JP7269624B2 - FLUID HEATER AND METHOD FOR MANUFACTURING FLUID HEATER - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fluid heater having a sheathed heater provided inside a flow path through which a fluid to be heated flows, and a method of manufacturing such a fluid heater.

A sheathed heater is a resistance electric heater configured by housing a heating wire inside a sheath, which is a cylindrical member, and filling it with insulating powder such as magnesia.
The sheathed heater has excellent electrical insulation and can safely heat the fluid to be heated, and can also be used at high temperatures by appropriately selecting the material.
Further, by bending the sheath, it is possible to form the heat generating portion into an arbitrary shape according to the installation space.

As a prior art related to a fluid heater that heats a fluid to be heated by a sheathed heater, for example, Patent Document 1 discloses a gas heater in which a spirally wound sheathed heater is accommodated inside a cylindrical body through which a fluid to be heated flows. A heater is described.

JP 2007-101048 A

When the sheathed heater is arranged in the middle portion of the flow path through which the fluid to be heated flows, with the terminal portion protruding outside the cross section of the flow path, for example, half of the cylindrical member forming the flow path in the circumferential direction It has been proposed to provide a sheathed heater insertion port on a box projecting to the outer diameter side of the cylindrical body while notching the portion. (See Comparative Example 1 of the present invention described later)
However, in such a configuration, the cross-sectional area of the flow passage changes greatly at the location where the sheathed heater insertion port is provided, and the fluid to be heated avoids the sheathed heater and passes through the sheathed heater insertion port. There is a concern that the heating performance will deteriorate.
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a fluid heater and a method for manufacturing the fluid heater in which a change in the cross section of the flow path is suppressed with a simple structure.

The present invention solves the problems described above by means of the following solutions.
The invention according to claim 1 comprises a cylindrical flow path member through which a fluid to be heated flows, and a sheath formed in a cylindrical shape containing a heating wire and an insulating powder, wherein the flow path member and a sheathed heater having an intermediate portion disposed on the inner diameter side of the flow path member and an end portion disposed projecting to the outside of the flow path member, wherein the flow path member is divided in the cylinder axis direction. a protruding tubular portion formed by connecting a first member and a second member which are formed by connecting the first member and protruding outward from the first member and into which the end portion of the sheathed heater is inserted; a part of the end portion joined to the second member is arranged on the side opposite to the second member side with respect to the other part so that the sheathed heater can be inserted along the longitudinal direction of the protruding tubular portion; The channel member has a recessed portion, and the flow path member maintains a basic cross-sectional shape from an upstream region of the sheathed heater to a downstream region of the sheathed heater. The fluid heater is characterized in that the end portion of the heater is in contact with the outer peripheral surface thereof .
According to this, the channel member is divided into the first member and the second member in the axial direction, and the shape of the dividing line is set so that the sheathed heater can be inserted along the longitudinal direction of the protruding tubular portion. , the sheathed heater can be inserted into the inner diameter side of the first member before joining the first member and the second member, and then the first member and the second member can be joined.
As a result, it is possible to easily obtain a fluid heater incorporating a sheathed heater while preventing a change in cross section of the flow path in the flow path member.
Therefore, the flow of the fluid to be heated avoiding the sheathed heater is suppressed, the heating efficiency is improved, and the basic cross-sectional shape of the flow path member is maintained. It is possible to prevent problems caused by the provision of structural bodies having different shapes.

The invention according to claim 2 is characterized in that a joint portion where the first member and the second member are joined is arranged along a plane inclined with respect to a cylinder axis direction of the channel member. The fluid heating according to claim 1.
According to this, since the dividing line between the first member and the second member becomes a straight line when viewed from a predetermined direction, it is easy to form a butting portion between the first member and the second member. is.
In addition, since no corner portion or the like is formed on the parting line, joining is facilitated, and stress concentration can be prevented to ensure durability and reliability.
Furthermore, since the parting line does not intersect the circumferential direction of the channel member, even if the pressure of the fluid to be heated is high and a significant tensile stress is applied in the circumferential direction of the channel member, the parting line It is possible to suppress damage and ensure pressure resistance, durability, and reliability.

In the invention according to claim 3, the first member and the second member are joined by butt welding, and the inner peripheral surface of the flow path member at the joint between the first member and the second member has 3. The fluid heater according to claim 1, wherein a protective member is provided along the groove to prevent the weld bead from protruding toward the inner diameter side.
According to this, it is possible to prevent the welding bead from projecting to the inner diameter side of the flow path member and damaging the sheathed heater.

According to a fourth aspect of the present invention, there is provided a cylindrical flow path member through which a fluid to be heated flows, and a sheath formed in a cylindrical shape containing a heating wire and an insulating powder, wherein the flow path member a sheathed heater having an intermediate portion arranged on the inner diameter side of the flow channel member and an end portion arranged to protrude outside of the flow channel member, wherein the flow channel member extends in the cylinder axis direction a first member and a second member which are divided into two parts, and a protruding cylindrical part is attached to the first member so as to protrude outward and into which the end of the sheathed heater is inserted; and inserting the end portion of the sheathed heater along the longitudinal direction of the projecting cylindrical portion so that the heat generating portion is inside the first member when viewed from the cylindrical axis direction of the flow path member. and a third step of joining the first member and the second member in abutted state , wherein the flow path member is an upstream region of the sheathed heater. A fluid heater characterized in that a basic cross-sectional shape is maintained over a region downstream of the sheathed heater, and the inner peripheral surface of the protruding cylindrical portion and the outer peripheral surface of the end portion of the sheathed heater are in contact with each other. manufacturing method.
In the invention according to claim 5, in the third step, the first member and the second member are butt-welded, and on the inner diameter side of the joint portion between the first member and the second member, 5. The method of manufacturing a fluid heater according to claim 4, wherein the method is performed in a state in which a protective member is provided to prevent the weld bead from protruding.
In each of these inventions, substantially the same effects as those of the invention relating to the fluid heater described above can be obtained.

As described above, according to the present invention, it is possible to provide a fluid heater and a method for manufacturing the fluid heater that suppresses changes in the cross section of the flow path with a simple structure.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of 1st Embodiment of the fluid heater to which this invention is applied. 4 is an enlarged cross-sectional view of a joint portion between a first member and a second member of the flow path member in the fluid heater of the first embodiment; FIG. FIG. 10 is a diagram showing a process of dividing the flow path member in the manufacturing process of the fluid heater of the first embodiment; It is a manufacturing process of the fluid heater of 1st Embodiment, Comprising: It is a figure which shows the attachment process of a sheathed heater. It is a manufacturing process of the fluid heater of 1st Embodiment, Comprising: It is a figure which shows the attachment process of the 2nd member to the 1st member. FIG. 2 is a cross-sectional view of a fluid heater that is Comparative Example 1 of the present invention; FIG. 4 is a cross-sectional view of a fluid heater that is Comparative Example 2 of the present invention; FIG. 4 is a cross-sectional view of a second embodiment of a fluid heater to which the present invention is applied;

<First embodiment>
A first embodiment of a fluid heater to which the present invention is applied and a method of manufacturing the fluid heater will be described below.
The fluid heater of the first embodiment heats various types of fluids to be heated, such as various gases, vapors, liquids, and gas-liquid mixed fluids, using sheathed heaters installed in flow paths.

FIG. 1 is a cross-sectional view of the fluid heater of the first embodiment, showing a state cut along a plane including the central axis of the channel member. (The same applies to FIGS. 3 to 8, which will be described later.)
The fluid heater 1 includes a sheathed heater 10, a channel member 100, and the like.
The sheathed heater 10 has a heating wire made of, for example, a nichrome-based metal arranged along the inner diameter side of a sheath, which is a cylindrical member made of metal such as stainless alloy, along the longitudinal direction of the sheath. Insulator powder such as magnesia is enclosed in the interior of the housing.
The sheathed heater 10 has a heating portion 11, an end portion 12, and the like.

The heat generating portion 11 is a portion formed by winding, for example, a spiral shape at an intermediate portion in the longitudinal direction of the sheath.
The heat generating portion 11 is a portion that is arranged on the inner diameter side of the flow path member 100 and directly contacts the heated fluid flowing through the inside of the flow path member 100 to heat the heated fluid.
The end portion 12 is a linearly formed end portion of the sheath in the longitudinal direction, is arranged to protrude from the flow channel member 100 to the outer diameter side, and is connected to a power supply device (not shown) via a terminal 13 . part.
The end portion 12 is inserted into a projecting tubular portion 140 which will be described later.

The channel member 100 is a cylindrical member through which the fluid to be heated flows.
The channel member 100 is made of a heat-resistant metal material such as stainless steel.
The flow path member 100 is configured by joining a first member 110 and a second member 120, which are divided in the direction of the central axis (cylinder axis), by butt-welding the opposing edges.

The first member 110 and the second member 120 are, for example, cylindrical members formed by cutting a single cylindrical member, and are arranged concentrically.
The edge portion 111 of the first member 110 on the side of the second member 120 and the edge portion 121 of the second member 120 on the side of the first member 110 are on the side where the protruding tubular portion 140 described later is provided, and the first member 110 projects toward the second member 120 , and the second member 120 projects toward the first member 110 on the opposite side.

The protective member 130 is provided on the inner diameter side of the flow path member 100 at the junction between the edge portion 111 of the first member 110 and the edge portion 121 of the second member 120 .
The protective member 130 is formed in a belt shape from a metal such as stainless steel having a relatively thin plate thickness with respect to the main body portion of the flow path member 100, and extends along the welded portion to form the first member 110 and the second member 120. It is affixed in a fixed state to at least one of
The protective member 130 prevents the weld bead from projecting to the inner diameter side of the flow path member 100 and damaging the sheathed heater 10 when the first member 110 and the second member 120 are joined by welding. .

FIG. 2 is an enlarged cross-sectional view of a joint portion between a first member and a second member of a channel member in the fluid heater of the first embodiment.
2 shows the II part in FIG. 1, FIG. 2(a) shows the state after welding, and FIG. 2(b) shows the state before welding.
As shown in FIG. 2A, the edge portion 111 of the first member 110 and the edge portion 121 of the second member 120 are joined by a weld joint W made of weld metal.
By providing the protective member 130 along the welded joint W, the bead made of the weld metal is prevented from protruding toward the inner diameter side of the flow path member 100 .

As shown in FIG. 2(b), in the state before welding, a V-shaped groove opening toward the outer diameter side of the channel member 100 is formed between the edge portions 111 and 121. there is
Such a groove shape can be formed, for example, by cutting the edges 111 and 121 before welding.

The protruding tubular portion 140 is a cylindrical portion formed to protrude from the opening formed in the outer peripheral surface of the first member 110 of the flow path member 100 toward the outer diameter side of the first member 110 .
The end portion 12 of the sheathed heater 10 is inserted into the projecting tubular portion 140 .

In the first embodiment, as shown in FIG. 1, the dividing line PL between the edge portion 111 of the first member 110 and the edge portion 121 of the second member 120 is divided in the circumferential direction of the flow path member 100 by The region (the upper side in FIG. 1) where the projecting tubular portion 140 of the first member 110 is provided is arranged along a plane inclined with respect to the central axis of the flow path member 100 so as to protrude toward the second member 120 side. ing.
As a result, in the circumferential direction of the flow path member 100, the edge portion 111 of the first member 110 is located on the opposite side of the region where the projecting tubular portion 140 is provided (lower side in FIG. 1). A concave recess is formed on the side opposite to the side.

In the region of the recess, the parting line PL is located on the first member 110 side (opposite to the second member 120 side) with respect to the position of the projecting tubular portion 140 in the central axis direction of the flow path member 100. placed with an offset.
As a result, in the state before the second member 120 is joined to the first member 110, the sheathed heater 10 inserts the end portion 12 into the protruding tubular portion 140 along the longitudinal direction of the protruding tubular portion 140 from the concave portion side. It is possible to insert it into the inner diameter side of 110 of the first member.

Next, a method for manufacturing the fluid heater of the first embodiment will be described.
3A and 3B are diagrams showing a process of dividing the flow channel member in the manufacturing process of the fluid heater of the first embodiment.
First, as shown in FIG. 3( a ), a cylindrical member is prepared as a base material of the flow path member 100 .
Next, the channel member 100 is cut along the dividing line PL to be divided into the first member 110 and the second member 120 .
After that, the edges 111 and 121 are cut to form the groove shape shown in FIG. 2(b).

FIG. 4 is a diagram showing a manufacturing process of the fluid heater according to the first embodiment, which is a process of attaching the sheathed heater.
First, an opening is formed in a region adjacent to the edge portion 111 of the first member 110 and at a portion where the edge portion 111 protrudes toward the second member 120 in the circumferential direction of the flow path member 100 . The projecting tubular portion 140 is attached so as to communicate with the inside of the first member 110 via the .
The projecting tubular portion 140 is fixed to the first member 110 by, for example, welding. (First step)
After that, the sheathed heater 10 inserts the end portion 12 into the protruding tubular portion 140 along the longitudinal direction of the protruding tubular portion 140 from the above-described concave portion side of the edge portion 111 of the first member 110, It is installed so that the heat generating part 11 is arranged on the inner diameter side of 110 . (Second step)

FIG. 5 is a diagram showing a manufacturing process of the fluid heater according to the first embodiment, which is a process of attaching the second member to the first member.
A protective member 130 is attached to the edge portion 121 of the second member 120 .
After that, the second member 120 is placed concentrically with the first member 110 and brought close to the first member 110 .
At this time, the heat generating portion 11 of the sheathed heater 10 is inserted into the inner diameter side of the second member 120 .
Then, while the relative positions of the first member 110 and the second member 120 are restrained by a jig (not shown) so that the completed dimension in the longitudinal direction of the flow path member 100 has a predetermined length, the edge portions 111, Welding 121 is performed over the entire circumference of the channel member 100 . (Third step)

The effect of the first embodiment described above will be described below in comparison with Comparative Examples 1 and 2 of the present invention described below.
In comparative examples 1 and 2 and the embodiment described later, the same reference numerals are given to the parts common to the first embodiment, and the description is omitted, and mainly the differences will be described.
FIG. 6 is a cross-sectional view of a fluid heater that is Comparative Example 1 of the present invention.
In the fluid heater 1A of Comparative Example 1, instead of dividing the flow path member 100 into two, a heater insertion port 210 described below is provided. is inserted.

The heater insertion port 210 is a box-shaped portion that protrudes radially outward from the flow path member 100 from an opening obtained by cutting out a half of the flow path member 100 on the projecting cylindrical portion 140 side in the circumferential direction.
The heater insertion port 210 is provided with an opening 211 through which the sheathed heater 10 can be inserted into the passage member 100 and a lid portion 212 detachably attached to the opening 211 .
The projecting tubular portion 140 is provided so as to project from the lid portion 212 .
In Comparative Example 1, the sheathed heater 10 is inserted into the passage member 100 through the opening 211 with the lid portion 212 of the heater insertion port 210 removed.
After that, the lid portion 212 is attached and fixed such that the end portion 12 is inserted into the projecting tubular portion 140 .

In Comparative Example 1, the channel cross section inside the fluid heater 1A changes abruptly in the region where the heater insertion port 210 is provided, and the channel cross sectional area locally increases.
Therefore, part of the flow F of the fluid to be heated flowing from left to right in FIG.
Further, when the internal pressure of the fluid heater 1B is high, the heater insertion port 210 becomes a fragile portion where the pressure resistance is locally lowered, causing damage such as leakage of the fluid to be heated and breakage of the welded portion. is concerned.

FIG. 7 is a cross-sectional view of a fluid heater that is Comparative Example 2 of the present invention.
In the fluid heater 1B of Comparative Example 2, half of the region in which the sheathed heater 10 is provided in the cylinder axis direction of the flow path member 100 is cut away as the sheathed heater insertion part 150 on the side opposite to the projecting cylinder part 140 side. In addition, after inserting the sheathed heater 10 through the opening formed by this excision, the sheathed heater insertion portion 150 is returned to its original position and joined by welding.

In Comparative Example 2, it is difficult to precisely join the sheathed heater insertion portion 150 cut from the flow path member 100 to the flow path member 100 again.
For example, the lengthwise dimension of the sheathed heater inserting portion 150 is smaller than the dimension of the opening to which it is to be attached due to the cutting process, but it is difficult to join this by welding without gaps.
In addition, deformation in which the radius of curvature when the sheathed heater insertion portion 150 is viewed from the longitudinal direction changes from the original radius of curvature of the flow path member 100 (for example, the radius of curvature increases and opens) is also a problem. Become.
Furthermore, a joint along the axial direction of the flow channel member 100 is formed between the sheathed heater insertion portion 150 and the main body of the flow channel member 100 . When pressure is applied, it receives tensile stress, and especially when the pressure of the fluid to be heated is high, it becomes difficult to ensure reliability and durability.

In contrast, according to the first embodiment, the following effects can be obtained.
(1) The flow path member 100 is divided into the first member 110 and the second member 120 in the axial direction, and the sheathed heater 10 can be inserted along the longitudinal direction of the projecting cylindrical portion 140 along the shape of the dividing line PL. , the sheathed heater 10 is inserted into the inner diameter side of the first member 110 before joining the first member 110 and the second member 120, and then the first member 110 and the second member 120 are joined. becomes possible.
This makes it possible to easily obtain the fluid heater 1 incorporating the sheathed heater 10 while preventing the cross section of the flow path in the flow path member 100 from changing.
For this reason, the flow F of the fluid to be heated is suppressed from flowing avoiding the sheathed heater 10, and the heating efficiency is improved. It is possible to prevent problems caused by the provision of structural bodies having different shapes.
(2) Since the dividing line PL between the first member 110 and the second member 120 becomes a straight line inclined with respect to the central axis of the flow channel member 100 when viewed in the radial direction of the flow channel member 100, the first member Processing (cutting, formation of a bevel shape, etc.) for forming abutting portion between 110 and second member 120 is easy.
In addition, since no corner portion or the like is formed on the parting line PL, the welding work can be easily performed, and stress concentration can be prevented to ensure durability and reliability.
Furthermore, since the parting line PL does not intersect perpendicularly with the circumferential direction of the flow path member 100, even if the pressure of the fluid to be heated is high and a significant tensile stress is applied in the circumferential direction of the flow path member 100, It is possible to suppress damage to the parting line PL and ensure pressure resistance, durability, and reliability.
(3) By providing the protective member 130 on the inner diameter side of the welded portion between the first member 110 and the second member 120, the welding bead protrudes on the inner diameter side of the flow path member 100, damaging the sheathed heater 10. can be prevented.

<Second embodiment>
Next, a second embodiment of a fluid heater to which the present invention is applied will be described.
FIG. 8 is a cross-sectional view of the fluid heater of the second embodiment.
In the second embodiment, the dividing line PL between the first member 110 and the second member 120 is bent as shown in FIG.
The parting line PL is orthogonal to the central axis of the flow channel member 100 in the circumferential direction of the flow channel member 100 in the region near the protruding tubular portion 140 and in the region that is symmetrical to the center axis of the flow channel member 100 with this region. , and the other intermediate portions are arranged along a plane inclined with respect to the central axis of the flow path member 100 as in the first embodiment.
Also in the second embodiment described above, it is possible to obtain the same effect as the effect of the first embodiment described above.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) The specific configuration of the fluid heater and the manufacturing method thereof is not limited to the above-described embodiments, and can be changed as appropriate.
For example, the structure, shape, material, manufacturing method, quantity, arrangement, etc. of each member can be appropriately changed from the configuration of each embodiment.
(2) In each embodiment, the cross-sectional shape of the flow path member is, for example, a circle (perfect circle), but the present invention is not limited to this, and has a cross-sectional shape of, for example, an elliptical, rectangular, or other shape. It can also be applied to a fluid heater having a channel member.
Further, the shape of the sheathed heater that is curved or bent inside the flow path member is not particularly limited to the spiral shape as in the embodiment, and can be changed as appropriate.
(3) In each embodiment, the first member and the second member of the flow path member are joined by butt welding, but the joining method is not limited to this and can be changed as appropriate.
For example, by placing a doubler (laminate) across the first member and the second member, for example, by a mechanical fastening means such as structural adhesives, friction stir welding, rivets, etc., other than welding, or , these techniques may be used in combination with welding.
Also, the first member and the second member may be detachably connected, for example, by flange connection.

Reference Signs List 1, 1A, 1B, 1C Fluid heater 10 Sheathed heater 11 Exothermic part 12 End 13 Terminal 100 Channel member 110 First member 111 Edge 120 Second member 121 Edge 130 Protection member 140 Protruding cylinder 150 Seed Heater insertion part 210 Heater insertion port 211 Opening 212 Lid part PL Parting line W Welded joint F Flow of fluid to be heated

Claims (5)

a cylindrical channel member through which the fluid to be heated flows;
A heat generating wire and insulating powder are housed inside a sheath formed in a cylindrical shape, and an intermediate portion arranged on the inner diameter side of the flow channel member and an end arranged protruding to the outside of the flow channel member. A fluid heater comprising: a sheathed heater having a portion;
The flow path member is configured by connecting a first member and a second member which are divided in the cylinder axis direction,
a protruding tubular portion formed protruding outward from the first member and into which the end portion of the sheathed heater is inserted;
The first member has a part at the end joined to the second member that is closer to the second member than the other part so that the sheathed heater can be inserted along the longitudinal direction of the protruding cylindrical part. has a concave recess on the opposite side,
the flow path member maintains a basic cross-sectional shape from a region upstream of the sheathed heater to a region downstream of the sheathed heater;
The inner peripheral surface of the projecting cylindrical portion and the outer peripheral surface of the end portion of the sheathed heater are in contact with each other.
A fluid heater characterized by: 2. The fluid according to claim 1, wherein a joint portion where the first member and the second member are joined is arranged along a plane inclined with respect to a cylinder axis direction of the channel member. Heater. The first member and the second member are joined by butt welding,
2. A protection member is provided along the inner peripheral surface of the flow path member at the junction between the first member and the second member to prevent the weld bead from protruding toward the inner diameter side. Or the fluid heater according to claim 2. a cylindrical channel member through which the fluid to be heated flows;
A heat generating wire and insulating powder are housed inside a sheath formed in a cylindrical shape, and an intermediate portion arranged on the inner diameter side of the flow channel member and an end arranged projecting to the outside of the flow channel member. A method for manufacturing a fluid heater comprising: a sheathed heater having a portion;
The flow path member is configured to have a first member and a second member that are divided in the cylinder axis direction,
a first step of attaching to the first member a protruding cylindrical portion which is formed to protrude outward and into which the end portion of the sheathed heater is inserted;
The end portion of the sheathed heater is inserted along the longitudinal direction of the projecting cylindrical portion, and the heat generating portion is disposed inside the first member when viewed from the cylindrical axis direction of the flow path member. a step of 2;
a third step of joining the first member and the second member in a butted state ;
the flow path member maintains a basic cross-sectional shape from a region upstream of the sheathed heater to a region downstream of the sheathed heater;
The inner peripheral surface of the projecting cylindrical portion and the outer peripheral surface of the end portion of the sheathed heater are in contact with each other.
A method of manufacturing a fluid heater, characterized by: The third step includes butt welding the first member and the second member,
5. The fluid heater according to claim 4, wherein the welding is performed in a state in which a protective member is provided to prevent the weld bead from protruding on the inner diameter side of the joint between the first member and the second member. Production method.

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