Method for measuring volume flow rate of superheated steam, device for measuring volume flow rate of superheated steam and heat treatment apparatus

Abstract

To provide a method for measuring the volume flow rate of a superheated steam and a device for measuring the volume flow rate of a superheated steam which can measure the volume flow rate of a superheated steam continuously fed to a feed destination of the superheated steam.SOLUTION: An oxygen-containing gas with a known oxygen concentration C1 is fed to a superheated steam flow pipe 30. The volume flow rate Vg of the gas fed to the superheated steam flow pipe 30 is measured. A superheated steam is fed to the superheated steam flow pipe 30. The oxygen concentration C2 of a mixed gas of the gas fed to the superheated steam flow pipe 30 and flowing through the superheated steam flow pipe 30 and the superheated steam is measured. The volume flow rate Vw of the superheated steam fed to the superheated steam flow pipe 30 is calculated using an equation of Vw=Vg×C1 / C2-Vg based on the volume flow rate Vg of the gas and the oxygen concentration C2 of the mixed gas, to measure the volume flow rate Vw of the superheated steam.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for measuring the volumetric flow rate of superheated steam, an apparatus for measuring the volumetric flow rate of superheated steam, and a heat treatment apparatus equipped with the apparatus for measuring the volumetric flow rate of superheated steam.

Background Art

[0002] It is known to supply superheated steam to a heat treatment chamber for heat-treating an object to be treated, and heat the object to be treated in the heat treatment chamber to perform heat treatment on the object to be treated (see, for example, Patent Document 1). In Patent Document 1, there is disclosed a steam reflow apparatus 1 that heats an object to be treated carried into a heating furnace 2 with superheated steam continuously supplied into the heating furnace 2 to perform heat treatment on the object to be treated. Only the temperature of the superheated steam continuously supplied to the heating furnace 2 is measured by a temperature sensor 4.

[0003] When performing heat treatment on an object to be treated with superheated steam, depending on the type of heat treatment, it may be required to more accurately grasp the state of the atmosphere in the heat treatment chamber where the heat treatment of the object to be treated is performed. In this case, it is desirable to be able to measure the volumetric flow rate of the superheated steam continuously supplied into the heat treatment chamber. However, in the steam reflow apparatus 1 disclosed in Patent Document 1, only the temperature of the superheated steam supplied to the heating furnace 2 can be measured, and the volumetric flow rate of the superheated steam cannot be measured.

[0004] As a method for measuring the amount of steam, the method disclosed in Patent Document 2 is known. In the measurement method disclosed in Patent Document 2, a gas with a known amount of steam is mixed with a high-temperature gas to be measured, and the amount of steam in the mixed gas is made sufficiently less than that in the gas to be measured. The temperature of the mixed gas is lowered to a temperature at which the humidity can be measured with a hygrometer such as a dry-wet bulb hygrometer or an electric resistance hygrometer, and based on the measurement result with the hygrometer, the amount of steam in the mixed gas is obtained. Then, the mixing ratio between the gas to be measured and the gas with a known amount of steam is obtained, and based on the obtained mixing ratio and the measured amount of steam in the mixed gas, the amount of steam in the gas to be measured is obtained.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the steam reflow apparatus 1 disclosed in Patent Document 1, only the temperature of the superheated steam supplied to the heating furnace 2, which is the supply destination of the superheated steam, can be measured, and the volume flow rate of the superheated steam cannot be measured. Further, in the measurement method disclosed in Patent Document 2, the gas to be measured is mixed with a gas having a known water vapor amount to lower the temperature, and then the water vapor amount of the mixed gas is obtained using a hygrometer, and based on this and the mixing ratio of the mixed gas, the water vapor amount of the gas to be measured is measured. Therefore, the volume flow rate of the superheated steam continuously supplied to the supply destination of the superheated steam cannot be measured.

[0007] An object of the present invention is to provide a method for measuring the volume flow rate of superheated steam that can measure the volume flow rate of superheated steam continuously supplied to the supply destination of the superheated steam, a measuring device for the volume flow rate of superheated steam, and a heat treatment device equipped with the measuring device.

Means for Solving the Problems

[0008] (1) In order to solve the above problems, the method for measuring the volumetric flow rate of superheated steam according to the present invention includes: a gas supply step of supplying a gas containing oxygen and having a known oxygen concentration C1 to a superheated steam flow pipe; a gas flow rate measurement step of measuring the volumetric flow rate Vg of the gas supplied to the superheated steam flow pipe; a superheated steam supply step of supplying superheated steam to the superheated steam flow pipe; an oxygen concentration measurement step of measuring the oxygen concentration C2 of a mixed gas of the gas and the superheated steam that is supplied to the superheated steam flow pipe and flows through the superheated steam flow pipe; and a superheated steam volumetric flow rate measurement step of measuring the volumetric flow rate Vw of the superheated steam supplied to the superheated steam flow pipe by calculating the volumetric flow rate Vw using the following formula (1) based on the volumetric flow rate Vg measured in the gas flow rate measurement step and the oxygen concentration C2 measured in the oxygen concentration measurement step. Vw = Vg × C1 / C2 - Vg ···· (Formula (1))

[0009] (2) In the above measurement method, the gas is air.

[0010] (3) In the above measurement method, the superheated steam flow pipe is heated by a heater.

[0011] (4) In order to solve the above problems, the apparatus for measuring the volumetric flow rate of superheated steam according to the present invention includes: a superheated steam flow pipe to which a gas containing oxygen and having a known oxygen concentration C1 and superheated steam are supplied; a gas flow rate measurement unit that measures the volumetric flow rate Vg of the gas supplied to the superheated steam flow pipe; an oxygen concentration measurement unit that measures the oxygen concentration C2 of a mixed gas of the gas and the superheated steam that is supplied to the superheated steam flow pipe and flows through the superheated steam flow pipe; and a superheated steam volumetric flow rate measurement unit that measures the volumetric flow rate Vw of the superheated steam supplied to the superheated steam flow pipe by calculating the volumetric flow rate Vw using the following formula (1) based on the volumetric flow rate Vg measured by the gas flow rate measurement unit and the oxygen concentration C2 measured by the oxygen concentration measurement unit. Vw = Vg × C1 / C2 - Vg ···· (Formula (1))

[0012] (5) In the measurement device, the gas is air.

[0013] (6) In the measurement device, the superheated steam flow pipe is heated by a heater.

[0014] (7) To solve the above problems, a heat treatment device of the present invention is a heat treatment device that heats an object to be treated with superheated steam to perform heat treatment on the object to be treated, and includes a heat treatment chamber in which the heat treatment of the object to be treated is performed, and a measurement device for the volume flow rate of superheated steam according to any one of claims 4 to 6. The heat treatment chamber is introduced with superheated steam supplied through the superheated steam flow pipe.

Advantages of the Invention

[0015] According to the present invention, the volume flow rate of superheated steam continuously supplied to the supply destination of superheated steam can be measured.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention can be widely applied to various applications as a method for measuring the volumetric flow rate of superheated steam, a device for measuring the volumetric flow rate of superheated steam, and a heat treatment device equipped with the device for measuring the volumetric flow rate of superheated steam. In the following description, first, the heat treatment device and the device for measuring the volumetric flow rate of superheated steam according to the embodiment of the present invention will be described, and then the method for measuring the volumetric flow rate of superheated steam according to the embodiment of the present invention will be described.

[0018] [Heat treatment device] FIG. 1 is a diagram schematically showing a heat treatment device 1 according to an embodiment of the present invention. The heat treatment device 1 is configured as a device that heats a workpiece 100 made of, for example, ceramic or metal with superheated steam to perform heat treatment on the workpiece 100. That is, the heat treatment device 1 is configured as a device that heats a workpiece 100 made of ceramic or metal in an atmosphere composed of superheated steam to perform heat treatment on the workpiece 100. Examples of the ceramic workpiece 100 include ceramic electronic components such as multilayer ceramic capacitors. Note that superheated steam is steam heated to a temperature higher than the boiling point and is dry steam at a temperature higher than the boiling point.

[0019] The heat treatment device 1 includes a heat treatment chamber 11 provided with an inlet 25 into which the workpiece 100 is carried and an outlet 26 from which the workpiece 100 is carried out. In the heat treatment device 1, in the heat treatment chamber 11, the workpiece 100 is heated in an atmosphere composed of superheated steam while being conveyed from the inlet 25 toward the outlet 26, and heat treatment of the workpiece 100 is performed. Examples of the heat treatment performed on the workpiece 100 in the heat treatment device 1 include degreasing treatment and sintering treatment.

[0020] When degreasing treatment is performed in the heat treatment apparatus 1, the workpiece 100 that has been machined or the like in the treatment process before the treatment in the heat treatment apparatus 1 is carried into the heat treatment apparatus 1. Then, in the heat treatment apparatus 1, the workpiece 100 is heated by an atmosphere of superheated steam, so that the oil and fat adhering to the workpiece 100 are hydrolyzed and removed. When sintering treatment is performed in the heat treatment apparatus 1, the workpiece 100 configured as a sintered body that is bonded with a binder containing a resin component and sintered by heat treatment is carried into the heat treatment apparatus 1. Then, in the heat treatment apparatus 1, the workpiece 100 is heated by an atmosphere of superheated steam, so that the binder is hydrolyzed and removed, and further, the workpiece 100 from which the binder has been removed is sintered.

[0021] In the heat treatment apparatus 1, the workpiece 100 is carried into the heat treatment chamber 11 and heated by an atmosphere composed of superheated steam while being conveyed in the heat treatment chamber 11. Thereby, heat treatment of the workpiece 100 is performed. Then, the workpiece 100 for which the heat treatment in the heat treatment chamber 11 has ended is carried out of the heat treatment chamber 11. Further, the workpiece 100 is continuously conveyed to the heat treatment chamber 11, heat treatment is performed while being continuously conveyed in the heat treatment chamber 11, and is continuously carried out of the heat treatment chamber 11.

[0022] Note that when the object to be processed 100 is carried into the heat treatment chamber 11, for example, it is carried in while being placed in a case 100a formed in a thin box shape. A plurality of objects to be processed 100 are stored in the case 100a in a state of being spread out at substantially equal intervals. Then, the object to be processed 100 is carried into the heat treatment chamber 11 while being placed in the case 100a. Note that the case 100a for storing a plurality of objects to be processed 100 is provided with, for example, a large number of holes formed on the peripheral side surfaces and the bottom surface, and an opening formed on the upper surface, so that the surrounding gas can pass through with almost no resistance. Thereby, the atmosphere in the heat treatment chamber 11 composed of superheated steam is configured to flow through the case 100a. Note that the case 100a may have a structure that allows the atmosphere in the heat treatment chamber 11 to flow through the case 100a with almost no resistance, and may be, for example, in a form formed of a net-like member.

[0023] The heat treatment apparatus 1 is configured to include a heat treatment chamber 11, a heating mechanism 12, an atmosphere gas supply unit 13, a superheated steam generator 14, an air supply source 15, an atmosphere discharge unit 16, an atmosphere separation gas supply unit 17, a gas curtain unit 18, a measuring device 10 for the volume flow rate of superheated steam, and the like.

[0024] The heat treatment chamber 11 has a tunnel-shaped outer shape that linearly extends in a cylindrical shape, and constitutes a chamber in which the object to be processed 100 is conveyed and the heat treatment of the object to be processed 100 is performed. The inside of the heat treatment chamber 11 becomes a processing space for performing the heat treatment of the object to be processed 100. The conveying direction of the object to be processed 100, that is, the direction in which the object to be processed 100 is conveyed in the heat treatment chamber 11, is a direction parallel to the longitudinal direction in which the heat treatment chamber 11 extends in a cylindrical shape. In FIG. 1, the conveying direction of the object to be processed 100 is indicated by a dashed-dotted arrow X1, and hereinafter, it is referred to as the conveying direction X1.

[0025] FIG. 2 is a schematic cross-sectional view of a part of the heat treatment apparatus 1, showing a state as viewed from the position of the arrow along the line A-A in FIG. 1. FIG. 3 is a schematic cross-sectional view of a part of the heat treatment apparatus 1, showing a state as viewed from the position of the arrow along the line B-B in FIG. 1. Referring to FIGS. 1 to 3, the heat treatment chamber 11 has a pair of side walls (11a, 11b), a ceiling wall 11c, and a bottom wall 11d. The pair of side walls (11a, 11b), the ceiling wall 11c, and the bottom wall 11d of the heat treatment chamber 11 are formed of steel plate-like members. The heat treatment chamber 11 is configured such that heat from the heating mechanism 12 described later for heating the heat treatment chamber 11 from the outside is easily conducted because it is formed of a steel plate-like member. The pair of side walls (11a, 11b) are arranged in parallel and are provided as wall portions extending along the vertical direction and the conveyance direction X1. The ceiling wall 11c is provided as a wall portion partitioning the ceiling portion of the upper part of the heat treatment chamber 11 and is provided so as to integrally connect the upper end portions of the pair of side walls (11a, 11b). Further, the ceiling wall 11c is formed so as to extend in an arch shape in a cross section perpendicular to the conveyance direction X1. The bottom wall 11d is provided as a wall portion partitioning the bottom portion of the heat treatment chamber 11 and is provided so as to integrally connect the lower end portions of the pair of side walls (11a, 11b).

[0026] The inlet 25 of the heat treatment chamber 11 is provided as an opening through which the object to be processed 100 is carried into the heat treatment chamber 11. The inlet 25 is provided as an opening at one end in the direction parallel to the conveyance direction X1 in the heat treatment chamber 11 and opens at the upstream end in the conveyance direction X1 in the heat treatment chamber 11. The inlet 25 is open to the outside of the heat treatment chamber 11, has no door, and is always open to the outside. Note that the object to be processed 100 is carried into the heat treatment chamber 11 through the inlet 25 while being stored in the case 100a.

[0027] The outlet 26 of the heat treatment chamber 11 is provided as an opening through which the workpiece 100 in the heat treatment chamber 11 is carried out. The outlet 26 is provided as an opening at the end opposite to the end on the inlet 25 side in the direction parallel to the conveying direction X1 in the heat treatment chamber 11, and opens at the downstream end in the conveying direction X1 in the heat treatment chamber 11. The outlet 26 is open to the outside of the heat treatment chamber 11, and no door is provided and it is always open to the outside. Incidentally, the workpiece 100 is carried out from the outlet 26 to the outside of the heat treatment chamber 11 in a state of being stored in the case 100a.

[0028] Inside the heat treatment chamber 11, the workpiece 100 is heated by superheated steam continuously supplied from the atmosphere gas supply unit 13 described later, and the heat treatment chamber 11 is heated by the heating mechanism 12 described later that heats the heat treatment chamber 11 from the outside, so that the workpiece 100 is also heated by the atmosphere inside the heat treatment chamber 11 heated through the heat treatment chamber 11. The atmosphere inside the heat treatment chamber 11 is composed of superheated steam supplied from the atmosphere gas supply unit 13 into the heat treatment chamber 11.

[0029] In addition, a conveying mechanism 20 is provided in the heat treatment chamber 11. The conveying mechanism 20 is provided as a mechanism for conveying the workpiece 100 inside the heat treatment chamber 11. In this embodiment, the conveying mechanism 20 is configured to convey the workpiece 100 together with the case 100a, that is, to convey the workpiece 100 in a state of being stored in the case 100a. The conveying mechanism 20 is arranged in the lower region inside the heat treatment chamber 11 and is arranged along the conveying direction X1 parallel to the wall surface of the bottom wall 11d above the bottom wall 11d. The conveying mechanism 20 is configured, for example, as a mechanism for conveying the workpiece 100 by a circulating endless mesh belt 21. And the conveying mechanism 20 is configured to convey the workpiece 100 stored in the case 100a arranged on the upper surface of the mesh belt 21 together with the case 100a when the mesh belt 21 circulates.

[0030] The endless mesh belt 21 has, for example, a structure in which roller chains are provided at both edge portions in the width direction thereof, and is driven by a plurality of drive shafts 22 provided with sprockets meshing with the roller chains, and is configured to circulate. The plurality of drive shafts 22 are installed so as to rotate around their respective axial centers while being inserted inside the mesh belt 21. The plurality of drive shafts 22 are arranged so as to extend parallel to each other and so as to extend along a direction perpendicular to the pair of side walls (11a, 11b). Further, each drive shaft 22 is rotatably supported with respect to the pair of side walls (11a, 11b). Further, a pair of sprockets (22a, 22a) arranged apart from each other in the axial direction are provided on each drive shaft 22, and each sprocket 22a meshes with each roller chain at both edge portions of the mesh belt 21. Further, at least one of the plurality of drive shafts 22 is configured to be rotationally driven by an electric motor (not shown). When the drive shaft 22 is rotationally driven by the electric motor, the rotational drive of the drive shaft 22 is transmitted to the mesh belt 21 through the meshing between the sprocket 22a and the roller chain. Then, the circulating operation of the mesh belt 21 rotatably supported by the plurality of drive shafts 22 is performed. When the mesh belt 21 performs the circulating operation, the object to be processed 100 arranged on the upper surface of the mesh belt 21 while being housed in the case 100a is conveyed.

[0031] Referring to FIG. 1, the heating mechanism 12 is provided as a mechanism for heating the heat treatment chamber 11 from the outside, and a plurality of heating mechanisms 12 are provided. The plurality of heating mechanisms 12 are arranged in series along the longitudinal direction of the heat treatment chamber 11 (that is, along the conveyance direction X1). In FIGS. 2 and 3, the illustration of the heating mechanism 12 is omitted. Each heating mechanism 12 includes a heating element (not shown) arranged around the heat treatment chamber 11 and a heat insulating member (not shown) arranged outside the heating element arranged around the heat treatment chamber 11 so as to cover the periphery of the heat treatment chamber 11 and the heating element. The heating element is arranged to heat a pair of side walls (11a, 11b), a ceiling wall 11c, and a bottom wall 11d in the heat treatment chamber 11 from the outside. The heating element includes, for example, a heating element that converts electrical energy supplied from a power source (not shown) into heat energy, and is configured to generate heat when the heating element is energized. When the heating element of the heating mechanism 12 operates and generates heat, a pair of side walls (11a, 11b), a ceiling wall 11c, and a bottom wall 11d of the heat treatment chamber 11 are heated by the heat from the heating element of the heating mechanism 12. Thereby, the atmosphere in the heat treatment chamber 11 is heated. Then, the workpiece 100 conveyed through the heat treatment chamber 11 is heated by the superheated steam supplied into the heat treatment chamber 11 and is also heated by the atmosphere in the heat treatment chamber 11 heated through the heat treatment chamber 11 by the heat from the heating mechanism 12.

[0032] Referring to FIGS. 1 and 2, the atmosphere gas supply unit 13 is provided inside the heat treatment chamber 11 and is provided as a mechanism for continuously supplying the atmosphere gas that constitutes the atmosphere in the heat treatment chamber 11 into the heat treatment chamber 11. In this embodiment, superheated steam is continuously supplied from the atmosphere gas supply unit 13 into the heat treatment chamber 11 as the atmosphere gas that constitutes the atmosphere in the heat treatment chamber 11. In the heat treatment apparatus 1 illustrated in this embodiment, the atmosphere gas supply unit 13 is provided at a substantially central portion in the conveyance direction X1 of the workpiece 100 in the heat treatment chamber 11. Note that the atmosphere gas supply unit 13 may be provided on the inlet 25 side or the outlet 26 side of the central portion in the conveyance direction X1 in the heat treatment chamber 11.

[0033] The atmosphere gas supply unit 13 includes a nozzle unit 23 that supplies superheated steam, which is supplied via a measuring device 10 for the volumetric flow rate of superheated steam described later, into the heat treatment chamber 11. The nozzle unit 23 is provided, for example, as a member that extends in a cylindrical shape and has both end portions in the axial direction of the cylinder closed. The nozzle unit 23 is arranged in the heat treatment chamber 11 in a state where its axial direction of the cylinder extends horizontally along the width direction of the heat treatment chamber 11. Incidentally, the width direction of the heat treatment chamber 11 is defined as a direction perpendicular to the longitudinal direction (i.e., the conveyance direction X1) of the horizontally extending heat treatment chamber 11 and the height direction (i.e., the vertical direction) of the heat treatment chamber 11.

[0034] Also, the nozzle unit 23 is connected to a superheated steam flow pipe 30 in the measuring device 10 for the volumetric flow rate of superheated steam, which will be described later, at a substantially central position in its axial direction of the cylinder. The superheated steam flow pipe 30, which will be described later, penetrates the ceiling wall 11c of the heat treatment chamber 11 and is connected to the nozzle unit 23 in the heat treatment chamber 11. The inside of the nozzle unit 23 and the inside of the superheated steam flow pipe 30 are in communication with each other, and the superheated steam supplied from the superheated steam flow pipe 30 is supplied into the inside of the nozzle unit 23. Further, the nozzle unit 23 is provided with a plurality of nozzle holes 23a that open toward the upstream side and the downstream side in the conveyance direction X1. Each nozzle hole 23a is provided, for example, as a through hole that opens in a circular shape. Incidentally, the opening shape of each nozzle hole 23a is not limited to a circular shape, and may be formed in various shapes such as a rectangular shape, a slit shape, and the like.

[0035] The plurality of nozzle holes 23a are provided on both sides of the nozzle portion 23 in the conveyance direction X1, and are formed so as to open toward the upstream side and the downstream side in the conveyance direction X1, respectively. Further, the plurality of nozzle holes 23a are arranged linearly along the cylindrical axis direction of the nozzle portion 23 on each of the upstream side and the downstream side in the conveyance direction X1, and are arranged, for example, at equal intervals. Since the cylindrical axis direction of the nozzle portion 23 is along the width direction of the heat treatment chamber 11, the plurality of nozzle holes 23a in the nozzle portion 23 are arranged along the width direction of the heat treatment chamber 11. The superheated steam supplied from the superheated steam flow pipe 30 to the nozzle portion 23 fills the nozzle portion 23 and further blows out to the outside from the plurality of nozzle holes 23a. By blowing out the superheated steam from the plurality of nozzle holes 23a, the superheated steam is supplied from the nozzle portion 23 into the heat treatment chamber 11. Since the above-described atmosphere gas supply unit 13 is provided in the heat treatment chamber 11, the heat treatment chamber 11 is configured such that the superheated steam supplied through the superheated steam flow pipe 30 in the superheated steam volume flow rate measuring device 10 described later is introduced.

[0036] Referring to FIGS. 1 and 3, the atmosphere discharge unit 16 is provided as a mechanism for discharging the atmosphere in the heat treatment chamber 11 to the outside of the heat treatment chamber 11. And the atmosphere discharge unit 16 is provided on the inlet 25 side and the outlet 26 side with respect to the atmosphere gas supply unit 13 in the heat treatment chamber 11, respectively. On the inlet 25 side of the heat treatment chamber 11, an inlet side atmosphere discharge unit 16a is provided as the atmosphere discharge unit 16. On the outlet 26 side of the heat treatment chamber 11, an outlet side atmosphere discharge unit 16b is provided as the atmosphere discharge unit 16. In the present embodiment, the inlet side atmosphere discharge unit 16a is disposed at a position corresponding to the heating mechanism 12 disposed on the most inlet 25 side among the plurality of heating mechanisms 12 arranged along the transport direction X1 in the heat treatment chamber 11. And the outlet side atmosphere discharge unit 16b is disposed at a position corresponding to the heating mechanism 12 disposed on the most outlet 26 side among the plurality of heating mechanisms 12 arranged along the transport direction X1 in the heat treatment chamber 11. Further, the inlet side atmosphere discharge unit 16a and the outlet side atmosphere discharge unit 16b are disposed in the regions on the inlet 25 side and the outlet 26 side in the heat treatment chamber 11, respectively, in the region on the ceiling wall 11c side, that is, in the upper half side region in the cross section perpendicular to the transport direction X1 of the heat treatment chamber 11.

[0037] The inlet side atmosphere discharge unit 16a and the outlet side atmosphere discharge unit 16b are similarly configured and are formed in a hollow box shape extending along the width direction of the heat treatment chamber 11. And each of the inlet side atmosphere discharge unit 16a and the outlet side atmosphere discharge unit 16b includes an upper wall 24a extending in an arch shape along the ceiling wall 11c in a cross section perpendicular to the transport direction X1, a lower wall 24b extending horizontally, and a pair of side walls extending along the cross section perpendicular to the transport direction X1. Thereby, the inner hollow region of each of the inlet side atmosphere discharge unit 16a and the outlet side atmosphere discharge unit 16b is formed as an arc-shaped dome-shaped hollow region surrounded by the upper wall 24a, the lower wall 24b, and the pair of side walls.

[0038] In addition, a plurality of through holes (not shown) for sucking the atmosphere in the heat treatment chamber 11 are provided in the lower walls 24b of the inlet-side atmosphere discharge portion 16a and the outlet-side atmosphere discharge portion 16b, respectively. The atmosphere in the heat treatment chamber 11 is sucked from each of the inlet-side atmosphere discharge portion 16a and the outlet-side atmosphere discharge portion 16b and discharged from the heat treatment chamber 11. Each of the inlet-side atmosphere discharge portion 16a and the outlet-side atmosphere discharge portion 16b is connected to an atmosphere discharge system (not shown) that sucks the atmosphere from the inlet-side atmosphere discharge portion 16a and the outlet-side atmosphere discharge portion 16b and discharges the atmosphere to the outside of the heat treatment chamber 11. The atmosphere discharge system includes a discharge pipe (not shown) and an ejector (not shown) connected to each of the inlet-side atmosphere discharge portion 16a and the outlet-side atmosphere discharge portion 16b. The ejector is provided as a mechanism that generates a negative pressure using high-pressure fluid to suck the atmosphere in the heat treatment chamber 11 from each of the inlet-side atmosphere discharge portion 16a and the outlet-side atmosphere discharge portion 16b through the discharge pipe, and further discharges the sucked atmosphere to the outside.

[0039] Referring to FIGS. 1 and 3, the atmosphere separation gas supply unit 17 is provided as a mechanism for supplying at least one of an inert gas and air into the heat treatment chamber 11 in order to separate the atmosphere in the regions on the inlet 25 side and the outlet 26 side in the heat treatment chamber 11. That is, the atmosphere separation gas supply unit 17 is provided as a mechanism for supplying an inert gas such as nitrogen gas into the heat treatment chamber 11, or as a mechanism for supplying air into the heat treatment chamber 11, or as a mechanism for supplying a mixed gas of an inert gas and air into the heat treatment chamber 11, in order to separate the atmosphere in the regions on the inlet 25 side and the outlet 26 side in the heat treatment chamber 11. In the heat treatment apparatus 1, an inlet side atmosphere separation gas supply unit 17a and an outlet side atmosphere separation gas supply unit 17b are provided as the atmosphere separation gas supply unit 17. The inlet side atmosphere separation gas supply unit 17a is provided further on the inlet 25 side than the inlet side atmosphere discharge unit 16a provided on the inlet 25 side with respect to the atmosphere gas supply unit 13 in the heat treatment chamber 11. The outlet side atmosphere separation gas supply unit 17b is provided actually on the outlet 26 side than the outlet side atmosphere discharge unit 16b provided on the outlet 26 side with respect to the atmosphere gas supply unit 13 in the heat treatment chamber 11.

[0040] The inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b are similarly configured. For example, they are provided as members that extend in a cylindrical shape and have both ends in the cylindrical axis direction closed. Each of the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b is arranged in the heat treatment chamber 11 in a state where its cylindrical axis direction extends horizontally along the width direction of the heat treatment chamber 11. Each of the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b is connected to a gas supply system (not shown) that supplies a gas as an inert gas or air at a substantially central position in its cylindrical axis direction. Gas is supplied from the gas supply system into each of the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b. Further, a plurality of nozzle holes (not shown) are provided in each of the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b. The plurality of nozzle holes are arranged linearly along the cylindrical axis direction in each of the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b, and are arranged, for example, at equal intervals. Also, all of the plurality of nozzle holes arranged along the cylindrical axis direction in each of the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b open downward. For this reason, an inert gas or air is blown downward from the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b.

[0041] With the above configuration, the gas supplied to the inlet-side atmosphere separation gas supply section 17a and the outlet-side atmosphere separation gas supply section 17b blows downward from a plurality of nozzle holes and is supplied into the heat treatment chamber 11. Then, when gas is supplied from the inlet-side atmosphere separation gas supply section 17a provided on the inlet 25 side rather than the inlet-side atmosphere discharge section 16a, the atmosphere in the heat treatment chamber 11 is separated between the inlet 25 and the inlet-side atmosphere discharge section 16a. Also, when gas is supplied from the outlet-side atmosphere separation gas supply section 17b provided on the outlet 26 side rather than the outlet-side atmosphere discharge section 16b, the atmosphere in the heat treatment chamber 11 is separated between the outlet 26 and the outlet-side atmosphere discharge section 16b.

[0042] Referring to FIG. 1, the gas curtain section 18 is provided as a mechanism for injecting an inert gas so as to form a region where the inert gas spreads in a curtain shape at the end on the inlet 25 side and the end on the outlet 26 side in the heat treatment chamber 11. At the end on the inlet 25 side of the heat treatment chamber 11, an inlet gas curtain section 18a is provided as the gas curtain section 18, and at the end on the outlet 26 side of the heat treatment chamber 11, an outlet gas curtain section 18b is provided as the gas curtain section 18.

[0043] The inlet gas curtain section 18a and the outlet gas curtain section 18b are each formed in a hollow box shape and have a gas supply box to which an inert gas from an inert gas supply source (not shown) is supplied. The gas supply box of the inlet gas curtain section 18a is installed at the end on the inlet 25 side in the heat treatment chamber 11, and the gas supply box of the outlet gas curtain section 18b is installed at the end on the outlet 26 side in the heat treatment chamber 11. A plurality of injection holes communicating with the inside of the heat treatment chamber 11 are provided in each of the gas supply boxes of the inlet gas curtain section 18a and the outlet gas curtain section 18b. The plurality of injection holes provided in each gas supply box are configured to inject the inert gas supplied from the inert gas supply source into the inside of the heat treatment chamber 11. Further, the plurality of injection holes of the gas supply boxes of the inlet gas curtain section 18a and the outlet gas curtain section 18b are configured to inject the inert gas so that the inert gas spreads in a curtain shape along the direction parallel to the opening surfaces of the inlet 25 and the outlet 26. By injecting the inert gas in a curtain shape from the inlet gas curtain section 18a and the outlet gas curtain section 18b at the ends on the inlet 25 side and the outlet 26 side of the heat treatment chamber 11, the atmosphere between the inner region and the outer region of the heat treatment chamber 11 is separated in the vicinity of the inlet 25 and the outlet 26 of the heat treatment chamber 11.

[0044] Referring to FIG. 1, the superheated steam generator 14 is provided as a mechanism for generating superheated steam to be supplied to the heat treatment chamber 11. The superheated steam generator 14 is configured to include a boiler and a superheater. The superheated steam generator 14 uses the boiler to heat and evaporate water to generate saturated steam at a temperature around the boiling point, and uses the superheater to further heat the saturated steam generated by the boiler to generate superheated steam. The superheated steam generated by the superheated steam generator 14 is continuously supplied to the measuring device 10 for the volumetric flow rate of superheated steam. The superheated steam supplied to the measuring device 10 for the volumetric flow rate of superheated steam passes through the superheated steam flow pipe 30 of the measuring device 10 for the volumetric flow rate of superheated steam, and is continuously supplied from the measuring device 10 for the volumetric flow rate of superheated steam to the heat treatment chamber 11. Note that the superheated steam generator 14 is electrically connected to a controller 34 described later, and the operation of the superheated steam generator 14 is configured to be controlled by the controller 34.

[0045] Referring to FIG. 1, the air supply source 15 is provided as a source for supplying air to the measuring device 10 for the volumetric flow rate of superheated steam, generates compressed air as the air to be supplied to the measuring device 10 for the volumetric flow rate of superheated steam, and is provided to supply the generated compressed air to the measuring device 10 for the volumetric flow rate of superheated steam. The air supply source 15 is configured to include, for example, a compressor for generating compressed air and a compressed air tank for storing the generated compressed air, and is configured to supply compressed air from the compressed air tank to the measuring device 10 for the volumetric flow rate of superheated steam. Note that the air supplied from the air supply source 15 is supplied to the superheated steam flow pipe 30 in the measuring device 10 for the volumetric flow rate of superheated steam. Also, the supply of air from the air supply source 15 to the superheated steam flow pipe 30 of the measuring device 10 for the volumetric flow rate of superheated steam is performed when the volumetric flow rate of superheated steam is measured by the measuring device 10 for the volumetric flow rate of superheated steam. Note that the air supply source 15 is electrically connected to a controller 34 described later, and the operation of the air supply source 15 is configured to be controlled by the controller 34.

[0046] FIG. 4 is a diagram showing a measuring device 10 for the volume flow rate of superheated steam according to an embodiment of the present invention. In the following description, the measuring device 10 for the volume flow rate of superheated steam is simply referred to as the measuring device 10. Referring to FIGS. 1 and 4, the measuring device 10 provided in the heat treatment device 1 is configured such that superheated steam is supplied from a superheated steam generator 14 and air, which is a gas containing oxygen and has a known oxygen concentration C1 (%) as a gas, is supplied from an air supply source 15. Further, the measuring device 10 measures the volume flow rate Vg of the air supplied from the air supply source 15, measures the oxygen concentration C2 (%) of the mixed gas of the supplied superheated steam and air, and measures the volume flow rate Vw of the supplied superheated steam based on the measured volume flow rate Vg and oxygen concentration C2. Then, the measuring device 10 is configured to introduce air and the superheated steam with the measured volume flow rate Vw into the heat treatment chamber 11.

[0047] Note that when measuring the volume flow rate Vw of superheated steam, the measuring device 10 is configured such that superheated steam is supplied from the superheated steam generator 14 and air, which is a gas containing oxygen and has a known oxygen concentration C1 (%) as a gas, is supplied from the air supply source 15. And when the heat treatment of the workpiece 100 is performed in the heat treatment device 1, the measuring device 10 is configured such that only the superheated steam with the measured volume flow rate Vw is supplied and the supply of air from the air supply source 15 is not performed. That is, when the heat treatment of the workpiece 100 is performed in the heat treatment device 1, only the superheated steam with the measured volume flow rate Vw is supplied from the superheated steam generator 14 to the measuring device 10, and the superheated steam passing through the measuring device 10 is continuously supplied to the heat treatment chamber 11. Hereinafter, the measuring device 10 for the volume flow rate of superheated steam will be described in more detail.

[0048] [Measuring Device for Volume Flow Rate of Superheated Steam] Referring to FIGS. 1 and 4, a measuring device 10 for the volumetric flow rate of superheated steam according to an embodiment of the present invention is provided in a heat treatment device 1. When measuring the volumetric flow rate Vw of superheated steam, the measuring device 10 is configured such that superheated steam is continuously supplied from a superheated steam generator 14, and air with an oxygen concentration C1 of 21% (which is known) is continuously supplied from an air supply source 15 in a compressed air state. Here, the oxygen concentration C1 is the volume concentration (%) of oxygen in the air and the volume fraction (%) of oxygen in the air. Further, the measuring device 10 measures the volumetric flow rate Vg of the air supplied from the air supply source 15 and measures the oxygen concentration C2 of the mixed gas of superheated steam and air, and is configured to measure the volumetric flow rate Vw of superheated steam in the mixed gas based on these measurement results. Here, the oxygen concentration C2 is the volume concentration (%) of oxygen in the mixed gas and the volume fraction (%) of oxygen in the mixed gas.

[0049] In this embodiment, when the volumetric flow rate Vw of superheated steam is measured by the measuring device 10, air is supplied to the measuring device 10 as a gas containing oxygen with a known oxygen concentration C1. However, the gas containing oxygen with a known oxygen concentration C1 is not limited to air. The gas containing oxygen supplied to the measuring device 10 may be any gas as long as the oxygen concentration C1 is known, and may be a gas other than air. For example, the gas containing oxygen supplied to the measuring device 10 may be an oxygen gas composed only of oxygen with a known oxygen concentration of 100%, or a gas in which oxygen and nitrogen are mixed to have a specific oxygen concentration.

[0050] The measuring device 10 includes a superheated steam flow pipe 30, a heater 31, a flow meter 32, an oxygen concentration meter 33, a controller 34, and the like.

[0051] Referring to FIGS. 1 and 4, the superheated steam flow pipe 30 is configured as a pipe through which a gas containing oxygen with a known oxygen concentration C1 and superheated steam are supplied, and a mixed gas of the supplied gas with a known oxygen concentration C1 and superheated steam flows. In this embodiment, air is supplied to the superheated steam flow pipe 30 as the gas containing oxygen with a known oxygen concentration C1. The oxygen concentration C1 of the air supplied to the superheated steam flow pipe 30 is known to be 21%. Note that when the measuring device 10 measures the volume flow rate Vw of the superheated steam, superheated steam and air with an oxygen concentration of 21% (a known gas) are supplied to the superheated steam flow pipe 30, and a mixed gas of superheated steam and air flows. On the other hand, when the heat treatment of the workpiece 100 is performed in the heat treatment device 1, only the superheated steam with the measured volume flow rate Vw is supplied to the superheated steam flow pipe 30, and no air is supplied. When the heat treatment of the workpiece 100 is performed in the heat treatment device 1, the measuring device 10 does not perform the measurement operation of the volume flow rate Vw of the superheated steam. Only the superheated steam is supplied to the superheated steam flow pipe 30, and the superheated steam supplied to the superheated steam flow pipe 30 passes through the superheated steam flow pipe 30 and is introduced into the heat treatment chamber 11.

[0052] The superheated steam flow pipe 30 is connected to the superheated steam generator 14 at its upstream end, and the superheated steam generated by the superheated steam generator 14 is continuously supplied to the superheated steam flow pipe 30. Further, the superheated steam flow pipe 30 is connected to the air supply source 15 via the air supply pipe 35. The air supplied from the air supply source 15 is continuously supplied to the superheated steam flow pipe 30 via the air supply pipe 35.

[0053] Note that an on-off valve 35a for switching the connection state between the air supply source 15 and the superheated steam flow pipe 30 is provided in the air supply pipe 35. The on-off valve 35a provided in the air supply pipe 35 is configured to open the flow path of the air supply pipe 35 leading from the air supply source 15 to the superheated steam flow pipe 30 and supply the air supplied from the air supply source 15 to the superheated steam flow pipe 30 when in the open state. And the on-off valve 35a is configured to close the flow path of the air supply pipe 35 and not supply the air from the air supply source 15 to the superheated steam flow pipe 30 when in the closed state. The operation of the on-off valve 35a is configured to be controlled by the controller 34. When the volume flow rate Vw of the superheated steam is measured by the measuring device 10, the controller 34 controls the on-off valve 35a to be in the open state. Therefore, when the volume flow rate Vw of the superheated steam is measured by the measuring device 10, the air supplied from the air supply source 15 is supplied to the superheated steam flow pipe 30 through the air supply pipe 35. Also, when the volume flow rate Vw of the superheated steam is not measured by the measuring device 10 and the heat treatment of the workpiece 100 is performed in the heat treatment apparatus 1, the controller 34 controls the on-off valve 35a to be in the closed state. Therefore, when the heat treatment of the workpiece 100 is performed in the heat treatment apparatus 1, the flow path of the air supply pipe 35 is closed, and the supply of air from the air supply source 15 to the superheated steam flow pipe 30 is not performed.

[0054] When the volume flow rate Vw of the superheated steam is measured by the measuring device 10 and the superheated steam supplied from the superheated steam generator 14 and the air supplied from the air supply source 15 are supplied to the superheated steam flow pipe 30, the supplied superheated steam and air are mixed in the superheated steam flow pipe 30 to form a mixed gas of superheated steam and air. The mixed gas of superheated steam and air flows downstream in the superheated steam flow pipe 30. A part of the mixed gas of superheated steam and air that has flowed downstream in the superheated steam flow pipe 30 is introduced into an oxygen concentration meter 33 described later connected to the superheated steam flow pipe 30. Also, the remaining mixed gas that has not flowed from the superheated steam flow pipe 30 to the oxygen concentration meter 33 flows further downstream in the superheated steam flow pipe 30 and is introduced into the heat treatment chamber 11.

[0055] Further, when the measurement of the volume flow rate Vw of superheated steam is not performed in the measuring device 10 and the heat treatment of the workpiece 100 is performed in the heat treatment device 1, only the superheated steam supplied from the superheated steam generator 14 is supplied to the superheated steam flow pipe 30 and flows downstream in the superheated steam flow pipe 30. When the heat treatment of the workpiece 100 is performed in the heat treatment device 1, an on-off valve 33d, which is provided in the oxygen concentration meter 33 and switches the connection state between the superheated steam flow pipe 30 and the oxygen concentration meter 33, is closed, and the superheated steam flowing downstream in the superheated steam flow pipe 30 is not introduced into the oxygen concentration meter 33 but is continuously supplied to the heat treatment chamber 11, which is the supply destination of the superheated steam. Note that the downstream end of the superheated steam flow pipe 30 is connected to the atmosphere gas supply unit 13 disposed in the heat treatment chamber 11. Thereby, when the heat treatment of the workpiece 100 is performed in the heat treatment device 1, superheated steam supplied through the superheated steam flow pipe 30 is introduced into the heat treatment chamber 11.

[0056] The superheated steam flow pipe 30 is provided, for example, as a metal pipe and is configured to be heated from the surroundings by the heater 31. FIG. 5 is a diagram schematically showing the superheated steam flow pipe 30 and the heater 31 in the measuring device 10. Referring to FIGS. 4 and 5, the heater 31 is provided on the superheated steam flow pipe 30 and is configured to heat the superheated steam flow pipe 30 to heat the mixed gas of superheated steam and air supplied to the superheated steam flow pipe 30 and flowing through the superheated steam flow pipe 30 when the volume flow rate Vw of the superheated steam in the measuring device 10 is measured. Alternatively, the heater 31 is configured to heat the superheated steam supplied from the superheated steam generator 14 and flowing through the superheated steam flow pipe 30 by heating the superheated steam flow pipe 30 when the heat treatment of the object to be treated 100 in the heat treatment device 1 is performed. In the present embodiment, the heater 31 is provided around the superheated steam flow pipe 30 and is configured to heat the superheated steam flow pipe 30 from the outside. The mixed gas of superheated steam and air supplied to the superheated steam flow pipe 30, or the superheated steam supplied to the superheated steam flow pipe 30, is heated by the superheated steam flow pipe 30 heated by the heater 31 while flowing through the superheated steam flow pipe 30, and the temperature drop when flowing through the superheated steam flow pipe 30 is suppressed.

[0057] Further, the heater 31 includes a heating element 36 disposed around the superheated steam flow pipe 30 so as to be spirally wound around the outer periphery of the superheated steam flow pipe 30, and a heat insulation case 37 surrounding the superheated steam flow pipe 30 and the heating element 36. The heating element 36 is provided to generate heat and output power when energized, and heat the superheated steam flow pipe 30 to heat the mixed gas of superheated steam and air or superheated steam flowing through the superheated steam flow pipe 30. The heating element 36 of the heater 31 is connected to a power source (not shown), and the power supplied to the heating element 36 of the heater 31 is configured to be controlled by the controller 34. By controlling the power supplied to the heater 31 by the controller 34, the temperature of the mixed gas or superheated steam flowing through the superheated steam flow pipe 30 while being heated by the heater 31 is controlled. The heat insulation case 37 is provided to surround the superheated steam flow pipe 30 and the heating element 36 and cover them, and is configured to keep warm the superheated steam flow pipe 30 heated by the heating element 36. The heat insulation case 37 may be filled with, for example, a heat insulating material.

[0058] Referring to FIGS. 1 and 4, the flow meter 32 is configured as a flow meter that measures the volume flow rate Vg of air supplied from the air supply source 15 to the superheated steam flow pipe 30 when the volume flow rate Vw of superheated steam is measured by the measuring device 10. The flow meter 32 constitutes the gas flow rate measuring unit of the present embodiment, and is configured to measure the volume flow rate Vg of air, which is a gas containing oxygen and has a known oxygen concentration C1 of 21%, supplied to the superheated steam flow pipe 30. The flow meter 32 is provided in the air supply pipe 35 that supplies air from the air supply source 15 to the superheated steam flow pipe 30, and measures the volume flow rate Vg of air supplied to the superheated steam flow pipe 30 through the air supply pipe 35. As the flow meter 32, various flow meters can be used, such as an ultrasonic flow meter, a differential pressure flow meter, and an area flow meter. Further, the flow meter 32 is electrically connected to the controller 34, and the measured value of the volume flow rate Vg of air measured by the flow meter 32 is transmitted to the controller 34.

[0059] Referring to FIGS. 1 and 4, when the measuring device 10 measures the volume flow rate Vw of superheated steam, the oxygen concentration meter 33 is configured as an oxygen concentration meter that measures the oxygen concentration C2 of the mixed gas of air and superheated steam flowing through the superheated steam flow pipe 30. The oxygen concentration meter 33 constitutes the oxygen concentration measuring unit of the present embodiment, and is configured to measure the oxygen concentration C2 of the mixed gas of air and superheated steam, which is a gas with a known oxygen concentration C1, supplied to the superheated steam flow pipe 30 and flowing through the superheated steam flow pipe 30. The oxygen concentration meter 33 is provided in the superheated steam flow pipe 30 on the downstream side of the superheated steam flow pipe 30, and is configured to measure the oxygen concentration C2 of the mixed gas of superheated steam and air flowing through the superheated steam flow pipe 30 in a substantially uniformly mixed state.

[0060] The oxygen concentration meter 33 is configured as, for example, a zirconia type oxygen concentration meter. The oxygen concentration meter 33 includes an introduction pipe 33a connected to the superheated steam flow pipe 30 through which the mixed gas flowing through the superheated steam flow pipe 30 is introduced, a concentration meter main body 33b having a chamber (not shown) into which the mixed gas is introduced from the introduction pipe 33a, a zirconia element (not shown) provided in the chamber into which the mixed gas is introduced, and a discharge pipe 33c for discharging the mixed gas introduced into the chamber of the concentration meter main body 33b to the outside of the chamber of the concentration meter main body 33b. The oxygen concentration meter 33 has electrodes provided at both ends of the zirconia element. By flowing the mixed gas at one end of the zirconia element and flowing air as a reference gas at the other end to generate an oxygen concentration difference at both ends of the zirconia element, and detecting the electromotive force generated between the electrodes at both ends of the zirconia element, the oxygen concentration C2 is measured. Further, the oxygen concentration meter 33 is electrically connected to the controller 34, and the measured value of the oxygen concentration C2 of the mixed gas of superheated steam and air measured by the oxygen concentration meter 33 is transmitted to the controller 34.

[0061] Note that the concentration meter main body 33b of the oxygen concentration meter 33 and the superheated steam flow pipe 30 are connected by an introduction pipe 33a. The mixed gas of superheated steam and air flowing through the superheated steam flow pipe 30 is introduced into the concentration meter main body 33b through the introduction pipe 33a. And an on-off valve 33d for switching the connection state between the superheated steam flow pipe 30 and the concentration meter main body 33 is provided in the introduction pipe 33a. The on-off valve 33d provided in the introduction pipe 33a is configured to open the flow path of the introduction pipe 33a leading from the superheated steam flow pipe 30 to the concentration meter main body 33b when in the open state, and introduce the mixed gas of superheated steam and air introduced from the superheated steam flow pipe 30 into the concentration meter main body 33b. And the on-off valve 33d is configured to close the flow path of the introduction pipe 33a and not introduce the mixed gas from the superheated steam flow pipe 30 into the concentration meter main body 33b when in the closed state. The operation of the on-off valve 33d is configured to be controlled by the controller 34. When the volume flow rate Vw of superheated steam is measured in the measuring device 10, the controller 34 controls the on-off valve 33a to be in the open state. For this reason, when the volume flow rate Vw of superheated steam is measured by the measuring device 10, the mixed gas of superheated steam and air introduced from the superheated steam flow pipe 30 is introduced into the concentration meter main body 30b through the introduction pipe 33a. Also, when the volume flow rate Vw of superheated steam is not measured in the measuring device 10 and the heat treatment of the workpiece 100 in the heat treatment device 1 is performed, the controller 34 controls the on-off valve 33d to be in the closed state. For this reason, when the heat treatment of the workpiece 100 in the heat treatment device 1 is performed, the flow path of the introduction pipe 33d is closed, and the introduction of the superheated steam from the superheated steam flow pipe 30 to the concentration meter main body 33b is not performed. When the heat treatment of the workpiece 100 in the heat treatment device 1 is performed, the on-off valve 33d is in the closed state, and since the flow path of the introduction pipe 33d connected to the superheated steam flow pipe 30 is closed, all of the superheated steam flowing through the superheated steam flow pipe 30 is introduced into the heat treatment chamber 11.

[0062] The controller 34 is provided as a control device for controlling the operation of the measuring device 10. The controller 34 is configured to include, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU reads a program corresponding to the processing content from the ROM and expands it in the RAM, and controls the operation of the measuring device 10 in cooperation with the expanded program. Further, the controller 34 is configured to control the operation of the air supply source 15. Based on the control of the controller 34, the air supply source 15 operates to generate compressed air, and air in a compressed air state is supplied from the air supply source 15 to the superheated steam flow pipe 30. Furthermore, the controller 34 is configured to control the operation of the superheated steam generator 14. Based on the control of the controller 34, the superheated steam generator 14 operates to generate superheated steam, and the superheated steam is supplied from the superheated steam generator 14 to the superheated steam flow pipe 30.

[0063] Further, the controller 34 is configured to control the operation of the on-off valve 35a provided in the air supply pipe 35 and the operation of the on-off valve 33d provided in the oxygen concentration meter 33. When the volume flow rate Vw of superheated steam is measured in the measuring device 10, the controller 34 controls the on-off valve 35a provided in the air supply pipe 35 to be in an open state, and also controls the on-off valve 33d provided in the oxygen concentration meter 33 to be in an open state. In this state, superheated steam is supplied to the superheated steam flow pipe 30 from the superheated steam generator 14, and air is supplied from the air supply source 15. Then, the mixed gas of superheated steam and air supplied to the superheated steam flow pipe 30 flows through the superheated steam flow pipe 30. A part of the mixed gas flowing through the superheated steam flow pipe 30 flows into the introduction pipe 33a of the oxygen concentration meter 33, is introduced from the introduction pipe 33a into the concentration meter main body 33b, and the oxygen concentration C2 of the mixed gas is measured in the concentration meter main body 33b. Further, when the volume flow rate Vw of superheated steam is not measured in the measuring device 10 and the heat treatment of the workpiece 100 in the heat treatment device 1 is performed, the controller 34 controls the on-off valve 35a provided in the air supply pipe 35 to be in a closed state, and also controls the on-off valve 33d provided in the oxygen concentration meter 33 to be in a closed state. In this state, only superheated steam is supplied to the superheated steam flow pipe 30. That is, superheated steam is supplied to the superheated steam flow pipe 30 from the superheated steam generator 14, and no air is supplied from the air supply source 15. Then, all of the superheated steam supplied to the superheated steam flow pipe 30 is introduced into the heat treatment chamber 11 without being introduced into the oxygen concentration meter 33.

[0064] Further, the controller 34 is electrically connected to the flow meter 32 and is configured to receive from the flow meter 32 the measured value of the volumetric flow rate Vg of the air measured by the flow meter 32. Further, the controller 34 is electrically connected to the oxygen concentration meter 33 and is configured to receive from the oxygen concentration meter 33 the oxygen concentration C2 of the mixed gas of superheated steam and air measured by the oxygen concentration meter 33. Then, based on the oxygen concentration C1 of the air, which is known to be 21%, the received volumetric flow rate Vg of the air, and the received oxygen concentration C2 of the mixed gas, the controller 34 calculates the volumetric flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30, thereby measuring the volumetric flow rate Vw of the superheated steam. Specifically, the controller 34 is configured to measure the volumetric flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 by calculating the volumetric flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 using the following formula (1) based on the volumetric flow rate Vg of the air measured by the flow meter 32 and the oxygen concentration C2 measured by the oxygen concentration meter 33. Vw = Vg × C1 / C2 - Vg ···· (1) formula

[0065] The controller 34 is configured to measure the volumetric flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 by calculating it using the above formula (1) based on the received volumetric flow rate Vg of the air and the oxygen concentration C2 of the mixed gas, and constitutes the superheated steam volumetric flow rate measuring unit of the present embodiment. Note that the oxygen concentration C2 of the mixed gas flowing through the superheated steam flow pipe 30 is represented by the following formula (2) by the oxygen concentration C1 of the air, which is known to be 21%, the volumetric flow rate Vg of the air supplied to the superheated steam flow pipe 30, and the volumetric flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30. Therefore, based on the following formula (2), the volumetric flow rate Vw of the superheated steam is expressed as in the above formula (1). C2 = {(Vg × C1 / 100) / (Vw + Vg)} × 100 ···· (2) formula

[0066] Note that the controller 34 is provided with, for example, a monitor that displays the measured value of the volume flow rate Vw of the superheated steam measured by calculating in the above (1). By visually recognizing the display of the monitor by an operator (not shown), the volume flow rate Vw of the superheated steam measured in the controller 34 is grasped. Further, the controller 34 may be electrically connected to, for example, a higher-level controller that controls the operation of the heat treatment apparatus 1, and the measured value of the volume flow rate Vw of the superheated steam measured by the controller 34 may be transmitted to the higher-level controller. Thereby, in the higher-level controller that controls the operation of the heat treatment apparatus 1, the volume flow rate Vw of the superheated steam supplied from the superheated steam flow pipe 30 to the heat treatment chamber 11 of the heat treatment apparatus 1 is grasped.

[0067] [Method for Measuring Volume Flow Rate of Superheated Steam] Next, a method for measuring the volume flow rate of superheated steam according to an embodiment of the present invention will be described. FIG. 6 is a flowchart for explaining the method for measuring the volume flow rate of superheated steam according to an embodiment of the present invention. The method for measuring the volume flow rate of superheated steam according to the present embodiment (hereinafter, also simply referred to as "the measurement method of the present embodiment") supplies air and superheated steam to the superheated steam flow pipe 30, measures the volume flow rate Vg of the air supplied to the superheated steam flow pipe 30, and further measures the oxygen concentration C2 of the mixed gas of air and superheated steam flowing through the superheated steam flow pipe 30. Based on the measured volume flow rate Vg and oxygen concentration C2, it is configured as a method for measuring the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30, and is implemented using the measuring device 10 for the volume flow rate of superheated steam.

[0068] Note that the measurement method of the present embodiment is carried out in a state where the heat treatment of the workpiece 100 is not performed in the heat treatment apparatus 1. When the measurement method of the present embodiment is carried out, both the on-off valve 35a provided in the air supply pipe 35 and the on-off valve 33d provided in the oxygen concentration meter 33 are controlled to be in an open state. As a result, superheated steam is supplied from the superheated steam generator 14 to the superheated steam flow pipe 30, and air is supplied from the air supply source 15. Further, the mixed gas of superheated steam and air supplied to the superheated steam flow pipe 30 is introduced into the oxygen concentration meter 33. Then, the volume flow rate Vg of air and the oxygen concentration C2 of the mixed gas are measured, and based on the measured volume flow rate Vg and oxygen concentration C2, the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 is measured.

[0069] When the volume flow rate Vw of superheated steam is measured, the implementation of the measurement method of the present embodiment is stopped. When the implementation of the measurement method of the present embodiment is stopped, both the on-off valve 35a provided in the air supply pipe 35 and the on-off valve 33d provided in the oxygen concentration meter 33 are controlled to be in a closed state. The heat treatment of the object to be treated 100 in the heat treatment apparatus 1 is performed with the on-off valve 35a and the on-off valve 33d closed. That is, when the heat treatment of the object to be treated 100 is performed, no air is supplied to the superheated steam flow pipe 30, and only superheated steam is supplied. Then, the superheated steam supplied to the superheated steam flow pipe 30 is introduced into the heat treatment chamber 11 without being introduced into the oxygen concentration meter 33. When the heat treatment of the object to be treated 100 is performed in the heat treatment apparatus 1, the superheated steam whose volume flow rate Vw has been measured by the implementation of the measurement method of the present embodiment is supplied from the superheated steam generator 14 to the superheated steam flow pipe 30. That is, the superheated steam is supplied from the superheated steam generator 14 to the superheated steam flow pipe 30 under the same supply conditions so that the superheated steam having the same volume flow rate Vw as when the volume flow rate Vw of the superheated steam was measured by the implementation of the measurement method of the present embodiment is supplied to the superheated steam flow pipe 30. For example, a pressure regulating valve is provided at the connection portion of the superheated steam generator 14 to the superheated steam flow pipe 30, or a pressure regulating valve is provided at the upstream end side of the superheated steam flow pipe 30, and the valve opening degree of the pressure regulating valve when performing the heat treatment of the object to be treated 100 is set to the same valve opening degree as when the volume flow rate Vw of the superheated steam was measured by the implementation of the measurement method of the present embodiment. Thereby, when performing the heat treatment of the object to be treated 100, the superheated steam having the same volume flow rate Vw as when the volume flow rate Vw of the superheated steam was measured by the implementation of the measurement method of the present embodiment is supplied to the superheated steam flow pipe 30.

[0070] Referring to FIG. 6, the measurement method of this embodiment includes a gas supply step S1, a gas flow rate measurement step S2, a superheated steam supply step S3, an oxygen concentration measurement step S4, and a superheated steam volume flow rate measurement step S5. In the measurement method of this embodiment, by implementing the above steps S1 to S5, the volume flow rate Vw of the superheated steam supplied to the heat treatment chamber 11 as the supply destination of the superheated steam is measured. In the flowchart of FIG. 6, for convenience, the above steps S1 to S5 are described in order, but the above steps S1 to S5 are performed continuously in parallel.

[0071] Referring to FIGS. 1, 4, and 6, the gas supply step S1 is configured as a step of supplying a gas containing oxygen and having a known oxygen concentration C1 to the superheated steam flow pipe 30. In this embodiment, air is supplied to the superheated steam flow pipe 30 as a gas containing oxygen and having a known oxygen concentration C1. The oxygen concentration C1 of the air supplied to the superheated steam flow pipe 30 is known to be 21%. In the gas supply step S1, air in a compressed air state is continuously supplied from the air supply source 15 to the superheated steam flow pipe 30 through the air supply pipe 35.

[0072] Referring to FIGS. 1, 4, and 6, the gas flow rate measurement step S2 is configured as a step of measuring the volume flow rate Vg of the air, which is the gas supplied to the superheated steam flow pipe 30 in the gas supply step S1. In the gas flow rate measurement S2, the volume flow rate Vg of the air, which is the gas supplied to the superheated steam flow pipe 30 as a gas containing oxygen and having a known oxygen concentration C1 of 21%, is measured by the flow meter 32. That is, the volume flow rate Vw of the air supplied from the air supply source 15 to the superheated steam flow pipe 30 through the air supply pipe 35 is measured by the flow meter 32 provided in the air supply pipe 35. The measured value of the volume flow rate vg of the air measured by the flow meter 32 is transmitted to the controller 34.

[0073] Referring to FIGS. 1, 4, and 6, the superheated steam supply step S3 is configured as a step of supplying superheated steam to the superheated steam flow pipe 30. In the present embodiment, in the superheated steam supply step S3, the superheated steam generated by the superheated steam generator 14 is continuously supplied to the superheated steam flow pipe 30 connected to the superheated steam generator 14.

[0074] Note that when superheated steam is continuously supplied to the superheated steam flow pipe 30 in the superheated steam supply step S3 and air is continuously supplied to the superheated steam flow pipe 30 in the gas supply step S1, the superheated steam and air supplied to the superheated steam flow pipe 30 are mixed in the superheated steam flow pipe 30 to form a mixed gas of superheated steam and air. The mixed gas of superheated steam and air generated by mixing in the superheated steam flow pipe 30 flows downstream through the superheated steam flow pipe 30. Further, the superheated steam flow pipe 30 is heated by the heater 31. Therefore, the mixed gas of superheated steam and air supplied to the superheated steam flow pipe 30 is heated by the superheated steam flow pipe 30 heated by the heater 31 while flowing through the superheated steam flow pipe 30, and a decrease in the temperature of the mixed gas flowing through the superheated steam flow pipe 30 is suppressed.

[0075] Referring to FIGS. 1, 4, and 6, the oxygen concentration measurement step S4 is configured as a step of measuring the oxygen concentration C2 of the mixed gas of air and superheated steam supplied to the superheated steam flow pipe 30 and flowing through the superheated steam flow pipe 30. In the oxygen concentration measurement step S4, the oxygen concentration C2 of the mixed gas of air and superheated steam, which is a gas with a known oxygen concentration C1 supplied to the superheated steam flow pipe 30 and flowing through the superheated steam flow pipe 30, is measured by the oxygen concentration meter 33 provided in the superheated steam flow pipe 30. Further, in the oxygen concentration measurement step S4, since the oxygen concentration C2 of the mixed gas is measured by the oxygen concentration meter 33 provided on the downstream side of the superheated steam flow pipe 30, the oxygen concentration C2 of the mixed gas of superheated steam and air flowing through the superheated steam flow pipe 30 in a substantially uniformly mixed state is measured.

[0076] Referring to FIGS. 1, 4, and 6, the superheated steam volume flow measurement step S5 is configured as a step of measuring the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 by calculating the volume flow rate Vw of the superheated steam using the following equation (1) based on the volume flow rate Vg of the air measured in the gas flow measurement step S2 and the oxygen concentration C2 of the mixed gas measured in the oxygen concentration measurement step S4. Vw = Vg × C1 / C2 - Vg ··· (1)

[0077] In the superheated steam volume flow measurement step S5, the volume flow rate Vg of the air measured by the flow meter 32 in the gas flow measurement step S2 is received by the controller 34. Further, the oxygen concentration C2 of the mixed gas of the superheated steam and the air measured by the oxygen concentration meter 33 in the oxygen concentration measurement step S4 is also received by the controller 34. Then, in the superheated steam volume flow measurement step S5, based on the oxygen concentration C1 of the air, which is known to be 21%, the volume flow rate Vg of the air received by the controller 34, and the oxygen concentration C2 of the mixed gas, the controller 34 calculates the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 using the above equation (1), thereby measuring the volume flow rate Vw of the superheated steam.

[0078] By performing the superheated steam volume flow measurement step S5, the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 is measured. As a result, the volume flow rate Vw of the superheated steam in the mixed gas of the superheated steam and the air flowing through the superheated steam flow pipe 30 and supplied to the supply destination is measured. That is, by performing the superheated steam volume flow measurement step S5, the volume flow rate Vw of the superheated steam that will be continuously supplied from the superheated steam flow pipe 30 to the heat treatment chamber 11 can be measured.

[0079] [Actions and Effects of the Present Embodiment] According to the present embodiment, air, which is a gas containing oxygen and has a known oxygen concentration C1, and superheated steam are supplied to a superheated steam flow pipe 30 that can continuously supply superheated steam to a heat treatment chamber 11 as a supply destination. Further, when air as a gas with a known oxygen concentration C1 of 21% is supplied to the superheated steam flow pipe 30, the volume flow rate Vg of the air is measured. Furthermore, the oxygen concentration C2 of the mixed gas of air and superheated steam flowing through the superheated steam flow pipe 30 is also measured. Then, based on the measurement results of the volume flow rate Vg of the air and the oxygen concentration C2 of the mixed gas, the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe 30 is measured by the formula Vw = Vg × C1 / C2 - Vg. The superheated steam with the measured volume flow rate Vw can be continuously supplied to the heat treatment chamber 11, which is the supply destination of the superheated steam, through the superheated steam flow pipe 30. Note that at the time of filing of the present application, the existence of a flow meter capable of directly measuring the volume flow rate Vw of the superheated steam is not known. However, according to the present embodiment, even if there is no flow meter capable of directly measuring the volume flow rate Vw of the superheated steam, the volume flow rate Vw of the superheated steam continuously supplied to the heat treatment chamber 11 as the supply destination through the superheated steam flow pipe 30 can be measured.

[0080] Therefore, according to the present embodiment, the volume flow rate Vw of the superheated steam continuously supplied to the heat treatment chamber 11, which is the supply destination of the superheated steam, can be measured.

[0081] In the heat treatment apparatus 1, when the object to be heat treated 100 that is heat treated with superheated steam is a ceramic electronic component such as a multilayer ceramic capacitor, a small amount of hydrogen is added to the atmosphere in the heat treatment chamber 11. The circuit of the ceramic electronic component contains metal, and a small amount of hydrogen is added to the atmosphere in the heat treatment chamber 11 to prevent oxidation of the metal during heat treatment. For this reason, when the object to be heat treated 100 is a ceramic electronic component, a small amount of hydrogen is supplied into the heat treatment chamber 11 together with the superheated steam. At this time, in the heat treatment apparatus 1, the concentration of hydrogen may be controlled according to the heat treatment. For this purpose, it is necessary to accurately grasp the volume flow rate Vw of the superheated steam introduced into the heat treatment chamber 11 and the volume flow rates of other gases. On the other hand, according to the present embodiment, the volume flow rate Vw of the superheated steam continuously supplied to the heat treatment chamber 11 can be measured. For this reason, according to the present embodiment, the volume flow rate Vw of the superheated steam introduced into the heat treatment chamber 11 can be accurately grasped, and the concentration of hydrogen can be controlled more accurately.

[0082] Further, according to the present embodiment, the gas containing oxygen, which has a known oxygen concentration C1 and is supplied to the superheated steam flow pipe 30 and mixed with the superheated steam, is air. For this reason, a gas with a known oxygen concentration C1 of 21% can be easily obtained. Also, since the gas supplied to the superheated steam flow pipe 30 is air, the volume flow rate Vg of the gas supplied to the superheated steam flow pipe 30 can also be easily measured.

[0083] Further, according to the present embodiment, since the superheated steam flow pipe 30 is heated by the heater 31, it is possible to suppress a temperature drop of the mixed gas of air as the gas containing oxygen flowing through the superheated steam flow pipe 30 and the superheated steam. For this reason, it is possible to suppress the superheated steam in the mixed gas flowing through the superheated steam flow pipe 30 from condensing.

[0084] [Modification Example] The embodiments of the present invention have been described above. However, the present invention is not limited to the foregoing embodiments, and various modifications can be made and implemented as long as they are within the scope described in the claims. For example, the following modifications may be implemented.

[0085] In the foregoing embodiment, the gas containing oxygen, which is a gas with a known oxygen concentration C1 and is supplied to the superheated steam flow pipe 30 and mixed with the superheated steam, is described by taking air as an example. However, it does not have to be so. The gas supplied to the superheated steam flow pipe 30 and mixed with the superheated steam only needs to be a gas containing oxygen and having a known oxygen concentration C1, and it may be a gas other than air. For example, as the gas containing oxygen and having a known oxygen concentration C1, an oxygen gas composed only of oxygen and having a known oxygen concentration of 100% may be used, or a gas in which oxygen and nitrogen are mixed to have a specific oxygen concentration may also be used.

[0086] In the foregoing embodiment, the heater 31 is provided around the superheated steam flow pipe 30 and is configured to heat the superheated steam flow pipe 30 from the outside as an example. However, it does not have to be so. As a heater for heating the mixed gas flowing through the superheated steam flow pipe 30 provided in the superheated steam flow pipe 30, for example, a heating element disposed inside the superheated steam flow pipe 30 may be provided, and a heater configuration that directly heats the mixed gas of superheated steam and air flowing through the superheated steam flow pipe 30 by this heating element may be implemented.

[0087] In the foregoing embodiment, in the heat treatment apparatus 1, the form in which one measuring device 10 is provided has been exemplified, but it does not have to be like this. In the heat treatment apparatus 1, a form in which a plurality of measuring devices 10 are provided may be implemented. For example, in the heat treatment apparatus 1, one superheated steam generator 14 is provided, and a plurality of supply paths for supplying the superheated steam supplied from the superheated steam generator 14 to the heat treatment chamber 11 are provided, and the measuring device 10 may be provided corresponding to each of the plurality of supply paths. In this case, even if the number of superheated steam generators 14 provided in the heat treatment apparatus 1 is one, the volume flow rate of the superheated steam continuously supplied to the heat treatment chamber 11 through the plurality of supply paths can be measured in each supply path. Therefore, the installation number of the superheated steam 14 can be reduced to reduce the cost.

Industrial Applicability

[0088] The present invention can be widely applied as a method for measuring the volume flow rate of superheated steam, a measuring device for the volume flow rate of superheated steam, and a heat treatment apparatus provided with the measuring device for the volume flow rate of superheated steam.

Explanation of Signs

[0089] 1 Heat treatment apparatus 10 Measuring device for volume flow rate of superheated steam 11 Heat treatment chamber 30 Superheated steam flow pipe 31 Heater 32 Flow meter (gas flow rate measuring unit) 33 Oxygen concentration meter (oxygen concentration measuring unit) 34 Controller (superheated steam volume flow rate measuring unit) S1 Gas supply process S2 Gas flow rate measuring process S3 Superheated steam supply process S4 Oxygen concentration measuring process S5 Superheated steam volume flow rate measuring process

Claims

1. A gas supply step of supplying a gas containing oxygen with a known oxygen concentration C1 to a superheated steam flow pipe, A gas flow rate measurement step of measuring the volume flow rate Vg of the gas supplied to the superheated steam flow pipe, A superheated steam supply step of supplying superheated steam to the superheated steam flow pipe, An oxygen concentration measurement step of measuring the oxygen concentration C2 of a mixed gas of the gas and the superheated steam that is supplied to the superheated steam flow pipe and flows through the superheated steam flow pipe, A superheated steam volume flow rate measurement step of measuring the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe by calculating the volume flow rate Vw of the superheated steam using the following formula (1) based on the volume flow rate Vg measured in the gas flow rate measurement step and the oxygen concentration C2 measured in the oxygen concentration measurement step: A method for measuring the volume flow rate of superheated steam, characterized by comprising the above steps. Vw = Vg × C1 / C2 - Vg... (1)

2. The method for measuring the volume flow rate of superheated steam according to Claim 1, wherein the gas is air.

3. The method for measuring the volume flow rate of superheated steam according to Claim 1 or Claim 2, wherein the superheated steam flow pipe is heated by a heater.

4. A superheated steam flow pipe to which a gas containing oxygen with a known oxygen concentration C1 and superheated steam are supplied, A gas flow rate measurement unit that measures the volume flow rate Vg of the gas supplied to the superheated steam flow pipe, An oxygen concentration measurement unit that measures the oxygen concentration C2 of a mixed gas of the gas and the superheated steam that is supplied to the superheated steam flow pipe and flows through the superheated steam flow pipe, A superheated steam volume flow rate measurement unit that measures the volume flow rate Vw of the superheated steam supplied to the superheated steam flow pipe by calculating the volume flow rate Vw of the superheated steam using the following formula (1) based on the volume flow rate Vg measured by the gas flow rate measurement unit and the oxygen concentration C2 measured by the oxygen concentration measurement unit: A device for measuring the volume flow rate of superheated steam, characterized by comprising the above components. Vw = Vg × C1 / C2 - Vg... (1)

5. The device for measuring the volume flow rate of superheated steam according to Claim 4, wherein the gas is air.

6. A measuring device for the volumetric flow rate of superheated steam according to claim 4 or claim 5, wherein the superheated steam flow pipe is heated by a heater, and the measuring device for the volumetric flow rate of superheated steam. **Claim 7** A heat treatment apparatus for heating an object to be treated with superheated steam to perform heat treatment on the object to be treated, a heat treatment chamber in which the heat treatment of the object to be treated is performed, a measuring device for the volumetric flow rate of superheated steam according to any one of claims 4 to 6, comprising: wherein the heat treatment chamber is characterized in that superheated steam supplied through the superheated steam flow pipe is introduced, and the heat treatment apparatus.

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