JP3335282B2 - Air volume adjustment method using boiler inverter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the air volume of a boiler in which the air volume is adjusted by combining a blower for adjusting the rotation speed of a blower motor using an inverter device and a damper for adjusting the air flow from the air blower. It is about.

[0002]

2. Description of the Related Art As a method of adjusting the amount of air supplied to a burner of a boiler, a damper is provided between a blower and a burner, and an opening degree of the damper is adjusted, or an inverter device is connected to a blower motor. In addition, a method has been proposed in which the rotation speed of a blower motor is changed by an inverter device to adjust the air volume. When airflow is adjusted using an inverter device, the effect of reducing power consumption and noise can be obtained by lowering the rotation speed of the blower motor. When ignited, the ignition shock propagates to the blower. Therefore, it is necessary to increase the rotation speed of the blower motor and to restrict the air volume by a damper at the time of ignition, as described in JP-A-8-159449. It has been proposed to reduce the rotation speed of the blower motor and open the damper with a predetermined delay.

However, if it is set so that the damper is opened mechanically after a predetermined time has passed after instructing the inverter device of the blower motor to change the frequency, the airflow actually sent to the burner is not detected. Therefore, when switching the air volume adjusting means from the damper to the inverter device, the air volume balance may be lost, and the air volume may become too large or too small.

[0004]

The problem to be solved by the present invention is that in a boiler in which the amount of air is restricted by a damper at the time of ignition and then the amount of air is adjusted by an inverter device, the balance of the amount of air when switching the air amount adjusting means is obtained. The purpose of the present invention is to prevent collapsing.

[0005]

A blower in which an inverter device in which a purge frequency and a low combustion frequency are set is connected to a blower motor, and the air flow is adjusted by the inverter device.
A boiler provided with a wind pressure detecting device for detecting the wind pressure of the blower and a damper for limiting the air flow from the blower in the middle of the wind path for sending the air from the blower to the burner, and from the inverter device to the blower motor at the time of ignition. The frequency to be sent is the frequency for purging, and the damper is set to the ignition position to ignite in a state where the air volume is limited by the damper, and after ignition, the damper is opened to a normal opening and the air volume is adjusted by the inverter device In the boiler, when a set time has elapsed from ignition, a command is sent to the inverter device to change the operating frequency of the blower motor to a low combustion frequency,
Thereafter, when the wind pressure value detected by the wind pressure detecting device reaches the damper switching set value, the damper is opened to a normal opening.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a time chart showing the state of combustion and air volume adjustment in one embodiment of the present invention, and FIG. 2 is a configuration diagram of one embodiment of the present invention. The boiler 1 is provided with a burner 2 at an upper part, and combustion is performed by fuel sent through a fuel supply pipe 3 and combustion air sent from a blower 6. The change in the combustion amount is performed by adjusting the fuel supply amount and the air flow amount. The fuel supply amount is controlled by a first solenoid valve 4 and a second solenoid valve 5 provided in the fuel supply pipe 3. When the solenoid valve 4 and the second solenoid valve 5 are closed, combustion is stopped. When only the first solenoid valve 4 is opened, low combustion, the first combustion is stopped.
When the solenoid valve 4 and the second solenoid valve 5 are opened, high combustion occurs. The blower motor 7 is connected to an inverter 8 that sets a purge frequency, a high combustion frequency, and a low combustion frequency, and the rotation speed of the blower motor 7 is determined by the operating frequency output from the inverter 8. Is changed. A damper 9 is provided in the wind path connecting the blower 6 and the boiler 1.
Is provided, and the opening degree of the damper 9 is set to a fully open position, an ignition position, and a fully closed position. Further, a wind pressure detecting device 11 for detecting the wind pressure of the air sent to the burner 2 is provided on the wind path. The combustion control such as opening and closing of the first solenoid valve 4 and the second solenoid valve 5 and the air volume adjustment by the inverter 8 or the damper 9 are performed by the burner 2, the first solenoid valve 4, the second solenoid valve 5, the inverter 8, the damper 9. Is performed by the control device 10 connected to the wind pressure detection device 11.

Next, control performed by the control device 10 will be described. When the operation switch of the stopped boiler is turned on, the control device 10 fully opens the damper 9 to perform the pre-purge, and a command of the purge frequency is sent to the inverter device 8. The amount of air sent to the burner 2 increases as the rotation speed of the blower motor 7 increases, and the wind pressure also increases to the purge wind pressure value. When the pre-purge for ventilating the inside of the furnace of the boiler is completed, the opening degree of the damper 9 is changed to the ignition position, and the flow rate is reduced by the damper 9 without changing the rotation speed of the blower motor 7. When the damper 9 is set to the ignition position, the flow of air is restricted, so that the wind pressure value detected by the wind pressure detecting device also decreases. With the air volume adjusted by the damper, a voltage is applied to the ignition transformer to generate a spark, and the first solenoid valve 4 is opened to ignite with low combustion.
When a set time (for example, 10 seconds) elapses after ignition, a command for a low combustion frequency is input to the inverter device 8, and the inverter device 8 changes the operation frequency output to the blower motor 7 from the purge frequency to the low combustion frequency. Start migration.
The rotation speed of the blower motor 7 gradually decreases, and as the rotation speed decreases, the pressure of the air sent to the burner 2 also decreases. The wind pressure is detected by the wind pressure detecting device 11, and when the wind pressure value reaches the damper switching set value, the opening degree of the damper 9 starts to be fully opened. When the damper 9 is fully opened, the air flow increases, so that the wind pressure detected by the wind pressure detecting device 11 once increases, and thereafter decreases again in accordance with a decrease in the rotation speed of the blower motor 7.

When the air volume adjusting means is switched, the damper is fully opened when the wind pressure sent to the burner 2 reaches the damper switching set value, so that the wind pressure does not drop below the damper switching set value. , The minimum value of the air volume is determined. Further, when the point at which the operation of the damper is started is determined, the maximum value of the air flow at the time when the damper is fully opened is also determined. for that reason,
By setting the damper switching set value so that the deviation between the target air volume and the actual air volume is not biased to one side, it is possible to prevent the air volume from becoming too large or too small.

FIGS. 3 and 4 show another embodiment of the present invention, in which a wind pressure detecting device 11 is provided between a blower 6 and a damper 9. In this case, the damper switching set value is set to a value higher than the wind pressure value during low combustion. Control device 10
The control performed by will be described. When the operation switch of the stopped boiler is turned on, the control device 10 fully opens the damper 9 to perform the pre-purge, and a command of the purge frequency is sent to the inverter device 8. The amount of air sent to the burner 2 increases as the rotation speed of the blower motor 7 increases, and the wind pressure also increases to the purge wind pressure value. When the prepurge is completed, the opening degree of the damper 9 is changed to the ignition position, and the flow rate is reduced by the damper 9 without changing the rotation speed of the blower motor 7. Even when the damper 9 is set to the ignition position, the wind pressure value detected by the wind pressure detecting device 11 upstream of the damper 9 does not change, but the amount of air sent to the burner 2 decreases because the flow of air is restricted. . With the air volume adjusted by the damper, a voltage is applied to the ignition transformer to generate a spark, and the first solenoid valve 4 is opened to ignite with low combustion. When a set time has elapsed since the ignition, a command for a low combustion frequency is input to the inverter device 8, and the inverter device 8 starts shifting the operating frequency output to the blower motor 7 from the purge frequency to the low combustion frequency.
The rotation speed of the blower motor 7 gradually decreases, and as the rotation speed decreases, the pressure of the air sent to the burner 2 also decreases. The wind pressure is detected by the wind pressure detecting device 11, and when the wind pressure value reaches the damper switching set value, the opening degree of the damper 9 starts to be fully opened. Since the switching of the air volume adjusting means is performed at a predetermined wind pressure, the damper switching set value is determined so that the deviation between the target air volume and the actual air volume is not biased to one side, so that the air volume becomes too large, It can be prevented that the amount becomes too small.

Although not shown in the figure, in the case of performing high combustion after starting combustion with low combustion, the rotation speed of the blower motor is increased by inputting a high combustion frequency command to the inverter device 8. Then, the combustion is increased by opening the second solenoid valve 5, and thereafter, the fuel supply amount is changed by opening and closing the second solenoid valve 5, and the rotation speed of the blower motor 7 is changed to change the fuel supply to the burner 2. The combustion amount is changed by adjusting the air volume. Also, when stopping the boiler,
The solenoid valve is closed to extinguish the flame, a command of the purge frequency is sent to the inverter device 8, post-purging is performed, and when the post-purging is completed, the blower motor 7 is stopped and the damper 9 is stopped.
Is fully closed.

[0011]

By implementing the present invention, it is possible to prevent the balance of the air volume from being lost when the air volume adjusting means is switched immediately after ignition.

[Brief description of the drawings]

FIG. 1 is a time chart of an embodiment of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is a time chart of another embodiment of the present invention.

FIG. 4 is a configuration diagram of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler 2 Burner 3 Fuel supply pipe 4 First solenoid valve 5 Second solenoid valve 6 Blower 7 Blower motor 8 Inverter device 9 Damper 10 Control device 11 Wind pressure detection device

Continuation of front page (56) References JP-A-8-303759 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23N 3/08 F23N 5/20

Claims (1)

(57) [Claims] 1. An air blower for adjusting an air flow rate by connecting an inverter device to which a purge frequency and a low combustion frequency are set to a blower motor and adjusting the air volume by the inverter device, and a blower in the middle of a wind path for sending air from the blower to a burner. A boiler provided with a wind pressure detecting device for detecting the wind pressure of the boiler and a damper for limiting the amount of air from the blower, wherein the frequency sent from the inverter device to the blower motor at the time of ignition is a purge frequency, and the damper is an ignition position. Ignition is performed in a state where the air flow is restricted by the damper, and after ignition, the damper is opened to the normal opening, and in the boiler that adjusts the air flow with the inverter device, when the set time has elapsed from the ignition, the inverter device It sends a command to change the operating frequency of the blower motor in the low combustion frequency Te, then the blower motor
The boiler inverter device is characterized in that the damper is opened to a normal opening when the wind pressure value detected by the wind pressure detection device reaches the damper switching set value while the rotation speed of the motor is being reduced. Air flow adjustment method.