JP3642415B2 - Fluid heating device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for heating a substance having fluidity (collectively referred to as a fluid) such as a gas, a liquid, a granular material, or a mixture (dispersion) thereof, and is particularly suitable for superheating of steam. The present invention relates to a fluid heating device.
[0002]
[Prior art]
Conventionally, various devices for heating a fluid have been used, and a heating device such as a boiler using combustion gas is usually used for high temperature heating such as several hundred degrees. However, since a heating apparatus such as a boiler using combustion gas is large in size, it is suitable for heating a large amount of fluid, but not suitable for heating a small amount of fluid.
[0003]
Therefore, as a small device capable of heating a small amount of fluid to a high temperature, a heating device using induction heating capable of rapid and high temperature heating has been proposed. For example, a casing or tube that passes or contains fluid is made of a conductive material, the casing or tube is heated by induction heating, and the fluid is heated, or the fluid passes or A structure in which a heating element made of a conductive material is arranged inside a casing or a tube to be housed, and the heating element is heated by induction heating to heat the fluid (for example, see JP-A-9-167679) )
[0004]
[Problems to be solved by the invention]
However, these conventional heating devices using induction heating have the following problems. That is, in the method of generating heat in the casing or the tube itself, the contact area between the heat generating body (tube body) and the fluid cannot be increased so much that rapid and uniform heat input to the fluid cannot be performed. There was a problem that it was difficult to reduce the size.
[0005]
On the other hand, in the system in which a heating element is arranged in a casing or a tube and the heating element generates heat, by adopting a structure in which corrugated plates are laminated on the heating element, the contact area with the fluid can be increased, When the heating element generates heat uniformly, heat input to the fluid can be performed rapidly and uniformly, and the apparatus can be miniaturized. However, since a heating element such as a structure in which corrugated plates are laminated has a structure in which the corrugated plates are electrically connected to each other, an induction current is generated when induction heating is performed by an induction coil arranged so as to surround the heating element. Flows preferentially to the loop electric circuit formed in the outer peripheral portion by the corrugated plate connection, does not reach the central portion, and the central portion does not generate heat. For this reason, the central part of the heating element is only heated by heat transfer from the outer peripheral part, the temperature is always lower than that of the outer peripheral part, and the heat input distribution to the fluid is also uneven. That is, there is a problem that rapid and uniform heat input to the fluid cannot be performed, and the heating efficiency of the fluid cannot be sufficiently increased.
[0006]
The present invention has been made in view of such problems, and in an apparatus for heating a fluid by induction heating of a heating element that contacts the fluid, the contact area between the heating element and the fluid is increased and the heating element is uniformly heated. Accordingly, it is an object of the present invention to provide a small-sized fluid heating apparatus that can heat a fluid efficiently and uniformly.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention distributes a plurality of tubes made of a conductive material for acting as a heating element in parallel to each other and in a direction from the outer periphery to the center of the tube group. The arranged tube group is formed, and the fluid to be heated is passed only inside each tube body, and an induction coil is arranged so as to surround the tube group, thereby inductively heating a plurality of tube bodies. Furthermore, by arranging the plurality of tubes in a non-contact state, the alternating magnetic field generated by the induction coil can enter the central portion of the tube group, and each tube including the central portion The induction current flowing in the circumferential direction is generated, and the tube located at least in the outer peripheral region of the tube group is made of a non-magnetic material, thereby reducing the attenuation of the alternating magnetic field to the center. It is a thing. With this configuration, a large number of small-diameter pipes can be arranged in a small space, so that the contact area of the pipes with the fluid (inner area of the pipes) can be increased, and the circumferential direction in each pipe body Inductive current flowing through the substrate can be efficiently generated and induction heated, the fluid can be heated uniformly with high efficiency, and the apparatus can be downsized.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
A fluid heating device according to an embodiment of the present invention is a tube group composed of a plurality of conductive material tube bodies arranged in parallel without being in contact with each other, and is centered from the outer periphery of the tube group. A tube group arranged so that the tubes are distributed also in the direction of the depth, a fluid supply / discharge means for supplying and discharging a fluid to and from the plurality of tubes, and arranged so as to surround the tube group An induction coil, and a tube located in at least an outer peripheral region of the tube group is made of a non-magnetic material, and a fluid flows continuously through the plurality of tubes, or In a state where the fluid is filled in the tubular body and the flow is stopped, the tubular body is inductively heated by the induction coil to generate heat, and the internal fluid can be efficiently heated.
[0009]
Here, when arranging a plurality of tubular bodies, a large number of tubular bodies are arranged in a small space by adopting a method in which the tubular bodies are distributed in the depth direction from the outer periphery of the tubular body group toward the center. The device can be made compact by increasing the contact area with the fluid. In addition, by arranging a plurality of tubes in a non-contact state, an alternating magnetic field generated by the induction coil can enter the central portion of the tube group, and an induced current flowing in the circumferential direction of each tube is generated. In addition, the tubular body positioned at least in the outer peripheral region of the tubular body group is made of a non-magnetic (relative magnetic permeability≈1) conductive material, so that the attenuation of the alternating magnetic field to the center portion is reduced. The magnetic field is much smaller than when the body is ferromagnetic, and an alternating magnetic field having a strength capable of sufficiently induction-heating the tube in the region enters the central region. Thus, the plurality of tubes can generate heat efficiently and substantially uniformly, not only those arranged in the outer peripheral region but also those arranged in the central region, and can heat the fluid inside thereof efficiently and uniformly. . In addition, when the number of tubes used is increased, and the approach of the alternating magnetic field to the central region becomes small, a core material such as an iron core is arranged in the center, and the alternating magnetic field is collected in the central region. Also good.
[0010]
The arrangement of the tubes in the tube group is arbitrary as long as the tubes are distributed in the depth direction from the outer periphery to the center so that space efficiency can be increased. It is preferable to adopt. When tubes are arranged in multiple rings, the uniformity of the tube induction current when a cylindrical induction coil is placed outside the tube group adjusts the ratio of the number of tubes arranged in each ring of the multiple ring array. This can be done easily.
[0011]
In order to prevent heat dissipation and increase thermal efficiency, it is preferable to place a heat insulating material around the tube group, but at that time, heat insulation is provided between the tube group and the induction coil and at two places outside the induction coil. It is preferable to arrange the material. The heat insulating material arranged inside the induction coil also serves to prevent the induction coil itself from being heated due to heat radiation from the heated tube and preventing the temperature from being excessively raised, thereby eliminating the cooling of the induction coil. Since it is desirable to arrange the induction coil as close to the tube as possible from the viewpoint of induction heating efficiency, the thickness of the heat insulating material inside the induction coil should be within a range that can secure the thickness necessary to protect the induction coil. It is preferable to make it as thin as possible. Moreover, this heat insulating material can also be used as a holding member for hold | maintaining an induction coil by employ | adopting the material with appropriate intensity | strength for this heat insulating material.
[0012]
In the case of heating while flowing fluid through a plurality of pipes, the form of flowing the fluid to the plurality of pipes is a form in which the fluid flows through the plurality of pipes in parallel, a form in which the fluid flows in series, or a form in which parallel and series are used in combination Any of them may be used, but it is preferable to make all the pipes flow in parallel because pressure loss can be reduced and the structure of the apparatus can be simplified. In the case of adopting a configuration in which fluids flow in parallel to a plurality of tubes, as an embodiment of the fluid supply / discharge means, a tube plate that is held through one end side of the plurality of tubes, and an outer surface side of the tube plate A fluid supply header having a housing with a fluid inlet attached to the tube, a tube plate held through the other end of the plurality of tubes, and a fluid outlet attached to the outer surface side of the tube plate A configuration including a fluid discharge header having a housing may be mentioned. With this structure, a large number of tubes and fluid supply headers and fluid discharge headers at both ends thereof can be integrated to form a compact fluid heating apparatus.
[0013]
In the fluid heating apparatus having the above-described configuration, it is preferable to dispose a baffle such as a corrugated plate in the pipe body in order to disturb the fluid flowing inside. When a baffle such as this corrugated plate is arranged, the fluid flowing through the tube is disturbed, so the heat transfer coefficient between the tube inner surface and the fluid is greatly improved, and the amount of heat transfer can be increased.
[0014]
The fluid heating device of the present invention can be used for heating any fluid. In particular, since the tube body can be heated to a high temperature and quickly, high temperature heating such as heating a gas to several hundred degrees, for example, Suitable for use in steam superheating.
[0015]
【Example】
Hereinafter, preferred embodiments of the present invention shown in the drawings will be described. FIG. 1 is a schematic sectional view taken along the central axis of a fluid heating apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view perpendicular to the central axis of the fluid heating apparatus. A fluid heating apparatus generally indicated by reference numeral 1 includes a tube group 2A composed of a large number of tube bodies 2, a fluid supply header 3 for supplying fluid to one end of the tube body 2, and a fluid from the other end of the tube body 2. A fluid discharge header 4, a first heat insulating material 5 disposed so as to surround the tube group 2A, an induction coil 6 disposed outside the second heat insulating material 7, and a second heat insulating material 7 disposed further outside. It has.
[0016]
A large number of the tube bodies 2 are arranged in parallel with each other in a non-contact manner and in a multiple manner between the outer periphery of the tube body group 2A and the center O. More specifically, the multiple tube bodies 2 are arranged in multiple rings, that is, on a plurality of concentric circles 10a, 10b, and 10c. The tube body 2 is also arranged at the center. With this configuration, a large number of tube bodies 2 can be efficiently arranged in a circle having a constant diameter. In addition, you may arrange | position an iron core instead of arrange | positioning the pipe body 2 in the center. The tube body 2 is for heating the fluid that is heated by induction and passes through the inside thereof. Of course, the tube body 2 is made of a material having conductivity and necessary heat resistance so that induction heating is possible. Yes. Further, the tubular body 2 is non-magnetic (relative magnetic permeability≈1) so that the alternating magnetic field generated by the induction coil 6 does not attenuate the alternating magnetic field so much when entering the central region. As an example of the nonmagnetic conductive material constituting the tubular body 2, an austenitic nonmagnetic stainless steel can be exemplified. Note that it is not always necessary to make all the tubular bodies 2 constituting the tubular body group 2A non-magnetic, and at least those arranged in the outer peripheral region of the tubular body group may be made non-magnetic.
[0017]
The fluid supply header 3 includes a tube plate 11 that is held through one end side of the plurality of tube bodies 2 and a housing 14 with a fluid inlet 13 that is attached to the outer surface side of the tube plate 11. The housing 14 has a flange 14a for attaching to the tube plate 2 at one end, and a flange 14b for connecting to a fluid supply pipe (not shown) at the other end. The fluid discharge header 4 has a similar structure, and includes a tube plate 16 that is held through the other ends of the plurality of tube bodies 2 and a fluid outlet 18 that is attached to the outer surface side of the tube plate 16. The housing 19 is provided. The housing 19 is also provided with flanges 19a and 19b. As a method for inserting and fixing the tube body 2 to the tube plates 11 and 16, a known method such as screwing, tube expansion, fitting via a sealing material, brazing, or the like can be appropriately employed. By fixing the tube body 2 to the tube plates 11 and 16 in this way, the tube body group 2A, the fluid supply header 3 and the fluid discharge header 4 at both ends thereof can be integrated. If necessary, a connecting member for connecting the tube plates 11 and 16 on both sides may be provided to reinforce them. As long as the material of the members constituting the fluid supply header 3 and the fluid discharge header 4 has the necessary corrosion resistance, heat resistance, and strength, the electrical characteristics are not limited. That is, an induced current flows through the tube 2, but by arranging the induction coil 6 so that a magnetic flux is generated in the tube axis direction, the induced current only flows in the circumferential direction of the tube, Since there is almost no flow toward both ends of the tube 2, there is no need to make the tube plates 11 and 16 insulative or to dispose an insulating material between the tube plate and the tube body 2. Therefore, general-purpose materials such as carbon steel, stainless steel, and alloy steel can be used for the members constituting the fluid supply means 3 and the fluid discharge means 4.
[0018]
The first heat insulating material 5 arranged outside the tube group 2A also serves to prevent the induction coil 6 from being abnormally heated due to heat radiation from the tube body 2 that has been induction-heated. In the embodiment, the first heat insulating material 5 has a function of supporting the induction coil 6 and insulating from the inner tubular body 2. For this reason, the 1st heat insulating material 5 uses the cylindrical thing with moderate intensity | strength and insulation, for example, the nonwoven fabric pipe of inorganic fibers, such as an alumina fiber.
[0019]
The induction coil 6 is for inductively heating the tube group 2A, and is arranged to cover almost the entire length outside the tube group 2A. In this embodiment, the induction coil 6 is constituted by winding a flexible conductive wire, for example, a litz wire, around the outer circumference of the cylindrical first heat insulating material 5 in a spiral shape. By adopting this configuration, the induction coil 6 can be formed easily and inexpensively. In addition, when the electric current which flows through the induction coil 6 is large, or when the heating temperature of the fluid is very high, it is preferable to add cooling means such as water cooling to the induction coil 6. The water cooling can be performed, for example, by forming the induction coil with a copper tube and passing cooling water through the tube.
[0020]
The second heat insulating material 7 is provided together with the first heat insulating material 5 in order to prevent heat dissipation and increase thermal efficiency, and the thickness is determined so as to exhibit necessary heat insulating performance.
[0021]
Next, the heating operation by the fluid heating apparatus having the above configuration will be described. A fluid to be heated, for example, water vapor, is supplied from the fluid inlet 13, and an alternating current having an appropriate frequency is supplied to the induction coil 6 in a state where the fluid flows in the plurality of pipe bodies 2. By this energization, an alternating magnetic field is generated inside the induction coil 6, and an induced current is generated in each internal tube 2 to generate heat. At this time, as described above, since the tube bodies 2 are separated from each other, no induced current circulating in the outer circumferential portion of the tube body group 2A is generated, and the tube body 2 is non-magnetic. To the center of the tube group 2A, the alternating magnetic field enters the tube body 2A with a considerable strength, and combined with the fact that the tube is in a form suitable for induction heating, the induced current is efficiently and substantially uniform in each tube body 2. It generates and heats the tube 2 efficiently and evenly. Furthermore, since the fluid passes through a large number of small-diameter pipes 2, the contact area of the pipe, which is a heat generation source, with the fluid is much larger than when passing through a single large-diameter pipe. And rapid heat input is possible. Thus, the fluid can be heated and heated uniformly with high efficiency. Furthermore, as a feature of induction heating, it is possible to quickly heat the tube 2 and thus the fluid in the tube to a high temperature such as several hundred degrees. For example, using the tube 2 having a length of about 300 mm, C water vapor can be easily heated to about 500 ° C.
[0022]
In the above description, the case where heating is performed while flowing a fluid into the tube body 2 has been described. However, depending on the type of fluid, the tube body 2 is filled with the fluid and then heated with the fluid flow stopped. Then, a batch-type heating method may be employed in which the fluid is discharged from the tube body 2 when the desired temperature is reached.
[0023]
Moreover, in the said Example, although nothing is provided inside the pipe body 2, you may insert the appropriate baffle body for improving heat-transfer performance in the pipe body 2. FIG. FIG. 3 shows an example thereof, and a corrugated plate 23 in which a plate material is bent in a zigzag manner is inserted into the tube body 2. If the corrugated plate 23 is inserted, the fluid flowing in the tube body 2 is disturbed, so that the heat transfer coefficient between the inner surface of the tube body 2 and the fluid is greatly improved and the amount of heat transfer is increased. Can do. Further, since the corrugated plate 23 is also heated by heat conduction from the tube body 2, the surface thereof also acts as a heating area, and the amount of heat transfer can be increased from this point.
[0024]
【The invention's effect】
As described above, according to the present invention, a plurality of tubes made of a conductive material are arranged so as to be distributed in the depth direction from the outer periphery to the center in parallel with each other in a non-contact state. The tube body formed and formed at least in the outer peripheral region of the tube group is made of a non-magnetic material, and the fluid is passed through each tube body, and the induction coil is arranged so as to surround the tube group. In addition, by adopting a configuration in which a plurality of tubes are induction-heated and each of them functions as a uniform heat source, a large number of heat sources are distributed and arranged in a small space to ensure a high contact area with the fluid. The heating mode can be realized by using a general-purpose material and with a simple structure. That is, there is an effect that it is possible to provide a small-sized heating device at a low cost, capable of high-efficiency and uniform heating of the fluid and high-temperature heating.
[Brief description of the drawings]
1 is a schematic cross-sectional view taken along the central axis of a fluid heating apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view perpendicular to the central axis of the fluid heating apparatus shown in FIG. Is a schematic cross-sectional view showing a tube body and a corrugated plate inserted therein (b) is a schematic end view of the tube body shown in FIG.
DESCRIPTION OF SYMBOLS 1 Fluid heating apparatus 2A Tube group 2 Tube 3 Fluid supply header 4 Fluid discharge header 5 First heat insulating material 6 Inductive coil 7 Second heat insulating material 11, 16 Tube plate 14, 19 Housing 23 Corrugated plate

Claims (6)

A tube group consisting of a plurality of conductive material tubes arranged in parallel to each other, the tube group arranged so that the tubes are distributed also in the depth direction from the outer periphery to the center of the tube group And a fluid supply / discharge means for supplying and discharging a fluid to be heated only inside the plurality of tubes, and an induction coil arranged so as to surround the tube groups, the tube groups being mutually connected By arranging in a non-contact state, the alternating magnetic field generated by the induction coil can enter the central portion of the tube group, and an induced current flowing in the circumferential direction is generated in each tubular body including the central portion. A fluid heating apparatus characterized in that the attenuation of an alternating magnetic field to the center portion is reduced by forming a tubular body located at least in an outer peripheral region of the tubular body group with a nonmagnetic material.   The fluid heating device according to claim 1, wherein the plurality of tubes are arranged in a multiple ring shape.   The fluid heating device according to claim 1 or 2, wherein a first heat insulating material is disposed between the tube group and the induction coil, and a second heat insulating material is disposed outside the induction coil.   A fluid supply header, wherein the fluid supply / discharge means includes a tube plate held through one end side of the plurality of tube bodies, and a housing with a fluid inlet attached to an outer surface side of the tube plate; 2. A fluid discharge header comprising: a tube plate that is held by penetrating the other end of the tube body; and a housing with a fluid outlet that is attached to the outer surface of the tube plate. 2. The fluid heating apparatus according to 2 or 3.   5. The fluid heating apparatus according to claim 1, wherein a baffle for disturbing a fluid flowing through the plurality of pipes is disposed inside each of the plurality of pipes.   6. The fluid heating apparatus according to claim 1, wherein steam is supplied as a fluid and the steam is superheated.

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