JPH058341B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic humidifier mounted on a vehicle, and particularly has a water level detector suitable for detecting when the water level drops and water disappears. Regarding vehicle humidifiers.

[Conventional technology]

Conventional ultrasonic humidifiers have a water level detector using a float as described in Japanese Patent Publication No. 55-40056. Also, a water level detector using the conductivity of water was used, as described in Japanese Patent Publication No. 58-29152.

[Problem that the invention seeks to solve]

Since the above conventional technology uses a float switch to detect a drop in the water level, it does not detect when the water turns into ice, so it is necessary to also provide other detection means such as water temperature. There were problems with the number of components, making it difficult to downsize, and the detection method at low temperatures below 0°C for vehicles. In addition, in methods that utilize the conductivity of water between electrodes, current flows through the electrodes of the vibrator during energization, which causes the problem that the electrodes of the vibrator dissolve in the water, shortening the life of the electrodes. .

Furthermore, when a humidifier is installed in a car, the water level at the detection position momentarily drops due to vibrations of the car body while driving, instantaneous inclination, sudden acceleration, sudden deceleration, etc. At this time, it is necessary to take measures to avoid erroneously determining that there is no water and stopping the operation. Furthermore, if the water level fluctuates repeatedly and the humidifier repeatedly starts and stops as a result of this, the lifespan of the device will be shortened, so it is necessary to consider countermeasures against this.

An object of the present invention is to provide a vehicle humidifier that has a long lifespan, which has less deterioration of the electrodes of the ultrasonic vibrator, and which does not stop operating due to instantaneous drops or fluctuations in the water level caused by vibrations of the vehicle body, etc. Our goal is to provide the following.

[Means for Solving the Problems] The above purpose is to provide an atomization tank having an ultrasonic vibrator and atomizing water, a water supply device supplying water to the atomization tank, and driving the ultrasonic vibrator. An oscillation circuit, a blower that blows atomized water vapor into the vehicle interior, a water level detector that detects the water level in the atomization tank and cuts off power supply to the oscillation circuit according to the detected water level, and a water level In a vehicle humidifier comprising a level detector and a power switch that connects a power source, an auxiliary electrode provided in the atomization tank and having the same potential as the potential of the ultrasonic vibrator in contact with water; The voltage of the detection electrode installed at the water level detection position in the atomization tank and the voltage of the detection electrode that depends on the current flowing from the auxiliary electrode to the detection electrode depending on the water level is compared with the specified value, and the voltage is lower than the specified value. The water level level detector is provided with a comparison means for cutting off the power supply to the oscillation circuit when the temperature drops, and a charging/discharging circuit connected to a terminal for inputting the voltage of the auxiliary electrode to the comparison means, and the output of the comparison means This is achieved by providing a holding circuit that continues the cutoff state until the power switch is turned off when the power supply to the oscillation circuit is cut off.

[Effect]

In the above vehicle humidifier, when the water level in the atomization tank is higher than the water level detection position of the detection electrode of the water level detector, there is conductivity between the auxiliary electrode and the detection electrode; When the water level becomes lower, the conductivity disappears, so the output voltage of the detection electrode changes depending on the water level. Therefore, when the voltage of the detection electrode exceeds a certain specified value, it is assumed that the water level is present, and when it falls below the specified value, the water level detection circuit detects that the water level has decreased, thereby driving the vibrator. The power to the oscillation circuit can be cut off quickly. In this way, even when water turns into ice, it will no longer be conductive, so the same detection operation as when the water level has dropped can be performed to immediately cut off the power to the vibrator's oscillation circuit. Moreover, since the current due to the conductivity of water flows from the auxiliary electrode to the detection electrode, the electrodes of the vibrator that are in contact with water are not immersed and damaged.

In addition, if the water level drops momentarily due to vehicle body vibration, etc., and the voltage of the detection electrode drops momentarily,
Since the accumulated charge in the charge/discharge circuit compensates for this instantaneous drop in voltage, the comparison means continues to supply power to the oscillation circuit and the humidifier does not stop its operation. If the water level does not drop instantaneously, the discharge of the accumulated charge in the charging/discharging circuit progresses and the voltage value cannot be maintained above the specified value, so the humidifier stops its operation.

Furthermore, if the water level fluctuates repeatedly, the holding circuit maintains this state at the first stop of operation, so there is no repeat of operation/stop, and the life of the equipment is extended.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram showing an embodiment of a vehicle humidifier according to the present invention. In Figure 1, water dispenser 1
has a valve 2 and supplies water to the atomization tank 4 having an ultrasonic vibrator 3 so as to keep the water level constant. The electrode 5 of the vibrator 3 is connected to the (+) wire 7 of the battery 6, and an oscillation circuit (clap circuit) consisting of capacitors C ₀ , C ₁ , C ₂ , inductances L ₁ , L ₂ , transistor TR ₁ and resistor R ₁ is connected. ) 8 causes the vibrator 3 to generate ultrasonic vibrations, which causes the atomization tank 4 to
water 9 is atomized. The variable resistor R ₁ of the oscillation circuit 8 adjusts the electrical energy to the vibrator 3 and the acoustic energy of the vibrator 3 to adjust the amount of atomization.

The blower motor 10 is connected to a series resistor _R2 ,
The water vapor atomized in the atomization tank 4 is blown into the vehicle interior. Series resistor _R2 prevents blower motor 10 from burning out when mechanically locked. From the (-) wire 11 of the battery 6 to the power switch 12
is used as the (-) potential line A14 of the water level detection circuit 13, etc., which detects that the water level of the atomization tank 4 has decreased. Further, the (-) electric wire 11 of the battery 6 is connected to the normally open contact 16 of the relay 15, and is used as the (-) potential line B18 of the oscillation circuit 8 and the blower motor 10. A transistor TR ₂ is connected to the coil 17 of the relay 15 and together with the relay 15 constitutes a power supply intermittent circuit.

Connect the (-) electric wire 7 of the battery 6 to the auxiliary electrode 19 installed in the water of the atomization tank 4, and connect the auxiliary electrode 19
has the same potential as the electrode 5 of the vibrator 3 that is in contact with water. The detection electrode 20 is installed substantially horizontally at a position to detect the water level of the water 9, and the detection voltage of the detection electrode 20 is input to the water level detection circuit 13. For the detection electrode 20, the auxiliary electrode 19, and the electrode 5, a material having a decreasing tendency to ionize water, such as aluminum or nickel copper, is used in this order. With this configuration, when the power is turned on, a current flows from the auxiliary electrode 19 to the detection electrode 20 in the water 9 of the atomization tank 4, and a small amount of current flows from the auxiliary electrode 19 to the electrode 5; This means that the electrodes 19 undergo electrolytic corrosion, and therefore the electrodes 5 of the vibrator 3 are rarely corroded by electrolytic corrosion.

In the above configuration, when the power switch 12 is now closed, the water level detection circuit 13 is activated, and the normally open contact 16 is closed by energizing the coil 17 of the relay 15, which forms the power cutoff circuit, through the transistor _TR2 . Afterwards, the oscillation circuit 8 is operated.
Since the normal vibrator 3 is a sintered product, it will break if over-excited, so if it is operated in a place where there is no water 9 in the atomization tank 4, for example, it will break, so the amount of water 9 will decrease and become dangerous. Vibrator 3 below the water level
It is necessary to stop the operation of the oscillation circuit 8 in order to stop supplying electrical energy to the oscillation circuit 8.

Therefore, the detection electrode 20 provided at the water level detection position of the water 9 in the atomization tank 4 detects the detection voltage corresponding to the current flowing from the auxiliary electrode 19 to the detection electrode 20 according to the water level of the water 9 to the water level detection circuit. 1
3, and as a result, when the voltage of the detection electrode 20 becomes lower than a certain specified voltage, it is detected that the water level has decreased, and the relay 15 of the water level detection circuit 13 immediately shuts off the power to the oscillation circuit 8. or apply power again when the water level recovers.

Thus, the (-) wire 11 of the battery 6 is connected and disconnected by the power switch 12 and the relay 15 of the water level detection circuit 13, and the power switch 1
2, the normally open contact 16 of the relay 15 is also opened, so that the current from the battery 6 is completely cut off. Therefore, when the power switch 12 is turned off, the current from the auxiliary electrode 19 of the atomization tank 4 to the detection electrode 20 is also cut off, so electrolytic corrosion of the auxiliary electrode 19 occurs only when the power switch 12 is turned on. ,
The auxiliary electrode 19 is less immersed.

FIG. 2 is a circuit diagram of a water level detection circuit and an alarm display circuit. In Figure 2, the first
The same reference numerals as in the figures indicate the same or corresponding parts. A constant voltage circuit 21 that generates a constant voltage is connected to the (+) electric wire 7 of the battery 6, and a constant voltage line 24 from the constant voltage circuit 21 is used as a power source for each control. The water level detection circuit 13 is connected to a resistance from the detection electrode 20 of the atomization tank 4.
Connect to the non-inverting input terminal of the operational amplifier OPA1 via _R3 , and connect the non-inverting input terminal to the (-) potential line A14.
A capacitor _C3 and a resistor _R4 are connected in parallel between the capacitor _C3 and the resistor _R4 (a charging/discharging circuit is formed with the capacitor C3 and the resistor R4), and a resistor _R7 is connected between the non-inverting input terminal and the output terminal.
are connected, and the resistors R ₅ and R ₆ are connected from the inverting input terminal to the constant voltage line 24 and the (-) potential line 14, respectively.
Also, the transistor is connected from the output terminal through resistor _R8 .
Connected to the base of TR ₂ , connected from the collector of transistor TR ₂ to the (+) electric wire 7 via the coil 17 of the relay 15 (Fig. 1), and the emitter of the transistor TR ₂ connected to the (-) potential line 14. do.

Operational amplifier OPA1 of water level detection circuit 13
and resistors R ₃ to _{R 7} constitute a Schmitt circuit,
Resistors R ₃ and R ₄ divide the input voltage from the detection electrode 20 of the atomization tank 4, and distinguish between the detection voltage when the water level drops and rises, and the voltage when the water 9 turns into ice. Schmitt circuit voltage divider resistor
This is for matching with the comparison voltage by R ₅ and R ₆ , and the capacitor C ₃ prevents detection of a momentary drop in the detection voltage due to fluctuations in the water surface due to vehicle vibration.

The alarm display circuit 22 connects resistors R ₁₀ and R ₁₁ from the non-inverting input terminal of the operational amplifier OPA2 to the constant voltage line 24 and (-) potential line 14, respectively, and connects the resistor R ₉ and capacitor C ₄ from the inverting input terminal to the constant voltage line 24 and the (-) potential line 14, respectively. It is connected to the constant voltage line 24 and the (-) potential line 14, and connected to the collector of the transistor TR ₂ of the water level detection circuit 13 with a resistor R ₁₂ and a diode D ₁ connected in series from the inverting input terminal. Also, the light emitting diode is connected to the output terminal.
Connect the LED and resistor ₁₃ in series to the constant voltage line 24, and connect the diode D ₂ and resistor in the opposite direction from the output terminal.
It is connected to the non-inverting input terminal side of the operational amplifier OPA1 of the water level detection circuit 13 via the holding circuit 23 in which _R14 is connected in series.

Operational amplifier OPA2 and resistor of alarm display circuit 22
R ₁₀ and R ₁₁ constitute a comparison circuit, the resistor 9 is a resistor for charging the capacitor C ₄ , and the series circuit of the resistor R ₁₂ and the diode D ₁ is a circuit for discharging the capacitor C ₄ .

Next, FIG. 3 is an operational characteristic diagram of FIG. 2. In the configuration shown in FIG. 2, when the power switch 12 is first closed and the water level of the water 9 in the atomization tank 4 is normal, the detection voltage of the detection electrode 20 is higher than a certain specified voltage, so the water level detection circuit 13 Since the voltage at the non-inverting input terminal of the operational amplifier OPA1 forming the Schmitt circuit becomes higher than the comparison voltage at the inverting input terminal, its output causes the transistor _{TR2 to}
When turned on, the normally open contact 16 of the relay 15 (FIG. 1) closes, energizing the oscillation circuit 8 and the blower motor 10, and operating them. When the transistor TR ₂ is turned on, the capacitor C 4 of the alarm display circuit 22 is discharged through the circuit of the resistor R ₁₂ and the diode D ₁ , and due to the small resistance value of the resistor R 12, the capacitor C ₄ of the alarm display circuit ₂₂ is discharged.
Since the potential is close to OV, the output of the operational amplifier OPA2 forming the comparator circuit becomes H level, and the light emitting diode LED remains off.

Next, when the water level drops and the detection voltage of the detection electrode 20 becomes lower than the specified voltage, the transistor TR2 of the output of the operational amplifier OPA1 of the water level detection circuit 13 turns OFF, so the normally open contact 16 of the relay 15 opens. The operation of the oscillation circuit 8 and the blower motor 10 is then stopped. Also, alarm display circuit 2
The capacitor _C4 of No. 2 is charged from the constant voltage line 24 through the resistor _R9 , and finally when the output of the operational amplifier OPA2 becomes L level, the light emitting diode LED
lights up to alert the driver.

Here, the detection delay time of the water level detection circuit 13 is
The relationship TD ₁ < TD ₂ is maintained between TD ₁ and the display delay time TD ₂ of the alarm display circuit 22. As a result, as shown in FIG. 3, during the detection delay time TD ₁ of the water level detection circuit 13 when the power switch 12 is turned on, that is, the delay time TD ₁ when the relay 15 is turned on, the light emitting diode LED of the alarm display circuit 22 is activated. does not light up and give an alarm.

In addition, the output of the operational amplifier OPA2 of the alarm display circuit 22 and the capacitor _C3 of the water level detection circuit 13
Once the light emitting diodes of the alarm display circuit 22 are turned on at once, they can be held until the power switch 12 is turned off by a holding circuit 23 having a diode D ₂ and a resistor R ₁₄ connected in series between them. As a result, once the relay 15 is disconnected and the operation of the vibrator 3 is stopped, the water that has been blown up onto the atomization tank 4 falls down, causing the water level to rise again.
Next, the water level is determined to be normal and the operation of starting the drive of the vibrator 3 is repeated, and then it is completely stopped. At this time, the operation of the relay 15 increases, resulting in a shortened lifespan, as shown in Figure 3. The defects shown by the solid line can be eliminated as shown by the broken line.

〔Effect of the invention〕

According to the present invention, the water level can be detected by the current flowing between the auxiliary electrode and the detection electrode of the atomization tank, so there is no need to take into account when the water freezes, and it can be made smaller. This has the effect of extending the life of the vibrator without immersing its electrodes.

In addition, even if the water level at the detection position momentarily drops due to vehicle vibration, etc., this will not be mistakenly detected as no water, and even if the water level repeatedly fluctuates, the humidifier will operate in response. / No repeated stops.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of a vehicle humidifier according to the present invention, FIG. 2 is a circuit diagram of a water level detection circuit and an alarm display circuit, and FIG. 3 is an operating characteristic diagram of FIG. 2. . 1... Water supply device, 2... Valve, 3... Vibrator,
4... Atomization tank, 5... Vibrator electrode, 6... Battery, 7... (+) electric wire, 8... Oscillation circuit, 9...
...Water, 10...Blower motor, 11...
(-) Electric wire, 12... Power switch, 13... Water level detection circuit, 14... (-) Potential line A, 1
5...Relay (power supply intermittent circuit), 16...Relay normally open contact, 17...Relay coil, 18...
(-) Potential line B, 19... Auxiliary electrode, 20... Detection electrode, 21... Constant voltage circuit, 22... Alarm display circuit, 23... Holding circuit, 24... Constant voltage line,
_R1 to _R14 ...Resistor, _C0 to _C4 ...Capacitor, _L1 ,
_L2 ...Inductance, _TR1 ~ _TR2 ...Transistor, LED...Light emitting diode, _D1 ~ _D2 ...Diode.

Claims (1)

[Claims] 1. An atomization tank that has an ultrasonic vibrator and atomizes water;
A water supply device that supplies water to the atomization tank, an oscillation circuit that drives an ultrasonic vibrator, a blower that blows atomized water vapor into the vehicle interior, and a water level that detects the water level of the atomization tank. In a vehicle humidifier that consists of a water level detector that cuts off the power supply to the oscillation circuit depending on the Compare the voltage of the auxiliary electrode and the detection electrode installed at the water level detection position in the atomization tank with the specified value, which depends on the current flowing from the auxiliary electrode to the detection electrode according to the water level. The water level detector is provided with a comparison means for cutting off power supply to the oscillation circuit when the voltage becomes less than a specified value, and a charging/discharging circuit connected to a terminal for inputting the voltage of the auxiliary electrode to the comparison means; A humidifier for a vehicle, characterized in that a holding circuit is provided that maintains a cut-off state when power supply to the oscillation circuit is cut off by the output of the comparison means.