JPH0422831Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention relates to a horizontal atmosphere furnace. More specifically, the present invention relates to a horizontal atmospheric furnace in which a sample, such as nitriding a sample, is processed in a high-temperature air stream, and in which the air stream moves horizontally.

(B) Prior Art Conventionally, methods are known in which a sample is heated while being brought into contact with a mixed gas of two or more different specific gravities, such as nitriding a sample with a mixed gas of ammonia gas and nitrogen gas. Specifically, in order to ensure the uniformity of the mixed gas, a method is used in which the mixed gas is introduced into a heated atmosphere and brought into contact with the sample, which is left still in this atmosphere, while moving the gas in the horizontal direction. The device for this purpose is to use a gas supply unit that mixes and supplies the intended gases, and a gas inlet of a heating furnace that is arranged horizontally, with a gas inlet at one end and a gas outlet at the other end. A horizontal atmosphere furnace is known which is configured so that a mixed gas can be introduced into the heating furnace by being connected to the heating furnace, and the gas can be discharged from a gas outlet at the other end.

The heating furnace of this atmosphere furnace is composed of a cylindrical furnace core tube installed horizontally, a heating means installed concentrically around the core tube, and a heat insulating material installed concentrically around the core tube. The inside of the furnace core tube is maintained in a heated atmosphere by a heating means, the sample is left still in this heated atmosphere, and the target mixed gas is moved horizontally inside the furnace tube and brought into contact with the sample, and then the above-mentioned flow is The sample was processed by flowing out from the outlet.

(c) Problems to be solved by the invention However, in the above-mentioned horizontal atmosphere furnace,
The thin tube that forms the gas inlet has a gas discharge port near the inner end of the core tube with the diameter of the tube, and when the combined and mixed gases flow into the core tube from this discharge port, gases with low specific gravity are discharged from the core. Gas with a high specific gravity at the top of the tube tends to separate and collect at the bottom of the furnace tube, making it difficult to maintain a uniform mixed gas atmosphere, making it difficult to carry out the desired reaction efficiently, and resulting in waste of sample and mixed gas. was.

This idea was developed in view of the circumstances surrounding this idea, and in particular, the inlet for the mixed gas was extended into the interior of the reactor core tube, and the mixed gas was discharged in a uniformly mixed state at the extended tip, allowing the sample to be sampled. The present invention aims to provide a horizontal atmosphere furnace that is configured to be able to come into uniform contact with the

(d) Means for solving the problem Thus, according to this invention, a cylindrical sample heating furnace with a gas outlet at one end and a heating means attached to the outer periphery is arranged horizontally, and two or more types with different specific gravities are heated. A narrow tube for introducing gas is formed by extending from a gas supply section for supplying a mixture of gases and having a large number of gas discharge holes drilled in the side circumference of the tip end, and the group of gas discharge holes is arranged in the sample heating furnace. A horizontal atmosphere furnace is provided, which is characterized in that it is inserted and connected to the sample heating furnace.

The gas introduction capillary used in this invention extends to a position where the mixed gas can be released into the intended heated atmosphere. The shape of this extended thin tube in the atmosphere furnace is not particularly limited, and may be rod-shaped.
Further, at least a portion thereof may be coiled.
Furthermore, the cross-sectional shape of the thin tube may be semicircular, circular, rectangular, or the like.

A large number of small holes for releasing the mixed gas are bored at the tip of the gas introduction thin tube. Each of the above-mentioned small holes is bored to uniformly disperse the mixed gas. For example, when the thin tube extending portion is rod-shaped, in one cross section of the thin tube, the small holes are formed in a straight direction from the center of the tube to the outside of the tube. Preferably, the holes are formed in a large and radial manner. The specific optimal position of the gas release hole varies depending on the insertion position of the above-mentioned thin tube into the heating furnace, but this thin tube is fixed at the bottom of the heating furnace, and gas is released upward from this thin tube. It is preferable to drill a group of gas discharge holes such that the gas discharge holes can be separated from each other by gravity after discharged mixed gases having different specific gravities.

The gas supply section used in this invention usually has a branch section that can merge and mix two or more gases with different specific gravities, and the gas introduction thin tube is connected to this branch section.

Note that the sample may be introduced by providing a sample inlet that can be opened and closed, or may be introduced using a gas outlet of the heating furnace. Further, a sample mounting table capable of holding or supporting a sample may be provided inside the heating furnace. In this case, the mounting table is preferably made of corrosion-resistant material such as stainless steel.

(E) Effect According to this invention, two or more gases having different specific gravities that have merged and been introduced into the capillary, flow when they flow out from the group of discharge holes drilled on the side circumference at the tip of the capillary. Due to the sudden change in the line direction, a turbulent flow occurs within the tip of the capillary, and the mixture is evenly mixed and then uniformly dispersed in the atmosphere furnace.

This invention will be explained in detail below with reference to examples, but the invention is not limited thereby.

(F) Embodiment FIG. 1 is an explanatory diagram of the configuration of a horizontal atmosphere furnace as an example of this invention.

In the figure, 1 is a thin tube for gas introduction, 2 is a furnace core tube,
3 and 4 are rubber plugs, 5 is a gas outlet pipe, and 6 is a heat insulating material for insulating a heating means (not shown) attached to the furnace core tube from the outside.

Insert the gas introduction thin tube (inner diameter 10 mm) 1 to the center of the furnace core tube (inner diameter 50 mm, length 70 cm) 2, and with the gas introduction thin tube 1 in contact with the inner lower part of the furnace core tube 2, insert the rubber stopper 3. At the same time, this rubber stopper 3 is fitted into the right end opening of the furnace core tube 2 to prevent gas from flowing out from this end.

In addition, the left end port of the reactor core tube 2 is hermetically sealed with a similar rubber stopper 4, and a gas outlet pipe 5 is communicated with the inside of the reactor core tube 2 by passing a thin tube through the center of the rubber stopper 4.
is provided.

A branch pipe 7 is connected to the portion of the thin gas introduction tube 1 exposed from the atmosphere furnace, and this branch pipe further contains cylinders (not shown) for each intended gas (for example, ammonia gas, nitrogen gas, etc.). is connected.

FIG. 2 shows details of the structure of the tip of the gas introduction thin tube 1. As shown in FIG.

According to this figure, the tip of the thin tube 1 is sealed, and eight groups of discharge holes for gas discharge are provided in three rows in parallel from the side surface to the top surface of the tube body at the rear thereof.

These 8 groups of discharge holes are arranged at the same interval a on each row.
(5 mm in this example), and as shown in the cross-sectional view taken along the line A-A in the same figure, small holes (hole diameter: 1mm) are drilled radially.

Next, nitriding treatment of a fibrous sample (glass) using this horizontal atmosphere furnace will be explained.

First, a sample is placed on top of the group of gas discharge holes at the tip of the gas introduction thin tube, and then this thin tube is inserted into the furnace, and the thin tube is fixed with a gum stopper and the furnace core tube is sealed. An ammonia gas cylinder is connected to one of the branch pipes connected to this thin tube, and a nitrogen gas cylinder is connected to the other. Open each gas cylinder and adjust with each flow meter to make ammonia:nitrogen = 2:1.
With the mixed gas flowing into the heated atmosphere furnace, the temperature inside the furnace is raised to 1000°C at a rate of 3°C/mim.
This allows efficient nitriding of the sample (glass).

(G) Effects of the invention According to this invention, two or more types of reaction gases having different specific gravities can be supplied into the atmosphere furnace in a uniformly mixed state. Moreover, since this uniformly mixed gas is extended and released near the sample, it can be efficiently brought into contact with the sample.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of a horizontal atmosphere furnace according to an embodiment of this invention, and FIG. 2 is an explanatory diagram illustrating the state of a group of discharge holes formed at the tip of a thin gas introduction tube. 1... Thin tube for gas introduction, 2... Furnace core tube, 3, 4
...Rubber stopper, 5...Gas outflow pipe, 6...Insulating material for insulating the heating means attached to the reactor core tube from the outside, 7
...branch pipe, 8...discharge hole.

Claims (1)

[Scope of utility model registration request] A cylindrical sample heating furnace with a gas outlet at one end and a heating means attached to the outer periphery is arranged horizontally, and is extended from a gas supply section that mixes and supplies two or more types of gases with different specific gravity, and is installed around the side of the tip. A horizontal atmosphere characterized in that a gas introduction thin tube having a large number of gas discharge holes bored therein is inserted and connected to the sample heating furnace so that the group of gas discharge holes is arranged in the sample heating furnace. Furnace.