JP4293007B2 - Heat exchanger and sanitary washing device equipped with the same - Google Patents

Description

  The present invention relates to a heat exchanger provided with a heater that heats cold water to warm water, and a sanitary washing device that cleans a local part of the human body using the heat exchanger.

  Conventionally, this type of heat exchanger has a double tube structure including a cylindrical base pipe 1 and an outer cylinder 2 as shown in FIG. A heater unit 3 is provided on a part of the outer surface of the base pipe 1. A spiral core 5 is inserted into the inner hole 4 of the base pipe 1 (see, for example, Patent Document 1).

In the above configuration, water as a fluid flows through the inner hole 4 of the base pipe 1, and at this time, the water is inserted into the inner hole 4 of the base pipe 1 to the screw thread 6 of the spiral core 5. The hot water is discharged by exchanging heat with the heat from the heater section.
JP 2001-279786 A

  However, in the conventional configuration, since the heater portion is provided outside the base pipe, an outer cylinder for enclosing and insulating the heater portion is necessary, which is a large configuration. Moreover, since the heat of the heater part escapes to the outside, there is a problem that heat exchange efficiency is poor. Furthermore, in order to insert and hold the helical core in the inner hole, it is necessary to make contact with the inner surface of the base material pipe where the heater is located, and there is a restriction that the helical core must be made of a thermally strong material. there were.

  An object of the present invention is to reduce scale adhesion of a heat generating part by providing a spiral guide in a small heat exchanger having high heat exchange efficiency and a sanitary washing apparatus using the heat exchanger.

In order to solve the conventional problems, a heat exchanger according to the present invention and a sanitary washing device using the heat exchanger include a flow path provided on an outer periphery of a heating element, a case constituting the flow path, and the flow path. A spiral guide that converts a flow direction into a swirl direction, and the spiral guide is slidably held on at least a surface of the heating element so as to vibrate by a flow force in the flow path. Is.

  Accordingly, since the heat insulation is performed by the flow path by providing the flow path on the outer periphery of the heating element, it is not necessary to provide a thermal insulating layer, and the size can be reduced. And it can be set as the structure which does not escape heat outside by enclosing a heat-emitting part with a flow path, and can improve heat exchange efficiency.

  In addition, since the spiral guide provided in the flow path can be held by the inner wall of the case at a low temperature, it can be used with materials with low heat resistance such as resin, so it has excellent workability and should be lightweight. Can do.

And by changing the direction of the water flowing in the flow path to the swirl direction by the spiral guide, the apparent flow cross-sectional area is reduced. Can speed up. When the flow rate is increased, the boundary layer between water and the heating element is narrowed, so that an increase in the surface temperature of the heating element can be prevented, and adhesion of scales and the like generated on the surface of the heating part can be reduced. Furthermore, since the spiral guide is vibrated by the flow force in a configuration in which at least a part is slidably held, there is an action of peeling the scale, and since the flow rate is high, heat exchange is performed without depositing the scale. It can be discharged out of the vessel with running water.

  Furthermore, since the direction of water flowing in the flow path is smoothly guided in the swirl direction, a heat exchanger with little pressure loss can be realized.

The heat exchanger according to the present invention and the sanitary washing apparatus equipped with the heat exchanger vibrate by the force of the flow by at least partly installing a spiral guide in a flow path provided on the outer periphery of the heating element. It has the effect of peeling the scale and can increase the flow rate of the water flowing in the flow path, reduce the adhesion of the heat generating part surface and the scale generated in the flow path, etc. can do.

1st invention is equipped with the flow path provided in the outer periphery of a heat generating body, the case which comprises the said flow path, and the spiral guide which converts a flow direction into the turning direction in the said flow path , The said spiral guide is The apparent cross-sectional area of the flow path is reduced by adopting a configuration in which at least the surface of the heating element is slidably held so as to vibrate by the flow force in the flow path. The flow velocity of water flowing in the passage is increased, and the spiral guide vibrates by the force of the flow and acts to peel off the scale, reducing the deposits such as the scale generated on the surface of the heat generating part and the flow path. It can be small, achieve high efficiency and have a long life. Furthermore, since the direction of the water flowing in the flow path is guided smoothly and in the swirl direction by the spiral guide, a heat exchanger with little pressure loss can be realized.

  The second invention reduces the pressure loss of the flow path by partially widening the pitch, in particular, by adopting a configuration in which the pitch of the spiral guide of the first invention is made non-uniform. Can do.

  In the third invention, in particular, the temperature of the heating element is increased by adopting a configuration in which the pitch of the spiral guide of the second invention is narrowed in a region where the surface temperature of the heating element is equal to or higher than a predetermined temperature. Since the flow rate in the region can be increased, the temperature of the heating element can be effectively prevented from rising excessively, and the amount of scale adhesion can be reduced.

  In the fourth aspect of the invention, in particular, the scale on the downstream side of the spiral guide of the second or third aspect is relatively easy to cause scale adhesion by adopting a configuration in which the pitch is narrowed on the downstream side of the flow path. Can be reduced, and pressure loss in the flow path can be reduced as compared with narrowing the flow path in the entire area.

  In the fifth aspect of the invention, in particular, in the second to fourth aspects of the invention, the pitch is continuously narrowed toward the downstream side of the flow path of the spiral guide, so that the scale adhesion is likely to occur downstream. The flow rate is continuously increased as it goes, so that the adhesion of scale can be effectively reduced, and the pressure loss of the flow path can be reduced as compared with the case where the flow path in the entire area is narrowed.

  In the sixth aspect of the invention, in particular, in the second to fourth aspects of the invention, the pitch is intermittently narrowed toward the downstream side of the flow path of the spiral guide, so that the scale adhesion is likely to occur downstream. The flow rate is intermittently increased as it goes, and scale adhesion can be effectively reduced, and pressure loss in the flow path can be reduced as compared with narrowing the flow path in the entire area.

  In the seventh aspect of the invention, in particular, the sanitary washing apparatus provided with the heat exchanger according to the first to sixth inventions can realize a reduction in the size of the sanitary washing apparatus body by downsizing the heat exchanger, and a narrow toilet space. In addition, it is possible to prevent the scale nozzle from clogging in the cleaning nozzle of the sanitary cleaning device by preventing the scale from adhering at an early stage. It can be.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
FIG. 1 is a sectional view of a heat exchanger according to the first embodiment of the present invention.

  In FIG. 1, the heat exchanger includes a sheathed heater 7 as a heating element that heats water as a fluid, a case 9 that surrounds the outer periphery of the sheathed heater 7 to form a flow path 8, and water in the flow path 8. The spiral spring 10 is a spiral guide for inducing a flow in the turning direction. And the inflow port 11, the outflow port 12, the electrode terminals 13 and 14 of a sheathed heater, and the O-ring 15 for sealing a flow path are provided. In addition, 16 arrows in the figure indicate the flow of water.

  About the heat exchanger comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, as shown in FIG. 2, the sheathed heater 7 as a heating element has a heating wire 18 disposed in a coil shape in a copper pipe 17 in which magnesium oxide (not shown) is sealed. . Then, by supplying electricity to the electrode terminals 13 and 14 connected to the heating wire 18, the heating wire 18 is heated, and heat is transmitted to the copper pipe 17 through the magnesium oxide, so that the outer periphery of the copper pipe 17 is The flowing water is heated to become warm water and heat exchange is performed.

  At this time, as shown in FIG. 3, water enters the inlet 11 provided at the side surface position eccentric from the center of the case 9, flows into the outer periphery of the copper pipe 17, and further along the outer periphery of the copper pipe 17. The spiral spring 10 arranged in a spiral manner flows around the outer periphery of the copper pipe 17 as shown by an arrow 16 and is again discharged from the discharge port 12 provided at the side surface position eccentric from the center of the case 9. Become.

  Here, the spiral spring 10 arranged in a spiral shape has a flow path cross-sectional area constituted by a pitch between the spiral springs 10 that is an apparent flow path cross-sectional area and a gap between the sheathed heater 7 and the case 9. And the copper pipe 17 are swung in a direction and a pitch so as to be narrower than the cross-sectional area of the donut-shaped channel. As a result, the flow velocity of the swirling flow 16 that flows spirally along the spiral spring 10 becomes faster than when the spiral spring 10 is not provided. For example, when the outer diameter of the sheathed heater 7 is φ6.5 mm, the inner diameter of the case 9 is φ9 mm, and the pitch of the springs 10 is 6 mm, the cross-sectional area of the passage without the spiral spring 10 is about 30 mm2. Since the apparent flow path cross-sectional area when the spiral spring 10 is used is about 7.5 mm 2, the flow rate can be increased about 4 times when the same flow rate is applied. Further, by making the water flow 16 swirl, the pressure loss does not increase relatively even if the flow path cross-sectional area is reduced. Furthermore, by providing the inflow port 11 and the outflow port 12 at a side surface position eccentric from the center of the case 9 and using a spiral guide, the water flow 16 in the flow path 8 is smoothly guided in the turning direction. Therefore, the pressure loss can be reduced.

  Further, when the distance through which the fluid flows becomes long, the rectifying effect is gradually activated, and the turning force is weakened to flow along the sheathed heater 7. In that case, since the cross-sectional area of the flow path becomes wide, the flow velocity decreases. However, in the present invention, since the swirl flow is sustained to the outlet 12 by the spiral spring 10, a high flow rate can be maintained, so the boundary layer of the copper pipe 17 in the flow path 8 and the water that is fluid This area becomes very narrow over the entire area. A flow velocity distribution diagram showing this state is schematically shown in FIGS. As shown in FIG. 4, when the flow velocity is low, the boundary layer 19 becomes wide. However, when the flow velocity is high and the water flow becomes turbulent, the flow becomes narrow like the boundary layer 20 of the flow velocity distribution shown in FIG. The surface temperature of the pipe 17 does not rise excessively. In general, since the amount of precipitation of the scale component increases as the temperature increases, the flow rate of the water flowing in the flow path 8 is increased as in the present embodiment, and the boundary layer region between the copper pipe 17 and the water is narrowed. Thus, it is possible to suppress an increase in the surface temperature of the copper pipe 17, and as a result, the amount of scale attached to the copper pipe 17 can be reduced. In this embodiment, in order to enhance the effect of reducing the scale amount, the flow velocity is increased until the turbulent flow is generated by the spiral spring 10 which is a spiral guide. Since the area of the boundary layer between the copper pipe 17 and the water can be narrowed by increasing the flow velocity by the spiral spring 10 that is a guide for the above, a scale reduction effect can be obtained.

  Furthermore, even when the scale is deposited on the copper pipe 17, the flow rate of the water flowing in the flow path 8 is high, so that the deposited scale has an effect of flowing downstream, and the scale is crushed small and flows downstream. As it goes, there is no clogging downstream. And since a scale becomes difficult to adhere in a heat exchanger, the lifetime as a heat exchanger can be extended. Moreover, by making it a smooth flow of a spiral, it is possible to reduce pressure loss of the flow path 8 while having a high flow rate, and to improve the heat exchange efficiency by narrowing the boundary layer between the copper pipe 17 and water. And miniaturization can be realized.

  In this way, the flow path 8 is configured by the case 9 provided on the outer periphery of the sheathed heater 7 that is a heating element, and the flow path 8 is provided with the spiral spring 10 that is a spiral guide. The flow rate of the water flowing in the path 8 can be increased, and deposits such as scales generated on the surface of the copper pipe 17 can be peeled off or pulverized. Further, the flow velocity is increased and the interface between the copper pipe 17 and the water is narrowed, so that a small size and high efficiency can be realized, and the scale adhesion can be reduced and the life can be extended. In addition, by increasing the flow rate, the generation of bubbles can be reduced, the generation of scale can be suppressed, and the temperature of the surface of the copper pipe 17 can be suppressed low, so the generation of boiling noise can be reduced. And since the heat insulation is performed by the flow path 8 by providing the flow path 8 in the outer periphery of the sheathed heater 7 which is a heat generating body, it is not necessary to provide a thermal insulation layer, and it can be reduced in size. Moreover, it can be set as the structure which does not escape heat outside by enclosing the heat generating part with the flow path 8, and can improve heat exchange efficiency.

  Further, the spiral spring 10 that is a spiral guide is configured to use a member different from the sheathed heater 7 and the case 9 that are heating elements, so that the spiral spring 10 is completely fixed to the sheathed heater 7 or the case 9. Without being held, a part of the spiral spring 10 is held in a freely slidable state, so that it vibrates due to a flow force and a spring force received from the flow, so that an effect of peeling off the scale can be obtained.

  Furthermore, when using it in an area where the scale component of tap water is small or an area where the tap water pressure is low, the spiral spring 10 as a separate member is removed so that the pressure loss of the spiral spring 10 is reduced so as to cause a low pressure loss. It is possible to prevent the scale from adhering by changing the shape or attaching the attachment place to a place where the flow velocity becomes slow, thereby increasing the low pressure loss and the flow velocity. Moreover, since the replacement at the time of abnormality is facilitated, the maintainability can be improved.

  In addition, since the spiral spring 10 is configured to have a gap with the sheathed heater 7 that is a heating element, the spiral spring 10 is not in direct contact with the sheathed heater 7, so that heat is transferred to the spiral spring 10. This makes it difficult to prevent thermal damage to the spiral spring 10 and to extend the life. Furthermore, since it becomes difficult for heat to be transferred to the spiral spring 10, even a material having low heat resistance such as resin can be used. Therefore, the spiral spring 10 can be manufactured from a material that is easy to process, and can be made lightweight. Note that it is not necessary to provide a gap between the spiral spring 10 and the sheathed heater 7 in the entire range. For example, there is no problem even if the spiral spring 10 and the sheathed heater 7 are partially in contact with each other. However, in that case, it is desirable to prevent the corrosion by making the spiral spring 10 non-metallic or using the same metal as the sheath material of the sheathed heater 7.

  In addition, since the spiral spring 10 is configured to have a gap between the case 9 and the inner wall of the case 9, heat from the sheathed heater 7 is hardly transmitted to the case 9 via the spiral spring 10. Thermal damage is less likely to occur and the life can be extended. Furthermore, since water tends to flow along the inner wall of the case 9 due to centrifugal force, the peeled scale flows along the inner wall of the case 9 and can be prevented from being caught on the spiral spring 10 and being deposited on the surface of the copper pipe 17 again. Long life can be achieved. Note that it is not necessary to provide a gap between the spiral spring 10 and the inner wall of the case 9 in the entire range. For example, there is no problem even if the spiral spring 10 and the inner wall of the case 9 partially contact each other.

  Further, the helical spring 10 can improve the assemblability by having a gap with both the sheathed heater 7 and the inner wall of the case 9.

  In addition, although the material of the sheath of the sheathed heater 7 was demonstrated with the copper pipe, other metal pipes, such as a SUS pipe, have the same effect. Although the spiral guide has been described as a spiral guide, the same applies to a metal spiral spring, a spiral wire having no spring property, or a resin equivalent shape. Further, when used in a sanitary washing apparatus, the flow rate is about 100 to 2000 mL / min. Therefore, the outer diameter of the copper pipe 17 is about φ3 to 20 mm, and the spiral pitch is preferably about 3 to 20 mm. The inner diameter of the case 9 can be set in a range of φ5 to 30 mm so that the flow velocity is increased. Further, when a spiral spring is used for the spiral guide, the spiral spring has a wire diameter of about 0.1 to 3 mm and is excellent in workability. In the present embodiment, the spiral spring 10 is used as the spiral guide, but the structure may be integrated with the case 9 and the sheathed heater 7. Moreover, it is good also as a structure which provides the helical spring 10 in a part of flow path, and reduces pressure loss further.

  In this embodiment, the spiral spring 10 is described as the spiral guide. However, the effect of reducing the adhesion of the scale can be obtained even with a blade or a guide that converts a flow other than the spring into a spiral.

(Embodiment 2)
FIG. 6 is a sectional view of a heat exchanger according to the second embodiment of the present invention. The difference from FIG. 1 shown in the first embodiment is that the spiral spring 21 that is a spiral guide has a narrow pitch in the region where the surface temperature of the copper pipe 17 is equal to or higher than the predetermined temperature, and the others. This is the point that the pitch of the spiral springs 21 is widened in the region of. Others are the same as those of the first embodiment shown in FIG. 1, and the detailed description is omitted with the same numbers hidden.

  About the heat exchanger comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  As shown in FIG. 2, the sheathed heater 7 heats water by heating the coiled heating wire 18, but the temperature of the central portion is the highest due to thermal interference between the heating wires 18. have. In addition, the temperature of the water is higher on the downstream side due to heat exchange of the water, and the surface temperature of the copper pipe 17 increases with the water. For these reasons, the surface temperature of the copper pipe 17 rises in the area A shown in FIG. 6, that is, in the area centered slightly downstream from the center of the sheathed heater 7, and as a result, the area A This will increase the amount of scale attached.

  Therefore, in this embodiment, the pitch of the spiral springs 21 is narrowed in the region A where the surface temperature of the copper pipe 17 is equal to or higher than the predetermined temperature, and the pitch of the spiral springs 21 is widened in other regions. As a result, the apparent cross-sectional area 8a of the water flow 16 in the region A is reduced, so that the water flow rate in the region A can be increased, thereby preventing an increase in the surface temperature of the copper pipe 17. The amount of scale adhesion can be reduced. The predetermined temperature is desirably 60 ° C., more preferably 45 ° C. This is because when the temperature of the water containing scale exceeds about 60 ° C., the amount of scale adhesion tends to increase rapidly.

  That is, the pitch of the spiral springs 21 is narrowed in the region where the surface temperature of the copper pipe 17 is equal to or higher than the predetermined temperature, thereby reducing the scale adhesion in the high temperature portion where the scale adhesion is relatively likely to occur. In addition, the pressure loss of the flow path can be reduced as compared with the case where the pitch of the spiral springs 21 is reduced in the entire region.

  In this embodiment, for example, the pitch of the spiral spring 21 is changed to 10 mm when the surface temperature of the copper pipe 17 is less than 60 ° C., and the pitch is changed to 6 mm when the surface temperature is 60 ° C. or higher. However, for example, when the surface temperature of the copper pipe 17 is less than 45 ° C., the pitch of the spiral spring 21 is 10 mm, in the region of 45 ° C. or more and less than 60 ° C., the pitch is 8 mm, and in the region of 60 ° C. or more, the pitch is changed. A configuration in which the pitch is changed in multiple stages, such as 6 mm, may be used.

  In this embodiment, the spiral spring 21 is used as the spiral guide. However, the spiral spring 21 may be integrated with the case 9 and the sheathed heater 7.

(Embodiment 3)
FIG. 7 is a cross-sectional view of a heat exchanger according to the third embodiment of the present invention. The difference from FIG. 1 shown in the first embodiment is that the pitch Hb of the spiral spring 31 is narrowed on the downstream side and the pitch Ha of the spiral spring 31 is widened on the upstream side. Others are the same as those of the first embodiment shown in FIG. 1, and the detailed description is omitted with the same numbers hidden.

  About the heat exchanger comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  In the heat exchanger as shown in FIG. 7, the temperature of the water is higher toward the downstream side due to the heat exchange of the water, and the surface temperature of the copper pipe becomes higher together with the water. However, since the pitch of the spiral spring 31 on the downstream side is narrowed, the apparent flow path cross-sectional area is narrower on the downstream side 8c than on the upstream side 8b, and the water flow 16 flow rate can be increased. In addition to being able to reduce the scale adhesion on the downstream side, where scale adhesion is relatively likely to occur, the pitch of the spiral spring 31 is widened on the upstream side. Road pressure loss can be reduced.

  FIG. 8 shows a configuration in which the pitch of the spiral spring 41 is gradually narrowed from the upstream side to the downstream side of the flow path. Therefore, the flow velocity continuously increases as going downstream where scale adhesion is likely to occur, and scale adhesion can be effectively reduced, and the pressure in the flow path can be reduced rather than the pitch of the entire spiral spring 41 being narrowed. Loss can be reduced. Moreover, since the pitch of the spiral spring 41 is continuously narrowed, the flow velocity can be smoothly increased from upstream to downstream.

  Further, FIG. 9 shows a configuration in which the pitch of the spiral spring 51 is intermittently narrowed from the upstream side to the downstream side of the flow path. Therefore, the flow velocity increases intermittently as it goes downstream, where scale adhesion is likely to occur, and scale adhesion can be effectively reduced. Can be reduced. Further, the manufacturing becomes easier as compared with the case where the pitch of the spiral spring is continuously narrowed. In this embodiment, the pitch of one spiral spring is changed. However, a configuration using a plurality of springs having different pitches may be used.

  In this embodiment, the spiral springs 31, 41, 51 are used as the spiral guides, but may be configured integrally with the case 9 and the sheathed heater 7.

(Embodiment 4)
FIG. 10 is a sectional view showing a sanitary washing device according to a fourth embodiment of the present invention. And it is the structure of the sanitary washing apparatus using the heat exchanger in any one of Embodiment 1-3, and the heating toilet seat 62 and the sanitary washing apparatus main body 63 are installed on the toilet bowl 61. FIG. And the heat exchanger 64 is provided in the sanitary washing apparatus main body 63, and the heat-exchanged hot water is ejected from the washing nozzle 65 to wash the local part of the human body 66. And in the sanitary washing apparatus main body, the shut-off valve 67 and the flow control device 68 are provided as main parts. Other parts such as the control board are omitted.

  In such a sanitary washing device, the heat exchanger 64 that is small and has little scale adhesion is incorporated in the sanitary washing device body 63, so that the size of the body can be reduced and the life of the heat exchanger can be extended and the sanitary washing can be performed. The service life of the apparatus can be extended, and the washing nozzle 65 and the like as well as the heat exchanger 64 are not clogged, so that a sanitary washing apparatus with stable operation can be obtained.

  In particular, by using a cylindrical small heat exchanger, the heat exchanger 64 can be installed in the lower part of the cleaning nozzle 65 which has become a dead space due to the installation of the expanding and contracting cleaning nozzle 65, and the entire main body can be reduced in size. Can contribute to

  In addition, since the scale is difficult to adhere to the heat exchanger, the outflow of the scale is suppressed, so that the scale is not clogged with the cleaning nozzle 65, the flow rate control device 68, etc., and it can be used for a long time with stable operation. is there.

  As described above, the heat exchanger according to the present invention and the sanitary washing device using the heat exchanger apparently include a spiral guide that converts the flow direction into the swirl direction in the flow path provided on the outer periphery of the heating element. It is possible to reduce the cross-sectional area of the flow path, and by increasing the flow rate of the water flowing through the flow path, the boundary layer between the heating element and water can be narrowed and the surface temperature of the heating element can be lowered. The amount of adhesion such as can be reduced. As a result, it is possible to obtain a heat exchanger that is small, has high efficiency, and has a long life. And the sanitary washing device using it can realize downsizing of the sanitary washing device body by downsizing the heat exchanger, can be easily installed in a narrow toilet space, has a long life, and It can be set as the apparatus which does not produce malfunctioning easily.

Sectional drawing of the heat exchanger in Embodiment 1 of this invention Cross section of the heat exchanger Cross section of the heat exchanger Flow distribution diagram in heat exchanger Flow distribution diagram in heat exchanger Sectional drawing of the heat exchanger in Embodiment 2 of this invention Sectional drawing of the heat exchanger in Embodiment 3 of this invention Sectional drawing of the heat exchanger which shows the other Example of the same heat exchanger Sectional drawing of the heat exchanger which shows the other Example of the same heat exchanger Sectional drawing of the sanitary washing apparatus in Embodiment 4 of this invention. Cross-sectional view of a conventional sanitary washing device

7 Sheathed heater (heating element)
8 Flow path 9 Case 10 Spiral spring (spiral guide)
63 Sanitary washing device 64 Heat exchanger

Claims (7)

A flow path provided on the outer periphery of the heating element;
A case constituting the flow path;
A spiral guide for converting the flow direction into the swirl direction in the flow path ,
The spiral guide is a heat exchanger that is slidably held on at least the surface of the heating element so as to vibrate due to the flow force in the flow path . The heat exchanger according to claim 1, wherein the spiral guide has a non-uniform pitch. The heat exchanger according to claim 2, wherein the spiral guide narrows the pitch in a region where the surface temperature of the heating element is equal to or higher than a predetermined temperature. The heat exchanger according to claim 2 or 3, wherein the spiral guide narrows the pitch on the downstream side of the flow path. The heat exchanger according to any one of claims 2 to 4, wherein the spiral guide continuously reduces the pitch toward the downstream side of the flow path. The heat exchanger according to any one of claims 2 to 4, wherein the spiral guide intermittently narrows the pitch toward the downstream side of the flow path. A sanitary washing device comprising the heat exchanger according to claim 1.

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