JPS60141822A - Atmosphere heat treating furnace provided with vacuum vestibule - Google Patents

Abstract

PURPOSE:To provide a titled atmosphere heat treating furnace which decreases the consumption of a gaseous atmosphere for restoring pressure in vacuum vestibules by the constitution in which a vacuum charging vestibule and a vacuum discharging vestibule are connected and communicated with each other by an atmosphere conduit provided with stop valves. CONSTITUTION:A vacuum charging vestibule 4 and a vacuum discharging vestibule 5 provided before and behind the furnace body 1 of an atmosphere heat treating furnace T are connected by an atmosphere conduit 14 having stop valves 12, 13. The atmosphere such as N2 or the like in the vestibule 4 after charging of a material to be treated into the furnace body 1 or the atmosphere in the vestibule 5 before discharging of the treated material to the outside of the furnace is used via said conduit 14 as the gas for restoring the pressure in the other vestibule in the stage of restoring the pressure therein after evacuation of said vestibule to a vacuum by opening the above-mentioned valves 12, 13, by which the consumption of the atmosphere for restoring the pressure in the respective vestibules is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an atmospheric heat treatment furnace equipped with a vacuum bestible.

Conventionally, during heat treatments such as carburizing, annealing, and sintering under reduced pressure or pressurized atmospheres, vacuum charging bestibles and vacuum extraction bestibles have been used to prevent contamination of the furnace atmosphere and reduce purge gas consumption. In an atmosphere heat treatment furnace, when the material to be treated is loaded into the furnace, the material to be treated is placed in the charging bestible and the inside of the charging bestible is evacuated.On the other hand, when the material to be treated is transferred to the extraction bestible, the inside of the extraction bestible is evacuated. The inside of the vestible is evacuated, then the pressure is restored with a specified atmospheric gas, and processing materials are loaded into the furnace and extracted from the furnace.
Since the atmosphere in each bestible during one cycle of charging and extracting processing materials is evacuated as is, there is a drawback that a large amount of atmosphere gas for repressurization is required.

In the present invention, in the atmospheric heat treatment furnace, when one bestible has completed evacuation and the other bestible is in a predetermined pressure recovery state corresponding to the furnace pressure 1 due to the supply of atmospheric gas, By connecting both bestibles and making them at the same pressure, a part of the atmosphere of one bestible is used as the atmosphere for repressurization of the other bestible, and a vacuum bestible is created that can reduce the consumption of atmosphere gas for repressurization. The purpose of the present invention is to provide a heat treatment furnace with a high atmosphere.

In order to achieve the above object, the present invention is characterized in that the vacuum charging bestible and the vacuum extraction bestible are connected by an atmosphere conduit, and the atmosphere conduit is provided with an on-off valve.

Next, the present invention will be explained with reference to drawings which are one embodiment.

FIG. 1 shows an atmospheric heat treatment furnace T according to the present invention.
is the main body of the atmospheric heat treatment furnace to which atmospheric gas according to the processing purpose is supplied, and the furnace interior entrance door 2. A vacuum charging bestible 4 and a vacuum extraction bestible 5 are provided on both sides with an in-furnace extraction door 3 interposed therebetween. In addition, 6a.

7a is the charging door of Vacuum Bestible 1.5, 61), 71
) is an extraction door.

The vacuum charging bestible 1 and the vacuum extraction bestible 5 have atmospheric gas introduction valves 8 and 9, and are also connected to a N2 gas source, which is a gas for restoring pressure, through atmospheric gas introduction valves f') and 11 for atmospheric gas for repressurization. On the other hand, a vacuum valve (opening/closing valve) 12.
13, and each vacuum valve 12. ] 3 is a vacuum exhaust system g via the main vacuum valve 15.
]6. Note that N2 is used as the gas for pressure recovery.
In addition to the gas, other atmospheric gases such as A'r gas, endothermic gas, etc. may be used depending on the atmosphere in the furnace.

The second section regarding the operation of the atmospheric heat treatment furnace T having the above configuration.
I'll explain if I want to make a diagram.

Mainly, the treated material Wn which has been subjected to a predetermined heat treatment is extracted into the vacuum extraction bestible 5, and the inside of the bestible 5 is heated to a predetermined bestable pressure (in tens of i) by introducing atmospheric pressure (N, gas).
The processing material Wo is charged into the vacuum charging vestible 4, and the inside of the vestible 4 is evacuated to a predetermined vacuum (approximately 10 to 10 Torr).
(Fig. 2A), the main vacuum valve 15 is closed, the vacuum valves 12 and 13 are opened, and each vesnable
1 and 5 are in communication, the atmosphere inside the vacuum extraction bestible 5 is supplied to the vacuum charging bestible 4 through the atmosphere conduits 1 and 11 due to the pressure difference, and initial pressure is restored (
Figure 20).

Thereafter, the vacuum valves 12 and 13 are closed, and the atmosphere introduction valve 10 and the atmosphere introduction valve 9 are opened to supply atmospheric gas into the vacuum charging bestible 4 to reach a predetermined bestible pressure (+- number ++un H20). At the same time, atmospheric pressure is introduced into the vacuum extraction bestible 5 (the pressure is restored to near atmospheric pressure (Fig. 28)).

Next, the extraction door 61], the furnace entrance door 2, and the extraction door 7 are opened, and the processed material No. 7 in the vacuum charging bestible 4 is poured into the furnace body 1, and the processed material in the vacuum extraction bestible 5 is poured into the furnace body 1. Extract Wn outside the furnace. After that, the atmosphere inlet valve 9 is left open, the main vacuum valve 15 and the vacuum valve 13 are opened, and the inside of the vacuum extraction bestible 5 is evacuated to a predetermined vacuum (FIG. 22). Next, the main vacuum valve 15 is closed and the vacuum valve 12 is opened, and as described above, the atmosphere inside the vacuum charging bestible 1 is supplied to the vacuum extraction bestible S to perform initial pressure restoration (Figure 2 E). After that, the vacuum valves 12 and 13 are closed, and the atmosphere introduction valve 11. The atmosphere inlet valve 8 is opened, and the pressure inside the vacuum charging bestible 4 is restored by introducing flame, and the pressure inside the vacuum extraction bestible 5 is restored by supplying atmospheric gas (see Figure 2). A new processing material W is charged into the vacuum extraction bestible 5, and a heat-treated processing material Wn-] is charged into the vacuum extraction bestible 5 (FIG. 2). Then, the vacuum valve 12 and the main vacuum valve 15 are opened to place the interior of the vacuum charging bestible 1 under vacuum, resulting in the state shown in FIG. 2A, and the same operations are performed thereafter.

In the above embodiment, the vacuum evacuation device 1 = 4-6 was installed, and the evacuation pipe was also used as the atmosphere conduit 14, or each bestible 4.5 was provided with a vacuum evacuation device, and An atmosphere conduit may be provided separately. Further, the atmospheric air introduction valve 8 is not necessarily provided if the internal pressure of the bestible 4.5 returns to near atmospheric pressure when the bestibles 1.5 are in communication.

As is clear from the following explanation, when going up to the atmosphere heat treatment furnace according to the present invention, the vacuum charging bestible and the vacuum extraction bestible are connected through an atmosphere conduit having an on-off valve, so the exhausted bestible By opening the on-off valve, the atmosphere inside the furnace, that is, the atmosphere inside the vacuum charging bestible after charging the processing material into the furnace, or the atmosphere inside the vacuum extraction bestible before extracting the processing material outside the furnace. 1) Since it is used as a depressurizing gas when the Ikekata Bestible is depressurized after being evacuated, the amount of atmospheric gas used for vacuum charging and extracting the Bestible can be reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an atmospheric heat treatment furnace equipped with a vacuum bestible according to the present invention, and FIGS. 2A to 2D are explanatory diagrams of a method of operating the vacuum bestible. 1...Furnace body, 4...Vacuum charging bestible, 5...
・Vacuum extraction bestible, 12.13...Opening/closing valve (vacuum valve), 1.1...Atmosphere conduit. Patent applicant: Chugai Roko Kogyo Co., Ltd. Agent: Patent attorney: Aoyama Two idiots 7- Figure 1! 1

Claims (1)

[Claims] (1) An atmosphere heat treatment furnace equipped with a vacuum charging bestible and a vacuum extraction bestible, characterized in that each of the bestibles is connected by an atmosphere conduit, and the atmosphere conduit is provided with an on-off valve. Atmospheric heat treatment furnace.