201242561 六、發明說明： 【明戶斤々焉】 發明領域 本發明係有關於一種衛生洗淨裝置，特別是有關於一 種具有可喷出溫水之噴嘴的衛生洗淨骏置。 C j 發明背景 以往，已知有由喷嘴喷出溫水之衛生洗淨裝置。 例如，平板狀之加熱器縱向放置收納於厚度尺寸較小 之立方體形狀之殼體内。沿著平板狀加熱器之兩傳熱面之 各個形成有朝水平方向蛇行且朝向上方之2個流路。在驅 動該平板狀加熱器期間，洗淨水會沿著各流路而流通，昇 溫到適當溫度（例如，參考專利文獻1)β 先行技術文獻 專利文獻 【專利文獻1】日本專利公開公報特開平1〇_22〇876號 公報 t ^^明内3 發明概要 發明欲解決之課題 為知例中’在蛇行之流路中，可能會產生洗淨水滞留 並且氣、泡停滯之部分。在如此洗淨水滞留之部分中，洗淨 水會局料騰。該局部舞部分巾，洗淨賴含之釣成分 等會固定附著於平板狀加熱器之表面，生成水垢。因水垢 201242561 而往洗淨水之熱傳達受到阻礙，招致平板狀加熱器之局部 的高溫化。進而，助長水垢的生成，且因堆積之水垢而洗 淨水之流路阻力變高。因此，可能變得無法確保必要之洗 淨水的流量。 又，氣泡停滯之部分中，會招致洗淨水之滯留及平板 狀加熱器之局部的高溫化等，而產生上述之問題。 進而，當因為水垢而平板狀加熱器局部成為高溫時， 平板狀加熱器會產生溫度差。因為該溫度差造成之熱應 力，將陶瓷使用於發熱體之平板狀加熱器中，平板狀加熱 器會產生龜裂或破裂等，平板狀加熱器會故障。 本發明係為了解決如此課題而作成者，其目的在於提 供一種確保必要之洗淨水的流量，且可防止故障之衛生洗 淨裝置。 解決課題之方法 本發明之態樣之衛生洗淨裝置具有：喷嘴、具可連接 於供水源之上游端，並且下游端連接於前述喷嘴之供水 路、及設置於前述供水路之熱交換器，前述熱交換器具有： 殼體，包含：流入部；位於前述流入部較上方之流出部； 及板狀之加熱器收容空間，係形成為下端部連通於前述流 入部，上端部連通於前述流出部，且朝上下方向延伸；平 板狀加熱器，收容於前述殼體之加熱器收容空間，且朝上 下方向延伸，並且包含與前述加熱器收容空間之主面相對 向之傳熱面；流路空間，係形成於前述傳熱面與前述加熱 器收容空間之主面之間的間隙，前述流路空間形成為前述 201242561 流入部側之前述間隙的寬度比前述流出部側之前述間隙的 寬度小。 發明效果 本發明具有以上所說明之構成，並達到可提供可確保 必要之洗淨水的流量且防止故障之衛生洗淨裝置的效果。 本發明之上述目的、其他目的、特徵、及優點在參考 添附圖式之下，可由以下之較佳實施態樣之詳細說明而清 楚明瞭。 圖式簡單說明 第1圖係顯示本發明之實施形態2之衛生洗淨裝置裝 a又於便器之狀態的立體圖。 第2圖係顯示裝載於第1圖之衛生洗淨裝置之熱交換 器之正面的平面圖。 第3圖係顯不第2圖之熱交換器之右側主面的平面圖。 第4圖係顯示沿著第2圖之A-A線而切斷之熱交換器 的橫截面圖。 第5圖係顯示沿著第3圖之B-B線而切斷之熱交換器 的縱戴面圖。 第6圖係第4圖之C之領域之放大圖。 第7圖係顯示形成於第4圖之熱交換器之電熱線的平 面圖。 $ 8圖係顯示形成於第4圖之熱交換器之電熱線之變 形例的平面圖。 $ 9圖係顯不本翻之實施形態1之衛生洗淨裝置之 201242561 主要構成的模式圖。 第10圖係顯示裝載於第9圖之衛生洗淨裝置之熱交換 器的橫截面圖。 第11圖係顯示本發明之變形例之衛生洗淨裝置之主要 構成的模式圖。 【實桃·方式】 較佳實施例之詳細說明 (為本發明之基礎之知識） 本發明人們就沿著平板狀加熱器之兩傳熱面形成流路 之熱交換器進行了檢討。 般而§，係以兩傳熱面側對洗淨水之各自的傳熱量 大約相同為前提來設計熱交換器。假設於兩側之傳熱量產 生大的差異時，在其中一側之流路中會產生局部的沸騰現 象了月b會產生氣泡。因為此種氣泡，流路中之洗淨水之 流通阻力會變高，兩流路之流量會不平衡，傳熱量之差變 得更大。 又，也有在熱交換器之出水口附近設置熱阻器等之溫 度感測器。此種情況下，當氣泡大量成長，附著於溫度感 測器時，溫度感測器無法接觸到洗淨水。因此，溫度感測 器會變得無法適當地進行檢測。 進而’當氣泡附著於傳熱面且大量成長時，氣泡會介 於傳熱面與洗淨水之間，使兩者分離。此種情況下，熱由 傳‘、，、面在洗淨水傳達變得困難，傳熱面之溫度會大幅上 昇。而附著有氣泡之傳熱面'與該相反之傳熱面的溫度差 201242561 會變大。由於該熱應力，平板狀加熱器會產生變形等，熱 交換器之壽命變短。 水垢附著於傳熱面之控制的主要因素係傳熱面的溫 度。一般而言’為了抑制水垢的附著，傳熱面之設定溫度 疋為產生沸騰之100¾以下、且宜為8〇〇c以下。又，傳熱 面之設定溫度亦可依據自來水之水垢濃度或加熱器之所需 而子久時間等而適當決定。傳熱面之一部份也超過設定溫度 時’该部分會附著水垢，水垢成為傳熱障礙。為了避免此 一問題，只要增加傳熱面之面積即可。可是，這成為熱交 換器之成本增加因此不佳。又，也考慮將平板狀加熱器之 瓦特密度或傳熱係數之分布設定成傳熱面之溫度整體是大 致均一的。此種情況下，傳熱面之尺寸可為最小，且令傳 熱面之溫度在設定溫度以下，但平板狀加熱器之成本變高。 又，也考慮要抑制水垢等原因造成氣泡的發生，並促 使氣泡排出，因此更加大洗淨水之速度。此種情況下，可 提高由傳熱面往洗淨水之傳熱係數，縮小傳熱面之尺寸。 然而，一般而言，使用於溫水洗淨便座之衛生洗淨裝置中， 洗淨水之一次使用水量較少。因此流路之厚度必須做成非 常薄，且提咼洗淨水之流速。通常，洗淨水之流量的最大 値為50〇CC/min左右。對於該流量値，為了更為提高流速， 必須將流路厚度設定在〇_5mm以内。如此，當流路厚度非 常薄時’容易產生局部之流速的不均一性。該流路厚度： 0.5mm比速度邊界層之厚度：數mm之集管部小，因此速 度邊界層覆蓋流路全域。因此，速度梯度因流路厚度而產 201242561 生變化，容易因為流路厚度之不均一而產生流速之不均一。 又，速度邊界層係在傳熱面之速度為零，速度會急速 變化之流體層。因此，使傳熱面上之泡由傳熱面上排出之 力較弱。又，當流路厚度較薄時，流路中產生之泡的大小 容易變得比流路厚度大。此種情況下，泡會對應於流路厚 度而變形，並且因為泡之表面張力而產生上推力，故泡變 得難以移動。因此，泡滯留於流路中，因為該泡而流速產 生局部的不均一。 當產生該局部的流速不均一時，如瓦特密度為30W/ cm2以上之高瓦特密度之平板狀加熱器中，傳熱面溫度會局 部大幅度的上昇。在該處產生沸騰，進而產生泡。因此， 助長流動之不均一，傳熱面會燒毁。 由於壓力損失增加，因此難以大幅地加大洗淨水之流 速。又，由於速度不均一，因此也難以使流路厚度較薄。 進而，使流路朝水平方向蛇行時，在流路流動之洗淨水的 距離及時間較長，且流路截面積較小，因此因為氣泡而洗 淨水之流動容易停滯。是故，蛇行之流路也不佳。 將平板型之加熱器使用於熱交換器時，熱交換器會變 的較為精簡，又，容易加大傳熱面積。可是，因為強制對 流而難以生成沿著傳熱面均一且快速之流動。又，由於生 成沿著傳熱面之快速的流動，因此如上述，當減薄流路之 厚度時，流動容易變得不均一。因此，當產生部分過熱部 時，熱會集中於該過熱部，該部分之洗淨水會蒸發，產生 氣泡。若氣泡不流出，該部分會更為加熱。因此，當氣泡 8 201242561 變大，傳熱面變得極度高溫時，會破壞加熱器。 又，由於形成沿著傳熱面之較薄且快之流動，因此也 考慮於流路之流入部設置扁平之節流部。可是，空氣等容 易貯存於節流部，該氣泡之流動會不均一。如此，亦有於 流路之流入部設置扁平之節流部的課題。 進而，家庭之自來水配管中，也於流體中含有空氣。 因此，必須使空氣等之氣泡不存留於熱交換器内而可順利 排出。 本發明係根據上述見解而做成者。 本發明之實施形態之衛生洗淨裝置具有：喷嘴、具可 連接於供水源之上游端，並且下游端連接於前述喷嘴之供 水路、及設置於前述供水路之熱交換器，前述熱交換器具 有：殼體，包含：流入部；位於前述流入部較上方之流出 部；及板狀之加熱器收容空間，係形成為下端部連通於前 述流入部，上端部連通於前述流出部，且朝上下方向延伸； 平板狀加熱器，收容於前述殼體之加熱器收容空間，且朝 上下方向延伸，並且包含與前述加熱器收容空間之主面相 對向之傳熱面；流路空間，係形成於前述傳熱面與前述加 熱器收容空間之主面之間的間隙，前述流路空間形成為前 述流入部側之前述間隙的寬度比前述流出部側之前述間隙 的寬度小。 衛生洗淨裝置中，前述平板狀加熱器係亦可構成為前 述流入部側之發熱密度比前述流出部側之發熱密度大。 衛生洗淨裝置中，前述平板狀加熱器具有陶瓷基體、 201242561201242561 VI. INSTRUCTION DESCRIPTION: FIELD OF THE INVENTION The present invention relates to a sanitary washing device, and more particularly to a sanitary washing device having a nozzle capable of spraying warm water. C j BACKGROUND OF THE INVENTION Conventionally, there has been known a sanitary washing device that ejects warm water from a nozzle. For example, a flat heater is placed longitudinally in a cubic shaped housing having a small thickness. Two flow paths that are meandering in the horizontal direction and facing upward are formed along each of the two heat transfer surfaces of the flat heater. During the driving of the flat heater, the washing water flows along the respective flow paths and is heated to an appropriate temperature (for example, refer to Patent Document 1). PRIOR ART DOCUMENT Patent Document [Patent Document 1] Japanese Patent Laid-Open No. 1〇_22〇876号 t ^^明内 3 SUMMARY OF THE INVENTION The object to be solved by the invention is that in the case of the meandering flow, there may be a part in which the washing water is retained and the gas and bubbles are stagnant. In such a part of the water retention, the washing water will be rushed. The partial dance portion of the towel, which is washed and contained, is fixedly attached to the surface of the flat heater to generate scale. Due to the scale 201242561, the heat transfer to the washing water is hindered, resulting in a localization of the flat heater. Further, the generation of scale is promoted, and the flow path resistance of the washed water is increased due to the accumulated scale. Therefore, it may become impossible to ensure the flow of necessary washing water. Further, in the portion where the bubble is stagnant, the retention of the washing water and the high temperature of the portion of the flat heater are caused, and the above problems occur. Further, when the flat heater is locally heated due to scale, the flat heater generates a temperature difference. Because of the thermal stress caused by the temperature difference, the ceramic is used in the flat heater of the heating element, and the flat heater causes cracks or cracks, and the flat heater may malfunction. The present invention has been made to solve such problems, and an object of the present invention is to provide a sanitary washing apparatus capable of preventing a flow rate of necessary washing water and preventing malfunction. Solution to Problem A sanitary washing apparatus according to an aspect of the present invention includes a nozzle, a water supply path that is connectable to an upstream end of a water supply source, a downstream end connected to the nozzle, and a heat exchanger disposed in the water supply path. The heat exchanger has a casing including: an inflow portion; an outflow portion located above the inflow portion; and a plate-shaped heater housing space formed such that a lower end portion communicates with the inflow portion, and an upper end portion communicates with the outflow portion And extending in a vertical direction; the flat heater is housed in the heater accommodating space of the casing and extends in the vertical direction, and includes a heat transfer surface facing the main surface of the heater accommodating space; a space formed in a gap between the heat transfer surface and a main surface of the heater accommodating space, wherein the flow path space is formed such that a width of the gap on the inflow portion side of the 201242561 is smaller than a width of the gap on the outflow portion side . Advantageous Effects of Invention The present invention has the above-described configuration, and achieves an effect of providing a sanitary washing device capable of ensuring a flow rate of necessary washing water and preventing malfunction. The above and other objects, features, and advantages of the present invention will be apparent from BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a state in which a sanitary washing device according to a second embodiment of the present invention is installed in a toilet. Fig. 2 is a plan view showing the front surface of the heat exchanger mounted in the sanitary washing apparatus of Fig. 1. Fig. 3 is a plan view showing the right main surface of the heat exchanger of Fig. 2; Fig. 4 is a cross-sectional view showing the heat exchanger cut along the line A-A of Fig. 2; Fig. 5 is a longitudinal cross-sectional view showing the heat exchanger cut along the line B-B of Fig. 3. Fig. 6 is an enlarged view of the field of Fig. 4C. Fig. 7 is a plan view showing a heating wire formed in the heat exchanger of Fig. 4. The Fig. 8 is a plan view showing a modification of the electric heating wire formed in the heat exchanger of Fig. 4. The $9 figure shows a schematic diagram of the main components of the sanitary cleaning device of the first embodiment. Fig. 10 is a cross-sectional view showing the heat exchanger mounted in the sanitary washing device of Fig. 9. Fig. 11 is a schematic view showing the main configuration of a sanitary washing device according to a modification of the present invention. [Solid Peach Method] Detailed Description of Preferred Embodiments (Knowledge of the Basics of the Invention) The inventors of the present invention reviewed a heat exchanger that forms a flow path along the two heat transfer surfaces of a flat heater. As a general rule, the heat exchanger is designed on the premise that the heat transfer amount of each of the washing water is approximately the same on both heat transfer sides. Assuming that there is a large difference in the amount of heat transfer on both sides, a local boiling occurs in one of the flow paths, and a bubble is generated in the month b. Because of such bubbles, the flow resistance of the washing water in the flow path becomes high, the flow rates of the two flow paths are unbalanced, and the difference in heat transfer amount becomes larger. Further, there is a temperature sensor in which a heat resistor or the like is provided in the vicinity of the water outlet of the heat exchanger. In this case, when the bubble grows in a large amount and adheres to the temperature sensor, the temperature sensor cannot come into contact with the washing water. Therefore, the temperature sensor may become undetectable. Further, when the bubble adheres to the heat transfer surface and is largely grown, the bubble is interposed between the heat transfer surface and the washing water to separate the two. In this case, it is difficult to convey the heat by the ‘,, and the surface, and the temperature of the heat transfer surface will rise sharply. The temperature difference between the heat transfer surface to which the bubble is attached and the opposite heat transfer surface will become larger 201242561. Due to this thermal stress, the flat heater is deformed and the like, and the life of the heat exchanger is shortened. The main factor controlling the adhesion of scale to the heat transfer surface is the temperature of the heat transfer surface. In general, in order to suppress the adhesion of scale, the set temperature 传热 of the heat transfer surface is 1003⁄4 or less, and preferably 8 〇〇c or less. Further, the set temperature of the heat transfer surface can be appropriately determined depending on the scale concentration of the tap water, the required time of the heater, and the like. When one part of the heat transfer surface also exceeds the set temperature, the scale will adhere to the scale, and the scale becomes a heat transfer barrier. In order to avoid this problem, it is only necessary to increase the area of the heat transfer surface. However, this increases the cost of the heat exchanger and is therefore not good. Further, it is also considered that the distribution of the wattage density or the heat transfer coefficient of the flat heater is set such that the temperature of the heat transfer surface as a whole is substantially uniform. In this case, the size of the heat transfer surface can be minimized, and the temperature of the heat transfer surface is set below the set temperature, but the cost of the flat heater becomes high. Further, it is also considered to suppress the occurrence of bubbles due to scale and the like, and to promote the discharge of the bubbles, thereby increasing the speed of washing water. In this case, the heat transfer coefficient from the heat transfer surface to the washing water can be increased, and the size of the heat transfer surface can be reduced. However, in general, in a sanitary washing device for washing a toilet seat with warm water, the amount of water used for the washing water is small. Therefore, the thickness of the flow path must be made very thin and the flow rate of the washing water can be raised. Usually, the maximum flow rate of the washing water is about 50 〇CC/min. For this flow rate, in order to increase the flow rate, the flow path thickness must be set within 〇_5 mm. Thus, when the thickness of the flow path is very thin, it is easy to cause local flow rate inhomogeneity. The thickness of the flow path: 0.5 mm is greater than the thickness of the boundary layer of the velocity: the header portion of several mm is small, so the velocity boundary layer covers the entire flow path. Therefore, the velocity gradient is changed due to the thickness of the flow path. It is easy to produce a non-uniform flow rate due to the uneven thickness of the flow path. Further, the velocity boundary layer is a fluid layer whose velocity on the heat transfer surface is zero and the velocity rapidly changes. Therefore, the force of discharging the bubbles on the heat transfer surface from the heat transfer surface is weak. Further, when the thickness of the flow path is thin, the size of the bubble generated in the flow path tends to be larger than the thickness of the flow path. In this case, the bubble is deformed in accordance with the thickness of the flow path, and the upper thrust is generated due to the surface tension of the bubble, so that the bubble becomes difficult to move. Therefore, the bubble stays in the flow path because the flow rate causes local unevenness. When the local flow velocity is not uniform, such as a flat heater having a high wattage density of 30 W/cm2 or more, the temperature of the heat transfer surface is greatly increased. At this point, boiling occurs, which in turn produces bubbles. Therefore, it encourages uneven flow and the heat transfer surface will burn out. Since the pressure loss increases, it is difficult to greatly increase the flow rate of the washing water. Moreover, since the speed is not uniform, it is also difficult to make the thickness of the flow path thin. Further, when the flow path is meandered in the horizontal direction, the distance and time of the washing water flowing through the flow path are long, and the flow path cross-sectional area is small. Therefore, the flow of the washing water is likely to be stagnant due to the air bubbles. Therefore, the path of the snake line is not good. When a flat type heater is used in a heat exchanger, the heat exchanger becomes more compact, and the heat transfer area is easily increased. However, it is difficult to generate a uniform and rapid flow along the heat transfer surface because of forced convection. Further, since the rapid flow along the heat transfer surface is generated, as described above, when the thickness of the flow path is reduced, the flow tends to become uneven. Therefore, when a partial superheating portion is generated, heat is concentrated on the superheated portion, and the portion of the washing water evaporates to generate bubbles. If the bubble does not flow out, the part will be heated more. Therefore, when the bubble 8 201242561 becomes large and the heat transfer surface becomes extremely hot, the heater is destroyed. Further, since a relatively thin and fast flow along the heat transfer surface is formed, it is also considered that a flat throttle portion is provided in the inflow portion of the flow path. However, air or the like is easily stored in the throttle portion, and the flow of the bubbles may be uneven. In this way, there is also a problem in that a flat throttle portion is provided in the inflow portion of the flow path. Further, in the tap water pipe of the household, air is also contained in the fluid. Therefore, it is necessary to allow air bubbles such as air to be discharged without being left in the heat exchanger. The present invention has been made based on the above findings. A sanitary washing apparatus according to an embodiment of the present invention includes: a nozzle, a water supply path connected to an upstream end of the water supply source, a downstream end connected to the nozzle, and a heat exchanger provided in the water supply path, the heat exchanger The housing includes: an inflow portion; an outflow portion located above the inflow portion; and a plate-shaped heater housing space formed such that a lower end portion communicates with the inflow portion, and an upper end portion communicates with the outflow portion, and The flat heater extends in the heater accommodating space of the casing and extends in the vertical direction, and includes a heat transfer surface facing the main surface of the heater accommodating space; the flow path space is formed In the gap between the heat transfer surface and the main surface of the heater accommodating space, the flow path space is formed such that the width of the gap on the inflow portion side is smaller than the width of the gap on the outflow portion side. In the sanitary washing apparatus, the flat heater may be configured such that the heat generation density on the side of the inflow portion is larger than the heat generation density on the side of the outflow portion. In the sanitary washing device, the aforementioned flat heater has a ceramic base, 201242561
衛生洗淨裝置中，亦 置中’亦可為;t述平板狀加熱器具有陶曼In the sanitary washing device, it can also be placed in the middle;
具有主流路、及由前述主流路朝向前 俠态更具有入水口、形 之集管部，前述集管部 前述流入部漸漸變狹小 之節流流路。 以下、參考圖式並說明本發明之實施形態。 再者’以下透過全部圖式’相同或者相當之要件則賦 予相同參考標號，並省略其重複之說明。 又’針對將熱交換器10縱向放置成使平板狀加熱器2〇 之傳熱面20a、20b為錯直方向之狀態加以說明。各圖式所 示之Z方向係表示鉛直方向。X方向係表示與鉛直方向直 交且平行於平板狀加熱器20之傳熱面2〇a、2〇b的方向。γ 方向係表示與Z方向及X方向之任一者直交的方向。進 而，截面積係表示與洗淨水之流動直交之平面的面積。 (實施形態1) 第9圖係顯示實施形態1之衛生洗淨裝置i之主要構 成的模式圖。 衛生洗淨裝置1具有：喷嘴7;具有可連接於供水源8 10 201242561 之上游端並且下游端連接於喷嘴7之供水路9;及設置於供 水路9之熱交換器1〇。 第圖係顯示裝載於第9圖之衛生洗淨裝置1之熱交 換益10的橫戴面圖。 熱父換器10具有：殼體23，包含流入部i〇a ;位於流 入部l〇a較上方之流出部10b;下端部連通於流入部1〇a 且上端部連通於流出部1 〇b且朝上下方向延伸而形成之板 狀加熱器收谷空間23c者；平板狀加熱器2〇，朝上下方向 延伸地收谷於殼體23之加熱器收容空間23c，且包含與加 熱器收谷空間23c之主面3〇a、40a相對向之傳熱面20a、 20b，及形成於傳熱面2〇a、2〇b與加熱器收容空間23c之 主面30a、40a之間之間隙的流路空間25。流路空間25形 成為流入部10a側之間隙的寬度比流出部丨〇b側之間隙的 寬度小。在此’所謂「上下方向」係包含鉛直方向及與鉛 直方向交叉之方向双者的概念。「加熱器收容空間」係意咮 當假設自殼體除去加熱器之情況下，包含存在有加熱器之 領域及與該領域連接之空間的空間。「流路空間」可換〆種 說法為形Ml殼_沿著平板狀加熱器之__對傳熱面而 導入流體（在此為水）之流路。 上述構成之衛生洗淨裝置i中，洗淨水由供水源8流 經供水路9。洗淨水在供水路9巾流人熱交換^ 1()，旅在 此被加熱。成為高溫之洗淨水由熱交換器1G流出，而往嘴 嘴7供給。藉此，溫水自噴嘴7噴出。 又’熱父換益10中，洗淨水由流入部l〇a流入殼體23 201242561 之加熱器收容空間23c。洗淨水進入加熱器收容空間23c 之平面狀主面3〇a、4〇a與平板狀加熱器2〇之傳熱面2〇a、 20b之間’並通過流路空間25。此時，洗淨水被傳熱面2〇a、 20b加熱，其溫度上昇。 該流路空間25中’流入部10a側之間隙的寬度比流出 部10b側之間隙的寬度小。因此，在流路空間25流動之洗 淨水在流入部10a側的強制對流會變快。在此，由傳熱面 20a、20b與洗淨水之邊界層的速度梯度變大，傳熱係數變 高。由傳熱面20a、20b傳熱到洗淨水，傳熱面2〇a、20b 之溫度較低，可防止水垢附著於傳熱面20a、20b。 洗淨水藉由強制對流而由流入部1 〇a側流往流出部 10b側。在流出部10b側中，洗淨水在傳熱面20a、20b更 被加熱。藉此，混•入至洗淨水之空氣會膨脹，產生氣泡。 由於該流出部l〇b側之間隙的寬度較大，氣泡不會停留於 流路空間25而往流出部l〇b流出。 又，藉由洗淨水之溫度上昇，其密度變小’產生自然 對流之上昇流’洗淨水流往流出部10b。由於該流出部10b 侧之隙間的寬度較大’因此藉由自然對流之上昇流’氣泡 容易被排除，且提高由傳熱面20a、20b往洗淨水之傳熱係 數。 根據上述構成之衛生洗淨裝置1，藉由氣泡順利地排 出，不會因為氣泡而阻礙洗淨水與傳熱面20a、20b之熱交 換，可安定的進行。 又，藉由氣泡，洗淨水之一部份滯留’降低水垢在局 12 201242561 部產生。因此，水垢不會縮小流路空間25，洗淨水可順利 地流動，因此可確保必要流量之洗淨水。 進而，氣泡不附著於傳熱面20a、20b，可防止該部分 變高溫，而在傳熱面20a、20b產生溫度差。藉此，不會因 為溫度差造成之熱應力而使傳熱面20a、20b變形且損壞， 可防止平板狀加熱器20故障。 (實施形態2) 〔衛生洗淨裝置之構成〕 第1圖係顯示將實施形態2之衛生洗淨裝置1裝設於 便器2之廁所。 衛生洗淨裝置1配設於便器2之上面。衛生洗淨裝置1 具有本體部3、便器座部4、便器蓋部5、及操作部6。 本體部3係配設於便器座部4之後側、也就是由就座 之使用者來看係配設於背後側。本體部3為橫長之筐體 3a，且收容有第9圖所示之供水路9及熱交換器10。又， 除此之外，本體部3也收納有未圖示之洗淨單元、乾燥單 元、及用以控制該等動作之控制單元等。 供水路9由附設於便器2之設置物之自來水設備（供 水源8)經由熱交換器10將自來水（流體、液體、洗淨水） 導入至噴嘴7。當使用者操作操作部6且進行預定之輸入 時，驅動洗淨單元。洗淨水在熱交換器10加溫，而溫水由 喷嘴7呈喷水狀朝便器2之開口吐出。 〔熱交換器之構成〕 第2圖係顯示熱交換器10之正面的平面圖。第3圖係 13 201242561 顯示熱交換器1G之右側主面的平面圖。第㈣係顯示 第2圖之Α·Α線而切斷之熱交換器的橫截面圖 圖係顯示沿著第3圖之Β_β線而_之熱交換器1〇 面圖。第6圖係第4圖之c領域的放大圖。 截 熱交換器10在Y方向的厚度尺寸較小，於心 構成長方形。如第4圖所；问 圓所不，熱交換器10具有平板狀加埶 器20與第一流路形成構件21與第二流路形成構件U。…、 藉由第-流路形成構件21及第二流路形成構件 成殼體23 °第一流路形成構件η及第二流路形成構件22 係由例如分別將玻璃纖維複合成ABs樹脂之強化A 脂所形成。 & 第一流路職構件21崎於平板狀加熱ϋ 20之第— 傳熱面20a側。第—流路形成構件21包含基座部％及階 形棚部31。基座部30包含基座面（主面）30a，基座面3二 為平面形狀且與第—傳熱面2〇a相對向。在階形棚部31 中’基座部30之Y方向的厚度會改變。從階形棚部η到 流出部⑽側之基座部30的厚度比從階形棚部31到流入 部10a側小。因此，從階形棚部31到流入部⑽側之基座 面30a相較於流出部側之基座φ施#近第_傳熱面 20a。流入部10M則之基座面3〇a與第一傳熱面2〇&之間的 寬度比流出部1%侧之基座面3〇a與第-傳熱面2〇a之間 的寬度狹小。 第-流路形成構件21於基座部％之躲部含括全周 設有壁狀之凸緣部32。於凸緣部32之前端部形成卡合溝 14 201242561 33且卡σ /冓33沿著凸緣部32含括其全周而形成。 第二流路形成構件22配置於平板狀加熱器20之第二 傳熱面20b側。第二流路形成構件包含基座#仙及階 形棚部41。基座部40包含基座© (主面）40a，基座面40a 為平面形狀且與第二傳熱面毫相對向。階形棚部W中， 基座部40之Y方向的厚度改變。從階形棚部μ到流出部 l〇b側之基座# 4〇的厚度比從階形棚部41到流入部伽 側小。因此’從階形棚部41到流入部側之基座面術相較 於机出4 10b侧之基座面4〇a，接近第二傳熱面勘。流入 部10a側之基座面4〇a與第二傳熱面2〇b之間的寬度比流 tIMOb側之基座自恤與第二傳熱面2⑽之間的寬度狹 ^ ㈣構件22於基座部40之周緣部含括全周 =壁狀之凸緣部42。凸緣部&朝基座面伽之相反側突 端邻=凸緣部42之前端部於基座面_側折返。於該前 W設置卡合突起 42之全周而形成。 3括凸緣淖 第二流路形成構件22之凸緣 構件21之凸綾畔适八第机路形成 突起43 \ ’且帛二祕形錢件22之卡合 合突起路形成構件21之卡合溝33。例如，卡 超a波熔接而固定於卡合溝33。藉此，第一 λ瓜形成構件21與第二流路#彡 成殼體23。 Μ成構件22密封地接合，形 毅體23具有個側面、⑽主面、頂面及底面’且 15 201242561 包含被該等所包圍之略矩形之中空部。該略矩形之中空部 構成板狀之加熱器收容空間23C。加熱器收容空間23c朝上 下方向延伸。加熱器收容空間23c之下端部連通於流入部 10a’且上端部連通於流出部10b<jY_z方向之2個側面中， 於其中1個側面，入水口 23a及出水口 23b開口。出水口 23b之開口成為流出部l〇b。入水口 23a設置於側面之一端 下部，連接於供水路9 (第9圖）之上游側端部。出水口 23b s史置於側面之一端上部，且連接於供水路9 (第9圖） 之下游側端部。X-Z方向之2個主面分別由基座面3〇a、4〇a 所形成。頂面與平板狀加熱器2〇之上端相對向。頂面傾斜 成愈接近出水口 23b，頂面與平板狀加熱器2〇之上端的間 隙愈寬。底面與平板狀加熱器2〇之下端相對向。流路空間 25之流入部l〇a於頂面開口，流入部1〇a朝χ方向延伸。 於殼體23之内部形成流路空間25及集管部45。 流路空間25包含第一傳熱面20a與基座面30a之間之 "il路、及第二傳熱面2〇b與基座面40a之間之流路。該等2 個流路係呈對稱形成於平板狀加熱器20之兩側。2個流路 分別具有入口側流路25a及出口側流路25b。入口側流路 25a設置於靠近較階形棚部31 ' 41下部之入水口 23a側。 出口側流路25b設置於靠近較階形棚部31、41上部之出水 口 23b側。入口側流路25a中之γ軸方向的厚度較出口側 流路25b中之γ軸方向的厚度小。 集官部45係如第6圖所示’設置於流路空間25之流 入部10a與入水口 23a之間，且朝χ方向延伸。集管部45 16 201242561 包含集官部主流路45a及集管部節流流路45b。集管部主流 路45a中之X-Y方向之流路截面積較集管部節流流路顿 廣。也就是說，該X-Y方向之流路截面積係相對於由人水 口 23a流往流入部i〇a之洗淨水的流動直交。集管部節流 流路45b之流路截面積係由集管部主流路且由流入部 l〇a朝向流入部l〇a而漸漸變狹窄。集管部節流流路4北 具有曲柄形狀。集管部節流流路45b包含垂直部45bb、水 平部45bc及垂直部45bd。其截面積依照垂直部45bb、水 平部45bc及垂直部45bd之順序而變小（即變狹窄）。 平板狀加熱器20收容於殼體23之加熱器收容空間 23c’且朝上下方向延伸。平板狀加熱器2〇具有矩形平板 狀，且於兩面包含第一及第二傳熱面2〇a、2〇b。平板狀加 熱器20包含陶瓷基體20k、電阻體圖案2〇p及電極（未圖 示）。防止傳熱面20a、20b之溫度在局部比預定溫度還高。 該預定溫度一般而言係將傳熱面2〇3、2%之溫度設定在產 生沸騰之100。(：以下，且宜為80。(：以下。進而，預定溫度 可由自來水之水垢濃度、或加熱器之所需耐久時間等而適 當決定之。 電阻體圖案20p於陶瓷基體20k上印刷有電阻體。電 阻體圖案20p構成電熱線（加熱線），並且藉由來自電極之 通電而發熱。如第7圖所示，加熱線朝χ方向長長地延伸， 且蛇行並朝ζ方向之上側擴展。入口側流路25a中之加熱 線之寬度20s比出口側流路25b中之加熱線之寬度2〇s細， 且該加熱線之截面積小。該加熱線之寬度2〇s較細，且加 17 201242561 熱線之截面積愈小，加熱線之電阻值愈大。因此，入口側 流路25a中之加熱線之電阻值比出口側流路25b中之加熱 線之電阻值高。藉此，入口側流路25a中之電阻體之圖案 20p之發熱密度比出口側流路25b中之電阻體之圖案20p 的發熱密度高。 〔衛生洗淨裝置中之洗淨水之流動〕 如第9圖所示，打開電磁閥時，洗淨水由供水源8之 自來水配管經由分岐水龍頭而流入供水路9。如第3圖及第 4圖所示，洗淨水由供水路9經由入水口 23a而流入殼體 23内。 如第4圖〜第6圖所示，洗淨水進入集管部45之集管 部主流路45a。集管部節流流路45b之截面積相較於集管部 主流路45a之截面積非常小，因此由集管部主流路45a往 集管部節流流路45b之阻力比往集管部主流路45a之X方 向之阻力大。因此，洗淨水大部分流往集管部主流路45a 之X方向，洗淨水一樣充滿集管部主流路45a。而且洗淨 水由集管部主流路45a流往集管部節流流路45b。該集管部 節流流路45b之流路截面積會漸漸變狹小，因此洗淨水之 流動會漸漸變快。又，集管部節流流路45b沒有空氣可滯 留之場所。因此，即使洗淨水中混入空氣，空氣也不會停 留而運往流入部10a側。當洗淨水由流入部10a流入入口 側流路25a時，氣泡沿著垂直方向之流路空間25而因為浮 力順利地上昇。進而，氣泡沿著朝向流出部l〇b變高之殼 體23的頂面而流入流出部10b。接著，氣泡由流出部10b 18 201242561 經由出水口 23b而排出到外部。 如第4圖所示，洗淨水由流入部l〇a流入流路空間25 之入口側流路25a。為流路厚度較薄之領域之入口側流路 25a中，洗淨水之流速較快。因此，平板狀加熱器20之各 傳熱面20a、20b與洗淨水之邊界層之速度梯度較大，各傳 熱面20a、20b與洗淨水之傳熱係數較大。而且’各傳熱面 20a、20b中，入口側流路25a中之電阻體之圖案20p之發 熱密度較高。因此，洗淨水被各傳熱面20a、20b加熱成為 高溫，並且其密度變小。藉此，洗淨水上昇，由入口側流 路25a流入出口側流路25b。 再者，由於入口側流路25a中之電阻體圖案20p的發 熱密度較高，因此各傳熱面20a、20b之溫度會變高。但是， 由於入口側流路25a中之洗淨水之溫度較低，因此過冷度 (相對於水之沸騰溫度的冷卻度）變大，洗淨水會由各傳 熱面20a、20b大量吸熱。進而’入口側流路25a中，流路 厚度較薄，洗淨水之流速較快。因此，傳熱係數較高，洗 淨水不會成為產生如局部沸騰現象之高溫。 出口側流路25b中’除了入口侧流路25a之強制對流 之外’由於密度不同，也產生自然對流。藉由該等，洗淨 水沿著各傳熱面20a、20b上昇。該洗淨水在入口側流路25a 被加熱，因此溫度較高。藉由該洗淨水，由各傳熱面2〇a、 20b吸取之熱較少，過冷度之値較小。因此，出口侧流路 25b中之各傳熱面20a、20b之溫度容易上昇。可是，由於 出口側流路25b中之發熱密度較小，因此隨著愈接近出水 19 201242561 口 23b’洗淨水之溫度漸漸上昇，但不會產生急速的沸騰。 藉此，可防止水垢附著於各傳熱面2〇a、2〇b之一部分。 又’假設即使發現各傳熱面2〇a、2〇13上產生之氣泡， 氣泡也可通過出口側流路25b中流路厚度較厚之出口側流 路25b而上昇。而且’氣泡由出水口 23b排出。 如此，成為高溫之洗淨水由出水口 23b流入供水路9。 洗淨水藉由槽（未圖示）等而調整溫度。而且，打開電磁 閥時’由噴嘴7吐出溫暖的洗淨水。 〔效果〕 藉由截面積漸漸變狹小之集管部節流流路45b，流速漸 漸變快。因此，即使係自來水配管中混入空氣之情況下， 亦可在氣泡大量成長之前，將氣泡推往下游，由集管部45 及流路空間25快速地排出。藉此，藉由氣泡，可防止各傳 熱面20a、20b中之洗淨水之流速不均一、各傳熱面20a、 20b成為局部過熱狀態。因此，可防止水垢附著於各傳熱面 20a、20b局部，縮小流路。藉此，確保必要之流量。又， 水垢造成各傳熱面20a、20b之溫度差，避免因熱應力而平 板狀加熱器20故障。 又’藉由集管部節流流路45b具有曲柄形狀，集管部 節流流路45b中之流路變長。因此，假設集管部節流流路 45b中之戴面積稍微變寬，集管部節流流路45b中可確保流 路阻力。藉此，洗淨水可佈及集管部主流路45a之全長而 一樣地流入集管部節流流路45b。 藉由集管部節流流路45b，流路空間25中，沿著各傳 20 201242561 熱面20a、20b之洗淨水形成均一且快速之流動。藉此’各 傳熱面20a、20b與洗淨水之傳熱係數變大。因此，可有效 率地將洗淨水加熱。又，可將各傳熱面20a、20b之溫度抑 制較低’減少水垢附著於各傳熱面20a、20b。進而，容易 去除各傳熱面20a、20b上產生之氣泡，防止局部的水垢之 發生及熱應力造成平板狀加熱器20的損壞，並且不會阻礙 傳熱面20a、20b與洗淨水之熱交換，可進行安定之熱交換。 特別是，入口側流路25a中較接近集管部節流流路 45b，且流路厚度較薄。因此，入口側流路25a中，維持來 自集管部節流流路45b之較快的流動。因此，各傳熱面 20a、20b與洗淨水之邊界層中之速度梯度較大，且各傳熱 面20a、20b與洗淨水之強制對流造成之傳熱係數較大。洗 淨水可有效率的被加熱，防止平板狀加熱器20之損壞。 進而，由於出口側流路25b中之各傳熱面2〇a、2〇b之 發熱密度較小’因此可防止局部的沸騰現象，藉此可防止 平板狀加熱器20之損壞。 又’平板狀加熱器20係藉内外之兩面傳熱面2〇a、2〇b 將洗淨水加熱，因此幾乎沒有散熱損失。因此，可實現熱 交換器10之較高熱效率，且可精簡化。 進而，即使出口側流路25b中，平板狀加熱器2〇亦可 抑制產生如局部的沸騰現象之咼溫’防止局部的水垢生 成。因此，將相較於金屬熱容量較小且容易破裂之陶曼使 用於平板狀加熱器20，也可防止其破裂，以達到衛生洗淨 裝置1之長壽命化。 21 201242561 又，假設於平板狀加熱器20，兩傳熱面20a、20b之各 自的傳熱量產生很大的不同，即使其中一流路之洗淨水局 部的沸騰，產生氣泡，亦可順利地將氣泡排出。因此，可 防止洗淨水之流路阻力會變高，2個流路之流量會不平均， 而於2個流路之傳熱量產生較大的差異。 進而，假設於流路空間25之流出部10b附近配設熱阻 器等之溫度感測器，溫度感測器亦可適當地檢測溫度。也 就是說，可藉由排出氣泡，氣泡不會變大。因此，可避免 大氣泡附著於溫度感測器，溫度感測器因為大氣泡而無法 與洗淨水接觸，而無法檢測出洗淨水之溫度的狀況。 又，藉洗淨水之強制對流及氣泡之排出，可抑制水垢 附著於傳熱面20a、20b。因此，為了避免水垢造成之傳熱 障礙，不需要增加傳熱面20a、20b之面積。因此，可防止 衛生洗淨裝置1之成本上昇，且達到精簡化。進而， 又，集管部節流流路45b之截面積漸漸變狹小，且流 路空間25中，入口側流路25a之截面積比出口側流路25b 更狹小。藉此，即使減少流路厚度，亦可形成沿著各傳熱 面20a、20b之洗淨水之均一的快速流動。 進而，藉由截面積漸漸變狹小之集管部節流流路45b、 與截面積較狹小之入口側流路25a，產生強制對流，傳熱面 20a、20b上之氣泡可快速地被推往上方。而且，在截面積 較寬的出口側流路25b中，即使是大氣泡亦可容易移動。 因此，氣泡可快速地往外部排出。藉此，洗淨水之流動均 22 201242561 又，各傳熱面20a、20b之發熱密度係出口側流路25b 比入口側流路25a小。相對於此，洗淨水之流速係入口側 流路25a比出口側流路25b大。因此，各傳熱面20a、20b 之熱通量係入口側流路25a比出口側流路25b高。藉此， 以達到傳熱面20a、20b之溫度均一化，可抑制水垢局部附 著。 〔其他例〕 上述實施形態2中，如第7圖所示，入口側流路25a 中之加熱線之寬度20s形成比出口側流路25b中之加熱線 之寬度20s細。但是，入口側流路25a中之電阻體之圖案 20p的發熱密度若是比出口側流路25b中之電阻體之圖案 20p的發熱密度高，則不限定於該加熱線之寬度20s。 例如，如第8圖所示，電阻體之圖案20p申，在入口 側流路25a中互相鄰接之加熱線的間隔20h比出口側流路 25b狹小。藉此，入口側流路25a中之電阻體之圖案20p 的發熱密度比出口側流路25b中之電阻體之圖案20p的發 熱密度高。 又，上述實施形態2中，集管部節流流路45b具有略 曲柄形狀，其流路截面積漸漸變狹小。集管部節流流路45b 之形狀不限定於略曲柄。例如，亦可由如第6圖所示之垂 直部45bb及水平部45bc之2邊所形成，其2邊以分別傾 斜之略「<」字形之截面形成集管部節流流路。又，流路 截面積不限定於階段地狹小者。例如，如第11圖所示，亦 可以間隔朝上方變狹小之三角形之截面形成集管部節流流 23 201242561 路。此種情況下，流路截面積會連續且漸漸縮小 進而，上述實施形態2中，各構件21、22中，藉由階 形棚部31、41，基座部30、40之Y方向的厚度可階段性 地變化。藉此，於流路空間25設有截面積不同之2個流路 25a、25b。相對於此，如第11圖所示，各構件21、22亦 可形成為基座部30、40之Y方向的厚度漸漸改變。此種情 況下，流路空間25設有截面積漸漸改變之1個流路。 又，上述全實施形態係只要彼此不排斥即可互相組合。 由上述說明，熟習此技藝者可明瞭本發明之多處改良 或其他實施形態。因此，上述說明可解釋為僅作為例示， 係以向熟習此技藝者教示實行本發明之最佳態樣之目的而 提供之。在不脫離本發明之精神之下，可實質變更其構造 及/或機能之細節。 産業上之利用可能性 本發明之衛生洗淨裝置係可用作為可確保必要之洗淨 水之流量，且可防止故障之衛生洗淨裝置等。 【圖式簡單說明】 第1圖係顯示本發明之實施形態2之衛生洗淨裝置裝 設於便器之狀態的立體圖。 第2圖係顯示裝載於第1圖之衛生洗淨裝置之熱交換 器之正面的平面圖。 第3圖係顯示第2圖之熱交換器之右側主面的平面圖。 第4圖係顯示沿著第2圖之A-A線而切斷之熱交換器 的橫截面圖。 24 201242561 第5圖係顯示沿著第3圖之B-B線而切斷之熱交換器 的縱截面圖。 第6圖係第4圖之C之領域之放大圖。 第7圖係顯示形成於第4圖之熱交換器之電熱線的平 面圖。 第8圖係顯示形成於第4圖之熱交換器之電熱線之變 形例的平面圖。 第9圖係顯示本發明之實施形態1之衛生洗淨裝置之 主要構成的模式圖。 第10圖係顯示裝載於第9圖之衛生洗淨裝置之熱交換 器的橫截面圖。 第11圖係顯示本發明之變形例之衛生洗淨裝置之主要 構成的核式圖。 【主要元件符號說明】 1...衛生洗淨裝置 10...熱交換器 2...便器 10a...流入部 3...本體部 10b...流出部 3a...框體 20...平板狀加熱器 4...便座部 20a, 20b.··傳熱面 5...便器蓋部 20h...加熱線的間隔 6...操作部 20k...陶瓷基體 7...噴嘴 20p...電阻體圖案 8...供水源 20s...加熱線的寬度 9...供水路 21...第1流路形成構件 25 201242561 22...第2流路形成構件 33...卡合溝 23...殼體 31，41...階形棚部 23a_._入水口 43...卡合突起 23b...出水口 45...集管部 23c...加熱器收容空間 45a...集管部主流路 25...流路空間 45b...集管部節流流路 25a...入口側流路 45bb…垂直部 25b...出口側流路 45bc…水平部 30, 40...基座部 30a，40a...主面 32, 42...凸緣部 45bd…垂直部 26There is a main flow path, and a header portion having a water inlet and a shape formed by the main flow path toward the front kombling state, and the flow portion of the header portion gradually decreasing in the inflow portion. Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the same or corresponding elements are designated by the same reference numerals, and the description thereof will be omitted. Further, a description will be given of a state in which the heat exchanger 10 is placed in the longitudinal direction so that the heat transfer surfaces 20a and 20b of the flat heater 2 are in the wrong direction. The Z direction shown in each drawing indicates the vertical direction. The X direction indicates a direction orthogonal to the vertical direction and parallel to the heat transfer surfaces 2a, 2b of the flat heater 20. The γ direction indicates a direction orthogonal to either the Z direction or the X direction. Further, the cross-sectional area indicates the area of the plane orthogonal to the flow of the washing water. (Embodiment 1) Fig. 9 is a schematic view showing the main configuration of the sanitary washing device i of the first embodiment. The sanitary washing device 1 has a nozzle 7; a water supply path 9 connectable to the upstream end of the water supply source 8 10 201242561 and connected to the nozzle 7 at the downstream end; and a heat exchanger 1 设置 disposed in the water supply path 9. The figure is a cross-sectional view showing the heat exchange benefit 10 of the sanitary washing device 1 of Fig. 9. The hot parent converter 10 has a casing 23 including an inflow portion i〇a, an outflow portion 10b located above the inflow portion 10a, a lower end portion communicating with the inflow portion 1〇a and an upper end portion communicating with the outflow portion 1b And the plate-shaped heater receiving space 23c formed in the vertical direction; the flat heater 2〇 is extended in the vertical direction to the heater accommodating space 23c of the casing 23, and includes the heater and the valley The heat transfer surfaces 20a and 20b of the main faces 3〇a and 40a of the space 23c are opposed to each other, and the gaps formed between the heat transfer surfaces 2a and 2b and the main faces 30a and 40a of the heater accommodating space 23c. Flow path space 25. The width of the gap of the flow path space 25 on the side of the inflow portion 10a is smaller than the width of the gap on the side of the outflow portion 丨〇b. Here, the term "up and down direction" includes both the vertical direction and the direction intersecting the vertical direction. The "heater accommodating space" is intended to include a space in which a heater exists and a space to be connected to the field, assuming that the heater is removed from the casing. The "flow path space" can be changed into a flow path in which a fluid (in this case, water) is introduced into the heat transfer surface along the __ of the flat heater. In the sanitary washing device i configured as described above, the washing water flows from the water supply source 8 through the water supply path 9. The washing water is in the water supply road 9 and the person heat exchange ^ 1 (), the brigade is heated here. The high-temperature washing water flows out of the heat exchanger 1G and is supplied to the nozzle 7. Thereby, warm water is ejected from the nozzle 7. Further, in the "Hot Father's Benefits 10", the washing water flows into the heater accommodating space 23c of the casing 23 201242561 from the inflow portion 10a. The washing water enters between the planar main faces 3〇a and 4〇a of the heater accommodating space 23c and the heat transfer surfaces 2〇a and 20b of the flat heater 2〇, and passes through the flow path space 25. At this time, the washing water is heated by the heat transfer surfaces 2a, 20b, and the temperature thereof rises. The width of the gap on the side of the inflow portion 10a in the flow path space 25 is smaller than the width of the gap on the side of the outflow portion 10b. Therefore, the forced convection of the washing water flowing in the flow path space 25 on the side of the inflow portion 10a becomes faster. Here, the velocity gradient of the boundary layer between the heat transfer surfaces 20a and 20b and the washing water is increased, and the heat transfer coefficient is increased. The heat transfer surfaces 20a and 20b transfer heat to the washing water, and the heat transfer surfaces 2a and 20b have a low temperature, and the scale is prevented from adhering to the heat transfer surfaces 20a and 20b. The washing water flows from the inflow portion 1 〇a side to the outflow portion 10b side by forced convection. In the side of the outflow portion 10b, the washing water is further heated on the heat transfer surfaces 20a, 20b. Thereby, the air mixed into the washing water expands and bubbles are generated. Since the width of the gap on the side of the outflow portion 10b is large, the air bubbles do not stay in the flow path space 25 and flow out to the outflow portion 10b. Further, when the temperature of the washing water rises, the density becomes small, and an upward flow of natural convection is generated, and the washing water flows to the outflow portion 10b. Since the width between the gaps on the side of the outflow portion 10b is large, the bubbles are easily removed by the upward flow of natural convection, and the heat transfer coefficient from the heat transfer surfaces 20a and 20b to the washing water is increased. According to the sanitary washing apparatus 1 having the above configuration, the air bubbles are smoothly discharged, and the heat exchange between the washing water and the heat transfer surfaces 20a and 20b is not hindered by the air bubbles, and the air bubbles can be stably settled. Also, by the bubble, one part of the washing water is retained, and the scale is reduced in the section 12 201242561. Therefore, the scale does not shrink the flow path space 25, and the washing water can smoothly flow, so that the washing water of the necessary flow rate can be secured. Further, the bubbles do not adhere to the heat transfer surfaces 20a and 20b, and this portion can be prevented from becoming high in temperature, and a temperature difference occurs in the heat transfer surfaces 20a and 20b. Thereby, the heat transfer surfaces 20a, 20b are not deformed and damaged by the thermal stress caused by the temperature difference, and the flat heater 20 can be prevented from malfunctioning. (Embodiment 2) [Configuration of Sanitary Washing Apparatus] Fig. 1 shows a toilet in which the sanitary washing apparatus 1 of the second embodiment is installed in the toilet 2. The sanitary washing device 1 is disposed above the toilet 2. The sanitary washing device 1 has a main body portion 3, a toilet seat portion 4, a toilet lid portion 5, and an operation portion 6. The main body portion 3 is disposed on the rear side of the toilet seat portion 4, that is, the rear side of the toilet seat portion 4, that is, the seated user. The main body portion 3 is a horizontally long casing 3a, and houses the water supply passage 9 and the heat exchanger 10 shown in Fig. 9. Further, in addition to the above, the main body unit 3 also houses a cleaning unit (not shown), a drying unit, and a control unit for controlling the operations. The water supply path 9 introduces tap water (fluid, liquid, and washing water) to the nozzle 7 via the heat exchanger 10 from the water supply device (water supply source 8) attached to the toilet 2. When the user operates the operation unit 6 and performs a predetermined input, the cleaning unit is driven. The washing water is heated in the heat exchanger 10, and the warm water is spouted from the opening of the toilet 2 by the nozzle 7. [Configuration of Heat Exchanger] Fig. 2 is a plan view showing the front surface of the heat exchanger 10. Fig. 3 is a plan view showing the right main surface of the heat exchanger 1G. (4) shows a cross-sectional view of the heat exchanger cut off after the 图·Α line in Fig. 2 shows a heat exchanger 1 沿着 surface along the Ββ line of Fig. 3 . Fig. 6 is an enlarged view of the field of c in Fig. 4. The heat exchanger 10 has a small thickness in the Y direction and a rectangular shape in the core. As shown in Fig. 4, the heat exchanger 10 has a flat-plate twister 20, a first flow path forming member 21, and a second flow path forming member U. The first flow path forming member 21 and the second flow path forming member are formed into a casing 23. The first flow path forming member η and the second flow path forming member 22 are reinforced by, for example, a composite of glass fibers into ABs resin. A fat is formed. & The first flow path member 21 is on the side of the flat heating ϋ 20 - the heat transfer surface 20a side. The first flow path forming member 21 includes a base portion % and a stepped shed portion 31. The base portion 30 includes a base surface (main surface) 30a, and the base surface 3 has a planar shape and faces the first heat transfer surface 2A. In the stepped shed 31, the thickness of the base portion 30 in the Y direction changes. The thickness of the base portion 30 from the stepped shed portion η to the outflow portion (10) side is smaller than that from the stepped shed portion 31 to the inflow portion 10a side. Therefore, the base surface 30a from the stepped shed portion 31 to the inflow portion (10) side is closer to the first heat transfer surface 20a than the base portion φ on the outflow portion side. The inflow portion 10M has a width between the base surface 3〇a and the first heat transfer surface 2〇& and a width between the base surface 3〇a and the first heat transfer surface 2〇a on the 1% side of the outflow portion. The width is narrow. The first flow path forming member 21 includes a flange portion 32 having a wall shape on the entire periphery of the base portion. An engagement groove 14 201242561 33 is formed at an end portion of the flange portion 32, and the card σ / 冓 33 is formed along the flange portion 32 including the entire circumference thereof. The second flow path forming member 22 is disposed on the second heat transfer surface 20b side of the flat heater 20. The second flow path forming member includes a base #仙 and a stepped shed 41. The base portion 40 includes a base © (main surface) 40a, and the base surface 40a has a planar shape and faces the second heat transfer surface. In the stepped shed portion W, the thickness of the base portion 40 in the Y direction is changed. The thickness of the pedestal #4〇 from the stepped shed portion μ to the outflow portion l〇b side is smaller than that from the stepped shed portion 41 to the inflow portion gamma side. Therefore, the pedestal surface from the stepped shed 41 to the inflow side is closer to the second heat transfer surface than the pedestal surface 4 〇a on the side of the machine 4 10b. The width between the base surface 4〇a and the second heat transfer surface 2〇b on the inflow portion 10a side is narrower than the width between the base self-shirt and the second heat transfer surface 2 (10) on the flow tIMOb side. The peripheral portion of the base portion 40 includes a flange portion 42 having a full circumference = wall shape. The flange portion & is opposite to the side of the base surface; the front end portion of the flange portion 42 is folded back on the side of the base surface. The front W is formed over the entire circumference of the engaging projection 42. 3, the flange of the flange member 21 of the second flow path forming member 22, the convex portion of the flange portion 21 forming the protrusion 43\', and the card of the card-shaped projection path forming member 21 of the second type of the money member 22 Closure 33. For example, the card super-a wave is welded and fixed to the engagement groove 33. Thereby, the first λ melon forming member 21 and the second flow path # are formed into the casing 23. The twisting member 22 is sealingly joined, and the shape body 23 has a side surface, a (10) main surface, a top surface, and a bottom surface ' and 15 201242561 includes a substantially rectangular hollow portion surrounded by the same. The slightly rectangular hollow portion constitutes a plate-shaped heater accommodating space 23C. The heater accommodating space 23c extends in the up and down direction. The lower end portion of the heater accommodating space 23c communicates with the inflow portion 10a' and the upper end portion communicates with the two side faces of the outflow portion 10b < jY_z direction. On one of the side faces, the water inlet port 23a and the water outlet port 23b are open. The opening of the water outlet 23b serves as an outflow portion lb. The water inlet 23a is provided at a lower end of one side of the side surface and is connected to the upstream end of the water supply path 9 (Fig. 9). The water outlet 23b s is placed at the upper end of one side of the side and connected to the downstream end of the water supply path 9 (Fig. 9). The two main faces in the X-Z direction are formed by the base faces 3〇a and 4〇a, respectively. The top surface faces the upper end of the flat heater 2〇. The top surface is inclined closer to the water outlet 23b, and the gap between the top surface and the upper end of the flat heater 2 is wider. The bottom surface faces the lower end of the flat heater 2〇. The inflow portion 10a of the flow path space 25 is open at the top surface, and the inflow portion 1A is extended in the χ direction. A flow path space 25 and a header portion 45 are formed inside the casing 23. The flow path space 25 includes a flow path between the "il path between the first heat transfer surface 20a and the base surface 30a, and between the second heat transfer surface 2'b and the base surface 40a. The two flow paths are symmetrically formed on both sides of the flat heater 20. The two flow paths have an inlet side flow path 25a and an outlet side flow path 25b, respectively. The inlet side flow path 25a is provided on the side of the water inlet 23a near the lower portion of the relatively stepped shed portion 31'41. The outlet side flow path 25b is provided on the side of the water outlet 23b near the upper portion of the stepped shed portions 31, 41. The thickness in the γ-axis direction of the inlet-side flow path 25a is smaller than the thickness in the γ-axis direction of the outlet-side flow path 25b. The center portion 45 is disposed between the inflow portion 10a of the flow path space 25 and the water inlet port 23a as shown in Fig. 6, and extends in the weir direction. The header portion 45 16 201242561 includes a center portion main flow path 45a and a header portion throttle flow path 45b. The cross-sectional area of the flow path in the X-Y direction in the main flow path 45a of the header portion is wider than that in the header portion. That is, the flow path cross-sectional area in the X-Y direction is orthogonal to the flow of the washing water flowing from the human water port 23a to the inflow portion i〇a. The cross-sectional area of the flow path of the header throttle channel 45b is gradually narrowed by the main flow path of the header portion and from the inflow portion 10a toward the inflow portion 10a. The header throttle channel 4 has a crank shape. The header throttle channel 45b includes a vertical portion 45bb, a horizontal portion 45bc, and a vertical portion 45bd. The cross-sectional area thereof becomes smaller (i.e., becomes narrower) in accordance with the order of the vertical portion 45bb, the horizontal portion 45bc, and the vertical portion 45bd. The flat heater 20 is housed in the heater accommodating space 23c' of the casing 23 and extends in the vertical direction. The flat heater 2 has a rectangular flat shape and includes first and second heat transfer surfaces 2a, 2b on both sides. The flat heater 20 includes a ceramic base 20k, a resistor pattern 2〇p, and an electrode (not shown). The temperature of the heat transfer surfaces 20a, 20b is prevented from being locally higher than a predetermined temperature. The predetermined temperature is generally set at a temperature of 2 〇 3, 2% of the heat transfer surface at a boiling of 100. (The following is preferably 80. (The following. Further, the predetermined temperature is appropriately determined by the scale concentration of the tap water or the required endurance time of the heater, etc. The resistor pattern 20p is printed with a resistor body on the ceramic base 20k. The resistor pattern 20p constitutes a heating wire (heating wire), and generates heat by energization from the electrode. As shown in Fig. 7, the heater wire extends long in the χ direction and snakes and expands toward the upper side in the ζ direction. The width 20s of the heating wire in the inlet side flow path 25a is smaller than the width 2〇s of the heating wire in the outlet side flow path 25b, and the cross-sectional area of the heating wire is small. The width of the heating wire is 2 〇s thin, and The addition of 17 201242561 The smaller the cross-sectional area of the hot wire, the larger the resistance value of the heating wire. Therefore, the resistance value of the heating wire in the inlet side flow path 25a is higher than the resistance value of the heating wire in the outlet side flow path 25b. The heat generation density of the pattern 20p of the resistor in the inlet side flow path 25a is higher than the heat generation density of the pattern 20p of the resistor in the outlet side flow path 25b. [Flow of the washing water in the sanitary washing device] As shown, when opening the solenoid valve, The purified water flows into the water supply path 9 from the tap water pipe of the water supply source 8 via the branch tap. As shown in Fig. 3 and Fig. 4, the washing water flows into the casing 23 through the water inlet port 23a through the water supply path 9. As shown in Fig. 6 , the washing water enters the header main flow path 45a of the header portion 45. The cross-sectional area of the header portion throttle passage 45b is very small compared to the cross-sectional area of the header main passage 45a. Therefore, the resistance of the header main flow passage 45a to the header throttle passage 45b is larger than the resistance of the header main passage 45a in the X direction. Therefore, most of the washing water flows to the header main passage 45a. In the X direction, the washing water is filled in the header main flow path 45a, and the washing water flows from the header main flow path 45a to the header throttle flow path 45b. The flow path of the header throttle flow path 45b is cut. The area will gradually become smaller and smaller, so the flow of the washing water will gradually increase. In addition, the throttle section flow channel 45b has no place where air can be retained. Therefore, even if air is mixed in the washing water, the air does not stay and is transported to The inflow portion 10a side. When the washing water flows into the inlet side flow path 25a from the inflow portion 10a, the bubble is vertical The buoyancy smoothly rises in the flow path space 25 in the direction. Further, the air bubbles flow into the outflow portion 10b along the top surface of the casing 23 that is higher toward the outflow portion 10b. Then, the air bubbles are discharged from the outflow portion 10b 18 201242561 The water inlet 23b is discharged to the outside. As shown in Fig. 4, the washing water flows into the inlet side flow path 25a of the flow path space 25 from the inflow portion 10a. The inlet side flow path 25a is in the field where the flow path thickness is thin. The flow rate of the washing water is faster. Therefore, the speed gradient of the boundary layers of the heat transfer surfaces 20a and 20b of the flat heater 20 and the washing water is large, and the heat transfer surfaces 20a and 20b and the washing water are transmitted. The heat coefficient is large, and in the heat transfer surfaces 20a and 20b, the heat generating density of the pattern 20p of the resistor in the inlet side flow path 25a is high. Therefore, the washing water is heated to a high temperature by the respective heat transfer surfaces 20a, 20b, and the density thereof becomes small. Thereby, the washing water rises and flows into the outlet side flow path 25b from the inlet side flow path 25a. Further, since the heat generation density of the resistor pattern 20p in the inlet side flow path 25a is high, the temperature of each of the heat transfer surfaces 20a and 20b becomes high. However, since the temperature of the washing water in the inlet side flow path 25a is low, the degree of subcooling (cooling degree with respect to the boiling temperature of water) becomes large, and the washing water absorbs a large amount of heat from the respective heat transfer surfaces 20a, 20b. . Further, in the inlet side flow path 25a, the flow path thickness is thin, and the flow rate of the washing water is fast. Therefore, the heat transfer coefficient is high, and the washing water does not become a high temperature such as partial boiling. In the outlet side flow path 25b, except for the forced convection of the inlet side flow path 25a, natural convection also occurs due to the difference in density. By these, the washing water rises along the respective heat transfer surfaces 20a, 20b. Since the washing water is heated in the inlet side flow path 25a, the temperature is high. With the washing water, the heat absorbed by each of the heat transfer surfaces 2a, 20b is less, and the degree of subcooling is small. Therefore, the temperature of each of the heat transfer surfaces 20a and 20b in the outlet side flow path 25b is likely to rise. However, since the heat generation density in the outlet side flow path 25b is small, the temperature of the washing water gradually rises as it approaches the water discharge 19 201242561, but the rapid boiling does not occur. Thereby, it is possible to prevent scale from adhering to one of the heat transfer surfaces 2a, 2b. Further, even if bubbles are generated on the respective heat transfer surfaces 2a, 2, 13, the bubbles can be raised through the outlet side flow path 25b having a thick flow path in the outlet side flow path 25b. Further, the bubble is discharged from the water outlet 23b. In this way, the washing water that has become high temperature flows into the water supply path 9 from the water outlet 23b. The washing water is adjusted in temperature by a tank (not shown) or the like. Further, when the electromagnetic valve is opened, warm washing water is discharged from the nozzle 7. [Effects] The flow velocity is gradually increased by the header throttle flow path 45b whose cross-sectional area is gradually narrowed. Therefore, even if air is mixed into the tap water pipe, the bubble can be pushed downstream before the bubble grows a lot, and the header portion 45 and the flow path space 25 can be quickly discharged. Thereby, by the air bubbles, the flow velocity of the washing water in each of the heat transfer surfaces 20a and 20b can be prevented from being uneven, and the heat transfer surfaces 20a and 20b become partially superheated. Therefore, it is possible to prevent scale from adhering to the respective heat transfer surfaces 20a and 20b and to narrow the flow path. In this way, the necessary flow is ensured. Further, the scale causes a temperature difference between the heat transfer surfaces 20a and 20b to prevent the flat heater 20 from malfunctioning due to thermal stress. Further, the header throttle passage 45b has a crank shape, and the flow passage in the header throttle passage 45b becomes long. Therefore, it is assumed that the wearing area in the header throttle passage 45b is slightly widened, and the flow path resistance can be secured in the header throttle passage 45b. Thereby, the washing water can flow into the header throttle passage 45b in the same manner as the entire length of the header main passage 45a. By the header throttle passage 45b, the flow of the washing water along the hot faces 20a and 20b of each of the passages 20 201242561 forms a uniform and rapid flow. Thereby, the heat transfer coefficients of the respective heat transfer surfaces 20a and 20b and the washing water become large. Therefore, the washing water can be heated efficiently. Further, the temperature of each of the heat transfer surfaces 20a and 20b can be kept low, and the scale is reduced to adhere to the respective heat transfer surfaces 20a and 20b. Further, it is easy to remove the air bubbles generated on the respective heat transfer surfaces 20a, 20b, prevent local scale generation and thermal stress from causing damage to the flat heater 20, and do not hinder the heat of the heat transfer surfaces 20a, 20b and the washing water. Exchange, can carry out the heat exchange of stability. In particular, the inlet side flow path 25a is closer to the header portion throttle flow path 45b, and the flow path thickness is thin. Therefore, in the inlet side flow path 25a, a relatively fast flow from the header throttle passage 45b is maintained. Therefore, the velocity gradient in the boundary layer between each of the heat transfer surfaces 20a and 20b and the washing water is large, and the heat transfer coefficient of the forced convection of each of the heat transfer surfaces 20a and 20b and the washing water is large. The washing water can be heated efficiently to prevent damage to the flat heater 20. Further, since the heat transfer surfaces 2a, 2b in the outlet side flow path 25b have a small heat generation density, a partial boiling phenomenon can be prevented, whereby the damage of the flat heater 20 can be prevented. Further, the flat heater 20 heats the washing water by the heat transfer surfaces 2〇a and 2〇b on both the inner and outer sides, so that there is almost no heat loss. Therefore, the higher thermal efficiency of the heat exchanger 10 can be achieved and can be simplified. Further, even in the outlet side flow path 25b, the flat heater 2 can suppress the occurrence of a partial boiling phenomenon, which prevents local scale formation. Therefore, it is possible to prevent the rupture of the flat heater 20 as compared with the case where the metal heat capacity is small and the rupture is easy, so that the sanitary cleaning apparatus 1 can be extended in life. 21 201242561 In addition, it is assumed that the heat transfer amount of each of the two heat transfer surfaces 20a and 20b is greatly different in the flat heater 20, and even if the boiling water of the first-stage road is partially boiled, bubbles are generated, and it is possible to smoothly The bubbles are discharged. Therefore, it is possible to prevent the flow path resistance of the washing water from becoming high, the flow rates of the two flow paths are not uniform, and the heat transfer amounts of the two flow paths are largely different. Further, it is assumed that a temperature sensor such as a thermal resistor is disposed in the vicinity of the outflow portion 10b of the flow path space 25, and the temperature sensor can appropriately detect the temperature. That is, the bubbles do not become large by discharging the bubbles. Therefore, it is possible to prevent the large bubbles from adhering to the temperature sensor, and the temperature sensor cannot be in contact with the washing water due to the large bubbles, and the temperature of the washing water cannot be detected. Further, by forced convection of the washing water and discharge of the air bubbles, it is possible to suppress the scale from adhering to the heat transfer surfaces 20a and 20b. Therefore, in order to avoid heat transfer obstacles caused by scale, it is not necessary to increase the area of the heat transfer surfaces 20a, 20b. Therefore, the cost of the sanitary washing device 1 can be prevented from rising and the simplification can be achieved. Further, the cross-sectional area of the header throttle passage 45b is gradually narrowed, and in the flow space 25, the cross-sectional area of the inlet-side passage 25a is narrower than that of the outlet-side passage 25b. Thereby, even if the thickness of the flow path is reduced, a uniform rapid flow of the washing water along the respective heat transfer surfaces 20a, 20b can be formed. Further, by the header throttle passage 45b having a narrow cross-sectional area and the inlet-side passage 25a having a narrow cross-sectional area, forced convection is generated, and the bubbles on the heat transfer surfaces 20a and 20b can be quickly pushed to Above. Further, in the outlet side flow path 25b having a wide cross-sectional area, even large bubbles can be easily moved. Therefore, the bubbles can be quickly discharged to the outside. Thereby, the flow of the washing water is 22 201242561 Further, the heat generation density of each of the heat transfer surfaces 20a and 20b is smaller than the inlet side flow path 25a. On the other hand, the flow rate of the washing water is larger than the outlet side flow path 25b. Therefore, the heat flux of each of the heat transfer surfaces 20a and 20b is higher than the outlet side flow path 25b. Thereby, the temperature of the heat transfer surfaces 20a and 20b is made uniform, and the scale adhesion can be suppressed. [Others] In the second embodiment, as shown in Fig. 7, the width 20s of the heating wire in the inlet-side flow path 25a is formed to be smaller than the width 20s of the heating wire in the outlet-side flow path 25b. However, if the heat generation density of the pattern 20p of the resistor in the inlet side flow path 25a is higher than the heat generation density of the pattern 20p of the resistor in the outlet side flow path 25b, the width of the heating line is not limited to 20 s. For example, as shown in Fig. 8, the pattern 20p of the resistor body is such that the interval 20h of the heater lines adjacent to each other in the inlet side flow path 25a is narrower than the outlet side flow path 25b. Thereby, the heat generation density of the pattern 20p of the resistor in the inlet side flow path 25a is higher than the heat generation density of the pattern 20p of the resistor in the outlet side flow path 25b. Further, in the second embodiment, the header throttle passage 45b has a slightly crank shape, and the flow passage cross-sectional area is gradually narrowed. The shape of the header throttle passage 45b is not limited to the slightly crank. For example, it may be formed by two sides of the vertical portion 45bb and the horizontal portion 45bc as shown in Fig. 6, and the two sides thereof form a header throttle passage in a section of a "<" shape which is inclined. Further, the flow path cross-sectional area is not limited to those that are narrow in stages. For example, as shown in Fig. 11, it is also possible to form a header throttle flow 23 201242561 by a section of a triangle which is narrowed toward the upper side. In this case, the cross-sectional area of the flow path is continuously and gradually reduced. In the second embodiment, the thickness of the base portions 30 and 40 in the Y direction by the stepped shed portions 31 and 41 is also included in each of the members 21 and 22. It can change in stages. Thereby, two flow paths 25a and 25b having different cross-sectional areas are provided in the flow path space 25. On the other hand, as shown in Fig. 11, the members 21 and 22 may be formed such that the thicknesses of the base portions 30 and 40 in the Y direction gradually change. In this case, the flow path space 25 is provided with one flow path whose sectional area gradually changes. Further, the above-described entire embodiments can be combined with each other as long as they do not exclude each other. From the above description, many modifications and other embodiments of the invention will be apparent to those skilled in the art. Accordingly, the description is to be construed as illustrative only, The details of construction and/or function may be varied substantially without departing from the spirit of the invention. Industrial Applicability The sanitary washing device of the present invention can be used as a sanitary washing device that can ensure the flow rate of necessary washing water and prevent malfunction. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a state in which a sanitary washing device according to a second embodiment of the present invention is installed in a toilet. Fig. 2 is a plan view showing the front surface of the heat exchanger mounted in the sanitary washing apparatus of Fig. 1. Fig. 3 is a plan view showing the right main surface of the heat exchanger of Fig. 2. Fig. 4 is a cross-sectional view showing the heat exchanger cut along the line A-A of Fig. 2; 24 201242561 Fig. 5 is a longitudinal sectional view showing a heat exchanger cut along line B-B of Fig. 3. Fig. 6 is an enlarged view of the field of Fig. 4C. Fig. 7 is a plan view showing a heating wire formed in the heat exchanger of Fig. 4. Fig. 8 is a plan view showing a modification of the electric heating wire formed in the heat exchanger of Fig. 4. Fig. 9 is a schematic view showing the main configuration of the sanitary washing device according to the first embodiment of the present invention. Fig. 10 is a cross-sectional view showing the heat exchanger mounted in the sanitary washing device of Fig. 9. Fig. 11 is a nucleus diagram showing the main constitution of a sanitary washing device according to a modification of the present invention. [Description of main component symbols] 1: Sanitary washing apparatus 10... Heat exchanger 2... Toilet 10a... Inflow part 3... Main part 10b... Outflow part 3a... Frame 20...flat heater 4...seat portion 20a, 20b.·heat transfer surface 5... toilet lid portion 20h...interval of heating line 6...operation portion 20k...ceramic substrate 7...nozzle 20p...resistor pattern 8...water supply source 20s...heat line width 9...water supply path 21...first flow path forming member 25 201242561 22...2 Flow path forming member 33... Engagement groove 23... Housing 31, 41... Stepped shed 23a_._Water inlet 43... Engagement protrusion 23b... Water outlet 45... Tube portion 23c...heater accommodating space 45a... header portion main flow path 25...flow path space 45b... header portion throttle flow path 25a...inlet side flow path 45bb...vertical portion 25b ...outlet side flow path 45bc...horizontal part 30, 40...base part 30a,40a...main side 32,42...flange part 45bd...vertical part 26