Water level detection method and dishwasher

Abstract

The present invention relates to the technical field of dishwashers, and discloses a water level detection method and a dishwasher. The water level detection method comprises: using a water level sensor to detect the water level frequency of the inner tank, judging whether the water intake of the inner tank is abnormal, whether there is a drainage fault or an overflow fault based on the detected water level frequency, and if the water intake of the inner tank is abnormal or there is a drainage fault or an overflow fault, the main control board issues an alarm prompt. The dishwasher uses the above-mentioned water level detection method to detect the water level of the inner tank. The present invention can detect excessive or insufficient water intake and overflow faults in the water intake procedure, as well as drainage faults in the drainage procedure, so as to remind the user to repair in time. Compared with the temperature and turbidity sensor, frequency conversion board and flow meter in the prior art, the water level sensor of the present invention is installed on the outside of the inner tank, which is easy to install, not easy to be contaminated, has a long service life, reliable detection results, and is low in cost, comprehensive in function and highly versatile.

Description

Technical Field

[0001] The present invention relates to the technical field of dishwashers, and in particular to a water level detection method and a dishwasher. Background Art

[0002] During dishwasher use, the drain pump may break, the drain hose may become compressed or bent, the sink filter may become clogged due to long-term cleaning, or the internal pipes may become blocked. This can prevent water from draining properly from the dishwasher during the wash cycle. Furthermore, the water inlet valve or flow meter may become damaged, causing the dishwasher to continuously fill with water. Therefore, during dishwasher use, it is necessary to monitor abnormalities in drainage, water inflow, and overflow in real time.

[0003] Dishwashers with non-variable frequency motors often use temperature and turbidity sensors to detect abnormal drainage. However, since these sensors are in direct contact with the water and rely on light scattering for detection, they can easily become dirty over time, leading to inaccurate detection. Furthermore, these sensors are relatively expensive. Dishwashers with variable frequency motors often use power to detect abnormal drainage. However, these require a corresponding inverter board, which is more expensive than non-variable frequency motors. Flow meters are often used to detect water inflow, but these meters are costly, limited in functionality, lack versatility, and have low reliability. Summary of the Invention

[0004] Based on the above, the purpose of the present invention is to provide a water level detection method and a dishwasher with low cost and high reliability, which can detect the water level in both the water inlet process and the water drain process.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A water level detection method uses a water level sensor to detect the water level frequency of an inner tank, and determines whether the water inflow into the inner tank is abnormal, whether there is a drainage fault or overflow fault based on the detected water level frequency. If the water inflow into the inner tank is abnormal, or there is a drainage fault or overflow fault, the main control board will issue an alarm prompt.

[0007] As a preferred solution of a water level detection method, in a drainage procedure, the water level detection method includes:

[0008] S11: The drainage pump starts to drain water, and the drainage pump is turned off after a set time;

[0009] S12: The water level sensor detects the current water level frequency value f;

[0010] S13: Compare the current water level frequency value f with the calibrated empty bucket frequency lower limit f3. If f<f3, execute step S14; if f≥f3, execute step S16.

[0011] S14: Determine whether the number of times f<f3 reaches N1 times continuously. If so, execute step S15; if not, return to step S11;

[0012] S15: The drainage pump continues to drain water, and the main control board issues a drainage failure alarm;

[0013] S16: The drainage process ends.

[0014] As a preferred solution of a water level detection method, in the water inlet procedure, the water level detection method includes:

[0015] S21: The water inlet valve starts to let water in, and the water inlet valve closes after a set time;

[0016] S22: The water level sensor detects the current water level frequency value f;

[0017] S23: Compare the current water level frequency value f with the calibrated normal frequency lower limit f1 and normal frequency upper limit f2. If f1 < f < f2, execute step S28; if f > f2, execute step S24.

[0018] S24: Determine whether the number of times f>f2 reaches N2 times continuously. If so, the main control board issues a water shortage fault alarm. If not, the drainage pump drains for a set time and returns to step S21.

[0019] S28: The water inlet procedure ends.

[0020] As a preferred solution of the water level detection method, step S23 further includes: if f<f1, executing the following steps:

[0021] S25: Compare the current water level frequency value f with the calibrated overflow frequency upper limit f4. If f<f4, execute step S27; if f1>f>f4, execute step S26.

[0022] S26: Determine whether the number of times f1>f>f4 reaches N3 times continuously. If so, the drain pump is turned on and the main control board issues an excessive water inflow alarm. If not, detect whether there is a drainage fault. If there is a drainage fault, the drain pump starts to drain continuously and reports a drainage fault. If there is no drainage fault, return to step S21.

[0023] S27: The drainage pump continues to drain water, and the main control board issues a water overflow fault alarm.

[0024] As a preferred solution of a water level detection method, in the water inlet procedure, the water level detection method further includes: before executing step S21, first detecting whether there is a drainage fault.

[0025] As a preferred solution of a water level detection method, in step S11 and step S24, the drainage pump adopts intermittent drainage, and the drainage time is set to 1 minute. The drainage pump cycles 4 times in the manner of opening for 10 seconds and pausing for 5 seconds.

[0026] As a preferred solution of a water level detection method, in step S15 and step S27, the drainage pump continuously drains water in a manner that the drainage pump operates in a cycle of being turned on for 30 seconds and turned off for 15 seconds.

[0027] As a preferred solution of a water level detection method, the value ranges of N1, N2 and N3 are: N1≥2, N2≥2, N3≥2.

[0028] As a preferred solution of a water level detection method, the water inlet program and the water discharge program include water inlet subprograms and water discharge subprograms involved in a pre-wash stage, a main wash stage, a cold rinse stage, and a hot rinse stage.

[0029] As a preferred solution of a water level detection method, the main control board issues an alarm by flashing indicator lights and / or voice broadcasting and / or text display.

[0030] A dishwasher uses the water level detection method described in any of the above schemes to detect the water level in the inner tank. The dishwasher includes a water level sensor and a water tank. The water level sensor is installed on the outside of the inner tank. The water level sensor can detect the water level pressure in the inner tank and convert the pressure signal into a frequency signal to feed back to the main control board. The water tank is provided with a chamber, and the water level sensor is connected to the chamber via a pressure conduit.

[0031] The beneficial effects of the present invention are:

[0032] The present invention uses a water level sensor to detect the water level frequency of the dishwasher's inner tank, ensuring that the water level is within a set frequency threshold range to ensure that the water level in the dishwasher's inner tank is within a normal range. When the actual water level frequency of the inner tank exceeds the set frequency threshold range, the main control board issues an alarm, indicating abnormal water inflow, overflow, or drainage failure. Therefore, the present invention not only prevents excessive or insufficient water inflow and overflow caused by water inlet valve failure during the water inflow process, but also prevents drainage failures caused by damage to the drain pump or drain pipe during the drainage process. Compared to the temperature and turbidity sensors, frequency converters, and flow meters in the prior art, the water level sensor of the present invention is installed on the outside of the inner tank. It is easy to install, not easily contaminated, has a long service life, provides reliable detection results, is relatively low in cost, has comprehensive functions, and is highly versatile. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a water level detection method for a drainage program provided by an embodiment of the present invention;

[0034] Figure 2 This is a flow chart of a water level detection method for a water inlet procedure provided by an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the connection between the water tank and the water level sensor of the dishwasher provided by the embodiment of the present invention. Figure 1 ;

[0036] Figure 4 This is a schematic diagram of the connection between the water tank and the water level sensor of the dishwasher provided by the embodiment of the present invention. Figure 2 ;

[0037] Figure 5 1 is a top view of a water tank and a water level sensor of a dishwasher provided in an embodiment of the present invention.

[0038] In the picture:

[0039] 100-water sink; 110-chamber; 101-water diversion valve interface; 102-top spray water interface; 103-water inlet valve interface; 104-drain pipe interface; 105-drain pump interface; 106-washing motor first interface; 107-washing motor second interface; 108-bottom spray outlet; 109-water level sensor interface; 200-pressure conduit; 300-water level sensor. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0041] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0042] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0043] In the description of this embodiment, the terms "upper," "lower," "left," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0044] like Figure 1-Figure 2 As shown, this embodiment provides a water level detection method for detecting abnormal water inflow, drainage failure, and overflow failures in household appliances such as dishwashers and washing machines during use. Specifically, this embodiment uses a dishwasher as an example. The water level detection method includes: using a water level sensor to detect the water level frequency of the inner tank; based on the detected water level frequency, determining whether the inner tank has abnormal water inflow, drainage failure, or overflow failure; if the inner tank has abnormal water inflow, drainage failure, or overflow failure, the main control board issues an alarm.

[0045] This embodiment uses a water level sensor to monitor the water level frequency within the dishwasher's inner tank in real time, ensuring the frequency is within a set frequency threshold to maintain the water level within the normal range. When the actual water level frequency within the tank exceeds the set frequency threshold, the main control board issues an alarm, indicating abnormal water inflow, overflow, or drainage failure. Therefore, this embodiment not only prevents excessive or insufficient water inflow, or overflow, caused by a failed water inlet valve during the water inlet process, but also prevents drainage failures caused by damage to the drain pump or drain pipe during the drainage process. Compared to conventional temperature and turbidity sensors and flow meters, the water level sensor of this embodiment is installed on the outside of the inner tank, offering easy installation, a long service life, reliable detection results, low cost, comprehensive functionality, and strong versatility.

[0046] Specifically, the water level sensor in this embodiment detects the water pressure in the dishwasher's inner tank and converts the detected pressure signal into a frequency signal, which is then fed back to the dishwasher's main control board. This signal is then compared with a water level frequency reference value stored within the control board to determine whether the water level in the inner tank is normal. Therefore, before using the water level sensor for detection, each water level in the inner tank must be calibrated so that each water level corresponds to a specific water level frequency value.

[0047] In this embodiment, the process for calibrating the inner tank water level is as follows: First, assemble the dishwasher with the water level sensor according to the final design. Then, connect a data acquisition device that converts the pressure measured by the water level sensor into a frequency value for reading by the main control board. Next, use a highly accurate measuring device such as a graduated cylinder or dropper to gradually add water to the inner tank to collect data. During calibration, first calibrate the empty tank water level. Start the dishwasher with the tank empty. Take multiple measurements and average them to determine the lower limit of the empty tank frequency, f3. Then, add 10ml of water to the inner tank (this value can be adjusted to suit different dishwasher types). The frequency corresponding to each water level is measured (each frequency value is averaged over multiple measurements). These measured water level frequencies include a normal lower limit, f1, and a normal upper limit, f2. The inner tank water level is considered normal within the range of f1 and f2. As the water level continues to rise until it reaches the tank's maximum capacity, the upper limit of the overflow frequency, f4, is measured (averaged over multiple measurements). In this embodiment, since water level pressure is inversely proportional to its corresponding frequency value, the pressure is lowest and the water level frequency is highest when the drum is empty; the pressure is highest and the water level frequency is lowest when overflowing; in other words, f3>f2>f1>f4. Once the above-mentioned reference water level frequency value is determined, it can be universally applied to all dishwashers of that model, provided the installation method remains unchanged, eliminating the need for individual calibration. In this embodiment, since this calibration method measures each 10ml of water added, it offers high detection accuracy. Each water level corresponds to a water level frequency value, thus replacing the current method of measuring water level using flow meters or temperature-turbidity sensors, achieving precise control of the water level within the dishwasher.

[0048] Specifically, if Figure 1 As shown, when the water level detection method of this embodiment is used in a drainage procedure, it includes the following steps:

[0049] S11: The drain pump starts draining and shuts down after the set time.

[0050] In this step, the drain pump preferably uses intermittent drainage, meaning it operates for a period of time, pauses for a period of time, and then shuts down after several cycles of continuous drainage. Preferably, the timer in this step is set to 1 minute, with the drain pump cycling through four cycles of 10-second on and 5-second pause. It should be noted that the drainage program in this embodiment includes drainage subroutines associated with each wash process, including the pre-wash phase, main wash phase, cold rinse phase, and hot rinse phase. Therefore, the drain pump's drainage time can be set according to actual needs in different wash processes.

[0051] S12: The water level sensor detects the current water level frequency value f;

[0052] Specifically, the water level sensor detects the water level pressure in the inner tank, converts the detected pressure signal into a frequency signal, and feeds it back to the main control board.

[0053] S13: Compare the current water level frequency value f with the calibrated empty bucket frequency lower limit f3. If f<f3, execute step S14; if f≥f3, execute step S16.

[0054] In this embodiment, after the drain pump is turned off, the current water level frequency f in the inner tank is collected and compared with the lower limit of the empty tank frequency f3 stored in the main control board to determine whether the previous drainage was complete and whether there is residual water in the inner tank. If f < f3, it indicates that there is residual water in the inner tank; if f ≥ f3, the water in the inner tank has been drained and the previous drainage was normal.

[0055] S14: Determine whether the number of times f<f3 reaches N1 times continuously. If so, execute step S15; if not, return to step S11;

[0056] In this step, after detecting the presence of residual water in the inner tank, multiple tests are performed to prevent detection errors, thereby ensuring more accurate test results and preventing false alarms. In this embodiment, N1 ≥ 2, and preferably, N1 is 3. That is, if f < f3 is detected three times in a row, the dishwasher is determined to have a drainage malfunction. If f < f3 is detected less than three times, there may be a detection error. Therefore, the drain pump is restarted to drain the water, and after a set time, the drain pump is turned off, and then f is tested again to see if it is less than f3.

[0057] S15: The drain pump continues to drain water, and the main control board issues a drainage failure alarm;

[0058] If a drainage malfunction is detected, the drain pump remains on to prevent residual water from accumulating and potentially affecting the next use. The drain pump preferably operates in a cycle of 30 seconds on and 15 seconds off. During this step, the main control panel issues an alarm to alert the user that a drainage malfunction has occurred, possibly due to a clogged drain pipe or damaged drain pump. The user can wait for repairs. The main control panel's alarm can also include a flashing indicator light, voice announcement, and / or text display.

[0059] S16: The drainage process ends.

[0060] After detecting f≥f3, it means that the water in the inner tank has been drained and there is no residual water. The dishwasher's drainage function is normal, so the subsequent washing process can be carried out after the drainage program is completed.

[0061] like Figure 2 As shown, when the water level detection method of this embodiment is used in a water inlet procedure, the following steps are included:

[0062] S21: The water inlet valve starts to flow in, and after the set time, the water inlet valve closes;

[0063] In this step, the water inlet valve is opened for a set time. Under normal circumstances, the water intake should remain within a certain range. If it is not within this range, it indicates that there may be a problem with the water intake process. It should be noted that the water intake process of this embodiment also includes water intake subroutines related to various washing processes, such as the pre-wash stage, main wash stage, cold rinse stage, and hot rinse stage. Because the water intake requirements vary in different washing processes, the water inlet valve opening time can be set according to actual needs.

[0064] S22: The water level sensor detects the current water level frequency value f;

[0065] In this embodiment, the frequency f of the current water level in the inner tank is collected after the water inlet valve is closed, which can be used to detect whether the water intake within the set time of the dishwasher is normal. Therefore, this embodiment can determine whether the dishwasher is receiving water normally based on the water inlet time of the water inlet valve and the water level frequency detected by the water level sensor.

[0066] S23: Compare the current water level frequency value f with the calibrated normal frequency lower limit value f1 and normal frequency upper limit value f2. If f1 < f < f2, execute step S28; if f > f2, execute step S24; if f < f1, execute step S25;

[0067] In this step, if f1 < f < f2, the water intake is within the normal range, and the dishwasher can proceed to the next step. If f > f2, the dishwasher is considered to have insufficient water intake, possibly due to a clogged water inlet valve or a leak. However, since a single test result is not always accurate, further testing is necessary. If f < f1, the dishwasher is considered to have excessive water intake, possibly due to residual water in the inner tank, which also requires further testing.

[0068] S24: Determine whether the number of times f>f2 reaches N2 times continuously. If so, the main control board issues a water shortage fault alarm. If not, the drainage pump drains for a set time and returns to step S21;

[0069] In this embodiment, N2≥2, and preferably, the value of N2 is 3. That is to say, when f>f2 is detected for three consecutive times, it is determined that the dishwasher has a problem of insufficient water intake, and the main control board alarms to prompt the user to perform maintenance in time. In this step, multiple detections can make the detection results more accurate and prevent false alarms. When the number of times f>f2 does not reach 3 times, there may be a detection error, so the drain pump is restarted to drain the water (note that this drainage process does not require drainage fault detection), the drain pump is turned off after the set time, and then water is refilled, and it is detected again whether f is greater than f2. In this step, the drain pump also uses intermittent drainage, and the drainage time is set to 1 minute. The drain pump cycles 4 cycles of turning on for 10 seconds and pausing for 5 seconds. The main control board can alarm by flashing indicator lights and / or voice broadcasts and / or text displays, etc.

[0070] S25: Compare the current water level frequency value f with the calibrated overflow frequency upper limit f4. If f<f4, execute step S27; if f1>f>f4, execute step S26.

[0071] When it is detected that the dishwasher has too much water intake, it is necessary to first determine whether the water level at this time has reached the overflow level of the dishwasher. If f<f4, it means that the water level at this time has reached the overflow level and needs to be dealt with in time; if f1>f>f4, it means that although the water intake is large, it has not yet reached the overflow level. There may be a detection error and further detection and confirmation is required.

[0072] S26: Determine whether the number of times f1>f>f4 reaches N3 times consecutively. If so, the drain pump is turned on and the main control board issues an excessive water inflow alarm. If not, check whether there is a drainage fault. If there is a drainage fault, the drain pump starts to drain continuously and reports a drainage fault. If there is no drainage fault, return to step S21.

[0073] In this embodiment, N3≥2, and preferably, the value of N3 is 3. That is to say, when f1>f>f4 is detected for three consecutive times, it is determined that the dishwasher has a problem of excessive water intake, and the main control board alarms to prompt the user to perform maintenance in time. In this step, multiple detections can make the detection results more accurate and prevent false alarms. When the number of times f1>f>f4 does not reach three times, there may be a detection error, so it is necessary to drain the water again to detect whether there is a drainage fault (i.e., steps S11-S16) to see if the detection error is caused by the last drainage not being completed. If so, the main control board will issue a drainage fault alarm. If not, after the drainage is completed, it returns to step S21, refills the water, and detects again. In this step, the main control board can make an alarm by flashing indicator lights and / or voice broadcast and / or text display.

[0074] S27: The drain pump continues to drain water, and the main control board issues an overflow fault alarm.

[0075] When f < f4, the water level has reached the overflow level, exceeding the dishwasher's maximum capacity. Therefore, the main control board immediately issues an overflow alarm, eliminating the need for repeated testing. Simultaneously, the main control board activates the drain pump to continuously drain the water. This continuous draining process involves cycling between 30-second on and 15-second off. The main control board can issue an overflow alarm through a flashing indicator light, voice announcement, or text display.

[0076] S28: The water inlet procedure ends.

[0077] Preferably, the water filling procedure further includes: before executing step S21, first detecting whether there is a drainage failure (i.e., steps S11 to S16) to detect whether there is drainage residue from the previous procedure. Of course, this does not mean that it is necessary to perform the test in every water filling procedure, and the need for the test can be determined based on actual conditions.

[0078] like Figure 3-Figure 5As shown, this embodiment also provides a dishwasher that uses the above-mentioned water level detection method to detect the water level in the inner tank. The dishwasher includes a water level sensor 300 and a water tank 100, wherein the water level sensor 300 is installed on the outside of the inner tank. The water level sensor 300 can detect the water level pressure in the inner tank and convert the pressure signal into a frequency signal to feed back to the main control board. The water tank 100 is provided with a chamber 110. The chamber 110 has a water diversion valve interface 101, a top spray water channel interface 102, a water inlet valve interface 103, a drain pipe interface 104, a drain pump interface 105, a first washing motor interface 106, a second washing motor interface 107, and a bottom spray outlet 108, which are respectively used to connect to the water diversion valve, the top spray water channel, the water inlet valve, the drain pipe, the drain pump, one port of the washing motor, another port of the washing motor, and the bottom spray pipeline. The above structure is not the focus of the present invention and will not be described in detail in this embodiment. In this embodiment, the chamber 110 further has a water level sensor interface 109 , and the water level sensor 300 is connected to the water level sensor interface 109 via a pressure conduit 200 , thereby achieving communication between the water level sensor 300 and the chamber 110 .

[0079] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A water level detection method, characterized in that: A water level sensor is used to detect the water level frequency of the inner tank. Based on the detected water level frequency, it is determined whether the water inflow of the inner tank is abnormal, whether there is a drainage fault or an overflow fault. If the water inflow of the inner tank is abnormal, or there is a drainage fault or an overflow fault, the main control board will issue an alarm. In the water inflow procedure, the water level detection method includes: S21: The water inlet valve starts to let water in, and the water inlet valve closes after a set time; S22: The water level sensor detects the current water level frequency value f; S23: Compare the current water level frequency value f with the calibrated normal frequency lower limit value f1 and normal frequency upper limit value f2. If f1 < f < f2, execute step S28; if f > f2, execute step S24; if f < f1, execute step S25; S24: Determine whether the number of times f>f2 reaches N2 times continuously. If so, the main control board issues a water shortage fault alarm. If not, the drainage pump drains for a set time and returns to step S21; S25: Compare the current water level frequency value f with the calibrated overflow frequency upper limit f4. If f<f4, execute step S27; if f1>f>f4, execute step S26. S26: Determine whether the number of times f1>f>f4 reaches N3 times continuously. If so, the drain pump is turned on and the main control board issues an excessive water inflow alarm. If not, detect whether there is a drainage fault. If there is a drainage fault, the drain pump starts to drain continuously and reports a drainage fault. If there is no drainage fault, return to step S21. S27: The drainage pump continues to drain water, and the main control board issues a water overflow fault alarm; S28: The water inlet procedure ends.

2. The water level detection method according to claim 1, characterized in that: In the drainage procedure, the water level detection method includes: S11: The drainage pump starts to drain water, and the drainage pump is turned off after a set time; S12: The water level sensor detects the current water level frequency value f; S13: Compare the current water level frequency value f with the calibrated empty bucket frequency lower limit f3. If f<f3, execute step S14; if f≥f3, execute step S16. S14: Determine whether the number of times f<f3 reaches N1 times continuously. If so, execute step S15; if not, return to step S11; S15: The drainage pump continues to drain water, and the main control board issues a drainage failure alarm; S16: The drainage process ends.

3. The water level detection method according to claim 2, characterized in that: In the water inlet procedure, the water level detection method further includes: before executing step S21, first detecting whether there is a drainage fault.

4. The water level detection method according to claim 2, characterized in that: In step S11 and step S24, the drainage pump adopts intermittent drainage, and the drainage time is set to 1 minute. The drainage pump cycles 4 times in a manner of opening for 10 seconds and pausing for 5 seconds.

5. The water level detection method according to claim 2, characterized in that: In step S15 and step S27, the drainage pump continuously drains water in a manner that the drainage pump operates in a cycle of being turned on for 30 seconds and turned off for 15 seconds.

6. The water level detection method according to claim 2, characterized in that: The value ranges of N1, N2 and N3 are: N1≥2, N2≥2, N3≥2.

7. The water level detection method according to any one of claims 2 to 6, characterized in that: The water inlet program and the water discharge program include water inlet subprograms and water discharge subprograms involved in the pre-wash stage, the main wash stage, the cold rinse stage and the hot rinse stage.

8. A dishwasher, characterized in that: The water level of the inner tank is detected using the water level detection method described in any one of claims 1 to 7. The dishwasher includes a water level sensor and a water tank. The water level sensor is installed on the outside of the inner tank. The water level sensor can detect the water level pressure in the inner tank and convert the pressure signal into a frequency signal and feed it back to the main control board. A chamber is provided on the water tank, and the water level sensor is connected to the chamber through a pressure conduit.

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