JP7525569B2 - Heat exchange unit and cleaning device equipped with same - Google Patents

Description

This 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.

As a heat exchange unit used in a fluid heating device, Patent Document 1 discloses a heat exchange unit in which a cylindrical ceramic heater is inserted into a case having an internal fluid flow path and an outlet that connects the fluid flow path to the outside, heating the fluid inside and outside the ceramic heater and discharging it to the outside from the outlet of the case.

There is a demand for 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. Therefore, the heat exchange unit described in Patent Document 1 may not be able to effectively heat a fluid.

JP 2014-228252 A

A heat exchange unit according to one aspect of the present disclosure includes a heater including: 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 of the ceramic body toward the other longitudinal end of the ceramic body, and including a plurality of straight portions and a plurality of folded portions; a lead conductor connected to the heating resistor, extending toward the other longitudinal end of the ceramic body, and having a resistance value per unit length lower than that of the heating resistor ; and a flange having a hole through which the ceramic body is inserted and joined to an outer circumferential 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 being inserted into the opening of the other end that is open, and housing at least a portion of the ceramic body near one end, wherein a first space defined by an inner circumferential surface of the ceramic body communicates with a second space defined by an outer circumferential surface of the ceramic body and an inner circumferential surface of the case, the first space and the second space form a flow path for a fluid, the case has an outlet that communicates the second space with the outside, the heater is inserted into the case such that the flange closes the opening of the case,
The heating resistor is characterized in that the plurality of folded-back portions are located in portions overlapping with the bonding material.

Also, 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 straight portions and a plurality of folded portions; a lead conductor connected to the heating resistor, extending toward the other longitudinal end of the ceramic body and having a resistance value per unit length lower than that of the heating resistor ; 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 heater having one end closed and the other end open. The present invention is characterized in that the heater is inserted into the case so that the flange closes the opening of the case, the heater being inserted into the opening of the other end, and the case housing at least a portion of the ceramic body near one end, a first space defined by the inner surface of the ceramic body is connected to a second space defined by the outer surface of the ceramic body and the inner surface of the case, the first space and the second space form a flow path for a fluid, the case has an outlet connecting the second space to 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 portion overlapping with the bonding material.

A cleaning device according to one aspect of the present disclosure is characterized in that it includes the above-mentioned heat exchange unit, and the fluid that flows through the flow path and is heated by the heater is discharged to the outside via the outlet.

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

The following describes in detail an embodiment of the heat exchange unit of the present disclosure with reference to the drawings.

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

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 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 be in the shape of a triangular tube, a square tube, a cylinder, an elliptical tube, or other shape. In this embodiment, the ceramic body 5 is cylindrical, for example, as shown in FIGS. 1A and 1B.

The ceramic body 5 is made of an insulating ceramic material. Examples of the insulating ceramic material used in the ceramic body 5 include alumina, silicon nitride, and aluminum nitride. Alumina can be used from the viewpoint of oxidation resistance and ease of manufacture. Silicon nitride can be used from the viewpoint 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 peripheral surface 5f and the outer peripheral surface 5g of the ceramic body 5 may be coated with a coating layer made of a metal material. Examples of the metal material used for the coating layer include metal materials containing 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 peripheral surface 5f and the outer peripheral surface 5g of the ceramic body 5 with a coating layer, the corrosion resistance of the ceramic body 5 can be improved, and the durability of the heat exchange unit 1 can be increased.

In this embodiment, as shown in, for example, 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, and both ends are 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 part 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. For example, the core material 5a has 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. For example, the surface layer portion 5b has 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 the outer peripheral surface 5g. The recess 5c is formed by exposing a part of the outer peripheral surface of the core material 5a, rather than covering the entire outer peripheral surface of the core material 5a, as shown in, for example, FIGS. 1A and 1B. 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 part of the surface layer 5b in the longitudinal direction of the ceramic body 5.

The heating resistor 6 is a linear or strip-shaped member having electrical conductivity. 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 peripheral surface of the core material 5a.

The heating resistor 6 is made of a conductive material mainly composed of a high melting point metal. Examples of conductive materials used in the heating resistor 6 include conductive materials mainly 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 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 and the voltage applied to the heating resistor 6.

The heating resistor 6 has a conductor 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 conductor pattern including a plurality of straight portions 6a and a plurality of folded portions 6b. The plurality of straight portions 6a extend along the longitudinal direction of the ceramic body 5 and are arranged side by side with gaps between them. The plurality of 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, and connect 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 includes 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. The lead conductors 7 are disposed between the core material 5a and the surface layer 5b, as shown in FIG. 2A, for example. 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 one end connected to the heating resistor 6.

The lead-out conductor 7 is made of a conductive material mainly composed of a high melting point metal. Examples of conductive materials used in the lead-out conductor 7 include conductive materials mainly composed of tungsten, molybdenum, or rhenium. The lead-out 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 the surface layer 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-out 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 mainly composed of a high melting point metal. Examples of conductive materials used in the through conductor 8 include conductive materials mainly composed of 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 surface 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 source) via the lead terminal. The electrode pad 9 is made of a conductive material, and examples of the conductive material used in the electrode pad 9 include conductive materials made of tungsten, molybdenum, etc. In addition, the outer surface of the electrode pad 9 may be provided with a plating layer made of, for example, nickel-boron, gold, etc. 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.

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

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 can improve the wettability between the metal layer 11 and the bonding material 13, and can therefore increase 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 for making it easier 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 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 covered with a plating layer mainly composed of metals such as nickel, tin, and 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 other end 5e of the second portion 12b toward the outer periphery. In other words, the flange 12 has two bends on the way from the inner periphery to the outer periphery when viewed in a cross section including the longitudinal direction of the ceramic body 5, as shown in FIG. 2A, for example.

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, a brazing material such as silver brazing or silver-copper brazing is used as the joining material 13.

The metal layer 11 and the flange 12 may be such that the length of the metal layer 11 in the longitudinal direction of the ceramic body 5 is 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 thereby 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 tube, a square tube, a cylinder, an elliptical tube, 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 and the axis of the case 4 coincide with each other. 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.

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 pressing 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 pressed 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 communicates the second space 10b with the outside. The outlet 4b is an opening for discharging the fluid heated by the heater 3 to the outside. 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, as shown in FIG. 2A, for example. 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 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 it is about to flow out from the outlet 4b to the outside. Therefore, according to the heat exchange unit 1 of this embodiment, the fluid to be heated can be effectively heated.

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

3A is a cross-sectional view showing another example of an embodiment of the heat exchange unit of the present disclosure, and FIG. 3B is an expanded view of the ceramic body in the heat exchange 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 expanded view shown in FIG. 3B corresponds to the expanded view shown in FIG. 2B. Note that FIG. 3A shows the through conductors and electrode pads in a schematic manner, and the positions of the through conductors and electrode pads in FIG. 3A are not shown precisely. Also, in FIG. 3B, the heating resistors and the lead conductors are shown hatched. The heat exchange unit 1A of this embodiment is different from the heat exchange unit 1 described above in the configuration of the heating resistor 6, and the rest of the configuration is the same, so the same reference symbols as those of the heat exchange unit 1 are used for the similar configurations and detailed descriptions are omitted.

The heat exchange unit 1A of this embodiment is configured such that the heating resistor 6 extends beyond the portion of the ceramic body 5 that faces the outlet 4b toward the other end of the ceramic body 5. With this configuration, the fluid can 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 expanded 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 expanded view shown in Figure 4B corresponds to the expanded views shown in Figures 2B and 3B. Note that Figure 4A shows the through conductors and electrode pads in a schematic manner, and the positions of the through conductors and electrode pads in Figure 4A are not shown accurately. Also, in Figure 4B, the heating resistor and the lead conductor are shown with hatching. The heat exchange unit 1B of this embodiment is different from the above heat exchange units 1 and 1A in the configuration of the heating resistor 6, and the other configurations are similar, so the same reference symbols as those of the heat exchange units 1 and 1A are used for similar configurations and detailed descriptions are omitted.

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 close to the flange 12. With this configuration, the fluid can be heated by the heating resistor 6 in the entire area 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.

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 in the entire area 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 the heat of 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.

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 cutting line A-A shown in Figure 2A, the cutting line B-B shown in Figure 3A, and the cutting line C-C shown in Figure 4A. The heat exchange unit 1C of this embodiment is different from the heat exchange units 1, 1A, and 1B described above in terms of the configuration of the flange 12, but otherwise has a similar configuration. Therefore, similar configurations are given the same reference symbols as the heat exchange units 1, 1A, and 1B, and detailed descriptions are omitted.

In the heat exchange unit 1C of this embodiment, a protrusion 12e that protrudes in the radial direction 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 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 is likely to release heat to the outside, is located on the opposite side of the outlet 4b, so that the temperature drop of the fluid flowing near the outlet 4b can be suppressed. Therefore, according to the heat exchange unit 1C of this embodiment, the fluid can be effectively heated. 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 L1, and an imaginary line connecting the centroid C1 of the ceramic body 5 and the centroid C3 of the protrusion 12e is L2, the angle α between 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 cut line A-A shown in Figure 2A, the cut line B-B shown in Figure 3A, and the cut 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 the relative positions of the outlet 4b and the recess 5c, but otherwise has the same configuration. Therefore, the same reference symbols as those of the heat exchange units 1, 1A, and 1B are used for similar configurations, and detailed explanations are 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 part 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 that forms the bottom surface of the recess 5c. Therefore, the amount of heat generated in the area near the recess 5c of the heater 3 may be less than the amount of heat generated in other areas. In this embodiment, since the recess 5c is located on the opposite side of the ceramic body 5 from the part facing the outlet 4b, the temperature drop of the fluid flowing near the outlet 4b can be suppressed. Therefore, according to the heat exchange unit 1D of this embodiment, the fluid can be effectively heated. 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 connecting the centroid C1 of the ceramic body 5 and the centroid C2 of the outlet 4b is L1, and an imaginary line connecting the centroid C1 of the ceramic body 5 and the centroid C4 of the recessed region 5h is L3, the angle β between L1 and L3 may 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 in a schematic manner, and the positions of the through conductors and electrode pads in Figure 7 are not precisely illustrated. Also, the heat exchange unit 1E of this embodiment is different from the above heat exchange units 1, 1A, 1B, 1C, and 1D in the configuration of the outlet 4b, but otherwise has the same configuration. Therefore, the same reference symbols as those of the heat exchange units 1, 1A, 1B, 1C, and 1D are used for the similar configuration, and detailed description is 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 can prevent the fluid from accumulating in the area between the outlet 4b and the flange 12 in the second space 10b, and therefore prevents the accumulating fluid from moving to the vicinity of the outlet 4b and causing undesirable changes in the temperature of the fluid flowing out from the outlet 4b, thereby stabilizing 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 the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E will be described. In this example, an example in which the ceramic body 5 is made of alumina ceramics will be described.

First, an alumina ceramic green sheet _{is prepared as the surface layer 5b of the ceramic body 5, with Al2O3 as} the main component and _SiO2 , CaO, MgO, and _ZrO2 adjusted to be within 10 mass% in total. A predetermined pattern is formed on the surface of this alumina ceramic green sheet as the heating resistor 6 and the lead conductor 7. Methods for forming this predetermined pattern include screen printing, transfer, resistor embedding, and other methods such as forming a metal foil by etching, or forming a nichrome wire into a coil and embedding it. From the viewpoint of quality stability and suppression of manufacturing costs, the screen printing method is likely to be used. The heating resistor 6 and the lead conductor 7 may be formed by different forming methods.

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, a pattern that will become the electrode pad 9 and metal layer 11 is formed in a predetermined pattern shape, in the same manner as the formation of the heating resistor 6 and the lead conductor 7. In addition, the ceramic green sheet is drilled to form the through conductor 8 that electrically connects the lead conductor 7 and the electrode pad 9, and is filled with a conductive paste that will become the through conductor 8. The heating resistor 6, lead conductor 7, through conductor 8, and electrode pad 9 can be made of a conductive paste mainly composed of a high melting point metal such as tungsten, molybdenum, or rhenium.

On the other hand, a cylindrical alumina ceramic molded body is molded by extrusion molding to become the core material 5a of the ceramic body 5. 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 and adhered to obtain an alumina-based integral molded body that becomes the ceramic body 5. When the alumina ceramic green sheet is wrapped around the alumina ceramic molded body, a predetermined area of the outer periphery of the alumina ceramic molded body is not covered by the alumina ceramic green sheet, so that an alumina-based integral molded body having a groove that becomes the recess 5c can be obtained. The obtained alumina-based integral molded body is fired in a reducing atmosphere (nitrogen atmosphere) at 1500 to 1600, whereby the alumina-based integral molded body shrinks, and an alumina-based integral sintered body (ceramic body 5) can be produced.

Next, plating is applied to the electrode pads 9 and metal layer 11 formed on the ceramic body 5. Nickel plating, gold plating, tin plating, etc. are commonly used for plating. The plating method can be selected according to the purpose from electroless plating, electrolytic plating, barrel plating, etc.

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.

Next, the ceramic body 5 is set in the jig and aligned so that the hole 12d of the flange 12 overlaps with the metal layer 11 of the ceramic body 5, and then brazed using the joining material 13 at a temperature of about 1000 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, an example of an embodiment of the cleaning device of the present disclosure will be described.

The cleaning device of this embodiment includes the above-mentioned heat exchange units 1, 1A, 1B, 1C, 1D, and 1E. The cleaning device is configured to discharge the fluid heated by the heater 3 that flows through the flow path 10 to the outside through 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 side of the ceramic body 5, then flows into the second space 10b, and is discharged to the outside through 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 a local part of the human body. The cleaning device of this embodiment includes the heat exchange units 1, 1A, 1B, 1C, 1D, and 1E, so that the fluid can be effectively heated.

Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above-mentioned embodiments, and various modifications, improvements, etc. are possible within the scope of the gist of the present disclosure. It goes without saying that all or part of the components of each of the above-mentioned embodiments can be combined appropriately and to the extent that there are no contradictions.

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 5c Recess 5d, 5e End 5f Inner circumferential surface 5g Outer circumferential surface 5h Recess area 6 Heating resistor 6a Straight 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 (11)

a cylindrical ceramic body extending in a longitudinal direction and open at both ends;
a meandering heating resistor that is embedded in the ceramic body, extends from one end of the ceramic body to the other end in a longitudinal direction of the ceramic body, and includes a plurality of linear portions and a plurality of folded portions;
a lead conductor connected to the heating resistor, extending toward the other end of the ceramic body and having a resistance per unit length lower than that of the heating resistor ;
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 via a joining material;
a cylindrical case having one end closed and the other end open, the heater being inserted into the opening of the other end and housing at least a portion of the ceramic body near 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, the first space and the second space forming a flow path for a fluid;
The case has an outlet port 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,
A heat exchange unit, characterized in that the plurality of folded portions of the heating resistor are positioned in portions overlapping with the bonding material. 2. 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 . 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 end of the ceramic body to the other end in a longitudinal direction thereof, the meandering heating resistor including a plurality of linear portions and a plurality of folded portions;
a lead conductor connected to the heating resistor, extending toward the other end of the ceramic body and having a resistance per unit length lower than that of the heating resistor ;
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 via a joining material;
a cylindrical case having one end closed and the other end open, the heater being inserted into the opening of the other end and housing at least a portion of the ceramic body near 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, the first space and the second space forming a flow path for a fluid;
The case has an outlet port 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,
A heat exchange unit, characterized in that a boundary between the heating resistor and the lead conductor is located in a portion overlapping the bonding material. 4. The heat exchange unit according to claim 1, wherein the outlet and the flange are adjacent to each other. The flange is a metal member,
The joining material is a brazing material,
5. A heat exchange unit according to claim 1, wherein 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. The heat exchange unit according to claim 5 , wherein the bonding material has a meniscus portion extending from the metal layer to the flange, the meniscus portion being located on the one end side and the other end side of the ceramic body. 7. The heat exchange unit according to claim 1, wherein the heating resistor extends toward the other end of the ceramic body beyond a portion of the ceramic body facing the outlet port. A heat exchange unit as described in any one of claims 1 to 7, 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 port with respect to the centroid of the ceramic body. the ceramic body has a recess on the outer circumferential surface extending in the longitudinal direction,
A heat exchange unit as described in any one of claims 1 to 8, 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 to the part facing the outlet. 10. The heat exchange unit according to claim 1, wherein the outlet of the case is adjacent to an opening of the case. A cleaning device comprising the heat exchange unit according to any one of claims 1 to 10 , wherein the fluid heated by the heater and flowing through the flow path is discharged to the outside via the outlet.