JPH03191293A - Processing of binder - Google Patents

Abstract

PURPOSE:To minimize the contamination of a vacuum pump due to a non- decomposed binder by providing a combustion device for a binder between a vacuum sintering furnace and the vacuum pump, and decomposing a vaporized binder by combustion reaction by mixing oxygen gas of gas involving oxygen into the vaporized binder. CONSTITUTION:There is provided a combustion device 11 interposed in an evacuation pipe line 8 at a location on the later stage side of a wax cathcher 10 but on the front stage side of a vacuum pump 9. Combustion reaction gas is mixed into the combustion device 11 for combustion of a vaporized binder. As a result of combustion reaction, the vaporized binder is substantially completely decomposed. Decomposed gas and gas produced in decomposition of the vaporized binder is carried to the vacuum pump 9 and exhausted through the same. In this case, since the gas passing through the vacuum pump 9 is one substantially completely decomposed, there is no fear of it's contaminating lubrication oil in the vacuum pump 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for treating vaporized binder produced when a material to be sintered is sintered in a vacuum sintering furnace.

[Conventional Technique 11i] When the binder vaporized from the object to be sintered is sucked and exhausted by a vacuum pump in a vacuum sintering furnace, the undecomposed binder becomes liquefied or solidified as it cools in the path leading to the vacuum pump. However, these can accumulate in the middle of piping or clog vacuum pumps, causing various problems. Conventionally, therefore, the binder is heated in a heating device provided between the vacuum sintering furnace and the vacuum pump to ensure complete decomposition.

[4 Problems to be Solved by the Invention] This conventional binder treatment method has the problem that the decomposition of the binder is slow because the decomposition of the binder is caused by heating. This means that the binder must be kept in the heating ALL for a long time in order to undergo complete decomposition, which poses the problem of requiring an enlarged heating apparatus. Further, if the heating device is small and insufficient, there is a problem in that some of the binder passes through the heating device undecomposed, causing the same problems as described above.

The present invention has been made to solve the above-mentioned problems (technical problems and technical problems in the conventional technology), and involves mixing oxygen gas or oxygen-containing gas into the undecomposed binder to cause decomposition by a combustion reaction. It is an object of the present invention to provide a method for treating binder, which speeds up the progress of decomposition, thereby making it possible to complete the decomposition and downsize the incinerator.

[Means for Solving the Problems] In order to achieve the above object, the present invention takes the measures as described in box R of the above claims, and its effects are as follows.

C action] The jl'cf binder discharged from the vacuum sintering furnace is mixed with oxygen gas or a gas containing # element, and the binder is decomposed by a combustion reaction. The decomposed gas is then transported to a vacuum pump.

[Example] The drawings showing the embodiments of the present application will be described below.

1 indicates a well-known vacuum sintering furnace, which is composed of members indicated by numerals 2 to 5. S, 2 is the furnace body, 3 is the insulation wall, °
The inside is a sintering chamber. Reference numeral 4 denotes a support base for the object to be sintered, 5 a heater for heating, and 6 the object to be sintered, which is formed by molding and solidifying powdered metal using a well-known binder. Next, reference numeral 7 indicates a binder processing equipment in which the furnace body 2 is provided with a + sign, and this will be explained below. Reference numeral 8 denotes an exhaust pipe line, one end of which is connected to the furnace body 2. 9 is a vacuum pump connected to the other end of the exhaust pipe line 8. Reference numeral 10 denotes a well-known wax catcher (mechanical trap) interposed in the middle of the exhaust pipe 8, but this may not be provided in some cases. Reference numeral 11 denotes a combustion device which is made of dipped copper and is disposed in the exhaust pipe line 8 in a device which is located at a stage before the vacuum pump 9 and which is made of dip copper compared to the wax catcher 10 .

Reference numeral 12 denotes a supply source of combustion reaction residue connected to the combustion device 1. As the combustion reaction gas, oxygen scum or a gas containing [e (for example, water vapor X) is used.

13 is the heater installed in the combustion engine t11, which is the source 1
4b) generates heat by supplying power.

The action in the binder removal step when the object to be sintered 6 is sintered using the vacuum sintering furnace 1 is as follows.

The object to be sintered 6 is heated by the heater 5 . Due to this heating, part of the binder contained in the material to be sintered 6 decomposes into a gas (e.g., hydrogen, carbon oxide, nitrogen oxide, methane, which is a gas at room temperature), and the other part It just vaporizes.

The decomposed gas and the vaporized binder are conveyed from the vacuum sintering furnace 1 to the exhaust line 8 by the suction of the vacuum pump. Those transported to the exhaust pipe 8 are first passed through the wax catcher lO.
At this point, components of the vaporized binder with relatively large molecular weights are removed by liquefaction or solidification.
Next, the remaining part of the cracked gas and the electrified binder is
It reaches ull.

Combustion device 1! In the process, gas for combustion reaction is mixed into them, and the vaporized binder is combusted. As a result of the combustion reaction, the vaporized binder is almost completely decomposed. Since this decomposition is due to a combustion reaction using oxygen, the decomposed gas is oxygen compounds such as H2O, Co, and CO□. If the inside of the combustion device 11 is relatively low temperature, it is preferable to raise the temperature by generating heat from the heater 13 to ensure the combustion of the decomposed residue and the gas IF.

The gas generated by the decomposition of the binder is pumped into the vacuum pump 9.
and is discharged through it. In this case, since most of the gas passing through the vacuum pump 9 is completely decomposed gas, clogging of the vacuum pump 9 or contamination of the lubricating oil of the vacuum pump 9 is minimal.

When the binder is treated as described above, the wax (binder) is not removed by the wax catcher IO, so the volumetric expansion rate due to the decomposition of the binder at the combustion #I position is small.

For this reason, if the IK efficiency of the vacuum pump 9 is good, but the pump 9 has sufficient wandering ability, the wax catcher 1
0 can also be omitted.

As an inland embodiment, a mechanical 7-star may be inserted in the part indicated by the symbol A.

[Effects of the Invention] As described above, in the present invention, when the binder vaporized from the vK sintered material 6 is sucked and discharged by the vacuum pump 9, the binder is decomposed and the decomposed gas is transferred to the vacuum pump. 9, it has the effect of minimizing contamination of the vacuum pump by undecomposed binder and extremely reducing the frequency of maintenance of the vacuum pump.

Moreover, when the binder is decomposed, the decomposition is as follows.
Since it is carried out through a combustion reaction, it has the advantage of proceeding extremely quickly. Therefore, when the binder is decomposed while passing through the combustion device 11, the decomposition can be completed while the binder travels a short distance. This has the effect that the length dimension (dimension in the flow direction of the binder) of the combustion device 11 can be reduced (miniaturized).

Furthermore, even if the size of the fuel #I device 11 is reduced in size, the decomposition of the binder is highly reliable, and there is an effect that the above-mentioned contamination prevention can be ensured.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a schematic diagram of a vacuum sintering apparatus. I...Vacuum sintering furnace, 6...Sintered object, 9...Vacuum pump, 1! ...Combustion device.

Claims (1)

[Claims] In a binder processing method in which the binder vaporized from the object to be sintered in a vacuum sintering furnace is sucked and discharged by a vacuum pump connected to the vacuum sintering furnace, there is a space between the vacuum sintering furnace and the vacuum pump. A binder combustion device is provided, and in the combustion device, oxygen gas or a gas containing oxygen is mixed into the vaporized binder, the vaporized binder is decomposed by a combustion reaction, and the decomposed gas is sucked by the vacuum pump. A method for processing a binder, characterized by discharging the binder.