JPH0510677A - Degrease furnace - Google Patents

Abstract

PURPOSE:To carry out a high quality degreasing service for processed articles by laying out a conversion member, which is capable of absorbing thermal energy from a heating element and emitting far infrared rays to the processed articles, between the heating element and the processed articles. CONSTITUTION:A heat insulating material 2 is installed along the inner periphery of a chamber 1 where a heating element 3 is laid out inside the material 2. The heating element 3 is a graphite heater which is provided with a heating capacity of 400 deg.C to 800 deg.C only when degreasing is carried out. The heating element whose heating capacity is around 3000 deg.C is adopted when it is carried out up to baking. A vessel 4, which is a conversion material itself, is laid out inside the graphite heater 3. The vessel 4 is made of a graphite heater 4a on the whole. A ceramic 4b having a high emissivity of far infrared rays, is coated in the whole inner peripheral area. In this construction, the thermal energy from the graphite heater 3 is absorbed so that far infrared rays are emitted to processed articles W.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degreasing furnace suitably used for degreasing sintered molded products and metal injection molded products.

[0002]

2. Description of the Related Art Sintered molded articles are mixed with wax and binder for the purpose of ensuring moldability during molding. Therefore, it is necessary to sufficiently remove the wax content and the binder content from the processed product before sintering. Therefore, low-temperature heating is performed by a heating element in a furnace accommodating the object to be treated so that wax and binder are removed by evaporation. The furnace used for such an application is called a degreasing furnace. As the degreasing furnace, there are known a dedicated type that exclusively performs degreasing and a complex type that is configured so that subsequent sintering steps can be performed consistently in the same furnace. In the composite type, it is necessary that the heating element also has a high-temperature heating ability, and conventionally, a graphite heater or a tungsten heater, which is generally inexpensive, has been used.

[0003]

By the way, it has recently become clear that heating by far infrared rays is extremely effective in order to uniformly degrease a treated product. However, since the far infrared heater is special and expensive, it is generally difficult to use, and the graphite heater, the tungsten heater, etc. are still used for heating as in the conventional case.

The present invention does not increase the cost,
It is an object of the present invention to provide a degreasing furnace capable of performing heating with far infrared rays and thereby performing higher-quality degreasing compared with the conventional one.

[0005]

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

That is, in the degreasing furnace according to the present invention, in which the object to be treated is housed in the furnace and heated by the heating element, the heat energy from the heating element is provided between the heating element and the object to be treated. A conversion member capable of absorbing and emitting far infrared rays is disposed on the processed object side.

[0007]

With this structure, even if the heating element is a graphite heater or the like, the heat from the heating element is once absorbed by the conversion member and converted into far infrared rays there.
It will be emitted to the processed material. Therefore, according to this degreasing furnace, it is possible to degrease the processed material with high quality without using a far infrared heater.

[0008]

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

In this degreasing furnace, a heat insulating material 2 is provided along the inner circumference of a chamber 1, and a heating element 3 is arranged inside the heat insulating material 2. This heating element 3 is a graphite heater (or Dangsten heater) which has been conventionally used, and 400 ° C. to 80 ° C. when only degreasing is performed.
A material having a heating capacity of about 0 ° C. and a material having a heating capacity of about 2000 ° C. are used when sintering is performed. In the present embodiment, the container 4 having the conversion member itself is arranged inside the graphite heater 3.
The container 4 is made entirely of graphite 4a, and is coated with a ceramic 4b having a high emissivity of far-infrared rays on the entire inner circumference thereof. The container 4 absorbs heat energy from the graphite heater 3 and is housed inside. Far infrared rays can be emitted to the processed product w.

In the degreasing furnace, in order to prevent the heater 3 and the heat insulating material 2 in the furnace from being contaminated by the wax vapor generated from the processed product w during the degreasing process, the carrier gas a is caused to flow at a differential pressure. The structure is adopted. Specifically, the container 4 has a gap in a part thereof that allows the flow of gas as shown by an arrow in the figure, and is used for directly introducing the carrier gas a from the outside of the furnace. Air duct 7
And an exhaust duct 6 for directly discharging the internal gas to the outside of the furnace. Then, during the degreasing process, the container 4
The carrier gas a is introduced from the insufflation duct 7 while keeping the inside of the container at a relatively lower pressure than the outside, and at the same time, the inside of the container 4 is evacuated through the exhaust duct 6 so that the inside of the insufflation duct 7 is temporarily removed. The carrier gas a introduced to the outside and continuously flowing through the gap into the container 4 under a differential pressure can be discharged to the outside of the furnace through the exhaust duct 6 together with the wax vapor generated from the processed product w.

When a large amount of carrier gas is required, the carrier gas a is directly introduced from the outside of the furnace, so that the gas supply duct 5 may be used together.

With such a structure, even if the heating element is the graphite heater 3, the processed product w can be irradiated with far infrared rays to perform uniform degreasing with high quality. Therefore, for example, in the case of applying to a conventional furnace, it suffices to coat the inner surface of a container such as a tight box with ceramic, and the effect of easily improving the performance of the furnace can be obtained without increasing the cost. Moreover, in this embodiment,
The differential pressure flow structure prevents wax contamination in the furnace. Therefore, even if the sintering step is performed subsequent to the degreasing step, product defects are not caused, and the furnace can be used as a composite type furnace.

The conversion member is not limited to the above embodiment. For example, the whole container is made of ceramic and coated with graphite on the outside, or the ceramic layer and the graphite layer are adhered instead of the coating process if the heat transfer property is not deteriorated, or the complete 2
A structure with a heavy wall structure is also applicable. When the ceramic is excellent in far infrared ray emissivity as well as heat absorptivity, the whole container can be made of ceramic alone and the graphite layer can be omitted. Further, it is of course possible to use another material having excellent heat absorption rate and heat conductivity instead of graphite, or use another material having a high far infrared emissivity instead of ceramic. Further, when the inside of the furnace is not so concerned, for example, when the furnace is used as a degreasing furnace, it is not always necessary to make the conversion member into a closed container shape. However, even in this case, controlling the flow of the vapor can sufficiently enhance the effect of preventing contamination in the furnace. Other configurations can be variously modified without departing from the spirit of the present invention. For example, in a furnace that requires rapid heating, the configuration shown in FIG. 3 is effective. In this structure, a ceramic coating layer 12 as a conversion member is provided on the inner circumference of the heat insulating material 11, and a similar coating layer 12 is provided on the outer circumference of a graphite heater 13 as a heating element arranged in the heat insulating material 11. Far infrared rays can be directly emitted from the heater 13 to the processed object w, and further far infrared rays can be emitted from the inner circumference of the heat insulating material 11 to enhance the heating effect. You can Further, as shown in FIG. 4, when a graphite container 22 having a multistage shelf structure is arranged at the center of a graphite heater 21 which is a heating element, this container 22
A ceramic coating layer 23 may be provided on the inner surface of the above and on the surface of the shelf plate 22a to serve as a conversion member as a whole.

[0014]

As described above, the degreasing furnace according to the present invention converts the heat energy of the heating element into far infrared rays through the conversion member and radiates the far infrared rays to the object to be treated. Therefore, even if the heating element is a conventionally used graphite heater or the like, it is possible to perform high-quality degreasing on the processed material.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing an embodiment of the present invention.

2 is a cross-sectional view of FIG.

FIG. 3 is a diagram corresponding to FIG. 2 showing another embodiment of the present invention.

FIG. 4 is a view corresponding to FIG. 1 showing still another embodiment of the present invention.

[Explanation of symbols]

 w ... Treated product 3, 13, 21 ... Heating element (graphite heater) 4, 22 ... Conversion member (container) 12 ... Conversion member (ceramic coating layer)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kei Honda Honda, No. 1 Kuwabara-cho, Nishinokyo, Nakagyo-ku, Kyoto Shimadzu Corporation Sanjo Factory

Claims (1)

Claim: What is claimed is: 1. In a degreasing furnace in which a processed material is housed in a furnace and heated by a heating element, heat energy from the heating element is applied between the heating element and the processed object. A degreasing furnace having a conversion member arranged to absorb and radiate far infrared rays on the processed object side.