JP7285191B2 - Composite heat source machine - Google Patents

Description

The present invention includes a first heat exchanger for supplying hot water, a first burner for heating the first heat exchanger, a second heat exchanger for heating or reheating a bath, and a second heat exchanger for heating the second heat exchanger. The present invention relates to a composite heat source machine including a second burner and a common combustion fan that supplies combustion air to the first burner and the second burner.

Conventionally, in this type of combined heat source machine, each of the first and second burners has a plurality of burner blocks, and a proportional valve is interposed in a common gas supply path for the first and second burners, Combustion capacity of the first burner is increased by changing the combination of burner blocks of the first burner that supplies the fuel gas to the branched gas supply path for the first burner branched from the common gas supply path on the downstream side of the proportional valve. Combination of a burner block of a second burner that is provided with a capacity switching valve that switches between multiple stages and that supplies fuel gas to a branched gas supply path for the second burner branched from a common gas supply path on the downstream side of the proportional valve. is known to provide a capacity switching valve that changes the combustion capacity of the second burner to a plurality of stages.

In such a composite heat source machine, while the first burner is burning at the maximum combustion capacity for supplying fuel gas to all the burner blocks, the second burner has the maximum combustion capacity for supplying fuel gas to all the burner blocks. , the frequency of the combustion oscillation generated in the second burner may match the Helmholtz-type resonance frequency of the combined heat source machine until the combustion of the second burner stabilizes, resulting in resonance noise. . Therefore, conventionally, when an instruction for combustion at the maximum combustion capacity of the second burner is issued during combustion at the maximum combustion capacity of the first burner, fuel gas is first supplied to a part of the burner blocks of the second burner. Combustion of the second burner is started with a small combustion capacity, and when the combustion of the second burner stabilizes after a lapse of a predetermined time, the second burner is burned with the maximum combustion capacity to prevent the generation of resonance noise. is known (see, for example, Patent Document 1).

By the way, in the composite heat source machine, only the first burner has a plurality of burner blocks, and the branch gas supply path for the first burner is changed in combination of the burner blocks for supplying the fuel gas to the first burner. Although a capacity switching valve for switching the combustion capacity of the second burner in a plurality of stages is provided, it is also known that an on-off valve is interposed in the branch gas supply passage for the second burner. In such a composite heat source machine, the first burner that defines the correlation between the total combustion amount of the first burner and the second burner and the rotation speed of the combustion fan during simultaneous combustion in which the first burner and the second burner are combusted together. Based on a simultaneous combustion characteristic line predetermined for each combustion capacity of the burners, control is performed to adjust the rotational speed of the combustion fan according to the total combustion amount of the first burner and the second burner.

In such a composite heat source machine as well, when an instruction to burn the second burner is issued during combustion at the maximum combustion capacity of the first burner, the combustion of the second burner is started and simultaneous combustion corresponding to the maximum combustion capacity is performed. When the rotation speed of the combustion fan is adjusted based on the simultaneous maximum capacity combustion characteristic line, which is the characteristic line, the frequency of the combustion oscillation of the second burner is equal to the Helmholtz resonance of the combined heat source machine until the combustion of the second burner stabilizes. A resonance sound may occur in accordance with the frequency.

However, in this composite heat source machine, the second burner does not have a plurality of burner blocks. Therefore, when an instruction to burn the second burner is issued during combustion at the maximum combustion capacity of the first burner, the combustion of the second burner is started in a state of small combustion capacity as in the above-described combined heat source equipment, and the resonance noise is generated. cannot be prevented from occurring.

Further, when the first burner and the second burner are simultaneously combusted to burn together, if an instruction is given to switch the first burner from a state of burning with a combustion capacity other than the maximum combustion capacity to a state of burning with the maximum combustion capacity, When combustion at the maximum combustion capacity of the first burner is started and the rotational speed of the combustion fan is adjusted based on the simultaneous maximum combustion capacity combustion characteristic line, the burner of the first burner to which fuel gas is supplied upon switching to the maximum combustion capacity Until the combustion of the block stabilizes, the frequency of the combustion oscillation of the burner block may match the Helmholtz resonance frequency of the combined heat source machine, resulting in resonance noise.

JP 2013-170772 A

As a result of diligent efforts, the inventors of the present application have found that when an instruction to burn the second burner is issued during combustion at the maximum combustion capacity of the first burner, the combustion of the second burner is started and the simultaneous maximum capacity is used as a reference. By adjusting the rotation speed of the combustion fan based on a predetermined characteristic line different from the combustion characteristic line, the frequency of the combustion oscillation of the second burner is shifted from the Helmholtz type resonance frequency of the combined heat source machine, thereby suppressing the generation of resonance noise. Also, during simultaneous combustion, even if an instruction is given to switch from a state in which the first burner burns at a combustion capacity other than the maximum combustion capacity to a state in which it burns at the maximum combustion capacity, the maximum combustion capacity of the first burner is used. By adjusting the rotation speed of the combustion fan based on a predetermined characteristic line different from the reference simultaneous maximum capacity combustion characteristic line, the burner to which fuel gas is supplied at the time of switching to the maximum combustion capacity It has been found that the frequency of combustion vibration of the block deviates from the Helmholtz-type resonance frequency of the combined heat source machine to prevent the generation of resonance noise.

Based on the above findings, the present invention provides the resonance noise generated when starting the combustion of the second burner during combustion at the maximum combustion capacity of the first burner, and the first burner at a combustion capacity other than the maximum combustion capacity during simultaneous combustion. An object of the present invention is to provide a composite heat source machine capable of preventing resonance noise generated when switching from a state of burning with combustion capacity to a state of burning with maximum combustion capacity.

The present application provides a first heat exchanger for hot water supply, a first burner having a plurality of burner blocks for heating the first heat exchanger, a second heat exchanger for heating or reheating a bath, and a second heat A second burner for heating the exchanger, a common combustion fan for supplying combustion air to the first and second burners, and a common gas supply path for the first and second burners. Combustion of the first burner by changing the combination of the proportional valve and the branch gas supply path for the first burner branched from the common gas supply path on the downstream side of the proportional valve and supplying the fuel gas. an ability switching valve that switches the ability to a plurality of stages; an on-off valve interposed in a branch gas supply path for the second burner branched from the common gas supply path on the downstream side of the proportional valve; a combustion fan; a proportional valve; A compound heat source machine comprising control means for controlling a capacity switching valve and an on-off valve, wherein the control means controls the first burner and the second burner during simultaneous combustion in which the first burner and the second burner are combusted together. Total combustion of the first burner and the second burner based on a predetermined simultaneous combustion characteristic line corresponding to each combustion capacity of the first burner, which defines the correlation between the total combustion amount and the rotation speed of the combustion fan. It is assumed that control is performed to adjust the rotation speed of the combustion fan according to the amount.

In order to solve the above problems, the first invention of the present application provides a simultaneous maximum capacity combustion characteristic line, which is a simultaneous combustion characteristic line corresponding to the maximum combustion capacity for supplying fuel gas to all the burner blocks of the first burner. , Apart from the reference simultaneous maximum capacity combustion characteristic line, when the combustion of the second burner is started during the combustion at the maximum combustion capacity of the first burner, until the combustion of the second burner stabilizes, the reference A simultaneous maximum capacity combustion characteristic line is set for preventing resonance that occurs when the rotational speed of the combustion fan is adjusted based on the simultaneous maximum capacity combustion characteristic line, and the control means is set to the maximum combustion of the first burner When an instruction to burn the second burner is issued during combustion at full capacity, the on-off valve is opened to start combustion of the second burner, and the combustion fan is operated based on the simultaneous maximum capacity combustion characteristic line for preventing resonance noise. It is characterized in that it is configured to perform transition control to simultaneous combustion that adjusts the rotation speed of.

In addition, in order to solve the above-mentioned problems, the second invention of the present application provides, as a simultaneous maximum capacity characteristic line, a combustion characteristic line other than the maximum combustion capacity of the first burner during simultaneous combustion, in addition to the reference simultaneous maximum capacity combustion characteristic line. Simultaneous maximum combustion capacity that serves as a reference until the combustion of the burner block to which the fuel gas is supplied is stabilized when switching from the state of burning at the maximum combustion capacity to the state of burning at the maximum combustion capacity. A simultaneous maximum capacity combustion characteristic line for preventing resonance noise is set so that the resonance noise that is generated by adjusting the rotation speed of the combustion fan based on the characteristic line does not occur. When an instruction is issued to switch from the state of burning at the combustion capacity of 1 to the state of burning at the maximum combustion capacity, the combustion capacity of the first burner is switched to the maximum combustion capacity and based on the simultaneous maximum capacity combustion characteristic line for preventing resonance noise It is characterized in that it is configured to perform ability switching control for adjusting the rotational speed of the combustion fan.

According to the first invention, when starting combustion of the second burner during combustion at the maximum combustion capacity of the first burner, the rotational speed of the combustion fan is adjusted based on the simultaneous maximum capacity combustion characteristic line for preventing resonance noise. By doing so, the frequency of the combustion oscillation generated by the second burner is shifted from the Helmholtz-type resonance frequency of the combined heat source machine, and the generation of resonance noise can be prevented. Similarly, according to the second invention, when switching from a state in which the first burner burns at a combustion capacity other than the maximum combustion capacity to a state in which the first burner burns at the maximum combustion capacity during simultaneous combustion, a simultaneous maximum combustion capacity combustion characteristic for preventing resonance noise is provided. By adjusting the rotation speed of the combustion fan based on the line, the frequency of the combustion oscillation generated in the burner block to which the fuel gas is supplied at the time of switching to the maximum combustion capacity deviates from the Helmholtz type resonance frequency of the combined heat source machine, It is possible to prevent the occurrence of resonance.

It should be noted that when a predetermined time elapses after the command for combustion of the second burner is issued during the combustion at the maximum combustion capacity of the first burner and the transition control to the simultaneous combustion is performed, the combustion of the second burner stabilizes, Even if the rotation speed of the combustion fan is adjusted based on the reference simultaneous maximum capacity combustion characteristic line, the resonance noise will not occur. Similarly, when an instruction is issued to switch the first burner to a state in which the first burner burns at the maximum combustion capacity during simultaneous combustion, and a predetermined time has passed since the above-mentioned capacity switching control was performed, the fuel gas is supplied by switching to the maximum combustion capacity. Combustion of the burner block is stabilized, and even if the rotational speed of the combustion fan is adjusted based on the reference simultaneous maximum capacity combustion characteristic line, resonance noise will not be generated.

Therefore, in the first invention, the control means adjusts the rotational speed of the combustion fan based on the reference simultaneous maximum capacity combustion characteristic line after a predetermined time has passed since the transition control to the simultaneous combustion was performed. preferably configured to do so. Similarly, in the second invention, the control means performs control for adjusting the rotation speed of the combustion fan based on the simultaneous maximum power combustion characteristic curve serving as a reference when a predetermined time has elapsed since the power switching control was performed. It is desirable to configure According to this, it is possible to return the first burner and the second burner to a normal combustion state while preventing the generation of resonance.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows the structure of the compound heat-source machine of embodiment of this invention. 4 is a graph showing a combustion characteristic line during single combustion of the first burner and a combustion characteristic line during simultaneous combustion of the first burner and the second burner; FIG. 4 is a flow diagram showing details of resonance noise prevention control during combustion of the first burner performed by the control means of the combined heat source machine of the embodiment.

_The combined heat source machine of the embodiment _of the present invention shown in FIG. , a first burner _3-1 below the first heat exchanger 2-1, which heats the first heat exchanger _2-1 , and a burner _3-1 below the second heat exchanger _2-2 , which heats the second heat exchanger _2-2 . and a common combustion _fan 4 for supplying combustion air to the first burner _3-1 and the second burner _3-2 . Inside the can body 1, the _{space inside the can body 1 is divided into a first combustion space 11-1 containing a first heat exchanger 2-1 and a first burner 3-1 , a} second heat exchanger _2-2 , and a second burner 3-1. A partition plate ₁₂ is provided to partition the second combustion space _11-2 in which the combustion chamber 2 is housed. A common exhaust pipe 13 is connected to the upper end of the can body 1 . Then, the combustion gas generated by combustion in the first burner _3-1 flows from the first combustion space _11-1 to the exhaust stack 13 via the first heat exchanger _2-1 , and the combustion gas generated by combustion in the second burner _3-2 flows from the second combustion space _11-2 to the exhaust stack 13 via the second heat exchanger _2-2 .

The first heat exchanger 2 ₁ is connected to an upstream water supply pipe 2 ₁ a and a downstream hot water discharge pipe 2 ₁ b. Then, when a hot water tap (not shown) at the downstream end of the hot water outlet pipe _21b is opened to allow water to flow through the first heat exchanger ₂₁ , the first burner ₃₁ burns and the first heat exchanger 2 ₁ is heated, and hot water at a set temperature is discharged from the tap. A heating circuit is connected to the second heat exchanger _2-2 via a return pipe _2-2a and a supply pipe _2-2b . During the heating operation, the second burner _3-2 is combusted, and hot water is heated by the second heat exchanger _2-2 and circulated in the heating circuit.

The first burner 3 ₁ has three first to third burner blocks 3 ₁ a, 3 ₁ b, and 3 ₁ c. Specifically, a total of 15 unit burners 3a are arranged side by side, two unit burners 3a constitute a first burner block 3 ₁ a, four unit burners 3a constitute a second burner block 3 ₁ b, and the remaining unit burners 3 a constitute a second burner block 3 1 b. Nine unit burners 3a constitute a third burner block 3 ₁ c. Each burner block 3 ₁ a, 3 ₁ b, 3 ₁ c is not composed of a predetermined number of unit burners 3a, and each burner has a combustion capacity similar to that of the predetermined number of unit burners 3a. It is also possible to construct blocks 3 ₁ a, 3 ₁ b, 3 ₁ c. On the other hand, the second burner ₃₂ is composed of a single burner block composed of four unit burners 3a arranged side by side.

A main valve 51 and a proportional valve 52 on the downstream side thereof are interposed in the common gas supply path 5 for the first burner _3-1 and the second burner _3-2 . Further, the gas supply path 5 is branched downstream of the proportional valve 52 into a branch gas supply path _5-1 for the first burner _3-1 and a branch gas supply path _5-2 for the second burner _3-2 . In the branch gas supply path _5-1 for the first burner _3-1 , the combination of the burner blocks _3-1a , _3-1b , and _3-1c for supplying the fuel gas is changed to provide a plurality of combustion capacities of the first burner _3-1 . Three capacity switching _valves 53 ₁ , 53 ₂ , 53 ₃ for switching between stages are provided _. is set.

Specifically _, switching the combustion capacity of _the first burner 3 ₁ will be explained. The combustion capacity of the entire _3-1 is switched to the minimum capacity of the first stage (capacity for two unit burners), the second capacity switching valve _53-2 is opened, and the fuel gas is supplied only to the second burner block _3-1b. By supplying, the combustion capacity of the entire first burner 3 ₁ is switched to the second stage capacity (capacity for four unit burners), and the first and second dual capacity switching valves 53 ₁ and 53 ₂ are opened. By supplying fuel gas to both the first and second burner blocks 3 ₁ a and 3 ₁ b, the combustion capacity of the entire first burner 3 ₁ is increased to that of the third stage (the capacity of six unit burners). ) to open the first and third switching valves 53 ₁ and 53 ₃ to supply fuel gas to both the first and third burner blocks 3 ₁ a and 3 ₁ c. The combustion capacity of the entire 1 burner 3 ₁ is switched to the fourth stage capacity (capacity for 11 unit burners), the first to third capacity switching valves 53 ₁ , 53 ₂ , 53 ₃ are opened to By supplying fuel gas to the third burner blocks 3 ₁ a, 3 ₁ b, 3 ₁ c, the combustion capacity of the entire first burner 3 ₁ is maximized to the fifth stage (capacity of 15 unit burners). I am trying to switch to

The compound heat source machine further comprises a controller 6 comprising a microcomputer as control means for controlling the combustion fan 4, the main valve 51, the proportional valve 52, the capacity switching valves 53 ₁ , 53 ₂ , 53 ₃ and the on-off valve 54. . The controller 6 controls the proportional valve current applied to the proportional valve ₅₂ to be between a predetermined lower limit value and an upper limit value and the rotational speed of the combustion fan 4 at the time of the second burner independent combustion in which only the second burner 32 is combusted. (hereinafter referred to as fan speed) between the lower limit and upper limit speeds corresponding to _the lower limit and upper limit of the proportional valve current, respectively. The amount of combustion required to send out hot water at the temperature) is adjusted according to the control.

Further, the controller 6 sets the proportional valve current between the lower limit value and the upper limit value and the fan rotation speed between the lower limit rotation speed and the upper limit rotation speed during the first burner independent combustion in which only the first burner ₃₁ is burned. Control is performed to vary between the number and the required combustion amount (amount of combustion required to supply hot water at a predetermined hot water supply set temperature), and the required amount of combustion is the current combustion capacity. When the combustion amount of the first burner ₃₁ obtained when the upper limit is set is exceeded, the capacity increase control is performed to increase the combustion capacity, and the proportional valve current is set to the lower limit with the required combustion amount at the current combustion capacity. When the amount of combustion of the first burner 31 becomes equal to or less than the amount of combustion of the first burner ₃₁ obtained when the first burner 31 is set, the ability down control is performed to lower the combustion ability.

KL1 to KL5 in FIG. 2 define the correlation between the combustion amount of the first burner ₃₁ and the fan rotation speed so that the air-fuel ratio becomes _an appropriate value when the first burner burns alone. 1 shows a predetermined combustion characteristic line corresponding to each combustion capability of . KL1 is the combustion characteristic line corresponding to the first stage combustion capacity, KL2 is the combustion characteristic line corresponding to the second stage combustion capacity, KL3 is the combustion characteristic line corresponding to the third stage combustion capacity, and KL4 is the fourth stage combustion characteristic line. and KL5 is a combustion characteristic line corresponding to the fifth stage combustion ability. When the first burner burns alone, the fan speed is adjusted according to the amount of combustion (required amount of combustion) of the first burner ₃₁ based on the combustion characteristic line corresponding to the current combustion capacity.

Further, the controller 6 gives priority to hot _water supply during simultaneous combustion in which both the first burner _3-1 and the second burner _3-2 are combusted. _The proportional valve current is adjusted and the combustion capacity _is switched so that the required amount of combustion is obtained. based on the _simultaneous combustion characteristic lines shown by DL1 to _DL5 in FIG. Control is performed to adjust the fan rotation speed according to the total amount of combustion with the burner ₃₂ . DL1 is the simultaneous combustion characteristic line corresponding to the first stage combustion capacity of the first burner ₃₁ , DL2 is the simultaneous combustion characteristic line corresponding to the second stage combustion capacity of the first burner ₃₁ , and DL3 is the first stage combustion capacity. DL4 is the simultaneous combustion characteristic line corresponding to the combustion capacity of the third stage of the burner ₃₁ , DL5 is the simultaneous combustion characteristic line corresponding to the fourth stage combustion capacity of the first burner ₃₁ , and DL5 is the fifth stage of the first burner ₃₁ . A simultaneous combustion characteristic line (simultaneous maximum capacity combustion characteristic line) corresponding to the combustion capacity of the stage.

By the way, when a combustion instruction for the second burner ₃₂ is issued during combustion at the maximum combustion capacity (fifth-stage combustion capacity) of the first burner ₃₁ , the on-off valve 54 is opened and the second burner When the combustion of _3-2 is started and the fan speed is adjusted based on the simultaneous maximum capacity combustion characteristic line DL5, the frequency of the combustion oscillation of the second burner _3-2 increases until the combustion of the second burner _3-2 stabilizes. Resonant sound may occur at the Helmholtz resonance frequency of the combined heat source machine. Also, at the time of simultaneous combustion in which the first burner ₃₁ and the second burner ₃₂ are combusted together, an instruction to switch the state in which the first burner ₃₁ burns at a combustion capacity other than the maximum combustion capacity to a state in which the first burner 31 burns at the maximum combustion capacity. is issued, the combustion at the maximum combustion capacity of the first burner ₃₁ is started, and when the fan speed is adjusted based on the simultaneous maximum combustion capacity combustion characteristic line DL5, the fuel gas is supplied by switching to the maximum combustion capacity. until the combustion of the burner block of the first burner 3 ₁ (for example, the second burner block 3 ₁ b in switching the combustion capacity from the fourth stage to the fifth stage) stabilizes. frequency coincides with the Helmholtz resonance frequency of the combined heat source machine, resulting in resonance sound.

Therefore, in this embodiment, as the simultaneous maximum combustion capacity combustion characteristic line, the combustion of the second burner ₃₂ is started during the combustion at the maximum combustion capacity of the first burner ₃₁ , separately from the above-mentioned characteristic line DL5 that serves as the reference. Sometimes, until the combustion of the second burner ₃₂ stabilizes, the simultaneous maximum capacity combustion characteristic line DL5' for preventing the resonance noise that occurs when the fan speed is adjusted based on the characteristic line DL5 does not occur. have set. The simultaneous maximum capacity combustion characteristic line LD5' for preventing resonance has a fan rotational speed lower than that of the reference simultaneous maximum capacity combustion characteristic line DL5 by a predetermined number (for example, 30 Hz). Also, when the first burner ₃₁ is switched from a state of burning with a combustion capacity other than the maximum combustion capacity to a state of burning with the maximum combustion capacity during simultaneous combustion, the burner to which the fuel gas is supplied by switching to the maximum combustion capacity. Until the combustion of the block stabilizes, a simultaneous maximum capacity combustion characteristic line is also set in which the resonance noise generated by the fan rotation speed adjustment based on the reference simultaneous maximum capacity combustion characteristic line LD5 does not occur, but this characteristic line is This is the same as the simultaneous maximum capacity combustion characteristic line LD5' for resonance prevention.

FIG. 3 shows the contents of control for preventing resonance noise during combustion of the first burner ₃₁ . In this control, first, in STEP 1, it is determined whether or not a combustion instruction for the second burner ₃₂ has been issued. Then, when the combustion instruction for the second burner _3-2 is issued, the process proceeds to STEP 2 to determine whether or not the first burner _3-1 is burning with the maximum combustion capability. If "YES" is determined in STEP 2, that is, if an instruction for combustion of the second burner _3-2 is issued during combustion at the maximum combustion capacity of the first burner _3-1 , the on-off valve 54 is opened in STEP 3. At the same time, in STEP ₄ , based on the simultaneous maximum capacity combustion characteristic line LD5' for preventing resonance noise, a shift control to simultaneous combustion is performed to adjust the fan rotation speed.

In this way, if the fan speed is adjusted based on the simultaneous maximum capacity combustion characteristic line LD5' for preventing resonance noise, the frequency of the combustion vibration generated by the second burner ₃₂ can be changed from the Helmholtz resonance frequency of the combined heat source machine. It is possible to prevent the occurrence of resonance due to deviation.

Next, in STEP 5, it is determined whether or not a predetermined period of time has elapsed since the control of transition to simultaneous combustion was performed. Until the predetermined time elapses, the process proceeds to STEP7 to determine whether or not an instruction to switch to a combustion capacity other than the maximum combustion capacity of the first burner ₃₁ has been issued _. If the ability remains, return to STEP5 and repeat. Then, when a predetermined time has elapsed since the transition control to simultaneous combustion was performed while the combustion capacity of the first burner ₃₁ remains at the maximum combustion capacity, the process proceeds to STEP 6, and based on the simultaneous maximum capacity combustion characteristic line LD5 as a reference, Performs control to adjust the fan speed.

Combustion of the second burner ₃₂ stabilizes after a predetermined time has passed since the transition control to the simultaneous combustion was performed. Therefore, even if the fan rotation speed is adjusted based on the simultaneous maximum combustion capacity combustion characteristic line LD5 that serves as a reference, resonance noise does not occur. Then, by adjusting the fan speed based on the simultaneous maximum capacity combustion characteristic line LD5, which serves as a reference, the air-fuel ratio becomes an appropriate value, and the combustion state returns to normal.

If an instruction to switch to a combustion capacity other than the maximum combustion capacity of the first burner ₃₁ is issued, proceed from STEP 7 to STEP 8 to switch to the indicated combustion capacity, and proceed to STEP 9 to respond to the indicated combustion capacity. Based on the simultaneous combustion characteristic line DLn (n is any one of 1 to 4), control is performed to adjust the fan speed. Next, proceed to STEP 10 and instruct to switch the first burner ₃₁ to the maximum combustion capacity (instruction to switch the first burner ₃₁ from a state of burning with a combustion capacity other than the maximum combustion capacity to a state of burning with the maximum combustion capacity). is issued. When an instruction to switch to the maximum combustion capacity of the first burner ₃₁ is issued, in STEP11, the combustion capacity of the first burner ₃₁ is switched to the maximum combustion capacity, and at the same time, the process proceeds to STEP12, where the simultaneous maximum capacity for resonance prevention is performed. Based on the combustion characteristic line DL5', ability switching control is performed to adjust the fan speed.

In this way, if the fan speed is adjusted based on the simultaneous maximum capacity combustion characteristic line LD5' for preventing resonance noise, the frequency of the combustion oscillation generated in the burner block to which the fuel gas is supplied when switching to the maximum combustion capacity. deviates from the Helmholtz-type resonance frequency of the composite heat source machine to prevent the occurrence of resonance noise.

Next, return to STEP 5, and when a predetermined time has passed since the performance switching control to the maximum combustion capacity, proceed to STEP 6, and control to adjust the fan rotation speed based on the simultaneous maximum combustion capacity combustion characteristic line DL5 that serves as a reference. I do. After a predetermined period of time has elapsed since the power switching control to the maximum combustion power was performed, the combustion of the burner block to which the fuel gas is supplied is stabilized by the switching to the maximum combustion power. Therefore, even if the fan rotation speed is adjusted based on the simultaneous maximum combustion capacity combustion characteristic line LD5 that serves as a reference, resonance noise does not occur. Then, by adjusting the fan speed based on the simultaneous maximum capacity combustion characteristic line LD5, which serves as a reference, the air-fuel ratio becomes an appropriate value, and the combustion state returns to normal.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto. For example, in the above embodiment, the simultaneous maximum capacity combustion characteristic line for preventing resonance when combustion of the second burner ₃₂ is started during combustion at the maximum combustion capacity of the first burner ₃₁ , and the The simultaneous maximum capacity combustion characteristic line for preventing resonance when switching from a state in which one burner burns at a combustion capacity other than the maximum combustion capacity to a state in which it burns at the maximum combustion capacity is set to the same characteristic line DL5'. However, depending on the model, it may be set to a different characteristic line. In the above-described embodiment, the simultaneous maximum capacity combustion characteristic line LD5' for preventing resonance is set such that the fan rotation speed is lower than the reference simultaneous maximum capacity combustion characteristic line LD5 by a predetermined number. The fan rotation speed may be set higher than the reference simultaneous maximum capacity combustion characteristic line LD5 by a predetermined number. Furthermore, in the above embodiment, the second heat exchanger _2-2 is for heating, but the present invention can be similarly applied to a combined heat source machine in which the second heat exchanger _2-2 is for bath reheating.

DESCRIPTION OF SYMBOLS 2 ₁ ... 1st heat exchanger, 2 ₂ ... 2nd heat exchanger, 3 ₁ ... 1st burner, 3 ₁ a, 3 ₁ b, 3 ₁ c... burner block, 3 ₂ ... 2nd burner, 4... combustion Fan 5 Common gas supply path 5 ₁ Branch gas supply path for first burner 5 ₂ Branch gas supply path for second burner 52 Proportional valve 53 ₁ , 53 ₂ , 53 ₃ . Capacity switching valve 54 Open/close valve 6 Controller (control means) DL5 Reference simultaneous maximum capacity combustion characteristic line DL5' Simultaneous maximum capacity combustion characteristic line for preventing resonance.

Claims (4)

A first heat exchanger for hot water supply, a first burner having a plurality of burner blocks for heating the first heat exchanger, a second heat exchanger for heating or reheating a bath, and a second heat exchanger a second burner for heating, a common combustion fan for supplying combustion air to the first and second burners, and a proportional valve interposed in the common gas supply to the first and second burners. , provided in the branch gas supply path for the first burner branched from the common gas supply path downstream of the proportional valve, and changing the combination of the burner blocks that supply the fuel gas to change the combustion capacity of the first burner A capacity switching valve for switching between stages, an on-off valve interposed in a branch gas supply path for the second burner branched from the common gas supply path downstream of the proportional valve, a combustion fan, a proportional valve, and a capacity switching valve. and a control means for controlling the on-off valve,
The control means regulates the correlation between the total combustion amount of the first burner and the second burner and the rotational speed of the combustion fan during simultaneous combustion in which the first burner and the second burner are combusted together. In one that performs control to adjust the rotation speed of a combustion fan according to the total combustion amount of the first burner and the second burner based on a simultaneous combustion characteristic line predetermined corresponding to each combustion capacity,
As a simultaneous maximum capacity combustion characteristic line corresponding to the maximum combustion capacity for supplying fuel gas to all the burner blocks of the first burner, the first burner When the combustion of the 2nd burner is started during the combustion at the maximum combustion capacity of , until the combustion of the 2nd burner stabilizes, the rotation speed of the combustion fan is adjusted based on the reference simultaneous maximum capacity combustion characteristic line. Simultaneous maximum capacity combustion characteristic line for preventing resonance is set,
When a combustion instruction for the second burner is issued during combustion at the maximum combustion capacity of the first burner, the control means opens the on-off valve to start combustion of the second burner, and at the same time, simultaneously controls the resonance noise prevention. A composite heat source machine characterized by being configured to perform transition control to simultaneous combustion by adjusting the rotational speed of a combustion fan based on a maximum capacity combustion characteristic line. The control means is configured to perform control for adjusting the rotation speed of the combustion fan based on the reference simultaneous maximum capacity combustion characteristic line after a predetermined time has elapsed since the transition control to the simultaneous combustion was performed. The composite heat source machine according to claim 1, characterized in that: A first heat exchanger for hot water supply, a first burner having a plurality of burner blocks for heating the first heat exchanger, a second heat exchanger for heating or reheating a bath, and a second heat exchanger a second burner for heating, a common combustion fan for supplying combustion air to the first and second burners, and a proportional valve interposed in the common gas supply to the first and second burners. , provided in the branch gas supply path for the first burner branched from the common gas supply path downstream of the proportional valve, and changing the combination of the burner blocks that supply the fuel gas to change the combustion capacity of the first burner A capacity switching valve for switching between stages, an on-off valve interposed in a branch gas supply path for the second burner branched from the common gas supply path downstream of the proportional valve, a combustion fan, a proportional valve, and a capacity switching valve. and a control means for controlling the on-off valve,
The control means regulates the correlation between the total combustion amount of the first burner and the second burner and the rotational speed of the combustion fan during simultaneous combustion in which the first burner and the second burner are combusted together. In one that controls the rotation speed of a combustion fan according to the total combustion amount of the first burner and the second burner based on a simultaneous combustion characteristic line predetermined corresponding to each combustion capacity,
As a simultaneous maximum capacity combustion characteristic line corresponding to the maximum combustion capacity for supplying fuel gas to all the burner blocks of the first burner, Until the combustion of the burner block to which the fuel gas is supplied by switching to the maximum combustion capacity stabilizes when the state of burning the first burner at a combustion capacity other than the maximum combustion capacity is switched to the state of burning at the maximum combustion capacity During the period, a simultaneous maximum capacity combustion characteristic line for preventing resonance noise that is generated by adjusting the rotation speed of the combustion fan based on the reference simultaneous maximum capacity combustion characteristic line is set,
During simultaneous combustion, when an instruction is issued to switch the first burner from a state in which the first burner burns at a combustion capacity other than the maximum combustion capacity to a state in which the first burner burns at the maximum combustion capacity, the control means changes the combustion capacity of the first burner to the maximum combustion capacity. and performing capacity switching control for adjusting the rotational speed of the combustion fan based on the simultaneous maximum capacity combustion characteristic line for preventing resonance noise. The control means is configured to perform control for adjusting the rotational speed of the combustion fan based on the reference simultaneous maximum power combustion characteristic line when a predetermined time has elapsed since the power switching control was performed. The composite heat source machine according to claim 3, characterized by:

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