44 is a separation device for separating a heat medium for generating a liquid curtain from a heat medium for heating solder, and 45 is a separating device for recovering the separated heat medium for heating solder to the steam generation tank 1a. This is the return piping.

The saturated steam 12 of the heat medium 11 used in the steam tank 1 is very expensive and has a high specific gravity relative to air. Therefore, the embodiment shown in FIG. 7 uses a heat medium for generating a liquid curtain that is cheaper than a heat medium for heating solder and has a different specific gravity to reduce running costs.

A liquid curtain is formed in the transport path 3 on the transport side to cool the soldering member 13, and the heat medium 4 accumulated in the liquid reservoir 26 on the transport side
6 contains liquefied saturated steam 12 as a heat medium for solder heating. This heat medium 46 is delivered to the upper liquid nozzle 30.
The liquid is sent to the lower liquid nozzle 31, but in the separation bag Wt44, the heat medium for generating a liquid curtain and the heat medium for solder heating are separated by using the difference in specific gravity of the heat medium, and the heat medium for solder heating is returned. Steam generation tank 1a via piping 45
Return to the heat medium storage section.

According to the embodiment shown in FIG. 7, the same effects as those described in the embodiments shown in FIGS. Since it is possible to use something cheaper than the medium, running costs can be reduced.

Also, as a heat medium for generating liquid curtain,
If a heat medium for solder heating is selected, the liquid heat medium attached to the soldering member 13 can be melted and removed, and the soldering member will not be carried out with the heat medium liquid still attached. Heating medium for solder heating, which is expensive
1 can be prevented from being consumed, and running costs can be reduced.

It goes without saying that in each of the embodiments other than that shown in FIG. 7, a separation device may be provided to use a different heat medium for generating a liquid curtain and a heat medium for heating the solder.

Furthermore, in each of the above-described embodiments, an example was described in which the liquid mist generating means provided on each transport path for m people is an upper liquid nozzle and a lower liquid nozzle to form a liquid curtain. The present invention is not limited to this, and the same effect can be achieved by generating a mist of the heat medium using a jet nozzle.

〔Effect of the invention〕

As described above, according to the present invention, the object to be processed can be efficiently cooled after soldering, and the amount of heat of the heat medium whose temperature has increased when used to cool the soldered part is used to preheat the object. It is possible to provide a vapor reflow soldering device that recovers heat and reduces leakage of saturated steam as a heat medium, has low running costs, and is highly reliable.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a vapor reflow soldering apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. 3 is a diagram showing another embodiment of the present invention. FIGS. 4 and 5 are block diagrams of a vapor reflow soldering apparatus according to an embodiment, and FIG. 6 is a block diagram of a vapor reflow soldering apparatus according to still another embodiment of the present invention. 5 is a sectional view taken along the line B-B in FIG. 5, FIG. 7 is a configuration diagram of a vapor reflow soldering apparatus according to another embodiment of the present invention, and FIG. 8 is a conventional vapor reflow soldering apparatus. FIG. DESCRIPTION OF SYMBOLS 1... Steam tank, 1a... Steam generation tank, 2... Carrying-in side conveyance path, 3... Carrying-out side conveying path, 4... Conveyor,
DESCRIPTION OF SYMBOLS 11... Heat medium, 12... Saturated steam, 13... Soldering member, 14... Opening part, 15.1'5'...
・Air curtain equipment! . 19...Heat exchanger, 20...Heat medium cooler, 24°30.34.39...Upper liquid nozzle, 25,31. .

Claims (1)

[Claims] 1. A steam tank in which soldering is performed by bringing the saturated steam of a heating medium into contact with the workpiece to heat and melt the solder on the workpiece, and carrying the workpiece into and out of this steam tank. In a vapor reflow soldering apparatus, a means for generating a liquid mist of a low-temperature heat medium for cooling the soldered workpiece is provided in the discharge side transportway, and A vapor reflow soldering apparatus characterized in that the high-temperature heat medium heated to a high temperature as the object is cooled is recovered as a means for preheating the object to be processed in the carry-in conveyance path. 2. In the product described in claim 1, an air curtain device is provided at the opening that becomes the entrance of the carry-in side conveyance path as a means for preheating the processed material in the carry-in side conveyance path, and the air curtain device circulates. A vapor reflow soldering device characterized in that a heat medium circulation path is provided so as to exchange heat between an air flow and a high temperature heat medium generated by the generation of liquid mist of the heat medium in a delivery-side conveyance path. 3. In the item described in claim 1, as means for preheating the workpiece in the carry-in side conveyance path, a liquid mist generating means of a high temperature liquid medium is provided in the carry-in side conveyance path, and the workpiece is preheated. A vapor reflow soldering device that is provided with a heat medium circulation path so that the cooled low-temperature heat medium flows back to the low-temperature heat medium liquid mist generating means in the delivery-side conveyance path. 4. The device according to claim 3, in which a plurality of stages are provided for the low-temperature heat medium liquid mist generation means in the carry-out side conveyance path and the high-temperature heat medium liquid mist generation means in the carry-in side conveyance path. Vapor reflow soldering equipment. 5. A vapor reflow soldering apparatus according to claim 3, which is equipped with an air curtain device equipped with a heat medium recovery means at the opening serving as the entrance and exit of the conveyance path. 6. In the claims 1 to 5, the heating medium liquid mist generating means includes a spray nozzle that generates a mist or liquid curtain using the same heating medium as the heating medium for solder heating in the steam tank. Vapor reflow soldering equipment. 7. In the claims 1 to 5, the heating medium used in the liquid mist generating means is different from the heating medium for solder heating, and the liquid mist generating means in the delivery-side conveyance path is different from the heating medium for solder heating. A heat medium separation device for separating both the heat mediums is provided in the heat medium circulation path connecting the and the liquid mist generation means in the conveyance side conveyance path, and the separated heat medium for solder heating is collected in a steam tank. This is a vapor reflow soldering device.