Shock-absorbing damper for packer and chemical injection device equipped therewith

Abstract

In ground improvement using packers, this enables precise injection of chemical solutions into the correct locations and prevents buckling of chemical solution hoses and air hoses. [Solution] The packer comprises an impact-absorbing damper 31 and a packer to which it is connected. The damper includes an outer tube 32 to which a chemical supply hose is connected, a rod 34 inserted into the outer tube so as to be movable in the longitudinal direction of the outer tube with a portion of its lower end protruding from the lower end of the outer tube and connected to the packer, and a compression spring 41 located inside the outer tube on the upper end side of the rod. The packer includes a head, an upper packer section connected to the lower side of the head, a nozzle section with a chemical discharge port connected to the lower side of the upper packer, and a lower packer section connected to the lower side of the nozzle section. The packer includes a chemical transport path for transporting the chemical to the chemical discharge port and an air transport path for transporting a pressure medium to the inner circumference of the upper packer section and the lower packer section.

Description

Technical Field

[0001] The present invention relates to a shock absorption damper for a packer used for infiltrating a chemical solution such as cement milk into the ground through a sleeve pipe inserted into a bored hole formed in the ground, and a chemical solution injection device provided with the same. More specifically, in a construction method in which a closed space is formed in a sleeve pipe by expanding a plurality of expansion parts provided in a packer and a chemical solution is discharged into this closed space to improve the ground, when the pressure below the closed space becomes high pressure and the injection of the chemical solution is completed and the expansion of the expansion part is released, the present invention relates to a shock absorption damper for absorbing the shock received by the packer in the direction of protruding above the ground and a chemical solution injection device provided with the same.

Background Art

[0002] As is well known, when constructing a dam or a large structure, it is necessary to improve and strengthen the ground. Conventionally, as a method, while discharging a chemical solution such as cement milk into a bored hole formed in the ground and a sleeve pipe inserted therein, this chemical solution is infiltrated into the ground while being pressure-injected into the ground through cracks or the like on the side wall of the bored hole to strengthen the ground.

[0003] And at this time, conventionally, a chemical solution injection device called a packer has been used as a device for sealing a specific space in a bored hole and a sleeve pipe inserted therein to form a closed space and injecting a chemical solution into this closed space.

[0004] That is, this packer is provided with expansion parts at two locations, upper and lower, at intervals in the longitudinal direction, which expand toward the outer peripheral side when receiving fluid pressure and return to the original shape when the pressure is released. A chemical solution discharge port is provided between these expansion parts.

[0005] When using this packer for ground improvement, the packer is inserted into a sleeve pipe that has been inserted into a borehole and lowered to a predetermined depth. In this state, the expansion part is inflated with a pressurized fluid such as air, and the expansion part pushes the inner wall of the sleeve pipe outward, thereby fixing the position of the packer inside the sleeve pipe. Furthermore, the space between the expanded expansion parts inside the sleeve pipe is sealed to form a closed space. Then, the chemical solution is discharged into the sleeve pipe at high pressure from the chemical solution discharge port, filling the closed space with the chemical solution, and then the chemical solution is injected at even higher pressure. In this way, the chemical solution can be injected into the ground and permeate through the injection hole formed in the sleeve pipe, thereby enabling ground improvement.

[0006] After the injection of the chemical solution into the ground is complete, the air is released to deinflate the expansion section, the packer is raised a certain distance, and then the same chemical solution such as cement grout is injected into the ground again at that position using the same method as described above. This makes it possible to perform ground improvement even in soft ground.

[0007] As mentioned earlier, when injecting chemicals into the ground using a packer, the packer's position within the sleeve pipe is fixed by expanding the expansion section inside the sleeve pipe, and a closed space is formed between the expansion sections. After filling this closed space with chemicals, more chemicals are injected, releasing them through the circular holes and check valves formed in the sleeve pipe. However, in order to penetrate the chemicals into the ground, the injection of chemicals must be done at high pressure. Therefore, when releasing the chemicals, some may leak from the expansion section located at the bottom of the packer to the lower side of the closed space. As a result, the pressure of air, etc., gradually increases in the lower side of the closed space inside the sleeve pipe, and this increased pressure pushes the packer strongly towards the ground.

[0008] Consequently, after the injection of the chemical solution is complete, if the expansion of the expansion section is released and the packer is released from its fixation inside the sleeve pipe, the packer will be pushed by the high pressure at the bottom of the enclosed space and will rapidly rise towards the ground. In this case, the rapid rise of the packer will cause the chemical solution supply hose that supplies the chemical solution to the packer, and the air hose that supplies pressurized fluid such as air to expand the expansion section, to buckle due to the impact of the rapidly rising packer, rendering them unusable.

[0009] To this end, the inventors have previously proposed a chemical injection device that includes an air release tube inside the packer for releasing air from below the confined space, thereby reducing the pressure by releasing the air from below the confined space through this air release tube. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2020-59985 [Overview of the project] [Problems that the invention aims to solve]

[0011] However, in chemical injection devices equipped with an air release tube inside the packer to release high-pressure air from below the enclosed space, it was pointed out that special measures would need to be taken to the packer in order to accommodate the air release tube, which would increase the manufacturing cost of the chemical injection device.

[0012] Therefore, the present invention aims to provide an impact-absorbing damper and a chemical injection device equipped therewith that can prevent buckling of the chemical supply hose and air hose even when the packer rises rapidly due to high-pressure air below the enclosed space by releasing the expansion of the expansion section after the chemical injection is completed, without requiring any special processing of the packer in ground improvement using a packer. [Means for solving the problem]

[0013] The shock-absorbing damper for packers of the present invention is An impact-absorbing damper connected to a packer used for injecting a soil improvement chemical solution into the ground, It is a hollow, elongated cylindrical outer tube, with a hollow chemical hose adapter attached to its upper end, A rod is hollow and long in shape, and is inserted into the outer tube such that a portion of its lower end protrudes from the lower end of the outer tube, allowing it to move freely in the longitudinal direction of the outer tube, and a hollow packer connecting adapter is attached to its lower end. The outer tube comprises an elastic means positioned between the chemical hose connecting adapter and the upper end of the rod, The rod is designed to retract into the outer tube when subjected to pressure in the direction of insertion into the outer tube, and to return to its original position when the pressure is released due to the biasing force of the elastic means. This system is characterized by the fact that the chemical solution supply hose is connected to a chemical solution hose connecting adapter, and the packer is connected to a packer connecting adapter, thereby enabling the chemical solution supplied via the chemical solution supply hose to be supplied to the packer through the inside of the outer tube and the inside of the rod.

[0014] The drug injection device of the present invention is A chemical injection device comprising the aforementioned shock-absorbing damper and a packer connected to the shock-absorbing damper, The aforementioned packer, The head and, An upper packer section connected to the underside of the head, having an expandable section that expands outward when subjected to fluid pressure toward the outer circumference and returns to its original shape when the pressure is released, A nozzle section connected to the lower side of the upper packer, which has a chemical discharge port for releasing the chemical solution, The nozzle portion is connected to the lower side of the nozzle portion and has an expandable portion that expands outward when subjected to fluid pressure toward the outer circumference and returns to its original shape when the pressure is released, The upper end has an opening in the head, and the lower end has a chemical transport path that leads to the chemical discharge port, The upper end has an opening in the head, and the lower end extends to the inner circumference of the expansion section of the lower packer, and is equipped with a pressure fluid transport path that extends to the inner circumference of the expansion section of the upper packer and the inner circumference of the expansion section of the lower packer, The head is characterized in that the shock-absorbing damper is connected to it. [Effects of the Invention]

[0015] The shock-absorbing damper for packers of the present invention comprises a hollow, elongated cylindrical outer tube to which a chemical hose is connected via a hollow chemical hose connecting adapter attached to its upper end, and a hollow, elongated cylindrical rod to which a packer is connected, with a portion of the lower end protruding from the outer tube and inserted into the outer tube. An elastic means is arranged between the chemical hose connecting adapter and the upper end of the rod within the outer tube, and the rod retracts into the outer tube when pressure is applied in the direction of insertion into the outer tube, and returns to its original position when the pressure is released. Therefore, after the injection of the chemical solution into the ground is completed, the expansion of the expansion section is released, and the fixing of the packer inside the sleeve pipe is released. As a result, if the packer is pushed by the high pressure on the lower side of the enclosed space and rises rapidly toward the ground, only the rod to which the packer is connected will retract into the outer pipe. In other words, the impact of the packer's sudden rise is absorbed by the packer's shock-absorbing damper of the present invention, so the chemical solution supply hose and air hose are not subjected to the impact of the packer's sudden rise, and therefore the chemical solution supply hose and air hose do not buckle.

[0016] Therefore, by connecting the shock-absorbing damper of the present invention to a packer, in ground improvement using a packer, it is possible to prevent buckling of the chemical supply hose and air hose even if the packer rises rapidly due to high-pressure air below the enclosed space by releasing the expansion of the expansion section after the chemical injection is completed, without performing any special processing on the packer. [Brief explanation of the drawing]

[0017] [Figure 1] This is a diagram showing an overview of an embodiment of the shock absorber of the present invention. [Figure 2] This shows a longitudinal structure showing the configuration of an embodiment of the shock absorber of the present invention. [Figure 3] This is a diagram for explaining the piston packing used in an embodiment of the shock absorber of the present invention. [Figure 4] This is a diagram for explaining the packer in an embodiment of the chemical liquid injection device of the present invention, and shows a part of the longitudinal structure. [Figure 5] This is a diagram for explaining the packer in an embodiment of the chemical liquid injection device of the present invention, and shows a part of the longitudinal structure.

Embodiments for Carrying Out the Invention

[0018] The shock absorber for the packer of the present invention is a shock absorber connected to a packer used for injecting a chemical liquid for ground improvement into the ground. It is hollow and long cylindrical, and has an outer pipe with a hollow chemical liquid hose connection adapter mounted at the upper end.

[0019] And a rod is inserted into this outer pipe. This rod is hollow and long cylindrical, and a part on the lower end side protrudes from the lower end of the outer pipe and is inserted movably in the longitudinal direction of the outer pipe. A hollow packer connection adapter is mounted at the lower end.

[0020] Furthermore, inside the outer pipe, a compression spring as elastic means is arranged between the chemical liquid hose connection adapter and the upper end of the rod.

[0021] And thereby, the rod receives pressure in the direction of being inserted into the outer pipe, retreats into the outer pipe while compressing the compression spring, and returns to the original position by the biasing force of the compression spring when the pressure is released.

[0022] Furthermore, the shock-absorbing damper of the present invention connects the chemical supply hose to a chemical hose connecting adapter and connects the packer to a packer connecting adapter, thereby enabling the chemical solution supplied via the chemical supply hose to be supplied to the packer through the inside of the outer tube and the inside of the rod.

[0023] Here, the rod may be equipped with a hollow piston at its upper end. In this case, the piston has a cylindrical body, an upper enlarged portion formed on the upper end of the body with an outer diameter slightly smaller than the inner diameter of the outer tube, and a lower enlarged portion formed near the middle of the body when viewed in the vertical direction, with an outer diameter equal to the inner diameter of the outer tube. A piston packing is preferably placed between the upper and lower enlarged portions, with a gap formed between them. Furthermore, the piston packing may have an outer lip portion, an inner lip portion, and a recess located between the outer and inner lip portions on the surface facing the upper enlarged portion.

[0024] Next, the chemical injection device of the present invention is composed of the aforementioned shock-absorbing damper for packers and a packer to which this shock-absorbing damper for packers is connected.

[0025] The packer has a head, to which the shock-absorbing damper is connected. An upper packer section is connected to the lower side of the head, and the upper packer section has an expandable part that expands outward when subjected to fluid pressure toward the outer circumference, and returns to its original shape when the pressure is released.

[0026] Furthermore, a nozzle section equipped with a chemical discharge port for releasing the chemical solution is connected to the lower side of the upper packer, and a lower packer section is connected to the lower side of the nozzle section. This lower packer section, like the upper packer section mentioned above, has an expandable section that expands outward when subjected to fluid pressure toward the outer circumference and returns to its original shape when the pressure is released.

[0027] Furthermore, the packer is equipped with a chemical transport channel for transporting the chemical to the chemical discharge port of the nozzle, and a pressurized fluid transport channel for supplying pressurized fluid to the inner circumference of the expansion section of the upper and lower packer sections.

[0028] The chemical transport path has an opening at its upper end in the head and its lower end leads to the chemical discharge port of the nozzle. The pressurized fluid transport path has an opening at its upper end in the head and its lower end reaches the inner circumference of the expansion section of the lower packer, and further connects to the inner circumference of the expansion section of the upper packer and the inner circumference of the expansion section of the lower packer.

[0029] Here, the head has a head body having a chemical transport passage with an opening at the end of the head, and the shock-absorbing damper is connected to the upper part of this head body. Furthermore, a mantle having a chemical transport passage continuous with the chemical transport passage of the head body is connected to the lower part of the head body. When connecting the upper packer part to the lower side of the head, it is preferable that the mantle is connected to the nozzle part in such a way that it penetrates the upper packer part and the chemical transport passage of the mantle leads to the chemical discharge port. In this way, by connecting the upper packer part to the lower side of the head, it is possible to provide a chemical transport passage. [Examples]

[0030] An embodiment of the impact-absorbing damper for packers of the present invention (hereinafter simply referred to as "impact-absorbing damper") will be described with reference to the figures. Figure 1 shows the general external shape of the impact-absorbing damper of this embodiment, and Figure 2 is a partial cross-sectional view showing the configuration of the impact-absorbing damper of this embodiment, with an enlarged view of a part of the structure along the longitudinal direction.

[0031] In the figure, 31 is the shock-absorbing damper of this embodiment, and the shock-absorbing damper 31 of this embodiment has an outer tube. That is, in the figure, 32 is the outer tube, and the outer tube 32 is hollow and has a long cylindrical shape with both ends open.

[0032] Furthermore, a chemical hose connection adapter 33 is attached to the upper end (upper side in the diagram), to which a chemical supply hose is connected when in use. The chemical hose connection adapter 33 is hollow, and by connecting the chemical supply hose, the chemical can be supplied into the outer tube 32.

[0033] Next, in the figure, 34 is a rod. That is, in this embodiment, the shock-absorbing damper 31 has a rod 34, which is a long, hollow cylindrical rod and is inserted into the outer tube 32, leaving a portion of the lower side (lower side in the figure) exposed. In other words, the rod 34 is inserted into the outer tube 32 with the lower portion exposed, and furthermore, the rod 34 is movable in the longitudinal direction of the outer tube 32.

[0034] A hollow piston 35 is attached to the upper end of the rod 34, and a hollow packer connecting adapter 40 is attached to the lower end of the rod 34, and the packer connecting adapter 40 is connected to the packer. Therefore, the chemical supplied from the chemical supply hose is supplied into the outer pipe 32 via the chemical hose connecting adapter 33, then supplied into the rod 34 via the piston 35, and then supplied to the packer via the packer connecting adapter 40.

[0035] In the figure, 39 is a rod guide, which is a hollow cylindrical shape and is attached to the lower end of the outer tube 32 to facilitate the smooth movement of the rod 34. Specifically, the outer diameter of the rod 34 is smaller than the inner diameter of the outer tube 32, creating a small gap between them. On the other hand, the inner diameter of the rod guide 39 is approximately the same as the outer diameter of the rod 34, allowing the rod 34 to slide against the rod guide 39. As shown in the figure, the lower outer diameter of the rod guide 39 is the same as the outer diameter of the outer tube 32, making them flush. However, the upper outer diameter is reduced by machining the outer circumference to thin the wall thickness, allowing it to be inserted into the outer tube 32.

[0036] Next, the piston 35 has a cylindrical main body 36 and enlarged portions formed by enlarging the outer diameter of the main body 36 at any two locations. In this embodiment, the enlarged portions consist of an upper enlarged portion 37a formed on the upper end side of the main body 36 and a lower enlarged portion 37b formed near the middle portion when viewed in the vertical direction of the main body 36. The outer diameter of the lower enlarged portion 37b is the same as the inner diameter of the outer tube 32, and the outer diameter of the upper enlarged portion 37a is slightly smaller than the inner diameter of the outer tube 32. Furthermore, the piston 35 is connected to the upper part of the rod 34 by inserting the part of the piston 35 below the lower enlarged portion 37b of the main body portion 36 into the rod 34, and the upper end of the rod 34 abuts against the lower end surface of the lower enlarged portion 37b, so that when the rod 34 moves in the direction of being inserted into the outer tube 32, the piston 35 also moves toward the upper end of the outer tube 32 together with the rod 34, and at that time the outer circumference of the lower enlarged portion 37b slides against the inner wall of the outer tube 32.

[0037] Furthermore, a space of a predetermined distance is formed below the lower enlarged portion 37b of the piston 35. When the rod 34 moves beyond the predetermined distance towards the lower end, the lower enlarged portion 37b of the piston 35 collides with the upper end of the rod guide 39, preventing the rod 34 from flying out of the outer tube 32.

[0038] Next, in the figure, 38 is a piston packing positioned between the upper enlarged portion 37a and the lower enlarged portion 37b. This piston packing 38 is used to prevent the chemical solution supplied into the outer tube 32 from leaking out onto the outer circumference of the rod 34 through the outer circumference of the piston 35.

[0039] Now, referring to Figure 3, the piston packing 38 is shown in a longitudinal cross-sectional view. This piston packing 38 is disc-shaped with a through hole on its inner circumference through which the piston 35 passes. The inner circumference of the piston packing 38 has a diameter that allows it to clamp the portion of the piston 35 between the upper enlarged portion 37a and the lower enlarged portion 37b. The outer diameter of the piston packing 38 is such that it can slide on the inner circumference of the outer tube 32.

[0040] Next, in the figure, 42 is the lip portion. That is, in this embodiment, the piston packing 38 has a lip portion 42 formed around its entire circumference on the surface facing the upper enlarged portion 37a. In Figure 3, 42 indicates the lip portion, which has an outer lip portion 43 formed by the outer edge portion projecting upward around its entire circumference, and an inner lip portion 44 formed by the inner edge portion projecting upward around its entire circumference. Between the outer lip portion 43 and the inner lip portion 44 is a recessed area 45 that is recessed downward around its entire circumference. In this embodiment, the presence of the lip portion 42 reliably prevents the liquid supplied into the outer tube 32 from leaking out onto the outer circumference of the rod 34.

[0041] To explain this relationship, as is clear from Figure 2, in this embodiment, a small gap is formed between the upper end of the piston packing 38 and the lower end of the lower enlarged portion 37b. Therefore, as mentioned above, the outer diameter of the upper enlarged portion 7a is slightly smaller than the inner diameter of the outer tube 32, so when chemical solution is supplied into the outer tube 32 from the chemical solution supply hose, a portion of the chemical solution supplied into the outer tube 32 passes between the outer circumference of the upper enlarged portion 37a and the inner wall of the outer tube 32 and is supplied into the gap formed between the upper end of the piston packing 38 and the lower end of the lower enlarged portion 37b. As the supply of chemical solution into the outer tube 32 continues, the chemical solution supplied into the gap formed between the upper end of the piston packing 38 and the lower end of the lower enlarged portion 37b is guided into the recess 45 between the outer lip portion 43 and the inner lip portion 44. As a result, the outer lip portion 43 is pressed by the chemical solution guided into the recess 45 and opens outwards. As a result, the outer lip portion 43 adheres tightly to the inner circumference of the outer tube 32, creating a sealing function between it and the inner wall of the outer tube 32, which reliably prevents the chemical solution supplied into the outer tube 32 from leaking out onto the outer circumference of the rod 34.

[0042] Next, in Figure 2, 41 is a compression spring as an elastic means. That is, in this embodiment, the shock-absorbing damper 31 has a compression spring 41 positioned inside the outer tube 32 between the piston 35 and the chemical hose connecting adapter 33. Specifically, the upper end of the compression spring 41 is connected to the chemical hose connecting adapter 33, and the lower end is connected to the piston 35. As a result, when the rod 34 receives pressure in the direction of insertion into the outer tube 32, it retracts upward inside the outer tube 32 in opposition to the biasing force of the compression spring 41, and when the pressure is released, it returns to its original position due to the biasing force of the compression spring 41. Therefore, under normal circumstances, the compression spring 41 is not compressed.

[0043] Next, the operation of the shock-absorbing damper 31 of this embodiment, which is configured in this way, will be explained. The shock-absorbing damper 31 of this embodiment is used by being interposed between a packer and a chemical supply hose that supplies chemical to the packer when performing ground improvement by injecting chemical into the ground using a packer. That is, with the compression spring 41 in an uncompressed state, the packer connecting adapter 40 is connected to the packer, and the chemical supply hose is connected to the chemical hose connecting adapter 33. In this state, the packer is inserted into the sleeve pipe inserted into the borehole, and after the packer has been lowered to a predetermined depth, the expansion part of the packer is expanded to fix the position of the packer inside the sleeve pipe and to form a closed space between the expansion parts inside the sleeve pipe. In this state, the chemical solution is supplied from the chemical solution supply hose to the outer pipe 32 via the chemical solution hose connection adapter 33. This chemical solution is then supplied to the packer via the piston 35, rod 34, and packer connection adapter 40. The chemical solution is then discharged at high pressure into the sleeve pipe from the chemical solution discharge port, and injected into the ground through the injection hole formed in the sleeve pipe to perform ground improvement.

[0044] Then, after the injection of the chemical solution into the ground is completed, the expansion of the expansion section is released and the fixing of the packer inside the sleeve pipe is released, causing the packer to be pushed by the high pressure on the lower side of the closed space and rise rapidly toward the ground. In this case, the shock-absorbing damper 31 of this embodiment is positioned between the packer and the chemical solution supply hose that supplies the chemical solution to the packer, with the rod 34 connected to the packer via the packer connecting adapter 40 and the chemical solution supply hose connected via the chemical solution hose connecting adapter 33. Furthermore, when the rod 34 receives pressure in the direction of insertion into the outer pipe 32, it retracts upward into the outer pipe 32 in opposition to the biasing force of the compression spring 41. Therefore, the impact caused by the rapidly rising packer is absorbed by the shock-absorbing damper 31 of this embodiment as the rod 34 moves into the outer pipe 32. Consequently, the chemical solution supply hose and air hose are not subjected to the impact caused by the rapid rise of the packer, and therefore the chemical solution supply hose and air hose do not buckle.

[0045] As described above, by using the shock-absorbing damper of this embodiment, the chemical supply hose and air hose are not subjected to the impact of the packer's rapid ascent after ground improvement. Therefore, it is possible to prevent buckling of the chemical supply hose and air hose due to the rapid ascent of the packer after chemical injection without requiring any special processing of the packer.

[0046] Next, an embodiment of the chemical injection device equipped with the shock-absorbing damper 31 of this embodiment will be described. The chemical injection device of this embodiment consists of a packer that forms a closed space in a sleeve pipe inserted into a borehole formed in the ground, and releases the chemical solution into this closed space to inject and permeate the chemical solution into the ground for ground improvement, and a shock-absorbing damper that is connected to the upper part of the packer and also connected to a chemical supply hose for supplying the chemical solution to the packer. The shock-absorbing damper is the shock-absorbing damper described above. Therefore, the packer will be described below with reference to the figure.

[0047] Figures 4 and 5 are partial cross-sectional views showing the structure of the packer in this embodiment. Figure 4 shows the upper portion, and Figure 5 shows the lower portion, with 2 being the packer in the figures.

[0048] Furthermore, the packer 2 in this embodiment has a head, to which the packer connecting adapter 40 of the shock-absorbing damper 31 is connected. That is, in Figure 3, 3 is the head, and a bushing 20 is provided at the upper end of this head 3, and the packer connecting adapter 40 of the shock-absorbing damper 31 is connected to the bushing 20.

[0049] An upper packer section is connected to the lower side of the head, and a nozzle section equipped with a chemical discharge port for releasing the chemical is connected to the lower side of the upper packer. An intermediate hose section is connected to the lower side of the nozzle section, and a lower packer section is connected to the lower side of the intermediate hose section. The upper packer section and the lower packer each have an expandable section that expands outward when subjected to fluid pressure such as air toward the outer circumference, and returns to its original shape when the pressure is released. Furthermore, in this embodiment, packer 2 is equipped with a chemical transport path for transporting the chemical to the chemical discharge port of the nozzle section, and a pressurized fluid transport path for supplying pressurized fluid to the inner circumference of the expandable sections of the upper packer section and the lower packer section.

[0050] In this embodiment, the head 3 has a head body 4 and a mantle 5 connected to the lower side of the head body 4.

[0051] Specifically, in the figure, 4 is the head body, and in this embodiment, the head body 4 has a deformed cylindrical shape, and a chemical liquid transport passage 6 is formed inside, the upper end of which opens at the upper end of the head body 4 and the lower end of which opens at the lower end of the head body 4. In this embodiment, the shock-absorbing damper 31 is connected to the upper part of the head body 4 via a bushing 20.

[0052] Next, in the figure, 7 is an air transport path that serves as a pressurized fluid transport path. That is, in this embodiment, the head body 4 has a constricted portion 8 formed in the middle part, and the air transport path 7 is formed inside the head body 4 as a separate system from the chemical transport path 6, with its upper end opening at the constricted portion 8 and its lower end opening at the lower end of the head body 4.

[0053] Next, in the figure, 5 is the mantle. That is, as mentioned above, in this embodiment, the mantle 5 is connected to the lower side of the head body 4. And in this embodiment, the mantle 5 has a round rod shape.

[0054] Furthermore, a chemical transport passage 6 is formed inside the mantle 5, and this passage is connected to a chemical transport passage 6 formed in the head body 4. On the other hand, the outer diameter of the mantle 5 is smaller than the outer diameter of the head body 4, and the opening at the lower end of the air transport passage 7 formed in the head body 4 is exposed to the outer circumference of the mantle 5. When a pressure medium such as air is supplied from the upper end opening of the air transport passage 7 formed in the head body 4, this pressure medium is released to the outer circumference of the mantle 5.

[0055] Next, in the figure, 9 is the upper packer section. That is, in this embodiment, the upper packer section 9 is connected to the lower side of the head 3. The upper packer section 9 is cylindrical in shape, and the mantle 5 is inserted inside the upper packer section 9, with a space between it and the inner wall of the upper packer section 9, and the upper packer section 9 is connected to the lower side of the head 3.

[0056] Now, let's describe the upper packer portion 9. In this embodiment, the upper packer 9 has a pair of substantially cylindrical metal support members 10, and these support members 10 are connected by a substantially cylindrical expansion portion 11. That is, the expansion portion 11 has both ends that are circumferentially located on the opposing end sides of the support members 10, and in this way, the upper packer portion 9 is configured such that the expansion portion 11 connects the pair of support members 10.

[0057] Furthermore, the expansion portion 11 is made of rubber with a steel wire inside, and expands outward when fluid pressure is received from the inner circumference, and can be restored to its original shape when the pressure is released. In the figure, 12 is a fixing bracket for fixing both ends of the expansion portion 11 facing in the longitudinal direction to the support member 10.

[0058] Furthermore, the inner diameter of the support member 10 is larger than the outer diameter of the mantle 5, and as described above, a space is formed between the outer circumference of the mantle 5 and the inner wall of the upper packer portion 9, and this space serves as an air transport passage 7. That is, this air transport passage 7 is connected to the opening at the lower end of the air transport passage 7 formed in the head body 4, and further connected to the inner circumference of the expansion portion 11, and by supplying air as a pressure medium via the head body 4, the expansion portion 11 receives air pressure from the inner circumference to the outer circumference and is able to expand outwards.

[0059] Next, in the figure, 13 is the nozzle section. That is, in this embodiment, the packer 2 has a metal nozzle section 13 connected to the lower side of the upper packer section 9, and a liquid chemical transport path 6 is formed inside this nozzle section 13.

[0060] The liquid chemical transport path 6 formed in the nozzle section 13 is open at the upper end and side of the nozzle section 13, with the side opening serving as the liquid chemical discharge port 14.

[0061] Furthermore, the upper end portion of the nozzle portion 13 is connected to the lower end portion of the mantle 5 on the inner circumference side of the upper packer portion 9, and the chemical transport path 6 formed in the mantle and the chemical transport path 6 formed in the nozzle portion 13 are connected. Thus, the chemical transport path 6 of the packer 2 is composed of the chemical transport path 6 formed in the head body 4, the chemical transport path 6 formed in the mantle 5, and the chemical transport path 6 formed in the nozzle portion 13. As a result, the packer 2 in this embodiment has an upper end that opens to the head 3 and a lower end that has a chemical transport path 6 that leads to the chemical discharge port 14. Therefore, by supplying the chemical from the opening on the head side, it is possible to discharge this chemical from the chemical discharge port 14 into the sleeve pipe outside the packer 2.

[0062] Furthermore, an air transport path 7 is formed in the nozzle section 13, separate from the chemical transport path 6. This air transport path 7 has openings at the upper and lower ends of the nozzle section 13, with the opening at the upper end leading to the pressure medium transport path 7 on the inner circumference side of the upper packer section 9.

[0063] Next, in the figure, 15 is the intermediate hose section. That is, as mentioned above, the intermediate hose section 15 is connected to the lower side of the nozzle section 13, and this intermediate hose section 15 is constructed by connecting a pair of cylindrical metal hose support members 16 with a rubber hose body 17. That is, the upper side of the hose support members 16 is connected to the nozzle section 13, and the hose body 17 has both sides that surround the opposing sides of the pair of hose support members 16, so that the intermediate hose section 15 connected to the nozzle section 13 is constructed in such a way that the hose body 17 connects the pair of hose support members 16.

[0064] Furthermore, the intermediate hose section 15 has a hollow cylindrical shape, and the hollow portion serves as an air transport path 7 connected to the air transport path 7 formed in the nozzle section 13. In addition, both ends of the hose body 17 facing in the longitudinal direction are fixed to the hose support member 16 by fixing fittings 12. The intermediate hose section 15 functions to adequately accommodate the insertion of the packer 2 into localized bends in boreholes, etc., but it is not always necessary.

[0065] Next, in the figure, 18 is the lower packer section. That is, in this embodiment, the lower packer section 18 is connected to the lower side of the intermediate hose section 15. The lower packer section 18, like the upper packer section 9 described above, has a pair of substantially cylindrical metal support members 10, and these support members 10 are connected by substantially cylindrical expansion sections 11. That is, both ends of the expansion section 11 are provided around the opposing ends of the support members 10, and in this way, the lower packer section 18 is configured such that the expansion section 11 connects the pair of support members 10.

[0066] Furthermore, the expansion section 11, like the upper packer section 9 described above, is made of rubber with a steel wire inside, and expands outward when it receives air pressure from the inner circumference, and can return to its original shape when the pressure is released. In the figure, 12 is a fixing bracket for fixing both ends of the expansion section 11, which are oriented in the longitudinal direction, to the support member 10.

[0067] Furthermore, the interior of the lower packer section 18 serves as an air transport passage 7, the upper end of which connects to the air transport passage 7 formed in the intermediate hose section 15, and the lower end is closed by a plug 19. As a result, the air transport passage 7 formed in the head body 4, the air transport passage 7 formed between the outer circumference of the mantle 5 and the inner wall of the upper packer section 9, the air transport passage 7 formed in the nozzle section 13, the air transport passage 7 inside the intermediate hose section 15, and the air transport passage 7 inside the lower packer section 18 form an air transport passage 7 whose upper end has an opening in the head 3 and whose lower end reaches the inner circumference of the expansion section 11 of the lower packer section 18, as well as connecting to the inner circumference of the expansion section 11 of the upper packer section 9 and the inner circumference of the expansion section 11 of the lower packer section 18. Therefore, by supplying a pressure medium such as high-pressure air through the opening of the air transport path 7 formed in the head body 4, the expansion portion 11 of the upper packer portion 9 and the expansion portion 11 of the lower packer portion 18 receive air pressure from the inner circumference to the outer circumference and are able to expand outwards.

[0068] Next, the operation of the chemical injection device 1 of this embodiment, which is configured as described above, will be explained. When performing ground improvement underground with the chemical injection device 1 of this embodiment, the chemical hose is connected to the chemical hose connecting adapter 33 of the shock-absorbing damper 31, and further, the packer connecting adapter 40 of the shock-absorbing damper 31 is connected to the head body 4 of the packer, and the packer 2 in this state is placed in a predetermined position inside the sleeve pipe inserted into the borehole filled with seal grout.

[0069] Then, high-pressure air is sent into the air transport path 7, causing the expansion parts 11 of the upper packer section 9 and the lower packer section 18 to expand outwards, fixing the position of the packer 2 and forming a closed space between the upper packer section 9 and the lower packer section 18.

[0070] Then, in that state, a ground improvement chemical such as cement milk is sent from the chemical supply hose to the chemical transport path 6 of the packer 1 via the shock-absorbing damper 31, and this chemical is released at high pressure into the sleeve pipe from the chemical discharge port 14 to fill the closed space with the chemical. Further chemical release is then performed, and the chemical is released into the seal grout through the circular hole in the sleeve pipe, penetrating the seal grout and injecting into the ground to permeate, thereby improving the ground. After that, the expansion of the expansion section is released, and the fixing of the packer inside the sleeve pipe is released.

[0071] As a result, the packer is pushed by the high pressure at the bottom of the enclosed space and rises rapidly toward the ground. However, as mentioned above, the rod 34 of the shock-absorbing damper 31 is connected to the packer head body 4 via the packer connecting adapter 40, and the rod 34 is designed to retract upward into the outer tube 32 in opposition to the biasing force of the compression spring 41 when it receives pressure in the direction of insertion into the outer tube 32. Therefore, the impact caused by the rapidly rising packer is absorbed by the shock-absorbing damper 31 as the rod 34 moves into the outer tube 32. Consequently, the chemical supply hose and air hose are not subjected to the impact caused by the rapid rise of the packer, and therefore do not buckle.

[0072] Thus, in the chemical injection device of this embodiment, since the shock-absorbing damper is connected to the packer, it is possible to prevent buckling of the chemical supply hose and air hose due to the rapid rise of the packer after chemical injection without requiring any special processing of the packer. [Industrial applicability]

[0073] The shock-absorbing damper for packers and the chemical injection device using the same of the present invention are applicable to all chemical injection devices that form a closed space inside a sleeve pipe and release a chemical solution into this closed space at high pressure. [Explanation of Symbols]

[0074] 2 Packers 3 heads 4 Head body 5 Mantle 6. Chemical solution transport path 7. Pressure fluid transport path 8. Waist area 9 Upper packer section 10 Support member 11 Expansion section 12 Fixing brackets 13 Nozzle section 14 Chemical solution outlet 15 Intermediate hose section 16 Hose support member 17 Hose body 18 Lower packer section 19 plugs 20 Bushings 31. Shock-absorbing damper 32 Outer tube 33 Adapter for connecting chemical solution hoses 34 rods 35 pistons 36 Main body 37 Enlarged section 38 Piston packing 39 Rod Guides 40 Packer connection adapter 41 Compression spring 42 Lip section 43 Outer lip portion 44 Inner lip portion 45 recess

Claims

1. An impact-absorbing damper (31) connected to a packer used for injecting a soil improvement chemical solution into the ground, The outer tube (32) is hollow and long in shape, and has a hollow chemical hose connection adapter (33) attached to its upper end. A rod (34) is hollow and long in shape, and is inserted into the outer tube (32) so as to be movable in the longitudinal direction of the outer tube (32), with a portion of its lower end protruding from the lower end of the outer tube (32), and a hollow packer connecting adapter (40) is attached to its lower end. The outer tube (32) comprises an elastic means (41) positioned between the chemical hose connecting adapter (33) and the upper end of the rod (34), The rod (34) moves into the outer tube (32) when subjected to pressure in the direction of insertion into the outer tube (32), and returns to its original position when the pressure is released due to the biasing force of the elastic means (41). A shock-absorbing damper for a packer, characterized in that the chemical supply hose is connected to the chemical supply hose connecting adapter (33), and the packer is connected to the packer connecting adapter (40), thereby enabling the chemical supply that has been supplied via the chemical supply hose to be supplied to the packer via the inside of the outer tube (32) and the inside of the rod (34).

2. The packer shock-absorbing damper according to claim 1, characterized in that the elastic means (41) is a compression spring.

3. The rod (34) is equipped with a hollow piston (35) at its upper end. The piston (35) is It has a cylindrical main body (36), an upper enlarged portion (37a) formed on the upper end side of the main body (36) with an outer diameter slightly smaller than the inner diameter of the outer tube (32), and a lower enlarged portion (37b) formed near the middle portion when viewed in the vertical direction of the main body (36) with an outer diameter equal to the inner diameter of the outer tube (32), The piston packing (38) is positioned between the upper enlarged portion (37a) and the lower enlarged portion (37b) with a gap formed between them. The packing for the piston (38) is characterized in that it has an outer lip portion (43), an inner lip portion (44), and a recess (45) located between the outer lip portion (43) and the inner lip portion (44) on the surface facing the upper enlarged portion (37a), as described in claim 1 or 2.

4. A chemical injection device comprising an impact-absorbing damper (31) as described in claim 1 and a packer (2) connected to the impact-absorbing damper (31), The packer (2) is, Head (3) and, An upper packer section (9) is connected to the lower side of the head (3) and has an expandable section (11) that expands outward when subjected to fluid pressure toward the outer circumference and returns to its original shape when the pressure is released, A nozzle section (13) is connected to the lower side of the upper packer (9) and is equipped with a chemical discharge port (14) for discharging the chemical solution, The nozzle portion (13) is connected to a lower packer portion (18) which has an expandable portion (11) that expands outward when subjected to fluid pressure toward the outer circumference and returns to its original shape when the pressure is released, The upper end has an opening to the head (3), and the lower end has a chemical transport path (6) that leads to the chemical discharge port (14), The upper end has an opening in the head (3), and the lower end extends to the inner circumference of the expansion portion (11) of the lower packer portion (18), and comprises a pressure fluid transport path (7) that is connected to the inner circumference of the expansion portion (11) of the upper packer portion (9) and the inner circumference of the expansion portion (11) of the lower packer portion (18), A drug injection device characterized in that the shock-absorbing damper (31) is connected to the head (3).

5. The drug injection device according to claim 4, wherein the head (3) comprises a head body (4) having a drug transport passage (6) with an opening at the end of the head (3), and a mantle (5) connected below the head body (4) having a drug transport passage (6) that is continuous with the drug transport passage (6) formed in the head body (4), the upper packer portion (9) is connected to the lower side of the head (3) such that the mantle (5) penetrates the upper packer portion (9) and is connected to the nozzle portion (13) such that the drug transport passage (6) formed in the mantle (5) leads to the drug discharge port (14), and the shock-absorbing damper (31) is connected to the upper part of the head body (4).

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