JP4537312B2 - Hot air jet type heating device and heating furnace - Google Patents

Description

  The present invention relates to a hot air jet type heating apparatus and a heating furnace for heating an object to be heated with hot air.

  Conventionally, tin-based soft solder alloys mainly containing a tin-lead eutectic alloy and generally containing lead have been used for mounting electronic components on printed wiring boards. The liquidus temperature of a conventional tin-based soft solder alloy containing lead is 183 ° C for tin-lead eutectic solder, and the maximum temperature for reflow soldering is around 230 ° C, which is about 50 ° C higher than the melting point. The working temperature.

  The temperature of the molten solder affects the wetting and spreading of the solder, the bonding to the copper land on the printed wiring board, and the substrate in the reflow furnace due to the significant difference in the heat capacity between the components mounted on the printed wiring board. Since the temperature difference of the upper soldering part is greatly widened, soldering has been performed at an operating temperature higher than the melting point as much as possible within the heat resistance temperature of the parts.

  However, in response to recent global environmental problems, there is an urgent need to eliminate lead contained in harmful solder, that is, to replace it with lead-free solder. In the case of lead-free solder, various alloy compositions have been proposed, but its liquidus temperature (melting point) is about 220 ° C, about 40 ° C higher than that of conventional tin-lead eutectic solder, and lead Since it is not included, the wettability of lead-free solder is poor.

  On the other hand, the maximum working temperature in reflow soldering must be kept below 240 ° C from the viewpoint of heat resistance of the parts. In order to achieve good soldering under such a limited soldering temperature, the temperature variation of the soldered parts between components during reflow in a printed circuit board with electronic components with different heat capacities It is necessary to suppress.

In order to reduce the temperature variation of the electronic component terminal part on the printed wiring board during reflow soldering, the point is how to heat uniformly. The first thing that can be considered for uniform heating is a blower that uniformly blows hot air onto a printed wiring board and electronic components (see, for example, Patent Document 1).
Japanese Patent Application Laid-Open No. 11-204932 (first page, FIG. 1)

  In order to uniformly heat a printed wiring board on which electronic components are mounted, uniform spraying by hot air blowing is an important requirement, but it is not a sufficient condition to achieve the target. This is due to the following reason.

  First, in a reflow furnace, hot air that is sufficiently heated is sprayed evenly toward a printed wiring board on which electronic components are mounted. The jetted hot air exchanges heat with the terminal part of the electronic component or the printed wiring board at a low temperature on the printed wiring board to heat the electronic component and the printed wiring board.

  The problem here is that the heat capacities of the components mounted on the printed wiring board are significantly different. Even if the same amount of heat is supplied, there is a difference in the way the temperature rises. This is a very big problem. To supply a large amount of heat to an electronic component or printed wiring board, supply hot air with a large temperature difference from the temperature of the printed wiring board or the electronic component mounted on it. Is a simple method.

  However, due to differences in the heat capacities of electronic components and printed wiring boards, some parts with small heat capacities, such as mini-mold transistors and small aluminum electrolytic capacitors, can easily rise in temperature, and there are concerns that they may exceed the heat-resistant temperature. . Therefore, it is impossible to make a temperature difference carelessly.

  That is, the problem cannot be solved only by blowing hot air uniformly. What is important here is how to raise the temperature of electronic components and printed wiring boards with hot air of limited temperature, which improves the heat transfer coefficient between hot air and electronic component terminals or printed wiring boards. It is in.

  When heating by blowing hot air, the above-described heat transfer coefficient becomes a problem in addition to the temperature difference from the object to be heated. From the unit, the heat transfer coefficient is interpreted as the amount of energy given by a medium at a certain temperature per unit area. That is, how efficiently hot air at a certain temperature can supply energy to an electronic component or printed wiring board.

  In the reflow furnace, hot air is blown from the top and bottom against the printed wiring board, but the blown hot air exchanges heat when it hits the surface of the printed wiring board, for example, and then heats the printed wiring board. It flows along the printed wiring board as cold hot air. The cooled hot air flowing along the printed wiring board becomes an obstacle to heat exchange when viewed from the hot air jetted from above.

  That is, there is an intermediate temperature range between the temperature of the hot air and the temperature of the printed wiring board or electronic component, and a region that can be called a temperature boundary layer is formed along the surface of the printed wiring board. In order to efficiently supply heat to the printed wiring board, it is necessary to make this temperature boundary layer as thin as possible, and for that purpose, it is necessary to control the flow of hot air.

  The present invention has been made in view of such points, and by controlling the flow of hot air to make the temperature boundary layer as thin as possible and efficiently supplying heat to the object to be heated, the object to be heated is heated. It is an object of the present invention to provide a hot air jet type heating device and a heating furnace that eliminate the temperature variation.

The present invention includes a blower having a suction port on the lower side of the impeller and an air supply chamber in the periphery, an intake chamber disposed on the lower side of the suction port of the blower, and a plurality of disposed disposed around the intake chamber. An air supply passage, a pressurization chamber disposed below the intake chamber and communicated with the air supply chamber of the blower through a plurality of air supply passages, and immediately after being discharged from the air supply chamber of the blower to the pressurization chamber A plurality of protrusion-shaped hot air having a rectifying mechanism that corrects the bias of the hot air pressure and flow rate, and a mounting board portion disposed below the rectifying mechanism, and that blows hot air toward an object to be heated on the mounting board portion There is a hot air injection unit provided with an injection nozzle, and a recovery plate that is arranged closer to the heated object than the mounting substrate and projects a plurality of hot air injection nozzles toward the heated object. Multiple recovery forcibly recovering hot air A recovery unit provided with a portion, a recovery passage for recovering hot air provided between the mounting substrate portion and the recovery plate and communicating with the intake chamber, and a heat exchanger for heating the cooled hot air, The hot air injection nozzle of the unit is a hot air injection type heating device in which the inner hole is gradually narrowed toward the object to be heated.

  The present invention relates to a furnace body, a transport means for transporting an object to be heated in the furnace body, a plurality of the hot-air jet type heating devices arranged in the furnace body along the transport means for heating the object to be heated, and a transport means. And a cooling device for cooling an object to be heated, which is disposed on the unloading side of the object to be heated facing the extended portion of the furnace body.

According to the present invention, hot air is supplied to the pressurization chamber disposed below the blower via the intake chamber via the plurality of supply passages, and discharged from the supply chamber of the blower to the pressurization chamber. Since the straightening of the hot air pressure and flow rate immediately after correction is corrected by the rectifying mechanism, the hot air having the same temperature and speed can be supplied to all the hot air injection nozzles, and the object to be heated can be heated uniformly.

  According to the present invention, by arranging a plurality of closed-loop hot air injection heating devices that can suppress the influence of heat from hot air circulation systems adjacent to each other along the conveying means in the furnace body, and these The hot air jet type heating device forcibly collects hot air whose temperature has been lowered by heating the object to be heated over the entire area from the recovery port secured over a wide range, and does not hinder the flow of hot air for heating the object to be heated. By thinning the temperature boundary layer on the object to be heated and uniformly heating the object to be heated at a highly accurate temperature, an excellent temperature profile with little temperature variation of the object to be heated can be obtained.

  First, the prerequisite technology of the present invention will be described with reference to FIG. 1 and FIG.

  FIG. 1 shows a plurality of jet ports 1 for jetting hot air H to an object to be heated W on which surface-mounting electronic components are mounted on a printed wiring board, and cold hot air that has changed its direction upon hitting the object to be heated W The hot-air injection apparatus provided with the collection means 2 such as a fan for forcibly collecting h is shown.

  Although this hot air injection device is not configured to blow hot air uniformly against the object to be heated W when partially viewed, the temperature of the hot air H injected from each of the outlets 1 The wind speed is uniform, and the hot air H is finally sprayed uniformly on the surface of the object W to be heated moving in the furnace. A plurality of jet outlets 1 having an arbitrary opening area are arranged at an arbitrary pitch in the transport direction and in the furnace width direction perpendicular to the transport direction. It is biased to the object to be heated W immediately below.

  At this time, as shown in FIG. 1, unless there is an obstruction, the hot air H hitting the object to be heated W flows toward the outer periphery around the collision point along the object to be heated W after heat exchange. , The flow along the similar heated object W of the hot air H jetted from the other adjacent nozzle part 1 collides with the heated object W corresponding to the intermediate part between the two nozzle parts 1, 1; The cooled hot air h after the heat exchange changes its flow upward and is forcibly recovered by the suction force of the recovery means 2.

  For this reason, there is little interference between the cooled hot air h flowing along the heated object W after the heat exchange and the heated hot air H flowing from the ejection port 1 toward the heated object W. The cooled hot air h can be efficiently removed without staying on the surface of the article W to be heated.

  As a result, the temperature boundary layer, which is an intermediate temperature layer along the surface of the object to be heated W, can be thinned, and fresh hot air H before the temperature is lowered can be efficiently supplied to the object to be heated W. The heat exchange rate on the surface of the heated object W is high, that is, a high heat transfer coefficient can be obtained, the heated object W can be uniformly heated at a high precision temperature, and the temperature variation of the heated object W is heated. Can be resolved.

  In addition, although the collection | recovery means 2 showed symbolically the fan between the jet nozzle parts 1 and 1, it also includes a hot-air collection | recovery path | route etc., In short, the cold hot air h which finished heat exchange is to be heated W As long as it can be forcibly collected so as not to stay on the surface, the air may be sucked to the side.

  FIG. 2 shows a hot air spraying device that is a more specific example of the hot air spraying device shown in FIG. 1, and a projection that jets hot air H to the object to be heated W on a flat plate portion 23 as a mounting substrate portion. A hot air spray nozzle 24 is provided as a plurality of jet outlets, and a recovery plate 25 is provided in parallel under the flat plate portion 23. The recovery plate 25 contacts the object to be heated W and changes its direction. A plurality of recovery port portions 26 for forcibly recovering the hot air h thus formed are formed between the hot air injection nozzles 24. Between the flat plate portion 23 and the recovery plate 25, a recovery passage 32 for sucking and collecting a relatively low temperature hot air h after heating the object to be heated is formed. The recovery passage 32 is a hot air circulation system such as a blower or a heater. And communicated with the hot air injection nozzle 24.

  In short, a plurality of hot air jet nozzles 24 for jetting hot air H to the object to be heated W, and the cold hot air h that is provided between these hot air jet nozzles 24 and changes the direction of the object to be heated W are forced. This is a hot air jetting device provided with a plurality of recovery ports 26 for recovery.

  Then, the cold hot air h flowing in the reverse direction after colliding with the heated object W is forcibly recovered at the recovery port 26, so that it stays on the heated object W, which may cause a thick temperature boundary layer. A high heat transfer coefficient can be obtained by removing the cooled hot air h from the top of the article to be heated W.

  That is, the hot air injection nozzle 24 is a hot air injection device that protrudes in a protruding shape from the surface on which the recovery port portion 26 is provided, and directs the hot air H for heating by the protruding hot air injection nozzle 24. As a result, the hot air H for heating and the hot air h whose temperature has been forcibly recovered at the recovery port portion 26 can be clearly distinguished, and mutual interference can be effectively prevented.

  Thereby, the hot air h whose temperature has decreased can be efficiently removed from the object to be heated W, the temperature boundary layer along the surface of the object to be heated W can be thinned, and fresh hot air before the temperature decreases Since H can be efficiently supplied to the object to be heated W, the heat exchange rate on the surface of the object to be heated W can be increased, that is, a high heat transfer rate can be obtained, and the object to be heated W can be evenly distributed at a highly accurate temperature. It can be heated, and the temperature variation of the article to be heated W can be eliminated.

  Next, a related technique of the present invention will be described with reference to FIGS.

  FIG. 3 shows a hot air jetting device 11 and hot air for reflow soldering in which an object to be heated W on which a surface mounting electronic component is mounted on a printed wiring board is electrically and mechanically joined by melting and solidifying a solder paste. An injection type heating apparatus 12 is shown.

  In FIG. 3, in the hot air jet type heating device 12, a heat exchanger 14 for heating a relatively low temperature hot air to a high temperature hot air is disposed inside the hot air generator body 13. In the heat exchanger 14, a plurality of heater elements 16 are horizontally disposed in the hot air flow path 15 in the direction of the object to be heated.

  On the downstream side of the heat exchanger 14, a rectifying mechanism 17 for leveling the hot air over the entire hot air flow path 15 is disposed. In this rectifying mechanism 17, for example, a punching plate having a large number of small holes formed at equal intervals is disposed in the hot air flow path 15.

  Further, on the downstream side of the heat exchanger 14 and the rectifying mechanism 17, a hot air injection device 11 that injects hot air to the article to be heated W is provided.

  The hot air injection device 11 includes a hot air injection unit 21 that is integrally attached to the bottom of the hot air generator main body 13, and a recovery unit 22 that is provided along the hot air injection unit 21.

  The hot air injection unit 21 is provided with a plurality of hot air injection nozzles 24 as projecting jet outlets for jetting hot air H to the article to be heated W on a flat plate part 23 as an attachment substrate part.

  That is, the flat plate portion 23 and the hot air injection nozzle 24 of the hot air injection unit 21 are integrally formed by a casting method including a die casting method using aluminum, zinc, magnesium, or the like as a material, or a drawing method.

  By forming the flat plate portion 23 and the hot air injection nozzle 24 of the hot air injection unit 21 by a casting method or a drawing method, a plurality of hot air injection nozzles 24 can be easily formed on the flat plate portion 23, and casting such as an aluminum die casting method can be performed. Since the flat plate portion 23 and the hot air injection nozzle 24 formed by the method have a high thermal conductivity and a large heat mass, it is possible to prevent the deviation of the heating temperature and to suppress the temperature change. Hot air H having a stable temperature is obtained.

  The recovery unit 22 has a plurality of recovery ports for forcibly recovering the hot air h that has changed its direction against the heated object W on the recovery plate 25 provided in parallel to the lower side of the flat plate portion 23 of the hot air jet unit 21 26 is formed between the hot air injection nozzles 24.

  The hole shape of the hot air injection nozzle 24 and the recovery port portion 26 may be a circular shape, an oval shape, or a narrow slit shape that is elongated in a direction perpendicular to the heated object conveyance direction. It is desirable that the hot air injection nozzle 24 has a shape protruding from the recovery port portion 26 for recovering the hot air h whose temperature has been lowered by heating the object to be heated W toward the object to be heated W.

  These recovery ports 26 are holes drilled in the bottom of the recovery plate 25 provided so as to cover the lower portion and the peripheral side portion of the hot air generator body 13, whereas the hot air injection nozzle 24 is a flat plate portion. From 23, the recovery plate 25 is penetrated, and is projected from the surface on which the recovery port portion 26 is provided.

  A temperature sensor 27 such as a thermocouple for adjusting the heater temperature is inserted into at least one of the plurality of hot air injection nozzles 24 so as not to disturb the flow of the hot air H.

  The heated hot air h heated by the heated object jetted from the hot air jet nozzle 24 of the hot air jet device 11 and collected in the collection port 26 is sucked by the suction air mechanism 31 and supplied to the heat exchanger 14.

  In the intake air mechanism 31, a recovery passage 32 is formed between the flat plate portion 23 and the recovery plate 25 of the hot air injection unit 21 to suck and recover a relatively low temperature hot air h after heating the object to be heated. A recovery passage 33 formed between the peripheral side portion of the hot air generator body 13 and the peripheral side portion of the recovery plate 25 is communicated with the passage 32. The recovery passage 33 is partitioned into an upper portion of the hot air generator main body 13. The formed intake chamber 34 is communicated, and a suction port 36 of a blower 35 such as a sirocco fan is opened above the central portion of the intake chamber 34.

  In the blower 35, an impeller 38 provided inside a casing 37 is rotatably supported by a rotating shaft 39, and a motor 41 installed outside the casing 37 is connected to the rotating shaft 39. An air supply chamber 42 provided around the impeller 38 is communicated with the hot air generator body 13 through a plurality of air supply passages 43.

  As shown in FIG. 4, the plurality of hot air injection nozzles 24 and the plurality of recovery ports 26 are arranged in either a grid pattern or a staggered pattern.

  That is, FIG. 4A shows a plurality of hot air injection nozzles 24 arranged in a grid pattern on the entire surface of the flat plate portion 23 of the hot air injection unit 21 and a plurality of recovery port portions between these hot air injection nozzles 24. 26 is similarly arranged in a grid pattern.

  4B, a plurality of hot air injection nozzles 24 are arranged in a staggered manner on the entire surface of the flat plate portion 23 of the hot air injection unit 21, and a plurality of recovery port portions 26 are provided between these hot air injection nozzles 24. Are similarly arranged in a zigzag pattern.

  In this way, by arranging the hot air injection nozzles 24 in a grid pattern or a zigzag pattern over the entire surface of the flat plate portion 23 of the hot air injection unit 21, a plurality of hot air injection nozzles 24 are evenly spaced over the entire surface of the flat plate portion 23. It can arrange | position and can eject the hot air H with respect to the to-be-heated material W equally.

  FIG. 5 shows a heating furnace 51 using the hot-air injection device 11 and the hot-air injection type heating device 12, and a pair of endless transfer chains 53 for transferring an object to be heated W through the inside of the furnace body 52, and these A conveying means 55 for the object to be heated W is provided by a sprocket 54 for rotating the conveying chain 53, and a plurality of hot-air jet type heating devices 12a for preheating are provided in the furnace body 52 along the conveying means 55. , 12b, 12c and a plurality of hot-air jet type heating devices 12 for reflow.

  Next, the effect of the hot air injection device 11 and the hot air injection type heating device 12 shown in FIGS. 3 to 5 will be described. In FIG. 3, solid arrows indicate the flow of high-temperature hot air H heated by the heat exchanger 14, and hollow arrows indicate hot air whose temperature has decreased after the heat exchange with the article W to be heated. h.

  The low temperature hot air discharged from the impeller 38 of the blower 35 to the air supply chamber 42 is supplied into the hot air generator body 13 through the air supply passage 43 and heated by the heater element 16 of the heat exchanger 14 to rise in temperature, The flow rate and pressure of the hot air are made uniform over the entire cross section of the hot air flow path 15 by the rectifying mechanism 17, and hot hot air H at a high temperature is evenly injected from each hot air injection nozzle 24 of the hot air injection device 11 and is transferred by the transfer means 55. A heated object W such as a printed wiring board and a board-mounted electronic component is heated with hot hot air H.

  The hot air H ejected from the hot air jet nozzle 24 toward the object to be heated W collides with the printed wiring board itself or the board-mounted electronic component to exchange heat, and when these board or electronic component is heated, the temperature decreases. The hot air becomes cold and flows along the upper surface of the substrate. However, when it collides with the hot air for heating ejected from the adjacent hot air jet nozzle 24, the flow is changed upward as shown in FIG.

  As shown in FIG. 6B, a part of the upward hot air h after the heat exchange is merged in the form of being wound around the hot air H flowing downward toward the heated object W as shown in FIG. It moves toward the object to be heated W again and reaches the object to be heated W while causing the temperature of the hot air H to decrease. As a result, the heating efficiency is lowered as a whole, but the actual recovery is performed as shown in FIG. Since the unit 22 is provided, when the hot air h cooled after the heat exchange with the article to be heated W flows upward, the cooled hot air h is sucked from the recovery port portion 26 of the recovery unit 22 It is forcibly recovered by the suction force of the mechanism 31.

  Thus, the cooled hot air h does not interfere with the hot air H ejected from the hot air jet nozzle 24, passes through the recovery passages 32 and 33 and the intake chamber 34 from the recovery port portion 26, and from the suction port 36 of the blower 35 to the impeller. Then, the air is sucked into 38 and further discharged from the impeller 38 into the air supply chamber 42.

  As described above, the heat exchanger 14, the rectifying mechanism 17, the hot air injection device 11, and the intake air mechanism 31 can constitute a closed-loop self-supporting hot air circulation device that heats the article W to be heated and The reduced hot air h can be efficiently removed from the object to be heated W by forcibly recovering it from the recovery port portion 26 using the suction force of the intake air mechanism 31. It is possible to suppress the interference between the heated hot air H heated and ejected from the hot air jet nozzle 24 and the hot air h that has been heated to lower the temperature of the article W to be heated, and has a flat, uniform and temporally stable accuracy. Since the heated object W can be uniformly heated by the high temperature hot air H, the temperature variation of the heated object W to be heated can be eliminated.

  Further, the projecting hot air jet nozzle 24 gives a directivity to the hot air H for heating, thereby clearly distinguishing the hot air H for heating and the hot air h whose temperature has been forcibly recovered by the recovery port portion 26 from being lowered. Separately, mutual interference can be effectively prevented.

  Next, the necessity of the recovery unit 22 and the function and effect thereof will be described in detail.

  In order to uniformly heat the printed wiring board itself of the object to be heated W and the electronic components on the substrate, it is not sufficient to uniformly supply the hot air H heated to a constant temperature to the object to be heated W. Interference between the cooled hot air h after heating the electronic component and finishing the heat exchange and the hot air H for heating the substrate or the electronic component cannot be suppressed.

  As a result, the overall heating efficiency is lowered, the entire printed wiring board cannot be uniformly heated, and the desired temperature distribution in the substrate cannot be satisfied.

  In order to solve this, the point is how to quickly remove the hot air h, which has been lowered in temperature by heating the printed wiring board, from the surface of the printed wiring board while suppressing interference with the hot air H for heating. .

  For this purpose, a recovery unit 22 is provided in the middle of each adjacent hot air jet nozzle 24 to quickly remove hot air h that has been heat-exchanged and cooled after it has been exchanged from the substrate.

  The recovery port portion 26 of the recovery unit 22 is desirably provided at an intermediate position between an arbitrary hot air injection nozzle 24 and all the hot air injection nozzles 24 adjacent thereto.

  The hot air H ejected from the hot air jet nozzle 24 toward the printed wiring board collides with the printed wiring board itself or the board-mounted electronic component on the object to be heated W, exchanges heat therewith, and heats the board or the electronic component. To do. On the other hand, after colliding with the object to be heated W, the cooled hot air h flows along the upper surface of the substrate, but when it collides with the hot air H ejected from the adjacent hot air jet nozzle 24, the flow changes upward.

  A part of the hot air h after the heat exchange is moved toward the printed wiring board again while being wound around the high-temperature hot air H flowing in the vicinity toward the substrate, and the temperature of the hot air H is lowered. In this case, the heating efficiency is lowered as a whole. In this case, when the hot air h cooled after the heat exchange flows upward, there is a recovery port portion 26, and this recovery port portion Since the cold hot air h is sucked into 26, the cold hot air h is discharged out of the system from the recovery port part 26 without interfering with the hot air H for heating.

  By doing so, the hot air H ejected from the hot air jet nozzle 24 does not receive much interference from the hot air h that has been cooled after the heat exchange with the printed circuit board and the electronic components on the board. In addition, it is possible to uniformly heat the electronic components on the printed wiring board and the board itself in a stable state for each hot air jet nozzle 24, and to suppress variations in temperature of these electronic parts and the board itself. .

  Then, as shown in FIG. 5, by arranging the hot air injection type heating device 12 having the hot air injection device 11 having the recovery unit 22 in the furnace body 52 along the conveying means 55, the following Thus, the outstanding temperature profile with few temperature dispersion | variation by the temperature measurement location of the to-be-heated material W is obtained.

  In order to compare the heating capability of the printed wiring board according to the related art of the present invention, the hot air injection device 11 provided with the recovery unit 22 as shown in FIG. 6A and the recovery unit 22 as shown in FIG. The hot-air injection apparatus 11a when not providing is shown. FIG. 7 shows an example of temperature profile measurement on the substrate that shows the difference in heating capability between the two.

  In the hot air injection device 11 used in the present embodiment, hot air injection nozzles 24 having a circular injection hole shape and a projection height of 20 mm from the lower surface of the recovery unit 22 are arranged in a staggered manner on the flat plate portion 23 of the hot air injection unit 21. Then, the recovery unit 22 provided with the recovery port portion 26 for recovering the hot air h whose temperature was lowered after heating the heated object was used in the recovery plate 25 at an intermediate position between all the adjacent hot air injection nozzles 24.

  The object to be heated W is only a printed wiring board having a size of 250 mm × 300 mm. In order to simplify the measurement, an electronic component is not mounted, and is fed into the reflow heating furnace 51 by conveyance by the conveyance chain 53. FIG. 6 (A) shows a reflow zone in which only the hot air injection unit 21 is provided after preheating with hot air injection type heating devices 12a, 12b, 12c for preheating, as shown in FIG. 6 (B). In this way, the printed wiring board is heated by the hot air H injected from the hot air injection nozzle 24 in the reflow zone in which the hot air injection unit 21 and the recovery unit 22 are provided, and the K thermocouple attached to the reflow surface of the printed wiring board The temperature of the substrate surface was measured at 45, and the measurement result of the temperature profile shown in FIG. 7 was obtained.

  After the measurement, the temperature gradient during temperature rise (this temperature gradient is referred to as “temperature rise rate”) and the peak temperature were compared from these temperature profiles, and the effectiveness of the technique related to the present invention was evaluated. Here, the distance between the hot air injection nozzle 24 and the printed wiring board was the same.

  Table 1 below shows a comparison result of the temperature rise rate, the maximum temperature reached, and the temperature variation in the substrate shown in the graph of FIG.

  As can be seen from the results shown in Table 1, it can be seen that by providing the recovery port portion 26 between each hot air jet nozzle 24 for heating, the substrate is uniformly heated to a high temperature and a remarkable effect is obtained. .

  This eliminates temperature variations between board-mounted components during reflow, and hot air that can provide good electrical and mechanical bonding even with lead-free solder alloys that have a narrow usable temperature range below the component heat resistance temperature The injection device 11, the hot air injection type heating device 12, and the heating furnace 51 can be provided.

  Although the illustrated hot air injection type heating device 12 is disposed on the upper side of the conveying means 55, the hot air injection type heating device 12 may be disposed on the lower side of the conveying means 55. It may be arranged on both sides of the lower side.

  Furthermore, in the embodiment, the projection height of the hot air injection nozzle 24 as the ejection port portion is set to 20 mm, but this projection height may be set within the range of 0 to 20 mm. When the projection height of the hot air jet nozzle 24 is set to 0 mm, the surface provided with the recovery port portion 26 can be made flat, maintenance such as cleaning of this surface becomes easy, and the object to be heated W There is no possibility of interfering with the hot air injection nozzle 24, and when the hot air injection type heating device 12 is disposed on the lower side of the conveying means 55, it becomes easy to collect the article to be heated W that has fallen off the conveying means 55.

  In this way, hot air h that has been cooled after heat exchange with the object to be heated W is efficiently and forcibly recovered from the recovery port 26 using the suction force of the intake air mechanism 31 from the surface of the object to be heated W, The temperature boundary on the object to be heated W by suppressing the interference between the hot air H for heating heated by the heat exchanger 14 and ejected from the hot air jet nozzle 24 and the hot air h that has been cooled by heating the object W to be heated. The layer can be thinned, and the object to be heated W can be uniformly heated at a high accuracy temperature, and temperature variations of the object to be heated W can be eliminated.

  Next, an embodiment as a premise of the present invention will be described with reference to FIG. 8 or FIG. In addition, the same code | symbol is attached | subjected to the part similar to the related technology shown by FIG. 3 thru | or FIG. 5, and the description may be abbreviate | omitted.

  FIG. 8 shows a reflow soldering hot air jetting device 11 for electrically and mechanically joining a heated object W on which a surface mounting electronic component is mounted on a printed wiring board by melting and solidifying a solder paste. 11u and hot air injection type heating devices 12 and 12u are shown.

  In FIG. 8, hot air injection devices 11 and 11 u disposed above and below the conveyance surface of the object to be heated W send hot air H to the object to be heated W on the flat plate parts 23 and 23 u as the mounting substrate parts. Hot air injection nozzles 24 and 24u are provided as a plurality of protrusion-shaped jet outlets to be jetted.

  The upper and lower hot-air spray nozzles 24 and 24u are arranged so that the other hot-air spray nozzle 24u or 24 is located on the basis of either the upper or lower hot-air spray nozzle 24 or 24u from the surface target position with respect to the conveyance surface of the object W to be heated. In each direction of the object to be heated and in the furnace width direction perpendicular to the conveying direction, the nozzle is disposed at a position shifted by a distance smaller than the nozzle mounting pitch (preferably 1/2 pitch of the nozzle mounting pitch). Has been.

  Here, the flat plate portions 23 and 23u of the hot air injection device 11 and the plurality of hot air injection nozzles 24 and 24u may be integrally formed, but die casting made of aluminum, zinc, magnesium, or the like as a material. It can be integrally formed by a casting method including a method, or an integral forming method such as a drawing method.

  Such integral molding methods such as casting and drawing methods can easily form high-precision nozzle groups necessary for the mechanism to control the flow of hot air to obtain a high heat transfer coefficient. Can do.

  In other words, by forming the flat plate portions 23 and 23u of the hot air injection devices 11 and 11u and the plurality of hot air injection nozzles 24 and 24u by a casting method or a drawing method, the plurality of hot air injection nozzles 24 and 24u are formed into flat plates. Since it can be accurately and easily formed on the portions 23 and 23u, it is easy to control the flow of the cold hot air h flowing through the nozzle gap.

  Furthermore, since the hot air injection nozzles 24, 24u and the flat plate portions 23, 23u integrally formed by a casting method have good thermal conductivity and large heat mass, it is possible to prevent these heating temperature deviations and to suppress temperature fluctuations. Therefore, it is possible to inject the hot air H at a uniform and stable temperature from the hot air injection nozzles 24, 24u. In addition, it is easy to attach the recovery plates 25 and 25u having the plurality of recovery port portions 26 and 26u in terms of structure.

  In the hot air injection device 11 shown in FIG. 8, the recovery plates 25 and 25u having a large number of recovery ports 26 and 26u disposed between the hot air injection nozzles 24 and 24u are provided from the tips of the hot air injection nozzles 24 and 24u. It is provided near the flat plate portions 23 and 23u. The recovery plates 25 and 25u and the flat plate portions 23 and 23u form recovery passages 32 and 32u for the cooled hot air h.

  The hot air spray nozzles 24, 24u are projected from the recovery plates 25, 25u, and this heating is performed by giving direction to the hot air H for heating by the projecting hot air spray nozzles 24, 24u. It is possible to clearly distinguish the hot air H for use and the hot air h having a reduced temperature that is forcibly recovered by the recovery ports 26 and 26u of the recovery plates 25 and 25u, thereby effectively preventing mutual interference.

  As shown in FIG. 8, each of the hot air spray nozzles 24 and 24u of the upper and lower hot air spray devices 11 has a recovery port portion provided in the recovery plate 25u at a lower position facing the upper hot air spray nozzle 24 through the conveying surface. 26u is installed, and the recovery port portion 26 provided in the recovery plate 25 is installed at the upper position facing the lower hot air jet nozzle 24u via the transport surface.

  For this reason, when there is no object to be heated W, the hot air H ejected from the upper hot air jet nozzle 24 is collected in the recovery port portion 26u of the recovery plate 25u facing directly, and the flow is disturbed in the vicinity on the transport surface. In addition, the hot air H ejected from the lower hot air jet nozzle 24u is collected in the recovery port portion 26 of the recovery plate 25 that directly faces, and does not disturb the flow in the vicinity of the conveying surface.

  That is, the hot air H ejected from the hot air jet nozzles 24, 24u on the upper and lower sides of the transport surface is collected in the recovery ports 26u, 26 on the opposite side without interfering with each other, and therefore always on the transport surface. An air curtain function capable of supplying fresh hot air H for heating is obtained, and a temperature drop due to disturbance of the hot air flow on the conveying surface can be prevented.

  Further, after the hot air H ejected from the upper hot air jet nozzle 24 collides with the object to be heated W, the hot air h that has been cooled after finishing the heat exchange is forcibly applied to the recovery port portion 26 provided in the recovery plate 25. The hot air h which is sucked and quickly removed from the surface of the heated object W and the hot air H ejected from the lower hot air jet nozzle 24u collides with the heated object W. It is forcibly sucked into the recovery port portion 26u disposed in 25u and quickly removed from the surface of the article to be heated W.

  The shape of the hot air spray nozzles 24, 24u may be any shape such as a circular shape, an oval shape, or a rectangular slit shape. The shape can be determined by determining the opening area from the wind speed of the hot air H to be ejected and the amount of heat sufficient to heat the article to be heated W.

  When the hot air jet nozzles 24, 24u have an elliptical shape, the nozzle longitudinal direction can be arranged obliquely in the range of 90 to 30 degrees with respect to the heated object conveyance direction. is there.

  In any case, the hot air injection nozzles 24, 24u are projected from the flat plate portions 23, 23u into a nozzle shape. By making the nozzle shape, the hot air H to be ejected is given directivity and the hot air spreads. The influence of the accompanying temperature boundary layer can be kept small, and a higher heat transfer coefficient can be obtained.

  In addition, a temperature sensor 27 for monitoring the hot air temperature is disposed in at least one of the plurality of hot air injection nozzles 24, 24u so as not to obstruct the flow of the hot air as much as possible. Output control of the heater element 16 for heating h is performed.

  Further, in the premise embodiment shown in FIG. 8, the tips of the hot air injection nozzles 24, 24u, which are separate from the recovery plates 25, 25u, protrude toward the conveying surface side. A protruding nozzle tip and a recovery port 26, 26u are integrally formed on 25u, and the nozzle tips of these recovery plates 25, 25u are continuously connected to the nozzle body protruding from the flat plates 23, 23u. As a result, the same structure as that of the hot-air injection devices 11 and 11u shown in FIG. 8 can be obtained.

  The height of the recovery passages 32, 32u for the hot air h formed between the flat plate portions 23, 23u as the mounting substrate portions of the hot air injection nozzles 24, 24u and the recovery plates 25, 25u is at least 5 mm to 50 mm. It is desirable from the viewpoint of maintaining the performance of hot air recovery and ease of manufacturing while maintaining accuracy.

  In the example shown in FIG. 8, the flat plate portions 23 and 23 u have a gradient such that the central portion bulges toward the transport surface side, so that the flat plate portions 23 and 23 u and the recovery plates 25 and 25 u are separated from each other. The recovery passages 32 and 32u for the hot air h formed in the above are those in which the passage gap is gradually enlarged from the location far from the exit of the recovery passages 32 and 32u (that is, the central portion) toward the exit side of the recovery passages 32 and 32u. The passage clearance between the recovery passages 32 and 32u that gradually expands toward the outlet side makes it possible to cope with the hot air recovery flow rate that increases toward the outlet side.

  The hot air h that has been cooled after the heat exchange is sucked into the recovery passageway 33 that is communicated with the recovery port portions 26 and 26u via the recovery passageways 32 and 32u and that is disposed at the four ends of the hot air jet unit 21, The collection passage 33 is on the suction side of the blower 35, and the heat exchanger 14 is disposed in the collection passage 33.

  That is, in FIG. 8, the blower 35 has an impeller 38 provided inside a casing 37 rotatably supported by a rotating shaft 39, and a motor 41 installed outside the casing 37 is connected to the rotating shaft 39. However, the heat exchanger 14 is formed by disposing a plurality of heater elements 16 in a recovery passage 33 connected to the suction side (negative pressure side) of the blower 35.

  The hot air h cooled by heat exchange with the object to be heated W is sucked into the recovery passage 33 from the recovery ports 26 and 26u provided in the recovery plates 25 and 25u through the recovery passages 32 and 32u. After being heated by the heater element 16 of the heat exchanger 14 provided in the recovery passageway 33, it is sucked into the suction port 36 of the blower 35.

  At this time, since the cooled hot air h is heated by the heater element 16 of the heat exchanger 14 located on the suction side of the blower 35, the heated hot air H is sucked into the blower 35 and mixed. For this reason, there is no temperature unevenness in the hot air H discharged from the impeller 38 rotating at high speed of the blower 35 to the air supply chamber 42 provided in the outer peripheral portion, and hot air having a uniform temperature can be supplied.

  The air supply chamber 42 communicates with the pressurization chamber 44 through a plurality of air supply passages 43. The pressurizing chamber 44 is provided with a rectifying mechanism 17. Since this rectifying mechanism 17 is disposed between the blower 35 and each hot air jet nozzle 24, the hot air H immediately after being discharged from the air supply chamber 42 of the blower 35 to the pressurizing chamber 44 has a pressure and a flow rate. Even if there is a bias, they can be corrected by the rectifying mechanism 17 and hot air at the same speed can be ejected from each hot air jet nozzle 24.

  The hot air H rectified by the rectifying mechanism 17 is jetted from the hot air jet nozzles 24, 24u of the hot air jet device 11 toward the heated object W (printed wiring board on which electronic components are mounted) on the transport surface.

  FIG. 9 is a diagram showing a correlation between the arrangement of the hot air jet nozzles 24 and 24u and the recovery port portions 26 and 26u provided in the recovery plates 25 and 25u of the upper and lower hot air jet type heating devices 12. FIG.

  For convenience, the upper hot air jet type heating device 12 provided on the upper side of the transport surface is provided with its respective hot air jet nozzles 24 arranged in a staggered manner, and each of the recovery ports 26 of the recovery plate 25 includes: It is disposed between the hot air jet nozzles 24.

  On the other hand, the hot air injection nozzle 24u of the lower hot air injection type heating device 12u that is symmetric with respect to the conveying surface is disposed at a position corresponding to the recovery port portion 26 of the upper recovery plate 25, and the lower portion The recovery port portion 26u of the recovery plate 25u of the hot air injection type heating device 12u is disposed at a position corresponding to the upper hot air injection nozzle 24.

  Further, as shown in FIGS. 8 and 9, the plurality of recovery port portions 26 and 26u are arranged at locations far from the outlets of the recovery passageways 32 and 32u (that is, the central portions of the recovery plates 25 and 25u). The one arranged on the outlet side of the collection passages 32 and 32u has a smaller opening area. By narrowing the opening area of the collection port portion 26 and 26u on the outlet side of the collection passages 32 and 32u, the hot air suction force is reduced. The flow rate of hot air collected from the outlet side where it is likely to act can be made equal to the flow rate of hot air collected from a place that is not so, and variations in the flow rate of hot air collected from place can be prevented.

  The other parts of the lower hot-air jet type heating device 12u have the same structure as the upper hot-air jet type heating device 12, and the description thereof will be omitted.

  Next, the operation and effect of the premise embodiment shown in FIGS. 8 and 9 will be described.

  In each of the upper and lower hot-air jet type heating devices 12 and 12u, the hot air H heated by the heat exchanger 14 and supplied to the pressurizing chamber 44 by the blower 35 is evenly rectified in the entire pressurizing chamber by the rectifying mechanism 17. Hot air H having an equal temperature and wind speed is supplied to all the hot air injection nozzles 24, 24u.

  When there is no object to be heated W at the tips of the hot air jet nozzles 24, 24u, the hot air H ejected from the upper hot air jet nozzle 24 is collected in the recovery port portion 26u of the lower recovery plate 25u directly facing, The hot air H ejected from the hot air jet nozzle 24u is collected in the recovery port portion 26 of the upper recovery plate 25 facing directly, and the hot air ejected from the upper part and the hot air ejected from the lower part are conveyed between the transport chains of the transport means 55. It will change smoothly through space.

  For this reason, the hot air H ejected from the hot air jet nozzles 24, 24u on the upper and lower sides of the transport surface is collected in the recovery ports 26u, 26 on the opposite side without interfering with each other, and the heated object W is transported. Since the hot air H for heating is always supplied to the surface, the temperature does not decrease due to the disturbance of the hot air flow on the transport surface.

  On the other hand, when the object to be heated W is located at the tip of each hot air jet nozzle 24, 24u, the hot air H ejected from the upper and lower hot air jet nozzles 24, 24u is blown onto the surface of the object to be heated W.

  At that time, these hot air injection nozzles 24, 24u are two-dimensionally distributed in parallel with the object to be heated W, and the object to be heated W is conveyed along the hot air injection nozzles 24, 24u. When the spray nozzles 24 and 24u are partially viewed, the hot air sprayed from the individual hot air spray nozzles 24 and 24u even if the spray nozzles 24 and 24u are not configured to blow the hot air H uniformly against the article W to be heated. Since the temperature and the wind speed of H are uniform, finally, the hot air H is blown uniformly onto the surface of the heated object W to be conveyed.

  Hot air H injected from a plurality of hot air injection nozzles 24, 24u dispersedly arranged in the direction of conveying the object and in the width direction is concentrated on the surface of the object W to be heated located on the extension of the hot air injection nozzles 24, 24u. After the heat exchange, the hot air H that collides with the heated object W flows toward the outer periphery along the surface of the heated object W around the collision point, but from the adjacent hot air injection nozzles 24, 24u. A similar flow along the object to be heated W collides with the object to be heated W corresponding to the intermediate portion of the hot air jet nozzles 24 and 24u, and then from the object to be heated W by the forced recovery action by the recovery ports 26 and 26u. Change the flow in the direction of separation.

  For this reason, there is less interference between the cooled hot air h flowing along the heated object W after the heat exchange and the heated hot air H flowing in toward the heated object W, and the heated object W It is possible to efficiently remove the cold hot air h that flows along the surface of the object W, and to thin the temperature boundary layer along the surface of the article W to be heated.

  Thereby, since the fresh hot air H before temperature fall is efficiently supplied to the to-be-heated object W, the heat exchange rate in the surface of the to-be-heated object W is high, ie, a high heat transfer rate can be obtained.

  The cooled hot air h is recovered by the recovery passages 32 and 32u. The recovery passages 32 and 32u for recovering the hot air are the recovery plates 25 and 25u provided with the recovery ports 26 and 26u and the hot air injection nozzles 24 and 24u. Is provided between the flat plate portions 23 and 23u of the steel plate, a recovery path for the cooled hot air h can be secured over a wide range, and the cold hot air h flowing in the reverse direction after colliding with the object to be heated W is forced over the entire area. It is possible to efficiently remove the cooled hot air h staying on the heated object W from the heated object W, which can cause the formation of a thick temperature boundary layer. Obtainable.

  In this way, the upper and lower hot-air jet type heating devices 12 and 12u include the hot-air jet devices 11 and 11u that supply the hot air H to the article to be heated W, and the recovery ports 26 and 26u of these hot-air jet devices 11 and 11u. The object to be heated W is forcibly sucked in the hot air h after heating the object to be heated and the intake air mechanism 31 for circulating the hot air H heated by the heat exchanger 14 to the hot air injection nozzles 24 and 24u. When there is an upper and lower separation type closed loop hot air circulation device, and when there is no object to be heated W, an upper and lower integrated closed loop hot air circulation device is constituted. When multiple sets of 12 and 12u are installed in the furnace as shown below, the influence from adjacent systems can be suppressed.

  Next, FIG. 10 shows a heating furnace 51 using the hot air injection devices 11 and 11u and the hot air injection heating devices 12 and 12u.

  The heating furnace 51 conveys the article to be heated W by a pair of endless conveyance chains 53 that convey the article to be heated W through the inside of the furnace body 52 and a sprocket 54 that drives the conveyance chains 53 to rotate. A means 55 is disposed, and along the conveying means 55, a plurality of hot air jet type heating devices 12a, 12b, 12c for preheating and a plurality of hot air jet type heating devices for reflow are provided in the upper part of the furnace body 52. 12 and 12 are disposed, and a plurality of hot air injection heating devices 12ua, 12ub, 12uc for preheating and a plurality of hot air injection types for reflow are provided in the lower part of the furnace body 52 along the conveying means 55. Heating devices 12u and 12u are provided.

  Thus, along the conveying means 55 in the furnace body 52, closed loop hot air injection heating devices 12a, 12b, 12c, 12, 12 and 12 that can suppress the thermal influence from the hot air circulation systems adjacent to each other and By arranging a plurality of hot air injection type heating devices 12ua, 12ub, 12uc, 12u, 12u, these hot air injection type heating devices recover the hot air h whose temperature has been lowered by heating the article W to be heated. Forcibly recovered from 26 and 26u and does not interfere with the flow of hot air H for heating the object to be heated, so the temperature boundary layer on the object to be heated W is thinned and the object to be heated W is heated uniformly at a high temperature. By doing so, an excellent temperature profile with little temperature variation of the article to be heated W can be obtained.

  The conveying means 55 is provided to extend to the heated object carrying side of the furnace body 52, and is opposed to the extended part of the conveying means 55 on the heated object carrying side of the furnace body 52 so as to Cooling devices 56 and 56u are arranged.

  The transport chain 53 of the transport means 55 is guided by a guide rail 57 disposed along these hot air jet type heating devices and cooling devices. The guide rail 57 is connected to the hot air jet type heating devices 12a, 12b, 12c, 12, 12 and hot air injection type heating device 12ua, 12ub, 12uc, 12u, 12u, heating unit rail 57a heated by cooling device 56, 56u, cooling unit rail 57b, heating unit rail 57a And a heat insulating part 58 interposed between the cooling part rails 57b.

  As described above, since the heat insulating portion 58 is interposed between the heating portion rail 57a and the cooling portion rail 57b, the hot air injection type heating devices 12a, 12b, 12c, 12, 12 and the hot air are passed through these guide rails 57. Can prevent the jet type heating devices 12ua, 12ub, 12uc, 12u, 12u and the cooling devices 56, 56u from interfering with each other thermally, preventing the possibility of lowering the heating efficiency or lowering the cooling efficiency it can.

  Next, the best embodiment of the hot air spray nozzle and the recovery plate will be described with reference to FIG.

  As shown in FIG. 11, hot air including a plurality of hot air spray nozzles 24 whose inner holes are gradually narrowed toward the object to be heated, and a recovery plate 25 that sucks the cool hot air h from between the hot air spray nozzles 24. In the injection device 11, the recovery plate 25 is formed in a mountain shape so as to bulge toward the recovery passage 32 at each recovery port portion 26 </ b> A, and a suction hole for sucking the cold hot air h after heating the object to be heated at the top As a result, the recovery plate 25 is formed in a concave shape on the side facing the article to be heated W in each recovery port portion 26A.

  And, when recovering the cooled hot air h after heating the object to be heated by the concave recovery port portion 26A, the recovery efficiency is better than the flat recovery port portion 26 provided with the suction hole 28 in the flat plate. Thus, the overall heating capacity can be improved.

  This is because the hot air h that has been cooled after the heated object is smoothly recovered by the concave recovery port portion 26A, so that there is no eddy current that tends to occur on the heated object W side of the recovery plate 25. The temperature boundary layer on the surface of the object W becomes thick, and this temperature boundary layer becomes a barrier, and the heat transfer efficiency of the hot air H injected from the hot air injection nozzle 24 to the heated object W is deteriorated. This is because the temperature boundary layer on the surface of the object to be heated W is thinned by eliminating the eddy current, and the heat transfer efficiency of the hot air H injected from the hot air injection nozzle 24 is improved.

  According to the experiment, the heat transfer coefficient is improved by about 5 to 10% in the case of the concave recovery port portion 26A compared to the case of the flat recovery port portion 26.

  As described above, the hot air injection device 11 in each related technology and embodiment is provided with a plurality of hot air injection nozzles 24 for injecting the hot air H to the object W to be heated, and the hot air injection nozzles 24 provided between these hot air injection nozzles 24. Since there are a plurality of recovery ports 26 for forcibly recovering the hot air h that has changed its direction when it hits the heated object W, the hot air h that has been heated to reduce the temperature thereof is heated by the hot air injection nozzle 24. By the forced recovery from the recovery port portion 26 provided between the hot air H for heating ejected from the hot air injection nozzle 24 and the hot air h having a lowered temperature that is forcibly recovered by the recovery port portion 26 The hot air h whose temperature has been reduced can be efficiently removed from the object to be heated W while suppressing interference, and the temperature boundary layer along the surface of the object to be heated W can be made thin, and fresh before the temperature decreases. Hot air H can be efficiently supplied to the object to be heated W. The heat exchange rate on the surface of the heated object W can be increased, that is, a high heat transfer coefficient can be obtained, the heated object W can be uniformly heated at a high precision temperature, and the temperature variation of the heated heated object W can be reduced. Can be resolved. In particular, since the plurality of recovery ports 26 provided between the plurality of hot air injection nozzles 24 recovers the cooled hot air h after heating in an orderly manner, the flow of hot air before and after heating the article W to be heated is more uniform. It can be formed in such a hot air flow, and interference between the hot air H for heating and the cold hot air h can be eliminated, and a high heat transfer rate can be obtained.

  Note that the hot air injection devices 11 and 11u, the hot air injection type heating devices 12 and 12u, and the heating furnace 51 according to the present invention are also used as a curing furnace used when an electronic component is bonded to a printed wiring board with a thermosetting resin. Applicable.

It is explanatory drawing which shows the flow of the hot air which came out from the separate jet nozzle part of the hot air injection apparatus used as the premise of this invention. It is explanatory drawing which shows the flow of a hot air in the case of collect | recovering the hot air which came out from the jet nozzle part same as the above in the collection port part. It is sectional drawing which shows the related technique of the hot air injection apparatus and hot air injection type heating apparatus concerning this invention. (A) is a bottom view showing one arrangement example of the jet outlet part and the recovery port part of the hot air jet apparatus and the hot air jet type heating apparatus, and (B) is a bottom view showing another arrangement example thereof. It is sectional drawing which shows the related technique of the heating furnace using a hot air injection type heating apparatus same as the above. (A) is sectional drawing of the hot air injection apparatus which provided the collection port part, (B) is sectional drawing of the hot air injection apparatus which does not provide a collection port part. Example of measuring temperature profile on printed circuit board with hot air jetting device provided with recovery port part shown in FIG. 6 (A) and hot air jetting device with no recovery port part shown in FIG. 6 (B) It is a characteristic view which compares and shows. It is sectional drawing which shows embodiment which becomes a premise of the hot air injection type heating apparatus concerning this invention. It is an arrangement | positioning figure which shows the example of arrangement | positioning of the ejection part provided in the upper and lower sides of the to-be-heated material conveyance surface of a hot air injection type heating apparatus same as the above, and a collection | recovery port part. It is sectional drawing of the heating furnace using a hot air injection type heating apparatus same as the above. It is sectional drawing which shows the best embodiment of a hot air injection nozzle and a collection | recovery board of a hot air injection type heating apparatus same as the above.

W Object to be heated
12 Hot air jet type heating device
14 Heat exchanger
17 Rectification mechanism
21 Hot air injection unit
22 Recovery unit
23 Flat plate as mounting board
24 Hot air injection nozzle
25 Collection plate
26, 26A Collection port
27 Temperature sensor
32, 33 Collection passage
34 Air intake chamber
35 Blower
36 Suction port
38 impeller
42 Air supply room
43 Air supply passage
44 Pressurization chamber
52 Furnace
55 Transport means
56 Cooling device

Claims (4)

A blower having a suction port on the lower side of the impeller and having an air supply chamber around the periphery ;
An intake chamber disposed below the intake port of the blower,
A plurality of air supply passages arranged around the intake chamber;
A pressurizing chamber disposed below the intake chamber and communicated with the air supply chamber of the blower via a plurality of air supply passages;
A rectifying mechanism that corrects the bias of hot air pressure and flow rate immediately after being discharged from the air supply chamber of the blower to the pressurization chamber ;
A hot air jet unit having a mounting board portion disposed on the lower side of the rectifying mechanism and provided with a plurality of protruding hot air jet nozzles that jet hot air to the object to be heated on the mounting board portion ;
A recovery plate is disposed on the heated object side from the mounting substrate and has a plurality of hot-air spray nozzles protruding toward the heated object side, and the recovery plate forcibly recovers the hot air that has changed its direction upon contact with the heated object. A recovery unit having a plurality of recovery ports;
A collecting passage for collecting hot air provided between the mounting substrate portion and the collecting plate and communicating with the intake chamber;
A heat exchanger for heating cold hot air,
The hot air injection type heating device, wherein the hot air injection nozzle of the hot air injection unit is gradually narrowed toward the object to be heated. The collection passage communicated with the intake chamber is arranged at the four-way end portion of the hot air injection unit from between the mounting substrate portion and the collection plate,
The hot-air jet type heating device according to claim 1, wherein the heat exchanger is provided in any of the recovery passages arranged at the four ends. The hot air jet type heating device according to claim 1 or 2, further comprising a temperature sensor that is provided in any of the hot air jet nozzles and controls the heat exchanger by monitoring the hot air temperature. A furnace body;
Conveying means for conveying an object to be heated in the furnace;
The hot-air jet type heating device according to any one of claims 1 to 3, wherein a plurality of heaters disposed in the furnace body along the conveying means are heated.
A heating furnace comprising: a cooling device for cooling an object to be heated disposed on an unloading side of the object to be heated facing the extended portion of the conveying means.

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