Washing machine and washing instructions

Abstract

To provide a washing machine which can optimize a washing condition with respect to arbitrary laundry.SOLUTION: A washing machine 1 includes: a washing liquid tub 10 for storing washing liquid containing a detergent; a sampling device 20 for sampling the washing liquid; a concentration estimation device 30 for estimating effective detergent concentration of the washing liquid by estimating interfacial tension of the washing liquid which has been sampled by the sampling device 20; and a control device 60 for performing control according to the effective detergent concentration estimated by the concentration estimation device 30.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a washing machine and a washing method.

Background Art

[0002] Washing machines that use a cleaning liquid containing detergent to wash laundry are in use. There are cases where it is preferable to change the amount of detergent used according to the degree of soiling of the laundry. As an example, Patent Document 1 discloses a washing machine provided with a detergent supply device for putting detergent into a washing tub, which can change the effective detergent concentration according to the material of the laundry and the degree of soiling.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Especially in commercial washing machines, as washing conditions, for example, there are the amount of detergent input, washing time, amount and temperature of the cleaning liquid, mechanical force, amount and frequency of quick drain, etc. It is desirable to accurately estimate in advance the material of the laundry, the degree of soiling (amount of contamination), the ease of dirt removal (washing speed), the amount of lint and oil (scum, sebum, soap residue), etc., and set the above-mentioned washing conditions. Also, it is necessary to keep the foaming of the cleaning liquid within an appropriate range.

[0005] If you can predict the degree of soiling and ease of stain removal of laundry with relative accuracy, you can adjust the washing conditions, such as the amount of detergent to use, according to the laundry. However, it is often difficult to know the material of the laundry, the degree of soiling, and how easily the stains can be removed in advance, making it challenging to set appropriate washing conditions. In such cases, in order to prevent incomplete cleaning, the washing conditions are set assuming the worst possible washing load, resulting in the consumption of more water (washing solution), detergent, power energy, heating energy, and washing time than necessary.

[0006] Therefore, the present invention aims to provide a washing machine and a washing method that can optimize washing conditions for any type of laundry. [Means for solving the problem]

[0007] A washing machine according to one aspect of the present invention comprises a washing liquid tank for storing a washing liquid containing detergent, a sampling device for sampling the washing liquid, a concentration estimation device for estimating the effective detergent concentration of the washing liquid by estimating the interfacial tension of the washing liquid sampled by the sampling device, and a control device for performing control according to the effective detergent concentration estimated by the concentration estimation device.

[0008] In the washing machine described above, the concentration estimation device may have a dilution unit that dilutes the cleaning solution sampled by the sampling device, and the concentration estimation device may estimate the effective detergent concentration of the cleaning solution by estimating the interfacial tension of the diluted solution obtained by the dilution unit.

[0009] In the washing machine described above, the concentration estimation device may include a critical micelle concentration determination unit that determines whether the surfactant concentration of the diluent is less than the critical micelle concentration based on a physical quantity or physical phenomenon that depends on the interfacial tension of the diluent, and an effective detergent concentration estimation unit that estimates the effective detergent concentration of the washing solution based on the dilution ratio of the diluent by the dilution unit and the determination result of the critical micelle concentration determination unit.

[0010] In the washing machine described above, the dilution unit can continuously change the dilution ratio, and the effective detergent concentration estimation unit may estimate the effective detergent concentration of the cleaning solution based on the dilution ratio of the diluted solution when it is determined that the surfactant concentration of the diluted solution has fallen below the critical micelle concentration.

[0011] In the washing machine described above, the dilution unit can change the dilution ratio in steps, and the effective detergent concentration estimation unit may estimate that the effective detergent concentration of the cleaning solution is lower than the concentration category corresponding to the dilution ratio in the dilution unit of the dilution solution when it is determined that the surfactant concentration of the diluted solution is less than the critical micelle concentration.

[0012] The washing machine described above further includes a chemical injection device for injecting the detergent into the washing solution, and the control device may cause the chemical injection device to inject the detergent so as to maintain the effective detergent concentration at or above a predetermined control concentration.

[0013] In the washing machine described above, the control device may terminate the washing process when it is estimated that the effective detergent concentration has stopped decreasing over time.

[0014] The washing machine described above may be configured such that multiple washing fluid tanks are arranged so that the laundry and the washing fluid move through each tank in sequence.

[0015] In the washing machine described above, the sampling device may sample the cleaning solution discharged from the cleaning solution tank or the cleaning solution that has been processed after being discharged from the cleaning solution tank.

[0016] In the washing machine described above, the control device may replace at least a portion of the cleaning solution in the cleaning solution tank with new cleaning solution if the rate of decrease in the effective detergent concentration of the cleaning solution is greater than a predetermined standard.

[0017] A washing method according to an aspect of the present invention includes a step of sampling a cleaning liquid, a step of estimating the effective detergent concentration of the cleaning liquid by estimating the surface tension of the sampled cleaning liquid, and a step of managing the cleaning liquid or checking the progress of washing based on the estimation result of the effective detergent concentration.

Effect of the Invention

[0018] According to the present invention, the washing conditions can be optimized for any laundry.

Brief Description of the Drawings

[0019] [Figure 1] It is a schematic diagram showing the configuration of a washing machine according to the first embodiment of the present invention. [Figure 2] It is a schematic diagram showing the configuration of the concentration estimation device of the washing machine in FIG. 1. [Figure 3] It is a schematic diagram showing the configuration of a washing machine according to the second embodiment of the present invention.

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a washing machine 1 according to the first embodiment. The washing machine 1 is a device that can implement an embodiment of the washing method according to the present invention.

[0021] The washing machine 1 includes a washing tub (cleaning liquid tub) 10 that stores a cleaning liquid (washing water) containing a detergent, a sampling device 20 that samples the cleaning liquid from the washing tub 10, a concentration estimation device 30 that estimates the effective detergent concentration of the cleaning liquid sampled by the sampling device 20, that is, calculates the concentration of the surfactant that is free from the surface tension and converts this into the concentration of the active detergent, a solvent supply mechanism 40 that supplies a solvent (water) to the washing tub 10, a chemical injection device 50 that injects a detergent into the cleaning liquid in the washing tub 10, and a control device 60 that controls the washing tub 10, the solvent supply mechanism 40, and the chemical injection device 50 according to the effective detergent concentration estimated by the concentration estimation device 30, that is, the washing余力.

[0022] The washing tub 10 has an overflow portion 11 that causes the cleaning liquid to overflow so as to maintain a constant water level, a stirrer 12 that stirs the cleaning liquid, and a drain valve 13 that discharges the cleaning liquid from the bottom. The washing tub 10 adsorbs the dirt on the laundry to the surfactant of the detergent by stirring the cleaning liquid with the stirrer 12 in a state where the laundry (object to be cleaned) is immersed in the cleaning liquid.

[0023] The sampling device 20 can be composed of a pump that sucks the cleaning liquid from the washing tub 10, a valve mechanism that causes the cleaning liquid to flow out by its head, and the like. The sampling device 20 can be configured to sample the cleaning liquid periodically or in response to an instruction from the control device 60.

[0024] The concentration estimation device 30 may be one that directly measures the surface tension of the sampled cleaning liquid and converts it into the effective detergent concentration, etc., but it is preferably configured to have a dilution unit 31 that dilutes the cleaning liquid sampled by the sampling device 20. By diluting the cleaning liquid, the liquid temperature is likely to be stabilized, and the ratio of impurities such as lint and oil (scum, sebum, soap residue) is also reduced, so the measurement error is reduced. As methods for measuring the surface tension, for example, the pendant drop method, the ring method, the plate method, the maximum bubble pressure method, etc. are known.

[0025] The dilution unit 31 generates a diluted liquid by adding water (solvent) in a certain ratio to the cleaning liquid sampled by the sampling device 20. As an example, as shown in detail in FIG. 2, the dilution unit 31 has a cleaning liquid metering valve 311 that quantitatively supplies the sampled cleaning liquid and a water metering valve 312 that quantitatively supplies water (solvent), and may be configured to continuously generate a diluted liquid. When the sampling device 20 has quantification, the cleaning liquid metering valve 311 can be omitted. Also, a metering pump or the like may be used instead of the cleaning liquid metering valve 311. As a further alternative, the dilution unit 31 may have a batch type configuration including a cleaning liquid metering container that measures the cleaning liquid, a water metering container that measures water, and a mixing container that mixes the cleaning liquid measured by the cleaning liquid metering container and the water measured by the water metering container.

[0026] The concentration estimation device 30 may more preferably have the following configuration: a dilution unit 31 that dilutes the cleaning solution sampled by the sampling device 20; a critical micelle concentration determination unit 32 that determines whether the concentration of free surfactant in the diluted solution is less than the critical micelle concentration (CMC) based on a physical quantity or physical phenomenon that depends on the interfacial tension of the diluted solution obtained by the dilution unit 31; and an effective detergent concentration estimation unit 33 that estimates the effective detergent concentration of the cleaning solution based on the dilution ratio of the diluted solution by the dilution unit 31 and the determination result of the critical micelle concentration determination unit 32.

[0027] The critical micelle concentration discrimination unit 32 may be configured to check the dynamic surface tension using the flow velocity of the diluent, but it is preferable that it be configured to check the static surface tension of the diluent. The static surface tension is a small, approximately constant value when the free surfactant concentration is equal to or greater than the critical micelle concentration, and increases rapidly as the concentration decreases when the free surfactant concentration falls below the critical micelle concentration. For this reason, the critical micelle concentration discrimination unit 32 can be configured to determine, based on a physical quantity or physical phenomenon, whether the static surface tension of the diluent is clearly greater than the static surface tension at the critical micelle concentration.

[0028] For example, the critical micelle concentration determination unit 32 may be configured to determine whether the concentration of free surfactant in the diluent is less than the critical micelle concentration by continuously introducing the diluent into the observation container 321 from the bottom, overflowing the diluent from the upper opening of the observation container 321, and checking the height of the rise in the liquid surface due to surface tension using a liquid level detector 322, which may consist of, for example, a camera, a photocell, or an ultrasonic sensor.

[0029] More specifically, static surface tension can be estimated by measuring the height of the liquid surface rise as a physical quantity. Alternatively, by pre-determining the liquid surface rise height corresponding to the CMC, it can be determined that the concentration of free surfactant in the diluent has fallen below the critical micelle concentration by detecting the physical phenomenon of the liquid surface rising above that height, without needing to estimate the static surface tension.

[0030] The height of the liquid surface rise due to surface tension can also be confirmed by measuring the weight of the container. Furthermore, the critical micelle concentration discrimination unit 32 may be configured to determine whether the value of the surface tension of the diluent is less than or equal to the value corresponding to the critical micelle concentration by a method that conforms to well-known methods for quantifying surface tension, such as the suspension drop method, ring method, plate method, or maximum bubble pressure method. Other examples of physical quantities based on surface tension include the contact angle between an object and a liquid, and the average diameter and number of bubbles generated under certain conditions. Examples of physical phenomena based on surface tension include whether an object with an appropriate specific gravity and shape floats or sinks when placed on an interface, and whether a liquid placed on a mesh of an appropriate material and mesh size stays on the mesh or passes through and falls off.

[0031] Conventional methods for quantifying interfacial tension are prone to large measurement errors due to factors such as foaming of the cleaning solution, lint, oil, and liquid temperature, as well as problems such as blockage of the quantification mechanism by foreign matter. This makes measurement inside the washing machine 1, which generates vibrations, difficult and time-consuming. However, by configuring the critical micelle concentration discrimination unit 32 to simply determine whether the free surfactant concentration of the diluent is below the critical micelle concentration, that is, to make a threshold-based determination, the determination results can be obtained quickly and accurately.

[0032] The effective detergent concentration estimation unit 33 stores the effective detergent concentration corresponding to the critical micelle concentration, and when the determination result of the critical micelle concentration determination unit 32 is less than the critical micelle concentration, it estimates the effective detergent concentration of the cleaning solution as being less than the concentration obtained by multiplying the effective detergent concentration corresponding to the critical micelle concentration by the dilution ratio in the dilution unit 31. The effective detergent concentration estimation unit 33 may be configured as a physical electrical circuit, or it may be configured by having a computer device having memory, a processor, etc., execute an appropriate program.

[0033] When concentration estimation by the concentration estimation device 30 is performed repeatedly at short intervals, the effective detergent concentration estimation unit 33 may estimate that the effective detergent concentration of the cleaning solution at that time is approximately equal to the concentration obtained by multiplying the effective detergent concentration corresponding to the critical micelle concentration by the dilution ratio in the dilution unit 31, if the determination result of the critical micelle concentration determination unit 32 is less than the critical micelle concentration. Conversely, the concentration estimation device 30 is configured such that the critical micelle concentration determination unit 32 makes a determination based on a threshold whether or not the free surfactant concentration in the dilution solution is less than the critical micelle concentration, and the effective detergent concentration estimation unit 33 estimates the effective detergent concentration considering the dilution ratio of the dilution solution in the dilution unit 31. As a result, the effective detergent concentration can be appropriately estimated in a relatively short time, and continuous monitoring of the cleaning solution can be easily realized.

[0034] Furthermore, if the dilution ratio in the dilution unit 31 can be continuously changed in the concentration estimation device 30, it is also possible to quantify the effective detergent concentration of the cleaning solution. For example, if the dilution ratio in the dilution unit 31 is continuously increased, and the critical micelle concentration determination unit 32 determines that the concentration of free surfactant in the diluted solution has fallen below the critical micelle concentration, the effective detergent concentration estimation unit 33 can estimate the effective detergent concentration of the cleaning solution based on the dilution ratio of the diluted solution at that point.

[0035] Furthermore, if the dilution ratio in the dilution unit 31 can be changed in stages, the effective detergent concentration of the cleaning solution can also be estimated as a series of concentration categories. In this case, the effective detergent concentration estimation unit 33 may be configured to estimate that the effective detergent concentration of the cleaning solution has fallen below the concentration category corresponding to the dilution ratio in the dilution unit 31 of the dilution solution when it is determined that the concentration of free surfactant in the dilution solution is less than the critical micelle concentration. In this way, by understanding the effective detergent concentration as multiple concentration categories, the cycle time for estimating the effective detergent concentration can be shortened, and the concentration of the cleaning solution can be managed more flexibly by understanding the change in the effective detergent concentration in the cleaning solution.

[0036] The solvent supply mechanism 40 supplies water, which will be the solvent component of the cleaning solution, and water for rinsing, such as tap water, to the washing tub 10. The solvent supply mechanism 40 may be configured to have a water supply valve 41 that opens and closes the flow path. The solvent component of the cleaning solution may be a solvent.

[0037] The chemical injection device 50 supplies detergent to the washing tub 10. The chemical injection device 50 only needs to be quantitative and can be appropriately selected according to the properties of the detergent.

[0038] The control device 60 controls the operation of the washing machine 1. The control device 60 may be configured as a physical electrical circuit having relays, etc., or it may be configured by causing a computer device having memory, a processor, etc., to execute an appropriate program. In addition, the control device 60 may be configured integrally with the effective detergent concentration estimation unit 33 of the concentration estimation device 30.

[0039] Specifically, the control device 60 controls other components to perform, for example, the washing solution supply, stirring, and rinsing processes in sequence. The control device 60 may be configured to supply a certain amount of detergent to the chemical injection device 50 when the concentration estimation device 30 determines that the concentration of free surfactant in the diluent is below the critical micelle concentration. The control device 60 may also be configured to terminate the stirring process if a certain amount of time has elapsed since the detergent was supplied without the surfactant concentration falling below the critical micelle concentration.

[0040] As washing progresses, the dirt on the laundry combines with the surfactant, which is the main active ingredient in the detergent, and the surfactant concentration in the washing solution (the concentration of surfactant that is free and not combined with dirt) decreases. Therefore, by setting the dilution ratio in the dilution unit 31 to the ratio of the critical micelle concentration of the surfactant, which is the lower limit of the effective detergent concentration at which the washing solution can maintain its washing ability, it can be determined that the effective detergent concentration of the washing solution is above the required concentration if the free surfactant concentration in the diluted solution does not fall below the critical micelle concentration, and that the effective detergent concentration of the washing solution is insufficient if the free surfactant concentration in the diluted solution falls below the critical micelle concentration.

[0041] In this way, the washing machine 1 performs washing while checking whether the effective detergent concentration has reached the lower limit using the concentration estimation device 30. This allows for optimization of the effective detergent concentration, the length of the agitation process, etc., even when the degree of soiling (washing load) of the laundry is unknown, thereby achieving a high cleaning effect while suppressing the consumption of detergent, water, and energy. Furthermore, the concentration estimation device 30, which qualitatively determines whether the surfactant concentration of the dilution water is below the critical micelle concentration, can make a determination relatively quickly, so the effective detergent concentration of the washing solution can be monitored virtually continuously and the washing process can be controlled.

[0042] For example, the control device 60 may be configured to inject a certain amount of detergent into the chemical injection device 50 when the concentration estimation device 30 estimates that the effective detergent concentration has fallen below a predetermined lower limit. This ensures that the effective detergent concentration of the washing solution is maintained within a certain range above a predetermined control concentration, regardless of the degree of soiling of the laundry, thereby suppressing the wasteful consumption of water, detergent, energy, etc., while guaranteeing a high cleaning effect. Alternatively, instead of injecting additional detergent, the system may be configured to increase the mechanical force or washing temperature during washing. These methods may also be used in combination.

[0043] Furthermore, the control device 60 may be configured to determine that the effective detergent concentration has stopped decreasing over time and terminate the washing process when it is estimated that the effective detergent concentration has stopped decreasing over time. In this way, by confirming that the effective detergent concentration has stopped decreasing and terminating the washing process, excessive consumption of water, detergent, energy, time, etc., can be prevented. Regarding the stopping of the decrease in effective detergent concentration, for example, if it is estimated that the effective detergent concentration has fallen below a predetermined lower limit and a certain amount of detergent is injected by the chemical injection device 50, and then a preset time limit has elapsed without the effective detergent concentration falling below the predetermined lower limit again, it can be estimated that the effective detergent concentration has stopped decreasing.

[0044] The control device 60 may perform a quick drain by opening the drain valve 13 and replacing at least a portion of the cleaning solution in the washing tub 10 with new cleaning solution (water supplied from the solvent supply mechanism 40 and detergent supplied from the chemical injection device 50) if the rate of decrease in the effective detergent concentration of the cleaning solution is greater than a predetermined standard (for example, if the time from when a certain amount of detergent is injected by the chemical injection device 50 until the effective detergent concentration falls below a predetermined lower limit is shorter than a preset lower limit time). When the laundry is heavily soiled, the quick drain can be performed efficiently.

[0045] One embodiment of the washing method according to the present invention, performed in the washing machine 1 described above, comprises the steps of: sampling the washing liquid from a washing liquid tank that stores the washing liquid; estimating the effective detergent concentration of the washing liquid by estimating the surface tension of the sampled washing liquid; and managing the washing liquid or checking the progress of washing based on the estimated effective detergent concentration. In this way, by estimating the effective detergent concentration by estimating the surface tension of the washing liquid, the amount of detergent to be added, the washing time, etc. can be optimized according to the state of the washing liquid at that time, thereby saving water, detergent, energy, time, etc., while ensuring sufficient washing effect.

[0046] Next, a second embodiment of the present invention will be described. Figure 3 is a schematic diagram showing the configuration of a washing machine 1A according to the second embodiment of the present invention. For the washing machine 1A in Figure 3, components similar to those in the washing machine 1 in Figure 1 are denoted by the same reference numerals, and redundant explanations may be omitted.

[0047] Washing machine 1A is a continuous washing machine that can continuously load laundry and washes the laundry as it moves through the machine. Washing machine 1A has multiple washing solution tanks capable of storing washing solution containing detergent (multiple first washing tanks 101 to 9th washing tanks 109 that share the washing process of the laundry, a finishing tank 110 that finishes the laundry discharged from the final stage 9th washing tank 109, a hot water tank 121 that recovers the washing solution discharged from the 8th washing tank 108, and a cold water tank 122 that recovers the washing solution (rinse water) discharged from the finishing tank 110, a hot water line 71 that introduces washing solution from the hot water tank 121 to the first washing tank 101, a rinse water line 72 that supplies rinse water from the cold water tank 122 to the 9th washing tank 109, and a cold water tank 12 The system includes a cold water line 73 for introducing cleaning solution from 2 to the first washing tub 101, a sampling device 20 for sampling a portion of the cleaning solution discharged from the third washing tub 103, a concentration estimation device 30 for estimating the effective detergent concentration of the cleaning solution by estimating the surface tension of the cleaning solution sampled by the sampling device 20, a solvent supply mechanism 40 for supplying water to the ninth washing tub 109 from the outside, a chemical injection device 50 for injecting detergent into the cleaning solution stored in the third washing tub 103, and a control device 60 for controlling other components according to the effective detergent concentration estimated by the concentration estimation device 30.

[0048] The washing fluid tanks 101 to 109 are arranged so that the laundry and washing fluid move sequentially through them. In the washing machine 1A shown in the figure, the laundry is placed in the first washing tank 101 and moved in that order from the first washing tank 101 to the ninth washing tank 109 by a transport mechanism (not shown). Meanwhile, the washing fluid is introduced into the first washing tank 101 and the ninth washing tank 109. The washing fluid introduced into the first washing tank 101 has its water volume adjusted in the third washing tank 103 and moves in the same direction as the laundry to the eighth washing tank 108. In addition, some of the washing fluid introduced into the ninth washing tank 109 is carried out to the finishing tank 110 along with the laundry, but basically it moves in the opposite direction to the laundry to the eighth washing tank 108. To maintain the liquid level of the cleaning solution while forming such a flow of cleaning solution, the third washing tub 103 is provided with a drainage overflow section 1031 for discharging excess cleaning solution outside the system, and the eighth washing tub 108 is provided with a recovery overflow section 1081 for recovering excess cleaning solution into the cold water tub 122.

[0049] The first washing tub 101 and the second washing tub 102 are primarily intended for pre-washing, which separates dirt components that can be dissolved into the solvent of the cleaning solution from the laundry even without detergent. The third washing tub 103 to the seventh washing tub 107 are intended for washing, which separates dirt from the laundry using the effect of detergent. The eighth washing tub 108 and the ninth washing tub 109 are intended for rinsing. The finishing tub 110 is intended for the final finishing of the wash by adding souring agents and fabric softeners. The laundry from which the cleaning solution has been separated in the finishing tub 110 may be introduced into a spin dryer or the like (not shown).

[0050] A portion of the washing liquid that overflows from the drain overflow section 1031 of the third washing tub 103 is sampled by the sampling device 20, and its effective detergent concentration is estimated by the concentration estimation device 30. Therefore, the effective detergent concentration estimated by the concentration estimation device 30 is the effective detergent concentration of the washing liquid stored in the third washing tub 103, that is, the washing liquid at the start of the washing process.

[0051] The control device 60 may be configured to control the amount of detergent injected by the chemical injection device 50 so that the effective detergent concentration estimated by the concentration estimation device 30, that is, the estimated effective detergent concentration of the washing solution at the start of the washing process, is within an appropriate range. As a result, even if the effective detergent concentration of the washing solution supplied to the first washing tub 101 from the hot water line 71 and the cold water line 73 fluctuates, the effective detergent concentration of the washing solution at the start of the washing process can be maintained at a constant concentration, thereby maintaining the washing capacity.

[0052] Although various embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications and variations are possible.

[0053] A continuous washing machine having multiple washing tanks may be configured to estimate the effective detergent concentration of the washing water in each washing tank, check the progress of washing, and inject detergent into the necessary washing tanks as needed, using multiple sampling devices provided individually in each washing tank or a shared sampling device connected to the multiple washing tanks in a way that allows for flow switching. In addition, in the washing machine according to the present invention, washing water stored in a hot water tank or washing water flowing through a hot water line may be sampled. Furthermore, in the washing machine according to the present invention, detergent may be injected by an in-line chemical injection device in the hot water line or the like, and the washing water after the detergent injection process may be sampled.

[0054] In the washing machine according to the present invention, in addition to the measured value of the effective detergent concentration, control may be performed taking into account measured values ​​such as turbidity, pH, and electrical conductivity. Furthermore, in the washing machine according to the present invention, the ratio of the amount of overflowed cleaning solution resupplied to the cleaning solution tank and the amount of new solvent supplied to the cleaning solution tank may be adjusted based on the measured value of the effective detergent concentration. In addition, any control method can be adopted for the washing machine according to the present invention, such as on / off control or PID control.

[0055] In the continuous washing machine according to the present invention, the number of washing tubs, the direction of detergent flow, and the discharge position can be appropriately selected based on common technical knowledge. Furthermore, the continuous washing machine according to the present invention may include further configurations, such as a new washing liquid tub for adjusting the effective detergent concentration of the washing solution. In addition, in the continuous washing machine according to the present invention, a drain valve may be provided in each washing liquid tub for quick draining. [Explanation of symbols]

[0056] 1.1A Washing Machine 10,101~109 Washing tub (washing solution tub) 1031 Drain overflow section 1081 Recovery Overflow Section 110 Finishing tank (washing solution tank) 121 Hot water tank (washing solution tank) 122 Cold water tank (washing solution tank) 11 Overflow section 12. Agitator 13 Drain valve 20 Sampling device 30 Concentration estimation device 31 Dilution portion 311 Washing solution metering valve 312 Water volume valve 32. Critical micelle concentration discrimination unit 321 Observation vessel 322 Liquid level detector 33 Effective detergent concentration estimation unit 40 Solvent supply mechanism 41 Water supply valve 50 Chemical dosing device 60 Control device 71 Hot water line 72 rinse water line 73 Cold water line

Claims

1. A cleaning solution tank for storing a cleaning solution containing detergent, A sampling device for sampling the cleaning solution, A concentration estimation device that estimates the effective detergent concentration of the cleaning solution by estimating the interfacial tension of the cleaning solution sampled by the sampling device, A control device that performs control according to the effective detergent concentration estimated by the concentration estimation device, Equipped with, The concentration estimation device includes a dilution unit for diluting the washing solution sampled by the sampling device, A critical micelle concentration determination unit continuously introduces the diluted solution obtained by the dilution unit into an observation container with an open top, causing the diluted solution to overflow from the top opening of the observation container, and determines whether the concentration of free surfactant is less than the critical micelle concentration by checking the height of the liquid surface rise due to surface tension. An effective detergent concentration estimation unit estimates the effective detergent concentration of the cleaning solution based on the dilution ratio of the diluted solution by the dilution unit and the determination result of the critical micelle concentration determination unit, A washing machine.

2. The dilution unit is capable of continuously changing the dilution ratio. The washing machine according to claim 1, wherein the effective detergent concentration estimation unit estimates the effective detergent concentration of the cleaning solution based on the dilution ratio of the dilution solution when it is determined that the concentration of free surfactant in the dilution solution has fallen below the critical micelle concentration.

3. The dilution unit allows for stepwise changes in the dilution ratio. The washing machine according to claim 1, wherein the effective detergent concentration estimation unit estimates that the effective detergent concentration of the cleaning solution is below a concentration category corresponding to the dilution ratio in the dilution unit of the dilution solution when it is determined that the concentration of free surfactant in the dilution solution is less than the critical micelle concentration.

4. The cleaning solution is further provided with a chemical injection device for injecting the detergent, The washing machine according to any one of claims 1 to 3, wherein the control device causes the detergent to be injected into the chemical injection device so as to maintain the effective detergent concentration at or above a predetermined control concentration.

5. The washing machine according to any one of claims 1 to 4, wherein the control device terminates the washing process when it is estimated that the effective detergent concentration has stopped decreasing over time.

6. The washing machine according to any one of claims 1 to 5, wherein a plurality of washing liquid tanks are arranged such that the laundry and the washing liquid move sequentially through each washing liquid tank.

7. The washing machine according to any one of claims 1 to 6, wherein the sampling device samples the cleaning liquid discharged from the cleaning liquid tank or the cleaning liquid that has been treated after being discharged from the cleaning liquid tank.

8. The washing machine according to any one of claims 1 to 7, wherein the control device replaces at least a portion of the cleaning solution in the cleaning solution tank with new cleaning solution when the rate of decrease in the effective detergent concentration of the cleaning solution is greater than a predetermined standard.

9. The process of sampling the cleaning solution, A step of diluting the sampled cleaning solution, The process involves continuously introducing a diluted solution obtained by diluting the cleaning solution into an observation container with an open top, allowing the diluted solution to overflow from the top opening of the observation container, and determining whether the concentration of the free surfactant is less than the critical micelle concentration by checking the height of the liquid surface rise due to surface tension. A step of estimating the effective detergent concentration of the cleaning solution based on the dilution ratio of the diluent and the determination result of whether or not it is less than the critical micelle concentration, A step of managing the washing solution or checking the progress of washing based on the estimated effective detergent concentration, A washing method that includes [the following features].

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