JP2000161733A - Automatic ventilation fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic ventilation fan for preventing an erroneous operation due to the decrease in a power supply voltage in advance. SOLUTION: An automatic ventilation fan is provided with an AD conversion means 13 for covering the resistance of a gas sensor 8 to a signal voltage, taking in the signal voltage at each fixed time, and converting it to a digital signal; a storage means 15 for storing post digital signals; an air quality-judging means 16 for comparing the digital signal with the stored digital signals by a comparison means 14, outputting the stored digital signal when there is a difference exceeding a prescribed value, and judging the degree of contamination of air based on the outputted digital signal; and a fan operation-judging means 17 for determining the operation and stop of the fan motor 1 based on the judgment of the air quality-judging means 16, thus preventing an erroneous operation in advance when a power supply voltage drops by automatically operating and stopping the fan motor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ventilating fan which automatically detects the indoor air pollution and operates automatically.

[0002]

2. Description of the Related Art In recent years, there has been increasing interest in indoor air quality, and as the number of ventilation fans installed inside a house has increased and ventilation equipment has been improved, the degree of indoor air pollution has been sensed.
There is an increasing demand for an automatically operated ventilation fan that can automatically provide efficient ventilation.

Conventionally, as this kind of automatic ventilation fan, for example, the one shown in FIG. 8 has been known. Hereinafter, the configuration will be described with reference to FIG.

[0004] As shown in the figure, a gas sensor 108 whose resistance value changes according to a change in environment, and a gas sensor 108.
A sensor means 104 comprising a heater 109 for activating the heater, a heater voltage applying means 111 for applying a voltage to the heater 109, and a voltage converting means 112 for converting a resistance value of the gas sensor 108 into a signal voltage. A / D conversion means 113 for taking in the voltage at fixed time intervals and converting it into a digital signal, and air quality determination means 116 for obtaining the degree of air contamination based on the output digital signal.
And a fan operation determination unit 1 that determines the operation and stop of the fan motor 101 based on the result of the air quality determination unit 116.
17 and the fan motor 101 when the fan operation determination means 117 determines the operation.
Driving means 118 for driving the motor and automatic driving means 11
9 and a control unit 107 comprising
The operation and stop of the fan motor 101 were automatically performed.

[0005]

In such a conventional automatic ventilation fan, when an instantaneous power failure occurs, the power supply voltage temporarily drops, and the temperature of the heater 109 for activating the gas sensor 108 drops. For the gas sensor 1
Since the signal 08 changes as if the indoor air was contaminated, an erroneous signal is transmitted to the air quality determining means 116 for determining the degree of air contamination, and the erroneous result is transmitted to the fan operation determining means 117. , An erroneous determination is made and the fan motor 101 malfunctions. In order to avoid such a malfunction, a special means for separately determining a drop in the power supply voltage is required, which increases the cost and increases the number of parts, and causes adverse effects in downsizing the device. There was a problem.

An object of the present invention is to solve the above-mentioned problems and to provide an inexpensive and small-sized automatic ventilation fan which does not require any special means for judging a decrease in power supply voltage.

[0007]

In the control device for an automatic ventilation fan according to the present invention, a gas sensor whose resistance value changes in accordance with an environmental change, a heater for activating the gas sensor, and a voltage applied to the heater. Heater voltage applying means for applying, voltage converting means for converting the resistance value of the gas sensor into a signal voltage, AD converting means for taking in the signal voltage at regular time intervals and converting the signal voltage into a digital signal, Storage means for storing digital signals;
The digital signal is compared with the past digital signal stored in the storage means, and if there is a difference equal to or more than a specified value, the digital signal is ignored, the past digital signal is output, and the difference smaller than the specified value is output. In the case of, the comparing means for outputting the digital signal, the air quality determining means for determining the degree of air contamination based on the digital signal output from the comparing means, Fan operation determining means for determining the operation and stop of the fan motor,
A fan drive unit for driving the fan motor when the fan operation determination unit determines the operation is provided, and the fan motor is automatically operated and stopped.

According to the present invention, it is possible to provide an inexpensive and small-sized automatic ventilation fan which does not require any special means for judging a drop in the power supply voltage, and which can prevent the malfunction of the device beforehand.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided a gas sensor whose resistance value changes in accordance with an environmental change, a heater for activating the gas sensor, and a voltage applied to the heater. Heater voltage applying means, voltage converting means for converting the resistance value of the gas sensor into a signal voltage, AD converting means for taking in the signal voltage at regular intervals, and converting the signal voltage into a digital signal, The storage means for storing the signal, the digital signal is compared with the past digital signal stored in the storage means, if there is a difference greater than a specified value, the digital signal is ignored, the past A comparing unit that outputs a digital signal and outputs the digital signal when the difference is smaller than a specified value; and based on the digital signal output by the comparing unit, air contamination. And air quality determining means for determining an eye,
A fan operation determining unit that determines operation and stop of the fan motor based on the determination by the air quality determining unit; and a fan driving unit that drives the fan motor when the fan operation determining unit determines the operation. The configuration is such that the operation and stop of the fan motor are automatically performed, and has the effect of preventing a malfunction of the fan motor in advance when the power supply voltage temporarily drops due to an instantaneous power failure or the like.

An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) As shown in FIGS. 1 to 3, a fan motor 1 is provided inside, and a switch 3 for selecting an automatic operation mode or a continuous operation mode is provided on a ventilation fan main body 2 mounted on a wall surface 6. , Indoor air pollution degree is CO2
A sensor means 4 for sensing a change in the concentration of gas or tobacco smoke, an operation state display lamp 5, and a control unit 7 for controlling the operation of the fan motor 1 are provided.

The control unit 7 controls the heater driving means 1
Heater voltage applying means 11 for converting a signal of 0 into a voltage
And voltage conversion means 12 for converting the resistance value of the gas sensor 8 into a signal voltage, AD conversion means 13 for taking in the signal voltage at regular intervals and converting the signal voltage into a digital signal, and storing the output past digital signal. Storage means 15 for storing
And the digital signal just converted is compared with the past digital signal stored in the storage means 15. If there is a difference equal to or more than a specified value, the converted digital signal is ignored and the past digital signal is ignored. Means 14 for outputting
Air quality determining means 16 for determining the degree of air contamination based on the digital signal output from the comparing means 14, and a fan for determining operation and stop of the fan motor 1 based on the determination by the air quality determining means 16. The configuration includes an operation determining unit 17 and a fan driving unit 18 that drives the fan motor 1 when the fan operation determining unit 17 determines the operation.

The automatic driving means 19 includes a central processing unit (CPU), an input / output device, and an AD conversion input device (A / A /
D), a so-called one-chip microcomputer incorporating a read-only memory (ROM) and a read / write memory (RAM).

In the above configuration, when an instantaneous power failure occurs, the power supply voltage temporarily drops, the temperature of the heater 9 for activating the gas sensor 8 drops, and the gas sensor 8
The operation in the case where the signal from has an abnormal value will be described with reference to FIG.

The heater driving means 10 outputs a pulse signal for setting the heater voltage to a specified voltage, the heater voltage applying means 11 converts the pulse signal into a voltage signal, and applies this voltage to the heater 9. The gas sensor 8 activated by the heat generated by the heater 9 has a structure in which the resistance value changes when room air is contaminated with CO2 gas or cigarette smoke. After the change in the resistance value is converted into a change in voltage by the voltage conversion means 12, it is converted into a digital signal by the AD conversion means 13 at regular intervals. The digital signal is compared by the comparing means 14 with the past digital signal stored in the storage means 15 to determine whether or not a change of a difference equal to or more than a specified value has occurred. This specified value is set to a value larger than a value based on a digital signal due to possible air pollution, so that the gas sensor 8 is operating normally or the signal from the gas sensor 8 is an abnormal value. Can be determined.

During normal operation, no difference exceeding the specified value is generated, so that the digital signal is inputted to the air quality judging means 16 and converted into a pollution concentration value of the indoor air. The determination means 17 determines whether or not to operate the fan motor 1, and the fan drive means 18 automatically operates the fan motor 1.

If the power supply voltage decreases and the voltage applied to the heater 9 decreases, the amount of heat generated by the heater 9 decreases and the activation of the gas sensor 8 is suppressed. Therefore, the signal from the gas sensor 8 changes as if the indoor air was rapidly polluted. Therefore, when the signal from the gas sensor 8 is used as it is, the fan motor 1 is erroneously operated even though the indoor air is not polluted. In order to avoid this in advance, according to the present invention, after converting the resistance value of the gas sensor 8 into a digital signal, this digital signal is compared with the comparison means 1.
In step 4, it is compared with the past digital signal stored in the storage means 15 to determine whether or not the change is greater than a specified value. The output of the digital signal is stopped, and the stored past digital signal is output. Then, the output digital signal is stored in the storage means 15 and used for the next comparison.

As described above, according to the automatic ventilation fan of the first embodiment of the present invention, after converting the resistance value of the gas sensor 8 into a digital signal, the digital signal is stored in the storage unit 15 by the comparison unit 14. If the difference from the past digital signal is less than the specified value, it is output as a normal value, and if the difference is more than the specified value, it is judged as abnormal and the digital signal is output Is stopped, and a past digital signal is output, so that when the power supply voltage temporarily drops due to an instantaneous power failure, malfunction of the fan motor can be prevented.

(Embodiment 2) As shown in FIG. 4, a structure in which a heater temperature compensating means 30 for temporarily increasing a heater applied voltage after avoiding a malfunction of a fan motor due to a drop in power supply voltage is provided. It was done.

In the above configuration, when an instantaneous power failure occurs, the power supply voltage temporarily drops, the temperature of the heater 9 for activating the gas sensor 8 drops, and the signal from the gas sensor 8 becomes an abnormal value. In this case, malfunction of the fan motor 1 is prevented, as in the first embodiment.
Further, the temperature of the gas sensor can be quickly returned to the state before the abnormality by temporarily increasing the heater applied voltage in accordance with the command from the heater temperature compensating means 30.

As described above, according to the automatic ventilation fan of the second embodiment of the present invention, after the malfunction of the fan motor 1 is avoided due to a temporary decrease in the power supply voltage such as an instantaneous power failure, the heater temperature compensating means 30 causes Since the applied voltage is temporarily increased, the temperature of the gas sensor can be quickly returned to the state before the abnormality, and an automatic ventilation fan capable of performing more stable automatic operation can be provided.

(Embodiment 3) As shown in FIGS. 5 to 7, a configuration is provided in which a specified value changing means 31 for determining a specified value to be used by a comparing means based on the value of a digital signal is provided. is there.

In the above configuration, when an instantaneous power failure occurs, the power supply voltage temporarily drops, the temperature of the heater 9 for activating the gas sensor 8 drops, and the gas sensor 8
The operation in the case where the signal from has an abnormal value will be described with reference to FIG.

The heater driving means 10 outputs a pulse signal for setting the heater voltage to a specified voltage, and the heater voltage applying means 11 converts the pulse signal into a voltage signal.
This voltage is applied to the heater 9. The gas sensor 8 activated by the heat generated by the heater 9 detects that the indoor air
2. The structure is such that the resistance value changes when polluted by gas or tobacco smoke. After the change in the resistance value is converted into a change in voltage by the voltage conversion means 12, the signal is converted into a digital signal by the AD conversion means 13 at regular intervals. This digital signal is compared with the past digital signal stored in the storage unit 15 by the comparison unit 14 to determine whether or not the difference is equal to or greater than a specified value.

Here, when an instantaneous power failure occurs, generally, as shown in FIG. 6, the amount of drop of the digital signal, which is the difference between the digital signal and the stored past digital signal, is reduced by the digital signal. And is proportional to the instantaneous power outage time. That is, for the instantaneous power failure time t, t3 <t2
When there is a relationship of <t1, the value of the digital signal D is D1
, The digital signal drop amount dD is dD3 <dD2 <
dD1, and as the instantaneous power failure time t becomes longer, the digital signal drop amount dD becomes larger.

Then, the instantaneous power failure time t that can actually occur
Is a time slightly longer than t2 (for example, 200 ms), as in the invention described in the first embodiment, the prescribed value used by the comparing means 14 is a constant value regardless of the value of the digital signal. When this value is plotted above a straight line at t = t2 in FIG. 6 in a certain digital signal, when the resistance value of the gas sensor 8 is the value of the digital signal, the comparing means 14 The momentary power failure cannot be detected. That is, the comparison means 1
The specified value used in 4 must be below the straight line at t = t2 for any digital signal value.

That is, the relationship between the digital signal and the specified value used to determine whether the difference between the digital signal and the past digital signal is abnormal is stored in the specified value changing means 31 as a graph shown in FIG. However, by determining the specified value based on the value of the digital signal, it is possible to more reliably detect an instantaneous power failure that can actually occur.

As described above, according to the automatic ventilation fan of the third embodiment of the present invention, after the resistance value of the gas sensor 8 is converted into a digital signal, the specified value is obtained by the specified value changing means 31, and the comparing means 14 The digital signal and storage means 1
5 is compared with the past digital signal, and when this difference is less than the specified value, the difference is used as a normal value;
When the value is equal to or more than the specified value, it is determined that the power supply is abnormal, the output of the digital signal is stopped, and the past digital signal is output. Therefore, an instantaneous power failure that can actually occur can be more reliably detected.

[0029]

As is apparent from the above embodiments, according to the present invention, a gas sensor whose resistance changes according to a change in environment, a heater for activating the gas sensor, and a voltage applied to the heater Heater voltage applying means, a voltage converting means for converting the resistance value of the gas sensor into a signal voltage, an AD converting means for taking in the signal voltage at regular intervals and converting the signal voltage into a digital signal, Storage means for storing the digital signal of, and comparing the digital signal and the past digital signal stored in the storage means, if there is a difference of a specified value or more, ignore the digital signal, A comparing unit that outputs the digital signal in the past and outputs the digital signal when the difference is less than a prescribed value; and based on the digital signal output by the comparing unit. Air quality determining means for determining the degree of air contamination, fan operation determining means for determining operation and stop of the fan motor based on the determination of the air quality determining means, and fan operation determining means determining operation. Sometimes, a fan drive unit for driving the fan motor is provided, and the operation and the stop of the fan motor are automatically performed. Therefore, when the power supply voltage is temporarily reduced due to an instantaneous power failure, the malfunction of the fan motor is anticipated. Thus, it is possible to provide an inexpensive and small control device for an automatic ventilation fan that does not require any special means for judging a decrease in the power supply voltage.

Further, since the heater temperature compensating means for temporarily increasing the heater applied voltage after the recovery from the instantaneous power failure is provided,
It is possible to provide an automatic ventilation fan that can promptly return the temperature of the gas sensor to the state before the abnormality and that can perform more stable automatic operation.

Further, the provision of the specified value changing means for determining the specified value to be used by the comparing means based on the value of the digital signal fetched at regular time intervals makes it possible to more surely detect an instantaneous blackout that can actually occur. In addition, malfunction of the fan motor can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an automatic ventilation fan according to a first embodiment of the present invention.

FIG. 2 is a front view showing the configuration of the automatic ventilation fan.

FIG. 3 is a schematic sectional view showing a state where the automatic ventilation fan is attached to a wall surface.

FIG. 4 is a block diagram showing a configuration of an automatic ventilation fan according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of an automatic ventilation fan according to a third embodiment of the present invention.

FIG. 6 is a graph showing a digital signal drop amount when an instantaneous power failure of the automatic ventilation fan occurs.

FIG. 7 is a graph showing a relationship between a prescribed value determined by a prescribed value changing means of the automatic ventilation fan and a digital signal.

FIG. 8 is a block diagram showing a configuration of a conventional automatic ventilation fan.

[Explanation of symbols]

 Reference Signs List 1 fan 8 gas sensor 9 heater 11 heater voltage application means 12 voltage conversion means 13 AD conversion means 14 comparison means 15 storage means 16 air quality determination means 17 fan operation determination means 18 fan drive means 30 heater temperature compensation means 31 specified value change means

Claims (3)

[Claims] 1. A gas sensor whose resistance value changes according to a change in environment, a heater for activating the gas sensor, heater voltage applying means for applying a voltage to the heater, and a resistance value of the gas sensor. Voltage conversion means for converting to a signal voltage, AD conversion means for taking in the signal voltage at regular time intervals and converting the signal voltage to a digital signal, storage means for storing the output past digital signal, and the digital signal Compare with the past digital signal stored in the storage means, if there is a difference greater than a specified value, ignore the digital signal, output the past digital signal, with a difference less than the specified value In some cases, comparing means for outputting the digital signal, air quality determining means for determining the degree of air contamination based on the digital signal output by the comparing means, A fan operation determining unit that determines operation and stop of the fan motor based on the determination of the air quality determining unit; and a fan driving unit that drives the fan motor when the fan operation determining unit determines the operation. An automatic ventilation fan that automatically starts and stops the motor. 2. The automatic ventilation fan according to claim 1, further comprising a heater temperature compensation means for increasing a heater drive voltage. 3. The automatic ventilation fan according to claim 1, further comprising a specified value changing means for determining a specified value to be used by the comparing means based on a value of the digital signal taken at predetermined time intervals.