JPS6018728B2 - Non-oxidizing atmosphere annealing furnace - Google Patents

Description

[Detailed description of the invention] The present invention relates to a non-oxidizing atmosphere cold furnace.

When annealing is performed in a continuous furnace or a batch furnace, an atmospheric gas containing a ratio is often used. Usually, the object to be annealed is charged into the inner cover of the furnace, and then an atmospheric gas containing a ratio is introduced into the inner cover. The inner cover is further heated from the outside with an electric heater or a radiant tube to perform oxidation-free oxidation.

In this case, most of the atmospheric gas leaks into the furnace from the seal part of the inner cover during phosphorus anchoring work, so the atmosphere inside the furnace outside the inner cover has almost the same gas composition as the atmosphere inside the inner cover. This not only poses the risk of explosion, but also causes other problems such as a reduction in the heat insulation of the furnace wall and a complicated furnace structure.

For example, in the conventional batch type phosphor annealing furnace shown in FIG. It is constructed by sealing the inner cover 2, and then covering the outside of the inner cover 2 with a furnace side 5 having an electric heater 4 and forming the side wall and top wall of the furnace. By arranging the object 6 to be annealed in the inner cover 2, then supplying an atmospheric gas containing 2 gas into the air 8 in the inner cover through the specific gas supply pipe 7, and further activating the heater 4. During this dawn, the atmospheric gas is sealed 3
It flows out into the space 9 outside the inner cover through the air, and is then discharged into the atmosphere from the exhaust pipe 10.

For this reason, the compositions of the atmospheric gases in the spaces 8 and 9 become approximately equal, and the insulation properties of the furnace lining, such as fireproof insulation bricks or ceramic fibers, are therefore significantly reduced.

In other words, due to the difference between the thermal conductivity of the four gases and that of air or combustion gas, the thermal properties of the furnace wall are as shown in Table 1. The conductivity is much higher than that in air, 2 to 2.7 times higher.

As a result, the amount of heat dissipated from the furnace body increases, and the amount of heat lost during the coagulating operation increases. In addition, in the conventional continuous type side anchor furnace shown in FIG.
1 into the furnace one after another, and the inner cover 2
When repeating the racing anchor cycle in which gas is supplied into the furnace twice a day and then taken out from the furnace, both spaces 8 and 9 are in a Q gas atmosphere, and the temperature inside the furnace is maintained at 600°C or higher. In order to prevent an explosion caused by gas inside the furnace blowing out of the furnace and coming into contact with air, doors 12, 13 and 14, 15 are placed at the inlet and outlet of the furnace to close the inlet chamber 16 and the outlet, respectively. compartmentalize room 17,
When loading and unloading bags from the trolley, each of these chambers is filled with an inert gas such as N2, and each door is operated in sequence to prevent direct contact between the Buddha and the air outside the furnace.

For this reason, the structure and operation of the furnace are extremely complicated, and inert gas such as N2 gas is required.In addition, it is necessary to reliably eliminate the risk of explosion of low-temperature gas in the cooling zone a. This requires a safety device with high precision and perfect operation.

The present invention advantageously solves these problems.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the figure, 1 is the bottom wall of the furnace, 2 is the inner cover, and 5 is the side of the furnace lined with fireproof and insulating bricks or ceramic fibers.There are doors 12 and 15 at the inlet and outlet ends of the furnace structure, respectively. will be established. In addition, in this example, a plurality of air inlets 16 are provided in the furnace bottom wall 1, and a plurality of exhaust ports 17 are provided in the top wall of the furnace foundation 5, and each air inlet 16 is connected to a delivery device by an air supply pipe 18. Connect to 19. On the other hand, the exhaust port 17 is connected to the chimney 21 through the exhaust pipe 20'. Further, the exhaust pipe 20 and the air supply pipe 18 constitute a heat exchanger 22 to heat the supply air with the heat of the exhaust gas.
In the figure, reference numeral 11 denotes a truck, on which the object 6 to be annealed is transported, and the object 6 is covered with an inner cover 2 and moved inside the furnace. Furthermore, since the seal between the inner force bar 2 and the truck 11 is performed in the same manner as described with reference to FIG. During the anchorage, it flows out of the inner cover like in the conventional device. Furthermore, the reference numeral 23 in the figure is a means placed within the cooling zone a similar to that shown in FIG. FIG. 4 is an explanatory diagram showing an example of a daily gas piping system, in which a daily gas supply pipe 7 is fixed to a trolley 11, this joint pipe 7 is projected into the basement below the furnace wall, and its tip is Attach coupler 24.

In addition, the daily gas main 25 and the gas branch pipe 26 are connected by a flexible tube 27, and the branch pipe 26 is made to be movable forward and backward by a cylinder 28 connected to both ends thereof, and further,
Branch pipes 29 are made to protrude from the branch pipe 26 at positions corresponding to the specific gas supply pipe 7 positioned in the furnace, and the above-mentioned coupler 24 and a coupler 30 that can be retracted from the neck are attached to the tips of these branch pipes. When operating a furnace with such a configuration, first,
The delivery device 19 is operated to feed air into the furnace, and then the temperature inside the furnace is raised to 760 qo or more, and the ignition means 23 of the cooling zone a is turned on. After that, door 12
, 15 are opened, the material to be annealed on the cart 11 is charged into the furnace, and each door 12, 15 is closed. In this state, under the operation of the cylinder 28, the coupler 24 and the coupler 29 are engaged to supply specific gas into the inner cover 2. Here, the specific gas leaking from the inner cover 2 comes into contact with the heated air in the furnace and burns immediately or when the ignition means 23 is activated. This is the specific gas ignition temperature 57
0°C, and the temperature inside the furnace in the heating zone b is 760°C or higher, so here the specific gas burns immediately upon contact with air, and also has a temperature below the ignition temperature of the gas, This is due to the fact that in the cooling zone a, which has a mixture ratio (in air) of 4 to 74% of the explosive range of the 2 gas, the 2 gas is combusted with the intervention of the ignition means.

In the illustrated example, the air supplied into the furnace is heated to 20,000 ℃ or more based on the function of the heat exchanger 22 after the temperature inside the furnace rises to 760 pm or higher. The required heating energy for the furnace can be reduced compared to the case where the gas is directly supplied into the furnace.

Thereafter, Akatsuki anchor materials are sequentially introduced into the furnace in the same manner.

During this charging, the cylinder 28 is actuated each time to intermittently supply hydrogen gas into the inner cover 2 through the coupler 24 which is sequentially engaged with the coupler 30.
After each material to be hammered passes through the heating belt b and the cooling belt a in the furnace, it is taken out of the furnace through the door 15 and the phosphor annealing process is completed.

Through the combustion of these four gases, the space outside the inner cover 1 is filled with N2, the combustion product 0, and if excess air is supplied, the Q, and the exhaust pipe 20 is filled with and is discharged into the atmosphere through the chimney 21.

As a result, space 10 is filled with N2, day 20,02,
Even if the door 12 or 15 is opened to bring the gas inside the furnace into direct contact with the air outside the furnace, there is no risk of combustion or explosion. Therefore, the doors 12 and 15 can be opened at the same time to load and remove the objects to be annealed. They can be carried out simultaneously, making the structure and operation of the furnace extremely simple.

Furthermore, since the amount of heat dissipated from the furnace wall does not increase, the required heat insulation can be obtained without increasing the thickness of the furnace wall, which is advantageous in terms of thermoeconomics and furnace equipment. Furthermore, when the heat is counted at this time, the results are shown in Table 2.

Second table Amount of gas flowing out into the space 10 lo Sway r Supply air amount 262nd supply air preheating temperature 350°C Exhaust gas temperature
loo0℃ exhaust gas amount
Therefore, according to the present invention, by burning 2 gas per day, 175,900 (Kcal/h
The amount of heat in r) contributes to an increase in the furnace temperature, and there is also a large thermoeconomic benefit.

Therefore, according to the present invention, not only can the furnace be operated safely, but also the structure and operation of the furnace can be simplified, and furthermore, the amount of heat dissipated by the furnace can be reduced and the thermal efficiency can be increased.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional batch-type pounding furnace, FIG. 2 is a sectional view showing a conventional continuous-type pounding furnace, FIG. 3 is a partial sectional view showing an embodiment of the present invention, and FIG. 4 is a partial sectional view showing a specific gas piping system. 1... Furnace bottom wall, 2... Inner cover, 5
...Furnace structure, 16...Air inlet, 17...
...Exhaust port, 19... Delivery device. Sickle 1 figure 2 sickle 3 figure 4 figure

Claims (1)

[Claims] 1 In a non-oxidizing atmosphere annealing furnace where an inner cover is placed inside the furnace wall made of heat-insulating and resistant fireworks and a gas containing H_2 is supplied into the inner cover, multiple air inlets are opened in the furnace wall. A non-oxidizing atmosphere annealing furnace characterized in that the air inlet is opened and the air inlet is connected to a delivery device.