Patent Publication Number: US-2023148824-A1

Title: Water tank assembly, pumping and drainage system, reversing valve, base station body, base station, and cleaning system

Description:
RELATED APPLICATIONS 
     This application is a divisional application of the parent application with application Ser. No. 18/070,477 filed on Nov. 29, 2022. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to technical field of cleaning apparatus. 
     BACKGROUND 
     Recently, more and more cleaning apparatus have entered people&#39;s lives. In order to facilitate the use of the cleaning apparatus, base station has been provided to service the cleaning apparatus, and has increasingly become an inseparable supporting device for the cleaning apparatus. The base station generally includes a clean water tank having a clean water cavity for outputting clean water, and a sewage tank having a sewage cavity for receiving sewage. In order to be more convenient for users, the inventors have invented a base station that can automatically feed clean water to the clean water tank by connecting a water inlet pipe of the clean water tank to an external pipeline during the base station is in use. 
     However, the cleaning apparatus mentioned above has the defects: water in the water inlet channel of the clean water tank is prone to leak from the water inlet channel at the time the external pipeline is removed. 
     SUMMARY 
     An object of the present disclosure is to provide a water tank assembly which can block water in the water inlet channel from flowing back. 
     A first aspect of the embodiments of the present disclosure provides a water tank assembly which is configured to be installed on a base station, and the water tank assembly comprises: 
     a tank body defined with a clean water cavity, the clean water cavity is communicated with an external pipeline through a water inlet channel, the external pipeline is capable of transporting clean water into the clean water cavity; and 
     a one-way valve arranged in the water inlet channel, the one-way valve has a first state and a second state, when the one-way valve is in the first state, water in the external pipeline is allowed to flow to the clean water cavity; when the one-way valve is in the second state, water in the clean water cavity is restricted to flow out along the water inlet channel. 
     The water tank assembly of the present disclosure, during delivering clean water to the clean water cavity, the one-way valve is in the first state to allow water in the external pipeline to be delivered to the clean water cavity, and when delivery of clean water to the clean water cavity is stopped, the one-way valve can be changed to the second state to restrict the water in the clean water cavity flowing out along the water inlet channel, such that outflow of the clean water from the clean water cavity can be blocked when the external pipeline is removed. 
     A second aspect of the embodiments of the present disclosure provides a base station for servicing a cleaning apparatus. The base station comprises a base station body and the water tank assembly as described above, the base station body is provided with a cleaning system, and the clean water cavity is configured to supply clean water to the cleaning system. 
     A third aspect of the embodiments of the present disclosure provides a water tank assembly which is configured to be installed on a base station, and the water tank assembly comprises: 
     a tank body defined with a sewage cavity, the tank body is provided with a water inlet channel and a sewage discharging channel both communicating with the sewage cavity; 
     the sewage cavity is configured to receive the sewage coming through the water inlet channel under a negative pressure inside the sewage cavity introduced by an external air source, and is configured to discharge the sewage through the sewage discharging channel under a positive pressure inside the sewage cavity introduced by the external air source; and 
     a one-way valve arranged in the water inlet channel, when the sewage cavity is in a positive pressure state, the one-way valve is in a closed state, and when the sewage cavity is in a negative pressure state, the one-way valve is in an open state. 
     As the water tank assembly of the present disclosure being used, when external air source applies negative pressure to the sewage cavity, the one-way valve is in an open state, so that sewage can be sucked into the sewage cavity through the water inlet channel. When sewage in the sewage cavity needs to be discharged, the external air source applies positive pressure to the sewage cavity, so that the sewage can be discharged through the sewage discharging channel; and the one-way valve is closed, which can block outflow of the gas in the sewage cavity from the one-way valve in the water inlet channel, so that sewage in the sewage cavity is capable of being discharged from the sewage discharging channel under the positive pressure. In addition, the arrangement of the one-way valve can also block the sewage flowing back from the water inlet channel under the positive pressure. 
     A fourth aspect of the embodiments of the present disclosure provides abase station which is configured for servicing a cleaning apparatus. The base station comprises a base station body and the water tank assembly as described above, the base station body is provided with a cleaning system, and the sewage cavity is configured to receive sewage produced by the cleaning system. 
     A fifth aspect of the embodiments of the present disclosure provides a base station body which is configured to be installed with a first water tank or a second water tank. A reversing valve is arranged in the first water tank, an gas pump is mounted in the base station body, wherein the base station body comprises: 
     a negative pressure interface, configured to communicate with an air inlet of the gas pump; 
     a positive pressure interface, configured to dock with the first water tank, the positive pressure interface is provided with a gas inlet that communicates with an air outlet of the gas pump and a docking port for docking with the first water tank, and the gas inlet communicates with the docking port; 
     when the first water tank is installed on the base station body, the negative pressure interface is communicated with the first water tank, and the docking port of the positive pressure interface is in an open state to connect and communicate with the first water tank; 
     when the second water tank is installed on the base station body, the negative pressure interface is communicated with the second water tank, and the positive pressure interface is communicated to the atmosphere. 
     In some embodiments, when the second water tank is installed on the base station body, the docking port of the positive pressure interface is in a closed state. 
     In some embodiments, the positive pressure interface is defined with an exhaust port communicated with the gas inlet; when the first water tank is installed on the base station body, the exhaust port is in a closed state, and gas from the gas pump enters the first water tank through the gas inlet, the docking port, and the reversing valve; when the second water tank is installed on the base station body, gas from the gas pump is discharged to the atmosphere through the gas inlet and the exhaust port. 
     In some embodiments, the positive pressure interface further comprises a concave portion defined on the base station body, and the concave portion defines a communicating cavity; the communicating cavity is configured to communicate with the gas inlet, the docking port, and the exhaust port respectively; in case the second water tank is installed on the base station body, gas from the gas pump first enters the communicating cavity from the gas inlet, and then is discharged into the atmosphere through the exhaust port. 
     In some embodiments, the maximum cross-sectional area of a gas channel of the gas inlet is smaller than the maximum cross-sectional area of a gas channel of the communicating cavity, and the maximum cross-sectional area of the gas channel of the communicating cavity is larger than the maximum cross-sectional area of a gas channel of the exhaust port. 
     In some embodiments, the docking port is a concave docking port, the first water tank comprises a protruding gas inlet connector, and the gas inlet connector is capable of being inserted into the concave docking port to communicate with the concave docking port; or 
     the docking port is a convex docking port, the convex docking port is located in the concave portion, and protrudes upwards from a bottom of the concave portion, the first water tank comprises a convex gas inlet connector, and the convex docking port is capable of being inserted into the gas inlet connector to communicate with the gas inlet connector. 
     In some embodiments, the base station body is further provided with a sealing member, and the sealing member is positioned between the docking port and the gas inlet connector. 
     In some embodiments, in case the docking port is a concave docking port, the sealing member is sleeved on an outer peripheral wall of the gas inlet connector, and abuts an inner side wall of the concave docking port; in case the docking port is a convex docking port, the sealing member is arranged on an inner peripheral wall of the gas inlet connector, and abuts an outer side wall of the convex docking port. 
     In some embodiments, in case the docking port is a concave docking port, the sealing member is provided with annular protrusions protruded on an outer peripheral wall of the sealing member, and the annular protrusions resist against the inner side wall of the concave docking port; in case the docking port is a convex docking port, the sealing member is provided with annular protrusions protruded on an inner peripheral wall of the sealing member, and the annular protrusions resist against the outer side wall of the convex docking port. 
     In some embodiments, the docking port is a concave docking port, the sealing member is defined with an extending portion; the extending portion is located at an end of the sealing member facing the concave docking port, a deformation cavity is defined between the extending portion and the inner side wall of the concave docking port, and the extending portion deforms towards the deformation cavity when there is gas passing through. 
     In some embodiments, the base station body further comprises a covering member, the covering member is movably or detachably connected to the docking port to close or open the docking port. 
     In some embodiments, the covering member is configured to be installed at an opening of the concave portion, to block outflow of gas from the docking port and allow gas from the gas inlet to pass through the communicating cavity and then to be discharged from the exhaust port. 
     In some embodiments, the covering member comprises a rigid member and/or an elastic plug. 
     A sixth aspect of the embodiments of the present disclosure provides a base station which comprises a first water tank or a second water tank, and the base station body as described above; the base station body is configured to be installed with the first water tank or the second water tank. 
     A seventh aspect of the embodiments of the present disclosure provides a cleaning system which comprises the base station as described above and a cleaning apparatus. The base station is configured for servicing the cleaning apparatus. 
     The base station body, the base station, and the cleaning system of the present disclosure are compatible with two kinds of water tanks for gas injection and gas extraction. 
     An eighth aspect of the embodiments of the present disclosure provides a pumping and drainage system which comprises: 
     a first water tank, the first water tank is defined with a water storage cavity and a vent communicated with the water storage cavity; 
     an gas source system communicated with the vent; 
     incase the gas source system is in a first state, air in the water storage cavity is discharged through the vent and the gas source system successively, causing the water storage cavity to be in a negative pressure state, allowing fluid to be inhaled to the water storage cavity; in case the gas source system is in a second state, air is delivered to the water storage cavity by the gas source system through the vent, causing the water storage cavity to be in a positive pressure state, allowing the fluid in the water storage cavity to be discharged. 
     The pumping and drainage system of the present disclosure, gas in the water storage cavity is outputted through the vent of the first water tank by the gas source system, or gas is inputted into the water storage cavity through the vent of the first water tank by the gas source system. Specifically, when the gas source system is in the first state, gas in the water storage cavity is discharged through the vent and the gas source system successively, causing the water storage cavity to be in a negative pressure state, thus water can be sucked into the water storage cavity of the first water tank; when the air source system is in the second state, gas is transported into the water storage cavity through the vent by the gas source system, causing the water storage cavity to be in a positive pressure state, thus water in the water storage cavity of the first water tank can be discharged. The base station provided with the pumping and drainage system can realize automatic collection of fluid to the water tank and automatic discharge of the fluid through the gas source system without manpower participation, which is easy to use, high intelligence, and is capable of improving the user experience. In addition, since it can be realized through the gas source system, the whole structure is relatively simple, and the fluid does not pass through a power device, which reduces the risk of damaging the power device and improves the service life of the device. 
     A ninth aspect of the embodiments of the present disclosure provides a base station which comprises a base station body and the pumping and drainage system as described above. Wherein, the first water tank is installed on the base station body. 
     A tenth aspect of the embodiments of the present disclosure provides a cleaning system which comprises the base station as described above and a cleaning apparatus. 
     An eleventh aspect of the embodiments of the present disclosure provides a reversing valve which comprises: 
     ahousing, a surface of the hosing is defined with at least four gas holes; 
     a reversing member movably arranged in the housing, the reversing member is defined with at least two independent channels, and each channel communicates with two of the gas holes; and 
     a driving member arranged on the housing and in driving connection with the reversing member, the driving member drives the reversing member to move to switch the communication between the channels and different gas holes. 
     The reversing valve of the present disclosure, the reversing member is driven by the driving member to move, so that the channels on the reversing member can be switched to communicate with different gas holes on the surface of the housing, realizing the switching of the gas circuits. When the reversing valve is applied to a base station of a cleaning system, the positive pressure gas inlet pipe, the vent pipe, the negative pressure gas outlet pipe, and the exhaust pipe, which consist the gas pipeline for the water tank, all has one end connected to a different one of the four different gas holes of the reversing valve, and the other end of the positive pressure air inlet pipe is configured for gas inputting, the other end of the vent pipe is connected to the water tank, the other end of the negative pressure suction pipe is configured for gas outputting, and the other end of the exhaust pipe is communicated to the atmospheric environment. The gas circuits are switchable by the reversing valve, when the negative pressure suction pipe is communicated with the vent pipe and the positive pressure air inlet pipe is communicated with the exhaust pipe, a negative pressure is formed inside the water tank, so that water is capable of being inputted to the water tank; when the positive pressure air inlet pipe is communicated with the vent pipe and the negative pressure suction pipe is communicated with the exhaust pipe, a positive pressure is formed inside the water tank, so that water can be discharged from the water tank. A single valve can solve the problems solved by the existing two two-position three-way solenoid valves, which reduces the number of the valve and the cost. Further, the reversing valve only needs to connect the positive pressure air inlet pipe, the vent pipe, the negative pressure suction pipe and the exhaust pipe, so that the number of pipes of the pipeline is reduced, the arrangement of the pipeline becomes simple and misfitting will be reduced, and the cost is further reduced. 
     A twelfth aspect of the embodiments of the present disclosure provides a base station, wherein the base station comprises a base station body and the reversing valve as described above, the base station body is provided with a water tank and a pump body, and the water tank has a vent port and a water guiding port; 
     the reversing member comprises a first channel and a second channel, and the housing has a first gas hole communicated with an output end of the pump body, a second gas hole communicated with an input end of the pump body, a third gas hole communicated with the vent port, and a fourth gas hole communicated to the atmospheric environment; 
     in case the first channel, the first gas hole, and the fourth gas hole are communicated, and the second channel, the second gas hole, and the third gas hole are communicated, a negative pressure is formed inside the water tank, allowing water to be stored in the water tank through the water guiding port; 
     in case the first channel, the first gas hole, and the third gas hole are communicated, and the second channel, the second gas hole, and the fourth gas hole are communicated, a positive pressure is formed inside the water tank, allowing water to be discharged from the water tank through the water guiding port. 
     A thirteenth aspect of the embodiments of the present disclosure provides a cleaning system which comprises the base station as described above and a cleaning apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective diagram of a base station according to an exemplary embodiment of the present disclosure; 
         FIG.  2    is a perspective diagram of the base station from another angle according to an exemplary embodiment of the present disclosure; 
         FIG.  3    is a perspective diagram of a base station bracket and a water tank assembly according to an exemplary embodiment of the present disclosure; 
         FIG.  4    is a perspective diagram of a water tank assembly according to an exemplary embodiment of the present disclosure; 
         FIG.  5    is a cross-sectional view of a water tank assembly according to an exemplary embodiment of the present disclosure; 
         FIG.  6    is an enlarged view of portion A in  FIG.  5   ; 
         FIG.  7    is an enlarged view of portion B in  FIG.  5   ; 
         FIG.  8    is another cross-sectional view of the water tank assembly according to an exemplary embodiment of the present disclosure; 
         FIG.  9    is an enlarged view of portion C in  FIG.  8   ; 
         FIG.  10    is a schematic diagram of an adapter of the water tank assembly connecting with external pipeline according to an exemplary embodiment of the present disclosure; 
         FIG.  11   a    is a schematic diagram of a first water tank according to an exemplary embodiment of the present disclosure; 
         FIG.  11   b    is a cross-sectional view of a first water tank according to an exemplary embodiment of the present disclosure; 
         FIG.  11   c    is a first cross-sectional view of a second tank body according to an exemplary embodiment of the present disclosure; 
         FIG.  11   d    is a second cross-sectional view of a second tank body according to an exemplary embodiment of the present disclosure; 
         FIG.  11   e    is an enlarged view of portion A in  FIG.  11     d;    
         FIG.  12    is a schematic diagram of a base station body according to an exemplary embodiment of the present disclosure; 
         FIG.  13   a    is a schematic diagram of the base station body in  FIG.  12    from another angle; 
         FIG.  13   b    is a schematic view of a base station with a rear housing being removed according to an exemplary embodiment of the present disclosure; 
         FIG.  14   a    is a gas circuit schematic diagram in the case the first water tank is installed on the base station body according to an exemplary embodiment of the present disclosure; 
         FIG.  14   b    is a gas circuit schematic diagram in the case a second water tank is installed on the base station body according to an exemplary embodiment of the present disclosure; 
         FIG.  15   a    is a cross-sectional view of the base station body in  FIG.  12   ; 
         FIG.  15   b    is an enlarged view of portion A in  FIG.  15     a;    
         FIG.  15   c    is a schematic diagram of an air inlet connector of the first water tank connecting with a positive pressure interface according to an exemplary embodiment of the present disclosure; 
         FIG.  15   d    is a cross-sectional view of the base station body according to another exemplary embodiment of the present disclosure; 
         FIG.  15   e    is an enlarged view of portion A′ in  FIG.  15     d;    
         FIG.  16   a    is a cross-sectional view of the base station body according to a further exemplary embodiment of the present disclosure; 
         FIG.  16   b    is an enlarged view of portion B in  FIG.  16     a;    
         FIG.  16   c    is a cross-sectional view of the base station body with the air inlet connector of the first water tank connecting with the positive pressure interface according to another exemplary embodiment of the present disclosure; 
         FIG.  16   d    is a schematic diagram of a part of structure in  FIG.  16     c;    
         FIG.  16   e    is a schematic diagram of a base station body according to a further exemplary embodiment of the present disclosure; 
         FIG.  16   f    is an enlarged view of portion B′ in  FIG.  16     e;    
         FIG.  16   g    is a schematic diagram of the second water tank being installed on the base station body according to an exemplary embodiment of the present disclosure; 
         FIG.  16   h    is a schematic diagram of the second water tank according to an exemplary embodiment of the present disclosure; 
         FIG.  17    is a schematic diagram of a reversing valve according to an exemplary embodiment of the present disclosure; 
         FIG.  18    is a first exploded view of the reversing valve in  FIG.  17   ; 
         FIG.  19    is a cross-sectional view of the reversing valve in  FIG.  17   ; 
         FIG.  20    is a second exploded view of the reversing valve in  FIG.  17   ; 
         FIG.  21    is an exploded view of a reversing valve according to an exemplary embodiment of the present disclosure; 
         FIG.  22    is a schematic view of an inner structure of the reversing valve according to an exemplary embodiment of the present disclosure; 
         FIG.  23    is a schematic diagram of the reversing valve under one view according to an exemplary embodiment of the present disclosure; 
         FIG.  24    is a schematic diagram of the reversing valve under another view according to an exemplary embodiment of the present disclosure; 
         FIG.  25    is a water suck schematic diagram of the water tank applied with the reversing valve according to an exemplary embodiment of the present disclosure; and 
         FIG.  26    is a drainage schematic diagram of the water tank applied with the reversing valve according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In order to explain the technical content, construction features, the purpose and effect achieved by the present disclosure, the following is described in detail combined with the embodiments and the attached drawings. 
     As shown in  FIG.  1    to  FIG.  10   , the present disclosure provides a base station configured for servicing cleaning apparatus, such as, for cleaning the cleaning apparatus, replenishing water for the cleaning apparatus which is equipped with a clean water tank, and/or, discharging sewage of the cleaning apparatus which is equipped with a sewage tank. The cleaning apparatus may include a cleaning robot that can move automatically, or a handheld cleaning apparatus that can be hand-held and driven by users, such as a hand-held cleaning device, etc. 
     The base station may include a base station body  210  and a water tank assembly  102 . In some embodiments, a cleaning system X may be provided on the base station body  210 . The cleaning system X is configured to transport clean water required by the base station for cleaning mopping members of the cleaning robot. In some embodiments, the cleaning system may be configured to suck sewage produced during the base station cleaning the mopping members of the cleaning robot. 
     In some embodiments, as shown in  FIG.  3   , the water tank assembly  102  may be installed on a base station bracket  101  of the base station body  210 . 
     The water tank assembly  102  includes a tank body  104  in which a clean water cavity  106  is defined. In some embodiments, the cleaning system X may communicate with the clean water cavity  106 , such that clean water in the clean water cavity  106  can be provided to the cleaning system X. In some other embodiments, when the cleaning apparatus equipped with the clean water tank is docked to the base station, the clean water cavity  106  of the base station can communicate with the clean water tank of the cleaning apparatus, so that clean water in the clean water cavity  106  can be supplied to the cleaning apparatus. 
     Referring to  FIGS.  4  to  6    and  FIG.  10   , the clean water cavity  106  is communicated with an external pipeline  152  through a water inlet channel  107 . The external pipeline  152  is capable of transporting clean water into the clean water cavity  106 . The water inlet channel  107  is provided with a one-way valve  114  having a first state and a second state. In case the one-way valve  114  is in the first state, the water in the external pipeline  152  is allowed to flow towards the clean water cavity  106 ; in case the one-way valve  114  is in the second state, the water is restricted to flow out from the water inlet channel  107 . 
     In the water tank assembly  102  of the present disclosure, when the external pipeline  152  supplies clean water to the clean water cavity  106 , the one-way valve  114  is in the first state, so that water from the external pipeline  152  is capable of being supplied to the clean water cavity  106 ; and the one-way valve  114  is in the second state when supply of clean water to the clean water cavity  106  is stopped, which can restrict the water in the water inlet channel  107  flowing out, thus the clean water in the water inlet channel  107  can be obstructed from flowing out when the external pipeline  152  is removed. 
     In some embodiments, the first state may be an open state. Under the pressure of the water flowing from the water inlet channel  107  towards the clean water cavity  106 , the one-way valve  114  is in an open state to allow water from the external pipeline  152  to be supplied to the clean water cavity  106 . 
     The second state may be a closed state, or a slightly open state (there may be a small gap). In case there is fluid in the clean water cavity  106  and the external pipeline  152  stops supplying clean water to the clean water cavity  106 , the water pressure in the clean water cavity  106  is greater than the water pressure at the water inlet channel  107 , which gives the one-way valve  114  an resistance that prevents the one-way valve  114  from further opening, making the one-way valve  114  be in a closed or nearly closed state, thus clean water in the clean water cavity  106  is obstructed from flowing out. 
     In an exemplary embodiment of the present disclosure, a water outlet end of the one-way valve  114  may include an elastic structure, and the elastic structure enables the opening of the water outlet end to be closed or nearly closed under a preset water pressure or air pressure. Illustratively, the one-way valve  114  may be a duckbill valve. 
     It should be noted that the description of “flowing out” in the embodiments of the present disclosure means that water in the clean water cavity  106  flows in the direction of the external pipeline  152  along the water inlet channel  107 , to the outside of the cleaning base station. 
     It should be understood that the water inlet channel  107  can be formed on the tank body  104 , or formed on the pipeline connected to the tank body  104 , or partially formed on the tank body  104  and partially formed on the pipeline connected to the tank body  104 . 
     In some embodiments, as shown in  FIGS.  5  and  6   , the one-way valve  114  may be a duckbill valve that includes a retractable opening for allowing the water from the external pipeline  152  flowing through and for restricting the water from the clean water cavity  106  flowing out. In case water from the external pipeline  152  flows towards the clean water cavity  106 , the opening of the duckbill valve opens under the pressure of the water flowing towards the clean water cavity  106 , thereby water can flow into the clean water cavity  106 ; in case water from the external pipeline  152  stops flowing towards the clean water cavity  106 , the opening of the duckbill valve can correspondingly contract to a nearly closed state due to its own retractable characteristics, thereby water is restricted to flow out. In particular, the fluid in the clean water cavity  106  can also gives the duckbill valve a resistance that obstructs the duckbill valve from opening further, which improves the reliability of the duckbill valve restricting the water from flowing out. For example, under normal conditions, the duckbill valve is capable of staying at a slightly open state (the second state) to restrict water back-flow, and will change to the open state (the first state) under water pressure when water from the external pipeline  152  flows towards the clean water cavity  106  through the water inlet channel  107 . When supply of water to the clean water cavity  106  is stopped, the duckbill valve will return to the slightly open state from the open state. Of course, in some other embodiments, the duckbill valve can also be in a closed state under normal conditions. 
     It should be noted that the slightly open state described in the embodiments means that the duckbill valve has a preset tiny gap at the opening under normal conditions. 
     In some embodiments, the one-way valve  114  may be a spring-type one-way valve. When clean water in the external pipeline  152  flows towards the clean water cavity  106 , the spring-type one-way valve is opened (the first state) under a pressure of the water flowing towards the clean water cavity  106 , to allow water to be transported to the clean water cavity  106 . When water in the external pipeline  152  stops flowing to the clean water cavity  106 , the spring-type one-way valve is closed (the second state) by way of its own spring force, to restrict clean water flowing out. 
     Of course, the one-way valve  114  of the present disclosure is not limited to the above-mentioned duckbill valve and spring-type one-way valve, as long as the one-way valve  114  can stay at the first state to allow clean water to flow through when clean water in the external pipeline  152  is transported to the clean water cavity  106 , and can change to the second state to restrict the water flowing out when supply of water to the clean water cavity  106  is stopped. 
     As shown in  FIGS.  4  and  5   , the water tank assembly  102  may further include an adapter  120 . The adapter  120  is configured for detachably connecting to the tank body  104  and communicating the water inlet channel  107  with the external pipeline  152 , so as to facilitate water transporting from the external pipeline  152  to the clean water cavity  106 . The adapter  120  can also facilitate the connection between the water inlet channel  107  and the external pipeline  152 . When the adapter  120  is detached from the tank body  104 , the one-way valve  114  in the water inlet channel  107  can prevent water in the water inlet channel  107  from flowing out. 
     In some embodiments, as shown in  FIGS.  5  and  6   , a water inlet pipeline structure  121  may be protruded from the bottom of the tank body  104 . The water inlet pipeline structure  121  includes a water inlet  123  and a water outlet  125 , and water in the water inlet channel  107  enters the clean water cavity  106  through the water inlet  123  and the water outlet  125  successively. 
     The water inlet pipeline structure  121  in the present disclosure is not limited to the above. For example, the water inlet pipeline structure  121  can be protruded upwards from the bottom of the tank body  104  towards the clean water cavity  106 ; the water inlet pipeline structure  121  can also be protruded from the bottom of the tank body  104  towards the direction away from the clean water cavity  106 . Of course, the water inlet pipeline structure  121  may also include a first portion protruding upwards towards the clean water cavity  106 , and a second portion protruding towards the direction away from the clean water cavity  106 , and the first portion and the second portion are communicated, etc. 
     The water tank assembly  102  further includes a water inlet connector  109 . One end of the water inlet connector  109  is connected with a first water inlet pipe  112  which is configured for connecting with the adapter  120 , and the other end of the water inlet connector  109  is connected to the water inlet  123  and communicated with the clear water cavity  106 . A first water inlet channel  113  is defined inside the first water inlet pipe  112 , a second water inlet channel  111  is defined inside the water inlet connector  109 , and the water inlet channel  107  includes the first water inlet channel  113  and the second water inlet channel  111 . 
     The first water inlet pipe  112  is communicated with the external pipeline  152  through the adapter  120 , and water in the external pipeline is transported to the clean water cavity  106  through the channel inside the adapter  120 , the first water inlet channel  113 , and the second water inlet channel  111 . When the adapter  120  is disassembled from the tank body  104 , the one-way valve  114  disposed in the water inlet channel  107  can prevent the clean water from flowing out from the first water inlet pipe  112 . 
     Of course, the water inlet channel  107  is not limited to the above, as long as it can communicate with the external pipeline  152  to transport clean water to the clean water cavity  106 . For example, the first water inlet pipe  112  may merely include a single water pipe, or may be formed by connecting at least two water pipes; the tank body  2  may also be directly connected to the pipe of the adapter  120  through the water inlet connector  109  or directly connected to the external pipeline  152 , etc. 
     It should be noted that the water inlet connector  109  may be connected to the water inlet  123  of the tank body  104  and communicated with the clean water cavity  106  through the water inlet  25 ; the water inlet connector  109  can also be directly inserted into the clean water cavity  106  through the water inlet  123  of the tank body  104 ; or the tank body  104  is provided with the water inlet pipeline structure  121  protruding in the direction away from the clean water cavity  106 , the water inlet  123  is defined at one end of the water inlet pipeline structure  121  away from the clean water cavity  106 , the water inlet pipeline structure  121  is communicated with the clean water cavity  106 , and the water inlet connector  109  is connected with the water inlet pipeline structure  121  and communicated with the clean water cavity  106  through the water inlet pipeline structure  121 , etc., which is not limited here. 
     In some embodiments, the one-way valve  114  may be a duckbill valve, and the duckbill valve is capable of being sandwiched between the water inlet  123  and the water inlet connector  109  to seal the joint of the water inlet  123  and the water inlet connector  109 . The arrangement of the duckbill valve between the water inlet  123  and the water inlet connector  109  can not only block water back-flow at the water inlet  123 , but also can seal the joint of the water inlet  123  and the water inlet connector  109 , such that there&#39;s no need for an extra sealing member to seal the joint of the water inlet  123  and the water inlet connector  109 , which simplifies the structure of the water tank assembly  102  and reduces the cost. 
     In an exemplary embodiment, as shown in  FIG.  6   , the water inlet connector  109  can be assembled to the tank body  104  through a fastener  127 . In an assembled state, the water inlet connector  109  and the tank body  104  defines an installation gap (not shown in the figures) there between for installing the duckbill valve. The duckbill valve is clamped at the installation gap for preventing the water inlet connector  109  from shaking relative to the tank body  104 , so as to achieve a sealing connection between the water inlet connector  109  and the tank body  104 . In case the duckbill valve is not installed, due to the existence of the installation gap, the water inlet connector  109  will shake when it is assembled to the tank body  104  through the fastener  127 , which can detect whether the duckbill valve is installed at the water inlet  123 . 
     In some embodiments, an outer periphery of the water inlet end of the duckbill valve may be provided with a lap portion  116  protruding outwards, a connecting portion  118  is provided at the water inlet  123 , the lap portion  116  is lapped with the connecting portion  118 , and the lap portion  116  is sandwiched between the water inlet connector  109  and the water inlet  123 . By arranging the lap portion  116  on the outer periphery of the duckbill valve, the duckbill valve can be easily clamped between the water inlet connector  109  and the water inlet  123 , which is beneficial to improve the tightness between the water inlet connector  109  and the water inlet  123 . 
     As shown in  FIG.  6   , in order to further improve the tightness of the water inlet connector  109  and the water inlet  123 , as well as the installation reliability of the duckbill valve, the lap portion  116  may be defined with a groove  117 , the connecting portion  118  may include a protrusion  119  protruding in a direction away from the clean water cavity  106 , and the protrusion  119  is engaged in the groove  117 . 
     Of course, the one-way valve  114  is not limited to the duckbill valve, nor is limited to being arranged between the water inlet connector  109  and the water inlet  123 , as long as it is positioned in the water inlet channel  107  and can restrict water in the water inlet channel  107  from flowing out when the adapter  120  is disassembled from the tank body  104 . 
     In some embodiments, the water inlet connector  109  may be a transparent or translucent member, so that it is convenient to check whether the duckbill valve is installed; or, the first water inlet pipe  112  may be a transparent or translucent member to provide a convenience for checking whether the duckbill valve is installed. 
     Of course, both the water inlet connector  109  and the first water inlet pipe  112  can be set as transparent or translucent members, or only one of them is set as transparent or translucent member. 
     Referring to  FIGS.  5  and  7   , a ball float valve  129  may be provided in the clean water cavity  106 , and a floating plug structure  130  may be provided at the water outlet  125  of the water inlet pipeline structure  121 . The ball float valve  129  is configured to move up or down according to the water level inside the clean water cavity  106 , so as to push the plug structure  130  downwards or release the plug structure  130  upwards. When the water level reaches to a preset height, the plug structure  130  moves down to block the water outlet  125 . The plug structure  130  includes a mounting body  131 , a first elastic body  132  mounted on one end of the mounting body  131  in the height direction of the mounting body  131 , and a second elastic body  133  mounted on the other end of the mounting body  131  in the height direction of the mounting body  131 . When the water level in the clean water cavity  106  gets low, the plug structure  130  does not block the water outlet  125 , so the clean water flowing towards the clean water cavity  106  from the water inlet channel  107  can normally flow into the clean water cavity  106  through the water inlet  123  and the water outlet  125 . As the water level rises, the ball float valve  129  will make a movement caused by a buoyancy of the clean water, and when the water level in the clean water cavity  106  reaches a preset height, the plug structure  130  will be pushed downwards by the ball float valve  129  to the water outlet  125  and block the water outlet  125 , to prevent the water level in the clean water cavity  106  getting too high. Further, the plug structure  130  has the first elastic body  132  and the second elastic body  133  with each installed at one end of the plug structure  130  in the height direction, each one of the first elastic body  132  and the second elastic body  133  can block the water outlet  125 , such that even though the plug structure  130  is installed reversely, it can still avoid an insufficient sealing to the water outlet  125 . 
     Further, the structure and shape of the first elastic body  132  and the second elastic body  133  may be the same, so that they can be produced by a same mold to reduce the cost. 
     The inventors found, by way of creative work, that the cleaning base station having a sewage cavity capable of discharging sewage by a water pump, the impellers of the water pump is prone to be blocked if there are large amount of impurities in the sewage, therefore, the reliability of sewage discharging is poor. In some instances, a filter screen is installed before the water pump to reduce the risk of impurities sticking to the water pump, when the sewage needs to pass through the water pump. However, in this case, since there is a large amount of impurities in the sewage, users need to clean, take care, or replace the filter screen periodically; further, the filter screen is prone to breed bacteria and stink, which will result a slightly poorer using experience. In order to solve the above-mentioned technical problems, another embodiment of the present disclosure provides a water tank assembly, as shown in  FIGS.  1  to  5 ,  8  and  9   , the present disclosure provides another base station for servicing the cleaning apparatus. The base station includes a base station body  210  and a water tank assembly  103 . The base station body  210  is provided with a cleaning system, the water tank assembly  103  includes a tank body  105 , and a sewage cavity  135  is defined in the tank body  105  to receive sewage introduced by the cleaning system. The tank body  105  is provided with a water inlet channel  108  and a sewage discharging channel  136  both communicating with the sewage cavity  135 ; the sewage cavity  135  is configured to receive the sewage coming through the water inlet channel  108  under a negative pressure introduced by an external gas source, and is configured to discharge the sewage through the sewage discharging channel  136  under a positive pressure introduced by the external gas source. 
     The water inlet channel  108  is provided with a one-way valve  115 . When the sewage cavity  135  is in a positive pressure state, the one-way valve  115  is in a closed state; when the sewage cavity  135  is in a negative pressure state, the one-way valve  115  is in an open state. 
     When external air source applies negative pressure to the sewage cavity  135 , the one-way valve  115  is in an open state, so that sewage can be sucked into the sewage cavity  135  through the water inlet channel  108 ; when sewage needs to be discharged from the sewage cavity  135 , external air source applies positive pressure to the sewage cavity  135 , so that the sewage can be discharged through the sewage discharging channel  136 , and the one-way valve  115  is in a closed state to obstruct gas in the sewage cavity  135  from leaking from the one-way valve  115  in the water inlet channel  108 , to ensure the sewage in the sewage cavity  135  can be discharged from the sewage discharging channel under the positive pressure. 
     In addition, the one-way valve  115  can also obstruct the sewage flowing out from the water inlet channel  108  under a positive pressure. It should be noted that, “flowing out” in the embodiments means that the sewage from the sewage cavity  135  flows to the cleaning system along the water inlet channel  108 . 
     It should be understood that, the tank body  105  can be defined with a gas hole to allow the external air source applying positive pressure or negative pressure to the sewage cavity  135 . The gas hole is connected to the external air source through an air pipe. The external air source can include but not limited to gas pump. If the external air source is an gas pump, the number of the gas pump is not limited to one. In some embodiments, the number of the gas pump may be two, one of which may be configured to apply positive pressure to the sewage cavity  135 , and the other may be configured to apply negative pressure to the sewage cavity  135 . 
     In some embodiments of the present application, the one-way valve  115  may be a duckbill valve. Preferably, as shown in  FIG.  8   , the duckbill valve may be vertically suspended in the tank body, and impurity particles may fall down under their own gravity, such that it can effectively reduce the risk of impurity particles getting stuck at the opening of the duckbill valve and blocking or damaging the duckbill valve. 
     When the water tank assembly  103  is installed on the base station body  210 , the water inlet channel  108  of the tank body  105  is connected to a water delivery pipeline of the cleaning system, to allow the sewage cavity  135  to receive the sewage introduced by the cleaning system. 
     It should be understood that the water inlet channel  108  can be arranged on the tank body  105 , and can also be arranged on the pipeline connected to the tank body  105 , or a portion of the water inlet channel  108  is arranged on the tank body  105  and the other portion of the water inlet channel  108  is arranged on the pipeline connected to the tank body  105 . 
     As shown in  FIG.  8    and  FIG.  9   , the one-way valve  115  is a duckbill valve. When external air source applies negative pressure to the sewage cavity  135 , the external air pressure is greater than the air pressure in the sewage cavity  135 , the retractable opening of the duckbill valve is opened so that sewage can be sucked into the sewage cavity  135 . When external air source applies positive pressure to the sewage cavity  135 , the external air pressure is less than the air pressure in the sewage cavity  135 , the retractable opening of the duckbill valve is closed so as to restrict the sewage flowing out from the water inlet channel  108 . Normally, the duckbill valve is in a slightly open state allowing gas to pass through but not water. Of course, the one-way valve  115  in the embodiments of the present disclosure is not limited to the duckbill valve, as long as it can be in an open state during the sewage cavity  135  is in a negative pressure state and a closed state during the sewage cavity  135  is in a positive pressure state. 
     In some embodiments, the one-way valve  115  may include a first duckbill valve  137  and a second duckbill valve  142  sequentially arranged along the water inputting direction. By arranging the first duckbill valve  137  and the second duckbill valve  142  in the water inlet channel  108 , it is possible to prevent the sewage flowing out from the water inlet channel  108  in case one of the first duckbill valve  137  and the second duckbill valve  142  is damaged. In addition, when positive pressure is applied to the sewage cavity  135  for draining sewage but the sewage discharging channel  136  is blocked, it is probably to cause a very high positive pressure in the sewage cavity  135 , while a sealed space defined by the first duckbill valve  137  and the second duckbill valve  142  in the water inlet pipeline structure  122  contains air, which can balance with the positive pressure in the sewage cavity  135 , such that it is beneficial to prevent the second duckbill valve  142  from upturning. 
     The one-way valve  115  is a flexible duckbill valve and is suspended, when a positive pressure is applied to the sewage cavity  135  but the sewage discharging channel  136  is blocked, it would cause a very high positive pressure in the sewage cavity  135 , which is probably to make the duckbill valve upturn under the positive pressure. In order to reduce the risk of upturning, a mounting part  149  may be provided at the water inlet channel  108  of the tank body  105  for installing the one-way valve  115 . The mounting part  149  defines a water inlet passage for water flowing through, and the duckbill valve is sleeved on the mounting part  149 . By arranging the duckbill valve on the mounting part  149 , it is beneficial to obstruct the duckbill valve from upturning by way of a resistance from the mounting part  149  when external air source applies positive pressure to the sewage cavity  135 . In addition, the arrangement of the mounting part  149  at the water inlet channel  108  can also facilitate the installation of the duckbill valve. 
     It should be noted that the duckbill valve includes a water inlet end  145 / 146  and a water outlet end  147 / 148 , the water inlet end  145 / 146  is shaped as a straight cylinder, and the water outlet end  147 / 148  has a cross-sectional area gradually decreases from the end closing to the water inlet end  145 / 146  to the end away from the water inlet end  145 / 146 . The mounting part  149  extends to the junction of the water inlet end  145 / 146  and the water outlet end  147 / 148 , so the mounting part  149  would not expand the water outlet end  147 / 148  of the duckbill valve, such that the water outlet end  147 / 148  will not be always opened which may lose the function of preventing sewage from flowing out through the water inlet channel  108 . 
     Of course, in some embodiments of the present disclosure, the duckbill valve may be arranged at different positions of the water inlet channel  108 , as long as the sewage can be restricted flowing out from the water inlet channel  108 . 
     As shown in  FIG.  8   , the one-way valve  115  includes a first duckbill valve  137 , the tank body  105  is detachably connected with a water inlet connector  110 , an end of the water inlet connector  110  closing to the sewage cavity  135  defines the mounting part  149 , and the water inlet end  145  of the first duckbill valve  137  is sleeved on the water inlet connector  110 . The water inlet end  145  of the first duckbill valve  137  can be resisted by the water inlet connector  110  since the water inlet end  145  is sleeved on the water inlet connector  110 , when positive pressure is applied to the sewage cavity  135 , it can effectively obstruct the first duckbill valve  137  from upturning by way of the resistance from the water inlet connector  110 . 
     In some embodiments, the outer periphery of the water inlet end  145  of the first duckbill valve  137  is provided with a first lap portion  138  protruding outwards, the water inlet  124  of the tank body  105  is provided with a first connecting portion  140 , and the first lap portion  138  is overlapped with the first connecting portion  140  and sandwiched between the water inlet connector  110  and the water inlet  124 , which can realize a sealed connection between the water inlet connector  110  and the water inlet  124  with no additional sealing members being used, thereby the structure of the water tank assembly  103  is simplified and the cost is reduced. 
     In some embodiments, the first lap portion  138  is recessed with a first groove  139 , the first connecting portion  140  includes a first convex portion  141  protruding in a direction away from the sewage cavity  135 , and the first convex portion  141  is engaged in the first groove  139 , which may further improve the leak profess between the water inlet connector  110  and the water inlet  124 . 
     The one-way valve  115  further includes a second duckbill valve  142  to improve the stability of restricting the sewage flowing out from the water inlet channel  108 . The tank body  105  has the water inlet pipeline structure  122 , one end of the water inlet pipeline structure  122  is communicated with the water inlet connector  110 , and the other end of the water inlet pipeline structure  122  having a water outlet  126  is protruded towards the inside of the sewage cavity  135 . The water inlet end  146  of the second duckbill valve  142  is arranged at the water outlet  126 , a bushing  150  is provided inside the water inlet pipeline structure  122 , the bushing  150  defines the mounting part  149 , and the water inlet end  146  is sleeved on the bushing  150 . 
     By arranging the first duckbill valve  137  and the second duckbill valve  142  in the water inlet channel  108 , it is possible to restrict the sewage flowing out from the water inlet channel  108  in case any one of the first duckbill valve  137  and the second duckbill valve  142  is damaged. The water inlet end  146  of the second duckbill valve  142  is sleeved on the mounting part  149  in the bushing  150 , so the water inlet end  146  can be resisted by the mounting part  149 , when external air source applies positive pressure to the sewage cavity  135 , it is beneficial to obstruct the second duckbill valve  142  from upturning by way of the resistance from the mounting part  149 . In addition, when positive pressure is applied to the sewage cavity  135  for draining sewage but the sewage discharging channel  136  is blocked, it is probably to cause a very high positive pressure in the sewage cavity  135 , while a sealed space defined by the first duckbill valve  137  and the second duckbill valve  142  arranged in the water inlet pipeline structure  122  contains air, which can balance with the positive pressure in the sewage cavity  135 , to further obstruct the second duckbill valve  142  from upturning. 
     In some embodiments, an outer periphery of the water inlet end  146  of the second duckbill valve  142  may be provided with a second lap portion  143  protruding outwards. The bushing  150  is defined with an abutting portion  151 , an inner side of the water outlet  126  is provided with a second connecting portion  144 , and the second lap portion  143  is overlapped on the second connecting portion  144  and clamped between the abutting portion  151  and the second connecting portion  144 , to realize a sealed connection between the water outlet  126  and the second connecting portion  144 , and a stable connection between the second duckbill valve  142  and the water inlet pipeline structure  122 . 
     In some embodiments, the outer periphery of the water inlet end  146  of the first duckbill valve  137  is provided with a first lap portion  138  protruding outwards, one end of the bushing  150  away from the second duckbill valve  142  defines the first connecting portion  140 , the first lap portion  138  is clamped among the water inlet  124  of the water inlet pipeline structure  122 , the bushing  150 , and the water inlet connector  110 , so as to realize a sealed connection between the water inlet connector  110  and the water inlet  124  with no additional sealing member being used, thereby the structure of the water tank assembly  103  is simplified and the cost is reduced. 
     Of course, the first connection portion  140  is not limited to being arranged on the bushing  150 . For example, the first connection portion  140  may be directly formed at one end of the water inlet pipeline structure  122  closing to the water inlet connector  110 . 
     In order to improve the stability of the connection between the water inlet connector  110  and the tank body  105 , the one-way valve  115  adopts a duckbill valve, and the water inlet connector  110  is assembled to the tank body  105  through a fastener  128 . In an assembled state, the water inlet connector  110  and the tank body  105  defines an installation gap there between for installing the duckbill valve. The duckbill valve is clamped in the installation gap to prevent the water inlet connector  110  from shaking relative to the tank body  105 , so as to achieve a sealed connection between the water inlet connector  110  and the tank body  105 . In case the duckbill valve is not installed, due to the existence of the installation gap, the water inlet connector  110  will shake when it is assembled to the tank body  105  through the fastener  128 , which can detect whether the duckbill valve is installed. 
     In some embodiments, the water inlet connector  110  may be a transparent or translucent member, so as to facilitate checking whether the duckbill valve is installed. 
     As shown in  FIGS.  3  to  9   , in an exemplary embodiment, the tank body  104  is defined with a clean water cavity  106  and a mounting cavity  134 , and the tank body  105  as a sewage tank is installed in the mounting cavity  134 . The tank body  104  is provided with a water inlet interface that communicates with the mounting cavity  134 , and the water inlet channel  108  is connected at the water inlet interface. When the tank body  104  is installed on the base station body  210 , the water inlet interface is connected to a sewage interface of the cleaning system, and the sewage discharging channel  136  is located under the tank body  105 . It should be noted that the water tank assembly  102  is not limited to this, for example, the tank body  104  may not be provided with the mounting cavity, and the tank body  105  may be directly installed on the base station body  210 ; or, the tank body  104  and the tank body  105  can be the same tank body, that is, both the clean water cavity  106  and the sewage cavity  135  are defined in the same tank body. 
     The base station may include a cleaning system for servicing the cleaning robot. For example, the cleaning system may be configured to clean the mops of the cleaning robot. The base station may be equipped with a clean water tank and a sewage tank, water in the clean water tank is supplied to the cleaning system, and the sewage tank is configured to collect the sewage generated by the cleaning system. The clean water tank may be connected to the outside, so that clean water from the outside can be inputted to the clean water tank; and the sewage tank is connected to the outside, so that sewage in the sewage tank can be discharged to the outside. 
     However, in the related art, water is usually sucked into the water tank by using an air source to apply negative pressure to the water tank, and water in the water tank is usually drained by using a water pump. As such, both gas source and water pump are needed for the water tank, which results in a complex structure. Further, in case the water quality is poor and there are many impurities in the water, the impurities are probably to damage the impeller of the water pump, and even cause the impeller to become stuck. 
     Referring to  FIG.  11   a    and  FIG.  11     b,  the present disclosure also provides a pumping and drainage system which includes: 
     a first water tank  201 , the first water tank  201  is defined with a water storage cavity C and a vent  202  communicated with the water storage cavity C; 
     a gas supply system communicated with the vent  202 ; 
     incase the gas source system is in a first state, air in the water storage cavity is discharged through the vent  202  and the gas source system successively, causing the water storage cavity C to be in a negative pressure state, so that fluid can be sucked to the water storage cavity C; in case the gas source system is in a second state, air is delivered to the water storage cavity C by the gas source system through the vent  202 , causing the water storage cavity to be in a positive pressure state, so that the fluid in the water storage cavity C can be discharged. The pumping and drainage system provided in the present disclosure can suck water and drain water automatically. The water storage cavity C of the first water tank  201  is configured for water storage (for example, store clean water or sewage). 
     It should be noted that the fluid described in the embodiments of the present disclosure may be a pure fluid, or a mixed fluid mixed with impurities such as solid particles, hair, and debris. 
     Taking  FIG.  11   a    as an example, the vent  202  of the first water tank  201  is configured for gas to output or for gas to input, the gas source system is communicated with the vent  202 , then gas can be drawn out from the water storage cavity C through the vent  202  or injected into the water storage cavity through the vent  202 . Further, the first water tank  201  has a water inlet  203  and a water outlet (not shown in the figure), and both the water inlet  203  and the water outlet communicate with the water storage cavity. The pumping and draining principle of the pumping and drainage system is: in case the gas source system is in the first state, gas in the water storage cavity C is discharged successively through the vent  202  and the gas source system, causing the water storage cavity C to be in a negative pressure state, allowing the first water tank  201  to suck water from the water inlet  203  into the water storage cavity C; in case the gas source system is in the second state, the gas source system delivers gas to the water storage cavity C through the vent  202 , causing the water storage cavity C to be in a positive pressure state, so that the first water tank  201  can discharge the water in the water storage cavity C from the water outlet. 
     In case the water storage cavity of the pumping and drainage system of the present disclosure is configured to store sewage, then it can realize an automatically collecting of sewage and automatically discharging of sewage, such that manually cleaning of sewage is no longer needed, which is very convenient and intelligent, and beneficial to improve using experience. 
     In case the water storage cavity of the pumping and drainage system of the present disclosure is configured to store clean water, then clean water can be sucked to the water storage cavity from an external water source by the gas source system, and the clean water in the water storage cavity can also be discharged by the gas source system. For example, in case the pumping and drainage system is applied to a cleaning base station, clean water may be discharged (or sprayed) to a cleaning area of the cleaning base station to clean the mops of the robot. Either the gas source system being in a first state or a second state may be determined according to the actual structure of the gas source system. The structure of the gas source system may be various, and will be described in the subsequent embodiments. 
     In some embodiments, referring to  FIGS.  11   a  and  11   b   , the gas source system may include: 
     a gas pump; 
     a reversing valve  205 , the reversing valve  205  is communicated with the gas pump and the vent  202  respectively, and includes a reversing member which can move between a first position and a second position; 
     in case the reversing member is at the first position, the gas in the water storage cavity is discharged through the vent  202 , the reversing valve  205 , and the gas pump successively, causing the water storage cavity to be in a negative pressure state; 
     in case the reversing member is at the second position, external gas is inputted into the water storage cavity through the reversing valve  205 , the gas pump, and the vent  202  successively, causing the water storage cavity to be in a positive pressure state. 
     Further, the pumping and drainage system of the present disclosure can also be configured to pump and discharge sewage without using an extra power device such as a pump, so as to realize “sewage not passing through pump”, which can effectively avoid the pump being damaged and jammed caused by impurities in the sewage, and is beneficial to improve the service life of the pump. Since there is no sewage passing through the pump, it does not need to install a filter screen before the pump, then users no longer need to clean the filter screen, which is conducive to improve using experience. 
     It should be noted that the structure, the fixing for the reversing valve  205  such as fixing mode and fixing position of the reversing valve  205  in  FIGS.  11   a  and  11   b    are only an illustrative embodiment, which is not limited to this. 
     The gas source system is composed of a gas pump and the reversing valve  205 . The gas pump is configured to provide a gas source, the reversing valve  205  is arranged between the gas pump and the first water tank  201  and communicated with the gas pump and the vent  202  respectively, and configured to switch gas circuit. 
     Compared with using a piston to realize a switching between positive pressure and negative pressure, the using of the gas pump and the reversing valve  205  to realize a switching between positive pressure and negative pressure can further adjust the gas input volume or output volume of the gas pump. When the gas input volume is greater than the gas output volume, the fluid in the sewage tank will be discharged thoroughly. Compared with using two gas pumps to realize a switching between positive pressure and negative pressure, the using of the gas pump and the reversing valve  205  to realize a switching between positive pressure and negative pressure is cost saving, and may effectively prolong the service life of the entire gas source system since the service life of the reversing valve  205  is longer than that of the gas pump. 
     The gas pump has an air inlet and an air outlet. The air inlet and the air outlet of the gas pump, and the vent  202  of the first water tank  201  may communicate with different gas holes of the reversing valve  205 . The reversing member of the reversing valve  205  moves between the first position and the second position. The reversing member is defined with gas channels that can coupled with the gas holes to make different gas holes of the reversing valve  205  be communicated, that is, when the reversing member moves to the first position or the second position, different gas holes of the reversing valve  205  will be communicated, causing the air inlet of the gas pump communicating with the vent  202 , or the air outlet of the gas pump communicating with the vent  202 . 
     It should be noted that the number of the vent  202  is not limited to one as shown in the figure. In some embodiments, the number of the vent  202  may be two, one of the vent  202  is configured to deliver the gas from the gas pump to the water storage cavity, and another vent  202  is configured for the gas in the water storage cavity to be discharged. 
     When the reversing member is at the first position, the gas in the water storage cavity is discharged through the vent  202 , the reversing valve  205 , and the gas pump successively, causing the water storage cavity to be in a negative pressure state; when the reversing member is at the second position, external gas is inputted into the water storage cavity through the reversing valve  205 , the gas pump, and the vent  202  successively, causing the water storage cavity to be in a positive pressure state. The reversing member may be a rotating part, a translational part, etc., and the reversing member may be drove by a driving member to move. In an exemplary embodiment, the driving member may include a motor which drives the reversing member to move by way of a transmission mechanism. The motor can also directly drive the reversing member to move. The structure of the transmission mechanism can be selected according to the actual situation. 
     Apart from the above described situation, the gas source system can also include other structures. For example, the gas source system may include a forward-reverse gas pump which is communicated with the vent  202  of the first water tank  201 . As the forward-reverse gas pump rotates forward, namely, the gas source system is in the first state, gas in the water storage cavity is discharged through the vent  202  and the forward-reverse gas pump successively, causing the water storage cavity to be in a negative pressure state; as the forward-reverse gas pump rotates reversely, namely, the gas source system is in the second state, the forward-reverse gas pump delivers gas into the water storage cavity through the vent  202 , causing the water storage cavity to be in a positive pressure state. For another example, the gas source system includes a cylinder-type structure which is communicated with the vent  202  of the first water tank  201 , to realize a switching between the positive pressure and negative pressure states in the water storage cavity by way of moving forward and backward. This is only exemplary, including but not limited to this. 
     In some embodiments, referring to  FIGS.  11   a  and  11   b   , the first water tank  201  includes: 
     a first tank body  206  defined with an accommodating cavity  207 ; 
     a second tank body  208  arranged in the accommodating cavity  207 , the second tank body  208  is configured for accommodating fluid (clean water or sewage); 
     the reversing valve  205  is arranged in the accommodating cavity  207 . 
     The first water tank  201  has a structure of “tank in tank”, which includes a first tank body  206  and a second tank body  208  located in the first tank body  206 . The water storage cavity and the vent  202  of the first water tank  201  are both defined in the second tank body  208 , the second tank body  208  is configured to accommodate fluid. If the water storage cavity is configured to accommodate sewage, the sewage in the second tank body  208  can be automatically discharged to the outside, so the second tank body  208  does not need a too large volume, namely, the second tank body  208  can be a small volume tank body. While the reversing valve  205  may be arranged in the first tank body  206  other than the space occupied by the second tank body  208 , and gas pipes may also be arranged in the first tank body  206 , so as to make full use of the space of the water tank, as well as not expose the gas pipe to achieve dust prevention and beauty. Optionally, the first tank body  206  is made of ABS (acrylonitrile/butadiene/styrene copolymer) material fora beautiful appearance and a good wear resistance. The second tank body  208  needs to accommodate sewage, since the sewage contains complex compositions and is prone to corrode the wall of the second tank body  208  probably caused by some chemical reactions, the second tank body  208  may be made of PP (polypropylene) material to obtain a good resistance to corrosion. 
     In addition, the water storage cavity C may be connected with a water inlet channel M and a water outlet channel N. A first controlling member is arranged at the water inlet channel M and configured to be opened during the gas source system is in the first state and to be closed during the gas source system is in the second state; and a second controlling member is arranged at the water outlet channel N and configured to be closed during the gas source system is in the first state and to be opened during the gas source system is in the second state. 
     In some embodiments, the first controlling member may be a one-way valve or a globe valve; in some embodiments, the second controlling member may be a one-way valve or a globe valve. In an exemplary embodiment, as shown in  FIG.  11   b   , the first controlling member is a one-way valve (specifically, a duckbill valve M 1 ), and is arranged at the water inlet  203  of the water inlet channel M. The duckbill valve can be opened when bearing one-way pressure. The direction of the one-way pressure for opening the duckbill valve M 1  at the water inlet channel M is consistent with the water input direction of the water inlet channel M. When water in the water storage cavity C needs to be discharged, gas is introduced into the water storage cavity C by the gas source system applying a positive pressure, and the duckbill valve M 1  is in a closed state under the air pressure in the water storage cavity C, ensuring the fluid in the water storage cavity C being pushed by the air pressure to the water outlet channel N to be discharged. Similarly, the second controlling member may also be a duckbill valve disposed in the water outlet channel N. When water is needed to be pumped to the water storage cavity C, the gas source system will apply negative pressure to the water storage cavity C, under an external air pressure, the duckbill valve at the water outlet channel N is in a closed state, and gas in the water storage cavity C is pumped away by the gas source system to cause the water storage cavity C to be in a negative pressure state, such that external fluid is capable of being drawn into the water storage cavity C through the water inlet channel M. 
     Of course, in some other embodiments, the first controlling member may be arranged at any other positions of the water inlet channel M, and the second controlling member may be arranged at any other positions of the water outlet channel N. 
     In some other embodiments, the pumping and drainage system may include a flexible water inlet pipe (not shown in the figure), the above-mentioned water inlet channel M is defined in the flexible water inlet pipe, and the first controlling member is configured to control radial contraction or relaxation of the flexible water inlet pipe to open or close the water inlet channel M. Similarly, the pumping and drainage system may include a flexible water outlet pipe, the water outlet channel N is defined in the flexible water outlet pipe, and the second controlling member is configured to control radial contraction or relaxation of the flexible water outlet pipe to open or close the water outlet channel N. In an exemplary embodiment, the flexible water inlet pipe and the flexible water outlet pipe may be silicone tubes, the first controlling member and the second controlling member may be the power members capable of clamping or squeezing the flexible water inlet and outlet pipes along the radial direction of the flexible water inlet and outlet pipes, so that the water inlet channel M and the water outlet channel N can be opened or closed. The specific structures of the first controlling member and the second controlling member can be designed according to actual needs, which are not limited here. 
     As shown in  FIGS.  11   c  to  11   e   , the first water tank  201  may be provided with a filtering member  204  arranged corresponding to the vent. The filtering member  204  is configured to obstruct solid matter from entering the vent  202  and allow gas to enter the vent  202  from the filtering member  204  (as shown in  FIG.  11   e   , the dotted arrow shows the flow path of the gas entering the vent  202  from the water storage cavity C). 
     In an exemplary embodiment, the filtering member  204  may be fixed in the first water tank  201 , and the edge of the first water tank  201  may be in contact with, or abuts against, the housing of the first water tank  201 , so that gas in the water storage cavity C can substantially pass through the filtering member  204  first and then enter the vent  202 , so as to block the solid matter at the filtering member  204  as much as possible, to reduce the risk of solid matter entering the vent  202  and then entering the gas source system and damaging the gas source system. 
     The filtering member  204  may be a filtering screen, or other filtering devices that can allow gas to pass through, but can block solid substances from passing through. It should be noted that, with a certain number of through holes, the smaller the pore size of the through hole of the filtering screen, the stronger the ability of blocking solid substances, but the worse the ventilation performance; the larger the pore size of the through hole, the poorer the ability of blocking solid substances, but the better the ventilation performance. Those skilled in the art can select according to the actual needs, which is not limited here. 
     The present disclosure also provides a base station which includes a base station body  210  and the pumping and drainage system described in the foregoing embodiments. The first water tank  201  is installed on the base station body  210 . The structure of the pumping and drainage system can refer to the above-mentioned embodiments. Since the base station adopts the technical solutions of the above-mentioned embodiments, it has at least all the technical effects brought by the technical solutions of the above-mentioned embodiments, which is not repeated here. 
     In some other embodiments, the gas pump and the reversing valve  205  are both arranged on the base station body  210 . The base station body  210  is provided with at least one interface; 
     the vent  202  communicates with the reversing valve  205  through the interface. 
     At the base station body  210 , the interface is communicated with the reversing valve  205 , and the reversing valve is connected with the gas pump. The reversing valve is connected to the gas inlet and the gas outlet of the gas pump through different gas holes of the reversing valve, and the reversing valve is also provided with an exhaust hole for communicating with atmosphere. During the gas pump is in working, the gas flow direction is switched and controlled by the reversing valve  205 , gas flows into the gas pump through the interface of the base station body  210 , the reversing valve  205 , and the gas inlet of the gas pump successively, and then the gas flows to the reversing valve  205  from the gas outlet of the gas pump to flow out through the reversing valve  205 ; or, gas enters the gas pump from the reversing valve  205  and the gas inlet of the gas pump, then flows out through the gas outlet of the gas pump, the reversing valve  205 , and the interface of the base station body  210  successively. In case the base station body  210  is installed with the first water tank  201 , the vent  202  may communicate with the reversing valve  205  through the interface. The base station body  210  switches the gas circuit by using the reversing valve  205 , which can form a negative pressure gas circuit at the interface, causing the water storage cavity to be in a negative pressure state for drawing water; or, form a positive pressure gas circuit at the interface, causing the water storage cavity to be in a positive pressure state for draining water. 
     In some embodiments, referring to  FIGS.  12  to  14     b ,  FIGS.  16   g  and  16   h   , the base station may further include a second water tank  2001 . The second water tank  2001  may be an ordinary water tank which cannot automatically pump and drain water. 
     The second water tank  2001  is configured for manually adding clean water and/or removing sewage. In other words, the second water tank is a conventional water tank (it cannot automatically pump water and/or automatically discharge water during in use), it requires users to manually add clean water or remove the sewage therein, at the time before or after use. 
     The first water tank  201  and the second water tank  2001  can be alternatively installed to the base station body  210 . 
     In some embodiments, referring to  FIGS.  11   a  to  14   a    , the reversing valve  205  is arranged on the first water tank  201 , and a gas pump Q is arranged on the base station body  210 ; 
     the base station body  210  is provided with at least two interfaces, one of which defines a positive pressure interface  211 , and the other defines a negative pressure interface  212 ; 
     in case the first water tank  201  is installed on the base station body  210 , the positive pressure interface  211  is communicated with the reversing valve  205  and the gas outlet of the gas pump, and the negative pressure interface  212  is communicated with the reversing valve  205  and the gas inlet of the gas pump. 
     Both the positive pressure interface  211  and the negative pressure interface  212  are connected to the gas pump at the base station body  210 . The negative pressure interface  212  is coupled to the gas inlet of the gas pump, and the positive pressure interface  211  is coupled to the gas outlet of the gas pump. During the gas pump is working, gas passes through the negative pressure interface  212  and the gas inlet of the gas pump to flow into the gas pump, then flows to the positive pressure interface  211  from the gas outlet of the gas pump, and then flows out through the positive pressure interface  211 . When the base station body  210  is installed with the first water tank  201 , the positive pressure interface  211  is communicated with the reversing valve  205  and the gas outlet of the gas pump, the negative pressure interface  212  is communicated with the reversing valve  205  and the gas inlet of the gas pump, and the vent  202  of the first water tank  201  is communicated with the reversing valve  205 . In the first water tank  201 , the reversing valve  205  is arranged to switch gas circuit, causing the vent  202  to be communicated to the negative pressure gas circuit corresponding to the negative pressure interface  212 , to allow the water storage cavity to be in a negative pressure state for water inputting; or causing the vent  202  to be communicated to the positive pressure gas circuit corresponding to the positive pressure interface  211 , to allow the water storage cavity to be in a positive pressure state for water discharging. 
     As shown in  FIG.  15   a    to  FIG.  15   e   , the positive pressure interface  211  is provided with a gas inlet  213  that communicates with the gas outlet of the gas pump, and a docking port  215  for docking with the first water tank  201 . The gas inlet  213  communicates with the docking port  215 ; 
     when the first water tank  201  is installed on the base station body  210 , the negative pressure interface  212  is communicated with the first water tank  201 , and the docking port  215  of the positive pressure interface  211  is in an open state to connect and communicate with the first water tank  201 ; 
     when the second water tank  2001  is installed on the base station body  210 , the negative pressure interface  212  is communicated with the second water tank  2001 , and the positive pressure interface  211  is communicated to the atmosphere. 
     In some embodiments, when the second water tank  2001  is installed on the base station body  210 , the docking port  215  of the positive pressure interface  211  may be in a closed state. Specifically, the outer wall of the second water tank  2001  can be arranged to cover the docking port  215 , or the second water tank  2001  includes a certain component configured to close the docking port  215 , to make the docking port  215  be in a closed state. Or, a certain covering member may be movably arranged at the docking port  215  to open or close the docking port  215 . 
     Referring to  FIGS.  11   a ,  11   b   , and  12 , and a gas circuit schematic diagram as shown in  FIG.  14   a   , when the base station body  210  is installed with the first water tank  201 , the negative pressure interface  212  is communicated to the first water tank  201 , and the docking port  215  of the positive pressure interface  211  is in an open state and is in communication with the first water tank  201 . During the gas pump is working, the gas pump draws gas from the negative pressure interface  212  or exhausts gas to the docking port  215  of the positive pressure interface  211 , to provide negative pressure or positive pressure to the first water tank  201 . By using the reversing valve  205  to switch gas circuit, the first water tank  201  can select to communicate the negative pressure gas circuit corresponding to the negative pressure interface  212  to cause the water tank to be in a negative pressure state for water inputting; or select to communicate the positive pressure gas circuit corresponding to the positive pressure interface  211  to cause the water tank to be in a positive pressure state for water discharging. 
     Referring to  FIG.  12    and a gas circuit schematic diagram as shown in  FIG.  14   b   , when the second water tank  2001  is installed on the base station body  210 , the negative pressure interface  212  is communicated to the second water tank  2001 , the docking port  215  of the positive pressure interface  211  is in a closed state, the gas pump draws gas from the negative pressure interface  212  during in working to provide negative pressure to the second water tank  2001 , causing the second water tank  2001  to be in a negative pressure state for water inputting. 
     As shown in  FIG.  16   h   , the second water tank  2001  may include a clean water tank  2001   a  and a sewage tank  2001   b,  the clean water tank  2001   a  may be provided with a clean water waterway interface O 1 , the sewage tank  2001   b  may be provided with a sewage waterway interface O 2  and a vent O, when the second water tank  2001  is installed on the base station body  210 , the clean water waterway interface O 1  of the second water tank  2001  is connected and communicated with a water outlet connector  2114  on the base station body  210 , and the sewage waterway interface O 2  is connected and communicated with a water inlet connector  214  on the base station body  210 . The vent O of the second water tank  2001  is communicated with the negative pressure interface  212  on the base station body  210 . 
     The base station body  210  includes a housing, optionally, the gas pump may be installed in the housing or be installed at an outer side of the housing, and the negative pressure interface  212  and the positive pressure interface  211  may be arranged on the surface of the housing, corresponding to the positions where the first water tank  201  and the second water tank  2001  are mounted on the base station body  210 . By this way, when the first water tank  201  is installed on the base station body  210 , the first water tank  201  is connected and communicated to the negative pressure interface  212  and the docking port  215  of the positive pressure interface  211 ; when the second water tank  2001  is installed on the base station body  210 , the second water tank  2001  is connected and communicated to the negative pressure interface  212 . In addition, the opening or closing of the docking port  215  of the positive pressure interface  211  may be achieved in various ways, for example, a cover plate adapted to the docking port  215  may be provided to block the docking port  215  to make the docking port  215  be closed, correspondingly, by removing the cover plate, the docking port  215  can be opened. Of course, this is only an illustrative embodiment, including but not limiting to this. The base station body  210  of the present disclosure can apply gas source to both the first water tank  201  and the second water tank  2001 , that is, the first water tank  201  and the second water tank  2001  may share the gas source in the base station body  210 , such that there is no need to set an additional gas source for the first water tank  201 , which simplifies the structure and reduces the cost. 
     In some embodiments, referring to  FIGS.  11   a ,  11   b   ,  12 , and  14   a , the first water tank  201  has a water inlet  203  and a water outlet, the reversing valve  205  is respectively connected to the negative pressure interface  212 , the positive pressure interface  211 , the vent  202 , and the atmospheric environment. 
     In case the negative pressure interface  212 , the reversing valve  205  and the vent  202  are communicated, and the positive pressure interface  211  and the reversing valve  205  are communicated to the atmospheric environment, negative pressure would be formed inside the water storage cavity of the first water tank  201  for the first water tank  201  to store water through the water inlet; 
     in case the positive pressure interface  211 , the reversing valve  205  and the vent  202  are communicated, and the negative pressure interface  212  and the reversing valve  205  are communicated to the atmospheric environment, positive pressure would be formed inside the water storage cavity of the first water tank  201  for the first water tank  201  to discharge water through the water outlet. 
     Apart from the vent  202 , the first water tank  201  also includes the water inlet  203  and a water outlet  217 . The water inlet  203  of the first water tank  201  is configured to communicate with the water inlet connector  214  of the base station body  210  through a water inlet pipe. Optionally, the reversing valve  205  may be communicated to the negative pressure interface  212  of the base station body  210  through a negative pressure suction pipe  219 , communicated to the positive pressure interface  211  of the base station body  210  through a positive pressure gas inlet pipe  220 , communicated to the vent  202  of the first water tank  201  through a vent pipe  221 , and communicated to the atmospheric environment through an exhaust pipe  222 . 
     The first water tank  201  communicates to a negative pressure gas circuit corresponding to the negative pressure interface  212 , that is, the negative pressure interface  212 , the reversing valve  205 , and the vent  202  are communicated (namely, the negative pressure suction pipe  219  is communicated to the vent pipe  221 );and the positive pressure interface  211  and the reversing valve  205  are communicated to the atmospheric environment (namely, the positive pressure gas inlet pipe  220  is communicated to the exhaust pipe  222 ).Gas in the water storage cavity C of the first water tank  201  passes through the vent  202 , the vent pipe  221 , the reversing valve  205  and the negative pressure suction pipe  219  successively to enter the negative pressure interface  212 , then the gas enters the positive pressure interface  211  through the gas pump to further pass through the positive pressure gas inlet pipe  220 , the reversing valve  205 , and the exhaust pipe  222  to enter atmospheric environment. At the same time, negative pressure is formed inside the water storage cavity C of the first water tank  201 , so that water can be pumped to the water storage cavity C of the first water tank  201  through the water inlet  203 ; 
     alternatively, the first water tank  201  is communicated to a positive pressure gas circuit corresponding to the positive pressure interface  211 , that is, the positive pressure interface  211 , the reversing valve  205 , and the vent  202  are communicated (namely, the positive pressure gas inlet pipe  220  communicates with the vent pipe  221 ), the negative pressure interface  212  and the reversing valve  205  are communicated to the atmospheric environment (namely, the negative pressure suction pipe  219  is communicated to the exhaust pipe  222 ). Gas in the atmospheric environment enters the negative pressure interface  212  through the exhaust pipe  222 , the reversing valve  205 , and the negative pressure suction pipe  219 , then enters the positive pressure interface  211  through the gas pump, and then enters the water storage cavity C of the first water tank  201  through the positive pressure gas inlet pipe  220 , the reversing valve  205 , the vent pipe  221 , and the vent  202  successively. At the same time, positive pressure is generated inside the first water tank  201 , so that fluid in the water storage cavity C of the first water tank  201  can be discharged through the water outlet  217 . 
     In some embodiments, referring to  FIGS.  13 ,  15     a , and  15   b , the positive pressure interface  211  may further be provided with an exhaust port  216  communicated with the gas inlet  213 ; 
     when the first water tank  201  is installed on the base station body  210 , the exhaust port  216  is in a closed state, and gas from the gas pump enters the first water tank  201  from the gas inlet  213 , the docking port  215 , and the reversing valve  205 ; 
     when the second water tank  2001  is installed on the base station body  210 , gas from the gas pump is discharged into the atmosphere through the gas inlet  213  and the exhaust port  216 . 
     In some other embodiments, as shown in  FIG.  15   d    to  FIG.  15   e   , the exhaust port  216  may be omitted. When the second water tank  2001  is installed on the base station body  210 , gas from the gas pump enters the positive pressure interface from the gas inlet  213 , and then flows directly to the atmosphere from an upper opening of the positive pressure interface. 
     When the first water tank  201  is installed on the base station body  210 , the exhaust port  216  is closed, and gas from the gas pump enters the first water tank  201  from the gas inlet  213 , the docking port  215 , and the reversing valve  205 . In the current state, the exhaust port  216  is closed, which ensures that the gas entering to the positive pressure interface  211  through the gas inlet  213  can be transported to the first water tank  201  through the docking port  215 . Then, the first water tank  201  switches the gas circuit through the reversing valve  205 , to select communicating the negative pressure gas circuit corresponding to the negative pressure interface  212 , causing the water tank to be in a negative pressure state to suck water; or select communicating the positive gas circuit corresponding to the positive pressure interface  211 , causing the water tank to be in a positive pressure state to discharge water. When the second water tank  2001  is installed on the base station body  210 , gas from the gas pump may be discharged into the atmosphere from the gas inlet  213  and the exhaust port  216 . The gas transported by the gas pump to the positive pressure interface  211  can be released to the atmospheric environment through the exhaust port  216 , which ensures a normal work of the gas pump. The opening or closing of the exhaust port  216  may be realized in various ways. For example, when the first water tank  201  is installed on the base station body  210 , the gas inlet connector on the first water tank  201  for docking with the positive pressure interface  211  may close the exhaust port  216 . Alternatively, a cover plate or the like adapted to the exhaust port  216  may be provided to block the exhaust port  216  to make the exhaust port  216  be in a closed state. Correspondingly, removing the cover plate can open the exhaust port  216 . It should be understood that, this is only illustrative, including but not limiting to this. 
     In some embodiments, referring to  FIGS.  15   a  to  15   c   , the positive pressure interface  211  further includes a concave portion U defined on the base station body  210 , and the concave portion U defines a communicating cavity  218 ; 
     the communicating cavity  218  is configured to communicate with the gas inlet  213 , the docking port  215 , and the exhaust port  216  respectively; 
     in case the second water tank  2001  is installed on the base station body  210 , gas from the gas pump first enters the communicating cavity  218  from the gas inlet  213 , and then is discharged into atmosphere through the exhaust port  216  (the dashed arrow in  FIG.  15   b    shows a gas flow path in the positive pressure interface  211 , in the case the second water tank  2001  is installed on the base station body  210 ). 
     When the first water tank  201  is installed on the base station body  210 , the docking port  215  is in an open state (as shown in  FIG.  15   c   ), the exhaust port  216  is in a closed state, and gas from the gas pump enters the first water tank  201  from the gas inlet  213 , the docking port  215 , and the reversing valve  205  (the dashed arrow in  FIG.  15   c    shows a gas flow path in the positive pressure interface  211 , in the case the first water tank  201  is installed on the base station body  210 ). When the second water tank  2001  is installed on the base station body  210 , the docking port  215  of the positive pressure interface  211  is in a closed state, the exhaust port  216  is in an open state, and gas from the gas pump enters the communicating cavity  218  through the gas inlet  213  and then be discharged into atmosphere through the exhaust port  216 . 
     In some embodiments, referring to  FIG.  15   b   , the maximum cross-sectional area of the gas channel of the gas inlet  213  is smaller than the maximum cross-sectional area of the gas channel of the communicating cavity  218 , and the maximum cross-sectional area of the gas channel of the communicating cavity  218  is larger than the maximum cross-sectional area of the gas channel of the exhaust port  216 . 
     The cross-sections of the gas channels of the gas inlet  213 , the communicating cavity  218 , and the exhaust port  216  are all perpendicular to the flow direction of the gas. The gas from the gas pump enters the communicating cavity  218  through the gas inlet  213  (the cross-section of the gas channel changes from small to large), and then flows to the exhaust port  216  from the communicating cavity  218  (the cross-section of the gas channel changes from large to small) to be discharged into the atmosphere. After several times of the changing of the cross-sectional area of the gas channel, gas sound wave is reflected at the position where the cross-section abruptly changes and noise is attenuated, thereby a noise reduction of the gas is achieved. Therefore, the positive pressure interface  211  may achieve noise reducing by way of designing a reasonable structure for it. 
     In some embodiments, referring to  FIGS.  15   b  to  16   d   , the docking port  215  is a concave docking port  215 , the first water tank  201  includes a protruding gas inlet connector  209 , and the gas inlet connector  209  can be inserted into the concave docking port  215  to communicate with the concave docking port  215 ; or, 
     as shown in  FIGS.  16   a  and  16   b   , the docking port  215  is a convex docking port  215 . The convex docking port  215  is located in the concave portion, and protrudes upwards from the bottom of the concave portion, the first water tank  201  includes a convex gas inlet connector  209 , and the convex docking port  215  can be inserted into the gas inlet connector  209  to communicate with the gas inlet connector  209 . 
     The docking port  215  for the first water tank  201  and the positive pressure interface  211  can be a convex docking structure or a concave docking structure. As shown in  FIG.  15   b    and  FIG.  15   c   , the gas inlet connector  209  provided to the first water tank  201  is a convex gas inlet connector, which can be engaged to the concave docking port  215  of the positive pressure interface  211  to communicate with the concave docking port  215 . Alternatively, the docking port  215  for the first water tank  201  and the positive pressure interface  211  can be a concave docking structure or a convex docking structure. As shown in  FIG.  16   b    to  FIG.  16   d   , the gas inlet connector  209  provided to the first water tank  201  is a convex gas inlet connector  209 , which can be engaged to the convex docking port  215  of the positive pressure interface  211  to communicate with the convex docking port  215 . It can select one of the two docking structures according to an actual situation. 
     Similarly, when the docking port is a convex docking port  215 , as shown in  FIGS.  16   e    to  16   f , the exhaust port  216  of the positive pressure interface may also be omitted. When the second water tank  2001  is installed on the base station body  210 , gas from the gas pump will enter the positive pressure interface from the gas inlet  213 , and then flows directly to the atmospheric environment through an upper opening of the positive pressure interface. 
     In some embodiments, referring to  FIGS.  15   c  and  16   d   , the base station body  210  is further provided with a sealing member  223 , and the sealing member  223  may be positioned between the docking port  215  and the gas inlet connector  209 . 
     The sealing member  223  is configured to realize a sealing between the first water tank  201  and the positive pressure interface  211  to ensure a gas tightness, and prevent gas from leaking from the gap between the first water tank  201  and the positive pressure interface  211 . Wherein, the sealing member  223  may have different structures corresponding to a concave docking port  215  or a convex docking port  215  of the positive pressure interface  211 . 
     Further, referring to  FIG.  15   c   , in case the docking port  215  is a concave docking port  215 , the sealing member  223  may be sleeved on an outer peripheral wall of the gas inlet connector  209 , and abutted the inner side wall of the concave docking port  215 ; 
     as shown in  FIG.  16   d   , in case the docking port  215  is a convex docking port  215 , the sealing member  223  is arranged on an inner peripheral wall of the gas inlet connector  209 , and abutted the outer side wall of the convex docking port  215 . 
     As shown in  FIG.  15   c   , in case the docking port  215  is the concave docking port  215 , the sealing member  223  is sleeved on the gas inlet connector  209 , so that when the gas inlet connector  209  is coupled with the concave docking port  215 , the sealing member  223  resists against the inner side wall of the concave docking port  215 , which prevents the gas in the positive pressure interface  211  introduced by the gas pump from leaking to the atmospheric environment from the gap between the outer peripheral wall of the gas inlet connector  209  and the inner side wall of the concave docking port  215 , thereby gas tightness is ensured. As shown in  FIG.  16   d   , in case the docking port  215  is the convex docking port  215 , the sealing member  223  is arranged on the inner peripheral wall of the gas inlet connector  209 , so that when the gas inlet connector  209  is coupled with the convex docking port  215 , the sealing member  223  resists against the outer side wall of the convex docking port  215 , which prevents the gas in the positive pressure interface  211  introduced by the gas pump from leaking to the atmosphere from the gap between the outer peripheral wall of the convex docking port  215  and the inner side wall of the gas inlet connector  209 . 
     Further, as shown in  FIG.  15   c   , the docking port  215  is a concave docking port  215 , the sealing member  223  may be provided with a plurality of annular protrusions  224  protruded on an outer peripheral wall of the sealing member  223 , and the annular protrusions  224  resist against the inner side wall of the concave docking port  215 ; 
     as shown in  FIG.  16   d   , the docking port  215  is a convex docking port  215 , the sealing member  223  may be provided with a plurality of annular protrusions  224  protruded on an inner peripheral wall of the sealing member  223 , and the annular protrusions  224  resist against the outer side wall of the convex docking port  215 . 
     The sealing member  223  is provided with a plurality of annular protrusions  224 , the plurality of annular protrusions  224  are arranged at intervals on the outer peripheral wall of the sealing member  223 , and may be integrally formed with the sealing member  223 . When the gas inlet connector  209  is coupled with the docking port  215 , the sealing member  223  resists against the side wall of the docking port  215  by way of the annular protrusions  224 , which can achieve a multi-stage sealing to further improve the gas tightness. 
     In some embodiments, referring to  FIG.  15   c   , the docking port  215  is a concave docking port  215 , the sealing member  223  is defined with an extending portion  225  which is located at an end of the sealing member  223  facing the concave docking port  215 , the extending portion  225  and the concave docking port  215  cooperatively defines a deformation cavity O between the extending portion  225  and an inner side wall of the concave docking port  215 . The extending portion  225  deforms towards the deformation cavity O when there is gas passing through. 
     In an exemplary embodiment, the extending portion  225  of the sealing member  223  may have a shape like a hollow round table which extends and converges towards the centerline of the sealing member  223 . As shown in  FIG.  15   c   , when gas from the gas pump enters into the positive pressure interface  211 , the extending portion  225  of the sealing member  223  deforms towards the deformation cavity O due to a pressure from the gas, which has a tendency to cling to the inner side of the concave docking port  215 , which can further improve the gas tightness. 
     In some embodiments, referring to  FIGS.  12 ,  15     b , and  16   b , the base station body  210  further includes: 
     a covering member  226 , the covering member  226  is movably or detachably connected to the docking port  215  to close or open the docking port  215 . 
     When the first water tank  201  is installed on the base station body  210 , the covering member  226  is removed to open the docking port  215 , allowing the first water tank  201  to be connected and communicated with the docking port  215 , then gas can be supplied to the first water tank  201  through the positive pressure interface  211 ; when the second water tank  2001  is installed on the base station body  210 , the covering member  226  closes the docking port  215  since the second water tank  2001  does not need to communicate to the positive pressure interface  211 . 
     Optionally, the covering member  226  can be movably connected with the docking port  215  in various ways. For example, the covering member  226  is a cover plate, and is slidably or rotatably arranged at the docking port  215 , which is not limited here; or, the covering member  226  may be detachably connected to the docking port  215  in various ways, for example, the covering member  226  is a cover plate connected to the docking port  215  by buckle or fasteners; or, the covering member  226  is a rubber plug interference fitting with the docking port  215 , which is not limited here. 
     In some embodiments, referring to  FIGS.  15   b  and  16   b   , the covering member  226  is configured to be installed at the opening of the concave portion, to obstruct gas from flowing out of the docking port  215 , allowing the gas from the gas inlet  213  to pass through the communicating cavity  218  and then to be discharged from the exhaust port  216 . 
     In some embodiments, the covering member  226  includes a rigid member and/or an elastic plug, it can be selected according to actual need. Further, there is no restriction to the shape of the covering member  226 . 
     The present disclosure also provides a cleaning system, which includes the base station and the cleaning apparatus as described in the foregoing embodiments. The structure of the base station can be referred to the above-mentioned embodiments. Since the cleaning system adopts all the technical solutions of the above-mentioned embodiments, it has at least all the technical effects brought by the technical solutions of the above-mentioned embodiments, which is not repeated here. 
     By way of creative work, the inventor found that gas source can be used as a power source to realize an automatic suction and drainage for the water tank. Gas pipes and valves are arranged between the gas source and the water tank, the valves are configured to switch gas circuit of the gas pipes, sewage can be sucked when negative pressure is applied by the gas source, and the sewage can be discharged when positive pressure is applied by the gas source. 
     Two two-position three-way solenoid valves are commonly used to control the switch of gas circuit in the gas pipelines of the water tank, which is not only high cost, but also results in a complicated arrangement of the gas pipelines. As a result, the gas pipelines are prone to be installed incorrectly to affect a normal use. 
     Referring to  FIGS.  17  to  19   , the present disclosure further provides a reversing valve  301 . The reversing valve  301  includes: 
     ahousing  302 , a surface of the hosing  302  is defined with at least four gas holes  303 ; 
     a reversing member  304  movably arranged in the housing, the reversing member  304  is defined with at least two independent channels  305 , and each channel  305  communicates with two of the gas holes  303 ; 
     a driving member  306  arranged on the housing  302  and is in driving connection with the reversing member  304 . The driving member  306  drives the reversing member  304  to move to switch the communication between the channel  305  and different gas holes  303 . 
     The reversing valve  301  of the embodiment can be applied to the base station of the cleaning system to switch gas circuit of the water tank, causing the water tank to be in a negative pressure state for water inputting or in a positive pressure state for water discharging. Of course, the reversing valve  301  can also be applied in other application scenarios. The housing  302  of the reversing valve  301  may include a first housing and a second housing which are detachably connected with each other. The first housing and the second housing are coupled together and cooperatively define an inner accommodating cavity. Screws and buckled can be used to detachably connect the first housing and the second housing, which can be selected according to actual need. 
     The reversing member  304  is located in the accommodating cavity of the housing  302 , the gas holes  303  of the housing  302  is configured for connecting with external gas pipes and penetrate into the housing  302  for communicating with the channel  305  of the reversing member  304 . The channel  305  has an opening defined on a surface of the reversing member  304 , for the channel  305  to communicate with the gas hole  303  inside the housing  302 . There are at least four gas holes  303  and at least two channels  305 , the two channels  305  are independent with each other, and each channel  305  communicates with two of the gas holes  303 . That is, the number of gas holes  303  may be four, six, or eight. For example, in case there are four gas holes  303 , two channels  305  may be provided correspondingly, one channel  305  communicates with two adjacent gas holes  303 , and the other channel  305  communicates with the other two adjacent gas holes  303 . In case there are six gas holes  303 , three channels  305  may be provided correspondingly, adjacent two of the six gas holes  303  form a pair of gas holes, and the three pairs of gas holes are respectively communicated with one of the channels  305 . Eight or other numbers of gas holes can be set according to this. By way of the channel  305 , each two gas holes  303  are communicated, gas flowing in one of the gas holes  303  may flow through the channel  305  to the other gas hole  303  and then flow out. 
     The driving member  306  drives the reversing member  304  to move, so the channel  305  of the reversing member  304  changes positions correspondingly, thereby switching the communication between the channel  305  and different gas holes  303 . The reversing member  304  may rotate to make a movement, or make a translational movement (i.e., parallel translation). For example, in case the reversing member  304  is rotated to make a movement, the gas holes  303  may be arranged at intervals on the housing  302  along a circumferential direction of the housing  302 , and the channels  305  are correspondingly arranged in the reversing member  304  in turn along the circumferential direction; correspondingly, the driving member  306  may be a motor or other power source which drives the reversing member  304  through a gear set or a worm gear or a transmission belt. In case the reversing member  304  makes a parallel translation, the gas holes  303  on the housing  302  may be arranged at intervals in a straight line, the channels  305  are correspondingly arranged in a straight line in the reversing member  304 , and the driving member  306  maybe a cylinder or a motor or other power source. In case a motor is selected, the driving member  306  may drive the reversing member  304  through a leading screw or a gear and rack or a friction wheel. In addition, no matter what kind of movement of the reversing member  304  makes and what kind of transmission structures is used, the motor as the driving member  306  may be fixed on the housing  302  or fixed on the reversing member  304 , which can be selected according to an actual need. 
     The principle of switching the gas circuit of the reversing valve  301  is: a channel  305  in the reversing member  304  of the reversing valve  301  communicates with two of the gas holes  303 , thereby two gas pipes with each connecting to one of the two gas holes  303  communicates with each other; the driving member  306  of the reversing valve  301  drives the reversing member  304  to move to change the position of the channel  305 , thereby switching off at least one of the two gas holes  303  that is communicated with the channel  305 , making the channel  305  to communicate with another gas hole  303 . As such, different gas pipes can be switched to be communicated to realize gas circuit switching. 
     When the reversing valve  301  is applied to the base station of the cleaning system, the gas pipeline, which is configured for the water tank, includes the positive pressure gas inlet pipe, the vent pipe, the negative pressure suction pipe, and the exhaust pipe, one end of each of the four is connected to one of the four different gas holes  303  of the reversing valve  301 , and the other end of the positive pressure gas inlet pipe is configured for gas inputting, the other end of the vent pipe is connected to the water tank, the other end of the negative pressure suction pipe is configured for gas outputting, and the other end of the exhaust pipe is communicated to the atmospheric environment. 
     The gas circuit is switched by the reversing valve  301 , the negative pressure suction pipe is communicated with the vent pipe, the positive pressure gas inlet pipe is communicated with the exhaust pipe, gas in the water tank enters the negative pressure suction pipe through the vent pipe and the reversing valve  301  successively, causing a negative pressure to be formed inside the water tank for water inputting; gas in the positive pressure gas inlet pipe passes through the reversing valve  301  and the exhaust pipe successively to be discharged into the atmospheric environment; 
     when the positive pressure gas inlet pipe is communicated with the vent pipe and the negative pressure suction pipe is communicated with the exhaust pipe, gas in the positive pressure gas inlet pipe enters the water tank through the reversing valve  301  and the vent pipe successively, causing a positive pressure to be formed inside the water tank for water discharging; gas in the atmospheric environment enters the negative pressure suction pipe through the exhaust pipe and the reversing valve  301  successively. 
     A single valve of the present disclosure will solve the problems solved by the existing two two-position three-way solenoid valves, which reduces the number of the valve and reduces the cost. Further, the reversing valve  301  only needs to connect the positive pressure gas inlet pipe, the vent pipe, the negative pressure suction pipe and the exhaust pipe, such that the number of pipes of the pipeline is reduced, the arrangement for the pipeline becomes simple and misfitting will be reduced, and the cost is further reduced. 
     In some embodiments, referring to  FIGS.  18  and  19   , the reversing member  304  includes: 
     a mounting shaft  307 , rotatably arranged in the housing  302 ; 
     a turnplate  308 , mounted on the mounting shaft  307 , and the turnplate  308  is defined with at least two channels  305  on the surface of the turnplate  308 ; 
     the at least four gas holes  303  are arranged at intervals and around the axis of the mounting shaft  307  on the surface of the housing  302 . 
     The reversing member  304  is a rotating structure, the mounting shaft  307  is rotatably arranged in the housing  302 . Each one of two facing inner surfaces of the housing  302  is defined with a groove configured for the mounting shaft  307  to be inserted and mounted. The mounting shaft  307  can rotate around its axis in the groove. The turnplate  308  is installed on the mounting shaft  307  to rotate with the mounting shaft  307 , and located between the two facing inner surfaces of the housing  302 . Since the reversing member  304  is a rotating structure, the gas holes  303  are arranged on the surface of the housing  302  at intervals and around the axis of the mounting shaft  307 , and located on the moving path of the channel  305 , when the turnplate  308  rotates a preset angle, the gas holes  303  are communicated with the channel  305  of the turnplate  308 . 
     In some embodiments, referring to  FIG.  18    and  FIG.  19   , the at least two channels  305  are spaced apart on the turnplate  308  and arranged along the circumference of the turnplate  308 , and the reversing valve  301  further includes: 
     a sealing member  309 , the sealing member  309  is embedded in the turnplate  308  and located at the periphery of the opening of the channel  305  to seal the channel  305 . 
     Since the reversing member  304  is a rotating structure, the channels  305  are arranged along the circumference of the turnplate  308  at intervals, when the turnplate  308  rotates by a preset angle, one of the channels  305  reaches the position corresponding to a certain gas hole  303  and connects with the gas hole  303 , thus realizing communication between the channel  305  and the gas hole  303 . The channel  305  may be an arc-shaped channel, a fan-shaped channel, or other shaped channel, which may be selected according to actual need. In addition, the sealing member  309  is embedded in the turnplate  308  and is located at the periphery of the opening of the channel  305 , such that the sealing member  309  can resist against the inner surface of the housing  302  to sealing the channel  305 . When the turnplate  308  rotates to change the position of the channel  305 , the sealing member  309  moves correspondingly, and when the opening of the channel  305  reaches the position corresponding to the gas hole  303  to communicate with the gas hole  303 , the sealing member  309  automatically provides a sealing between the channel  305  and the gas hole  303 , thereby ensuring the gas tightness. Preferably, the sealing element  309  is a sealing ring. 
     Of course, in other embodiments, the sealing member  309  can also be arranged on the inner surface of the housing  302  to maintain resisting against the surface of the turnplate  308 , which can be selected according to actual situation. 
     In some embodiments, referring to  FIG.  19   , the reversing valve  301  further includes: 
     an elastic ring  310  sleeved on the mounting shaft  307  and sandwiched between the surface of the turnplate  308  away from the sealing member  309  and the surface of the housing  302 . 
     The elastic ring  310  elastically resists against the surface of the turnplate  308  away from the sealing member  309  and the surface of the housing  302  respectively, on the one hand, it can absorb the assembly tolerance of the housing  302  to ensure a smooth rotation of the turnplate  308 , on the other hand, an elastic force can be applied to the sealing member  309  indirectly through the turnplate  308 , such that the sealing member  309  is always bearing a certain degree of pressure, which further improves the gas tightness. 
     In some embodiments, referring to  FIGS.  19  to  21   , the reversing member  304  further includes a trigger protrusion  311  and a detecting member, one of the trigger protrusion  311  and the detecting member is arranged on the turnplate  308 , and the other is arranged on the housing  302 ; 
     wherein, after the turnplate  308  is rotated by a preset angle, the trigger protrusion  311  triggers the detecting member, causing the detecting member to send an electrical signal. 
     When the turnplate  308  rotates relative to the housing  302 , the trigger protrusion  311  cooperates with the detecting member to determine the rotation angle and rotating positions of the turnplate  308 . A control circuit board  312  may be provided, and the detecting member is electrically connected to the control circuit board  312 . As such, after the turnplate  308  is rotated by a preset angle and causes the channel  305  of the turnplate  308  switching to communicate with different gas holes  303 , the detecting member is triggered by the trigger protrusion  311 , and the control circuit board  312  receives the electrical signal of the detecting member to control the driving member  306  to stop the rotation of the turnplate  308 , realizing a gas circuit switching. The trigger protrusion  311  is arranged on the turnplate  308 , and the detecting member is arranged on the housing  302 ; or the detecting member is arranged on the turnplate  308 , and the trigger protrusion  311  is arranged on the housing  302 , which may be selected according to actual need. 
     In some embodiments, referring to  FIGS.  19  to  21   , the trigger protrusion  311  is arranged on the surface of the turnplate  308  opposite to the sealing member  309 ; 
     a surface of the housing  302  is defined with an opening  313 , and the detecting member is inserted through the opening  313  and extends towards the surface of the turnplate  308 . 
     The trigger protrusion  311  is integrally formed with the turnplate  308 , or is detachably connected to the turnplate  308 . The opening  313  is defined on the surface of the housing  302  facing the surface of the turnplate  308  where the trigger protrusion  311  locates, and the detecting member is inserted in the housing  302  through the opening  313  and extends towards the surface of the turnplate  308 . Preferably, the control circuit board  312  is arranged on the outer surface of the housing  302  for electrically connecting with the detecting member. The trigger protrusion  311  rotates with the turnplate  308 , after the turnplate  308  rotates by a preset angle, the trigger protrusion  311  on the turnplate  308  triggers the detecting member on the housing  302 , causing the detecting member to send an electrical signal. 
     In some embodiments, the detecting member includes a photoelectric switch  314  arranged on the rotation path of the trigger protrusion  311 , the trigger protrusion  311  rotates along with the turnplate  308  to leave or enter detecting area of the photoelectric switch  314 ; or, 
     the detecting member includes two mechanical buttons  315 . The two mechanical buttons  315  are arranged in opposite directions of the rotation path of the trigger protrusion  311 . The trigger protrusion  311  rotates along with the turnplate  308  in different directions to respectively contact and press one of the two mechanical buttons  315 . 
     It can select the non-contact photoelectric switch  314  or the contact mechanical button  315  as the detecting member according to an actual need. 
     Referring to  FIGS.  19  and  20   , in case the photoelectric switch  314  is selected as the detecting member, the triggering protrusion  311  is located in the detecting region of the photoelectric switch  314 , when the triggering protrusion  311  rotates along with the turnplate  308  and reaches a preset position, the triggering protrusion  311  leaves the detecting region of the photoelectric switch  314 , such that the photoelectric switch  314  is triggered to send an electrical signal. 
     Referring to  FIG.  21   , in case the mechanical buttons  315  are selected as the detecting member, the two mechanical buttons  315  are arranged in opposite directions of the rotation path of the trigger protrusion  311 , and the trigger protrusion  311  rotates within the region between the two mechanical buttons  315 . When the trigger protrusion  311  rotates along with the turnplate  308  forward and reaches a forward preset position, the trigger protrusion  311  contacts and presses the mechanical button  315  located in the forward direction, thereby triggering the mechanical button  315  to send a detection signal; when the trigger protrusion  311  rotates along with the turnplate  308  backward and reaches a backward preset position, the trigger protrusion  311  contacts and presses the mechanical button  315  located in the backward direction, thereby triggering the mechanical button  315  to send an electric signal. 
     Of course, in other embodiments, the detecting member can also be a sensor, such as a Hall switch. 
     In some embodiments, referring to  FIGS.  18  and  22   , the reversing valve  301  further includes: 
     a transmitting assembly  316 . The driving member  306  includes a motor which is connected with the turnplate  308  through the transmitting assembly  316 . 
     The motor is selected as the driving member  306  to transmit power to the turnplate  308  through the transmitting assembly  316 . The transmitting assembly  316  may be a one-stage transmitting assembly or a multi-stage transmitting assembly, which may be determined according to actual conditions. 
     In some embodiments, the transmitting assembly  316  includes a worm  317 , the turnplate  308  is a worm gear, and the worm  317  engages with the turnplate  308 . 
     The worm  317  is arranged on an output shaft of the motor. During the motor works, the worm  317  rotates along with the output shaft to engage with the turnplate  308  to drive the turnplate  308  to rotate. 
     In some other embodiments, as shown in  FIG.  22   , the transmitting assembly  316  includes a worm  317 , a worm gear  318 , and a transmission gear  319  coaxially connected with the worm gear  308 . The turnplate  308  is defined with gears, the worm  317  is meshed with the worm gear  318 , and the transmission gear  319  is engaged with the turnplate  308 . The worm  317  is arranged on an output shaft of the motor, during the motor works, the worm  317  rotates along with the output shaft of the motor to drive the worm gear  318  to rotate; the transmission gear  319  then rotates with the worm gear  318  to drive the turnplate  308  to rotate. 
     In some embodiments, the at least four gas holes  303  are all located on a same side of the housing  302 ; or, 
     the at least four gas holes  303  are located on opposite two sides of the housing  302 . 
     The gas holes  303  can be arranged as any one of the way described above according to actual situation. As shown in  FIG.  17   , there are four gas holes  303  which are all arranged on a same side of the housing  302 , such an arrangement may facilitate other components (such as detecting members, control circuit boards, etc. ) to be arranged on an opposite side of the housing  302 , and the channel  305  of the turnplate  308  and components inside the housing  302  can be simplified, which is beneficial to avoid a complex structure. As shown in  FIG.  23    and  FIG.  24   , there are four gas holes  303 , one of the four gas holes  303  is arranged on one side of the housing  302 , and the other three gas holes  303  are located on an opposite side of the housing  302 , that is, the gas holes  303  are “3+1” layout. Alternatively, two of the four gas holes  303  may be located on one side of the housing  302 , and the other two gas holes  303  may be located on an opposite side of the housing  302 , that is, the gas holes  303  are “2+2” layout. 
     The present application also provides a base station, including a base station body and the reversing valve  301  described in the foregoing embodiments. The base station body is provided with a water tank  320  and a pump  321 , and the water tank  320  has a vent port  322  and a water guiding port  323 ; 
     the reversing member  304  has a first channel and a second channel. The housing  302  has a first gas hole  303 A communicated with an output end of the pump body  321 , a second gas hole  303 B communicated with an input end of the pump body  321 , a third gas hole  303 C communicated with the vent port, and a fourth gas hole  303 D communicated to the atmospheric environment; 
     wherein, in case the first channel, the first gas hole  303 A, and the fourth gas hole  303 D are communicated, and the second channel, the second gas hole  303 B, and the third gas hole  303 C are communicated, a negative pressure will be formed inside the water tank  320 , such that water can be stored in the water tank  320  through the water guiding port  323 ; 
     in case the first channel, the first gas hole  303 A, and the third gas hole  303 C are communicated, and the second channel, the second gas hole  303 B, and the fourth gas hole  303 D are communicated, a positive pressure will be formed inside the water tank  320 , such that water can be discharged from the water tank  320  through the water guiding port  323 . 
     The structure of the reversing valve  301  has been described in the above-mentioned embodiments. Since the base station of the cleaning system includes all the technical solutions of the above-mentioned embodiments, it has at least all the technical effects brought by the technical solutions of the above-mentioned embodiments, which is not repeated here. 
     In some embodiments, the first gas hole  303 A of the reversing valve  301  is connected with a positive pressure gas inlet pipe, and the positive pressure gas inlet pipe is communicated with the output end of the pump  321 ; the second gas hole  303 B is connected with a negative pressure suction pipe, and the negative pressure suction pipe is communicated with the input end of the pump  321 ; the third gas hole  303 C is connected with a vent pipe, and the vent pipe is communicated with the vent port  322  of the water tank  320 ; the fourth gas hole  303 D is connected with an exhaust pipe, and the exhaust pipe is communicated to the atmospheric environment. 
     The gas circuit can be switched by the control of the reversing valve  301 . Referring to  FIG.  25   , in case the first channel, the first gas hole  303 A, and the fourth gas hole  303 D are communicated (that is, the positive pressure gas inlet pipe is communicated with the exhaust pipe), and the second channel, the second gas hole  303 B, and the third gas hole  303 C are communicated (namely, the negative pressure suction pipe is communicated with the vent pipe), gas in the water tank  320  will enter the negative pressure suction pipe through the vent pipe and the reversing valve  301  successively, then enter the positive pressure gas inlet pipe through the pump  321 , and then enter the atmospheric environment through the reversing valve  301  and the exhaust pipe successively; simultaneously, a negative pressure is generated inside the water tank  320 , so that water can be inputted to the water tank  320  through the water guiding port  323 . The arrow direction indicates the direction of gas flow. 
     Referring to  FIG.  26   , when the first channel, the first gas hole  303 A, and the third gas hole  303 C are communicated (that is, the positive pressure gas inlet pipe is in communication with the vent pipe), and the second channel, the second gas hole  303 B, and the fourth gas hole  303 D are communicated (that is, the negative pressure suction pipe is communicated with the exhaust pipe), gas in the atmospheric environment will enter the negative pressure suction pipe through the exhaust pipe and the reversing valve  301  successively, then enter the positive pressure gas inlet pipe through the pump  321 , and then enter the water tank through the reversing valve  301  and the vent pipe successively; at the same time, a positive pressure is generated inside the water tank  320 , so that water can be discharged from the water tank  320  through the water guiding port  323 . The arrow direction indicates the direction of gas flow. 
     The present application also provides a cleaning system, which includes the base station and the cleaning apparatus described in the foregoing embodiments. The structure of the base station has been described in the foregoing embodiments, since the cleaning system includes all the technical solutions of the foregoing embodiments, it has at least the above-mentioned technical effects brought by the technical solutions of the embodiments, which is not repeated here. 
     Without conflicting with each other, those skilled in the art can combine the different embodiments or examples described in the specification, or combine the features of the different embodiments or examples. 
     What has been disclosed above is only a preferred embodiment of the present disclosure, which is to facilitate the understanding and implementation by those skilled in the art rather than to limit the scope of the present disclosure. Therefore, any equivalent changes made based on the disclosure still fall within the scope of the disclosure.