WO2012144122A1

WO2012144122A1 - Hygienic cleaning device

Info

Publication number: WO2012144122A1
Application number: PCT/JP2012/001522
Authority: WO
Inventors: 良一古閑
Original assignee: パナソニック株式会社
Priority date: 2011-04-22
Filing date: 2012-03-06
Publication date: 2012-10-26
Also published as: KR20120137476A; TW201242561A; CN102859086B; CN102859086A; TWI504370B; KR101399717B1

Abstract

This hygienic cleaning device (1) is provided with a nozzle (7), a water supply path (9), and a heat exchanger (10). The heat exchanger (10) has a casing (23), a flat plate-shaped heater (20), and a flow path space (25). The flow path space is formed in such a manner that the width of gaps measured on the inlet section side is less than the width of the gaps measured on the outlet section side.

Description

Sanitary washing device

The present invention relates to a sanitary washing apparatus, and more particularly, to a sanitary washing apparatus having a nozzle that ejects hot water.

Conventionally, a sanitary washing device that ejects hot water from a nozzle is known.

For example, a flat heater is accommodated vertically in a rectangular parallelepiped casing having a small thickness. Two flow paths are formed along each of the heat transfer surfaces of the flat heater so as to meander upward in the horizontal direction. While the flat heater is driven, the washing water flows along each flow path, and the temperature is raised to an appropriate temperature (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-220876

In the conventional example, there is a possibility that a portion where the washing water stays or the bubbles stagnate in the meandering flow path. In such a portion where the washing water stays, the washing water boils locally. In this local boiling portion, the calcium component contained in the washing water adheres to the surface of the flat heater, and a scale is generated. The heat transfer to the washing water is hindered by the scale, resulting in a local high temperature of the flat heater. Furthermore, the generation of scale is promoted, and the flow path resistance of the washing water is increased in the accumulated scale. Thereby, there is a possibility that a necessary flow rate of cleaning water cannot be secured.

Also, in the part where the bubbles stagnate, the above problems occur due to the retention of washing water and the local high temperature of the flat heater.

Furthermore, when the flat heater becomes locally hot due to the scale, a temperature difference occurs in the flat heater. Due to the thermal stress due to this temperature difference, in a flat plate heater using ceramics as a heating element, the flat plate heater is cracked or broken, and the flat plate heater fails.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a sanitary washing apparatus capable of ensuring a necessary flow rate of washing water and preventing failure.

A sanitary washing device according to an aspect of the present invention has a nozzle, an upstream end to be connected to a water supply source, and a water supply path whose downstream end is connected to the nozzle, and heat exchange provided in the water supply path The heat exchanger includes an inflow portion, an outflow portion located above the inflow portion, a lower end portion communicated with the inflow portion, an upper end portion communicated with the outflow portion, and a vertical direction. A plate-like heater housing space formed to extend to the heater, and heat transfer that is accommodated in the heater housing space of the casing so as to extend in the vertical direction and faces the main surface of the heater housing space A flat plate-like heater including a surface, and a flow path space formed in a gap between the heat transfer surface and the main surface of the heater housing space, and the flow path space is formed on the inflow portion side. The width of the gap is smaller than the width of the gap on the outflow portion side. It is formed in so that.

The present invention has the above-described configuration, and has an effect that it is possible to provide a sanitary washing device that can secure a necessary flow rate of washing water and prevent failure.

The above object, other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.

It is a perspective view which shows the state with which the sanitary washing apparatus which concerns on Embodiment 2 of this invention was mounted | worn with the toilet bowl. It is a top view which shows the front of the heat exchanger mounted in the sanitary washing apparatus of FIG. It is a top view which shows the right main surface of the heat exchanger of FIG. FIG. 3 is a cross-sectional view showing the heat exchanger cut along line AA in FIG. 2. FIG. 4 is a longitudinal sectional view showing a heat exchanger cut along a line BB in FIG. 3. It is an enlarged view of the area | region of C of FIG. It is a top view which shows the heating wire formed in the heat exchanger of FIG. It is a top view which shows the modification of the heating wire formed in the heat exchanger of FIG. It is a schematic diagram which shows the main structures of the sanitary washing apparatus which concerns on Embodiment 1 of this invention. It is a cross-sectional view which shows the heat exchanger mounted in the sanitary washing apparatus of FIG. It is a schematic diagram which shows the main structures of the sanitary washing apparatus which concerns on the modification of this invention.

(Knowledge that became the basis of the present invention)
The present inventors examined a heat exchanger in which a flow path was formed along both heat transfer surfaces of a flat heater.

Generally, heat exchangers are designed on the assumption that the heat transfer amounts on both heat transfer surfaces to the wash water are approximately the same. If there is a large difference in the amount of heat transfer on both sides, a local boiling phenomenon may occur in the flow path on one side, and bubbles may be generated. Such bubbles increase the flow resistance of the washing water in the flow path, the flow rate balance in both flow paths is lost, and the difference in the amount of heat transfer becomes larger.

Also, a temperature sensor such as a thermistor may be provided near the water outlet of the heat exchanger. In this case, if bubbles grow large and adhere to the temperature sensor, the temperature sensor cannot contact the cleaning water. For this reason, a temperature sensor cannot detect appropriately.

Furthermore, when the bubbles adhere to the heat transfer surface and grow large, the bubbles are interposed between the heat transfer surface and the washing water, and both are dissociated. In this case, it becomes difficult to transfer heat from the heat transfer surface to the washing water, and the temperature of the heat transfer surface increases greatly. The temperature difference between the heat transfer surface to which bubbles are attached and the opposite heat transfer surface is increased. Due to the thermal stress, the flat heater is deformed and the life of the heat exchanger is shortened.

The most dominant factor that the scale adheres 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 of the heat transfer surface is determined to be 100 ° C. or lower, preferably 80 ° C. or lower, at which boiling occurs. In addition, the set temperature of the heat transfer surface is appropriately determined by the scale concentration of tap water, the required durability time of the heater, and the like. If a part of the heat transfer surface exceeds the set temperature, the scale adheres to that part and the scale becomes an obstacle to heat transfer. In order to avoid this, the area of the heat transfer surface may be increased. However, this is not preferable because it increases the cost of the heat exchanger. It is also conceivable to set the watt density or heat transfer coefficient distribution of the flat heater so that the temperature of the heat transfer surface is substantially uniform as a whole. In this case, the size of the heat transfer surface is minimum, and the temperature of the heat transfer surface can be set to a set temperature or less, but the cost of the flat heater is increased.

It is also conceivable to further increase the speed of the washing water in order to suppress the generation of bubbles that cause scale and the like, or to promote the discharge of bubbles. In this case, the heat transfer rate from the heat transfer surface to the washing water is improved, and the size of the heat transfer surface can be reduced. However, generally, in a sanitary washing device used for a warm water washing toilet seat, the amount of water used per wash water is small. For this reason, the flow path must be made very thin to increase the flow rate of the washing water. Usually, the maximum value of the flow rate of cleaning water is about 500 cc / min. In order to further increase the flow rate with respect to this flow rate value, it is necessary to set the channel thickness within 0.5 mm. Thus, when the flow path thickness is very thin, local non-uniformity in the flow velocity tends to occur. Since the thickness of the flow path: 0.5 mm is smaller than the order of the thickness of the speed boundary layer: several mm, the speed boundary layer covers the entire flow path. Therefore, the velocity gradient changes depending on the channel thickness, and the non-uniform flow velocity is likely to occur due to the non-uniform channel thickness.

Also, the velocity boundary layer is a fluid layer where the velocity is zero on the heat transfer surface and the velocity changes rapidly. For this reason, the force which discharges the bubble on a heat-transfer surface from on a heat-transfer surface is weak. Further, when the channel thickness is small, the size of bubbles generated in the channel tends to be larger than the channel thickness. In this case, the foam is deformed corresponding to the thickness of the flow path, and a push-up force is generated by the surface tension of the foam, so that the foam is difficult to move. Therefore, bubbles stay in the flow path, and unevenness of the flow rate tends to be locally generated by the bubbles.

When this local non-uniform flow velocity occurs, the heat transfer surface temperature rises significantly locally in a flat watt heater with a high watt density such that the watt density is 30 W / cm 2 or more. Boiling occurs at this point, and bubbles are further generated. For this reason, the non-uniformity of the flow is promoted, and the heat transfer surface is burned out.

∙ Since the pressure loss increases, it is difficult to greatly increase the flow rate of the washing water. Moreover, since the speed becomes non-uniform, it is difficult to reduce the thickness of the flow path. Furthermore, if the flow path is meandered in the horizontal direction, the distance and time of the wash water flowing through the flow path is long and the cross-sectional area of the flow path is small. Therefore, a meandering flow path is also not preferable.

If a flat heater is used for the heat exchanger, the heat exchanger becomes compact and the heat transfer area can be easily increased. However, it was difficult to generate a uniform and fast flow along the heat transfer surface by forced convection. Moreover, in order to generate a fast flow along the heat transfer surface, as described above, if the thickness of the flow path is reduced, the flow tends to be non-uniform. For this reason, when a superheated part is produced partially, heat concentrates on this superheated part, the washing water of this part evaporates, and a bubble is produced. If the bubbles do not flow out, this part is further heated. As a result, when the bubbles become large and the heat transfer surface becomes extremely hot, the heater is destroyed.

Also, in order to form a thin and fast flow along the heat transfer surface, a method of providing a flat throttle portion at the inflow portion of the flow path is also conceivable. However, air or the like tends to accumulate in the throttle portion, and the bubbles make the flow non-uniform. Thus, there is a problem in providing a flat throttle portion at the inflow portion of the flow path.

In addition, air is contained in the fluid even in domestic water supply pipes. For this reason, it is necessary to smoothly discharge bubbles such as air without staying in the heat exchanger.

The present invention has been made based on the above findings.

A sanitary washing device according to an embodiment of the present invention has a nozzle, an upstream end to be connected to a water supply source, and a water supply path whose downstream end is connected to the nozzle, and heat exchange provided in the water supply path The heat exchanger includes an inflow portion, an outflow portion located above the inflow portion, a lower end portion communicated with the inflow portion, an upper end portion communicated with the outflow portion, and a vertical direction. A plate-like heater housing space formed to extend to the heater, and heat transfer that is accommodated in the heater housing space of the casing so as to extend in the vertical direction and faces the main surface of the heater housing space A flat plate-like heater including a surface, and a flow path space formed in a gap between the heat transfer surface and the main surface of the heater housing space, and the flow path space is formed on the inflow portion side. The width of the gap is smaller than the width of the gap on the outflow portion side. It is formed in so that.

In the sanitary washing device, the flat heater may be configured such that the heat generation density on the inflow portion side is larger than the heat generation density on the outflow portion side.

In the sanitary washing device, the flat heater includes a ceramic base and a heating wire formed by pattern printing on the ceramic base, and a cross-sectional area of the heating wire on the inflow portion side is the outflow It may be smaller than the cross-sectional area of the heating wire on the part side.

In the sanitary washing apparatus, the flat heater includes a ceramic base and a heating wire formed by pattern printing on the ceramic base, and an interval between the heating wires adjacent to each other on the inflow portion side is as follows. It may be larger than the interval between the heating wires adjacent to each other on the outflow portion side.

In the sanitary washing device, the heat exchanger further includes a water inlet, and a header portion formed between the water inlet and the inflow portion. A throttle channel that gradually narrows toward 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 denoted by the same reference symbols throughout all the drawings, and redundant description thereof is omitted.

Further, a state in which the heat exchanger 10 is placed vertically so that the heat transfer surfaces 20a and 20b of the flat heater 20 are in the vertical direction will be described. 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 20 a and 20 b of the flat heater 20. The Y direction indicates a direction orthogonal to both the Z direction and the X direction. Further, the cross-sectional area indicates an area in a plane perpendicular to the flow of the cleaning water.

(Embodiment 1)
FIG. 9 is a schematic diagram illustrating a main configuration of the sanitary washing device 1 according to the first embodiment.

The sanitary washing device 1 includes a nozzle 7, a water supply path 9 having an upstream end to be connected to the water supply source 8, and a downstream end connected to the nozzle 7, and a heat exchanger 10 provided in the water supply path 9. Prepare.

FIG. 10 is a cross-sectional view showing the heat exchanger 10 mounted on the sanitary washing device 1 of FIG.

The heat exchanger 10 has an inflow portion 10a, an outflow portion 10b positioned above the inflow portion 10a, a lower end portion that communicates with the inflow portion 10a, an upper end portion that communicates with the outflow portion 10b, and extends vertically. A casing 23 including a plate-shaped heater housing space 23c formed therein, and is accommodated in the heater housing space 23c of the casing 23 so as to extend in the vertical direction, and is opposed to the

main surfaces

30a and 40a of the heater housing space 23c. And a flow path space 25 formed in a gap between the heat transfer surfaces 20a and 20b and the

main surfaces

30a and 40a of the heater accommodating space 23c. The flow path space 25 is formed such that the width of the gap on the inflow portion 10a side is smaller than the width of the gap on the outflow portion 10b side. Here, the “vertical direction” is a concept including both the vertical direction and the direction intersecting the vertical direction. The “heater accommodating space” means a space including a region where the heater is present and a space in contact with the region, assuming that the heater is removed from the casing. In other words, the “flow path space” is a flow path formed so as to guide a fluid (here, water) along the pair of heat transfer surfaces of the flat heater in the casing.

In the sanitary washing device 1 having the above configuration, the washing water flows from the water supply source 8 through the water supply passage 9. Wash water flows into the heat exchanger 10 in the water supply channel 9 and is heated here. The wash water that has reached a high temperature flows out of the heat exchanger 10 and is supplied to the nozzle 7. Thereby, hot water is ejected from the nozzle 7.

Further, in the heat exchanger 10, the washing water flows into the heater accommodating space 23c of the casing 23 from the inflow portion 10a. The washing water enters between the planar

main surfaces

30 a and 40 a of the heater housing space 23 c and the heat transfer surfaces 20 a and 20 b of the flat heater 20 and passes through the flow path space 25. At this time, the washing water is heated by the heat transfer surfaces 20a and 20b, and the temperature rises.

In the flow path space 25, the width of the gap on the inflow portion 10a side is smaller than the width of the gap on the outflow portion 10b side. For this reason, the cleaning water flowing through the flow path space 25 is accelerated in forced convection on the inflow portion 10a side. Here, the velocity gradient of the boundary layer between the heat transfer surfaces 20a and 20b and the washing water increases, and the heat transfer coefficient increases. Heat is applied to the washing water from the heat transfer surfaces 20a and 20b, the temperature of the heat transfer surfaces 20a and 20b is low, and scales are prevented from adhering to the heat transfer surfaces 20a and 20b.

Wash water flows from the inflow portion 10a side to the outflow portion 10b side by forced convection. The washing water is further heated by the heat transfer surfaces 20a and 20b on the outflow portion 10b side. Thereby, the air mixed in the cleaning water expands and bubbles are generated. Since the width of the gap on the outflow portion 10b side is large, the bubbles exit to the outflow portion 10b without staying in the flow path space 25.

Further, the temperature of the washing water rises and the density thereof decreases, so that an upward flow of natural convection occurs, and the washing water flows to the outflow portion 10b. Since the width of the gap on the outflow portion 10b side is large, bubbles are easily removed by the upward flow of natural convection, and the heat transfer rate from the

heat transfer surfaces

20a, 20b to the washing water is improved.

According to the sanitary washing device 1 having the above-described configuration, the bubbles are smoothly discharged, so that heat exchange between the washing water and the heat transfer surfaces 20a and 20b is stably performed without being inhibited by the bubbles.

Also, it is reduced that the cleaning water stays in a part due to bubbles and the scale is locally generated. For this reason, since the washing water flows smoothly without the scale narrowing the flow path space 25, it is possible to secure the washing water with a necessary flow rate.

Furthermore, bubbles do not adhere to the heat transfer surfaces 20a and 20b, and this portion is heated to prevent a temperature difference between the heat transfer surfaces 20a and 20b. Thereby, it can prevent that the heat-

transfer surfaces

20a and 20b are not deform | transformed or damaged by the thermal stress by a temperature difference, and the flat heater 20 fails.

(Embodiment 2)
[Configuration of sanitary washing equipment]
FIG. 1 shows a toilet in which a sanitary washing device 1 according to Embodiment 2 is attached to a toilet bowl 2.

The sanitary washing device 1 is disposed on the upper surface of the toilet bowl 2. The sanitary washing device 1 includes a main body part 3, a toilet seat part 4, a toilet lid part 5, and an operation part 6.

The main body 3 is disposed on the rear side of the toilet seat 4, that is, on the rear side as viewed from the seated user. The main body 3 is a horizontally long casing 3a and houses the water supply passage 9 and the heat exchanger 10 shown in FIG. In addition to this, the main body unit 3 houses a cleaning unit, a drying unit, a control unit for controlling these operations, and the like (not shown).

The water supply channel 9 introduces tap water (fluid, liquid, washing water) into the nozzle 7 through the heat exchanger 10 from a water supply facility (water supply source 8) attached to the building where the toilet 2 is installed. When the user operates the operation unit 6 to perform a predetermined input, the cleaning unit is driven. Washing water is warmed by the heat exchanger 10, and the hot water is discharged from the nozzle 7 in a shower shape toward the opening of the toilet 2.

[Configuration of heat exchanger]
FIG. 2 is a plan view showing the front of the heat exchanger 10. FIG. 3 is a plan view showing the right main surface of the heat exchanger 10. FIG. 4 is a cross-sectional view showing the heat exchanger 10 cut along the line AA in FIG. FIG. 5 is a longitudinal sectional view showing the heat exchanger 10 cut along the line BB in FIG. 6 is an enlarged view of a region C in FIG.

The heat exchanger 10 has a small thickness in the Y direction and a rectangular shape in the XZ direction. As shown in FIG. 4, the heat exchanger 10 includes a flat heater 20, a first flow path forming member 21, and a second flow path forming member 22.

A casing 23 is formed by the first flow path forming member 21 and the second flow path forming member 22. The first flow path forming member 21 and the second flow path forming member 22 are each formed of, for example, a reinforced ABS resin obtained by compounding a glass fiber with an ABS resin.

The first flow path forming member 21 is disposed on the first heat transfer surface 20a side of the flat heater 20. The first flow path forming member 21 includes a base portion 30 and a shelf step portion 31. The base portion 30 includes a base surface (main surface) 30a. The base surface 30a has a planar shape and faces the first heat transfer surface 20a. In the shelf step portion 31, the thickness of the base portion 30 in the Y direction changes. The thickness of the base 30 on the outflow part 10 b side from the shelf step part 31 is smaller than the inflow part 10 a side from the shelf step part 31. For this reason, the base surface 30a on the inflow portion 10a side from the shelf step portion 31 is closer to the first heat transfer surface 20a than the base surface 30a on the outflow portion 10b side. The width between the base surface 30a on the inflow portion 10a side and the first heat transfer surface 20a is narrower than the width between the base surface 30a on the outflow portion 10b side and the first heat transfer surface 20a.

The first flow path forming member 21 is provided with a wall-like flange portion 32 around the entire periphery of the base portion 30. An engagement groove 33 is formed at the distal end of the flange portion 32, and the engagement groove 33 is formed along the entire circumference of the flange portion 32.

The second flow path forming member 22 is disposed on the second heat transfer surface 20 b side of the flat heater 20. The second flow path forming member 22 includes a base portion 40 and a shelf step portion 41. The base portion 40 includes a base surface (main surface) 40a. The base surface 40a has a planar shape and faces the second heat transfer surface 20b. In the shelf step portion 41, the thickness of the base portion 40 in the Y direction changes. The thickness of the base portion 40 on the outflow portion 10b side from the shelf step portion 41 is smaller than the shelf step portion 41 on the inflow portion 10a side. For this reason, the base surface 40a on the inflow portion side from the shelf step portion 41 is closer to the second heat transfer surface 20b than the base surface 40a on the outflow portion 10b side. The width between the base surface 40a on the inflow portion 10a side and the second heat transfer surface 20b is narrower than the width between the base surface 40a on the outflow portion 10b side and the second heat transfer surface 20b.

The second flow path forming member 22 is provided with a wall-like flange portion 42 around the entire periphery of the base portion 40. The flange part 42 protrudes toward the opposite side of the base surface 40a. And the front-end | tip part of the flange part 42 is return | folded to the base surface 40a side. An engagement protrusion 43 is provided at the tip of the tip, and the engagement protrusion 43 is formed over the entire circumference of the flange portion 42.

The flange portion 42 of the second flow path forming member 22 enters the flange portion 32 of the first flow path forming member 21, and the engaging protrusion of the second flow path forming member 22 enters the engaging groove 33 of the first flow path forming member 21. 43 fits. For example, the engagement protrusion 43 is fixed to the engagement groove 33 by ultrasonic welding. Thereby, the 1st flow path formation member 21 and the 2nd flow path formation member 22 are watertightly joined, and the casing 23 is formed.

The casing 23 has two side surfaces, two main surfaces, a top surface, and a bottom surface, and includes a substantially rectangular hollow portion surrounded by these. This substantially rectangular hollow portion constitutes a plate-shaped heater accommodating space 23c. The heater housing space 23c extends in the vertical 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 outflow portion 10b. Of the two side surfaces in the YZ direction, the water inlet 23a and the water outlet 23b open on one side. The opening of the water outlet 23b becomes the outflow part 10b. The water inlet 23a is provided at one end lower portion of the side surface, and is connected to the upstream end of the water supply channel 9 (FIG. 9). The water outlet 23b is provided at the upper end of the side surface and is connected to the downstream end of the water supply channel 9 (FIG. 9). Two main surfaces in the XZ direction are formed by

base surfaces

30a and 40a, respectively. The top surface faces the upper end of the flat heater 20. The top surface is inclined so that the gap between the top surface and the upper end of the flat heater 20 becomes wider as it approaches the water outlet 23b. The bottom surface faces the lower end of the flat heater 20. The inflow portion 10a of the flow path space 25 opens on the top surface, and the inflow portion 10a extends in the X 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 first heat transfer surface 20a and the base surface 30a and a flow path between the second heat transfer surface 20b and the base surface 40a. These two flow paths are formed symmetrically on both sides of the flat heater 20. Each of the two channels has an inlet side channel 25a and an outlet side channel 25b. The inlet-side flow path 25a is provided on the side closer to the water inlet 23a below the shelf steps 31, 41. The outlet side flow path 25b is provided on the side closer to the water outlet 23b above the shelf steps 31, 41. The Y-axis direction thickness of the inlet-side channel 25a is smaller than the Y-axis direction thickness of the outlet-side channel 25b.

As shown in FIG. 6, the header part 45 is provided between the inflow part 10a of the flow path space 25 and the water inlet 23a, and extends in the X direction. The header part 45 includes a header part main flow path 45a and a header part throttle flow path 45b. The cross-sectional area in the XY direction of the header portion main flow passage 45a is wider than that of the header portion restriction flow passage 45b. That is, the channel cross-sectional area in the XY direction is orthogonal to the flow of cleaning water flowing from the water inlet 23a to the inflow portion 10a. The flow passage cross-sectional area of the header portion restriction flow passage 45b gradually decreases from the header portion main flow passage 45a toward the inflow portion 10a from the inflow portion 10a. The header throttle channel 45b has a crank shape. The header portion narrowing channel 45b includes a vertical portion 45bb, a horizontal portion 45bc, and a vertical portion 45bd. In the order of the vertical portion 45bb, the horizontal portion 45bc, and the vertical portion 45bd, the cross-sectional areas become smaller (that is, narrower).

The flat heater 20 is accommodated in the heater accommodating space 23c of the casing 23 and extends in the vertical direction. The flat heater 20 has a rectangular flat plate shape and includes first and second heat transfer surfaces 20a and 20b on both surfaces. The flat heater 20 includes a ceramic substrate 20k, a resistor pattern 20p, and electrodes (not shown). The temperature of the heat transfer surfaces 20a and 20b is prevented from being locally higher than a predetermined temperature. This predetermined temperature is generally set to 100 ° C. or lower, preferably 80 ° C. or lower, at which boiling occurs in the temperature of the heat transfer surfaces 20a and 20b. Further, the predetermined temperature is appropriately determined depending on the scale concentration of tap water, the required durability time of the heater, and the like.

The resistor pattern 20p has a resistor printed on the ceramic substrate 20k. The resistor pattern 20p forms a heating wire (heater wire) and generates heat when energized from the electrodes. As shown in FIG. 7, the heater wire extends long in the X direction and spreads upward in the Z direction while meandering. The heater wire width 20s in the inlet-side channel 25a is narrower than the heater wire width 20s in the outlet-side channel 25b, and the heater wire has a smaller cross-sectional area. The smaller the heater wire width 20s and the smaller the heater wire cross-sectional area, the greater the resistance value of the heater wire. Therefore, the resistance value of the heater wire in the inlet side channel 25a is higher than the resistance value of the heater wire in the outlet side channel 25b. Thus, the heat generation density in the resistor pattern 20p in the inlet-side flow path 25a is higher than the heat generation density in the resistor pattern 20p in the outlet-side flow path 25b.

[Flow of cleaning water in sanitary cleaning equipment]
As shown in FIG. 9, when the electromagnetic valve is opened, the washing water flows from the water supply pipe of the water supply source 8 to the water supply passage 9 through the branch tap. As shown in FIGS. 3 and 4, the wash water flows into the casing 23 from the water supply channel 9 through the water inlet 23a.

As shown in FIG. 4 to FIG. 6, the cleaning water enters the header part main flow path 45a of the header part 45. Since the cross-sectional area of the header section throttle flow path 45b is much smaller than the cross-sectional area of the header section main flow path 45a, the resistance from the header section main flow path 45a to the header section throttle flow path 45b is in the X direction of the header section main flow path 45a. Greater than the resistance. Therefore, most of the washing water flows in the X direction of the header part main flow path 45a, and the washing water uniformly fills the header part main flow path 45a. Then, the washing water flows from the header part main flow path 45a to the header part throttle flow path 45b. Since the flow path cross-sectional area of the header portion narrowing flow path 45b is gradually narrowed, the flow of cleaning water becomes gradually faster. Further, there is no place where air stays in the header throttle channel 45b. For this reason, even if air is mixed in the washing water, the air is carried toward the inflow portion 10a without accumulating. When the washing water flows from the inflow portion 10a into the inlet-side flow path 25a, the bubbles rise smoothly by buoyancy along the flow path space 25 in the vertical direction. Further, the bubbles flow to the outflow portion 10b along the top surface of the casing 23 that increases toward the outflow portion 10b. And a bubble is discharged | emitted outside through the water outlet 23b from the outflow part 10b.

As shown in FIG. 4, the washing water flows from the inflow portion 10 a into the inlet side flow path 25 a of the flow path space 25. In the inlet side channel 25a, which is a region where the channel thickness is thin, the flow rate of the cleaning water is fast. For this reason, the velocity gradient of the boundary layer between each

heat transfer surface

20a, 20b of the flat heater 20 and the cleaning water is large, and the heat transfer coefficient between each

heat transfer surface

20a, 20b and the cleaning water is large. Moreover, in each of the heat transfer surfaces 20a and 20b, the heat generation density in the resistor pattern 20p in the inlet-side flow path 25a is high. Therefore, the washing water is heated by the heat transfer surfaces 20a and 20b and becomes high temperature, and its density is reduced. As a result, the washing water rises and flows from the inlet side channel 25a into the outlet side channel 25b.

In addition, since the heat generation density in the resistor pattern 20p in the inlet-side channel 25a is high, the temperature of each

heat transfer surface

20a, 20b tends to increase. However, since the temperature of the cleaning water in the inlet-side flow path 25a is low, the subcool (degree of cooling with respect to the boiling temperature of water) increases and the cleaning water takes a lot of heat from the heat transfer surfaces 20a and 20b. Furthermore, 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 washing water does not have such a high heat transfer rate that the local boiling phenomenon occurs.

In the outlet side channel 25b, in addition to forced convection in the inlet side channel 25a, natural convection also occurs due to the difference in density. As a result, the cleaning water rises along the heat transfer surfaces 20a and 20b. Since this wash water is heated in the inlet side flow path 25a, the temperature is high. The heat taken from each

heat transfer surface

20a, 20b by this washing water is small, and the subcool value is small. For this reason, the temperature of each heat-

transfer surface

20a, 20b in the exit side flow path 25b tends to rise. However, since the heat generation density in the outlet-side channel 25b is small, the temperature of the cleaning water gradually increases as it approaches the water outlet 23b, but no sudden boiling occurs. This prevents the scale from adhering to a part of each

heat transfer surface

20a, 20b.

Further, even if bubbles are generated on the heat transfer surfaces 20a and 20b, the bubbles rise through the outlet side channel 25b having a thick channel in the outlet side channel 25b. The bubbles are discharged from the water outlet 23b.

The washing water having such a high temperature flows into the water supply channel 9 from the outlet 23b. The temperature of the wash water is adjusted by a tank (not shown) or the like. When the solenoid valve is opened, warm washing water is discharged from the nozzle 7.

[effect]
The flow rate is gradually increased by the header throttle channel 45b whose cross-sectional area is gradually narrowed. For this reason, even when air is mixed in the water supply pipe, the bubbles are pushed out downstream from the header portion 45 and the flow path space 25 before the bubbles grow large. Thereby, the flow of the cleaning water on the heat transfer surfaces 20a and 20b becomes non-uniform due to the bubbles, and the heat transfer surfaces 20a and 20b are prevented from being locally overheated. Therefore, the scale is prevented from locally attaching to the heat transfer surfaces 20a and 20b and narrowing the flow path. Thereby, a required flow rate is ensured. Further, the flat heater 20 is prevented from being damaged by thermal stress due to the temperature difference between the heat transfer surfaces 20a and 20b due to the scale.

Further, since the header portion restricting passage 45b has a crank shape, the passage in the header portion restricting passage 45b becomes longer. For this reason, even if the cross-sectional area in the header throttle channel 45b is slightly increased, it is possible to ensure channel resistance in the header throttle channel 45b. As a result, the cleaning water can uniformly flow into the header throttle channel 45b over the entire length of the header main channel 45a.

A uniform and fast flow of cleaning water along the heat transfer surfaces 20a and 20b is formed in the flow path space 25 by the header throttle flow path 45b. Thereby, the heat transfer rate between each

heat transfer surface

20a, 20b and the washing water is increased. For this reason, washing water can be heated efficiently. Moreover, it can suppress that the temperature of each heat-

transfer surface

20a, 20b is low, and a scale adheres to each heat-

transfer surface

20a, 20b. In addition, bubbles generated on the heat transfer surfaces 20a and 20b are easily removed, and the occurrence of local scales and damage to the flat heater 20 due to thermal stress are prevented, and the heat transfer surfaces 20a and 20b and cleaning water Thus, stable heat exchange is possible without hindering the heat exchange.

In particular, the inlet-side channel 25a is close to the header throttle channel 45b and has a small channel thickness. For this reason, in the inlet side flow path 25a, the quick flow from the header part throttle flow path 45b is maintained. Therefore, the velocity gradient in the boundary layer between each

heat transfer surface

20a, 20b and the wash water is large, and the heat transfer coefficient due to forced convection between each

heat transfer surface

20a, 20b and the wash water is large. The washing water is efficiently heated and the flat heater 20 is prevented from being damaged.

Furthermore, since the heat generation density of each

heat transfer surface

20a, 20b in the outlet-side flow path 25b is small, the local boiling phenomenon is prevented, thereby preventing the flat heater 20 from being damaged.

Further, since the flat heater 20 heats the cleaning water by the heat transfer surfaces 20a and 20b on both the front and back surfaces, there is almost no heat dissipation loss. For this reason, the high heat efficiency of the heat exchanger 10 can be realized and the apparatus can be made compact.

Furthermore, also in the outlet side flow path 25b, the flat heater 20 is suppressed from being heated to such a high temperature that a local boiling phenomenon occurs, and local scale generation is prevented. For this reason, although a heat capacity is small compared with a metal, even if it uses a ceramic for the flat heater 20 if it is easy to break, the crack is prevented and the lifetime of the sanitary washing apparatus 1 is extended.

In addition, even if there is a large difference in the amount of heat transfer in each of the heat transfer surfaces 20a and 20b in the flat heater 20, and even if the cleaning water in one flow channel boils locally and bubbles are generated, It is discharged smoothly. Therefore, it is possible to prevent the flow resistance of the washing water from increasing, the flow rate balance between the two flow paths from being lost, and a large difference between the heat transfer amounts of the two flow paths from occurring.

Furthermore, even if a temperature sensor such as a thermistor is disposed in the vicinity of the outflow portion 10b of the flow path space 25, the temperature sensor can appropriately detect the temperature. In other words, the bubbles do not become large by discharging the bubbles. Thus, a situation is avoided in which large bubbles are attached to the temperature sensor, and the temperature sensor cannot contact the cleaning water due to the large bubbles and cannot detect the temperature of the cleaning water.

Further, the forced convection of the washing water and the discharge of the bubbles suppress the scale from adhering to the heat transfer surfaces 20a and 20b. Thereby, in order to avoid the heat transfer failure by a scale, it is not necessary to increase the area of the heat-

transfer surfaces

20a and 20b. Therefore, the cost increase of the sanitary washing device 1 can be prevented and the size can be reduced. further,
In addition, the sectional area of the header throttle channel 45b is gradually narrower, and the sectional area of the inlet-side channel 25a is narrower than that of the outlet-side channel 25b in the channel space 25. Thereby, even if it does not make flow path thickness thin, the uniform quick flow of the washing water along each heat-

transfer surface

20a, 20b is formed.

Further, forced convection is generated by the header restricting flow path 45b having a gradually reduced cross-sectional area and the inlet-side flow path 25a having a narrow cross-sectional area, and bubbles on the heat transfer surfaces 20a and 20b are quickly pushed upward. . In addition, even in the outlet side channel 25b having a large cross-sectional area, even a large bubble can easily move. Therefore, the bubbles are quickly discharged to the outside. Thereby, the flow of cleaning water becomes uniform.

Further, the heat generation density of each

heat transfer surface

20a, 20b is such that the outlet side flow path 25b is smaller than the inlet side flow path 25a. On the other hand, the flow rate of the washing water is larger in the inlet side channel 25a than in the outlet side channel 25b. For this reason, as for the heat flux of each heat-

transfer surface

20a, 20b, the inlet side flow path 25a is higher than the outlet side flow path 25b. Thereby, the temperature of the heat transfer surfaces 20a and 20b can be made uniform, and local adhesion of scale can be suppressed.

[Other examples]
In the second embodiment, as shown in FIG. 7, the heater wire width 20s in the inlet-side channel 25a is formed to be narrower than the heater wire width 20s in the outlet-side channel 25b. However, as long as the heat generation density in the resistor pattern 20p in the inlet-side channel 25a is higher than the heat generation density in the resistor pattern 20p in the outlet-side channel 25b, the heater wire width is not limited to 20s.

For example, as shown in FIG. 8, in the resistor pattern 20p, the interval 20h between the heater wires adjacent to each other in the inlet-side channel 25a is narrower than that in the outlet-side channel 25b. Thereby, the heat generation density in the resistor pattern 20p in the inlet-side flow path 25a is higher than the heat generation density in the resistor pattern 20p in the outlet-side flow path 25b.

In the second embodiment, the header throttle channel 45b has a substantially crank shape, and its channel cross-sectional area is gradually narrowed. The shape of the header throttle channel 45b is not limited to a substantially crank. For example, the header portion restriction channel may be formed by a substantially “<”-shaped cross section formed by two sides of the vertical portion 45bb and the horizontal portion 45bc shown in FIG. Moreover, it is not limited to what a flow-path cross-sectional area is narrowed in steps. For example, as shown in FIG. 11, the header restricting flow path may be formed with a triangular cross section whose interval becomes narrower upward. In this case, the flow path cross-sectional area is narrowed gradually.

Furthermore, in the second embodiment, the thickness of the

base portions

30 and 40 in the Y direction is changed stepwise by the shelf steps 31 and 41 in the

members

21 and 22. Thereby, two

flow paths

25 a and 25 b having different cross-sectional areas are provided in the flow path space 25. On the other hand, as shown in FIG. 11, each

member

21 and 22 may be formed so that the thickness of the

base parts

30 and 40 in the Y direction gradually changes. In this case, the channel space 25 is provided with one channel whose cross-sectional area gradually changes.

In addition, all the above embodiments may 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 present invention are apparent to persons skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

The sanitary washing apparatus of the present invention is useful as a sanitary washing apparatus that can secure a necessary flow rate of washing water and prevent failure.

DESCRIPTION OF SYMBOLS 1 Sanitary washing device 7 Nozzle 8 Water supply source 9 Water supply path 10 Heat exchanger

10a Inflow part

10b Outflow part 20 Flat heater 20a First heat transfer surface (heat transfer surface)
20b Second heat transfer surface (heat transfer surface)
20k ceramic substrate 20p pattern (heating wire)
23 Casing 23a Water inlet 25 Channel space 30a Base surface (main surface)
40a Base surface (main surface)
45 Header section 45a Header section main flow path (main flow path)
45b Restriction flow path (throttle flow path) for header section

Claims

A nozzle, an upstream end to be connected to a water supply source, a downstream water supply path connected to the nozzle, and a heat exchanger provided in the water supply path,
The heat exchanger is
An inflow portion, an outflow portion located above the inflow portion, a lower end portion communicates with the inflow portion, an upper end portion communicates with the outflow portion, and is formed so as to extend vertically. A casing including a housing space;
A flat plate-like heater that is accommodated in the heater accommodation space of the casing so as to extend in the vertical direction and includes a heat transfer surface facing the main surface of the heater accommodation space;
A flow path space formed in a gap between the heat transfer surface and the main surface of the heater housing space, wherein the flow path space has a width of the gap on the inflow portion side that is on the outflow portion side. The sanitary washing device is formed to be smaller than the width of the gap.
The sanitary washing device according to claim 1, wherein the flat heater is configured such that a heat generation density on the inflow portion side is larger than a heat generation density on the outflow portion side.
The flat heater has a ceramic base and a heating wire formed by pattern printing on the ceramic base,
The sanitary washing device according to claim 1 or 2, wherein a cross-sectional area of the heating wire on the inflow portion side is smaller than a cross-sectional area of the heating wire on the outflow portion side.
The flat heater has a ceramic base and a heating wire formed by pattern printing on the ceramic base,
The sanitary washing device according to claim 1 or 2, wherein an interval between the heating wires adjacent to each other on the inflow portion side is larger than an interval between the heating wires adjacent to each other on the outflow portion side.
The heat exchanger further includes a water inlet, and a header portion formed between the water inlet and the inflow portion,
The sanitary washing device according to any one of claims 1 to 4, wherein the header section includes a main channel and a throttle channel that gradually narrows from the main channel toward the inflow portion.