Liquid heating device

Abstract

To provide a liquid heating device that suppresses thermal deformation and liquid leakage at a portion between a ceramic heater and a container.SOLUTION: A liquid heating device 200 includes a container surrounding an interior space 100i and having an opening 107m1 to 107m3, ceramic heaters 171 to 173 that extends in the front-rear direction L and penetrates through the opening, and has a tip portion 17T in which a base end portion 17R is located outside the internal space, and that has a heat generating portion 17a at the end, and a fixing member 180 that fixes the ceramic heater to the container while sealing the gap between the opening and the ceramic heater, and heats a liquid W in the internal space with the ceramic heater, and the liquid is introduced into the internal space from the outside through a channel 103i penetrating through the fixing member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a liquid heating device that produces hot water or the like using a ceramic heater. [Background technology]

[0002] Hot water is required for warm water washing toilet seats, fuel cell systems, water heaters, 24-hour baths, heating of vehicle washer fluid, in-vehicle air conditioners, etc. For this reason, liquid heating devices that heat water using a built-in heater are used (Patent Document 1). In particular, to rapidly heat hot water for warm water washing toilet seats and to miniaturize liquid heating devices, rod-shaped ceramic heaters are used in which a heating element is embedded in a ceramic sheet wrapped around the outer periphery of a long, thin ceramic base. The tip end of this ceramic heater is placed inside the container through an opening in the side wall of the container of the liquid heating device, and the base end is exposed to the outside. The ceramic heater also has an inner hole that passes through it in the longitudinal direction, and water to be heated is introduced into the container from the base end exposed to the outside through the inner hole, heated by the inner and outer surfaces of the ceramic heater, and discharged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-51546 A (Fig. 4) Summary of the Invention [Problem to be solved by the invention]

[0004] However, as the size of liquid heating devices is being demanded, ceramic heaters are also becoming smaller. However, when ceramic heaters are made smaller (reduced in diameter), the diameter of their inner holes also becomes smaller, making it difficult for water to pass through the holes. Therefore, if a structure is adopted in which heating is performed only on the outer surface of the heater without passing water through the inner bore, the heater will overheat because the inner bore of the heater will not be cooled by the heated water, and there is a risk that the seal in the gap between the heater and the container or the container components will be thermally deformed, or water leakage will occur.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a liquid heating device that suppresses thermal deformation and liquid leakage in the area between the ceramic heater and the container. [Means for solving the problem]

[0006] In order to solve the above problems, a liquid heating device according to a first aspect of the present invention includes a container surrounding an internal space and having an opening; a ceramic heater extending in a front-to-rear direction and penetrating the opening, with its tip end located within the internal space and its base end located outside the internal space, and having a heat generating portion at the tip end; and a fixing member that fixes the ceramic heater to the container while sealing a gap between the opening and the ceramic heater. A liquid heating device that heats a liquid in the internal space by the ceramic heater, the container further includes a front end cap separate from the fixing part, the front end cap closing the opening, the base end of the ceramic heater passing through the front end cap and having a flow path, the fixing part covering at least a portion of the flow path of the front end cap; The liquid is The above The liquid is introduced into the internal space through a flow path.

[0007] In this liquid heating device, the flow path penetrates the fixing member from the outside, so the fixing member is cooled by the unheated liquid passing through the flow path. Therefore, by adopting a structure in which heating is performed only on the outer surface of the ceramic heater without passing liquid through the inner hole, overheating of the fixing member around the ceramic heater is suppressed even when the heating temperature of the heater becomes high, which in turn suppresses thermal deformation of the container in contact with the fixing member and prevents leakage of liquid between the ceramic heater and the container.

[0008] A liquid heating device according to a second aspect of the present invention comprises a container having a wall surrounding an internal space, and a ceramic heater extending in a front-to-rear direction and penetrating the wall, with a tip end located within the internal space and a base end located outside the internal space, the ceramic heater having a heat generating portion at the tip end, and heating a liquid in the internal space by the ceramic heater, wherein the ceramic heater is fixed to the wall, a wall through which the ceramic heater is fixed, the wall having a flow path formed therethrough so as to overlap a region of the fixed portion of the ceramic heater along the front-rear direction; The liquid is supplied from the outside. The above The liquid is introduced into the internal space through a flow path.

[0009] In this liquid heating device, the flow path penetrates the wall from the outside, so the wall is cooled as the unheated liquid passes through the flow path. Therefore, by adopting a structure in which heating is performed only on the outer surface of the ceramic heater without passing the liquid through the inner hole, thermal deformation of the wall around the ceramic heater is suppressed even when the heater's heating temperature becomes high, and leakage of liquid between the ceramic heater and the container can be suppressed.

[0010] In the liquid heating device of the present invention, the wall and the ceramic heater may be in close contact with each other without any gap therebetween. This liquid heating device is easy to manufacture and can more reliably prevent liquid from leaking between the container and the ceramic heater.

[0011] In the liquid heating device of the present invention, the ceramic heater may have an outer diameter of 5 mm or less. If the outer diameter of the ceramic heater is 5 mm or less, even if an inner hole is provided in the ceramic heater, the inner hole will have a small diameter, making it difficult to introduce liquid and the ceramic heater will easily overheat, making the present invention more effective.

[0012] The liquid heating device of the present invention has a plurality of ceramic heaters spaced apart from each other and extending in the front-to-rear direction, and the flow path extends in the front-to-rear direction. From the perspective It may be formed between at least two ceramic heaters. According to this liquid heating device, it is possible to effectively cool the area between the two ceramic heaters that sandwich the flow path, where heat tends to accumulate.

[0013] In the liquid heating device of the present invention, an axial direction of an end portion of the flow channel that faces the internal space may be along the front-to-rear direction. According to this liquid heating device, the liquid flows easily on the outer surface of the ceramic heater in the front-to-back direction L in which the ceramic heater extends, so that it is possible to prevent the liquid from accumulating near the flow path and reducing the cooling effect. [Effects of the Invention]

[0014] According to this invention, a liquid heating device can be obtained that suppresses thermal deformation and liquid leakage in the area between the ceramic heater and the container. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing the appearance of a liquid heating device according to an embodiment of a first aspect of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the liquid heating device. [Figure 3] Cross-sectional view along line AA in Figure 1 [Figure 4] FIG. 2 is a perspective view showing the appearance of the ceramic heater. [Figure 5] FIG. 2 is an exploded perspective view showing the configuration of the ceramic heater. [Figure 6] FIG. 2 is a cross-sectional view of a liquid heating device according to an embodiment of the second aspect of the present invention. [Figure 7] FIG. 10 is a cross-sectional view of a modified example of the liquid heating device according to the second aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a perspective view of a liquid heating device 200 according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view of the liquid heating device 200, FIG. 3 is a cross-sectional view taken along line AA in FIG. 1, FIG. 4 is a perspective view of a ceramic heater 171, and FIG. 5 is an exploded perspective view of the ceramic heater 171.

[0017] In this embodiment, the liquid heating device 200 is installed in a warm-water washing toilet seat, and supplies warm water by heating room-temperature water with three built-in ceramic heaters 171 to 173.

[0018] The liquid heating device 200 has a container 100 that is generally triangular in shape (a cylinder with a triangular cross section) as a whole, and three ceramic heaters 171-173. The container 100 has an elongated cylindrical body 101 having an internal space 100i for accommodating liquid W (water), a front end cap 107 and a rear end cap 108 that close openings at both axial ends of the body 101, and an inlet 103 and an outlet 105 for the liquid W. The container 100 is made of, for example, resin.

[0019] The inlet 103 and outlet 105 are respectively formed integrally with the front end cap 107 and the body 101. The outer periphery of the front axial end of the body 101 (the end on the side where the ceramic heaters 171 to 173 in FIG. 1 are exposed) has a protruding portion 101p that protrudes axially outward along the contour, and the front end cap 107 can be housed inside this protruding portion 101p. On the other hand, the rear end in the axial direction of the body portion 101 projects radially in the form of a flange, and a rear end cap 108 is liquid-tightly sealed to this flange via a rubber seal such as a packing. In this manner, the internal space 100i is surrounded by the body 101, the front end cap 107, and the rear end cap 108 that constitute the container 100.

[0020] The three ceramic heaters 171-173 are each shaped like a rod extending in the front-to-rear direction L, and extend in the same direction (parallel to each other). The base end 17R of each of the ceramic heaters 171-173 penetrates three openings 107m1-107m3 of the front end cap 107. The gaps between the ceramic heaters 171-173 and the openings 107m1-107m3 are sealed with a fixing member 180 (see FIG. 2) made of epoxy resin, whereby the ceramic heaters 171-173 are fixed to the container 100 in a cantilevered manner. In this way, the tip portions 17T of the ceramic heaters 171 to 173 are positioned within the internal space 100i. It goes without saying that the position of the fixing member 180 is closer to the base end than the heat generating portion 17a of the ceramic heater, which will be described later. Furthermore, lead wires 15 and 16 (described later) are connected to the base end portion 17R of the ceramic heaters 171 to 173 for supplying power from the outside.

[0021] In this example, the axial direction of the body 101 is parallel to the front-to-back direction L, and the ceramic heaters 171 to 173 are housed in the internal space 100i of the body 101 so that the arrangement direction of the ceramic heaters 171 to 173 is along the axial direction of the body 101. Also, although not shown, in this example, the liquid heating device 200 is installed on the warm water washing toilet seat so that the front-to-back direction L is approximately horizontal and the outlet 105 side is positioned slightly above, and each ceramic heater 171 to 173 is placed horizontally.

[0022] The inlet 103 and the outlet 105 are connected to the internal space 100i and are spaced apart in the front-to-rear direction L (which is also the axial direction of the body 101). Liquid W introduced from the outside through the inlet 103 passes through the internal space 100i along the flow direction F and is discharged from the outlet 105. In addition, a gap is formed between the inner wall of the container 100 and the ceramic heaters 171-173, and the liquid W introduced into the internal space 100i through the inlet 103 is heated while coming into contact with the outer surfaces of the ceramic heaters 171-173 in the front-to-back direction L, and then flows to the outlet 105.

[0023] As shown in FIG. 2, the front end cover 107 includes a substantially triangular, plate-shaped flange portion 107f, three openings 107m1 to 107m3 respectively arranged in the flange portion 107f, a raised portion 107p, and an inlet 103 extending outward from the raised portion 107p. The three openings 107m1 to 107m3 are each located near one vertex of the flange portion 107f and form a circular hole. The raised portions 107p protrude outward from the flange portion 107f at positions inside the openings 107m1 to 107m3. The inlet 103 is connected to the raised portions 107p and extends from the raised portions 107p along the plate surface of the flange portion 107f beyond the outer periphery of the flange portion 107f. More specifically, the inlet 103 extends between the two adjacent openings 107m3 and 107m2 so as to intersect with one side of the flange portion 107f.

[0024] As shown in FIG. 3, the inner hole 103i (flow path for the liquid W) of the inlet 103 is bent inside the raised portion 107p so as to be approximately perpendicular to the plate surface of the flange portion 107f, and opens to the inner surface 107a of the flange portion 107f. On the other hand, a part of the protruding portion 101p of the container 100 is provided with a notch 101n (FIG. 2) for passing the inlet 103 therethrough. A fixing member 180 made of epoxy resin is filled not only in the gaps between the ceramic heaters 171 to 173 and the openings 107m1 to 107m3 but also so as to bury the front end cover 107.

[0025] Next, the configuration of the ceramic heater will be described with reference to Figures 4 and 5. Since the ceramic heaters 171 to 173 have the same shape, only the ceramic heater 171 will be described. 4, the ceramic heater 171 has a heating element 17h that generates heat when externally energized via lead wires 15 and 16. The heating element 17h has a heating portion 17a at its front end that is formed as a heating pattern by meandering a conductor in the front-to-rear direction L, and a pair of lead portions 17b that are drawn out from both ends of the heating portion 17a to the rear end side. The heat generating portion 17a has a length of Lh in the front-to-rear direction L.

[0026] More specifically, as shown in FIG. 5, the heating element 17h has a heating portion 17a, two lead portions 17b, and an electrode pattern 17c formed at the rear end of each lead portion 17b. The heating element 17h is sandwiched between two ceramic green sheets 17s1 and 17s2. The ceramic green sheets are made of alumina. The heating portion 17a and the lead portions 17b are made of tungsten, rhenium, or the like. Two electrode pads 17p to which lead terminals 18 (see FIG. 4) are brazed are formed on the surface of the ceramic green sheet 17s2. The electrode pattern 17c is connected to the electrode pads 17p via through-holes to form a laminate of ceramic green sheets.

[0027] Furthermore, by wrapping this laminate around a rod-shaped ceramic base 17g whose main component is alumina or the like with the ceramic green sheet 17s2 facing outward and firing it, the ceramic green sheets 17s1 and 17s2 become ceramic sheets 17s and are wrapped around the outer periphery of the ceramic base 17g to produce an integrated ceramic heater 171. The lead wires 15 and 16 are crimped to lead terminals 18 and electrically connected to them (see FIG. 4). In this example, the ceramic substrate 17g is solid, but it may be cylindrical, in which case it is desirable to seal the through-holes with resin or the like to prevent water from leaking.

[0028] Here, when the laminate is wound around the ceramic base 17g, a gap is left between both ends of the laminate along the front-to-back direction L. For this reason, a slit 17v, which serves as a recessed groove along the front-to-back direction L, is formed as a non-heat-generating portion in the wound portion on the outer surface of the ceramic heater 171.

[0029] Next, returning to FIG. 3, the characteristic parts of the liquid heating device 200 according to the embodiment of the first aspect will be described. As shown in FIG. 3, the fixing member 180 is filled on the outside of the front end cap 107, thereby fixing the ceramic heaters 171 to 173 to the container 100 (openings 107m1 to 107m3) while liquid-tightly sealing the gaps between the openings 107m1 to 107m3 and the ceramic heaters 171 to 173. Furthermore, since the front end cap 107 including the inlet 103 is embedded in the fixed member 180, a part of the inlet 103, and therefore a part of the flow path 103i (on the body 101 side) penetrates the fixed member 180 from the outside to form a through-port 180p.

[0030] In this way, the unheated liquid W passes through the flow path 103i in the through-hole 180p, thereby cooling the fixing member 180. Therefore, by adopting a structure in which heating is performed only on the outer surface of the ceramic heater without passing the liquid through the inner hole, even if the heating temperature of the heater becomes high, overheating of the fixing member 180 around the ceramic heaters 171-173 is suppressed, which in turn suppresses thermal deformation of the container 100 (front end cap 107) in contact with the fixing member 180, and can suppress leakage of the liquid between the ceramic heater and the container.

[0031] Next, a liquid heating device 210 according to a second embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view taken from the same direction as Fig. 3. Components of the liquid heating device 210 that are the same as those of the liquid heating device 200 are given the same reference numerals, and descriptions thereof will be omitted. The liquid heating device 200 includes a container 110 and three ceramic heaters 171 to 173. The container 110 includes a body 111, a rear end lid 108 that closes an opening at one axial end of the body 111, and an inlet 113 and an outlet 105 for the liquid W.

[0032] Here, the body 111 has substantially the same triangular cylindrical shape (a cylindrical shape with a triangular cross section) as the body 101, but differs from the body 101 in that it does not have a front end cap 107 and that base ends 17T of the ceramic heaters 171-173 are embedded in a wall 111w on the other axial end side of the body 111. Also, the introduction port 113 is formed integrally with the body 111. Body portion 111 can be manufactured by insert molding, for example, in which a resin material is filled around ceramic heaters 171-173. In this way, the wall 111w and the ceramic heaters 171 to 173 are in liquid-tight contact with each other without any gaps. The wall 111w serves as a side wall surrounding the internal space 110i of the container 110. The wall 111w is formed so as to bury not only the base ends 17R of the ceramic heaters 171-173 but also parts of the lead terminals 18 and the lead wires 15 and 16.

[0033] The shape of the inlet 113 is substantially the same as the inlet 103 of the first aspect of the embodiment. Specifically, the inlet 113 protrudes above the wall 111w so as to straddle the upper side of the substantially triangular wall 111w when viewed from the axial direction, with the tip facing the inlet side. The inlet 113 extends vertically from this tip to near the center of the wall 111w (the center surrounded by the three ceramic heaters 171 to 173), then bends along the axial direction, opens on the inner surface of the wall 111w, and faces the internal space 110i. In this way, a part of the flow path 103i of the inlet 113 (on the body 111 side) penetrates through the wall 111w from the outside to form a through-portion 111p.

[0034] As a result, the wall 111w is cooled as the unheated liquid W passes through the flow path 113i in the through-hole 111p. Therefore, by adopting a structure in which heating is performed only on the outer surface of the ceramic heater without passing the liquid through the inner hole, it is possible to suppress thermal deformation of the wall 111w around the ceramic heaters 171-173 and suppress leakage of the liquid between the ceramic heater and the container, even if the heating temperature of the heater becomes high.

[0035] In the example of FIG. 6, the body 111 is insert-molded around the ceramic heaters 171-173, and the wall 111w and the ceramic heaters 171-173 are liquid-tightly adhered (sealed) together without any gaps, but this is not limiting. For example, similarly to FIG. 3, openings through which the ceramic heaters 171 to 173 pass may be provided in the wall 111w, and the gaps between the ceramic heaters 171 to 173 and the openings may be liquid-tightly sealed and fixed with epoxy resin.

[0036] In the present invention, if the outer diameter of the ceramic heater is 5 mm or less, even if an inner hole is provided in the ceramic heater, the inner hole will have a small diameter, making it difficult to introduce liquid and making the ceramic heater prone to overheating, making the present invention more effective.

[0037] As shown in Figures 2, 3, and 6, in the present invention, there may be a plurality of ceramic heaters 171 to 173 that are spaced apart from each other and extend in the front-to-back direction L, and the flow path 103i may be formed between at least two ceramic heaters 172, 173 as viewed from the front-to-back direction L. In this way, it is possible to effectively cool the area between the two ceramic heaters 172 and 173 that sandwich the flow path 103i, where heat tends to accumulate.

[0038] In the present invention, the axis n direction of the end portion of the flow path 103i facing the internal space 100i may be along the front-rear direction L. This allows the liquid W to flow easily on the outer surfaces of the ceramic heaters 171-173 along the front-rear direction L in which the ceramic heaters 171-173 extend, thereby preventing the liquid W from accumulating near the flow paths 103i and reducing the cooling effect.

[0039] It goes without saying that the present invention is not limited to the above-described embodiments, but covers various modifications and equivalents that fall within the spirit and scope of the present invention. For example, the shapes of the liquid heating device, ceramic heater, inlet, and flow path are not limited. Examples of the fixing member include epoxy resin and glass. The entire container may also be made of a single member formed by integral molding or the like.

[0040] Also, for example, in FIG. 3, the base ends of all of the multiple (three) ceramic heaters 171 to 173 are arranged at one end (front end lid 107 side) of the container 100, but the base ends of one or more ceramic heaters may be arranged at each of both ends (front end lid 107 side and rear end lid 108 side) of the container 100. In this case, however, the position of the outlet for the liquid W is near the center of the container 100 in the axial direction.

[0041] In the case of a structure in which the body 111 is insert-molded around the ceramic heaters 171-173 as shown in Fig. 6, if the extending direction (front-rear direction) L of the ceramic heaters 171-173 differs from the extending direction of the introduction port 113 (they are perpendicular to each other in Fig. 6), it is difficult to remove the molded product from the insert mold. In this case, it may become necessary to use a complex slide mold, or molding may become difficult. Therefore, it is preferable in terms of manufacturing to align the extending direction of the introduction port 123 with the extending direction (front-rear direction) L of the ceramic heaters 171 to 173, as in the liquid heating device 220 of FIG.

[0042] Specifically, in the example of Figure 7, the body 121 of the container 120 has a triangular cylindrical shape (a cylindrical shape with a triangular cross section) that is approximately the same as the body 111, and is similar to the body 111 in that the base ends 17T of the ceramic heaters 171 to 173 are embedded in the wall 121w on one end side of the body 121 in the axial direction, but the inlet 123 is not formed integrally with the body 121. The internal spaces 120i are formed around the three ceramic heaters 171 to 173, respectively, and are spaced apart from one another. The wall 121w is provided with openings extending in the front-rear direction L so as to communicate with the inside of each internal space 120i. Furthermore, a cylindrical inlet 123 is fitted into this opening, and the gap between them is liquid-tightly sealed with epoxy resin.

[0043] Therefore, also in the example of FIG. 7, a part of the flow path 123i of the inlet 123 (the side fitted into the body portion 111) penetrates through the wall 121w from the outside to form a penetration portion 121p. This allows the liquid W before heating to pass through the flow path 123i in the through portion 121p, thereby cooling the wall 121w. 7, the opening for fitting the inlet 123 has a hexagonal cross section, and the cross section of each internal space 120i is an ellipse that approaches the center (axis) of the body 121. This makes it easier for the outer portion of the opening to overlap with the inner portion of each internal space 120i. The overlapping portions then communicate with each other, allowing the liquid W to flow from the inlet 123 toward each internal space 120i. 7, the body 121 and the inlet 123 are formed as separate bodies, but they may be formed as a single body. [Example]

[0044] Alumina powder and glass component powder, which serves as a sintering aid, were ground and mixed with water in a mill, and a binder was added to obtain a clay-like mixture. Using an extruder, this mixture was extruded from a die equipped with a core to produce a cylindrical ceramic substrate, which was then cut to a predetermined length and calcined. On the other hand, a heating element pattern was formed on an alumina green sheet using tungsten and molybdenum paste, and furthermore, a terminal portion connected to this pattern and connected to the opposite surface of the sheet was printed and formed.

[0045] The printed ceramic green sheet was wrapped around a pre-fired ceramic substrate and fired together. The exposed terminals of the fired ceramic heater were Ni-plated, and Ni lead members were brazed to the ceramic heater with Ag solder to obtain a leaded ceramic heater. The ceramic heater was then inserted from the tip side into the opening of the front end lid 107 (FIG. 2) of the resin container, and epoxy adhesive was filled to cover the front end lid 107, including the space between the heater and the opening, to create an airtight seal. As described above, a ceramic heater with a total length of 60 mm, a heat generating length of 30 mm, an outer diameter of 2.8 mm, and a room temperature resistance of 9 Ω was installed, and the liquid heating device shown in FIGS. 1 to 3 was manufactured.

[0046] Water with a flow rate of 450 cc / min and a temperature of 5°C was flowed into the inlet of the obtained liquid heating device, and the applied voltage per heater was controlled so that the temperature of the hot water coming out of the outlet was 35°C.A continuous water flow test was conducted in which a cycle of 15 seconds of heater application and 15 seconds of stop was repeated 10 times. As a result, hot water was produced without any problems during the continuous water flow test, and no thermal deformation was observed in the front end cover 107 near the epoxy adhesive that forms the fixed portion after the test, and no water leakage was observed. In addition, the heat resistance temperature of the epoxy adhesive that forms the fixing part is usually higher than the heat resistance temperature of the resin of the container (front end lid 107), and even if the epoxy adhesive is heated by the heater, there is little significant thermal deformation, but heat is transferred from the epoxy adhesive to the front end lid 107, causing thermal deformation of the front end lid 107. [Explanation of symbols]

[0047] 17a Heat generating part 17T Ceramic heater tip 17R Ceramic heater base end 100, 110, 120 containers 100i, 110i, 120i interior space 103i, 113i, 123i flow path 107m1~107m3 Container opening 111W, 121W wall 171~173 Ceramic heater 180 Fixing member 200, 210, 220 liquid heating equipment L Forward / backward direction W Liquid (water) n The axis of the end of the flow path facing the internal space

Claims

1. a container enclosing an interior space and having an opening; a ceramic heater extending in a front-rear direction and passing through the opening, with a tip end located within the internal space and a base end located outside the internal space, the ceramic heater having a heat generating portion at the tip end; a fixing member that fixes the ceramic heater to the container while sealing a gap between the opening and the ceramic heater; Equipped with A liquid heating device that heats a liquid in the internal space by the ceramic heater, the container further includes a front end lid separate from the fixing portion, the front end lid closing the opening, the front end lid through which the base end of the ceramic heater passes and which has a flow path; the fixing portion covers at least a portion of the flow path of the front end cap, A liquid heating device, characterized in that the liquid is introduced into the internal space through the flow path.

2. a container having a wall surrounding an interior space; a ceramic heater extending in a front-rear direction and penetrating the wall, with a tip end located within the internal space and a base end located outside the internal space, the ceramic heater having a heat generating portion at the tip end; Equipped with A liquid heating device that heats a liquid in the internal space by the ceramic heater, The ceramic heater is fixed to the wall, a wall through which the ceramic heater is fixed, the wall having a flow path formed therethrough so as to overlap a region of the fixed portion of the ceramic heater along the front-rear direction; A liquid heating device, characterized in that the liquid is introduced into the internal space from the outside through the flow path.

3. 3. The liquid heating device according to claim 2, wherein the wall and the ceramic heater are in close contact with each other without any gap therebetween.

4. 4. The liquid heating device according to claim 1, wherein the ceramic heater has an outer diameter of 5 mm or less.

5. a plurality of the ceramic heaters extending in the front-rear direction and spaced apart from each other; 5. The liquid heating device according to claim 1, wherein the flow path is formed between at least two ceramic heaters when viewed from the front-to-rear direction.

6. 6. The liquid heating device according to claim 5, wherein an axial direction of an end portion of the flow path facing the internal space is along the front-rear direction.

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