Plugging device and method facilitating welding of upper end of well point downcast pipe

Abstract

The invention belongs to the technical field of welding, and particularly discloses a plugging device and method facilitating welding of the upper end of a well point downcast pipe, the plugging device comprises a plugging device body arranged on a water path where underground water and the downcast pipe are communicated, the plugging device body comprises a plugging part capable of being opened and closed, the plugging part is in a first state when closed, and the plugging part is in a second state when opened; only the plugging part in the first state is allowed to pass through the downcast pipe, the plugging part is inserted into the downcast pipe and moves downwards when in the first state, and the plugging part is automatically switched to the second state after moving downwards to the outside of the downcast pipe and presses and seals the lower end of the downcast pipe under the effect of underground water pressure, so that the upper end of the downcast pipe is welded and plugged in a dry environment. The problem that the welding difficulty of downcast pipe plugging is large can be effectively solved, the welding quality can be controlled, the welding plugging position is not prone to water leakage, and the construction quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of brazing, and particularly to a plugging device and method for facilitating the welding of the upper end of a well point dewatering pipe. Background Art

[0002] During the construction of high-rise buildings, due to the relatively high groundwater level and deep foundation pit excavation, the well point dewatering method is generally required for construction to lower the water level, so as to facilitate the excavation of the foundation pit and the construction of the foundation. However, when the well point dewatering equipment is removed after the foundation construction is completed, due to the action of groundwater pressure, it is difficult to plug the dewatering pipe. Generally, crushed stones are filled in the dewatering pipe, then high-strength concrete is poured, and then a thick steel plate is used to weld and seal the dewatering pipe. However, due to the large groundwater pressure, after the dewatering stops, a large amount of groundwater will still gush up, making the upper end of the dewatering pipe in a wet environment during welding, resulting in great difficulty in welding the upper end of the dewatering pipe and difficult to control the welding quality, leading to easy leakage at the welded and plugged part of the upper end of the dewatering pipe, and many potential hazards after construction. It is extremely difficult to stop the leakage of water seepage in the basement concrete floor in the future. Summary of the Invention

[0003] The purpose of the present invention is to provide a plugging device and method for facilitating the welding of the upper end of a well point dewatering pipe, which can effectively solve the problem of great difficulty in plugging and welding the dewatering pipe, the welding quality can be controlled, the welded and plugged position is not easy to leak water, and the construction quality is improved.

[0004] To solve the above technical problems, the present invention adopts the following solutions:

[0005] A plugging device for facilitating the welding of the upper end of a well point dewatering pipe includes a plugging device body arranged on the water connection path between the groundwater and the dewatering pipe. The plugging device body includes a plugging part that can open and close. When the plugging part is closed, it is in the first state, and when it is open, it is in the second state. The dewatering pipe only allows the plugging part in the first state to pass through. When the plugging part is in the first state, it is inserted into the dewatering pipe and moves downward. After the plugging part moves downward outside the dewatering pipe, it automatically switches to the second state and tightly seals the lower end of the dewatering pipe under the action of groundwater pressure, so that the upper end of the dewatering pipe is in a dry environment during welding and plugging.

[0006] In this solution, the plugging part is designed to be a structure that can open and close. When the plugging part is in the closed state (the first state), its size is small enough to pass through the diameter of the downcomer, facilitating insertion into the downcomer and relative movement with the downcomer. When the plugging part opens to the second state, its size increases and it cannot pass through the inside of the downcomer. In the initial stage, the plugging part is in the closed state and is inserted into the downcomer. As the plugging part moves downward in the downcomer, when it reaches below the bottom of the downcomer, the plugging part automatically switches from the closed state to the open state. Utilizing the water pressure of the groundwater, the plugging part closely adheres to the lower end of the downcomer, forming an effective seal. The seal depends not only on the physical contact between the plugging part and the downcomer but also on the pressure difference generated by the water pressure, making the plugging part press more firmly on the downcomer. The greater the groundwater pressure, the better the plugging effect. In this way, after stopping the dewatering, groundwater is not likely to gush out from the downcomer again. This enables the welding operation at the upper end of the downcomer to be in a dry environment, reducing the welding difficulty, improving the welding quality, and also having a better sealing effect at the upper end of the downcomer. The welded and plugged part at the upper end of the downcomer is not prone to leakage, and there are fewer potential hazards after construction. In the future, the basement concrete floor slab is also not prone to water seepage, providing construction quality.

[0007] Optionally, it further includes a push rod connected to the top end of the plugging part. The length of the push rod is greater than the length of the downcomer, and the diameter of the push rod is smaller than the inner diameter of the downcomer. An external force acts on the upper end of the push rod and drives the plugging part to move downward along the length direction of the downcomer. After the plugging part moves outside the downcomer, the external force stops.

[0008] Optionally, the lower end of the push rod is integrally formed into a first connecting column and a second connecting column. There is an inverted V-shaped opening between the first connecting column and the second connecting column. The plugging part includes a first end head and a second end head respectively corresponding to and connected to the first connecting column and the second connecting column. A telescopic diaphragm flush with the top surface of the plugging part is provided between the first end head and the second end head. Under the action of an external force, the first end head and the second end head can close, and after the external force is released, the first end head and the second end head open. A sealing ring is provided on the top surface of the plugging part, and the inner diameter of the sealing ring is greater than the diameter of the push rod.

[0009] Optionally, a spring is provided between the first end head and the second end head, and both ends of the spring act on the opposite side walls of the first end head and the second end head respectively.

[0010] Optionally, a plugging plate is sleeved on the push rod. External threads are provided on the outer wall of the push rod, and a locking nut located above the plugging plate is threadedly connected to the push rod. Rotating the locking nut causes the push rod to drive the plugging part to generate a relative upward displacement with respect to the downcomer and squeeze the sealing ring.

[0011] Optionally, a fixing block adapted to the inner diameter of the downcomer is provided on the bottom surface of the plugging plate. A sealing rubber ring is circumferentially embedded in the fixing block, and the sealing rubber ring is pressed tightly between the side wall of the fixing block and the inner wall of the downcomer.

[0012] Optionally, after the locking nut is rotated into place, the plugging plate is circumferentially welded to the top end of the downcomer, and the push rod is welded between the plugging plate and the locking nut.

[0013] Optionally, the push rod is a solid rod.

[0014] Optionally, the lower end of the closed part is in a conical shape when closed.

[0015] A plugging method includes the following steps:

[0016] Step S1: Before plugging, if there is a fine sand filter layer in the downcomer, the fine sand filter layer needs to be cleaned first. If there is no fine sand filter layer, there is no need to clean it.

[0017] Step S2: Place the lower end of the plugging part on the upper end of the downcomer, and place the sealing ring on the plugging part after passing through the push rod. At this time, the first head and the second head are in the second state. Apply a downward vertical force to the push rod through the hydraulic cylinder, so that the downcomer exerts extrusion on the first head and the second head. The first head and the second head can be inserted into the downcomer in the first state and move downward along the length direction of the downcomer under the action of the vertical force until the plugging part moves to the outside of the lower end of the downcomer. Then, retract the push rod upward so that the sealing ring contacts the lower end of the downcomer, and under the action of the groundwater pressure, press the plugging part tightly against the lower end of the downcomer so that the upper end of the downcomer is welded and plugged in a dry environment.

[0018] Step S4: Then, sleeved the plugging plate on the push rod, embed the fixing block with the sealing rubber ring into the downcomer, then thread the locking nut onto the push rod, remove the hydraulic cylinder, and then clamp the push rod with a tool to prevent the push rod from rotating when screwing the locking nut. Then, screw the locking nut with a tool and drive the push rod to generate an upward relative displacement, thereby driving the plugging part to move upward, so that the sealing ring is further pressed tightly between the lower end of the downcomer and the top end of the plugging part.

[0019] Step S5: After the locking nut is screwed into place, weld the contact position between the plugging plate and the downcomer, weld the contact position between the locking nut and the plugging plate, and weld the contact position between the locking nut and the push rod to complete the plugging.

[0020] The beneficial effects of the present invention are:

[0021] In the present invention, in the initial stage, the blocking part is in a closed state and is inserted into the downcomer. As the blocking part moves downward in the downcomer, when it reaches below the bottom of the downcomer, the blocking part automatically switches from the closed state to the open state. Utilizing the water pressure of the groundwater, the blocking part closely adheres to the lower end of the downcomer, forming an effective seal. The seal depends not only on the physical contact between the blocking part and the downcomer, but also on the pressure difference generated by the water pressure, making the blocking part press more firmly on the downcomer. The greater the groundwater pressure, the better the sealing effect. In this way, after stopping the dewatering, the groundwater is not likely to gush out from the downcomer again. This enables the welding operation at the upper end of the downcomer to be in a dry environment, reducing the welding difficulty, improving the welding quality, and achieving a better sealing effect at the upper end of the downcomer. The welded and blocked part at the upper end of the downcomer is not prone to leakage, and there are fewer potential hazards after construction. In the future, the basement concrete floor slab is also not prone to water seepage, providing construction quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the present invention;

[0023] Figure 2 is a schematic structural diagram when the blocking part is in the first state;

[0024] Figure 3 is a schematic structural diagram when the blocking part is in the second state;

[0025] Figure 4 is a schematic structural diagram before the blocking part is inserted into the downcomer under the action of an external vertical force;

[0026] Figure 5 is a schematic structural diagram when the blocking part is inserted into the downcomer under the action of an external vertical force;

[0027] Figure 6 is a distribution diagram of the expansion diaphragm between the first head and the second head.

[0028] Reference numerals: 1 - blocking part, 101 - first head, 102 - second head, 2 - spring, 3 - expansion diaphragm, 4 - sealing ring, 5 - opening, 6 - second connecting column, 7 - downcomer, 8 - push rod, 9 - sealing rubber ring, 10 - blocking plate, 11 - locking nut, 12 - fixing block, 13 - first connecting column. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following further elaborates on the present invention in detail in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0030] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0031] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "arranged", "provided with", "installed", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Embodiment 1

[0033] A plugging device for a well point dewatering pipe 7 includes a plugging device body provided on the water connection path between the groundwater and the dewatering pipe 7. The plugging device body includes a plugging part 1 that can open and close. When the plugging part 1 is closed, it is in the first state, and when it is open, it is in the second state. The dewatering pipe 7 only allows the plugging part 1 in the first state to pass through. When the plugging part 1 is in the first state, it is inserted into the dewatering pipe 7 and moves downward. After the plugging part 1 moves downward outside the dewatering pipe 7, it automatically switches to the second state and tightly seals the lower end of the dewatering pipe 7 under the action of the groundwater pressure, so that the upper end of the dewatering pipe 7 is welded and plugged in a dry environment.

[0034] In this embodiment, the plugging part 1 is designed to have a structure that can open and close. As Figure 2 shown, when the plugging part 1 is in the closed state (the first state), its size is small enough to pass through the diameter of the dewatering pipe 7, which is convenient for inserting into the dewatering pipe 7 and generating relative movement with the dewatering pipe 7; as Figure 3 shown, when the plugging part 1 opens to the second state, its size will increase and it cannot pass through the inside of the dewatering pipe 7. As Figure 4 and Figure 5As shown, in the initial stage, by applying a downward vertical force to the plugging part 1, the plugging part 1 is in a closed state under the extrusion of the downcomer 7 and is inserted into the downcomer 7. As the plugging part 1 moves downward in the downcomer 7, the lower end of the closed plugging part 1 is in a conical shape, making it easier to insert into the downcomer 7 and move within the downcomer 7. When the plugging part 1 reaches the outside below the bottom of the downcomer 7, that is, when the outer circle of the upper end of the plugging part 1 disengages from the inside of the downcomer 7, the downcomer 7 releases the extrusion on the plugging part 1, and the plugging part 1 automatically switches from the closed state to the open state, and the application of the downward vertical force stops, as Figure 1 shown, using the water pressure of groundwater, the top of the plugging part 1 closely fits against the lower end of the downcomer 7 to form an effective seal. The seal depends not only on the physical contact between the plugging part 1 and the downcomer 7, but also on the pressure difference generated by the water pressure, making the plugging part 1 press more firmly on the downcomer 7. The greater the groundwater pressure, the better the plugging effect. In this way, after stopping the dewatering, groundwater is not likely to gush out from the inside of the downcomer 7 again, making the welding operation at the upper end of the downcomer 7 in a dry environment, reducing the welding difficulty, improving the welding quality, and also having a better sealing effect at the upper end of the downcomer 7. The welded position of the plugging part 1 at the upper end of the downcomer 7 is not likely to leak, and there are fewer potential hazards after construction. In the future, the basement concrete floor slab is also not likely to seep water, providing construction quality.

[0035] Furthermore, it also includes a push rod 8 connected to the top end of the plugging part 1. The length of the push rod 8 is greater than the length of the downcomer 7, and the diameter of the push rod 8 is smaller than the inner diameter of the downcomer 7. An external force acts on the upper end of the push rod 8 and drives the plugging part 1 to move downward along the length direction of the downcomer 7. After the plugging part 1 moves outside the downcomer 7, the external force stops.

[0036] Specifically, the push rod 8 is connected to the top end of the plugging part 1, playing a role in transmitting the external force. The push rod 8 is a solid rod. When an external force acts on the upper end of the push rod 8, it can effectively transmit this force to the plugging part 1 and drive the plugging part 1 to move downward along the length direction of the downcomer 7. The diameter of the push rod 8 is designed to be smaller than the inner diameter of the downcomer 7, so that it can serve as a guiding rod for the movement of the plugging part 1 within the downcomer 7, ensuring that the plugging part 1 can move smoothly and linearly. At the same time, the push rod 8 also provides the necessary support to prevent the plugging part 1 from deflecting or jamming during the movement. The length of the push rod 8 is designed to be greater than the length of the downcomer 7, so that even when the plugging part 1 is completely removed from the downcomer 7, a part of the push rod 8 still protrudes outside the upper end of the downcomer 7. In this way, the operator can conveniently operate the entire plugging device by controlling the protruding part of the push rod 8. Finally, the redundant push rod 8 can be cut off after the plugging is completed.

[0037] The operator applies an external force to the upper end of the push rod 8 in a certain way (such as manually, mechanically or hydraulically), driving the plugging part 1 to move downward. Under the action of the external force and the restrictive action of the downcomer 7, the plugging part 1 is in a closed state. As the push rod 8 moves downward, the plugging part 1 also moves accordingly until it completely moves out of the downcomer 7. When the plugging part 1 completely moves out of the downcomer 7, the operator stops applying the external force to the push rod 8. At this time, the plugging part 1 loses the restriction of the downcomer 7 and automatically opens, and closely fits against the lower end of the downcomer 7 under the action of the groundwater pressure to form an effective seal.

[0038] Furthermore, the lower end of the push rod 8 is integrally formed to constitute a first connecting column 13 and a second connecting column 6. There is an inverted V-shaped opening 5 between the first connecting column 13 and the second connecting column 6. The plugging part 1 includes a first head 101 and a second head 102 respectively corresponding to and connected to the first connecting column 13 and the second connecting column 6. A telescopic diaphragm 3 flush with the top surface of the plugging part 1 is provided between the first head 101 and the second head 102. Under the action of an external force, the first head 101 and the second head 102 can be closed, and after the external force is released, the first head 101 and the second head 102 open. A sealing ring 4 is provided on the top surface of the plugging part 1, and the inner diameter of the sealing ring 4 is larger than the diameter of the push rod 8.

[0039] Specifically, the lower end of the push rod 8 is integrally formed to constitute the first connecting column 13 and the second connecting column 6, ensuring a firm and reliable connection between the push rod 8 and the plugging part 1. An inverted V-shaped opening 5 is formed between the first connecting column 13 and the second connecting column 6. This opening 5 provides the necessary space for the opening and closing of the plugging part 1, and also enables the plugging part 1 to stably remain outside the downcomer 7 in the open state. The plugging part 1 includes a first head 101 and a second head 102 respectively corresponding to and connected to the first connecting column 13 and the second connecting column 6, ensuring that the plugging part 1 can closely fit on the push rod 8 and can quickly open or close when needed. A telescopic diaphragm 3 flush with the top surface of the plugging part 1 is provided between the first head 101 and the second head 102. This diaphragm can deform under the action of an external force, enabling the first head 101 and the second head 102 to close. When the external force is released, the telescopic diaphragm 3 returns to its original state, such as Figure 6As shown in the figure, the telescopic diaphragm 3 can prevent groundwater from flowing into the downcomer 7 through the gap between the two plugging heads and the opening 5. At the same time, under the action of groundwater pressure, the telescopic diaphragm 3 is squeezed upward by the water pressure and fits more closely to the bottom surface of the sealing ring 4, so that the sealing effect is better. A sealing ring 4 is provided on the top surface of the plugging part 1. The width of the sealing ring 4 is relatively wide and can cover the top surface of the plugging part 1. The inner diameter of this sealing ring 4 is larger than the diameter of the push rod 8, ensuring that the plugging part 1 can closely fit on the lower end of the downcomer 7 in the open state and under the action of water pressure, forming an effective seal. The sealing ring 4 plays a role in preventing groundwater from penetrating through the gap between the plugging part 1 and the downcomer 7.

[0040] Initial state: The plugging part 1 is in an open state, the telescopic diaphragm 3 is in its original state, and the sealing ring 4 is closely attached to the top surface of the plugging part 1.

[0041] External force action: When an external force acts on the upper end of the push rod 8, the downcomer 7 will have a limiting and squeezing effect on the first head 101 and the second head 102, causing the two heads to close. At this time, the push rod 8 will push the plugging part 1 downward. During this process, the telescopic diaphragm 3 is squeezed by the external force and deforms, causing the first head 101 and the second head 102 to gradually close.

[0042] Plugging process: When the plugging part 1 moves outside the downcomer 7, the external force stops acting. At this time, the two heads lose the limiting and squeezing of the downcomer 7, the first head 101 and the second head 102 open, the telescopic diaphragm 3 resets. At the same time, the groundwater pressure acts on the plugging part 1 and the telescopic diaphragm 3. The telescopic diaphragm 3 closely fits on the bottom surface of the sealing ring 4 under the action of groundwater pressure. At the same time, the sealing ring 4 closely fits on the lower end of the downcomer 7 under the action of groundwater pressure, forming an effective seal.

[0043] Furthermore, a spring 2 is provided between the first head 101 and the second head 102, and the two ends of the spring 2 act on the opposite side walls of the first head 101 and the second head 102 respectively.

[0044] Specifically, the spring 2 is arranged between the first head 101 and the second head 102, and its two ends act on the opposite side walls of the first head 101 and the second head 102 respectively. When an external force acts on the push rod 8 to move the plugging part 1 outside the downcomer 7 and is released, the elastic force of the spring 2 will automatically assist in pushing the first head 101 and the second head 102 to open, so as to better realize the automatic opening function of the plugging part 1. The stiffness and pre-tightening force of the spring 2 can be adjusted according to actual needs. By selecting the appropriate stiffness and pre-tightening force of the spring 2, it can be ensured that the plugging part 1 has sufficient force when opening and closely fits on the lower end of the downcomer 7, forming an effective seal.

[0045] In the initial state, the blocking part 1 is in an open state, and the spring 2 is in a pre-tightened state. At this time, the first head 101 and the second head 102 maintain a certain opening angle under the elastic force of the spring 2. When an external force acts on the upper end of the push rod 8, the push rod 8 pushes the blocking part 1 to move downward. During this process, the spring 2 is compressed, and the first head 101 and the second head 102 gradually close. When the blocking part 1 moves outside the downcomer 7, the external force stops acting. At this time, the spring 2 quickly returns to its original state, pushing the first head 101 and the second head 102 to open. At the same time, the sealing ring 4 of the blocking part 1 closely adheres to the lower end of the downcomer 7 under the action of the groundwater pressure, forming an effective seal.

[0046] Further, a blocking plate 10 is sleeved on the push rod 8. The outer wall of the push rod 8 is provided with an external thread, and a locking nut 11 is threadedly connected to the push rod 8 above the blocking plate 10. Rotating the locking nut 11 causes the push rod 8 to drive the blocking part 1 to generate a relative upward displacement with respect to the downcomer 7 and squeeze the sealing ring 4.

[0047] Specifically, the blocking plate 10 is a steel plate. The blocking plate 10 is sleeved on the push rod 8 and is located above the blocking part 1. The blocking plate 10 is the last plate welded and sealed to the top end of the downcomer 7. The outer wall of the push rod 8 is provided with an external thread, which provides the necessary thread fit for the connection of the locking nut 11. By rotating the locking nut 11, the pressing degree between the blocking part 1 and the downcomer 7 can be adjusted. When the locking nut 11 is screwed, the push rod 8 will generate an upward displacement, thereby driving the blocking part 1 to generate a relative upward displacement with respect to the downcomer 7. This displacement process will squeeze the sealing ring 4 on the blocking part 1, making it more closely adhere to the lower end of the downcomer 7, forming a more effective seal.

[0048] Further, a fixing block 12 adapted to the inner diameter of the downcomer 7 is provided on the bottom surface of the blocking plate 10. A sealing rubber ring 9 is circumferentially embedded in the fixing block 12, and the sealing rubber ring 9 is pressed between the side wall of the fixing block 12 and the inner wall of the downcomer 7.

[0049] Specifically, a fixing block 12 adapted to the inner diameter of the downcomer 7 is provided on the bottom surface of the blocking plate 10. A sealing rubber ring 9 is circumferentially embedded in the fixing block 12. This sealing rubber ring 9 is made of an elastic material and has certain elasticity and sealing performance. When the fixing block 12 is inserted into the downcomer 7, the sealing rubber ring 9 will be pressed between the side wall of the fixing block 12 and the inner wall of the downcomer 7. This pressing process causes the sealing rubber ring 9 to deform, thereby filling the tiny gap between the fixing block 12 and the inner wall of the downcomer 7, forming a tighter seal.

[0050] Further, after the locking nut 11 is rotated in place, the blocking plate 10 is circumferentially welded to the top end of the downcomer 7, and the push rod 8 is welded between the blocking plate 10 and the locking nut 11.

[0051] Specifically, when the locking nut 11 is rotated into place, the sealing plate 10 is circumferentially welded to the top end of the downcomer 7, and the push rod 8 is also welded to the sealing plate 10 and the locking nut 11. The sealing portion 1 has effectively sealed the water inlet at the lower end of the downcomer 7, so that no groundwater will gush out from the upper end of the downcomer 7, and thus it can be in a dry environment. At this time, the sealing plate 10 is circumferentially welded to the upper end of the downcomer 7, and the contact positions of the locking nut 11 with the sealing plate 10 and the push rod 8 are welded to achieve the welding and plugging of the upper end of the downcomer 7. Even if there is groundwater in the downcomer 7 later, it will not gush out from the upper end of the downcomer 7. The dry welding environment reduces the welding difficulty, improves the welding quality, and also has a better sealing effect on the upper end of the downcomer 7. The welding and plugging part 1 at the upper end of the downcomer 7 is not prone to leakage, and there are fewer potential hazards after construction. In the future, the basement concrete floor slab is not prone to water seepage, which improves the construction quality.

[0052] Embodiment 2

[0053] A plugging method includes the following steps:

[0054] Step S1: Before plugging, if there is a fine sand filter layer in the downcomer 7, it is necessary to clean the fine sand filter layer first. If there is no fine sand filter layer, there is no need to clean.

[0055] Step S2: Place the lower end of the plugging portion 1 on the upper end of the downcomer 7, and place the sealing ring 4 on the plugging portion 1 after passing through the push rod 8. At this time, the first head 101 and the second head 102 are in the second state. Apply a downward vertical force to the push rod 8 through the hydraulic cylinder, so that the downcomer 7 exerts pressure on the first head 101 and the second head 102. The first head 101 and the second head 102 can be inserted into the downcomer 7 in the first state and move downward along the length direction of the downcomer 7 under the action of the vertical force until the plugging portion 1 moves to the outside of the lower end of the downcomer 7. Then, retract the push rod 8 upward, so that the sealing ring 4 contacts the lower end of the downcomer 7, and under the action of the groundwater pressure, the plugging portion 1 is pressed tightly against the lower end of the downcomer 7, making the welding and plugging at the upper end of the downcomer 7 in a dry environment;

[0056] Step S4: Then, put the sealing plate 10 on the push rod 8, the fixing block 12 with the sealing rubber ring 9 is embedded in the downcomer 7, then thread the locking nut 11 onto the push rod 8, remove the hydraulic cylinder, and then clamp the push rod 8 with a tool to prevent the push rod 8 from rotating when the locking nut 11 is screwed. Then, use a tool to screw the locking nut 11 and drive the push rod 8 to generate an upward relative displacement, thereby driving the plugging portion 1 to move upward, so that the sealing ring 4 is further pressed tightly between the lower end of the downcomer 7 and the top end of the plugging portion 1;

[0057] Step S5: After the locking nut 11 is screwed in place, weld the contact positions of the plugging plate 10 with the downcomer 7, the contact positions of the locking nut 11 with the plugging plate 10, and the contact positions of the locking nut 11 with the push rod 8 to complete the plugging.

[0058] In this embodiment, it is a method for plugging the downcomer 7. Specifically, before plugging, if there is a fine sand filter layer in the downcomer 7, the fine sand filter layer needs to be cleaned first. Specifically, a sharp steel bar can be inserted into the downcomer 7 and forcefully pushed downward to poke the fine sand filter layer into the groundwater. If there is no fine sand filter layer, there is no need to clean it.

[0059] As Figure 4 shown, then place the lower end of the plugging part 1 on the upper end of the downcomer 7, and place the sealing ring 4 on the plugging part 1 after passing through the push rod 8. At this time, the first head 101 and the second head 102 are in the second state. Apply a downward vertical force to the push rod 8 through a hydraulic cylinder (not shown in the figure). The telescopic end of the hydraulic cylinder presses downward on the upper end of the push rod 8. The hydraulic cylinder can be fixed on a bracket, and the bracket is fixed on the ground. Or a vertical force can be directly applied manually. As Figure 5 shown, based on the vertical force and combined with the limiting extrusion of the downcomer 7 on the first head 101 and the second head 102, the first head 101 and the second head 102 are in the first state. Continuing to apply the vertical force in this way enables the plugging part 1 to be inserted into the downcomer 7 and move downward along the length direction of the downcomer 7 under the action of the vertical force until the plugging part 1 moves to the outside of the lower end of the downcomer 7. The push rod 8 can be manually retracted vertically upward to ensure that the plugging part 1 is completely located outside the lower end of the downcomer 7. As Figure 1 shown, under the action of the groundwater pressure, the plugging part 1 is pressed tightly against the lower end of the downcomer 7, and the sealing ring 4 is pressed tightly. At the same time, the water pressure will also press the expansion diaphragm 3 against the bottom surface of the sealing ring 4, thus effectively isolating the groundwater and preventing the groundwater from flowing into the downcomer 7.

[0060] Then, put the plugging plate 10 on the push rod 8, insert the fixing block 12 with the sealing rubber ring 9 into the downcomer 7, then thread the locking nut 11 onto the push rod 8, remove the hydraulic cylinder, and then clamp the upper end of the push rod 8 with a pipe wrench or other tools to prevent the push rod 8 from rotating when screwing the locking nut 11. Then, use a wrench or other tools to screw the locking nut 11 and drive the push rod 8 to generate an upward relative displacement, thereby driving the plugging part 1 to move upward. This displacement process will squeeze the sealing ring 4 on the plugging part 1 to make it fit more tightly against the lower end of the downcomer 7, forming a more effective seal. Finally, after the locking nut 11 is screwed in place, weld the contact positions of the plugging plate 10 with the downcomer 7, the contact positions of the locking nut 11 with the plugging plate 10, and the contact positions of the locking nut 11 with the push rod 8 to complete the welding and plugging of the upper end of the downcomer 7.

[0061] As described above, it is only the preferred embodiment of the present invention, and there is no restriction on the present invention in any form. According to the technical essence of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A plugging device that facilitates welding of the upper end of a well point downpipe, characterized in that: The invention comprises a plugging device body arranged on a waterway connecting groundwater and a downcomer (7), the plugging device body comprising a plugging portion (1) capable of opening and closing, the plugging portion (1) being in a first state when closed and in a second state when opened, the downcomer (7) only allowing the plugging portion (1) in the first state to pass through, the plugging portion (1) being inserted into the downcomer (7) and moving downward when in the first state, the plugging portion (1) automatically switches to the second state after moving downward to the outside of the downcomer (7) and compressing and sealing the lower end of the downcomer (7) under the action of groundwater pressure so that the welded plugging at the upper end of the downcomer (7) is in a dry environment.

2. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 1, characterized in that: It also includes a push rod (8) connected to the top end of the blocking portion (1), the length of the push rod (8) is greater than the length of the downpipe (7), the diameter of the push rod (8) is smaller than the inner diameter of the downpipe (7), an external force acts on the upper end of the push rod (8) and drives the blocking portion (1) to move downward along the length direction of the downpipe (7), and the external force stops after the blocking portion (1) moves outside the downpipe (7).

3. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 2, characterized in that: The lower end of the push rod (8) is integrally formed to form a first connecting column (13) and a second connecting column (6), and an inverted V-shaped opening (5) is provided between the first connecting column (13) and the second connecting column (6). The sealing portion (1) comprises a first head (101) and a second head (102) respectively connected to the first connecting column (13) and the second connecting column (6). A telescopic diaphragm (3) flush with the top surface of the sealing portion (1) is provided between the first head (101) and the second head (102). Under the action of external force, the first head (101) and the second head (102) can be closed, and after the external force is released, the first head (101) and the second head (102) open. A sealing ring (4) is provided on the top surface of the sealing portion (1), and the inner diameter of the sealing ring (4) is greater than the diameter of the push rod (8).

4. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 3, characterized in that: A spring (2) is provided between the first seal head (101) and the second seal head (102), and two ends of the spring (2) act on opposite side walls of the first seal head (101) and the second seal head (102) respectively.

5. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 3, characterized in that: The push rod (8) is sleeved with a blocking plate (10), the outer wall of the push rod (8) is provided with an external thread, and the push rod (8) is threadedly connected with a locking nut (11) located above the blocking plate (10). When the locking nut (11) is rotated, the push rod (8) drives the blocking part (1) to move upward relative to the downcomer (7) and squeeze the sealing ring (4).

6. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 5, characterized in that: The bottom surface of the blocking plate (10) is provided with a fixing block (12) adapted to the inner diameter of the downcomer (7), and a sealing rubber ring (9) is embedded in the fixing block (12) in the circumferential direction, and the sealing rubber ring (9) is pressed tightly between the side wall of the fixing block (12) and the inner wall of the downcomer (7).

7. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 5, characterized in that: After the locking nut (11) is rotated into place, the sealing plate (10) is circumferentially welded to the top end of the downcomer (7), and the push rod (8) is welded to the sealing plate (10) and the locking nut (11).

8. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 5, characterized in that: The push rod (8) is a solid rod.

9. A plugging device for facilitating welding of the upper end of a well point downpipe according to claim 1, characterized in that: The closing lower end of the blocking portion (1) is in a cone shape.

10. A plugging method for a plugging device for facilitating welding of the upper end of a well point downpipe as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: Step S1: before plugging, if a fine sand filter layer is provided in the downcomer (7), the fine sand filter layer needs to be cleaned out first; if no fine sand filter layer is provided, it does not need to be cleaned out; Step S2: placing the lower end of the plugging portion (1) on the upper end of the downcomer (7), and placing the sealing ring (4) on the plugging portion (1) after passing through the push rod (8). At this time, the first end cap and the second end cap are in the second state, and a downward vertical force is applied to the push rod (8) by the hydraulic cylinder, so that the downcomer (7) squeezes the first end cap (101) and the second end cap (102). The first end cap (101) and the second end cap (102) are in the first state and can be inserted into the downcomer (7), and move downward along the length direction of the downcomer (7) under the action of the vertical force until the plugging portion (1) moves to the outside of the lower end of the downcomer (7), and then the push rod (8) is retracted upward, so that the sealing ring (4) contacts the lower end of the downcomer (7), and the plugging portion (1) is pressed against the lower end of the downcomer (7) under the action of the groundwater pressure, so that the welding plugging at the upper end of the downcomer (7) is in a dry environment; Step S4: Then, the blocking plate (10) is sleeved on the push rod (8), and the fixing block (12) with the sealing rubber ring (9) is embedded in the downcomer (7). Then, the locking nut (11) is threadedly connected to the push rod (8), and the hydraulic cylinder is removed. Then, the push rod (8) is clamped by a tool to prevent the push rod (8) from rotating when the locking nut (11) is screwed. Then, the locking nut (11) is screwed by a tool to drive the push rod (8) to produce an upward relative displacement, thereby driving the blocking part (1) to move upward, so that the sealing ring (4) is further pressed between the lower end of the downcomer (7) and the top of the blocking part (1); Step S5: After the locking nut (11) is screwed into place, the contact position between the sealing plate (10) and the downcomer (7) is welded, the contact position between the locking nut (11) and the sealing plate (10) is welded, and the contact position between the locking nut (11) and the push rod (8) is welded to complete the sealing.

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