JP2019129085A - Heating element, fluid heater, and heating element manufacturing method - Google Patents

Abstract

To provide a heating element, etc., with which it is possible to efficiently perform heating by a simple configuration while preventing foreign matters deriving from a heater from entering into fluid to be heated.SOLUTION: A heating element is constituted to include a cylindrical shaped outer tube 130, an inner tube 140 inserted into the cylindrical shaped outer tube at an inner diameter side, and a sheath heater S at least a part of which is sandwiched between an inner circumferential surface of the outer tube and an outer circumferential surface of the inner tube, at least one of the outer circumferential surface of the outer tube and the inner circumferential surface of the inner tube constituting a wall surface of a passage through which fluid to be heated passes.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a heating element used for heating various fluids such as gas and liquid, a fluid heater, and a method for manufacturing such a heating element, and in particular, foreign matter derived from a heater is mixed into a heated fluid. It is related with what can be heated efficiently, preventing.

The sheathed heater is an electric heater in which a heating wire (heating wire) such as a nichrome wire is accommodated in a metal heater pipe and an inorganic insulating powder is filled.
Because the sheathed heater is excellent in safety, reliability, economy, etc., and if the material of the heater pipe is a super heat resistant alloy such as a high nickel base alloy, it can be used up to a considerably high temperature, It is widely used as an industrial heater.
Further, such a sheathed heater is used as a heat source of a fluid heater which heats a fluid such as, for example, a gas such as air, inert gas and steam, various liquids, and a gas-liquid mixed fluid.

As a conventional technique related to a fluid heater using a sheathed heater as a heat source, for example, Patent Document 1 includes a sheathed heater in which a heater pipe is spirally wound inside a cylindrical heater through which a fluid passes. It is described that the heating fluid is heated in contact with the sheathed heater.
However, when such a fluid heater is used for, for example, process gas heating in a semiconductor manufacturing apparatus or drying air heating in an electronic component manufacturing process, peeling from the surface of a heater pipe or thermal expansion of a sheathed heater. If foreign matter (contamination) such as metal pieces caused by contact between the heater pipe and other parts such as a case or rubbing is mixed into the fluid to be heated, the product quality will be adversely affected. Is required.

As a conventional technique for preventing the sheathed heater and the fluid to be heated from coming into direct contact, for example, Patent Document 2 discloses that a heating medium passes through a heating medium heater used for recovering surplus power in a cogeneration system. There is a description in which a groove is formed on the surface of a cylindrical body, and a sheathed heater is bound with a band in a state where a part of the sheathed heater is disposed in the groove.
Further, in Patent Document 3, in a hot water supply apparatus that supplies hot water to a bathtub, a radiator, or the like, both the water flow pipe and the sheathed heater have an oval cross-sectional shape so that the flat surface portions are in contact with each other. A concentric double spiral wound is described.

JP 2004-69256 A JP 2004-37041 A JP 2006-52886 A

In the techniques described in Patent Documents 2 and 3, since the sheathed heater and the fluid to be heated do not directly contact with each other, it is possible to prevent the foreign matter derived from the sheathed heater from mixing in the fluid to be heated.
However, with the technique described in Patent Document 2, it is difficult to securely attach the heater pipe of the sheathed heater to the tubular body. For example, a gap is formed between the sheathed heater and the groove of the tubular body by springback or thermal expansion. When the is formed, there is a concern that the heating performance deteriorates.
Moreover, in the technique described in Patent Document 3, it is extremely difficult in practice to form the cross-sectional shapes of the water flow pipe and the sheathed heater into an oval shape so that the flat surface portion is securely adhered. is there.
Moreover, when the flow path through which the fluid to be heated passes is helical, the length of the flow path becomes longer and the pressure loss becomes larger, and it is difficult to efficiently heat a large amount of the fluid to be heated.
In view of the above-described problems, the problem of the present invention is that a heating element and a fluid heater that can efficiently perform heating while preventing foreign matters from the heater from being mixed into the heated fluid with a simple configuration, and It is providing a manufacturing method of such a heating element.

The present invention solves the above-mentioned problems by the following solutions.
The invention according to claim 1 includes an outer cylinder formed in a cylindrical shape, an inner cylinder formed in a cylindrical shape and inserted on an inner diameter side of the outer cylinder, at least a part of the inner peripheral surface of the outer cylinder, and the A sheathed heater sandwiched between the outer peripheral surface of the inner cylinder and at least one of the outer peripheral surface of the outer cylinder and the inner peripheral surface of the inner cylinder constitutes the wall surface of the flow path through which the fluid to be heated passes. It is a heating element characterized by the above.
According to this, since at least one of the outer cylinder and the inner cylinder is interposed between the sheathed heater and the fluid to be heated, the fluid to be heated and the heater pipe of the sheathed heater are not in direct contact with each other. It is possible to prevent foreign matters such as metal pieces peeled off from being mixed into the heated fluid.
In addition, the sheathed heater, the outer cylinder, and the inner cylinder are sandwiched, that is, held in a compressed state, so that they are not separated due to springback or thermal expansion, and the sheathed heater, the outer cylinder, and the inner cylinder are not separated. The close contact with the tube is maintained. For this reason, the heat transfer from the surface of the sheathed heater to the outer cylinder and the inner cylinder is good, and the surface of the outer cylinder and the inner cylinder contributes to the heat transfer, so that the fluid to be heated can be efficiently heated. In particular, since the outer cylinder functions as a means to suppress deformation of the sheath heater to the outer diameter side, separation of the sheath heater from the inner cylinder due to thermal expansion can be prevented.
Furthermore, by reinforcing and protecting the sheathed heater with the outer cylinder and the inner cylinder, the shape of the sheathed heater can be stably maintained, preventing the heater pipe from being broken, the heating wire from being broken, and the like, Reliability can be improved.

The invention according to claim 2 blocks the space between the inner peripheral surface of the outer cylinder and the outer peripheral surface of the inner cylinder to prevent the fluid to be heated from flowing into the space portion in which the sheathed heater is accommodated. It is a heat generating body according to claim 1, characterized by having a closed part.
According to this, it is possible to prevent the heated fluid from flowing into the space between the inner cylinder and the outer cylinder, and to reliably obtain the above-described effects.

The invention according to claim 3 is the heating element according to claim 1 or 2, wherein the sheathed heater is spirally wound around an outer peripheral surface of the inner cylinder.
According to this, a long sheathed heater can be arranged in the interval between the inner cylinder and the outer cylinder, the contact area between the inner cylinder, the outer cylinder and the sheathed heater is increased, heat transfer is promoted, and the heating performance is improved. It can be enhanced.

According to a fourth aspect of the present invention, a concavo-convex shape is formed along the surface of the sheathed heater at a location in contact with the heated fluid in at least one of the outer peripheral surface of the outer cylinder and the inner peripheral surface of the inner cylinder. The heating element according to claim 3.
According to this, by forming the concavo-convex shape, the contact area between the outer cylinder or the inner cylinder and the sheathed heater can be increased, and heat transfer from the sheathed heater to the outer cylinder and the inner cylinder can be improved.
In addition, the irregular shape is exposed as the wall surface of the flow path and comes into contact with the fluid to be heated, so that it becomes possible to form turbulence in the flow of the fluid to be heated, and the heating fluid is stirred to further improve the heating efficiency. Can.

The invention according to claim 5 further comprises a temperature sensor wound around the outer peripheral surface of the inner cylinder so as to substantially follow the sheathed heater. It is.
According to this, it is possible to arrange a temperature sensor in a narrow space inside the heating element without substantially interfering with the arrangement of the sheathed heater, and appropriately detect the temperature inside the heating element and use it for temperature control or the like. it can.

The invention according to claim 6 comprises the heating element according to any one of claims 1 to 5, and a housing which accommodates the heating element and in which a flow passage through which the fluid to be heated passes is formed. It is a fluid heater characterized by having.
According to this, it is possible to provide a fluid heater having substantially the same effect as the effect of each heating element described above.

The invention according to claim 7 is characterized in that the first flow path through which the fluid to be heated introduced into the housing flows in the axial direction of the outer cylinder along the outer peripheral surface of the outer cylinder, and the first flow path 7. The fluid according to claim 6, further comprising: a second flow path which is introduced and flows along the inner peripheral surface of the inner cylinder in the opposite direction to the inside of the first flow path. It is a heater.
According to this, the fluid to be heated can be effectively heated by heating the fluid to be heated on the outer peripheral surface and the inner peripheral surface of the heating element.
Further, the outlet temperature of the fluid to be heated can be improved by reheating the fluid to be heated, which is heated outside the heater, from the outside of the heater which is isolated from the outside air and has high thermal insulation.

The invention according to claim 8 includes an outer cylinder formed in a cylindrical shape, an inner cylinder formed in a cylindrical shape and inserted on the inner diameter side of the outer cylinder, and at least one of the inner cylinder and the inner cylinder A heating element manufacturing method comprising a sheathed heater sandwiched between an outer peripheral surface of a cylinder, wherein the sheathed heater is disposed between an inner peripheral surface of the outer cylinder and an inner peripheral surface of the inner cylinder. Thereafter, the inner cylinder is pressurized by a fluid pressure to expand the diameter of the inner cylinder.
According to this, the sheathed heater can be reliably held in the space between the inner cylinder and the outer cylinder by a simple manufacturing method.

The invention according to claim 9 is characterized in that the inner circumferential surface of the inner cylinder is pressurized with a fluid pressure to form a concavo-convex shape in which the shape of the sheathed heater is transferred to the inner cylinder. It is a manufacturing method of the heating element as described.
According to this, the outer cylinder retains the shape of the sheathed heater and prevents the deformation to the outer diameter side, thereby expanding the diameter of the inner cylinder, thereby plastically deforming the surface of the inner cylinder on the surface of the sheathed heater. It is possible to easily and accurately form an uneven shape that is in close contact.

The invention according to claim 10 includes an outer cylinder formed in a cylindrical shape, an inner cylinder formed in a cylindrical shape and inserted on the inner diameter side of the outer cylinder, and at least a part of the inner peripheral surface of the outer cylinder and the inner cylinder A heating element manufacturing method comprising a sheathed heater sandwiched between an outer peripheral surface of an inner cylinder, wherein the sheathed heater is disposed between an inner peripheral surface of the outer cylinder and an inner peripheral surface of the inner cylinder. Then, the outer peripheral surface of the outer cylinder is pressurized with a fluid pressure to reduce the diameter of the outer cylinder.
According to this, the sheathed heater can be reliably held in the space between the inner cylinder and the outer cylinder by a simple manufacturing method.

The invention according to claim 11 is characterized in that, by pressing the outer peripheral surface of the outer cylinder with a fluid pressure, a concavo-convex shape in which the shape of the sheathed heater is transferred to the outer cylinder is formed. Is a method of manufacturing a heating element.
According to this, the inner cylinder retains the shape of the sheathed heater, and the outer cylinder is reduced in diameter in a state in which the inner cylinder is prevented from being deformed to the inner diameter side, so that the surface of the outer cylinder is plastically deformed to be in close contact with the surface of the sheathed heater. Can be easily and accurately formed.

  As described above, according to the present invention, a heating element and a fluid heater capable of efficiently heating while preventing foreign matters derived from the heater from being mixed into the heated fluid with a simple configuration, and A method for manufacturing such a heating element can be provided.

It is a typical sectional view of a heating element which is a 1st embodiment of the present invention. It is a typical sectional view of a heating element which is a 2nd embodiment of the present invention. It is a typical sectional view of a fluid heater which is a 3rd embodiment of the present invention. It is a typical sectional view of a fluid heater which is comparative example 1 of the present invention. It is a typical sectional view of a fluid heater which is comparative example 2 of the present invention. FIG. 8 is a view schematically showing the flow of the fluid to be heated around the sheathed heater in the fluid heater of Comparative Example 1. It is a typical sectional view of a fluid heater which is a 4th embodiment of the present invention. It is a typical sectional view of a fluid heater which is a 5th embodiment of the present invention. It is a typical sectional view of a fluid heater which is a 6th embodiment of the present invention.

First Embodiment
Hereinafter, the heat generating body which is 1st Embodiment of this invention is demonstrated.
The heating element according to the first embodiment is provided as a heat source in a fluid heater that heats a fluid to be heated such as a gas, a liquid, or a gas-liquid mixture.
FIG. 1 is a schematic cross-sectional view of a heating element according to the first embodiment.
FIG. 1 shows a state cut along a plane including the central axes of the inner cylinder and the outer cylinder. (The same applies to FIGS. 2 to 5, 7, 8, and 9 described later)

As shown in FIG. 1, the heating element 1 includes an inner cylinder 10, an outer cylinder 20, end surface portions 30 and 40, a sheathed heater S, and the like.
The inner cylinder 10, the outer cylinder 20, and the end surfaces 30, 40 are formed of a heat-resistant metal material such as, for example, a stainless alloy.
The inner cylinder 10 and the outer cylinder 20 are formed in a cylindrical shape and arranged substantially concentrically.
The inner cylinder 10 is inserted on the inner diameter side of the outer cylinder 20.
A gap is formed between the outer peripheral surface of the inner cylinder 10 and the inner peripheral surface of the outer cylinder 20.
Both end portions of the inner cylinder 10 and the outer cylinder 20 are arranged so that their positions in the central axis direction are substantially coincident.

The end surface portions 30 and 40 are members (closing portions) which are provided at both end portions of the inner cylinder 10 and the outer cylinder 20 and substantially close the space between the inner cylinder 10 and the outer cylinder 20.
The end surface portions 30 and 40 are flat members formed along a plane orthogonal to the central axis of the inner cylinder 10 and the outer cylinder 20.
The end surface portions 30 and 40 are formed in a disk shape, and the outer peripheral edge portions are respectively welded to both end portions of the outer cylinder 20.
A circular opening is formed at the center of the end face portions 30 and 40, and the peripheral edge of the opening is welded to both end portions of the inner cylinder 10.

The sheathed heater S is an electric heater configured by accommodating nichrome wire inside a heater pipe and filling a gap with an insulating powder such as magnesia.
As a material for the heater pipe, for example, a nickel-based heat-resistant alloy containing iron, chromium, niobium, molybdenum or the like can be used.
The sheathed heater S is wound in a spiral shape concentric with the central axis of the inner cylinder 10 along the outer peripheral surface of the inner cylinder 10.
The sheathed heater S is sandwiched between the outer peripheral surface of the inner cylinder 10 and the inner peripheral surface of the outer cylinder 20 in a state where it is compressed (pressed) in the radial direction of the inner cylinder 10 and the outer cylinder 20.

For example, after the sheathed heater S is accommodated in the space between the outer peripheral surface of the inner cylinder 10 and the inner peripheral surface of the outer cylinder 20, a fluid pressure such as liquid (water as an example) is loaded on the inner peripheral surface of the inner cylinder 10. By expanding the diameter of the inner cylinder 10 by hydroforming, the sheathed heater S can be clamped (held in a compressed state) by a simple manufacturing method.
Alternatively, after the sheathed heater S is accommodated in the interval between the outer peripheral surface of the inner cylinder 10 and the inner peripheral surface of the outer cylinder 20, fluid pressure such as liquid (water as an example) is applied to the outer peripheral surface of the outer cylinder 20. It is also possible to hold the sheathed heater S by loading the outer cylinder 20 and reducing the diameter of the outer cylinder 20 by hydroforming.
Alternatively, swaging may be used instead of hydroforming using fluid pressure. For example, the diameter of the outer cylinder may be reduced by swaging to sandwich the sheathed heater S.

Such a heating element 1 can be used as a heat source of a fluid heater which heats various heated fluids such as a gas, a liquid, or a fluid in which gas and liquid are mixed.
The fluid heater has a flow path through which the fluid to be heated passes, and at least one of the outer peripheral surface of the outer cylinder 20 and the inner peripheral surface of the inner cylinder 10 of the heating element 1 directly contacts the heated fluid as a wall surface of the flow path. It can be configured.

According to the first embodiment described above, the following effects can be obtained.
(1) Since at least one of the inner cylinder 10 and the outer cylinder 20 is interposed between the sheathed heater S and the fluid to be heated, the fluid to be heated and the heater pipe of the sheathed heater S are not in direct contact with each other. It is possible to prevent foreign matters such as metal pieces caused by peeling from the heater pipe, contact between the heater pipe and other parts such as the case and the housing due to thermal expansion of the sheathed heater S, and rubbing, etc. from entering the heated fluid.
Further, since the sheathed heater S closely contacts the inner cylinder 10 and the outer cylinder 20, the heat transfer from the surface of the sheathed heater S to the inner cylinder 10 and the outer cylinder 20 is good. The surface contributes to heat transfer, so that the fluid to be heated can be efficiently heated.
Further, by reinforcing and protecting the sheathed heater S with the inner cylinder 10 and the outer cylinder 20, the shape of the sheathed heater S can be stably maintained, and the heater pipe can be prevented from being broken or the heating wire being disconnected. Durability and reliability can be improved.
(2) By closing the both end portions of the heating element 1 with the end face portions 30 and 40, the fluid to be heated is prevented from flowing into the space between the inner cylinder and the outer cylinder, and the above-described effects can be reliably obtained. it can.
(3) Since the sheathed heater S is spirally wound around the outer peripheral surface of the inner cylinder 10, a sufficiently long sheathed heater S can be disposed in the space between the inner cylinder 10 and the outer cylinder 20. The contact area between the cylinder 10 and the outer cylinder 20 and the sheathed heater S can be increased to promote heat transfer and enhance the heating performance.
(4) In a state where the spirally wound sheathed heater S is accommodated between the inner cylinder 10 and the outer cylinder 20, the inner cylinder 10 is expanded in diameter by hydraulic pressure, so that the sheathed heater can be manufactured by a simple manufacturing method. S can be securely held in the space between the inner cylinder 10 and the outer cylinder 20.

Second Embodiment
Next, the heat generating body which is 2nd Embodiment of this invention is demonstrated.
In the respective embodiments and comparative examples to be described below, the same reference numerals are given to portions substantially common to the previous embodiment and the description thereof is omitted, and the difference will be mainly described.
FIG. 2 is a schematic cross-sectional view of the heating element of the second embodiment.

As shown in FIG. 2, the heating element 1A has an open-type configuration in which the end faces 30, 40 are removed from the heating element 1 of the first embodiment.
Also in the second embodiment, the effects of the first embodiment described above are set by setting the device configuration of the fluid heater so that the fluid to be heated does not directly flow into the gap between the inner cylinder 10 and the outer cylinder 20. A substantially similar effect can be obtained.

Third Embodiment
Next, a fluid heater which is a third embodiment of the present invention will be described.
The fluid heater according to the third embodiment is used to heat process gas, heating air, nitrogen gas and the like used in, for example, a process of manufacturing a flat panel display (FPD) such as a semiconductor or an organic EL display. (Same in the fourth and fifth embodiments)

FIG. 3 is a schematic cross-sectional view of the fluid heater according to the third embodiment.
As shown in FIG. 3, the fluid heater 50 is obtained by housing a heating element 1 substantially similar to that of the first embodiment in a housing 51 described below.
The housing 51 is a container-like member that accommodates the heating element 1 and through which the fluid to be heated flows.
The housing 51 includes a cylindrical portion 52, an inlet portion 53, an outlet portion 54, an intermediate cylinder 55, and the like.

The cylindrical portion 52 is a main body portion of the housing 51 and is formed substantially in a cylindrical shape.
The inlet 53 and the outlet 54 are formed by reducing the diameter of one end and the other end of the cylindrical portion 52.
The inlet portion 53 is a portion into which the fluid to be heated is introduced.
The outlet portion 54 is a portion where the heated fluid after heating is discharged.
The intermediate cylinder 55 is a cylindrical member disposed on the inner diameter side of the cylindrical portion 52 so as to be substantially concentric with the cylindrical portion 52.

In the heat generating element 1, the inner peripheral surface of the inner cylinder 10 is opposed to the outer peripheral surface of the intermediate cylinder 55 with a space, and the outer peripheral surface of the outer cylinder 20 is opposed to the inner peripheral surface of the cylindrical portion 52 with a space. , And is disposed inside the cylindrical portion 52.
These intervals serve as channels through which the fluid to be heated flows.
The fluid to be heated is introduced into the interior of the cylindrical portion 52 from the inlet 53 as shown by the arrow in FIG. 3, and the distance between the inner peripheral surface of the inner cylinder 10 and the outer peripheral surface of the intermediate cylinder 55 Is heated while passing through an interval between the outer peripheral surface of the cylindrical portion 52 and the inner peripheral surface of the cylindrical portion 52, heated to a predetermined target heating temperature, and then discharged from the outlet portion 54.

Hereinafter, the effects of the above-described third embodiment will be described in comparison with Comparative Examples 1 and 2 of the present invention described below.
Comparative Example 1
FIG. 4 is a schematic cross-sectional view of a fluid heater that is Comparative Example 1 of the present invention.
As shown in FIG. 4, a fluid heater 50 </ b> A of Comparative Example 1 includes a sheathed heater S wound in a spiral shape instead of the heating element 1 in a housing 50 that is substantially the same as that of the third embodiment. It is arranged alone.
In the fluid heater 50A of Comparative Example 1, the fluid to be heated is brought into direct contact with the sheathed heater S to be heated.

Comparative Example 2
FIG. 5 is a schematic cross-sectional view of a fluid heater that is Comparative Example 2 of the present invention.
As shown in FIG. 5, the fluid heater 60 of Comparative Example 2 includes a sheathed heater S in which a heater pipe is arranged in a cylindrical axis direction and a radial direction inside a cylindrical housing 61. It is.
The heated fluid is introduced from one end of the housing 61, heated in direct contact with the sheathed heater S, and then discharged from the other end of the housing 61.

The characteristics of the third embodiment, the comparative example 1 and the comparative example 2 described above will be described below.
In the configuration of Comparative Example 2, the flow passage cross-sectional area of the fluid to be heated is large, so the flow velocity of the fluid to be heated is slower than in the third embodiment and Comparative Example 1.
For this reason, since the heat transfer rate from the sheathed heater S to the fluid to be heated is deteriorated, the sheathed heater S itself tends to be at a high temperature, and there is a concern about durability and reliability.

On the other hand, when the flow path cross-sectional area is reduced using the intermediate cylinder 55 as in Comparative Example 1, the flow rate of the fluid to be heated can be improved. The heat transfer rate from the fluid to the fluid to be heated can be improved.
In addition, the temperature of the sheathed heater S can also be made lower than that of Comparative Example 2, which is advantageous in terms of durability and reliability.
However, in both Comparative Example 1 and Comparative Example 2, since the fluid to be heated is in direct contact with the heater pipe of the sheathed heater S, foreign matter such as metal pieces (particles) peeled off from the surface of the heater pipe becomes the fluid to be heated. There is a concern that it mixes and becomes contamination.

Further, even if the fluid to be heated is in direct contact with the sheathed heater S as in Comparative Example 1, it is not necessarily advantageous in terms of the heat transfer coefficient to the fluid to be heated. This point will be described below.
FIG. 6 is a view schematically showing the flow of the fluid to be heated around the sheathed heater in the fluid heater of Comparative Example 1. As shown in FIG.
As shown in FIG. 6, when a plurality of heater pipes of the sheathed heater S are arranged along the flow F of the fluid to be heated, a vortex T is generated on the downstream side of each heater pipe, and a stagnation region is formed. Be done.
For this reason, even if the sheathed heater S is in direct contact with the fluid to be heated, the region R (illustrated by a bold broken line in FIG. 6) that effectively contributes to heating of the fluid to be heated is a portion other than the stagnation region. Therefore, only about 1/2 of the total surface area of the heater pipe functions as the effective heat transfer area.

  On the other hand, in the third embodiment, since the heater pipe of the sheathed heater S is in close contact with the inner cylinder 10 and the outer cylinder 20 of the heating element 1, the heat generated by the heater pipe is the inner cylinder 10 and the outer cylinder 20. Since the substantially entire surface of the inner cylinder 10 and the outer cylinder 20 contributes to the heating of the heated fluid, a heat transfer effective area comparable to that of the comparative example 1 can be ensured.

Further, as in Comparative Examples 1 and 2, when the sheathed heater S is in direct contact with the fluid to be heated, the self-holding power of the shape is poor when using a relatively small diameter sheathed heater, and other structures Need to be supported and fixed.
Further, when fluid heating is performed with the small-sized sheathed heater S, there is a concern that a load is applied due to vibration or the like caused by the flow of the fluid to be heated, and the sheathed heater S may be deformed or a failure such as disconnection may occur. Ru.
On the other hand, even if the sheathed heater S has a relatively large diameter, if the flow velocity of the fluid to be heated is high and the external force applied to the sheathed heater S is strong, it is necessary to similarly support and fix it with other structures.

On the other hand, according to the third embodiment, the sheathed heater S can be reinforced and protected by sandwiching the sheathed heater S between the inner cylinder 10 and the outer cylinder 20, and the sheathed heater S can be protected without any other structure. The shape can be maintained to prevent deformation and damage.
Furthermore, the electrical insulation of the sheathed heater S and the configuration of the heating element 1 are facilitated.

Fourth Embodiment
Next, a fluid heater which is a fourth embodiment of the present invention will be described.
FIG. 7 is a schematic cross-sectional view of the fluid heater according to the fourth embodiment.
As shown in FIG. 7, the fluid heater 100 includes a first cylinder 110, a second cylinder 120, a third cylinder 130, a fourth cylinder 140, an inlet cylinder 150, a sheathed heater S, and the like.

The first cylinder 110, the second cylinder 120, the third cylinder 130, the fourth cylinder 140, and the inlet cylinder 150 are each formed in a substantially cylindrical shape and are arranged so as to be substantially concentric.
The first cylinder 110 is a member constituting an outer surface portion of the main body portion of the fluid heater 100.
End surface portions 111 and 112 are provided at both ends of the first tube 110, respectively.
The end surface portions 111 and 112 are disk-shaped and flat-plate members that substantially close both end portions of the first tube 110.
A circular opening substantially concentric with the central axis of the first tube 110 is formed at the center of the end surface portions 111 and 112.
The downstream end of the inlet tube 150 is connected to the peripheral edge of the opening of the end surface portion 111.
The inlet cylinder 150 is a cylindrical member that protrudes from the end surface portion 111 and into which a fluid to be heated is introduced.
The peripheral edge portion of the opening of the end surface portion 112 is joined to the outer peripheral surface of the third cylinder 130.

The second cylinder 120 is inserted on the inner diameter side of the first cylinder 110.
The outer peripheral surface of the second cylinder 120 is disposed to face the inner peripheral surface of the first cylinder 110 with a gap in the radial direction.
An end surface portion 121 and a support member 122 are provided at the end portion of the second cylinder 120 on the end surface portion 111 side (left side in FIG. 7).
The end surface portion 121 is a disk-shaped and flat member that closes the end of the second cylinder 120.
The end surface portion 121 is disposed to face the end surface portion 111 and the second cylinder 120 at intervals in the central axis direction.

The support member 122 is a member that supports the second cylinder 120 inside the first cylinder 110.
The support member 122 is formed in, for example, a flat plate shape that extends along the radial direction of the first cylinder.
The end edge of the support member 122 on the second cylinder 120 side is joined to the outer peripheral surface in the vicinity of the end portion on the end surface 121 side of the second cylinder 120 and the end surface 121.
The end edge of the support member 122 on the first cylinder 110 side is joined to the inner circumferential surface in the vicinity of the end on the end surface 111 side of the first cylinder 110 and the end surface 111.
The end of the second cylinder 120 on the side of the end surface portion 112 is disposed in an open state so as to be opposed to the end surface portion 111 with a space in the central axis direction of the second tube 120, and the inside of the first tube 110. It is in communication.
The first cylinder 110 and the second cylinder 120 function as a housing that accommodates the heat generating element composed of the third cylinder 130 and the fourth cylinder 140.

The third cylinder 130 is inserted on the inner diameter side of the second cylinder 120.
The outer peripheral surface of the third cylinder 130 is disposed so as to face the inner peripheral surface of the second cylinder 120 at an interval in the radial direction.
An end surface portion 131 is provided at an end portion of the third cylinder 130 on the end surface portion 111 side.
The end surface portion 131 is a disk-like and flat plate-like member that closes an end portion of the third cylinder 130 on the side of the end surface portion 111.
The end surface portion 131 is disposed to face the end surface portion 121 and the third cylinder 130 at intervals in the central axis direction.
A circular opening substantially concentric with the central axis of the third cylinder 130 is formed at the central portion of the end surface portion 131.
The end of the fourth cylinder 140 on the side of the end face 111 is connected to the opening of the end face 131.
The end surface portion 131 prevents the heated fluid from flowing between the inner peripheral surface of the third cylinder 130 and the outer peripheral surface of the fourth cylinder 140.
An outer peripheral surface portion at an end portion of the third cylinder 130 opposite to the end surface portion 131 side is joined to the inner peripheral edge portion of the opening of the end surface portion 112.

The main part of the fourth cylinder 140 is inserted into the inner diameter side of the third cylinder 130, and the end opposite to the inlet cylinder 150 side protrudes from the end surface part 112 and functions as an outlet cylinder of the fluid heater 100. Do.
The outer peripheral surface of the fourth cylinder 140 is disposed so as to face the inner peripheral surface of the third cylinder 130 at an interval in the radial direction.
The outer peripheral surface portion at the end portion on the end surface portion 111 side of the fourth cylinder 140 is joined to the inner peripheral edge portion of the opening of the end surface portion 131.
Each member demonstrated above is formed, for example with metal materials, such as stainless steel, and is joined by welding.

In the present embodiment, the third cylinder 130 functions as an outer cylinder of the heating element, and the fourth cylinder 140 functions as an inner cylinder of the heating element.
The sheathed heater S is bent in a U shape at an intermediate position in the longitudinal direction of the heater pipe, and in a state where the two heater pipes are bundled, these are formed in a double spiral shape so that the fourth cylinder 140 is It is wound around and inside the third tube 130.
Both ends of the sheathed heater S (ends on the side opposite to the bent portion after bending) are drawn out from the opening of the end face portion 112, and the nichrome wire is connected to a power supply device (not shown).

At the time of manufacturing the fluid heater 100, the sheathed heater S is inserted into the inner diameter side of the third cylinder 130 while being wound around the outer peripheral surface of the fourth cylinder 140.
At this time, between the sheathed heater S and the inner circumferential surface of the third cylinder 130, a gap which is inevitably provided to enable insertion is provided.
Thereafter, the fourth cylinder 140 is expanded in diameter by applying fluid pressure (for example, hydraulic pressure such as water pressure) to the inner peripheral surface of the fourth cylinder 140.
By expanding the diameter of the fourth cylinder 140, the sheathed heater S is sandwiched in a compressed state between the outer peripheral surface of the fourth cylinder 140 and the inner peripheral surface of the third cylinder 130. Close contact with the cylinder 140 and the third cylinder 130.
At this time, although the third cylinder 130 is pressed against the inner peripheral surface by the sheathed heater S, the material, the plate thickness, and the like are set so as not to substantially expand and deform by the input.

The fourth cylinder 140 is expanded in diameter by fluid pressure, and the uneven shape 141 to which the surface shape of the heater pipe of the sheathed heater S is transferred is formed.
The concavo-convex shape 141 has a bellows-like shape in which grooves are spirally formed along the interval between the heater pipes of the sheathed heater S.
The material, plate thickness, and the like of the fourth cylinder 140 are set so that the concave-convex shape 141 can be formed (hydroforming) at the time of expanding the diameter by fluid pressure.

Next, the flow of the fluid to be heated in the fluid heater 100 of the fourth embodiment will be described.
As illustrated by the arrows in FIG. 7, the fluid to be heated is first introduced into the interior of the first cylinder 110 from the inlet cylinder 150.
Thereafter, the fluid to be heated flows from the end surface 111 to the end surface 112 between the inner peripheral surface of the first cylinder 110 and the outer peripheral surface of the second cylinder 120.
At this time, the fluid to be heated is preheated by heat transfer from the second cylinder 120, but since it is not in direct contact with the heating elements (the third cylinder 130 and the fourth cylinder 140), it does not become excessively high temperature. .
Here, the fluid to be heated prevents the outer surface of the first cylinder 110 from becoming excessively high temperature, suppresses heat radiation to the surroundings, improves efficiency, and is disposed around the fluid heater 100. Demonstrates the function of preventing heat damage to workers, etc. and burns of workers.

The fluid to be heated that has reached the end portion on the end surface portion 112 side is reversed and flows between the inner peripheral surface of the second tube 120 and the outer peripheral surface of the third tube 130 from the end surface portion 112 side to the end surface portion 121 side.
The third cylinder 130 is in close contact with the heater pipe of the sheathed heater S and is heated to a high temperature, and the fluid to be heated is heated by heat transfer from the third cylinder 130.
At this time, since the region between the first cylinder 110 and the second cylinder 120 functions as a heat insulating layer, cooling by the outside air of the heated fluid flowing between the second cylinder 120 and the third cylinder 130 is suppressed. Ru.

The fluid to be heated that has reached the end on the end surface 121 side is reversed again, flows inside the fourth tube 140 toward the end surface 112, and is discharged from the end of the fourth tube 140 to the outside.
The fourth cylinder 140 is in close contact with the heater pipe of the sheathed heater S and is heated to a high temperature, and the fluid to be heated is further heated by the heat transfer from the fourth cylinder.
In addition, since the fourth cylinder 140 has an uneven shape 141, the surface area increases with respect to a simple cylindrical inner surface shape, and the development of the turbulent flow of the heated fluid that flows near the inner peripheral surface of the fourth cylinder 140 is promoted. Then, the heat transfer rate is improved by stirring the heated fluid.

According to the fourth embodiment described above, the following effects can be obtained in addition to the effects substantially similar to the effects of the first to third embodiments.
(1) By heating the heated fluid on the outer peripheral surface of the third cylinder 130 and the inner peripheral surface of the fourth cylinder 140 constituting the heating element, the heated fluid can be effectively heated.
Further, the outlet temperature of the heated fluid can be improved by heating the heated fluid heated outside the third cylinder 130 again inside the fourth cylinder 140 having higher heat insulation from the outside. .
(2) The contact area between the fourth cylinder 140 and the sheathed heater S is increased by forming the bellows-like uneven shape 141 on the fourth cylinder 140 that functions as the inner cylinder of the heating element. Heat transfer to the four cylinders 140 can be improved.
In addition, the irregular shape 141 is exposed as the wall surface of the flow path and comes into contact with the fluid to be heated, so that it becomes possible to form a turbulence in the flow of the fluid to be heated. The heating efficiency can be further improved.
(3) The surface of the fourth cylinder 140 is plastically deformed by expanding the diameter of the fourth cylinder 140 while the third cylinder 130 maintains the shape of the sheathed heater S and prevents deformation to the outer diameter side. The surface shape of the sheathed heater S is transferred, and the concavo-convex shape 141 that adheres closely to the surface of the sheathed heater S can be formed easily and accurately.
(4) The fluid heater is configured such that four cylindrical bodies (first cylinder 110 to fourth cylinder 140) are arranged concentrically, and the heated fluid flows sequentially from the outer diameter side to the inner diameter side. The surface temperature of 100 can be made relatively low, and thermal damage to peripheral parts, operator burns, and the like can be prevented.
Moreover, since a heat insulating material becomes unnecessary, generation | occurrence | production of the contamination resulting from a heat insulating material can be prevented.

Fifth Embodiment
Next, a fluid heater which is a fifth embodiment of the present invention will be described.
FIG. 8 is a schematic cross-sectional view of the fluid heater according to the fifth embodiment.
The fluid heater 100A of the fifth embodiment includes a thermocouple TC, which is a temperature sensor, in a third cylinder 130 together with a sheathed heater S that is bent in a U shape and bundles two heater pipes. It is characterized in that it is spirally wound between the circumferential surface and the outer circumferential surface of the fourth cylinder 140, and the other configuration is substantially the same as that of the fluid heater 100 of the fourth embodiment.
That is, the two heater pipes of the sheathed heater S and the thermocouple TC are wound in a triple spiral shape.
According to the fifth embodiment described above, in addition to the effect substantially similar to the effect of the above-described fourth embodiment, in the narrow space inside the heating element composed of the third cylinder 130 and the fourth cylinder 140. The thermocouple TC can be disposed without substantially disturbing the disposition of the sheathed heater S, and the temperature inside the heating element can be appropriately detected.

Sixth Embodiment
Next, a fluid heater according to a sixth embodiment of the present invention will be described.
FIG. 9 is a schematic cross-sectional view of the fluid heater according to the sixth embodiment.
The fluid heater 60A of the sixth embodiment accommodates the heating element 1 of the first embodiment on the inner diameter side of a housing 61 substantially similar to that of the second comparative example.
The housing 61 is formed in a cylindrical shape having a substantially constant outer diameter and an inner diameter over the entire length.
An intermediate cylinder 62 substantially similar to the intermediate cylinder 55 of the third embodiment is provided on the inner diameter side of the heating element 1.
Also in the sixth embodiment described above, substantially the same effects as the effects of the third embodiment described above can be obtained.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, which are also within the technical scope of the present invention.
(1) The configurations of the heating element and the fluid heater can be appropriately changed without being limited to the above-described embodiment.
For example, in the fourth and fifth embodiments, the diameter of the fourth cylinder 140 that functions as the inner cylinder of the heating element is expanded by hydroforming, and the concave and convex shape 141 is formed in the fourth cylinder 140. Alternatively, or together with this, the outer cylinder may be reduced in diameter by a fluid force or a mechanical force such as a swager, and an uneven shape may be formed on the outer cylinder.
Further, the configuration of the housing of the fluid heater, the arrangement of the heating elements, the number of the heating elements to be mounted, and the like can be appropriately changed.
(2) The fluid heater of the present invention is not limited to heating of process gas, heating air, etc. used in the manufacturing process of flat panel displays (FPD) such as semiconductors and organic EL displays as described in the embodiments. It can also be used for other applications.
For example, heating of various gases such as air used as a heat medium for moisture removal and drying, heat treatment furnace atmosphere gas heating, gas heating for analyzers, various inert gas heating, various liquid heating, generation of superheated steam, heating It can be used for burning of food by gas, reduction of gas consumption utilizing volume expansion by heating inert gas, and the like.

1 Heating element (first embodiment) 1A Heating element (second embodiment)
DESCRIPTION OF SYMBOLS 10 inner cylinder 20 outer cylinder 30 end surface part 40 end surface part S sheathed heater 50 fluid heater (3rd Embodiment)
DESCRIPTION OF SYMBOLS 50A fluid heater (comparative example 1) 51 housing 52 cylindrical part 53 inlet part 54 exit part 55 intermediate cylinder 60 fluid heater (comparative example 2) 60A fluid heater (sixth embodiment)
61 Housing 62 Intermediate cylinder T Eddy current R Area to be effective heat transfer area 100 Fluid heater (fourth embodiment) 100A Fluid heater (fifth embodiment)
DESCRIPTION OF SYMBOLS 110 1st cylinder 111 End surface part 112 End surface part 120 2nd cylinder 121 End surface part 122 Support member 130 3rd cylinder 131 End surface part 140 4th cylinder 141 Uneven shape 150 Inlet cylinder TC Thermocouple

Claims (11)

An outer cylinder formed in a tubular shape,
An inner cylinder formed in a cylindrical shape and inserted into the inner diameter side of the outer cylinder;
A sheathed heater at least a part of which is sandwiched between the inner peripheral surface of the outer cylinder and the outer peripheral surface of the inner cylinder;
A heating element, wherein at least one of the outer peripheral surface of the outer cylinder and the inner peripheral surface of the inner cylinder constitutes a wall surface of a flow passage through which the fluid to be heated passes. It has a blocking portion that blocks between the inner peripheral surface of the outer cylinder and the outer peripheral surface of the inner cylinder and prevents the heated fluid from flowing into the space in which the sheathed heater is accommodated. The heating element according to claim 1. The heating element according to claim 1 or 2, wherein the sheathed heater is spirally wound around an outer peripheral surface of the inner cylinder. The uneven | corrugated shape along the surface of the said sheathed heater was formed in the location which contacts the said to-be-heated fluid in at least one of the outer peripheral surface of the said outer cylinder, and the inner peripheral surface of the said inner cylinder. The heating element described in. The heating element according to claim 3, further comprising a temperature sensor wound around the outer peripheral surface of the inner cylinder so as to substantially follow the sheathed heater. The heating element according to any one of claims 1 to 5,
A fluid heater, comprising: a housing that accommodates the heating element and is formed with a flow passage through which a fluid to be heated passes. A first flow path in which the heated fluid introduced into the housing flows in the axial direction of the outer cylinder along the outer peripheral surface of the outer cylinder;
And a second flow path which flows in the opposite direction to the inside of the first flow path along the inner peripheral surface of the inner cylinder, into which the fluid to be heated which has passed through the first flow path is introduced. The fluid heater according to claim 6. An outer cylinder formed in a tubular shape,
An inner cylinder formed in a cylindrical shape and inserted into the inner diameter side of the outer cylinder;
At least one is a manufacturing method of a heating element comprising: a sheathed heater sandwiched between an inner peripheral surface of the outer cylinder and an outer peripheral surface of the inner cylinder,
After the sheathed heater is disposed between the inner peripheral surface of the outer cylinder and the inner peripheral surface of the inner cylinder, the inner cylinder is expanded by pressurizing the inner peripheral surface of the inner cylinder with fluid pressure. And a method of manufacturing a heating element. The method for manufacturing a heating element according to claim 8, wherein the inner peripheral surface of the inner cylinder is pressurized by fluid pressure to form an uneven shape in which the shape of the sheathed heater is transferred to the inner cylinder. An outer cylinder formed in a tubular shape,
An inner cylinder formed in a cylindrical shape and inserted into the inner diameter side of the outer cylinder;
A heating element manufacturing method comprising: a sheathed heater at least partially sandwiched between an inner peripheral surface of the outer cylinder and an outer peripheral surface of the inner cylinder,
After arranging the sheathed heater between the inner peripheral surface of the outer cylinder and the inner peripheral surface of the inner cylinder, the outer cylinder is pressurized by fluid pressure to reduce the diameter of the outer cylinder. Method of producing a heating element. The manufacturing method of the heat generating body according to claim 10, wherein the uneven shape having the shape of the sheathed heater transferred to the outer cylinder is formed by pressurizing the outer peripheral surface of the outer cylinder with a fluid pressure.

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