Washing machine with foam detection device and foam detection method

Abstract

The invention discloses a foam detection method of a washing machine, the washing machine is provided with a pH value contrast value of washing water, the pH value of the washing water is acquired for multiple times in the washing process, and after the pH value of the washing water is detected to be stable, the stable pH value is defined as a detection value to be compared with a preset contrast value; the content ratio of the active substances to the water in the washing water is judged according to the comparison result, and the foam generation amount in the washing drum in the washing process is detected, so that a defoaming program suitable for each work of the washing machine is generated, and the defoaming efficiency and the washing efficiency of the washing machine are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of washing machines, and in particular relates to a washing machine with a foam detection device and a foam detection method. Background Art

[0002] In order to improve the problem that too much detergent is added during the washing process of the washing machine, the washing machine cannot effectively detect it, thus affecting the washing efficiency of the washing machine.

[0003] In the prior art, the amount of foam generated by washing water is usually determined by the change of water level value in the washing machine. For example, the invention patent with application number 202310084801.X discloses a rinsing method, device, equipment and medium for a laundry device, wherein a first potential value of the washing machine water level is obtained by a potential sensor, wherein the potential sensor is arranged on the inner side of the outer drum of the laundry device; when the washing procedure is completed and the water is not drained, the second potential value of the current water level is obtained by the potential sensor, wherein the foam content in the washing water in the outer drum is different, and the potential value obtained by the potential sensor is different, and the outer drum is connected to the inner drum of the laundry device for accommodating clothes; the potential difference value is obtained according to the first potential value and the second potential value; and the rinsing procedure is determined according to the potential difference value. However, in this scheme, the amount of foam generated cannot be detected in a timely and accurate manner, which will affect the defoaming efficiency and washing efficiency of the washing machine.

[0004] In addition, there are also existing technologies that determine the amount of foam generated by the washing machine during the washing process by changes in motor speed, power, and the like. For example, the invention patent with application number 202111537468.0 discloses a clothing processing device and its control method, device, and storage medium. The control method includes: in response to the start of dehydration, timing the dehydration operation time, and detecting the motor speed, current, and power during the dehydration process; based on the speed, current, power, and pre-set thresholds detected during the dehydration process, foam detection is performed on the dehydration process. It is possible to detect whether there is too much foam during the dehydration process, but the washing machine needs to distribute the load evenly during dehydration. During this process, the motor speed of the washing machine will continue to change. At this time, the motor speed, power, and other values ​​may also be caused by uneven load distribution, so it is impossible to accurately determine whether the low speed is caused by excessive foam.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The object of the present invention is to provide a foam detection method for a washing machine, wherein the pH value of washing water is obtained multiple times during the washing process of the washing machine, and after the obtained pH value is stabilized, the stabilized pH value is defined as a detection value and compared with a preset control value, and the amount of foam in the washing drum is judged according to the comparison result, and the amount of foam generated in the washing drum is accurately judged according to the ratio of the content of active substances and water in the detection value and the comparison value, so as to formulate a defoaming program that suits each washing and improve the washing efficiency of the washing machine.

[0007] Another object of the present invention is to provide a washing machine provided with a foam detection device for detecting washing water samples, the foam detection device samples the washing water, heats, stirs and filters the washing water to ensure the accuracy of the pH value detection of the washing water.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A foam detection method for a washing machine,

[0010] The pH value of the washing water is obtained multiple times during the washing process. After the pH value is detected to be stable, the stabilized pH value is defined as the detection value and compared with the preset control value. The amount of foam in the washing drum is judged based on the comparison result. The amount of foam in the washing drum is accurately controlled to generate a targeted defoaming program, improve the defoaming efficiency and washing effect of the washing machine, and enhance the user experience.

[0011] Optionally, the pH value is determined to be stable when two consecutively detected pH values ​​satisfy the following relationship:

[0012] |M i -M i-1 | <X

[0013] Where i is the number of detections; M i is the pH value detected for the i-th time during the washing process, and X is a constant;

[0014] Wherein Y is a preset constant, and the pH value stable interval is set by the preset constant. When the absolute value of the difference between two consecutive pH detection values ​​is less than the preset constant, it is determined that the pH value of the washing machine tends to be stable. That is, at this time, the stable value can be used as the detection value for comparison with the control value. According to the comparison result, the ratio of active substances to water in the washing water is determined, thereby accurately calculating the amount of foam generated.

[0015] Optionally, detecting the pH value of the washing water comprises the following steps:

[0016] Sampling of wash water;

[0017] After obtaining the pH value m1, the sample is stirred and the pH value m2 is obtained again;

[0018] The absolute value of the difference between m1 and m2 is less than Y, where Y is a preset constant. Determine whether the sample is evenly obtained and obtain the pH value of the sample. Otherwise, stir again and then obtain the pH value m3, where m j is the number of times of detecting the same sample until |m j -m j-1 |≤Y. Then, obtain the pH value of the sample to ensure that the pH value obtained each time the washing machine stirs the washing water evenly is used as the test value for comparison with the control value, so as to ensure that the obtained test value accurately reflects the proportion of the active substance and water in the washing water.

[0019] Optionally, the value of the preset constant X is 0.1, and the value of the preset constant Y is 0.1.

[0020] Optionally, after determining that the pH value of the washing water is stable, obtain the pH value of the washing water as the test value for comparison with the preset control value. According to the comparison result, judge the proportion of the active substance and water in the liquid in the washing tub, and judge the foam generation amount according to the comparison result; that is, after the start of the washing process of the washing machine and after the mixing of the laundry detergent is basically completed, detect the pH value of the washing water to see if it is stable, and use the detected pH value as the test value for comparison with the control value after determining stability. i -M i-1 |<X, then compare the test value with the control value to judge the proportion of the active substance and water in the washing water.

[0021] The washing machine can detect the pH value of the washing water to see if it is stable after a period of time after the start of the washing process, and use the detected pH value as the test value for comparison with the control value after determining stability.

[0022] Optionally, there is a preset first time interval between two adjacent acquisitions of the pH value of the washing water. When the pH value detected for the i-th time is judged to be stable, at least one more acquisition of M i+1 is performed. When the detected pH value meets |M i -M i-1 |<X and |M i+1 -M i |<X, it is judged that the pH is stable. At this time, use the detected pH value as the test value for comparison with the control value to judge the proportion of the active substance and water in the washing water, and judge the proportion of the active substance and water in the liquid in the washing tub according to the comparison result, so as to judge the foam generation amount.

[0023] After the start of the washing process, the washing machine performs a pH value detection on the washing water every first time interval. When the detected pH value meets |M i -M i-1 |<X and |M i+1 -M iWhen the pH is stable at X, the detected pH value is used as the detected value and compared with the control value to determine the proportion of the active substance and water in the washing water.

[0024] Optionally, when it is determined that the pH of the washing water is stable for the i-th time, at least the average value of M i and M i-1 is used as the detected value. The average value of the pH values detected within the stable range is used as the detected value for comparison with the control value, further reducing errors and ensuring the accuracy of the detection of the active substance in the washing water.

[0025] Optionally, before the washing machine detects the pH value, it obtains the temperature value of the washing water. If the obtained temperature value does not reach the target temperature range, the washing water is heated to the target temperature range before the pH value is detected, which improves the dissolution rate of the laundry detergent in the washing water, also speeds up the reaction rate between the active substance and the stains, improves the detection efficiency, and formulates the defoaming rate faster, thereby improving the washing effect of the washing machine;

[0026] Preferably, the target temperature range is 19 - 21 °C.

[0027] Optionally, before adding the laundry detergent, the washing machine detects the pH value of the clear water, and uses the detected pH value of the clear water as the control value to ensure the accuracy of the control value and reduce the detection error.

[0028] Optionally, a foam detection device for detecting the washing water sample is provided inside the washing machine. The foam detection device includes:

[0029] A detection chamber with an electrode for detecting the pH of the washing water inside;

[0030] A stirring device provided in the detection chamber;

[0031] A filtering device;

[0032] A sampling module for extracting the washing water;

[0033] The washing water extracted by the sampling module enters the detection chamber after being filtered by the filtering device.

[0034] The present invention has at least the following beneficial effects:

[0035] 1. By comparing and analyzing the control value and the detected value, the present invention determines the proportion of the active substance and water in the washing water during the washing process of the washing machine. According to the proportion of the active substance and water in the water, the amount of foam generated in the washing tub during the washing process is analyzed, and thus a corresponding defoaming strategy is generated according to the amount of foam generated, improving the washing efficiency during the washing process.

[0036] 2. In the present invention, the collected sample is stirred, and the pH values ​​m1 and m2 are obtained before and after stirring. When the absolute value of the difference between m1 and m2 is ensured to be less than the set value, that is, after the laundry detergent is completely mixed in the washing water, the detected data is used as the data for judging the pH value of the washing water, thereby ensuring the stability of the detection result and improving the accuracy of the foam detection method.

[0037] 3. The present invention starts to obtain the pH value of the washing water after the washing process of the washing machine begins. When the pH value of the washing water is obtained twice in succession, there is a preset first time interval between them, to ensure that the detection value when the pH value of the washing water tends to be stable can be detected at the earliest, and the detection value is compared with the control value to obtain the content ratio of active substances and water in the washing water, so as to predict the amount of foam generated, and generate a corresponding defoaming strategy according to the amount of foam generated, so as to further improve the efficiency of foam detection and enhance the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 1. Foam detection device; 11. Sampling module; 12. Stirring device; 13. Filtering device; 14. Detection chamber; 141. Electrode.

[0039] Figure 1 It is an overall flow chart of the foam detection method of the present invention;

[0040] Figure 2 This is a flow chart of obtaining the pH value of washing water according to the present invention;

[0041] Figure 3 A flow chart of obtaining detection values ​​for the foam detection method of the present invention;

[0042] Figure 4 This is a flow chart of the foam detection method described in Embodiment 2 of the present invention;

[0043] Figure 5 Schematic diagram of the foam detection device of the present invention. DETAILED DESCRIPTION

[0044] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Those skilled in the art will appreciate that the following embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0045] In the description of the present invention, unless otherwise clearly specified and limited, the terms "setting" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0046] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0047] The present invention discloses a foam detection method for a washing machine. Figure 1 As shown, the washing machine is provided with a pH control value of the washing water, and obtains the pH value of the washing water multiple times during the washing process. After detecting that the pH value of the washing water is stable, the stabilized pH value is defined as the detection value and compared with the preset control value. The content ratio of active substances and water in the washing water is judged according to the comparison result, and the amount of foam generated in the washing drum during the washing process is detected, so as to generate a defoaming program adapted to each operation of the washing machine, thereby improving the defoaming efficiency and washing efficiency of the washing machine.

[0048] Next, the present invention is described in detail with reference to specific embodiments.

[0049] Embodiment 1

[0050] As an embodiment of this embodiment, in this embodiment, if Figure 1 , Figure 2 , Figure 3 As shown, the washing machine is provided with a pH control value of the washing water; the pH value of the washing water is obtained multiple times during the washing process of the washing machine. After the pH value is detected to be stable, the stable pH value is defined as the detection value and compared with the preset control value, and the amount of foam in the washing drum is judged according to the comparison result.

[0051] Furthermore, the washing machine determines the ratio of active substances and water in the washing water in the drum during washing according to the comparison results of the detection value and the control value, and determines the amount of foam generated during the washing process according to the ratio of active substances to water, thereby achieving more accurate detection effects, improving washing effects, and user experience.

[0052] Furthermore, when the deviation between the control value and the test value is not large, it means that the degree of combination of detergent and clothes is good, and a large amount of foam will not be generated during the washing process of the washing machine, which will not affect the cleaning of clothes; when the deviation between the control value and the test value is large, it is judged whether the detergent is excessive or insufficient, and detergent is added when it is insufficient; when the detergent is excessive, the defoaming program is started.

[0053] Further, the following relationship is satisfied according to the detected pH value:

[0054] |M i -M i-1|<X

[0055] where i is the number of detections; M i is the pH value detected at the i-th time during the washing process, X is a constant;

[0056] Judge the stability of the pH value. Set the stable range of the pH value through a preset constant. When the absolute value of the difference between two consecutive pH detection values is less than the preset constant, it is determined that the pH value of the washing machine tends to be stable. That is, at this time, the stable value can be used as the detection value for comparison with the control value. According to the comparison result, the ratio of the active substance to water in the washing water is determined, so as to accurately calculate the amount of foam generated.

[0057] Furthermore, in order to ensure that the laundry detergent in the washing water is fully and evenly mixed every time the pH value is detected, that is, the pH value obtained each time is the actual state of the washing water, detecting the pH value of the washing water includes the following steps:

[0058] Sample the washing water;

[0059] After obtaining the pH value m1, stir the sample, and then obtain the pH value m2 again;

[0060] If the absolute value of the difference between m1 and m2 is less than Y, it is judged that the sample is uniform and the pH value of the sample is obtained. Otherwise, stir again and then obtain the pH value m3 until |m j -m j-1 |<Y, then obtain the pH value of the sample, ensuring that the pH value obtained by the washing machine for the washing water after being stirred evenly each time is used as the detection value for comparison with the control value, and ensuring that the obtained detection value accurately reflects the proportion of the active substance and water in the washing water.

[0061] As a specific implementation manner of the present invention, as Figure 5 shown, the washing machine includes a foam detection device 1. The foam detection device 1 is used to detect the pH value of the washing water in the washing tub. The steps for the foam detection device 1 to obtain the washing water are as follows: After extracting the washing water in the washing tub, first detect the pH value of the mixed liquid to obtain m1, and then stir the extracted mixed liquid. After stirring for a set time, perform a second pH value detection on the washing water to obtain m2. If the laundry detergent in the mixed liquid is dissolved sufficiently, the pH values of m1 and m2 differ very little and are within the set error range. At this time, m2 is used as the pH value M of the washing water obtained during the washing process. Obtain the pH value M of the washing water multiple times, sample and detect the washing water multiple times, and obtain several pH values including M1, M2, etc. When the detected pH value satisfies |M i -M i-1 |<X, it is determined that the pH value M i and M i-1 are stable values, M i and M i-1Both can be used as test values ​​for comparison with control values, and the proportion of active substances and water in the liquid in the drum during washing can be determined based on the comparison results, thereby determining the amount of foam generated.

[0062] Furthermore, M i With M i-1 The average value is used as the test value M for comparison with the control value to further enhance the accuracy of the test results.

[0063] Further, such as Figure 2 As shown, if the pH value difference between m1 and m2 is large, the washing water in the foam detection device 1 continues to be stirred. After the stirring time is set, the pH value of the washing water is tested for the third time to obtain m3. If the laundry detergent in the mixed liquid is fully dissolved, the pH value difference between m2 and m3 is very small, and is within the set error range. At this time, the pH value of the washing water obtained during the washing process of m3 is M.

[0064] Furthermore, if the difference between the values ​​of m2 and m3 is still large, the above detection steps are repeated until the last two detection values ​​are within the set error range. It is well known to those skilled in the art that the dissolution time of laundry detergent in water does not need to be very long. Under the premise that the foam detection device 1 stirs the mixed liquid, the pH value M of the washing water can be obtained by detecting 2 to 3 times.

[0065] Specifically, as a specific implementation of this embodiment, when Y is 0.1, that is, m i With m i-1 When the absolute value of the difference is less than 0.1, it is determined that the laundry detergent is completely dissolved in the water. j is the number of times the same sample is tested.

[0066] Furthermore, in order to improve the detection speed of the foam detection device 1 and improve the detection efficiency while ensuring the accuracy of the detection results, the washing machine first detects the temperature of the washing water before detecting the pH value. If the temperature does not reach the target temperature, the washing water is heated. After detecting that the water temperature reaches the target temperature, the pH value is detected. The water temperature of the washing water at this time has a better dissolution rate for the laundry detergent, thereby optimizing the detection time of the foam detection device 1, and increasing the washing machine After determining the test result, there is more reaction time to add laundry detergent, or start the defoaming program, thereby improving the washing effect and washing efficiency of the washing machine.

[0067] Specifically, in the present embodiment, the target temperature includes a target range, and the target range is 19° C. to 21° C. At this time, the dissolution efficiency of the laundry detergent in the washing water is high, which is beneficial to improving the dissolution efficiency of the laundry detergent, thereby improving the foam detection efficiency.

[0068] Furthermore, in order to improve the accuracy of pH value detection, the foam detection device 1 includes a filtering device 13. The filtering device 13 will filter the washing water before the washing water enters the foam detection device 1. On the one hand, it will increase the degree of fusion between the laundry detergent and the washing water during the filtering process. On the other hand, it will filter out impurities in the washing water to prevent the pH value of the washing water from being affected by impurities in the water when detecting the pH of the washing water, thereby further improving the accuracy of the detection and preventing debris and impurities in the washing water from damaging the foam detection device 1, thereby increasing the practical life of the foam detection device 1.

[0069] As a specific implementation of this embodiment, Figure 5 As shown, a foam detection device 1 for detecting a washing water sample is provided inside the washing machine, and the foam detection device 1 comprises:

[0070] The detection chamber 14 is provided with an electrode 141 for detecting the pH of the washing water;

[0071] A stirring device 12 is disposed in the detection chamber 14;

[0072] Filter device 13;

[0073] A sampling module 11, used for extracting washing water;

[0074] The washing water extracted by the sampling module 11 enters the detection chamber 14 after being filtered by the filtering device 13 .

[0075] Specifically, the foam detection device 1 includes a peristaltic pump module, a filter device 13, a stirring device 12, a detection chamber 14, and an electrode 141. The washing water is sucked by the peristaltic pump module, and after being filtered by the filter device 13, the washing water enters the detection chamber 14. The detection chamber 14 first detects the water temperature of the washing water. When the water temperature is detected to be lower than 19°C, the stirring device 12 starts to operate to heat the washing water. After heating for a period of time, the water temperature is detected to be higher than 19°C. At this water temperature, the washing water has a high solubility in the laundry detergent and a fast dissolution speed. Then, the electrode 141 detects the pH value of the washing water to obtain m 1, and then the washing water is stirred. In this embodiment, the stirring device 12 runs for 30 seconds to ensure that the laundry detergent can be fully dissolved. After the stirring device 12 ends, the electrode 141 performs a pH test on the washing water again to obtain m2. The foam detection device 1 sends the measured values ​​of m1 and m2 to the processor of the washing machine. The processor compares the values ​​of m1 and m2. When the difference between the absolute values ​​of m1 and m2 is greater than 0.1, the stirring device 12 continues to run for 30 seconds, and the pH motor performs a pH test on the washing water again to obtain m3. The values ​​of m2 and m3 are compared until m j With m j-1 The absolute value of the difference is less than 0.1, then m jThe value is used as the pH value M of the washing water at one time, and the pH value of the washing water is obtained multiple times, M1, M2...M i , when the pH value of the washing water detected twice is M i With M i-1 When the absolute value of the difference is less than 0.1, M i The value is used as the test value and compared with the control value. The proportion of active substances and water in the washing water is determined according to the comparison result. When the content of active substances is greater than the content of water, the washing machine starts the defoaming program to defoam; when the content of active substances is less than the content of water, you can choose to add detergent to ensure the washing effect of the washing machine on clothes.

[0076] Embodiment 2

[0077] As an embodiment of the present invention, this embodiment further describes the control value determination method of the foam detection device 1 based on the first embodiment, as follows:

[0078] In the first embodiment, the foam detection method detects the washing water after the washing machine starts the washing process for a period of time. Figure 4 As shown, after washing starts, the foam detection device 1 detects the washing water at regular intervals. When it is detected that the washing water is evenly mixed, the pH value of the evenly mixed washing water is used as the detection value to be compared with the control value, thereby improving the detection efficiency of the foam detection device 1.

[0079] Furthermore, a preset first time period is set between two consecutive acquisitions of the pH value of the washing water.

[0080] Furthermore, after the washing machine starts washing for a period of time, the foam detection device 1 extracts washing liquid in the washing drum at regular intervals to detect the pH value. After detecting the value of M2, the foam detection device 1 discharges the washing liquid in the detection chamber 14, and extracts washing water from the washing drum again, repeats the temperature detection of the washing water, stirs, samples and detects the washing water multiple times, and obtains several pH values ​​including M1 and M2, until the pH value tends to be stable. At this time, the active substances in the laundry liquid in the washing drum react with the stains. At this time, the stabilized pH value is compared with the control value. According to the comparison result, the content ratio of the active substances and water in the washing water is obtained, and a corresponding defoaming strategy is formulated according to the ratio.

[0081] Through the detection value determination method in this embodiment, while ensuring the accuracy of the detection value M, it is also guaranteed that the detection value is obtained in the fastest time, further improving the efficiency of the foam detection method, thereby ensuring that the washing machine formulates a defoaming strategy more quickly, improving the cleaning efficiency of the washing machine during the washing process, and enhancing the user experience.

[0082] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content suggested above without departing from the scope of the technical solution of the present invention. The implementation scheme in the above embodiment can also be further combined or replaced. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the solution of the present invention.

Claims

1. A foam detection method for a washing machine, characterized in that: The pH value of the washing water is obtained multiple times during the washing process. After the pH value is detected to be stable, the stable pH value is defined as the detection value and compared with the preset control value, and the amount of foam in the washing drum is determined based on the comparison result.

2. A foam detection method for a washing machine according to claim 1, characterized in that: When the pH values ​​detected twice consecutively satisfy the following relationship, the pH value is considered stable: |M i -M i-1 |<X Where i is the number of detections; M i is the pH value detected for the i-th time during the washing process, and X is a preset constant.

3. A foam detection method for a washing machine according to claim 2, characterized in that: Testing the pH value of washing water includes the following steps: Sampling of wash water; After obtaining the pH value m1, the sample is stirred and the pH value m2 is obtained again; The absolute value of the difference between m1 and m2 is less than Y, and it is judged that the sample is uniform and the pH value of the sample is obtained. Otherwise, stir again and then obtain the pH value m3 until |m j -m j-1 |<Y, and then obtain the pH value of the sample; Among them, m j is the number of times the same sample is tested, and Y is a preset constant.

4. The foam detection method for a washing machine according to any one of claims 2 or 3, characterized in that: The value of the preset constant X is 0.1, and the value of the preset constant Y is 0.

1.

5. A foam detection method for a washing machine according to claim 2, characterized in that: After determining that the pH value of the washing water is stable, the pH value of the washing water is obtained as a detection value and compared with a preset control value. The proportion of the active substance and water in the liquid in the washing drum is determined based on the comparison result, thereby determining the amount of foam generated.

6. A foam detection method for a washing machine according to claim 2, characterized in that: The first time interval between two consecutive acquisitions of the pH value of the washing water is preset. The pH value detected for the i-th time is judged to be stable. After the first time interval, M is acquired again. i+1 ,|M i -M i-1 |≤X if |M i+1 -M i |≤X indicates that pH is stable.

7. The foam detection method for a washing machine according to any one of claims 5 or 6, characterized in that: In the i-th time, the pH of the washing water is judged to be stable, at least M i and M i-1 The average value is taken as the detection value.

8. A foam detection method for a washing machine according to any one of claim 1, characterized in that: Before detecting the pH value, the temperature value of the washing water is obtained. If the obtained temperature value does not reach the target temperature range, the washing water is heated to the target temperature range and then the pH value is detected; Preferably, the target temperature range is 19-21°C.

9. The foam detection method of a washing machine according to claim 1, characterized in that: Before adding laundry detergent to the washing machine, the pH value of the clean water is tested and the detected pH value of the clean water is used as a control value.

10. A washing machine using the foam detection method according to any one of claims 1 to 9, characterized in that A foam detection device for detecting washing water samples is provided inside the washing machine, and the foam detection device includes: A detection chamber (14) is provided with an electrode (141) for detecting the pH value of washing water; A stirring device (12) is arranged in the detection chamber (14); Filter device (13); A sampling module (11) for extracting washing water; The washing water extracted by the sampling module (11) is filtered by the filtering device (13) and then enters the detection chamber (14).

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