JPH086007Y2 - Vacuum furnace - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum furnace used for sintering processing and the like.

[0002]

2. Description of the Related Art As a conventional vacuum furnace used for a sintering process or the like, a single tight box is arranged in the furnace and an in-furnace gas such as an inert gas is introduced to the outside of the tight box. An atmosphere gas such as a reactive gas is introduced into the tight box, and the dirty atmosphere gas after the treatment is subjected to a differential pressure flow from the outside to the inside through the tight box, together with the gas in the furnace. It is common to exhaust directly to the outside. The role of such a tight box is to discharge harmful atmosphere gas and wax and other impurities secondarily generated by processing to the outside of the furnace without contacting the internal components such as the heater, heat insulating material, and furnace wall. The point is that you can do it.

[0003]

By the way, the atmospheric gas must be kept at a predetermined concentration inside the tight box in order to effectively act on the object to be treated. However, in the above-described single tight box structure, when the furnace gas and the atmosphere gas are different types of gas, the atmosphere gas is diluted by the furnace gas flowing into the tight box, and its concentration is inconsistent. There is an inconvenience that it will end up.

The present invention aims to solve such problems.

[0005]

The present invention adopts the following constitution in order to achieve the above object.

Namely, a vacuum furnace according to the present invention, as shown in FIG. 1, the outer is placed doubly in the furnace 1 Taitobo'
Box 2 and inner tight box 3 and outer tight box
Gas introduction path for introducing the in-furnace gas a to the outside of the chamber 2
Atmosphere gas b inside L ₂ and inside tight box 3
Gas introduction line L ₃ for introduction and outer tight box
Exhaust the intermediate chamber S between the space 2 and the inner tight box 3.
The exhaust system passage L ₁ is provided, and the pressure P ₁ of the intermediate chamber S is
External pressure P ₂ and the inner Taitobo outer tight box 2
To keep the pressure lower than the internal pressure P ₃
Therefore, the gas a in the furnace and the atmosphere gas are discharged from the exhaust system passage L _1.
It is characterized in that it is configured so that the exhaust of the gas b is performed.
It

[0007]

The furnace gas a introduced to the outside of the outer tight box 2 flows into the intermediate chamber S due to the differential pressure, and the atmospheric gas b introduced to the inside of the inner tight box 3 due to the differential pressure together with impurities. It flows into the intermediate chamber S. Under these pressure relationships, the in-furnace gas a flowing into the intermediate chamber S cannot flow into the inner tight box 3 further, and the dirty atmospheric gas b flowing out into the intermediate chamber S is further outside. It is unlikely that it will flow out of the tight box 2. Then, all of them are exhausted from the intermediate chamber S directly to the outside of the furnace 1. Therefore, according to this furnace structure, it is possible to prevent the components in the furnace from being contaminated by the dirty atmospheric gas b, and moreover, the internal processing space of the inner tight box 3 can be always filled with the fresh atmospheric gas b. Further, the concentration can be set accurately because the gas a in the furnace does not flow in.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In this furnace 1, the inner space of a cylindrical furnace shell 4 having open / close doors 4a on both sides is divided by a cylindrical heat insulating material 5 having open / close portions 5a on both sides, and the inner surface of this heat insulating material 5 is divided. A rod heater 6 is provided. And this heat insulating material 5
Further inside, inside the tight box 2 made of graphite,
3 is arranged in double. The inner tight box 3 is a container x having an object to be processed in a processing space formed therein.
The outer tight box 2 that surrounds the inner tight box 3 forms an intermediate chamber S at an appropriate distance from the inner tight box 3. These tight boxes 2, 3 have their doors 2
Vent passages (not shown) for realizing differential pressure exhaust inside and outside are formed in the gaps at the four corners of a and 3a. The end plates 2a on both sides of the outer tight box 2 and one end plate 3a of the inner tight box 3 are also opening / closing doors for inserting / removing the processed material.

Then, a gas introduction system path L ₂ is connected to the external heating space of the outer tight box 2 so that a stable in-furnace gas a such as an inert gas is kept at a constant pressure or the inside of the furnace is kept at a constant pressure. flow rate adjusted by introducing the inner tight box 3 of the internal processing space atmosphere by connecting a gas introduction system path L ₃ gas b (for example, ammonia decomposition gas as; N _2,
(NH ₃ , Ar) is introduced so as to have a predetermined concentration, and the exhaust system passage L ₁ is connected to the intermediate chamber S between the outer tight box 2 and the inner tight box 3 so that the gas a, b is directly discharged to the outside of the furnace and is carried to a wax trap (not shown). In order to keep the pressure P ₁ of the intermediate chamber S relatively lower than the external pressure P ₂ of the outer tight box ₂ and the internal pressure P ₃ of the inner tight box 3, for example, P ₁ <P ₂ = P ₃ I try to satisfy the condition. Further, in this embodiment, the gas introduction path L ₃ reaches the inside of the inner tight box 3, and then the atmosphere gas b is circulated in the preheating pipe 7 routed along the load heater 6, and thereafter, the processed material is processed. The gas b is introduced into the container x containing the gas. further,
In the figure, 8 is a thermocouple for detecting the temperature in the furnace, 9 is an electrode rod for energizing the heater 6, and 10 is an electrode rod.
Is a heat insulating material interposed between the heat insulating material 5 and the furnace shell 4, and 11
Is a cooler and 12 is a fan.

With the furnace structure as described above, the in-furnace gas a introduced to the outside of the outer tight box ₂ through the gas introduction passage L ₂ flows into the intermediate chamber S due to the pressure difference, and the inner tight box The atmospheric gas b introduced into the inside of ₃ through the gas introduction system passage L ₃ flows out to the intermediate chamber S due to the differential pressure together with impurities and the like. Under these pressure relationships, the in-furnace gas a that has flowed into the intermediate chamber S is further moved to the inner tight box 3
It is impossible that the dirty atmospheric gas b that has flowed into the intermediate chamber S further flows out of the outer tight box 2. And
The gases a and b are all discharged from the intermediate chamber S to the exhaust system passage L.
_{It is} directly exhausted to the outside of the furnace ₁ through 1. Therefore, according to this furnace structure, the dirty atmosphere gas b can be discharged to the outside of the furnace without contacting the components inside the furnace, and the container x is constantly filled with the fresh atmosphere gas b. , The concentration of the gas b can be set accurately without being affected by the gas a in the furnace, and as a result,
It is possible to use a gas (corrosive gas, etc.) that adversely affects the pollution of components inside the furnace as an atmospheric gas without inconvenience, or to adjust the atmospheric gas to an optimum concentration for highly efficient processing. .

[0012]

As described above, in the vacuum furnace according to the present invention, the tight boxes are doubly arranged in the furnace, the gas in the furnace is introduced to the outside of the outer tight box, and the inside of the inner tight box is introduced. Atmosphere gas is introduced into the chamber, and those gases are exhausted from the intermediate chamber between the outer tight box and the inner tight box. Therefore, a gas (corrosive gas, etc.) that adversely affects the contamination of the components inside the furnace can be used as an atmospheric gas without any inconvenience, and it is possible to adjust the atmospheric gas to an optimum concentration for highly efficient processing. Become.

[Brief description of drawings]

FIG. 1 is a structural explanatory view for explaining the present invention.

FIG. 2 is an overall vertical sectional view showing an embodiment of the present invention.

[Explanation of symbols]

2 ... Outside tight box 3 ... Inside tight box a ... Furnace gas b ... Atmosphere gas L ₁ ... Exhaust system passages L ₂ , L ₃ ... Gas introduction passage P ₁ ... Intermediate chamber pressure P ₂ ... External pressure P ₃ ... Inside Pressure S ... Intermediate chamber

Claims (1)

[Scope of utility model registration request] 1. An outer tight box which is doubly arranged in a furnace.
Outer and inner tight boxes and outer tight box
Gas introduction system path for introducing the furnace gas to the
Gas for introducing atmospheric gas into the it box
Introductory route, outer tight box and inner tight box
And an exhaust system passage for exhausting the intermediate chamber between
The pressure in the interchamber is
To keep the pressure lower than the internal pressure of the itbox
Therefore, the exhaust of the furnace gas and atmospheric gas from the exhaust system passage
A vacuum furnace characterized in that it is configured to operate.