JPS5947010B2 - Hot air circulation heat treatment furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot air circulation type heat treatment furnace for heat treating an object to be heated by blowing hot air thereon.

As is well known, a hot air circulation heat treatment furnace blows hot air onto the object to be heated in the furnace to heat the object, and the gas inside the furnace whose temperature has dropped by this is sucked in by a circulation fan and the circulation system path. Heat is applied to the gas sucked in by a heat source such as a burner to raise the temperature to a high temperature, and the hot air is then blown onto the object to be heated. Conventional hot air circulation heat treatment furnaces mainly rely on the suction of a circulation fan. It must be of the type with a heat source installed on the side.
In this case, the hot air heated by the heat source passes through the circulation fan, so the heat resistance of the circulation fan becomes an issue, and the need to protect the circulation fan from overheating makes it impossible to heat the hot air above a certain temperature. Ta.

For this reason, the ability to heat the object to be heated is generally low and the object to be heated is heated gradually, so either the transfer speed of the object to be heated is kept low and processing capacity is sacrificed, or equipment costs are reduced. The problem was to increase the length of the furnace and maintain the processing capacity.

In addition, if a heat source is installed on the outlet side of the circulation fan, the hot air heated by the heat source will be blown directly onto the heated object without passing through the circulation fan, making it possible to raise the temperature of the hot air sufficiently. Although the above-mentioned drawbacks can be solved by rapidly heating the material, the lack of agitation of the hot air by the circulation fan results in poor mixing conditions, resulting in the drawback that uneven annealing tends to occur in the object to be heated.

In view of the above, the hot air circulation heat treatment furnace of the present invention compensates for the disadvantages of the drawing formats of providing a heat source on the blowing side of the circulation fan and providing a heat source on the blowing side of the circulation fan, and utilizes only the advantages thereof. , it is possible to provide a heat treatment furnace with a large processing capacity without causing uneven annealing at a low equipment cost.

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a longitudinal sectional view of the entire furnace, Fig. 2 is a sectional view taken along the line X-X, and Fig. 3 is a sectional view taken along the Y-Y line. Let me explain the case.

1 is the object to be heated, 2 is the heating furnace body, 3 is the cooling device,
The object to be heated 1 is carried into the furnace body 2 through the inlet seal roll 4, and is transferred over the furnace rolls 5, 5, etc. while being transferred over the furnace body 2.
The air is heated to 0° C., then cooled by cold air blown from the upper and lower plenum chambers 6, 6' while passing through the cooling device 3, and taken out to the outside via the exit seal roll 7.

For convenience of explanation, the furnace body 2 is arranged in heating zones a and b in the furnace length direction.
If it is divided into soaking zones c and d, the heating element a will have an upper plenum chamber 8a and a lower plenum chamber 9a, the heating zone will have an upper plenum chamber 8b and a lower plenum chamber 9b, and the soaking zone C will have an upper plenum chamber 8a and a lower plenum chamber 9b. An upper plenum chamber 8c, a lower plenum chamber 9c, and an upper plenum chamber 8d and a lower plenum chamber 9d are arranged in the soaking zone d, respectively, and the hot air circulation system path in the heating zone a is connected to a circulation duct 10 as shown in FIG. The hot air circulating system in the soaking zone d is mixed with high temperature hot air blown out from a heat source 12 such as a burner on the blowing side of a circulation fan 11 provided in As shown in FIG. 3, the air is mixed with high-temperature hot air blown from a heat source 15 such as a burner on the blowing side of a circulation fan 14 provided in a circulation duct 13, and is then transferred to an upper plenum chamber 8d and a lower plenum chamber 9d.
Make sure to blow hot air out of your navel.

Although the heating zone is not shown, a heat source is provided on the outlet side of the circulation fan like heating zone a, and the soaking zone C is the same as the soaking zone d.
Similarly, a heat source shall be provided on the oxidation side of the circulation fan.

Note that 16a and 16d are thermocouples 17a to 1 for detecting the temperature of the hot air passing through the circulation fan 11.14, respectively.
7d shows a flue that discharges a part of the gas inside the furnace to the outside without circulating it.

Since the present invention is configured as described above, in the heating zone a, the furnace gas at 800°C is sucked in by the circulation fan 11, and on the outlet side of the circulation fan 11, it is heated to 870°C by the heat source 12. The hot air is blown onto the heated object 1 from the chamber 8a and the lower plenum chamber 9a, and the heated object 1 is rapidly heated.
The furnace gas whose temperature has been lowered to 00° C. is sucked in again by the circulation fan 11.

In addition, the heating element is heated by a circulation fan (not shown).
The furnace gas at 00°C is sucked in, heated to 840°C by a heat source (not shown) on the blowout side of the circulation fan, and the hot air is blown onto the heated object from the upper plenum chamber 8b and the lower plenum chamber 9b. The object to be heated 1 is heated, and the furnace gas, which has been lowered to 800° C. by the heating, is re-inhaled by the circulation fan.

On the other hand, in the soaking zone C, the furnace gas at 777°C is sucked in by a circulation fan (not shown), and on the suction side of the circulation fan, the furnace is heated to 800°C by a heat source (not shown). The hot air is blown from the lower plenum chamber 9c to heat the object 1 to be heated, and the furnace gas whose temperature has been lowered to 77° C. due to the heating is re-inhaled by the circulation fan.

In the soaking zone d, the furnace gas at 788°C is sucked in by the circulation fan 14, and the heat source 1 is placed on the suction side of the circulation fan 14.
5 to 800°C and blow the hot air from the upper plenum chamber 8d and lower plenum chamber 9d to heat the object to be heated 1, and the furnace gas, which has been lowered to 88°C by the heating, is passed through a circulation fan. 14 to re-inhale.

Therefore, the object to be heated 1 is rapidly heated in the heating zones a and b, and is gradually heated and soaked in the soaking zones c and d, thereby making the temperature distribution uniform.

Figure 4 shows the heated object 1 in each zone of a) b j Cj d
This shows the heating state of.

The temperature rise in the soaking zones c and d is very slow compared to the temperature rise in the heating zones a and b.

As explained in the embodiments above, the hot air circulation heat treatment furnace of the present invention rapidly heats the heating zone by blowing high-temperature hot air without passing high temperature above a certain temperature through the circulation fan, and in the soaking zone Since hot air whose temperature has been equalized by stirring by a circulation fan is blown, heat treatment with a large throughput can be provided without causing problems such as uneven annealing.

In addition, in the above embodiment, it was explained that the soaking zone C is provided with a heat source on the suction side of the circulation fan, but in order to increase the heating capacity in the soaking zone C, a heat source is provided on the blowing side of the circulation fan to adjust the temperature of the hot air. It is also possible to raise the temperature and protect the circulation fan from the hot air.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the entire furnace showing an embodiment of the hot air circulation type heat treatment furnace according to the present invention, FIG. 2 is a cross-sectional view taken along the line X--X of FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along the line Y-Y, and is a diagram showing the heating state of the object to be heated. 1... Heat target, 2... Furnace body, 8a t 8b t
8c r8d... Upper Blenheim chamber, 9a, 9b
, 9c. 9d...Lower plenum chamber, 10.13...Circulation duct, 11.14...Circulation fan, 12.15.
...heat source, a, b... heating zone, c, d... soaking zone.

Claims (1)

[Claims] 1 A continuous type furnace that continuously transfers the object to be heated through a heating element to a soaking zone, in which a heat source is provided on the outlet side of a circulation fan in a hot air circulation system path, and in the soaking zone, hot air is A hot air circulation heat treatment furnace characterized in that a heat source is provided on the blowing side of a circulation fan in a circulation system path.