Heater and heater unit

Abstract

To provide a heater that can heat a fluid to be heated evenly and efficiently throughout the entire flow path in response to various fluid forms, and a heater unit including the heater.SOLUTION: A heater 3 is for heating a fluid to be heated that flows through a flow path 25 formed on an upper surface 24 of a base 21, and includes a substrate 31 arranged to cover the upper surface of the base, a heating element 32 arranged on one side of the substrate, and a power supply line 35 arranged on the one side of the substrate along the flow path. The heating element includes a plurality of heat generating cells 33 each of which receives power, and the plurality of heat generating cells are connected in parallel to the power supply line and are arranged side by side along the flow path from an inlet 26a to an outlet 26b provided in the base.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a heater and a heater unit, and more particularly, to a heater and a heater unit including the same.

Background Art

[0002] As a device for heating a fluid such as water, a fluid heater that heats a fluid flowing in a meandering flow path in a planar shape is known (see, for example, Patent Documents 1 and 2). Patent Document 1 describes a fluid heater including a meandering flow path in a planar shape and a flat plate covering the flow path, the flat plate having a ceramic heater composed of a resistive heating element on its surface. Further, Patent Document 2 describes a fluid heater provided with a single meandering heating resistor so as to be in contact with a meandering flow path in a planar spiral shape.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the fluid heaters disclosed in Patent Documents 1 and 2, since the entire flow path is heated by a heating resistor extending along the flow path, the entire flow path is not uniformly heated corresponding to various fluid forms (e.g., fluid velocity, fluid temperature, etc.), and a part thereof tends to become high temperature. As a result, the heater in the high temperature part is likely to be damaged, or when the fluid is a liquid in the high temperature part and the liquid boils, the heat transfer from the heater to the liquid suddenly becomes small and the heating efficiency of the entire liquid deteriorates, or the deterioration of the fluid progresses due to partial high heat. In particular, when a resistance heating element with a high temperature coefficient of resistance is used as the heater, the temperature further rises due to its own heat generation, and the heat generation amount of other parts relatively decreases. Therefore, it is necessary to perform power control according to the high heat generation part, and there is a problem that the heating performance of the entire fluid heater is impaired. In addition, when the substrate of the heater is made of steel, in the prior art, if the thickness of the substrate is thin, warping of the substrate occurs with the heater side convex, making it difficult to closely adhere and bond to the housing and causing fluid leakage. Therefore, for example, a substrate thickness of 3 mm or more is required, and the heat capacity is large, taking a long time to heat.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a heater capable of uniformly and efficiently heating a fluid to be heated throughout a flow path corresponding to various fluid forms, and a heater unit including the same.

Means for Solving the Problems

[0006] The present invention is as follows. 1. A heater for heating a fluid to be heated flowing through a flow path formed on the upper surface of a base, comprising a substrate disposed so as to cover the upper surface of the base, a heating element disposed on one surface side of the substrate, and a power supply line disposed on one surface side of the substrate along the flow path, the heating element having a plurality of heating cells each receiving power supply, the plurality of heating cells being connected in parallel to the power supply line, The plurality of the heating cells are arranged side by side along the flow path from an inlet provided in the base toward an outlet, and the heater is characterized by this arrangement. 2. The heater according to 1. above, wherein the resistance heating wire constituting the heating element is formed of a material having a high resistance temperature coefficient and / or a PTC material. 3. The heater according to 1. or 2. above, wherein a reinforcing layer is arranged along the flow path on the surface side of the substrate facing the flow path. 4. The heater according to 3. above, wherein an exposed portion communicating the surface side of the substrate facing the flow path with the flow path is formed in the reinforcing layer. 5. The heater according to 4. above, wherein a heat sink protruding into the flow path through the exposed portion is arranged on the surface side of the substrate facing the flow path. 6. The heater according to 4. above, wherein an embedded member formed of a material having a higher thermal conductivity than the material constituting the substrate is embedded in the exposed portion. 7. The heater according to 3. above, wherein the reinforcing layer is an insulating layer. 8. The heater according to 3. above, wherein the reinforcing layer is a heat dissipation layer formed of a material having a higher thermal conductivity than the material constituting the substrate. 9. The heater according to 1. or 2. above, wherein the substrate is formed of a clad material or a bimetal. 10. The heater according to 1. or 2. above, further comprising an insulating layer arranged on one surface side of the substrate to cover the heating element. 11. The heater according to 1. or 2. above, wherein the heating element is formed by printing a resistance heating wire on the substrate. 12. The heater according to 1. or 2. above, wherein the heating cell is formed in a zigzag curved shape including a parallel portion formed in a direction perpendicular to the flow direction of the flow path and a bent portion connecting adjacent parallel portions. 13. The heater according to 1. or 2. above, wherein the heating cell is formed in a zigzag curved shape including a parallel portion formed in a direction parallel to the flow direction of the flow path and a bent portion connecting adjacent parallel portions. 14. A heater unit comprising a base and a heater for heating a fluid to be heated flowing through a flow path formed on the upper surface of the base. The heater is the heater according to any one of the above items 1 to 13, and the heater unit is characterized in that.

Effect of the Invention

[0007] According to the present invention, it is possible to heat the fluid to be heated evenly and efficiently throughout the flow path in response to various fluid forms.

Brief Description of the Drawings

[0008] The present invention will be further described in the following detailed description with reference to a non-limiting example of a typical embodiment according to the present invention and referring to the plurality of drawings mentioned, where like reference numerals indicate like parts throughout several views of the drawings.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Figure 30

Figure 31

Figure 32

Figure 33

Embodiments for Carrying Out the Invention

[0009] The matters shown here are exemplary and for exemplarily explaining the embodiments of the present invention, and are described for the purpose of providing an explanation that can most effectively and without difficulty understand the principle and conceptual features of the present invention. In this regard, it is not intended to show the structural details of the present invention to a greater extent than necessary for a fundamental understanding of the present invention, and it is to clarify for those skilled in the art how several forms of the present invention are actually embodied by the description in combination with the drawings.

[0010] (Heater) The heater according to this embodiment is, for example, as shown in FIGS. 1 to 4, a heater 3 for heating a fluid to be heated flowing through a flow path 25 formed on the upper surface (flow path forming surface) 24 of a base 21, and includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one surface side of the substrate 31, and a power supply line 35 disposed on one surface side of the substrate 31 along the flow path 25. And, for example, as shown in FIG. 5, the heating element 32 has a plurality of heating cells 33 that are individually powered, the plurality of heating cells 33 are connected in parallel to the power supply line 35, and the plurality of heating cells 33 are arranged side by side along the flow path 25 from an inlet 26a to an outlet 26b provided in the base 21. Note that the heating element 32 may be disposed on the surface side of the substrate 31 facing the flow path 25, or may be disposed on the surface side of the substrate 31 opposite to the surface facing the flow path 25.

[0011] According to the above configuration, by adjusting the heat generation amount of each heating cell 33, it is possible to adjust the heat generation amount according to the position of the flow path 25. In addition, the function of self-temperature compensation works for each heating cell 33, and it is possible to heat efficiently and in a well-balanced manner with respect to various fluid velocities and fluid temperatures.

[0012] (Base) The base 21 usually has a fluid inlet 26a and an outlet 26b that are continuous with the flow path 25. Further, the material of the base 21 is not particularly limited, and for example, a metal base, a synthetic resin base, or a ceramic base can be used. Furthermore, the shape of the base 21 is not particularly limited, and for example, a flat rectangular shape, a polygonal shape, a circular shape, an elliptical shape, or a base with an irregular shape can be used.

[0013] The flow path 25 is usually open on the upper surface 24 of the base 21. Also, the shape of the flow path 25 is not particularly limited, and one or a combination of two or more types such as linear, curved, and bent shapes can be used. From the viewpoint of heat exchange efficiency, the flow path 25 is preferably a meandering flow path in which a linear flow path flowing in a linear direction and a curved flow path for reversing the flow direction are alternately arranged. Furthermore, the type of the fluid to be heated is not particularly limited, and for example, liquids such as water and oil, gases, gel-like substances, etc. can be used.

[0014] (Reinforcing layer) From the viewpoints of thinning (i.e., weight reduction) of the substrate 31 and warpage suppression, it is preferable that reinforcing layers 41 and 44 are arranged along the flow path on the surface side of the substrate 31 facing the flow path 25 (see, for example, FIGS. 7, 10, 14, 17, and 19).

[0015] An insulating layer 41 can be used as the reinforcing layer. The material of the insulating layer 41 is not particularly limited, but for example, glass, ceramics, glass-ceramics, etc. are preferable. Among these, when a metal (such as stainless steel) is used as the material constituting the substrate 31, the material of the insulating layer 41 is preferably glass, more preferably crystallized glass and semi-crystallized glass, from the viewpoint of its thermal expansion balance. Specifically, SiO2 - Al2O3 - MO - based glass is preferable. Here, MO is an oxide of an alkaline earth metal (MgO, CaO, BaO, SrO, etc.). The thickness of the insulating layer is not particularly limited (for example, about 30 to 200 μm).

[0016] As the reinforcing layer, a heat equalizing layer 44 can be used. The heat equalizing layer 44 serves to equalize the heat fluctuations formed in the heating element 32. That is, when there is a drop in the heating temperature, it can raise the temperature to the same as that of its surroundings, and when there is a protrusion in the heating temperature, it can lower the temperature to the same as that of its surroundings to equalize the heat fluctuations. Particularly, when the heating element 32 is formed using a resistive heating wiring having a predetermined pattern shape, it is suitable for equalizing the heat fluctuations caused by this pattern shape. That is, due to having a pattern shape, a part where the resistive heating wiring exists and a part where it does not exist are formed, and a heat fluctuation is formed in which the temperature of the part where the resistive heating wiring exists is higher than that of the part where it does not exist. By passing such heat fluctuations through the heat equalizing layer 44, they can be equalized and the temperature difference can be reduced. From such a viewpoint, providing the heat equalizing layer 44 is effective in a heater including a plurality of heating cells 33 electrically connected in parallel as the heating element 32.

[0017] The heat equalizing layer 44 is formed of a material having a higher thermal conductivity than the material constituting the substrate 31. As the material of the heat equalizing layer 44, for example, when the substrate 31 is made of stainless steel with a low thermal conductivity of 50 W / mK or less, it is preferable to form the heat sink 43 with a material having a thermal conductivity of 100 W / mK or more. Specifically, silver, copper, gold, aluminum, tungsten, nickel, etc., or an alloy containing at least one of these metals can be used as the thermally conductive metal. These thermally conductive metals may be used alone or in combination of two or more. Among these, silver, copper, aluminum, and an alloy containing at least one of these are preferable. Also, for example, when the substrate 31 is made of ceramics such as alumina with a low thermal conductivity of 50 W / mK or less, it is also preferable to form the heat sink 43 with a material having a thermal conductivity of 100 W / mK or more. Specifically, in addition to using thermally conductive ceramics such as aluminum nitride, the above-mentioned various thermally conductive metals can be used.

[0018] The soaking layer 44 can be formed in any way. Specifically, the soaking layer can be provided as a plating layer (electroless plating layer, electroplating layer, composite plating layer thereof, etc.). Also, after printing a paste containing a heat-conductive material and then baking the printed coating film, the soaking layer can be formed. For example, a printing paste containing metal particles (metal powder) as the heat-conductive material can be used. In this case, the printing paste can contain, in addition to the metal particles, a vehicle for pasting and glass components or ceramic components as coexisting components.

[0019] From the perspective of heat exchange efficiency, it is preferable that the reinforcing layers 41 and 44 are formed with exposed portions 42 that communicate the surface side facing the flow path 25 of the substrate 31 and the flow path 25 (see FIG. 10 for example). As the exposed portion 42, for example, (1) a form formed in a long shape along the flow path 25 (see FIG. 9 for example), (2) a form in which a plurality are formed along the flow path 25 (see FIG. 11 for example), etc. can be adopted. These exposed portions 42 can be used alone or in combination of two or more.

[0020] In the form of (1) above, an exposed portion 42 formed in a meandering shape corresponding to the meandering flow path 25 can be used. Also, in the form of (2) above, exposed portions 42 such as a planar V shape, U shape, W shape, L shape, etc., and exposed portions 42 in a planar dot shape (for example, a planar circle, polygon, etc.) can be used. These exposed portions 42 can be used alone or in combination of two or more. Also, the exposed portions 42 in a planar dot shape can be arranged in a plurality along the axial direction and the lateral width direction of the flow path 25 (for example, arranged in a plurality in a staggered pattern).

[0021] (Heat sink) From the perspective of heat exchange efficiency, it is preferable that a heat sink 43 protruding into the flow path 25 is arranged on the surface side of the substrate 31 facing the flow path 25 via the exposed portion 42 (see FIG. 14 for example).

[0022] The heat sink 43 can have, for example, a bonding plate 43a bonded (e.g., adhered, welded, fitted, etc.) to the surface side facing the flow path 25 of the substrate 31, and a heat dissipation plate 43b protruding into the flow path 25 from one surface of the bonding plate 43a. As the heat dissipation plate 43b, for example, (1) a form formed in a long shape along the flow path 25 (e.g., refer to FIG. 13), (2) a form in which a plurality are formed at predetermined intervals along the flow path 25 (e.g., refer to FIGS. 15(a) and (b)), etc. can be adopted. These forms (1) and (2) may be used alone or in combination of two or more.

[0023] In the form of (1) above, the heat sink 43 may include only one heat dissipation plate 43b (e.g., refer to FIG. 13), or may include a plurality of heat dissipation plates 43b arranged opposite to each other (i.e., arranged side by side in the lateral width direction of the flow path 25) (e.g., refer to FIG. 15(c)). Further, in the form of (2) above, the heat sink 43 may include a heat dissipation plate 43b whose one side is substantially aligned or parallel to the axial direction of the flow path 25 (e.g., refer to FIG. 15(a)), or may include a heat dissipation plate 43b whose one side is inclined with respect to the axial direction of the flow path 25 (e.g., refer to FIG. 15(b)).

[0024] The material of the heat sink 43 is not particularly limited, but from the viewpoint of heat exchange efficiency, it is preferably formed of a material having a higher thermal conductivity than the material constituting the substrate 31. For example, when the substrate 31 is made of stainless steel with a low thermal conductivity of 50 W / mK or less, it is preferable to form the heat sink 43 of a material having a thermal conductivity of 100 W / mK or more. Specifically, silver, copper, gold, aluminum, tungsten, nickel, etc., or an alloy containing at least one of these metals can be used as the thermally conductive metal. These thermally conductive metals may be used alone or in combination of two or more. Among these, silver, copper, aluminum, and an alloy containing at least one of these are preferable. Further, for example, even when the substrate 31 is made of ceramics such as alumina with a low thermal conductivity of 50 W / mK or less, it is preferable to form the heat sink 43 of a material having a thermal conductivity of 100 W / mK or more. Specifically, thermally conductive ceramics such as aluminum nitride can be used, and in addition, the above various thermally conductive metals can be used.

[0025] In addition, in the heater 3 not provided with the reinforcing layers 41 and 44 (see, for example, FIG. 3), the heat sink 43 can be disposed on the surface side facing the flow path 25 of the substrate 31 in order to improve the heat exchange efficiency.

[0026] (Embedded member) From the viewpoint of heat exchange efficiency, it is preferable that an embedded member 45 formed of a material having a higher thermal conductivity than the material constituting the substrate 31 is embedded in the exposed portion 42 (see, for example, FIG. 19). As the material of the embedded member 45, for example, the same material as that of the above heat dissipation layer 44 can be used.

[0027] (Other heater) As another heater, for example, as shown in FIGS. 20 and 21, the heating element 32 is disposed on the surface side of the substrate 31 facing the flow path 25. On the surface side of the substrate 31 facing the flow path 25, a power supply terminal 36 electrically connected to the heating element 32 is disposed. On the surface side of the substrate 31 facing the flow path 25, a sealing isothermal layer 46 is disposed so as to seal the flow path 25. The sealing isothermal layer 46 can adopt a form formed of a material having a higher thermal conductivity than the material constituting the substrate 31. The material of the sealing isothermal layer 46 is not particularly limited, but the same material as the above heat sink 43 can be used.

[0028] In the above configuration, from the viewpoint of heat exchange efficiency, it is preferable that a thermally conductive grease layer or a thermally conductive adhesive layer 47 is disposed between the substrate 31 (specifically, the insulating layer 37) and the sealing isothermal layer 46. The type of the thermally conductive grease or adhesive is not particularly limited, but a mixture of a base material such as modified silicone and particles (fillers) of a metal or metal oxide can be used. As the particles, silver, copper, gold, aluminum, tungsten, nickel, etc., or an alloy containing at least one of these metals can be used as the thermally conductive metal. These thermally conductive metals may be used alone or in combination of two or more. Among these, silver, copper, aluminum, and an alloy containing at least one of these are preferable. Further, as the particles, alumina, magnesium oxide, aluminum nitride, etc. can also be used. These may be used alone or in combination of two or more.

[0029] (Substrate) The substrate (31) is a substrate on which a plurality of heating cells 33 are disposed on one surface side. The surface shape of the substrate 31 can be, for example, rectangular in accordance with the flow path forming surface 24, but is not limited thereto, and any shape such as square, L-shaped, arc-shaped, and fan-shaped can be selected in accordance with the shape of the flow path forming surface 24 of the base 21. Further, the thickness of the substrate 31 may be determined according to its material, planar dimensions, required strength, etc.

[0030] The material constituting the substrate 31 is not limited, and for example, metals, ceramics, and composite materials thereof can be used. Examples of the metal constituting the substrate 31 include steel, and among them, stainless steel can be preferably used. The type of stainless steel is not particularly limited, and ferritic stainless steel and / or austenitic stainless steel are preferable. Among these stainless steels, varieties particularly excellent in heat resistance and / or oxidation resistance are preferable. For example, SUS430, SUS436, SUS444, SUS316L, etc. can be mentioned. These may be used alone or in combination of two or more. In addition, as the metal constituting the substrate, aluminum, magnesium, copper, and alloys of these metals can be used. These may be used alone or in combination of two or more. Among them, since aluminum, magnesium, and alloys thereof (such as aluminum alloy, magnesium alloy, and Al-Mg alloy) have a small specific gravity, the weight of this heater can be reduced by adopting these. Also, since copper and its alloys are excellent in thermal conductivity, the heat uniformity of this heater can be improved by adopting these. Further, from the viewpoint of heat exchange efficiency, the substrate 31 is preferably formed of a clad material or a bimetal. The type of the clad material or the bimetal is not particularly limited. For example, it can have a first metal plate formed of steel and a second metal plate having a higher thermal conductivity than the first metal plate. As the first metal plate, stainless steel can be preferably used. On the other hand, as the second metal plate, for example, silver, copper, gold, aluminum, tungsten, nickel, etc., or an alloy containing at least one of these metals can be used. Further, as the clad material or the bimetal, for example, a form in which the first metal plate is joined only to one surface of the second metal plate (for example, SUS-Cu, etc.), a form in which the first metal plate is joined to both surfaces of the second metal plate (for example, SUS-Cu-SUS, etc.), a form in which the second metal plate is joined to both surfaces of the first metal plate (for example, Cu-SUS-Cu, etc.), etc. can be used. Furthermore, those having three or more types of metal plates can also be used.

[0031] In addition, when the substrate is made of ceramics, the material of the substrate may be any material that can achieve electrical insulation from the wiring (resistance heating wire, power supply wiring, power supply terminal, etc.) provided thereon. Preferred substrate materials include, for example, aluminum oxide, aluminum nitride, zirconia, silica, mullite, spinel, cordierite, silicon nitride, etc. These may be used alone or in combination of two or more. Among these, aluminum oxide and aluminum nitride are more preferred. In addition, a composite material of metal and ceramics can also be used as the substrate. Preferred composite materials include, for example, SiC / C, SiC / Al, etc. These may be used alone or in combination of two or more.

[0032] (Heating element) The heating element (32) is composed of a resistance heating wire formed on one side of the substrate 31. The heating element (32) is composed of a power supply wire (35) arranged along the flow path and a plurality of heating cells (33) respectively connected to the power supply wire (35). Here, when the resistance heating wire is printed and formed on the substrate 31, a plurality of heating cells 33 can be formed at one time without increasing the man-hours during manufacturing. In addition, heating cells with different shapes and characteristics can be formed without misplacement.

[0033] The heating cell (33) includes one or more heating elements (34) connected to a pair of power supply wires (35). The configuration of the heating cell 33 may be such that a plurality are formed along the flow path. For example, as shown in FIG. 5, the heating cell 33 may be a strip-shaped single heating element 34, and both ends of the heating element 34 may be connected to the respective power supply wires 35. In addition, as shown in FIG. 22, a heating cell 33 in which a plurality of strip-shaped heating elements 34 are connected to a pair of power supply wires 35 can be cited. These heating elements 34 can be arranged such that the direction orthogonal to the flow direction of the flow path is long as shown in FIGS. 5 and 22. Note that FIG. 5 shows the heater 3 in which the heating cell 33 consists of one heating element. Further, FIG. 22 shows the heater 3 in which the heating cells 33 are connected in series.

[0034] Furthermore, as shown in FIGS. 23 to 27, the heating cell can include a heating element 34 having a parallel portion 38 formed in a direction orthogonal or parallel to the flow direction of the flow path 25 and a bent portion 39 connecting adjacent parallel portions 38. At this time, both ends of the heating element 34 are connected to the respective power supply lines 35. Here, when the heating cell 33 is configured in a zigzag curved shape, the fluid can repeatedly come into contact with the heating cell 33, and it can contribute significantly to heating the fluid by the entire heater unit. This zigzag curved shape can exemplify a configuration including a parallel portion 38 consisting of a straight line formed in a direction orthogonal to the flow direction of the flow path, as shown in FIGS. 23 to 25, and a bent portion 39 consisting of a straight line or / and a curve connecting adjacent parallel portions 38. Also, as shown in FIGS. 26 to 27, a configuration including a parallel portion 38 consisting of a straight line or a curve parallel to the flow direction of the flow path and a bent portion 39 consisting of a straight line or / and a curve connecting adjacent linear portions can be exemplified. Note that FIG. 23 shows the heater 3 in which the heating cell 33 is zigzag folded. FIG. 24 shows the heater 3 in which the heating cell 33 is zigzag folded, and the line thickness of a part of the heating element is thickened, and in order to improve efficiency, a part of the heating cell 33 is replaced with a conductive material such as silver to adjust the resistance value of each heating cell 33. Further, FIG. 25 shows the heater 3 in which two zigzag folded and parallel heating cells 33 are sequentially arranged along the flow path 25. Also, FIGS. 26 and 27 show the heater 3 in which three parallel heating cells 33 having parallel portions arranged in the flow path direction, zigzag folded, and with the line thickness of a part of the heating element thickened are sequentially arranged along the flow path 25.

[0035] Particularly when the heating element 34 is formed by printing, the parallel portion 38 of the heating element 34 can be arranged in a direction perpendicular to the direction in which the fluid flows in the flow path. When the heating element 34 is formed by printing, the curved portion tends to be shallower than the straight portion. For this reason, it is preferable that the bent portion 39 where the printing thickness is likely to be thin is located at a position where it does not cause a thermal shock due to temperature change. Therefore, as shown in Fig. 28(b), when the parallel portion 381 at the tip of the flow path of the heating cell 33 is in a direction perpendicular to the direction in which the fluid flows in the flow path, the bent portion 39 is arranged on the end side of the flow path on the substrate 31, so that it is less likely to come into contact with the fluid. As a result, the thermal shock of the heating element 34 can be alleviated compared to the case where the bent portion 39 is at the tip of the flow path as shown in Fig. 28(a), and damage to the heating element 34 due to thermal shock can be suppressed.

[0036] As exemplified in Figs. 5, 22 to 24, the heating element 32 is not limited to a single row in which the heating cells 33 are arranged in sequence with respect to the flow path, and a heating element 32 having two or more rows may be configured. For example, as exemplified in Fig. 25, a heater 3 including two rows of heating elements 32 composed of a row in which the heating cells 331 are arranged in sequence and a row in which the heating cells 332 are arranged in sequence can be cited. Further, for example, as exemplified in Figs. 26 and 27, a heater 3 including three rows of heating elements 32 composed of a row in which the heating cells 331 are arranged in sequence, a row in which the heating cells 332 are arranged in sequence, and a row in which the heating cells 333 are arranged in sequence can be cited. The heater 3 including the heating element 32 composed of a plurality of rows of heating cells 331 to 333 as described above can perform heat generation adjustment in accordance with the temperature difference due to the difference in position between the vicinity of the center and the periphery of the flow path.

[0037] The calorific value of each heating cell 33 is appropriately set according to the target heater unit. For example, the calorific value per unit area of the heating cell may be common to all the heating cells, or may be changed for each heating cell. When changing for each heating cell, the calorific value may be gradually increased or decreased from the inlet to the outlet of the flow path, or the calorific value may be increased or decreased near the center of the flow path. The method of changing the calorific value of the heating cell can be appropriately selected. For example, the number of heating elements 34 per unit area can be changed, or the wire length, wire width, and / or wire thickness of the heating element 34 can be changed. In addition, when the heating elements 34 of the heating cell are connected in parallel, it is preferable that the electrical characteristics such as the resistance value and the resistance heating characteristics of each heating cell connected in parallel are substantially the same. This is because by making them the same, it is possible to prevent the current from flowing more largely through the low-resistance heating element 34 than through other heating elements 34 and thus prevent it from being easily damaged.

[0038] When a high-TCR material (a material with a high temperature coefficient of resistance) is selected as the wiring material for the resistance heating wire, the heating element 34 can be in a strip shape as shown in FIGS. 5 and 22, for example. Also, since the resistivity obtained from the high-TCR material alone is low, as exemplified in FIGS. 23 to 27, a zigzag shape combining parallel wiring and folded-back wiring is used, and the wiring width is made narrow and the wiring length is made several times longer by the number of fold-backs to increase the resistance value, thereby obtaining the calorific value required for a practical heater. In the zigzag-shaped resistance heating wire, it is preferable that the film thickness and width of the wiring are substantially the same within one heating cell. Also, it is preferable that they are substantially the same between different heating cells. Of course, in each heating cell, the film thickness and wiring width may be changed as needed, for example, to provide a temperature gradient or increase the strength as appropriate. For example, as shown in FIGS. 24 and 27, the connection portion 341 between the heating element 34 and the power supply line 35, the connection portion 342 between the bent portion 39 of the parallel portion 38 on the inner peripheral side of the flow path 25, and the central portion 343 located at the center of the flow path 25 on the substrate 31 can have a thickened film thickness because the printing becomes thin or the temperature change is large. Also, in order to suppress local temperature rise due to current concentration inside the corner portion and temperature unevenness due to resistance value variation of the heating element 34 in each cell 33, the connection portion 342 and the central portion 343 can be replaced with a conductive material having a smaller area specific resistance than the heating element 34, such as silver, so as to adjust the resistance value of each cell 33. By thickening the film thickness of such connection portions 341, 342 and the central portion 343 or selecting a conductive material, breakage of the resistance heating wire can be prevented.

[0039] As the material of the resistance heating wire constituting the heating cell, a conductive material capable of generating heat according to the resistance value by energization can be used. This conductive material is not limited, but for example, silver, copper, gold, platinum, palladium, rhodium, tungsten, molybdenum, rhenium (Re), ruthenium (Ru), etc. can be used. These may be used alone or in combination of two or more. When two or more are used in combination, they can be made into an alloy. More specifically, silver-palladium alloy, silver-platinum alloy, platinum-rhodium alloy, silver-ruthenium, silver, copper, gold, etc. can be used.

[0040] Each heating cell may have any resistance heating characteristics, but it is preferable that each heating cell can exhibit a self-temperature equalizing action (self-temperature compensating action). From that viewpoint, the conductive material constituting the resistance heating wire preferably has a positive temperature coefficient of resistance. Specifically, the temperature coefficient of resistance in the temperature range of -200°C or more and 1000°C or less is preferably 100 ppm / °C or more and 4400 ppm / °C or less, more preferably 300 ppm / °C or more and 3700 ppm / °C or less, and particularly preferably 500 ppm / °C or more and 3000 ppm / °C or less. Examples of such materials include silver-based alloys such as silver-palladium alloy. When a plurality of resistance heating wires (i.e., heating cells) formed using a conductive material (PTC material) having a positive temperature coefficient of resistance are electrically connected in parallel, these plurality of heating cells exhibit the effect of self-temperature equalization. That is, for example, when there is a second heating cell sandwiched between the first heating cell and the third heating cell, when the temperature of the second heating cell decreases, heat is supplemented from the first heating cell and the third heating cell. As a result of this heat supplementation, the current flowing through the first heating cell and the third heating cell with decreased temperature increases, and an action to autonomously recover from the temperature decrease due to the stolen heat works. That is, the heating cells around the second heating cell act to complement the temperature decrease of the second heating cell. Thus, a heater including a plurality of resistance heating wires formed using a conductive material having a positive temperature coefficient of resistance is autonomously controlled to heat uniformly across the plurality of heating cells.

[0041] Looking at a general metal material used for the resistance heating wire of the heater, for example, when silver (at 20 °C, resistivity ρ = 1.62×10 -8 Ωm, temperature coefficient α = 4.1×10 -3 / °C) is used, although the temperature coefficient α is large, it is difficult to obtain a high resistance value because the resistivity ρ is small. Therefore, palladium (ρ = 10.8×10 -8 Ωm, α = 3.7×10 -3 / °C), which has a larger resistivity ρ than silver, can be added, but even though the resistivity ρ increases, the temperature coefficient α decreases. Thus, when a material having high TCR characteristics is selected, the resistivity tends to be low. For this reason, to make the resistance heating wiring have a high TCR and a practical resistance value, it is necessary to increase the wiring length. By adopting a zigzag shape, the wiring length can be increased to increase the resistance value.

[0042] (Power supply line) The power supply wire (35) is a wiring for supplying the power supplied from the power supply terminal (36) to the heating cell (33), and usually uses a resistance heating wire with a low resistivity. As shown in FIGS. 5 and 23 to 26, the power supply wire 35 is directly connected to the power supply terminal 36. Also, as shown in FIG. 23, connection via other heating cells 33, that is, a state where a plurality of heating cells 33 are connected in series may be used. Here, when each heating cell 33 is individually powered from the power supply wire 35 disposed along the flow path 25, the power supplied to the heating cell 33 can be individually adjusted without being affected by other heating cells 33, and it can contribute greatly to the heating of the fluid by the entire heater unit.

[0043] (Power supply terminal) The power supply terminal (36) is composed of a low-resistance resistance heating wire or the like formed on the substrate (31). The power supply terminal 36 is usually formed on one surface of the same substrate 31 as the heating element 32. At least a pair of power supply terminals 36 are provided. Also, when individually supplying power to each heating element 32 in the case of having a plurality of heating elements 32, power supply terminals 36 are respectively provided. At this time, some of the power supply terminals 36 may be common to a plurality of heating elements 32.

[0044] (Insulating layer) The insulating layer (37) is a layer that insulates the heating element on the substrate 31 so that the heating element 32 does not come into contact with the outside air, fluid, or the like. Thereby, the heating element 32 can be protected and the fluid can be heated more efficiently. The material of the insulating layer 37 is not particularly limited, but for example, glass, ceramics, glass-ceramics, etc. are preferable. Among these, when using a metal (such as stainless steel) as the material constituting the substrate 31, the material of the insulating layer 37 is preferably glass, more preferably crystallized glass and semi-crystallized glass, from the viewpoint of its thermal expansion balance. Specifically, SiO2-Al2O3-MO-based glass is preferable. Here, MO is an oxide of an alkaline earth metal (MgO, CaO, BaO, SrO, etc.). The thickness of the insulating layer 37 is not particularly limited (for example, about 30 to 200 μm).

[0045] (Others) Temperature sensors, fluid detection sensors, fuses, etc. may be provided on the substrate 31.

[0046] (Heater Unit) The heater units 1A to 1G according to the present embodiment include a base 21 and the heater 3 that heats the fluid to be heated (i.e., coolant) flowing through the flow path 25 formed on the upper surface of the base 21. The applications of the heater units 1A to 1G are not particularly limited. For example, they can be used as heater units for battery temperature management or heating in vehicles (e.g., automobiles, railway vehicles, airplanes, ships, etc.). In particular, they can be suitably used as heater units for battery temperature management or heating in battery electric vehicles (BEV), fuel cell electric vehicles (FCEV), plug-in hybrid electric vehicles (PHEV), and hybrid electric vehicles (HEV).

Example

[0047] Hereinafter, the present invention will be specifically described with reference to Examples 1 to 7. In Examples 1 to 7, as the "heater unit" according to the present invention, a heater unit (also referred to as a "coolant heater") used for battery temperature management in battery electric vehicles (BEV), fuel cell electric vehicles (FCEV), etc. is exemplified.

[0048] <Example 1> As shown in FIGS. 1 to 4, the heater unit 1A according to Example 1 includes a base 21 and a heater 3 that heats the fluid to be heated (i.e., coolant) flowing through the flow path 25 formed on the upper surface 24 of the base 21.

[0049] The flow path 25 is open on the upper surface 24 of the base 21. The flow path 25 is a meandering flow path formed by alternately arranging a straight flow path that flows in a straight line direction and a curved flow path that reverses the flow direction. The base 21 has a fluid inlet 26a and an outlet 26b that are continuous with the flow path 25. The base 21 is made of metal such as aluminum die-casting and is formed in a rectangular shape in plan view. The base 21 is housed in a box-shaped lower cover 22 that is open upward and is covered by a box-shaped upper cover 23 that is open downward.

[0050] The heater 3 includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one surface side of the substrate 31 (specifically, the surface side opposite to the surface of the substrate 31 facing the flow path 25), and a power supply line 35 disposed on one surface side of the substrate 31 along the flow path 25. A pair of power supply lines 35 connected to the heating element 32 are provided on the substrate 31. Further, an insulating layer 37 is provided on one surface side of the substrate 31 to cover the heating element 32. In FIG. 4, a state where the heating element 32 is separated from the insulating layer 37 is shown, but usually, the heating element 32 is disposed in the middle part in the thickness direction of the insulating layer 37 (see FIG. 3).

[0051] The heating element 32 has a plurality of heating cells 33 that are individually powered. Each heating cell 33 is arranged side by side along the flow path 25 from the inlet 26a toward the outlet 26b. Each heating cell 33 is formed using a conductive material having a positive temperature coefficient of resistance. Each heating cell 33 is electrically connected in parallel to a pair of power supply lines 35. As the heating element 32, any of the forms shown in FIGS. 22 to 28 can be used instead of the form shown in FIG. 5.

[0052] Next, the operation and effect of the heater unit 1A with the above configuration will be described. The fluid to be heated is circulated between the heater unit 1A and a battery unit (not shown). In the heater unit 1A, the fluid to be heated flowing into the flow path 25 from the inlet 26a is heated by the heater 3 and then sent from the outlet 26b to the battery unit, and the operating temperature of the battery is optimally maintained.

[0053] As described above, according to the heater 3 of the first embodiment, there are a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one side of the substrate 31, and a power supply line 35 disposed on one side of the substrate 31 along the flow path 25. The heating element 32 has a plurality of heating cells 33 that are each supplied with power. The plurality of heating cells 33 are connected in parallel to the power supply line 35, and the plurality of heating cells 33 are arranged side by side along the flow path 25 from the inlet 26a provided in the base 21 toward the outlet 26b. Thereby, the fluid to be heated flowing through the flow path 25 is heated by the plurality of heating cells 33 that are each supplied with power by being connected in parallel to the power supply line 35. As a result, each heating cell 33 can generate heat without being affected by the amount of current flowing through other heating cells, and it is difficult for uneven heating to occur due to the heating of other heating cells. Therefore, it is possible to prevent or suppress the occurrence of uneven heating caused by a part becoming high temperature due to heating the entire flow path with a heating resistor extending along the flow path, which has occurred in conventional fluid heaters. As a result, the fluid to be heated can be heated evenly and efficiently throughout the entire flow path 25 corresponding to various fluid forms (for example, fluid velocity, fluid temperature, etc.).

[0054] In particular, in the first embodiment, a plurality of heating cells 33 formed of a conductive material having a positive temperature coefficient of resistance are electrically connected in parallel. Thereby, since each heating cell 33 effectively exhibits the function of self-temperature balance, the fluid to be heated can be heated more evenly and efficiently throughout the entire flow path 25 corresponding to various fluid forms.

[0055] <Embodiment 2> Next, the heater unit 1B according to Example 2 will be described with reference to FIGS. 6 and 7. The same reference numerals are given to substantially the same components as those of the heater unit 1A according to Example 1, and detailed description thereof will be omitted.

[0056] The heater unit 1A according to the present Example 2 includes a base 21 and a heater 3 that heats a fluid to be heated (i.e., a coolant) flowing through a flow path 25 formed on the upper surface 24 of the base 21.

[0057] The heater 3 includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one surface side of the substrate 31 (specifically, the surface side opposite to the surface of the substrate 31 facing the flow path 25), and a power supply line 35 disposed on one surface side of the substrate 31 along the flow path 25. Further, an insulating layer 41 (exemplified as a "reinforcing layer") is disposed on the surface side of the substrate 31 facing the flow path 25 along the flow path 25. The insulating layer 41 is formed of glass.

[0058] As described above, according to the heater unit 1B of the present Example 2, in addition to exhibiting substantially the same operational effects as those of the heater unit 1A of Example 1, an insulating layer 41 is disposed on the surface side of the substrate 31 facing the flow path 25 along the flow path 25. Therefore, it is possible to reduce the thickness (i.e., weight) of the substrate 31 and suppress warping of the substrate 31. More specifically, when the substrate 31 is made of steel, in existing products, since the substrate 31 is 3 mm thick and has a large heat capacity, it takes time for the fluid to warm up. Therefore, by providing the insulating layer (glass) 41 on the opposite side of the heater 3 surface, even if the thickness of the metal substrate 31 is reduced to 0.6 mm to 0.2 mm, the substrate 31 will not warp, the heat capacity can be reduced, and the heater 3 can have quick response characteristics for raising and lowering the temperature (i.e., the efficiency of fluid heating can be improved). In addition, in the present Example 2, as the reinforcing layer, instead of the insulating layer 41, a heat dissipation layer formed of a material having a higher thermal conductivity than the material (such as stainless steel) constituting the substrate 31 (such as silver, copper, aluminum, etc.) may be employed.

[0059] <Example 3> Next, the heater unit 1C according to Example 3 will be described with reference to FIGS. 8 to 10. The same reference numerals are given to substantially the same component parts as those of the heater unit 1B according to Example 2, and the detailed description thereof will be omitted.

[0060] The heater unit 1C according to the present Example 3 includes a base 21 and a heater 3 that heats a fluid to be heated (i.e., a coolant) flowing through a flow path 25 formed on the upper surface 24 of the base 21.

[0061] The heater 3 includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one surface side of the substrate 31 (specifically, the surface side opposite to the surface of the substrate 31 facing the flow path 25), and a power supply line 35 disposed on one surface side of the substrate 31 along the flow path 25. Further, an insulating layer 41 (exemplified as a "reinforcing layer") is disposed on the surface side of the substrate 31 facing the flow path 25 along the flow path 25.

[0062] The insulating layer 41 is formed with an exposed portion 42 that communicates the surface side of the substrate 31 facing the flow path 25 with the flow path 25. The exposed portion 42 is formed in a long shape along the flow path 25. Specifically, the exposed portion 42 is formed in a meandering shape corresponding to the meandering flow path 25.

[0063] As described above, according to the heater unit 1C of the present Example 3, in addition to exhibiting substantially the same operational effects as the heater unit 1B of Example 2, the insulating layer 41 is formed with an exposed portion 42 that communicates the surface side of the substrate 31 facing the flow path 25 with the flow path 25, so that the heat exchange efficiency can be further improved. More specifically, the insulating layer (glass) 41 on the surface opposite to the surface of the heater 3 is in contact with water. Since glass has poor thermal conductivity, providing the exposed portion 42 improves the heat conduction efficiency. That is, the back surface glass 41 is provided to reduce the heat capacity, but since the back surface glass 41 has a lower thermal conductivity than metal, the exposed portion 42 where metal is exposed is provided to facilitate heat transfer to the fluid.

[0064] Here, instead of the above-mentioned insulating layer 41 (see FIG. 9), as shown in FIG. 11, an insulating layer 41 in which a plurality of exposed portions 42 such as V-shaped or dot-shaped in plan view are formed along the flow path 25 can be used. In this case, since turbulence is generated in the fluid to be heated flowing through the flow path 25 by the large number of exposed portions 42, the heat exchange efficiency can be further improved. In addition, in the third embodiment, as the reinforcing layer, instead of the insulating layer 41, a heat sink layer formed of a material (such as silver, copper, aluminum, etc.) having a higher thermal conductivity than the material (such as stainless steel, etc.) constituting the substrate 31 may be adopted.

[0065] <Example 4> Next, with reference to FIGS. 12 to 14, the heater unit 1D according to the fourth embodiment will be described. The same reference numerals are given to substantially the same component parts as those of the heater unit 1C according to the third embodiment, and the detailed description thereof will be omitted.

[0066] The heater unit 1D according to the fourth embodiment includes a base 21 and a heater 3 that heats a fluid to be heated (i.e., a coolant) flowing through a flow path 25 formed on the upper surface 24 of the base 21.

[0067] The heater 3 includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one surface side of the substrate 31 (specifically, the surface side opposite to the surface of the substrate 31 facing the flow path 25), and a power supply line 35 disposed on one surface side of the substrate 31 along the flow path 25. Further, on the surface side of the substrate 31 facing the flow path 25, an insulating layer 41 (exemplified as a "reinforcing layer") is disposed along the flow path 25.

[0068] An exposed portion 42 that communicates the surface side of the insulating layer 41 facing the flow path 25 of the substrate 31 with the flow path 25 is formed in the insulating layer 41. A heat sink 43 that protrudes into the flow path 25 through the exposed portion 42 is disposed on the surface side of the substrate 31 and the insulating layer 41 facing the flow path 25. The heat sink 43 includes a bonding plate 43a joined to the surface side of the substrate 31 facing the flow path 25, and a heat dissipation plate 43b protruding from one surface of the bonding plate 43a into the flow path 25. The heat dissipation plate 43b is formed in a long shape along the flow path 25.

[0069] As described above, according to the heater unit 1D of the present Example 4, in addition to achieving substantially the same operational effects as the heater unit 1C of Example 3, a heat sink 43 that protrudes into the flow path 25 via the exposed portion 42 is disposed on the surface side of the substrate 31 that faces the flow path 25. Therefore, the heat exchange efficiency can be further improved, and the warping of the substrate 31 can be more effectively suppressed.

[0070] Here, instead of the above heat sink 43 (see FIG. 13), a heat sink 43 (see FIGS. 15(a) and (b)) having a plurality of heat dissipation plates 43b formed at predetermined intervals along the flow path 25 can be used. In this case, since the heated fluid flowing on both the left and right sides of the heat dissipation plate 43b intersects through the gaps between adjacent heat dissipation plates 43b, further temperature equalization of the heated fluid can be achieved throughout the flow path 25.

[0071] In particular, when using a heat sink 43 (see FIG. 15(b)) having a plurality of heat dissipation plates 43b with one side inclined with respect to the axial direction of the flow path 25, by making the adjacent heat dissipation plates 43b have fin structures with different angles, it becomes easier to generate turbulent flow of the heated fluid, and further temperature equalization of the heated fluid can be achieved throughout the flow path 25.

[0072] Furthermore, instead of the above heat sink 43 (see FIG. 13), a heat sink 43 (see FIG. 15(c)) having a plurality of heat dissipation plates 43b arranged opposite to each other (i.e., arranged side by side in the width direction of the flow path 25) can be used. In this case, since the contact area between the heat sink 43 and the heated fluid increases, the heat exchange efficiency can be further improved. In addition, in the present Example 4, as the reinforcing layer, instead of the insulating layer 41, a temperature equalizing layer formed of a material (such as silver, copper, aluminum, etc.) having a higher thermal conductivity than the material (such as stainless steel, etc.) constituting the substrate 31 may be employed.

[0073] <Example 5> Next, the heater unit 1E according to Example 5 will be described with reference to FIGS. 16 and 17. The same reference numerals are given to substantially the same constituent parts as those of the heater unit 1C according to Example 3, and detailed description thereof will be omitted.

[0074] The heater unit 1E according to the present Example 5 includes a base 21 and a heater 3 that heats a fluid to be heated (i.e., a coolant) flowing through a flow path 25 formed on the upper surface 24 of the base 21.

[0075] The heater 3 includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one surface side of the substrate 31 (specifically, the surface side opposite to the surface of the substrate 31 facing the flow path 25), and a power supply line 35 disposed on one surface side of the substrate 31 along the flow path 25. Further, an insulating layer 41 (exemplified as a "reinforcing layer") is disposed on the surface side of the substrate 31 facing the flow path 25 along the flow path 25.

[0076] The insulating layer 41 is formed with an exposed portion 42 that communicates the surface side of the substrate 31 facing the flow path 25 with the flow path 25. A heat dissipation layer 44 (exemplified as a "reinforcing layer") is disposed between the substrate 31 and the insulating layer 41 so as to be exposed to the flow path 25 through the exposed portion 42. Further, the heat dissipation layer 44 is formed of a material (such as silver, copper, or aluminum) having a higher thermal conductivity than the material (such as stainless steel) constituting the substrate 31. Note that the form shown in FIG. 11 may be used as the exposed portion 42.

[0077] As described above, according to the heater unit 1E of the present Example 5, in addition to exhibiting substantially the same operational effects as those of the heater unit 1C of Example 3, a heat dissipation layer 44 that is exposed to the flow path 25 through the exposed portion 42 is disposed between the substrate 31 and the insulating layer 41, and the heat dissipation layer 44 is formed of a material having a higher thermal conductivity than the material constituting the substrate 31. Therefore, the heat exchange efficiency can be further improved, and the warping of the substrate 31 can be more effectively suppressed.

[0078] <Example 6> Next, the heater unit 1F according to Example 6 will be described with reference to FIGS. 18 and 19. The same reference numerals are given to substantially the same component parts as those of the heater unit 1C according to Example 3, and detailed description thereof will be omitted.

[0079] The heater unit 1F according to Example 6 of the present embodiment includes a base 21 and a heater 3 that heats a fluid to be heated (i.e., a coolant) flowing through a flow path 25 formed on the upper surface 24 of the base.

[0080] The heater 3 includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on one surface side of the substrate 31 (specifically, the surface side opposite to the surface of the substrate 31 facing the flow path 25), and a power supply line 35 disposed on one surface side of the substrate 31 along the flow path 25. Further, an insulating layer 41 (exemplified as a "reinforcing layer") is disposed on the surface side of the substrate 31 facing the flow path 25 along the flow path 25.

[0081] The insulating layer 41 is formed with an exposed portion 42 that communicates the surface side of the substrate 31 facing the flow path 25 with the flow path 25. An embedded member 45 is embedded in the exposed portion 42. The embedded member 45 is formed of a material (such as silver, copper, or aluminum) having a higher thermal conductivity than the material (such as stainless steel) constituting the substrate 31. Note that, as the exposed portion 42, the form shown in FIG. 11 may be used. In this case, an embedded member 45 corresponding to the shape of each exposed portion 42 is embedded in each of the plurality of exposed portions 42.

[0082] As described above, according to the heater unit 1F of Example 6 of the present embodiment, in addition to exhibiting substantially the same operational effects as the heater unit 1C of Example 3, the exposed portion 42 is embedded with an embedded member 45 formed of a material having a higher thermal conductivity than the material constituting the substrate 31. Therefore, the heat exchange efficiency can be further improved, and the warping of the substrate 31 can be more effectively suppressed. In addition, in Example 6 of the present embodiment, as the reinforcing layer, a soaking layer formed of a material (such as silver, copper, or aluminum) having a higher thermal conductivity than the material (such as stainless steel) constituting the substrate 31 may be employed instead of the insulating layer 41.

[0083] <Example 7> Next, the heater unit 1G according to Example 7 will be described with reference to FIGS. 20 and 21. The same reference numerals are given to substantially the same component parts as those of the heater unit 1A according to Example 1, and detailed description thereof will be omitted.

[0084] The heater unit 1G according to the present Example 7 includes a base 21 and a heater 3 that heats a fluid to be heated (i.e., a coolant) flowing through a flow path 25 formed on the upper surface 24 of the base 21.

[0085] The heater 3 includes a substrate 31 disposed so as to cover the upper surface 24 of the base 21, a heating element 32 disposed on the surface side of the substrate 31 facing the flow path 25, and a power supply line 35 disposed on the surface side of the substrate 31 facing the flow path 25 along the flow path 25. Further, a power supply terminal 36 electrically connected to the heating element 32 via the power supply line 35 is disposed on the surface side of the substrate 31 facing the flow path 25. Furthermore, a sealing and heat dissipation layer 46 is disposed on the surface side of the substrate 31 facing the flow path 25 so as to seal the flow path 25. The power supply terminal 36 does not overlap with the sealing and heat dissipation layer 46 in the thickness direction of the substrate 31 and is open via a space. The power supply terminal 36 is connected to a lead wire 49 by soldering and an insulating mold 48 or the like.

[0086] The sealing and heat dissipation layer 46 is formed of a material (such as silver, copper, aluminum, etc.) having a higher thermal conductivity than the material (such as stainless steel, etc.) constituting the substrate 31. Further, a thermal conductive grease layer or a thermal conductive adhesive layer 47 is disposed between the substrate 31 and the sealing and heat dissipation layer 46.

[0087] As described above, according to the heater unit 1G of the present Example 7, in addition to exhibiting substantially the same operational effects as those of the heater unit 1A of Example 1, since the heating element 32 is disposed on the surface side of the substrate 31 facing the flow path 25, the heat exchange efficiency can be further improved.

[0088] In addition, in the seventh embodiment, a power supply terminal 36 electrically connected to the heating element 32 is disposed on the surface side of the substrate 31 facing the flow path 25, and a sealing heat dissipation layer 46 is disposed on the surface side of the substrate 31 facing the flow path 25 so as to seal the flow path 25. The sealing heat dissipation layer 46 is formed of a material having a higher thermal conductivity than the material constituting the substrate 31. Thereby, the heat exchange efficiency can be further improved, and the warping of the substrate 31 can be more effectively suppressed.

[0089] Furthermore, in the seventh embodiment, a heat conductive grease layer or a heat conductive adhesive layer 47 is disposed between the substrate 31 and the sealing heat dissipation layer 46. Thereby, the heat exchange efficiency can be further improved.

[0090] <Flow-through heating experiment> Next, the flow-through heating experiment will be described. As shown in FIG. 29, the experimental system used in this flow-through heating experiment includes a heater unit 51, a tank 52 for storing flowing water, and a pump 53 for circulating the flowing water. These heater unit 51, tank 52, and pump 53 are connected via a hose 54. In addition, thermometers 55 are disposed at the inlet 26a and the outlet 26b of the heater unit 51, respectively. A thermo viewer (camera) 56 is disposed above the heater unit 51.

[0091] As shown in FIG. 30, the heater unit 51 has an aluminum square pipe 57 (20 mm × 20 mm × 500 mm, thickness 2 mm). The inlet 26a is attached to one axial end of the square pipe 57, and the outlet 26b is attached to the other axial end. In addition, a hole (10 mm × 325 mm) is formed in the upper surface of the square pipe 57. Further, a heater 58A or a heater 58B described later can be installed on the upper surface of the square pipe 57 so as to close the hole 57a.

[0092] The heater 58A of the experimental example used in this flowing water heating experiment has, as shown in Fig. 31(a), a long substrate 31 and a heating element 32 disposed on one side of the substrate 31. The heating element 32 has a plurality (five in the figure) of heating cells 33 that are each supplied with power. Each heating cell 33 is arranged side by side along the flow path 25 from the inlet 26a to the outlet 26b. That is, each heating cell 33 constitutes a parallel circuit.

[0093] On the other hand, the heater 58B of the comparative example used in this flowing water heating experiment has, as shown in Fig. 31(b), a long substrate 31 and a heating element 32 disposed on one side of the substrate 31. The heating element 32 has a plurality (two in the figure) of heating cells 33 that are each supplied with power. Each heating cell 33 extends along the flow path 25 from the inlet 26a to the outlet 26b. That is, each heating cell 33 constitutes a series circuit.

[0094] As shown in Fig. 32, on each of one side and the other side of the substrate 31 of the heaters 58A and 58B, an insulating glass layer 61, a protective glass layer 62, and an overcoat layer 63 are laminated in that order. The total thickness of these three layers 61 to 63 is 200 μm. The substrate 31 of the heater 58A has a width of 11.9 mm, a thickness of 0.6 mm, a length of 407 mm, and a heating effective length of 324 mm. On the other hand, the substrate 31 of the heater 58B has a width of 12 mm, a thickness of 0.6 mm, a length of 376 mm, and a heating effective length of 322 mm. Note that the heaters 58A and 58B have basically the same design, and although the substrate lengths are different, it was judged that the influence on the heating efficiency was small, and an experiment was conducted.

[0095] In this flowing water heating experiment, a heater 58A or a heater 58B was installed on the upper surface of the square pipe 57, water was flowed through the square pipe 57 at a flow rate of 1 L / min, the heater 58A or the heater 58B was controlled at 110°C, and heating was performed at a predetermined voltage (675 W, 1012.5 W, 1350 W, 1500 W), and the difference in the inlet temperature at the start of heating and 10 minutes after the start of heating was measured. As a result, at 675 W, the series circuit heater 58B showed a higher temperature than the parallel circuit heater 58A, whereas the relationship reversed at 1000 W and the rising temperature of the series circuit heater 58B became lower than that of the parallel circuit heater 58A. This is considered to be because as the output to the heater increased, local heat generation was accelerated in the series circuit heater 58B, water boiled (phase transition from the liquid phase to the gas phase) on the back surface of the heater, bubbles were generated, and the heat exchange between the heater and water was partially reduced in efficiency, resulting in a decrease in the overall water temperature rise. On the other hand, in the parallel circuit heater 58A, it is considered that the self-temperature compensation mechanism worked, local heating was avoided, and water did not boil on the back surface of the heater, so the amount of water temperature rise was maintained.

[0096] From the above, it was confirmed that the heater 58A in the experimental example in which the heating cell 33 constitutes a parallel circuit (that is, the heater 58A having a self-temperature compensation function) has higher heat exchange efficiency than the heater 58B in the comparative example in which the heating cell 33 constitutes a series circuit (that is, the heater 58B not having a self-temperature compensation function).

[0097] In addition, in the present invention, the present invention is not limited to those shown in the above specific examples, and various modified examples within the scope of the present invention can be provided according to the purpose and application. For example, a heater unit can be configured by combining two or more of Examples 1 to 7.

Explanation of Reference Numerals

[0098] 1A to 1G; heater unit, 21; base, 22; lower cover, 23; upper cover, 24; flow path forming surface, 25; flow path, 26a; inlet, 26b; outlet 3; Heater, 31; Substrate, 32; Heating element, 33, 331, 332, 333; Heating cell, 34; Heating element, 341, 342; Connection part, 343; Central part, 35; Power supply line, 36; Power supply terminal, 37; Insulation layer, 38, 381; Parallel part, 39, 391; Bending part, 41; Insulation layer, 42; Exposed part, 43; Heat sink, 44; Soaking layer, 45; Embedded member, 46; Sealed soaking layer, 51; Heater unit, 52; Tank, 53; Pump, 54; Hose, 55; Thermometer, 56; Thermoviewer, 57; Angle pipe, 58A; Heater of experimental example, 58B; Heater of comparative example, 61; Insulating glass layer, 62; Protective glass layer, 63; Overcoat layer.

Claims

1. A heater for heating a fluid to be heated flowing through a flow path formed on an upper surface of a base, comprising: a substrate disposed so as to cover the upper surface of the base; a heating element disposed on one surface side of the substrate; and a power supply line disposed on one surface side of the substrate along the flow path. The heating element has a plurality of heating cells each receiving power supply separately. The plurality of heating cells are connected in parallel to the power supply line. The plurality of heating cells are arranged side by side along the flow path from an inlet provided in the base toward an outlet. A heater characterized by this.

2. The heater according to claim 1, wherein the resistance heating wire constituting the heating element is formed of a material having a high resistance temperature coefficient and / or a PTC material.

3. The heater according to claim 1 or 2, wherein a reinforcing layer is disposed on a surface side of the substrate facing the flow path along the flow path.

4. The heater according to claim 3, wherein an exposed portion communicating the surface side of the substrate facing the flow path and the flow path is formed in the reinforcing layer.

5. The heater according to claim 4, wherein a heat sink protruding into the flow path through the exposed portion is disposed on a surface side of the substrate facing the flow path.

6. The heater according to claim 4, wherein an embedded member formed of a material having a higher thermal conductivity than the material constituting the substrate is embedded in the exposed portion.

7. The heater according to claim 3, wherein the reinforcing layer is an insulating layer.

8. The heater according to claim 3, wherein the reinforcing layer is a heat dissipation layer formed of a material having a higher thermal conductivity than the material constituting the substrate.

9. The heater according to claim 1 or 2, wherein the substrate is formed of a clad material or a bimetal.

10. The heater according to claim 1 or 2, further comprising an insulating layer disposed on one surface side of the substrate to cover the heating element.

11. The heater according to claim 1 or 2, wherein the heating element is formed by printing a resistance heating wire on the substrate.

12. The heater according to claim 1 or 2, wherein the heating cell is constituted by a zigzag curved shape including a parallel portion formed in a direction orthogonal to the flow direction of the flow path and a bent portion connecting adjacent parallel portions.

13. The heater according to claim 1 or 2, wherein the heating cell is formed in a zigzag curved shape including a parallel portion formed in a direction parallel to the flow direction of the flow path and a bent portion connecting adjacent parallel portions.

14. A heater unit including a base and a heater that heats a fluid to be heated flowing through a flow path formed on an upper surface of the base. The heater unit is characterized in that the heater is the heater according to any one of claims 1 to 13.

Images