JP2005330710A - Double packer structure for injection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double packer structure for injection smoothly performing movement in an outer pipe, enhancing liquid tightness in a clearance to the outer pipe in injecting an injection material, and resistant to aging damage. <P>SOLUTION: An inner pipe member 1 has an inner pipe body 2 with discharge ports 21 formed in an outer peripheral surface to discharge the injection material G, and packers mounted to both ends while holding the discharge ports 21 of the inner pipe body 2 between to abut on the inner peripheral surface of the outer pipe 9. The packers have packer bodies 4a, 4b formed of thick-walled elastic bodies of approximately annular shapes with outer diameters smaller than the inner diameter of the outer pipe 9, and piston members 5a, 5b for compressing the packer bodies 4a, 4b in the axis direction. In injecting the injection material G, the packer bodies 4a, 4b mounted to both ends of the discharge ports 21 of the inner pipe bodies 2 are compressed in the axis direction, and the respective packer bodies 4a, 4b are radially projected to abut on the inner peripheral surface of the outer pipe 9 for improving liquid tightness. In moving the inner pipe member 2, compressions of the packer bodies 4a, 4b are released to contract the respective packer bodies 4a, 4b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a double packer structure for injection.

In a ground improvement method such as tunnel ground tip receiving method, water stop injection, or low soil covering or collapsed soil ground strengthening, a chemical solution injection method is adopted in which an injection material is injected into the ground for improvement. Among these chemical injection methods, the double pipe double packer method is used for unconsolidated ground such as sand ground and collapsible rock. The double pipe double packer used in this double pipe double packer construction method will be generally described as follows when used as a tunnel ground tip receiving construction method shown in FIG.
An outer tube 100 in which a large number of injection ports 101, 101,... Are formed at intervals in the longitudinal direction and an inner tube member 110 inserted into the outer tube are used. An inner tube member 110 having packers 112, 112 is inserted into the outer tube 100 before and after the discharge port 111 schematically shown in FIG. 8, and the injection material G is pumped through the inner tube member 110 to discharge the discharge port 111. , 111,... Are discharged through injection ports 101, 101,. And as shown in FIG. 9, it repeats injection | pouring, sliding an injection | pouring inner pipe | tube to each position of injection port 101,101 ..., forms the improvement body Z sequentially, and performs ground improvement (for example, Patent Document 1).
JP 2000-337078 A (page 4, FIGS. 1 to 4)

However, in the above-described invention, the packers 112 and 112 are made of an elastic body such as rubber. If the outer diameter of the packers 112 and 112 is the same as the inner diameter of the outer tube, the inner tube member 110 is placed in the outer tube 100. There is a problem that the frictional resistance of sliding on the inner peripheral surface of the outer tube of the elastic body is increased, and the construction efficiency is deteriorated. Further, if the outer diameters of the packers 112 and 112 are smaller than the inner diameter of the outer tube, the liquid-tightness is lacking, and when the injection material G is pumped through the inner tube member 110, the outer periphery of the packers 112 and 112 and the outer tube The injection material G leaks from the space between the inner peripheral surface and the injection pressure and the injection amount of the injection material G is reduced, and the sufficient improvement body Z cannot be formed. Therefore, the surrounding ground is sufficiently improved. In order to achieve this, excessive injection pressure and injection volume were required, which increased the construction cost.
Further, the packers 112 and 112 are constituted by bags such as fibers and fiber reinforced rubber, and the packers 112 and 112 are inflated by supplying water or the like into the bag to contact the inner peripheral surface of the outer tube 100. In some cases, the packers 112 and 112 are contracted when the inside of the outer tube 100 is slid. However, the expansion and contraction are repeated and the packers 112 and 112 are brought into contact with the inner peripheral surface of the outer tube. It cannot prevent damage over time, requires frequent replacement, and is troublesome.

  Accordingly, the main problem of the present invention is that the double pipe for injection that smoothly moves in the outer pipe, enhances the liquid tightness of the gap with the outer pipe when injecting the injection material, and is resistant to damage over time. To provide a packer structure.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
The invention described in claim 1 includes an inner tube member that is movable in the axial direction in an outer tube in which a plurality of injection ports for injecting an injection material into the surrounding ground are formed at intervals in the longitudinal direction. In the double packer structure for injection, the inner tube member is attached to both ends of the inner tube main body in which a discharge port for discharging the injection material is formed on the outer peripheral surface and the discharge port of the inner tube main body sandwiched therebetween. A packer portion capable of contacting the inner peripheral surface of the outer tube, and the packer portion is formed of a substantially annular thick elastic body having an outer diameter smaller than the inner diameter of the outer tube. A packer body, and a piston member that compresses the packer body in the axial direction thereof. When injecting the injection material, the packer bodies attached to both ends of the inner pipe body are pivoted. Before compressing in the direction of the heart and projecting each packer body radially It is in contact with the inner peripheral surface of the outer tube to achieve liquid-tightness, and when the inner tube member moves, the compression of the packer body is released and each packer body is contracted in the radial direction. This is a double packer structure for injection.

(Function and effect)
The packer portion has a packer body formed of a substantially annular thick elastic body having an outer diameter smaller than the inner diameter of the outer tube, and a piston member that compresses the packer body in the axial direction. When injecting the injection material, the packer bodies attached to both ends of the inner tube body are compressed in the axial direction, and each packer body is extended in the radial direction to the inner peripheral surface of the outer tube. When the inner tube member moves, the compression of the packer body is released and each packer body is contracted in the radial direction so that the movement in the outer tube is performed smoothly. In addition, it is possible to improve the liquid tightness of the gap with the outer tube when the injection material is injected. In addition, since the packer is a substantially annular thick elastic body, it is more resistant to damage over time than the conventional one made of bags of fibers, fiber reinforced rubber, etc., and does not require frequent replacement. , It can reduce the labor of construction.

<Invention of Claim 2>
In the invention according to claim 2, cylinder chambers are respectively formed inside both ends of the inner pipe main body, the piston member is housed in the cylinder chamber, and a cylindrical body portion that can slide the cylinder chamber; A pressing portion that presses the packer main body and is formed at the tip of the cylindrical body portion, and is configured to press the cylindrical packer body by pressing the cylindrical body portion by fluid feeding into the cylinder chamber. The double packer structure for injection according to claim 1, wherein

(Function and effect)
Since fluid pressure is used as a factor that causes the packer body to expand, work management from the ground is easy, and since it has a simple configuration, there is little risk of breakage and excellent work stability.

<Invention of Claim 3>
According to a third aspect of the present invention, the inner tube member is integrated by an inner member in which the inner tube main body and the packer portion are inserted through the shaft, and the inner peripheral surface of the both end portions of the inner tube main body and the inner tube member are integrated. The double packer structure for injection according to claim 2, wherein cylinder chambers are formed between the outer peripheral surfaces of the materials.

(Function and effect)
The same effect as that of the invention of claim 2 can be obtained.

<Invention of Claim 4>
According to a fourth aspect of the present invention, a compression spring that is compressed as the cylindrical portion is pressed is attached to the cylindrical portion of the piston member, and the repulsive force of the compression spring is used to reduce the radius of the packer body. The double packer structure for injection according to claim 2 or 3, wherein the structure is configured to bias contraction in a direction.

(Function and effect)
When a thick elastic body is used as the packer body, it takes time to contract from the expanded state, and the construction efficiency is deteriorated. Therefore, a compression spring to be compressed is attached to the cylinder portion of the piston member as the cylinder portion is pressed, and the repulsive force of the compression spring biases the contraction of the packer body. Thereby, the contraction process of the thick elastic body can be facilitated by utilizing the repulsive force of the compressed spring, and the construction efficiency can be improved.

<Invention of Claim 5>
According to a fifth aspect of the present invention, there is provided an enlarged inner diameter portion of the inner peripheral surface of the cylindrical body portion of the piston member, and the inner member which faces the enlarged inner diameter portion and has stepped portions formed on both end sides of the inner pipe main body. A compression spring is provided between the outer peripheral surface and the compressed outer diameter portion. When the cylindrical body portion is pressed, the compression spring is compressed using the stepped portion as a stopper, and the repulsive force of the compression spring The double packer structure for injection according to claim 2 or 3, wherein the structure is configured to urge contraction of the packer body in the radial direction.

(Function and effect)
The same effect as that of the invention of claim 4 can be obtained.

<Invention of Claim 6>
The invention according to claim 6 is the injection double according to any one of claims 3 to 5, wherein the inner member is configured by a substantially concentric double pipe which becomes a flow path for the injection material and the fluid, respectively. Packer structure.

(Function and effect)
The member can be shared, and the inner tube member can be made compact.

According to the present invention, the movement in the outer tube can be performed smoothly, the liquid-tightness of the gap with the outer tube can be increased during the injection of the injection material, and resistance to damage over time can be provided. The benefits of

Embodiments of the present invention will be described below.
<Configuration of Double Packer Structure for Injection According to the Present Invention>
The structure of the double packer structure for injection will be described with reference to FIGS. 1 is a front view for explaining a state in which the inner tube member is inserted into the outer tube, FIG. 2 is a front view for explaining an injection state of the inner tube member, and FIG. 3 is an inner tube member. 4 is a partial cross-sectional view of the inner tube member on the proximal end side, FIG. 5 is a partial cross-sectional view of the inner tube member on the distal end side, and FIG. 6 is a view of the proximal end side during injection. It is a fragmentary sectional view for demonstrating the condition of a piston member and a compression spring.
As shown in FIG. 1, the inner pipe member 1 according to the present invention is provided in an outer pipe 9 in which a plurality of injection ports 91, 91,... For injecting an injection material G into the surrounding ground are formed at intervals in the longitudinal direction. Inserted and movable in the axial direction. The inner pipe member 1 includes an inner pipe body 2 in which discharge ports 21, 21,... For discharging the injection material G are formed on substantially the same circumference on the outer peripheral surface, and the inner pipe body 2 is provided in the inner pipe body 2. A substantially concentric double pipe 3 as an inner member, which is a flow path for each of G and fluid W, and attached to both ends across the discharge ports 21, 21,... Of the inner pipe 2, And a packer portion having packer bodies 4a and 4b that can come into contact with the inner peripheral surface.

  As described above, the inner tube main body 2 has a substantially concentric circular double tube 3 as a flow path for the injection material G and the fluid W as an inner member for integration with the packer portion. The outlets 21, 21,... For discharging the injection material G are formed on substantially the same circumference while being inserted and inserted. As shown in FIGS. 4 and 5, both end portions of the inner tube main body 2 have a relatively larger inner diameter than the intermediate portion, and the inside of the inner tube main body 2, that is, the proximal end side end portion of the inner tube main body 2. Between the inner peripheral surface and the outer peripheral surface of the double tube 3 (the outer peripheral surface of the outer tube 31), the cylinder chamber 22a and the inner peripheral surface of the end of the inner tube main body 2 and the outer peripheral surface of the rod member 7 are provided. A cylinder chamber 22b is formed between them, and cylinder portions 52 and 52 of piston members 5a and 5b, which will be described later, are slidably accommodated in the cylinder chambers 22a and 22b.

  The double pipe 3 is connected at its base end side to a pressure feeding hose 33 and the like, and feeds each of the injection material G and fluid W such as water into the double pipe 3. Here, the double pipe 3 is formed in a substantially concentric shape, and the injection material G and the fluid W are configured as separate flow paths. In the embodiment shown in FIG. A flow path is used, and the fluid W such as water has the inner pipe 32 as a flow path. As shown in FIG. 4, the outer pipe 31 extends to the vicinity of the proximal end of the inner pipe main body 2, and the injection material G fed by pressure in the outer pipe 31 is an intermediate part of the inner pipe main body 2. Are discharged from the discharge ports 21, 21,... As shown in FIG. 5, the inner tube 32 extends to the vicinity of the end (face side) end of the inner tube main body 2, and the fluid W pumped through the inner tube 32 is shown in FIG. 4. As described above, the gas is ejected from the first jet port 32A formed on the outer peripheral surface of the inner tube 32, enters the cylinder chamber 22a from the second jet port 31A formed on the outer peripheral surface of the outer tube 31, and the piston member 5a The edge of the cylindrical part 52 and the ring member 54 are pressed. Further, the fluid W ejected from the tip of the inner tube 32 enters the cylinder chamber 22b through the ejection port 7A formed in the rod member 7 as an inner member, and the edge and ring of the cylindrical portion 52 of the piston member 5b. The member 54 is pressed. Accordingly, when the injection material G is injected, as shown in FIG. 2, the piston members 5a and 5b are extended, and the packer bodies 4a and 4b are compressed in the axial direction, and the respective packer bodies 4a and 4b are compressed. Is extended in the radial direction to abut against the inner peripheral surface of the outer tube 9 to achieve liquid-tightness, and when the inner tube member 1 moves, the pressure of the fluid W is released to release the packer bodies 4a and 4b. Is released so that the respective packer bodies 4a and 4b can be contracted. As will be described later, fluid pressure is used as a factor that causes the packer bodies 4a and 4b to expand. Therefore, work management from the ground is easy and the structure is simple, so there is little risk of breakage and excellent work stability. Is.

  In addition, as the injection material G, cement-bentonite-based seal grout, cement-based or water glass-based grouting for osmotic injection, and the like can be used, and as the fluid W, water is generally used. Since the function is to provide a fluid pressure for extending the piston members 5a and 5b, a fluid such as oil or air may be used.

  The packer portion includes the packer bodies 4a and 4b described above and piston members 5a and 5b that compress the packer bodies 4a and 4b in the axial direction. In addition, pressing plates 42 and 42 and pressure receiving plates 43 and 43 are attached to both ends of the packer bodies 4a and 4b, respectively, and sandwich the packer bodies 4a and 4b. The packer bodies 4 a and 4 b are formed of an elastic body made of a substantially annular thick natural rubber or synthetic rubber having an outer diameter smaller than the inner diameter of the outer tube 9. By forming the packer body 4a, 4b with a thick elastic body, compared to a packer that expands and contracts by supplying water etc. into the bag body such as fibers and fiber reinforced rubber as in the conventional example, It is resistant to damage over time due to repeated expansion and contraction and contact with the inner peripheral surface of the outer tube, and frequent replacement is unnecessary, so that troublesome work can be saved. Further, the elastic body has a hollow portion formed from the viewpoint of easiness of expansion (expansion) at the time of compression, easiness of removal, and the like, and a ring member 41 is fitted in the hollow portion, and this ring The double pipe 3 or the rod member 7 penetrates the inner periphery of the member 41. The ring member 41 is for restricting the movement of the pressing plate 42, and for restricting excessive compression of the packer bodies 4a and 4b from the viewpoint of preventing the elastic body from being damaged. Further, the base end side of the packer main body 4a and the tip end side of the packer main body 4b are taper cut so that the outer peripheral surface of the elastic body has a small diameter toward the pressure receiving plate 43, and the overhang (expands) during compression. ) It is easy. Although the pressing plate 42 and the pressure receiving plate 43 are not necessarily required, they apply uniform stress to the entire side surfaces of the packer bodies 4a and 4b. It is preferable to attach it because it can be secured stably.

  As described above, the piston members 5a and 5b are housed in the cylinder chambers 22a and 22b. The piston members 5a and 5b are formed at the cylinder body 52 that can slide the cylinder chambers 22a and 22b, and at the tip of the cylinder body. And a pressing portion 51 that presses 4a and 4b. A protrusion 52B is formed at the end edge of the cylindrical body 52, and the ring members 54, 54 are locked in the axial direction by the protrusion 52B. The ring members 54, 54 pivot on the compression springs 53, 53. It is locked in the direction of the heart. Here, the compression spring 53 on the proximal end side is opposed to the expanded inner diameter portion 52A on the inner peripheral surface of the cylindrical body portion 52 of the piston member 5a and the expanded inner diameter portion 52A, and on the proximal end side of the inner pipe main body 2. A compression spring 53 on the front end side is provided between the outer peripheral surface of the outer tube 31 forming the step portion 31B (the outer peripheral surface of the double tube 3) and the reduced outer diameter portion 31C. An enlarged inner diameter portion 52A on the inner peripheral surface of the portion 52, and a reduced outer diameter portion 7C on the outer peripheral surface of the rod member 7 facing the enlarged inner diameter portion 52A and forming a stepped portion 7B on the distal end side of the inner tube body 2. Is installed inside. When the fluid W is pumped into the cylinder chambers 22a and 22b, the end of the cylindrical portion 52 of the piston members 5a and 5b and the ring member 54 are pressed, and the packer bodies 4a and 4b are pressed. The compression springs 53, 53 are compressed with step portions 31B, 7B (not shown in FIG. 6) as stoppers. When the pressure of the fluid W into the cylinder chambers 22a and 22b is released (when pumping is not performed), the packer bodies 4a and 4b contract, but at this time, the step portions 31B and 7B (see FIG. 6) (not shown in FIG. 6), the repulsive force of the compression springs 53, 53 acting as a stopper acts to urge the packer bodies 4a, 4b to contract, thereby facilitating the contraction process of the thick elastic body and improving the construction efficiency. Can be improved. That is, when injecting the injection material G, as shown in FIG. 2, the piston members 5a and 5b are extended, the packer bodies 4a and 4b are compressed in the axial direction, and the respective packer bodies 4a and 4b are compressed. It projects in the radial direction to contact the inner peripheral surface of the outer tube 9 to achieve liquid-tightness, and when the inner tube member 1 moves, the pressure of the fluid W is released to compress the packer bodies 4a and 4b. Is released, and the repulsive force of the compression springs 53, 53 urges the shrinkage of the packer bodies 4a, 4b while contracting the packer bodies 4a, 4b to facilitate the contraction process of the thick elastic body. It is improving efficiency.

  Further, the pressing portion 51 has a disk shape, presses the pressing plates 42, 42, and uniformly applies stress to the entire side surfaces of the packer bodies 4a, 4b via the pressing plates 42, 42. Note that the pressing portion 51 is not always necessary, and in this case, the pressing plates 42 and 42 are pressed by the cylindrical portion 52.

  On the proximal end side of the packer body 4a and the distal end side of the packer body 4b, the ring-shaped spacers 62, 62 and the ring-shaped coupling members 63A of the roller units 63, 63 are provided at the tip of the pressure receiving plates 43, 43 described above. 63 A and the fasteners 64 and 64 are penetrated by the double pipe 3 or the rod member 7.

  The roller units 63, 63 are provided with ring-shaped couplers 63A, 63A in which central portions of the disks are formed, and roller members 63B, 63B,... Coupled to the disk surfaces of the couplers 63A, 63A. The rollers of the roller members 63B, 63B,... Slide and rotate on the inner peripheral surface of the outer tube 9, facilitating movement of the inner tube member 1 in the outer tube 9, and The distance in the radial direction from the inner tube member 1 is kept constant. Since the roller members 63B, 63B,... Also have a function of keeping the radial interval between the outer tube 9 and the inner tube member 1 constant, at least three or more on the disk surface of the coupler 63A, and It is preferable to attach them at a predetermined interval (for example, the central angle of the adjacent roller members 63B and 63B is set to 120 degrees). The spacer 62 may be arbitrarily attached.

  The fasteners 64, 64 are screw members such as nuts, and are screwed to the outer peripheral surfaces of the double tube 3 and the rod member 7 as inner members in which the inner tube main body 2 and the packer portion are inserted through the shaft. The packer portion and the inner pipe main body 2 are integrated via the ring-shaped spacers 62 and 62 and the ring-shaped couplers 63A and 63A of the roller units 63 and 63. Instead of the rod member 7, the double tube 3 may be extended to the tip side, and the tip opening may be sealed with a sealing member (not shown) or the like.

  In the figure, reference numerals 81, 81,... Denote O-rings, which are appropriately attached in the vicinity of the joint portion of each member in order to ensure liquid tightness.

<Chemical liquid injection method using the double packer structure for injection according to the present invention>
As the outer tube 9 formed with a large number of inlets 91, 91... Spaced apart in the longitudinal direction, for example, a long one of about 12.5 m is used, and a drilling machine (not shown) is attached thereto, The outer tube 9 is inserted into a natural ground or a target ground. When drilling, it can be inserted by drilling with a drilling rod (not shown) having a drilling bit at the tip prepared separately, and moving the outer tube 9 forward as the drilling proceeds. The outer tube 9 can be made a predetermined length by addition.

  Next, the inner tube member 1 is inserted into the outer tube 9, the inner tube member 1 is moved, and positioning is performed so as to correspond to the inlet 91 at the first desired position. Then, a fluid W such as water is pumped into the cylinder chambers 22a and 22b, the edges of the cylindrical portion 52 of the piston members 5a and 5b and the ring member 54 are pressed, and the packer bodies 4a and 4b are compressed in the radial direction. The liquid tube is extended and brought into contact with the inner peripheral surface of the outer tube 9 to achieve liquid tightness.

  Next, the injection material G is pumped from the conveying hose 33, and the injection material G is discharged from the discharge port 21 of the inner tube main body 2 into the space surrounded by the inner peripheral surface of the outer tube 9 and the packer main bodies 4a and 4b. It injects into a natural ground, a surrounding ground, etc. from the injection inlet 91 of the pipe | tube 9. FIG.

  After the injection is completed, the injection pressure of the fluid W such as water and the injection material G is released, the packer bodies 4a and 4b are contracted, and the inner pipe member 1 is made to correspond to the injection port 91 at the second desired position. It may be moved and the above steps may be repeated. And the same process should just be performed also with respect to the injection port 91 of the 3rd, 4th, ... desired position. In the above step, the injection material G and the fluid W such as water are discharged as separate steps, but the injection material G and the fluid W such as water may be discharged simultaneously.

  In addition, the chemical solution injection method using the double packer structure for injection according to the present invention includes a ground improvement method such as a tunnel ground top receiving method, a still water injection, or a low soil covering part or a ground collapse strengthening of collapsible soil, It can be used for reinforcement of bridge piers such as bridges, side injection of shafts, etc., which are carried out by driving the outer tube 9 from the vertical direction.

It is a front view for demonstrating the state which inserted the inner pipe member in the outer pipe. It is a front view for demonstrating the injection | pouring state of an inner pipe member. It is sectional drawing of an inner pipe member. It is a fragmentary sectional view of the inner tube member on the base end side. It is a fragmentary sectional view of the inner tube member on the tip side. It is a fragmentary sectional view for demonstrating the condition of the piston member and compression spring of the base end side at the time of injection | pouring. It is a longitudinal cross-sectional view of the insertion arrangement form of the outer pipe in the tunnel ground tip receiving method. It is a longitudinal cross-sectional view of the state which inserted the inner pipe member in the outer pipe. It is a longitudinal cross-sectional view for demonstrating the injection | pouring operation | work in a tunnel ground tip receiving method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inner pipe member, 2 ... Inner pipe main body, 3 ... Double pipe, 4a, 4b ... Packer main body, 5a, 5b ... Piston member, 7 ... Rod member, 7A ... Jet port, 7B ... Step part, 7C ... Shrinkage Outer diameter portion, 9 ... outer tube, 21 ... discharge port, 22 ... cylinder chamber, 31 ... outer tube, 31A ... second fluid ejection port, 31B ... stepped portion, 31C ... reduced outer diameter portion, 32 ... inner tube, 32A ... first fluid jet, 33 ... conveying hose, 41 ... ring member, 42 ... pressing plate, 43 ... pressure receiving plate, 51 ... pressing portion, 52 ... cylindrical body portion, 52A ... expanded inner diameter portion, 52B ... projection, 53 ... Compression spring, 54 ... Ring member, 62 ... Spacer, 63 ... Roller unit, 63A ... Connecting tool, 63B ... Roller, 64 ... Fastener, 81 ... O-ring, 91 ... Injection port, 100 ... Outer tube, 101 ... Inlet 110, inner tube member 111, discharge port 112 Packer, Z ... improved body.

Claims (6)

An injection double packer structure comprising an inner tube member that is movable in the axial direction in an outer tube in which a plurality of injection ports for injecting an injection material into the surrounding ground are spaced apart in the longitudinal direction. ,
The inner tube member is attached to both ends of the inner tube main body in which a discharge port for discharging the injection material is formed on the outer peripheral surface and the discharge port of the inner tube main body, and is attached to the inner peripheral surface of the outer tube. A packer portion capable of contacting,
The packer portion includes a packer body formed of a substantially annular thick elastic body having an outer diameter smaller than the inner diameter of the outer tube, and a piston member that compresses the packer body in the axial direction thereof. Have
When injecting the injection material, the packer bodies attached to both ends of the inner pipe main body are compressed in the axial direction, and the respective packer main bodies are projected in the radial direction so that the inner circumference of the outer pipe is Contact the surface to achieve liquid-tightness,
When moving the inner tube member, the compression of the packer body is released, and each packer body is contracted in the radial direction.
A double packer structure for injection characterized by this. Cylinder chambers are formed inside both ends of the inner pipe body,
The piston member is housed in the cylinder chamber, and includes a cylindrical body portion that can slide the cylinder chamber, and a pressing portion that is formed at the tip of the cylindrical body portion and presses the packer body.
The double packer structure for injection according to claim 1, wherein the cylindrical body portion is pressed by pressing a fluid into the cylinder chamber to press the packer body.   The inner tube member is integrated by an inner member that is inserted through the inner tube main body and the packer portion, and between the inner peripheral surface of both ends of the inner tube main body and the outer peripheral surface of the inner member. The double packer structure for injection according to claim 2, wherein each of the cylinder chambers is formed.   A compression spring that is compressed as the cylinder portion is pressed is attached to the cylinder portion of the piston member, and the repulsive force of the compression spring urges the contraction of the packer body in the radial direction. The double packer structure for injection according to claim 2 or 3, wherein the double packer structure is for injection. An enlarged inner diameter portion of the inner peripheral surface of the cylindrical body portion of the piston member, and a reduced outer diameter portion of the outer peripheral surface of the inner member facing the enlarged inner diameter portion and having stepped portions formed on both end sides of the inner tube main body. A compression spring is installed between
When the cylindrical body portion is pressed, the compression spring is compressed using the stepped portion as a stopper, and the repulsive force of the compression spring urges contraction of the packer body in the radial direction. The double packer structure for injection according to claim 2 or 3.   The double packer structure for injection according to any one of claims 3 to 5, wherein the inner member is configured by a substantially concentric double pipe serving as a flow path for each of the injection material and the fluid.

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