JP3513213B2 - Combustion fan control 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 fan for ventilating combustion air through a burner, a rotation speed setting means for setting a target rotation speed of the fan based on a combustion amount of the burner, and a rotation speed of the fan. And a control means for controlling the driving electric power value supplied to the fan so that is equal to the target rotational speed.

[0002]

2. Description of the Related Art In the above combustion fan control device, when there is an influence from the outside on the ventilation operation of the fan, for example, there is an outside wind, the ventilation path is clogged with dust, or the blades of the fan. In the case where dust accumulates on the fan, the actual air flow rate of the fan is different from the preset air flow rate only by maintaining the fan rotation speed at the target rotation speed. Therefore, conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2-57817, a configuration in which the driving power for the fan, that is, the applied voltage or current value to the fan is controlled so as not to fall below a set value was there. In the above-mentioned conventional configuration, even if the fan rotation speed is maintained at the target rotation speed, when the actual air volume is less than the set volume, the work of the fan decreases, so the driving power becomes a small value. Focusing on the point, while monitoring the power for driving, the influence from the outside as described above is eliminated as much as possible, and it is possible to maintain an appropriate air volume.

[0003]

However, the above conventional structure still has the following points to be improved.
That is, of the various influences from the outside on the ventilation operation of the fan as described above, when dust is accumulated on the blades of the fan, the amount of air flow when the rotation speed of the fan is maintained at the target rotation speed is Since the change and the change in the driving power for the fan have a substantially proportional relationship, it is possible to maintain the target air volume by controlling the driving power so as not to fall below the set value. However, when there is wind from the outside, when the ventilation path is clogged with dust, or the like, the change in the driving power with respect to the change in the air volume is unlikely to appear. Hereinafter, this point will be described in detail.

The work amount W _M of the electric drive section (for example, an electric motor) in the fan is given by the following equation.

[0005]

## EQU1 ## W _M = KIV where K is a predetermined coefficient, I is a current value, and V is an applied voltage value.

On the other hand, a fan blower (for example,
The work amount W _F of the blade portion is given by the following equation.

[0007]

[Expression 2] W _F = ρ · P · Q where ρ is air density, P is pressure, and Q is air volume.

Here, ignoring the drive efficiency of the fan,
The work W _M of the electric drive unit and the work W _{F of the} blower unit match. Therefore,

[0009]

[Equation 3] K ・ I ・ V = ρ ・ P ・ Q

In the above conventional configuration, the change state of the air volume Q is monitored based on the change of the current I or the voltage V, but when the pressure P changes with the air volume change. Changes in the air flow cannot be detected only by the change in the current I or the voltage V.

The present invention has been made by paying attention to the above points, and an object thereof is to provide a combustion fan control device capable of maintaining a fan air volume at a target volume as much as possible. There is a point to do.

[0012]

The features of the first invention are as follows:
A fan that ventilates combustion air to the burner, a rotation speed setting unit that sets a target rotation speed of the fan based on a combustion amount of the burner, and a rotation speed of the fan match the target rotation speed, In a combustion fan control device provided with a control means for controlling a driving electric power value supplied to the fan, a pressure detection means for detecting a pressure in a ventilation path through which the combustion air is ventilated by the fan. It is provided, the rotation speed setting means, the power value,
Based on the pressure detected by the pressure detection means, in order to bring the amount of combustion air ventilated to the burner close to an appropriate amount,
It is configured to correct the target speed ,
A reference power value setting means for setting a corresponding reference power value,
Reference pressure setting for setting the reference pressure corresponding to the reference state
And a rotation speed setting means,
When the deviation between the value and the reference power value exceeds the set value
The deviation between the detected pressure and the reference pressure is set.
If it exceeds the value, set the correction amount of the target speed to a large value.
However, the deviation between the detected pressure and the reference pressure is below the set value.
If it is turning, the correction amount of the target speed is set to a small value.
It is configured as follows.

[0013]

A characteristic configuration of the second invention is to specify a configuration suitable for carrying out the first invention, and an instruction means for instructing setting of the reference power value and the reference pressure is provided,
When the instruction means is activated, the control means controls the rotation speed of the fan to a predetermined rotation speed, and the reference power value setting means controls the power value at that time and the detection value of the pressure detection means. Each of them is configured to be set as the reference power value and the reference pressure.

A characteristic configuration of the third invention is to specify a configuration suitable for carrying out the second invention, and the instructing means is
The operating time is integrated, and when the integrated time reaches a set time, the setting of the reference power value and the reference pressure is instructed.

The characteristic configuration of the fourth invention is the first, second or
3 A configuration suitable for carrying out the invention is specified, wherein the fan is configured to be driven by a DC power source, and the control means changes the conduction ratio of the power source to the fan to change the power consumption. It is configured to control the value.

[0017]

According to the characteristic construction of the first aspect of the invention, the power value for driving the fan is controlled so that the rotation speed of the fan matches the target rotation speed, and proper combustion air is ventilated to the burner. . When the ventilation path is blocked by dust or the like, the combustion air for the burner is caused even if the fan rotation speed is maintained at the target rotation speed. And the pressure in the ventilation path changes.

Therefore, a value that changes with a change in the amount of ventilation, that is, the electric power value, which is a parameter in the function of the work of the fan, and the pressure in the ventilation passage are detected, and this electric power value is detected. Based on the detected pressure, the target rotational speed is corrected so that the amount of combustion air ventilated by the burner approaches an appropriate amount.

Further , according to the characterizing feature of the first invention, for example, in a reference state such as an initial installation state, that is, in a state where various external influences on the ventilation operation of the fan such as blockage of the ventilation path do not occur. , The reference power value and the reference pressure are set in advance. When the deviation between the reference power value and the power value controlled so that the fan rotation speed is maintained at the target rotation speed exceeds the set value and becomes large, the above-mentioned external It is considered that the air volume is changing due to the influence, but at this time, if the deviation between the detected pressure detected by the pressure detecting means and the reference pressure exceeds the set value, the air volume is compared with the deviation of the electric power value. Since it is considered that the change is large, it is possible to obtain an appropriate air volume by increasing the correction amount of the target rotation speed.

Further, if the deviation between the detected pressure and the reference pressure is less than the set value, it is considered that the pressure change is small with respect to the deviation of the electric power value. You can

According to the characterizing structure of the second invention, the following function is obtained in addition to the function of the characterizing structure of the first invention. By operating the indicating means in a state suitable as the reference state, the reference power value and the reference pressure are set, so that the reference power value and the reference power value are set regardless of the installation status of the device or the variation in characteristics between products. The reference pressure can be set as an appropriate value.

According to the characterizing structure of the third invention, the following function is obtained in addition to the function of the characterizing structure of the second invention. At the beginning of installation of the device, it is considered to be in the reference state, so by setting the set time to, for example, an accumulated time slightly exceeding the operation time in product inspection,
The setting of the reference electric power value and the reference pressure is automatically performed as the accumulated operating time reaches the set time after a short time has passed since the installation.

According to the characteristic configuration of the fourth invention, the first and second
Alternatively, the following operation is provided in addition to the operation according to the characteristic configuration of the third invention. Since the fan is driven by the DC power supply, compared to the case of being driven by the AC power supply, the responsiveness is excellent when the target rotation speed is changed, and it is possible to reduce the time delay to an appropriate air volume, Since the configuration is such that the duty factor of the DC power supply is changed, the control configuration is simpler than when controlling the power of the AC power supply.

[0024]

According to the characterizing feature of the first invention, it is possible to always allow the burner to ventilate an appropriate amount of combustion air, regardless of the external influence on the ventilation operation of the fan. It has become possible to provide a combustion fan control device capable of maintaining an optimum air-fuel ratio.

Further , according to the characteristic configuration of the first aspect of the invention , the target rotation speed is corrected on the basis of the deviation of the driving power value of the fan to be controlled from the reference state, thereby changing the ventilation state ( The amount of correction of the target rotation speed with and without pressure change is based on the deviation of the detected pressure in the ventilation path from the reference state. The target rotation speed can be corrected so as to be in an appropriate state with respect to the difference in the factor of the influence from the outside on the ventilation operation of the fan by changing the above.

According to the characterizing feature of the second invention, the following effect is obtained in addition to the effect of the characterizing feature of the first invention. Regardless of the installation status of the equipment and variations in characteristics between products, the reference power value and reference pressure are set as appropriate values, so that the target rotation speed is always corrected in an appropriate state. .

According to the characterizing structure of the third invention, the following effect is obtained in addition to the effect of the characterizing structure of the second invention. Since the setting of the reference power value and the reference pressure is performed automatically in the proper state as the reference state and automatically, there is no forgetting to set compared to the case of artificial setting, and practical convenience It can be expensive.

According to the characteristic configuration of the fourth invention, the first and second
Alternatively , there are the following effects in addition to the effects of the characteristic configuration of the third invention. The rotation speed of the fan can be controlled with a simple control configuration and with a small response delay.

[0029]

Embodiments will be described below with reference to the drawings. Figure 2
FIG. 1 shows a water heater having a combustion fan control device according to the present invention. This water heater has a heat exchanger 1 for heating water,
The heat exchanger 1 is provided with a burner 2 that heats the heat exchanger 1, a fan 3 that supplies combustion air to the burner 2, and the like, and the heat exchanger 1 is provided with a water supply passage W1 through which water is supplied and is heated. A hot water supply passage W2 for supplying hot water to a hot water tap (not shown) is connected. The water supply path W1 is provided with a water temperature sensor S2 for detecting the temperature of water entering the heat exchanger 1, and a water quantity sensor S1 for detecting the quantity of water supplied to the heat exchanger 1. A hot water temperature sensor S3 for detecting the hot water temperature of the exchanger 1 is provided. The combustion exhaust gas of the burner 2 is exhaust gas 40
It is designed to be discharged through the room.

Fuel gas supply path G1 to the burner 2
Is provided with two open / close valves 4 and 5 for intermittently supplying the fuel gas and an electromagnetic gas amount adjusting valve 6 for adjusting the fuel gas supply amount, and an igniter 7 for ignition is provided near the burner 2.
And a frame rod 8 for detecting whether or not the burner 2 is ignited.

Further, there are provided a controller H for executing combustion control of the burner 2 and rotation speed control of the fan 3, and a main remote controller R1 and a shower remote controller R2 for issuing control information to the controller H. The main remote controller R1 has an operation switch 2 for instructing start / stop of operation.
1, a hot water supply temperature display 22, a hot water supply temperature setting device 23 and the like are provided. The shower remote controller R2 includes an operation switch 31, a hot water supply temperature display unit 32, a hot water supply temperature setting device 33, and the like. Further, a maintenance switch SW described later is provided inside each of the main remote controller R1 and the shower remote controller R2.

The controller H causes the igniter 7 to ignite the burner 2 when the detected value of the water amount sensor S1 exceeds the set value due to the opening operation of the hot water tap, and the water amount sensor S1.
The combustion amount of the burner 2, that is, the gas amount adjusting valve 6 is controlled on the basis of the amount of supplied water and the detected value of the incoming water temperature sensor S2, and the detected value of the hot water temperature sensor S3 matches the set hot water supply temperature. First, the combustion control of the burner 2 is executed so as to correct the combustion amount.

Further, the controller H is configured to control the rotation speed of the fan 3 so that the ventilation amount of the combustion air by the fan 3 with respect to the burner 2 is in a proper state with respect to the combustion amount of the burner 2. ing. The electric motor for driving the fan 3 is a DC motor having a permanent magnet as a field. Inside the combustion chamber of the burner 2 is provided a pressure sensor S4 for detecting the pressure inside the combustion chamber, which is a ventilation passage for the combustion air by the fan 3, and the detection information of this pressure sensor S4 is also input to the controller H. Is configured to. FIG. 1 shows a fan rotation speed control configuration in the controller H. A computing unit 11 for computing the combustion amount of the burner 2 based on the command information from the main remote controller R1 and the shower remote controller R2 and the detection information from the sensors.
Set the target rotational speed N _S of the fan 3 based on the combustion amount
The target rotation speed setting unit 12 as the rotation speed setting means , the DC power supply 15, and the flow of the DC power supply 15 to the fan 3 are turned on.
The DC power supply 15 for the fan 3 is set so that the rotation speeds of the switch unit 16 and the fan 3 that are turned off match the target rotation speed.
Of the current flow rate D _X (an example of a power value for driving) as a control unit, and a reference flow rate D _S (an example of a reference power value) corresponding to the reference state is set. Reference flow rate controller 14 as reference power value setting means, reference pressure setting portion 19 as reference pressure setting means for setting reference pressure P _S corresponding to the reference state, encoder for detecting rotation speed N _X of fan 3. A clock 17 and a clock 18 are provided respectively.

The setting of the reference flow rate D _S and the reference pressure P _{S in the} normal use state and the maintenance mode respectively.
The setting of will be described. First, the settings for normal use will be described. The calculation unit 11 integrates the operating time of the water heater. Then, the operating time T _X is such that the operating time slightly exceeds the operating time in the product inspection, that is,
The flow rate D _X in the post-purge (the ventilation operation performed after the combustion of the burner 2 is stopped) after 5 hours is set as the reference flow rate D _S , and the detected pressure P _{X at} that time is set.
Is set as the reference pressure P _S. 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 D _S corresponds to the maximum combustion amount. Further, the flow rate D _X in post-purge when the operating time has passed 6 hours is compared with the previously set reference flow rate D _S, and the larger one is set as the reference flow rate D _S. 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 the water heater is installed, and is activated by turning on a maintenance switch SW provided on the main remote controller R1 and the shower 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. And
The flow rate D _X and the detected pressure P _{X at} that time are set as the reference flow rate D _S and the reference pressure P _S , respectively. Therefore, the calculation unit 11 and the maintenance switch SW correspond to the instructing means.

The setting of the target rotation speed of the fan 3 will be described.
To do. When the post-purge is executed
Flow rate D_XAnd standard flow rate D_STo compare. Where
Flow rate D_XIs the standard flow rate D_SGreater than, and
If those deviations exceed the set value ΔD, the target rotation
Number N_SIs corrected to the increasing side, and the flow rate D_XIs the standard flow rate
D_SOn the smaller side, and their deviation is the set value
If ΔD is exceeded, the target speed N_SIs corrected to decrease side
To do. Further, the pressure P detected by the pressure sensor S4 _XAnd before
Reference pressure P_SIf the deviation from and exceeds the set value ΔP,
The target speed N_SSet a large correction amount for the
If the deviation between the force and the reference pressure is below the set value,
The target speed N_SSet the correction amount of to small.

Description will be made with reference to FIG. Shown in solid line in Figure 6
As shown in FIG._SInitial setting
It is supposed to be. Here, the flow rate D as described above_X
And standard flow rate D_SBased on comparison with_S
Is corrected to the increasing side with the correction amount set to small.
In this case, the target speed N for the maximum combustion amount_SIncrease by a predetermined value
Point and target speed N for minimum combustion amount_SPredetermined
And a point that is increased by a value less than 1
The straight line is the corrected target rotation speed N on the increasing side of the first stage. _STona
It Such a flow rate D_XAnd standard flow rate D_SComparison with
It is carried out for each post-purge, and it is necessary to correct it on the increasing side.
In this case, the correction target rotation speed N of the first stage_S(C +
Further increase from 1) in increments similar to the above increments.
Corrected target rotation speed N in multiple stages_SGradually increasing complement to (C + n)
To correct. Then, the number of corrections on the increasing side reaches the set number K.
Then, it is judged that it is abnormal and the abnormal process is performed.
ing. In addition, the correction of the decrease side is the same as the target of the initial setting.
Number of revolutions N_SFrom the first stage on the decreasing side
Correction target speed N_SGradual decrease from (C-1) to multiple levels
Make a small correction and the number of corrections on the decreasing side reaches the set number K
Then, it is judged that it is abnormal, and abnormality processing is started.
There is.

Further, when the deviation between the detected pressure P _X and the reference pressure P _S exceeds the set value ΔP and the correction amount of the target rotation speed N _S is set to a large value, the above-described correction target of a plurality of stages is used. The rotation speed N _S is corrected to increase or decrease every two steps. That is, the correction amount that is twice as large as the correction amount when the correction amount is set small is set.

Next, the operation of the controller H will be described with reference to the flow charts shown in FIGS. Figure 3
As shown in, first, it is determined whether or not hot water supply is necessary. If hot water supply is not necessary, it is determined whether or not hot water is being supplied until now.
If the hot water is not being supplied until now, the process directly returns (steps 1 and 2). Also, if the hot water is currently being supplied,
After executing the fire extinguishing process and the post-purge control, the process returns (steps 3 and 4). When it is determined that hot water supply is required, it is determined whether or not ignition is being performed. Only when ignition is not being performed, the ignition process for igniting the burner 2 is executed, and the combustion state of the burner 2 is appropriate. The combustion state is controlled (steps 5-8).

The post-purge control will be described.
As shown in FIGS. 4 and 5, in the post-purge, the fan 3 is basically operated at the target rotation speed N _S for the maximum combustion amount for a predetermined time (step 9). Here, the reference flow rate D _S and the reference pressure P _S in the first post-purge when the operating time T _X has passed 5 hours are set (steps 10 to 14). Further, in the first post-purge when the operating time T _X has passed 6 hours, the flow rate D _X is compared with the previously set reference flow rate D _S, and the larger one is the reference flow rate. Set as D _S (step 15)
~ 19). Further, the detected pressure P _X is compared with the previously set reference pressure P _S, and the larger one is set as the reference pressure P _S (steps 21 and 21). Then, each time the post-purge is executed, the flow rate D _X in the post-purge is compared with the reference flow rate D _S, and the detected pressure P _X is compared with the reference pressure P _S. When the flow rate D _X is smaller than the reference flow rate D _S and the deviation thereof exceeds the predetermined value ΔD, the target rotational speed N _S is corrected to the increasing side, and the flow rate D _X is the reference flow rate. If it is larger than the rate D _S and the deviation thereof exceeds the predetermined value ΔD, the target rotation speed N _S is corrected to the decreasing side. At this time, the deviation between the detected pressure P _X and the reference pressure P _S is a predetermined value ΔP.
If it is smaller, the correction is made in one step, and if the deviation exceeds the predetermined value ΔP, the correction is made in two steps (steps 22 to 31).

In both the increasing side correction and the decreasing side correction, when the number of corrections reaches the predetermined number K, it is judged as abnormal and abnormal processing is performed (steps 32 and 33).
Then, the fan 3 is stopped when the required predetermined time for post-purging has elapsed (steps 34 and 35).

[Other Embodiments] (1) In the above embodiment, the pressure sensor S4 is configured to detect the pressure inside the combustion chamber, but it may be configured to detect the pressure inside the exhaust passage 40. well, also may be used a pressure sensor of the differential pressure detection type for measuring the pressure difference between inlet and outlet of the fan 3, further it is used a pressure sensor for measuring the intake pressure of the intake port of the fan 3 Good.

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

(2) In the above embodiment, the drive motor for the fan 3 is a DC motor, but the drive motor is not limited to this, and may be driven by an AC motor. The configuration is not limited to the above control, and the drive voltage may be controlled or the drive current may be controlled. ( 3 ) In the above embodiment, the rotation speed of the fan 3 is detected by the encoder 17, 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 although reference numerals are given in the claims to facilitate the comparison with the drawings, 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] Overall configuration of a water heater

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 view of setting a target rotation speed.

[Explanation of symbols]

2 burner 3 fan 11 instruction means 12 rotation speed setting means 13 control means 14 reference power value setting means 19 reference pressure setting means D _X power value D _S reference power value ΔD setting value N _S target rotation speed P _X detection pressure P _S reference Pressure ΔP Set value S4 Pressure detecting means SW Instructing means T _X Accumulated time

   ─────────────────────────────────────────────────── ─── Continued front page       (56) Reference JP-A-5-302711 (JP, A)                 JP 63-194122 (JP, A)                 JP-A-2-57817 (JP, A)

Claims (4)

(57) [Claims] 1. A fan (3) for ventilating combustion air to a burner (2), and a rotation speed setting means for setting a target rotation speed of said fan (3) based on the combustion amount of said burner (2). 12) and a control means (1) for controlling the drive power value (D _X ) supplied to the fan (3) so that the rotation speed of the fan (3) matches the target rotation speed.
3) provided with a pressure detecting means (S) for detecting a pressure (P _X ) in a ventilation path through which the combustion air is ventilated by the fan (3).
4) is provided, and the rotation speed setting means (12) controls the burner (2) based on the electric power value (D _X ) and the pressure (P _X ) detected by the pressure detection means (S4). A standard configured to correct the target rotational speed (N _S ) so as to bring the amount of ventilation air for combustion close to an appropriate amount, and set a reference power value (D _S ) corresponding to the reference state.
Power value setting means (14) and a base corresponding to the reference state
With a reference pressure setting means (19) for setting the quasi pressure (P _S ).
The rotation speed setting means (12) is provided with a deviation between the electric power value (D _X ) and the reference electric power value (D _S ).
Deviation exceeds the set value (ΔD), the deviation between the detected pressure (P _X ) and the reference pressure (P _S )
If the value exceeds the set value (ΔP), the target speed (N
_S ) is set to a large correction amount, and the deviation between the detected pressure (P _X ) and the reference pressure (P _S ) is
If it is below the set value (ΔP), the target speed (N
Combustion fan control device that is configured to set a small correction amount for _S ) . Wherein said reference power value (D _S) and the reference pressure
Force instruction means for instructing the setting of _{(P S) (11, SW} ) is
When the instruction means (11, SW) is provided, the control is performed.
A means (13) rotates the number of rotations of the fan (3) by a predetermined number.
Number, and the reference power value setting means (14)
Is the electric power value (D _X ) at that time and the pressure detecting means
Each of the pressures (P _X ) detected by (S4) is set to the reference power.
Set the value (D _S ) and the reference pressure (P _S )
The combustion fan control device according to claim 1, wherein the combustion fan control device is configured as follows . 3. The instructing means (11) integrates the operating time, and the integrated time (T _X ) is equal to a set time.
As it reaches, the reference power value (D _S ) and the reference
請configured to indicate the setting of the pressure (P _S)
The combustion fan control device Motomeko 2 wherein. 4. The fan (3) is driven by a DC power source.
The control means (13) is configured to
Change the current flow rate of the power source to the fan (3)
The method of claim 1, wherein the value (D _X ) is controlled .
The combustion fan control device according to 2 or 3.