JP2578031Y2 - Fan speed control device for gas combustion equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention is driven by an AC motor for supplying combustion air to a combustion chamber in a gas combustion device.
The present invention relates to a rotational speed control device for a fan to be used .

[0002]

2. Description of the Related Art Some recent gas-burning devices such as instantaneous water heaters are designed to maintain an air-fuel ratio within a predetermined range by changing a rotation speed of an electric fan in accordance with a gas supply amount. There are a DC fan and an AC fan used for this, and the AC fan is cheaper in terms of cost. Exchange
In the flow type, rotation speed control is performed by phase control or voltage control.
Some do it. In such prior art, as shown in FIG. 6, the main control means 1 controls a gas supply amount according to a control input such as a detected temperature of hot water or a set temperature, and
Fan driven by AC motor (hereinafter called AC fan)
The rotation speed of the AC fan 25 is set by comparing the set rotation speed with the actual rotation speed of the AC fan 25, and the control amount for controlling the rotation speed of the AC fan 25 is determined by the control amount calculating means 2. In some cases, the AC fan 25 is driven by the fan drive means 3 on the basis of this control amount to supply combustion air according to the gas supply amount.

[0003]

In the case of the phase control, as shown in FIG. 7, the voltage applied to the AC fan is turned on in the middle of each half cycle in synchronization with the AC voltage waveform, and the ignition angle α shown in the figure. (Control amount) is changed to change the rotation speed of the AC fan. However, as shown by a curve D in FIG. 4, the change characteristic of the rotation speed of the AC fan with respect to the firing angle α indicates that the firing angle α is large in the range where the firing angle α is large (that is, near the maximum rotation speed of the AC fan). The rate of change of the rotation speed of the AC fan with respect to the rate of change is reduced. Therefore, in such a range, even if the ignition angle α is changed by the control device, the rotation speed of the AC fan does not change immediately and the response becomes slow, and the characteristics of the gas combustion equipment such as the air-fuel ratio and the hot water temperature characteristics are reduced. There is a problem of lowering. A similar problem exists in the case of controlling the rotation speed of an AC fan by voltage control.

In order to avoid such a problem, the AC fan is operated in a range lower than the maximum rotation speed of the AC fan in a normal use state, and is not operated in a large range where the firing angle α is around 180 degrees. It is also considered. However, in this type of gas-fired equipment, if the exhaust resistance increases due to the extension of the exhaust passage or the exhaust blockage, the rotational speed may increase and operate near the maximum rotational speed. It cannot be solved.

The present invention solves such a problem and reduces the characteristics of a gas-fired apparatus by responding promptly to a control amount such as a firing angle that is input even when operating near the maximum rotational speed. It is an object of the present invention to obtain a rotation speed control device for an AC fan that does not cause the rotation.

[0006]

To SUMMARY OF THE INVENTION Therefore, rotation speed control device of the fan that put the gas combustion apparatus according to the present invention is,
As shown in FIG. 1, a fan 25 that to supply driven combustion air in an AC motor, the detected temperature and set before notated § down 25 controls the gas supply amount according to the control input such as temperature
Rotation and main control means 1 for setting the speed, prior to comparing the actual rotational speed of the front notated § emission 25 that is set in
And a control amount calculation means 2 calculates the control amount for controlling the rotational speed of the notated § down 25, a fan driving means 3 for driving the notated § <br/> down 25 before based on the control amount in the rotation speed control device of the fan that put to become gas-fired equipment, the control amount calculated by the control amount calculation means 2 is the rate of change in range the control quantity is larger than the change rate in the range the control quantity is small also a control quantity conversion unit 4 for converting the correction control amount such that a large, the fan driving unit 3 is characterized in that to drive the notated § emission 25 before on the basis of the correction control amount.

[0007]

The main control means 1 controls the gas supply amount in accordance with the control input such as the detected temperature and the set temperature and drives the gas by an AC motor.
Set the rotational speed of the fan 25 to be moving, the control amount calculation means 2 controls the rotational speed of the fan 25 by comparing the actual rotational speed detected from the rotational speed and the fan 25 that is the set Is calculated to perform the control. The control amount conversion means 4 converts the control amount into a correction control amount such that the rate of change in a range where the control amount is large is larger than the rate of change in a range where the control amount is small. driving the notated § emission 25 before on the basis of the correction control amount. Fan 25
Correction control amount for driving the, since the range control amount is large rate of change is converted so as to be larger, trough tofu § rate of change of rotational speed is smaller than the maximum rotational speed around the control amount is large The characteristics of the motor 25 are canceled out, and the control amount calculated by the control amount calculating means 2 is close to the maximum rotational speed where the control amount is large.
The rotation speed of the fan 25 rapidly changes according to the change in the controlled variable.

[0008]

As described above, according to the present invention, even if the control amount is large in the range near the maximum rotational speed, the control amount calculating means 2 can be used.
Since the rotational speed of the fan 25 in accordance with a change in the control amount of the operation changes quickly by the response becomes faster, it is not possible to lower the characteristics of the gas burning appliance.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. As shown in FIG. 2, a gas burner 20 is provided at a lower portion in a case 10 forming a combustion chamber of an instantaneous water heater, and a main solenoid valve 2 arranged in series from a gas supply side.
2. Fuel gas is supplied by a gas supply path 21 having a proportional solenoid valve 24 and a main solenoid valve 23, and combustion air is supplied by an AC fan 25 provided below the case 10. The source solenoid valve 22 and the main solenoid valve 23 are solenoid valves that perform only opening and closing, and the proportional solenoid valve 24 changes its opening continuously in accordance with the applied control current to reduce the amount of gas supplied to the gas burner 20. To change it. AC fan 2
Reference numeral 5 indicates that the rotation speed is continuously changed by the phase control, and an amount of combustion air is supplied according to the gas supply amount so that the air-fuel ratio is maintained within a predetermined range.

A water flow sensor 38 is provided on a water supply pipe 16 connected to the inlet side of a fin tube type heat exchanger 15 provided in the case 10 above the gas burner 20, and a hot water supply pipe 17 connected to the outlet side is provided. Hot water temperature sensor 39 and hot water tap 1
8 are provided. The feed water from the feed pipe 16 is heated by the gas burner 20 when passing through the heat exchanger 15,
Hot water is supplied from hot water tap 18 at a predetermined temperature. The upper part of the case 10 above the heat exchanger 15 is connected to the exhaust stack 12 through the hood 11, and an ignition lock for igniting the gas burner 20 is provided in the case 10 immediately above the gas burner 20.
The door 37 is provided.

As shown in FIG. 2, the electronic control unit 30 comprises:
Central processing unit (CP) that controls the operation of the instantaneous water heater
U) 31, a read-only memory (ROM) 32, a writable memory (RAM) 33, and interfaces 34 and 35 for exchanging data between the CPU 31 and the outside. The interface 34 has a valve drive circuit 26
, An AC fan 25 via a fan drive circuit 29, an ignition plug 37 via an ignition circuit 40, and a water flow sensor 38 and a hot water temperature sensor 39. ing. A remote control box 36 provided with various switches, a water temperature setting device, various display lamps, and the like necessary for the operation of the instantaneous water heater is connected to the CPU 31 via an interface 35. The ROM 32 has a control program for controlling the operation of the instantaneous water heater, a program for setting the rotation speed of the AC fan 25,
And a control program for controlling the rotation speed of the RAM.
3 stores a tapping temperature, various detected values, and the like.

In the comparison between the present embodiment and the claims, CP
A part of U31 controls the main control means 1 and the control amount
A part of the PU 31 and the ROM 32 and the RAM 33 constitute the control amount calculating means 2, and the fan drive circuit 29 constitutes the fan drive means 3.

Next, the operation of the above embodiment will be described. When the hot water tap 18 is opened while the power of the electronic control unit 30 is turned on and the water flow through the water supply pipe 16 is detected by the water flow sensor 38, the CPU 31 opens the original electromagnetic valve 22 and the main electromagnetic valve 23 and the proportional electromagnetic valve 24. Is a predetermined ignition opening, and the AC fan 25 is operated at a predetermined ignition rotation speed. Further, the ignition circuit 40 is operated, and the ignition plug 37 is used to operate the gas burner 20.
Ignition of the gas spouted from the water starts the operation of the instant water heater. During the operation of the instantaneous water heater, the CPU 31 uses the hot water temperature detected by the hot water temperature sensor 39 to control the remote control box 36.
By comparing the input temperature with the set temperature, a solenoid valve current for adjusting the tap water temperature to the set temperature is calculated and applied to the proportional solenoid valve 24 to control the gas supply amount to the gas burner 20. At the same time, the CPU 31 sets the rotation speed of the AC fan 25 so as to obtain a predetermined air-fuel ratio based on the control program in the ROM 32, and thereby controls the rotation speed of the AC fan 25.

FIG. 3 shows a flowchart of a program for controlling the rotation speed of the AC fan 25. C
First, in step S10, the PU 31 inputs the actual rotation speed of the AC fan 25 detected by the rotation speed detector (not shown), and in step S11, sets this in relation to the solenoid valve current of the proportional solenoid valve 24. The ignition angle α to be given to the AC fan 25 is calculated by PID feedback control calculation in comparison with the rotation speed thus calculated. In the following step S12, the CPU 31 compares the firing angle α with a predetermined value B. As shown in FIG. 5, the predetermined value B is about 172 degrees (96% in the case of a control amount with 180 degrees being 100%) in the present embodiment.

If α <B, the CPU 31 advances the control operation to step S13 to calculate the correction firing angle β using the correction formula A1, and if α <B, the CPU 31 advances the control operation to step S14 and advances the control operation to step S14. A2 is used to calculate the correction firing angle β. As shown in FIG. 5, when the firing angle α is large, the rate of change of the corrected firing angle β by the correction formula A2 is smaller than the rate of change of the corrected firing angle β by the correction equation A1 when the firing angle α is small . It is too big. In the illustrated example, the correction expressions A1 and A2 are as follows when the firing angles α and β are expressed in degrees.

[0016]

Β = 0.6α + 27 (correction formula A1) α = 0.15β + 153 (correction formula A2) After step S13 or S14, the CPU 31 advances the control operation to step S15 and corrects this correction point. An AC voltage having the arc angle β is supplied to the AC fan 25 via the fan drive circuit 29 to drive the AC fan 25.

The change rate of the correction firing angle β is large when the firing angle α is larger than the predetermined value B, and small when the firing angle α is smaller than the predetermined value B. Therefore, the correction firing angle β is used instead of the firing angle α. If the rotation speed of the AC fan 25 is controlled using the
Compared with the change characteristic D when the firing angle α is used as it is.
Is large, the gradient is small, and when the firing angle α is small, the gradient is small. That is, as shown by a curve C in FIG. 4, a characteristic closer to a proportional characteristic than the conventional characteristic D is obtained. As a result, the rate of change of the rotational speed of the AC fan 25 in the range where the firing angle α is large is large. Therefore CPU
Even in the range where the firing angle α calculated by 31 is large, the rotation speed of the AC fan 25 changes quickly according to the change of the firing angle α.

Next, an example in which the AC fan is operated at 50 Hz will be described.

A) When the firing angle is changed to 2300 revolutions / minute from the AC fan that has been rotating at 2650 revolutions / minute (maximum rotation speed) at a firing angle of 180 degrees, the rotation speed becomes 2335 revolutions / minute.
Time required to decrease to revolutions / minute (90% of the total change amount) 4.5 seconds in the conventional technology (using firing angle α as it is) 4.5 seconds in this embodiment (using correction firing angle α) 8 seconds b) The AC fan that was also running at 2650 rpm
When the firing angle is changed so as to be 00 revolutions / minute,
Time required for the rotation speed to decrease to 1885 revolutions / minute (90% of the total change amount) 2.2 seconds in the prior art 1.9 seconds in the present embodiment As described above, according to the present embodiment, the prior art The change in the rotation speed is more rapid than in the case of, especially when the rotation speed is changed by a relatively small amount near the maximum rotation speed, the difference in the change speed of the apparatus becomes remarkable.

In a conventional instantaneous water heater using an AC fan 25 having a rotation speed change characteristic as shown by a curve D in FIG. 4, the tapping temperature and the tapping amount are increased when the exhaust passage resistance is increased due to exhaust blockage or the like. When the AC fan 25 is operated near the maximum capacity and increases, the AC fan 25 approaches the maximum rotation speed.
Reduces the opening of the proportional solenoid valve 24 and simultaneously sets the firing angle α
Decrease. However, in the prior art, since the rate of change of the rotational speed of the AC fan 25 is small, it takes time for the rotational speed to decrease and the amount of combustion air to decrease.
Immediately decreases the opening and reduces the gas supply,
Problems such as a temporary excess of air and an unstable combustion state due to the lift of the flame of the gas burner 20 occur. Alternatively, in the case of the limit control in which the rotation speed of the AC fan 25 is detected to limit the change in the opening degree of the proportional solenoid valve 24 so that the air-fuel ratio does not deviate from the set range, the decrease in the gas supply amount is limited. Inconveniences such as a temporary rise in temperature occur.

On the other hand, according to the above-described embodiment, even when the AC fan 25 is operating near the maximum rotational speed as described above, the AC fan 25 has a large rate of change in rotational speed, so that the amount of hot water is rapidly increased. In response to this, the rotation speed is immediately reduced to reduce the amount of combustion air, so that the combustion state does not become unstable or the tapping temperature rises even temporarily.

Although the above embodiment has been described with respect to an example in which the rotation speed of the AC fan is controlled by phase control, the present invention is not limited to this, and is also applicable to the case where the rotation speed of the AC fan is controlled by voltage control. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a rotation speed control device of an AC fan in a gas combustion device according to the present invention.

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

FIG. 3 is a flowchart of a control program for controlling the rotation speed of the AC fan according to the present invention.

FIG. 4 is a diagram showing characteristics when the rotation speed of an AC fan is controlled by phase control.

FIG. 5 is a diagram illustrating a relationship between a firing angle and a corrected firing angle according to the present invention.

FIG. 6 is a diagram illustrating a configuration of a rotation speed control device of an AC fan in a conventional gas combustion device.

FIG. 7 is an explanatory diagram of a voltage waveform used for phase control.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main control means, 2 ... Control amount calculation means, 3 ... Fan drive means, 4 ... Control amount conversion means, 25 ... AC fan.

Continuation of the front page (56) References JP-A-1-269821 (JP, A) JP-A-2-178558 (JP, A) JP-A-4-365996 (JP, A) JP-A-62-259312 (JP) JP-A-62-178817 (JP, A) JP-A-3-122417 (JP, A) JP-A-63-67757 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB Name) F23N 3/08

Claims (1)

(57) [Scope of request for utility model registration] 1. A driven by an AC motor and fan you supply <br/> the combustion air, before notated § emissions controls the gas supply amount according to the control input such as a detected temperature and the set temperature a main control means for setting the rotational speed of the set rotational speed and the previous SL
Fan driving control quantity calculating means for calculating a control amount for controlling the rotational speed of the notated § down before by comparing the actual rotational speed of the fan, the notated § down before on the basis of the control amount in the rotation speed control device of the fan that put the gas burning appliance comprising a driving means, the control amount calculated by the control amount calculating means rate of change in range the control amount is large the control amount is small range a control quantity conversion means for converting the correction control amount such that the larger than the change rate in the fan drive means gas burning appliance and drives the notated § down before on the basis of this correction control amount rotation speed control device of the fan that put on.