Heat exchange unit and cleaning device equipped with same

Abstract

To provide a heat exchange unit used for a fluid heating apparatus, a powder heating apparatus, a gas heating apparatus, a soldering iron, etc., and a washing device with the same.SOLUTION: A heat exchange unit comprises: a heater including a cylindrical ceramic body, which extends in a length direction and has both the ends opened, and a heating resistive body which is embedded in the ceramic body and extends from one end of the ceramic body to the other end in the length direction; and a cylindrical case which has one end closed and the other end opened. In the case, the heater is inserted into an opening of the opened other end, and a portion closer to the one end of the ceramic body is stored. A passage of a fluid is formed by communicating between a first space defined by an inner peripheral surface of the ceramic body and a second space defined by an outer peripheral surface of the ceramic body and an inner peripheral surface of the case. The case includes an outflow port communicating between the second space and the outside, and a plurality of folded portions in the heating resistive body is positioned in a portion overlapping with a boundary between the heating resistive body and a lead-out conductor.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present disclosure relates to a heat exchange unit used in a fluid heating device, a powder heating device, a gas heating device, an oxygen sensor, a soldering iron, etc., and a cleaning device equipped with the same. [Background technology]

[0002] Patent Document 1 discloses a heat exchange unit used in a fluid heating device, which comprises a cylindrical ceramic heater inserted into a case having a fluid flow path therein and an outlet that connects the fluid flow path to the outside, and in which the fluid is heated inside and outside the ceramic heater and flows out from the outlet of the case to the outside.

[0003] There is a need to provide a heat exchange unit that can effectively heat an object to be heated. Patent Document 1 does not disclose the specific configuration of the heating resistor included in the ceramic heater. Therefore, the heat exchange unit described in Patent Document 1 may not be able to effectively heat a fluid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-228252 Summary of the Invention

[0005] A heat exchange unit according to one aspect of the present disclosure includes a heater including a cylindrical ceramic body extending in the longitudinal direction and having both ends open, a meandering heating resistor embedded in the ceramic body and extending from one longitudinal end of the ceramic body toward the other longitudinal end and including a plurality of linear portions and a plurality of folded portions, a lead conductor connected to the heating resistor and extending toward the other longitudinal end of the ceramic body, and a flange having a hole through which the ceramic body is inserted and joined to an outer peripheral surface of the ceramic body near the other longitudinal end via a joining material, and a cylindrical case having one end closed and the other end open, the open end the heater is inserted into the opening at the other end, and the case houses at least a portion of the ceramic body near one end, wherein a first space defined by the inner peripheral surface of the ceramic body is connected to a second space defined by the outer peripheral surface of the ceramic body and the inner peripheral surface of the case, the first space and the second space form a fluid flow path, the case has an outlet that connects the second space to the outside, the heater is inserted into the case so that the flange closes the opening of the case, and multiple folded portions of the heating resistor are located in the area that overlaps with the bonding material.

[0006] A heat exchange unit according to one aspect of the present disclosure includes a heater including a cylindrical ceramic body extending in the longitudinal direction and having both ends open, a meandering heating resistor embedded in the ceramic body and extending from one longitudinal end of the ceramic body toward the other longitudinal end and including a plurality of linear portions and a plurality of folded portions, a lead conductor connected to the heating resistor and extending toward the other longitudinal end of the ceramic body, and a flange having a hole through which the ceramic body is inserted and joined to the outer peripheral surface of the ceramic body near the other longitudinal end via a joining material, and a cylindrical case having one end closed and the other end open, the heater is inserted into the opening at the other end of the ceramic body, and a case accommodating at least a portion of the ceramic body near one end, wherein a first space defined by the inner peripheral surface of the ceramic body communicates with a second space defined by the outer peripheral surface of the ceramic body and the inner peripheral surface of the case, the first space and the second space form a fluid flow path, the case has an outlet that communicates the second space with the outside, the heater is inserted into the case so that the flange closes the opening of the case, and the boundary between the heating resistor and the lead conductor is located at the portion that overlaps with the bonding material.

[0007] A cleaning device according to one aspect of the present disclosure includes the heat exchange unit described above, and is characterized in that the fluid heated by the heater and flowing through the flow path is discharged to the outside through the outlet. [Brief explanation of the drawings]

[0008] The objects, features, and advantages of the present disclosure will become more apparent from the following detailed description and drawings. [Figure 1A] 1 is a perspective view illustrating an example of an embodiment of a heat exchange unit of the present disclosure. [Figure 1B] 1B is a perspective view showing an example of an embodiment of a heat exchange unit of the present disclosure, taken from a different perspective than FIG. 1A. FIG. [Figure 2A] FIG. 1 is a cross-sectional view showing an example of an embodiment of a heat exchange unit of the present disclosure. [Figure 2B]2B is a development view of a ceramic body in the heat exchange unit shown in FIG. 2A. FIG. [Figure 3A] FIG. 10 is a cross-sectional view showing another example of an embodiment of a heat exchange unit of the present disclosure. [Figure 3B] 3B is a development view of a ceramic body in the heat exchange unit shown in FIG. 3A. FIG. [Figure 4A] FIG. 10 is a cross-sectional view showing another example of an embodiment of a heat exchange unit of the present disclosure. [Figure 4B] FIG. 4B is a development view of a ceramic body in the heat exchange unit shown in FIG. 4A. [Figure 5] FIG. 10 is a cross-sectional view showing another example of an embodiment of a heat exchange unit of the present disclosure. [Figure 6] FIG. 10 is a cross-sectional view showing another example of an embodiment of a heat exchange unit of the present disclosure. [Figure 7] FIG. 10 is a cross-sectional view showing another example of an embodiment of a heat exchange unit of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the heat exchange unit of the present disclosure will be described in detail with reference to the drawings.

[0010] FIG. 1A is a perspective view showing an example of an embodiment of a heat exchange unit of the present disclosure, FIG. 1B is a perspective view showing an example of an embodiment of a heat exchange unit of the present disclosure from a different perspective than FIG. 1A, FIG. 2A is a cross-sectional view showing an example of an embodiment of a heat exchange unit of the present disclosure, and FIG. 2B is an exploded view of a ceramic body in the heat exchange unit shown in FIG. 2A. Note that the case is omitted in FIGS. 1A and 1B. Note that FIG. 2A shows the through conductors and electrode pads schematically, and the positions of the through conductors and electrode pads in FIG. 2A are not accurately depicted. In FIGS. 1B and 2B, the heating resistor and lead conductor are indicated by hatching. In FIG. 2B, the surface of the surface layer of the ceramic body facing the core material is exploded.

[0011] The heat exchange unit 1 includes a heater 3 and a case 4. The heater 3 includes a ceramic body 5 and a heating resistor 6.

[0012] The ceramic body 5 is a cylindrical member extending in the longitudinal direction (left-right direction in FIG. 2A). One end (front end) 5d and the other end (rear end) 5e in the longitudinal direction of the ceramic body 5 are open. The ceramic body 5 may have a triangular cylindrical shape, a square cylindrical shape, a cylindrical shape, an elliptical cylindrical shape, or other shapes. In this embodiment, the ceramic body 5 is cylindrical, as shown in FIGS. 1A and 1B, for example.

[0013] The ceramic body 5 is made of an insulating ceramic material. Examples of insulating ceramic materials used for the ceramic body 5 include alumina, silicon nitride, and aluminum nitride. Alumina can be used because it has oxidation resistance and is easy to manufacture. Silicon nitride can be used because it has high strength, toughness, insulating properties, and heat resistance. Aluminum nitride can be used because it has excellent thermal conductivity. The ceramic body 5 may contain a compound of the metal element contained in the heating resistor 6. For example, when the heating resistor 6 contains tungsten or molybdenum, the ceramic body 5 may contain WSi2 or MoSi2.

[0014] At least one of the inner circumferential surface 5f and the outer circumferential surface 5g of the ceramic body 5 may be coated with a coating layer made of a metal material. Examples of metal materials used for the coating layer include silver, gold, copper, and nickel. An oxide film may be formed on the outer surface of the coating layer. By coating at least one of the inner circumferential surface 5f and the outer circumferential surface 5g of the ceramic body 5 with a coating layer, the corrosion resistance of the ceramic body 5 can be improved, and ultimately the durability of the heat exchange unit 1 can be increased.

[0015] In this embodiment, as shown in FIGS. 1A, 1B, and 2A, the ceramic body 5 has a core material 5a and a surface layer portion 5b. The core material 5a is a cylindrical member extending in the longitudinal direction of the ceramic body 5, and both ends are open. The surface layer portion 5b is disposed on the outer circumferential surface of the core material 5a. The surface layer portion 5b may cover the entire outer circumferential surface of the core material 5a, or may cover only a portion of the outer circumferential surface of the core material 5a. In this embodiment, both ends of the core material 5a are not covered by the surface layer portion 5b and are exposed from the surface layer portion 5b. The core material 5a has, for example, a total length in the longitudinal direction of the ceramic body 5 of 30 mm to 150 mm, an outer diameter of 10 mm to 20 mm, and an inner diameter of 8 mm to 18 mm. The surface layer portion 5b has, for example, a total length in the longitudinal direction of the ceramic body 5 of 28 mm to 148 mm and a thickness of 0.2 mm to 1 mm.

[0016] The ceramic body 5 has a recess 5c extending in the longitudinal direction on its outer peripheral surface 5g. As shown in Figures 1A and 1B, the recess 5c is formed by the surface layer 5b not covering the entire outer peripheral surface of the core material 5a, but rather exposing a portion of the outer peripheral surface of the core material 5a. The recess 5c may be provided over the entire length of the surface layer 5b in the longitudinal direction of the ceramic body 5, or may be provided only in a portion of the surface layer 5b in the longitudinal direction of the ceramic body 5.

[0017] The heating resistor 6 is a conductive wire- or strip-shaped member. The heating resistor 6 generates heat when a current flows through it, and heats the object to be heated via the ceramic body 5. The heating resistor 6 is embedded in the ceramic body 5 and extends from one end 5d to the other end 5e of the ceramic body 5. In this embodiment, as shown in FIG. 1B, for example, the heating resistor 6 is disposed between the core material 5a and the surface layer 5b, and is not disposed on the exposed outer peripheral surface of the core material 5a.

[0018] The heating resistor 6 is made of a conductive material containing a high-melting-point metal as its main component. Examples of conductive materials used for the heating resistor 6 include conductive materials containing tungsten, molybdenum, or rhenium as its main component. The heating resistor 6 may also contain the material from which the ceramic body 5 is formed. The dimensions of the heating resistor 6 can be set to, for example, a width of 0.3 mm to 2 mm, a thickness of 0.01 mm to 0.1 mm, and a total length of 500 mm to 5000 mm. The dimensions of the heating resistor 6 are set appropriately depending on the heating temperature of the heating resistor 6, the voltage applied to the heating resistor 6, and the like.

[0019] The heating resistor 6 has a conductive pattern that is repeatedly folded back and forth between one end 5d and the other end 5e along the circumferential direction of the ceramic body 5. In other words, the heating resistor 6 has a meandering conductive pattern including multiple linear portions 6a and multiple folded portions 6b. The multiple linear portions 6a extend along the longitudinal direction of the ceramic body 5 and are arranged side by side with gaps between them. The multiple folded portions 6b extend along the circumferential direction of the ceramic body 5 when viewed in a cross section perpendicular to the longitudinal direction of the ceramic body 5, connecting the ends of adjacent linear portions 6a. The folded portions 6b may be linear as shown in FIGS. 1B and 2B or curved. The cross section of the heating resistor 6 may be circular, elliptical, rectangular, or other shapes.

[0020] The ceramic body 5 further includes a pair of lead conductors 7 , a through conductor 8 , and an electrode pad 9 .

[0021] The lead conductors 7 are linear or strip-shaped members extending in the longitudinal direction of the ceramic body 5. As shown in FIG. 2A, the lead conductors 7 are disposed between the core material 5a and the surface layer 5b. One end of each lead conductor 7 is connected to the heating resistor 6. The other end of each lead conductor 7 is located closer to the other end 5e of the ceramic body 5 than the other end connected to the heating resistor 6.

[0022] The lead conductor 7 is made of a conductive material containing a high-melting-point metal as its main component. Examples of conductive materials used for the lead conductor 7 include conductive materials containing tungsten, molybdenum, or rhenium as its main component. The lead conductor 7 may also contain the material from which the ceramic body 5 is formed.

[0023] The lead conductor 7 may have a lower resistance per unit length than the heating resistor 6. The lead conductor 7 may have a lower resistance per unit length than the heating resistor 6 by making the content of the material forming the ceramic body 5 less than that of the heating resistor 6. Alternatively, the lead conductor 7 may have a lower resistance per unit length than the heating resistor 6 by making the cross-sectional area of ​​the lead conductor 7 larger than that of the heating resistor 6.

[0024] The through conductor 8 is disposed inside the ceramic body 5 and extends in the radial direction of the ceramic body 5. In this embodiment, the through conductor 8 penetrates the surface layer portion 5b of the ceramic body in the radial direction. One end face of the through conductor 8 is connected to the other end of the lead conductor 7 that is not connected to the heating resistor 6, and the other end face of the through conductor 8 is exposed to the outer peripheral surface 5g of the ceramic body 5.

[0025] The through conductor 8 is made of a conductive material containing a high-melting-point metal as its main component. Examples of conductive materials used for the through conductor 8 include conductive materials containing tungsten, molybdenum, rhenium, or the like as its main component. The through conductor 8 may also contain the material from which the ceramic body 5 is formed.

[0026] The electrode pads 9 are disposed on the outer peripheral surface of the ceramic body 5. The electrode pads 9 cover the end faces of the through conductors 8 that are exposed on the outer peripheral surface 5g of the ceramic body 5. Lead terminals are joined to the electrode pads 9, and the electrode pads 9 are electrically connected to an external circuit (external power supply) via the lead terminals. The electrode pads 9 are made of a conductive material, and examples of the conductive material used for the electrode pads 9 include conductive materials made of tungsten, molybdenum, etc. Furthermore, the outer surface of the electrode pads 9 may be provided with a plating layer made of, for example, nickel-boron, gold, etc. The electrode pads 9 have a thickness of, for example, 10 μm to 300 μm, and a length and width of 1 mm to 10 mm.

[0027] The heater 3 further includes a metal layer 11 and a flange 12, as shown in FIG. 2A.

[0028] The metal layer 11 is disposed on the outer peripheral surface 5g of the ceramic body 5. As shown in Fig. 2A, for example, the metal layer 11 is located closer to one end 5d of the ceramic body 5 than the electrode pad 9. The metal layer 11 is made of a metal material such as tungsten or molybdenum.

[0029] The flange 12 is bonded to the outer surface of the metal layer 11 via a bonding material 13. A plating layer made of nickel, tin, gold, or the like may be formed on the outer surface of the metal layer 11. This improves the wettability between the metal layer 11 and the bonding material 13, and ultimately increases the bonding strength between the ceramic body 5 and the flange 12.

[0030] The flange 12 is an annular member made of, for example, a metal material. The flange 12 is a member for facilitating attachment of the heater 3 to an external device, and has a hole 12d through which the ceramic body 5 of the heater 3 is inserted. Examples of metal materials used for the flange 12 include stainless steel and iron-nickel-cobalt alloys. From the viewpoint of corrosion resistance, stainless steel can be used. In addition, the surface of the flange 12 may be coated with a plating layer mainly composed of a metal such as nickel, tin, or gold, thereby improving the corrosion resistance of the flange 12.

[0031] The flange 12 has a first portion 12a, a second portion 12b, and a third portion 12c. The first portion 12a rises vertically from the metal layer 11 toward the outer periphery. The second portion 12b extends from the outer periphery end of the first portion 12a toward the other end 5e of the ceramic body 5. The third portion 12c extends from the end of the second portion 12b on the other end 5e side toward the outer periphery. In other words, as shown in FIG. 2A, for example, when viewed in a cross section including the longitudinal direction of the ceramic body 5, the flange 12 has two bent portions midway from the inner periphery to the outer periphery.

[0032] The first portion 12a of the flange 12 is joined to the metal layer 11 via a joining material 13. As the joining material 13, any material for joining the metal layer 11 and the flange 12 can be used as appropriate. In this embodiment, as the joining material 13, a brazing material such as silver brazing or silver-copper brazing is used.

[0033] The length of the metal layer 11 in the longitudinal direction of the ceramic body 5 may be greater than the length of the first portion 12a in the longitudinal direction of the ceramic body 5. This allows the bonding material 13 to have a meniscus portion that extends from the metal layer 11 to the first portion 12a of the flange 12, thereby increasing the bonding strength between the ceramic body 5 and the flange 12 and ultimately improving the durability of the heat exchange unit 1.

[0034] The case 4 of the heat exchange unit 1 is a cylindrical member with one end (front end) closed and the other end (rear end) open. The case 4 may be a triangular cylinder, a square cylinder, a cylindrical shape, an elliptical cylinder, or any other shape. In this embodiment, the case 4 is cylindrical. The ceramic body 5 and the case 4 may be arranged so that the axis of the ceramic body 5 coincides with the axis of the case 4. The case 4 is made of a resin material with excellent heat resistance. An example of the resin material used for the case 4 is fluororesin. The dimensions of the case 4 are, for example, a total length of 40 mm to 160 mm in the longitudinal direction of the ceramic body 5 and an inner diameter of 10 mm to 25 mm.

[0035] The heater 3 is inserted into the opening 4a at the other open end of the case 4. The case 4 houses a portion of the ceramic body 5 near one end 5d. The heater 3 is inserted into the case 4 by press-fitting a part of the second portion 12b of the flange 12 into the opening 4a, as shown in FIG. 2A, for example. The second portion 12b may be press-fitted into the opening 4a of the case 4 via an O-ring.

[0036] In the heat exchange unit 1, a first space 10a defined by the inner circumferential surface 5f of the ceramic body 5 communicates with a second space 10b defined by the outer circumferential surface 5g of the ceramic body 5 and the inner circumferential surface 4c of the case 4, forming a flow path 10 through which the fluid to be heated flows. The case 4 also has an outlet 4b that connects the second space 10b with the outside. The outlet 4b is an opening for allowing the fluid heated by the heater 3 to flow out. As shown in FIG. 2A, for example, the outlet 4b is provided in a portion of the side wall of the case 4 near the other end 5e of the ceramic body 5. The outlet 4b has an inner diameter of, for example, 1 mm to 5 mm.

[0037] In the heat exchange unit 1 of this embodiment, the heating resistor 6 extends from one end 5d of the ceramic body 5 toward the other end 5e to a portion of the ceramic body 5 facing the outlet 4b. As a result, the fluid flowing through the flow path 10 is heated by the heating resistor 6 until just before it flows out from the outlet 4b to the outside. Therefore, the heat exchange unit 1 of this embodiment can effectively heat the fluid to be heated.

[0038] Next, another embodiment of the heat exchange unit of the present disclosure will be described.

[0039] FIG. 3A is a cross-sectional view showing another example of an embodiment of a heat exchanger unit according to the present disclosure, and FIG. 3B is an exploded view of the ceramic body in the heat exchanger unit shown in FIG. 3A. The cross-sectional view shown in FIG. 3A corresponds to the cross-sectional view shown in FIG. 2A, and the exploded view shown in FIG. 3B corresponds to the exploded view shown in FIG. 2B. Note that FIG. 3A shows the through conductors and electrode pads schematically, and the positions of the through conductors and electrode pads in FIG. 3A are not precisely illustrated. Also, in FIG. 3B, the heating resistors and lead conductors are indicated by hatching. The heat exchanger unit 1A of this embodiment differs from the heat exchanger unit 1 described above in the configuration of the heating resistor 6, but otherwise has the same configuration. Therefore, the same reference numerals as those in the heat exchanger unit 1 are used for the same components, and detailed description thereof will be omitted.

[0040] The heat exchange unit 1A of this embodiment is configured such that the heating resistor 6 extends further toward the other end of the ceramic body 5 than the portion of the ceramic body 5 facing the outlet 4b. With this configuration, the fluid can be heated by the heating resistor 6 in the entire region near the outlet 4b. Therefore, the heat exchange unit 1A of this embodiment can effectively heat the fluid.

[0041] FIG. 4A is a cross-sectional view showing another example of an embodiment of a heat exchanger unit according to the present disclosure, and FIG. 4B is an exploded view of the ceramic body in the heat exchanger unit shown in FIG. 4A. The cross-sectional view shown in FIG. 4A corresponds to the cross-sectional views shown in FIGS. 2A and 3A, and the exploded view shown in FIG. 4B corresponds to the exploded views shown in FIGS. 2B and 3B. Note that FIG. 4A shows the through conductors and electrode pads schematically, and the positions of the through conductors and electrode pads in FIG. 4A are not precisely illustrated. Also, in FIG. 4B, the heating resistors and lead conductors are indicated by hatching. The heat exchanger unit 1B of this embodiment differs from the heat exchanger units 1 and 1A described above in the configuration of the heating resistor 6, but otherwise has the same configuration. Therefore, the same reference numerals as those in the heat exchanger units 1 and 1A are used for the same components, and detailed description thereof will be omitted.

[0042] In the heat exchange unit 1B of this embodiment, the heating resistor 6 is configured to extend to a portion of the ceramic body 5 that is close to the flange 12. With this configuration, the fluid can be heated by the heating resistor 6 in the entire region of the first space 10a and the second space 10b. Therefore, with the heat exchange unit 1B of this embodiment, the fluid can be effectively heated and the temperature of the fluid flowing out from the outlet 4b can be stabilized.

[0043] The heating resistor 6 may further extend to a portion of the ceramic body 5 close to the opening 4a of the case 4. This allows the fluid to be heated by the heating resistor 6 in the entire region of the first space 10a and the second space 10b. Furthermore, since the flange 12 and the fluid in contact with the flange 12 can be heated by the heating resistor 6, it is possible to prevent heat from the fluid from escaping to the outside via the flange 12. In this way, by extending the heating resistor 6 to a portion close to the opening 4a, the fluid can be effectively heated and the temperature of the fluid flowing out from the outlet 4b can be stabilized.

[0044] Fig. 5 is a cross-sectional view showing another example of an embodiment of a heat exchanger unit according to the present disclosure. The cross-sectional view shown in Fig. 5 corresponds to a transverse cross-sectional view of the heat exchanger unit when cut along the section line AA shown in Fig. 2A, the section line BB shown in Fig. 3A, and the section line CC shown in Fig. 4A. A heat exchanger unit 1C of this embodiment is different from the heat exchanger units 1, 1A, and 1B described above in terms of the configuration of the flange 12, but otherwise has the same configuration. Therefore, the same reference numerals as those of the heat exchanger units 1, 1A, and 1B are used for the similar configurations, and detailed description thereof will be omitted.

[0045] In the heat exchange unit 1C of this embodiment, a protrusion 12e that protrudes radially is provided on the outer periphery of the third portion 12c of the flange 12. This makes it easy to align the heat exchange unit with the external device when attaching the heat exchange unit to the external device.

[0046] As shown in FIG. 5, the protrusion 12e may be located on the opposite side of the outlet 4b with respect to the centroid C1 of the ceramic body 5 when viewed in a cross section perpendicular to the longitudinal direction of the ceramic body 5. In this embodiment, the protrusion 12e, which easily releases heat to the outside, is located on the opposite side of the outlet 4b, thereby suppressing a temperature drop in the fluid flowing near the outlet 4b. Therefore, the heat exchange unit 1C of this embodiment can effectively heat the fluid. Note that, for example, as shown in FIG. 5, in a cross section perpendicular to the longitudinal direction of the ceramic body 5, if an imaginary line connecting the centroid C1 of the ceramic body 5 and the centroid C2 of the outlet 4b is defined as L1 and an imaginary line connecting the centroid C1 of the ceramic body 5 and the centroid C3 of the protrusion 12e is defined as L2, the angle α formed by L1 and L2 may be in the range of 0° to 90°.

[0047] Fig. 6 is a cross-sectional view showing another example of an embodiment of a heat exchanger unit according to the present disclosure. The cross-sectional view shown in Fig. 6 corresponds to a transverse cross-sectional view of the heat exchanger unit taken along the section line AA shown in Fig. 2A, the section line BB shown in Fig. 3A, and the section line CC shown in Fig. 4A. A heat exchanger unit 1D of this embodiment differs from the heat exchanger units 1, 1A, and 1B described above in terms of the relative positions of the outlet 4b and the recess 5c, but otherwise has the same configuration. Therefore, the same reference numerals as those of the heat exchanger units 1, 1A, and 1B are used for similar configurations, and detailed description thereof will be omitted.

[0048] In the heat exchange unit 1D of this embodiment, when viewed in a cross section perpendicular to the longitudinal direction of the ceramic body 5, the recess 5c is located on the opposite side of the ceramic body 5 from the portion facing the outlet 4b. As described above, the heating resistor 6 is not provided on the exposed outer peripheral surface of the core material 5a, which forms the bottom surface of the recess 5c. Therefore, the amount of heat generated in the region near the recess 5c of the heater 3 may be less than the amount of heat generated in other regions. In this embodiment, because the recess 5c is located on the opposite side of the ceramic body 5 from the portion facing the outlet 4b, a decrease in the temperature of the fluid flowing near the outlet 4b can be suppressed. Therefore, the heat exchange unit 1D of this embodiment can effectively heat the fluid. 6, in a cross section perpendicular to the longitudinal direction of ceramic body 5, if an imaginary line L1 connects centroid C1 of ceramic body 5 to centroid C2 of outlet 4b and an imaginary line L3 connects centroid C1 of ceramic body 5 to centroid C4 of recessed region 5h, the angle β formed by L1 and L3 may be in the range of 0° to 90°. Here, recessed region 5h refers to the region defined by an imaginary outer peripheral surface 5g of ceramic body 5 when the outer peripheral surface 5g is virtually extended in the circumferential direction of ceramic body 5 and the inner surface of recess 5c.

[0049] Fig. 7 is a cross-sectional view showing another example of an embodiment of a heat exchanger unit according to the present disclosure. The cross-sectional view shown in Fig. 7 corresponds to the cross-sectional views shown in Figs. 2A, 3A, and 4A. Note that Fig. 7 shows the through conductors and electrode pads in a schematic manner, and the positions of the through conductors and electrode pads in Fig. 7 are not accurately depicted. Furthermore, a heat exchanger unit 1E of this embodiment is different from the heat exchanger units 1, 1A, 1B, 1C, and 1D described above in terms of the configuration of the outlet 4b, but otherwise has the same configuration. Therefore, the same reference numerals as those of the heat exchanger units 1, 1A, 1B, 1C, and 1D are used for the similar configurations, and detailed description thereof will be omitted.

[0050] 7, the heat exchange unit 1E of this embodiment is configured so that the outlet 4b is close to the opening 4a. This configuration prevents the fluid from accumulating in the region between the outlet 4b and the flange 12 in the second space 10b, preventing the accumulating fluid from moving near the outlet 4b and causing undesired changes in the temperature of the fluid flowing out from the outlet 4b. This stabilizes the temperature of the fluid flowing out from the outlet 4b. Therefore, the heat exchange unit 1E of this embodiment can effectively heat the fluid.

[0051] Next, an example of a method for manufacturing the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E will be described. In this example, the ceramic body 5 is made of alumina ceramics.

[0052] First, an alumina ceramic green sheet is prepared as the surface layer 5b of the ceramic body 5. The green sheet is composed primarily of Al2O3, with SiO2, CaO, MgO, and ZrO2 adjusted to a total content of 10% by mass or less. A predetermined pattern for the heating resistor 6 and the lead conductor 7 is then formed on the surface of the alumina ceramic green sheet. This predetermined pattern can be formed by screen printing, transfer printing, resistor embedding, or other methods such as etching a metal foil or embedding a nichrome wire in a coil shape. Screen printing is often used from the standpoints of stable quality and reduced manufacturing costs. The heating resistor 6 and the lead conductor 7 may also be formed by separate methods.

[0053] Next, on the surface of the ceramic green sheet opposite to the surface on which the heating resistor 6 and the lead conductor 7 are formed, patterns that will become electrode pads 9 and metal layers 11 are formed in a predetermined pattern shape, in the same manner as the formation of the heating resistor 6 and the lead conductor 7. Furthermore, the ceramic green sheet is drilled with holes to form through conductors 8 that electrically connect the lead conductors 7 and the electrode pads 9, and the holes are filled with a conductive paste that will become the through conductors 8. The heating resistors 6, lead conductors 7, through conductors 8, and electrode pads 9 can be made of a conductive paste whose main component is a high-melting point metal such as tungsten, molybdenum, or rhenium.

[0054] On the other hand, a cylindrical alumina ceramic molded body that will become the core material 5a of the ceramic body 5 is molded by extrusion molding. The above-mentioned alumina ceramic green sheet is wrapped around this cylindrical alumina ceramic molded body, and an adhesion liquid in which alumina ceramics of the same composition is dispersed is applied to adhere the alumina ceramic to obtain an alumina ceramic integral molded body that will become the ceramic body 5. When the alumina ceramic green sheet is wrapped around the alumina ceramic molded body, a predetermined area on the outer surface of the alumina ceramic molded body is not covered by the alumina ceramic green sheet, thereby obtaining an alumina ceramic integral molded body having grooves that will become the recesses 5c. The obtained alumina ceramic integral molded body is fired in a reducing atmosphere (nitrogen atmosphere) at 1500 to 1600°C, whereby the alumina ceramic integral molded body shrinks, and an alumina ceramic integral sintered body (ceramic body 5) can be produced.

[0055] Next, plating is applied to the electrode pads 9 and metal layer 11 formed on the ceramic body 5. Common plating methods include nickel plating, gold plating, and tin plating. The plating method can be selected depending on the purpose, such as electroless plating, electrolytic plating, and barrel plating.

[0056] The flange 12 can be produced by subjecting a stainless steel plate to cutting, punching, pressing, etc. to form a shape having a first portion 12a, a second portion 12b, and a third portion 12c, as well as a hole 12d through which the ceramic body 5 is inserted.

[0057] Next, the ceramic body 5 is set in the jig and aligned so that the hole 12d of the flange 12 overlaps the metal layer 11 of the ceramic body 5, and brazing is performed using the joining material 13 at a temperature of about 1000°C in a furnace in a reducing atmosphere.

[0058] Next, an O-ring made of rubber or the like is attached to the outer peripheral surface of the second portion 12b of the flange 12. A resin case 4 is prepared, and the heater 3 with the O-ring attached is inserted into the case 4, thereby manufacturing the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E.

[0059] Next, an example of an embodiment of the cleaning device of the present disclosure will be described.

[0060] The cleaning device of this embodiment includes the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E. The cleaning device is configured to discharge a fluid heated by the heater 3, which flows through the flow path 10, to the outside via the outlet 4b. The fluid is, for example, water supplied from a water source such as a public water supply. The fluid flows into the first space 10a from an opening on the other end 5e side of the ceramic body 5, then flows into the second space 10b, and is discharged to the outside via the outlet 4b. The fluid is heated to a predetermined temperature by the heater 3 while passing through the flow path 10. The heated fluid is used, for example, for washing private parts of the human body. The cleaning device of this embodiment includes the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E, thereby enabling the fluid to be effectively heated.

[0061] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure. It goes without saying that all or part of the components constituting each of the above-described embodiments can be combined as appropriate within the scope of not contradicting each other. [Explanation of symbols]

[0062] 1, 1A, 1B, 1C, 1D, 1E Heat exchange unit 3 Heater 4 cases 4a aperture 4b Outlet 4c Inner surface 5. Ceramic body 5a Core material 5b Surface layer 5c Recess 5d, 5e End 5f Inner surface 5g outer surface 5h recessed area 6 Heating resistor 6a Straight section 6b Folded part 7 Lead conductor 8 Through conductor 9 Electrode Pads 10 Flow path 10a 1st space 10b 2nd space 11 Metal layer 12 flange 12a Part 1 12b Part 2 12c 3rd part 12d hole 12e Protrusion 13 Bonding material

Claims

1. a cylindrical ceramic body extending in a longitudinal direction and open at both ends; a meandering heating resistor embedded in the ceramic body, extending from one longitudinal end to the other longitudinal end of the ceramic body, and including a plurality of linear portions and a plurality of folded portions; a lead conductor connected to the heating resistor and extending toward the other end of the ceramic body; a flange having a hole through which the ceramic body is inserted and joined to an outer peripheral surface of the ceramic body near the other end thereof via a joining material; a heater including: a cylindrical case having one end closed and the other end open, the heater being inserted into the opening at the other end, and the case housing at least a portion of the ceramic body near the one end, a first space defined by an inner peripheral surface of the ceramic body communicates with a second space defined by an outer peripheral surface of the ceramic body and an inner peripheral surface of the case, and the first space and the second space form a flow path for a fluid; the case has an outlet that connects the second space to the outside, the heater is inserted into the case so that the flange closes the opening of the case, a plurality of folded portions of the heating resistor are located at portions overlapping the boundaries between the heating resistor and the lead conductors, the flange is a metal member, the joining material is a brazing material, A heat exchange unit characterized in that a metal layer is disposed on the outer peripheral surface of the ceramic body, and the flange is joined to the ceramic body via the metal layer.

2. A cylindrical ceramic body extending in a longitudinal direction and open at both ends; a meandering heating resistor embedded in the ceramic body, extending from one longitudinal end to the other longitudinal end of the ceramic body, and including a plurality of linear portions and a plurality of folded portions; a lead conductor connected to the heating resistor and extending toward the other end of the ceramic body; a flange having a hole through which the ceramic body is inserted and joined to an outer peripheral surface of the ceramic body near the other end thereof via a joining material; a heater including: a cylindrical case having one end closed and the other end open, the heater being inserted into the opening at the other end, and the case housing at least a portion of the ceramic body near the one end, a first space defined by an inner peripheral surface of the ceramic body communicates with a second space defined by an outer peripheral surface of the ceramic body and an inner peripheral surface of the case, and the first space and the second space form a flow path for a fluid; the case has an outlet that connects the second space to the outside, the heater is inserted into the case so that the flange closes the opening of the case, a plurality of folded portions of the heating resistor are located at portions overlapping the boundaries between the heating resistor and the lead conductors, the flange is a metal member, the joining material is a brazing material, a metal layer is disposed on an outer peripheral surface of the ceramic body, and the flange is joined to the ceramic body via the metal layer; the bonding material has a meniscus portion extending from the metal layer to the flange, The heat exchange unit is characterized in that the meniscus portion is located on the one end side and the other end side of the ceramic body.

3. A cylindrical ceramic body extending in a longitudinal direction and having both ends open; a meandering heating resistor embedded in the ceramic body, extending from one longitudinal end to the other longitudinal end of the ceramic body, and including a plurality of linear portions and a plurality of folded portions; a lead conductor connected to the heating resistor and extending toward the other end of the ceramic body; a flange having a hole through which the ceramic body is inserted and joined to an outer peripheral surface of the ceramic body near the other end thereof via a joining material; a heater including: a cylindrical case having one end closed and the other end open, the heater being inserted into the opening at the other end, and the case housing at least a portion of the ceramic body near the one end, a first space defined by an inner peripheral surface of the ceramic body communicates with a second space defined by an outer peripheral surface of the ceramic body and an inner peripheral surface of the case, and the first space and the second space form a flow path for a fluid; the case has an outlet that connects the second space to the outside, the heater is inserted into the case so that the flange closes the opening of the case, a plurality of folded portions of the heating resistor are located at portions overlapping the boundaries between the heating resistor and the lead conductors, A heat exchange unit characterized in that the flange has a radially protruding convex portion on its outer periphery, and when viewed in a cross section perpendicular to the longitudinal direction, the convex portion is located on the opposite side of the outlet from the centroid of the ceramic body.

4. A cylindrical ceramic body extending in a longitudinal direction and open at both ends; a meandering heating resistor embedded in the ceramic body, extending from one longitudinal end to the other longitudinal end of the ceramic body, and including a plurality of linear portions and a plurality of folded portions; a lead conductor connected to the heating resistor and extending toward the other end of the ceramic body; a flange having a hole through which the ceramic body is inserted and joined to an outer peripheral surface of the ceramic body near the other end thereof via a joining material; a heater including: a cylindrical case having one end closed and the other end open, the heater being inserted into the opening at the other end, and the case housing at least a portion of the ceramic body near the one end, a first space defined by an inner peripheral surface of the ceramic body communicates with a second space defined by an outer peripheral surface of the ceramic body and an inner peripheral surface of the case, and the first space and the second space form a flow path for a fluid; the case has an outlet that connects the second space to the outside, the heater is inserted into the case so that the flange closes the opening of the case, a plurality of folded portions of the heating resistor are located at portions overlapping the boundaries between the heating resistor and the lead conductors, the ceramic body has a recess on the outer circumferential surface extending in the longitudinal direction, A heat exchange unit characterized in that, when viewed in a cross section perpendicular to the longitudinal direction, the recess is located on the opposite side of the ceramic body from the portion facing the outlet.

5. 5. The heat exchange unit according to claim 1, wherein the content of the material forming the ceramic body in the lead conductor is less than that in the heating resistor.

6. 6. The heat exchange unit according to claim 1, wherein the heating resistor extends further toward the other end of the ceramic body than the outlet.

7. 7. The heat exchange unit according to claim 1, wherein the outlet of the case is located close to the opening of the case.

8. 8. A cleaning device comprising the heat exchange unit according to claim 1, wherein the fluid that flows through the flow path and is heated by the heater is discharged to the outside through the outlet.

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