JPH10170498A - Sensor for dry-cleaning detergent concentration and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the measurement of concentration from both data on impedance obtained by impressing an a.c. voltage between a plurality of electrodes immersed in a cleaning liquid and data on the temperature of the cleaning liquid obtained by a temperature sensor. SOLUTION: In a concentration sensor 1, an electrode 3 is concentrically fixed in a cylindrical external electrode 2, and a temperature sensor 4 is protruded from the center of the internal electrode 3. A dry-cleaning cleaning liquid is contained between the electrodes 2 and 3, and capacitance occurs there. This capacitance is measured to obtain the concentration of a detergent from changes in capacitance. As the relation between capacitance and concentration differs according to temperature, the temperature sensor 4 is provided for measuring the temperature of the cleaning liquid to perform compensation by temperature. Any element whose resistance and electromotive force change by temperature may be used for the temperature sensor 4. The terminals at both ends of the sensor 4 are extracted to the outside by lead wires 18 and 19. A thermistor is a semiconductor temperature measuring element whose resistance decreases with the increase of temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for measuring the concentration of a detergent for dry cleaning. Dry cleaning removes dirt from clothes by refluxing a solvent in which a detergent is dissolved in a commercial dry cleaning machine. Since the cleaning ability depends on the detergent concentration, it is necessary to set the concentration at an optimum value. There are many types of detergents (soaps), and the optimum concentration differs depending on the type of the soap. It is necessary to monitor the concentration and add a detergent if it is insufficient, and add or remove a solvent if it is excessive. In order to perform such an operation, it is necessary to constantly measure the detergent concentration of the cleaning liquid. The present invention relates to a sensor for detecting a concentration of a detergent in a dry cleaning liquid.

[0002]

2. Description of the Related Art In dry cleaning, laundry and washing liquid are put in a rotating drum and rotated to remove dirt with a detergent. The cleaning liquid is injected into the drum by the pump, is discharged from below through the drum, and returns to the drum again through the filter. In other words, the same cleaning liquid recirculates the circulation system including the rotating drum many times. The detergent concentration gradually decreases because the detergent that is bound to the soil is removed by the filter. Therefore, every time the washing operation is completed, a shortage of detergent is newly added so that washing is always performed at an optimum concentration. Conventionally, the addition of the insufficient detergent has been calculated, weighed and supplied by an operator, and has not been automated.

On the other hand, Japanese Patent Publication No. Hei 7-28993 "Dry cleaner" measures the concentration of detergent at the end of the previous washing, calculates the shortage, and automatically adds the insufficient detergent. It is. The sensor has an electrode insulated from one end of a cylindrical metal container, and uses the container itself as the other electrode, and applies an alternating voltage of ± 5 V, 10 kHz between the electrodes via a fixed resistor. Since the impedance between the electrodes changes depending on the detergent concentration, the AC voltage between the electrodes changes, and the detergent concentration can be determined from the AC voltage change. Since the cleaning liquid is a mixture of a petroleum-based solvent and a detergent, it has a high insulating property and almost no DC current flows. Only alternating current flows.
As the concentration of the detergent increases, the voltage between the electrodes increases. That is, the impedance increases. The present invention is not a sensor invention, but a control system for automatically adding a detergent and automatically operating a dry cleaner.

Japanese Patent Publication No. 7-57277 also uses the same sensor. An electrode is set up on a part of the container through which the cleaning liquid passes, and the fact that the impedance between the electrodes changes depending on the detergent concentration using the container as the other electrode is used. The frequency of the alternating electric field is varied between 1 kHz and 200 kHz and the value of the voltage for different soaps is measured. He points out that the optimum frequency differs depending on the soap. Then, the current detergent concentration is compared with a predetermined optimum concentration, the shortage is calculated, and the shortage is added. Using a device in which the amount of detergent added per unit time is constant, the amount of detergent is controlled by time.

[0005]

The invention described above is an invention of a control system, not an invention of a density sensor. In the sensors using these control system exhaust gases, an electrode is set up at a corner of a container having an inlet and an outlet, a cleaning liquid is passed through the container, and an alternating current is applied between the electrodes to obtain a change in impedance. This is a combination of a container electrode and a rod-shaped electrode, and has the disadvantage that the impedance is high and the sensitivity is poor because the distance between them is wide. Since the impedance is high, it is necessary to apply a considerably high voltage AC. In addition, since the rod-shaped electrode is exposed in the container, lint waste and the like included in the laundry may wind around or adhere to the electrode. Then, the impedance changes due to lint or dust, causing a malfunction.

Further, the conventional dry cleaning detergent concentration measuring device does not take into account fluctuations due to temperature. Even though there is a proportional relationship between the detergent concentration and the alternating voltage, the relationship varies with temperature. Since it is an organic solvent, its dielectric constant changes with temperature. Naturally, the relationship between the detergent concentration and the impedance also changes depending on the temperature. With a conventional sensor, the concentration cannot be determined correctly unless the temperature is constant.

Accordingly, it is a first object of the present invention to provide a dry cleaning detergent concentration sensor in which dust, lint and the like are less likely to adhere between electrodes. It is a second object of the present invention to provide a dry cleaning detergent concentration sensor capable of accurately determining the detergent concentration even when there is temperature fluctuation.

[0008]

According to the detergent concentration sensor for dry cleaning of the present invention, an alternating voltage is applied between two electrodes immersed in a cleaning liquid to determine the impedance thereof, and the temperature sensor determines the temperature of the cleaning liquid. The detergent concentration is determined from both data.

More specifically, the inner and outer electrodes are arranged concentrically so that the cleaning liquid enters the gap between them. Since there is a dielectric between the inner and outer electrodes, the inner and outer electrodes form a capacitor. Since the capacity is proportional to the detergent concentration, the detergent concentration can be determined from the capacity. Since the temperature is also measured, the temperature can be corrected and an accurate density can be obtained.

Since an accurate temperature-corrected detergent concentration is required, the shortage is calculated, and the insufficient detergent is automatically added to the cleaning liquid tank or the pipe system.

[0011]

FIG. 1 is an assembly view of a concentration sensor according to an embodiment of the present invention. FIG. 2 is a sectional view of the same, and FIG. 3 is an exploded parts view. The concentration sensor 1 has an internal electrode 3 fixed at a concentric position inside a cylindrical external electrode 2, and a temperature sensor 4 protrudes from the center of the internal electrode 3. Since the dry cleaning solution is introduced between the external electrode 2 and the internal electrode 3, a capacitance is generated between them. The capacitance is measured, and the concentration of the detergent is obtained from the change in the capacitance. Since the relationship between the capacity and the concentration differs depending on the temperature, a temperature sensor is provided to measure the temperature of the cleaning liquid and correct the temperature. First of the present invention
Here is the feature of

The front half of an insulating insulator 5 made of a cylindrical insulator is inserted into the cavity behind the internal electrode 3 and screwed. The rear half of the insulating insulator 5 is also inserted into the cylindrical base cylinder 6 and screwed. A female screw portion 7 is cut behind the internal electrode 3.
The insulating insulator 5 has a thick middle portion and a narrow front and rear portion, and a male screw portion 8 is cut in a thin front cylindrical portion. The front male screw 8 of the insulating insulator 5 is screwed into the female screw 7 behind the internal electrode 3 to connect the two. That is, the internal electrode 3 is supported by the insulating insulator 5. The support is an insulator because it is necessary to insulate the external electrode 2 from the internal electrode 3.

A male screw portion 10 behind the insulating insulator 5
Is screwed into the female screw portion 9 of the base cylinder 6. A connection spring 11 for the internal electrode is provided between the wall in the direction perpendicular to the axis inside the internal electrode 3 and the front wall of the insulating insulator 5. This is not for applying elastic force to both, but for establishing conduction between the internal electrode 3 and the lead. The internal electrode has a cylindrical shape and uses a spring because it is difficult to screw or solder the lead inside.

The rear wall of the insulating insulator 5 and the base tube 6
An external electrode connection spring 12 extending in the axial direction is sandwiched between the vertical walls. This is not for applying elastic force, but for electrically connecting the external electrode and the lead.

Since the screws are fixed at two places, the internal electrode 3, the insulating insulator 5, and the base cylinder 6 are linearly connected. A female screw hole 13 is formed in the rear surface of the base cylinder 6.
Here, a male thread portion 15 of a straight joint 14 is screwed, and a lead wire covered with a Teflon tube 16 is connected to the straight joint 14.
Include temperature sensor lead wires 18, 19, external electrode lead wire 20, and internal electrode lead wire 21, which are surrounded by a shield wire 22, which is a mesh wire, so as to cut off the influence of external noise. ing. This is a general multi-core shielded cable 37 covered with a tube 16.

An O-ring 23 is sandwiched between the front of the insulating insulator 5 and the rear surface of the internal electrode 3. An O-ring 24 is also inserted between the rear surface of the insulating insulator 5 and the front surface of the base tube 6. In any case, it is to prevent the cleaning liquid from passing therethrough and to protect the internal space from the cleaning liquid.

That is, there are four screwing points. Internal electrode 3
And the temperature sensor 4; the female screw 7 of the internal electrode 3 and the male screw 8 of the insulating insulator 5; the male screw 10 of the insulating insulator 5 and the female screw 9 of the external electrode 2; Female threaded hole 13 of base cylinder 6 and male threaded part 15 of straight joint 14
Is screwed. The screw point of the internal electrode 3 and the screw point of the temperature sensor 4 and the screw point of the base tube 6 and the straight joint 14 are all subjected to fading so that the cleaning liquid does not pass through. The other two screw points have O-rings 23 and 24 to ensure the sealing performance. Therefore, the cleaning liquid does not enter the internal space sealed by these four screw portions from the outside.

Several through holes 25 are formed in the external electrode 2. This is a hole for passing the cleaning liquid. The front end of the external electrode 2 has an opening through which a cleaning liquid can enter and exit. A portion surrounded by the external electrode 2 and having no internal electrode 3 is a cavity 26. This is to protect the tip of the temperature sensor 4. A female screw hole 29 is formed in the cavity 28 of the internal electrode 3, and the female screw hole 29 is formed.
Then, the temperature sensor 4 is fixed to the internal electrode by screwing the male screw portion 30 of the temperature sensor. Of course, both are electrically insulated. Since this screw portion is also subjected to the fading process, airtightness is maintained. An O-ring 23 seals between the flange 32 of the insulating insulator 5 and the end face of the internal electrode 3. The rear surface of the flange 32 and the forehead of the base cylinder 6 are sealed by an O-ring 24. Therefore, the internal space 31 of the internal electrode 3 and the base tube 6
Inner space 34 and through hole 3 of insulating insulator 5
3 is shut off from the cleaning solution. The tail of the temperature sensor 4 is located in the internal space 31 of the internal electrode 3, where air exists and the cleaning liquid does not enter. Therefore, there is no contamination by the cleaning liquid, and no fluctuation of the capacity due to the entry of the cleaning liquid occurs.

The temperature sensor leads 18, 19 pass through cavities such as the internal space 31, the through hole 33, and the internal space 34, and are connected to an appropriate external electric circuit through the tube 16 from behind the temperature sensor 4. The internal electrode 3 comes into contact with a connection spring 11 for an internal electrode, and the tip of an internal electrode lead wire 21 is soldered to this spring 11. The internal electrode lead 21 passes through the through hole 33 and the internal space 34, and is connected to an external circuit through a shielded cable. Although the internal electrode 3 and the spring 11 are not pressed by soldering or the like, they are strongly pressed by an elastic force, so that the contact is good. The internal electrode 3 is insulated from the external electrode 2 by an insulating insulator.

The external electrode 2 is in contact with the base cylinder 6 made of metal by screw portions 35 and 36. External electrode connection spring 1 provided between base cylinder 6 and insulating insulator 5
2 is a lead line of the external electrode. The tip of the external electrode lead wire 20 is soldered to the spring 12.

The external electrode 2 and the internal electrode 3 are arranged concentrically, and a cleaning liquid enters into a narrow space 27 between the through hole 25 and the opening. Since the cleaning liquid is a mixture of a petroleum-based solvent and a detergent, the DC resistance is large and a DC current hardly flows.
However, since the dielectric constant is considerable and the space 27 is narrow, there is considerable capacitance. That is, the internal electrode 3 and the external electrode 2 constitute a capacitor. The impedance can be obtained by multiplying this by an AC voltage to obtain a current. The detergent concentration in the cleaning liquid can be determined from the impedance change. Concentrically arranged and the gap 27 is narrow, so the above-mentioned Japanese Patent Publication No. 7-28993
The capacity is larger than that of Japanese Patent Publication No. 7-57277. That is, the sensitivity is high.

However, the present invention is more excellent in that correction by temperature is made possible. The peripheral circuit of the temperature sensor will be described with reference to FIG. The temperature sensor 4 may be any element whose resistance or electromotive force changes depending on the temperature, but a thermistor is used here.

The temperature sensor 4 is connected by the lead wires 18 and 19.
The terminals at both ends are led out. This is the resistance / temperature converter 40 including the reference power supply 41, the noise filter 4
2. The signal reaches the A / D converter 45 via the noise filter 43 and the amplifier circuit. The thermistor is a semiconductor temperature measuring element whose resistance r decreases as the temperature increases. Elements having opposite characteristics may be used. Although the reference voltage is divided by the resistors R ₂ and R ₃ , the resistance r of the thermistor and the input resistance R ₁ are connected in parallel to the resistor R ₃ , so that the potential at the point a varies with the resistance r of the thermistor 4. . Therefore, this is a resistor / voltage circuit that obtains the value of the resistor r as the potential at the point a. Since the reference voltage is a DC reference voltage, the divided voltage is also a DC.

However, since alternating current may be applied between the internal electrode 3 and the external electrode 2 and noise enters, two-stage noise filters 42 and 43 are provided. Noise filter 42
It has become a low-pass filter installed at the other end of the resistor R ₄ and the capacitor C ₂ connecting the capacitor C _2. Since noise with a period shorter than the time constant C ₂ R ₄ drops, alternating current applied between the inner and outer electrodes also drops. A two-stage filter is provided to more completely cut noise.
This can be done in one step.

The amplification stage includes an amplifier 44. The signal from which the noise has been removed is input to the inverting input of the amplifier 44.
C ₄ is are still put in for the filter. Further, this passes through an integrating circuit consisting of a resistor R _{11 and a} capacitor C ₅ ,
/ D conversion. When the temperature rises, the resistance r of the sensor 4 decreases, so that the potential at the point a decreases, and this is amplified by the amplifier 44. Up to this point, it is an analog value, but A /
D-converted to a digital value. This is a data value representing the temperature T of the cleaning liquid.

Referring to FIG. 5, the concentration detection amplifier circuit will be described. This circuit measures an induced current flowing between the inner and outer electrodes by applying an AC voltage. There is no special oscillating circuit for generating alternating current, and a square wave is generated by switching the switches S ₁ and S ₂ by software. In addition, the voltage range was automatically switched so that measurement of different detergents could be performed immediately.

The reference power supply 46 generates a constant DC voltage. This enters the inverting input of an amplifier 47 via a resistor R _15. The output of the amplifier 47 is fed back to the inverting input by a capacitor C ₅ and the resistor R _13. Reference power source 46 is connected to the contact side of the S ₁ switch 50 via a resistor R _15.
S ₁ switch 50 is connected to the non-inverting input of the amplifier 47. Therefore, the amplifier 47 only amplifies the current.

[0028] S ₂ switch 5 in addition to the S ₁ switch 50
1, 52 are used here, but both are switched synchronously by software. The S ₁ and S ₂ switches have a b terminal and a c terminal, but all these switches simultaneously contact the terminal of the same symbol. FIG. 5 shows a state in contact with the terminal b. Since the amplifier 47 has the potential of the reference power supply Vs, the output also becomes Vs. When the terminal is switched to the terminal c, the output of the amplifier 47 becomes 0V. By switching the switch S ₁ by software, a rectangular wave having a height of Vs is generated as an output of the amplifier (amplifier) 47.
The frequency of the square wave can be freely determined by a computer.

[0029] This is applied to the external electrodes 2 of the density sensor through a resistor R _14. The internal electrode 3 is connected to the resistor RD. The current i flowing between the inner and outer electrodes is iR at both ends of the resistor RD.
D voltage is generated. That is, a voltage equal to the product of the inter-electrode current i and the resistance RD is proportional. The current between the sensor electrodes can be determined by amplifying the voltage of the resistor RD. This is inversely proportional to the impedance between the electrodes, and the concentration is substantially proportional to the impedance in a certain range.

Since an oscillation circuit is not provided and software is used, an AC of any frequency can be generated at 100 kHz or 1 MHz. The current must be rectified to apply an alternating current to the inner and outer electrodes, which are capacitors, and to obtain the current. But using a switch S ₂ has a place of diode instead of the diode in this circuit. When switches S ₁ and S ₂ are in contact with terminal b, amplifier 4
7 generates Vs, and a current flows in the resistor RD in the forward direction. Therefore, the S ₂ switch 51 has a high potential and the S ₂ switch 52 has a low potential. The voltage between the two is the aforementioned value RDi
It is. The high side enters the non-inverting input of the positive side amplifier 48. The low potential side enters the non-inverting input of the negative side amplifier 49.

On the contrary, S₁Switch 50, S_TwoSwitch 5
When the terminals 1 and 52 are in contact with the terminal c,
It is a half cycle. At this time, S_TwoSwitches 51 and 52
Switch to terminal c. Current flows in the opposite direction to the resistance RD
Flows, so S_TwoThe switch 51 has a higher potential,
The beam amplifier 48 has a higher potential. Because it is
The amplifier 48 has a high potential and the amplifier 49 has a low potential. I mean
S₁Switch 50, S _TwoSwitches 51 and 52
This means that the alternating current of the shape wave is full-wave rectified. Originally square wave
Therefore, a full-wave rectified version of this has a little ripple.
DC.

Since the signal is connected to the non-inverting input, the signal applied to the resistor RD can be amplified by the two amplifiers 48 and 49. Thereby, the input impedance is increased. The voltage itself can also be amplified, and the degree of amplification can be increased from 10 times to 200
It can be changed up to 0 times. Low-potential side amplifier 4
9 outputs k and the output j of the high potential side of the amplifier 48 is connected by a resistor string R ₂₇ to R ₁₈ in. S ₄ switch 61 is for switching the amplification degree. The fixed end is connected to the inverting input of the amplifier 48 on the high potential side. S ₄ switch 6
1 can be switched to the connection point of each resistor. The non-inverting input is multiplied by the voltage of the aforementioned RDi, which is equal to the voltage between the non-inverting inputs. The inverting input of the amplifier 49 is connected to the connection point h of the resistors R ₂₆ and R ₂₇ . RDi is applied to the resistance from the point x are in contact S ₄ switch 61 to point h of the resistor string in this example. Therefore, the voltage between the output terminals jk is (Di)
It is obtained by multiplying the ratio of (resistance between k) / (resistance between hx). By S ₄ switch 61 can change the denominator of this multiplier. Thus, the magnification is changed from 10 times to 2000 times. The range of the magnification and the increment are the resistance rows R _{27 to} R
You can change it freely by changing ₁₈ . S
Switching of the _four switches can of course be performed by software.

The output k of the amplifier 49 and the output j of the amplifier 48 enter the non-inverting input and the inverting input of the amplifier 55, and are differentially amplified by the amplifier 55. Since the high potential side is connected to the inverting input and the low potential side is connected to the non-inverting input, the output becomes a negative voltage. This should be proportional to the impedance between the inner and outer electrodes, but in practice there may be a zero offset. In order to correct the zero point, the S ₃ switch 53,54 e
Switch to the terminal side. At this time, it is sufficient that the output of the differential amplifier 55 is 0, but this is not necessarily the case because the amplifier has an offset Vof.

Therefore, an amplifier 56 for zero adjustment, a capacitor C ₈ , and an S ₅ switch 62 are provided. S ₅ switch 62 normally is made the d terminal side. S ₅ switch 62 when switching the S ₃ switches 53, 54 to the terminal e is switched to terminal e at the same time. The offset Vof of the amplifier 55 becomes the inverting input of the amplifier 56. Since the non-inverting input is 0V, a negative voltage obtained by amplifying the difference appears at the output of the amplifier 56. The voltage pulls the potential at the connection point m of the resistor R ₃₄ and R _35. Then, the non-inverting input of the preceding amplifier 55 is dragged down. Eventually, both inputs of the amplifier 56 become 0V. That is, the output of the amplifier 55 is 0
V. The zero point has now been adjusted. That is, S
The _third switch 53, 54 and S ₅ switch 62 is automatically adjusted zero point by switching to e terminal.

At this time, the voltage of the inverting input of the amplifier 56 (0
The voltage difference Vd in V) and the output appears at the capacitor C _8.
Capacitor C ₈ when switching S ₅ switch 62 to the terminal d retains its potential Vd. The potential at the point m is also stored as it is. That is, the state without the offset is saved.

The signal obtained here is a DC signal, but contains noise. Therefore, the AC component is removed by the resistors R ₃₉ and R ₄₀ and the capacitor C ₁₈ , and the AC component is amplified by the amplifier 57. Until now, the voltage was negative, but the amplifier 58
Changes the negative voltage to a positive voltage, and the diodes D ₁ , D
₂ prevents negative voltage from occurring. At point n, a positive voltage is generated. The reference power supply 63, resistors R _47, R _48, diode D _3, such as an amplifier 59 is a limiter. Reference voltage p is one the reference power by dividing by R ₄₇ and R _48. When p is greater than the voltage is out D ₃ pulls the potential of the n points on the reference voltage p. This is for protecting the A / D converter. For p smaller voltage passes as it potential is reverse biased D _3. This is converted into a digital signal Z by the A / D converter 60. This is a value indicating the impedance between the inner and outer electrodes.

The detergent concentration is a function of the impedance between the inner and outer electrodes and the temperature, once the type of detergent (soap) and the solvent are determined. The solvent is fixed, and the type of soap is known in advance. Temperature and impedance are unknown variables, which are determined by the sensor of the present invention. Dependency of detergent type, impedance and temperature is measured in advance to determine the relationship.

FIG. 6 is a graph showing the relationship between the temperature and the voltage W between the inner and outer electrodes when the concentration of 1% is applied to the three types of soaps by the circuit shown in FIG. The horizontal axis is temperature, and the vertical axis is W. In soap number 0, the impedance value W increases almost linearly with temperature. The value at 25 ° C. and the reference value are 800 at this time. 850 at 45 ° C
To increase. At 0 ° C., it is 710. For the soap number 0 of 1% concentration, the impedance value W at an arbitrary temperature in the range of 1 ° C. to 45 ° C. can be obtained from this result. If it is 2%, this value should be doubled. Concentration and impedance should be proportional. Then, from this graph, 1% at temperature T
The W value of the cleaning liquid containing the detergent of the soap number 1 having the concentration is determined. This is called w ₀ (T). Temperature can be measured by a temperature sensor. Since the output W value of the A / D converter 60 is known, the density at this time is given by W / w ₀ (T).

The detergent of soap number 1 has a smaller value of W. It is 610 when the reference temperature is 25 ° C. and the concentration is 1%. 4
It is 650 at 5 ° C and 380 at 0 ° C. This is not linear with temperature, but it can be. The value w ₁ (T) of the 1% concentration at each temperature may be stored and stored. Also in this case, knowing the value W at the temperature T, the concentration can be obtained from W / w ₁ (T).

The detergent of soap number 2 has a lower W value. 520 when the reference temperature is 25 ° C. 5 at 45 ° C
60 and 320 at 0 ° C.

As described above, the W value at 1% is obtained as a function of the temperature for each type of soap and stored, and the W and the temperature T are measured by this sensor, and the concentration can be calculated at that temperature. It is a novel point of the present invention that the temperature can be corrected. The necessity will be described. The cleaning liquid for dry cleaning is not always used at 25 ° C. The temperature of the cleaning liquid also varies depending on the ambient environmental temperature. In the case of soap number 1, since it is 650 at 45 ° C. and 380 at 0 ° C., it changes 1.7 times during this period. 25 even if there is no significant temperature change
There are 50 changes in the value in the range of 10 ° C.
% Fluctuation range. The measurement error due to such a temperature must not be neglected because the detergent concentration must be strictly defined.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, a cleaning liquid is passed between electrodes combined with inner and outer cylinders, an AC voltage is applied, impedance is substantially measured, and a detergent concentration is obtained from both impedance and temperature data. Such a sensor is provided at any part of the cleaning liquid circulation system. This detergent concentration sensor may be provided in both the inlet and outlet channels of the drum in which the laundry is placed. Then measure the concentration at the exit,
The missing detergent can be added and the concentration at the inlet checked to see if the added amount was appropriate.
Since there is a filter in the circulation system, the loss of detergent due to this can be determined.

Further, this sensor can be installed in a washing liquid tank, but in that case, it is provided at a position floating from the bottom of the tank. The sensor knows the detergent concentration and compares it with the desired value so that the missing detergent is automatically added to the washing liquid tank or other circulation system. FIG. 7 shows a flow including this. Since the sensor of the present invention can determine the soap temperature and the concentration, the soap temperature and the concentration are displayed, and the number of the soap currently used is also displayed. Since the gain (amplification degree) of the amplifier changes automatically depending on the soap, the current gain is also displayed. The output of the A / D converter 60 indicating the impedance between the inner and outer electrodes is also displayed. Then, the temperature of the soap solution and the detergent concentration are obtained by the sensor of the present invention, and the insufficient detergent is added. To do this, he opens the soap pump and adds detergent.

[0044]

According to the present invention, in the case of dry cleaning for removing dirt by mixing a detergent in a petroleum solvent and circulating the detergent in a drum containing clothes, the sensor of the present invention is provided in the circulating system of the washing liquid, thereby causing temperature fluctuation. It is also possible to accurately determine the detergent concentration. Since the change in impedance due to temperature is not negligible, the present invention enables strict control of the detergent concentration for the first time. Although the lead wire for the temperature sensor and the lead wire for the internal electrode pass through the cavity inside the internal electrode, the lead wire is not wetted by the cleaning liquid because it is sealed. Furthermore, since the zero point can be automatically adjusted, an accurate value can always be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of an assembled state of a detergent concentration sensor for dry cleaning according to an embodiment of the present invention.

FIG. 2 is a sectional view of the same dry cleaning detergent concentration sensor.

FIG. 3 is an exploded view of the same dry cleaning detergent concentration sensor.

FIG. 4 is an amplifier circuit of a temperature sensor.

FIG. 5 is an amplification detection circuit of a concentration detection sensor.

FIG. 6 is a graph showing a measurement result of an impedance value according to a temperature of a cleaning liquid containing a 1% concentration soap.

FIG. 7 is a flowchart illustrating an example of a dry cleaning detergent concentration control method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concentration sensor 2 External electrode 3 Internal electrode 4 Temperature sensor 5 Insulation insulator 6 Base cylinder 7 Female screw part 8 Male screw part 9 Female screw part 10 Male screw part 11 Connection spring for internal electrodes 12 Connection spring for external electrodes 13 Female screw hole 14 Straight Joint 15 Male Thread 16 Tube 17 Nut 18 Temperature Sensor Lead Wire 19 Temperature Sensor Lead Wire 20 External Electrode Lead Wire 21 Internal Electrode Lead Wire 22 Shield Wire 23 O Ring 24 O Ring 25 Through Hole 26 Cavity 27 Void 28 Internal Cavity 29 Female threaded hole 30 Male threaded part 31 Internal space 32 Flange part 33 Through hole 34 Internal space 35 Male threaded part 36 Female threaded part 37 Shield cable 38 Screw head 40 Resistance / voltage conversion part 41 Reference power supply 42 Noise filter 43 Noise filter 44 Amplifier 45 A / D converter

Claims (3)

[Claims] An AC voltage is applied between two electrodes immersed in a cleaning liquid to determine the impedance of the cleaning liquid, the temperature of the cleaning liquid is determined by a temperature sensor, and the detergent concentration is determined from both data. A dry cleaning detergent concentration sensor, wherein 2. An external electrode 2 having a cylindrical through hole 25, a cylindrical internal electrode 3 provided concentrically with a gap in the external electrode 2, and a temperature sensor 4 protruding from the internal electrode 3. , A lead wire 21 of the internal electrode, a lead wire 20 of the external electrode, and lead wires 18 and 19 of the temperature sensor, and a cavity of the internal electrode through which the lead wire passes is shielded from the cleaning liquid. A dry cleaning detergent concentration sensor characterized in that a cleaning solution temperature is determined, an alternating current is applied between inner and outer electrodes to determine an impedance, and a detergent concentration is determined from both data. 3. An apparatus comprising two electrodes and a temperature sensor, wherein an impedance is obtained by applying an AC voltage between the two electrodes immersed in the cleaning liquid, a temperature of the cleaning liquid is obtained by the temperature sensor, and a detergent concentration is obtained from both data. A detergent concentration sensor is provided in either the washing drum or the washing liquid circulation system including the washing drum and the washing solution tank, and the desired detergent concentration is compared with the detergent concentration of the current washing solution. A dry cleaning detergent concentration control method characterized by being added to a circulation system.