JPS6219265B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for cooling a workpiece that has been brazed in a heating section of a brazing furnace.

Generally, in the case of a continuous brazing furnace, a workpiece loading section and a workpiece unloading section are provided at the upstream and downstream ends, respectively, and the inside of the furnace is made into a non-oxidizing atmosphere using exothermic conversion furnace gas, etc. A workpiece using copper or a copper alloy as a brazing material is carried into this furnace from the above-mentioned carrying-in section. Then, the carried workpiece is sequentially passed through a preheating section, a heating section, and a cooling section using a conveyor belt to undergo brazing treatment.

Here, in the heating section, the workpiece is heated to over 1000°C in order to melt the brazing material. In order to cool such high-temperature workpieces, conventionally, a water jacket is provided on the inner wall of the cooling section.

However, cooling by the water jacket alone is not sufficient, and therefore the length of the cooling section must be increased in order to lower the workpiece to a predetermined temperature. For this reason, not only does the furnace itself become longer and occupy a larger area in the factory, but the conveyor belt also becomes longer, the load on the motor that moves this conveyor belt increases, and the number of workpieces that stay in the furnace increases. Since the number of processes increases, more time is required for processing, and processing capacity also decreases. On the other hand, if the length of the cooling section was shortened and the residence time of the workpieces in the cooling section was increased instead, the intervals between the workpieces being carried into the furnace would have to be increased, which would result in a large throughput. The width decreases.

For this reason, it is possible to shorten the cooling time by forcibly stirring the atmospheric gas in the cooling section, but in a continuous furnace that has a loading section and an unloading section for the workpieces, This has the disadvantage of drawing in outside air, making the flow of atmospheric gas unstable, leading to oxidation of the workpiece surface, and resulting in poor brazing.

The present inventor has devised the present invention in order to solve the above-mentioned conventional problems, and the purpose thereof is to shorten the length of the cooling section and reduce the area occupied by the furnace as much as possible. It is an object of the present invention to provide a cooling device for a furnace brazing furnace which can perform proper brazing in a shortened processing time and also leads to energy saving.

In order to achieve such an object, the present invention provides a continuous brazing furnace in which a plurality of cooling fans are installed in the cooling section of a continuous brazing furnace, which is provided with a workpiece loading section and a workpiece unloading section at the upstream and downstream ends, respectively. The gist is that the cooling fans are arranged along the cooling section, and the blowing direction of the cooling fans is reversed, for example, alternately or every plurality of cooling fans, so that the atmospheric gas in the cooling section is swirled and circulated.

An example of the implementation of the present invention will be explained in detail below based on the accompanying drawings.

FIG. 1 is a side sectional view of a furnace according to the present invention, and FIG. 2 is a plan view. The tunnel-shaped furnace 1 is arranged from the upstream side to the downstream side, including a front table 2, a preheating section 3, and a heating section 4. , an annealing section 5, a cooling section 6, an annealing section 7, and a rear table 8 are successively provided. In the furnace 1, an endless mesh belt 9 and rollers 10 supporting the same are provided extending from the front table 2 to the rear table 8. I'm trying to move.

On the front table 2, there is a work loading section 1.
2, and a suction duct 13, a shutter 14, and a curtain 15 for shutting off the furnace atmosphere gas from the outside air are provided in succession to the workpiece loading section 12. A preheating section 3 is disposed downstream of the curtain 15, heaters 17 are provided on the peripheral wall of the preheating section 3, and thermocouples 18 for temperature measurement are embedded in the upper wall. Heaters 19 are also provided on the peripheral wall of the heating section 4 following the preheating section 3, and thermocouples 20 for temperature measurement are embedded in the upper wall.

A water jacket 21 for cooling is formed on the circumferential wall of the slow cooling section 5 that follows the heating section 4, and a water jacket 22 is also formed on the circumferential wall of the cooling section 6 that follows this slow cooling section 5. .

Cooling fans 23, 24, 2 are provided on the upper wall of this cooling section 6 at equal intervals along the direction of movement of the workpiece.
5,26 are installed. These cooling fans 23, 24, 25, 26 are rotated by motors 27, 28 fixed to the outer wall of the cooling section 6, as shown in FIG. Rotating in the opposite direction, the fan 24,
26 is adapted to be rotated in the forward direction by a motor 28. Thus, a swirling flow of atmospheric gas as shown by arrow 29 is generated within the cooling section 6, and the atmospheric gas is circulated within the cooling section 6.

Further, downstream of the slow cooling section 7 following the cooling section 6, there is a curtain 30 that blocks the outside air and the furnace atmosphere gas.
Ducts 32 for sucking atmospheric gas etc. leaked from the shutter 31 and the curtain 30 are respectively provided, and furthermore, a workpiece unloading section 33 is formed on the rear table 8.

In addition, the dew point of the metamorphic gas from a non-illustrated metamorphic gas generator disposed near the furnace 1 was passed through a cooling device to lower the dew point, and a portion of the metamorphic gas from the cooling device was heated by the heat of the suction ducts 13 and 32. Thereafter, the pipes 34 and 35 wrapped with heat insulating material are introduced into the heating section 4 through the introduction pipes 36 and 36, and a part of the metamorphosed gas is not heated but is passed through the pipe at a low temperature. 37 into the cooling section 6 from near the axes of the cooling fans 23, 24, 25, and 26 in the cooling section 6.

In the above, the workpiece inputted from the workpiece loading section 12 is brazed while passing through the preheating section 3 and the heating section 4, and the workpiece after this treatment is transferred to the slow cooling section 5.
The mesh belt 9 is carried into the cooling section 6 through the mesh belt 9 . Then, in the cooling section 6, the low-temperature metamorphic gas, that is, the atmospheric gas is circulating while swirling, so that the workpiece is rapidly cooled. At this time, since the atmospheric gas in the cooling section 6 is only circulating, it is not necessary to use other locations such as the slow cooling sections 5 and 7 or the heating section 4.
This does not disturb the atmospheric gas inside the furnace, so that there is no disadvantage of outside air flowing into the furnace.

Note that the above is merely an example of implementation, and although the drawings show an arrangement in which four cooling fans are provided, this number may be arbitrary. There is no need to alternately rotate the cooling fan forward and backward.
For example, it is possible to make groups of two and have each group perform forward and reverse rotations.Furthermore, the rotation direction of all the cooling fans may be the same, and instead of that, the blades of some of the cooling fans may be tilted. The direction may be reversed.

Further, the air blowing capacity of the cooling fan that rotates in the direction of pushing back the atmospheric gas in the cooling unit 6 to the heating unit 4 may be increased. By doing this, the atmospheric gas that has become high in temperature due to the heat of the workpiece in the cooling section is introduced into the heating section 4, thereby increasing the heating efficiency within the heating section 4 and leading to energy savings.

Next, a specific comparative example will be explained based on FIG. 3 to further clarify the effects of the present invention.

Comparative Example When general sheet metal parts are brazed with copper, the temperature curve when heated to around 1150°C in the heating section 4 and then cooled down to around 180°C in the cooling section 6 equipped with only a water jacket is shown in Figure 3A. As shown by the symbol a, the cooling rate is slow, and the speed of the belt conveyor is
When the speed is 500 mm/min, the length of the entire furnace is approximately 30 m as shown in FIG. 3B.

On the other hand, when the cooling section structure of the present invention is adopted, the heating section 4 heats the temperature to around 1150°C.
The cooling rate when cooling to around 180°C in the cooling section 6 is faster than that of the conventional one, as shown by the symbol b in Fig. 3A.
The total length of the furnace will also be shortened to about 20 m, as shown in Figure 3C.

Therefore, the speed of the belt conveyor is 500mm/
If it is min, then by simple calculation, the work time can be reduced by about 20 minutes.

As is clear from the above description, according to the present invention, a plurality of cooling fans are arranged along the conveyance direction of the workpiece in a belt-transfer type continuous brazing furnace, and the rotation direction of these cooling fans is alternately rotated. However, since the direction of inclination of the blades is set in the opposite direction for each alternate cooling fan, the atmospheric gas in the cooling section swirls and high temperature atmospheric gas from the heating section does not flow into the cooling section. do not have. Therefore, a high-temperature workpiece that has been brazed can be cooled down to a predetermined temperature in a short period of time, and since the atmospheric gas in the furnace is not disturbed and outside air is not drawn in, good brazing can be achieved. I can do it. Since the overall length of the furnace can be made as short as possible, the area occupied by the furnace can be reduced, and the wire diameter of the mesh belt can also be reduced, making it lightweight and the belt itself inexpensive. This also reduces the load on the belt drive motor, which helps with power consumption.Furthermore, by varying the air blowing capacity of the fans to send high-temperature atmospheric gas to the heating section, heating efficiency in the heating furnace can be improved. It has great effects, such as being able to increase the

[Brief explanation of the drawing]

The drawings show an example of the implementation of the present invention,
Fig. 1 is a vertical sectional side view of a continuous brazing furnace to which the cooling device according to the present invention is applied, Fig. 2 is a plan view of the same continuous brazing furnace, and Fig. 3A is a graph showing the relationship between the cooling rate of the workpiece and the length of the furnace. FIGS. 3B and 3C are graphs showing the relationship between the lengths of the furnace according to the present invention and the conventional furnace. In addition, in the drawing, 1 is a continuous brazing furnace, 4 is a heating part,
6 is a cooling section, 12 is a workpiece loading section, 23, 2
4, 25, and 26 are cooling fans, and 33 is a workpiece unloading section.

Claims (1)

[Claims] 1. In a tunnel-shaped continuous brazing furnace with a workpiece loading section at the upstream end and a workpiece loading section at the downstream end, cooling is provided downstream of the heating section. A slow cooling section is arranged on the upstream side and a downstream side of the cooling section, and a plurality of cooling fans are disposed on the ceiling of the cooling section along the workpiece conveyance direction. In order to prevent high-temperature gas from being drawn in from the heating section, the plurality of fans are alternately rotated in opposite directions, or the blades are alternately inclined in opposite directions. Cooling device in the furnace. 2. By making the air blowing capacity of one of the alternately arranged cooling fans larger than the air blowing capacity of the remaining cooling fans, a part of the atmospheric gas in the cooling part is pushed back into the heating part to maintain balance. A cooling device for a brazing furnace according to claim 1, characterized in that: 3. The cooling device for a brazing furnace according to claim 1, wherein a water jacket is formed in the cooling section.