JP6037158B2 - Heat source machine - Google Patents

Description

  The present invention relates to a heat source device that supplies heat by heating a heat medium such as hot water.

  Like a water heater that heats hot water and hot water circulation type heating equipment, it has a combustion device such as a burner and a heat exchanger inside the housing, and a heat medium such as hot water is supplied for the purpose of hot water supply and heating. Heat source machines for heating are widely known. In such a heat source machine, the amount of hot water and the temperature required by the user frequently change. Therefore, in the combustion device built in the heat source machine, the combustion amount is changed in accordance with changes in the hot water supply amount, the hot water supply temperature, and the like.

As such a heat source machine, for example, there is a water heater disclosed in Patent Document 1.
In the water heater disclosed in Patent Document 1, the region where the burner is arranged is divided into three, and the gas flow path for supplying fuel to the burner is branched into three. And it has the structure where fuel gas is supplied through each of the flow path branched into three with respect to the burner each distribute | arranged to the area | region divided into three. That is, for the burner arranged in each of the central part, the right part, and the left part, each of the parts branched into three gas flow paths is continuous, the central part, It has a structure capable of individually supplying fuel to the right and left regions.
And in the water heater disclosed by patent document 1, combustion operation | movement can be separately implemented in each area | region of a center part, a right side part, and a left side part.

  That is, in the water heater disclosed in Patent Document 1, the combustion operation is performed in at least one region of the center portion, the right side portion, and the left side portion, and the amount of combustion is determined by the combination of the portions that perform the combustion operation. It has a structure to switch. Specifically, the combustion operation is performed in all of the center, right side, and left side, the combustion operation is performed only in the center and right side, and the combustion operation is performed only in the center and left side. And a state in which the combustion operation is performed only in the central portion can be switched, and the combustion amount can be switched to four stages.

JP-A-9-105552

  By the way, in recent years, a heat source machine that can be installed in a narrow installation place (for example, a pipe shaft of a condominium or the like) has been desired from the market, and a heat source machine that has been downsized to meet such a demand has been developed. And as a heat exchanger employ | adopted with such a heat source machine, there exists a small-sized heat exchanger which provided the flowing water pipe | tube in the single stage. When such a small heat exchanger is employed, the manufacturing cost of the heat exchanger can be suppressed, so that the heat source device can be provided at low cost.

This small heat exchanger will be specifically described.
A heat exchanger called a fin-and-tube type is generally a canister having a substantially rectangular tube shape whose upper and lower parts are open, and the outer wall portion of the can body and meandering inside and outside the can body. It is comprised by the flowing water pipe extended and the fin integrally attached to the flowing water pipe.
Here, a general heat exchanger is usually provided with a plurality of flowing water pipes. That is, the water pipe extending meandering from one side in the horizontal direction to the other side (in the direction of arrow A1 in FIG. 8A) is folded up and down at the other end, and from the other side in the horizontal direction to the one side (see FIG. 8 (a) in the direction of arrow A2).
On the other hand, in the small heat exchanger described above, the flowing water pipe is meanderingly extended from one side in the horizontal direction to the other side (in the direction of arrow A1 in FIG. 8B), and directly to the outside of the can body. It has a structure that extends.
That is, the above-described small heat exchanger can be reduced in height by providing the flowing water pipes in a single stage (one stage) as compared with those provided in a plurality of stages. For this reason, even if the housing of the heat source machine is small, there is an advantage that the housing in the housing is easy.

  However, in the heat source apparatus employing such a small heat exchanger, when the above-described combustion amount switching operation is performed, hot water having a temperature much lower than the target temperature is discharged due to a temporary shortage of the combustion amount. So-called undershoot may occur. This will be specifically described below.

  In the following description, a heat exchanger having a single stage of flowing water pipes that meander from the right side to the left side in the horizontal direction is adopted, and the areas where the burners are arranged are the right side, the center, and the left side. In the heat source machine divided into three, the case where the combustion amount is changed by switching the region where the combustion operation is actually performed will be described as an example. More specifically, the combustion operation can be performed individually in each of the right side portion, the central portion, and the left side portion, and the right side of each of the upstream side, the midstream side, and the downstream side of the heat exchanger. A case will be described in which the combustion amount is changed by a heat source machine corresponding to the part, the center part, and the left part.

  In such a heat source machine, when switching from the state in which the combustion operation is performed in the center and the left side to the state in which the combustion operation is performed in the center and the right side, the upstream side (right side) of the water pipe is switched before the switching operation. The flowing hot water will flow downstream (left side) of the water pipe after the switching operation. Then, this hot water is not heated on the upstream side (right side) of the water pipe, and is not heated on the downstream side (left side). Then, the hot water discharged from the hot water becomes lower than the desired temperature.

More specifically, in the state before the switching operation, it is not heated greatly when passing through the upstream side, but is heated greatly when passing through the midstream side and when passing through the downstream side.
On the other hand, at the time of stabilization after the switching operation, when passing through the upstream side and when passing through the midstream side, they are heated greatly, and when passing through the downstream side, they are not heated greatly.
For this reason, when the switching operation is performed when the hot water passes through the upstream side of the flowing water pipe and further passes through the middle flow side, the hot water that has flowed upstream in the state before the switching operation is in the state after the switching operation. Flows downstream.
Then, hot water that has not been heated significantly on the upstream side flows out of the heat exchanger without being heated greatly on the downstream side. In other words, hot water that should have been heated greatly on the downstream side before switching is not heated greatly on the downstream side by performing the switching operation. As a result, hot water that is heated largely only on the middle stream side is discharged. For this reason, hot water having a temperature lower than the set temperature in the state before the switching operation and lower than the set temperature in the state after the switching operation is discharged. That is, a large undershoot occurs in which hot water is discharged at a temperature lower than the desired temperature.

  In addition, in the case where a heat exchanger in which the flowing water pipe extends over a plurality of stages is employed, it is difficult for large undershoots to occur even when the same combustion amount switching operation is performed.

In detail, in the heat source apparatus that employs a heat exchanger in which the water pipe extends over a plurality of stages, when the combustion amount switching operation similar to the above is performed, the right side of the first stage of the water pipe is flowing before the switching operation. Hot water will flow on the left side of the first stage of the water pipe after the switching operation. As a result, the hot water is not greatly heated at the first stage right side of the flowing water pipe, and is not heated greatly at the left side of the first stage. That is, in the first stage of the flowing water pipe, heating of hot water is insufficient as in the case described above.
However, in such a heat source machine, the hot water that has passed through the first stage of the water pipe continues to flow through the second stage of the water pipe. And this hot water is not heated greatly when flowing through the left side of the second stage, but is heated greatly when passing through the center part of the second stage and the right side of the second stage. That is, in the second and subsequent stages of the flowing water pipe, the hot water is heated as usual in the combustion operation after switching.

  And the ratio of the heating amount of the 1st-stage hot water to the heating amount of the hot water of the whole flowing water pipe becomes small, so that there are many steps | paragraphs of a flowing water pipe. In other words, the ratio of the amount of heat applied when the first stage passes out of the total amount of heat applied by the hot water passing through the entire flowing water pipe is reduced. For this reason, even if the hot water is insufficiently heated only in the first stage, the amount of heat applied in the first stage is only a small part of the total amount of heat applied in the entire heat exchanger. The temperature of the hot water discharged from the water does not deviate significantly from the target temperature. In other words, even if the hot water is insufficiently heated only in the first stage of the flowing water pipe and the tapping temperature falls below the target temperature, the tapping temperature stays slightly below the target temperature. . In other words, the tapping temperature in this case is lower than the target temperature, but remains within the error range. Therefore, in a heat source apparatus that employs a heat exchanger in which the flowing water pipe extends over a plurality of stages, it is difficult for large undershoots to occur when the combustion amount switching operation is performed.

  Furthermore, even if the flow pipe is a single-stage (one-stage) heat exchanger, if the flow pipe extends in a different direction, that is, after the flow pipe extends from the right side to the left side, When using a heat exchanger that folds and extends from the left side to the right side, or from the right side to the left side ... It is difficult to do. That is, in the heat source apparatus that employs the heat exchanger in which the water pipe extends in this manner and divides the area where the burner is arranged into three parts, a right side part, a central part, and a left side part, as described above. Even if the combustion amount switching operation is performed, a large undershoot hardly occurs.

  Specifically, in such a heat source machine, when the combustion amount switching operation similar to the above is performed, when hot water first flows from the right side of the water pipe to the left side of the water pipe, the hot water is The right side and the left side are not heated, resulting in insufficient heating. However, when it flows from the left side of the water pipe to the right side of the water pipe after the first turn, and then when it flows from the right side of the water pipe to the left side of the water pipe after the second turn, the first time When hot water flows in the left-right direction of the flowing water pipe after turning, the hot water is heated as usual in the combustion operation after switching.

  Accordingly, in this case, the greater the number of times the flow pipe is folded, the smaller the proportion of the portion before the first turn that occupies the entire flow pipe. In other words, the ratio of the amount of heat applied when the hot water passes through the water pipe before the first turn out of the total amount of heat applied along with the passage of the hot water pipe becomes small. For this reason, even if the hot water is insufficiently heated only before the first turn, the amount of heat applied before the first turn is only a small part of the total heat applied by the entire heat exchanger. The temperature of the hot water discharged from the heat exchanger does not greatly deviate from the target temperature. In other words, even if the hot water is insufficiently heated just before the first turn of the water pipe, and the tapping temperature falls below the target temperature, the tapping temperature will be slightly below the target temperature. Stay below. That is, it is difficult for large undershoots to occur when the combustion amount switching operation is performed.

  On the other hand, in the heat exchanger in which the water pipes are provided in a single stage (one stage), the heating amount of the hot water in the first stage becomes the heating amount of the hot water in the entire water pipe as it is. In other words, the amount of heat applied when passing through the first stage of the flowing water pipe is the same (substantially the same) as the total amount of heat applied by the heat exchanger. Therefore, if the hot water is insufficiently heated in the first stage of the flowing water pipe, this insufficient heating greatly affects the temperature of the hot water discharged from the heat exchanger. As a result, the temperature of the hot water discharged is targeted. There is a possibility that the temperature will be significantly below the tapping temperature. In other words, when the conventional switching operation of the combustion amount is performed in the heat source apparatus that employs the heat exchanger provided with a single flow water pipe, there is a possibility that a large undershoot may occur due to the structure.

  In view of the above-described problems of the prior art, the present invention provides a heat source device that does not generate a large undershoot during a combustion amount switching operation even if a small heat exchanger is employed. Is an issue.

Invention of Claim 1 for solving the said subject has a flame formation part, a fuel supply path, and a heat exchanger, The said heat exchanger is provided with the liquid flow path through which a liquid can flow, Heat exchange is performed between the liquid flowing through the liquid flow path and the combustion gas generated when the flame forming unit burns fuel, and the flame forming unit is an overall component of the heat exchanger. Are divided into a plurality of combustion regions corresponding to the flow direction of hot water, and can individually form a flame in each combustion region, and can be switched to increase or decrease the combustion region forming the flame, The plurality of combustion regions include a downstream combustion region corresponding to the downstream side of the liquid flow channel, an upstream combustion region corresponding to the upstream side of the liquid flow channel, and the upstream combustion region and the downstream combustion region. Including a midstream combustion region located between the downstream combustion regions From the state in which the flame is formed in the middle flow side combustion region to the state in which no flame is formed in the downstream combustion region, and the state in which the flame is formed in the middle flow side combustion region and the upstream combustion region When performing switching , the heat source machine is characterized in that it performs an inter-switching operation that maintains a state in which a flame is formed in the upstream combustion region, the midstream combustion region, and the downstream combustion region. .

In the heat source apparatus of the present invention, the flame forming unit is partitioned into a plurality of combustion regions corresponding to the overall flow direction of the hot water of the heat exchanger, and a flame can be formed individually in each combustion region. . And the structure which can change the combustion quantity by increasing / decreasing the combustion area | region which forms a flame by switching the state which forms a flame in each combustion area | region, and the state which does not form a flame, respectively.
In the heat source apparatus of the present invention, the plurality of divided combustion regions include the downstream combustion region corresponding to the downstream side of the liquid flow path of the heat exchanger. When the combustion amount switching operation is performed to change the state in which the flame is formed in the downstream combustion region to the state in which the flame is not formed in the downstream combustion region, the downstream combustion region An inter-switching operation is performed to maintain the state of forming a flame.

  When such an inter-switching operation is performed, hot water flowing downstream can be greatly heated immediately after switching. Therefore, when the hot water that should have been heated on the downstream side before the switching operation flows into the downstream side after the switching operation, the hot water that has flowed into the downstream side can be reliably heated.

  This will be described assuming a specific heat source machine.

  First, it is assumed that the assumed heat source machine hardly heats hot water on the upstream side of the liquid flow path and heats hot water largely on the downstream side of the liquid flow path before the switching operation. Then, when stable after the switching operation, the hot water is heated largely on the upstream side of the liquid channel, and the hot water is hardly heated on the downstream side of the liquid channel. In such a heat source machine, when the switching operation is performed while hot water is flowing through the liquid flow path, the hot water that has flowed upstream before the switching operation flows downstream after the switching operation.

  Here, if the inter-switching operation is not performed, the hot water that is hardly heated on the upstream side of the liquid flow channel flows downstream after the switching operation and is hardly heated on the downstream side. That is, the flowing hot water is in a state of insufficient heating.

On the other hand, in the present invention, the switching operation is performed during the switching operation. By performing the switching operation, the hot water that has flowed upstream of the liquid channel before switching the combustion region flows downstream of the liquid channel during the switching operation, and then is discharged to the outside. Is done. Here, since the state in which the flame is formed in the downstream combustion region is maintained during the switching operation, the hot water is greatly heated on the downstream side of the liquid flow path. That is, when the switching operation is performed, the hot water flowing upstream before the switching operation is greatly heated on the downstream side of the liquid flow path, and as a result, heated as in the state before the switching operation. It will be discharged to the outside later.
Therefore, if the inter-switching operation is performed during the switching operation, the hot water already flowing into the liquid flow path is heated in the state before switching the combustion region and then discharged to the outside of the liquid flow path. The hot water newly flowing into the liquid flow path is heated in the combustion region after switching. Then, the hot water heated in the state before switching of the combustion region and the hot water heated in the state after switching of the combustion region are continuously discharged from the liquid flow path, and hot water with insufficient heating is discharged. It will not be done. Therefore, a large undershoot does not occur during the combustion region switching operation.

In the present invention, the plurality of combustion regions include an upstream combustion region corresponding to the upstream side of the liquid flow path, and a midstream combustion region located between the upstream combustion region and the downstream combustion region, A state in which no flame is formed in the downstream combustion region from a state in which a flame is formed in the downstream combustion region and the midstream combustion region, and a flame is generated in the midstream combustion region and the upstream combustion region. When switching to a state in which a flame is formed, an inter-switching operation is performed to maintain a state in which a flame is formed in the upstream combustion region, the midstream combustion region, and the downstream combustion region .

  According to this configuration, since the switching operation is performed when the combustion amount switching operation in which a large undershoot is relatively likely to occur, the occurrence of a large undershoot can be prevented more reliably.

The invention according to claim 2 is the heat source apparatus according to claim 1 , wherein the switching operation is continuously performed for a predetermined time.

The invention according to claim 3, wherein the switching between the operation, which is a heat source machine according to claim 1, characterized in that ends on condition that a predetermined amount or more passing water is detected.

  According to these configurations, the inter-switching operation is continued for a time sufficient for the hot water that has not been heated on the upstream side of the liquid flow path before switching the combustion region to complete the downstream passage. Accordingly, since the hot water is continuously heated while the hot water flows on the downstream side, the temperature of the hot water that has not been heated on the upstream side can be more reliably increased. Therefore, the occurrence of a large undershoot can be prevented more reliably.

In the present invention, when switching from the state in which the flame is formed in the downstream combustion region to the state in which the flame is not formed in the downstream combustion region, during the switching to maintain the state in which the flame is formed in the downstream combustion region The operation is carried out. For this reason, when hot water flowing into the liquid flow path of the heat exchanger before switching the combustion region and flowing upstream of the liquid flow channel flows into the downstream side of the liquid flow channel after switching the combustion region, The hot water flowing into the downstream side of the liquid channel can be heated.
This prevents hot water that has not been heated on the upstream side of the liquid flow path of the heat exchanger before switching of the combustion region from being heated on the downstream side of the liquid flow path, thereby preventing the occurrence of a large undershoot. There is an effect.

It is an operation principle figure which shows the hot-water supply apparatus concerning the embodiment of the present invention. It is a perspective view which shows the primary heat exchanger of FIG. 1, and abbreviate | omits and shows a fin. It is explanatory drawing which shows the flow of the hot water in the primary heat exchanger of FIG. 1, and abbreviate | omits and shows a fin. It is explanatory drawing which shows a mode that the stage number of combustion operation | movement is changed in the combustion part of FIG. It is explanatory drawing which shows a mode that hot water becomes insufficiently heated when changing the stage number of combustion operation | movement, without performing the operation | movement between switching of this embodiment, (a) shows the state before change of a stage number, (B) shows the state after changing the number of stages. It is explanatory drawing which shows a mode that operation between switching is implemented when changing the number of steps in the hot water supply apparatus of FIG. 1, (a) shows the state before the change of the number of steps, (b) follows the state of (a). (C) shows the state after changing the number of stages. It is a flowchart which shows the procedure at the time of implementing the change operation | movement of a stage number with the hot water supply apparatus of FIG. It is explanatory drawing explaining the extending direction of the flow pipe of the general heat exchanger which provided the water flow pipe in multiple steps, and the small heat exchanger which provided the water flow pipe in the single stage, (a) A heat exchanger is shown, (b) shows the small heat exchanger provided in the single stage.

  Hereinafter, although the hot water supply apparatus 1 (heat source machine) which concerns on embodiment of this invention is demonstrated in detail, this invention is not limited to these examples. In the following description, the positional relationship between front, rear, up, down, left and right will be described based on a normal installation state unless otherwise specified.

  As shown in FIG. 1, the hot water supply device 1 includes a combustion unit 2 that burns fuel supplied from the outside to generate combustion gas, a blower 3 that supplies combustion air to the combustion unit 2, and a combustion unit A so-called latent heat recovery type comprising a primary heat exchanger 4 (heat exchanger) for recovering mainly sensible heat of the combustion gas generated in 2 and a secondary heat exchanger 5 (heat exchanger) for recovering latent heat; It is called.

  And the hot water supply apparatus 1 of this embodiment is provided with the fuel supply system 6 for supplying fuel gas to the combustion part 2 from the fuel supply source which is not shown in figure. Moreover, the hot water supply apparatus 1 of this embodiment flows the hot water introduced from the water supply source which is not shown in figure into the secondary heat exchanger 5 and the primary heat exchanger 4, and heats with the secondary heat exchanger 5 and the primary heat exchanger 4 A hot water supply system 7 that performs a general hot water supply operation for discharging hot water from the hot water tap 55 and a drain discharge system 8 for neutralizing the drain generated in the secondary heat exchanger 5 and discharging the drain to the outside are provided. .

  Furthermore, the hot water supply apparatus 1 of the present embodiment includes a control device 9 inside, and the hot water supply apparatus 1 performs various operations when the control device 9 issues an operation command to each part of the hot water supply device 1.

The combustion unit 2 includes a flame forming unit in which a plurality of burners are formed in parallel. The flame forming unit includes three combustion regions (upstream combustion region α, midstream combustion region β, and downstream combustion region). γ).
In the three combustion regions (upstream combustion region α, middle flow combustion region β, and downstream combustion region γ), there are three burner groups (first burner group 15 and second burner group) each composed of a plurality of burners. 16, the third burner group 17) is arranged.
More specifically, a first burner group 15 formed by two burners, a second burner group 16 formed by three burners, and a third burner group 17 formed by five burners, However, they are arranged in parallel in the horizontal direction.
The first burner group 15 is arranged in the center, and the second burner group 16 and the third burner group 17 are arranged on the outside thereof.
Details of the arrangement of the combustion region and the burner group will be described later.

Further, an igniter 19 as an ignition plug and a flame rod 20 as flame detection means for detecting the presence or absence of the formed flame are arranged immediately above the first burner group 15 (middle flow side combustion region β).
That is, the igniter 19 is energized to disperse sparks, so that the fuel gas released from the burner can be ignited. The flame rod 20 can detect the presence or absence of a flame formed by igniting the fuel gas.
The igniter 19 is actuated by a signal from the control device 9, and the frame rod 20 allows a flame current generated when a flame is generated to flow. The flame presence / absence information is controlled as a voltage signal. It functions as an electrode used for outputting to the device 9.

  The blower 3 incorporates a motor and an impeller (not shown) inside as well as known ones, and changes the rotation speed according to the combustion state of the flame forming part (burner) of the combustion part 2 to adjust the air flow and the air pressure. It is possible.

  The primary heat exchanger 4 is a gas / liquid heat exchanger, and as shown in FIG. 2, a frame body 24 whose outer shape is a substantially rectangular tube shape and whose upper and lower ends are opened, and a frame body 24. And a plate-like fin 26 (see FIG. 1 that is not shown in FIG. 2), which are integrally formed by brazing or the like.

  As shown in FIG. 2, the flowing water pipe 25 is a pipe extending meandering in the horizontal direction. More specifically, the flowing water pipe 25 extends through a water inlet pipe portion 28 which is a pipe into which hot water flows and a plurality of fins 26 (see FIG. 1 which is not shown in FIG. 2) inside the frame body 24. The straight pipe part 29, the bend pipe part 30 that bends and extends outside the frame body 24, and the water discharge pipe part 31 that is a pipe through which hot water flows out are connected to each other.

Here, as shown in FIG. 3, the flowing water pipe 25 is provided with a plurality of straight pipe parts 29 and a plurality of bend pipe parts 30 between the water inlet pipe part 28 and the water outlet pipe part 31. These are connected and formed. Specifically, in the flowing water pipe 25, from the upstream side in the flowing direction of hot water, the inlet pipe part 28, the first straight pipe part 29a, the first bend pipe part 30a, the second straight pipe part 29b, 2 The thirteenth bend pipe section 30b, ..., the twelfth straight pipe section 29l, the twelfth bend pipe section 301, the thirteenth straight pipe section 29m, and the water discharge pipe section 31 are successively connected. Yes.
Thus, the flowing water pipe 25 is a pipe having a portion extending meandering between the water inlet pipe portion 28 and the water outlet pipe portion 31. The water inlet pipe portion 28 is located on one side in the horizontal direction (right side in FIG. 3), and the water outlet pipe portion 31 is located on the other side in the horizontal direction (left side in FIG. 3). Then, the piping is extended from one side in the horizontal direction to the other side (from the right side to the left side in FIG. 3). Further, when attention is paid to the meandering portion of the water flow pipe 25, it extends in the direction (up and down direction in FIG. 3) intersecting the extending direction (from the right side to the left side in FIG. 3). It is folded at the edge area. Then, the folded portion of the edge region extends in the entire extending direction (the direction from the right side to the left side in FIG. 3) while being curved. That is, the meandering and extending portion of the water flow pipe 25 repeats extending and folding, and each time the folding is repeated, the portion gradually extends in the entire extending direction (the direction from the right side to the left side in FIG. 3).

  Therefore, it can be said that this flowing water pipe 25 is a pipe extending meandering from one side in the horizontal direction to the other side (from the right side to the left side in FIG. 3). From this, the flow direction of the entire hot water in the primary heat exchanger 4 is from one side in the horizontal direction to the other side (from the right side to the left side in FIG. 3).

  Specifically, since the flowing water pipe 25 is extended in this way, the hot water flowing in from the water inlet pipe portion 28 flows between the straight pipe portion 29 located inside the frame body 24 and the frame body 24. It will alternately pass through the bend pipe part 30 located outside. Specifically, the hot water that has passed through the straight pipe portion 29 (29a) inside the frame body 24 once flows to the outside of the frame body 24 and is folded back by the bend pipe portion 30 (30a), so that the frame body again. 24 flows into the interior. And it passes along the straight pipe part 29 (29b) in the position adjacent to the straight pipe part 29 (29a) which passed before the return | turnback. By repeating this, the hot water flows into the straight pipe portion 29 (29 m) located on the most downstream side in the hot water flow direction. Then, the hot water reaches the water discharge pipe portion 31 from the straight pipe portion 29 (29 m) and flows out from the water discharge pipe portion 31 to the outside.

  Here, the primary heat exchanger 4 is divided into three regions in the overall hot water flow direction of the primary heat exchanger 4 (the direction from the right side to the left side in FIG. 3), and the hot water flow direction upstream from the upstream side in order. A part A, a midstream part B, and a downstream part C are assumed. Then, as shown in FIG. 1, the second burner group 16, the first burner group 15, and the third burner group 17 of the combustion section 2 are respectively provided below the upstream part A, the middle stream part B, and the downstream part C. It has been arranged. In other words, the upstream combustion region α, the middle combustion region β, and the downstream combustion region γ correspond to the upstream portion A, the middle flow portion B, and the downstream portion C, respectively.

  That is, the above-described three combustion regions (upstream combustion region α, midstream combustion region β, downstream combustion region γ) of the combustion section 2 and three burner groups (first burner group 15 and second burner group 16). The third burner group 17) is in a parallel state along the overall hot water flow direction (the direction from the right side to the left side in FIG. 1) of the primary heat exchanger 4 positioned above. And the 2nd burner group 16, the 1st burner group 15, and the 3rd burner group 17 are arranged in parallel from the upstream of the whole hot water flow direction of the primary heat exchanger 4. Further, the primary heat exchanger 4 is arranged in parallel from the upstream in the hot water flow direction in the order of the upstream combustion region α, the midstream combustion region β, and the downstream combustion region γ.

Here, as described above, the third burner group 17, the second burner group 16, and the first burner group 15 are configured by five, three, and two burners, respectively. Therefore, the three burner groups burn in the order of the third burner group 17, the second burner group 16, and the first burner group 15 (downstream combustion region γ, upstream combustion region α, and midstream combustion region β). The amount of combustion during operation is large. In other words, the combustion amount of the third burner group 17 disposed in the vicinity of the downstream side of the flowing water pipe 25 is the largest, and the combustion amount of the second burner group 16 disposed in the vicinity of the upstream side of the flowing water pipe 25 is the next largest, The combustion amount of the first burner group 15 arranged in the vicinity of the center of the flowing water pipe 25 is the smallest.
In addition, each combustion region (upstream combustion region α, middle flow side combustion region β, downstream combustion region γ) has a corresponding burner group (second burner group 16, first burner group 15, third burner group 17). The downstream combustion region γ corresponding to the third burner group 17, the upstream combustion region α corresponding to the second burner group 16, and the midstream combustion corresponding to the first burner group 15 are increased in proportion to the number of burners. It becomes wider in the order of the region β.

  In the primary heat exchanger 4, as shown in FIG. 2, the vertical height positions of the straight pipe portions 29 and the bend pipe portions 30 that are a part of the flowing water pipe 25 are substantially the same. It has become. That is, the flowing water pipe 25 is a pipe provided in a single stage (one stage) and extending meandering in the horizontal direction. In the primary heat exchanger 4 of the present embodiment, the flowing water pipes 25 are provided in a single stage (one stage) as described above, and the height of the primary heat exchanger 4 is lower than that provided in a plurality of stages. (The length in the vertical direction is short).

  The secondary heat exchanger 5 is a known gas / liquid heat exchanger, and is a part that recovers the thermal energy of the combustion gas that could not be recovered by the primary heat exchanger 4, and is combusted by the primary heat exchanger 4. It is arranged downstream in the gas flow direction. This secondary heat exchanger 5 is formed by incorporating a pipe (not shown) through which hot water flows inside the box-shaped body, and adopts stainless steel or the like having high corrosion resistance as a raw material of this pipe. As a result, the structure is superior in corrosion resistance compared to the primary heat exchanger 4.

  As shown in FIG. 1, the fuel supply system 6 includes a fuel supply pipe 35 (fuel supply path) for supplying fuel gas such as natural gas or city gas supplied from a fuel supply source (not shown) to the combustion unit 2. The original gas electromagnetic valve 36 provided in the middle of the fuel supply pipe 35 and the gas proportional valve 37 provided downstream of the original gas electromagnetic valve 36 in the fuel gas flow direction are provided. Further, on the downstream side of the gas proportional valve 37 in the flow direction of the fuel gas, there are three solenoid valves 38 (open / close valve), second solenoid valve 39 (open / close valve), and third solenoid valve 40 (open / close valve). A solenoid valve is provided.

  The original gas solenoid valve 36 is a valve that is always opened while being burned in the combustion section 2 and is closed when the combustion is stopped.

  The gas proportional valve 37 can adjust the amount of fuel gas supplied from a gas supply source (not shown) to the combustion unit 2 by adjusting the opening.

  The first solenoid valve 38, the second solenoid valve 39, and the third solenoid valve 40 are independently controlled, and the first burner group 15, the second burner group 16, the third burner group described above. 17 respectively. Accordingly, by opening and closing each of the first solenoid valve 38, the second solenoid valve 39, and the third solenoid valve 40, fuel gas can be supplied and shut off independently for each burner group. In other words, the fuel gas can be supplied and shut off independently for each combustion region.

  The hot water supply system 7 includes a water inlet pipe 43, a hot water outlet pipe 44, and a bypass pipe 45 that connects the water inlet pipe 43 and the hot water outlet pipe 44.

  The inlet pipe 43 is a pipe for flowing hot water supplied from a water supply source (not shown) to the secondary heat exchanger 5 and the primary heat exchanger 4. In the middle of the inlet pipe 43, an incoming water flow rate sensor 47 and an incoming water temperature sensor 48 are provided. The incoming water flow sensor 47 and the incoming water temperature sensor 48 are disposed downstream of the connecting portion of the bypass pipe 45 in the incoming pipe 43 in the flowing direction of hot water and are electrically connected to the control device 9.

The hot water outlet pipe 44 is a pipe for supplying hot water that has passed through the secondary heat exchanger 5 and the primary heat exchanger 4 to the hot water tap 55. The hot water discharge pipe 44 is provided with a hot water temperature sensor 50 and a hot water flow rate adjusting valve 51 on the downstream side of the connection portion of the bypass pipe 45.
The hot water temperature sensor 50 can detect the temperature of hot water supplied to the hot water tap 55 and is electrically connected to the control device 9. The hot water flow rate adjusting valve 51 can increase or decrease the amount of hot water flowing to the hot water tap 55 by changing the opening degree.

  The bypass pipe 45 is a pipe that bypasses the secondary heat exchanger 5 and the primary heat exchanger 4 and continues the water inlet pipe 43 and the hot water outlet pipe 44.

  Next, the hot water supply operation of the hot water supply apparatus 1 of the present embodiment will be described.

  When a user makes a hot water supply request to the hot water supply device 1 by opening the hot water tap 55 or the like, hot water is supplied to the water inlet pipe 43 from a water supply source (not shown). And when the water quantity more than fixed amount is confirmed by the water intake pipe 43, the hot water supply apparatus 1 will supply fuel gas to the combustion part 2, and will perform the combustion operation | movement which burns fuel gas.

  In this combustion operation, the control device 9 determines the target heating amount (necessary for heating the hot water based on the obtained water amount and temperature per unit time of the hot water flowing through the inlet pipe 43 and the set temperature set by a remote controller or the like. Calculated). And the control apparatus 9 determines the combustion amount in the combustion part 2 based on the target heating amount (heat amount required for the heating of hot water) acquired by calculation.

When the amount of combustion in the combustion unit 2 is determined, the burner group that actually performs the combustion operation and the amount of fuel gas supplied to the burner group are determined accordingly.
That is, it is determined whether or not to perform the combustion operation for each of the plurality of burner groups (first burner group 15, second burner group 16, and third burner group 17), and the fuel gas supplied to the burner group performing the combustion operation The supply amount is determined.

Then, the original gas solenoid valve 36 is opened, and among the three solenoid valves (the first solenoid valve 38, the second solenoid valve 39, and the third solenoid valve 40), the solenoid corresponding to the burner group that actually performs the combustion operation. Leave the valve open.
That is, if the combustion operation is actually performed only in the first burner group 15 and the combustion operation is not performed in the second burner group 16 and the third burner group 17, only the first solenoid valve 38 is opened. Each of the three solenoid valves is appropriately opened and closed, such that the second solenoid valve 39 and the third solenoid valve 40 are closed.

  Further, the opening degree of the gas proportional valve 37 is adjusted based on the determined supply amount of the fuel gas. That is, by adjusting the opening of the gas proportional valve 37, the fuel gas supplied to the burner group that performs the combustion operation is increased or decreased. As a result, the determined appropriate amount of fuel gas is supplied to the burner group.

Thus, in the hot water supply device 1 of the present embodiment, the number of burners that perform the combustion operation, that is, the combination of burner groups (combustion region) that performs the combustion operation, and the opening of the gas proportional valve 37 are changed. As a result, the amount of combustion can be increased or decreased.
That is, the number of burners that perform the combustion operation (burners that perform the combustion operation) by opening and closing the three electromagnetic valves (the first electromagnetic valve 38, the second electromagnetic valve 39, and the third electromagnetic valve 40) as necessary. A combination of groups, and a combination of combustion regions in which a combustion operation is performed) is changed. Further, the amount of fuel supplied to the burner (burner group) is changed by changing the opening of the gas proportional valve 37. And the amount of combustion is determined by the number of burners which perform combustion operation, and the amount of fuel to a burner (burner group).

  A combustion operation is performed with the determined combustion amount, and combustion gas is generated when the mixed gas of fuel gas and air is burned in the combustion section 2. And the produced | generated combustion gas passes the primary heat exchanger 4 and the secondary heat exchanger 5 in order, and is discharged | emitted outside from the exhaust part 10 (refer FIG. 1).

  On the other hand, the hot water flowing through the water inlet pipe 43 passes through the secondary heat exchanger 5 and the primary heat exchanger 4 in this order, and then flows into the hot water outlet pipe 44. And when hot water passes the secondary heat exchanger 5 and the primary heat exchanger 4, it heats up by exchanging heat with combustion gas. More specifically, hot water that has flowed into the secondary heat exchanger 5 from the water supply source such as a water pipe or an elevated water tank through the water inlet pipe 43 is preheated by the latent heat of the combustion gas in the secondary heat exchanger 5. . Then, when the preheated hot water flows into the primary heat exchanger 4, the primary heat exchanger 4 performs the main heating to the set temperature by the sensible heat of the combustion gas. Then, the hot water heated in the primary heat exchanger 4 flows out to the hot water discharge pipe 44 and is discharged from the hot water tap 55 for use.

  Further, in the hot water supply apparatus 1 of the present embodiment, when the required hot water flow rate or hot water temperature is changed in a state where hot water of a constant flow rate is discharged from the hot water tap 55, the combustion amount is changed accordingly. . Specifically, a target heating amount (amount of heat necessary for heating the hot water) is determined every predetermined time (for example, 0.1 seconds), and the determined heating amount (amount of heat necessary for heating the hot water) is set. The amount of combustion is determined.

  Here, in a state where hot water of a constant flow rate has already been discharged, when determining the target heating amount (the amount of heat necessary for heating the hot water), the amount and temperature of the hot water flowing through the inlet pipe 43 described above, the remote controller, etc. In addition to the set temperature, the hot water temperature acquired by the hot water temperature sensor 50 is used as necessary. That is, the hot water temperature is added to the incoming water amount, incoming water temperature, and set temperature as required, and the target heating amount (the amount of heat necessary for heating the hot water) is determined based on these factors. When the combustion amount is determined from the target heating amount (the amount of heat necessary for heating the hot water), the number of burners (combination of burner groups) that perform the combustion operation to achieve this combustion amount and the gas proportional The opening degree of the valve 37 is changed as necessary, and the combustion operation is performed.

  As described above, in the hot water supply apparatus 1 of the present embodiment, the combustion operation is performed while appropriately changing the combustion amount from the start to the end of the hot water supply operation, that is, while the hot water supply operation is continued. Yes.

  By the way, in the hot water supply device 1 of the present embodiment, as described above, the number of burners that actually perform the combustion operation is changed as necessary. More specifically, the number of burners that actually perform the combustion operation can be switched in five stages (a plurality of stages). When the opening degree of the gas proportional valve 37 is the same, the combustion amount increases as the number of stages increases. The state of each stage will be described in detail below with reference to FIG.

  In the state of one stage, the combustion operation is actually performed only by the burners belonging to the first burner group 15. That is, a flame is formed only in the first burner group 15 (middle flow combustion region β), and a flame is formed in the second burner group 16 (upstream combustion region α) and the third burner group 17 (downstream combustion region γ). It has not been done. In this state, the first electromagnetic valve 38 is open, and the second electromagnetic valve 39 and the third electromagnetic valve 40 are closed.

  In the two-stage state, the combustion operation is actually performed only with the burners belonging to the second burner group 16. That is, a flame is formed in the second burner group 16 (upstream combustion region α), and a flame is formed in the first burner group 15 (middle flow combustion region β) and the third burner group 17 (downstream combustion region γ). It is not in a state.

  In this two-stage state, the number of combustion regions in which a flame is formed does not change compared to the one-stage state, but the upstream combustion region α corresponding to the second burner group 16 corresponds to the first burner group 15. Is larger than the middle flow side combustion region β, and the range in which the flame is formed is wide, so the combustion amount is higher than in the first stage (the combustion region in which the flame is formed is increased) ).

  In the two-stage state, the second electromagnetic valve 39 is in an open state, and the first electromagnetic valve 38 and the third electromagnetic valve 40 are in a closed state.

  In the three-stage state, the combustion operation is actually performed by the burners belonging to the first burner group 15 and the burners belonging to the second burner group 16. That is, a flame is formed in the first burner group 15 (middle flow side combustion region β) and the second burner group 16 (upstream combustion region α), and a flame is formed in the third burner group 17 (downstream combustion region γ). It is not in a state. In this state, the first electromagnetic valve 38 and the second electromagnetic valve 39 are open, and the third electromagnetic valve 40 is closed.

In the four-stage state, the combustion operation is actually performed by the burners belonging to the first burner group 15 and the burners belonging to the third burner group 17. That is, a flame is formed in the first burner group 15 (middle flow combustion region β) and the third burner group 17 (downstream combustion region γ), and a flame is formed in the second burner group 16 (upstream combustion region α). It is not in a state.
In this four-stage state, the number of combustion regions in which a flame is formed does not change compared to the three-stage state, but the downstream combustion region γ corresponding to the third burner group 17 corresponds to the second burner group 16. It is wider than the upstream combustion region α, and the combustion amount is higher than that in the three-stage state (the combustion region where the flame is formed is increased).
In this state, the first solenoid valve 38 and the third solenoid valve 40 are open, and the second solenoid valve 39 is closed.

In the five-stage state, all the burner groups (the first burner group 15, the second burner group 16, the third burner group 17) actually perform the combustion operation. That is, the combustion operation is actually performed in all the burners. Therefore, a flame is formed in all the combustion regions (upstream combustion region α, midstream combustion region β, and downstream combustion region γ). In this state, all three solenoid valves (the first solenoid valve 38, the second solenoid valve 39, and the third solenoid valve 40) are in the open state.
When the number of combustion stages (fuel region) is switched from a certain number of stages to the number of stages one level higher or the number one level lower, the amount of combustion itself is adjusted before and after switching the combustion quantity by adjusting the opening of the gas proportional valve 37. It is possible to achieve the same amount of combustion. Therefore, by adjusting the opening of the gas proportional valve 37, it is possible to linearly increase or decrease the combustion amount before and after switching the number of combustion stages (it is possible to increase or decrease the combustion amount gently).

  Above, description about the hot water supply operation | movement of the hot water supply apparatus 1 of this embodiment and description of the basic combustion operation accompanying a hot water supply operation are complete | finished.

  Here, a case where the number of stages of the burner (burner group) is changed when hot water is heated by the primary heat exchanger 4 will be described. Here, the case where the hot water is heated while performing the combustion operation in the four-stage state will be described as an example when the state is changed to the three-stage state.

  As described above, the second burner group 16 (upstream combustion region α) and the first burner group 15 of the combustion unit 2 are disposed below the upstream part A, the middle stream part B, and the downstream part C of the primary heat exchanger 4. (Middle flow side combustion region β) and third burner group 17 (downstream side combustion region γ) are arranged (see FIGS. 1 and 5).

  Therefore, when the combustion operation is performed in a four-stage state, as shown in FIG. 5A, the hot water flowing through the middle stream portion B and the downstream portion C of the primary heat exchanger 4 is heated relatively large. Thus, the portion flowing in the upstream portion A is not heated greatly.

  When the combustion operation is performed in the three-stage state, the hot water flowing through the upstream portion A and the midstream portion B of the primary heat exchanger 4 is heated relatively large as shown in FIG. Thus, the portion flowing in the downstream portion C is not heated greatly.

  Therefore, if the hot water is changed from the four-stage state to the three-stage state immediately after passing through the upstream portion A and the midstream portion B of the primary heat exchanger 4, the hot water flowing into the primary heat exchanger 4 is 4 Upstream part A (see FIG. 5 (a)) in which the combustion operation is performed in the stage state, and middle stream part B (see FIG. 5 (a)) in which the combustion operation is performed in the four stage state, The downstream portion C (see FIG. 5B) where the combustion operation is performed in this state will flow in order. That is, the hot water that has passed through the upstream portion A and the middle flow portion B (the thick line portion in FIG. 5A) of the primary heat exchanger 4 flows toward the downstream portion C side (the thick line portion in FIG. 5B). . From this, the hot water flowing into the primary heat exchanger 4 is hardly heated in the upstream portion A, greatly heated in the midstream portion B, and hardly heated when flowing through the downstream portion C. In other words, the hot water flowing through the primary heat exchanger 4 is heated greatly only when passing through the midstream portion B, and hardly heated in each of the upstream portion A and the downstream portion C.

  Therefore, in this case, since the same heating as in the case of heating in the state of 1 stage will be performed, the case of heating in the state of 3 stages and the case of heating in the state of 4 stages Hot water having a temperature lower than that in either case is discharged from the primary heat exchanger 4. This can be a factor in generating a large undershoot in which hot water having a temperature much lower than the target temperature is discharged.

  Therefore, the hot water supply device 1 of the present embodiment is a characteristic operation of the present embodiment in order to prevent the occurrence of a large undershoot due to the change in the number of burners that actually perform the combustion operation as described above. The operation during switching is performed. This switching operation is an operation that is performed when the number of burners that actually perform the combustion operation is changed, that is, when the number of stages of the combustion operation is changed. The inter-switching operation that is a characteristic operation of the present embodiment will be described in detail below.

The inter-switching operation of the present embodiment is a predetermined time t (for example, a predetermined combustion time in the burner group (the third burner group 17 and the downstream combustion region γ) located on the downstream side of the primary heat exchanger 4. This operation is forcibly performed only for 1 second).
First, the outline of the operation during switching is changed to perform the combustion operation in a three-stage state when the hot water is heated while performing the combustion operation in a four-stage state as in the above case. An example will be described.

  When the combustion operation is performed in the four-stage state, as shown in FIG. 6A, the hot water flowing through the middle portion B and the downstream portion C of the primary heat exchanger 4 is heated relatively large, The hot water flowing in the upstream portion A (the thick line portion in FIG. 6A) is hardly heated. In other words, when hot water passes through the upstream portion A and the midstream portion B, it is hardly heated in the upstream portion A and is heated greatly only in the midstream portion B.

  When hot water passes through the upstream part A and the midstream part B, the number of burners (combination of burner groups) that actually perform the combustion operation is changed to a three-stage state. Before the hot water supply device 1 of this embodiment performs the combustion operation in the third burner group 17 (the state in which a flame is formed in the downstream combustion region γ) is performed during switching. More specifically, in the hot water supply apparatus 1 of the present embodiment, a combustion operation in a five-stage state is performed as the operation during switching.

  On the other hand, the hot water that has passed through the upstream portion A and the midstream portion B of the primary heat exchanger 4 flows toward the downstream portion C side (the bold line portion in FIG. 6B). For this reason, when the hot water that has flowed through the upstream portion A and the middle flow portion B in the four-stage state, that is, hot water that is largely heated only in the middle flow portion B without being heated in the upstream portion A flows through the downstream portion C. As shown in FIG. 6B, an inter-switching operation for performing the combustion operation in a five-stage state is performed. And while the operation between switching is implemented, since it will be in the state where the flame was formed in the downstream combustion area | region (gamma) located under the downstream part C, the hot water flowing through the downstream part C is heated greatly. Become. As a result, the hot water flowing through the upstream portion A and the midstream portion B in the four-stage state is greatly heated not only in the midstream portion B but also in the downstream portion C. In other words, by continuously performing the combustion operation and the switching operation in the four-stage state, the hot water flowing through the upstream portion A and the midstream portion B in the four-stage state is as if in the four-stage state. Heating is performed in the same manner as when the combustion operation is continued. That is, when flowing through the upstream portion A, it is not heated greatly, and when flowing through the midstream portion B and the downstream portion C, it is heated relatively large.

  And when predetermined time t (for example, 1 second) passes, the operation | movement between switching will be complete | finished and the combustion operation | movement in a three-stage state will be started. Here, as shown in FIG. 6 (c), when the combustion operation in the three-stage state is started, it flows through the upstream portion A and the midstream portion B in the four-stage state, and downstream during the switching operation. The hot water that has flowed through the portion C (the hot water indicated by the thick lines in FIGS. 6A and 6B) has already passed through the downstream portion C and has flowed out of the primary heat exchanger 4.

  In addition, when the inter-switching operation is performed (see FIG. 6B), the hot water flowing through the upstream portion A and the midstream portion B starts the combustion operation in a three-stage state (see FIG. 6C). ), Flowing in the downstream part C. Therefore, this hot water is heated relatively large in the upstream part A and the middle stream part B, and is not heated greatly when flowing in the downstream part C. That is, this hot and cold water is heated in the same manner as when heated in a three-stage state. Then, the hot water newly flowing into the primary heat exchanger 4 following this hot water is heated by the combustion operation in the three-stage state.

That is, hot water that has flowed into the primary heat exchanger 4 when heated in a four-stage state flows out of the primary heat exchanger 4, and then the hot water that has flowed into the primary heat exchanger 4 has a three-stage state. It will be heated by. Therefore, from the primary heat exchanger 4, the hot water heated in the four-stage state and the hot water heated in the three-stage state are continuously discharged.
Here, as described above, in the hot water supply apparatus 1 of the present embodiment, the amount of combustion when the number of combustion stages is four stages and the combustion when there are three stages are adjusted by adjusting the opening of the gas proportional valve 37. The quantity can be the same combustion quantity. Therefore, when the switching is performed in the order of the four-stage state, the five-stage state of switching operation, and the three-stage state, the combustion amount temporarily increases in the five-stage state of switching operation. However, the tapping temperature does not fluctuate greatly. In other words, the amount of combustion at each number of combustion stages is adjusted by adjusting the opening degree of the gas proportional valve 37, and it is possible to prevent a significant fluctuation in the tapping temperature during the switching operation.

In the hot water supply apparatus 1 of the present embodiment, between the combustion operation in the four stages that is the number of stages before the change and the combustion operation in the three stages that is the number of stages after the change, the combustion operation in the five stages that is the operation between switching is performed. We are carrying out. In other words, in the hot water supply apparatus 1 of the present embodiment, when switching to the number of stages where the combustion amount decreases compared to the previous number of stages, the switching is temporarily performed to the number of stages where the combustion amount increases compared to the previous number of stages. doing. Further, when switching to the number of stages where the combustion amount increases, a flame is formed in the state of 4 stages, which is the stage number before switching, and in a combustion region where no flame is formed in the state of 3 stages, which is the stage number after switching. A state in which a flame is formed in a certain downstream combustion region γ is maintained.
For this reason, hot water is greatly heated in the downstream portion C of the primary heat exchanger 4, which is a portion that is not largely combusted in the three-stage state that is the number of stages after switching, only immediately after the switching operation. Therefore, there is no temporary shortage of hot water heating due to the change in the number of stages, and there is no large undershoot that hot water having a temperature much lower than the target temperature is discharged from the primary heat exchanger 4. .

  Above, the description about the outline | summary of the operation | movement between switching which the hot water supply apparatus 1 of this embodiment implements is complete | finished. Subsequently, a change in the number of stages of the combustion operation in the hot water supply apparatus 1 of the present embodiment, and an operation during switching performed in accordance with the change in the number of stages will be described in detail with reference to FIG.

In the hot water supply apparatus 1 of the present embodiment, when the required hot water flow rate or set temperature is changed and it is necessary to change the number of stages of the combustion operation, it is determined whether or not the switching satisfies a predetermined condition (step 1). .
Specifically, in the present embodiment, the predetermined number of stages (four stages) is switched to a specific number of stages (three stages) in which the combustion amount is reduced from the predetermined number of stages (four stages). If the number of stages immediately before performing the combustion operation at the number of stages (4 stages) is not the number of stages (5 stages) having a combustion amount larger than the predetermined stage number (4 stages), it is determined that the switching satisfies the predetermined condition ( It is determined that the answer is Yes in Step 1).

That is, when the combustion operation has been carried out with a number of stages (5 stages) having a combustion amount larger than the predetermined number of stages (4 stages) before, the can (primary heat exchanger 4 or primary heat exchanger 4 and secondary Other members such as the heat exchanger 5 are integrally formed, and it is predicted that the temperature of the square tube portion (combustion gas flow path) is high. And when the temperature of a can body is high, if the operation | movement between switching which implements combustion operation in the state whose combustion amount is higher than the number of previous stages is performed, there is a possibility that the combustion amount becomes temporarily excessive. That is, there is a possibility that a state (so-called overshoot) in which hot water having a temperature much higher than the target temperature is discharged due to a temporary excess of the combustion amount may occur.
Therefore, when the temperature of the can body is high (when the temperature of the can body is predicted to be high), the operation between the switches is not performed.

  At this time, if it is not switching that satisfies a predetermined condition (No in step 1), the number of stages is switched without performing the operation between switching (step 6).

  On the other hand, if it is the switching which satisfy | fills a predetermined condition (If it is Yes at step 1), the operation | movement between switching will be implemented (step 2). That is, when switching from a predetermined number of stages (four in this embodiment) to a specific number of stages (three in this embodiment), the number of stages having a larger combustion amount than the number of stages before switching (four in this embodiment). The combustion operation is performed in (in this embodiment, five stages).

Here, if the number of post-switching stages previously determined is changed from the specific number of stages (three in this embodiment) during the inter-switch operation, the inter-switch operation is interrupted. (Forcibly end) (step 5) and switch to the changed number of steps (step 6).
Specifically, for example, when switching the number of stages from a predetermined number of stages (four in the present embodiment) to a specific number of stages (three in the present embodiment), the operation between switching is performed before the switching of the number of stages. Suppose. Then, it is assumed that the hot water flow rate, the set temperature, and the like are changed during the operation during switching, and it is necessary to perform the combustion operation in, for example, five stages. In this case, the hot water supply device 1 stops the operation during switching, and performs the operation of switching to a five-stage state.
As described above, in the hot water supply device 1 of the present embodiment, a situation in which the operation between the switching is not required during the operation between the switching, that is, a situation in which a large undershoot is unlikely to occur even when the number of stages is switched. When it becomes, it becomes the structure which interrupts implementation of operation between switching. With such a configuration, the operation between the switching operations can be performed only when there is a high possibility that a large undershoot will occur at the time of switching the number of stages, so that the hot water supply device 1 can be operated efficiently.

  Then, after the switching operation is started, the number of stages after switching is not changed from the specific number of stages (in this embodiment, 3 stages) (in the case of Nо in Step 3), and a predetermined time t (for example, 1 second) has elapsed. Then (Yes in step 4), the inter-switching operation is terminated (step 5), and switching to a predetermined number of stages (three stages in the present embodiment) is performed (step 6). And the change of the number of stages of combustion operation is completed.

  In the above-described embodiment, an example in which the switching operation is performed only for a predetermined time t (for example, 1 second) predetermined by an experiment or the like has been described. That is, an example in which the operation during switching is performed only for the time necessary for the hot water that has not been heated significantly in the upstream portion A before the change in the number of stages to flow out of the primary heat exchanger 4 after being heated in the downstream portion C. Indicated. However, the switching operation of the present invention is not limited to this. For example, the operation during switching may be performed based on the flow rate of hot water obtained by the incoming water flow rate sensor 47. Specifically, the amount of water flowing into the water inlet pipe 43 (or the primary heat exchanger 4) is acquired from the value acquired by the water inlet flow sensor 47 by calculation or the like, and the operation between the switching operations is terminated based on the acquired value of the water flow amount. The operation may be performed. That is, the operation for ending the inter-switching operation may be performed on the condition that the water flow amount after the inter-switching operation is started is equal to or greater than a predetermined amount.

  In the above-described embodiment, each of the three burner groups (the first burner group 15, the second burner group 16, the third burner group 17) is composed of a plurality of burners. It is not limited. The burner group may be composed of a single burner. That is, one burner itself may be a burner group.

  In the above-described embodiment, three burner groups (second burner) each composed of a plurality of burners having different numbers in three combustion regions (upstream combustion region α, midstream combustion region β, and downstream combustion region γ). Although the example in which the group 16, the first burner group 15, and the third burner group 17) are arranged is shown, the heat source apparatus of the present invention is not limited to this. The structure which distribute | arranges the burner from which a magnitude | size and the maximum combustion amount differ in three combustion areas, respectively may be sufficient.

In the above-described embodiment, the flame forming portion is divided into three combustion regions, and the combustion amount in the downstream combustion region γ located on the most downstream side in the overall hot water flow direction of the primary heat exchanger 4 is the largest, The combustion amount in the midstream combustion region β located between the upstream combustion region α and the downstream combustion region γ is set to be the smallest. In such a configuration (arrangement state of the combustion region), when the above-described combustion operation with different number of stages is continuously performed to reduce the combustion amount, a large undershoot is remarkably generated.
However, in the hot water supply device 1 of the present embodiment, when performing the combustion operation with different number of stages to reduce the combustion amount, the combustion operation with the number of stages before the change and the combustion operation with the number of stages after the change are performed. Perform the switching operation. For this reason, in the hot water supply apparatus 1 of the present embodiment, even when the arrangement of the combustion region in which a large undershoot is remarkably generated is employed, a large undershoot does not occur.

In the above-described embodiment, an example in which the flame forming unit is divided into three combustion regions has been shown, but the heat source apparatus of the present invention is not limited to this. The flame forming part may be divided into two combustion regions, or may be divided into four or more combustion regions. That is, the flame formation part should just be divided | segmented into the some combustion area | region. More specifically, a plurality of divided combustion regions include one combustion region (also referred to as a combustion region γ2) located downstream of the overall hot water flow direction of the primary heat exchanger 4, and the combustion region γ2. Also, it is only necessary to include two combustion regions, one combustion region (also referred to as combustion region α2) on the upstream side. Of the plurality of divided combustion regions, which combustion region is set as the downstream combustion region γ2 and the upstream combustion region α2 may be appropriately changed. It suffices if there is an upstream combustion region α2 upstream of the downstream combustion region γ2. Further, the combustion region α2 and the combustion region γ2 do not have to be adjacent to each other. That is, the combustion region α2 and the combustion region γ2 may be arranged at an interval.
Then, from the state where the flame is formed in the downstream combustion region γ2 and the flame is not formed in the upstream combustion region α2, no flame is formed in the downstream combustion region γ2, and in the upstream combustion region α2. When switching to a state in which a flame is formed, an operation during switching that maintains a state in which a flame is formed in the downstream combustion region γ2 may be performed.

1 Water heater (heat source machine)
4 Primary heat exchanger (heat exchanger)
25 Flowing water pipe (liquid flow path)
35 Fuel supply pipe (fuel supply path)
α Upstream combustion zone γ Downstream combustion zone

Claims (3)

A flame forming section, a fuel supply path, and a heat exchanger;
The heat exchanger includes a liquid flow path through which liquid can be circulated, and heat exchange is performed between the liquid flowing through the liquid flow path and the combustion gas generated when the flame forming unit burns fuel. And
The flame forming section is partitioned into a plurality of combustion regions corresponding to the overall hot water flow direction of the heat exchanger,
Flames can be formed individually in each combustion region, and switching to increase or decrease the combustion region forming the flame is possible,
The plurality of combustion areas include a downstream combustion area corresponding to the downstream side of the liquid flow path, an upstream combustion area corresponding to the upstream side of the liquid flow path, the upstream combustion area, and the downstream combustion area. Including a midstream combustion region located between
A state in which no flame is formed in the downstream combustion region from a state in which a flame is formed in the downstream combustion region and the midstream combustion region, and a flame is generated in the midstream combustion region and the upstream combustion region. When switching to a state that forms
A heat source machine that performs an operation during switching that maintains a state in which a flame is formed in the upstream combustion region, the midstream combustion region, and the downstream combustion region . The heat source apparatus according to claim 1, wherein the switching operation is continuously performed for a predetermined time. The heat source machine according to claim 1, wherein the operation during switching is terminated on condition that a water flow amount of a predetermined amount or more is detected.

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