JPS6051008B2 - Ultrasonic humidifier protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a protection device for an ultrasonic humidifier that prevents the atomization vibrator that generates ultrasonic waves from being destroyed due to emptying or deterioration of heat dissipation.

As is well known, ultrasonic humidifiers are constructed by placing an atomizing vibrator that generates ultrasonic waves in a water tank, but when used for a long period of time, more water scale accumulates on the surface of the vibrator than on other parts. If this phenomenon is recognized as a fact and causes this accumulation,
Vibrators that have been cooled by water may suffer from poor heat dissipation and may be destroyed.

Furthermore, if the vibrator is left in a so-called empty state due to bubbles adhering to the surface of the vibrator or the water in the tank running out, there is a risk that the vibrator will be destroyed as well. The present invention has been made to eliminate the above-mentioned drawbacks, and its first purpose is to detect the load current that depends on the vibrator current, and use the detection output to suppress the increase in the vibrator current. The second purpose is to reduce the oscillator current to an extremely small value or cut it off to ensure reliable protection when the oscillator current cannot be protected by suppressing the oscillator current. To provide protection device for ultrasonic humidifier.

Embodiments of the present invention will be described below with reference to the drawings. 1st
6 to 6 show embodiments that achieve the first object of the present invention, and common parts in each figure are designated by the same reference numerals. In the first embodiment shown in FIG. 1, reference numerals 1 and 2 are AC power supply terminals, which are connected to an AC input terminal of a full-wave rectifier circuit 4 with a power switch 3 interposed between them. This full-wave rectifier circuit 4 is composed of diodes 5 to 8, a smoothing capacitor 9 is connected between the DC output terminals, and one DC bus is connected to one DC output terminal via a choke coil 10 for cutting off high frequencies. 11, and the other DC bus bar 12 is connected to the other DC output terminal. 13 is an oscillation transistor whose collector is connected to one DC bus 11
The emitter is connected to the DC bus 12 through a parallel circuit of a resistor 14 and a capacitor 15.

The oscillation transistor 13 is connected to an oscillation capacitor 16,
17 and the equivalent inductance of the atomizing vibrator 18 constitute a self-excited Colpitts type oscillation circuit 19. For this purpose, one oscillation capacitor 16 is connected between the DC buses 11 and 12. , the other oscillation capacitor 17 is connected to the base of the oscillation transistor 13 and the DC bus 12.
is connected between. 20 is an oscillation transistor 13
and the vibrator 18, one end of its primary winding 21 is connected to the DC bus 11, the other end 21a is connected to the base of the oscillation transistor 13 via the coupling capacitor 22, and the output transformer output transformer 20
It is connected to the secondary winding 23 of.

Reference numeral 24 denotes a current detection circuit for detecting the current of the vibrator 18, that is, the load current depending on the vibrator current, and one end of the detection capacitor 25 in this current detection circuit 24 is connected to receive input from the primary winding 21. The other end of the detection capacitor 25 is connected to the DC bus 12 via a diode 26 with a direction opposite to the DC power supply voltage, and a half-wave rectifier diode 27 is connected in parallel to the diode 26. A series circuit of a smoothing capacitor 8 and a smoothing capacitor 8 are connected, and a potentiometer 9 is connected in parallel with the smoothing capacitor 28.

The sliding terminal of this potentiometer 29 is connected to the current suppression circuit 3.
0 through a resistor 32, and a parallel circuit of a capacitor 33 and a resistor 34 is connected between the base and the DC bus 12. The current suppression circuit 30 is for suppressing an increase in the vibrator current in response to the detection output from the current detection circuit 24, and includes a bias control transistor 35 connected to the transistor 31 in Darlington, and,
The emitter of one transistor 31 is connected to the DC bus 12 via a resistor 36, the collector of the transistor 35 is connected to the base of the oscillation transistor 13 via a resistor 37, and this base is connected to the DC bus via a resistor 38. Connected to 11. Next, the operation of the above configuration will be explained.

Now, when the power switch 3 is turned on and AC power is applied to the full-wave rectifier circuit 4, DC power is applied between the DC buses 11 and 12, and therefore the oscillation transistor 13, the oscillation capacitors 16 and 17, and the vibration The Colpitts-type oscillation circuit 19, whose basic configuration is the equivalent inductance of the child 18, starts oscillating, and its frequency is controlled by the oscillation capacitors 16 and 17.
depends on the equivalent inductance of the resonator 18, and furthermore, the amplitude of the resonator current, and therefore the current value, is determined by the equivalent resistance and resistance of the current suppression circuit 30 seen from between the base of the oscillation transistor 13 and the DC bus 12. The value depends on the base bias voltage of the oscillation transistor 13 determined by the voltage division ratio with 38. As described above, the vibrator 18 is driven by the oscillation circuit 19, emits ultrasonic waves to the water in the water tank, atomizes the ultrasonic waves, and humidifies the room. Now, in the above operating state, a part of the load current that depends on the vibrator current passing through the primary winding 21 of the output transformer 20 flows into the current detection circuit 24 via the detection capacitor 25, and then flows into the current detection circuit 24 through the detection capacitor 25. Since the current is converted to DC by the smoothing capacitor 28, a DC voltage depending on the vibrator current is generated in the potentiometer 29 as a detection output, and this is applied to the resistor 3.
2 to one transistor 3 in the current suppression circuit 30
1 and determines the value of the collector current of the other transistor 35. Therefore, water scale may accumulate on the surface of the vibrator 18, or bubbles may adhere to the surface of the vibrator 18, or the water tank may become empty due to lack of water.
When the resonator current increases, the voltage between the terminals of the potentiometer 29 also increases, and the collector current of the transistor 35 decreases. Therefore, the oscillation transistor 13 is base biased in the direction in which its base voltage approaches the potential of the DC bus 12. The voltage is reduced and the increase in vibrator current is suppressed. In this way, destruction of the vibrator 18 due to excessive current is prevented. In the second embodiment shown in FIG. 2, the current detection circuit 24 includes a low impedance detection transformer 39, whose primary winding 40 is connected in series with the primary winding 21 of the output transformer 20, and whose secondary winding A resistor 42 is connected between both ends of the resistor 41, and a series circuit of the diode 27 and the smoothing capacitor 28 is connected in parallel with the resistor 42, and the other components are the same as in FIG.

With this configuration, the load current flowing through the primary winding 21 of the output transformer 20 is detected by the detection transformer 39, and the same effect as described above can be obtained. The third embodiment shown in FIG. 3 has a secondary winding 4 in the current detection circuit 24.
Detection transformer 44 with 3 connected in the same way as in Fig. 2
By connecting the primary winding 45 and the vibrator 18 in series, the current detection circuit 24 is configured to directly detect the vibrator current via the detection transformer 44, and the detected current is connected to the output transformer 20. It is possible to prevent the influence of leakage impedance. The fourth embodiment shown in FIG. A configuration in which a resistor 42 similar to that shown in FIG. 3 is connected to the winding 46 and the load current is detected through the tertiary winding 46 has the advantage that only one transformer is required. The fifth embodiment shown in FIG. 5 has the detection capacitor 25 and diode 26 in FIG.
By removing the diode 27 and connecting the anode of the diode 27 to the emitter of the oscillation transistor 13, the voltage drop across the emitter resistor 14a is used as a detection input. FIG. 6 shows a sixth embodiment of the present invention in which the oscillation circuit is of a separately excited type, and this will be described in detail below.

That is, 48 is a Colpitts oscillation circuit configured as is well known, which includes an oscillation transistor 13, oscillation capacitors 49 and 50, an oscillation coil 51, and resistors 52 to 55.
It consists of: 56 is an output transistor whose collector is connected to the DC bus 11 through a choke coil 57, whose emitter is connected to the DC bus 12 through a parallel circuit of a resistor 58 and a capacitor 59, and whose collector is connected to the DC bus 12 through a parallel circuit of a resistor 58 and a capacitor 59; It is connected to the DC bus 12 via the vibrator 18 .

In addition, the input side end of the detection capacitor 25 similar to that shown in FIG. It is connected to the base of the output transistor 56 via a . According to the configuration shown in FIG. 6, the oscillation output of the Colpitts oscillation circuit 48 is amplified by the output transistor 56 and drives the vibrator 18. In this case, the resonator current is detected by the current detection circuit 24 using the voltage across the resonator 18, and the base bias voltage of the output transistor 56 is controlled by controlling the collector current of the transistor 35 of the current suppression circuit 30. However, there is a method to suppress the increase in the vibrator current. Next, embodiments for achieving other objects of the present invention will be described.

That is, the seventh embodiment shown in FIG. 7 basically has a configuration in which a stop circuit 63 having a display circuit 62 is added to the circuit shown in FIG. 1, and the stop circuit 63 is a current suppression circuit. 64
The vibration occurs in response to the fact that the amount of vibrator current suppression has reached a predetermined value. The display circuit 62 is designed to minimize or cut off the motor current, and the display circuit 62 is a stop circuit 6.
This is intended to display the operating status of the stop circuit 63, such as the stop circuit 63 according to No. 3. The current suppression circuit 64 in FIG.
The configuration of is slightly different from that of FIG. 1, in that the emitter of the first stage transistor 65, which corresponds to the transistor 31 in FIG. Connect the emitter to the common line 67 and connect the collector to the resistor 6
8 and a capacitor 69 in parallel circuit to the DC bus 12.
Connect to. The stop circuit 63 has a thyristor 70 connected in the forward direction between the common line 67 and the DC bus 12, the gate of which is connected to the DC bus 12 via a resistor 71, and a constant voltage conducting element 72 such as a Zener diode. to the collector of transistor 66 through. Further, the resistor 38 is connected between the common line 67 and the DC bus 11, and a capacitor 7 is connected between the common line 67 and the DC bus 12.
At the same time, the common line 67 is connected to the base of the oscillation transistor 13 via a resistor 74. The display circuit 62 has a collector connected to a display lamp 7 made of a neon lamp.
A transistor 76 connected to the DC bus 12 through 5
Its base is connected to the common line 67 through a resistor 77, its emitter is connected to the DC bus 12 through a resistor 78, and its collector is connected to the DC bus 11 through a resistor 79. The operation of the embodiment of FIG. 7 with the above configuration will be described. (1) When the load current detection input is received at the base of the transistor 65 of the current suppression circuit 64, if this is in the increasing direction,
Since the collector voltage of the transistor 65 drops, the emitter voltage of the other transistor 66 and hence the voltage of the common line 67 drop, and the base bias voltage of the oscillation transistor 13 is reduced, so an increase in the resonator current is suppressed. . During such a vibrator current suppression action, if the vibrator 18 reaches an abnormal state that further increases its vibrator current, that is, the vibrator 18 is not protected by the vibrator current suppression action by the current suppression circuit 64. When you reach a state where you can't do it anymore,
At this time, the resonator current is about to become extremely large, and the collector current of the transistor 66 is increasing due to the increase in the amount of suppression associated with this, so the terminal voltage of the resistor 68 becomes higher than the cutoff voltage of the constant voltage conduction element 72. The constant voltage conduction element 72 becomes conductive, and the thyristor 7
0 turns on upon receiving the gate signal. For this reason, the common line 6
7 decreases to approximately the potential of the DC bus 12, the base bias voltage of the oscillation transistor 13 becomes extremely low, the resonator current becomes extremely small or is cut off, and the resonator 18 The drive is substantially stopped and protected from destruction. At the same time, as the potential of the common line 67 drops, the transistor 76 that has been in the on state turns off, so the indicator lamp 75 lights up, indicating that the stop circuit 63 has been activated, that is, the oscillator 18 Notifies that the drive has been stopped due to a protective effect. This allows the user to know whether it is necessary to clean the vibrator 18 or replenish water. According to this embodiment, since the thyristor 70 automatically continues in this state until the power is cut off after being turned on, a self-holding circuit is not required and the configuration is simplified. Furthermore, since it is determined by the constant voltage conduction element 72 provided in the gate circuit of the thyristor 70 that the amount of suppression of the vibrator current by the current suppression circuit 64 has reached a predetermined value, variations in the start of operation of the thyristor 70 are prevented. This can be prevented from occurring. In the eighth embodiment shown in FIG.
In place of the thyristor 70, a first transistor 80 and a second transistor 81 are connected to form a thyristor equivalent circuit. A suppressing transistor 82 is provided, and its collector is connected to the common line 6.
7, and its emitter is connected to the DC bus 12 via a voltage-bearing resistor 83, and furthermore, the emitter of the first transistor 80 is connected to the common line 67, and the emitter and base of the second transistor 81 are connected to the common line 67. are connected to the DC bus 12 and the emitter of a current suppressing transistor 82, respectively, and the collector of the transistor 81 is connected to the common line 67 via a resistor 84, and the other configuration is the same as that in FIG.

According to the eighth embodiment, the first and second transistors 80 and 81 do not take the place of the thyristor 70, but also function as the transistor 66 in FIG. 7, making the structure inexpensive. In the ninth embodiment shown in FIG. 9, another thyristor 85 is provided in place of the thyristor 70 in FIG.
The anode of this thyristor 85 is connected to the positive DC output terminal of the full-wave rectifier circuit 4 through a relay coil 86 of a relay corresponding to a switch device, while the positive DC output terminal and the DC bus 11 are connected to each other. A fixed contact piece a interposed between contact pieces cmd on the normally closed side of the relay contact 87 and between contact pieces cma on the normally open side is connected to the DC bus 12 via a resistor 88 and an indicator lamp 75.

In this ninth embodiment, when the thyristor 85 is turned on by the same action as in the case of FIG.
At the same time, the contact between the contact pieces CMB is turned off to cut off the DC power supply of the oscillation circuit 19, and at the same time, the contact between the contact pieces CMA is turned on and the indicator lamp 7 is turned on.
5 is lit. Incidentally, as a modification of this ninth embodiment,
Although not shown, a relay contact may be provided in series with the vibrator 18 to directly cut off the vibrator current. In the tenth embodiment shown in FIG. 10, instead of the thyristor 70 which receives input through the constant voltage conduction element 72 in FIG. A stable multivibrator 90 is provided, and this monostable multivibrator 90 consists of two transistors 91 and 92, a capacitor 93, and resistors 94 to 96, and only one transistor 91 is always on. . In this embodiment as well, as in the case of FIG. 7, when the amount of suppression of the vibrator current by the current suppression circuit 64 reaches a predetermined value, the constant voltage conduction element 72 becomes conductive. The transistor 91 on the source side is turned off and the other transistor 92 is turned on. By turning on this transistor 92, the oscillation transistor 13 is substantially cut off and oscillation is stopped. If the vibrator current of the vibrator 18 recovers to a normal value, the constant voltage conduction element 72 is cut off at this point, so the monostable multivibrator 90
also returns to its original state, and the oscillation circuit 19 recovers its oscillation state. As described above, even if the vibrator becomes dry or suffers from poor heat dissipation, the present invention prevents the vibrator from being destroyed by suppressing the accompanying increase in vibrator current. The present invention provides a protection device for an ultrasonic humidifier that ensures reliable protection by extremely reducing or cutting off the vibrator current when protection cannot be achieved by the suppressing action.

[Brief explanation of the drawing]

1 to 10 are wiring diagrams showing first to tenth embodiments of the present invention, respectively. In the figure, 13 is an oscillation transistor, 14a is a transmitter resistor, 16 and 17 are oscillation capacitors, 18 is a vibrator,
19 is an oscillation circuit, 20 is an output transformer, 21 is a primary winding, 23 is a secondary winding, 24 is a current detection circuit, 25 is a detection capacitor, 30 is a current suppression circuit, 35 is a transistor for bias control, 39 , 44 is a detection transformer, 46
is a tertiary winding, 47 is an output transformer, 48 is a Colpitts oscillation circuit, 56 is an output transistor, 62 is a display circuit, 6
3 is a stop circuit, 64 is a current suppression circuit, 70 is a thyristor, 72 is a constant voltage conduction element, 75 is an indicator lamp, 80 is a first transistor, 81 is a second transistor, 82 is a current suppression transistor, 83 is a Voltage burden resistor, 86
is a relay coil (switch device), 87 is a relay contact (
switch device).

Claims (1)

[Claims] 1. An oscillation circuit including an oscillation transistor that drives an atomizing vibrator, a current detection circuit that detects a load current that depends on the vibrator current, and a detection output from this current detection circuit. A protection device for an ultrasonic humidifier, comprising: a current suppression circuit that receives as an input and suppresses an increase in the vibrator current. 2. A patent in which the oscillation circuit is configured in a self-excited type in which an oscillation transistor and a resonator are coupled via an output transformer, and the current detection circuit is configured to receive input from the primary winding of the output transistor via a detection capacitor. A protection device for an ultrasonic humidifier according to claim 1. 3. The oscillation circuit is configured in a self-excited type in which an oscillation transistor and a resonator are coupled via an output transformer, and the current detection circuit has a detection transformer connected in series to the primary winding of the output transformer. The ultrasonic humidifier protection device according to claim 1, wherein the ultrasonic humidifier protection device is configured to receive input via a transformer. 4. The ultrasonic humidifier according to claim 1, wherein the current detection circuit has a detection transformer connected in series with the vibrator, and is configured to detect the vibrator current via the detection transformer. Protective device for equipment. 5. The oscillation circuit is configured in a self-excited type in which an oscillation transistor and a resonator are coupled through the primary and secondary windings of the output transformer, and the current detection circuit is configured to receive input from the tertiary winding of the output transformer. A protection device for an ultrasonic humidifier according to claim 1. 6. The ultrasonic humidifier protection device according to claim 1, wherein the current detection circuit is configured to detect a voltage drop across an emitter resistance of an oscillation transistor. 7 Colpitts oscillation circuit, an output transistor that receives the oscillation output from this oscillation circuit as input, an atomization oscillator driven by this output transistor, and a current that detects a load current that depends on the oscillator current. a detection circuit;
A protection device for an ultrasonic humidifier, comprising a bias control transistor that receives the detection output from the current detection circuit as an input and controls the base bias voltage of the output transistor in a direction that suppresses an increase in the vibrator current. 8. An oscillation circuit including an oscillation transistor that drives an atomizing vibrator, a current detection circuit that detects a load current that depends on the vibrator current, and a current detection circuit that receives the detection output from this current detection circuit as input and drives the vibrator. a current suppression circuit that suppresses an increase in current; and a stop circuit that reduces the vibrator current to an extremely small value or cuts it off in response to the amount of current suppression caused by the current suppression circuit reaching a predetermined value. A protection device for an ultrasonic humidifier, comprising: 9. The protection device for an ultrasonic humidifier according to claim 8, wherein the stop circuit has a display circuit that displays its operating status. 10. The device according to claim 8, wherein the stop circuit includes a thyristor that receives a gate signal from the current suppression circuit, and is configured to reduce the vibrator current to an extremely small value or cut it off by switching the thyristor. Ultrasonic humidifier protection device. 11. The ultrasonic humidifier protection device according to claim 10, wherein the gate of the thyristor has a constant voltage conducting element connected in series. 12 The current suppressing circuit is constituted by a current suppressing transistor having a voltage burdening resistor in series between the collector and the emitter, and the stop circuit is composed of a first transistor that receives base input from the terminal voltage of the voltage burdening resistor and this transistor. 9. The ultrasonic humidifier protection device according to claim 8, comprising a first transistor and a second transistor connected together to form a thyristor equivalent circuit. 13. The ultrasonic humidifier protection device according to claim 8, wherein the stop circuit includes a switch device that cuts off power to the oscillation circuit. 14. Claim 9, wherein the stop circuit includes a relay that is energized when the current suppression amount reaches a predetermined value, and a relay contact that cuts off the power to the oscillation circuit and energizes the display circuit. Ultrasonic humidifier protection device described. 15. The ultrasonic humidifier protection device according to claim 8, wherein the stop circuit is configured to control the base bias voltage of a transistor in an oscillation circuit that can control the vibrator current.