WO1998029685A1

WO1998029685A1 - Superheated steam generator

Info

Publication number: WO1998029685A1
Application number: PCT/JP1997/004781
Authority: WO
Inventors: Yasuzo Kawamura; Yoshitaka Uchihori
Original assignee: Kabushiki Kaisha Seta Giken; Omron Corporation
Priority date: 1996-12-26
Filing date: 1997-12-22
Publication date: 1998-07-09

Abstract

An electromagnetic induction heating type superheated stream generator provided with a first electromagnetic induction heater heating a liquid into steam and a second electromagnetic induction heater superheating the steam. These first and second electromagnetic induction heaters are provided with pipes made of non-magnetic materials, coils wounded on the pipes, and heaters heated by the electromagnetic induction of the coils contained in the pipes respectively. The liquid is evaporated by the first electromagnetic induction heater and the steam is superheated by the second electromagnetic induction heater, the respective heaters being separate from each other.

Description

Specification

Technical field

The present invention relates to a superheated steam producing apparatus for generating superheated steam used for home and industrial use by an electromagnetic induction heating method. Background art

Superheated steam is obtained by further heating saturated steam and raising it to a predetermined temperature. For example, the temperature of saturated steam under atmospheric pressure is 100 ° C, but when it is further heated to 300 ° C, it becomes superheated steam.

Superheated steam, which is used in large quantities for industrial purposes, is produced by generating saturated steam in the boiler body and heating it further with a super heater. This superheater is installed in the high-temperature part of the furnace, and is installed in the radiant superheater, which heats the steam by receiving the radiant heat of the flame, and in the middle of the boiler flue, Contact vent superheaters have been used that superheat steam by contact. An industrial superheated steam production apparatus requires a complicated superheater in addition to a large-sized boiler body, and thus has a problem that the entire apparatus becomes a large-scale apparatus.

For home use, for example, a steam generator disclosed in Japanese Utility Model Publication No. 60-26243 is used. The steam generator disclosed in this publication includes a cylindrical boiler, a first heating coil wound below the outer periphery of the boiler, and a second heating coil wound above the outer periphery of the boiler. It becomes. The water stored under the boiler is heated by the heat transfer from the first heating coil, and the steam reaching the upper part of the boiler is further heated by the heat transfer from the second heating coil. Such household steam Air generators have the problem that they require installation space for inefficiency.

The present invention has been made in view of such problems of the related art, and an object of the present invention is to provide a superheated steam production apparatus having a compact device configuration and capable of efficiently generating superheated steam. Is to provide. Disclosure of the invention

The present invention was completed based on the idea that if the inventor further improved the heating device previously proposed in Japanese Patent Application Laid-Open No. 3-98286, it would be optimal for a superheated steam generator.

The superheated steam generator of the present invention has a first electromagnetic induction heating unit that heats a liquid to produce a vapor, and a second electromagnetic induction heating unit that heats the vapor, and the first and second electromagnetic inductions Each of the heating units includes a pipe made of a non-magnetic material, a coil wound around the pipe, and a heating element housed in the pipe and heated by electromagnetic induction by the coil.

The first electromagnetic induction heating section turns the liquid into steam, and the second electromagnetic induction heating section heats the steam. The use of a heating element with a large liquid or vapor contact area that allows the fluid or gas to be dispersed, diffused, dissipated, and volatilized regularly provides extremely high heat exchange properties for the entire device. As the height increases, the equipment becomes compact, and the entire equipment can be installed in the middle of piping. Therefore, pure superheated steam at a predetermined temperature and a predetermined pressure can be continuously obtained with a simple device configuration.

The heating element is preferably a laminate formed by electrical bonding so as to have a passage crossing in the axial direction.

A fluid or vapor is regularly dispersed, diffused, dissipated, and volatilized by passages in a direction crossing the axial direction. As a result, the entire laminate heats uniformly. Therefore, the production efficiency of superheated steam can be improved.

The first electromagnetic induction heating section and the second electromagnetic induction heating section are configured separately, and a first type of superheated steam production apparatus in which both are connected by piping can be provided. In this first type of superheated steam production apparatus, it is preferable that the pipe of the first electromagnetic induction heating section is disposed upward and the pipe of the second electromagnetic induction heating section is disposed laterally. By separating the first electromagnetic induction heating section and the second electromagnetic induction heating section and connecting them with piping, it is possible to select an appropriate equipment arrangement for steam generation and an appropriate equipment arrangement for steam overheating. .

The pipe in the first electromagnetic induction heating section and the pipe in the second electromagnetic induction heating section can be a second type of superheated steam production apparatus which is common. In the second type of superheated steam generator, a member for preventing steam from being blown up is provided between the heating element in the first electromagnetic induction heating section and the heating element in the second electromagnetic induction heating section. Are preferred. The whole becomes compact. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a device configuration diagram of a superheated steam production device of the present invention, FIG. 2 is a device configuration diagram of another superheated steam production device of the present invention, and FIG. 3 is a diagram of FIG. FIG. 4 is a diagram showing a device configuration in a case where a circulation line is provided in a superheated steam production device, FIG. 4 is a device configuration diagram of still another superheated steam production device of the present invention, and FIG. FIG. 6 is a perspective view, FIG. 6 is a structural diagram of the laminate, FIG. 7 is a diagram showing a heat generation state of the laminate, and FIG. 8 is a sectional view of an electromagnetic induction heating unit. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In Fig. 1, 1 is the first electromagnetic induction heating section, 2 is the second electromagnetic induction heating section, 101 is a level control port, 102 is an automatic water supply valve, and 103 is a safety valve. A pressure setting valve that functions as

In each of the first and second electromagnetic induction heating sections 1 and 2, a coil is wound around a pipe 6 made of a non-magnetic material as a fluid passage, and a heating element 8 made of a magnetic material is housed in the pipe 6. It is formed. The coil 7 is formed by twisting a litz wire, and is wound around the outer circumference of the pipe 6 or wound and embedded in the thickness of the pipe 6. The pipe 6 has a function of holding the coil 7, defining a fluid passage, and storing a heating element 8 that generates heat by electromagnetic induction in the passage. Therefore, the pipe 6 is formed of a nonmagnetic material having corrosion resistance, heat resistance, and pressure resistance. Specifically, inorganic materials such as ceramics, resin materials such as FRP (fiber reinforced plastic) and fluororesin, and non-magnetic metals such as stainless steel are used as the material of the pipe 6. Particularly, ceramics are used. Most preferred.

The pipeline is composed of a first line 110 that brings a liquid such as tap water at 20 ° C to the first electromagnetic induction heating section 1 and a second line 1102 that vaporizes the liquid from the first electromagnetic induction heating section 1. It comprises a second line 11 1 leading to the electromagnetic induction heating section 2 and a third line 112 leading the superheated steam from the second electromagnetic induction heating section 2 to a use section such as a sauna.

The amount of tap water reaching the electromagnetic induction heating section 1 can be controlled by the level controller 101 and the automatic water supply valve 102. By this control system, the first electromagnetic induction heating unit 1 is controlled so that tap water having a predetermined liquid level always exists in a boiling state. The 100 ° C. saturated steam generated by evaporation in the first electromagnetic induction heating section 1 is further heated in the second electromagnetic induction heating section 2, for example. For example, it becomes superheated steam of 300 ° C. The amount of superheated steam obtained can be controlled by the input power to the first electromagnetic induction heating unit 1. If the input power to the first electromagnetic induction heating unit 1 is large, a large amount of water can be boiled, and if the input power to the first electromagnetic induction heating unit 1 is small, water can be boiled little by little. The temperature of the superheated steam can be controlled by the input power to the second electromagnetic induction heating section 2. When the input power to the second electromagnetic induction heating unit 2 is large, high-temperature superheated steam is obtained, and when the input power to the second electromagnetic induction heating unit 2 is small, low-temperature superheated steam is obtained.

The pressure setting valve 103, which functions as a safety valve, is set at, for example, 1.1 atm. The safety of the equipment is ensured by preventing the pressure of the entire apparatus from rising above the design pressure. In the case where the supply destination is a sauna as shown in the figure, the pressure in the apparatus becomes atmospheric pressure because the pressure of the supply destination is atmospheric pressure.

FIG. 2 is a diagram showing the equipment configuration of another superheated steam production device. The difference from FIG. 1 is that the pipe 6 of the first electromagnetic induction heating section 1 is arranged upward and the pipe 6 of the second electromagnetic induction heating section 2 is arranged sideways. There is an advantage that the blow-up of steam from the first electromagnetic induction heating section 1 is prevented at the bent portion of the second line 11 1 at about 90 °. The horizontal orientation is also advantageous in terms of heating the drain that accumulates in the heating element 8 of the second electromagnetic induction heating section 2 at the beginning of operation.

FIG. 3 is a view of the equipment configuration in the case where a circulation line 16 is provided in the superheated steam production apparatus of FIG.

The superheated steam production apparatus shown in FIG. 3 includes a second line 111 connecting the first electromagnetic induction heating section 1 and the second electromagnetic induction heating section 2, and the first electromagnetic induction heating section 1 And a circulation line 16 for returning the liquid component mixed with the steam blown up to the first line 110 which is a liquid introduction line to the first electromagnetic induction heating unit 1. . The second line 11 1 is a horizontal line 11 1 a for temporarily leading the steam blown up from the first electromagnetic induction heating unit 1 in a horizontal direction, and a gas component of the steam guided in the horizontal direction. And a vertical line 111b that is bent upward from the horizontal line to stand up. The circulation line 16 extends downward from the bent portion of the second line 11 1 together with the second line 11 1 so as to form a T-shaped laterally branched portion 16 a. And is connected to the first line 110 side.

According to the superheated steam production apparatus having such a circulation line 16, the steam blown up from the first electromagnetic induction heating section 1 is guided laterally by the horizontal line 111a of the second line 111. However, since it collides with the wall of the branch part 16a, it is possible to prevent steam from directly blowing up to the second electromagnetic induction heating part 2. In addition, vapor hitting the wall of the branch section 16a separates gas and liquid there, and the liquid returns to the first electromagnetic induction heating section 1 through the circulation line 16 while the gas passes through the second line. To the second electromagnetic induction heating section 2 through the vertical line 1 1 1b of the pin 1 1 1. FIG. 4 is a diagram showing the configuration of another superheated steam production apparatus. The difference from FIG. 1 is that the first heating element 8A and the second heating element 8B are inserted in series through a distributor 104 in a single pipe 6. The first coil 7A for the first heating element 8A and the second coil 7B for the second heating element 8B are separately arranged on the outer periphery of the pipe 6 of FIG. The distributor 104 functions as a member for dispersing the steam in a cross section perpendicular to the axis and at the same time, preventing the steam from being blown up from the first heating element 8B. In this device having such a configuration, the lower half of the pipe 6, the first heating element 8A and the first coil 7A form the first electromagnetic induction heating section 1, and the upper part of the pipe 6 The half, the second heating element 8B, and the second coil 7B form the second electromagnetic induction heating section 2. Even in such a device, the electric power sufficient to evaporate the fluid is supplied from the first coil 7A, and the electric power sufficient to overheat the steam is supplied from the second coil 7B. As a result, a predetermined amount of superheated steam can be obtained at a predetermined temperature as in the case of the present apparatus shown in FIG. Note that the first electromagnetic induction heating section 1 and the second electromagnetic induction heating section 2 are divided into a first heating element 8A and a second heating element 8B, which are integrally formed as a single piece. The classification may be such that the steam generation part and the steam superheated part are separately controlled by A and the second coil 7B.

FIG. 5 shows the structure of the heating element 8 incorporated in the apparatus main body 1. The heating element 8 is formed by alternately stacking the first metal plates 31 and the flat second metal plates 32 bent in a zigzag mountain shape to form a cylindrical laminate as a whole. As a material of the first metal plate 31 and the second metal plate 32, a martensitic stainless steel such as SUS447J1 is used. Any material that can be subjected to electromagnetic induction heating, such as non-metallic materials such as conductive carbon and ceramics, can be used.

As shown in FIG. 6, the peak (or valley) 33 of the first metal plate 31 is disposed so as to be inclined by an angle α with respect to the center axis 34, and sandwiches the second metal plate 32. The peaks (or valleys) 33 of the first metal plates 31 adjacent to each other are arranged to intersect. Then, at the intersection of the peaks (or valleys) 33 of the adjacent first metal plates 31, the first metal plate 31 and the second metal plate 32 are welded by spot welding, and are electrically connected to each other. Have been.

As a result, a first small flow path 35 inclined by an angle of “1” is formed between the first metal plate 31 and the second metal plate 32 on the near side, and the second metal plate 32 and the rear A second small flow path 36 inclined by an angle of 1 ° is formed between the first metal plate 31 and the first small flow path 35 and the second small flow path 36. Also, holes 37 are provided on the surfaces of the first metal plate 31 and the second metal plate 32 as third small flow paths for generating turbulent flow of fluid. Further, the surfaces of the first metal plate 31 and the second metal plate 32 are not smooth, and are provided with fine irregularities 38 by satin finishing or embossing. Mountain ( Or valley) 33 Negligibly small compared to the height of 3.

When a high-frequency current is applied to the coil 7 and a high-frequency magnetic field is applied to the heating element 8, an eddy current is generated in the entire first metal plate 31 and the second metal plate 32, and the heating element 8 generates heat. At this time, as shown in FIG. 7, the temperature distribution is an eyeball shape extending in the longitudinal direction of the first metal plate 31 and the second metal plate 32, and the center portion generates heat more than the peripheral portion. In addition, it is advantageous for heating a fluid (liquid or vapor) that is going to flow in the center.

Also, as shown in FIG. 6, a first small flow path 35 and a second small flow path 36 that intersect are formed in the heating element 8, and fluid diffusion between the periphery and the center is performed. As a result, the presence of the hole 37 forming the third small passage also causes fluid diffusion in the thickness direction between the first small passage 35 and the second small passage 36. Therefore, these small channels 35, 36, and 37 cause macroscopic dispersion, dissipation, and volatilization of the fluid (liquid or vapor) throughout the heating element 8. In addition, microscopic diffusion, emission, and volatilization occur due to minute irregularities 38 on the surface. As a result, the fluid passing through the heating element 8 becomes a substantially uniform flow, and a uniform chance of contact between the first metal plate 31 and the second metal plate 32 and the fluid is obtained. Heating is ensured.

By the way, it is preferable that the thickness of the metal plates 31 and 32 is not less than 30 microns and not more than lrnm, and the frequency of the high-frequency current generated by the high-frequency current generator is in the range of 15 to 150 KHz. When the thickness of the metal plate is 30 micron or more and 1 mm or less, it is easy to supply power, and it is easy to secure a small flow path by processing a waveform or the like to increase a heat transfer area. If the frequency used is in the range of 15 KHz to 15 OKHz, copper loss of the coil 7 and loss of the switching element can be prevented. In particular, the frequency band with low loss is 20 to 7 OKHz. The heating element 8 preferably has a heat transfer area of 2.5 square centimeters or more per cubic centimeter. . Heat exchange efficiency can be increased by stacking metal plates so that the surface area per cubic centimeter of the heating element 8 is 2.5 square centimeters or more, more preferably 5 square centimeters or more. . Further, it is preferable that the amount of fluid to be heated per square centimeter of the surface area of the heating element 8 is not more than 0.4 cubic centimeter. If the fluid volume per square centimeter of the surface area of the heating element 8 is set to 0.4 cubic centimeter or less, more preferably 0.1 cubic centimeter or less, rapid response of heat transfer to the fluid can be obtained.

Next, the detailed structure of the electromagnetic induction heating section 1 that can be incorporated in-line into the pipeline will be described with reference to FIG. The electromagnetic induction heating section 1 is mainly composed of flanges 3A and 3B, a pipe 6 made of silicon nitride, a coil 7, and a heating element 8. For example, a chemical blunt is installed in the middle of pipelines 121 and 122 so that liquid or vapor 14 flows from the lower side to the upper side. The power unit 11 is connected to the coil 7 of the electromagnetic induction heating unit 1 or the coils 7 of the plurality of electromagnetic induction heating units 1, and the control unit 12 is connected to the power unit 11. The temperature sensor 13 is connected to the control unit 12 to form a heating system. This temperature sensor 13 is used for controlling when the steam is overheated. The control unit 12 can control the electric power unit 11 so that the superheated steam has a predetermined temperature.

The silicon nitride pipe 6 is manufactured integrally so that the flanges 6b and 6c are located at both ends of the body 6a. The manufacturing process consists of molding, sintering, processing, etc.The molding process is injection molding, slip casting, etc.The sintering process is a nitrogen process that can use high temperatures while suppressing decomposition of silicon nitride. It is a sintering method under gas pressure, and the processing steps are electric discharge machining and laser machining. In other words, the pipe is made into the shape shown in the figure by injection molding, sintering and hardening by sintering. The body 6a is manufactured to have a predetermined inner diameter and a predetermined thickness. The outer periphery of the flanges 6 b and 6 c at both ends is formed so that the contact surfaces 6 d and 6 e of the packings 4 and 5 and the hooks 6 f and 6 g for the flanges 3 A and 3 B are formed. Manufactured with the minimum required diameter. The flanges 3A and 3B have a structure that can be split into two parts.For example, the semicircular member is hinged so that it can be opened and closed, and a fixing means that can fix the semicircular member in a closed state is provided. is there. The flanges 3A and 3B are provided with holes for bolts at equal circumferential positions. Can be.

These flanges 3 A and 3 B hold the flanges 6 b and 6 c of the pipe 6 and are bolted to the flanges 1 2 3 and 1 2 4 at the end of the pipes 1 2 1 and 1 2 2. Concluded by 9 and nut 10. Then, the contact surfaces 6 d and 6 e of the flanges 6 b and 6 c are pressed tightly to the contact surfaces of the flanges 1 2 3 and 1 2 4 via the packings 4 and 5, and both sealing and joining are performed. . The material of the flanges 3A and 3B is made of an austenitic stainless steel such as nonmagnetic SUS316 so as to be hardly affected by the magnetic flux formed by the coil 7. A temperature sensor 13 can be attached to a pipeline 122 located on the outflow side of the liquid or vapor 14 via a socket.

A heating element 8 is accommodated in the pipe 6, and a coil 7 is wound around the pipe 6 at a position facing the heating element 8. The heating element 8 has a diameter D so as to form an annular gap R s between its outer peripheral surface and the inner peripheral surface of the pipe 6, and its axis coincides with the axis of the heating element 8 in the pipe 6. It is loosely fitted so as to be inserted, inserted into the pipe 6, and held by the holding members 42, 43. The diameter D of the heating element 8 is determined by the amount by which the pipe 6 thermally expands in the radial direction when the liquid or steam 14 is heated by the electromagnetic induction heating section 1 and the heat generation. It is determined that there is an annular gap Rs between the heating element 8 and the pipe 6 that is equal to or greater than the difference in thermal expansion between the heating element 8 and the pipe 6 in the radial direction.

The ring-shaped stopper 35 is made of non-magnetic, heat-resistant and corrosion-resistant ceramic or the like, and is fitted into the pipe 6 from the liquid or vapor 14 outflow side. The heating element 8 is fixed to the heating element 8 with a gap Vs equal to or slightly smaller than the amount of thermal expansion in the axial direction of the heating element 8. The ring-shaped stopper 35 is located on the heating element 8 across the annular gap Rs in the radial direction from the outflow side, and is connected to the heating element 8 by the thermal expansion of the heating element 8. At the same time, the annular gap Rs is closed from the outflow side. The upper holding member 42 holds the stopper 35 with a square bar 42c, and holds the square bar 42c through a vertical bar 42b and a horizontal bar 42a. It is fixed to. The lower holding member 43 holds the lower end center of the heating element 8 with a vertical bar 43b, and fixes the vertical bar 43b to the pipeline 122 via a horizontal bar 43a.

When the liquid or steam 14 flows from the inflow side to the outflow side of the electromagnetic induction heating section 1 and the liquid or steam 14 is heated via the pipe 6 and the heating element 8 by electromagnetic induction heating by the coil 7, the pipe 6 There is a difference in the thermal expansion in the radial direction of the heating element 8 and the annular gap Rs is formed between the pipe 6 and the heating element 8. While absorbing the difference in thermal expansion, the effect of stress caused by the heating element 8 coming into contact with and pushing the pipe 6 is prevented, and the heating element 8 also thermally expands in its axial direction. The gap Vs formed between the ring stopper 35 and the ring-shaped stopper 35 is absorbed by thermal expansion.

At this time, the liquid or vapor 14 flowing from the pipeline 12 21 to the inflow side of the device 1 flows into the heating element 8 and is heated and flows to the outflow side, and at the same time, a part of the liquid or vapor 14 Flows into the annular gap R s directly from the inflow side or from the heating element 8 to flow to the inflow side through the annular gap R s However, when the heating element 8 engages with the ring-shaped stopper 35 by thermal expansion in the axial direction, the outflow side of the annular gap Rs is closed, and the fluid 14 flows directly to the outflow side. As a result, the flow of the fluid 14 from the inflow side generates a pressure in the annular gap R s that pushes the fluid to the outflow side, and the liquid or vapor 14 flowing into the annular gap R s Can flow into the heating element 8 by this pressure.

Thereby, even if the heating element 8 is heated by the electromagnetic induction heating by the coil 7, the breakage of the pipe 6 due to the thermal expansion of the heating element 8 can be prevented, and the annular gap for absorbing the thermal expansion of the heating element 8 can be prevented. Even if Rs is formed, the heating element 8 thermally expands and engages with the ring stopper 35 to close the annular gap Rs from the outflow side, and flows out into the annular gap Rs. Since the liquid or vapor 14 can flow into the heating element 8, the liquid or vapor 14 can be uniformly heated by the heating element 8.

In the heating by the heating element 8 having the above-described structure, it has been confirmed that the conversion efficiency from electric energy to heat energy is extremely high at 92%. For example, when a heating element 8 having a diameter of 100 mm, a length of 200 mm, and a surface area of 2.2 to 6.2 m ² is used, the film thickness of the fluid (the amount of water film per 1 cm ³ ) is 0. Since it is extremely thin, having a thickness of 5 to 0.2 mm, and the metal plates 31 and 32 constituting the heating element 8 are also thin, the temperature difference of the fluid is extremely small, and heat is quickly transferred to the fluid. Industrial applicability

The sauna is used as an example of using superheated steam. However, this device can be used for cooking food with superheated steam and cleaning metal parts using superheated steam.

In addition, if this device can be heated to a temperature exceeding 300 ° C, a chemical device that separates oxygen and hydrogen by heating water vapor to 800 ° C or more at normal pressure. It can also be used as a device. If a conductive ceramic capable of electromagnetic induction heating is used as a heat generating element to enable such high-temperature overheating, magnetic transformation of the metal constituting the heat generating element at a high temperature does not occur.

Although the superheat of steam as a liquid has been described, the present apparatus is applicable to liquids of hydrocarbons having a boiling point other than water.

In addition to superheated steam, high-pressure superheated steam can be generated by using a pressure-resistant structure for each component of this device in addition to atmospheric pressure.

Claims

The scope of the claims

1. It has a first electromagnetic induction heating unit that heats a liquid to produce a vapor, and a second electromagnetic induction heating unit that heats the vapor.

Each of the first and second electromagnetic induction heating sections includes a pipe made of a non-magnetic material, a coil wound around the pipe, and a heating element housed in the pipe and heated by electromagnetic induction by the coil. A superheated steam production apparatus comprising:

2. The superheated steam production apparatus according to claim 1, wherein the heating element is a laminate formed by electrical connection so as to have a passage crossing in the axial direction.

3. The superheated steam product according to claim 1 or 2, wherein the first electromagnetic induction heating section and the second electromagnetic induction heating section are configured separately, and both are connected by a pipe.

4. The superheated steam production apparatus according to claim 3, wherein the pipe of the first electromagnetic induction heating section is disposed upward, and the pipe of the second electromagnetic induction heating section is disposed laterally.

5. The method according to claim 1, wherein the pipe in the first electromagnetic induction heating section and the pipe in the second electromagnetic induction heating section are common.

6. The superheated steam production apparatus according to claim 5, wherein a member for preventing steam from being blown up is provided between the heating element in the first electromagnetic induction heating section and the heating element in the second electromagnetic induction heating section. .