JPS60159536A - Automatic control device for humidifier - Google Patents

Abstract

PURPOSE:To constitute the automatic control device for humidifier capable of effecting control, good in response and small in the ripple of humidity, by employing a humidity sensor having humidity-electric resistance characteristic. CONSTITUTION:A differential voltage (Ve-Vf) between the output voltage Ve of a humidity detecting circuit 46, which is based on the humidity detection of the humidity sensor 33, and a reference voltage Vf corresponding to the set humidity of a humidity setting circuit 53 is detected by a differential voltage detecting circuit 58 and the oscillating output of a LC oscillation circuit 9 is controlled in two steps in accordance with the magnitude of the differential voltage (Ve- Vf) to switch automatically strong humidifying operation and weak humidifying operation step wisely. Accordingly, the weak humidifying operation is effected surely when an ambient humidity is closed to the set humidity and the control of regulation of humidity, in which the ripple of humidity is small, may be effected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic control device for a humidifier that automatically adjusts the humidity of an atmosphere to be humidified, such as a room.

(Technical Background of the Invention) Conventional automatic control devices of this type include a humidity sensor using a nylon film that expands and contracts depending on the humidity, and uses this humidity sensor to turn on and off a microswitch.
Generally, when the microswitch is turned on, the humidifier is operated at a constant output, and when it is turned off, the humidifier is stopped.

[Problems with background technology]

In the above configuration, the humidity sensor is a mechanical humidity sensor that uses the expansion and contraction of a nylon film, so the response is poor, and since the humidifier is simply controlled intermittently using a microswitch, the humidity ripple is large. There is.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its object is to provide a humidifier that can be controlled with good responsiveness and with little humidity ripple by using a humidity sensor having humidity-electrical resistance characteristics. Located in providing automatic control equipment.

[Summary of the invention]

The present invention includes a humidity sensor that changes an electrical resistance value according to humidity, a humidity detection circuit that converts the electrical resistance value of the humidity sensor into a voltage, and a humidity setting circuit that outputs a desired humidity as a voltage. , a voltage difference detection circuit that outputs the output voltage difference between the humidity detection circuit and the humidity setting circuit is provided, and a control circuit is provided that changes the humidifier output in stages according to the output voltage of the voltage difference detection circuit. The humidifier is characterized by the structure in which the humidifier is made smaller as the atmospheric humidity approaches the set humidity.

[Embodiments of the invention]

Hereinafter, an embodiment in which the present invention is applied to an ultrasonic humidifier will be described with reference to the drawings.

In FIG. 1, a fan motor 1 is provided to discharge mist generated in accordance with the driving of an ultrasonic vibrator 2 to the outside of the ultrasonic humidifier. A C connection is made between them via a power switch 4. A primary coil 5a of a step-down transformer 5 is connected in parallel with the fan motor 1, and a secondary coil 5b of the step-down transformer 5 is constructed by connecting four diodes in a bridge as shown. It is connected to lines Ll and C2 via a wave rectifier circuit 7. Therefore, a DC voltage with a high potential on the line Li side is held between the lines L1 and 12, and a smoothing capacitor 8 is connected between the lines L1 and C2. A well-known LC oscillation circuit 9 for driving the ultrasonic transducer 2 is connected to a line 1.
The LGC oscillation circuit 9 is connected to the LGC oscillation circuit 9, and the connection relationship between the LGC oscillation circuit 9 and the line C2 will be described below. That is, in the oscillating NPN transistor 10 -C
1) The receiver connects the line L through the choke coil 11.
1, and the emitter is connected to line 2, and furthermore, between the base and line L2, a resistor 12 and a variable resistor 13 for setting the oscillation output are connected in parallel.

Further, a capacitor 14 is connected between the collector of the transistor 10 and the 1-transistor 10, and a capacitor 15 and the ultrasonic vibrator 2 are connected in series between the collector and the base of the 1-transistor 10. The ultrasonic sensor 2 is disposed at the bottom of a water tank (not shown) of the ultrasonic humidifier, and when excited by the C oscillation circuit 9, generates ultrasonic waves to atomize the water in the water tank. It is structured in such a way that it allows you to

On the other hand, a constant voltage circuit 18 consisting of a series circuit of a resistor 16 and a cross-section diode 17 with the polarity shown is connected between the lines 11 and 1-2, and is therefore connected to both terminals of the cross-section diode 17. A constant DC voltage is output between the lines L3 and [-2.A square wave generation circuit 19 is connected between the lines L3 and 1-2. In other words, a resistor 20, 21 and a diode 22 having the polarity shown are connected in series between the lines L3 and 12, thereby forming a circuit for dividing the output voltage of the constant voltage circuit '18.

The positive input terminal (10) of the operational amplifier 23 is connected to the line L2 via a time constant capacitor 24 and the diode 22, and is also connected to the line 1-3 via a resistor 25, and further connected to the line L2 through a resistor 25. The input terminal (+) is connected to the C line C2 via a resistor 26 and a diode 22.

Further, a resistor 27 is connected between the output terminal and the negative input terminal (-) of the operational amplifier 23, and a resistor 28 is connected between the output terminal of the operational amplifier 23 and the positive input IP (10). So-C1 operational amplifier 23. Capacitor 24. The resistors 25°, 26, 27, and 28 form an h-wave oscillator 29 of a well-known configuration, and a square-wave voltage Va having a waveform shown in FIG. 4(a) is output from this square-wave oscillator 29. Further, in the square wave generation circuit 19, the square wave voltage Va is applied to the negative input terminal (-) of the operational amplifier 30 which acts as an inverting circuit, and the positive input terminal (-) of the operational amplifier 30 acts as an inverting circuit. ), a constant DC voltage is input from the common connection point of the resistors 20 and 21. Therefore, the operational amplifier 30 outputs the square wave voltage Va as shown in FIG.
) is output as shown in FIG. It will be output.

The electrical resistance type humidity sensor 33.32 is connected between the output terminals 31.32 in FIG. 1 so that the square wave AC voltage is applied thereto.
Resistors 34, 35 and -Reamister 36 are connected in series, a resistor 37 is connected in parallel with the series circuit of humidity sensor 33 and resistor 34, and resistor 38 is connected in parallel with Reamister 36. The humidity sensor 33 is arranged to sense the atmospheric humidity around the ultrasonic humidifier, and an example of its specific configuration is shown in FIG. That is,
The humidity sensor 33 includes a ceramic porous sintered body 40 disposed in a case 39 having a ventilation net 39a on the circumferential side, and lead wires drawn out from both opposing sides of the porous sintered body 40. 41° 41 are connected to terminals 42 and 42, and the resistance value decrease between terminals 4' and 2 and 42 due to the water molecule adsorption phenomenon of the porous sintered body 40 corresponds to the atmospheric humidity. Become. Therefore, the atmospheric humidity can be detected based on the voltage change characteristics of the detection terminal 43 (common connection point of the resistors 34 and 35) in FIG.

The equivalent circuit of this humidity sensor 33 is as shown in FIG. On the other hand, the thermistor 36 connected in series is for correcting the output voltage characteristic of the humidity sensor 33 (i.e., the output voltage characteristic from the detection terminal 43) according to the ambient humidity, and the resistor 34 .37
is provided for linearizing the output voltage characteristics of the humidity sensor 33, and a resistor 38 is provided for matching the characteristics of the thermistor 36. In addition, 44 is the detection terminal 43 and the line L.
This is a noise prevention capacitor connected between the two. 4
5 is an operational amplifier for output conversion, which is connected to the resistor 34.
．． 35, 37, 38 and the thermistor 36, it constitutes a humidity detection circuit 46, the positive input terminal (+) of which is connected to the output terminal, and the negative input terminal (-)
is connected to a detection terminal 43, and its output terminal is connected to an intermediate terminal 48 via a resistor 47. This intermediate terminal 48 is connected to the output terminal 32 via a diode 49 with the polarity shown, and a diode 5 with the polarity shown.
0 to an output terminal 51, and the output terminal 51 is connected to a line L2 via a smoothing capacitor 52.

Now, 53 is a humidity setting circuit, which is connected to line l-:
+, 12 resistor 54. It is constructed by connecting a series circuit of a variable resistor 55 and a resistor 56, and the sliding terminal 5 of the variable resistor 55
5a outputs a reference voltage vr corresponding to a desired set humidity R+-1a (see FIG. 5). 57 is an operational amplifier constituting the N weight detection circuit 58, the positive input terminal (+) of which is connected to the output terminal 51 via a resistor 59 and connected to the line L via a resistor 60.
2, and the negative input terminal (-) is connected to resistor 6.
1 to the sliding terminal 55a of the variable resistor 55, and is also connected to the output terminal via a resistor 62, and the output terminal is connected via a resistor 63 to the line L2.

On the other hand, 64 is a control circuit, which will be described below. That is, 65 and 66 are lines L1. The common connection point of the variable resistor 13 is connected to the variable resistor 13 via a diode lower of the polarity shown.
It is connected to the sliding terminal 13a of. 68 and 69 are N
They are PN type transistors, each emitter is connected to line L2, the collector of transistor 68 is connected to the common connection point of resistors 65 and 66 via resistor 70, and the collector of transistor 69 is directly connected to resistor 65 and 66 common connection points. Reference numerals 71 and 72 designate operational amplifiers as voltage comparison circuits, each of whose negative input terminal (-) is connected to the output terminal of the operational amplifier 57, and a resistor is connected between each positive input terminal (+) and the output terminal. 73 and 74 are connected, respectively, and their respective output terminals are connected to the respective bases of the one helangistors 68 and 69 via resistors 75 and 76, respectively. 77 is a reference voltage generation circuit, which is constructed by connecting resistors 78, 79 and 80 in series between lines L3 and L2, and the common connection point of the resistors 78 and 79 is connected to the positive input terminal (+) of the operational amplifier 71. ), and the common connection point of the resistors 79 and 80 is connected to the positive input terminal (+) of the operational amplifier 72.

Next, the operation of this embodiment will be explained.

When the power switch 4 is turned on, the fan motor 1 is energized and driven by the AC power supply 3, and a DC voltage is output between lines 1-1+12, and a constant DC voltage is output between lines 13 and 12. Output. Therefore, a base current flows to the transistor 10 via the diode 67 and the variable resistor 13 due to the voltage divided by the resistors 65 and 66, and the LC oscillation circuit 9 starts to perform an oscillation operation, and accordingly, the ultrasonic vibration The child 2 is driven and humidification operation is performed. In this case, when the base current flows through the transistor 10 due to the divided voltage of the resistors 65 and 66, the LC oscillation circuit 9 performs oscillation operation at maximum output.)
Therefore, the amount of humidification by the ultrasonic vibrator 2 is large and strong humidification operation is performed. On the other hand, Rai 2
By outputting a DC constant voltage between 13 and 12, the square wave generation circuit 19 is driven, and a square wave AC voltage is output between its output terminals 31 and 32 based on the square wave voltages Va and Vb. , this square wave AC voltage is applied to the humidity sensor 33. It is applied to a series circuit of resistors 34, 35 and thermistor 36. Then, the detection terminal 43 has a signal as shown in FIG. 4(C).
As shown, a detection voltage VC whose level changes depending on the electrical resistance value of the humidity sensor 33 (ie, atmospheric humidity) is output, and this is applied to the operational amplifier 45.

In this case, since the diode 49 is cut off when the square wave voltage Va is output to the output terminal 32, the detection voltage Vc is output to the width terminal 48 only during the output period of this square wave voltage Va. Therefore, an intermediate output voltage Vd is generated at the intermediate terminal 48, as shown in FIG. 4(d). Furthermore, this intermediate output voltage Vd is connected to the diode 5.
0 through the smoothing capacitor 52, a DC output voltage ■e is output to the output terminal 51 as shown in FIG. 4(e), and this output voltage ■e As shown in FIG. 5, where RH (%) is plotted on the horizontal axis, RH (%) exhibits a linear characteristic that decreases as the humidity increases. Since this output voltage Ve and the reference voltage V [for example, Vft] from the humidity setting circuit 53 are applied to the operational amplifier 57, the operational amplifier 57 receives the difference voltage (Ve - V
f t ) comes to be output', and this comes to be given to the negative input terminals (-) of operational amplifiers 71 and 72. Then, in the reference voltage generation circuit 77,
A reference voltage V (+ and -C is output to the common connection point of the resistors 78 and 79, and a reference voltage vh is output to the common connection point of the resistors 79 and 80, and these reference voltages Vg and V
h (V!J > Vb) is given to each positive input terminal (+) of the operational amplifiers 71 and 72, so the operational amplifiers 71 and 72 have the difference voltage <ve vr l
) and reference voltages VQ and V11, respectively. In this case, when the humidity of the humidified atmosphere such as indoors is low, the electrical resistance value of the humidity sensor 33 is high, and therefore the output voltage
is large, the differential voltage (Ve - Vft) is also large, and (Ve
-Vfs)>V(1, Vh, which means that A
The output signals of the pair amplifiers 71 and 72 are at low level. As a result, the atmospheric humidity gradually increases due to the strong humidification operation as described above, and the output voltage Ve gradually decreases.
-V[1) becomes smaller than the reference voltage VQ. In Fig. 5, humidity RHt and output voltage Vf2)1. The output signal of the d amplifier 71 becomes high level, turning on the transistor 68, and thereby the resistor 70 is connected in parallel to the resistor 66. Therefore, the divided voltage generated at the common connection point of the resistors 65, 66 and 70 becomes smaller, the base current of the transistor 10 decreases accordingly, the oscillation output of the LC oscillation circuit 9 becomes smaller, and the ultrasonic transducer 2 The amount of humidification caused by this decreases, and the operation can then be switched to weak humidification. After that, when the atmospheric humidity further increases and the differential voltage (Ve - Vft) becomes approximately zero, the atmospheric humidity becomes approximately the set humidity RH2, and the output voltage Ve
When becomes approximately equal to the reference voltage Vl'1, the A amplifier 72
The output signal of becomes high level and the transistor 69 is turned on, so that the resistor 66 is short-circuited and the base current no longer flows to the transistor 10, and the [-C oscillation circuit 9 stops its oscillation operation, humidification operation is stopped. Thereafter, when the atmospheric humidity becomes lower than the set humidity RH2, the above-described operation is repeated.

According to this embodiment, the following effects can be obtained. That is, since the atmospheric humidity is detected as a change in electrical resistance by the electrical resistance type humidity sensor 33, the response is better than that of a conventional mechanical humidity sensor using a nylon film. Further, the difference voltage (Ve - Vf) between the output voltage Ve from the humidity detection circuit 46 based on the humidity detection by the humidity sensor 33 and the reference voltage V[ corresponding to the set humidity from the humidity setting circuit 53 is detected by the difference voltage detection circuit 58. This difference voltage (Ve −
The oscillation output of the l-C oscillation circuit 9 is controlled in two stages according to the magnitude of
Since the humidity level is automatically switched, weak humidification operation is always performed when the atmospheric humidity approaches the set humidity, and adjustment control with less humidity ripple can be performed. Moreover, as mentioned above, when the atmospheric humidity gets close to the set humidity, the strong humidification operation switches to the weak humidification operation, so the user knows that the atmospheric humidity is low because the strong humidification operation is in progress, and the weak humidification is performed. It is extremely convenient to use because it is possible to know that the atmospheric humidity has increased to near the set humidity by switching to operation.

In the above embodiment, the control circuit 64 switches between the strong humidification operation and the weak humidification operation, but the transistor 68. By arranging more and more circuits each consisting of a combination of resistor 70 and operational amplifier 71 in parallel, it is possible to switch to three or more stages.

However, the present invention is not limited to the embodiments described above and not shown in the drawings, and can be modified as appropriate without departing from the scope, such as being applicable not only to ultrasonic humidifiers but also to humidifiers in general. Of course, it can be carried out as well.

(Effects of the Invention) As explained above, the humidifier automatic control device of the present invention has the following features:
Humidity sensor 4C uses an electric resistance type that changes the electric resistance value according to the humidity, and uses the output voltage from the humidity detection circuit based on the humidity detection of the humidity sensor and the standard from the humidity setting circuit that gives the set humidity. Since the humidifier output is changed in stages according to the voltage difference, it is possible to perform control with good responsiveness and little humidity ripple. It has excellent effects such as being extremely convenient to use since it is possible to know the degree of elevation.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is an overall electrical connection diagram, Fig. 2 is a schematic longitudinal sectional view of a humidity sensor, Fig. 3 is an equivalent circuit diagram of the temperature sensor, and Fig. 4. (a) to (e
) is an output voltage waveform diagram of each part for explaining the operation, and FIG. 5 is a humidity-output voltage characteristic diagram for explaining the operation. In the drawing, 1 is a fan motor, 2 is an ultrasonic vibrator, and 9 is L
C oscillation circuit, 13 is a variable resistor, 19 is a square wave generation circuit,
33 is a humidity sensor, 46 is a humidity detection circuit, 53 is a humidity setting circuit, 58 is an electrical difference detection circuit, and 64 is a control circuit. Applicant: Tokyo Shibaura Electric Co., Ltd. Figure 2 Figure 30 4 No. 42 41 Figure 4 Quick Talk 5 Figure e

Claims (1)

[Claims] 1. A humidity sensor that is installed to detect atmospheric humidity and whose electrical resistance value changes depending on the humidity, a humidity detection circuit that converts the electrical resistance value of this humidity sensor into voltage, and outputs the desired humidity as voltage. A humidity setting circuit that outputs a humidity setting circuit, a voltage difference detection circuit that outputs the difference in output voltage between the humidity detection circuit and the humidity setting circuit, and a humidifier output that changes the humidifier output in stages according to the output voltage of this voltage difference detection circuit. An automatic control device for a humidifier, comprising a control circuit.