JP6887659B2 - Hot air generator - Google Patents

Description

The present invention relates to a hot air generator. More specifically, the present invention relates to a hot air generator having a tubular body having a passage through which a fluid flows, and a planar heating element arranged along the flow direction of the passage.

Conventionally, as the hot air generator as described above, for example, the one described in Patent Document 1 is known. In this device, the planar heating elements are merely arranged meandering along the length direction of the frame, and the efficiency of heat exchange in the planar heating elements is insufficient. Further, this planar heating element is merely inserted into a groove that is slidable with respect to the frame, and there is a possibility that the planar heating element may fall out of the groove due to thermal deformation of the heating element itself due to a temperature change of the planar heating element.

Utility Model Registration No. 3089428

In view of such conventional circumstances, it is an object of the present invention to provide a hot air generator having a compact structure and excellent heat exchange efficiency and hot air generation efficiency.

In order to achieve the above object, the feature of the hot air generator according to the present invention is that a tubular body having a passage for flowing a fluid inside and a planar portion of a planar heating element are arranged along the flow direction of the passage. In a configuration having a planar heating element, the planar heating element has a meandering current path formed by slits, and has a plurality of stages and slits in a direction intersecting the flow direction. Is arranged so that the longitudinal direction of the is parallel to the direction orthogonal to the flow, a rectifying plate oriented toward the planar heating element is provided in the space, and a part of the fluid is passed through the slit by the rectifying plate. It is to move to another adjacent space.

According to the above configuration, since the planar heating elements are arranged in a plurality of stages with a space in the direction intersecting the flow direction of the passage, the pressure loss is small and a relatively large flow rate of the fluid is passed through the passage even if the pressure is not high. Can be distributed to. Then, since the fluid moves downstream in the space along the planar portion of the planar heating element, the contact time with the planar heating element is long and the heat exchange efficiency is high. Moreover, since a straightening vane oriented toward the planar heating element is provided in the space, a part of the fluid moving in the space is sprayed on the planar heating element by the straightening vane. Therefore, the fluid flowing through the passage frequently exchanges heat with the planar heating element, and can efficiently generate hot air. Further, the planar heating element has a meandering current path formed by the slits, and is arranged so that the longitudinal direction of the slits is parallel to the direction orthogonal to the flow direction. Therefore, a part of the fluid flowing in the space flows by the straightening vane so as to pass through the slit and diffuse to another adjacent space, causing turbulence. As a result, the contact opportunity and time with the planar heating element can be increased, and the efficiency of heat exchange is further improved.

Further, the planar heating element further has a bent portion formed by bending a widthwise end portion intersecting the longitudinal direction of the slit, and the bent portion is locked to an insulating member to cause the planar heating element. It is good to keep. Since the curved portion formed by bending the end portion in the width direction is locked to the insulating member to hold the planar heating element, it is possible to prevent the planar heating element from falling off from the insulating member even when the temperature rises.

The planar heating element may be curved so as to be convex downward in the vertical direction. As a result, even if the planar heating element softens due to heat generation, the weight of the heating element acts in the vertical direction Z, and its deformation can be induced in the vertical direction, resulting in a shape like a catenary curve. Since this shape is mechanically stable, the shape of the heating element is maintained even when it is softened, and it is prevented from falling off.

In such a case, the straightening vane has a curved recess that curves toward the center of the main body between the side ends of the main body of the straightening vane located in the horizontal direction orthogonal to the flow direction, and the bending. The recess may be positioned below the planar heating element. Even if the planar heating element softens (deforms) in the vertical direction Z due to heat generation, this curved recess can prevent a ground fault (contact) between the planar heating element and the rectifying plate and guide the fluid to the adjacent space. The efficiency of heat exchange is also good.

The insulating member may have an opening that opens upward and a storage space that communicates with the opening and accommodates the widthwise end. As a result, it is possible to prevent the planar heating element from falling off and to suppress the movement (deformation) of the planar heating element in the horizontal direction orthogonal to the flow direction.

In such a case, the insulating member includes a first protrusion that projects diagonally upward from the first main body, a first insulator having a first recess below the first protrusion, and a second protrusion that protrudes upward from the second main body. It is composed of a second insulator having a second recess in its lower portion, the opening is composed of the first protrusion and the second protrusion, and the accommodation space is composed of the first recess and the second recess. It should be done.

The insulating member may further include a protrusion penetrating the slit. Further, a cushioning member that penetrates the slit and is hooked on the insulating member may be further provided. Further, a rod-shaped body penetrating each slit of the planar heating element arranged in a plurality of directions intersecting the flow direction may be further provided. According to these configurations, it is possible to prevent short circuits between current paths (linear portions) and suppress deformation in the flow direction.

The tubular body may have a support portion that supports the insulating member along the flow direction. As a result, since the insulating member that holds the end of the heating element is not arranged in the passage, the flow of the fluid is not obstructed and heat exchange is efficiently performed.

According to the above-mentioned features of the hot air generator according to the present invention, it is possible to improve the efficiency of heat exchange and the efficiency of hot air generation in spite of its compact structure.

Other objects, configurations and effects of the present invention will become apparent from the sections of embodiments of the invention below.

It is a perspective view of the hot air generator which concerns on this invention. It is an exploded perspective view of a hot air generator. It is an exploded perspective view of a housing. It is a flow direction view of a hot air generator. It is an enlarged view of the part A of FIG. It is the B part enlarged view of FIG. It is the C part enlarged view of FIG. It is an enlarged view of D part of FIG. It is a perspective view of a planar heating element and an insulator. It is a figure which shows typically the flow of the fluid in a passage. It is a figure which shows typically the flow of the fluid in a slit. It is a figure which shows the modification example of an insulator.

Next, the present invention will be described in more detail with reference to the accompanying drawings as appropriate.
As shown in FIGS. 1 to 4, the hot air generator 1 according to the present invention generally includes a tubular body 2 having a passage 3 for flowing air as a fluid G inside, and a flow direction of the fluid G in the passage 3. It has a planar heating element 4 arranged along F. A plurality of planar heating elements 4 are arranged with a space S in the vertical direction Z (the height direction of the housing 10 described later) orthogonal to the flow direction F. The space S is formed in a hierarchical manner with the planar heating element 4 sandwiched in the vertical direction Z orthogonal to the flow direction F, and a plurality of straightening plates 5 oriented toward the planar heating element 4 are arranged in the space S. .. The hot air generator 1 is housed in the duct or connected to the duct, for example, and heats the fluid G flowing through the duct. In the present embodiment, a total of 12 planar heating elements 4 are installed in four rows in the horizontal direction H orthogonal to the flow direction F and three stages in the vertical direction Z.

As shown in FIGS. 1 to 3, the tubular body 2 is composed of, for example, a metal housing 10, and is housed in, for example, a metal case 6. The case 6 includes a pair of substantially U-shaped frames 61 and 61 to which the housing 10 is attached, and a storage portion 64 fixed to one end of the frame 61 and accommodating the blanket 62 and the heat-resistant cable 63. The heat-resistant cable 63 electrically connects the feeding rods 7a to 7f, which are electrically connected to the planar heating element 4, and the outside. One of the storage portions 64 is provided with a mounting plate 66 to which a terminal 65 connected to the heat-resistant cable 63 is attached.

As shown in FIG. 7, the power feeding rod 7 penetrates the accommodating portion 64 via the first insulating member 81 having the convex portion 81a and the second insulating member 82 having the concave portion 82a that fits with the convex portion 81a. As a result, the insulation between the case 6 and the feeding rod 7 is ensured and the airtightness is ensured. Further, as shown in FIG. 8, one end of the power feeding rod 7 is fixed to the terminal 63a of the heat-resistant cable 63 via the nuts 71 and 71 and the washers 72 and 73. A protective tube 8 that covers the outer circumference of the power feeding rod 7 is provided to ensure insulation from the housing 10. A cover 67 is provided on the mounting plate 66.

As shown in FIG. 3, the housing 10 is formed on a pair of side walls 11 and 11 along the flow direction F, a partition plate 12 erected in parallel with the side wall 11 at an appropriate distance between them, and a frame 61. It has a fixing portion 13 fixed by bolts and nuts or the like. The pair of side walls 11 and 11 and the partition plate 12 are provided with a substantially L-shaped support portion 14 for supporting the insulating member 20 that holds the planar heating element 4 described later. Further, the partition plate 12 is formed with a projecting piece 12a having a through hole 12b through which the feeding rod 7 is inserted.

As shown in FIGS. 1 and 9, the planar heating element 4 is formed in a plate shape and a rectangular shape, and a plurality of slits 41 are alternately formed in the horizontal direction H from the widthwise end portions 42 and 42 along the flow direction F. A meandering current path 40 is formed by cutting along the line. That is, the longitudinal direction of the slit 41 is orthogonal to the flow direction F of the fluid G. The linear portion 40x between the pair of widthwise end portions 42, 42 is curved downward in the vertical direction Z so as to form a gentle arc shape (arch shape) in the flow direction F of the fluid G. There is. When the planar heating element 4 softens due to heat generation, it becomes a catenary curve-like shape due to its own weight. This shape is mechanically stable, and even if it softens, the planar heating element 4 is prevented from falling off. Further, as shown in FIGS. 5, 6 and 9, the widthwise end portion 42 is bent substantially orthogonal to the linear portion 40x of the current path 40, and the tip portion 43 of the widthwise end portion 42 is substantially orthogonal to the linear portion 40x. It is formed by bending it at a right angle. The planar heating element 4 is made of a conductive material such as Fe-Cr-Al or a nickel-chromium alloy, and may be appropriately changed depending on the operating temperature and the like.

The current path ends 40a and 40b of the current path 40 are located on the upstream side U and the downstream side D in the flow direction F, and the respective end portions 40a and 40b are electrically connected to the feeding rod 7 via the connecting member 44. Will be done. In the present embodiment, as shown in FIGS. 1 and 2, one circuit is composed of the planar heating elements 4 in the first and second rows on the storage unit 64 side. On the upstream side U, the lower and middle planar heating elements 4 in the first row on the storage unit 64 side are connected to the power supply rod 7b in the middle stage via the connecting member 44a, and the lower and middle stages in the second row on the storage unit 64 side. The planar heating element 4 of the above is connected to the lower feeding rod 7a via a connecting member 44b. Further, the upper planar heating elements 4 in the first and second rows on the storage portion 64 side are connected to the upper feeding rod 7c via the connecting members 44c and 44c, respectively. On the downstream side D, on the downstream side D, the middle and upper planar heating elements 4 in the first and second rows on the storage portion 64 side are connected via the connecting member 44d, respectively, and the lower adjacent surfaces of the planar heating element 4 are connected. The heating elements 4 and 4 are connected via a connecting member 44e. The planar heating elements 4 in the third and fourth rows on the storage portion 64 side are symmetrical with the connecting members 44a to 44e connected to the planar heating elements 4 in the first and second rows on the upstream side and the downstream side. It is arranged and connected to form an equivalent circuit.

As shown in FIGS. 4 to 6 and 9, the insulator 20 as an insulating member is composed of first and second insulators 21 and 22 extending along the flow direction F and forming a pair, and is fitted and fixed to the support portion 14. It is fixed by the tool 29. The insulator 20 is made of, for example, a so-called ceramic material or a silicon nitride material mainly composed of alumina, alumina silice, mullite, zircon or cordylite, and may be appropriately changed depending on the operating temperature and the like. The insulator 20 electrically insulates the planar heating element 4 from the housing 10 and the case 6.

The first insulator 21 includes a first protruding portion 21b that projects diagonally upward from the first main body portion 21a, and a first recess 21c below the first protruding portion 21b. On the other hand, the second insulator 22 includes a second protruding portion 22b protruding upward from the second main body portion 22a and a second recess 22c below the second protruding portion 22b. Further, the insulators 21 and 22 are provided with first and second through holes 21d and 22d through which the fixture 29 penetrates. By arranging the first and second recesses 21c and 22c so as to face each other, a storage space 23 for accommodating the widthwise end portion 42 is formed, and the movement of the planar heating element 4 in the horizontal direction H is restricted. Moreover, an opening 24 is formed above the accommodation space 23 by the first protruding portion 21b and the second protruding portion 22b, and the tip of the first insulator 21 is positioned on the central side of the planar heating element 4. Since the portion 43 is located below the first protruding portion 21b, the end portion 42 in the width direction is also prevented from coming off. The first and second insulators 21 and 22 need only have the strength to be fixed to the substantially L-shaped support portion 14 by the fixture 29 via the through holes 21d and 22d, and the first and second main body portions. By forming the 21a and 22a thinly, the heat capacity of the insulating member can be reduced.

Here, as shown in FIGS. 3, 5 and 6, the straightening vane 5 in the present embodiment is composed of three types of straightening vanes 50A to 50C having different shapes. The first straightening vane 50A has a rectangular shape and is attached to the upper part of the side wall 11 and the partition plate 12 so as to be inclined toward the upstream side U. The second straightening vane 50B has a pair of projecting portions 52, 52 protruding outward in the horizontal direction H from the side end portions 51a located in the horizontal direction H on one side of the plate-shaped main body portion 51, and the other side. A curved recess 53 that curves toward the center of the main body 51 is formed between the side end portions 51a. The protruding portion 52 is fixed below the supporting portion 14 and is oriented so as to intersect the flow direction F and toward the planar heating element 4. The third straightening vane 50C is provided with a fixing portion 54 fixed to the frame 61 on the above-mentioned protruding portion 52.

As shown in FIGS. 3 to 6, the curved recesses 53 of the second and third straightening vanes 50B and 50C have their ends 53a on the side surface of the support portion 14 in the longitudinal direction L (flow direction F) of the passage 3. It is positioned so as to be close to the planar heating element 4 and separated from the planar heating element 4 from the end portion 53a toward the central portion 53b. Here, the planar heating element 4 is located above the vertical direction Z of the second and third straightening vanes 50B and 50C. As described above, since the planar heating element 4 is formed in an arc shape that is convex downward, when the planar heating element 4 softens and thermally expands due to its own heat generation, its thermal deformation is vertical due to its own weight. Guided in direction Z. Further, the amount of thermal deformation increases toward the center between the widthwise end portions 42, 42. Therefore, as shown by the alternate long and short dash line in FIG. 6, the second straightening vane 50B'without the curved portion 53 is close to the planar heating element 4, so that the fluid G can be easily guided to the planar heating element 4, but heat. There is a risk that the planar heating element 4 and the straightening vane will come into contact with each other due to deformation. Therefore, by forming the curved recess 53 in the straightening vane, a ground fault between the planar heating element 4 and the second and third straightening vanes 50B and 50C is prevented, and another planar heating element 4 adjacent to the fluid G is prevented. It is possible to secure the movement (spraying) to the heat exchange and improve the efficiency of heat exchange.

As shown in FIG. 10, the space S is circulated by arranging a plurality of such rectifying plates 50A to 50C at appropriate intervals along the flow direction F and inclining them so as to intersect the flow direction F. The fluid G flows toward the planar heating element 4 by the rectifying plates 50A to 50C and collides with the planar heating element 4, so that heat exchange is frequently performed with the planar heating element 4, and the efficiency of heat exchange is improved. To do. Moreover, since the slit 41 is formed in the planar heating element 4, a part of the fluid G directed to the planar heating element 4 by the straightening vanes 50A to 50C passes through the slit 41 and is adjacent to another. Move to space. At that time, as shown in FIG. 11, the fluid G that has passed through the slit 41 causes a turbulent flow, which further improves the efficiency of heat exchange.

Finally, the possibility of still another embodiment of the present invention will be described. In the following embodiments, the same members as those in the above-described embodiments are designated by the same reference numerals.
In the above embodiment, a total of 12 planar heating elements 4 are installed in 4 rows in the horizontal direction H and 3 stages in the vertical direction Z, but the number of planar heating elements 4 (number of rows, number of stages) can be appropriately set. Good. It is also possible to arrange a plurality of them in the flow direction F. It may be appropriately electrically connected according to the arrangement of the planar heating elements 4, and is not limited to the above embodiment.

Further, in the above embodiment, as shown in FIGS. 3 and 10, for example, the orientation of at least a part of the second and third straightening vanes 50B and 50C is set to the orientation of the other second and third straightening vanes 50B. By making it different from 50C, the fluid G flowing through the passage 3 comes into contact with the planar heating element 4 substantially evenly. However, the number, position, size, and orientation of the straightening vanes are such that the flow rate (flow velocity) of the fluid G and the planar heating element are such that the fluid G flowing through the passage 3 contacts the planar heating element 4 substantially evenly. It may be appropriately set according to the number of stages, the length, and the like of the body 4, and is not limited to the above embodiment.

In the above embodiment, the insulating member for hooking and holding the widthwise end portion 42 of the planar heating element 4 is made of an insulator 20, but the material is not limited to the above as long as the material can secure insulation. Further, in the above embodiment, the insulator 20 is composed of paired first and second insulators 21 and 22, but the embodiment is not limited to the above embodiment as long as it can prevent the planar heating element 4 from falling off. Absent.

Further, for example, as shown in FIG. 12A, a position facing the slit 41 of the planar heating element 4 for locking the protrusion 25 protruding upward to the top 21d of the protrusion 21b of the first insulator 21. It may be erected in. In such a case, the planar heating element 4 is locked to the insulator 20 with the protrusion 25 fitted in the slit 41, and the insulator 20 is fixed to the support portion 14 of the housing 10 by the fixture 29. The protrusion 25 prevents a short circuit between the linear portions 40x and 40x adjacent to each other in the direction along the longitudinal direction L (flow direction F) of the passage 3. Further, the position of the protrusion 25 is not limited to this, and the protrusion 25 can be provided in the accommodation space 23 as shown in FIG. Further, the protrusion 25 may be integrated with the insulator 20 or may be a separate body. As shown in FIG. 3C, for example, a cushioning member 26 is inserted into the slit 41 near the end portion 42 in the width direction, or an alumina adhesive is placed on the insulator 20 to prevent a short circuit due to contact between the linear portions 40x. You can also do it. Further, for example, it is also possible to penetrate the slit 41 of each planar heating element 4 in which an insulating rod-shaped body is laminated in the vertical direction Z. It should be noted that these modified examples can also be implemented in combination.

Further, in the above embodiment, the planar heating element 4 is curved in a convex shape downward in the vertical direction, but the shape is not limited to this, and for example, it may be flat.

Further, in the above embodiment, the planar heating element 4 is arranged along the flow direction F by providing the support portion 14 that supports the insulating member 20 along the flow direction F. However, the present invention is not limited to this, and it is also possible to provide a support portion 14 that supports the insulating member 20 along the direction intersecting the flow direction F. However, in such a case, the support portion is arranged in the passage, and the flow of the fluid is hindered, so that the above embodiment is excellent.

In the above embodiment, air has been described as an example of the fluid G, but the present invention is not limited to this, and the fluid G is also applicable to gases such as hydrogen, oxygen, nitrogen, argon, and helium.

The hot air generator according to the present invention can also be used, for example, as a secondary firing device for a chimney, a catalyst for an automobile or the like, a carbon removing device, a gas introduction device for a semiconductor device, or a paint drying device for an automobile or the like.
Further, since the present invention is an electric heating method, it is clean. That is, in the case of the combustion method using gas or the like, soot, exhaust gas components, and the like are mixed in the fluid G, but this is not the case. Therefore, for example, it is used for preheating the gas introduced into the combustion furnace. Further, for example, it can be used when introducing high-temperature air (gas) in order to quickly restore (heat the temperature) the internal atmospheric temperature when opening and closing the door of the furnace. Further, in order to improve the heating efficiency of the work in a furnace used at a low temperature (about ~ 500 ° C.), not only radiation but also convection effect may be used. At that time, it is also possible to introduce the hot air into the furnace and circulate it to generate and introduce the hot air again by the hot air generator.

1: Hot air generator, 2: Cylindrical body, 3: Passage, 4: Planar heating element, 5: Insulator, 6: Case, 7a to 7f: Power supply rod, 8: Protective tube, 10: Housing, 11 : Side wall, 12: Partition plate, 12a: Projection piece, 12b: Through hole, 13: Fixed part, 14: Support part, 20: Insulator (insulating member), 21: First insulator, 21a: First main body part, 21b : First protrusion, 21c: First recess, 21d: First through hole, 22: Second insulator, 22a: Second main body, 22b: Second protrusion, 22c: Second recess, 22d: Second penetration Hole, 23: Containment space, 24: Opening, 25: Protrusion, 26: Buffer member, 29: Fixture, 40: Current path, 40a: Upstream current path end, 40b: Downstream current path end, 40x: Linear part, 41: Slit, 42: Width direction end part, 43: Tip part, 44a to 44e: Connecting member, 50A to 50C: First to third straightening vanes, 51: Main body part, 51a: Side end Part, 52: Protruding part, 53: Curved recess, 53a: End part, 53b: Central part, 61: Frame, 62: Blanket, 62a: Through hole, 63: Heat resistant cable, 64: Storage part, 65: Terminal, 66 : Mounting plate, 67: Cover, 71: Nut, 72: Spring insulator, 73: Flat insulator, 81: First insulating member, 81a: Convex part, 82: Second insulating member, 82a: Concave, D: Downstream side, F: Flow direction, G: Fluid (air), H: Horizontal direction, S: Space, U: Upstream side, Z: Vertical direction

Claims (10)

A hot air generator having a tubular body having a passage through which a fluid flows, and a planar heating element in which a planar portion of the planar heating element is arranged along the flow direction of the passage.
The planar heating element has a meandering current path formed by slits, and has a plurality of stages in a direction intersecting the flow direction and a direction in which the longitudinal direction of the slit is orthogonal to the flow direction. Arranged so as to be parallel to
A straightening vane oriented toward the planar heating element is provided in the space.
A hot air generator that allows a part of the fluid to pass through the slit and move to another adjacent space by the straightening vane. The planar heating element further has a bent portion formed by bending a widthwise end portion intersecting the longitudinal direction of the slit, and the bent portion is locked to an insulating member to hold the planar heating element. The hot air generator according to claim 1. The hot air generator according to claim 1 or 2, wherein the planar heating element is curved so as to be convex downward in the vertical direction. The straightening vane has a curved recess curved toward the center of the main body between side ends of the main body of the straightening vane located in a horizontal direction orthogonal to the flow direction, and the curved recess is formed. The hot air generator according to claim 3, which is located below the planar heating element. The hot air generator according to claim 2, wherein the insulating member has an opening that opens upward and a storage space that communicates with the opening and accommodates the widthwise end portion. The insulating member includes a first insulator projecting diagonally upward from the first main body portion, a first insulator having a first recess below the first protruding portion, and a second projecting portion projecting upward from the second main body portion and its lower portion. Consists of a second insulator with a second recess,
The opening is composed of the first protrusion and the second protrusion.
The hot air generator according to claim 5, wherein the accommodation space is composed of the first recess and the second recess. The hot air generator according to any one of claims 2, 5 and 6, wherein the insulating member further includes a protrusion penetrating the slit. The hot air generator according to any one of claims 2, 5 to 7, further comprising a cushioning member that penetrates the slit and is hooked on the insulating member. The hot air generating device according to any one of claims 2, 5 to 8, further comprising a rod-shaped body penetrating each slit of the planar heating element arranged in a plurality of directions intersecting the flow direction. The hot air generator according to any one of claims 2 to 9, wherein the tubular body has a support portion that supports the insulating member along the flow direction.

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