JP3230921U - Industrial furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrial furnace capable of accurately measuring a temperature. An industrial furnace has a container 12, a heat insulating body 16 in which an object to be processed is housed, a heater, one end and the other end, and one end is arranged in an internal space 18 of the heat insulating body 16 and the other end. Is formed on a cylinder 68 arranged outside the container 12 and one end of the cylinder 68, a measuring unit 70 for sealing one end of the cylinder 68, and a view arranged on the other end of the cylinder 68. It includes a port 72, a radiation thermometer 74 that measures the temperature of the measuring unit 70 via the view port 72, and a control device that inputs the temperature measured by the radiation thermometer 74 and controls the temperature of the heater. [Selection diagram] Fig. 2

Description

The present invention relates to an industrial furnace.

Conventionally, an object to be treated made of metal, magnetic material, ceramics or the like has been heat-treated in an industrial furnace. For example, the industrial furnace disclosed in Patent Document 1 below includes a heating chamber, a heater, and a muffle plate. A heater and a muffle plate are installed in the heating chamber. A muffle plate forms a storage area for the object to be treated.

The object to be processed is stored in the storage area. When an electric current is passed through the heater, the heater generates heat. The heat of the heater is transferred to the object to be processed via the muffle plate. The object to be treated is degreased, and then a predetermined treatment such as sintering is performed. In order to perform degreasing accurately, the temperature of the object to be treated or the temperature inside the heating chamber is measured and the heater is controlled.

International publication number WO2016 / 00600

If the temperature of the object to be processed or the temperature inside the heating chamber is not accurately measured, the object to be processed may become defective. It is required to accurately measure the temperature of the object to be processed or the temperature inside the heating chamber.

Therefore, an object of the present invention is to provide an industrial furnace capable of accurately measuring the temperature.

In order to solve the above problems, the industrial furnace according to the present invention has the following configuration.

The industrial furnace of the present invention has a container, a heat insulating body arranged in the internal space of the container and accommodating an object to be processed, a heater arranged in the internal space of the heat insulating body, and one end and the other end. A cylinder whose one end is arranged in the internal space of the heat insulating body and whose other end is arranged outside the container, and a measuring unit which is formed at one end of the cylinder and seals one end of the cylinder. A view port arranged at the other end of the cylinder, a radiation thermometer for measuring the temperature of the measuring unit via the view port, and a temperature measured by the radiation thermometer are input to control the temperature of the heater. It is equipped with a control device.

According to the present invention, one end of the tubular body is sealed by a measuring portion, so that the discharged material discharged from the object to be treated is difficult to enter into the tubular body. The cylinder and viewport are not easily contaminated by the emissions emitted from the object to be treated, making it easy to measure the temperature accurately with a radiation thermometer. Since the position of the measuring unit is fixed, the temperature can be measured under the same conditions for all objects to be processed. It is easy to process the object to be processed under the same conditions.

It is a drawing which shows the structure of an industrial furnace. It is a drawing which shows the structure of the temperature measuring apparatus. It is a drawing which shows the structure for supplying electric power to a heater.

The industrial furnace of the present invention will be described with reference to the drawings. The means described in one embodiment may be designated by the same reference numerals in other embodiments and the description thereof may be omitted.

[Embodiment 1]
The industrial furnace 10 of the present application shown in FIG. 1 has a container-shaped container 12, a heat insulating body 16 arranged in the internal space 14 of the container 12, a heater 20 arranged in the internal space 18 of the heat insulating body 16, and a gas source 26. The first supply pipe 30, the pump 34, and the internal space 14 of the pump 34 and the container 12 or the internal space 18 of the heat insulating body 16 connecting the gas source 26 to the internal space 14 of the container 12 or the internal space 18 of the heat insulating body 16. The exhaust pipe 38 to be connected is provided.

The industrial furnace 10 is an apparatus for performing sintering, semi-sintering, firing, degreasing, degassing, brazing, metallizing, quenching, materialization treatment, tempering, annealing, aging heat treatment, and the like.

[container]
The container 12 includes a container body 42 and a container lid 44. The container body 42 has a cylindrical shape, and both ends thereof are open. The container lid 44 opens and closes the openings at both ends of the container body 42. When both ends of the container body 42 are closed by the container lid 44, the internal space 14 of the container 12 becomes an airtight space. The internal space 14 of the container 12 is pressurized when gas is supplied from the gas source 26, and is depressurized when the gas is exhausted by the pump 34.

The container 12 includes an inner wall 46 and an outer wall 48, and has a double structure. Coolant flows between the inner wall 46 and the outer wall 48. The industrial furnace 10 may include a pump (not shown) for supplying a cooling liquid between the inner wall 46 and the outer wall 48.

[Insulation]
The heat insulating body 16 is arranged in the internal space 14 of the container 12. The heat insulating body 16 includes a heat insulating body body 50 and a heat insulating body lid 52. The heat insulating body 50 has a tubular shape or a box shape, and both ends are open. The openings at both ends of the heat insulating body 50 are opened and closed by the heat insulating lid 52. An opening / closing device (not shown) for the heat insulating body lid 52 is provided in the internal space 14 of the container 12. The heat insulating body lid 52 can be opened and closed with the container lid 44 closed. The insulation 16 is made of a heat resistant material such as graphite felt or graphite foil.

[heater]
The heater 20 is arranged in the internal space 18 of the heat insulating body 16. As the heater 20, a rod heater made of graphite can be used, and other types of heaters may be used. The heater 20 has a linear shape, and the length direction of the heater 20 faces the length direction of the heat insulating body 16. Further, a plurality of heaters 20 are arranged in the internal space 18 of the heat insulating body 16. A circuit (FIG. 3) for supplying electric power to the heater 20 is provided. Electric power is supplied to the heater 20 from the circuit, and the heater 20 generates heat. The heat of the heater 20 is confined in the internal space 18 of the heat insulating body 16.

[Processed object]
The object to be processed 22 is arranged in the internal space 18 of the heat insulating body 16. If necessary, a shelf or a stand on which the object to be processed 22 is placed is provided. The material of the object to be treated 22 is a superhard metal, an iron-based metal, a non-ferrous metal, a magnetic material, ceramics, graphite, high-speed steel (high-speed steel), die steel, low alloy steel, or the like, and the metal includes an alloy. The object to be treated 22 is a powder, a granular material, or a solid having a predetermined shape.

[Gas source]
The gas source 26 stores, produces, or both stores nitrogen, argon, hydrogen, carbon monoxide, helium, methane, and the like. The gas source 26 and the internal space 14 of the container 12 or the internal space 18 of the heat insulating body 16 are connected by a first supply pipe 30. In FIG. 1, the first supply pipe 30 connects the gas source 26 and the internal space 14 of the container 12. A valve 58 is provided in the first supply pipe 30. The gas flow rate can be controlled by opening and closing the valve 58. Gas is introduced from the gas source 26 into the internal space 14 of the container 12 or the internal space 18 of the heat insulating body 16 via the first supply pipe 30. A plurality of gas sources 26 may be used to supply a plurality of types of gas to the internal space 14 of the container 12 or the internal space 18 of the heat insulating body 16. A plurality of first supply pipes 30 are provided so that a plurality of types of gas can be supplied. Since the heat insulating body 16 is not completely airtight, the gas can be introduced into the internal space 14 of the container 12 or the internal space 18 of the heat insulating body 16 by introducing the gas into the other.

[pump]
The pump 34 and the internal space 14 of the container 12 or the internal space 18 of the heat insulating body 16 are connected by an exhaust pipe 38. The exhaust pipe 38 is provided with a valve 64, and the exhaust can be controlled by opening and closing the valve 64. Since the heat insulating body 16 is not completely airtight, by exhausting the gas from one of the internal space 14 of the container 12 or the internal space 18 of the heat insulating body 16, the gas is also exhausted from the other.

[Temperature measuring device]
The present application includes a temperature measuring device 66 for measuring the temperature of the internal space 18 of the heat insulating body 16 (FIG. 2). The temperature measuring device 66 includes a cylinder 68, a measuring unit 70, a viewport 72, and a radiation thermometer 74.

[Cylinder]
The cylinder body 68 is a linear cylinder made of a heat-resistant material such as graphite. One end of the tubular body 68 is arranged in the internal space 18 of the heat insulating body 16, and the other end is arranged outside the container 12. The container 12 and the heat insulating body 16 are provided with through holes for the tubular body 68 to pass through.

The tubular body 68 enters the hole 76 formed in the heat insulating body 16 and is held by the inner wall 77 forming the hole 76. Further, a double pipe 82 composed of an inner pipe 78 and an outer pipe 80 is arranged on the outer periphery of the tubular body 68. The tubular body 68 is held on the inner surface of the inner tube 78. The double pipe 82 is attached to the container 12 from the outside of the container 12. The inner pipe 78 is attached to the inner wall 46, and the outer pipe 80 is attached to the outer wall 48. The inner pipe 78 and the outer pipe 80 are connected between the inner wall 46 and the outer wall 48. The coolant flowing between the inner wall 46 and the outer wall 48 also flows between the inner pipe 78 and the outer pipe 80. Even if the temperature of the packing or the like used in the temperature measuring device 66 rises, it can be cooled by the coolant.

The first jig 84 is attached to the vicinity of the other end of the tubular body 68, and the second jig 86 is attached to the first jig 84. A viewport 72 is attached to the second jig 86.

[Measurement unit]
The measuring unit 70 is provided at one end of the tubular body 68. The measuring unit 70 is a plate body that seals one end of the tubular body 68. The measuring unit 70 is made of a heat-resistant member such as graphite like the tubular body 68. By measuring the temperature of the measuring unit 70 with the radiation thermometer 74, the temperature of the internal space 18 of the heat insulating body 16 is measured.

[Viewport]
The viewport 72 is arranged at the other end of the cylinder 68. The viewport 72 is made of a material that can transmit at least infrared rays. For example, the viewport 72 is a plate made of glass, heat-resistant resin, or the like. The viewport 72 is attached to the second jig 86. An opening 90 is provided in the second jig 86 so that the temperature of the measuring unit 70 can be measured by the radiation thermometer 74 via the opening 90 and the viewport 72.

[Gas inlet]
A gas introduction port 92 is formed in the vicinity of the other end of the tubular body 68 and in the first jig 84. The gas introduction port 92 is a hole formed by passing the first jig 84 and the cylinder body 68 in a straight line. The gas contained in the cylinder 68 is the same as the gas contained in the internal space 14 of the container 12. The present application includes a second supply pipe 94 that guides the gas of the gas source 26 to the introduction port 92 (FIG. 1). The second supply pipe 94 is connected to the gas source 26 together with the first supply pipe 30. The second supply pipe 94 is provided with a valve 96 that opens and closes the second supply pipe 94. Further, the second supply pipe 94 may be provided with a regulator for reducing the gas flow rate and a needle valve for adjusting the gas flow rate. The inside of the cylinder 68 and the vicinity of the other end of the cylinder 68 become positive pressure due to the gas. It is possible to prevent the gas leaking from the gap between the cylinder body 68 and the inner pipe 78 from entering the cylinder body 68 or drifting in the vicinity of the viewport 72 and adhering to the viewport 72. The transparency of the viewport 72 can be maintained.

[Radiation thermometer]
The radiation thermometer 74 measures the temperature of the measuring unit 70 via the viewport 72. The radiation thermometer 74 measures the intensity of infrared rays emitted from the measuring unit 70 and converts the measured infrared intensity into temperature. Since the viewport 72 is made of a material that transmits at least infrared rays, the viewport 72 is not affected by the measurement of the radiation thermometer 74. The measuring unit 70 is made of a heat-resistant material such as graphite and is black.

[Thermocouple thermometer]
In addition to the radiation thermometer 74, the present application also includes a thermocouple thermometer 98 (FIG. 1). The measurement point of the thermocouple thermometer 98 is the internal space 18 of the heat insulating body 16. The temperature zones measured by the radiation thermometer 74 and the thermocouple thermometer 98 are different. The radiation thermometer 74 corresponds to a high temperature, and the thermocouple thermometer 98 corresponds to a low temperature. If it is a predetermined temperature, for example, about 1500 to 1600 ° C. or higher, the temperature is measured by the radiation thermometer 74, and if it is lower than the predetermined temperature, the temperature is measured by the thermocouple thermometer 98. The thermocouple thermometer 98 cannot measure a temperature higher than a predetermined temperature, and if the temperature becomes high, the thermocouple thermometer 98 may break down. Therefore, a power device such as an air cylinder may be attached to the thermocouple thermometer 98, and the thermocouple thermometer 98 may be pulled out from the internal space 18 of the heat insulating body 16 when the temperature becomes high.

The structure of the heat insulating body 16 is symmetrical with respect to the center in the horizontal direction. The measurement unit 70 and the measurement points of the thermocouple thermometer 98 are arranged at positions symmetrical with respect to the horizontal center of the heat insulating body 16. If the internal space 18 of the heat insulating body 16 is low temperature, it is measured by a thermocouple thermometer 98, and if it is high temperature, it is measured by a radiation thermometer 74.

[Control device]
The present application includes a control device 100 in which the temperature measured by the radiation thermometer 74 and the temperature measured by the thermocouple thermometer 98 are input (FIG. 3). The control device 100 controls the temperature of the heater 20 according to the input temperature. The control device 100 includes an arithmetic circuit such as a CPU (Central Processing Unit) or a PLC (Programmable Logic Controller). An analog-digital conversion circuit is provided between the radiation thermometer 74 and the control device 100 and between the thermocouple thermometer 98 and the control device 100, and the temperatures of the radiation thermometer 74 and the thermocouple thermometer 98 can be used by the control device 100. It may be converted as follows.

The power supply circuit 102 for supplying power to the heater 20 is as shown in FIG. The power supply circuit 102 supplies three-phase alternating current power to the heater 20. The three terminals of three-phase alternating current are R, S, and T. The power supply circuit 102 includes wirings 104 connected to the terminals R, S, and T, an ammeter 106 for measuring the current flowing through the wirings 104, a switch 108 for selecting the wiring to supply power, and a transformer 110 for power conversion. The switch 108 can use an element such as a thyristor.

The temperature measured by the radiation thermometer 74, the temperature measured by the thermocouple thermometer 98, and the current value measured by the ammeter 106 are input to the control device 100. The control device 100 controls the on / off of the switch 108 so that the temperature of the internal space 18 of the heat insulating body 16 becomes a predetermined temperature.

[Other]
A fan 112 is provided in the internal space 14 of the container 12. A motor 114 for rotating the fan 112 is attached to the container lid 44. The fan 112 rotates when the container lid 44 is closed and the heat insulating body lid 52 is opened. Gas circulates in the internal space 14 of the container 12 and the internal space 18 of the heat insulating body 16.

A guide 116 may be provided from the heat insulating body 50 to the fan 112. The guide 116 determines the direction of the circulating gas. The shape of the guide 116 is not limited as long as the direction of the gas is determined. Since the container 12 has a double structure and the cooling liquid flows inside the container 12, the circulating gas is cooled by the cooling liquid. A water-cooled heat exchanger 118 may be arranged between the fan 112 and the heat insulator 16, and the heat exchanger 118 may also cool the gas.

[Heat treatment]
Next, the heat treatment using the industrial furnace 10 of the present application will be described. The heat treatment to be described is an example, and is appropriately changed depending on the type of the object to be treated 22 and the treatment method.

(1) The object to be processed 22 is housed in the internal space 18 of the heat insulating body 16, and the heat insulating body lid 52 and the container lid 44 are closed.

(2) The pump 34 is driven to exhaust gas from the internal space 14 of the container 12 and the internal space 18 of the heat insulating body 16. At the same time as this exhaust, gas is supplied from the gas source 26 to the internal space 14 of the container 12 and the internal space 18 of the heat insulating body 16, and the spaces 14, 18 and 28 are filled with predetermined gas. By adjusting the gas supply amount and the exhaust amount, the internal space 14 of the container 12 and the internal space 18 of the heat insulating body 16 are set to a predetermined pressure.

(3) Electric power is supplied to the heater 20 to generate heat in the heater 20 to raise the temperature of the internal space 18 of the heat insulating body 16. The object to be treated 22 arranged in the internal space 18 of the heat insulating body 16 is heated.

(4) The current flowing through the heater 20 is increased to raise the temperature of the object to be processed 22. For example, the object to be treated 22 is heat-treated at about 1500 ° C. or higher. At this time, the binder is released as gas from the object to be processed 22.

(5) After the object to be processed 22 is heat-treated, the object to be processed 22 is cooled. Open the heat insulating body lid 52. The fan 112 is rotated to circulate the gas and cool the object 22 to be processed. When cooling, gas may be introduced from the gas source 26 into the internal space 14 of the container 12 and the internal space 18 of the heat insulating body 16. Further, a cooling liquid may be supplied between the inner wall 46 and the outer wall 48 of the container 12 to cool the container 12. By cooling the container 12, the gas touching the inner wall 46 of the container 12 is cooled. The gas circulated by the heat exchanger 118 may be cooled. As the gas is cooled, the object to be processed 22 comes into contact with the gas and is cooled.

When the object to be processed 22 is cooled, the container lid 44 and the heat insulating body lid 52 are opened, and the object to be processed 22 is taken out.

[Temperature control]
The temperature control of the internal space 18 of the heat insulating body 16 in the heat treatment will be described. The temperature of the internal space 18 of the heat insulating body 16 is measured by a radiation thermometer 74 or a thermocouple thermometer 98. If it is lower than the predetermined value, it is measured by the thermocouple thermometer 98, and if it is higher than the predetermined value, it is measured by the radiation thermometer 74. For example, the temperature is first measured with the thermocouple thermometer 98, and if it becomes higher than the predetermined value, the temperature is measured with the radiation thermometer 74. The measured temperature is input to the control device 100. The value of the current flowing through the wiring 104 is also input to the control device 100. The control device 100 controls the on / off of the switch 108 according to the temperature and the current value, and controls the current flowing through the heater 20. As a method of controlling the current flowing through the heater 20, a control method such as PID (Proportional-Integral-Differential) control can be mentioned. By controlling the current flowing through the heater 20, the temperature of the internal space 18 of the heat insulating body 16 becomes a set value. When the temperature of the internal space 18 of the heat insulating body 16 becomes a set value, the temperature of the object to be processed 22 becomes a desired value, and the object to be processed 22 is degreased or the like.

During the heat treatment of the object 22 to be processed, gas is supplied from the gas source 26 to the cylinder 68 via the second supply pipe 94. The gas pressure inside the cylinder 68 and near the other end of the cylinder 68 becomes a positive pressure. It becomes difficult for the gas released from the object to be processed 22 to reach the viewport 72 in the cylinder 68 and near the other end. The discharge from the object to be processed 22 is less likely to adhere to the cylinder 68 and the viewport 72. The measurement unit 70 can be accurately measured with the radiation thermometer 74. Since the position of the measuring unit 70 is fixed, there is no temperature error every time the object 22 to be treated is heat-treated.

[Embodiment 2]
The measurement points of the measuring unit 70 and the thermocouple thermometer 98 were arranged symmetrically with respect to the center of the internal space 18 of the heat insulating body 16, but the measuring unit 70 and the thermocouple thermometer 98 were placed at arbitrary locations. It may be placed in. The measurement points of the measuring unit 74 and the thermocouple thermometer 98 are determined in consideration of the structure of the heat insulating body 16 and the temperature symmetry.

[Embodiment 3]
Instead of the thermocouple thermometer 98, a radiation thermometer capable of measuring a low temperature may be provided. In that case, a radiation thermometer capable of measuring a low temperature may be used in the same configuration as the temperature measuring device 66 of FIG. Further, if one radiation thermometer 74 can measure the temperature of the entire area, the thermocouple thermometer 98 can be omitted.

(Paragraph 1) The industrial furnace according to one aspect includes a container, a heat insulating body arranged in the internal space of the container and accommodating an object to be processed, a heater arranged in the internal space of the heat insulating body, and one end. A cylinder having the other end, one end being arranged in the internal space of the heat insulating body, and the other end being formed on a cylinder arranged outside the container and one end of the cylinder, sealing one end of the cylinder. A measuring unit to be stopped, a view port arranged at the other end of the cylinder, a radiation thermometer for measuring the temperature of the measuring unit via the view port, and a temperature measured by the radiation thermometer are input. , A control device for controlling the temperature of the heater is provided.

According to the industrial furnace described in paragraph 1, since one end of the cylinder is closed by measurement, it is difficult for the discharge discharged from the object to be processed to enter between the other end of the cylinder and the viewport. .. The viewport is less likely to get dirty with emissions, making it easier to accurately measure temperature with a radiation thermometer. Since the measuring unit is fixed at one end of the cylinder, the place where the temperature is measured does not change for each object to be processed. The temperature of all objects to be treated can be measured under the same conditions.

(Item 2) A gas source, an introduction port formed near the other end of the cylinder and for introducing gas from the gas source into the inside of the cylinder, and a pipe connecting the gas source and the introduction port are provided. Be prepared.

According to the industrial furnace described in item 2, gas is supplied to the vicinity of the other end of the cylinder. The discharge from the object to be treated is less likely to adhere to the inside of the cylinder and the viewport.

(Item 3) A double pipe composed of an inner pipe and an outer pipe attached to the container is provided, and the cylinder is held on the inner surface of the inner pipe.

According to the industrial furnace described in item 3, even if a gap is formed between the cylinder and the inner pipe, it is possible to prevent the emission from adhering to the viewport due to the gas.

(Item 4) A thermocouple thermometer for measuring the temperature of the internal space of the heat insulating body is provided, and the temperature measured by the radiation thermometer or the temperature measured by the thermocouple thermometer is input to the control device. The control device controls the temperature of the heater.

According to the industrial furnace described in the fourth item, the temperature of the heater can be controlled while using the radiation thermometer and the thermocouple thermometer properly according to the temperature.

(Item 5) The measuring portion that seals one end of the tubular body and the measuring portion of the thermocouple thermometer are arranged at locations symmetrical with respect to the center of the internal space of the heat insulating body.

According to the industrial furnace described in the fifth item, the radiation thermometer and the thermocouple thermometer can measure the temperature under the same conditions by arranging the measuring unit and the measuring portion of the thermocouple thermometer at the same temperature position.

In addition, the present invention can be implemented in a mode in which various improvements, modifications, and changes are made based on the knowledge of those skilled in the art without departing from the gist thereof. Each of the described embodiments is not independent and can be appropriately combined and implemented based on the knowledge of those skilled in the art.

10: Industrial furnace 12: Container 14: Container internal space 16: Insulation body 18: Insulation body internal space 20: Heater 22: Object 26: Gas source 30, 94: Supply pipe 34: Pump 38: Exhaust pipe 42 : Container body 44: Container lid 46: Inner wall 48: Outer wall 50: Insulation body 52: Insulation body lid 58, 64, 96: Valve 66: Temperature measuring device 68: Tube 70: Measuring unit 72: Viewport 74: Radiation Thermometer 76: Hole formed in the heat insulating body 77: Inner wall forming the hole 78: Inner pipe 80: Outer pipe 82: Double pipe 84, 86: Jig 90: Opening 92: Gas inlet 98: Thermocouple Thermometer 100: Control device 102: Power supply circuit 104: Wiring 106: Current meter 108: Switch 110: Transformer

Claims (5)

With the container
A heat insulating body arranged in the internal space of the container and accommodating an object to be treated,
A heater arranged in the internal space of the heat insulating body and
A cylinder having one end and the other end, one end arranged in the internal space of the heat insulating body and the other end arranged outside the container.
A measuring unit formed at one end of the cylinder and sealing one end of the cylinder,
A viewport located at the other end of the cylinder,
A radiation thermometer that measures the temperature of the measuring unit via the viewport,
A control device that controls the temperature of the heater by inputting the temperature measured by the radiation thermometer,
Industrial furnace equipped with. Gas source and
An introduction port formed near the other end of the cylinder and for introducing gas from a gas source into the cylinder,
The pipe that connects the gas source and the inlet,
The industrial furnace according to claim 1. The industrial furnace according to claim 1 or 2, further comprising a double pipe composed of an inner pipe and an outer pipe attached to the container, and the cylinder body is held on the inner surface of the inner pipe. A thermocouple thermometer for measuring the temperature of the internal space of the heat insulating body is provided.
The industrial furnace according to any one of claims 1 to 3, wherein the temperature measured by a radiation thermometer or the temperature measured by a thermocouple thermometer is input to the control device, and the control device controls the temperature of the heater. The industrial furnace according to claim 4, wherein the measuring portion that seals one end of the cylinder and the measuring portion of the thermocouple thermometer are arranged symmetrically with respect to the center of the internal space of the heat insulating body.

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