Water-gas separation structure of range hood
By incorporating a water storage box and partition in the range hood to separate water and air, the problems of odor backflow from the drain pipe and low reliability of electronic components are solved, thereby improving reliability and cleaning effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG CHUNCHEN MASCH CO LTD
- Filing Date
- 2025-05-10
- Publication Date
- 2026-05-12
AI Technical Summary
During the cleaning process of existing range hoods, odors from the drain pipe can easily flow back into the room, and electronic components have low reliability and lifespan in high-temperature and oily environments.
Design a water-gas separation structure for a range hood. By setting a water storage box and a baffle at the bottom of the exhaust pipe, a water seal is formed to prevent odor backflow and discharge wastewater through the exhaust pipe, reducing reliance on electronic components.
It effectively prevents odors from flowing back into the room, improves the reliability and lifespan of the range hood, reduces the failure rate of electronic components, and enhances the cleaning effect.
Smart Images
Figure CN224230098U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of range hood technology and relates to a water-gas separation structure for a range hood. Background Technology
[0002] A range hood is a household appliance used in kitchens to remove cooking fumes. Over time, range hoods have evolved from the initial top-mounted type to side-mounted types. They have become more than just a simple tool for removing kitchen fumes; they now offer various entertainment and functional benefits. However, with prolonged use, a large amount of grease accumulates on the ductwork and fan impeller, affecting fume extraction efficiency. Therefore, range hoods require regular cleaning, leading to the emergence of self-cleaning range hoods that require no disassembly.
[0003] As disclosed in the patent document (application number: 202210463061.6), the cooking device and its control method include a cleaning device for cleaning the impeller and filter of the fan system. The cleaning device includes a cleaning medium supply pipe and a nozzle. The cleaning medium supply pipe extends in a left-right direction, and the nozzle is set on the cleaning medium supply pipe. The cleaning device is designed as an external tap water pipeline. Tap water is connected to one end of the inlet solenoid valve through the inlet pipe. The other end of the inlet solenoid valve is connected to the first heating module. The outlet of the heating module is directly or indirectly connected to the cleaning solenoid valve. The cleaning solenoid valve is connected to each cleaning medium supply pipe through a hose. A normally open solenoid valve is installed at the bottom of the fan box. An oil leakage hole is opened at the lowest position of the volute. The normally open solenoid valve corresponds to the position of the oil leakage hole and can open or close the oil leakage hole. When cleaning the range hood, tap water is sprayed out from the nozzle on the supply pipe. The cleaning liquid flows into the lower volute to soak the impeller. When drainage is required after soaking, the oil leakage hole is opened through the solenoid valve at the bottom to drain the water.
[0004] Since kitchens typically only have a drain pipe connected to the sink, this grease leak hole is connected to the drain pipe for drainage. The internal environment of a range hood is quite harsh, especially the bottom of the casing where stubborn grease adheres. The temperature is also high during exhaust, all of which reduce the reliability and lifespan of electronic components such as solenoid valves. Even spring-loaded check valves can fail due to grease buildup. However, if no on / off control is installed at this location, odors from the drain pipe will backflow into the range hood and into the room when the range hood is not in operation. Summary of the Invention
[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a water-gas separation structure for range hoods. This water-gas separation structure can ensure reliable operation while preventing odors from flowing back into the room.
[0006] The objective of this utility model can be achieved through the following technical solution: a water-gas separation structure for a range hood, the range hood including a flue shell with an oil fume inlet and an exhaust pipe connected to the flue shell, characterized in that the bottom of the flue shell is also connected to the exhaust pipe through a drain pipe, the water-gas separation structure including a drain outlet at the bottom of the exhaust pipe facing downwards, the bottom of the exhaust pipe also having a water storage box, the drain outlet being in relative communication with the inner cavity of the lower water storage box, a drain interface higher than the inner bottom surface being provided on the side wall of the water storage box, and a partition extending downwards into the water storage box on the exhaust pipe, the partition separating the drain outlets on both sides from the drain interface, the lower edge of the partition being lower than the drain interface, and a water passage gap being formed between the lower edge of the partition and the inner bottom surface of the water storage box.
[0007] The exhaust port of this application is connected to a water storage box, and the drain interface on the side wall of the water storage box can be connected to the kitchen's drain pipe. During use, the flue shell draws in fumes through the fume inlet, and the fumes are discharged outdoors through the exhaust pipe. Wastewater generated during range hood cleaning is discharged into the exhaust pipe from the drain pipe at the bottom of the flue shell. The wastewater in the exhaust pipe enters the water storage box through the exhaust port and then flows into the drain pipe through the drain interface. Because this application discharges wastewater from the flue shell into the exhaust pipe and then into the drain pipe, even if the drain pipe is blocked and backflow occurs, the wastewater in the drain pipe will only flow back into the exhaust pipe. The wastewater in the exhaust pipe can be discharged from its own exhaust port and will not flow back into the flue shell. Therefore, this structure does not require the installation of electronic components such as solenoid valves to control the flow of the drain pipe at the bottom of the flue shell. This avoids the high failure rate caused by installing electronic components in the harsh environment of the flue shell, which is characterized by high temperature and heavy grease, thus ensuring the reliability and lifespan of the range hood. Furthermore, a water storage box is connected to the exhaust pipe, and a partition separates the drain outlet from the drain interface. Therefore, after the sewage in the exhaust pipe falls into the water storage box from the drain outlet, it needs to pass through the water gap between the lower edge of the partition and the inner side of the water storage box. When the water level is higher than the lower edge of the drain interface, the sewage in the water storage box is discharged into the drain pipe from the drain interface. After the range hood is cleaned, a portion of the water will remain in the water storage box, and its liquid level is at the lower edge of the drain interface. However, the lower edge of the partition is lower than the drain interface, so the lower part of the partition is inserted into the sewage. That is, the sewage blocks the water gap, forming a water seal. Therefore, without the need for electronic components such as solenoid valves to ensure reliability, it can prevent the smoke from entering the drain pipe when the range hood is being drawn, and it can also prevent the odor in the drain pipe from flowing back into the flue shell and entering the room.
[0008] In the aforementioned water-gas separation structure of the range hood, the lowest point of the drain port's edge is lower than the edge of the drain outlet, and the lower edge of the partition is also lower than the lowest point of the drain port's edge. The lower position of the drain port's edge ensures that wastewater in the exhaust pipe can be completely drained into the water storage box, preventing wastewater residue in the exhaust pipe. The lower edge of the partition, being lower than the lowest point of the drain port's edge, ensures that after cleaning, the lower edge of the partition can be inserted into the wastewater, thus forming a water seal and preventing odors from the drain pipe from flowing back into the flue shell and entering the room.
[0009] In the aforementioned water-gas separation structure of the range hood, the exhaust pipe includes a horizontally laid long pipe and a water-gas separation pipe. One end of the long pipe is connected to the flue shell, and the water-gas separation pipe is sleeved on the other end of the long pipe. The water-gas separation pipe is a circular pipe, and the drain outlet is located at the bottom of the water-gas separation pipe. The water storage box is fixed to the lower side of the bottom of the water-gas separation pipe. The horizontal laying of the long pipe allows wastewater to flow along it and be discharged from the exhaust outlet. Simultaneously, the wastewater flushed from the flue shell contains detergent components. Therefore, by flowing the wastewater along the long pipe, the detergent-containing wastewater can decompose and clean the grease inside the long pipe, improving the fume extraction effect. The water storage box and drain outlet are both located on independent water-gas separation pipes, facilitating manufacturing. Furthermore, the water-gas separation pipe can be installed on existing range hood exhaust pipes, facilitating the modification of existing fume extraction systems. The independent water-gas separation pipe also facilitates future maintenance and replacement.
[0010] In the aforementioned water-gas separation structure of the range hood, a filter screen plate covering the drain outlet is also installed inside the water-gas separation pipe. This filter screen plate has filter holes. A partition plate is vertically fixed to the lower side of the filter screen plate, extending downwards through the drain outlet. The partition plate is close to the edge of the drain outlet and separates the filter holes on both sides from the drain interface. The filter screen plate covers the drain outlet, filtering the wastewater in the drain storage box and preventing clumps of grease from entering the drain pipe and causing blockages. Fixing the partition plate to the lower side of the filter screen plate allows the water-gas separation pipe to be inserted after the filter screen plate is fixed, facilitating processing and assembly.
[0011] In the aforementioned water-gas separation structure of the range hood, the partition is flat, with its surface facing the drain interface. The two ends of the partition abut against the two inner walls of the water storage box. The filter holes and drain interface are located on opposite sides of the partition. Because the two ends of the partition abut against the inner walls of the water storage box, the partition divides the inner cavity of the water storage box into two chambers. These two chambers are connected only by a water-passing gap between the lower edge of the partition and the bottom surface of the water storage box. When the water-passing gap is blocked by retained sewage, the two chambers on either side of the partition are separated, i.e., the filter holes and drain interface are isolated, preventing odors from the drain pipe from flowing back into the flue shell and entering the room.
[0012] In the aforementioned water-gas separation structure of the range hood, the baffle is cylindrical and circumferentially arranged along the edge of the drain outlet. The filter holes are located on the inner side of the baffle, and the drain interface is located on the outer side of the baffle. The cylindrical baffle only requires the filter holes to be located on the inner side, without strict requirements on the baffle's position. This allows wastewater in the exhaust pipe to fall only from the inner side of the baffle, then flow through the water gap to the outer side of the baffle, and finally be discharged into the drain pipe through the drain interface. When the water gap is blocked by wastewater, the inner and outer sides of the baffle are separated into two chambers.
[0013] In the aforementioned water-gas separation structure of the range hood, the filter screen is arc-shaped, and the lower side of the outer edge of the filter screen abuts against the inner bottom surface of the water-gas separation pipe. A pull ring is also provided on the filter screen. The arc-shaped filter screen fits more closely to the inner bottom surface of the cylindrical water-gas separation pipe, and the pull ring facilitates the disassembly, assembly, and maintenance of the filter screen.
[0014] In the aforementioned water-gas separation structure of the range hood, an inspection port is provided at the upper part of the water-gas separation pipe. This inspection port is located above the drain outlet and is connected to a plug. The inspection port is opposite to the filter screen, and the pull ring design facilitates the cleaning and maintenance of the filter screen.
[0015] In the aforementioned water-gas separation structure of the range hood, the water storage box includes a box body and a bottom cover, both fixed to the lower side of the water-gas separation pipe and open at the bottom. The bottom cover is fixedly sealed to the bottom of the box body, and a water passage gap is formed between the lower edge of the aforementioned partition and the upper side of the bottom cover. The box body is cylindrical, with its upper edge welded and fixed to the lower side of the water-gas separation pipe. The bottom cover is fastened to the lower edge of the box body and fixed by welding or snap-fitting, facilitating future maintenance and replacement.
[0016] In the aforementioned water-gas separation structure of the range hood, the water storage box has a tubular protruding connecting pipe at the drain interface. A T-connector is fitted onto the connecting pipe, with one end of the T-connector facing upwards and fitted with a float-type level gauge extending downwards into the T-connector. The float-type level gauge is an existing liquid level detection component. Its detection end extends downwards into the T-connector. When the drain pipe becomes blocked, preventing sewage from draining from the T-connector and causing the liquid level to rise, the float-type level gauge can detect the liquid level and provide an alarm signal when it reaches the warning line, improving safety and reliability.
[0017] Compared with existing technologies, the water-gas separation structure of this range hood has the following advantages:
[0018] 1. A water storage box is also connected to the exhaust pipe. The partition separates the drain outlet from the drain interface. Therefore, after the range hood is cleaned, a portion of water will remain in the storage box. The liquid level is at the lower edge of the drain interface. The lower part of the partition is inserted into the sewage, which seals the water passage gap and forms a water seal. This can prevent the smoke from entering the drain pipe when the range hood is being drawn, and also prevent the odor in the drain pipe from flowing back into the flue shell and entering the room.
[0019] 2. Since this application discharges the wastewater from the flue shell into the exhaust pipe, and then from the exhaust pipe into the sewage pipe, even if the sewage pipe is blocked and backflow occurs, the wastewater in the sewage pipe will flow back into the exhaust pipe. The wastewater in the exhaust pipe can be discharged from its own exhaust port and will not flow back into the flue shell. Therefore, this structure does not require the installation of electronic components such as solenoid valves to control the opening and closing of the drain pipe at the bottom of the flue shell. This avoids the high failure rate caused by installing electronic components in the harsh environment of the flue shell, which is characterized by high temperature and heavy oil, and thus ensures the reliability and service life of the range hood.
[0020] 3. Since the wastewater flushed from inside the flue shell contains detergent, the wastewater is first discharged into the exhaust pipe and then flows into the drain outlet along the exhaust pipe. The wastewater containing detergent can also decompose and clean the oil stains in the exhaust pipe, thereby cleaning the exhaust pipe and further improving the oil fume extraction effect. Attached Figure Description
[0021] Figure 1 This is a structural diagram of a range hood.
[0022] Figure 2 This is a three-dimensional structural diagram of the flue shell.
[0023] Figure 3 This is a three-dimensional structural diagram of the flue shell from another perspective.
[0024] Figure 4 This is a cross-sectional view of the flue shell.
[0025] Figure 5 yes Figure 1 A partial structural cross-sectional view at point AA.
[0026] Figure 6 This is a three-dimensional structural diagram of the water-air separator pipe without a filter screen installed.
[0027] Figure 7 This is a three-dimensional structural diagram of a water-air separator.
[0028] Figure 8 yes Figure 5 A partial structural cross-sectional view of BB.
[0029] In the diagram, 1. Flue shell; 11. Fume inlet; 12. Exhaust vent; 13. Drain outlet; 2. Fan; 21. Casing; 211. Air inlet; 212. Air outlet; 22. Impeller; 23. Motor; 3. Exhaust pipe; 31. Long pipe body; 311. Drain inlet; 32. Water-air separator pipe; 321. Sewage outlet; 322. Inspection port; 323. Plug; 4. Water storage box; 41. Box body; 411. Drain interface; 412. Connecting pipe; 413. Water passage gap; 42. Bottom cover; 5. Filter screen; 51. Filter hole; 52. Partition; 53. Pull ring; 6. T-connector; 61. Float-type level gauge; 7. Foam synthesizer; 71. Spray box; 72. Spray head; 8. Drain pipe; 9. Electric push rod; 91. Lifting door. Detailed Implementation
[0030] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0031] Example 1:
[0032] like Figures 1 to 4As shown, a water-gas separation structure for a range hood is disclosed. The range hood includes a flue shell 1, a fan 2, and an exhaust pipe 3. The flue shell 1 is flat, with a rectangular upper part and an inverted triangular lower part. A long strip-shaped fume inlet 11 is provided on the upper side wall of the flue shell 1 along its width direction, and an exhaust vent 12 is provided on the lower side wall of the flue shell 1, which is higher than the bottom surface of the flue shell 1. An electric push rod 9 is vertically fixed on the inner side wall of the flue shell 1. The drive end of the electric push rod 9 is vertically upward and fixed with a lifting plate. When the electric push rod 9 pushes the lifting door 91 upward, the lifting door 91 can cover the fume inlet 11. The fan 2 includes a housing 21, an impeller 22 disposed inside the housing 21, and a motor 23 that drives the impeller 22 to rotate. The air inlet 211 of the housing 21 is opened on the side wall, and the air outlet 212 is opened on the bottom surface. The housing 21 is fixed to the side of the flue shell 1, and the air inlet 211 of the housing 21 is connected to the exhaust port 12 of the flue shell 1. The exhaust pipe 3 is horizontally arranged, and the inlet end of the exhaust pipe 3 is bent upward and connected to the air outlet 212 of the housing 21. A spray box 71 is installed at the top inside the flue shell 1. The spray box 71 has spray holes. A spray head 72 is installed inside the casing 21 of the fan 2. Both the spray box 71 and the spray head 72 are connected to the external foam synthesizer 7. That is, the foam synthesized by the foam synthesizer 7 is sprayed through the spray holes of the spray box 71 onto the inner wall of the flue shell 1 and gradually fills the entire inner cavity of the flue shell 1. The spray head 72 sprays foam toward the impeller 22 and gradually fills the entire casing 21. The bottom of the flue shell 1 is connected to the exhaust pipe 3 through a drain pipe 8. Specifically, a liquid outlet 13 is provided at the lowest position of the bottom surface of the flue shell 1, and a liquid inlet 311 is provided on the side wall of the exhaust pipe 3. The liquid inlet 311 is close to the inlet end of the exhaust pipe 3, and the liquid outlet 13 is higher than the liquid inlet 311. The drain pipe 8 is U-shaped, with one end pointing vertically upward and connected to the drain outlet 13, and the other end pointing vertically upward and bent laterally to connect to the drain inlet 311. The U-shaped drain pipe 8 can retain some water after cleaning, thereby sealing the drain pipe 8 to form a water seal when the oil fume is extracted, preventing the smoke in the exhaust pipe 3 from flowing back to the flue shell 1 and affecting the oil fume extraction efficiency.
[0033] Specifically, combined Figures 5 to 8As shown, the exhaust pipe 3 includes a horizontally arranged long pipe body 31 and a water-air separation pipe 32. One end of the long pipe body 31 is connected to the air outlet 212 of the casing 21. The water-air separation pipe 32 is sleeved on the other end of the long pipe body 31. The water-air separation pipe 32 is a round pipe and the long pipe body 31 is a square pipe. Therefore, the water-air separation pipe 32 can be sleeved after the end of the long pipe body 31 is narrowed. The water-air separation structure includes a drain outlet 321 set at the bottom of the water-air separation pipe 32 and facing downward. There is also a water storage box 4 at the bottom of the water-air separation pipe 32. The drain outlet 321 is connected to the inner cavity of the water storage box 4 below. A drain interface 411 is opened on the side wall of the water storage box 4. The drain interface 411 is higher than the inner bottom surface of the water storage box 4 and is used to connect the drain pipe. The lowest position of the opening edge of the drain interface 411 is lower than the opening edge of the drain outlet 321. A filter screen 5 is also laid inside the water-air separation pipe 32. The filter screen 5 has filter holes 51. The filter screen 5 is arc-shaped, and the lower side of the outer edge of the filter screen 5 is attached to the inner bottom surface of the water-air separation pipe 32. A partition 52 is vertically fixed to the lower side of the filter screen 5. The partition 52 is cylindrical and extends vertically downward through the drain outlet 321 and into the water storage box 4. The partition 52 is arranged circumferentially along the edge of the drain outlet 321, that is, the partition 52 is close to the edge of the drain outlet 321, so that the partition 52 separates the drain outlet 321 from the drain interface 411. The lower edge of the partition 52 is lower than the drain interface 411, that is, the lower edge of the partition 52 is lower than the lowest position of the opening edge of the drain interface 411. There is a water passage gap 413 between the lower edge of the partition 52 and the inner bottom surface of the water storage box 4. The filter holes 51 are all located on the inner side of the partition 52, and the drain interface 411 is located on the outer side of the partition 52. Therefore, when sewage is stored in the water storage box 4, the lower edge of the partition 52 is inserted into the sewage to form a water seal, thereby isolating the filter holes 51 from the drain interface 411.
[0034] The water-air separator pipe 32 has an inspection port 322 at its upper part, located above the drain outlet 321. A plug 323 is connected to the inspection port 322. A pull ring 53 is also provided on the filter screen 5 for easy cleaning and maintenance. The water storage box 4 includes a box body 41 and a bottom cover 42. The box body 41 is cylindrical, with its upper edge welded to the lower side of the water-air separator pipe 32. The bottom cover 42 is fastened to the lower edge of the box body 41 and welded to it. The water-air separator pipe 32 has a tubular protruding connecting part 412 at the drain interface 411. A three-way pipe 6 is fitted onto the connecting part 412, with one end of the three-way pipe 6 facing upwards and fitted with a float-type level gauge 61 extending downwards into the three-way pipe 6.
[0035] Example 2:
[0036] The structure of the quick connector is basically the same as that of Embodiment 1. The difference is that the partition 52 is flat, and the plate surface of the partition 52 faces the drain interface 411. The two ends of the partition 52 abut against the two inner side walls of the water storage box 4 respectively. The filter hole 51 and the drain interface 411 are located on both sides of the partition 52 respectively.
[0037] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.
[0038] Although this document frequently uses terms such as flue shell 1, fume inlet 11, and exhaust vent 12, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any additional limitation would contradict the spirit of this utility model.
Claims
1. A water-gas separation structure for a range hood, the range hood comprising a flue shell (1) with a fume inlet (11) and an exhaust pipe (3) connected to the flue shell (1), characterized in that, The bottom of the flue shell (1) is also connected to the flue pipe (3) through the drain pipe (8). The water-air separation structure includes a drain outlet (321) opened at the bottom of the flue pipe (3) and facing downward. The bottom of the flue pipe (3) also has a water storage box (4). The drain outlet (321) is connected to the inner cavity of the water storage box (4) below. A drain interface (411) higher than the inner bottom surface is opened on the side wall of the water storage box (4). The flue pipe (3) is also provided with a partition (52) extending downward into the water storage box (4). The partition (52) separates the drain outlet (321) on both sides from the drain interface (411). The lower edge of the partition (52) is lower than the drain interface (411), and there is a water passage gap (413) between the lower edge of the partition (52) and the inner bottom surface of the water storage box (4).
2. The water-gas separation structure of the range hood according to claim 1, characterized in that, The lowest position of the opening edge of the drain interface (411) is lower than the opening edge of the sewage outlet (321), and the lower edge of the partition (52) is lower than the lowest position of the opening edge of the drain interface (411).
3. The water-gas separation structure of the range hood according to claim 2, characterized in that, The exhaust pipe (3) includes a horizontally laid long pipe body (31) and a water-gas separation pipe (32). One end of the long pipe body (31) is connected to the flue shell (1), and the water-gas separation pipe (32) is sleeved on the other end of the long pipe body (31). The water-gas separation pipe (32) is a round pipe. The above-mentioned sewage outlet (321) is opened at the bottom of the water-gas separation pipe (32), and the water storage box (4) is fixed to the bottom lower side of the water-gas separation pipe (32).
4. The water-gas separation structure of the range hood according to claim 3, characterized in that, The water-air separation pipe (32) is also equipped with a filter screen plate (5) that covers the drain outlet (321). The filter screen plate (5) has filter holes (51). The partition plate (52) is vertically fixed on the lower side of the filter screen plate (5) and extends downward through the drain outlet (321). The partition plate (52) is close to the edge of the drain outlet (321) and separates the filter holes (51) on both sides from the drain interface (411).
5. The water-gas separation structure of the range hood according to claim 4, characterized in that, The partition (52) is flat, and the surface of the partition (52) faces the drain port (411). The two ends of the partition (52) abut against the two inner side walls of the water storage box (4). The filter hole (51) and the drain port (411) are located on both sides of the partition (52).
6. The water-gas separation structure of the range hood according to claim 4, characterized in that, The partition (52) is cylindrical and is arranged circumferentially along the edge of the drain port (321). The filter hole (51) is located on the inner side of the partition (52), and the drain interface (411) is located on the outer side of the partition (52).
7. The water-gas separation structure of the range hood according to claim 4, 5, or 6, characterized in that, The filter screen (5) is arc-shaped, and the lower side of the outer edge of the filter screen (5) is attached to the inner bottom surface of the water-air separation pipe (32). A pull ring (53) is also provided on the filter screen (5).
8. The water-gas separation structure of the range hood according to claim 7, characterized in that, The water-air separation pipe (32) is also provided with an inspection port (322) at the top. The inspection port (322) is located above the sewage outlet (321), and a plug (323) is connected to the inspection port (322).
9. The water-gas separation structure of the range hood according to claim 3, 4, 5, or 6, characterized in that, The water storage box (4) includes a box body (41) fixed on the lower side of the water-air separation pipe (32) and an open bottom cover (42). The bottom cover (42) is fixedly sealed on the bottom of the box body (41), and a water passage gap (413) is formed between the lower edge of the partition (52) and the upper side of the bottom cover (42).
10. The water-gas separation structure of the range hood according to any one of claims 1 to 6, characterized in that, The water storage box (4) has a tubular protruding connecting pipe (412) at the drain interface (411), and a three-way pipe (6) is sleeved on the connecting pipe (412). One end of the three-way pipe (6) faces upward and is equipped with a float-type liquid level gauge (61) that extends downward into the three-way pipe (6).