JPH05296663A - Heating device - Google Patents

Abstract

PURPOSE:To restrict thermal loss in a heating furnace, enable heat gas to be precisely heated in a stepwise manner in a desired temperature range, enable an easy and uniform heating to be attained for both front and rear surfaces of a heated item having a certain thickness and a large size in a thickness direction and to restrict occurrence of poor product caused by a thermal shock. CONSTITUTION:A heating device 1 is comprised of a first preheating chamber 2a, a second preheating chamber 2b, a main heating chamber 3 and a cooling chamber 4. These chambers 2a, 2b and 3 have a blower 5 for feeding out heat gas acting as thermal medium, heaters 12 to 14, flow regulating plates 15 to 17 having a heating means 18a buried at their circumferential walls, inner flow passages 20 to 23 having the heating means 18a buried at their circumferential walls, outer flow passages 27 to 29 having a heating means 19a buried at their circumferential walls and flow regulating plates 24 and 25 having many air cutting plates 23 with shovel-like discharging ports therein and having the heating means 18a buried therein which are independently installed. Thus, the thermal loss can be reduced and a high precision heat treatment can be carried out at the stepwise temperature region. The heating device has a forced discharging blower 30 arranged to prevent the heat gas from being discharged out of the heating device 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the temperature of an object to be heated under the same temperature condition when the object to be heated such as an electronic component mounting substrate coated with solder and industrial processed parts is heated while being conveyed. The present invention relates to a heating device that can obtain a uniform distribution and can perform efficient heat treatment.

[0002]

2. Description of the Related Art Conventionally, when electronic parts are soldered to a circuit board, or industrial processed parts having internal distortion due to processing are heated and heat-treated, and coated parts are dried / baked. , A method of contacting a hot plate as a heating means to locally raise the temperature by heat conduction, a method of immersing in a molten solder liquid, or a method of passing an object to be heated in a metal vapor atmosphere, A method is known in which hot gas, which is a heating medium, is brought into contact like a jet stream.
Such an industrial heating furnace comprises a heating means for heating the object to be heated and a conveying means for adjusting the heating time of the object to be heated, which constitutes the heating means. In addition, a preheating unit usually consisting of one or a plurality of tanks, a main heating unit for maintaining a high temperature at a required heat treatment temperature, and a cooling unit in the last step are provided therein. The main heating unit also includes one or a plurality of baths, and the object to be heated is passed through the baths having a relative temperature difference, and the temperature is changed stepwise to perform heat treatment according to a required temperature profile.

For example, FIG. 9 is a side sectional view of a conventional heating device, showing an example using a heating means system having a propeller fan. As shown in FIG. 9, this heating device is
a propeller fan 5 for sending out air, which is composed of a preheating part a, 2b, a main heating part 3 and a cooling part 4
Generates forced flow in hot air. Reference numeral 9a denotes a rod-shaped heater which is arranged above the object 6 to be heated, and 9b denotes a plane heater which is arranged below the conveyor 7. Reference numeral 10 is a side plate for diverting the hot gas, 1a is an outlet for discharging the hot gas, and 1b is a suction port located on the left and right with respect to the transport direction for discharging the hot gas.

In the heating device having the above-mentioned structure, the article 6 to be heated is placed on the conveyor 7 and the objects 2a, 2b,
It is heated through the tanks 3 and 4. At this time, the hot gas is shunted to the left and right from the outlets 1a arranged at two places on the lower side of the conveyor 7 with respect to the conveying direction, passes through the back side of the side plate 10 to rise, and flows out from the inlet 1b. The fan 5 once forcibly acts as a downward flow, is rectified through the rectifying plate 11, contacts the rod-shaped heater 9a to be heated, and contacts the object 6 to be heated to transfer heat. However, according to this method, the flow of the hot gas that has been once rectified is disturbed while passing between the rod-shaped heaters 9a and contacts the object 6 to be heated as it is, so that a completely uniform heating is not obtained. It was difficult.

As another method, when the temperature of the object to be heated is raised, a hot gas is forced to flow downward from above the conveyor belt by a propeller fan or the like, and a cylindrical pipe is arranged above the object to be heated. Then, there is known a method in which hot air is forcedly flowed in a pipe by a blower, and the heated object is brought into contact with the object to be heated by a jet of hot air through a plurality of small holes formed in the pipe to uniformly heat the object.

[0006]

The above-mentioned prior art has the following problems.

(1) A hot gas as a heating medium is forcibly flowed by a gas delivery means to flow as a downward flow to uniformly heat the whole object to be heated, but a part having a support at the lower part. As it becomes a part with a crowded structure like, etc., only by the flow of hot gas from above,
The heat medium does not go around the side and bottom of the component, and heat transfer becomes insufficient at that portion, resulting in a low temperature. Therefore, the heat treatment is insufficient and the number of defective products is increasing.

(2) The hot gas forms a circulating flow in one direction due to the forced flow, but since the furnace container is large, the flow interference occurs between the tanks, and there is a stagnant portion of the flow. ,
It is difficult to obtain a uniform circulating flow. Since the flow rate of the hot gas on the surface of the object to be heated fluctuates in this way, it is difficult to uniformly heat the object to be heated.

(3) When heat-treating a large object having one side of 60 cm or more, when the heating means is installed immediately above or in the vicinity of the object to be heated, the temperature variation of the heating means is located below the surface of the object to be heated. It was difficult to apply uniform heating because it had a direct effect on the temperature distribution.

(4) When the hot gas comes into contact with the object to be heated at an angle close to vertical from above due to forced flow, the flow stagnates near the contact point and is difficult to be exhausted. Therefore, gas containing impurities evaporated by the reaction is generated. , It flows in a swirling manner in each tank and stays there, making it difficult to collect impurities and increasing the frequency of cleaning and maintenance inside the furnace.

(5) Due to the reason (4) above, if there is a portion where the flow is stopped on the surface of the object to be heated, the flow is not uniform, so that a uniform temperature distribution is obtained on the surface of the object to be heated. Absent.

(6) When heating the object to be heated conveyed by the conveying means in the up-down direction and on both sides, it is necessary to perform heat treatment only on one side and then on the other side. When processing a material that lacks heat resistance or a material that undergoes severe thermal degradation, the object to be heated undergoes a large thermal change more than once, resulting in thermal damage to the object to be heated and functional deterioration, resulting in high productivity. Cause a drop in.

The present invention has been made in order to solve the above-mentioned conventional problems. When the object to be heated is heated by the heating gas as a whole, uniform and uniform heating is possible and radiant heat is applied. An object of the present invention is to provide a heating device capable of efficient heating when used together.

[0014]

[Means for Solving the Problems] In order to solve the above problems,
The present invention includes a plurality of containers filled with gases having different temperatures, and in each container, a hot gas such as an inert gas, a reducing gas, heated air, or a heated metal vapor gas is delivered to heat an object to be heated. It is characterized in that heating means for heating and heating rectifying means capable of adjusting the temperature of the hot gas to a uniform temperature and bringing the heated gas into contact with an object to be heated while maintaining a uniform flow of a constant wind speed are provided.

The heating rectifying means is composed of a flow path made of a heat-resistant material having good thermal conductivity on the inner wall and a flow path made of a heat insulating material for holding a heat insulating effect on the outer wall, and the heating means is provided on the upstream side of the flow. The hot gas is heated on the upstream side, then rectified by a rectifying plate in which a heating means is embedded so as to have a constant wind speed and delivered, and attached to the rectifying plate near the object to be heated. The air flow direction of the hot gas is changed by the wind plate, and the hot gas comes into contact with the object to be heated.

When the hot gas is blown from the most downstream side of the flow path to the object to be heated, the hot gas is swirled from the central direction of the object to be heated to the outer peripheral direction due to the inclination of the wind plate attached to the rectifying plate. Is blown out to draw. The arrangement angle of the wind-blading plate is variable, and the configuration is such that the direction of the hot gas flow to be blown out and the blowout flow rate can be adjusted.

Since the current plate disposed on the most downstream side of the flow path is made of a heat-resistant material having good thermal conductivity and the heating means is embedded, it is possible to directly heat the object to be heated by heat radiation. It was decided.

In order to supplement the heating from the lower surface of the object to be heated, the heating rectifying means in which the heating means is embedded is preferably arranged in at least two directions of the preheating chamber and the main heating chamber.

Before and after the hot gas comes into contact with the object to be heated in one tank of a plurality of containers filled with gases having different temperatures in order to recover impurities generated by heating the object to be heated (upstream, downstream On the side), it is advisable to provide a delivery device independently.

[0020]

The hot gas such as the inert gas, the reducing gas, the heated air and the heated metal vapor gas is first sent to the object to be heated by the gas sending means arranged in the flow path in which the heating means is embedded, The temperature is raised by the heating means arranged downstream of the delivery means. The heated hot gas is forced to flow toward the object to be heated while receiving a heat retaining action in the flow path in which the heating means is embedded. At that time, while the hot gas is passing through the flow path, the turbulent gas flow that has been facing various directions becomes a uniform flow in one direction by passing through the straightening plate in the middle.
Further, while maintaining a constant temperature evenly by the heat convection from the heated flow path, it contacts the object to be heated through the most downstream rectifying plate.

When the hot gas is blown toward the object to be heated, the hot gas is swirled from the center direction of the object to be heated to the outer peripheral direction by the inclination of the wind plate having the non-rotatable scoop-shaped discharge port. Sent to. Since the arrangement angle of the wind plate is variable, the vortex flow of the hot gas blown out can be freely adjusted in the forward and reverse rotation directions from the center, and at the same time, the angle of the wind plate is changed and the cross-sectional area of the blowout port is made smaller to blow out. It is possible to reduce the hot gas flow rate.

As described above, the flow paths for rectifying and sending out the hot gas are provided in two or more directions of up, down, left and right of the conveying means, and the object to be heated is heated from two or more directions, so that the front and back sides in the thickness direction are Even a large-sized object having a large thickness, which is likely to have a temperature difference, can be uniformly heated from the entire surface, and the temperature difference can be reduced in the thickness direction. Further, by providing a cooling means in the flow path located in at least one direction, for example, even for a thin plate-shaped object to be heated that is easily heated from the front surface and is easily damaged by heat, a gas for cooling from the back surface is used. As a result, it is possible to prevent heating of the parts arranged on the surface of the object to be heated and avoid thermal damage.

Further, the method of delivering hot gas in the flow passages arranged in two or more directions in the upper, lower, left and right directions in the vicinity of the carrying means is such that from one direction, the hot gas is blown toward the object to be heated, and at least the remaining one direction. Then, reversely, the suction direction. Regarding the flow rate ratio in the blowing direction and the suction direction at that time, by increasing the suction flow rate, the residual gas containing impurities generated from the object to be heated can be effectively collected, and the impurities stay in the furnace and adhere. There is no.

Further, in order to effectively collect the residual gas containing impurities, two gas delivery means are independently arranged before and after contacting the object to be heated in one flow passage which is the heating and rectifying means,
Regarding the ratio of the flow rate of blow-out and the flow rate of suction, by increasing the suction flow rate after the contact of the object to be heated, the residual gas can be recovered well, and the deposits on the conveying means and the furnace can be reduced.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a side cross-section of a heating apparatus 1 according to the present invention. The furnace body container includes a first preheating chamber 2a and a second preheating chamber 2
b, a main heating chamber 3 and a cooling chamber 4. In the first preheating chamber 2a, the second preheating outlet 2b and the main heating chamber 3,
A blower (propeller) 5 for delivering a heat gas that serves as a heat medium such as an inert gas, a reducing gas, heated air, and a heated metal vapor gas, a motor 36 for driving the blower, heaters 12 to 14, heating means 18a. Rectifier plate 1 with embedded
5 to 17, the inner flow path 2 in which the heating means 18a is embedded in the peripheral wall 2
0 to 22, the outer flow path 2 in which the heating means 19a is embedded in the peripheral wall
7 to 29, baffle plates 24 to 26, in which a large number of wind plate 23 having scoop-shaped discharge ports are arranged and the heating means 18a is embedded, are provided. Further, a forced exhaust air blower 30 is provided so that the hot gas does not go out of the heating device 1. Cooling chamber 4
Is connected to the cooling gas supply system 34, and the intake blower 3
5 are provided. First preheating chamber 2a, second preheating chamber 2
b, the main heating chamber 3 and the cooling chamber 4 communicate with each other near the endless conveyor 7. The conveyor 7 is driven by the conveyor drive device 8 via the drive sprocket 31. Reference numeral 32 is a tension adjusting roller, and 33 is a driven roller.

The operation of the heating device 1 configured as described above will be described below with reference to FIGS. 1 and 2. Figure 1
The article 6 to be heated is placed on the endless conveyor 7 at regular intervals, and is gradually heated to the set temperature while passing through the first preheating chamber 2a, the second preheating chamber 2b, and the main heating chamber 3. , Receives the desired heat treatment while moving on the conveyor 7. That is,
The object 6 to be heated, which was at room temperature, enters the first preheating chamber 2a and is heated, and the temperature is, for example, 150 ° C. near the outlet of the second preheating chamber 2b.
It becomes thermally saturated, the surface temperature becomes constant, and finally, in the main heating chamber 3 for a fixed time, the maximum temperature range is 250 ° C.
The temperature is raised close to the temperature, and then the cooling chamber 4 is entered and the temperature is cooled to near room temperature.

The conveyor 7 is stretched over both ends of the heating device 1 and is moved at a constant speed in the direction of arrow A via a driving sprocket 31 which is interlocked with the conveyor driving device 8. The tension adjusting roller 32 applies a constant tension to the conveyor 7 to prevent the deflection. Normal conveyor 7
Can be varied within a range of 0.1 to 2.0 m / sec. For example, the object 6 to be heated is treated in the first preheating chamber 2a and the second preheating chamber 2b for a long time, and then in the main heating chamber 3. When it is desired to process the cooling chamber 4 quickly and slowly, the transfer means 7a is independently provided in the preheating region (first preheating chamber 2a, second preheating chamber 2b), main heating chamber 3 and cooling chamber 4 (not shown). It is clear that the heat treatment time may be freely set by changing the carrying speed in each chamber by changing the above.

In the cooling chamber 4, a cooling gas such as an inert gas is supplied in order to suppress the oxidation of the object to be heated.
4, and is circulated in the cooling chamber 4 by the intake blower 35. Here, it is apparent that the cooling gas supply system 34 can be released to the atmosphere and simply take in the air outside the heating device 1 to achieve simple cooling.

The heating heater 14 of the main heating chamber 3 has a larger heat capacity than the heating heaters 12 and 13 in the preheating region. Similarly, the blower 5 in the main heating chamber 3 has another heat blower 5 in the preheating region. It is designed to have a larger boosting capacity and a larger air flow rate. Further, the drive motor 36 for blowing hot gas has a heat insulating structure and is arranged outside (upper side) the ceiling walls of the outer flow paths 27 to 29 to suppress direct transfer of heat from the high temperature hot gas.

In FIG. 2, the preheating chambers 2a and 2b and the main heating chamber 3 are shown.
Since both are structurally the same, only the first preheating chamber 2a will be taken up, and an operation of heating the object 6 to be heated by using hot gas as a heat medium will be described.

FIG. 2 is a schematic vertical sectional view of the first preheating chamber 2a. In the first preheating chamber 2a, the enclosed hot gas such as inert gas, reducing gas, heated air, and heated metal vapor gas uniformly heats the object 6 to be heated.
Is forcibly circulated in a certain direction by the above, and is delivered toward the object to be heated 6. At that time, the gas to be delivered is the blower 5
For example, if a multi-blade fan is adopted,
By increasing the pressure by 2 to 883 Pa, the wind speed blown to the object 6 to be heated becomes appropriate, and effective heating is performed. The pressure-increased gas is heated to a predetermined temperature by the heater 12 on the way, and the inner flow path 2 is rectified to rectify it to a constant wind velocity.
It is installed on the downstream side of the heater 12 at a distance of about 0.2 times the inlet diameter of 0, and is further heat-exchanged and rectified by the rectifying plate 15 in which the heating means 18a is embedded. In this way, the hot gas whose temperature and wind velocity are adjusted to be constant in the delivery direction by the straightening plate 15 further contacts the wind plate 24, and the heating means 18a keeps the temperature constant, while discharging the scoop-like gas. It is blown out from the wind plate 23 having an outlet so as to draw a swirling flow on the surface of the object 6 to be heated. After contacting the object 6 to be heated, the hot gas flows from the center direction of the object to be heated toward the outer peripheral direction, and the heating means 19a is provided on the peripheral wall.
The outer flow path 27 in which the
It is restrained by i and guided into the outer flow path 27 by negative pressure. The hot gas does not decrease in temperature even in the flow path 27 on the way, and the circulation of the blower 5 is repeated while increasing the temperature of the gas. The outside of the outer flow path 27 is covered with a container 37 made of a heat insulating structural material to suppress heat loss inside.

FIG. 3 shows a schematic perspective view of the first preheating chamber 2a. For example, when the inner flow passage 20 is of a cylindrical type as shown in the drawing,
The number of stagnant places of the flow of hot gas is smaller than that in the case where the inner flow path 20 is formed in a rectangular prism shape, and the maintenance is easy. The heater 12 can have a large heat transfer area by mounting a fin-tube type heater so as to fill the inner flow path 20 with a large cross-sectional area, and efficient heat exchange is possible. The rectifying plate 15 is made of a thin plate cylinder (concentric circle structure) made of a material having good heat conductivity, and has the sheet resistance heating element 1 inside.
8a is buried and has a sandwich structure to heat and rectify the flow of hot gas. In addition, as a guide for determining the height of the straightening vane 15, it is desirable that the inlet diameter of the inner flow passage 20 be 0.5 times or more. The temperature of the inner flow passage 20 and the outer flow passage 27 can be set independently of each other by heating means, and the inner flow rate 20
Between the outer flow rate 27 and the outer flow rate 27, for example, a heat insulating layer 37a for blocking heat with air is provided.

In FIG. 4, a baffle plate 24 in which a large number of wind cutting plates 23 each having a scoop-shaped discharge port are arranged and a heating means 18a is embedded.
2 shows a plane cross-section from above. The straightening vane 24 is arranged approximately 70 to 200 mm directly above the object to be heated 6, and the straightening vane 15
Is made of a material having good thermal conductivity such as a heat-resistant aluminum alloy, and has a sandwich structure in which a sheet resistance heating element 18a is embedded in an aluminum alloy made of a thin plate. On the lower surface (on the side of the object 6 to be heated), a wind-blading plate 23 having a scoop-shaped discharge port made of a good heat conductive material is arranged in a spiral shape, and hot gas is blown out so as to draw a swirling flow,
There are no hot gas stagnation points and effective heating is possible. Further, since the heating means 18a is provided, the hot gas can be accurately adjusted to the desired heat treatment temperature,
By keeping the rectifying plate 24 warm, it is possible to reduce heat loss from hot gas.

FIG. 5 shows a schematic view from the lower surface of the straightening vane 24, arrow A shows the direction in which hot gas is blown out, and a windbreak plate 23 having a scoop-shaped discharge port shows its blowing direction as shown by arrow B. By making it variable, the swirl flow is generated by blowing in the radial direction from the center to the outer peripheral portion, or by fixing the blowout opening in the circumferential direction (direction parallel to the outer periphery), and further in parallel with the conveying direction of the conveyor 7. It is possible to freely adjust the flow such as a normal flow, a flow perpendicular to the conveying direction, and switching between forward and reverse rotation of the swirling flow. Wind plate 2
In No. 3, the blowout flow rate can be adjusted by further adjusting the blowout angle and increasing or decreasing the blowout cross-sectional area. By adopting a detachable cassette system, the windbreak plate 23 can be easily maintained. Wind plate 23
Can be combined so that a desired flow of hot gas can be obtained by freely arranging so that the cross-sectional area of the blowout port is increased on the center side and decreased on the outer peripheral portion.

A second embodiment according to the present invention will be described with reference to FIG. FIG. 6 shows a side cross-section of the heating device 1. In the figure, 2aa is a first preheating chamber, 2ba is a second preheating chamber, 3a is a main heating chamber, 4a is a cooling chamber, 7 is a conveying means, 12a, 13a,
Reference numeral 14a is a heater, 15a, 16a and 17a are rectifying plates in which the heating means 18a is embedded, 20a, 21a and 22a are inner flow paths in which the heating means 18a is embedded in the peripheral wall, and 24a and 2a.
5a and 26a are provided with a large number of wind plate 23 and are provided with heating means 18
a is a rectifying plate, 27a, 28a, 29a are outer peripheral flow paths in which the heating means 19a is embedded in the peripheral wall, 30 is a forced exhaust blower, 34 is a cooling gas supply system, 35 is an intake blower 35,
Reference numeral 36a is a motor for driving the blower 5a, and 37a is an outer wall having a heat insulating structure, which has the same configuration as that in FIG.

For example, in at least the upper, lower, left, and right directions of the conveyor 7, on the lower surface side of the conveyor 7, as in the upper part, the first preheating chamber 2ab, the second preheating chamber 2bb, and the main heating chamber 3b.
And a means for delivering hot gas and heating means.

Even in the lower part of the conveyor 7, by independently providing the heating / sending means 2c, 3c, 4c for the hot gas, the object 6 to be heated is heated from the lower part so that the temperature distribution in the thickness direction becomes constant and the efficiency is improved. Various heating is possible. Further, since the heating / delivering means 2c, 3c, 4c are independently provided, the temperature of the hot gas can be set, so that precise heat treatment can be performed with high precision. At this time, the hot gas circulation flow rates in the heating / delivery means 2c, 3c, 4c below the conveyor 7 are such that the first preheating chamber 2aa and the second preheating chamber 2b are located above.
a, more than the hot gas circulation flow rate in the main heating chamber 3a,
It is desirable to take about 1.4 to 2.5 times. By increasing the downward flow rate, the residual gas containing impurities generated during heating of the object to be heated 6 can be effectively excluded, and the constant temperature region on both the upper and lower surfaces can be expanded, and uniform heating can be facilitated. Become.

FIG. 7 shows a third embodiment according to the present invention.
FIG. 7 shows a side cross-section of the heating device 1, and the forced exhaust blower 30 in the second embodiment of FIG.
The cooling gas supply system 34 is provided in two directions in the upper and lower directions, and one system is provided for the flow paths 20a, 21a, 22a in the lower part in addition to the cooling chamber 4.

In FIG. 7, a butterfly valve 38 is provided to adjust the flow rate of gas flowing into the cooling gas supply system 34b in the lower part. In the case of the third embodiment,
A cooling gas supply system 34b is provided in order to enhance the cooling action of the object to be heated 6 from below, and the forced exhaust blower 30b is used to adjust the gas flow rate in the furnace to effectively remove residual gas containing impurities. Therefore, it is possible to prevent the heated object 6 from being overheated due to the high temperature gas spraying.
Further, instead of the cooling gas by the cooling gas supply system 34b, it is possible to supply the room temperature atmosphere to give the cooling effect.
it is obvious.

A fourth embodiment according to the present invention is shown in FIG.
FIG. 8 shows a side cross-section of the heating device 1, and the forced exhaust blower 30a in the third embodiment of FIG. 7 is independently provided for each of the first preheating chamber 2a, the second preheating outlet 3a, and the main heating chamber 4a. It has a different structure because it is provided.

In the heating device 1 shown in FIG. 8, the first preheating chamber 2aa, the second preheating chamber 2ba, and the main heating chamber 3a have the same structure. Therefore, the operation is limited to the first preheating chamber 2aa. explain. In the first preheating chamber 2aa, the hot gas is blown out by the blower 5a, flows along the inside flow path 20a, and is heated to a predetermined temperature by the heater 12a. The heated hot gas passes through the straightening vanes 15a and 24a to have a constant wind speed and a constant hot gas temperature, and then contacts the object 6 to be heated for heat transfer. After that, most of the hot gas is recirculated in the outer flow path 27a and used for heating the object 6 to be heated. Here, the forced exhaust blower 30c is connected to the first preheating chamber 2aa.
Since it is provided in the, hot gas is effectively exhausted,
Residual gas containing impurities etc. is forcedly exhausted. In addition, the suction by the forced exhaust blower 30c and the heated object 6
The flow rate with the blower 5a for spraying on the air can be adjusted independently, and the flow of hot gas can be finely controlled.

For example, by increasing the ratio of the flow rate of air blown by the blower 5a on the upstream side and the flow rate of suction by the forced exhaust blower 30c on the downstream side in the flow path 20a on the suction flow rate side on the downstream side, the object to be heated 6 is heated. It is possible to increase the wind velocity of the hot gas and expand the constant wind velocity region, the object 6 to be heated can be easily heated by uniform heating, and the residual gas containing impurities and the like can be effectively exhausted. The ratio of the flow rate blown by the blower 5a on the upstream side to the suction flow rate by the forced exhaust blower 30c on the downstream side is 1: 1.2.
Approximately 1: 1.6 is desirable.

Incidentally, in FIG. 8 showing the fourth embodiment,
The first preheating chamber 2ab, the second preheating chamber 3b below the conveyor 7 with respect to the circulating hot air flow rate of the hot gas in the first preheating chamber 2aa, the second preheating chamber 2ba, and the main heating chamber 3a above the furnace body.
b, the circulating hot air flow rate in the main heating chamber 3b is 1.4 to 2.
The circulation flow rate in the upper part is increased to 5 times, and the ratio of the blowout flow rate by the blowers 9a, 10a, 11a in each chamber in the upper part of the furnace body to the suction flow rate by the forced exhaust blowers 30c, 30d, 30e is 1: 1. .2 to 1: 1.6 may be set so that the suction flow rate is increased.

Further, in FIG. 6 showing the second embodiment,
An inner flow path 20a for heating, rectifying and delivering the gas,
21a, 22a, straightening vanes 24a, 25a, 26a, outer flow paths 27a, 28a, 29a
The sending means is not limited to the vicinity of the conveying means and to the two directions of the upper and lower sides, but by providing the heating means in two or more places of the upper, lower, left and right sides, uniform heating of the object to be heated from two or more directions of the upper, lower, left and right. Not to mention possible.

[0046]

As described above, the present invention realizes the following excellent effects.

(1) A preheating chamber for preheating an object to be heated and a main heating chamber for performing heat treatment in a high temperature region are independently arranged in the heating device, and a conveying means for conveying the object to be heated, By providing a convection heating means in the flow path in which the heating means is embedded in the peripheral wall, there is provided a delivery means for delivering an inert gas, a reducing gas, heated air, a heated metal vapor gas, etc. By effectively adjusting the rectification and temperature distribution to a constant level and imparting a radiant heating effect, it is possible to accurately perform heat treatment in a wide range of sizes from small precision parts to large plate-shaped objects to be heated at two or more stages.

(2) A heat-convection heating effect and radiation are provided by providing a straightening plate having a rotatable scoop-shaped discharge port on a straightening plate made of a heat-resistant material having good thermal conductivity and having a heating means embedded therein, near immediately above the object to be heated. It also has a heating effect, the temperature of the hot gas flow on the surface of the object to be heated can be kept constant at a constant speed, heat loss is small, and efficient heating is possible.

(3) The wind direction of the hot gas blown toward the object to be heated from the wind plate having the scoop-shaped discharge port is such that a vortex is drawn from the central direction of the heated part to the outer peripheral direction. Since the discharge direction of the discharge port from the plate is rotatable, it is possible to switch forward and reverse of the hot gas flow on the surface of the object to be heated, freely adjust the flow direction, and make the angle of the wind plate variable. By doing so, it is possible to adjust the flow rate of blowout, and it is possible to perform efficient heating by finely controlling the flow of blown hot gas.

(4) By arranging the flow paths for rectifying and delivering the hot gas independently of the preheating chamber and the main heating chamber in two or more directions above and below and to the left and right of the conveying means, two objects to be heated can be provided. It is possible to uniformly heat from a direction or more, and even thick ones can be uniformly heated in the front and back and in the thickness direction, and the occurrence of defects due to thermal shock can be prevented.

(5) The heating in the flow path for heating and rectifying the hot gas arranged below the conveying means is stopped and the gas at room temperature is circulated so that the thin plate-like object to be heated can be heated. The cooling action of the cooling gas from below can prevent the heated object from overheating. Furthermore, by providing a cooling gas supply system from the outside to improve the cooling effect from below the heated object, the heat treatment of the surface with high temperature gas can be performed while preventing defects due to overheating of the thin plate-shaped heated object. It is possible.

(6) The preheating chamber and the main heating chamber are independently provided with a delivery means for blowing hot gas toward the object to be heated from the upstream side, contacting the object to be heated, and then sucking in the downstream side, The ratio of the upstream flow rate in the flow path in which the heating means is buried and the downstream flow rate after contacting the object to be heated is increased by increasing the downstream flow rate to effectively remove residual gas containing impurities. The air can be evacuated, and heating from the surface of the object to be heated can be performed accurately and uniformly in each room.

(7) When the flow passages for heating / rectifying and sending out the hot gas are provided side by side in the upper, lower, left, and right directions of the conveying means, the flow rate of the hot gas in the flow passage in one direction and the remaining flow direction The ratio of the flow rate of air blown out in the flow path is such that the residual gas containing impurities generated from the object to be heated can be effectively exhausted by increasing the flow rate of flow out in the flow path in the remaining direction of the transfer means, and the hot gas blown out from one direction can be kept constant. The temperature and constant flow velocity region can be expanded, and uniform heating of at least the upper and lower surfaces of the object to be heated can be facilitated.

(8) The transfer means is independently provided in the three chambers of the preheating chamber, the main heating chamber, and the cooling chamber, and the transfer speed in each chamber is independently controlled, without making the transfer means long and long.
Not only can the required heat treatment time be freely set, the heating device can be made small to be economical, and the object to be heated can be efficiently heated.

[Brief description of drawings]

FIG. 1 is a side sectional view of a heating device according to a first embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view for explaining an operation in the first preheating chamber in the first embodiment of the present invention.

FIG. 3 is a schematic perspective view for explaining the operation of the first preheating chamber in the first embodiment of the present invention.

FIG. 4 is a transverse cross-sectional view from the top of a straightening vane in which a large number of wind-blading plates having scoop-shaped discharge ports are arranged and heating means is embedded.

FIG. 5 is a schematic view from the bottom surface of the current plate in FIG.

FIG. 6 is a side sectional view of a heating device according to a second embodiment of the present invention.

FIG. 7 is a side sectional view of a heating device according to a third embodiment of the present invention.

FIG. 8 is a side sectional view of a heating device according to a fourth embodiment of the present invention.

FIG. 9 is a side sectional view of a conventional heating device.

[Explanation of symbols]

 1 heating device 2a first preheating chamber 2b second preheating chamber 3 main heating chamber 4 cooling chamber 5 blower 6 object to be heated 7 endless conveyor 8 conveyor drive device 12,13,14 heating heater 15,16,17 heating means embedded Rectifier plate 18,19 Electric circuit of heating means 20,21,22 Inner flow path with heating means embedded 23 Scoop-shaped discharge plate 24,25,26 Lower rectification plate with heating means embedded 27,28,29 Outside flow passage with embedded heating means 30 Forced exhaust blower 31 Drive sprocket 32 Tension adjusting roller 33 Driven roller 34 Cooling gas supply system 35 Intake blower 36 Drive motor 37 Flow path consisting of heat insulating structure 38 Butterfly valve

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Claims (9)

[Claims] 1. A furnace for heating an object to be heated, comprising a conveying means for conveying the object to be heated and a gas delivery means for delivering hot gas, and heating means by thermal convection of the delivered gas,
In a heating device provided with a heating means having both a rectifying function of the delivered gas and a radiant heating function, the furnace body is constituted by a plurality of hot gases having different temperatures filled, and the hot gas is provided in each container. It is possible to raise the temperature of the object to be heated to at least two required temperature regions by providing an independent flow path for rectifying and sending out the heat and embedding a heat retaining heating means in the peripheral wall of the flow path. The heating device characterized in that 2. The heating device according to claim 1, wherein the heating means by thermal convection of the delivery gas is provided in a flow path having a heater embedded in a peripheral wall. 3. The heating device according to claim 1, wherein the outer side of the flow path for rectifying and delivering the gas is covered with a material having a heat insulating effect. 4. The heated object as claimed in claim 1, 2 or 3, wherein the flow regulating plate of the flow path is provided with a winder plate having a scoop-shaped discharge port to convey the hot gas blown toward the object to be heated. The air is blown out so as to draw a vortex from the center of the object to the outer circumference, and the arrangement angle of the windbreak plate can be changed. A heating device that can be adjusted. 5. The flow passage for rectifying and sending out hot gas according to claim 1, 2, 3 or 4, in the vicinity of the conveying means, 2
By arranging it in more than one place, at least one of the flow passages uses the delivery gas as a heating means, the other one of the flow passages stops heating, and the gas at room temperature is circulated so that it can be heated from below. A heating device for preventing overheating of the object to be heated by the cooling action of the gas. 6. The heating device according to claim 5, wherein cooling means is provided instead of the heating means in the other one of the flow paths. 7. The heating device according to claim 5, wherein the ratio of the flow rate of the gas blown out from one of the flow paths to the flow rate of the gas discharged from the other flow path is such that the flow rate of the blowout gas on the downstream side is increased. 8. The method according to claim 1, 2, 3, 4, 5, 6 or 7.
In the above, a delivery means for delivering hot gas is provided on the upstream side of the point of blowing contact with the object to be heated, and a delivery means for sucking the hot gas is provided independently on the downstream side of the point of contact with the object to be heated. A heating device in which the ratio of the upstream flow rate in the flow path and the downstream suction flow rate after contacting the object to be heated is set so that the downstream suction flow rate is increased. 9. The heat treatment time according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein each container is provided with a transfer means independently and the transfer speed in each container is independently controlled. A heating device that can be set freely.