A safe sealed drainage system

Abstract

The present invention discloses a safety sealed drainage system, including a drainage pipe, a manhole is arranged on the drainage pipe, the manhole divides the drainage pipe into an upstream pipe section and a downstream pipe section, the upstream pipe section and the downstream pipe section are respectively connected to the manhole, a manhole cover is buckled on the manhole, a manhole seat ring is fixedly arranged at the manhole mouth, a manhole cover is arranged on the manhole seat ring, an elastic sealing ring is arranged between the manhole cover and the manhole seat ring, a locking mechanism is arranged between the manhole cover and the manhole, and an external unlocking mechanism is arranged between the locking mechanism and the manhole cover. The beneficial effects of the present invention are as follows: when the water level in the manhole is high or the water flow in the drainage pipe impacts, the manhole cover and the manhole remain locked, and water can be prevented from overflowing, and the external unlocking mechanism is arranged to facilitate the installation and opening of the manhole cover.

Description

Technical Field

[0001] The invention belongs to the field of urban drainage system structure, and in particular relates to a safe sealed drainage system. Background Art

[0002] The urban sewer system includes rainwater pipes and sewage pipes, and manholes are set up at intervals on the drainage pipes. The functions of the manhole are: on the one hand, it serves as a sedimentation pool for silt and debris, which is convenient for cleaning and dredging; on the other hand, it serves as an entrance and exit for maintenance and construction personnel. In order to ensure the safety of pedestrians, manhole covers are buckled on the manholes. For sewage pipes, manhole covers also play a role in reducing the escape of sewer odors. However, when the drainage pipe is blocked and the flow cross-section is reduced, the same size of water flows faster in the drainage pipe, and the impact force increases, which may cause the manhole cover to be washed away and displaced; or because of continuous rainfall causing urban waterlogging, the manhole cover may also be washed away. These phenomena pose huge safety hazards, and pedestrian casualties caused by them have also been reported. Therefore, it is very necessary to improve the structural design of manholes and manhole covers. Summary of the invention

[0003] In view of this, the present invention provides a safe sealed drainage system.

[0004] The technical solution is as follows:

[0005] A safe sealed drainage system comprises a drainage pipe, a manhole is arranged on the drainage pipe, the manhole divides the drainage pipe into an upstream pipe section and a downstream pipe section, the upstream pipe section and the downstream pipe section are respectively connected to the manhole, and the manhole is covered with a manhole cover. The key point is that:

[0006] The wellhead of the manhole is fixedly provided with a wellhead seat ring, the wellhead seat ring is provided with a well cover, and an elastic sealing ring is provided between the well cover and the wellhead seat ring;

[0007] A locking mechanism is provided between the manhole cover and the manhole, and an external unlocking mechanism is provided between the locking mechanism and the manhole cover.

[0008] The advantage of the above design is that when the water level in the manhole is high or the water flow in the drain pipe is impacted, the manhole cover and the manhole remain locked and can prevent water from overflowing. An external unlocking mechanism is provided to facilitate the installation and opening of the manhole cover.

[0009] As a preferred technical solution, the locking mechanism comprises a locking rod hole, a locking disk, a locking rod and a tension spring;

[0010] The inner wall of the manhole opening is provided with at least two locking rod holes, and the locking rod holes are evenly distributed on the inner wall of the manhole in an annular direction;

[0011] The locking disk is connected to the middle of the lower surface of the manhole cover, the locking disk is arranged horizontally, the locking rod is connected to the upper surface of the locking disk, the locking rod corresponds to the locking rod hole one by one, the locking rod is arranged radially along the locking disk, the inner end of the locking rod is hinged to the locking disk, and the outer end of the locking rod is inserted into the corresponding locking rod hole;

[0012] The locking plate is suspended below the manhole cover by a tension spring, and the tension spring maintains the locking rod inserted into the locking rod hole.

[0013] The above design has the advantage that after the manhole cover is installed, the outer end of the locking rod is inserted into the corresponding locking ring and locking rod hole under the action of the tension spring to prevent the manhole cover from falling out, thereby achieving automatic locking.

[0014] As an optimal technical solution, a buoyancy block is provided on the lower surface of the above-mentioned lock disk. When the buoyancy block is subjected to upward buoyancy, it pushes the lock disk upward, driving the lock rod to move upward and rotate, so that the length of the extension section of the lock rod in the lock rod hole is increased.

[0015] The advantage of adopting the above design is that when the water level in the manhole is high, the buoyancy of the buoyancy block makes the manhole cover further locked and can withstand the impact of water flow.

[0016] As a preferred technical solution, the above-mentioned external unlocking mechanism includes a guide unlocking hole, which vertically penetrates the middle of the manhole cover, and an unlocking push rod is movably inserted in the guide unlocking hole. The unlocking push rod is fixedly arranged on the upper surface of the lock disk, and the unlocking push rod can freely pass through the tension spring.

[0017] With the above design, the unlocking push rod and the guide unlocking hole cooperate with each other to provide a stable guide for the lifting and lowering of the lock plate to prevent lateral deviation. When unlocking, the operator pushes the unlocking push rod downward on the ground to lower the lock plate and drive the lock rod to move out of the lock rod hole to achieve unlocking.

[0018] As a preferred technical solution, the inner diameter of the guide unlocking hole gradually decreases from its lower end to its upper end, and the shape of the unlocking push rod is adapted to the shape of the guide unlocking hole and does not pass through the upper end of the guide unlocking hole.

[0019] With the above design, when the water level in the manhole is high, the buoyancy block rises, and the locking plate and the unlocking push rod also rise accordingly, fitting more closely with the inner wall of the guide unlocking hole, thereby preventing water from overflowing from the guide unlocking hole.

[0020] As a preferred technical solution, a lock ring is fixedly arranged on the lower surface of the manhole cover, the lock ring is close to the inner wall of the wellhead, the lock ring corresponds to the lock rod hole one by one, and the opening of the lock rod hole is directly connected to the inner hole of the lock ring;

[0021] The locking rod passes through the corresponding locking ring and is inserted into the corresponding locking rod hole.

[0022] With the above design, the lock ring plays a limiting and guiding role in the movement of the lock rod, which facilitates locking and unlocking. The lock ring is close to the lock rod hole, and the lock ring forms a lever fulcrum of the lock rod. The pulling force of the lock disk on the inner end of the lock rod is amplified at the outer end of the lock rod, so that the outer end of the lock rod is stably inserted in the lock rod hole.

[0023] As a preferred technical solution, the locking ring comprises an n-shaped frame, which is fixedly connected to the manhole cover, and an anti-slip rod is connected between the free ends of the two arms of the n-shaped frame, and the anti-slip rod and the n-shaped frame form the locking ring;

[0024] The anti-drop rod is connected to the corresponding locking rod through a limiting link, a strip hole is provided on the locking rod corresponding to the limiting link, one end of the limiting link is connected to a hinge column which is passed through the strip hole, and the other end of the limiting link is hinged to the anti-drop rod.

[0025] The above design is conducive to maintaining the relative position of the locking rod and the locking ring, so that the locking rod can only rotate and move slightly in the vertical plane around the anti-drop rod. When the manhole cover is subjected to an upward thrust, the locking ring also tends to move upward. The restraining effect of the connecting rod on the locking rod can prevent the outer end of the locking rod from falling out.

[0026] As a preferred technical solution, the locking rod hole is a wedge-shaped hole, the end with a larger inner diameter of the locking rod hole is an open end, the top of the inner wall of the locking rod hole is inclined, and the top of the inner wall of the locking rod hole extends obliquely upward to the upper edge of the inner hole close to the locking ring;

[0027] The upper surface of the outer end of the locking rod is a wedge inclined surface matched with the locking rod hole.

[0028] With the above design, after the locking rod enters the locking rod hole, the top of the inner wall of the locking rod hole presses down on the upper surface of the outer end of the locking rod, which is beneficial to maintaining the stability of the outer end of the locking rod after it extends into the locking rod hole, reducing shaking and preventing loosening; in addition, the purpose of the inclined setting of the top of the inner wall of the locking rod hole is that the outer end of the locking rod is inserted into the locking rod hole and continues to move downward, causing the locking rod itself to rotate, and the locked state is more stable.

[0029] As a preferred technical solution, the wellhead seat ring comprises a vertical tube and a horizontal ring, the lower edge of the vertical tube is connected to the outer edge of the horizontal ring to form the wellhead seat ring, the inner side wall of the wellhead seat ring forms a mounting step, the well cover falls on the mounting step, and the well cover is adapted to the inner cavity of the vertical tube;

[0030] The elastic sealing ring is in the shape of a ring sleeve, the outer side of the elastic sealing ring is in contact with the cylindrical inner wall of the installation step, and the inner side of the elastic sealing ring is in contact with the annular side wall of the manhole cover;

[0031] The elastic sealing ring includes a sealing ring body, and the two edges of the lower end surface of the sealing ring body extend downward along the outer side and the inner side of the sealing ring body respectively to form two outer and inner fitting parts, and the area between the two fitting parts forms an anti-backflow cavity.

[0032] With the above design, the sealing ring body plays the main sealing role, and the two fitting parts have a deformation effect. After water enters the anti-backflow cavity, the water pressure causes the fitting parts to expand outward, and the fit with the inner wall of the installation step or the annular side wall of the manhole cover is high, and the sealing performance is good.

[0033] As a preferred technical solution, the inner wall of the vertical tube is inclined at an angle of 5° to 15°.

[0034] With the above design, since the inner diameter of the cylindrical inner wall gradually decreases from top to bottom, when the manhole cover moves downward under the force, the distance between the manhole cover and the inner circumferential surface of the vertical cylinder is reduced, the sealing ring body is compressed, and the fit between the manhole cover and the vertical cylinder is tighter, thereby improving the sealing performance.

[0035] Compared with the prior art, the present invention has the following beneficial effects: when the water level in the manhole is high or the water flow in the drain pipe impacts, the manhole cover and the manhole remain locked and can prevent water from overflowing; an external unlocking mechanism is provided to facilitate the installation and opening of the manhole cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of the present invention;

[0037] Figure 2 It is a top view schematic diagram of the present invention;

[0038] Figure 3 for Figure 2 Middle AA section view;

[0039] Figure 4 for Figure 3 Enlarged view of the middle m1 part;

[0040] Figure 5 for Figure 3 Enlarged view of the middle m2 part;

[0041] Figure 6 A schematic diagram of a locking rod inserted into a locking rod hole, wherein the manhole cover is not shown;

[0042] Figure 7 This is a bottom view of the manhole cover;

[0043] Figure 8 for Figure 7 Enlarged view of the middle m3 part;

[0044] Fig. 9 It is a structural schematic diagram of the wellhead seat ring;

[0045] Fig.10 It is a structural schematic diagram of the sealing ring;

[0046] Fig.11 for Fig.10 Middle BB section view. DETAILED DESCRIPTION

[0047] The present invention is further described below in conjunction with embodiments and drawings.

[0048] like Figures 1 to 4 As shown, a safety sealed drainage system includes a drainage pipe 600, on which a manhole 100 is arranged. The manhole 100 divides the drainage pipe 600 into an upstream pipe section 601 and a downstream pipe section 602, and the upstream pipe section 601 and the downstream pipe section 602 are respectively connected to the manhole 100. A manhole seat ring 200 is fixedly arranged at the wellhead of the manhole 100, on which a manhole cover 300 is arranged, and an elastic sealing ring 400 is arranged between the manhole cover 300 and the wellhead seat ring 200.

[0049] A locking mechanism is provided between the manhole cover 300 and the manhole 100, and the locking mechanism includes a locking rod hole 204, a locking disk 510, a locking rod 520 and a tension spring 560. At least two locking rod holes 204 are provided on the inner wall of the manhole 100, and the locking rod holes 204 are evenly distributed on the inner wall of the manhole 100 in an annular direction. The locking disk 510 is connected to the middle of the lower surface of the manhole cover 300, and the locking disk 510 is arranged horizontally. The locking rod 520 is connected to the upper surface of the locking disk 510, and the locking rod 520 corresponds to the locking rod hole 204 one by one. The locking rod 520 is arranged radially along the locking disk 510, and its inner end is hinged to the locking disk 510, and its outer end is inserted into the corresponding locking rod hole 204. The locking disk 510 is suspended below the manhole cover 300 by the tension spring 560, and the tension spring 560 maintains the locking rod 520 inserted into the locking rod hole 204. In order to facilitate the connection between the tension spring 560 and the manhole cover 300, a guide sleeve is fixedly provided in the middle of the lower surface of the manhole cover 300, and the upper end of the tension spring 560 is sleeved on the outer wall of the guide sleeve.

[0050] The locking mechanism can prevent the manhole cover 300 from shifting due to water flow impact, and cooperate with the elastic sealing ring 400 to prevent water from overflowing when the water level in the manhole is high. It is particularly suitable for drainage systems in key areas, such as Figure 1 In the area shown, since the upstream pipe section 601 is located in a higher terrain area, when the downstream pipe section 601 is blocked or the upstream water volume is large, the existing manhole cover structure is bound to cause water overflow. However, the use of the manhole cover structure of the present invention can effectively prevent this.

[0051] To facilitate installation and opening of the manhole cover, an external unlocking mechanism is provided between the locking mechanism and the manhole cover 300. Figure 5 As shown, the external unlocking mechanism includes a guide unlocking hole 301, which vertically penetrates the middle of the manhole cover 300, and the guide unlocking hole 301 is directly connected to the inner hole of the guide sleeve. An unlocking push rod 550 is movably inserted into the guide unlocking hole 301, and the unlocking push rod 550 is fixedly arranged on the upper surface of the lock plate 510, and the unlocking push rod 550 freely passes through the tension spring 560 and the guide sleeve. The unlocking push rod 550 cooperates with the guide unlocking hole 301, and also plays a stabilizing and guiding role in the lifting and lowering of the lock plate 510 to prevent lateral deviation. When unlocking, the operator pushes the unlocking push rod 550 downward on the ground to make the lock plate 510 descend, thereby driving the lock rod 520 to escape from the lock rod hole 204 outward to achieve unlocking.

[0052] like Figure 3 In order to further enhance the installation stability of the manhole cover 300, a buoyancy block 540 is provided on the lower surface of the lock plate 510. When the buoyancy block 540 is subjected to the upward buoyancy, it pushes the lock plate 510 upward, drives the inner end of the lock rod 520 to move upward and rotate, so that the length of the extension section of the lock rod 520 in the lock rod hole 204 is increased. In this way, the higher water level in the manhole 100 promotes the extension of the lock rod 520, thereby improving the stability. The buoyancy block 540 is in the shape of a disk, and its upper surface is in contact with the lock plate 510. Its thickness gradually decreases from the middle to the edge, forming a streamlined shape. Even if it is immersed in water, it has less resistance to water flow.

[0053] like Figure 4 To prevent overflow, the inner diameter of the guide unlocking hole 301 gradually decreases from its lower end to its upper end, and the unlocking push rod 550 is shaped to match the shape of the guide unlocking hole 301 and does not pass through the upper end of the guide unlocking hole 301. In this way, when the water level in the manhole 100 is high, the buoyancy block 540 rises, and the lock plate 510 and the unlocking push rod 550 also rise accordingly, and the fit with the inner wall of the guide unlocking hole 301 is higher, thereby preventing water from overflowing from the guide unlocking hole 301.

[0054] like Figure 3 and 4 As shown, in order to ensure that the locking rod 520 has a stable route when entering and exiting the locking rod hole 204, a locking ring 310 is fixedly provided on the lower surface of the manhole cover 300, the locking ring 310 is close to the inner wall of the wellhead, the locking ring 310 corresponds to the locking rod hole 204 one by one, and the opening of the locking rod hole 204 is directly connected to the inner hole of the locking ring 310. The locking rod 520 passes through the corresponding locking ring 310 and is inserted into the corresponding locking rod hole 204, and the locking rod hole 204 guides the movement of the locking rod 520.

[0055] To further improve the stability of the manhole cover 300 when it is locked: Figures 6 to 8As shown, the lock ring 310 includes an n-shaped frame 311, which is fixedly connected to the manhole cover 300, and an anti-slip rod 312 is connected between the free ends of the two arms of the n-shaped frame 311, and the anti-slip rod 312 and the n-shaped frame 311 form the lock ring 310. The anti-slip rod 312 is connected to the corresponding locking rod 520 through a limit connecting rod 530, and a strip hole 521 is opened on the locking rod 520 corresponding to the limit connecting rod 530, and one end of the limit connecting rod 530 is connected to a hinge column, which is inserted into the strip hole 521, and the other end of the limit connecting rod 530 is hinged to the anti-slip rod 312. When the outer end of the locking rod 520 is inserted into the locking rod hole 204, the hinge column of the limiting link 530 is closer to the locking rod hole 204 than the anti-dropout rod 312 to form an anti-dropout dead point to prevent the locking rod 520 from falling out when the manhole cover 300 is subjected to an upward force.

[0056] like Figure 4 As shown, the locking rod hole 204 is a wedge-shaped hole, the end with a larger inner diameter of the locking rod hole 204 is an open end, the top of the inner wall of the locking rod hole 204 is inclined, and the top of the inner wall of the locking rod hole 204 extends obliquely upward to the upper edge of the inner hole near the locking ring 310. The upper surface of the outer end of the locking rod 520 is a wedge-shaped inclined surface adapted to the locking rod hole 204. The purpose of such a design is to adapt to the movement trajectory of the locking rod 520, that is, the upward movement of the lock plate 510 drives the inner end of the locking rod 520 to rotate upward, and the outer end of the locking rod 520 moves outward and rotates downward, so that the locking rod 520 can enter the locking rod hole 204 conveniently. At the same time, an inclined wedge mechanism is formed between the wedge-shaped hole and the wedge inclined surface, so that when the outer end of the locking rod 520 enters the locking rod hole 204, the outer end of the locking rod 520 drives the limiting link 530 downward, pressing down the anti-slip rod 312, thereby increasing the downward pressure on the locking ring 310, which is transmitted to the manhole cover 300, pressing the manhole cover 300 tightly against the installation step.

[0057] The locking rod 520 is an arc-shaped rod that bends upward, and the upper surface of the locking rod 520 smoothly transitions with the wedge slope. This design facilitates the locking rod 520 to enter and slide out of the locking rod hole 204 when unlocking.

[0058] In this embodiment, Figure 6 and 7 As shown, the inner wall of the wellhead of the manhole 100 is provided with three locking rod holes 204, and the three locking rod holes 204 are evenly distributed circumferentially on the inner wall of the manhole 100. The manhole cover (300) is correspondingly connected with three locking rings 310 and locking rods 520.

[0059] like Fig. 9As shown, the wellhead seat ring 200 includes a vertical tube 201 and a horizontal ring 202. The lower edge of the vertical tube 201 is connected to the outer edge of the horizontal ring 202 to form the wellhead seat ring 200. The inner side wall of the wellhead seat ring 200 forms a mounting step, and the manhole cover 300 falls on the mounting step. The manhole cover 300 is adapted to the inner cavity of the vertical tube 201.

[0060] A locking block 203 is integrally formed on the lower surface of the horizontal ring 202 of the wellhead seat ring 200, and a locking rod hole 204 is formed on the locking block 203. In this way, the processing quality can be controlled during processing so that the locking rod hole 204 and the well cover 300 and the locking ring 310 have a better fit, and the installation is also convenient, without the need to separately process the locking rod hole 204 on the well wall.

[0061] like Fig.10 and 11 As shown, the elastic sealing ring 400 is in the shape of a ring sleeve, the outer side of the elastic sealing ring 400 is against the cylindrical inner wall of the installation step, and the inner side of the elastic sealing ring 400 is against the annular side wall of the manhole cover 300. The elastic sealing ring 400 includes a sealing ring body 401, and the two edges of the lower end surface of the sealing ring body 401 extend downward along the outer side and the inner side of the sealing ring body 401 respectively to form two outer and inner fitting parts 402, and the area between the two fitting parts 402 forms an anti-backflow cavity.

[0062] The inner wall of the vertical tube 201 is inclined, and the inclination angle is 5° to 15°. Specifically, the angle between the straight line formed by the intersection of any plane passing through the center line of the vertical tube 201 and the inner circumferential surface of the vertical tube 201 and the center line of the vertical tube 201 is 5 to 15. In this way, its inner diameter gradually decreases from top to bottom. When the manhole cover 300 is moved downward by the force, the distance between the manhole cover 300 and the inner circumferential surface of the vertical tube 201 is reduced, and the sealing ring body 401 is compressed, and the fit between the manhole cover 300 and the vertical tube 201 is tighter, thereby improving the sealing. This effect is particularly obvious when the buoyancy block 540 pushes the lock plate 510 upward under the action of buoyancy.

[0063] The thickness of the fitting portion 402 gradually decreases from the sealing ring body 401 to its free edge. The width of the fitting portion 402 located on the inner side is smaller than the width of the fitting portion 402 located on the outer side. In this way, when a small amount of water overflows, it is easier to enter the anti-backflow cavity, and the two fitting portions 402 are stretched open under the action of water pressure, so that they are pressed against the inner side wall of the wellhead seat ring 200 or the annular side wall of the well cover 300.

[0064] The sealing ring body 401 is penetrated by a seepage hole 403 , one end of the seepage hole 403 opens at the end surface of the sealing ring body 401 facing the anti-backflow cavity, and the other end of the seepage hole 403 opens at the other end surface of the sealing ring body 401 .

[0065] The cross section of the seepage hole 403 is elliptical, and the longer inner diameter of the seepage hole 403 is distributed along the circumferential direction of the sealing ring body 401. Under normal conditions, the seepage hole 403 is in a passage state, and a small amount of water flow on the ground can enter the manhole 100 through the seepage hole 403, and it does not affect the escape of a small amount of gas in the manhole 100; when the manhole cover 300 is pressed down, the seepage hole 403 is closed. The elastic sealing ring 400 is made of rubber material.

[0066] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, ordinary technicians in this field can make various similar expressions without violating the purpose and claims of the present invention, and such changes all fall within the scope of protection of the present invention.

Claims

1. A safety sealed drainage system, comprising a drainage pipe (600), wherein a manhole (100) is arranged on the drainage pipe (600), wherein the manhole (100) divides the drainage pipe (600) into an upstream pipe section (601) and a downstream pipe section (602), wherein the upstream pipe section (601) and the downstream pipe section (602) are respectively connected to the manhole (100), and the manhole (100) is covered with a manhole cover (300), wherein: The wellhead of the manhole (100) is fixedly provided with a wellhead seat ring (200), a wellhead cover (300) is provided on the wellhead seat ring (200), and an elastic sealing ring (400) is provided between the wellhead cover (300) and the wellhead seat ring (200); A locking mechanism is provided between the manhole cover (300) and the manhole (100), and an external unlocking mechanism is provided between the locking mechanism and the manhole cover (300); The locking mechanism comprises a locking rod hole (204), a locking plate (510), a locking rod (520) and a tension spring (560); At least two locking rod holes (204) are formed on the inner wall of the wellhead of the manhole (100), and the locking rod holes (204) are evenly distributed in an annular direction on the inner wall of the manhole (100); The locking disk (510) is connected to the middle of the lower surface of the manhole cover (300), the locking disk (510) is arranged horizontally, the locking rod (520) is connected to the upper surface of the locking disk (510), the locking rod (520) corresponds to the locking rod hole (204) one by one, the locking rod (520) is arranged radially along the locking disk (510), the inner end of the locking rod (520) is hinged to the locking disk (510), and the outer end of the locking rod (520) is inserted into the corresponding locking rod hole (204); The locking plate (510) is suspended below the manhole cover (300) via a tension spring (560), and the tension spring (560) maintains the locking rod (520) inserted into the locking rod hole (204); A buoyancy block (540) is disposed on the lower surface of the locking plate (510). When the buoyancy block (540) is subjected to an upward buoyancy force, it pushes the locking plate (510) upward, driving the locking rod (520) to move upward and rotate, so that the length of the locking rod (520) extending into the locking rod hole (204) increases; The external unlocking mechanism comprises a guide unlocking hole (301), which vertically penetrates the middle of the manhole cover (300), and an unlocking push rod (550) is movably inserted into the guide unlocking hole (301). The unlocking push rod (550) is fixedly arranged on the upper surface of the lock disk (510), and the unlocking push rod (550) freely passes through the tension spring (560).

2. A safety sealed drainage system according to claim 1, characterized in that: The inner diameter of the guide unlocking hole (301) gradually decreases from its lower end to its upper end, and the shape of the unlocking push rod (550) is adapted to the shape of the guide unlocking hole (301) and does not pass through the upper end of the guide unlocking hole (301).

3. A safety sealed drainage system according to claim 1, characterized in that: A locking ring (310) is fixedly arranged on the lower surface of the manhole cover (300), the locking ring (310) is close to the inner wall of the wellhead, the locking ring (310) corresponds to the locking rod hole (204) one by one, and the opening of the locking rod hole (204) is directly connected to the inner hole of the locking ring (310); The locking rod (520) passes through the corresponding locking ring (310) and is inserted into the corresponding locking rod hole (204).

4. A safety sealed drainage system according to claim 3, characterized in that: The locking ring (310) comprises an n-shaped frame (311), the n-shaped frame (311) is fixedly connected to the manhole cover (300), an anti-slip rod (312) is connected between the free ends of the two arms of the n-shaped frame (311), and the anti-slip rod (312) and the n-shaped frame (311) form the locking ring (310); The anti-slip rod (312) is connected to the corresponding locking rod (520) via a limiting link (530); a strip hole (521) is provided on the locking rod (520) corresponding to the limiting link (530); one end of the limiting link (530) is connected to a hinge column which is inserted into the strip hole (521); the other end of the limiting link (530) is hinged to the anti-slip rod (312).

5. A safety sealed drainage system according to claim 3, characterized in that: The locking rod hole (204) is a wedge-shaped hole, the end with a larger inner diameter of the locking rod hole (204) is an open end, the top of the inner wall of the locking rod hole (204) is inclined, and the top of the inner wall of the locking rod hole (204) extends obliquely upward to the upper edge of the inner hole close to the locking ring (310); The upper surface of the outer end of the locking rod (520) is a wedge-shaped inclined surface adapted to the locking rod hole (204).

6. A safety sealed drainage system according to claim 1, characterized in that: The wellhead seat ring (200) comprises a vertical cylinder (201) and a horizontal ring (202), the lower edge of the vertical cylinder (201) is connected to the outer edge of the horizontal ring (202) to form the wellhead seat ring (200), the inner side wall of the wellhead seat ring (200) forms a mounting step, the wellhead cover (300) falls on the mounting step, and the wellhead cover (300) is adapted to the inner cavity of the vertical cylinder (201); The elastic sealing ring (400) is in the shape of a ring sleeve, the outer side surface of the elastic sealing ring (400) is in contact with the cylindrical inner wall of the installation step, and the inner side surface of the elastic sealing ring (400) is in contact with the annular side wall of the manhole cover (300); The elastic sealing ring (400) comprises a sealing ring body (401), the two edges of the lower end surface of the sealing ring body (401) respectively extending downward along the outer side surface and the inner side surface of the sealing ring body (401) to form two outer and inner fitting parts (402), and the area between the two fitting parts (402) forms an anti-backflow cavity.

7. A safety sealed drainage system according to claim 6, characterized in that: The inner wall of the vertical tube (201) is inclined, with an inclination angle of 5° to 15°.

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