Heating device

Abstract

To provide a technology which can homogeneously transmit heat to fluid to be heated from an external peripheral face and an internal peripheral face of a heater.SOLUTION: A heating device comprises: a first flow passage which is formed between an internal peripheral face of a first housing and an external peripheral face of a heater; a second flow passage being a second flow passage which communicates with the first flow passage, and is formed between an internal peripheral face of the heater and an external peripheral face of an axial core member; and a third flow passage being a third flow passage communicating with the first flow passage and the second flow passage, and formed at a position located inside the second flow passage or at a position located outside the first flow passage. Fluid to he heated flowing through the first flow passage may be shunt to the second flow passage and the third flow passage, and the fluid to be heated flowing through the first flow passage and the second flow passage may be heated by the heater. When viewing a cross-section orthogonal to an axial direction of the heater, a width of the first flow passage in a short direction, a width of the second flow passage in the short direction, and a width of the third flow passage in the short direction may be the same. A cross-sectional area of the first flow passage may be equal to a sum of a cross-sectional area of the second flow passage and a cross-sectional area of the third flow passage.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a heating device that heats a fluid to be heated. [Background technology]

[0002] Patent Document 1 discloses an instantaneous heat exchanger including a cylindrical heater having a hollow portion, a housing that covers the outer periphery of the heater and forms an outer flow path between the housing and the outer peripheral surface of the heater, and a shaft member that is provided in the hollow portion of the heater and forms an inner flow path between the housing and the inner peripheral surface of the heater. The instantaneous heat exchanger of Patent Document 1 uses the heater to heat a fluid to be heated that flows through the outer flow path and the inner flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-118351 Summary of the Invention [Problem to be solved by the invention]

[0004] In a configuration including a cylindrical heater, the heater has different outer and inner diameters, so when heat is transferred from the outer and inner peripheral surfaces of the heater to the heated fluid, there may be a difference in the way heat is transferred from the outer peripheral surface of the heater and the way heat is transferred from the inner peripheral surface of the heater. Therefore, this specification provides a technology that allows heat to be transferred equally from the outer peripheral surface and the inner peripheral surface of the heater to the heated fluid. [Means for solving the problem]

[0005] In a first aspect of the present technology, a heating device includes a cylindrical first housing, a cylindrical heater disposed inside the first housing, a shaft member disposed inside the heater, a first flow path formed between an inner circumferential surface of the first housing and an outer circumferential surface of the heater, a second flow path communicating with the first flow path, the second flow path being formed between the inner circumferential surface of the heater and the outer circumferential surface of the shaft member, and a third flow path communicating with the first flow path and the second flow path, the third flow path being formed at a position inside the second flow path or outside the first flow path. A fluid to be heated flowing through the first flow path may be divided into the second flow path and the third flow path, and the fluid to be heated flowing through the first flow path and the second flow path may be heated by the heater. When viewed in a cross section perpendicular to the axial direction of the heater, a width in a lateral direction of the first flow path, a width in a lateral direction of the second flow path, and a width in a lateral direction of the third flow path may be equal. The cross-sectional area of ​​the first flow path may be equal to the sum of the cross-sectional area of ​​the second flow path and the cross-sectional area of ​​the third flow path.

[0006] With this configuration, the resistance to the flow of the heated fluid is equivalent in the first, second, and third flow paths. As a result, the flow velocity of the heated fluid in the first flow path, the flow velocity of the heated fluid in the second flow path, and the flow velocity of the heated fluid in the third flow path are equivalent. As a result, the flow velocity of the heated fluid flowing along the outer circumferential surface of the heater in the first flow path is equivalent to the flow velocity of the heated fluid flowing along the inner circumferential surface of the heater in the second flow path. With the above configuration, heat from the heater is transferred from the outer circumferential surface of the heater to the heated fluid flowing in the first flow path and from the inner circumferential surface of the heater to the heated fluid flowing in the second flow path. Since the flow velocity of the heated fluid flowing along the outer circumferential surface of the heater is equivalent to the flow velocity of the heated fluid flowing along the inner circumferential surface of the heater, the heat flux from the outer circumferential surface of the heater is equivalent to the heat flux from the inner circumferential surface of the heater. Therefore, heat can be transferred equally from the outer circumferential surface and the inner circumferential surface of the heater to the heated fluid.

[0007] In a second aspect, in the first aspect, the third flow path may be formed at a position more inward than the second flow path. With this configuration, the size of the heating device can be reduced.

[0008] In a third aspect, in the second aspect, the third flow path may be formed inside a second housing made of metal and embedded in the shaft member made of resin.

[0009] With this configuration, the shaft member is easy to mold, which makes it easier to position the third flow path more inward than the second flow path. Furthermore, the metal second housing can suppress deformation, such as warping, of the resin shaft member. This can suppress differences in width among the first flow path, the second flow path, and the third flow path.

[0010] In a fourth aspect, in the first aspect, the third flow path may be formed at a position outside the first flow path, which improves the degree of freedom in the position and shape of the third flow path. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a cross section parallel to the axial direction of a heating device according to a first embodiment. [Figure 2] 2 is a cross-sectional view (cross-sectional view taken along II-II in FIG. 1) of a section perpendicular to the axial direction of the heating device of the first embodiment. [Figure 3] FIG. 10 is a cross-sectional view of a cross section parallel to the axial direction of the heating device of the second embodiment. [Figure 4] 4 is a cross-sectional view (IV-IV cross-sectional view in FIG. 3) of a section perpendicular to the axial direction of the heating device of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] (First Example) A heating device 2 of a first embodiment will be described with reference to the drawings. FIGS. 1 and 2 are cross-sectional views of the heating device 2 of the first embodiment. As shown in FIGS. 1 and 2, the heating device 2 includes a first housing 10, a heater 30 disposed inside the first housing 10, a shaft member 40 disposed inside the heater 30, and a second housing 60 embedded in the shaft member 40. The heating device 2 also includes a first flow path 21, a second flow path 22, a third flow path 23, and a connecting flow path 24 through which a fluid to be heated flows. The fluid to be heated is, for example, a liquid such as water or a gas such as air. The heating device 2 is a device that heats the fluid to be heated using the heater 30.

[0013] The first housing 10 is made of metal or resin and is generally cylindrical. In a modified example, the first housing 10 may be generally elliptical or rectangular. The first housing 10 surrounds the heater 30.

[0014] A metal or resin cap 12 is fixed to the axial end of the first housing 10. The cap 12 covers the axial end of the heater 30 and the axial end of the shaft member 40. Connection flow paths 24 are formed between the inner surface of the cap 12 and the axial end of the heater 30, and between the inner surface of the cap 12 and the axial end of the shaft member 40.

[0015] The heater 30 is, for example, a ceramic heater equipped with a resistance heating element that generates heat when electricity is applied. The heater 30 is generally cylindrical. In a modified example, the heater 30 may be generally elliptical or rectangular. The heater 30 surrounds the shaft member 40.

[0016] The heater 30 is disposed so that its axial direction is parallel to the axial direction of the first housing 10. A plurality of first support members 50 are disposed between the heater 30 and the first housing 10. The plurality of first support members 50 are disposed in a line at intervals in the circumferential direction of the heater 30. The plurality of first support members 50 are disposed so as to support non-heat-generating portions of the heater 30.

[0017] An outer peripheral surface 32 of the heater 30 faces the inner peripheral surface 14 of the first housing 10. A plurality of first support members 50 support the heater 30 and the first housing 10 so that a gap is formed between the outer peripheral surface 32 of the heater 30 and the inner peripheral surface 14 of the first housing 10. A first flow path 21 is formed between the outer peripheral surface 32 of the heater 30 and the inner peripheral surface 14 of the first housing 10. The outer peripheral surface 32 of the heater 30 is in contact with the fluid to be heated flowing through the first flow path 21, and heat is transferred from the outer peripheral surface 32 of the heater 30 to the fluid to be heated. The heater 30 heats the fluid to be heated flowing through the first flow path 21.

[0018] The shaft core member 40 is made of resin or metal and is generally cylindrical. In a modified example, the shaft core member 40 may be generally elliptical cylindrical or rectangular prism-shaped. The shaft core member 40 is arranged so that its axial direction is parallel to the axial direction of the first housing 10 and the axial direction of the heater 30. A plurality of second support members 52 are arranged between the outer peripheral surface 42 of the shaft core member 40 and the inner peripheral surface 34 of the heater 30. The plurality of second support members 52 are arranged at intervals in the circumferential direction of the heater 30.

[0019] The outer peripheral surface 42 of the axial member 40 faces the inner peripheral surface 34 of the heater 30. A plurality of second support members 52 support the axial member 40 and the heater 30 so that a gap is formed between the outer peripheral surface 42 of the axial member 40 and the inner peripheral surface 34 of the heater 30. A second flow path 22 is formed between the outer peripheral surface 42 of the axial member 40 and the inner peripheral surface 34 of the heater 30. The inner peripheral surface 34 of the heater 30 is in contact with the fluid to be heated flowing through the second flow path 22, and heat is transferred from the inner peripheral surface 34 of the heater 30 to the fluid to be heated. The heater 30 heats the fluid to be heated flowing through the second flow path 22.

[0020] The second housing 60 is made of metal or resin and is generally configured in the shape of a flat, elongated cylinder. In a modified example, the second housing 60 may be generally configured in the shape of a flat, rectangular cylinder. The second housing 60 is embedded in the center of the shaft member 40. The second housing 60 is embedded in the shaft member 40 by, for example, insert molding. The second housing 60 is arranged so that its axial direction is parallel to the axial direction of the first housing 10, the axial direction of the heater 30, and the axial direction of the shaft member 40. A third flow path 23 is formed inside the second housing 60. The third flow path 23 is arranged at a position more inward than the second flow path 22.

[0021] The first flow path 21, the second flow path 22, and the third flow path 23 are connected to each other via a connecting flow path 24. The fluid to be heated flowing through the first flow path 21 is divided into the second flow path 22 and the third flow path 23 via the connecting flow path 24. The fluid to be heated flows through the first flow path 21 toward the connecting flow path 24, and flows through the second flow path 22 and the third flow path 23 in directions away from the connecting flow path 24.

[0022] In the heating device 2, when viewed in a cross section perpendicular to the axial direction of the heater 30 (see FIG. 2), the width W21 of the first flow path 21 in the short direction (i.e., the radial direction of the heater 30), the width W22 of the second flow path 22 in the short direction (i.e., the radial direction of the heater 30), and the width W23 of the third flow path 23 in the short direction are equal. The first housing 10, heater 30, and shaft member 40 of the heating device 2 are arranged so that W21 = W22. The second housing 60 is manufactured so that W21 = W22 = W23.

[0023] Furthermore, in the heating device 2, when viewed in a cross section perpendicular to the axial direction of the heater 30, the area S21 of the first flow path 21 is equal to the sum of the area S22 of the second flow path 22 and the area S23 of the third flow path 23.

[0024] In the heating device 2 described above, a fluid to be heated is supplied to the first flow path 21 from a supply source (not shown) of the fluid to be heated. The fluid to be heated supplied to the first flow path 21 flows axially through the first flow path 21 along the outer circumferential surface 32 of the heater 30 and is then branched into the second flow path 22 and the third flow path 23 via the connecting flow path 24. The fluid to be heated that flows into the second flow path 22 flows axially through the second flow path 22 along the inner circumferential surface 34 of the heater 30. The fluid to be heated that flows into the third flow path 23 flows axially through the third flow path 23 along the inner circumferential surface of the second housing 60. The heated fluid in the second flow path 22 and the heated fluid in the third flow path 23 flow in the opposite direction to the heated fluid in the first flow path 21. In the heating device 2, the heater 30 heats the heated fluid as it flows through the first flow path 21 and the second flow path 22. Heat is transferred from the outer peripheral surface 32 of the heater 30 to the fluid to be heated flowing through the first flow path 21 , and heat is transferred from the inner peripheral surface 34 of the heater 30 to the fluid to be heated flowing through the second flow path 22 .

[0025] (effect) The heating device 2 of the first embodiment has been described above. As is clear from the above description, the heating device 2 of the first embodiment includes a first flow path 21 formed between the inner circumferential surface 14 of the first housing 10 and the outer circumferential surface 32 of the heater 30, a second flow path 22 formed between the inner circumferential surface 34 of the heater 30 and the outer circumferential surface 42 of the shaft member 40, and a third flow path 23 formed at a position more inward than the second flow path 22. In the heating device 2, the fluid to be heated flowing through the first flow path 21 is divided into the second flow path 22 and the third flow path 23, and the fluid to be heated flowing through the first flow path 21 and the second flow path 22 is heated by the heater 30. In the heating device 2, when viewed in a cross section perpendicular to the axial direction of the heater 30, the width W21 in the lateral direction of the first flow path 21, the width W22 in the lateral direction of the second flow path 22, and the width W23 in the lateral direction of the third flow path 23 are equal to each other. Furthermore, the cross-sectional area S21 of the first flow path 21 is equal to the sum of the cross-sectional area S22 of the second flow path 22 and the cross-sectional area S23 of the third flow path 23.

[0026] With this configuration, the resistance to the flow of the heated fluid is equivalent in the first flow path 21, the second flow path 22, and the third flow path 23, and the Reynolds numbers in the flow paths 21, 22, and 23 can be made equivalent. As a result, the flow velocity of the heated fluid in the first flow path 21, the flow velocity of the heated fluid in the second flow path 22, and the flow velocity of the heated fluid in the third flow path 23 are equivalent. As a result, the flow velocity of the heated fluid flowing along the outer circumferential surface 32 of the heater 30 in the first flow path 21 is equivalent to the flow velocity of the heated fluid flowing along the inner circumferential surface 34 of the heater 30 in the second flow path 22. With the above configuration, heat from the heater 30 is transferred from the outer circumferential surface 32 of the heater 30 to the heated fluid flowing in the first flow path 21, and from the inner circumferential surface 34 of the heater 30 to the heated fluid flowing in the second flow path 22. At this time, the flow rate of the heated fluid flowing along the outer peripheral surface 32 of the heater 30 is equal to the flow rate of the heated fluid flowing along the inner peripheral surface 34 of the heater 30, so the heat flux from the outer peripheral surface 32 of the heater 30 is equal to the heat flux from the inner peripheral surface 34 of the heater 30. Therefore, heat can be transferred equally from the outer peripheral surface 32 and the inner peripheral surface 34 of the heater 30 to the heated fluid. The outer peripheral surface 32 and the inner peripheral surface 34 of the heater 30 can be effectively utilized.

[0027] Furthermore, since the third flow path 23 is located more inward than the second flow path 22, the size of the heating device 2 can be reduced. The third flow path 23 is formed inside the metal second housing 60 embedded in the resin shaft member 40. This configuration facilitates molding the shaft member 40, making it easier to position the third flow path 23 more inward than the second flow path 22. The metal second housing 60 also helps prevent deformation, such as warping, of the resin shaft member 40. This helps prevent differences from occurring among the width W21 of the first flow path 21, the width W22 of the second flow path 22, and the width W23 of the third flow path 23. Furthermore, it also helps prevent sink marks from occurring when molding the shaft member 40.

[0028] (Second Example) A heating device 2 of a second embodiment will be described with reference to the drawings. Detailed description of the second embodiment will be omitted for configurations similar to those of the first embodiment. FIGS. 3 and 4 are cross-sectional views of the heating device 2 of the second embodiment. As shown in FIGS. 3 and 4, in the heating device 2 of the second embodiment, the first housing 10 has a protrusion 16 that protrudes radially outward. A second housing 60 is embedded in the protrusion 16 of the first housing 10. The second housing 60 is disposed at a position outside the first flow path 21. A third flow path 23 is formed at a position outside the first flow path 21. This configuration allows for greater freedom in the position and shape of the third flow path 23.

[0029] (Variation) There is no particular limitation on the shapes of the second housing 60 and the third flow path 23. For example, the second housing 60 and the third flow path 23 may have a C-shape in a cross section perpendicular to the axial direction of the heater 30.

[0030] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0031] 2: heating device, 10: first housing, 12: cap, 14: inner peripheral surface, 16: convex portion, 21: first flow path, 22: second flow path, 23: third flow path, 24: connecting flow path, 30: heater, 32: outer peripheral surface, 34: inner peripheral surface, 40: shaft core member, 42: outer peripheral surface, 50: first support member, 52: second support member, 60: second housing

Claims

1. a cylindrical first housing; a cylindrical heater disposed inside the first housing; a shaft member disposed inside the heater; a first flow path formed between an inner circumferential surface of the first housing and an outer circumferential surface of the heater; a second flow path communicating with the first flow path, the second flow path being formed between an inner circumferential surface of the heater and an outer circumferential surface of the shaft member; a third flow path communicating with the first flow path and the second flow path, the third flow path being formed at a position more inward than the second flow path or more outward than the first flow path, a heating device in which a fluid to be heated flowing through the first flow path is divided into the second flow path and the third flow path, and the fluid to be heated flowing through the first flow path and the second flow path is heated by the heater, a heating device in which, when viewed in a cross section perpendicular to the axial direction of the heater, the width of the first flow path in the short side direction, the width of the second flow path in the short side direction, and the width of the third flow path in the short side direction are equal to each other, and the cross-sectional area of ​​the first flow path is equal to the sum of the cross-sectional areas of the second flow path and the third flow path.

2. The heating device according to claim 1, The heating device, wherein the third flow path is formed at a position more inward than the second flow path.

3. The heating device according to claim 2, The heating device, wherein the third flow path is formed inside a second housing made of metal and embedded in the axial core member made of resin.

4. The heating device according to claim 1, The heating device, wherein the third flow path is formed at a position outside the first flow path.

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