JP7353125B2 - heat source machine - Google Patents

Description

The present invention relates to a heat source device equipped with a heat exchanger in which heat transfer tubes are provided in one stage, and in which burner blocks for combustion are switched depending on the amount of combustion.

In water heaters that serve as heat sources, there is a known technology in which the burner is divided into multiple burner blocks and the burner block used for combustion is switched in order to ensure the optimum combustion amount from the minimum combustion amount to the maximum combustion amount. There is. For example, when changing the burner block, if the combustion amount is to be increased or decreased by one step, the standard switching is performed in ascending or descending order of the combustion amount, and if the combustion amount is to be increased or decreased by two or more steps, the burner block is switched in a predetermined order with a shortened switching time. A device that performs special switching is known (Patent Document 1).

JP2006-329548A

In the above-mentioned water heaters, in those equipped with a heat exchanger in which heat transfer tubes for flowing hot water are arranged in one stage, overshoot or undershoot of the hot water temperature may occur due to switching of the burner block used for combustion. . For example, if hot water that was heated by the burner block before switching is heated again by the burner block to which the switch is being made, an overshoot in the hot water temperature may occur immediately after the burner block is switched, and hot water at a higher temperature may be drawn. was there. In addition, if the water that was not heated in the burner block before switching is hardly heated in the burner block to which the switch is being made, there is a risk that undershoot of the hot water temperature will occur immediately after switching the burner block, and hot water at a lower temperature will be drawn out. was there.

The present invention has been made in view of the above circumstances, and in a heat source equipment equipped with a heat exchanger in which heat transfer tubes are provided in one stage, the hot water outlet temperature overshoots or undershoots even if the burner block for combustion is switched. The purpose of the present invention is to provide a heat source device that can suppress

The heat source device according to the present invention includes:
a heat exchanger in which a heat exchanger tube through which a fluid heated by the combustion exhaust gas flows is arranged in a single stage in the direction of flow of the combustion exhaust gas in the body through which the combustion exhaust gas flows;
A burner that generates combustion exhaust gas is arranged to face the heat exchanger tube of the heat exchanger, and the burner is divided into a plurality of burner blocks and arranged in parallel along the direction from the water supply inlet to the hot water outlet of the heat exchanger tube. a combustion section,
burner switching means for switching burner blocks to be burned according to the amount of combustion;
When the burner switching condition is met , in which the burner block is switched from the burner block closer to the water supply inlet side of the heat transfer tube to the burner block closer to the hot water outlet side of the heat transfer tube , the burner block is switched to the burner block that lowers the combustion amount. In a first embodiment including a control unit capable of performing burner switching processing via switching,
The control unit includes:
Executing the burner switching process when the amount of change in the flow rate of the fluid supplied to the heat transfer tubes immediately before the burner switching condition is satisfied is less than a predetermined flow rate value,
When the amount of change in flow rate increases to more than the predetermined flow rate value, the burner block is immediately switched to a burner block closer to the hot water outlet side of the heat transfer tube.

If the heat exchanger has heat transfer tubes arranged in one stage and the burner block is switched from the burner block near the water supply inlet side of the heat transfer tubes to the burner block near the hot water outlet side of the heat transfer tubes, There is a possibility that the fluid heated in the burner block before switching is heated again in the burner block to be switched, resulting in overshoot.
However, according to the configuration of the present invention, by once switching to the burner block whose combustion rate is lowered, the fluid heated by the burner block before switching is hardly heated by the burner block whose combustion rate is lowered. Since it flows out without being heated, reheating by switching the burner block is suppressed. Therefore, it is possible to suppress overshoot of the tapping temperature immediately after switching the burner block. As a result, the user does not feel uncomfortable due to being supplied with high temperature fluid immediately after switching the burner block, and a heat source device that is easy to use can be obtained.
Burner block switching may be accomplished by changing the fluid flow rate supplied to the heat transfer tubes. If the flow rate change is small, less than the predetermined flow rate value, when the burner block is switched from the burner block closer to the water supply inlet side of the heat exchanger tube to the burner block closer to the hot water outlet side of the heat exchanger tube, at the time of switching, The amount of reheating of the fluid increases near the hot water outlet side of the heat transfer tube. Therefore, there is a possibility that the overshoot of the outlet temperature will become large immediately after the burner block is switched.
However, according to the configuration of the present invention, by executing the burner switching process to temporarily lower the combustion amount when the flow rate change amount is less than a predetermined flow rate value, the temperature of the tapped water is prevented from overshooting immediately after the burner block is switched. Shoots can be appropriately suppressed.
On the other hand, when the flow rate change amount increases to a predetermined flow rate value or more, the burner block is immediately switched to the burner block closer to the hot water outlet side of the heat transfer tube. In this case, the flow rate of the fluid flowing inside the heat transfer tube increases significantly compared to before the change, so even if it is heated again near the hot water exit of the heat transfer tube, the temperature of the fluid will not rise and a large overshoot of the hot water temperature will not occur. Furthermore, since the heat exchanger tube is reheated in the vicinity of the hot water exit, even if the flow rate of the fluid in the heat exchanger tube increases, undershoot of the hot water temperature can be suppressed.

Furthermore, the heat source device according to the present invention includes:
a heat exchanger in which a heat exchanger tube through which a fluid heated by the combustion exhaust gas flows is arranged in a single stage in the direction of flow of the combustion exhaust gas in a body through which the combustion exhaust gas flows;
A burner that generates combustion exhaust gas is arranged to face the heat exchanger tube of the heat exchanger, and the burner is divided into a plurality of burner blocks and arranged in parallel along the direction from the water supply inlet to the hot water outlet of the heat exchanger tube. a combustion section,
burner switching means for switching burner blocks to be burned according to the amount of combustion;
If the burner switching condition is met , in which the burner block is switched from the burner block closer to the hot water outlet side of the heat transfer tube to the burner block closer to the water supply inlet side of the heat transfer tube , the burner block should be switched once to increase the combustion amount. In a second embodiment including a control unit capable of performing burner switching processing via switching,
The control unit includes:
Executing the burner switching process when the amount of change in the flow rate of the fluid supplied to the heat transfer tubes immediately before the burner switching condition is satisfied is less than a predetermined flow rate value,
When the flow rate change amount increases to a predetermined flow rate value or more, the burner block is immediately switched to a burner block closer to the water supply inlet side of the heat transfer tube.

If the heat exchanger has heat transfer tubes arranged in one stage and the burner block is switched from the burner block near the hot water outlet side of the heat transfer tubes to the burner block near the water supply inlet side of the heat transfer tubes, There is a risk that undershoot may occur because the fluid that was not heated in the burner block before switching is hardly heated in the burner block to which switching is performed.
However, according to the configuration of the present invention, by once switching to a burner block that increases the combustion amount, the fluid that was not heated in the burner block before switching is transferred to the burner block that has increased the combustion amount. Since the burner block is heated by switching the burner block, it is suppressed that the burner block is hardly heated. Therefore, it is possible to suppress undershoot of the tapping temperature immediately after switching the burner block. As a result, the user does not feel uncomfortable due to being supplied with low-temperature fluid immediately after switching the burner block, and a heat source device that is easy to use can be obtained.

Burner block switching may be accomplished by changing the fluid flow rate supplied to the heat transfer tubes . If the flow rate change of the fluid is small, less than the predetermined flow rate value, the burner block is switched from the burner block closer to the hot water outlet side of the heat transfer tube to the burner block closer to the water supply inlet side of the heat transfer tube. At this time, the amount of heating of the fluid near the hot water outlet side of the heat transfer tube becomes small. Therefore, there is a possibility that the undershoot of the tapping temperature becomes large immediately after switching the burner block.
However, according to the configuration of the present invention, the burner switching process that once increases the combustion amount is performed when the amount of change in the flow rate of the fluid supplied to the heat transfer tube is less than a predetermined flow rate value, thereby increasing the burner block. Undershoot of the hot water temperature immediately after switching can be appropriately suppressed.
On the other hand, when the flow rate change amount increases to a predetermined flow rate value or more, the burner block is immediately switched to a burner block closer to the water supply inlet side of the heat exchanger tube. In this case, the fluid flow rate after the change greatly increases compared to the fluid flow rate before the change, and since the change to increase the fluid flow rate is made at the user's will, the temperature is temporarily lower immediately after switching. Even when the fluid is dispensed, the user hardly feels any discomfort.

Furthermore, the heat source device according to the present invention includes:
In the first form described above,
The control unit includes:
Executing the burner switching process when the amount of temperature change in the hot water setting temperature immediately before the burner switching condition is satisfied is less than a predetermined temperature value,
When the temperature change amount reaches a high temperature equal to or higher than the predetermined temperature value, the heat source device immediately switches to a burner block near the hot water outlet side of the heat transfer tube,
Moreover, in the above-mentioned second form,
The control unit includes:
Executing the burner switching process when the amount of temperature change in the hot water setting temperature immediately before the burner switching condition is satisfied is less than a predetermined temperature value,
When the temperature change amount becomes higher than the predetermined temperature value, the heat source device immediately switches to a burner block closer to the water supply inlet side of the heat transfer tube.
Switching of burner blocks may be performed by changing the hot water temperature setting. As mentioned above, if the burner block is switched between the burner block near the water supply inlet side of the heat transfer tube and the burner block near the hot water outlet side of the heat transfer tube, an overshoot or an overshoot in the outlet temperature may occur immediately after the burner block switchover. Undershoot may occur. In this case, if the amount of temperature change in the hot water tap temperature is small and is less than the predetermined temperature value, it will be equivalent to a small change in flow rate even when compared with the changed hot water tap temperature setting, and overshoot or undershoot of the hot water tap temperature will occur. big. Therefore, by executing the burner switching process when the amount of change in the set hot water outlet temperature is less than a predetermined temperature value, it is possible to appropriately suppress overshoot or undershoot of the hot water outlet temperature immediately after switching the burner block.
On the other hand, if the temperature change amount is higher than the predetermined temperature value, even if the burner switching is not performed, in the first embodiment, an overshoot of the hot water outlet temperature higher than the newly set hot water set temperature is achieved. In addition, in the second embodiment, even if a fluid with a low temperature is temporarily dispensed immediately after the burner is switched, the hot water set temperature before the change is considerably lower than the hot water set temperature after the change. Therefore, the user rarely feels discomfort.

1 is a schematic diagram showing the configuration of a water heater according to Embodiment 1. FIG. 1 is a schematic diagram showing the configuration of heat exchanger tubes of a heat exchanger in Embodiment 1. FIG. 5 is a flowchart showing the operation of burner switching processing executed by the water heater according to the first embodiment. FIG. 2 is a schematic diagram showing the configuration of a water heater according to a second embodiment. 7 is a flowchart showing the operation of burner switching processing executed by the water heater according to the second embodiment.

Embodiments of the present invention will be described below.
(Embodiment 1)
Embodiment 1 of the present invention is a water heater as a heat source device. As shown in FIG. 1, this water heater 1A includes a heat exchanger 2, a combustion section 3, and a control section 4.

The heat exchanger 2 includes a rectangular box-shaped body 21 and heat transfer tubes 22 disposed within the body 21. The combustion exhaust gas from the combustion section 3 is passed through the body 21, and the water (fluid) flowing through the heat transfer tubes 22 is heated by the combustion exhaust gas. The heat exchanger tubes 22 are arranged in one step in the direction of flow of combustion exhaust gas within the body 21 . As shown in FIG. 2(a), the heat transfer tubes 22 meander in a reciprocating manner between the front side wall 21a and the rear side wall 21b of the body 21, and connect the right side wall 21c and the left side wall 21d of the body 21. It has been extended over a period of time. Note that the meandering of the heat exchanger tubes 22 may be configured to be connected to communication tubes 28 provided on the outer surface of the front wall 21a and the outer surface of the rear wall 21b, respectively, as shown in FIG. 2(b).

In addition, the heat transfer tube 22 has a water supply inlet 22a, which is one end of the pipe, connected to the right side wall 21c of the body 21, and a hot water outlet 22b, which is the other pipe end, is connected to the left side wall 21d of the body 21. . Note that one or both of the water supply inlet 22a and hot water outlet 22b of the heat transfer tube 22 may be connected to the front wall 21a or the rear wall 21b of the body 21 (see FIGS. 2(b) and 2(c)). On the outer surface of the body 21, a water supply pipe 23 is connected to the water supply inlet 22a of the heat exchanger tube 22 provided on the right side wall 21c of the body 21, and a hot water outlet pipe 24 is connected to the hot water outlet of the heat exchanger tube 22 provided on the left side wall 21d of the body 21. It is connected to the outlet 22b. The water supply pipe 23 is provided with a flow rate sensor 25 that detects the flow rate of water flowing into the water supply pipe 23 . A bypass pipe 26 is connected in communication between the water supply pipe 23 and the hot water outlet pipe 24.

In this water heater 1A, the water supplied from the water supply pipe 23 to the heat transfer pipe 22 is heated by the combustion exhaust gas from the combustion section 3 and is supplied to the hot water outlet pipe 24, and the water supplied from the bypass pipe 26 to the water supply pipe 23 is By supplying a portion of the hot water to the hot water outlet pipe 24 via the bypass valve 27, a hot water supply circuit is configured to supply hot water adjusted to the hot water outlet temperature to a hot water user downstream of the hot water outlet pipe 24.

The combustion section 3 has a rectangular box-shaped combustion box 31 connected to the lower part of the body 21 of the heat exchanger 2, and a burner 32 that generates combustion exhaust gas in the combustion box 31 is connected to the heat exchanger tube of the heat exchanger 2. It is arranged opposite to 22. A fan 33 that supplies combustion air to the burner 32 is connected to the bottom plate of the combustion box 31 . The burner 32 is arranged in a plurality of first to third burner blocks 32a, 32b, 32c along the direction from the water supply inlet 22a, which is one pipe end of the heat transfer tube 22, to the hot water outlet 22b, which is the other pipe end. It is divided into two and placed side by side. That is, the plurality of burner blocks 32a, 32b, and 32c are arranged in parallel from the upstream side to the downstream side of the flow of hot water with respect to the heat transfer tube 22.

A gas supply pipe 34 for supplying fuel gas is connected to the burner 32, and the gas supply pipe 34 includes a former solenoid valve 35, a proportional valve 36, and a switching valve 37 (burner switching means) is provided. The switching valve 37 includes first to third switching valves 37a, 37b, and 37c for each burner block 32a, 32b, and 32c. Note that the number of divisions of the burner block and the corresponding number of switching valves 37 are not limited to the above three, and three or more may be provided.

In this water heater 1A, fuel gas is supplied to the burner 32 from the gas supply pipe 34, and combustion air is supplied from the fan 33, and a combustion operation is performed according to a predetermined sequence. At this time, in the burner 32, the burner blocks 32a, 32b, and 32c are switched between the first to third burner blocks 32a, 32b, and 32c to achieve the optimum combustion amount based on the water supply flow rate in the water supply pipe 23, hot water setting temperature, incoming water temperature, etc. Burner switching processing is performed using valves 37a, 37b, and 37c. The operation of this burner switching process is performed by a command from the control unit 4 provided in the water heater 1A.

In the first embodiment, the combustion amount of the burner 32 has five combustion modes: small combustion, medium-small combustion, medium combustion, medium-large combustion, and large combustion, as shown by the dotted line in FIG. In the case of small combustion, only the first switching valve 37a is opened and only the first burner block 32a is combusted. In the case of small to medium combustion, only the second switching valve 37b is opened and only the second burner block 32b is burned. In the case of medium combustion, the third switching valve 37c is closed, the first switching valve 37a and the second switching valve 37b are opened, and the first burner block 32a and the second burner block 32b are combusted. In the case of medium-large combustion, the second switching valve 37b is closed, the first switching valve 37a and the third switching valve 37c are opened, and the first burner block 32a and the third burner block 32c are combusted. In the case of large combustion, all the first to third switching valves 37a, 37b, 37c are opened, and all the first to third burner blocks 32a, 32b, 32c are combusted. From this, in the first embodiment, in the case of small combustion, medium-small combustion, and medium combustion, combustion is performed in the second and first burner blocks 32b, 32a near the water supply inlet 22a side of the heat transfer tube 22, and in the case of medium-large combustion. In this case, combustion is performed in the third and first burner blocks 32c and 32a close to the hot water outlet 22b side of the heat transfer tube 22.

Next, the burner switching processing operation by the control section 4 will be explained. Below, as an example, a case will be described in which burner switching is performed to increase the combustion amount from medium combustion to medium-large combustion.
As shown in the flowchart of FIG. 3, when burner combustion is started in medium combustion (step S1), storage of water supply flow rate data in the water supply pipe 23 is started (step S2). The water supply flow rate data is stored as the water supply flow rate at a predetermined data acquisition time (for example, 5 seconds at all times). If the conditions for burner switching are satisfied during this medium combustion ("YES" in step S3), the operation moves to step S4. As a burner 32 switching condition, for example, due to changes in the water supply flow rate in the water supply pipe 23, the hot water outlet temperature setting, the incoming water temperature, etc., the current combustion amount (for example, medium combustion) does not produce hot water at the desired hot water outlet temperature. This is the case when it becomes impossible to do so.

In step S4, it is determined whether or not the state of intermediate combustion is longer than a predetermined residence time t after starting the intermediate combustion. This residence time t can be matched with the data acquisition time of the water supply flow rate data, and in the first embodiment, it is set to, for example, 5 seconds. If the burner switching condition is satisfied before the medium combustion state reaches the stay time t ("NO" in step S4), the burner is immediately switched to medium and large combustion (step S8). In this case, since the state of medium combustion continues for only a very short time (for example, less than 5 seconds), the water near the water supply inlet 22a that has flowed into the heat exchanger tube 22 is transferred to the second tank near the water supply inlet 22a. , the first burner blocks 32b and 32a are not yet sufficiently heated. Therefore, burner combustion can be switched directly from the second and first burner blocks 32b, 32a close to the water supply inlet 22a side to the third and first burner blocks 32c, 32a close to the hot water outlet 22b side to perform medium-to-large combustion. Therefore, even if the vicinity of the hot water outlet 22b of the heat transfer tube 22 is heated again, a large overshoot in the hot water temperature does not occur.

If the medium combustion state is longer than the predetermined residence time t in step S4 ("YES" in step S4), the operation moves to the next step S5. In step S5, it is determined whether the amount of change in the water supply flow rate is less than a predetermined flow rate value ΔQ (for example, 4.5 L/min). This amount of change in flow rate is determined as the difference between the maximum water supply flow rate value and the minimum water supply flow rate value at the most recent data acquisition time stored in step S2. In this first embodiment, since the combustion amount is switched from medium combustion to medium-large combustion, this is a case where the water supply flow rate is increased. If the amount of change in flow rate is equal to or greater than the predetermined flow rate value ΔQ (“NO” in step S5), the burner is immediately switched to medium-large combustion (step S8). In this case, since the flow rate of hot water flowing inside the heat transfer tube 22 increases greatly compared to before the change, the second and first burner blocks 32b, 32a, which are close to the water supply inlet 22a side, are directly connected to the third burner block, which is close to the hot water outlet 22b side. By switching the burner combustion to the first burner blocks 32c and 32a and performing medium-large combustion, even if the hot water is heated again near the outlet 22b of the heat transfer tube 22, the temperature of the hot water does not rise much and a large overshoot of the outlet temperature occurs. There's nothing to do. Further, since the hot water is heated again near the hot water outlet 22b of the heat transfer tube 22, even if the flow rate of hot water in the heat transfer tube 22 increases, undershoot of the hot water temperature can be suppressed.

If the amount of change in the water supply flow rate is less than the predetermined flow rate value ΔQ in step S5 (“YES” in step S5), the operation proceeds to step S6. In step S6, it is determined whether the amount of temperature change in the hot water installation temperature is less than a predetermined temperature value ΔT (for example, 6° C.). The amount of change in hot water setting temperature is the temperature difference before and after the user changes the current hot water tap temperature setting to a new hot water tap temperature setting using a remote control or the like. In this first embodiment, since the combustion amount is switched from medium combustion to medium-large combustion, this is a case where the hot water outlet temperature setting is changed to a higher temperature than the current temperature. If the set temperature change amount for hot water is equal to or greater than the predetermined temperature value ΔT (“NO” in step S6), the burner is immediately switched to medium-large combustion (step S8). In this case, the hot water tap temperature is set higher than before the change, so the second and first burner blocks 32b, 32a, which are closer to the water supply inlet 22a side, directly direct the third and first burner blocks 32c, which are closer to the hot water outlet 22b side. , 32a to perform medium-large combustion, an overshoot of the outlet temperature higher than the newly set outlet temperature will occur even if the area near the outlet 22b of the heat transfer tube 22 is heated again. Nor.

If the amount of temperature change in the set hot water tap temperature is less than the predetermined temperature value ΔQ in step S6 ("YES" in step S6), the operation proceeds to step S7. In step S7, the burner is switched from medium combustion to small combustion. After performing this small combustion for a short period of time (for example, 1.5 seconds), the burner is switched to medium and large combustion, which is the target combustion amount (step S8), and the present process ends.

The burner switching process performed in step S7 is performed from the second and first burner blocks 32b, 32a (medium combustion) near the water supply inlet 22a side of the heat transfer tube 22 to the third and first burner blocks near the hot water outlet 22b side of the heat transfer tube 22. When switching to blocks 32c and 32a (medium-large combustion), if the amount of change in the feed water flow rate is small and the amount of change in the outlet temperature setting is small, the first step is to temporarily lower the combustion amount than the combustion amount before switching (medium combustion). It goes through switching to burner block 32a (small combustion). In this way, when switching the combustion amount from medium combustion to medium-large combustion, by passing through small combustion once, the second and first burner blocks 32b near the water supply port 22a side of the heat transfer tube 22 during medium combustion. , 32a is suppressed from being heated again by the third and first burner blocks 32c, 32a, which are close to the hot water outlet 22b side of the heat transfer tube 22, which is the intended switching destination. . Therefore, it is possible to suppress overshoot of the tapping temperature immediately after switching the burner block. As a result, the user does not feel uncomfortable because hot water at a high temperature is supplied immediately after switching the burner at the hot water usage site, and the hot water supply device 1A is easy to use.

Further, according to the first embodiment, the burner block configuration shown in FIG. When switching, the combustion amount is lower than the medium combustion before switching, and by passing through the small combustion (combustion in the first burner block 32a adjacent to the third burner block 32c) instead of the medium and small combustion, the combustion amount is lower than the medium combustion before switching. Fire can be smoothly transferred to the three-burner block 32c.

Note that the burner switching process in Embodiment 1 does not include switching from small combustion (minimum combustion amount), and when switching from medium combustion to large combustion, and when switching from small and medium combustion to medium and large combustion or large combustion, The burner switching process shown in FIG. 3 can be applied.

(Embodiment 2)
As shown in FIG. 4, in the water heater 1B of the second embodiment, the water supply pipe 23 and the hot water outlet pipe 24 connected to the heat exchanger 2 are connected in the opposite way to the water heater 1A of FIG. be. That is, the water supply inlet 22a, which is one pipe end of the heat exchanger tube 22, is connected to the left side wall 21d of the body 21, and the hot water outlet 22b, which is the other pipe end of the heat exchanger tube 22, is connected to the right side wall 21c of the body 21. has been done. On the outside of the body 21, the water supply pipe 23 is connected to the water supply inlet 22a of the heat exchanger tube 22 provided on the left side wall 21d of the body 21, and the hot water outlet pipe 24 is connected to the hot water outlet 22b of the heat exchanger tube 22 provided on the right side wall 21c of the body 21. It is connected to the. Therefore, in the second embodiment, in the case of small combustion, medium-small combustion, and medium combustion, combustion is performed in the second and first burner blocks 32b, 32a close to the hot water outlet 22b side of the heat transfer tube 22, and in the case of medium-large combustion. In this case, combustion is performed in the third and first burner blocks 32c and 32a close to the water supply inlet 22a side of the heat transfer tube 22. The other configurations are the same as the water heater 1A in FIG.

Further, in the second embodiment, when the burner switching process by the control unit 4 is to perform burner switching to increase the combustion amount from medium combustion to medium-large combustion, for example, the process according to the flowchart of FIG. 5 is performed. The flowchart in FIG. 5 corresponds to the flowchart in FIG. 3 in the first embodiment, but in step S7 of the flowchart in FIG. 3, the burner is switched to small combustion, whereas in step S17 in the flowchart in FIG. Switch the burner to combustion. That is, in the second embodiment, the burner blocks are switched from the second and first burner blocks 32b, 32a (medium combustion) near the hot water outlet 22b side of the heat transfer tube 22 to the third burner block near the water supply inlet 22a side of the heat transfer tube 22. , when switching to the first burner blocks 32c, 32a (medium-large combustion), the first to third burner blocks 32a, 32b temporarily increase the combustion amount compared to the combustion amount after switching when certain conditions are satisfied. , 32c (large combustion).

The above-mentioned constant condition is when the amount of change in the flow rate of the water supply flow rate is small (less than the predetermined flow rate value ΔQ) and the amount of temperature change in the set hot water temperature is small (less than the predetermined temperature value ΔT), and in this case, immediately after the burner block is switched. If an undershoot in the hot water temperature temporarily occurs and hot water at a low temperature is discharged, the user may feel uncomfortable. However, as described above, when switching the combustion amount from medium combustion (combustion of the first and second burner blocks 32a and 32b) to medium and large combustion (combustion of the first and third burner blocks 32a and 32c), By passing through the large combustion (combustion of all the first to third burner blocks 32a, 32b, 32c), the second and first burner blocks 32b near the hot water outlet 22b side of the heat transfer tube 22 during medium combustion. , 32a, the hot water in the heat transfer tube 22, which was supposed to be heated by the hot water outlet 22b, is prevented from being tapped out without being heated due to the combustion stop of the second burner block 32b on the hot water outlet 22b side due to the burner switching. Ru. Therefore, it is possible to suppress undershoot of the tapping temperature immediately after switching the burner block. As a result, the user does not feel uncomfortable because hot water at a low temperature is supplied immediately after switching the burner block at the hot water usage site, and the water heater 1 is easy to use.

Note that steps S14, S15, and S16 in the flowchart of FIG. 5 have the same operations as steps S4, S5, and S6 in the flowchart of FIG. 3, respectively, but the reason for transitioning to "NO" is different. That is, in the water heater 1B of the second embodiment shown in FIG. 4, the heat exchanger tubes 22 of the heat exchanger 2 are arranged in one step, and the burner block switching is close to the hot water outlet 22b side of the heat exchanger tubes 22. When switching from the second and first burner blocks 32b and 32a to the third and first burner blocks 32c and 32a that are closer to the water supply inlet 22a side of the heat transfer tube 22, the burner blocks (32b and 32a) before switching are used for heating. There is a risk that the hot water that is not heated will not be heated much in the burner blocks (32c, 32a) to which it is switched, and undershoot may occur. Therefore, in the process shown in the flowchart of FIG. 5 (Embodiment 2), the undershoot of the tapping temperature is mainly suppressed.

In step S14, if the burner switching condition is satisfied before the medium combustion state reaches the predetermined residence time t ("NO" in step S14), the burner is immediately switched to medium-large combustion (step S18). In this case, since the state of medium combustion continues for only a very short time (for example, less than 5 seconds), the water near the hot water outlet 22b in the heat transfer tube 22 is transferred to the second outlet near the hot water outlet 22b, It is not yet sufficiently heated by the first burner blocks 32b and 32a. Therefore, the burner combustion is switched directly from the second and first burner blocks 32b, 32a near the hot water outlet 22b side to the third and first burner blocks 32c, 32a near the water supply inlet 22a side. By performing combustion, even if the hot water is tapped out without being heated much near the hot water outlet 22b of the heat transfer tube 22, a large undershoot in the tapped water temperature does not occur.

In step S15, if the amount of change in the water supply flow rate is equal to or greater than the predetermined flow rate value ΔQ ("NO" in step S15), the burner is immediately switched to medium-large combustion (step S18). In this case, the water supply flow rate after the change is significantly increased compared to the water supply flow rate before the change, and the change to increase the water supply flow rate is made at the user's will. Therefore, the hot water that was not heated on the water supply inlet 22a side during medium combustion before switching the burner block performs medium and large combustion, so by switching the burner block, it is not heated much on the hot water outlet 22b side, and immediately after switching, Even if hot water is dispensed at a relatively low temperature, the user will not feel any discomfort since the water supply flow rate has increased significantly after the change.

In step S16, if the set temperature change amount for hot water is equal to or greater than the predetermined temperature value ΔT ("NO" in step S16), the burner is immediately switched to medium-large combustion (step S18). In this case, the hot water outlet temperature setting after the change is considerably higher than the hot water outlet temperature setting before the change, and the change to increase the hot water outlet temperature setting is made at the user's will. Therefore, the hot water that was not heated on the water supply inlet 22a side during medium combustion before switching the burner block performs medium and large combustion, so by switching the burner block, it is not heated much on the hot water outlet 22b side, and immediately after switching, Even if hot water is dispensed at a relatively low temperature, the user will not feel any discomfort since the preset hot water temperature before the change was quite low.

Note that the present invention is not limited to the above embodiments. In the embodiment, the combustion amount is increased to one higher combustion stage from medium combustion to medium-large combustion, but the present invention is applicable to the number of combustion stages to be switched, the case where the combustion amount is increased, the combustion amount is decreased, etc. It can be applied regardless. Furthermore, the present invention is applicable not only to single-function hot water heaters but also to various heat source devices such as bath water heaters and hot water heaters.

1A, 1B Water heater 2 Heat exchanger 3 Combustion section 4 Control section 21 Body 22 Heat exchanger tube 21a Front measurement wall 21b Rear wall 21c Right side wall 21d Left side wall 22a Water supply inlet 22b Hot water outlet 23 Water supply pipe 24 Hot water discharge pipe 25 Flow rate sensor 26 Bypass Pipe 27 Bypass valve 28 Communication pipe 31 Combustion box 32 Burner 33 Fan 32a First burner block 32b Second burner block 32c Third burner block 34 Gas supply pipe 35 Original solenoid valve 36 Proportional valve 37 Switching valve 37a First switching valve 37b 2 switching valve 37c 3rd switching valve

Claims (4)

a heat exchanger in which a heat exchanger tube through which a fluid heated by the combustion exhaust gas flows is arranged in a single stage in the direction of flow of the combustion exhaust gas in the body through which the combustion exhaust gas flows;
A burner that generates combustion exhaust gas is arranged to face the heat exchanger tube of the heat exchanger, and the burner is divided into a plurality of burner blocks and arranged in parallel along the direction from the water supply inlet to the hot water outlet of the heat exchanger tube. a combustion section,
burner switching means for switching burner blocks to be burned according to the amount of combustion;
When the burner switching condition is met , in which the burner block is switched from the burner block closer to the water supply inlet side of the heat transfer tube to the burner block closer to the hot water outlet side of the heat transfer tube , the burner block is switched to the burner block that lowers the combustion amount. Equipped with a control unit that can perform burner switching processing via switching ,
The control unit includes:
Executing the burner switching process when the amount of change in the flow rate of the fluid supplied to the heat transfer tubes immediately before the burner switching condition is satisfied is less than a predetermined flow rate value,
When the flow rate change amount increases to the predetermined flow rate value or more, the heat source device immediately switches to a burner block closer to the hot water outlet side of the heat transfer tube. a heat exchanger in which a heat exchanger tube through which a fluid heated by the combustion exhaust gas flows is arranged in a single stage in the direction of flow of the combustion exhaust gas in a body through which the combustion exhaust gas flows;
A burner that generates combustion exhaust gas is arranged to face the heat exchanger tube of the heat exchanger, and the burner is divided into a plurality of burner blocks and arranged in parallel along the direction from the water supply inlet to the hot water outlet of the heat exchanger tube. a combustion section,
burner switching means for switching burner blocks to be burned according to the amount of combustion;
If the burner switching condition is met , in which the burner block is switched from the burner block closer to the hot water outlet side of the heat transfer tube to the burner block closer to the water supply inlet side of the heat transfer tube , the burner block should be switched once to increase the combustion amount. Equipped with a control unit that can perform burner switching processing via switching ,
The control unit includes:
Executing the burner switching process when the amount of change in the flow rate of the fluid supplied to the heat transfer tubes immediately before the burner switching condition is satisfied is less than a predetermined flow rate value,
When the flow rate change amount increases to a predetermined flow rate value or more, the heat source device immediately switches to a burner block closer to the water supply inlet side of the heat transfer tube. a heat exchanger in which a heat exchanger tube through which a fluid heated by the combustion exhaust gas flows is arranged in a single stage in the direction of flow of the combustion exhaust gas in the body through which the combustion exhaust gas flows;
A burner that generates combustion exhaust gas is arranged to face the heat exchanger tube of the heat exchanger, and the burner is divided into a plurality of burner blocks and arranged in parallel along the direction from the water supply inlet to the hot water outlet of the heat exchanger tube. a combustion section,
burner switching means for switching burner blocks to be burned according to the amount of combustion;
If the burner switching conditions are met, in which the burner block is switched from the burner block closer to the water supply inlet side of the heat transfer tube to the burner block closer to the hot water outlet side of the heat transfer tube, the burner block is temporarily switched to a burner block that lowers the combustion amount. Equipped with a control unit that can perform burner switching processing via
The control unit includes:
Executing the burner switching process when the amount of temperature change in the hot water setting temperature immediately before the burner switching condition is satisfied is less than a predetermined temperature value ,
When the temperature change amount becomes higher than the predetermined temperature value, the heat source device immediately switches to a burner block closer to the hot water outlet side of the heat transfer tube. a heat exchanger in which a heat exchanger tube through which a fluid heated by the combustion exhaust gas flows is arranged in a single stage in the direction of flow of the combustion exhaust gas in a body through which the combustion exhaust gas flows;
A burner that generates combustion exhaust gas is arranged to face the heat exchanger tube of the heat exchanger, and the burner is divided into a plurality of burner blocks and arranged in parallel along the direction from the water supply inlet to the hot water outlet of the heat exchanger tube. a combustion section,
burner switching means for switching burner blocks to be burned according to the amount of combustion;
The burner block is switched from the burner block closer to the hot water outlet side of the heat transfer tube to the burner block closer to the water supply inlet side of the heat transfer tube. If the burner switch condition is met, the burner block should be switched once to increase the combustion amount. Equipped with a control unit that can perform burner switching processing via
The control unit includes:
Executing the burner switching process when the amount of temperature change in the hot water setting temperature immediately before the burner switching condition is satisfied is less than a predetermined temperature value ,
When the temperature change amount becomes higher than the predetermined temperature value, the heat source device immediately switches to a burner block closer to the water supply inlet side of the heat transfer tube.

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