Water level monitoring circuit and sewage elevator

Abstract

The water level monitoring circuit and the sewage elevator provided in the embodiments of the present disclosure comprise: a power supply circuit; a switch unit provided with a control end for controlling the on-off state of the switch unit; the on-off state controls the conduction and disconnection of the power supply circuit to correspondingly control the start and stop of a drainage motor; a liquid level detection unit arranged in a water collecting tank of the sewage elevator, for detecting the water level in the water collecting tank and outputting a water level detection signal corresponding to the water level; and a main control unit, which is configured to generate on / off control of the switch unit according to the water level detection signal to maintain the water level in a preset range. The main control unit receives the water level detection signal output by the liquid level detection unit in real time, and generates an on / off control instruction of the switch unit based on the water level detection signal, so that the start and stop of the drainage motor correspond to the actual water level change in the water collecting tank, and the water level is always maintained in a preset safe range, thereby avoiding overflow caused by control lag or misjudgment.

Description

Technical Field

[0001] This disclosure relates to the field of sewage lifting equipment technology, and in particular to water level monitoring circuits and sewage lifting equipment. Background Technology

[0002] Sewage lifting stations are widely used in building basements, underground commercial spaces, subway stations, and other places where gravity drainage is not possible. They are used to collect and discharge domestic sewage, ensuring that low-lying areas do not experience water accumulation or overflow. A typical sewage lifting station includes a collection tank, a drainage motor, a sewage pump, and a control system. When the liquid accumulates to a certain height, the drainage motor must be started promptly; when the liquid reaches a safe low level, the motor should be reliably stopped to avoid ineffective operation or dry running.

[0003] If the control system cannot accurately determine the true liquid level in the collection tank, it will lead to two typical risks: first, the sewage pump may be delayed or fail to start, causing the water level to rise continuously until it overflows, resulting in property damage or safety accidents; second, the high water level may be misjudged, leading to frequent start-stop of the motor. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this disclosure is to provide a water level monitoring circuit and a sewage lifting device to solve the problems in the related technology.

[0005] The first aspect of this disclosure provides a water level monitoring circuit, which is applied to a sewage lifting station and includes:

[0006] A power supply circuit, wherein the input terminal of the power supply circuit is connected to an external power source, and the output terminal of the power supply circuit is connected to the drainage motor of the sewage lifting station to form a power supply circuit for supplying power to the drainage motor;

[0007] A switching unit, connected in series in the power supply circuit, is provided with a control terminal for controlling its own on / off state; the on / off state controls the conduction and disconnection of the power supply circuit to correspondingly control the start and stop of the drainage motor;

[0008] A liquid level detection unit is installed in the water collection tank of the sewage lifting device to detect the water level in the water collection tank and output a water level detection signal corresponding to the water level.

[0009] The main control unit includes a signal input terminal connected to the liquid level detection unit and a drive output terminal connected to the control terminal; the main control unit is used to generate a control signal for the on / off control of the switch unit based on the water level detection signal to maintain the water level within a preset range.

[0010] In an embodiment of the first aspect, the main control unit is integrated with or connected to a memory that stores an upper limit threshold and a lower limit threshold for comparison with the water level represented by the water level detection signal.

[0011] In an embodiment of the first aspect, the liquid level detection unit includes a water level detection sensor, which is disposed in the water collection tank and is used to detect the water level in the water collection tank to obtain the water level detection signal.

[0012] In a first aspect embodiment, the liquid level detection unit further includes:

[0013] The signal processing unit is connected to the water level detection sensor and the signal input terminal, respectively, and is used to convert the analog signal into a digital signal and output the water level detection signal corresponding to the digital signal to the main control unit.

[0014] In a first aspect embodiment, the signal processing unit includes:

[0015] The processing chip includes a positive signal input terminal and a negative signal input terminal respectively coupled to the water level detection sensor, and a signal output terminal coupled to the signal input terminal;

[0016] The first resistor is coupled between the positive signal input terminal and the water level detection sensor.

[0017] The second resistor is coupled between the negative signal input terminal and the water level detection sensor.

[0018] The first capacitor is coupled to the first resistor and the second resistor respectively.

[0019] In a first aspect embodiment, the switching unit includes:

[0020] A first switching element is connected in series in the power supply circuit, between the power supply circuit and the drainage motor, for controlling the on / off state of the power supply circuit;

[0021] The second switching element is coupled between the first switching element and the drive output terminal, and is used to control the on / off state of the first switching element according to the control signal.

[0022] In an embodiment of the first aspect, the second switching element is implemented as a transistor, the base of which is coupled to the drive output terminal through a third resistor, the collector is coupled to the first switching element, and the emitter is grounded; the transistor controls the conduction state between the collector and the emitter based on the control signal input to the base.

[0023] In the first aspect of the embodiment, the main control unit further includes at least one feedback terminal, used to output a feedback signal that feeds back the water level in the water collection tank based on the water level detection signal; the water level monitoring circuit further includes at least one alarm unit connected to the feedback terminal, used to generate an alarm message based on the feedback signal and send it to the outside.

[0024] In an embodiment of the first aspect, the power supply circuit includes a power conversion unit, the input terminal of which is coupled to an external power supply, and the output terminal is coupled to the main control unit, the switching unit and the liquid level detection unit respectively, for providing operating voltage.

[0025] The second aspect of this disclosure provides a wastewater lifting device, which includes the water level monitoring circuit described in any embodiment of the first aspect above.

[0026] The beneficial effects of this disclosure are: the main control unit receives the water level detection signal output by the liquid level detection unit in real time, and generates on / off control commands for the switch unit based on the water level detection signal, so that the start and stop of the drainage motor corresponds to the actual water level change in the water collection tank, ensuring that the water level is always maintained within the preset safe range, and avoiding overflow caused by control lag or misjudgment. Attached Figure Description

[0027] Figure 1 A schematic diagram of the water level monitoring circuit in one embodiment of this disclosure is shown.

[0028] Figure 2 A circuit diagram of a water level monitoring circuit according to one embodiment of the present disclosure is shown.

[0029] Figure 3 A circuit diagram of a liquid level detection unit in one embodiment of this disclosure is shown. Detailed Implementation

[0030] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the information disclosed herein. This disclosure can also be implemented or applied through other different specific embodiments, and various details in this disclosure can be modified or changed according to different viewpoints and application modules without departing from the spirit of this disclosure. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be combined with each other.

[0031] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings, so that those skilled in the art to which this disclosure pertains can readily implement it. This disclosure may be embodied in many different forms and is not limited to the embodiments described herein.

[0032] In this disclosure, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic represented in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. Furthermore, the specific features, structures, materials, or characteristics represented may be combined in any suitable manner in any one or a group of embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples represented in this disclosure, as well as the features of those different embodiments or examples.

[0033] Furthermore, the terms "first" and "second" are used for illustrative purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the representation of this disclosure, "a set" means two or more, unless otherwise explicitly specified.

[0034] For the purpose of clarity, devices unrelated to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0035] Throughout this specification, when it is said that a device is "connected" to another device, this includes not only "direct connection" but also "indirect connection" by placing other components in between. Furthermore, when it is said that a device "comprises" a certain constituent element, unless otherwise stated otherwise, this does not exclude other constituent elements, but rather implies that other constituent elements may be included.

[0036] While the terms first, second, etc., are used in some examples herein to refer to various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, first interface and second interface, etc., are used. Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of features, steps, operations, elements, modules, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, modules, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are interpreted as inclusive, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition will only occur if the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0037] The technical terms used herein are for reference only to specific embodiments and are not intended to limit the scope of this disclosure. The singular form used herein includes the plural form unless the statement explicitly indicates otherwise. The word "comprising" as used in this specification means to specify a particular characteristic, region, integer, step, operation, element, and / or component, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0038] Although not explicitly defined, all terms, including technical and scientific terms used herein, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms defined in commonly used dictionaries shall be further interpreted as having a meaning consistent with the relevant technical literature and the message of the present disclosure, and shall not be over-interpreted as having an ideal or overly formulaic meaning unless otherwise defined.

[0039] A sewage lifting station typically includes a collection tank (also called a sewage tank) for temporarily storing domestic sewage and a sewage pump driven by a drainage motor. The collection tank is located in low-lying areas such as basements and bathrooms to collect sewage that cannot drain by gravity. When the drainage motor starts, it drives the sewage pump to pressurize and transport the sewage in the collection tank to the outside. Therefore, the timing of the drainage motor's start and stop directly affects whether sewage can be discharged in a timely manner and whether the collection tank overflows; its control logic is also related to the actual water level in the collection tank.

[0040] In order to control the water level in the water collection tank, one embodiment of this disclosure provides a water level monitoring circuit.

[0041] Figure 1 The embodiment is a schematic diagram of the water level monitoring circuit of this disclosure.

[0042] exist Figure 1 In this embodiment, the water level monitoring circuit includes: a power supply circuit 200, a switching unit 300, a liquid level detection unit 400, and a main control unit 500.

[0043] The input terminal of the power supply circuit 200 is connected to an external power supply 210, and the output terminal is connected to the drainage motor 110 of the sewage lifting station to form a power supply circuit for supplying power to the drainage motor 110.

[0044] Specifically, as an example, in Figure 1 In this circuit, the input terminal of the power supply circuit 200 is connected to an external power source 210 (such as mains power), and its output terminal is connected to the drainage motor 110 of the sewage lifting station, forming a power supply circuit to supply power to the drainage motor 110 to support its normal operation.

[0045] Optionally, in Figure 1In the example, the power supply circuit 200 includes a power conversion unit 220. The input terminal of the power conversion unit 220 is coupled to an external power supply 210 (such as AC mains power), and its output terminal is coupled to the main control unit 500, the switching unit 300 and the liquid level detection unit 400, respectively, to convert the external power supply 210 into a suitable DC working voltage to meet the power supply requirements of each functional module.

[0046] Figure 2 The embodiment is a circuit diagram of the water level monitoring circuit.

[0047] Optionally, in Figure 2 In this embodiment, the power supply circuit 200 further includes a first filter capacitor C1 and a second filter capacitor C2, which are connected in parallel between the output terminal and the ground terminal of the power conversion unit 220. They are used to filter and store energy in the regulated DC voltage, effectively suppressing power ripple and transient interference.

[0048] In another embodiment, the power conversion unit 220 is further provided with a first fuse P1 in the front stage, which is connected in series between the external power supply 210 and the power conversion unit 220. It is used to melt in time when abnormal conditions such as short circuit, overcurrent or surge occur at the input terminal, cut off the power supply to the subsequent circuit, play the role of primary overcurrent protection, prevent the fault from expanding and ensure the safety of equipment and personnel.

[0049] Furthermore, the power conversion unit 220 is further equipped with an external trigger switch 230, which can be manually operated by the user or driven by an external control system. For example, during equipment maintenance, testing, or long-term shutdown, the main control unit 500 and subsequent circuits can be de-energized by disconnecting the external trigger switch 230, achieving physical-level power isolation, which improves safety and reduces standby power consumption.

[0050] exist Figure 1 In this embodiment, the switch unit 300 is connected in series in the power supply circuit and is provided with a control terminal for controlling its own on / off state; the on / off state is used to control the conduction and disconnection of the power supply circuit, thereby correspondingly controlling the start and stop of the drainage motor 110.

[0051] Optionally, in Figure 2 In this embodiment, the switching unit 300 includes a first switching element 310 and a second switching element K1. The first switching element 310 is connected in series in the power supply circuit, between the power supply circuit 200 and the drainage motor 110. The second switching element K1 is coupled between the first switching element 310 and the drive output terminal 503 of the main control unit 500, and is used to drive the first switching element 310 to operate according to the control signal output by the main control unit 500.

[0052] Optionally, the first switching element 310 is implemented as a relay. The coil of the relay is driven by the second switching element K1, and its contacts are connected in series in the AC power supply main circuit. It has the advantages of strong electrical isolation capability and good voltage and current resistance, and is suitable for the control scenario of drainage motor 110 with frequent start and stop and large load in sewage lifting station.

[0053] Optionally, the second switching element K1 is implemented as a transistor.

[0054] Specifically, the base of the second switching element K1 is coupled to the drive output terminal 503 of the main control unit 500 through the third resistor R3 to receive control signals; the collector is coupled to one end of the coil of the relay (i.e., the first switching element 310), and the emitter is grounded. When the main control unit 500 outputs a high-level control signal, the transistor is turned on, the relay coil is energized, its contacts are closed, the power supply circuit is connected, and the drainage motor 110 starts; when the control signal is low-level, the transistor is turned off, the relay is de-energized and released, the contacts are opened, and the motor stops running.

[0055] Furthermore, in Figure 2 In this embodiment, a first diode D1 is connected in parallel across the coil of the relay, with its anode connected to the ground terminal of the coil and its cathode connected to the power supply terminal of the coil. When the second switching element K1 is suddenly turned off from the on state, the relay coil will generate a reverse high-voltage electromotive force due to its inductive characteristics, which may damage the driving device or cause electromagnetic interference. By connecting the first diode D1 in parallel, control components such as transistors can be protected from voltage spike damage, while also suppressing switching transient noise.

[0056] Optionally, the liquid level detection unit 400 is installed inside the water collection tank 100 of the sewage lifting station, used to detect the water level in the water collection tank 100 and output a water level detection signal corresponding to the water level. The liquid level detection unit 400 can employ contact or non-contact sensor technology to monitor the water level changes in the water collection tank 100 in real time and output a water level detection signal corresponding to the water level. The water level detection signal reflects the current water level height or trend of change.

[0057] Figure 3 The embodiment is a circuit diagram of the liquid level detection unit 400.

[0058] like Figure 3As shown, the liquid level detection unit 400 includes a water level detection sensor 410 and a signal processing unit 420 electrically connected. The water level detection sensor 410 can be installed inside the collection tank 100 of the sewage lifting station to sense changes in the water level in the tank in real time; the other circuit modules (such as the signal processing unit 420, power supply circuit 200, switching unit 300, and main control unit 500, etc.) can be arranged outside the collection tank 100 to avoid long-term immersion or humid environment affecting the electronic components. It should be noted that the specific installation position and implementation method of the above circuits do not constitute a limitation of this application and can be flexibly adjusted according to the actual product structure and protection requirements.

[0059] Specifically, the water level detection sensor 410 is used to detect the water level in the water collection tank 100 and output a corresponding water level detection signal. When the water level detection sensor 410 itself has digital output capability (such as integrated ADC or communication interface), its output signal can be directly sent to the main control unit 500 as a water level detection signal without additional processing.

[0060] Furthermore, when the water level detection sensor 410 outputs an analog signal (e.g., a voltage or current signal whose amplitude changes continuously with the water level), to facilitate accurate identification and processing by the main control unit 500, the signal processing unit 420 can be connected to the water level detection sensor 410 and... Figure 2 The main control unit 500 is located between signal input terminals 502 and includes an analog-to-digital converter (ADC) for converting the analog signal into a digital signal and outputting the digital signal as a water level detection signal to the main control unit 500.

[0061] Specifically, in Figure 3 In this embodiment, the signal processing unit 420 includes a processing chip 421, which has a positive signal input terminal 4211, a negative signal input terminal 4212, and a signal output terminal 4213. The positive signal input terminal 4211 is coupled to the water level detection sensor 410 through a first resistor R1, and the negative signal input terminal 4212 is coupled to the water level detection sensor 410 through a second resistor R2. The signal output terminal 4213 is connected to the signal input terminal 502 of the main control unit 500 and outputs a digital signal after comparison or analog-to-digital conversion.

[0062] also, Figure 3 In this embodiment, a first capacitor C3 is connected in parallel between the first resistor R1 and the second resistor R2 to filter out high-frequency noise and stabilize the input signal.

[0063] Optionally, in Figure 3In this embodiment, the signal processing unit 420 and the water level detection sensor 410 are electrically connected through a first port 411 and a second port 422. The first port 411 is located on the side of the water level detection sensor 410 and is used to output the raw analog signal it senses. The second port 422 is located on the side of the signal processing unit 420 and is used to receive the analog signal and perform subsequent processing. The first port 411 and the second port 422 are coupled together via port plugs, wires, or flexible circuits, forming an analog signal transmission channel from the sensor to the signal processing unit 420.

[0064] Optionally, Figure 3 In this embodiment, the signal processing unit 420 further includes a first power supply terminal 4214, which is coupled to the output terminal of the power conversion unit 220 and is used to provide operating power to the processing chip 421. A second capacitor C4 is also coupled between the first power supply terminal 4214 and ground to filter the power supply voltage, suppress power supply noise, and ensure stable operation of the signal processing unit 420.

[0065] Optionally, the signal processing unit 420 further includes a first ground terminal 4215 and a reference voltage terminal 4216, wherein the reference voltage terminal 4216 is used to provide the reference voltage required by the analog-to-digital converter or comparator. A third capacitor C5 and a fourth capacitor C6 are connected in parallel between the reference voltage terminal 4216 and the first ground terminal 4215, which together form a filter network to stabilize the reference voltage and filter out high-frequency interference.

[0066] Combination Figure 2 The main control unit 500 includes a chip power supply terminal 501 coupled to the output terminal of the power conversion unit 210, a signal input terminal 502 connected to the liquid level detection unit 400, and a drive output terminal 503 connected to the control terminal; the main control unit 500 is used to generate a control signal for the on / off control of the switching unit 300 based on the water level detection signal to maintain the water level within a preset range.

[0067] exist Figure 2 In this embodiment, the main control unit 500 includes a signal input terminal 502 connected to the liquid level detection unit 400 and a drive output terminal 503 connected to the control terminal of the switching unit 300. Based on the received water level detection signal, the main control unit 500 intelligently generates an on / off control signal for the switching unit 300 to maintain the water level in the collection tank 100 within a preset safe range. For example, when the water level rises to a set pump start threshold, the main control unit 500 issues a start command, causing the switching unit 300 to close and the drainage motor 110 to start operating; when the water level drops to a set pump stop threshold, the main control unit 500 issues a stop command, cutting off the power supply circuit and stopping the motor.

[0068] Optionally, the main control unit 500 integrates or is connected to a memory that stores an upper limit threshold and a lower limit threshold for comparison with the water level represented by the water level detection signal.

[0069] Specifically, in Figure 1 In this embodiment, the upper limit threshold of the water level in the memory corresponds to the high water level line H of the water collection tank 100. When the water level detected by the liquid level detection unit 400 reaches or exceeds this threshold, it indicates that the water level in the water collection tank 100 is too high and there is a risk of overflow. At this time, the main control unit 500 determines that the drainage motor 110 needs to be started based on the stored upper limit threshold of the water level, and connects the power supply circuit through the control switch unit 300 to start the drainage motor 110 to start working and discharge sewage in a timely manner.

[0070] Correspondingly, the lower water level threshold corresponds to the low water level line L of the water collection tank 100. When the water level detected by the level detection unit 400 drops below this threshold, it indicates that the water in the water collection tank 100 has been drained and there is no need to continue running the drainage motor 110. At this time, the main control unit 500 issues a command based on the stored lower water level threshold to control the switch unit 300 to disconnect the power supply circuit, causing the drainage motor 110 to stop working and avoid unnecessary operation.

[0071] In addition, Figure 2 In the main control unit 500, there is also a first interface connection terminal 504 coupled to the third port 501 for external communication or extended functions. A fifth capacitor is also connected in parallel between the connection terminal of the third port 501 and ground for filtering out high-frequency interference.

[0072] The main control unit 500 also includes a second interface connection terminal 505, which is connected to the output terminal of the power conversion unit 220 through the fourth port 240, and is used to provide a stable working power supply for the internal circuit of the main control unit 500.

[0073] Optionally, the main control unit 500 further includes at least one feedback terminal for outputting a feedback signal characterizing the water level status in the collection tank 100 based on the water level detection signal. The water level monitoring circuit further includes at least one alarm unit 600 connected to the feedback terminal for generating alarm information based on the feedback signal and sending it to the outside.

[0074] As an example, the alarm unit 600 may include a sound alarm unit 610 and a light alarm unit. Figure 2In this embodiment, the feedback terminal includes an alarm signal terminal 506 coupled to the sound alarm unit 610 and at least one display feedback terminal 507 coupled to the light alarm unit 620. The sound alarm unit 610 includes a speaker 611 and a third switching element K2. The third switching element K2 has a fourth terminal, a fifth terminal, and a sixth terminal for controlling its on / off state: the fourth terminal is coupled to the output terminal of the power conversion unit 220 via a fourth resistor R4, the fifth terminal is grounded, and the sixth terminal is coupled to the alarm signal terminal 506 via a fifth resistor R5. When the main control unit 500 outputs a valid level through the alarm signal terminal 506, the third switching element K2 is turned on, driving the speaker 611 to emit sound, thus achieving an audible and visual alarm.

[0075] at the same time, Figure 2 The embodiment is provided with four display feedback terminals 507, which are coupled to the first light-emitting diode D1, the second light-emitting diode D2, the third light-emitting diode D3, and the fourth light-emitting diode D4 through the first feedback resistor R6, the second feedback resistor R7, the third feedback resistor R8, and the fourth feedback resistor R9, respectively, to intuitively indicate the current water level range or system status with different lighting combinations.

[0076] Optionally, the first LED D1 is used to indicate a low water level or standby state, the second LED D2 is used to indicate that the drainage motor 110 is operating normally, the third LED D3 is used to indicate an overload warning, and the fourth LED D4 is used to indicate a system fault.

[0077] In another embodiment of this disclosure, a sewage lifting station is provided, including the water level monitoring circuit described in any of the above embodiments. By integrating the water level monitoring circuit, the sewage lifting station can obtain real-time water level changes in the collection tank 100 and intelligently control the start and stop of the drainage motor 110 based on a preset threshold, effectively preventing overflow.

[0078] The above embodiments are merely illustrative of the principles and effects of this disclosure and are not intended to limit this disclosure. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this disclosure. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this disclosure should still be covered by the protection scope of this disclosure.

Claims

1. A water level monitoring circuit, characterized in that, Applications in wastewater lifting stations include: A power supply circuit, wherein the input terminal of the power supply circuit is connected to an external power source, and the output terminal of the power supply circuit is connected to the drainage motor of the sewage lifting station to form a power supply circuit for supplying power to the drainage motor; A switching unit, connected in series in the power supply circuit, is provided with a control terminal for controlling its own on / off state; the on / off state controls the conduction and disconnection of the power supply circuit to correspondingly control the start and stop of the drainage motor; A liquid level detection unit is installed in the water collection tank of the sewage lifting device to detect the water level in the water collection tank and output a water level detection signal corresponding to the water level. The main control unit includes a signal input terminal connected to the liquid level detection unit and a drive output terminal connected to the control terminal; the main control unit is used to generate a control signal for the on / off control of the switch unit based on the water level detection signal to maintain the water level within a preset range.

2. The water level monitoring circuit according to claim 1, characterized in that, The main control unit is integrated with or connected to a memory that stores upper and lower water level thresholds for comparison with the water level represented by the water level detection signal.

3. The water level monitoring circuit according to claim 1, characterized in that, The liquid level detection unit includes a water level detection sensor, which is located inside the water collection tank and is used to detect the water level in the water collection tank to obtain the water level detection signal.

4. The water level monitoring circuit according to claim 3, characterized in that, The liquid level detection unit further includes: The signal processing unit is connected to the water level detection sensor and the signal input terminal, respectively, and is used to convert the analog signal into a digital signal and output the water level detection signal corresponding to the digital signal to the main control unit.

5. The water level monitoring circuit according to claim 4, characterized in that, The signal processing unit includes: The processing chip includes a positive signal input terminal and a negative signal input terminal respectively coupled to the water level detection sensor, and a signal output terminal coupled to the signal input terminal; The first resistor is coupled between the positive signal input terminal and the water level detection sensor. The second resistor is coupled between the negative signal input terminal and the water level detection sensor. The first capacitor is coupled to the first resistor and the second resistor respectively.

6. The water level monitoring circuit according to claim 1, characterized in that, The switching unit includes: A first switching element is connected in series in the power supply circuit, between the power supply circuit and the drainage motor, for controlling the on / off state of the power supply circuit; The second switching element is coupled between the first switching element and the drive output terminal, and is used to control the on / off state of the first switching element according to the control signal.

7. The water level monitoring circuit according to claim 6, characterized in that, The second switching element is implemented as a transistor, the base of which is coupled to the drive output terminal through a third resistor, the collector is coupled to the first switching element, and the emitter is grounded; the transistor controls the conduction state between the collector and the emitter based on the control signal input to the base.

8. The water level monitoring circuit according to claim 1, characterized in that, The main control unit further includes at least one feedback terminal, used to output a feedback signal that reflects the water level in the water collection tank based on the water level detection signal; the water level monitoring circuit further includes at least one alarm unit connected to the feedback terminal, used to generate an alarm message based on the feedback signal and send it to the outside.

9. The water level monitoring circuit according to claim 1, characterized in that, The power supply circuit includes a power conversion unit. The input terminal of the power conversion unit is coupled to an external power source, and the output terminal is coupled to the main control unit, the switching unit, and the liquid level detection unit, respectively, to provide operating voltage.

10. A sewage lifting station, characterized in that, Includes the water level monitoring circuit according to any one of claims 1-9.

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