Fluid heating device

Abstract

To reduce risk of electric leakage caused in a heater conductor.SOLUTION: A heater comprises a planar ceramic laminate having a firs face and a second face, heater conductors arranged between layers of the ceramic laminate, first sensor conductors arranged closer to the first face side of the ceramic laminate than the heater conductors, and second senor conductors arranged closer to the second face side of the ceramic laminate than the heater conductors. The density of the first sensor arrangement and the density of the second sensor arrangement are mutually different.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a heater and a fluid heating device used in a water heater for vehicle heating, a heater for a shower toilet, or the like.

Background Art

[0002] As a heater used for fluid heating such as a water heater for vehicle heating or a heater for a shower toilet, for example, a ceramic heater described in Patent Document 1 can be mentioned.

[0003] The ceramic heater described in Patent Document 1 includes a ceramic layer, a heater wiring provided between the layers of the ceramic layer, and a crack detection wiring. Thereby, when a crack occurs in the ceramic layer, the crack in the ceramic layer can be detected by the disconnection of the crack detection wiring.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in such a ceramic heater, the crack detection wiring was provided only on one side of the heater wiring. Therefore, when water intrusion occurred from the opposite side, it was impossible to detect electric leakage from the heater wiring. As a result, it was difficult to reduce the risk of electric leakage from the heater wiring.

Means for Solving the Problems

[0006] The heater of the present disclosure includes a plate-shaped ceramic laminate having a first surface and a second surface, a heater conductor located between the layers of the ceramic laminate, a first sensor conductor located on the first surface side of the heater conductor in the ceramic laminate, and a second sensor conductor located on the second surface side of the heater conductor in the ceramic laminate, and is characterized in that the density of arrangement of the first sensor conductor and the density of arrangement of the second sensor conductor are different.

[0007] Further, the fluid heating device of the present disclosure includes the heater and a flow path member into which the heater is inserted and which has an inlet and an outlet. The heater has different densities of arrangement of the first sensor conductor and the second sensor conductor, and the flow path member is characterized in that the inlet is located on the first surface side and the outlet is located on the second surface side.

Advantages of the Invention

[0008] According to the heater of the present disclosure, it has a first sensor conductor located on the first surface side of the heater conductor in the ceramic laminate and a second sensor conductor located on the second surface side of the heater conductor in the ceramic laminate. Thus, even if water intrusion occurs from either the first surface side or the second surface side of the heater conductor, a resistance change occurs in the first sensor conductor or the second sensor conductor. By detecting this resistance change, water intrusion can be detected. As a result, the risk of electric leakage from the heater conductor can be reduced.

[0009] Further, according to the heater of the present disclosure, the density of arrangement of the first sensor conductor and the density of arrangement of the second sensor conductor are different. Therefore, for example, while increasing the detectability of water intrusion on the surface side where water intrusion is likely to occur, the thermal stress between the ceramic laminate and the sensor conductor can be reduced on the surface side where water intrusion is less likely to occur. Thereby, while enhancing the durability of the heater, the risk of electric leakage from the heater conductor can be reduced well.

Brief Description of the Drawings

[0010]

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Mode for Carrying Out the Invention

[0011] Hereinafter, the heater 10 will be described with reference to the drawings. The heater 10 according to an example of the present disclosure includes a plate-shaped ceramic laminate 1, a heater conductor 2, a first sensor conductor 3, and a second sensor conductor 4. Hereinafter, an example of the heater 10 shown in FIGS. 1 to 5 will be described.

[0012] The ceramic laminate 10 is a plate-shaped member having an upper surface 11 and a lower surface 12. The ceramic laminate 10 has a material such as aluminum oxide, silicon nitride, or aluminum nitride. The ceramic laminate 10 is composed of a plurality of ceramic layers. An insulating film 5 containing an insulating material such as glass or resin may be provided on the surface of the ceramic laminate 10. The dimensions of the ceramic laminate 10 can be, for example, a length of 20 to 250 mm, a width of 10 to 250 mm, and a thickness of 0.3 to 10 mm.

[0013] The heater conductor 2 is a member that generates heat when energized. The heater conductor 2 is located between the layers of the ceramic laminate 10. The heater conductor 2 is, for example, a linear, string-shaped, or strip-shaped member. The heater conductor 2 may have a plurality of folded portions. The heater conductor 2 may be located so as to be routed over the entire surface among the layers of the ceramic laminate 10. The heater conductor 2 has a conductive material such as tungsten, platinum, gold, silver, copper, nickel, molybdenum, or palladium. The dimensions of the heater conductor 2 can be, for example, a total length of 10 to 6000 mm, a width of 0.2 to 3 mm, and a thickness of 0.01 to 0.5 mm. Further, the heater conductor 2 is connected to the lead terminal 6 on one end side of the heater 10 and may be energized with an external member. By the heat generation of the heater conductor 2, the fluid touching the upper surface 11 and the lower surface 12 of the ceramic laminate 10 can be heated.

[0014] The first sensor conductor 3 and the second sensor conductor 4 are conductors that detect the presence or absence of water immersion due to a change in resistance. The first sensor conductor 3 is provided on the upper surface 11 side of the heater conductor 2 in the ceramic laminate 10. Here, among the ceramic laminate 10, the upper surface 11 The "side" includes the upper surface 11 of the ceramic laminate 10. The second sensor conductor 4 is provided on the lower surface 12 side of the ceramic laminate 10 with respect to the heater conductor 2. Here, the lower surface 12 side of the ceramic laminate 10 with respect to the heater conductor 2 includes the lower surface 12 of the ceramic laminate 10. For example, it is a linear, string-like, or strip-like member. The first sensor conductor 3 and the second sensor conductor 4 may have a plurality of folded portions. The first sensor conductor 3 and the second sensor conductor 4 are made of a conductive material such as tungsten, platinum, gold, silver, copper, nickel, molybdenum, or palladium, for example. The dimensions of the first sensor conductor 3 and the second sensor conductor 4 can be, for example, a total length of 10 to 7000 mm, a width of 0.1 to 3 mm, and a thickness of 0.01 to 0.5 mm. The first sensor conductor 3 and the second sensor conductor 4 may have the same material or may be formed from different materials. Also, the first sensor conductor 3 and the second sensor conductor 4 are connected to the lead terminal 6 at one end side of the heater 10 and may be energized with an external member.

[0015] Figures 2 to 5 are cross-sectional views showing a cross-section perpendicular to the upper surface 11 or the lower surface 12 of the ceramic laminate 10. As shown in FIG. 2, the heater 10 of the present disclosure has a first sensor conductor 3 located on the upper surface 11 side of the ceramic laminate 10 with respect to the heater conductor 2 and a second sensor conductor 4 located on the lower surface 12 side of the ceramic laminate 10 with respect to the heater conductor 2. Thereby, even if water immersion occurs from either the upper surface 11 side or the lower surface 12 side of the heater conductor 2, a resistance change occurs in the first sensor conductor 3 or the second sensor conductor 4, and by detecting this resistance change, water immersion can be detected. As a result, the risk of electric leakage from the heater conductor 2 can be reduced.

[0016] Further, as shown in Fig. 2(a), the first sensor conductor 3 or the second sensor conductor 4 may be provided at a position overlapping in the stacking direction of the ceramic laminate 10. Thereby, the first sensor conductor 3 or the second sensor conductor 4 can be provided on a straight line connecting the heater conductor 2 from the upper surface 11 or the lower surface 12 of the ceramic laminate 10 at the shortest distance. Therefore, the first sensor conductor 3 or the second sensor conductor 4 can be provided at a location where the risk of water immersion is high. As a result, the risk of electric leakage from the heater conductor 2 can be reduced.

[0017] Also, the width of the ceramic laminate 10 and the width of the first sensor conductor 3 or the second sensor conductor 4 may be substantially the same.

[0018] Further, as shown in Fig. 2(b), the first sensor conductor 3 or the second sensor conductor 4 may be provided at a position not overlapping in the stacking direction of the ceramic laminate 10. In other words, the first sensor conductor 3 or the second sensor conductor 4 may be provided between the ceramic laminates 10. Thereby, due to the heat generation of the heater conductor 2, thermal stress is generated between the first sensor conductor 3 or the second sensor conductor 4 and the ceramic laminate 10, and the risk of the first sensor conductor 3 or the second sensor conductor 4 being disconnected can be reduced. As a result, the durability of the heater 10 can be enhanced.

[0019] Also, as shown in Fig. 2(c), the thickness of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the thickness of the heater conductor 2. Further, as shown in Fig. 2(d), the width of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the width of the heater conductor 2. Thereby, since the resistance value per unit length can be increased, a small resistance change due to a fine crack or the like can also be detected. Therefore, the first sensor conductor 3 or the second sensor conductor 4 can be provided. As a result, the risk of electric leakage from the heater conductor 2 can be reduced.

[0020] Also, the width of the ceramic laminate 10 and the width of the first sensor conductor 3 or the second sensor conductor 4 may be substantially the same.

[0021] Further, as shown in Fig. 2(b), the first sensor conductor 3 or the second sensor conductor 4 may be provided at a position that does not overlap in the stacking direction of the ceramic laminate 10. In other words, the first sensor conductor 3 or the second sensor conductor 4 may be provided between the ceramic laminates 10. Thereby, due to the heat generation of the heater conductor 2, thermal stress is generated between the first sensor conductor 3 or the second sensor conductor 4 and the ceramic laminate 10, and the risk of disconnection of the first sensor conductor 3 or the second sensor conductor 4 can be reduced. As a result, the durability of the heater 10 can be enhanced.

[0022] Also, as shown in Fig. 2(c), the thickness of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the thickness of the heater conductor 2. Further, as shown in Fig. 2(d), the width of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the width of the heater conductor 2. Thereby, since the resistance value per unit length can be increased, even a small resistance change due to a fine crack or the like can be detected. Therefore, the first sensor conductor 3 or the second sensor conductor 4 can be made more likely to detect a resistance change. As a result, the risk of leakage current from the heater conductor 2 can be reduced.

[0023] Also, as shown in Fig. 2(d), the first sensor conductor 3 or the second sensor conductor 4 may be arranged at a higher density than the heater conductor 2. Thereby, the possibility that the first sensor conductor 3 or the second sensor conductor 4 can detect water ingress can be further enhanced. As a result, the risk of leakage current from the heater conductor 2 can be reduced.

[0024] Also, as shown in Fig. 3(e), the width of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the width of the heater conductor 2, and the first sensor conductor 3 or the second sensor conductor 4 may be provided at a position overlapping the heater conductor 2.

[0025] Further, as shown in FIG. 3(f), the first sensor conductor 3 or the second sensor conductor 4 is provided at a position overlapping the heater conductor 2, and when viewed in cross section, both ends of the first sensor conductor 3 or the second sensor conductor 4 may be displaced in a direction perpendicular to the stacking direction with respect to both ends of the heater conductor 2. Thereby, when thermal stress is generated at both ends of the heater conductor 2, the first sensor conductor 3, or the second sensor conductor 4, the thermal stress can be dispersed. Thereby, the durability of the heater 10 can be enhanced.

[0026] Further, as shown in FIG. 3(g), the arrangement densities of the first sensor conductor 3 and the second sensor conductor 4 may be different. Also, for example, an inlet is located on the upper surface 11 side and an outlet is located on the lower surface 12 side, and the first sensor conductor 3 may be provided more densely than the second sensor conductor 4. In this case, since the fluid flowing on the inlet side is at a lower temperature than the fluid flowing on the outlet side, thermal stress is likely to occur and water ingress is likely to occur on the upper surface 11 located on the inlet side. In this way, by providing the first sensor conductor 3 densely on the upper surface 11 side where water ingress is likely to occur, water ingress can be detected more easily. In addition, since the second sensor conductor 4 located on the lower surface 12 side where thermal stress is relatively unlikely to occur is provided less densely than the first sensor conductor 3, the thermal stress due to the difference in thermal expansion between the second sensor conductor 4 and the ceramic laminate 10 can be reduced. As a result, while enhancing the durability of the heater 10, the risk of electric leakage from the heater conductor 2 can be reduced.

[0027] Further, as shown in FIG. 4, the first sensor conductor 3 may be provided on the upper surface 11 of the ceramic laminate 10. Similarly, the second sensor conductor 4 may be provided on the lower surface 12 of the ceramic laminate 10. In this case, compared with the case where the first sensor conductor 3 or the second sensor conductor 4 is embedded inside the ceramic laminate 10, the heat capacity of the ceramic laminate 10 can be reduced. Therefore, it is possible to facilitate the transfer of the heat generated by the heater conductor 2 to the fluid. As a result, the heating efficiency of the fluid can be enhanced.

[0028] Also, as shown in FIG. 5, the heater 10 may have an insulating film 5 on the upper surface 11 of the ceramic laminate 10, and the first sensor conductor 3 may be provided between the upper surface 11 of the ceramic laminate 10 and the insulating film 5. Thereby, when a crack occurs between the heater conductor 2 and the ceramic laminate 10, the progress of the crack can be stopped at the interface between the ceramic laminate 10 and the insulating film 5. As a result, the durability of the heater 10 can be enhanced.

[0029] Hereinafter, the heater 10 of other examples shown in FIGS. 6 to 16 will be described. The heater 10 includes a cylindrical ceramic laminate 10, a heater conductor 2, a first sensor conductor 3, and a second sensor conductor 4.

[0030] The ceramic laminate 10 is a cylindrical member having an inner peripheral surface 13 and an outer peripheral surface 14. The ceramic laminate 10 has a material such as, for example, aluminum oxide, silicon nitride, or aluminum nitride. The ceramic laminate 10 is composed of a plurality of ceramic layers. An insulating film 5 containing an insulating material such as glass or resin may be provided on the surface of the ceramic laminate 10. The dimensions of the ceramic laminate 10 can be, for example, a length of 20 to 250 mm, an inner diameter of 1 to 78 mm, an outer diameter of 1.5 to 80 mm, and a thickness of 0.5 to 5 mm.

[0031] Note that a groove extending in the longitudinal direction may be provided on the outer peripheral surface 14 of the ceramic laminate 10. Thereby, the thermal stress of the outer peripheral surface 14 of the ceramic laminate 10 can be reduced.

[0032] The heater conductor 2 is a member that generates heat when energized. The heater conductor 2 is located between the layers of the ceramic laminate 10. The heater conductor 2 is, for example, a linear, string-like, or strip-like member. The heater conductor 2 may have a plurality of folded portions. The heater conductor 2 may be located so as to be routed throughout the entire area between the layers of the ceramic laminate 10. The heater conductor 2 has, for example, a conductive material such as tungsten, platinum, gold, silver, copper, nickel, molybdenum, or palladium. The dimensions of the heater conductor 2 can be, for example, a total length of 10 to 4000 mm, a width of 0.2 to 3 mm, and a thickness of 0.01 to 0.5 mm. By the heat generation of the heater conductor 2, the fluid that touches the inner peripheral surface 13 and the outer peripheral surface 14 of the ceramic laminate 10 can be heated.

[0033] The first sensor conductor 3 and the second sensor conductor 4 are conductors that detect the presence or absence of water immersion due to a change in resistance. The first sensor conductor 3 is provided on the inner peripheral surface 13 side of the heater conductor 2 in the ceramic laminate 10. Here, the inner peripheral surface 13 side of the heater conductor 2 in the ceramic laminate 10 includes the inner peripheral surface 13 of the ceramic laminate 10. The second sensor conductor 4 is provided on the outer peripheral surface 14 side of the heater conductor 2 in the ceramic laminate 10. Here, the outer peripheral surface 14 side of the heater conductor 2 in the ceramic laminate 10 includes the outer peripheral surface 14 of the ceramic laminate 10. They are, for example, linear, string-like, or strip-like members. The first sensor conductor 3 and the second sensor conductor 4 may have a plurality of folded portions. The first sensor conductor 3 and the second sensor conductor 4 have, for example, a conductive material such as tungsten, platinum, gold, silver, copper, nickel, molybdenum, or palladium. The dimensions of the first sensor conductor 3 and the second sensor conductor 4 can be, for example, a total length of 10 to 5000 mm, a width of 0.1 to 3 mm, and a thickness of 0.01 to 0.5 mm. The first sensor conductor 3 and the second sensor conductor 4 may have the same material or may be formed from different materials. Also, the first sensor conductor 3 and the second sensor conductor 4 are connected to the lead terminal 6 on one end side of the heater 10, and thereby may be energized with an external member.

[0034] As shown in FIG. 7, according to the heater 10 of another example of the present disclosure, among the ceramic laminates 10, a first sensor conductor 3 located on the inner peripheral surface 13 side of the heater conductor 2 and a second sensor conductor 4 located on the outer peripheral surface 14 side of the heater conductor 2 in the ceramic laminate 10 are provided. Thereby, even if water immersion occurs from either the inner peripheral surface 13 side or the outer peripheral surface 14 side of the heater conductor 2, a resistance change occurs in the first sensor conductor 3 or the second sensor conductor 4. Therefore, by detecting this resistance change, water immersion can be detected. As a result, the risk of electric leakage from the heater conductor 2 can be reduced.

[0035] Further, as shown in FIG. 7, the first sensor conductor 3 or the second sensor conductor 4 may be provided at a position overlapping in the radial direction of the ceramic laminate 10. Thereby, the first sensor conductor 3 or the second sensor conductor 4 can be provided on a straight line connecting the heater conductor 2 from the inner peripheral surface 13 or the outer peripheral surface 14 of the ceramic laminate 10 at the shortest distance. Therefore, the first sensor conductor 3 or the second sensor conductor 4 can be provided at a location where the risk of water immersion is high. As a result, the risk of electric leakage from the heater conductor 2 can be reduced.

[0036] Also, the width of the ceramic laminate 10 and the width of the first sensor conductor 3 or the second sensor conductor 4 may be substantially the same.

[0037] Further, as shown in FIG. 8, the first sensor conductor 3 or the second sensor conductor 4 may be provided at a position not overlapping in the radial direction of the ceramic laminate 10. In other words, the first sensor conductor 3 or the second sensor conductor 4 may be provided between the ceramic laminates 10. Thereby, due to the heat generation of the heater conductor 2, a thermal stress is generated between the first sensor conductor 3 or the second sensor conductor 4 and the ceramic laminate 10, and the risk that the first sensor conductor 3 or the second sensor conductor 4 is disconnected can be reduced. As a result, the durability of the heater 10 can be enhanced.

[0038] Also, as shown in FIG. 9, the thickness of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the thickness of the heater conductor 2. Further, as shown in FIG. 10, the width of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the width of the heater conductor 2. Thereby, since the resistance value per unit length can be increased, even a small resistance change due to a fine crack or the like can be detected. Therefore, the first sensor conductor 3 or the second sensor conductor 4 can be provided. As a result, the risk of leakage current from the heater conductor 2 can be reduced.

[0039] Also, as shown in FIG. 10, the first sensor conductor 3 or the second sensor conductor 4 may be arranged at a higher density than the heater conductor 2. Thereby, the possibility that the first sensor conductor 3 or the second sensor conductor 4 can detect water ingress can be further increased. As a result, the risk of leakage current from the heater conductor 2 can be reduced.

[0040] Also, as shown in FIG. 11, the width of the first sensor conductor 3 or the second sensor conductor 4 may be smaller than the width of the heater conductor 2, and the first sensor conductor 3 or the second sensor conductor 4 may be provided at a position overlapping the heater conductor 2.

[0041] Also, as shown in FIG. 12, the first sensor conductor 3 or the second sensor conductor 4 is provided at a position overlapping the heater conductor 2, and when viewed in cross section, both ends of the first sensor conductor 3 or the second sensor conductor 4 may be displaced in a direction perpendicular to the lamination direction with respect to both ends of the heater conductor 2. Thereby, when thermal stress is generated at both ends of the heater conductor 2, the first sensor conductor 3, or the second sensor conductor 4, the thermal stress can be dispersed. Thereby, the durability of the heater 10 can be enhanced.

[0042] Also, as shown in FIG. 13, the arrangement densities of the first sensor conductor 3 and the second sensor conductor 4 are different That is, the density of the second sensor conductor 4 located on the outer peripheral surface 14 side may be higher than that of the first sensor conductor 3 located on the inner peripheral surface 13 side. Also, as shown in FIG. 14, the density of the first sensor conductor 3 located on the inner peripheral surface 13 side may be higher than that of the second sensor conductor 4 located on the outer peripheral surface 14 side. For example, when an inlet is provided on the inner peripheral side of the ceramic laminate 10 and an outlet is provided on the outer peripheral side of the ceramic laminate 10, the density of the first sensor conductor 3 located on the inner peripheral surface 13 side may be higher than that of the second sensor conductor 4 located on the outer peripheral surface 14 side. Since the fluid flowing on the inlet side flows at a lower temperature than the fluid flowing on the outlet side, thermal stress is likely to occur and water ingress is likely to occur on the inner peripheral surface 13 located on the inlet side. Thus, by densely providing the first sensor conductor 3 located on the inner peripheral surface 13 side where water ingress is likely to occur, water ingress can be detected more accurately. In addition, since the second sensor conductor 4 located on the outer peripheral surface 14 side where thermal stress is relatively unlikely to occur is provided less densely than the first sensor conductor 3, thermal stress due to the difference in thermal expansion between the ceramic laminate 10 can be reduced. As a result, while enhancing the durability of the heater 10, the risk of electric leakage from the heater conductor 2 can be reduced.

[0043] Also, as shown in FIG. 15, the second sensor conductor 4 may be provided on the outer peripheral surface 14 of the ceramic laminate 10. Similarly, the first sensor conductor 3 may be provided on the inner peripheral surface 13 of the ceramic laminate 10. In this case, compared with the case where the first sensor conductor 3 or the second sensor conductor 4 is embedded inside the ceramic laminate 10, the heat capacity of the ceramic laminate 10 can be reduced. Therefore, the heat generated by the heater conductor 2 can be easily transferred to the fluid. As a result, the heating efficiency of the fluid can be enhanced.

[0044] Also, as shown in FIG. 16, the heater 10 may have an insulating film 5 on the outer peripheral surface 14 of the ceramic laminate 10, and the second sensor conductor 4 may be provided between the upper surface 11 of the ceramic laminate 10 and the insulating film 5. Thereby, when a crack occurs between the heater conductor 2 and the ceramic laminate 10, the progress of the crack can be stopped at the interface between the ceramic laminate 10 and the insulating film 5. As a result, the durability of the heater 10 can be enhanced.

[0045] Hereinafter, a usage example of the heater 10 of the present disclosure will be described. As shown in FIG. 17, for example, the heater 10 may be provided with a flange 7 on one end side, and the other end side may be inserted into the flow path member 8. The flange 7 and the flow path member 8 may be members such as ceramics or metal, for example. The flow path member 8 may be, for example, an annular member, and a flow path may be formed by the inner peripheral surface 13 of the flow path member 8 and the outer surface of the heater 10. Further, the inlet or the outlet may be provided on the flange 7. The flow path member 8 may have, for example, an inlet on the upper surface 11 side of the ceramic laminate 10 and an outlet on the lower surface 12 side of the ceramic laminate 10.

[0046] Also, as shown in FIG. 18, when the heater 10 is cylindrical, the inner peripheral side of the heater 10 can be used as a flow path. Further, one end side of the heater 10 may be an inlet or an outlet. Thereby, since the flow path provided in the flow path member 8 or the flange 7 can be reduced, the liquid tightness can be enhanced.

Description of Reference Numerals

[0047] 1: Ceramic laminate 11: Upper surface 12: Lower surface 13: Inner peripheral surface 14: Outer peripheral surface 2: Heater conductor 3: First sensor conductor 4: Second sensor conductor 5: Insulating film 6: Lead terminal 7: Flange 8: Flow path member 10: Heater

Claims

[Claim 1] A heater, a flow path member into which the heater is inserted and which has an inlet and an outlet; The heater is a ceramic laminate having a first surface and a second surface opposite to the first surface; a heater conductor located between layers of the ceramic laminate; a first sensor conductor located closer to the first surface than the heater conductor; a second sensor conductor located closer to the second surface than the heater conductor; a density of the first sensor conductors located on the first surface side is higher than a density of the second sensor conductors located on the second surface side; The flow path member has the inlet located on the first surface side and the outlet located on the second surface side.

Images