JPS60122881A - Atmosphere furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to an atmospheric furnace having an exhaust stack.

In particular, atmospheric furnaces have built-in exhaust pipes to exhaust binder, which is generated more often than the objects to be fired, out of the furnace. This is an atmosphere furnace with a built-in exhaust stack to maintain a uniform atmosphere.

Conventional atmosphere furnaces do not have an exhaust pipe built into the furnace, but have discharge holes drilled in the top of the furnace, the furnace wall, or the bottom of the furnace.

Therefore, as shown in FIGS. 1 to 3, it was not possible to make the atmosphere around the object to be heated in the atmosphere furnace uniform.

In FIG. 1, reference numeral 1 denotes a furnace body, and there is a hearth 2 at the lower part of the furnace body L, and there is a gap between the hearth 2 and the furnace wall 3, and this gap is used as an air intake port 4. , or an inlet 4 is provided in the gap, the inlet 4 is provided in the lower part, and the exhaust port 6 is provided in the canopy 5, and the gas flow is as shown by arrow a. It is something. Further, in FIG. 2, an exhaust port 6 is provided in the upper part of the furnace wall 3, and an inlet port 4 is provided in the lower part of the furnace wall 3, and the gas flows as indicated by the arrows. As shown in FIG. 3, if the intake port 4 is located in the upper part of the furnace wall and the exhaust port 6 is provided in the hearth 2, the gas will flow as shown by arrow C.

In this way, because conventional atmosphere furnaces do not have a built-in exhaust stack, the gas flow has a path from the intake port to the exhaust port.
The atmosphere around the object to be fired is not made uniform, resulting in uneven characteristics of the object to be fired. In order to prevent unevenness in the properties of the fired product, the usable space must be limited. In addition, the temperature inside the furnace was not easily disturbed by the inhaled gas, and the products to be fired were uneven in size, resulting in poor yield.

The present invention was conceived and invented in order to improve these inconveniences and deficiencies.
An intake port (i.e., a gas introduction pipe) is provided at the top of the furnace wall so that the temperature distribution inside the furnace is not affected even if air is taken in from the tail (tail part). It is designed to rotate evenly.

Embodiments of the present invention will be described with reference to the drawings. However, the description will be made using the same reference numerals for the same parts as in the conventional one.

Figure 4 shows 2, 1 is the furnace body, 2 is the hearth, 3 is the furnace wall, and 5 is the canopy, which is the same as the conventional one. In the present invention, an exhaust pipe 7 is provided approximately in the center of the canopy 5, and an intake port (
A gas inlet pipe) 8 is provided. The exhaust pipe 7 is provided with a small hole 9 that serves as an exhaust hole. A plurality of small holes 9 are provided, but the upper part of the exhaust pipe 7 is rough and the number of small holes 9 is small, and the closer you go to the lower part, the denser the holes are, and the number of small holes 9 increases. It has become. Moreover, since the small holes 9 are radially bored, they serve to uniformize the atmosphere inside the furnace.

In addition, the diameter of the small holes 9 is preferably about 3 mm to 10111 degrees, and the number is preferably about 8 to 30, but the size and number of the small holes are not determined approximately. The positional relationship is determined by the capacity in the furnace, the amount of products to be fired, the amount of intake gas, etc.

Further, as shown in FIG. 5, a damper 10 is provided above the exhaust pipe 7, and the displacement amount can be changed by adjusting the damper 41-10.

Furthermore, at the same time as changing the displacement, the pressure inside the furnace is set to glass pressure rather than the pressure of outside air, so that even if a pinhole or the like is formed in the furnace body, outside air can be prevented from entering the furnace.

In this way, it is possible to maintain a stable atmosphere.

The material for the exhaust pipe 7 may be a metal pipe in low-temperature furnaces up to about 120OC, but in high-temperature furnaces it is better to use alumina, silicon carbide, or other ceramic refractories; When using ceramic refractories, the bulk specific gravity of the ceramic refractories is approximately 1.0 to 4.0; Correspondingly, since it has a small heat capacity, it has good thermal efficiency once inside the furnace and does not generate metallic paper or the like.

Further, in the present invention, a gas introduction pipe 8 is provided in the upper part of the furnace wall 3, and the gas introduction pipe 8 is supplied with gas at room temperature, such as air, nitrogen, oxygen, hydrogen, argon, etc. It is something. The gas introduction pipe 8 is closed at its tip and has a small hole 11 bored in its side surface. A gas body is ejected from this small hole 11, and the flow of the ejected gas is as shown by arrow d, and the gas flow path spreads throughout the furnace, uniformly changing the characteristics of the fired product. It has an averaging effect. In addition, the number of gas introduction v8 may be 2 to 8. In addition, this means that the built-in exhaust pipe 7 is provided in the center of the canopy 5 and the gas introduction pipe 8 is provided in the upper part of the furnace wall 3, and the small hole 9 of the exhaust port of the exhaust pipe 7 is provided in the lower part. Therefore, the distal end of the gas introduction pipe 8 is closed and a small hole 11 for gas ejection is provided on the side surface.

In conventional tH air furnaces, the supplied gas makes the temperature inside the furnace nonuniform, resulting in uneven dimensions, uneven appearance, and uneven characteristics of the fired object. There was a restriction that the object to be fired had to be placed in the path of the gas, but in the present invention, the supplied gas is heated on the upper surface before reaching the lower part.
It does not make the temperature distribution in the furnace non-uniform, and the yield of the product is also high.

Note that the atmospheric furnace of the present invention may be lined with ceramic 7-eyeper. In this case, a seal is applied to the joint between the hearth 2 and the furnace wall 3 to prevent outside air from entering. The object to be fired is placed on a 12I/'i hearth plate, and the hearth plate 12 is placed on a hearth plate support cylinder 13 which is provided so as to protrude from the hearth. These hearth plate 12 and hearth plate support cylinder 13 are also made of ceramic.

As explained above, the present invention is an atmosphere furnace with a built-in exhaust stack and a gas introduction pipe, which homogenizes the atmosphere around the object to be heated, and the inhaled gas is transferred inside the furnace. The furnace is designed so that it can rotate uniformly around the objects to be fired placed in the furnace, and a stable atmosphere can be maintained even if a pinhole is formed in the furnace body by installing a dungeon.

Note that the present invention can also be applied to conventional furnaces; an exhaust pipe according to the present invention is installed in a vertical tube furnace, a box furnace, a crucible furnace, a bell-shaped furnace, and a gas inlet pipe is installed in the upper part of the furnace wall. It is sufficient to install at least one.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a conventional furnace with an outlet in the canopy, Figure 2 is an explanatory diagram of a furnace with an outlet above the furnace wall, and Figure 3 is an explanatory diagram of a furnace with an outlet in the hearth. FIG. 4 is an explanatory diagram of the present invention, FIG. 5 is an explanatory diagram of the exhaust stack, and FIG. 6 is an explanatory diagram of the gas introduction pipe. 2... Hearth, 3... Hearth wall, 4... Big difference, 7...
Exhaust pipe, 8... Gas introduction pipe, 9... Small hole, 10...
・Dan t4-111...Small hole. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A plurality of gas introduction pipes are visible in the upper part of the atmosphere furnace, and a plurality of small holes are provided on the sides of the gas introduction pipes, and at least one exhaust pipe is provided in the canopy. An atmospheric furnace characterized in that a plurality of holes for gas suction are bored on the side of the exhaust pipe, and a damper is provided at the top of the exhaust pipe.