JP2916686B2 - Gas supply device for cooling of vacuum heating furnace - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gas supply device for cooling a vacuum heating furnace. More specifically, the present invention relates to a method for heating a metal in a vacuum furnace and then heating the metal to a predetermined temperature. The present invention relates to a device for supplying a cooling gas used for lowering.

[Conventional technology]

Heat treatment of the metal, for example, quenching, solution treatment, annealing, tempering, brazing, etc., is performed under reduced pressure using a vacuum heating furnace in order to avoid oxidation of the metal to be treated. Then, in order to lower the temperature inside the furnace after the treatment to a predetermined temperature, a gas such as hydrogen, helium, nitrogen or argon is supplied into the vacuum heating furnace as a cooling medium so as to avoid oxidation and contamination of the metal to be treated. Have gone. This cooling gas is usually filled under pressure to speed the cooling. And when the inside of the furnace drops to a predetermined temperature, the cooling gas contains various impurity components that are deaerated from the heat-treated metal,
It is discharged from the furnace and is normally released to the atmosphere.

[Problems to be solved by the invention]

However, the above-mentioned cooling gas is an expensive gas, and the amount of the gas used is extremely large when used under high pressure as described above in order to speed up the cooling, resulting in an increase in processing cost. It will be. Therefore, even though expensive gases such as helium in particular can be understood to be very effective as cooling gases for metals,
It was economically impeding its willingness to use.

In view of the above situation, the present invention aims to collect and reuse exhaust gas containing impurity components after being used for cooling the vacuum heating furnace without dispersing the exhaust gas to the atmosphere, It is an object of the present invention to provide a cooling gas supply device for a vacuum heating furnace that can use the gas at a lower cost.

[Means for solving the problem]

In order to achieve the above object, a cooling gas supply device for a vacuum heating furnace according to the present invention has, as a first configuration, a vacuum exhaust system having a heater for heating the inside of a furnace and an exhaust unit for evacuating the inside of the furnace. A gas supply system comprising a pipe connecting the vacuum heating furnace and a storage tank storing the cooling gas, which is a device for supplying a cooling gas to a vacuum heating furnace provided with:
A gas recovery system including a compressor having a discharge port opened and opened in a direction opposite to the flow of gas in the gas supply system, in a pipe connected at both ends to the gas supply system, and one end. Supply gas pressurization connected to the discharge port side of the compressor of the gas recovery system, and the other end connected to the vacuum heating furnace side of the vacuum recovery furnace side branch of the gas recovery system of the gas supply system. And a gas purifying means such as a catalyst tube or an adsorption tube is disposed in a pipeline of the gas recovery system.

Further, the second configuration includes a gas supply system configured in the same manner as the first configuration, a gas recovery system having no gas purification unit, and a supply gas pressurization system similar to the first configuration. And a recovery gas purification system provided with gas purification means such as a catalyst tube and an adsorption tube in a pipe connecting the storage tank and the suction port side of the compressor arranged in the gas recovery system. I have.

〔Example〕

Hereinafter, the present invention will be described in more detail based on embodiments shown in the drawings.

First, FIG. 1 shows the first embodiment, and shows one embodiment in which the first configuration of the device of the present invention is applied.

The vacuum heating furnace 1 is generally used for heat-treating a metal under vacuum, and is formed so as to be airtightly surrounded by insulated furnace walls 2. A heating element 3 such as a heater and a stirring fan 4 for stirring the inside of the vacuum heating furnace 1 are provided. A cooling water pipe 5 and a pressure gauge 6 for measuring the pressure in the vacuum heating furnace 1 are arranged on the furnace wall 2. Such a vacuum heating furnace 1 is provided with a vacuum exhaust system 7 which penetrates the furnace wall 2 in a gas-tight manner and communicates with the inside of the furnace, and is provided with a valve 8, a diffusion pump 9, a rotary pump 10, and the like. . The metal to be heated A is carried into and out of the furnace by the basket 11.

The cooling gas supply device for a vacuum heating furnace according to the present invention supplies a cooling gas to the furnace for cooling the furnace after heat-treating the metal under vacuum in the vacuum heating furnace 1 having such a configuration. A cooling gas comprising one or a mixture of two or more gases selected from gases such as hydrogen, nitrogen, helium, argon, etc., is supplied from the storage tank 12 to the vacuum heating furnace 1;
The cooling gas after cooling is collected in the storage tank 12.

The storage tank 12 is connected to the vacuum heating furnace 1 by a gas supply system 17 including a pipe 16 in which valves 13, 14 and 15 are arranged. still,
In the following description, the storage tank 12 side is referred to as upstream, and the vacuum heating furnace 1 side is referred to as downstream based on the gas flow in the gas supply system 17.

One end of the gas supply system 17 is connected to the valve 13 of the pipe 16.
Downstream from the valve via a valve 18 and the other end
Downstream of the 16 valves 14, there is provided a side pipe 20 branched via a valve 19 and having a flow end connected to the pipe 16 of the gas supply system 17. A compressor in which a discharge port is disposed between the valve 18 and the valve 19 of the side pipe line 20 with a discharge port opened in a direction facing the flow of gas in the gas supply system 17, that is, a discharge port. 21 are provided. Further, a valve 22 is provided on the discharge port side of the compressor 21, and a catalyst tube 23 filled with a platinum catalyst, a palladium catalyst, or the like, and a silica gel, alumina, zeolite, molecular sieve, etc. And an adsorption cylinder 24 filled with the adsorbent, these valves 19, the compressor 21, the valve
A gas recovery system 25 is constituted by a side pipe line 20 provided with 22, a catalyst tube 23, an adsorption tube 24, and a valve 18 in that order.

Note that it is convenient for continuous operation if a plurality of catalyst tubes 23 and adsorption tubes 24 are provided in parallel and operated by alternately switching the use and regeneration steps.

Further, a pipe 26 is branched between the compressor 21 and the valve 22 of the gas recovery system 25, that is, on the discharge port side of the compressor 21. The other end of the pipe 26 is connected via a valve 27 to the downstream side of the valve 15 in the line 16 of the gas supply system 17, that is, between the valve 15 and the vacuum heating furnace 1. The supply gas pressurizing system 28 is constituted by the valve 27.

 Next, an operation method of the above-described embodiment apparatus will be described.

First, the metal A to be treated is placed in the basket 11 and housed in the vacuum heating furnace 1 to be sealed. Then, the rotary pump 10 and the diffusion pump 9 are operated and the valve 8 is opened to evacuate the vacuum heating furnace 1. To a predetermined degree of vacuum. When a predetermined degree of vacuum is reached, the heater 3 is operated, the temperature inside the furnace 1 is raised while maintaining the vacuum, and the metal A to be processed is heat-treated under conditions according to the desired heat treatment. During this time, cooling water is supplied to the cooling water pipe 5. And when the desired heat treatment is completed,
The heater 3 is stopped, the valve 8 is closed, and the diffusion pump 9 is closed.
Then, the vacuum rotary pump 10 is stopped to shut off the vacuum heating process.

As described above, when the predetermined vacuum heating process is completed,
13, the valve 14 and the valve 15 are sequentially opened (the other valves are closed), the storage tank 12 is connected to the vacuum heating furnace 1, and the cooling gas stored in the storage tank 12 is supplied to the gas supply system 17 by the pressure difference. To cool the inside of the furnace by introducing it into the vacuum heating furnace 1.

This cooling gas flows until the pressure in the storage tank 12 and the vacuum heating furnace 1 equilibrates. When the pressure in the vacuum heating furnace reaches a predetermined pressure, the valves 13, 14, and 15 are closed to stop the gas supply. Both pressures are measured by pressure gauges 6, 29 provided respectively. Even if the pressure of the vacuum heating furnace 1 is balanced with the pressure of the storage tank 12, when the pressure does not reach the predetermined pressure,
The valve 15 is closed, the valves 19 and 27 are opened, and the compressor 21 is driven, and the cooling gas in the storage tank 12 is sucked by the compressor 21 through the valves 13, the valves 14 and the valve 19, and is compressed. The gas is supplied to the vacuum heating furnace 1 through a pipe 26 of a supply gas pressurizing system 28 via a gas supply line 27, and is filled with cooling gas under pressure until the inside of the furnace reaches a predetermined pressure. In general, in gas cooling, the higher the pressure, the faster the cooling and the more efficient the processing operation.

When the cooling gas is pressurized and filled to a predetermined pressure in the vacuum heating furnace 1 in this manner, the valves 27 and 19 are closed, the compressor 21 is stopped, and the supply of the cooling gas to the vacuum heating furnace 1 is performed. stop. Then, the stirring fan 4 is driven to stir the inside of the furnace to promote cooling. In addition, the pressure in the furnace decreases with the progress of cooling, but at this time, the valves 13, 14, 14, 19, and 27 are opened as appropriate, and the compressor 21 is driven to supply the pressurized gas pressurized system 28 from the storage tank 12. The cooling gas may be successively pressurized and supplied to the vacuum heating furnace 1 by using.

When the temperature in the vacuum heating furnace 1 drops to a desired temperature (for example, a temperature at which the processing metal can be carried out), the stirring fan 4 is stopped. And vacuum heating furnace 1
While the pressure of the storage tank 12 is higher than the pressure of the storage tank 12, the valve 27, the valve 22, the valve 18,
Open the valve 13 and supply gas in the vacuum heating furnace 1 to the gas pressurizing system
The gas is collected in the storage tank 12 through the catalyst tube 23 and the adsorption tube 24 of the gas recovery system 25 and the gas recovery system 25. Next, when the pressures in the vacuum heating furnace 1 and the storage tank 12 are balanced, the valve 27 is closed, the valves 15 and 19 are opened, and the compressor 21 is driven. Then, the cooling gas in the vacuum heating furnace 1 is recovered in the storage tank 12 via the gas recovery system 25. The cooling gas recovered through the gas recovery system 25 contains oxygen, moisture, and other impurity components as a result of being used for cooling in the vacuum heating furnace 1. The gas is removed by passing through the catalyst tube 23 and the adsorption tube 24, which are purification means, and is recovered in the storage tank 12 as purified high-purity gas.

In addition, a side pipe 32 having valves 30 and 31 with a valve 19 of a pipe 20 on the suction side of the compressor 21 of the gas recovery system 25 is provided, and a vacuum pump 33 is provided in the side pipe 32. And close valve 19 to close valve 30,
By opening the valve 31 and cooperating with the vacuum pump 33 and the compressor 21, the gas can be collected until the inside of the vacuum heating furnace 1 is reduced in pressure (for example, 10 Torr), and the collection efficiency can be improved. . In addition, it is also possible to arrange appropriate auxiliary equipment such as a heating means and a cooling means at an appropriate position in each pipeline to improve the efficiency of recovery and purification.

When nitrogen, helium, or argon is used as a cooling gas, an appropriate amount of hydrogen is added to these gases, about 4% or less.
When used in an amount of preferably 0.1 to 1%, heat transfer for cooling in the vacuum heating furnace 1 is promoted, and oxygen degassed from the treated metal or oxygen leaked in the treatment system is subjected to water reaction. This is convenient for metal heat treatment because it can be removed by changing to.

As described above, the cooling gas from which impurities have been removed is collected and stored in the storage tank 12, and this cooling gas is used for cooling the next metal heat treatment. As described above, according to this embodiment, the cooling gas can be repeatedly used, the cost of the gas can be reduced, and expensive helium or the like can be used. Further, when the cooling gas disappears due to repeated use and the recovery amount decreases, the storage tank 12 may be appropriately refilled from a separate gas source such as a cylinder 34 attached to the storage tank 12.

Next, FIG. 2 shows a second embodiment to which the second configuration of the present invention is applied. The same elements as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

This embodiment is different from the first embodiment in that the gas recovery system 25
The gas purification means, such as the catalyst tube 23 and the adsorption tube 24, provided in the system is made independent of another system. That is, the storage tank 12
And a valve on the suction port side of the compressor 21 of the gas recovery system 25
19 through a valve 40, a valve 41 and a pipe 42, and the pipe 42
The catalyst cylinder 23 and the adsorption cylinder 24 are arranged between the valve 40 and the valve 41 to constitute a recovered gas purification system 43.

In the present embodiment, a cooling gas is supplied to the vacuum heating furnace 1 by the same operation as in the first embodiment, and the cooling gas from the vacuum heating furnace 1 after cooling is first supplied to the valve 27, the valve 22, Valve 18, Valve 13
To recover the gas in the storage tank 12 via the supply gas pressurizing system 28 and the gas recovery system 25 until the pressure in the vacuum heating furnace 1 becomes equilibrium with the pressure in the storage tank 12. Then, when the equilibrium is reached, the valve 27 is closed. ,
The valves 15 and 19 are opened, and the compressor 21 is driven to recover the cooling gas via the gas recovery system 25. In this case, the recovered gas is recovered in the storage tank 12 while containing the impurities. When the gas in the vacuum heating furnace 1 is to be further recovered, a side pipe in which a vacuum pump 33 is disposed on the suction port side of the compressor 21 of the gas recovery system 25 as in the first embodiment. 32 may be provided, and the vacuum pump 33 may cooperate with the compressor 21.

When the recovery of the cooling gas from the vacuum heating furnace 1 is completed,
The valve 15 is closed, the valves 40 and 41 are opened, and the storage tank 1 is opened by the compressor 21.
The gas containing impurities collected in 2 is circulated from the recovered gas purification system 43 to the storage tank 12 via the gas recovery system 25. By this circulation, impurities in the gas are sequentially removed by the catalyst tube 23 and the adsorption tube 24, and the gas in the storage tank 12 is purified to high purity. When the desired purity is reached, the valves 40, 41, 19, 22, and 1
8, The valve 21 is closed and the compressor 21 is stopped. Thus, high-purity gas containing no impurities is stored in the storage tank 12 as a cooling gas.

When a plurality of catalyst cylinders 23 and adsorption cylinders 24 are provided in the same manner as in the first embodiment and the use and regeneration steps are alternately used, a continuous long-term operation can be advantageously performed.

As described above, in the second embodiment, the impurities contained in the gas used for cooling at the same time as the recovery cannot be removed and the recovery cannot be performed as in the first embodiment, but after the recovery, the recovered gas purification system 43, Since the gas can be purified by repeatedly circulating through the gas recovery system 25 and the storage tank 12, a gas purified to a higher purity than in the first embodiment can be obtained and collected and stored in the storage tank 12. As a result, it can be used extremely effectively for cooling the vacuum heating furnace 1 without contaminating the treated metal.

The number of valves in each of the above embodiments can be reduced by using a three-way valve or the like. As the cooling gas, various gases can be used as described above. In particular, by using helium as the cooling gas, a cooling rate superior to that of nitrogen can be obtained, and there is a danger of explosion such as hydrogen. Since there is no gas, it can be used in a pressurized state with peace of mind, and it is possible to obtain the effect of improving the cooling rate, shortening the cooling time, improving the quenching hardness, and the like, which are higher than other gases.

[Effects of the Invention] As described above, according to the present invention,
A gas supply system connecting a vacuum heating furnace and a storage tank storing a cooling gas was provided with a compressor and a gas purifying means arranged with a discharge port opened in a direction opposite to a gas flow of the gas supply system. Connect both ends of the gas recovery system, connect one end of the supply gas pressurization system to the discharge port side of the compressor of the gas recovery system,
The other end is connected to the vacuum heating furnace side from the vacuum heating furnace side branch of the gas recovery system of the gas supply system, and according to claim 2, the gas supply system, the gas recovery system and the supply gas pressurization of claim 1 In addition to the connection of the system, a recovery gas purification system provided with gas purification means is connected to the storage tank and the suction port side of the compressor of the gas recovery system. Since the operation can be performed by one compressor, there are many advantages such as simplification of the apparatus, low cost of the apparatus, easy operation and reduction of the operation cost.

Further, according to the present invention, since the gas recovery system is connected to a completely separate gas supply system from the vacuum exhaust system attached to the vacuum heating furnace, most of the impurity components generated in the furnace can be exhausted from the vacuum exhaust system, In the invention of claim 1, since the contamination with the recovered gas is small, and the impurity components mixed into the recovered gas can be removed by the gas purification means simultaneously with the recovery, the operation is simple and immediately after the recovery. The recovered gas can be used for cooling, which is extremely convenient in operation. Further, in the invention of claim 2, since the gas to be purified can be repeatedly passed through the gas purification means so as to be circulated to the recovery gas purification system, the removal of impurities is further promoted and the purity is extremely high. Purified gas can be recovered. As a result, denaturation such as oxidation of the metal when used for cooling the subsequently heat-treated metal is prevented, and the effect peculiar to the gas is exerted.

In addition, the present invention can recover gas after use for cooling and reuse it for cooling repeatedly, so that particularly expensive gas such as helium or argon can be used for cooling in heat treatment of metal. It can be used as
As a result, the quality of the heat-treated metal can be improved by using these gases. Moreover, the cooling process can be performed at low cost.

[Brief description of the drawings]

FIG. 1 is a system diagram illustrating a first embodiment of the present invention, and FIG. 2 is a system diagram illustrating a second embodiment. DESCRIPTION OF SYMBOLS 1 ... Vacuum heating furnace, 12 ... Storage tank, 17 ... Gas supply system, 21 ... Compressor, 23 ... Catalyst cylinder, 24 ... Adsorption cylinder, 25 ... Gas recovery system, 28
… Supply gas pressurization system, 43… Recovery gas purification system

Continuation of the front page (72) Inventor Yasuo Hinata 5-33-10 Kugahara, Ota-ku, Tokyo Inside Uekigas Science Co., Ltd. (56) References JP-A-63-310915 (JP, A) JP-A-57-41318 (JP, A) JP-A-61-73825 (JP, A) JP-A-56-5998 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) C21D 1 / 00,1 / 773 B22F 3/10 F27B 5 / 04,9 / 04,14 / 04 F27D 7 / 06,15 / 02

Claims (2)

(57) [Claims] An apparatus for supplying a cooling gas to a vacuum heating furnace provided with a heater for heating the inside of the furnace and a vacuum exhaust system having an exhaust means for evacuating the inside of the furnace, wherein the vacuum heating A gas supply system consisting of a pipe connecting a furnace and a storage tank storing a cooling gas, and a pipe connected at both ends to a pipe of the gas supply system, a discharge port having a gas flow of the gas supply system. A gas recovery system provided with a compressor arranged to be opened in the opposite direction, one end of the gas recovery system having a discharge port side pipeline of the compressor, and the other end of the gas supply system pipeline. A supply gas pressurization system connected to a vacuum heating path side from a vacuum heating furnace side branch of the recovery system, and gas purification means such as a catalyst tube and an adsorption tube are provided in a line of the gas recovery system. A gas supply device for cooling a vacuum heating furnace. 2. An apparatus for supplying a cooling gas to a vacuum heating furnace provided with a heater for heating the inside of the furnace and an evacuation system having an evacuation unit for evacuating the inside of the furnace, wherein the vacuum heating A gas supply system consisting of a pipe connecting a furnace and a storage tank storing a cooling gas, and a pipe connected at both ends to a pipe of the gas supply system, a discharge port having a gas flow of the gas supply system. A gas recovery system provided with a compressor arranged to be opened in the opposite direction, one end of the gas recovery system having a discharge port side pipeline of the compressor, and the other end of the gas supply system pipeline. A catalyst tube is connected to a pipe connecting the supply gas pressurization system connected to the vacuum heating furnace side from the vacuum heating furnace side branch of the recovery system, and the suction port side of the compressor arranged in the storage tank and the gas recovery system. Gas recovery system equipped with gas purification means, Cooling gas supply device of a vacuum heating furnace, characterized in that it comprises.