JPS6038542A - Automatic ventilating fan - Google Patents

Abstract

PURPOSE:To enable to notice the polluted state in color by a method wherein the actions of the outputs of a gas sensor are set in a plurality of stages and the detection style of a gas sensor is made to be correspond to the lightening order of light emitting diodes or, for example, to the order of green, yellow and red light emitting diodes and a ventilating fan is put into operation only when the last red light emitting diode is lit. CONSTITUTION:When a gas sensor 2 is brought into contact with a gas such as tobacco fumes or the like, the voltage across load resistance 8 rises. As a result, the output voltage of the sensor is amplified by an operational amplifier 13, resulting in developing a voltage across output terminal. The outputted voltage causes operational amplifiers 21-23 to actuate in response to the respective set voltage at the first, second and third stages, resulting in lightening light emitting diodes, which are connected to the outputs of the operational amplifiers 21-23, in order. When the output is maximum, a current flows in the diode of a photocoupler 34 and consequently a bidirectional thyristor 37 is put into actuation by a CdS resistor so as to lighten the red light emitting diode and simultaneously to operate a fan motor 38.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an automatic ventilation fan that senses gas such as cigarette smoke and operates automatically.

Conventional configurations and their problems In recent years, demand for automatic ventilation fans has gradually increased in the market as gas sensors have progressed.

Under these circumstances, automatic ventilation fans with stable operating characteristics and high reliability are being highly valued.

The conventional automatic ventilation fan as described above will be explained below with reference to FIGS. 1 and 2.

100 is a conventional ventilation fan body, 101 is a semiconductor gas sensor whose main component is tin oxide, and 102 is a light emitting diode that serves as an operation indicator light that is lit when the ventilation fan is operated by the semiconductor gas sensor 101.

103 is a power supply, 104 is a transformer, and the secondary side has two outputs, one for the heater of the semiconductor gas sensor and the other for the low voltage circuit.
It has a variety. 105 is a load resistance on the output side of the semiconductor gas sensor 101, and a diode 106. resistance 1
07 and 108 are connected to input the output signal of the semiconductor gas sensor 101 to the inverting input terminal of the operational amplifier 1090.

110 is a rectifier bridge connected to the low voltage circuit output of the transformer 104, and is smoothed to a DC voltage by an electrolytic capacitor 111. Resistors 112 and 113 are connected to the plus side and minus side of the DC voltage, and the voltage dividing point is connected to the non-inverting input terminal of the OP amplifier 109, and is input as a setting signal. 1
Reference numeral 14 denotes a hysteresis resistor that provides hysteresis to the output characteristics of the OP amplifier 109 with respect to the signal from the semiconductor sensor 101.

115 is a transistor whose base is connected to the output of the OP amplifier 109, and whose emitter is connected to the negative side of the DC voltage. An electromagnetic coil of a DC relay 116 is connected to the collector, and a contact 117 operates a fan motor 118 of a ventilation fan.

The operation of the automatic ventilation fan configured as described above will be explained below.

First, when cigarette smoke or the like comes into contact with the semiconductor gas sensor 101, the electrical resistance value of the gas sensor 101 decreases. Therefore, the voltage across the load resistor 105 becomes high. The voltage across the diode 106° resistor 107, 108 connected in parallel also becomes high, and the inverting input terminal of the op amp 109 becomes
The voltage becomes higher than the non-inverting input terminal set by the resistors 112 and 113, and the transistor 115 connected to the output of the ○P amplifier 109 operates.

The DC relay 116 connected to the collector of the transistor 116 operates, and the contact 17 causes the fan motor 118 of the ventilation fan to operate, and at the same time, the light emitting diode 1o2
lights up to indicate operation.

However, although the above configuration works against tobacco smoke, it has the disadvantage that problems such as unstable operation due to concentration distribution and repeated operation due to malfunction may actually occur. was.

Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention has been developed to increase the output of a gas sensor by three steps.
The system provides an automatic ventilation fan that measures the stability of its operation in stages.

Structure of the Invention In order to achieve this object, the automatic ventilation fan of the present invention divides the output of the gas sensor into three stages for operation.
Use three controllers, for example, light up a green light emitting diode in the first stage, a yellow light emitting diode in the second stage, a red light emitting diode in the third stage, and only when the third stage is reached. With this configuration, the contamination status of cigarette smoke is displayed using light emitting diodes in three colors: green, yellow, and red, and at the same time, the ventilation fan is operated only at the third maximum stage. By operating the machine, the operation can be made relatively stable.

DESCRIPTION OF EMBODIMENTS Examples of the present invention will be described below with reference to FIGS. 3 to 6.

In the figure, 1 is the automatic ventilation fan body, 2 is a semiconductor gas sensor whose main component is tin oxide, 3 is a green light emitting diode,
4 is a yellow light emitting diode, and 6 is a red light emitting diode, which lights up in accordance with the output of the semiconductor gas sensor.

6 is a power supply, 7 is a transformer, and the secondary side is a semiconductor gas sensor 2
There are two types of output: one for heaters and one for low voltage circuits. 8 is a load resistance on the output side of the semiconductor gas sensor 2, and a diode 9 and a resistor 10.11 are connected in parallel.
The output signal of the semiconductor gas sensor 2 is passed through the resistor 12
It is input to the inverting input terminal of the amplifier 13.

14 is a rectifier bridge connected to the output of the transformer 7 for the low voltage circuit, and is smoothed into a DC voltage by an electrolytic capacitor 15. A constant voltage diode 16 is connected to the connection point between the resistors 1o and 11 and the negative side of the DC voltage, and serves to suppress the output voltage to a certain level so that the sensor output voltage does not rise suddenly.

Resistors 17 and 18 are connected to the positive and negative sides of the DC voltage, and the voltage dividing point is connected to the non-inverting input terminal of the OP amplifier 13 through a resistor 19. \20 is resistance. 21. 22.23 is an OP amplifier and the inverting input terminal is 3
Both are connected to the output of the operational amplifier 13.

Resistors 24, 25, 26, 27 are connected in series, resistor 2
The other end of the resistor 27 is connected to the negative side of the DC voltage, and the other end of the resistor 27 is connected to the positive side of the DC voltage.

The voltage dividing point between the resistor 24 and the resistor 250 is connected to the non-inverting input terminal of the OP amplifier 21, the voltage dividing point between the resistor 25 and the resistor 260 is connected to the non-inverting input terminal of the OP amplifier 22, and the voltage dividing point between the resistor 26 and the resistor 27 is connected to the OP amplifier 21. 23 non-inverting input terminals. 2B and 29°3o are hysteresis resistors. 31.32.

33 are green light emitting diodes 3.33 connected to the outputs of the op-amps 21, 22, and 23, respectively. Yellow light emitting diode 4. This is the current limiting resistor for the red light emitting diode.

(34 is a photocoupler formed of a light emitting diode and a CdS resistor, and the light emitting diode portion is connected in parallel to the red light emitting diode 5 and to the gate of the bidirectional thyristor 37.

A fan motor 38 of a ventilation fan is connected to the T2 side terminal of the bidirectional thyristor 37.

Reference numeral 39 represents an output characteristic curve for the degree of contamination of the gas sensor 2 with tobacco smoke, and the output characteristic curve is operated by the first, second, and third stage OP amplifiers 21, 22, and 23 depending on the degree of contamination.

4o is a characteristic curve of the resistance value of the CdS resistor of the photocoupler 34 with respect to the current in the diode portion, and as the current flows through the diode portion, the resistance value of the CdS resistor decreases.

The operation of the automatic ventilation fan configured as above will be explained below.

First, when the gas sensor 2 comes into contact with gas such as cigarette smoke, the voltage across the load resistor 8 increases. The output voltage of the sensor is then amplified by the OP amplifier 13, and the voltage appears at the output terminal.

As shown in FIG. 5, the output voltage is set to each of the set voltages of the first, second, and third stages [2, OP amplifier 21.
It moves 22, 23.

The light emitting diodes connected to the outputs of the OP amplifiers 21, 22, and 23 then light up in sequence. When the output is at its maximum, current flows through the diode of the photocoupler 34, and the bidirectional thyristor 3
7, the fan motor 38 can be operated simultaneously with the lighting of the red light emitting diode 60.

Effects of the Invention As described above, the present invention sets the operation of the gas sensor output in multiple stages, and depending on the sensing condition of the gas sensor, for example, a green light emitting diode, a yellow light emitting diode, and a red light emitting diode are turned on in order, and the last light emission is By operating the ventilation fan only at the diode, the operational stability and contamination status can be determined by the color, which has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a front view of a conventional automatic ventilation fan, FIG. 2 is an electrical circuit diagram of a conventional automatic ventilation fan, FIG. 3 is a front view of an automatic ventilation fan according to an embodiment of the present invention, and FIG. 4 is an automatic ventilation fan of the present invention. Electric circuit diagram of a ventilation fan, FIG. 6. Characteristic curve of sensor output of the automatic ventilation fan of the present invention. FIG. 6 is a change curve of resistance value of a CdS resistor of a photocoupler with respect to diode current. 2... Semiconductor gas sensor, 7... Transformer, 13゜21.22.23...--OP amplifier,
34...Photocoupler, 37...Bidirectional Sairisk.

Claims (1)

[Claims] A semiconductor gas sensor that detects gas and cigarette smoke, an OP amplifier that amplifies the sensor output formed by a resistor connected to the semiconductor gas sensor, and a diode that converts the signal into direct current, and multiple amplified sensor signals. A comparator formed by several OP amplifiers, a plurality of light emitting diodes of different colors connected to the output of each of the OP amplifiers, a photocoupler diode connected in parallel to the light emitting diode at maximum output, and a photocoupler It has a bidirectional thyristor with a CdS resistor connected to a gate circuit, and a fan motor connected to this thyristor, which lights up light emitting diodes of different colors depending on the magnitude of the output of the semiconductor gas sensor. Automatic ventilation fan that operates the fan motor using a bidirectional thyristor at the same time as the light emitting diode turns on when outputting.