JPH052726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a coil heating/cooling device most suitable for a batch type stationary furnace type heat treatment furnace, particularly an annealing furnace.

(Prior Art) Conventionally, as shown in FIGS. 6 and 7, the annealing furnace as described above has been constructed by opening the charging door 2 of the furnace body 1 and using a cart loaded with a plurality of coils 3, . . . , 3. (not shown) is moved into the furnace, the coil 3 is transferred onto the coil mounting stands 4,..., 4 at the bottom of the furnace, the cart is moved outside the furnace, the charging door 2 is closed, and the inside of the furnace is replaced with a reducing agent. After maintaining the atmosphere, a plurality of radiant tubes (heating/cooling tubes) 5, ..., 5 are placed approximately horizontally in the upper part of the furnace.
At the same time, the gas in the furnace is circulated by a fan 6 and heated by a radiant tube 5, and is blown onto the coil 3 from above to raise the temperature of the coil 3 to about the _A1 transformation point. After this heating process, a cooling process is performed. Then, the radiant tube 5 is cooled, and at the same time, the gas in the furnace is circulated by the fan 6, cooled by the cooler 7 and the radiant tube 5, and is blown onto the coil 3 from above to cool the coil 3 to the temperature at which it can be extracted. (Refer to Japanese Patent Publication No. 52-20925).

By the way, in the annealing furnace as described above, the radiant tube 5 is disposed only above the coil 3, so the coil 3 is heated and cooled mainly from the upper surface side.

Therefore, since the lower surface side of the coil 3 is difficult to be heated and cooled, there are problems in that the temperature difference within the coil 3 becomes large, heating and cooling times are long, and energy loss is also large.

Furthermore, since the number of radiant tubes 5 is limited, there are problems in that too much load is applied, shortening the life of the tubes and the burner, and the temperature difference between the furnace coils 3, . . . , 3 is also large.

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and aims to heat and cool the coil uniformly and in a short time, and to extend the life of the tube, etc. .

(Structure of the Invention) For this reason, the present invention provides a coil stand in the hearth portion for vertically placing the coil so that the end faces of the coil are perpendicular to the hearth, and radiant tubes are arranged opposite to both end faces of the coil. It was constructed as follows.

(Effects of the Invention) According to the present invention, since the radiant tube is arranged facing both end faces of the vertically placed coil, heating and cooling are performed from both end faces of the coil at the same time, so the coil is heated uniformly. In addition to being cooled, the heating and cooling times are also shortened, making it possible to save energy.

Furthermore, since the number of radiant tubes can be increased, the amount of heat burnt by each burner can be reduced, the life of the tubes and burners can be improved, and the temperature difference between the coils of the furnace can also be reduced.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1, 2, and 3, the annealing furnace 10 includes a closed furnace body 11, a charging door 12 is provided on the front wall 11a of the furnace body 11, and a charging door 12 is provided on the front wall 11a of the furnace body 11. Pole-shaped coil mounting stands 14, . . . , 14 on which a total of nine coils 13, .

A coil (tight coil) 1 is placed vertically on a coil stand 14 in the furnace upper part 11d in the furnace main body 11.
A plurality of radiant tubes 20, .

Note that the radiant tube 20 is located at the bottom of the furnace 11.
It may be configured such that it rises from b or protrude from the rear wall 11c.

Each of the radiant tubes 20, . . . , 20 is provided with a burner 21, .

A circulation fan 15 is provided at the lower part of the rear wall 11c of the furnace main body 11, and at the upper part of the rear wall 11c,
A cooler 17 driven by a drive device 16 is provided so as to be retracted outside the furnace during the heating process and protrude into the furnace during the cooling process.

The coil 13 may have a structure in which a ring 25 is passed through the inside of the coil 13, and the coil 13 is supported on a stand 26 and placed vertically. Particularly for heavy coils, it is preferable to provide reinforcement within the ring 25.

Alternatively, as shown in FIG. 4B, a ring 25 may be passed inside the coil 13, a core rod 27 may be passed through the ring 25, and the core rod 27 may be supported by a stand 28 and placed vertically.

In either vertical placement method, annealing is possible without adversely affecting the coil 13.

With the above configuration, the charging door 12 of the furnace body 11 is opened, the trolley loaded with coils 13 is run into the furnace, the coils 13 are vertically stacked on the coil placement stand 14, and the trolley is moved out of the furnace. The charging door 12 is closed to maintain a reducing atmosphere inside the furnace.

Then, the radiant tube 20 is heated by the burner 21 while the cooler 17 is retracted outside the furnace, and at the same time, the circulation fan 15 is driven.

Then, the coils 13 stacked vertically on the coil placement table 14 have radiant tubes 20 on both end surfaces.
At the same time, the gas in the furnace is blown upward by the fan 15, heated by the radiant tube 20, and blown onto both end surfaces and the circumferential surface of the coil 13.
The air is sucked into the air by the fan 15 and circulated.

On the other hand, after the heating process, in the cooling process, air is passed through the radiant tube 20 to cool it, and at the same time, the cooler 17 is thrust into the furnace and the fan 15 is driven.

Then, both end faces of the coil 13 are cooled by the radiant heat of the radiant tube 20, while the furnace gas is blown upward by the fan 15, cooled by the cooler 17, and blown onto both end faces of the coil 13. It is sucked by the fan 15 from between the placement tables 14 and circulated.

In this way, with the radiant tube 20,
Both end faces of the vertically placed coil 13 are heated simultaneously.
Since the coil is cooled, compared to the temperature increase change of the upper end surface a' and the lower end surface b' of the coil according to the conventional method, which is shown by the chain line in FIG. The change is faster and the temperature difference is smaller.

Therefore, according to the proposed method, compared to the conventional method, the temperature difference during heating is halved and the heating time is shortened by about 8 hours, which significantly improves quality and productivity, and reduces the temperature by about 19%. It has also become possible to save energy.

Furthermore, since the number of radiant tubes 20 and burners 21 can be increased from, for example, 24 to 36, the combustion amount of each burner 21 can be lowered or increased, and the life of the tubes 20 and burners 21 can be increased to 3 years compared to the conventional method. What used to be 10 years ago has now been extended to 5 years. Furthermore, by increasing the number of radiant tubes 20 and the like, the temperature difference between the coils 13 of the furnace has also been reduced, and quality and productivity have also improved from this point of view.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an annealing furnace according to the present invention, FIG. 2 is a front sectional view of FIG. 1, FIG. 3 is a plan sectional view of FIG. 1, and FIGS. 4a and 4b are coils. 5 is a graph showing the coil temperature raising effect, FIG. 6 is a side sectional view of a conventional annealing furnace, and FIG. 7 is a front sectional view of FIG. 6. 10... Annealing furnace, 11... Furnace body, 13... Coil, 14... Coil mounting stand, 20... Radiant tube, 21... Burner.

Claims (1)

[Claims] 1. A coil stand is provided in the hearth part for vertically placing the coil so that the end faces of the coil are perpendicular to the hearth, and radiant tubes are arranged facing both end faces of the coil. Coil heating and cooling equipment for heat treatment furnaces.