JP7795589B2 - Heat exchange unit and cleaning device equipped with same - Google Patents

Description

This disclosure relates to a heat exchange unit used in fluid heating devices, powder heating devices, gas heating devices, oxygen sensors, soldering irons, etc., and a cleaning device equipped with the same.

Patent Document 1 discloses a heat exchange unit for use in a fluid heating device, which consists of a cylindrical ceramic heater inserted into a case having an internal fluid flow path and an outlet that connects the fluid flow path to the outside. The fluid is heated both inside and outside the ceramic heater and flows out through the outlet of the case to the outside.

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 contained in the ceramic heater. As a result, the heat exchange unit described in Patent Document 1 may not be able to effectively heat a fluid.

Japanese Patent Application Laid-Open No. 2014-228252

A heat exchange unit according to one aspect of the present disclosure comprises a heater including a cylindrical ceramic body extending in the longitudinal direction and open at both ends, a meandering heating resistor embedded in the ceramic body and extending from one longitudinal end of the ceramic body to 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 end of the ceramic body, and a flange having a hole through which the ceramic body is inserted and bonded to the outer peripheral surface of the ceramic body near the other end via a bonding material, and a cylindrical case having one end closed and the other end open, and the open 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; 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 connects the second space with 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 areas that overlap with the bonding material.

In addition, one aspect of the heat exchange unit of the present disclosure includes a heater including a cylindrical ceramic body extending in the longitudinal direction and open at both ends, a meandering heating resistor embedded in the ceramic body and extending from one longitudinal end of the ceramic body toward the other 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 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 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 that 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 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 in the area that overlaps with the bonding material.

One aspect of the cleaning device disclosed herein is characterized in that it includes the heat exchange unit described above, and the fluid that flows through the flow path and is heated by the heater is discharged to the outside through the outlet.

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

Embodiments of the heat exchange unit of the present disclosure are described in detail below with reference to the drawings.

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

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.

The ceramic body 5 is a cylindrical member extending in the longitudinal direction (left-right direction in Figure 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 be in the shape of a triangular cylinder, a square cylinder, a cylinder, an elliptical cylinder, or any other shape. In this embodiment, the ceramic body 5 is cylindrical, as shown in Figures 1A and 1B, for example.

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 from the viewpoints of oxidation resistance and ease of manufacture. Silicon nitride can be used from the viewpoints of high strength, high toughness, high insulation, and excellent heat resistance. Aluminum nitride can be used from the viewpoint of 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 .

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 metallic material. Examples of metallic materials used for the coating layer include silver, gold, copper, nickel, etc. 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.

In this embodiment, as shown in Figures 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, with both ends open. The surface layer portion 5b is disposed on the outer peripheral surface of the core material 5a. The surface layer portion 5b may cover the entire outer peripheral surface of the core material 5a, or may cover only a portion of the outer peripheral 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.

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, leaving a portion of the outer peripheral surface of the core material 5a exposed. 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.

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 of the ceramic body 5 to the other end 5e. 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 surface of the core material 5a.

The heating resistor 6 is made of a conductive material primarily composed of a high-melting-point metal. Examples of conductive materials used for the heating resistor 6 include conductive materials primarily composed of tungsten, molybdenum, or rhenium. 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, for example, as follows: width 0.3 mm to 2 mm, thickness 0.01 mm to 0.1 mm, and total length 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 and the voltage applied to the heating resistor 6.

The heating resistor 6 has a conductor pattern that repeatedly folds 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 conductor pattern including multiple straight portions 6a and multiple folded portions 6b. The multiple straight 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 straight portions 6a. The folded portions 6b may be linear as shown in Figures 1B and 2B, or may be curved. The cross section of the heating resistor 6 may be circular, elliptical, rectangular, or other shapes.

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

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, for example, 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 end connected to the heating resistor 6.

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

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.

The through conductor 8 is disposed inside the ceramic body 5 and extends radially through the ceramic body 5. In this embodiment, the through conductor 8 penetrates radially through the surface layer 5b of the ceramic body. 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.

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

The electrode pad 9 is disposed on the outer peripheral surface of the ceramic body 5. The electrode pad 9 covers the end face of the through conductor 8 that is exposed on the outer peripheral surface 5g of the ceramic body 5. A lead terminal is joined to the electrode pad 9, and the electrode pad 9 is electrically connected to an external circuit (external power supply) via the lead terminal. The electrode pad 9 is made of a conductive material, such as tungsten or molybdenum. The outer surface of the electrode pad 9 may also be provided with a plating layer made of, for example, nickel-boron or gold. The electrode pad 9 has a thickness of, for example, 10 μm to 300 μm, and a length and width of 1 mm to 10 mm.

As shown in Figure 2A, the heater 3 further includes a metal layer 11 and a flange 12.

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.

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, thereby increasing the bonding strength between the ceramic body 5 and the flange 12.

The flange 12 is an annular member made of, for example, a metal material. The flange 12 is a member that makes it easy to attach 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 that can be used for the flange 12 include stainless steel and iron-nickel-cobalt alloys. From the perspective of corrosion resistance, stainless steel can be used. The surface of the flange 12 may also be coated with a plating layer primarily composed of metals such as nickel, tin, or gold, thereby improving the corrosion resistance of the flange 12.

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, when viewed in a cross section including the longitudinal direction of the ceramic body 5, as shown in Figure 2A, for example, the flange 12 has two bends midway from the inner periphery to the outer periphery.

The first portion 12a of the flange 12 is joined to the metal layer 11 via a joining material 13. Any material suitable for joining the metal layer 11 and the flange 12 can be used as the joining material 13. In this embodiment, a brazing material such as silver solder or silver-copper solder is used as the joining material 13.

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.

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, square, cylindrical, elliptical, or 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 a 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.

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 portion 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.

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 located on 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.

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, up to the 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 through the outlet 4b. Therefore, the heat exchange unit 1 of this embodiment can effectively heat the fluid to be heated.

Next, we will describe other examples of embodiments of the heat exchange unit of the present disclosure.

Figure 3A is a cross-sectional view showing another example of an embodiment of the heat exchanger unit of the present disclosure, and Figure 3B is an exploded view of the ceramic body in the heat exchanger unit shown in Figure 3A. The cross-sectional view shown in Figure 3A corresponds to the cross-sectional view shown in Figure 2A, and the exploded view shown in Figure 3B corresponds to the exploded view shown in Figure 2B. Note that Figure 3A shows the through conductors and electrode pads schematically, and the positions of the through conductors and electrode pads in Figure 3A are not accurately depicted. Also, in Figure 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 a similar configuration. Therefore, similar components are designated by the same reference numerals as in heat exchanger unit 1, and detailed description thereof will be omitted.

The heat exchange unit 1A of this embodiment is configured so 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. This configuration allows the fluid to be heated by the heating resistor 6 in the entire area near the outlet 4b. Therefore, the heat exchange unit 1A of this embodiment can effectively heat the fluid.

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

In the heat exchange unit 1B of this embodiment, the heating resistor 6 is configured to extend to the 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 throughout the entire 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 of the outlet 4b can be stabilized.

The heating resistor 6 may extend further 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 throughout the entire first space 10a and second space 10b. Furthermore, the flange 12 and the fluid in contact with the flange 12 can be heated by the heating resistor 6, preventing heat from the fluid from escaping to the outside via the flange 12. In this way, extending the heating resistor 6 to a portion close to the opening 4a effectively heats the fluid and stabilizes the temperature of the fluid flowing out of the outlet 4b.

Figure 5 is a cross-sectional view showing another example of an embodiment of the heat exchange unit of the present disclosure. The cross-sectional view shown in Figure 5 corresponds to a transverse cross-sectional view of the heat exchange unit when cut along the section line A-A shown in Figure 2A, the section line B-B shown in Figure 3A, and the section line C-C shown in Figure 4A. The heat exchange unit 1C of this embodiment differs from the heat exchange units 1, 1A, and 1B described above in terms of the configuration of the flange 12, but otherwise has the same configuration. Therefore, similar components are assigned the same reference numerals as those of the heat exchange units 1, 1A, and 1B, and detailed description thereof will be omitted.

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 easier to align the heat exchange unit with the external device when attaching the heat exchange unit to the external device.

As shown in FIG. 5, the protrusion 12e may be located on the opposite side of the outlet 4b from 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, 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 in a cross section perpendicular to the longitudinal direction of the ceramic body 5, 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°.

Figure 6 is a cross-sectional view showing another example of an embodiment of the heat exchange unit of the present disclosure. The cross-sectional view shown in Figure 6 corresponds to a transverse cross-sectional view of the heat exchange unit when cut along the section line A-A shown in Figure 2A, the section line B-B shown in Figure 3A, and the section line C-C shown in Figure 4A. The heat exchange unit 1D of this embodiment differs from the heat exchange 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, similar components are assigned the same reference numerals as those of the heat exchange units 1, 1A, and 1B, and detailed description thereof will be omitted.

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 mentioned above, the heating resistor 6 is not provided on the exposed outer 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. For example, as shown in Figure 6, in a cross section perpendicular to the longitudinal direction of the ceramic body 5, if an imaginary line L1 connects the centroid C1 of the ceramic body 5 to the centroid C2 of the outlet 4b, and an imaginary line L3 connects the centroid C1 of the ceramic body 5 to the centroid C4 of the recessed region 5h, the angle β formed by L1 and L3 should be in the range of 0° to 90°. Here, the recessed region 5h refers to the region defined by the imaginary outer peripheral surface 5g of the ceramic body 5 when the outer peripheral surface 5g is virtually extended in the circumferential direction of the ceramic body 5 and the inner surface of the recess 5c.

Figure 7 is a cross-sectional view showing another example of an embodiment of the heat exchange unit of the present disclosure. The cross-sectional view shown in Figure 7 corresponds to the cross-sectional views shown in Figures 2A, 3A, and 4A. Note that Figure 7 shows the through conductors and electrode pads schematically, and the positions of the through conductors and electrode pads in Figure 7 are not accurately depicted. Furthermore, heat exchange unit 1E of this embodiment differs from the above-described heat exchange units 1, 1A, 1B, 1C, and 1D in the configuration of outlet 4b, but otherwise has the same configuration. Therefore, similar components are assigned the same reference symbols as heat exchange units 1, 1A, 1B, 1C, and 1D, and detailed descriptions are omitted.

As shown in FIG. 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 fluid from accumulating in the area 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 undesirable 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.

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

First, an alumina ceramic green sheet is prepared as the surface layer 5b of the ceramic body 5. The green sheet _is primarily composed 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 formed on the surface of the alumina ceramic green sheet. Methods for forming this predetermined pattern include screen printing, transfer printing, resistor embedding, and other methods such as etching metal foil or embedding 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 be formed using separate methods.

Next, on the side of the ceramic green sheet opposite the side on which the heating resistor 6 and lead conductor 7 are formed, a pattern that will become the electrode pad 9 and metal layer 11 is formed in a predetermined pattern shape, similar to the formation of the heating resistor 6 and lead conductor 7. The ceramic green sheet is also drilled with holes to form the through conductors 8 that electrically connect the lead conductors 7 and electrode pads 9, and is filled with a conductive paste that will become the through conductors 8. The heating resistor 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.

Separately, a cylindrical alumina ceramic molded body is formed by extrusion molding to form the core material 5a of the ceramic body 5. The aforementioned alumina ceramic green sheet is wrapped around this cylindrical alumina ceramic molded body, and an adhesion liquid containing alumina ceramic of the same composition dispersed therein is applied to adhere the body to obtain an alumina-based integral molded body that will become the ceramic body 5. When wrapping the alumina ceramic green sheet around the alumina ceramic molded body, a predetermined area of the outer periphery of the alumina ceramic molded body is prevented from being covered by the alumina ceramic green sheet, thereby obtaining an alumina-based integral molded body having a groove that will become the recess 5c. The resulting alumina-based integral molded body is fired in a reducing atmosphere (nitrogen atmosphere) at 1500 to 1600°C, causing the alumina-based integral molded body to shrink, resulting in the production of an alumina-based integral sintered body (ceramic body 5).

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, or barrel plating.

The flange 12 can be produced by cutting, punching, pressing, etc., a stainless steel plate 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.

Next, the ceramic body 5 is set in the jig and aligned so that the hole 12d in the flange 12 overlaps the metal layer 11 of the ceramic body 5. Then, using the joining material 13, the ceramic body 5 is brazed at a temperature of approximately 1000°C in a furnace with a reducing atmosphere.

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.

Next, we will describe one example of an embodiment of the cleaning device disclosed herein.

The cleaning device of this embodiment includes the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E described above. The cleaning device is configured to discharge 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 the opening on the other end 5e 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. By including the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E, the cleaning device of this embodiment can effectively heat the fluid.

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 without departing from the spirit of the present disclosure. It goes without saying that all or part of the components of each of the above-described embodiments can be combined as appropriate, provided that they are not inconsistent.

REFERENCE SIGNS LIST 1, 1A, 1B, 1C, 1D, 1E Heat exchange unit 3 Heater 4 Case 4a Opening 4b Outlet 4c Inner circumferential surface 5 Ceramic body 5a Core material 5b Surface layer portion 5c Recessed portion 5d, 5e End portion 5f Inner circumferential surface 5g Outer circumferential surface 5h Recessed region 6 Heating resistor 6a Linear portion 6b Folded portion 7 Lead conductor 8 Penetrating conductor 9 Electrode pad 10 Flow path 10a First space 10b Second space 11 Metal layer 12 Flange 12a First portion 12b Second portion 12c Third portion 12d Hole 12e Protrusion 13 Bonding material

Claims (8)

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