JPH0411763B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a safety device for a combustor, for example, a combustor for supplying hot water, and more specifically, a safety device for a combustor that stops combustion when a blower fan rotates abnormally during combustion. , relates to a safety device that performs safe operation.

<Conventional technology> Conventionally, in combustors for hot water supply, etc., abnormal rotation of the blower fan during combustion has been detected by detecting abnormal rotation of the blower fan when the rotation speed is below a certain level, regardless of the increase or decrease in the fuel supply amount and fan rotation speed due to adjustment of the combustion amount. rotation speed, e.g.
When the rotation speed was below 850 rpm, this was considered to be an abnormal rotation and combustion was stopped.

<Problems to be Solved by the Invention> However, in the combustor of the prior art described above, when the combustion amount is set to a strong state, for example, the rotational speed of the blower fan should increase accordingly;
In reality, there were cases in which the abnormal rotation continued at such low speeds (for example, slightly faster than the aforementioned 850 rpm) that the safety operation did not work. In such cases, conventional devices do not determine that there is an abnormality, so even if incomplete combustion occurs in the combustor, there is a problem in that it cannot be detected from the blower fan system. In other words, there was a problem in that a substantial failure of the blower fan system could not be detected.

<Purpose> Therefore, the present invention solves the drawbacks of the above-mentioned prior art, and makes it possible to control the number of rotations of the blower fan even when it is virtually impossible to control the rotational speed at which the blower fan should be rotated. The purpose of the present invention is to provide a combustor safety device that can detect an abnormality and perform safe operation of the combustor.

<Means for Solving the Problems> The present invention is a safety device for a combustor in which the rotational speed of a blower fan is automatically increased or decreased in response to an increase or decrease in the amount of fuel supplied due to adjustment of the combustion amount,
The basic feature is that when the difference between the fan rotation speed that is automatically set according to the fuel supply amount and the actual fan rotation speed exceeds a certain level, combustion is stopped and a safe operation is performed. .

<Function> The amount of fuel supplied is increased or decreased as the amount of combustion is adjusted. At the same time, the rotation speed of the ventilation fan is automatically set to the corresponding rotation speed. After setting, the set rotation speed and the actual fan rotation speed are compared, and if the difference is greater than a certain value, combustion is stopped and a safe operation is performed. Here, the safe operation refers to the termination of combustion, the operation of the abnormality reporting means, and the like. In the present invention, since the rotation speed of the fan at which the safe operation is performed is changed in response to a change in the set rotation speed of the blower fan, the safety operation in response to an abnormality of the blower fan can be performed more precisely.

<Embodiment> FIG. 1 is an overall configuration diagram of an apparatus implementing the present invention, FIG. 2 is a block configuration diagram of a control section, and FIG. 3 is a control flowchart of safe operation.

Reference numeral 1 denotes a water heater, in which low-temperature water that enters from a water inlet pipe 2 is heated by a heat exchanger 3, and the obtained hot water is discharged from a hot water outlet pipe 4. 5 is a combustion burner, and a fuel supply device 6
The required amount of fuel is supplied from Combustion air is blown from below the burner 5 by a blower fan 7. 7a is a fan motor, and 8 is a fan rotation speed detection element. The amount of fuel supplied to the burner 5 and the rotation speed of the fan 7 are controlled by a control unit 10. 9 is a remote control unit. When the hot water supply switch is pressed by the remote control unit 9 and the hot water supply temperature is set, actual hot water supply starts by opening the hot water tap. The functions of the control section 10 during hot water supply will be further explained with reference to FIG. 2. When the hot water supply temperature is set by the remote control section 11, a fuel supply amount corresponding to the hot water supply temperature is calculated in a circuit (not shown) of the control section 10, and a supply amount control command is issued to the fuel supply path 6. On the other hand, the required rotation speed No. of the fan 7 is automatically set by the fan rotation speed setting circuit 11 in accordance with the set water supply temperature. The feed feed amount required for this set rotation speed No. is calculated by the feed feed amount calculation circuit 12,
It is supplied to the motor 7a via the motor control circuit 13. The feed amount is the motor 7a.
For example, if the motor is a DC motor, the supply voltage will be high or low. On the other hand, the actual rotation speed N of the fan 7 rotated by the feed amount is detected by the fan rotation speed detection circuit 1 via the fan rotation speed detection element 8.
4, a feedback control amount is calculated in a feedback amount calculation circuit 15 based on the actual rotation speed N, and the drive amount of the motor 7a is adjusted via the motor control circuit 13. Then, whether or not the rotation of the fan 7 is abnormal is determined by comparing the actual fan rotation speed detected by the fan rotation speed detection circuit 14 and the rotation speed set by the fan rotation speed setting circuit in a determination circuit 16. If the difference in rotational speed is equal to or greater than a certain G, the rotation of the fan 7 is determined to be abnormal. If the abnormality continues for a certain period of time T or more, the determination circuit 16 sends a signal to the motor 7a via the motor control circuit 13.
The determination circuit 16 also stops the fuel supply by the fuel supply device 6 via a fuel control circuit (not shown). Further, when the combustion is stopped due to the stoppage of the air blowing and fuel supply, an abnormality notification lamp (not shown) or the like can be turned on. Similarly, the combustion control program may be reset when combustion is stopped. The difference G in rotational speed and the duration T to be determined as abnormal can be determined depending on the scale of the combustor, the size of the fan, etc.

The safe operation flow will be briefly explained along the flowchart of FIG. First, a required fan rotation speed No. is set by operating the remote control unit 9, and rotation of the fan 7 is started at the same time as combustion starts. Then, the actual fan rotation speed N is constantly detected, and when the difference G between the set rotation speed No. and the actual rotation speed N becomes a certain value or more, and this continues for a certain period of time T or more, a safety operation is activated.

<Effects> The combustor safety device of the present invention has the above-described configuration, and when the difference between the fan rotation speed that is automatically set according to the amount of fuel supplied and the actual fan rotation speed exceeds a certain level, combustion is stopped. Since the engine is stopped and safe operation is performed, the range of fan rotation abnormality changes according to changes in fan rotation speed due to changes in combustion amount, and therefore safe operation is performed according to the actual operation of the combustor. It can be done. That is, according to the present invention, it is possible to reliably detect a substantial abnormality in the blower fan, and it is possible to reliably perform safe operation of the combustor.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an apparatus implementing the present invention, FIG. 2 is a block diagram of a control section, and FIG. 3 is a control flowchart of safe operation. 1: water heater, 5: combustion burner, 6: fuel supply device, 7: ventilation fan, 7a: fan motor, 8:
Fan rotation speed detection element, 9: Remote control unit, 10:
control section.

Claims (1)

[Scope of Claims] 1. A safety device in a combustor that automatically increases or decreases the rotational speed of a blower fan in response to an increase or decrease in the amount of fuel supplied due to adjustment of the amount of combustion, which If the difference between the automatically set fan rotation speed and the actual fan rotation speed exceeds a certain level,
A safety device for a combustor, characterized in that it is configured to stop combustion and perform safe operation. 2. The safety device for a combustor according to claim 1, which stops combustion and performs a safety operation when a difference in rotational speed of a certain value or more continues for a certain period of time or more.