An apparatus for blocking large-diameter drainage pipes and its usage method

Abstract

The present invention relates to a device for blocking a large-diameter drainage pipe and a method for using the same. A well chamber is provided on the large-diameter drainage pipe. The well chamber includes a wellbore and a wellhead provided at the top of the wellbore. The wellhead is communicated with the wellbore, and the bottom of the wellbore is communicated with the large-diameter drainage pipe. The device includes a hydraulic support device, an intermediate connection device, and a blocking device. The hydraulic support device is connected to the blocking device through the intermediate connection device. The front end of the device is dragged by a wire rope at the upstream wellhead, and the tail is lowered into the large-diameter drainage pipe at the bottom of the wellbore from the wellhead of the blocking operation through another wire rope. Under the action of a plurality of hydraulic cylinders, actions such as connection, support, and blocking are realized. It not only has a reasonable structural design, the ability to transform greatly, reliable blocking ability and support ability, but also has the ability to block against the water flow direction (water-facing end), which is convenient for judging the effectiveness of blocking and support, and is beneficial to the safety of downstream maintenance operations and other advantages.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal pipeline construction, and particularly to a device for blocking large-diameter drainage pipelines and a method for using the same. Background Art

[0002] Large-diameter pipelines for drainage are mostly located deep in the underground soil. Due to being buried underground for a long time, most of the pipelines face problems such as aging, corrosion, and settlement. In severe cases, it will even affect the drainage function of the pipeline. Therefore, it is necessary to transform and update the problematic pipelines to restore their original drainage capacity. Before maintenance, it is necessary to complete water blocking upstream to ensure the safety of downstream pipeline maintenance operations. However, due to the actual situation of large-diameter drainage pipelines with large pipe diameters and small wellheads, it is easy to cause difficulties in lowering the blocking device into the well, and the blocking device needs to have a large transformation ability; the blocking device should have sufficient blocking ability and supporting ability to ensure the safety of downstream maintenance operations. The current blocking methods and devices are difficult to meet the above requirements. Previously, the applicant found through retrieval that the patent application number: 201710855487.5 discloses a pipeline blocking device, which includes an in-pipe sealing device and a positioning and strengthening device, and is connected by an equalizing connection device. The in-pipe sealing device is an inflatable elastic airbag, and the positioning and strengthening device is an electric push rod driving a support rod to open, and is supported and positioned by friction blocks contacting the inner wall of the pipeline. The equalizing connection device is equipped with a wire locking block and is connected to the airbag through a wire. Although this device can be applied to different pipe diameters, the overall inner diameter of the pipeline is relatively small. To ensure that the wire is tightened and stressed, this device can only block the downstream wellhead and is not suitable for high-intensity underground operations. The present invention is precisely proposed based on the above research background, aiming to provide a device and a method for using the same for blocking large-diameter drainage pipelines to meet the actual design and use needs. Summary of the Invention

[0003] Aiming at the above deficiencies existing in the prior art, the purpose of the present invention is to provide a device for blocking large-diameter drainage pipelines and a method for using the same, which not only has a reasonable structural design, has the ability of large transformation, reliable blocking ability and supporting ability, but also has the ability to perform blocking in the direction of the water flow (the water-facing end), which is convenient for judging the effectiveness of blocking and supporting, and is beneficial to the safety of downstream maintenance operations and other advantages.

[0004] To achieve the above purpose, the present invention is realized by adopting the following technical solutions:

[0005] A device for blocking a large-diameter drainage pipe, a well chamber is provided on the large-diameter drainage pipe, the well chamber includes a wellbore and a wellhead provided at the top of the wellbore, the wellhead is communicated with the wellbore, and the bottom of the wellbore is communicated with the large-diameter drainage pipe; the device includes a hydraulic support device, an intermediate connection device and a blocking device, and the hydraulic support device is connected to the blocking device through the intermediate connection device; the front end of the device is dragged by a steel wire rope at the upstream wellhead, and the tail is hoisted into the large-diameter drainage pipe at the bottom of the wellbore through a steel wire rope at the wellhead.

[0006] As a further optimization of the above solution, the hydraulic support device includes an active parallelogram rod mechanism and a support shackle; the active parallelogram rod mechanism includes a hydraulic cylinder, a hydraulic cylinder sleeve, a plurality of drive rods and follower rods, a plurality of support arc plates, and a plurality of support step plates; the support shackle is installed at the rear end of the hydraulic cylinder of the hydraulic support device and is connected to the connection shackle of the intermediate connection device and the steel wire rope for traction; the hydraulic cylinder sleeve is sleeved outside the hydraulic cylinder, and one end of the hydraulic cylinder is provided with a hydraulic cylinder piston rod; one end of the drive rod is hinged to the hydraulic cylinder piston rod and is vertically arranged in a divergent manner on the outer peripheral surface of the driving end of the hydraulic cylinder piston rod; the other end of the drive rod is hinged to the middle of the follower rod; one end of the follower rod is hinged to the outer peripheral surface of the hydraulic cylinder, and the other end is hinged to the support arc plate and the support step plate; the vertical position of the support step plate in the large-diameter drainage pipe is higher than that of the support arc plate.

[0007] As a further optimization of the above solution, the number of the support arc plates is more than that of the support step plates. Each support step plate includes a small end and a large end. The distance between the small end and the hydraulic cylinder is less than the inner diameter of the large-diameter drainage pipe, and the distance between the large end and the hydraulic cylinder is greater than the inner diameter of the large-diameter drainage pipe.

[0008] As a further optimization of the above solution, a plurality of welding blocks are welded on the hydraulic cylinder, and the hydraulic cylinder sleeve is fixedly arranged on the connecting plate of the hydraulic cylinder through the welding blocks. Such a setting can ensure that the hydraulic cylinder sleeve cannot move axially and ensure the smooth movement of the parallelogram mechanism. Among them, two groups of welding blocks are grooved and a connecting plate is added to ensure that the hydraulic cylinder sleeve has no circumferential rotation.

[0009] As a further optimization of the above solution, the intermediate connection device includes a square bracket, a bell mouth, a small hydraulic cylinder, an insertion pin, and a fixing pin; the square bracket is bolted to the hydraulic support device through a rear flange; the small hydraulic cylinder is installed in the axial direction of the square bracket, and the front end of the push rod of the small hydraulic cylinder is fixedly provided with the insertion pin; one end of the bell mouth is bolted to the plugging device through a front flange, and this end of the bell mouth is also hinged to the square bracket through a fixing pin, and the other end of the bell mouth can be in contact connection with the insertion pin; when the small hydraulic cylinder is in the retracted state, the insertion pin does not enter the bell mouth, and the intermediate connection device itself can rotate around the fixing pin, so that the entire plugging device can rotate around the fixing pin, facilitating the lowering of the entire plugging device into the well; when the push rod of the small hydraulic cylinder extends to make the insertion pin abut against the bell mouth, due to the combined action of the insertion pin and the fixing pin, the entire plugging device forms a whole, and the central axes of the intermediate connection device and the plugging device are on the same straight line as the central axis of the hydraulic support device.

[0010] As a further optimization of the above solution, the intermediate connection device further includes a connecting shackle. An earring is welded on the square bracket at a certain angle in both the radial and axial directions of the pipeline. The connecting shackle is installed on the earring. When the equipment is lowered to the bottom of the wellbore, by pulling the towing rope on the connecting shackle, it cooperates with the towing rope on the rear shackle of the support device, so as to adjust the circumferential direction of the entire device and ensure that the support step plate of the support device is at the uppermost position of the support device.

[0011] As a further optimization of the above solution, the plugging device includes a rubber bladder, a plugging hydraulic cylinder, a driven parallelogram rod mechanism, a compression spring, a linear thrust bearing, a hydraulic cylinder liner, and a towing ring; the hydraulic cylinder liner is arranged on the outer peripheral surface of the plugging hydraulic cylinder, and one end of the plugging hydraulic cylinder is provided with a hydraulic cylinder piston rod. The driven parallelogram rod mechanism includes a number of plugging driving rods and plugging driven rods, and two groups of circumferentially misaligned plugging arc plates. One end of the plugging driving rod is hinged to the hydraulic cylinder piston rod and is vertically arranged in a divergent manner on the outer peripheral surface of the driving end of the hydraulic cylinder piston rod; the other end of the plugging driving rod is hinged to the middle of the plugging driven rod; one end of the driven rod is hinged to the outer peripheral surface of the hydraulic cylinder, and the other end is hinged to the plugging arc plate; the rubber bladder is fixed on the front end plate of the plugging device, covering the driven parallelogram rod mechanism and the plugging arc plate, and the rear end of the rubber bladder is tied to the linear thrust bearing; both ends of the compression spring are respectively abutted against the linear thrust bearing and the hydraulic cylinder piston rod. The compression spring and the linear thrust bearing work together to ensure that the rubber bladder is in a taut state when the plugging device is in the deployed and retracted states; the two groups of circumferentially misaligned plugging arc plates form a complementary state on the circumference after the plugging device is deployed, achieving the effect that the plugging arc plates are pressed against the inner wall of the large-diameter drainage pipe throughout a relatively complete circle; a towing ring is installed at the rear end of the plugging device, and the towing ring is connected to the towing steel wire rope. The large-diameter drainage pipe plugging device is dragged into the pipe by the ground equipment at the previous wellhead.

[0012] A method for using the above device for plugging a large-diameter drainage pipe, the method comprising the following steps:

[0013] 1) Lower the entire device through the towing steel wire rope until the entire device reaches the bottom of the well; while lowering, pull the shackle of the intermediate connecting device through the steel wire rope to make the support step plate of the support device above the hydraulic support device, ensuring that the support step plate can catch the inner wall of the well chamber after the support device is opened;

[0014] 2) When the plugging device is pulled into the pipe by the towing steel wire rope and the support device is still within the well chamber range, the towing steel wire rope stops working;

[0015] 3) The small hydraulic cylinder of the intermediate connecting device works to insert the insertion pin into the bell mouth, connecting the three devices of the plugging device into a whole; the hydraulic cylinder of the hydraulic support device works to open the hydraulic support device;

[0016] 4) The plugging hydraulic cylinder of the plugging device works, causing the umbrella ribs to fully open and support the leather bag to closely adhere to the inner wall of the drainage pipe, and making the overall device horizontal. Due to the insufficient friction between the plugging device and the drainage pipe, under the action of the water flow, during the opening process of the plugging device, the overall equipment will slide downstream until the support step plate on the upper part of the hydraulic support device is stuck to the left inner wall of the well chamber. With the coordinated action of the three devices, the plugging and support work at the water-facing end of the drainage pipe is finally completed.

[0017] The equipment and its usage method for plugging large-diameter drainage pipes of the present invention have the following beneficial effects:

[0018] (1) The structure of the present invention is reasonably designed, capable of plugging large-diameter drainage pipes and achieving plugging at the water-facing end. The hydraulic support device adopts a combination of a support arc plate and a support step plate. At the same time, when the stepped arc plate works, it can be stuck to the inner wall of the well chamber, with a large support force and not relying on friction. At the same time, it also avoids damaging the well chamber and the pipeline, and the support is safer and more reliable.

[0019] (2) The middle connecting device of the present invention can achieve relative rotation in the middle of the entire device, facilitating lowering. The design of the insertion pin can better connect the support device and the plugging device, making the three devices form a whole. The plugging device adopts a rigid support rod to support the leather bag, with a greater plugging strength. At the same time, it adopts a two-group plugging arc plate structure, which is complementary in the circumferential direction and has a better water-blocking effect.

[0020] (3) The entire device of the present invention is detachable, convenient for replacement and assembly, with simple operation, high construction efficiency, low construction cost, capable of plugging different pipe diameters, having a good plugging effect, and can adapt to more severe pipeline environments and higher strength requirements for underground operations. Description of the Drawings

[0021] Appendix Figure 1 It is a schematic diagram of the working process of the equipment for plugging large-diameter drainage pipes of the present invention. Among them, Figure (a) is a schematic diagram of the state when the entire equipment starts to be lowered; Figure (b) is a schematic diagram of the state when the entire equipment is completely lowered to the bottom of the well (the movable pin in the middle connecting device is inserted); Figure (c) is a schematic diagram of the state when the hydraulic support device in the entire equipment is opened; Figure (d) is a schematic diagram of the state when the plugging device in the entire equipment starts to work; Figure (e) is a schematic diagram of the state when the entire equipment is plugged.

[0022] Appendix Figure 2 It is a schematic diagram of the main structure of the equipment for plugging large-diameter drainage pipes of the present invention.

[0023] Appendix Figure 3 It is a schematic diagram of the structure of the hydraulic support device of the equipment for plugging large-diameter drainage pipes of the present invention.

[0024] Appendix Figure 4For Figure 3 Schematic enlarged view of the structure at position A in

[0025] Appendix Figure 5 Schematic structural view of the intermediate connecting device of the equipment for plugging large-diameter drainage pipes according to the present invention.

[0026] Appendix Figure 6 Schematic structural view of the plugging device of the equipment for plugging large-diameter drainage pipes according to the present invention.

[0027] Appendix Figure 7 Schematic structural view of the equipment for plugging large-diameter drainage pipes according to the present invention when the hydraulic support device abuts against the inner wall of the well chamber. Detailed implementation mode

[0028] The following will Figure 1-7 make a detailed description of the equipment for plugging large-diameter drainage pipes according to the present invention and its usage method with reference to the appendix.

[0029] A device for plugging large-diameter drainage pipes. There is a well chamber 1 provided on the large-diameter drainage pipe. The well chamber includes a wellbore and a wellhead provided at the top of the wellbore. The wellhead is communicated with the wellbore, and the bottom of the wellbore is communicated with the large-diameter drainage pipe 2. The device includes a hydraulic support device 3, an intermediate connection device 4 and a plugging device 5. The hydraulic support device is connected to the plugging device through the intermediate connection device. The front end of the device is dragged by a steel wire rope from the upstream wellhead, and the tail is hoisted from the wellhead where the plugging operation is carried out to the large-diameter drainage pipe at the bottom of the wellbore through another steel wire rope. The hydraulic support device includes an active parallelogram rod mechanism and a support shackle 12. The active parallelogram rod mechanism includes a hydraulic cylinder 6, a hydraulic cylinder liner 7, a number of driving rods 8 and driven rods 9, a number of support arc plates 10, and a number of support step plates 11. The support shackle is installed at both ends of the hydraulic cylinder of the hydraulic support device and is respectively connected to the connection shackle of the intermediate connection device and the steel wire rope for traction. The hydraulic cylinder liner is sleeved outside the hydraulic cylinder, and one end of the hydraulic cylinder is provided with a hydraulic cylinder piston rod. One end of the driving rod is hinged to the hydraulic cylinder piston rod and is vertically arranged in a divergent manner on the outer peripheral surface of the driving end of the hydraulic cylinder piston rod. The other end of the driving rod is hinged to the middle of the driven rod. One end of the driven rod is hinged to the outer peripheral surface of the hydraulic cylinder, and the other end is hinged to the support arc plate and the support step plate. The vertical position of the support step plate in the large-diameter drainage pipe is higher than that of the support arc plate. The number of support arc plates is more than that of support step plates. Each support step plate includes a small end and a large end. The distance between the small end and the hydraulic cylinder is less than the inner diameter of the large-diameter drainage pipe, and the distance between the large end and the hydraulic cylinder is greater than the inner diameter of the large-diameter drainage pipe. A number of welding blocks 13 are welded on the hydraulic cylinder, and the hydraulic cylinder liner is fixedly arranged on the connecting plate 14 of the hydraulic cylinder through the welding blocks. The intermediate connection device includes a square bracket 15, a bell mouth 16, a small hydraulic cylinder 17, an insertion pin 18, and a fixing pin 19. The square bracket is bolted to the hydraulic support device through a rear flange 20. The small hydraulic cylinder is axially installed on the square bracket, and the front end of the push rod of the small hydraulic cylinder is fixedly provided with the insertion pin. One end of the bell mouth is bolted to the plugging device through a front flange 21, and this end of the bell mouth is also hinged to the square bracket through the fixing pin. The other end of the bell mouth can be abutted and connected to the insertion pin. In the retracted state of the small hydraulic cylinder, the insertion pin does not enter the bell mouth, and the intermediate connection device itself can rotate around the fixing pin, so that the entire plugging device can rotate around the fixing pin, which is convenient for the entire plugging device to go down the well. When the push rod of the small hydraulic cylinder extends to make the insertion pin abut against the bell mouth, due to the combined action of the insertion pin and the fixing pin, the entire plugging device forms a whole, and the central axes of the intermediate connection device and the plugging device are on the same straight line as the central axis of the hydraulic support device.The intermediate connecting device further includes a connecting shackle 22. An earring is welded on the square bracket at a certain angle with respect to both the radial and axial directions of the pipeline. The shackle is installed on the earring. When the device is lowered to the bottom of the wellbore, by pulling the towing rope on the shackle, it cooperates with the towing rope on the shackle at the rear end of the support device, so as to adjust the circumferential direction of the entire device and ensure that the support step plate of the support device is at the uppermost position of the support device. The plugging device includes a rubber bladder 23, a plugging hydraulic cylinder 24, a driven parallelogram link mechanism, a compression spring 25, a linear thrust bearing 26, a hydraulic cylinder sleeve, and a towing ring 27. The hydraulic cylinder sleeve is arranged on the outer peripheral surface of the plugging hydraulic cylinder, and one end of the plugging hydraulic cylinder is provided with a hydraulic cylinder piston rod. The driven parallelogram link mechanism includes a number of plugging driving rods 28 and plugging driven rods 29, and two groups of circumferentially offset plugging arc plates. One end of the plugging driving rod is hinged to the hydraulic cylinder piston rod and is vertically arranged in a divergent manner on the outer peripheral surface of the driving end of the hydraulic cylinder piston rod. The other end of the plugging driving rod is hinged to the middle of the plugging driven rod. One end of the driven rod is hinged to the outer peripheral surface of the hydraulic cylinder, and the other end is hinged to the plugging arc plate. The rubber bladder is fixed on the front end plate of the plugging device and covers the driven parallelogram link mechanism and the plugging arc plate. The rear end of the rubber bladder is tied to the linear thrust bearing. The two ends of the compression spring are respectively abutted against the linear thrust bearing and the hydraulic cylinder piston rod. The compression spring and the linear thrust bearing act together to ensure that the rubber bladder is in a taut state when the plugging device is in the deployed and retracted states. The two groups of circumferentially offset plugging arc plates form a complementary state on the circumference after the plugging device is deployed, achieving the effect that the plugging arc plates tightly abut against the inner wall of the large-diameter drainage pipe throughout a relatively complete circle. A towing ring is installed at the rear end of the plugging device, and the towing ring is connected to the towing steel wire rope. The large-diameter drainage pipe plugging device is dragged into the pipe by the ground equipment at the upper wellhead.

[0030] The usage method of the above-described device for plugging large-diameter drainage pipes according to the present invention includes the following steps:

[0031] 1) Lower the entire device through the towing steel wire rope until the entire device reaches the bottom of the well; while lowering, pull the shackle of the intermediate connecting device through the steel wire rope to make the support step plate of the support device above the hydraulic support device, ensuring that the support step plate can catch the inner wall of the well chamber after the support device is opened;

[0032] 2) When the plugging device is pulled into the pipe by the towing steel wire rope and the support device is still within the well chamber range, the towing steel wire rope stops working;

[0033] 3) The small hydraulic cylinder of the intermediate connecting device works to insert the insertion pin into the bell mouth, so that the three devices of the plugging device are fixed into a whole; the hydraulic cylinder of the hydraulic support device works to open the hydraulic support device;

[0034] 4) The sealing hydraulic cylinder of the sealing device works to fully open the ribs to prop up the leather bag and press it against the inner wall of the drain pipe, and to keep the whole device horizontal. Due to the insufficient friction between the sealing device and the drain pipe, under the action of the water flow, the whole equipment will slide downstream during the opening of the sealing device until the supporting step plate on the upper part of the hydraulic support device is stuck to the inner wall on the left side of the well chamber. With the coordinated action of the three devices, the sealing and supporting work of the water-facing end of the drain pipe is finally completed.

[0035] The present invention provides a device and a method for blocking a large-diameter drainage pipe, which is characterized in that it can block the large-diameter drainage pipe under non-excavation conditions, and can achieve blocking of the water-facing end, providing safe and reliable construction conditions for pipeline repair and emergency rescue, and has the characteristics of simple operation, high construction efficiency, low construction cost, ability to block different pipe diameters, good blocking effect, etc. At the same time, the present invention also realizes the characteristic of variable diameter of the device through the combination of hydraulic cylinder and rod, and solves the design problem that the large-diameter drainage pipe has a large diameter and a small wellhead, and the blocking device cannot be lowered; at the same time, the large-diameter drainage blocking device is equipped with an intermediate connecting device, so that the whole device can achieve relative rotation in the middle, solving the problem that the whole device is too long to enter the pipeline in the well chamber; the hydraulic support device adopts a combination of a supporting arc plate and a supporting step plate, which is conducive to the coaxiality of the blocking device and the pipeline, and the supporting force is large without relying on friction, avoiding damage to the well chamber and the pipeline, and is safe and reliable; the blocking device adopts two sets of blocking arc plate structures, which are complementary in the circumferential direction and have a good water blocking effect. At the same time, the large-diameter drainage pipe plugging device adopts a detachable structure, which is convenient for replacement and assembly.

[0036] The above description of the embodiments is to facilitate the understanding and application of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. An apparatus for plugging a large-diameter drainage pipe, wherein a well chamber is provided on the large-diameter drainage pipe, the well chamber includes a wellbore and a wellhead provided at the top of the wellbore, the wellhead is communicated with the wellbore, and the bottom of the wellbore is communicated with the large-diameter drainage pipe; characterized in that: The device includes a hydraulic support device, an intermediate connection device, and a plugging device. The hydraulic support device is connected to the plugging device through the intermediate connection device. The front end of the device is dragged by a wire rope at the upstream wellhead, and the tail is lowered from the wellhead of the plugging operation to the large-diameter drainage pipeline at the bottom of the wellbore through another wire rope. The hydraulic support device includes an active parallelogram rod mechanism and a support shackle. The active parallelogram rod mechanism includes a hydraulic cylinder, a hydraulic cylinder sleeve, a number of drive rods and follower rods, a number of support arc plates, and a number of support stepped plates. The support shackle is installed at the rear end of the hydraulic cylinder of the hydraulic support device and is connected to the connection shackle of the intermediate connection device and the wire rope for traction. The hydraulic cylinder sleeve is sleeved outside the hydraulic cylinder, and one end of the hydraulic cylinder is provided with a hydraulic cylinder piston rod. One end of the drive rod is hinged to the hydraulic cylinder piston rod and is vertically arranged in a divergent manner on the outer peripheral surface of the drive end of the hydraulic cylinder piston rod. The other end of the drive rod is hinged to the middle of the follower rod. One end of the follower rod is hinged to the outer peripheral surface of the hydraulic cylinder, and the other end is hinged to the support arc plate and the support stepped plate. The vertical position of the support stepped plate in the large-diameter drainage pipeline is higher than that of the support arc plate. The number of support arc plates is more than that of the support stepped plates. Each support stepped plate includes a small end and a large end. The distance from the small end to the central axis of the hydraulic cylinder is less than the inner radius of the large-diameter drainage pipe, and the distance from the large end to the central axis of the hydraulic cylinder is greater than the inner radius of the large-diameter drainage pipeline. A number of welding blocks are welded on the hydraulic cylinder, and the hydraulic cylinder sleeve is fixedly arranged on the connecting plate of the hydraulic cylinder through the welding blocks. The intermediate connection device includes a square bracket, a bell mouth, a small hydraulic cylinder, an insertion pin, and a fixing pin. The square bracket is bolted to the hydraulic support device through the rear flange. A small hydraulic cylinder is installed in the axial direction of the square bracket, and the front end of the push rod of the small hydraulic cylinder is fixedly provided with an insertion pin. One end of the bell mouth is bolted to the plugging device through the front flange, and this end of the bell mouth is also hinged to the square bracket through a fixing pin. The other end of the bell mouth can be in contact with the insertion pin. When the small hydraulic cylinder is in the retracted state, the insertion pin does not enter the bell mouth, and the intermediate connection device itself can rotate around the fixing pin, so that the entire plugging device can rotate around the fixing pin, facilitating the lowering of the entire plugging device into the well. When the push rod of the small hydraulic cylinder extends to make the insertion pin abut against the bell mouth, due to the combined action of the insertion pin and the fixing pin, the entire plugging device forms a whole, and the central axes of the intermediate connection device and the plugging device are on the same straight line as the central axis of the hydraulic support device.

2. The device for blocking large-diameter drainage pipes according to claim 1, characterized in that: The intermediate connection device also includes a connection shackle. Earrings are welded on the square bracket at a certain angle with respect to both the radial and axial directions of the pipeline. The connection shackle is installed on the earrings. When the device is lowered to the bottom of the wellbore, by pulling the traction rope on the connection shackle, it cooperates with the traction rope on the support shackle at the rear end of the support device, thereby adjusting the circumferential direction of the entire device and ensuring that the support stepped plate of the support device is at the uppermost position of the support device.

3. The device for blocking a large-diameter drainage pipe according to claim 2, characterized in that: The plugging device includes a rubber bag, a plugging hydraulic cylinder, a driven parallelogram link mechanism, a compression spring, a linear thrust bearing, a hydraulic cylinder sleeve, and a towing ring; the hydraulic cylinder sleeve is arranged on the outer peripheral surface of the plugging hydraulic cylinder, and one end of the plugging hydraulic cylinder is provided with a hydraulic cylinder piston rod. The driven parallelogram link mechanism includes several plugging driving rods and plugging driven rods, and two groups of circumferentially misaligned plugging arc plates. One end of the plugging driving rod is hinged to the hydraulic cylinder piston rod and is vertically arranged in a divergent manner on the outer peripheral surface of the driving end of the hydraulic cylinder piston rod; the other end of the plugging driving rod is hinged to the middle of the plugging driven rod; one end of the driven rod is hinged to the outer peripheral surface of the hydraulic cylinder, and the other end is hinged to the plugging arc plate; the rubber bag is fixed on the front end plate of the plugging device and covers the driven parallelogram link mechanism and the plugging arc plate. The rear end of the rubber bag is tied to the linear thrust bearing; both ends of the compression spring are respectively abutted against the linear thrust bearing and the hydraulic cylinder piston rod. The compression spring and the linear thrust bearing work together to ensure that the rubber bag is in a taut state when the plugging device is in the deployed and retracted states; the two groups of circumferentially misaligned plugging arc plates form a complementary state on the circumference after the plugging device is deployed, achieving the effect that the plugging arc plates are pressed against the inner wall of the large-diameter drainage pipe throughout a relatively complete circle; a towing ring is installed at the front end of the plugging device, and the towing ring is connected to the towing steel wire rope. The large-diameter drainage pipe plugging device is towed into the pipe by the ground equipment at the previous wellhead.

4. A method of using an apparatus for blocking a large-diameter drainage pipe according to any one of claims 1-3, characterized in that, The usage method includes the following steps: 1) Through the coordinated action of the lifting steel wire rope at the tail end of the equipment and the towing steel wire rope at the front end, the entire equipment is lowered until the entire device reaches the bottom of the well; while lowering, the shackle of the intermediate connection device is towed by the steel wire rope, so that the support step plate of the support device is above the hydraulic support device, ensuring that the support step plate can catch the inner wall of the well chamber after the support device is opened; 2) When the plugging device is towed into the pipe by the towing steel wire rope and the support device is still within the well chamber range, the towing steel wire rope stops working; 3) The small hydraulic cylinder of the intermediate connection device works to insert the insertion pin into the bell mouth, so that the three devices of the plugging device are fixed into a whole; 4) The hydraulic cylinder of the hydraulic support device works to open the hydraulic support device; 5) The plugging hydraulic cylinder of the plugging device works to completely open the umbrella ribs to support the rubber bag, so that the rubber bag is closely attached to the inner wall of the drainage pipe. The whole device is horizontal. Due to the insufficient friction between the plugging device and the drainage pipe, under the action of the water flow, the whole equipment will slide downstream during the opening process of the plugging device until the support step plate on the upper part of the hydraulic support device catches the inner wall of the well chamber. Under the coordinated action of the three devices, the plugging and supporting work of the water-facing end of the drainage pipe is finally completed.

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