JP6277873B2 - boiler - Google Patents

Description

  The present invention relates to a boiler. More specifically, the present invention relates to a boiler that adjusts the amount of combustion air supplied to a burner by the output of a blower and the opening of a damper.

2. Description of the Related Art Conventionally, a boiler that includes a burner that burns fuel, a fuel supply device that supplies fuel to the burner, and a blower that supplies combustion air to the burner. The amount of air required for combustion varies accordingly. Therefore, in such a boiler, a damper is disposed in the combustion air flow path, and the flow rate of the combustion air supplied to the burner is controlled by adjusting the opening of the damper according to the combustion state.
In recent years, there has also been proposed a technique of supplying a more suitable amount of combustion air to the burner according to the combustion state by changing the output of the blower together with the opening of the damper (see, for example, Patent Document 1). .

JP 2006-145121 A

By the way, in a boiler having a damper, the operation of the damper is periodically checked. The operation check of the damper is performed, for example, by measuring a change in pressure of the combustion air before and after changing the opening of the damper. That is, when the pressure of the combustion amount air before and after the change in the opening degree of the damper is measured, and the amount of change in the pressure of the combustion air exceeds a predetermined value, the damper is operating normally. If the change amount is less than the predetermined value, it is determined that the operation of the damper is not normal.
Here, in the boiler in which the flow rate of the combustion air is controlled only by the opening degree of the damper, the operation of the damper can be confirmed by the above-described method. However, in a boiler in which the flow rate of combustion air is controlled by the opening of the damper and the output of the blower, the pressure of the combustion air also changes depending on the output of the blower. I can't.

  Therefore, an object of the present invention is to provide a boiler that can suitably determine a malfunction of a damper in a boiler that controls the flow rate of combustion air by the opening of the damper and the output of the blower.

  The present invention is a boiler capable of burning by changing a combustion state, and is disposed between a burner that burns fuel, a blower that supplies combustion air to the burner, the burner and the blower, and A damper that can be opened and closed at an opening in a range of, and a control unit that controls the opening of the damper and / or the output of the blower according to a change in the combustion state, and the control unit is controlled by the burner When starting combustion of fuel by the burner from a combustion stopped state where fuel combustion is stopped, a pre-purge control unit that operates the blower at a first output for a first time and sets the damper to a first opening degree. A first pressure acquisition unit that acquires a first pressure that is a pressure of combustion air in a control state by the pre-purge control unit, and after the first time has elapsed, the fan is operated at the first output. An ignition damper control unit that sets the damper to a second opening smaller than the first opening, and a second pressure that is a pressure of combustion air in a control state by the ignition damper control unit is acquired. A pressure acquisition unit; a determination unit that determines whether a difference between the first pressure and the second pressure exceeds a first threshold; and a difference between the first pressure and the second pressure by the determination unit. An ignition blower control unit that changes an output of the blower from the first output to a second output when it is determined that the first threshold is exceeded.

  Moreover, it is preferable that the first pressure acquisition unit and the second pressure acquisition unit acquire the pressure of combustion air on the downstream side of the damper.

  The control unit may further include an ignition control unit that starts ignition of the burner when the determination unit determines that the difference between the first pressure and the second pressure exceeds the first threshold value. It is preferable to provide.

  Moreover, the said control part is further provided with the 3rd pressure acquisition part which acquires the 3rd pressure which is the pressure of the combustion air after the output of the said air blower is changed to the said 2nd output by the said air blower control part at the time of ignition. The ignition control unit preferably starts ignition of the burner when a difference between the first pressure and the third pressure exceeds a second threshold value.

  Moreover, the said control part is further provided with the 3rd pressure acquisition part which acquires the 3rd pressure which is the pressure of the combustion air after the output of the said air blower is changed to the said 2nd output by the said air blower control part at the time of ignition. Preferably, the ignition control unit starts ignition of the burner when a difference between the second pressure and the third pressure exceeds a third threshold value.

  In addition, the control unit determines that the damper does not operate when the determination unit does not determine that the difference between the first pressure and the second pressure exceeds the first threshold for a second time. It is preferable to further include a non-operation notification unit that notifies

  Further, it is preferable that the malfunction notifying unit stops the operation of the boiler after notifying the malfunction of the damper.

  According to the boiler of the present invention, in a boiler that controls the flow rate of combustion air based on the opening degree of the damper and the output of the blower, it is possible to suitably determine the malfunction of the damper.

It is a figure showing typically one embodiment of the boiler of the present invention. It is a functional block diagram which shows the structure of the control part which concerns on 1st Embodiment. It is a timing chart which shows the operation | movement at the time of ignition of the boiler which concerns on 1st Embodiment of this invention. It is a functional block diagram which shows the structure of the control part which concerns on 2nd Embodiment.

Hereinafter, preferred embodiments of the boiler of the present invention will be described with reference to the drawings. First, a first embodiment of the boiler of the present invention will be described.
The boiler 1 of 1st Embodiment is a steam boiler which heats water and produces | generates a vapor | steam. As shown in FIG. 1, the boiler 1 includes a can body 10, a blower 20 that sends combustion air to the can body 10, and an air supply duct 30 that connects the can body 10 and the blower 20 and through which combustion air flows. A damper 40 disposed in the air supply duct 30, a pressure sensor 31 that detects the pressure inside the air supply duct 30, a fuel supply device 50 that supplies fuel gas to the air supply duct 30, and the can body 10. An exhaust pipe 60 through which the exhausted combustion gas flows, a water supply passage (not shown) for supplying water to the can body 10, and a control unit 70 for controlling the combustion state of the boiler 1 are provided.

As shown in FIG. 1, the can 10 includes a boiler housing 11, a plurality of water pipes 12, a lower header 13, an upper header 14, and a burner 15.
The boiler housing | casing 11 comprises the external shape of the can 10, and is formed in the rectangular parallelepiped shape of planar view. An air supply port 16 is formed in the first side surface 11a located on one end side in the longitudinal direction of the boiler casing 11, and a second side surface 11b located on the other end side in the longitudinal direction of the boiler casing 11 is An exhaust port 17 is formed.

The plurality of water pipes 12 are disposed so as to extend in the vertical direction inside the boiler housing 11 and are disposed at predetermined intervals in the longitudinal direction and the width direction of the boiler housing 11.
The lower header 13 is disposed at the lower part of the boiler casing 11. The lower header 13 is connected to the lower ends of the plurality of water pipes 12.
The upper header 14 is disposed on the upper portion of the boiler casing 11. The upper header 14 is connected to the upper ends of the plurality of water pipes 12.

The burner 15 is disposed in the air supply port 16. The burner 15 includes a main burner and a pilot burner (not shown individually).
The main burner burns a mixed gas of combustion air supplied from the blower 20 and fuel gas supplied from the fuel supply device 50.
The pilot burner is used at the time of ignition in which the main burner is ignited and combustion of the boiler 1 is started.

  The blower 20 includes a blower body 21 having a fan and a motor that rotates the fan, and an inverter 22 that increases or decreases the number of rotations of the fan (motor). The blower 20 feeds combustion air into the can body 10 with a predetermined output as the fan rotates at a predetermined rotation speed in accordance with the frequency input to the inverter 22.

The air supply duct 30 has an upstream end connected to the blower 20 and a downstream end connected to the air supply port 16. The air supply duct 30 supplies the combustion air sent from the blower 20 to the can body 10.
The damper 40 is in a closed state in which the combustion air flow path inside the air supply duct 30 is closed and rotated 90 degrees from this closed state to open the combustion air flow path in the air supply duct 30. It is arranged to be rotatable between states.

  The pressure sensor 31 is arranged on the downstream side of the damper 40 in the air supply duct 30. The pressure sensor 31 detects the pressure of combustion air that circulates downstream of the damper 40 in the air supply duct 30. In the present embodiment, the pressure sensor 31 measures the pressure of the combustion air (wind pressure) with a pressure-sensitive element, converts it into an electrical signal, and outputs it to the control unit 70 as a voltage value.

The fuel supply device 50 includes a main gas supply line 51, shutoff valves 52a and 52b and nozzles 53 provided in the main gas supply line 51, a pilot gas supply line 54, and a pilot burner provided in the pilot gas supply line 54. And a valve 55.
The main gas supply line 51 is connected to the downstream side of the supply duct 30 from the position where the damper 40 is disposed, and supplies the fuel gas to the supply duct 30. In the present embodiment, two main gas supply lines 51 are provided in parallel and joined to the air supply duct 30 after merging at the tip side.

The shut-off valves 52a and 52b are constituted by electromagnetic valves, and are arranged on the two main gas supply lines 51, respectively. These shut-off valves 52 a and 52 b adjust the amount of fuel gas supplied to the air supply duct 30 by opening or shutting off the flow path of the main gas supply line 51.
The nozzle 53 is disposed at the front end of the main gas supply line 51 and ejects fuel gas inside the air supply duct 30.

The pilot gas supply line 54 is connected to a pilot burner and supplies fuel gas to the pilot burner.
The pilot burner valve 55 is configured by an electromagnetic valve, and opens or blocks a flow path to the pilot burner in the pilot gas supply line 54.

  The exhaust tube 60 is connected to the exhaust port 17. The exhaust cylinder 60 discharges the combustion gas generated by the combustion of the fuel gas inside the can 10.

  According to the boiler 1 described above, the combustion air sent into the air supply duct 30 by the blower 20 is mixed with the fuel gas supplied from the main gas supply line 51, and the mixed gas of the fuel gas and the combustion air is mixed. It is ejected from the burner 15 into the inside of the can 10 and burned. And the water supplied with the combustion of the mixed gas by the burner 15 heats the water supplied from the lower header 13 to the inside of the plurality of water pipes 12, and generates steam. The steam generated in the plurality of water pipes 12 is collected in the upper header 14 and then led to the outside through a steam outlet pipe (not shown). Further, the combustion gas generated by the combustion of the mixed gas is discharged from the exhaust cylinder 60 to the outside.

Next, details of the control of the combustion state of the boiler 1 by the control unit 70 will be described.
The controller 70 controls the combustion state (combustion rate) of the boiler 1 by controlling the supply amount of combustion air and the supply amount of combustion gas to the can body 10 and adjusts the amount of steam generated by the boiler 1. To do.
More specifically, the control part 70 changes the combustion state of the boiler 1 according to the consumption of the steam by the load apparatus which the boiler 1 supplies steam, and adjusts the production amount of steam.

The boiler 1 of the present embodiment is configured by a stage value control boiler (three-position control boiler) capable of burning by changing the combustion rate stepwise at three combustion positions of a combustion stop position, a low combustion position, and a high combustion position. Is done.
And the control part 70 changes the output of the air blower 20 and / or the opening degree of a damper according to each combustion position, and controls the flow volume of the combustion air supplied to the burner 15. FIG. Specifically, the output of the blower 20 when the boiler 1 is burned at the high combustion position is set higher than the output of the blower 20 when burned at the low combustion position.
Further, the control unit 70 opens and closes the shut-off valves 52 a and 52 b according to the combustion state, and controls the flow rate of the combustion gas supplied to the burner 15. In the present embodiment, when the boiler 1 is burned at the low combustion position, one of the shutoff valve 52a or the shutoff valve 52b is opened, and when the boiler 1 is burned at the high combustion position, the shutoff valve 52a and The shut-off valve 52b is opened.

  Further, in the present embodiment, the control unit 70 causes the malfunction of the damper 40 when starting combustion of fuel by the burner 15 from a combustion stop state in which combustion of fuel by the burner 15 (main burner and pilot burner) is stopped. The damper operation determination control for determining

  That is, when combustion by the burner 15 is started from a combustion stopped state, a pre-purging step for ventilating the inside of the can 10 (boiler casing 11), a pre-type that generates a flame that forms a flame in the burner 15 (pilot burner). An ignition process, an ignition trial process for igniting the pilot burner, a pilot-only process for extinguishing the type of fire and burning only the pilot burner, and a main trie process for igniting the main burner are performed (see FIG. 3). Hereinafter, the pre-ignition process, the ignition try process, the pilot-only process, and the main try process are collectively referred to as an ignition process.

  Here, in the pre-purge process, a large amount of combustion air is supplied to the inside of the can body 10 for the purpose of ventilating the inside of the can body 10 in a short time, while in the ignition process, flame formation is stably performed. In order to do so, it is necessary to limit the supply amount of combustion air as compared with the case of pre-purge. In this embodiment, the malfunction of the damper 40 is determined using the timing of the decrease in the supply amount of combustion air when the burner 15 is ignited from this pre-purge.

  As a configuration for executing the above damper operation determination control, as shown in FIG. 2, the control unit 70 includes a pre-purge control unit 71, a first pressure acquisition unit 72, an ignition damper control unit 73, and a second The pressure acquisition part 74, the determination part 75, the blower control part 76 at the time of ignition, the ignition control part 77, and the non-operation alerting | reporting part 78 are provided.

  When starting combustion by the burner 15 from the combustion stopped state, the pre-purge control unit 71 performs pre-purge for a first time (for example, 15 seconds) to ventilate the inside of the can body 10 (boiler casing 11). Specifically, the pre-purge control unit 71 operates the blower 20 with the first output and sets the damper 40 to the first opening. In the present embodiment, the first output is set higher than the output when the boiler 1 is burned at the low combustion position. The first opening is set to an opening at which the combustion air flow path inside the air supply duct 30 is opened. Thereby, the time required for pre-purge can be shortened.

  The first pressure acquisition unit 72 acquires the first pressure that is the pressure of the combustion air detected by the pressure sensor 31 on the downstream side of the damper 40 in the control state by the pre-purge control unit 71.

  The ignition damper control unit 73 changes the damper 40 from the first opening to a second opening smaller than the first opening while operating the blower 20 at the first output after the first time has elapsed. . That is, when the pre-purge is completed by the pre-purge control unit 71, the ignition damper control unit 73 reduces the opening degree of the damper 40 without reducing the output of the blower 20, and reduces the combustion air flowing to the burner 15 side. Reduce the flow rate.

  The second pressure acquisition unit 74 acquires a second pressure that is the pressure of the combustion air detected by the pressure sensor 31 on the downstream side of the damper 40 in the control state by the ignition damper control unit 73.

  The determination unit 75 determines whether or not the difference between the first pressure and the second pressure exceeds a first threshold (for example, 25 mmAq). That is, when the opening degree of the damper 40 is reduced while the output of the blower 20 is maintained by the ignition damper control unit 73 (that is, when the flow path of the combustion air is narrowed), the pressure sensor 31 detects it. The second pressure to be applied should be smaller than the first pressure. Therefore, the determination unit 75 can determine whether or not the damper 40 has operated by determining whether or not the difference between the first pressure and the second pressure exceeds the first threshold value.

  In the present embodiment, the determination unit 75 outputs the output voltage V2 (second pressure) of the pressure sensor 31 acquired by the second pressure acquisition unit 74 and the output voltage of the pressure sensor 31 acquired by the first pressure acquisition unit 72. Compared with V1 (first pressure), it is determined whether or not the state of voltage value (for example, 0.1 V) corresponding to V1−V2> first threshold value continues for a predetermined time (for example, 1 second).

The on-ignition blower control unit 76 reduces the output of the blower 20 from the first output to the first output when the determination unit 75 determines that the difference between the first pressure and the second pressure exceeds the first threshold. Change to the second output. In the present embodiment, the second output is set to a value smaller than the first output and larger than the output when the boiler 1 is burned at the low combustion position.
The ignition control unit 77 starts ignition of the burner 15 when the determination unit 75 determines that the difference between the first pressure and the second pressure exceeds the first threshold value.

That is, if the determination unit 75 determines that the difference between the first pressure and the second pressure exceeds the first threshold, it can be said that the damper 40 is operating normally. Therefore, when the operation of the damper 40 is confirmed, the blower control unit 76 at the time of ignition lowers the output of the blower 20 to the second output and adjusts the supply amount of the combustion air to the burner 15 to a more suitable flow rate. .
In addition, the ignition control unit 77 generates a fire type and starts the preignition process.
In addition, a flame can be formed more stably in an ignition process by adjusting the supply amount of combustion air by both the opening degree of the damper 40 and the output of the blower 20.

When the determination unit 75 does not determine that the difference between the first pressure and the second pressure has exceeded the first threshold, the non-operation notification unit 78 is the damper 40. Notify the malfunction.
In addition, the non-operation notification unit 78 notifies the non-operation of the damper 40 and then stops the operation of the boiler 1.
That is, if the pressure of the combustion air detected by the pressure sensor 31 does not decrease after a certain period of time after the damper 40 is set to the second opening by the ignition damper control unit 73, the damper 40 is considered not operating normally. Therefore, the non-operation notification unit 78 determines that the damper 40 is not operating when the determination unit 75 does not determine that the difference between the first pressure and the second pressure exceeds the first threshold value for the second time. Notify by an alarm. Further, the operation of the boiler 1 is stopped.
Thereby, when there is a malfunction in the damper 40, the operation of the boiler 1 is stopped before the combustion of the burner 15 is started.

Next, the operation | movement at the time of ignition of the boiler 1 of this embodiment is demonstrated, referring FIG. FIG. 3 is a timing chart showing the operation when the boiler 1 is ignited.
As shown in FIG. 3, combustion in the combustion-stopped boiler 1 is started through a pre-purge process, a pre-ignition process, an ignition try process, a pilot-only process, and a main try process.

  In the pre-purge process, the pre-purge control unit 71 operates the blower 20 at the first output (here, the purge frequency) for the first time, and sets the damper 40 to the first opening (opening H) (t0 to 0). t1). Thereby, the inside of the can 10 is ventilated. In this state, the first pressure acquisition unit 72 acquires the first pressure.

When the first time has elapsed (t1), the ignition damper control unit 73 changes the damper 40 from the first opening to the second opening (opening L) while operating the blower 20 at the first output. To do.
When the opening degree of the damper 40 is changed to the second opening degree by the ignition damper control unit 73, the second pressure acquisition unit 74 acquires the second pressure. And the determination part 75 determines whether the difference of a 1st pressure and a 2nd pressure exceeded the 1st threshold value.

  When the determination unit 75 determines that the difference between the first pressure and the second pressure exceeds the first threshold (t2), the blower control unit 76 during ignition changes the output of the blower 20 from the first output to the first output. Less than the second output (ignition frequency). Here, the ignition control unit 77 generates a fire type by an ignition device (ignition transformer) (preignition process).

  In addition, after the opening degree of the damper 40 is changed to the second opening degree by the ignition damper control unit 73, it is determined that the difference between the first pressure and the second pressure exceeds the first threshold value for the second time. If not, the malfunction notification unit 78 informs the malfunction of the damper 40 by an alarm or the like, and stops the operation of the boiler 1.

When a predetermined time elapses after generating the fire type (t3), the ignition control unit 77 opens the pilot burner valve 55 to ignite the pilot burner (ignition try process).
When a predetermined time has elapsed since the pilot burner ignited (t4), the ignition control unit 77 extinguishes the fire type. Thereby, only a pilot burner will combust (pilot only process).
When a predetermined time elapses after the fire type is extinguished (t5), the ignition control unit 77 opens the shutoff valve 52a or the shutoff valve 52b to ignite the main burner. Further, the ignition control unit 77 keeps the pilot burner valve 55 open and continues combustion of the pilot burner (main trie).

  Thereby, the combustion of the burner 15 is started, and then, according to the combustion state, the control unit 70 controls the opening degree of the damper 40 and the output of the blower 20 to control the amount of combustion air supplied to the burner 15. To do.

  According to the boiler 1 of 1st Embodiment demonstrated above, there exist the following effects.

  (1) When the combustion of the boiler 1 in the effective combustion stop state is started, pre-purge for ventilating the inside of the boiler 1 is performed before the burner 15 is ignited. In this pre-purge, in order to perform ventilation in a short time, a larger amount of combustion air is supplied into the boiler 1 than during ignition. Therefore, in the boiler 1, the blower 20 is operated at the first output at the start of combustion, the pre-purge control unit 71 performs the pre-purge with the damper 40 as the first opening, and the blower 20 is operated at the first output after the pre-purge. An ignition damper control unit 73 that sets the damper 40 to the second opening, a first pressure that is the pressure of combustion air in the pre-purge state, and a second that is the pressure of combustion air in the control state by the ignition damper control unit 73 The ignition blower control unit 76 is configured to change the output of the blower 20 to the second output when the difference with the pressure exceeds the first threshold value. As a result, the pressure change due to the change in the opening degree of the damper 40 can be measured by reducing the opening degree of the damper 40 without changing the output of the blower 20 at the stage before the end of the pre-purge and before starting the ignition. Therefore, in the boiler 1 in which the flow rate of the combustion air is controlled by the opening degree of the damper 40 and the output of the blower 20, it is possible to suitably determine the malfunction of the damper 40. Further, since the operation of the damper 40 can be confirmed at the timing from pre-purge to reduce the flow rate of the combustion air in the state before the start of combustion to ignition, the combustion control of the boiler 1 is not hindered.

  (2) The first pressure acquisition unit 72 and the second pressure acquisition unit 74 are made to acquire the pressure of the combustion air on the downstream side of the damper 40 as the first pressure. Thereby, in addition to confirming the operation of the damper 40, the amount of change in the flow rate (air volume) of the combustion air on the downstream side of the damper 40 is also detected.

  (3) The control unit 70 includes an ignition control unit 77 that starts ignition of the burner 15 when the determination unit 75 determines that the difference between the first pressure and the second pressure exceeds the first threshold value. did. Thereby, the operation of the damper 40 is confirmed, and ignition of the burner 15 can be started in a state where the supply amount of the combustion air is appropriate. Therefore, after confirming the operation of the damper 40, the combustion of the boiler 1 can be suitably started.

  (4) The control unit 70 notifies the malfunction of the damper 40 when the determination unit 75 does not determine that the difference between the first pressure and the second pressure exceeds the first threshold for the second time. The non-operation notification unit 78 is configured to be included. Thereby, since the malfunction of the damper 40 can be confirmed before combustion of the boiler 1 is started, the safety of the boiler 1 can be improved.

  (5) The operation of the boiler 1 is stopped after notifying the non-operation notification unit 78 of the non-operation of the damper 40. Thereby, when the malfunction of the damper 40 is confirmed, the operation of the boiler 1 is stopped, so that it is possible to prevent the boiler 1 in which the malfunction has occurred in the damper 40 from being burned. Therefore, the safety of the boiler 1 can be further improved.

Next, 2nd Embodiment of the boiler of this invention is described, referring FIG. In the description of the second embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted or simplified.
The boiler of the second embodiment is different from the first embodiment in that the control unit 70 includes a third pressure acquisition unit 79.

The 3rd pressure acquisition part 79 acquires the 3rd pressure which is the pressure of the combustion air after the output of the air blower 20 is changed into the 2nd output by the air blower control part 76 at the time of ignition.
In the second embodiment, the ignition control unit 77 determines that the difference between the first pressure and the second pressure exceeds the first threshold by the determination unit 75, and in addition, the first pressure and the third pressure. When the difference exceeds a second threshold value (for example, 50 mmAq), ignition to the burner 15 is started, that is, the pre-ignition process is started. That is, in the second embodiment, the ignition control unit 77 starts the ignition to the burner 15 when the operation of the damper 40 is confirmed and the decrease in the output of the blower 20 is confirmed.

  Note that the ignition control unit 77 determines that the difference between the first pressure and the second pressure exceeds the first threshold by the determination unit 75, and that the difference between the second pressure and the third pressure is the third threshold. If it exceeds (for example, 25 mmAq), ignition to the burner 15 may be started.

  According to the boiler of 2nd Embodiment demonstrated above, there exist the following effects other than the effect of (1)-(5) mentioned above.

  (6) The control unit 70 includes a third pressure acquisition unit 79 that acquires the third pressure of the combustion air after the output of the blower 20 is changed to the second output by the ignition blower control unit 76. The ignition control unit 77 starts ignition of the burner 15 when the difference between the first pressure (or the second pressure) and the third pressure exceeds the second threshold (third threshold). Thereby, when the operation of the damper 40 is confirmed and a decrease in the output of the blower 20 is confirmed, the ignition to the burner 15 is started, so that the boiler 1 can be ignited more safely.

As mentioned above, although each preferred embodiment of the boiler of the present invention was described, the present invention is not restricted to the embodiment mentioned above and can be changed suitably.
For example, in the present embodiment, the present invention is applied to a step value control boiler, but is not limited thereto. That is, the present invention may be applied to a proportional control boiler that can continuously change the combustion rate.

In the present embodiment, the first pressure acquisition unit 72 and the second pressure acquisition unit 74 are made to acquire the pressure of the combustion air on the downstream side of the damper 40 as the first pressure. However, the present invention is not limited to this. That is, the pressure sensor is arranged on the upstream side of the damper in the air supply duct, and the first pressure acquisition unit and the second pressure acquisition unit are made to detect the pressure of the combustion air flowing through the upstream side of the damper in the air supply duct. Also good.
Further, pressure sensors are arranged on the upstream side and the downstream side of the damper in the air supply duct, and the pressure on the upstream side and the pressure on the downstream side of the damper in the intake duct are respectively connected to the first pressure acquisition unit and the second pressure acquisition unit. May be detected as the first pressure and the second pressure.

DESCRIPTION OF SYMBOLS 1 Boiler 15 Burner 20 Blower 40 Damper 70 Control part 71 Prepurge control part 72 1st pressure acquisition part 73 Ignition damper control part 74 2nd pressure acquisition part 75 Judgment part 76 Ignition blower control part 77 Ignition control part 78 Non-operation notification Part 79 Third pressure acquisition part

Claims (7)

A boiler capable of burning under different combustion conditions,
A burner that burns fuel;
A blower for supplying combustion air to the burner;
A damper that is disposed between the burner and the blower, and that can be opened and closed at a predetermined range of opening;
A control unit for controlling the opening of the damper and / or the output of the blower according to the change in the combustion state,
The controller is
When combustion of fuel by the burner is started from a combustion stop state in which combustion of fuel by the burner is stopped, the blower is operated at a first output for a first time and the damper is pre-purged at a first opening degree. A pre-purge control unit for performing
A first pressure acquisition unit that acquires a first pressure that is a pressure of combustion air in a control state by the pre-purge control unit;
After the first time has elapsed, an ignition-time damper control unit that sets the damper to a second opening smaller than the first opening while operating the blower at the first output;
A second pressure acquisition unit that acquires a second pressure that is a pressure of combustion air in a control state by the ignition damper control unit;
A determination unit that determines whether a difference between the first pressure and the second pressure exceeds a first threshold;
When the determination unit determines that the difference between the first pressure and the second pressure exceeds the first threshold value, the second output is smaller than the first output from the first output. A boiler having an ignition-time blower control unit to be changed to   The boiler according to claim 1, wherein the first pressure acquisition unit and the second pressure acquisition unit acquire the pressure of combustion air on the downstream side of the damper.   The said control part is further provided with the ignition control part which starts the ignition to the said burner, when it determines with the difference of the said 1st pressure and the said 2nd pressure exceeding the said 1st threshold value by the said determination part. Item 3. The boiler according to item 1 or 2. The control unit further includes a third pressure acquisition unit that acquires a third pressure that is a pressure of combustion air after the output of the blower is changed to the second output by the ignition blower control unit.
The boiler according to claim 3, wherein the ignition control unit starts ignition of the burner when a difference between the first pressure and the third pressure exceeds a second threshold value. The control unit further includes a third pressure acquisition unit that acquires a third pressure that is a pressure of combustion air after the output of the blower is changed to the second output by the ignition blower control unit.
The boiler according to claim 3, wherein the ignition control unit starts ignition of the burner when a difference between the second pressure and the third pressure exceeds a third threshold value.   The control unit notifies the malfunction of the damper when the determination unit does not determine that the difference between the first pressure and the second pressure exceeds the first threshold for a second time. The boiler in any one of Claims 1-5 further equipped with the non-operation alerting | reporting part to make.   The boiler according to claim 6, wherein the non-operation notification unit notifies the non-operation of the damper and then stops the operation of the boiler.

Images