JPH05302711A - Device for controlling fan for combustion - Google Patents

Abstract

PURPOSE:To enable maintaining the fuel-air ratio at a specified value even if a change has occurred in the blast characteristics by a method wherein, when the deviation between the reference duty factor corresponding to a target number of revolutions and the duty factor during operation of the fan exceeds a fixed value, the target number of revolutions is corrected to an increased value. CONSTITUTION:In an operation device 11 the duty factor in post-purge after five hours' operation of a hot water-supplying device is set as a reference duty factor DS. In postpurge the number of revolutions of a fan 3 is set at a value corresponding to the maximum degree of combustion. When a target number of revolution NS is initially set for a degree of combustion I and the deviation of the actual duty factor DX in postpurge from the reference duty factor DS exceeds a proscribed value DELTAD, the target number of revolution NS is corrected to an increased value. In this manner, when a change has occurred in the blast characteristics, the fuel-air ratio can be maintained at a fixed value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan for supplying combustion air to a burner, a rotation speed setting means for setting a target rotation speed of the fan based on a combustion amount, and a rotation speed of the fan for the target rotation speed. The present invention relates to a combustion fan control device provided with a control means for controlling the conduction ratio of a DC power supply to the fan so as to match the rotation speed.

[0002]

2. Description of the Related Art The target rotational speed of a fan in a combustion fan control device as described above is set so that the air-fuel ratio can be maintained at a predetermined value when the blowing characteristics are ideal conditions in which exhaust blockage can be ignored. Was there. Then, generally, the value of the target rotation speed is not changed during operation.
By the way, when the range of the combustion amount is wide, it is more advantageous to adopt a DC fan motor. Also, connect the DC power supply and the fan drive circuit via a switch, and
The drive power of the fan can be varied by controlling the ratio of N time and OFF time (flow rate).

[0003]

In the above conventional technique, the air-fuel ratio deviates from the predetermined value when the fan performance is reduced, the air supply / exhaust passage is blocked, and the blowing characteristics are changed. As a result, the combustion characteristics may be deteriorated. An object of the present invention is to eliminate the above-mentioned conventional drawbacks and to obtain a combustion fan control device that can maintain the air-fuel ratio at a predetermined value even when the blowing characteristics change.

[0004]

In order to achieve this object, a first characteristic configuration of a combustion fan control device according to the present invention is a flow rate setting for setting a reference flow rate corresponding to the target rotational speed. Means is provided, and the rotation speed setting means corrects the target rotation speed to an increasing side as the deviation between the reference flow rate and the flow rate during operation of the fan exceeds a predetermined value. It is configured.

In a second characteristic configuration, the target rotation speed is reduced by the rotation speed setting means as the deviation between the current flow rate during operation of the fan and the reference flow rate exceeds a predetermined value. That is, it is configured to correct.

In a third characteristic configuration, an instruction means for instructing the setting of the reference flow rate is provided, and when the instruction means operates, the control means controls the rotation speed of the fan to a predetermined rotation speed. In addition, the flow rate setting means is configured to set the flow rate at that time as the reference flow rate.

In a fourth characteristic configuration, the instructing means integrates the operating time, and instructs the setting of the reference flow rate as the operating time reaches a predetermined time. That is.

[0008]

The operation of the first characteristic configuration is as follows. The reference air flow rate corresponds to the air flow rate in the ideal blowing characteristic. Therefore, when the deviation between the reference air flow rate and the air flow rate during operation of the fan exceeds a predetermined value, it can be determined that exhaust air blockage or the like occurs and the air flow characteristics deteriorate, and the air flow rate decreases. Therefore, the target rotation speed is corrected to a large value to increase the air flow rate.

On the contrary, in the second characteristic configuration, when the deviation between the flow rate during operation of the fan and the reference flow rate exceeds a predetermined value, the condition such as exhaust blockage is improved and the air flow rate is increased. You can judge that you did. Therefore, the target rotation speed is corrected to a smaller value.

The operation of the third characteristic configuration is as follows. It is considered that there are variations in the ventilation characteristics due to the installation conditions. Therefore, it is desirable to set the reference flow rate individually. Therefore, when it can be determined that the air blowing characteristics are ideal, the instruction means is activated. Since the air flow rate at that time corresponds to the air flow rate in the ideal blowing characteristics,
It can be set as the standard flow rate.

The operation of the fourth characteristic structure is as follows. Generally, when installed, it is considered to have ideal ventilation characteristics. Therefore, the predetermined time is a time that slightly exceeds the operation time in the product inspection. That is, the reference flow rate is automatically set after a while after the actual installation.

[0012]

According to the first characteristic structure, the air-fuel ratio can be maintained at a predetermined value because the air-blowing amount is controlled to increase when the air-blowing amount decreases.

Similarly, in the second characteristic configuration, since the air flow rate is controlled so as to decrease when the air flow rate increases,
The air-fuel ratio can be maintained at a predetermined value.

In the third characteristic configuration, the reference flow rate is set individually, so that the reference flow rate can be set according to the installation situation and the like.

In the fourth characteristic configuration, the reference flow rate is automatically set at the time of actual installation, so that it can be made highly convenient.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a water heater will be described below with reference to the drawings. As shown in FIG. 2, a heat exchanger 1 for heating water, a burner 2 for heating the heat exchanger 1, and a fan 3 for supplying combustion air to the burner 2.
A water heater with and is provided. The drive motor of the fan 3 is a DC motor having a permanent magnet as a field. In the figure, W1 is a water supply passage for the heat exchanger 1, and W2 is a hot water supply passage W2. The fuel gas supply passage G1 for the burner 2 is provided with two on-off valves 4 and 5 for intermittently supplying the fuel gas and an electromagnetic gas amount adjusting valve 6 for adjusting the fuel gas supply. A water amount sensor S1 that detects the amount of water supplied to the heat exchanger 1 and a water temperature sensor S2 that detects the temperature of water entering the heat exchanger 1 are interposed in the water supply passage W1. In the hot water supply passage W2,
A hot water temperature sensor S3 for detecting the hot water temperature of the heat exchanger 1 is provided. In the figure, 7 is an igniter, and 8 is a frame rod for detecting whether or not the burner 2 is ignited. And these are each connected to the controller H.

Further, a main remote controller R1 for instructing control information to the controller H and a bath remote controller R2 are provided. The main remote controller R1 is provided with an operation switch 21, a hot water supply temperature indicator 22, a hot water supply temperature setting device 23, and the like for instructing the start / stop of the operation. Bath remote control R2
The operation switch 31, the hot water supply temperature indicator 32, the additional heating switch 33, the hot water switch 34, etc. are provided.
A maintenance switch SW, which will be described later, is provided inside each of the main remote controller R1 and the bath remote controller R2.

The internal structure of the controller H will be described. As shown in FIG. 1, the calculation unit 11 that calculates the combustion amount I based on the command information from the main remote controller R1 and the bath remote controller R2 and the detection information of each sensor, the target rotation speed Ns of the fan 3 based on the combustion amount I The target rotation speed setting unit 12 as a rotation speed setting unit for setting, the DC power supply 15, the switch unit 16 for turning on / off the flow of the DC power supply 15 to the fan 3, and the rotation speed Nx of the fan 3 is the target rotation speed Ns.
, A duty ratio control unit 13 as a control means for controlling the duty ratio Dx of the DC power supply 15 to the fan 3,
Reference flow rate setting unit 14 as a flow rate setting unit that sets a reference flow rate Ds corresponding to the target rotation speed Ns, and fan 3
An encoder 17 for detecting the number of revolutions Nx and a clock 18 are provided.

The setting of the reference flow rate Ds will be described. First, the settings for normal use will be described.
The calculation unit 11 integrates the operating time Tx of the water heater.
Then, the flow rate Dx in the post-purge when the operating time Tx has passed 5 hours is set as the reference flow rate Ds. In post-purge, the rotation speed of the fan 3 is controlled to a value corresponding to the maximum combustion amount. That is, the reference flow rate Ds corresponds to the maximum combustion amount. Further, the flow rate D in the post-purge when the operating time Tx exceeds 6 hours
x is compared with the previously set reference flow rate Ds, and the larger one is set as the reference flow rate Ds. That is, the rotation speed corresponding to the maximum combustion amount corresponds to the predetermined rotation speed.

Next, setting in the maintenance mode will be described. The maintenance mode is activated when the fan 3 or the like is replaced after installation, and is activated by turning on maintenance switches provided in the main remote controller R1 and the bath remote controller R2. Even in the maintenance mode, the rotation speed of the fan 3 is controlled to a value corresponding to the maximum combustion amount. Then, the flow rate Dx at that time is set as the reference flow rate Ds. That is, the calculation unit 11 and the maintenance switch SW correspond to the instruction means.

The setting of the target rotational speed Ns of the fan 3 will be described with reference to FIG. As shown by the solid line in FIG. 6, it is assumed that the target rotation speed Ns for the combustion amount I is initialized. In the post-purge, the flow rate Dx at that time is compared with the reference flow rate Ds. Here, as the deviation between the reference flow rate Ds and the flow rate Dx exceeds the predetermined value ΔD, the target rotation speed Ns is corrected to the increasing side. On the other hand, conversely, the target rotational speed Ns is corrected to the decreasing side as the deviation between the above-mentioned flow rate Dx and the reference flow rate Ds exceeds the predetermined value ΔD. For example, when correcting the target rotation speed Ns to increase,
The target rotation speed Ns for the maximum combustion amount is increased by a predetermined value ΔN. The target rotation speed Ns for the minimum combustion amount is set to a predetermined value ΔN.
Is multiplied by a constant Ka less than 1. Then, connect these two points with a straight line. That is, the dotted line in FIG. 6 indicates the corrected target rotation speed Ns. It should be noted that, on both the increasing side and the decreasing side, when the number of corrections reaches a predetermined number K, it is judged as abnormal and the abnormality processing is performed.

Next, the operation of the controller H will be described with reference to the flow charts shown in FIGS. First, it is determined whether or not hot water supply is required, and if hot water supply is not required, then it is determined whether or not hot water supply is currently being performed. If the hot water is not being supplied until now, it returns as it is. If hot water is being supplied up to the present time, the process returns after executing the fire extinguishing process and the post purge. When it is determined that the hot water supply is required, it is determined whether or not the ignition is being performed, and the ignition process for igniting the burner 2 is executed only when the ignition is not being performed. Then, the combustion state of the burner 2 is controlled.

The post purge will be described. In the post-purge, the fan 3 is basically operated at the target rotation speed Ns for the maximum combustion amount for a predetermined time. Here, the reference flow rate Ds is set in the first post-purge when the operating time Tx has passed 5 hours. Further, the flow rate Dx in the first post-purge when the operating time Tx has passed 6 hours is compared with the previously set reference flow rate Ds, and the larger one is set as the reference flow rate Ds. When the reference flow rate Ds is set, the flow rate Dx in the post-purge and the reference flow rate Ds are set for each post-purge.
Are compared, and as the deviation between the two exceeds a predetermined value ΔD,
The target rotation speed Ns is corrected as described above. Further, on both the increasing side and the decreasing side, when the number of corrections reaches a predetermined number K, it is judged as abnormal and the abnormality processing is performed.

[Other Embodiments] In the above embodiment, the rotation speed of the fan 3 is detected by using the encoder, but the rotation speed of the fan 3 may be detected by the counter electromotive voltage of the DC motor.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a block diagram of a controller

FIG. 2 is a block diagram of the overall configuration

FIG. 3 is a flowchart of control operation.

FIG. 4 is a flowchart of control operation.

FIG. 5 is a flowchart of control operation.

FIG. 6 is an explanatory diagram of setting a target rotation speed.

[Explanation of symbols]

 2 burner 3 fan 11 or SW instruction means 12 rotation speed setting means 13 control means 14 conduction ratio setting means 15 DC power supply Ds reference conduction ratio Dx conduction ratio Ns target rotation speed Tx operating time

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshikazu Sanbe 1-52-1 Oka, Minami-shi, Minato-ku, Osaka-shi, Osaka, Harman Co., Ltd. (72) Inventor ▲ Yoshi ▼ Kozo Yama, 1 Minami-ichioka, Minato-ku, Osaka-shi, Osaka No. 1-52 Harman Co., Ltd. (72) Inventor Munehisa Sawada 1-chome 1-52 Minami-shi, Minato-ku, Osaka-shi, Osaka Prefecture 1-52 Harman Co., Ltd. (72) Kenji Aoki 1-chome, Minami-shi, Osaka-shi, Osaka 1-chome Number 52 Harman Co., Ltd. (72) Inventor Shinichi Uraya 1-1-1 Minami-shi Oka, Minato-ku, Osaka, Osaka Prefecture No. 52 Harman Co., Ltd. (72) Keiji Kikuno 1-1-chome Minami-shi Oka, Minato-ku, Osaka Prefecture Osaka No.52 Harman Co., Ltd.

Claims (4)

[Claims] 1. A fan (3) for supplying combustion air to a burner (2), and a rotation speed setting means (12) for setting a target rotation speed (Ns) of said fan (3) based on a combustion amount.
And the rotation speed of the fan (3) is equal to the target rotation speed (N
control means (1) for controlling the conduction ratio (Dx) of the DC power supply (15) to the fan (3) so as to coincide with (s).
3) is provided for the combustion fan control device, the reference flow rate (Ds) corresponding to the target rotation speed (Ns).
And a rotation speed setting means (12) for setting the reference flow rate (Ds) and the current flow rate (Dx) during operation of the fan (3). The combustion fan control device is configured to correct the target rotation speed (Ns) to the increasing side when the deviation of the above exceeds a predetermined value. 2. As the deviation between the current flow rate (Dx) during operation of the fan (3) and the reference current flow rate (Ds) exceeds a predetermined value by the rotation speed setting means (12). The combustion fan control device according to claim 1, wherein the target rotation speed (Ns) is configured to be corrected to a decreasing side. 3. An instruction means (11 or SW) for instructing setting of the reference flow rate (Ds) is provided, and when the instruction means (11 or SW) operates, the control means (1)
3) controls the rotation speed of the fan (3) to a predetermined rotation speed, and the flow rate setting means (14) sets the flow rate (Dx) at that time to the reference flow rate (Ds). 3. The combustion fan control device according to claim 1, wherein the combustion fan control device is configured as follows. 4. The operating time (T
x) is integrated, and is configured to instruct the setting of the reference flow rate (Ds) when the operating time (Tx) reaches a predetermined time. Fan controller.