Combustion System

Abstract

To enable exchanging of information among a plurality of centralized control devices each controlling each of a plurality of combustion device groups, by connection structure that can easily be constructed.SOLUTION: A plurality of water heaters 100a1 to 100a2 constituting a first water heater group 150a is centrally controlled by a first system controller 160a via a communication connection by a communication wire group 170a. A plurality of water heaters 100b1 to 100b2 constituting a second water heater group 150b is centrally controlled by a second system controller 160b via a communication connection by a communication wire group 170b. The first system controller 160a and the second system controller 160b mutually exchange information through a cable 190 connecting one water heater 100ax among the first water heater group 150a and one water heater 100by among the second water heater group 150b and through a communication connection via the communication cable groups 170a and 170b.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a combustion system, and more particularly to a combustion system having a plurality of combustion devices connected to a common exhaust duct. [Background technology]

[0002] A system configuration in which multiple combustion devices are connected to a common exhaust duct is known. In such a system configuration, when some of the combustion devices are in combustion operation, it is necessary to prevent exhaust from the combustion devices in operation from flowing back through the common exhaust duct to the combustion devices in operation that are not in operation.

[0003] For example, Japanese Patent No. 6767087 (Patent Document 1) describes a control method for preventing backflow of exhaust gas by operating a blower fan in a combustion device where combustion is stopped during combustion operation of any of multiple combustion devices connected to a common collective exhaust duct.

[0004] Furthermore, Patent Gazette No. 3608492 (Patent Document 2) describes a configuration in which a hot water supply system in which multiple water heaters are connected and operated, a system controller is placed for each of a predetermined number of water heaters, and further, a higher-level system controller is placed to oversee the multiple system controllers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6767087 [Patent Document 2] Patent No. 3608492 Summary of the Invention [Problem to be solved by the invention]

[0006] Here, a system is assumed in which a plurality of combustion device groups, each of which is made up of a plurality of combustion devices, are arranged and each of the plurality of combustion device groups is controlled by a different system controller. In such a system, if the plurality of combustion device groups are connected to a common collective exhaust duct, in order to apply the control described in Patent Document 1 for the purpose of preventing exhaust backflow, a centralized control is required in which information related to the combustion devices in combustion operation is shared among the plurality of combustion device groups.

[0007] Alternatively, in addition to the above-mentioned control for preventing backflow of exhaust gas, it is expected that a configuration for transmitting and receiving information between a plurality of combustion device groups controlled by different system controllers will be required.

[0008] However, when the system configuration of Patent Document 2 is applied to exchange information between a plurality of combustion device groups, it becomes necessary to place an additional top-level system controller, which raises concerns about rising costs. Furthermore, depending on the layout, the length of the wiring for communication connections between the top-level system controller and the plurality of system controllers may become long, which raises concerns about an increase in the construction load.

[0009] Furthermore, even if a configuration is adopted in which communication is established between system controllers disposed in each of a number of combustion device groups, rather than placing a top-level system controller as in Patent Document 2, there is a concern that the construction load for establishing communication connections between the system controllers may increase depending on the layout.

[0010] In particular, there is concern that the problems caused by the above-mentioned arrangement layout will become more pronounced in cases where new system controllers and combustion device groups are additionally arranged in addition to existing system controllers and combustion device groups.

[0011] The present invention has been made to solve these problems, and an object of the present invention is to enable the exchange of information between multiple centralized control devices, each of which controls a group of multiple combustion devices, by means of a connection configuration that is easy to install. [Means for solving the problem]

[0012] One aspect of the present invention provides a combustion system. The combustion system includes a plurality of combustion device groups and a plurality of centralized control devices arranged corresponding to the plurality of combustion device groups, respectively. Each of the plurality of combustion device groups includes a plurality of combustion devices. Each combustion device has a first connection terminal for communication connection with the centralized control device and a second connection terminal for communication connection with another combustion device. The plurality of combustion device groups include a first combustion device group controlled by a first centralized control device of the plurality of centralized control devices, and a second combustion device group controlled by a second centralized control device of the plurality of centralized control devices. The first and second centralized control devices are configured to be able to communicate with each other by communication connection between the second connection terminals of a first combustion device of the plurality of combustion devices constituting the first combustion device group and a second combustion device of the plurality of combustion devices constituting the second combustion device group. Effect of the Invention

[0013] According to the present invention, information can be exchanged between the first and second centralized control devices through a communication connection between the first and second combustion devices, which can be arbitrarily selected in the first and second combustion device groups, thereby facilitating the construction of communication among multiple centralized control devices. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of a water heater, which is an example of a combustion device constituting a combustion system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a conceptual diagram showing an example of a connection destination of an exhaust port of the water heater shown in FIG. [Diagram 3] 1 is a block diagram illustrating a configuration of a hot water supply system, which is an example of a combustion system according to an embodiment of the present invention. [Figure 4] 4 is a block diagram illustrating a communication configuration between water heaters in the hot water supply system shown in FIG. 3. [Diagram 5]FIG. 4 is a conceptual diagram illustrating a connection configuration of an exhaust system of each water heater in the hot water supply system shown in FIG. [Figure 6] 4 is a flowchart illustrating an example of centralized control for exhaust backflow prevention operation in each water heater group of the hot water supply system shown in FIG. 3. [Figure 7] FIG. 4 is a first conceptual diagram illustrating an example of the operation of the hot water supply system shown in FIG. [Figure 8] FIG. 4 is a second conceptual diagram illustrating an example of the operation of the hot water supply system shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are designated by the same reference characters, and their description will not be repeated in principle.

[0016] FIG. 1 is a schematic diagram of a water heater, which is an example of a combustion device constituting a combustion system according to the present embodiment.

[0017] With reference to Fig. 1, a water heater 100 includes a burner 10 that burns a fuel such as gas, a blower fan 11, a heat exchanger 12, an exhaust path 20, an exhaust port 25, a rotation speed sensor 41 and a current sensor 42 for the blower fan 11, a controller 50, and connection terminals 101, 102. In the water heater 100 illustrated in Fig. 1, the above-mentioned elements constitute a combustion device to which the present invention is applied. The burner 10 is shown as one embodiment of a "combustion mechanism." The fuel burned by the burner 10 is not particularly limited.

[0018] Blower fan 11 is driven to rotate by a fan motor (not shown) to supply combustion air to burner 10. The amount of air blown from blower fan 11 is determined according to the fan rotation speed. Heat exchanger 12 recovers heat from the combustion gas generated by burner 10 and heats the hot water flowing through heat exchanger 12. This allows water heater 100 to operate as a continuous heating type water heater by heating water introduced from a water inlet and discharging it.

[0019] The combustion gas after heat recovery is guided to exhaust port 25 by exhaust path 20 and discharged to the outside of water heater 100. In this manner, in the combustion device, during combustion operation by burner 10, an intake and exhaust path from blower fan 11 to exhaust port 25 is formed by the operation of blower fan 11.

[0020] The controller 50 controls the operation of the components of the water heater 100. The controller 50 is typically configured by a microcomputer in which a predetermined program is stored in advance. Furthermore, the controller 50 controls the start / stop of the combustion operation of the burner 10 and the amount of fuel gas supplied to the burner 10, as well as the start / stop of the blower fan 11 and the fan rotation speed when in operation.

[0021] A rotation speed sensor 41 is provided in the blower fan 11, and a current sensor 42 is provided in a fan motor (not shown) that rotates and drives the blower fan 11. The outputs of the rotation speed sensor 41 and the current sensor 42 are input to a controller 50.

[0022] The amount of air required for combustion in the burner 10 is proportional to the amount of fuel supplied to the burner 10. Therefore, the rotation speed of the blower fan 11 (hereinafter also referred to as "fan rotation speed Nf") is controlled to a target rotation speed set according to the required amount of air. For example, the controller 50 executes the rotation speed control of the blower fan 11 by adjusting the drive voltage of the fan motor so as to bring the detected value of the fan rotation speed Nf by the rotation speed sensor 41 closer to the target rotation speed. At this time, the drive current If of the fan motor of the blower fan 11 is detected by the current sensor 42.

[0023] The connection terminal 101 is provided for connecting a communication line (e.g., a two-core communication line) for communication with a system controller described later. When the communication line is connected to the connection terminal 101, the controller 50 becomes capable of communicating with the system controller to send and receive information. One or more connection terminals 101 may be provided.

[0024] The connection terminal 102 is provided for connecting a communication line (e.g., a communication cable) for communication with the controller 50 of another water heater 100. One or more connection terminals 102 may be provided. When the communication line is connected to the connection terminal 102, the controller 50 becomes capable of communicating with another water heater 100 to send and receive information. Communication between water heaters can be performed, for example, according to the contents described in JP 2003-222399 A.

[0025] Connection terminal 101 corresponds to one embodiment of a “first connection terminal,” and connection terminal 102 corresponds to one embodiment of a “second connection terminal.” In this manner, water heater 100 has both a communication function with the system controller and a communication function with other water heaters 100.

[0026] FIG. 2 shows an example of the connection destination of the exhaust port 25.

[0027] 2, a plurality of water heaters 100 are connected to a common exhaust pipe 200. Common exhaust pipe 200 is connected to exhaust port 25 of each of water heaters 100.

[0028] In a configuration in which the exhaust sides are commonly connected as in Figure 2, there is a concern that exhaust gas output from some of the water heaters 100 during combustion operation to the shared exhaust pipe 200 may flow back from the exhaust port 25 to other water heaters 100 whose combustion is stopped.

[0029] Therefore, as described in Patent Document 1, by transmitting and receiving information between water heaters 100, during the combustion operation of any of the water heaters 100, the "exhaust backflow prevention operation" is performed in which the blower fan 11 is operated in the water heater 100 whose combustion is stopped, thereby suppressing the above-mentioned exhaust backflow. The fan rotation speed Nf of the blower fan 11 during the exhaust backflow prevention operation can be set to a predetermined fixed value. Alternatively, when the number of water heaters 100 in combustion operation among the multiple water heaters 100 connected to the shared exhaust pipe 200 can be obtained, it is also possible to set the fan rotation speed Nf higher as the number of the water heaters 100 increases.

[0030] FIG. 3 is a block diagram illustrating the configuration of a hot water supply system shown as an example of a combustion system according to this embodiment.

[0031] Referring to FIG. 3, hot water system 250 includes a plurality of water heater groups 150a and 150b, and a plurality of system controllers 160a and 160b arranged corresponding to water heater groups 150a and 150b, respectively.

[0032] Water heater group 150a includes m (m: integer of 2 or greater) water heaters 100a1-100am. Similarly, water heater group 150b includes n (n: integer of 2 or greater) water heaters 100b1-100bn. Each of water heaters 100a1-100am, 100b1-100bn has the configuration of water heater 100 shown in FIG.

[0033] In this way, the numbers (m, n) of water heaters 100 included in water heater groups 150a and 150b, i.e., the numbers of water heaters 100 centrally controlled by system controllers 160a and 160b, are arbitrary. In the following, when the water heaters are generally described, they will be referred to as water heater 100, but when it is necessary to distinguish between water heaters, they will be referred to with a subscript, such as water heater 100a1.

[0034] System controller 160a is connected to each connection terminal 101 (FIG. 1) of water heaters 100a1-100am via communication line group 170a, and transmits and receives information between water heaters 100a1-100am. This allows system controller 160a to centrally control water heaters 100a1-100am. For example, system controller 160a can control operation (hot water supply operation involving combustion) and stop of each of water heaters 100a1-100am according to the hot water supply load of water heater group 150a as a whole.

[0035] Similarly, system controller 160b is connected to each connection terminal 101 (FIG. 1) of water heaters 100b1-100bn via communication line group 170b, and transmits and receives information between water heaters 100b1-100bn. This allows system controller 160b to centrally control water heaters 100b1-100bn. For example, system controller 160b can control operation (hot water supply operation involving combustion) and stop of each of water heaters 100b1-100bn according to the hot water supply load of water heater group 150b as a whole.

[0036] Incidentally, system controllers 160a, 160b can also be disposed inside any of water heaters 100a1-100am or any of water heaters 100b1-100bn.

[0037] 3, system controllers 160a and 160b correspond to one embodiment of "multiple centralized control devices", and in particular, system controller 160a corresponds to the "first centralized control device", and system controller 160b corresponds to the "second centralized control device". Furthermore, water heater groups 150a and 150b correspond to one embodiment of "multiple combustion device groups", and in particular, water heater group 150a composed of water heaters 100a1-100am corresponds to the "first combustion device group", and water heater group 150b composed of water heaters 100b1-100bn corresponds to the "second combustion device group".

[0038] In hot water supply system 250 of this embodiment, connection terminals 102 (FIG. 1) of one water heater 100ax (x: an integer from 1 to m; in the example of FIG. 3, x=m) among water heaters 100a1-100am in water heater group 150a and one water heater 100by (y: an integer from 1 to n; in the example of FIG. 3, y=1) among water heaters 100b1-100bn in water heater group 150b are connected to each other by cable 190. That is, water heater 100ax corresponds to an example of a "first combustion device," and water heater 100by corresponds to an example of a "second combustion device."

[0039] FIG. 4 shows a block diagram illustrating a communication configuration between water heaters in hot water supply system 250.

[0040] 4, the connection terminals 102 of the water heater 100ax of the water heater group 150a and the water heater 100by of the water heater group 150b are communicatively connected by a cable 190. This allows information to be exchanged between the water heater 100ax and the water heater 100by via the cable 190, for example, by communication using a pulse signal or serial communication.

[0041] In the water heating group 150a, the water heating device 100ax is also connected to the system controller 160a by the connection terminal 101, and therefore can notify the system controller 160a of information related to the water heating group 150b received from the water heating device 100by. This allows the system controller 160a to perform centralized control of the water heating devices 100a1-100am, reflecting the information of the water heating group 150b. Conversely, the system controller 160a can use the water heating device 100ax to transmit information related to the water heating group 150a to the water heating group 150b.

[0042] Similarly, in water heating group 150b, water heating device 100by is also connected to system controller 160b via connection terminal 101, and can therefore notify system controller 160b of information relating to water heating group 150a received from water heating device 100ax. This allows system controller 160b to perform centralized control of water heating devices 100b1-100bn, reflecting the information of water heating group 150a. Furthermore, system controller 160b can transmit information relating to water heating device group 150b to water heating device group 150a using water heating device 100by (100b1).

[0043] As a result, as shown in Fig. 3, according to the hot water supply system 250, it is possible to transmit and receive information between the system controllers 160a and 160b of the hot water supply groups 150a and 150b without disposing the upper system controller 165 and the communication line 161 connecting the system controllers 160a and 160b. Since the selection of the hot water supply 100ax from the hot water supply 100a1-100am and the selection of the hot water supply 100by from the hot water supply 100b1-100bn are arbitrary, it is possible to select a combination of the hot water supply 100 each of which is easy to install the cable connection between the hot water supply groups 150a and 150b, and to lay the cable 190. For example, by connecting the cable 190 between the connection terminals 102 of the hot water supply 100 each of which is arranged closest to each other, it is possible to facilitate the installation for the communication connection between the system controllers 160a and 160b of the hot water supply groups 150a and 150b.

[0044] Next, an example of centralized control using information exchanged between water heater groups 150a and 150b will be described.

[0045] 5, common exhaust pipe 200a to which exhaust ports 25 (FIG. 1) of water heaters 100a1-100am are connected and common exhaust pipe 200b to which exhaust ports 25 (FIG. 1) of water heaters 100b1-100bn are connected are connected to exhaust duct 200x. As a result, water heater groups 150a and 150b are configured such that exhaust ports 25 of each water heater 100 are connected to a common exhaust path.

[0046] As a result, in hot water supply system 250, exhaust backflow prevention operation in water heater 100 during combustion stop must be performed by all of water heater groups 150a and 150b, as described in Patent Document 1. For example, even if all of water heaters 100a1-100am in water heater group 150a are during combustion stop, if any of water heaters 100b1-100bn in water heater group 150b performs combustion operation, exhaust backflow may occur.

[0047] In addition, during the combustion operation of each water heater, in addition to the state in which the burner 10 (combustion mechanism) is actually performing combustion operation, the operation may also include a state in which exhaust operation is performed after the combustion operation has ended, and a state in which post-purge operation is performed after the combustion operation has ended in preparation for another combustion operation.

[0048] For this reason, in hot water supply system 250, information indicating the presence or absence of water heater 100 in combustion operation within the water heater group is transmitted and received by the cable communication shown in Fig. 4. Specifically, water heater 100ax transmits information indicating whether water heater group 150a is "combustion stopped" or "combustion in operation" to water heater 100by. When water heater group 150a is combustion stopped, it means that all water heaters 100a1-100am have stopped combustion, and when water heater group 150a is in combustion operation, it means that at least one of water heaters 100a1-100am is in combustion operation.

[0049] Conversely, water heater 100by transmits information to water heater 100ax indicating whether water heater group 150b is in "combustion stopped" or "combustion operation." As above, when water heater group 150b is in combustion stopped, it means that all water heaters 100b1-100bn have stopped combustion, and when water heater group 150b is in combustion operation, it means that at least one of water heaters 100b1-100bn is in combustion operation. In this way, "combustion stopped" and "combustion operation" of water heater groups 150a, 150b correspond to "first state" and "second state," respectively.

[0050] Fig. 6 shows a flow chart of exhaust backflow prevention operation as an example of centralized control in each water heater group of the combustion system of this embodiment. The control process shown in the flow chart of Fig. 6 is executed by each of system controllers 160a and 160b. Hereinafter, system controllers 160a and 160b are collectively referred to as system controller 160.

[0051] 6, system controller 160 checks whether or not there is a water heater 100 in combustion operation in the self-operated water heater group in step (hereinafter also simply referred to as "S") 110. The self-operated water heater group refers to water heater group 150a in the control processing by system controller 160a, and refers to water heater group 150b in the control processing by system controller 160b.

[0052] When there is a water heater 100 in the own water heater group that is in combustion operation (YES determination in S110), system controller 160 notifies the other water heater groups that the own water heater group is in combustion operation in S120. Note that the other water heater groups refer to water heater group 150b in the control processing by system controller 160a, and refer to water heater group 150a in the control processing by system controller 160b.

[0053] In S120, the water heater 100ax or 100by is instructed to transmit information to the connection destination of the cable 190 that the private water heater group is in combustion operation.

[0054] Furthermore, system controller 160 instructs water heaters 100 in the private water heater group whose combustion is stopped to operate blower fans 11 at S130. This operates the blower fans in all water heaters 100 in the private water heater group, making it possible to prevent exhaust air from flowing into exhaust port 25 of water heater 100 from shared exhaust pipe 200a or 200b.

[0055] If there is no water heater 100 in the self-heating water heater group that is in combustion operation (NO judgment at S110), the system controller 160 notifies the other water heater groups by S140 that the self-heating water heater group has stopped combustion, i.e., that all water heaters 100 have stopped combustion.

[0056] Furthermore, in S150, system controller 160 determines whether the other water heater group is in combustion operation based on information from the other water heater group via cable 190. As described above, when the other water heater group is in combustion operation, the information is notified by the processing of S120 by system controller 160 of the other water heater group.

[0057] If the other water heater group is in combustion operation (YES in S150), system controller 160 advances the process to S130 and instructs water heater 100 in the own water heater group for which combustion is stopped to operate blower fan 11. This operates blower fans 11 of all water heaters 100 in the own water heater group, thereby preventing exhaust air from water heater 100 in the other water heater group that is in combustion operation via exhaust duct 200x from flowing back into water heater 100 in the own water heater group for which combustion is stopped.

[0058] In response to this, if combustion is stopped in the other water heater groups in addition to the own water heater group (NO in S150), system controller 160 instructs all water heaters 100 in the own water heater group to stop blower fans 11 in S160. This prevents unnecessary operation of blower fan 11 when exhaust air is not being output to exhaust duct 200x, reducing power consumption and preventing noise caused by fan operation.

[0059] Furthermore, system controller 160 may be configured to transmit information to all water heaters in the self-operated water heater group as to whether the self-operated water heater group is in combustion stopped state (first state) or combustion stopped state (second state) in S120 and S140. When configured in this manner, system controller 160 can transmit information to the other water heater groups, regardless of which of the multiple water heaters constituting the self-operated water heater group is communicatively connected to a water heater in another water heater group.

[0060] Figures 7 and 8 show an example of operation when hot water supply system 250 is centrally controlled by the control process shown in Figure 6. In particular, Figures 7 and 8 show an example of operation when information on whether the self-contained water heater group is in a first state (all water heaters 100 are in combustion stopped) or a second state (at least one water heater 100 is in combustion operation) is notified using the presence or absence of transmission of a pulse signal.

[0061] 7 and 8, in order to simplify the notation, an example is shown in which water heater groups 150a and 150b are respectively configured by two water heaters 100a1, 100a2 and two water heaters 100b1, 100b2, and a communication path (cable 190) for the above-mentioned pulse signal is formed between water heater 100a2 and water heater 100b1. Specifically, when the own water heater group is in a combustion stopped state (first state), a pulse signal is transmitted to the other water heater groups, while when the own water heater group is in a combustion operation state (second state), output of the pulse signal to the other water heater groups is stopped.

[0062] In addition, in Figs. 7 and 8, in each water heater 100, when blower fan 11 is operating, it is indicated by a circled "f", and when combustion is in progress, it is indicated by a circled "B".

[0063] FIG. 7 shows the operation when combustion operation is started in one of the water heater groups from a state in which all water heaters 100 in all water heater groups are in a combustion stopped state.

[0064] In Fig. 7(a), both water heater groups 150a and 150b are in the combustion stopped state. Therefore, by each of system controllers 160a, 160b executing the process of S140 in Fig. 6, a pulse signal is transmitted from water heater 100a2 of water heater group 150a to water heater 100b1 of water heater group 150b, and a pulse signal is also transmitted from water heater 100b1 of water heater group 150b to water heater 100a2 of water heater group 150a.

[0065] In this state, as a result of a NO determination being made in S150 of FIG. 6, each of system controllers 160a, 160b stops blower fans 11 in all of water heaters 100a1, 100a2 and water heaters 100b1, 100b2.

[0066] In Fig. 7(b), water heater 100a1 in water heater group 150a starts combustion operation. In water heater 100a1, blower fan 11 also operates to supply combustion air. In conjunction with the combustion operation of water heater 100a1, system controller 160a operates blower fan 11 of water heater 100a2, whose combustion is stopped, in S130 (Fig. 6). Furthermore, by the processing of S120 (Fig. 6) by system controller 160a, water heater 100a2 stops outputting a pulse signal to water heater 100b1 in water heater group 150b.

[0067] 7(c), water heater 100b1 detects the stop of the output of the pulse signal from water heater group 150a (water heater 100a2) and notifies system controller 160b of the detection. As a result, system controller 160b detects that water heater group 150a has transitioned from combustion stopped (first state) to combustion operating (second state).

[0068] In Fig. 7(d), system controller 160b operates blower fans 11 of all water heaters 100b1, 100b2 in water heater group 150b by the process of S130 (Fig. 6). This prevents exhaust air from water heater group 150a (water heater 100a1) discharged to exhaust duct 200x from flowing back into water heaters 100b1, 100b2 of water heater group 150b.

[0069] Next, FIG. 8 shows the operation of water heater 100a1, which has started the combustion operation in FIG. 7(b), when the combustion is stopped.

[0070] Fig. 8(a) shows the same state as Fig. 7(d), where water heater 100a1 of water heater group 150a is in combustion operation, and blower fan 11 is operated to suppress backflow of exhaust gas in other water heaters 100a2 (water heater group 150a) and 100b1, 100b2 (water heater group 150b) whose combustion is stopped. Furthermore, output of a pulse signal from water heater 100a2 of water heater group 150a to water heater 100b1 of water heater group 150b is stopped, while a pulse signal is transmitted from water heater 100b1 to water heater 100a2.

[0071] In Fig. 8(b), water heater 100a1 in water heater group 150a stops its combustion operation. As a result, blower fan 11 in water heater 100a1 is also stopped. As combustion in water heater 100a1 stops while a pulse signal is being received from water heater group 150b, system controller 160a stops blower fan 11 in water heater 100a2 by processing S160 (Fig. 6). Furthermore, by processing S140 (Fig. 6) by system controller 160a, water heater 100a2 resumes transmitting a pulse signal to water heater 100b1 in water heater group 150b.

[0072] 8(c), water heater 100b1 detects the transmission of a pulse signal from water heater group 150a (water heater 100a2) and notifies system controller 160b of the detection. As a result, system controller 160b detects that water heater group 150a has transitioned from combustion operation (second state) to combustion stopped (first state).

[0073] In Fig. 8(d), system controller 160b stops blower fans 11 of all water heaters 100b1, 100b2 in water heater group 150b by the process of S160 (Fig. 6). As a result, when both water heater groups 150a, 150b are in a combustion stopped state, the blower fans of all water heaters 100a1, 100a2, 100b1, 100b2 are stopped.

[0074] As described above, in the water heating system 250, in a configuration in which the exhaust port 25 of each water heater 100 is connected to a common exhaust duct 200x between water heater groups 150a, 150b in which separate system controllers 160a, 160b are arranged, centralized control for exhaust backflow prevention operation in the entire water heater groups 150a, 150b can be realized using the communication connection of this embodiment.

[0075] In particular, by transmitting and receiving information on whether each water heater group is in combustion stopped state (first state) or in combustion operation state (second state) depending on the presence or absence of a pulse signal, the centralized control for the exhaust backflow prevention operation described above can be easily realized. In this case, as illustrated in Figures 7 and 8, by transmitting a pulse signal while combustion is stopped and stopping the output of the pulse signal while combustion is in operation, blower fan 11 can be operated when the pulse signal cannot be transmitted normally due to a broken wire, etc.

[0076] Conversely, if a pulse signal were sent during combustion operation, there would be a concern that if the pulse signal could not be sent normally, it would be impossible to operate the blower fan 11 when exhaust backflow prevention operation is required. In other words, it is understood that the operation illustrated in Figures 7 and 8 can be used to deal with abnormalities in the transmission of the pulse signal and to design the control of the blower fan 11 for exhaust backflow prevention operation on the safe side.

[0077] Furthermore, it is also possible to transmit multi-bit data by serial communication, rather than a pulse signal, for information related to the combustion operation of the water heater group. In this case, in addition to distinguishing between when combustion is stopped (first state) and when combustion is in operation (second state), it is possible to transmit information related to, for example, the number of water heaters 100 in combustion operation. As an example, it becomes possible to control the variably setting of the rotation speed of blower fan 11 of each water heater 100 in the water heater group in which combustion is stopped, depending on the number of water heaters 100 in combustion operation.

[0078] In addition, in this embodiment, an example has been described in which the hot water supply system 250 (i.e., the combustion system) is configured with two hot water supply groups (combustion device groups) each controlled by two system controllers, but in a combustion system with three or more hot water supply groups (combustion device groups), i.e., three or more system controllers, the same effect can be obtained by forming a group of two of the combustion device groups into a single group. That is, even in a combustion system having three or more combustion device groups, it is possible to exchange information between the multiple system controllers corresponding to the multiple combustion device groups without requiring direct communication between the multiple system controllers. In this case, since it is expected that a large amount of information will be exchanged, it is preferable to use serial communication for communication between hot water supply groups of different combustion device groups.

[0079] For example, when the communication connection according to this embodiment is applied to a combustion system having three combustion device groups, the combustion device for communication connection with the second combustion device group and the combustion device for communication connection with the third combustion device group can be different combustion devices in the first combustion device group. In this configuration, each combustion device in the first combustion device group does not need to have multiple second connection terminals 102, and each needs to have one.

[0080] The centralized control by the system controller, which involves the exchange of information between the multiple combustion device groups described in this embodiment, is not limited to the exhaust backflow suppression operation described above, but can be applied to any control. For example, when incomplete combustion is detected by a CO sensor (not shown), the detection is notified to all the combustion device groups connected to a common exhaust passage, so that each system controller can realize centralized control such as stopping the combustion operation in all the water heaters 100 and operating the blower fan 11.

[0081] In addition, in this embodiment, a continuous heating water heater is shown as a representative example of a combustion device, but the communication configuration of this embodiment can be applied to a combustion system composed of any combustion device that burns fuel, even if it is not a water heater.

[0082] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0083] 10 burner, 11 blower fan, 12 heat exchanger, 20 exhaust path, 25 exhaust port, 41 rotation speed sensor, 42 current sensor, 50, 160a controller, 100, 100a1 to 100am, 100ax, 100b1 to 100bn, 100by water heater, 101, 102 connection terminal, 150a, 150b water heater group, 160a, 160b system controller, 170a, 170b communication line group, 190 cable, 200, 200a, 200b shared exhaust pipe, 200x exhaust duct, 250 water heating system.

Claims

1. A plurality of combustion devices; a plurality of centralized control devices arranged corresponding to the plurality of combustion device groups, Each of the plurality of combustion device groups includes a plurality of combustion devices, Each of the combustion devices is a first connection terminal for communication connection with the central control device; a second connection terminal for communication connection with another of the combustion devices; The plurality of combustion device groups include: a first combustion device group controlled by a first centralized control device among the plurality of centralized control devices; a second group of combustion devices controlled by a second centralized control device among the plurality of centralized control devices; the first and second centralized control devices are configured to be able to communicate with each other by communication-connecting the second connection terminals of a first combustion device among the plurality of combustion devices constituting the first combustion device group and a second combustion device among the plurality of combustion devices constituting the second combustion device group.

2. Each of the combustion devices is A combustion mechanism that burns fuel; a blower fan for supplying combustion air to the combustion mechanism; an exhaust port for discharging combustion gas from the combustion mechanism; the exhaust ports of the plurality of combustion devices constituting the first combustion device group and the exhaust ports of the plurality of combustion devices constituting the second combustion device group are connected to a common exhaust path; the first centralized control device is configured to operate the blower fans in all of the plurality of combustion devices in the first combustion device group when it detects, based on information transmitted from the second combustion device to the first combustion device, that the combustion mechanism is operating in at least one of the plurality of combustion devices in the second combustion device group; 2. The combustion system according to claim 1, wherein the second centralized control device is configured to operate the blower fans in all of the plurality of combustion devices in the second combustion device group when the second centralized control device detects, based on information transmitted from the first combustion device to the second combustion device, that the combustion mechanism is operating in at least one of the plurality of combustion devices in the first combustion device group.

3. the first centralized control device is configured to stop the blower fans in all of the plurality of combustion devices in the first group of combustion devices when it detects, based on information transmitted from the second combustion device to the first combustion device, that the combustion mechanisms in all of the plurality of combustion devices in the second group of combustion devices are stopped in a case where the combustion mechanisms are stopped in all of the plurality of combustion devices in the first group of combustion devices; 3. The combustion system according to claim 2, wherein when the combustion mechanisms are stopped in all of the plurality of combustion devices in the second group of combustion devices, based on information transmitted from the first combustion device to the second combustion device, the second centralized control device is configured to stop the blower fans in all of the plurality of combustion devices in the second group of combustion devices when it detects that the combustion mechanisms are stopped in all of the plurality of combustion devices in the first group of combustion devices based on information transmitted from the first combustion device to the second combustion device.

4. the first combustion device is configured to transmit, to the second combustion device, information indicating whether the first combustion device group is in a first state in which the combustion mechanisms of all of the plurality of combustion devices are stopped, or a second state in which the combustion mechanism of at least one of the plurality of combustion devices is operating, depending on whether a pulse signal is transmitted to the second combustion device; 4. The combustion system according to claim 3, wherein the second combustion device is configured to transmit information indicating whether the second combustion device group is in the first state or the second state to the first combustion device based on whether a pulse signal is transmitted to the first combustion device.

5. the first combustion device is configured to output the pulse signal to the second combustion device when the first combustion device group is in the first state, and to stop outputting the pulse signal to the second combustion device when the first combustion device group is in the second state; 5. The combustion system of claim 4, wherein the second combustion device is configured to output the pulse signal to the first combustion device when the second combustion device group is in the first state, and to stop outputting the pulse signal to the first combustion device when the second combustion device group is in the second state.

6. The combustion system according to any one of claims 1 to 5, wherein the combustion device is a combustion heating water heater.

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