JP3702454B2 - Local boiling prevention structure in hot water supply circuit - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a local boiling prevention structure in a hot water supply circuit in a so-called one-can two-circuit type hot water heater with a hot water bath provided with a heat exchanger for hot water supply and a heat exchanger for bath in one can body.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a so-called one-can two-circuit bath water heater with a hot water supply heat exchanger and a bath heat exchanger provided in one can body is known.
This one-can two-circuit type water heater with a bath kettle has one heating heat source, and heats both the hot water supply heat exchanger and the bath heat exchanger with one heat source.
In the water heater with a single can and two-circuit bath pot, when the bath is used alone, that is, when only the circulation heating of the bath is performed, the hot water supply heat exchanger connected to the hot water supply circuit that is stopped is heated. The water staying in the heat exchanger for hot water supply may be heated to a boiling state.
In order to solve this problem and avoid a boiling state, a boiling thermistor provided in the hot water supply circuit detects an excessive rise in the hot water temperature in the hot water heat exchanger, and controls combustion on / off according to the detected temperature. Boiling avoidance methods are commonly used.
[0003]
[Problems to be solved by the invention]
However, in the boiling state avoidance method in which the combustion is turned on / off according to the excessive rise of the hot water temperature in the hot water supply heat exchanger when the conventional bath is used alone, the number of times of on / off of the combustion is large, or When the off-time is long, there is a problem that the bathing time becomes long.
[0004]
An object of the present invention is to provide a local boiling prevention structure in a hot water supply circuit capable of suppressing boiling in a heat exchanger and shortening the time for bathing.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a local boiling prevention structure in a hot water supply circuit according to the present invention comprises a reverse combustion type single can two circuit type hot water heater with a bath tub, an inlet side end of a hot water heat exchange pipe, and a hot water side end. A substantially shut-hat shape in which a water stop valve is provided in the middle of the bypass pipe, and a shut-off valve is provided that is closed except during bath heating single operation, and the valve body of the water stop valve is formed of a material having a specific gravity of 1 or more. The valve body protrudes upward at the center part, and a bottomed cylindrical part having an open lower end is formed, and an annular flange extending outward is formed at the periphery of the lower end opening part of the bottomed cylindrical part. A plurality of drainage slits are formed on the lower surface of the collar portion . In particular, the shape of a substantially silk hat made of a material with a specific gravity of 1 or more enables the valve body to be made of a material such as reinforced plastic with a specific gravity of 1 or more, increasing the strength of the valve body and improving durability. To do.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, a reverse combustion type single-can / two-circuit type hot water heater 1 with a hot water tank 1 includes a cylindrical can body (combustion chamber) 4 and a hot water supply heat exchange wound around the can body 4. A heat exchange pipe 3 for bath heating arranged in contact with the pipe 2, the heat exchange pipe 2 for hot water supply, a reverse combustion burner 5 that burns downwardly installed on the upper end opening side of the can body 4, and A fan 6 and an exhaust pipe 11 continuous with the lower end opening of the can 4 are provided, and the lower part of the hot water supply heat exchange pipe 2 and the bath heating heat exchange pipe 3 are provided with finned hot water supply heat exchange pipes 20 and fins. It is formed by a heat exchange tube 30 for bath heating.
[0007]
An inlet pipe 21 is connected to the upper end opening side (incoming water side) of the heat exchange pipe 2 for hot water supply, and a hot water outlet pipe 22 is connected to the lower end opening side (outlet side), and the upper end opening side of the heat exchange pipe 3 for bath heating. A bath return pipe 31 from the bathtub is connected to the (bath return side), and a bath return pipe 32 to the bathtub is connected to the lower end opening side (the bath going side).
Thereby, low temperature water flows in from the upper ends of both heat exchange tubes 2, 3, and heated high temperature water flows out from the lower ends of both heat exchange tubes 2, 3.
[0008]
A bypass pipe 9 having both ends connected to the upper end opening side (incoming water side) and the lower end opening side (outgoing water side) of the heat exchange pipe 2 for hot water supply is provided, and a water stop valve 10 is provided in the middle of the bypass pipe 9. Is provided.
[0009]
The operation will be described. When only the bath heating operation is performed and only the bath heating heat exchange pipe 3 is used alone, the hot water supply heat exchange pipe 2 is simultaneously heated by the burner 5 together with the bath heating heat exchange pipe 3. The water from the bathtub is circulated and heated in the heat exchange pipe 3 for bath heating, and the water staying in the heat exchange pipe 2 for hot water supply is simultaneously heated.
[0010]
At this time, the hot water supply heat exchange pipe 2 and the bypass pipe 9 whose both ends are connected to the upper end opening side and the lower end opening side of the hot water supply heat exchange pipe 2 (the water stop valve 10 is opened) are used. A circulation circuit of the heated water in the exchange pipe 2, that is, a natural convection circuit is formed.
In the circulation circuit, high-temperature water heated in the hot water supply heat exchange pipe 2 descends from the upper end of the hot water supply heat exchange pipe 2 in the bypass pipe 9, and hot water is supplied as low temperature water from the lower end of the hot water supply heat exchange pipe 2. Into the heat exchange pipe 2 for use.
[0011]
With this configuration, when only the bath heating operation is performed, the hot water in the hot water supply heat exchange pipe 2 is heated to reduce the specific gravity, move upward, and be cooled by heat exchange with the bath heating heat exchange pipe 3. This increases the specific gravity and moves downward through the bypass pipe 9. As described above, natural convection occurs in the hot water supply heat exchange pipe 2 and the bypass pipe 9, and therefore, the temperature rise of the high-temperature water in the hot water supply heat exchange pipe 2 is suppressed, local boiling is suppressed, and combustion is turned on. -The number of off times can be reduced, and the bath memorial ability can be improved.
In addition, since the bypass pipe 9 is securely closed and all of the water introduced from the water inlet pipe 21 passes through the hot water supply heat exchange pipe 2, stable heat exchange is possible, and the hot water discharge characteristic is also stable. Moreover, the hot water temperature at the time of re-bathing is easy to be stabilized.
In addition, if the hot water supply operation is performed in this state (the water stop valve 10 is open), the bypass pipe 9 acts as a simple bypass and can adjust the hot water temperature.
[0012]
Further, by providing the water stop valve 10, when the hot water supply operation is performed, the water stop valve 10 is closed and the flow path of the bypass pipe 9 is closed, so that all the water from the water inlet pipe 21 is the heat exchange pipe 2 for hot water supply. And a sufficient flow rate is ensured, and the efficiency of hot water heating can be increased.
In addition, when performing only the bath heating operation, the natural convection circuit is formed by opening the water stop valve 10 as described above, and the hot water in the hot water supply heat exchange pipe 2 is cooled by natural circulation, Suppresses typical boiling.
Further, the water stop valve 10 is not limited to the manual valve, but may be a solenoid valve, a servo valve, or a stepping motor valve.
[0013]
A different embodiment is described in FIG.
A check valve 12 is provided in the middle of the bypass pipe 9, and the check valve 12 includes a valve chamber 120 composed of an enlarged chamber having at least an inner diameter larger than the bypass pipe 9, and a frame provided in the valve chamber 120. A retaining ring 14 made of a body, and a valve body 13 made of a sphere formed of a material having a specific gravity of 1 or less enclosed below the retaining ring 14 in the valve chamber 120 are provided as a float valve. .
[0014]
The retaining ring 14 is engaged when the valve body 13 is lifted by the water flow from the lower side to the upper side when only the bath heating operation is performed, and the water passage is provided between the valve body 13 and the inner wall of the bypass pipe 9. Is formed (FIG. 2B).
On the other hand, the valve element 13 is lowered by the water flow from the upper side to the lower side when the hot water supply operation is performed, and comes into contact with and closes the lower end opening (valve seat) of the valve chamber 120, that is, the upper end opening of the bypass pipe 9. Stop the downward flow of water (Fig. 2a).
According to this configuration, water flow and water flow stop are automatically performed, no operation is required, and when the hot water supply operation is reliably performed, the water stop valve 10 is closed and the flow path of the bypass pipe 9 is closed. On the other hand, when only the bath heating operation is performed, a natural convection circuit is formed, and high-temperature water in the hot water supply heat exchange pipe 2 is cooled by natural circulation, thereby suppressing local boiling.
[0015]
3 and 4, different embodiments will be described.
Conventional check valves used in the past have a valve body with a specific gravity smaller than that of water (ie, 1 or less), durability against a predetermined back pressure (for example, 15 kgf / cm ² ), and use. The temperature environment must have durability against a maximum of 100 ° C., and the materials that can be used are limited (for example, polypropylene), and such materials have difficulty in durability and inferior in strength. It was.
[0016]
Therefore, in order to relax the restriction on the material and obtain a highly durable check valve, the check valve 15 shown in FIGS. 3 and 4 includes a valve chamber 150 connected to the bypass pipe 9, and a valve chamber 150. An annular valve seat 151 projecting from the valve seat 151 and a substantially top hat-shaped valve body 16 placed on the valve seat 151 are provided.
The valve body 16 formed in a substantially top-hat shape is formed with a bottomed cylindrical portion 160 that protrudes upward at the center and has a lower end open, and is formed at the periphery of the lower end opening of the bottomed cylindrical portion 160. An annular flange 161 extending outward is formed, and a plurality of drainage slits 162 are provided on the lower surface of the flange 161 (see FIG. 4).
[0017]
The operation will be described. When performing a hot water supply operation, the valve body 16 is pressed downward by its own weight and the flowing water pressure from the upper side to the lower side, and the lower surface of the flange 161 comes into contact with the upper surface of the valve seat 151 to pass the water passage. Close (see Fig. 3a).
At this time, a small amount of water is secured by the drainage slit 162.
Next, when only the bath heating operation is performed, natural convection through the hot water supply heat exchange pipe 2 and the bypass pipe 9 may go down through the bypass pipe 9, but the inclination of the hot water supply heat exchange pipe 2, Depending on the relative position with respect to the bypass pipe 9, the temperature distribution, and the like, there is a case where it goes up through the bypass pipe 9. Here, as in the latter case, natural convection from below to above occurs in the bypass pipe 9, and high-temperature water flows into the internal space 160A of the bottomed cylindrical portion 160 of the valve body 16 to generate buoyancy, thereby causing the valve body. 16 is pushed up to open the water passage (see FIG. 3B).
[0018]
With this configuration, since there is slight water flow from the drain slit 162 when the valve body 16 is closed, the valve body 16 does not adhere to the valve seat 151 and the opening operation of the valve body 16 becomes smooth.
Further, the valve body 16 can be manufactured from a material such as reinforced plastic having a specific gravity of 1 or more, the strength of the valve body 16 is increased, and the durability is improved.
[0019]
Still another embodiment of the check valve will be described with reference to FIGS.
The check valve 17 is closed when the valve body 18 descends and engages with a valve body 18 having a spherical shape in the valve chamber 170, a support spring 20 made of a shape memory alloy that supports and pushes up the valve body 18. A valve seat 19, a spring receiver 20 that engages and fixes the lower end of the support spring 20, and a bottom plate 22 that supports the valve seat 19 and the spring receiver 20 and has a communication hole 220 at the center. .
The support spring 20 may be a shape memory alloy coil spring as shown in the figure, but may also be a leaf spring, a cook thermo element, or the like.
Further, the valve body 18 is not limited to a spherical body, and may be a top or a plate-like body.
[0020]
The operation will be described. When low-temperature water flows through the bypass pipe 9 from the top to the bottom, that is, when the hot water supply operation is performed, the support spring 20 contracts and the valve body 18 is lowered and brought into contact with the valve seat 19 to pass the water passage. Is closed (see FIG. 5).
When only the bath heating operation is performed and low-temperature water flows from the bottom to the top in the bypass pipe 9, the support spring 20 extends to push up the valve body 18 and release the valve body 18 from the valve seat 19 to open the water passage. (See FIG. 6).
[0021]
Still another embodiment will be described with reference to FIG.
In the upward combustion type 1 can 2 circuit type hot water heater with a bath kettle, the heat exchanger 30 is configured so that the heat exchange pipe 31 for bath heating and the heat exchange pipe 32 for hot water supply are in contact with each other and the outer periphery of the can body (combustion chamber) 35. The bath heating heat exchange pipe 31 and the hot water supply heat exchange pipe 32 in the vicinity of the upper end of the can body 35 are formed into finned heat exchange pipes 310 and 320, and the upper end of the hot water supply heat exchange pipe 32 (outlet hot water) Side) and the lower end (incoming water side), both ends of the bypass pipe 33 are opened to communicate.
[0022]
The operation will be described. In the case of the bath heating single operation, since the upper end (the hot water side) of the hot water supply heat exchange pipe 32 is in contact with the cold water side of the bath heating heat exchange pipe 31, the finned heat exchange pipe 320 is cooled. On the contrary, when the lower part of the hot water supply heat exchange pipe 32 is heated, the hot water heated in the lower part of the hot water supply heat exchange pipe 32 rises, and the bypass pipe 33 causes the upper end of the hot water supply heat exchange pipe 32 ( The water cooled at the outlet side) descends to the lower end (inlet side) and causes natural convection to prevent boiling due to overheating.
[0023]
【The invention's effect】
According to the invention of claim 1, wherein, in a reverse combustion can of 2-circuit bath Kamazuke water heater, an inlet side end portion of the hot water supply heat exchanger tubes, communicates the tapping end at the bypass pipe, the A water stop valve is provided in the middle of the bypass pipe except for when the bath is heated alone, and the valve body of the water stop valve has a substantially top hat shape made of a material having a specific gravity of 1 or more. A bottomed cylindrical portion having a lower end opened, an annular flange extending outward is formed at the periphery of the lower end opening of the bottomed cylindrical portion, and a plurality of bottom flanges are formed on the lower surface of the flange A drainage slit is provided . Thereby, since there is slight water flow from the drainage slit when the valve body is closed, the valve body does not adhere to the valve seat, and the opening operation of the valve body becomes smooth. Moreover, a valve body can be manufactured with materials, such as reinforced plastics, whose specific gravity is 1 or more, the intensity | strength of a valve body increases, and durability improves.
[Brief description of the drawings]
FIG. 1 is a side view showing a schematic structure of a heat exchanger according to the present invention.
FIG. 2 is a cross-sectional view of a water stop valve in the present invention.
FIG. 3 is a cross-sectional view of a different embodiment of the present invention.
4 is a bottom view of the valve body shown in FIG. 3. FIG.
FIG. 5 is a cross-sectional view of yet another embodiment of the present invention.
FIG. 6 is an operation explanatory diagram of still another embodiment of the present invention.
FIG. 7 is a side view showing a schematic structure of a heat exchanger of still another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1 can 2 circuit type hot water heater with a bath pot, 2 heat exchange pipe for hot water supply 3 heat exchange pipe for bath heating, 4 can body (combustion chamber), 5 reverse combustion burner 6 fan, 9 bypass pipe, 10 water stop valve 20 Heat exchange pipe for hot water supply with fins, 30 Heat exchange pipe for heating baths with fins

Claims (1)

In a water heater with a reverse combustion type 1 can and 2 circuit type bath kettle, the inlet side end and the outlet side end of the heat exchange pipe for hot water supply are communicated with a bypass pipe, and the bath heating is operated in the middle of the bypass pipe. Other than the above, there is provided a water stop valve that closes, and the valve body of the water stop valve has a substantially silk hat shape formed of a material having a specific gravity of 1 or more, and the valve body protrudes upward at the center and the lower end is opened. A bottomed cylindrical part is formed, and an annular flange extending outward is formed on the periphery of the lower end opening of the bottomed cylindrical part,
A structure for preventing local boiling in a hot water supply circuit , wherein a plurality of drainage slits are provided on the lower surface of the flange .

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