JPH06229961A - Liquid detection device - Google Patents

Abstract

PURPOSE:To provide a liquid detection device which can use a normal electrode while preventing corrosion of the electrode due to electrolysis as much as possible. CONSTITUTION:The title device for detecting the presence or absence and characteristics of a liquid based on the resistance between electrodes 11b and 11c by applying a specific voltage to a pair of electrodes 11b and 11c using a voltage-application means is provided with a means for controlling application time for controlling the output time of a voltage application means quickly, thus reducing the time for electrolysis within the liquid, preventing progress of corrosion of an electrode, and eliminate the need for using conventional expensive platinum-plated electrodes 11b and 11c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid detecting device for detecting the presence or absence of liquid or the characteristics of liquid by means of electric resistance.

[0002]

2. Description of the Related Art Conventionally, as a liquid detecting device of this type, a predetermined voltage is applied to a pair of electrodes immersed in a liquid, and the resistance value of the liquid obtained between the electrodes is compared with a reference resistance value. It is generally known that the characteristics of the liquid are detected from the comparison signal.

[0003]

As described above, in the liquid detection device, each electrode is immersed in the liquid, and a voltage is applied to the electrode, so that electrolysis occurs in the liquid, and the electrode on the anode side is accompanied by the electrolysis. There is a risk that the electrode may be corroded due to the oxidation effect. Therefore, when a DC voltage is applied, platinum for corrosion prevention must be plated as the electrode on the anode side, which results in a high cost. On the other hand, in order to prevent the corrosion of this electrode, a means for applying an AC voltage has been proposed, but an AC oscillation circuit or the like is separately required to apply the AC voltage, and the cost increase cannot be avoided. .

Further, when the voltage is continuously applied to the electrodes for a long time, the characteristics of the liquid are deteriorated by the electrolysis, hydrogen is further generated on the cathode side, and the electric resistance is gradually increased. There was a problem that the accuracy became unstable.

In view of the above conventional problems, an object of the present invention is to
It is an object of the present invention to provide a liquid detection device which can use normal electrodes while preventing corrosion of electrodes due to electrolysis as much as possible and which improves detection accuracy.

[0006]

In order to solve the above-mentioned problems, the present invention provides a liquid crystal according to claim 1 in which a predetermined voltage is applied to a pair of electrodes by a voltage applying means, and a resistance value between the electrodes is applied. In a liquid detection device that detects the presence or absence of
It is characterized by further comprising application time control means for controlling the output time of the voltage application means in a short time.

According to a second aspect of the present invention, in the liquid detecting apparatus according to the first aspect of the invention, the application time control means activates the voltage application means at predetermined time intervals.

The invention of claim 3 relates to claim 1 or claim 2.
In the liquid detecting device according to the invention, there is provided a detection time control means for detecting a resistance value after a lapse of a predetermined time after the start of output in the output time of the voltage applying means.

[0009]

According to the invention of claim 1, since the output time of the voltage applying means is shortened by the applied voltage control means, the electrolysis time in the liquid is short and the corrosion of the electrodes is prevented. it can.

According to the second aspect of the invention, even when the liquid is detected for a long time, the detection time is short and the electrode corrosion can be prevented.

According to the third aspect of the invention, the voltage application means is in an unstable state due to the rush voltage and the like at the initial output, but the detection time control means detects the liquid characteristic at this unstable time. Is avoided.

[0012]

1 to 3 show an embodiment of a liquid detecting device according to the present invention. FIG. 1 shows a liquid spraying device to which the liquid detecting device is applied. The configuration of the liquid spraying device will be briefly described with reference to FIG.

That is, 1 is a vapor liquid F1 such as water or purified water.
A first tank 2 for accommodating a liquid supply pipe, 2 is a liquid supply pipe inserted in the first tank 1, 3 is an electromagnetic pump interposed in the liquid supply pipe 2, and 4 is a liquid supply pipe 2 connected to its inlet portion. The vaporizer 5 is a first nozzle connected to the tip of the vaporizer 4. here,
When driving the electromagnetic pump 3, the vapor liquid F1 in the first tank 1 is fed to the vaporizer 4, and the fed liquid F1 is heated by the high-temperature vaporizer 4 by the heater 4a.
It is turned into steam from the nozzle 5 and ejected. On the other hand, 6 is a second tank for containing the spraying liquid F2 such as deodorant liquid and disinfectant liquid,
7 is a liquid absorption pipe inserted in the second tank 6, 8 is a liquid absorption pipe 7
Is a second nozzle that is connected to the first nozzle 5 and has one end located near the tip of the first nozzle 5. Here, as described above, when the steam is ejected from the first nozzle 5, the negative pressure based on the Venturi action generated on the tip side of the second nozzle 8 causes the second tank 6 to flow.
The spraying liquid F2 therein is sucked up, collides with the vapor, atomizes, and is mixed with the vapor and sprayed. Reference numeral 9 is a liquid return pipe, and 9a is an electromagnetic valve for opening and closing the return pipe 9.

Deodorization and disinfection are performed in the room by the action of such a liquid spraying device, but when the liquids F1 and F2 contained in the first tank 1 and the second tank 6 are erroneously accommodated in reverse, that is, When the first tank 1 contains a spraying liquid F2 such as a deodorant liquid and a disinfecting liquid, and the second tank 6 contains a vapor liquid F1 such as water or purified water, the spraying liquid F2
When the water vaporizes in the vaporizer 4, the deodorant or the like contained in the spray liquid F2 adheres to the vaporizer 4, causing clogging in the vaporizer 4. Therefore, the first tank 1
It is necessary that the liquid stored in is always the liquid F1 for vapor, and in order to ensure this, the liquid detector according to the present invention detects the characteristics of the liquid in the first tank 1.

FIG. 2 is an example of an electric circuit diagram showing the structure of the liquid detector. The liquid detector 10 includes a detection voltage output circuit 11, a reference voltage output circuit 12, a comparator 13,
The detection voltage output circuit 11 and the reference voltage output circuit 12 are connected in parallel with a CPU 14 having a microcomputer configuration to a DC power source via an operation switch 15.
The comparator 13 is grounded via the transistor 16.

The detection voltage output circuit 11 comprises a resistor 11a and a pair of electrodes 11b and 11c connected in series. The electrodes 11b and 11c are immersed in the vapor liquid F1 in the first tank 1, and the liquid F1 between the electrodes 11b and 11c serves as an electric resistance.
A detection voltage corresponding to the characteristics of the liquid F1 is output from the electric resistance between the resistance and the resistance 11a. Further, the reference voltage output circuit 12 outputs a constant reference voltage from the resistors 12a and 12b connected in series.

The detection voltage and the reference voltage output from each of the output circuits 11 and 12 are input to the comparator 13, and when the reference voltage is high in the comparator 13, a high level signal is sent to the CPU 14 via the input port 14a. It is designed to be input to. The alarm buzzer 17 is controlled based on the input signal to the input port 14a.

The output circuits 11 and 12 and the comparator 13 are activated when the transistor 16 is on,
The transistor 16 serves as a voltage applying means to the electrodes 11b and 11c. Also, this transistor 16 is C
It is controlled by a control signal output via the output port 14b of the PU 14. Note that 16 a and 16 b are operating resistors of the transistor 16.

Next, the control of the CPU 14 will be described with reference to the flowchart of FIG.

It is determined whether or not the operation switch 15 is turned on (S1). When the operation switch 15 is turned on here, the output port 14b outputs to the transistor 16 2
A signal is output to turn on for a second (S2).
That is, the CPU 14 constitutes an application time control means for regulating the on time of the transistor 16 which is the voltage application means.

When the transistor 16 is thus turned on, the detection voltage output circuit 11, the reference voltage output circuit 12 and the comparator 13 are activated to detect the presence or absence of the liquid F1 contained in the first tank 1 and the characteristics thereof. .

When 1 second has elapsed from the output of the ON signal to the transistor 16, the signal (high level signal or low level signal) output from the comparator 13 is read for 1 second (S3, 4). As described above, in step 3 and step 4, only the second half of the second half of the on-time of the transistor 16 is read, and the CPU 14 is also configured as a detection time control means.

Here, when the liquid F1 is not contained in the first tank 1, or the deodorizing liquid which is an unsuitable liquid,
When the liquid is a disinfectant, a high-level signal is output from the comparator 13. When the high-level signal is input, the liquid F1 is determined to be abnormal, the alarm buzzer 17 is driven, and an alarm is issued (S5, S6). ). When the operation switch 15 is turned off based on this alarm, the alarm buzzer 17 is stopped (S7, S8).

On the other hand, when no abnormality is detected in step 5 described above, that is, when the low level signal is input to the input port 14a and it is determined that the liquid F1 is normal, the process waits for 30 minutes, and then step 2 again. The presence / absence and characteristics of the liquid F1 are detected by returning to.

As described above, in the liquid detecting device according to the present embodiment, since the time for applying to the electrodes 11b and 11c is only 2 seconds, the electrolysis which occurs in the liquid F1 to be detected becomes small, The electrodes 11b and 11c do not corrode. Therefore, it is not necessary to use expensive platinum-plated electrodes as the electrodes 11b and 11c as in the prior art, and the electrodes 11b and 11c can be formed only by a commonly used stainless steel material.

Since only the second half of the voltage application time is read as liquid detection,
It is possible to avoid reading an unstable detection voltage that is output at the beginning of voltage application, and to accurately determine the liquid characteristics.

Further, the liquid F1 in the first tank 1 is gradually reduced by the driving of the liquid spraying device, so that the liquid F1 is newly replenished in the first tank 1. In this way, the liquid F1 is replenished. Even when is intermittently performed, voltage application and liquid detection are performed every 30 minutes. For this reason, the characteristic change at the time of replenishing the liquid can be surely detected, and the continuous liquid detection can be performed. Further, as described above, since the voltage application is once for a short time, the electrode corrosion can be avoided. Of course,
Liquid deterioration due to electrolysis does not proceed.

In the above embodiment, the detection voltage output circuit 1
1, the liquid F by the reference voltage output circuit 12 and the comparator 13
Although the characteristic of No. 1 is detected, it is not limited to such a configuration. For example, although not shown, the resistance value detected by the electrode is amplified, and this is analog-digital converted and input to the microcomputer. The suitability of the liquid may be judged by comparing with the reference data stored in the microcomputer. Further, in the above-described embodiment, the detection configuration of the liquid contained in the tank of the liquid spraying device has been described, but the present invention is not limited to this, and can be applied to any one as long as the characteristic detection of the liquid is required. .

[0029]

As described above, according to the first aspect of the invention, since the output time of the voltage applying means is shortened by the applied voltage control means, the electrolysis time in the liquid is short. In addition, it is possible to prevent the corrosion of the electrodes, and it is not necessary to use expensive platinum-plated electrodes as in the prior art, so that the cost is low.

According to the second aspect of the invention, even when the liquid is detected for a long time, the application time to the electrode is short, and the corrosion of the electrode can be prevented.

According to the third aspect of the present invention, the output of the voltage applying means is in an unstable state due to its inrush voltage at the initial output, but the detection time control means avoids the detection at this unstable time. The liquid characteristics can be detected accurately.

[Brief description of drawings]

FIG. 1 is a sectional view of a liquid spraying device to which a liquid detection device according to the present invention is applied.

FIG. 2 is an electric circuit diagram of a liquid detection device according to the present invention.

FIG. 3 is a control flowchart of the CPU

[Explanation of symbols]

10 ... Liquid detection device, 11b, 11c ... Electrode, 14 ... C
PU, 16 ... Transistor, F1 ... Vapor liquid, F2 ...
Liquid for atomization.

Claims (3)

[Claims] 1. A liquid detection device for detecting a presence or absence of a liquid or a characteristic based on a resistance value between the electrodes by applying a predetermined voltage to the pair of electrodes by a voltage application unit, and shortening the output time of the voltage application unit. A liquid detection device having an application time control means for controlling the time. 2. The application time control means activates the voltage application means every predetermined time.
The liquid detection device described. 3. The method according to claim 1, further comprising a detection time control means for detecting a resistance value after a lapse of a predetermined time after the start of output of the output time of the voltage application means.
The liquid detection device described.