JP3584558B2 - 1-can 2-circuit water heater - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention can perform heat exchange heating by using a single burner for two circuits, a bath reheating circuit for reheating water from a bathtub and a hot water supply circuit for heating and supplying hot water from a water supply system. The present invention relates to a one-can two-circuit hot water supply device having a heat exchange can body.
[0002]
[Prior art]
Conventionally, in a one-can, two-circuit hot water supply apparatus, for example, in the case where a bath reheating operation and a hot water supply operation are simultaneously performed, the burner combustion control is performed by feedforward control and feedback control, and the set temperature of the tapping temperature on the hot water supply side. The adjustment to is achieved by adjusting the combustion amount by the feedback control. When the sum of the feedforward control value and the feedback control value is a large value equal to or more than a certain value, the safety of the can body is prevented by preventing an overload on the can body such as an overheated state of the can body. For the purpose of achieving this, the burner combustion is once turned off, and when the sum is reduced to a small value, the combustion is turned on again. At this time, when the burner combustion is once turned off, the rotation speed of the blower fan is calculated from the rotation speed during combustion, and the rotation speed in the post-purge operation performed after the burner is turned off due to operation stop, that is, the post-purge rotation speed. Had been changed to
In the conventional one-can, two-circuit water heater provided with a bath reheating circuit and a hot water supply circuit, when the bath reheating alone operation is performed, the heat exchange unit of the hot water supply circuit in which water supply is stopped is overheated. In order to prevent the state from becoming a state, when the temperature sensor of the heat exchange section on the hot water supply circuit detects a high temperature above a certain temperature, the burner combustion is turned off during that time, and when the temperature drops below the certain temperature, the burner is turned on again. Was like that. At that time, if the burner combustion is turned off once, the temperature sensor of the heat exchange section on the hot water supply circuit side detects the temperature equal to or higher than a certain temperature, and if the burner combustion is turned off, the rotation speed of the blower fan is reduced. The number of revolutions during combustion was changed to the number of revolutions in the post-purge operation performed after the burner was turned off due to the stoppage of operation, that is, the number of revolutions of the post-purge.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional apparatus, the post-purge rotation speed of the blower fan is normally set to the maximum rotation speed in order to sweep out exhaust gas in the burner, so each time the burner is temporarily turned off during the operation, When the rotation speed of the blower fan is changed to the post-purge rotation speed, the rotation speed is large, and there is a problem that the fan rotation noise becomes noise.
[0004]
Therefore, the present invention solves the above-mentioned drawbacks of the conventional apparatus, prevents the noise of the blower fan generated when the burner is temporarily turned off during operation, and generates the noise when the burner is temporarily turned off. It is an object of the present invention to provide a one-can, two-circuit hot water supply apparatus capable of preventing a rapid decrease in heating heat quantity and smoothly performing ignition when a burner is turned on again.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a one-can two-circuit hot water supply apparatus of the present invention comprises two circuits, a bath reheating circuit for reheating water from a bathtub and a hot water supply circuit for heating and supplying water from a water supply. And a heat exchange can body that can perform heat exchange heating by using a single burner. The burner combustion control of the heat exchange can body is performed by feedforward control and feedback control, and a feedforward control value during operation. And a feedback control value, the burner burner is turned off once when the sum exceeds a certain value, and the burner is turned on again when the sum falls below a certain value. When the combustion of the burner is once turned off, the rotation speed of the blower fan is changed from the rotation speed during the burning operation to the rotation speed for ignition, and the rotation speed for ignition is made to stand by during the off period. It is the first feature in that it has a control unit which is adapted.
The one-can two-circuit hot water supply apparatus of the present invention also uses a single burner for two circuits, a bath reheating circuit for reheating water from a bathtub and a hot water supply circuit for heating and supplying hot water from a water supply system. If the temperature sensor of the heat exchange unit on the hot water supply circuit detects a certain temperature or higher during the bath reheating alone operation by the bath reheating circuit, A one-can, two-circuit water heater that turns off the burner and turns on the burner again when the temperature drops below a certain temperature, wherein the temperature sensor of the heat exchange unit on the hot water supply circuit side during the bath reheating alone operation. If the burner combustion is once turned off by detecting a certain temperature or higher, the control unit should change the rotation speed of the blower fan from the rotation speed during the combustion operation to the rotation speed for ignition and wait for standby. The second It is characterized.
[0006]
According to the first aspect of the present invention, during operation, the control unit calculates a sum of a feedforward (hereinafter abbreviated as FF) control value and a feedback (hereinafter abbreviated as FB) control value, and this is a certain value or more. Then, the combustion of the burner is once turned off, and the rotation speed of the blower fan is changed from the rotation speed during combustion to the rotation speed for ignition. As a result, during the temporary stoppage of the burner, the blower fan stands by while continuing to rotate at the rotation speed for ignition, and the rotation sound of the blower fan can be kept low.
When the control value (actually not output), which is inversely calculated from the actual hot water temperature, becomes lower than a certain value by turning off the burner combustion, the burner is turned on again. Thus, the igniter of the burner is driven, and fuel is supplied to the burner to ignite. Since the rotation speed of the blower fan at that time is the rotation speed for ignition, ignition can be performed immediately.
In the above description, the FF control value can be, for example, the number of FFs, and the FB control value can be the number of FBs. Here, the number means the amount of heat such that No. 1 raises 1 liter of water by 25 ° C. per minute. In the above description, the constant value in the expression of a certain value or more means that when the sum of the FF control value and the FB control value becomes larger, at least a part of the components of the heat exchange can body becomes overheated. It means a value such that the can is thermally damaged over time or non-time, and can be experimentally determined according to the type of the heat exchange can. In addition, the constant value in the expression “below the constant value” is given a temperature hysteresis as a value lower than the constant value in the expression not less than the constant value in principle.
In the above description, the burner is normally turned off by stopping the supply of fuel to the burner. The burner is normally turned on by the start of fuel supply to the burner and the start of an ignition operation by an igniter or the like.
Further, in the above description, the ignition rotation speed is a rotation speed smaller than the maximum rotation speed of the post-purge rotation speed or the rotation speed of the blowing fan during combustion, and is a rotation speed suitable for igniting the burner, and is experimentally determined. can do.
Further, according to the second aspect of the present invention, when the temperature sensor of the heat exchange unit on the hot water supply circuit side detects a certain temperature or higher during the bath reheating circuit alone operation by the bath reheating circuit, the burner is once turned on. Stopped. Thereby, it is possible to prevent the hot water supply circuit, through which water is not passed, from being overheated in the heat exchanging section or from boiling water. Then, when the burner combustion is temporarily turned off, the rotation speed of the blower fan is changed from the rotation speed during combustion to the rotation speed for ignition, and standby is performed, so that noise from the blower fan is prevented and the burner is temporarily turned off. It is possible to prevent a rapid decrease in the amount of heating heat generated when the heating is performed.
In the above description, the constant temperature in the expression that the temperature sensor of the heat exchange unit on the hot water supply circuit side detects a certain temperature or higher means that when the temperature becomes higher than that, the heat exchange unit on the hot water supply circuit side in a non-water supply state becomes overheated. Or a temperature at which water present inside the heat exchange section boils, and an appropriate temperature can be experimentally determined.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on embodiments.
FIG. 1 is an overall configuration diagram of a one-can, two-circuit water heater showing an embodiment of the present invention, and FIG. 2 is a flowchart showing a control mechanism of operation by a control unit. FIG. 3 is a flowchart showing another control mechanism of the operation by the control unit.
[0008]
The overall configuration of the one-can two-circuit water heater will be described with reference to FIG. Reference numeral 10 denotes a one-can two-circuit heat exchange can body having one blower fan 11 and one burner 12. The burner 12 includes a fuel spray nozzle 12a, an igniter 12b, and the like. Fuel is supplied to the spray nozzle 12a by a supply pump 12c through a supply control valve 12d.
In the upper space inside the heat exchange can 10, a heat exchange part 20a of the bath reheating circuit 20 and a heat exchange part 40a of the hot water supply circuit 40 are arranged.
The bath reheating circuit 20 transports bath water from a bathtub (not shown) to the heat exchange can 10 and conveys heat-exchanged hot water from the heat exchange can 10 to the bath. And a bath outgoing pipe 22.
The bath return pipe 21 is provided with a pressure sensor 31 for detecting a bathtub water level, a circulation pump 32, a water flow switch 33, and a bathtub temperature sensor 34, and a three-way valve 23 from the bath return pipe 21 to the bath outflow pipe 22. A bypass 24 is provided.
The hot water supply circuit 40 has a water inlet pipe 41 that conveys water from the water supply to the heat exchange can 10 and a hot water outlet pipe 42 that taps hot water heated by the heat exchange can 10. It is branched and extended to a pipe 43 and a bath automatic dropping pipe 44.
The water inlet pipe 41 is provided with a water amount sensor 51 and a water inlet temperature sensor 52, and the hot water pipe 42 is provided with a hot water temperature sensor 53. A bypass 46 is provided from the water inlet pipe 41 via a proportional control valve 45. A water amount adjusting valve 54 and a hot water supply temperature sensor 55 are provided downstream of the junction of the bypass 46.
At the end of the general hot water supply pipe 43, a general hot water supply curan 43a is provided, and the automatic bath water dropping pipe 44 is connected to the bath return pipe 21 via a drop valve unit 44a having a dropping water amount sensor, so that hot water is supplied to the bathtub. Automatic drop-in is possible.
[0009]
The heat exchange can body 10 is provided with a boiling prevention temperature sensor 60 at a bending section where the heat exchange section 40a of the hot water supply circuit 40 slightly comes out of the heat exchange can body 10. The temperature sensor 60 for preventing boiling is close to the burner 12 in the heat exchange section 20a of the bath reheating circuit 20 and the heat exchange section 40a of the hot water supply circuit 40, which are arranged in the heat exchange can 10, and is easily overheated. The sensor is disposed in the heat exchange section 40a on the hot water supply circuit 40 side and detects the internal water temperature. Further, overheat safety devices 61 and 62 are provided on the bath pipe 22 near the outside of the heat exchange can body 10 and the tapping pipe 42 near the outside of the heat exchange can body 10, respectively. These overheat safety devices 61 and 62 are devices for detecting the temperatures of the bath outflow pipe 22 and the tapping pipe 42 themselves to prevent the pipes 22 and 42 from being overheated.
Reference numeral 70 denotes a control unit which receives information from sensors provided in each unit of the apparatus, receives a command from a remote controller (not shown), calculates and determines based on built-in software, and outputs a predetermined command to each unit of the apparatus. I do.
[0010]
Explaining the control of the operation by the control unit 70, there are three cases of the operation: the hot water supply alone operation, the simultaneous operation of the hot water supply operation and the bath reheating operation, and the bath reheating operation alone. In any case, the burner 12 is also used.
The hot water supply independent operation is started when the water amount sensor 51 detects the minimum operating water amount or more by opening the general hot water supply curan 43a or the like while the main switch of the hot water supply operation is on. The controller 70 drives the blower fan 11, starts the ignition operation by the igniter 12b, opens the supply pump 12c, and ignites the spray fuel from the spray nozzle 12a. The control unit 70 sets the fuel supply amount at the time of ignition to an ignition amount, and the rotation speed of the blower fan 11 to the ignition rotation speed. When the operation is started, the control unit 70 calculates the required amount of combustion heat from the set tap water temperature, the temperature of incoming water from the incoming water temperature sensor 52, the amount of incoming water from the water amount sensor 51, and the like, and calculates the required amount of required combustion heat. FF control is performed as the FF control value. Then, the hot water temperature actually discharged and the set hot water temperature are compared, and the amount of combustion heat corresponding to the difference is subjected to FB control as an FB control value. The calculated amount of combustion heat can be calculated as the number of hot water outlets, and the FF control value and the FB control value can be calculated as the number of FF hot water outlets and the number of FB hot water outlets. The operation can be on-off combustion when the required amount of combustion heat (required hot water number) is equal to or less than a certain value, and can be continuous combustion when the required amount of heat exceeds that value.
When the general hot water supply curan 43a is closed during the hot water supply operation and the water amount sensor 51 becomes less than the minimum operating water amount, the control unit 70 stops the fuel supply, turns off the combustion of the burner 12, and rotates the fan 11 Is changed from the rotation speed during combustion to the post-purge rotation speed, and the rotation of the blower fan 11 is stopped after a certain post-purge time has elapsed. This ends the operation. The post-purge rotation speed can be set to the maximum rotation speed by the blower fan 11, whereby the exhaust gas is quickly cleared.
[0011]
Next, an operation control mechanism by the control unit 70 when the hot water supply operation and the bath reheating operation are performed simultaneously will be described. Simultaneous operation is performed when a further hot water supply operation is instructed during the hot water supply operation, or when a further hot water supply operation is instructed during the hot water supply operation. In the simultaneous operation, the combustion control is performed by the FF control and the FB control. Of course, the FF control value and the FB control value can be the FF outlet number and the FB outlet number, respectively. During operation, in principle, continuous combustion operation is performed, the number of FF outlets is fixed, and the outlet temperature on the hot water supply side is adjusted to the set outlet temperature by adjusting the number of FB outlets. Then, only when the sum of the number of FF hot water and the number of FB hot water during the continuous combustion operation is equal to or more than the fixed value Y, the burner 12 is temporarily turned off temporarily only during that time. The burner 12 is turned on again when the sum of the numbers falls below a certain value X lower than the certain value Y. When the sum of the number of FF hot water and the number of FB hot water becomes larger, the constant value Y becomes longer with time. For example, at least a part of the components of the heat exchange can 10 becomes overheated. Or a value that causes thermal damage over time or can be determined experimentally depending on the type of heat exchange can. In addition, the constant value X has a temperature hysteresis that is lower than the constant value Y in consideration of actual operation.
In the present invention, when the sum of the number of FF hot water and the number of FB hot water becomes equal to or more than the fixed value Y during the simultaneous operation, the combustion of the burner 12 is temporarily turned off. Does not change the rotation speed of the blower fan 11 from the rotation speed during combustion to the post-purge rotation speed, but to the ignition rotation speed.
That is, when further explained along FIG. 2, when the operation is the simultaneous operation of the hot water supply operation and the bath reheating operation (Yes in step S <b> 1), the control unit 70 determines the number of FF hot water and the number of FB hot water. It is monitored whether or not the sum becomes equal to or more than a fixed value Y (step S2). If the sum is equal to or more than the predetermined value Y (yes in step S2), the combustion of the burner 12 is turned off by stopping the fuel supply, and the air is blown. The number of revolutions of the fan 11 is changed from the number of revolutions during combustion to the number of revolutions for ignition (step S3), and a standby state is set. Then, the control unit 70 monitors that the sum of the FF hot water number and the FB hot water number drops to a certain value X or less (step S4), and when the sum falls below (yes in step S4), the igniter. The burner 12 is driven to supply fuel and turn on the burner 12 again (step S5). At this time, the amount of fuel supplied to the burner 12 is set to the amount of fuel supplied for ignition, and the fuel is ignited as it is by the rotation speed for ignition of the blower fan 11 in a standby state. After ignition, the burner 12 is burned at the calculated FF hot water number and FB hot water number, and the blower fan 11 is rotated at a rotation speed (rotation speed during combustion) according to the degree of the combustion (step). S6). When both the hot water supply operation and the bath reheating operation are stopped (Yes in step S7), the combustion of the burner 12 is stopped and the rotation speed of the blower fan 11 is changed from the rotation speed during combustion to the post-purge rotation speed. After the change (Step S8), and the post-purge time ends (Yes in Step S9), the driving of the blower fan 11 is stopped (Step S10). This ends the operation.
The rotation speed for ignition of the blower fan 11 is, for example, 3100 rotations, the post-purge rotation speed is 4660 rotations, which is the maximum rotation speed, and the rotation speed of the blower fan 11 during combustion is intermediate therebetween.
[0012]
Next, the case where the bath reheating alone operation is performed will be described. Now, when there is a bath reheating command from the remote controller, the controller 70 drives the circulation pump 32 and the blower fan 11, and opens the fuel supply pump 12c when the water flow switch 33 detects the minimum working water amount. Thus, the fuel sprayed from the spray nozzle 12a is ignited by the spark of the igniter 12b. Ignition is performed at a fuel supply amount for ignition and with the blower fan 11 at an ignition speed. After the ignition, the fuel supply amount and the number of rotation of the blast are increased to a predetermined number of rotations, and a steady combustion is started. In the bath reheating alone operation, usually, continuous combustion is performed at a constant number of hot water baths by FF control, and when the temperature reaches a set bathtub temperature, the operation is stopped by the control unit 70. To stop the operation, first, the fuel supply is stopped by the control unit 70, and at the same time, the rotation speed of the blower fan 11 is increased to the post-purge rotation speed, and is stopped after a predetermined time.
To further explain with reference to FIG. 3, when the operation is the bath-heating alone operation (Yes in step S11), the control unit 70 determines the temperature detected by the boiling prevention temperature sensor 60 provided on the hot water supply circuit 40 side. Is monitored to determine whether or not the temperature is equal to or higher than a predetermined temperature B (step S12). If the temperature is equal to or higher than the predetermined temperature B (YES in step S12), the combustion of the burner 12 is turned off by stopping the supply of fuel, and the blowing fan 11 is turned off. The number of revolutions is changed from the number of revolutions during combustion to the number of revolutions for ignition (step S13), and a standby state is set. Then, the control unit 70 monitors that the temperature detected by the boiling prevention temperature sensor 60 becomes equal to or lower than the predetermined temperature A (step S14), and when it becomes lower (yes in step S14), it drives the igniter 12b and fuel To turn on the burner 12 again (step S15). At this time, the amount of fuel supplied to the burner 12 is set to the amount of fuel supplied for ignition, and the fuel is ignited as it is by the rotation speed for ignition of the blower fan 11 in a standby state. After the ignition, the burner 12 is burned again by the FF control based on the fixed number, and the blower fan 11 is rotated at a fixed rotation number (the rotation number during combustion) corresponding to the fixed number (step S16). If both the bath reheating operation is stopped when the bathtub temperature reaches a predetermined temperature or when the bath reheating operation switch is turned off by the remote controller (Yes in step S17), the burner 12 is stopped. Is stopped, and the rotation speed of the blower fan 11 is changed from the rotation speed during combustion to the post-purge rotation speed (step S18). When the post-purge time ends (yes in step S19), the drive of the blower fan 11 is started. It stops (step S20). This ends the operation.
In the above description, the constant value A is set to a value lower than the constant value B to provide temperature hysteresis.
[0013]
【The invention's effect】
The present invention has the above-described structure, and according to the one-can two-circuit water heater according to the first aspect, when the sum of the feedforward control value and the feedback control value exceeds a certain value during operation, the burner combustion is temporarily stopped. In a one-can two-circuit water heater in which the burner is turned off and then turned on again when the burner is turned down to a certain value or less, if the combustion of the burner is once turned off during operation, the rotation speed of the blower fan is changed to the rotation during combustion operation. Since it has a control unit that changes from the number to the ignition rotation speed and makes it stand by during the off period at the ignition rotation speed,
Even if combustion of the burner is temporarily turned off during operation for the purpose of protecting the can body from an excessive load on the heat exchange can body such as overheating, noise of the blower fan generated each time can be prevented.
Further, each time the burner is turned on again after the temporary burn-off during the operation, it is not necessary to readjust the rotation speed of the blower fan to the rotation speed for ignition, and the re-ignition of the burner can be performed smoothly.
Further, according to the one-can two-circuit hot water supply device of the second aspect, when the temperature sensor of the heat exchange unit on the hot water supply circuit side detects a certain temperature or higher during the bath-only heating operation alone, the burner combustion is stopped during that time. In a one-can two-circuit water heater in which the burner is turned off when the temperature is lowered to a certain temperature or less, the burner is turned on again when the combustion of the burner is once turned off. Since it has a control unit that changes to the ignition speed and makes it stand by,
For the purpose of preventing the overheated hot water supply circuit from boiling during pauses, etc. Can be prevented.
Further, each time the burner is turned on again after the temporary burn-off during the operation, it is not necessary to readjust the rotation speed of the blower fan to the rotation speed for ignition, and the re-ignition of the burner can be performed smoothly.
Furthermore, when the burner combustion is temporarily stopped during the bath reheating alone operation, the temperature of the bathtub water circulating in the bath reheating circuit is reduced during the stop period, but the rotation speed of the blower fan is reduced. Since the number of revolutions for ignition is reduced, a decrease in the temperature of the circulating water can be suppressed to a small extent.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a one-can, two-circuit water heater showing an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an operation control mechanism of a control unit.
FIG. 3 is a flowchart showing another control mechanism of operation by the control unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Heat exchange body 11 Blower fan 12 Burner 20 Bath reheating circuit 20a Heat exchange unit 40 Hot water supply circuit 40a Heat exchange unit 60 Boiling prevention temperature sensor 70 Control unit

Claims (2)

A heat exchange can body capable of performing heat exchange and heating by using a single burner for two circuits, a bath reheating circuit for reheating water from a bathtub and a hot water supply circuit for heating and supplying hot water from a water supply system. The control of the burner of the heat exchange can body is performed by feedforward control and feedback control, and during the operation, the combustion of the burner is temporarily turned off when the sum of the feedforward control value and the feedback control value exceeds a certain value. A one-can two-circuit water heater in which the burner is turned on again when the burner drops to a certain value or less. Characterized by having a control unit for changing the number of revolutions from the number of revolutions to the number of revolutions for ignition and waiting at the number of revolutions for ignition during the OFF period. Apparatus. A heat exchange can body capable of performing heat exchange and heating by using a single burner for two circuits, a bath reheating circuit for reheating water from a bathtub and a hot water supply circuit for heating and supplying hot water from a water supply system. If the temperature sensor of the heat exchange unit on the hot water supply circuit detects a certain temperature or higher during the bath heating alone operation by the bath reheating circulation circuit, the burner combustion is turned off during that time, and if it drops below the certain temperature A one-can two-circuit water heater in which a burner is turned on again, wherein the temperature sensor of a heat exchange unit on the hot water supply circuit side detects a temperature equal to or higher than a certain temperature during the bath reheating alone operation, thereby burning the burner. A one-can, two-circuit hot water supply device comprising a control unit that, when turned off, changes the rotation speed of the blower fan from the rotation speed during the combustion operation to the rotation speed for ignition and waits.

Images