JP2020073882A - Double tube - Google Patents

Abstract

To provide a double tube capable of suppressing a gap between an inner tube body and an outer tube body from communicating outward even when the inner tube body expands during frozen preservation of a sample.SOLUTION: A double tube 1 is for keeping a collected sample in frozen preservation. The double tube comprises: a bottomed inner tube body 11 into which the collected sample is put; a bottomed outer tube body 12 that is attached to the inner tube body such that the inner tube body is inserted so that a gap 15 is formed between the outer tube body and the inner tube body, and the opening side of the gap is sealed; and a plug member 3 that seals the inner tube body, wherein a lower surface 11g of the inner tube body slidably contacts a bottom surface 12d of the outer tube body, and the inner tube body is reduced in diameter on a bottom side 11d compared to an opening side 11c.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a double tube for storing collected samples.

  There is a blood collection tube as a container for storing the collected sample, specifically, blood. In some blood collection tubes, a liquid additive is contained in advance in order to enable a predetermined analysis, and the blood collection tube is evacuated to have a vacuum state. Therefore, the blood collection tube has a double tube structure in order to prevent the liquid additive from evaporating and maintain a vacuum even when the blood collection tube is not used for a long period of time. As such a blood collection tube, a container assembly as disclosed in Patent Document 1, for example, is known.

  The container assembly has an outer tube body, an inner tube body, and a lid, and the inner tube body is inserted into the outer tube body to form a double tube together with the outer tube body. In the container assembly, the open end of the outer tube is closed by the lid, and the inside of the double tube is in a vacuum state by performing a pressure reduction process.

Patent No. 4534506

  The collected blood has various uses, and is used for testing components of blood or for testing genes. There is cryopreservation as a method for preserving the collected blood, but red blood cells contained in blood are destroyed when cryopreserved. When conducting a component test or the like, the test value may change if the red blood cells are destroyed, so whole blood cannot be stored frozen. On the other hand, since the gene is not destroyed by freezing, in the genetic test, whole blood is frozen at a low temperature of around −80 ° C. and stored for a long time in order to preserve the blood for a long time.

  When freezing whole blood, the water in the blood starts to freeze at 0 ° C. or lower, and the freezing causes the water in the blood to expand. The expansion stress of the water in the blood causes the expansion stress toward the outer side in the radial direction on the inner tube, and expands a part of the inner tube outward in the radial direction. The part of the expansion that eventually hits the outer tube, and the water in the blood causes the outer tube and the inner tube to expand radially outward. As a result, the outer pipe body may be damaged, or the outer pipe body may suppress the expansion of the inner pipe body, so that the inner pipe body may be damaged.

Having understood that such a phenomenon may occur, the inventor has examined the case where the container assembly of Patent Document 1 which is premised to be used when blood is stored at room temperature is used in cryopreservation. .. In a straight tube such as the inner tube of Patent Document 1, the inner diameter of the inner tube in the axial direction is substantially uniform. In this case, the stress acting on the inner pipe body is substantially constant regardless of the position of the inner peripheral surface. Therefore, the part of the inner tubular body on the top side of the opening may expand. In this case, the expanded portion hits the outer tubular body and pushes the outer tubular body outward, so that the outer tubular body separates from the opening top portion of the inner tubular body, and the gap between the inner tubular body and the outer tubular body becomes outward. Come to communicate. When the lid is opened after the blood is thawed in this state, outside air (that is, air) passes between the inner tube and the outer tube through the communication part between the outer tube and the opening top of the inner tube. It flows through the gap between them and further into the inner tube through the damaged part of the inner tube. As a result, bubbles are generated in the blood in the inner tube, and the bubbles climb to the liquid level and burst there, so that the blood in the inner tube is scattered and may jump out of the container assembly.

  Therefore, the present invention is a double pipe that can prevent the gap between the inner pipe body and the outer pipe body from communicating outward even if the inner pipe body largely expands, and prevent blood from leaking to the outside. Is intended to provide.

  The double tube of the present invention is a double tube for storing a collected sample, the inner tube having a bottom having the sample collected therein, and the inner tube so that a gap is formed between the inner tube and the inner tube. A bottom surface of the inner tube body, which includes a bottomed outer tube body into which the tube body is inserted and which is attached to the inner tube body so as to seal the opening side of the gap, and a plug member which seals the inner tube body. Is slidably in contact with the bottom surface of the outer tubular body, and the inner tubular body has a diameter reduced on the bottom side compared to the opening side of the inner tubular body.

  According to the present invention, since the lower surface of the inner tube can be slidable on the bottom surface of the outer tube, when the inner tube expands and hits the outer tube, the outer tube opposes the inner tube. Can be pushed back to the side. That is, the expansion of the inner tubular body can be allowed by the amount that can be pushed back, and the allowable amount for the expansion of the sample can be increased. With this, even if the inner tubular body is largely expanded, it is possible to prevent the gap between the inner tubular body and the outer tubular body from communicating outward, and it is possible to prevent blood from leaking to the outside.

  ADVANTAGE OF THE INVENTION According to this invention, even if the inner pipe expands, the gap between the inner pipe and the outer pipe can be prevented from communicating outward, and blood can be prevented from leaking to the outside.

It is the front view which looked at the double pipe which is an embodiment of the present invention from the front. FIG. 2 is a cross-sectional view of the double pipe of FIG. 1 taken along a cutting plane II-II. It is sectional drawing which shows the inner pipe body with which the double pipe of FIG. 2 is equipped. It is an expanded sectional view which expands and shows the area | region X1 of the double pipe of FIG. It is an expanded sectional view which expands and shows the area | region X2 of the double pipe of FIG.

  Hereinafter, a double pipe 1 according to an embodiment of the present invention will be described with reference to the above-mentioned drawings. In addition, the concept of the direction used in the following description is used for convenience in description, and the direction of the configuration of the invention is not limited to the direction. The double pipe 1 described below is only one embodiment of the present invention. Therefore, the present invention is not limited to the embodiments, and additions, deletions, and modifications can be made without departing from the spirit of the invention.

  The double tube 1 shown in FIG. 1 (hereinafter referred to as “double tube 1”) is used when cryopreserving a collected sample, for example, blood at a temperature of −15 ° C. or lower. Specifically, the double tube 1 is stored at −30 ° C. or lower in order to stop the reaction of the enzyme contained in the sample (medical freeze), and is also used for long-term storage (deep freeze) of the sample used for genetic testing. It is preferably used when storing at -70 ° C or lower. The double pipe 1 used in this manner includes a pipe body 2 and a plug member 3.

The tube body 2 is a so-called double tube and has an inner tube body 11 and an outer tube body 12 as shown in FIG. The inner tube body 11 is a long bottomed tube extending along the axis L1 thereof, and blood collected from a blood vessel can be put therein. The inner tubular body 11 is made of a transparent thermoplastic resin such as polyethylene (PE), polyethylene terephthalate (PET), PP (polypropylene), glycol-modified polyester, PS (polystyrene), and is formed by injection molding, for example. Being manufactured. Further, as shown in FIG. 3, the inner tubular body 11 is formed in a tapered shape in which a cylindrical portion 11a forming a side surface portion is reduced in diameter toward the bottom side.

  The shape of the cylindrical portion 11a will be described in more detail. The cylindrical portion 11a has an intermediate tapered portion 11b at its intermediate portion, an opening side tapered portion 11c on the opening end side of the intermediate tapered portion 11b, and an intermediate tapered portion. A bottom taper portion 11d is provided on the bottom side of the portion 11b. These three tapered portions 11b to 11d have a tapered shape in which the diameter is reduced toward the bottom side, and the intermediate tapered portion 11b is smoothly connected to the opening side tapered portion 11c and the bottom side tapered portion 11d. The gradient of the intermediate taper portion 11b is larger than the gradient of the opening-side taper portion 11c and the bottom-side taper portion 11d. By thus increasing the gradient of the intermediate taper portion 11b, the opening-side taper portion 11c. Has a larger inner diameter, and the bottom side tapered portion 11d has a smaller inner diameter.

  Further, a flange 11e is formed at the opening end 11h of the inner tube body 11 so as to project outward in the radial direction, and the outer peripheral surface of the flange 11e extends substantially straight along the axis L1. That is, the opening end portion 11h is a straight tube. Further, the bottom portion 11f of the inner tubular body 11 is partially spherical as shown in FIG. 4, and the lower surface 11g of the bottom portion 11f of the inner tubular body 11 and the portion around the axis L1 is the inner side of the inner tubular body 11. It is depressed. As a result, the lower surface 11g of the inner tubular body 11 is formed in an annular shape. The inner tube body 11 having such a shape is inserted into the outer tube body 12.

  As shown in FIG. 2, the outer tubular body 12 is a long straight cylindrical pipe having a bottom and extending along the axis L2, and includes, for example, polyethylene (PE), polyethylene terephthalate (PET), PP (polypropylene), It is made of a translucent thermoplastic resin such as glycol-modified polyester or PS (polystyrene). In this embodiment, the outer tubular body 12 is made of PET having a higher glass transition point than PE. However, the combination of the materials of the inner tube body and the outer tube body is not limited to the exemplified one, and the glass transition point of the material of the outer tube body 12 may be lower than the glass transition point of the inner tube body 11. The outer tube body 12 is manufactured by, for example, injection molding. Therefore, the cylindrical portion 12a of the outer tubular body 12 is provided with a draft, but its inner peripheral surface is formed substantially straight along the axis L2. The bottom portion 12b of the outer tubular body 12 is also partially spherical as shown in FIG. 4, and the lower surface 12c of the bottom portion 12b of the outer tubular body 12 and the portion around the axis L2 is inside the outer tubular body 12. It is depressed. Further, the bottom surface 12d of the outer tube body 12 (that is, the inner surface of the bottom portion 12b) is flat so as to be substantially orthogonal to the axis L2, and the lower surface 11g of the inserted inner tube body 11 becomes the bottom surface 12d. Abutting.

The outer tube body 12 thus formed is formed to be longer than the inner tube body 11, and the entire inner tube body 11 is accommodated in the outer tube body 12. That is, the entire inner tube body 11 is covered with the outer tube body 12. Further, as shown in FIG. 5, the outer diameter of the inner tube body 11 is the largest at the flange 11e, and the inner peripheral surface of the outer tube body 12 is fitted while the flange 11e achieves sealing. It fits in the insertion part 12h. That is, the outer diameter of the flange 11e portion of the inner pipe body 11 is formed to be substantially the same as (or larger than) the inner diameter of the outer pipe body 12. On the other hand, the inner tubular body 11 has a tapered shape in which the cylindrical portion 11a excluding the opening end 11h is reduced in diameter toward the bottom side, and the inner peripheral surface of the outer tubular body 12 is substantially straight along the axis L2. Is formed in. Therefore, there is a gap 15 between the inner peripheral surface of the outer tubular body 12 and the outer peripheral surface of the inner tubular body 11. In the present embodiment, the inner peripheral surface of the outer tubular body 12 and the outer peripheral surface of the opening-side tapered portion 11c are not in contact with each other in the gap 15, and the inner peripheral surface of the outer tubular body 12 and the outer peripheral surface of the opening-side tapered portion 11c do not contact each other. The space between them is the narrowest. Further, in the gap 15, the space between the inner peripheral surface of the outer tubular body 12 and the outer peripheral surface of the bottom taper portion 11d (in particular, near the bottom portion 11f) is widest. Further, the interval H of the gap 15 is within a predetermined range between the inner peripheral surface of the outer tubular body 12 and the outer peripheral surface of the bottom taper portion 11d, for example, 0.1 mm ≦ H ≦ 2.5 mm, preferably 0.5 mm. It is designed to fit within ≦ H ≦ 1.0 mm. In the present embodiment, the distance H1 at the boundary between the bottom taper portion 11d and the intermediate taper portion 11b is 0.8 mm (see FIG. 4), and the distance H2 at the boundary between the bottom taper portion 11d and the bottom portion 11f. Is 0.9 mm (see FIG. 1).

  In the tube body 2 configured in this way, the inner tube body 11 is inserted into the outer tube body 12 so that the axes L1 and L2 of the tube body 2 are substantially aligned with each other, and the lower surface 11g of the inner tube body 11 is the outer tube body 12. Is in contact with the bottom surface 12d of the. Further, the opening end portion 11h of the inner pipe body 11 is located lower than the opening end of the outer pipe body 12 in the axial direction (direction along the axes L1 and L2), and as shown in FIG. The flange 11e is housed in the outer tube body 12.

  The flange 11e is fitted to the inner peripheral surface of the outer tubular body 12 in a state where a seal is achieved, and thereby the gap 15 between the inner tubular body 11 and the outer tubular body 12 is sealed. In the tube body 2, the outer peripheral surface of the flange 11e (that is, the outer peripheral surface of the opening end portion 11h) is formed in a straight shape in accordance with the shape of the fitting insertion portion 12h of the outer tube body 12. The contact area of the body 12 with the fitting insertion portion 12h can be widened, and higher sealing performance can be secured. In the present embodiment, the flange 11e is fitted to the inner peripheral surface of the outer tubular body 12 to ensure the sealing property between the inner tubular body 11 and the outer tubular body 12, but the flange 11e is placed outside. The sealability may be ensured by fixing (for example, ultrasonic welding) the tube 12.

  Thus, the pipe body 2 is configured as a double-structured pipe having the gap 15 between the outer pipe body 12 and the inner pipe body 11. The tube body 2 configured in this manner has the opening 2a (the opening 12e of the outer tube body 12) on one side in the axial direction, and the plug member 3 is fitted to the opening end 2b of the tube body 2. As a result, the opening 2a is closed.

  The stopper member 3 is a so-called rubber stopper and is made of, for example, synthetic rubber. The plug member 3 is formed in a substantially columnar shape, and the tip side portion 3 a thereof extends to the inner pipe body 11. Further, the proximal end portion 3b of the rubber plug projects outward from the open end 12f of the outer tubular body 12, and the proximal end portion 3b of the rubber plug has a flange 3c formed over the entire circumference thereof. Have The outer diameter of the flange 3c is formed to be larger than the outer diameter of the outer tube body 12, and when the opening 2a of the tube body 2 is closed by the plug member 3, it comes into contact with the opening end portion 12f of the outer tube body 12. It is like this. As a result, by contacting the open end portion 12f of the outer tubular body 12, expansion at the bottom portion can be prevented more easily than in the case where the contact is not made. The plug member 3 having such a shape seals the inside of the outer pipe body 12 in which the inner pipe body 11 is installed, and by sealing the gas and liquid in the inner pipe body 11 is not discharged to the outside. It has become.

  The double tube 1 thus configured has a vacuum inside the inner tube body 11 and is made vacuum by using a holder (not shown) with a blood sampling needle. There is. That is, the blood collection needle of the holder with the blood collection needle is punctured into the blood vessel, and then the double tube 1 is attached to the holder with the blood collection needle so that the blood in the blood vessel flows into the depressurized inner tube body 11. There is. Then, when an appropriate amount of blood is collected, the double tube 1 is removed from the holder with a blood collection needle. Thereby, the blood collected in the inner tube body 11 can be stored in a sealed state.

Further, the double tube 1 is frozen together with the blood in order to cryopreserve the collected blood. For example, when the collected blood is used for a genetic test, it may be stored for a long period of time, in which case the double-tube 1 is stored frozen with blood at −70 ° C. or lower. When blood is frozen, water contained in the blood starts to freeze at 0 ° C. or lower, and the blood starts to expand accordingly. The expanding water proceeds toward the plug member 3 in the inner tube 11, that is, to the upper side, and eventually the water on the upper side in the inner tube 11 is frozen first. As a result, the expansion of the water in the upper direction is gradually suppressed, and as a result, the expansion of the water in the blood transitions outward in the radial direction rather than in the axial direction. Therefore, the inner tube body 11 is subjected to expansion stress in the radial direction outward from the water in the blood that is about to expand. As the frozen portion of the water in the blood gets closer to the bottom side of the inner tube, the axial expansion becomes more difficult and the inner tube 11 is pushed outward in the radial direction, and the inner tube 11 is easily damaged. ..

  Further, the expansion stress of water in the blood does not uniformly act on the inner peripheral surface of the inner tube body 11, but its magnitude changes according to the inner diameter of the inner tube body 11. That is, the larger the inner diameter of the inner tube body 11, the smaller the expansion stress that acts, and the smaller the inner diameter, the larger the expansion stress that acts.

  Even in the bottom taper portion 11d, since it has a curved surface, it is difficult to deform in the vicinity of the bottom portion 11f having high rigidity, and the bottom side taper portion 11b is not deformed. It is likely to occur (see, for example, the deformation point 16 of the two-dot chain line in FIG. 4). Deformation due to the expansion of blood locally occurs at the bottom taper portion 11d of the inner tubular body 11, and the deformed portion 16 continues to expand according to the expansion of blood. Then, as the blood continues to expand, the deformed portion 16 eventually contacts the inner peripheral surface of the outer tubular body 12. After that, if the blood continues to expand, the outer tube body 12 is pushed radially outward by the deformed portion 16. As a result, the inner peripheral surface of the outer tubular body 12 may be deformed, but the deformed portion 16 can be separated from the flange 11e by generating the deformed portion 16 at the bottom taper portion 11d. As a result, it is possible to prevent the deformation portion 16 of the inner pipe body 11 from expanding and separating from the flange 11e and the fitting insertion portion 12h of the outer pipe body 12 so that the gap 15 communicates with the outside.

  Further, in the double pipe 1, the inner pipe body 11 is supported only by the opening end portion 11h (specifically, the flange 11e) and the bottom face 12d of the outer pipe body 12, and the inner pipe body 11 is opened in the outer pipe body 12. It is possible to swing in all radial directions with the end portion 11h as a base point. Further, in the double pipe 1, since the bottom surface 12d of the outer pipe body 12 is formed flat and the gap 15 between the bottom tapered portion 11d and the inner peripheral surface of the outer pipe body 12 is wide, the inner pipe body 11 is formed. The bottom portion 11f of the inner tube 11 can be slid on the bottom surface 12d, and the inner tube body 11 is not restricted in movement in any radial direction. Therefore, by generating the deformed portion 16 at the bottom taper portion 11d, even if the blood further expands in a state of hitting the inner peripheral surface of the outer tubular body 12, the inner tubular body 11 is moved in the opposite direction to the outer tubular body 12. Can be pushed back to. As a result, it is possible to prevent the outer tube body 12 from being deformed and damaged.

  Further, since the inner tubular body 11 can be pushed back to the side opposite to the direction in which the deformed portion 16 expands, it is possible to allow the blood to expand as much as it can be pushed back. That is, it is possible to allow the blood to expand by about twice the distance H of the gap 15. Therefore, as compared with the case where the inner tube body 11 is fixed in the outer tube body 12, it is possible to reduce the interval H of the gap 15 to allow the expansion of blood. Thereby, the outer dimensions of the double tube 1 can be suppressed.

  In the double tube 1, the blood may largely expand in the radial direction due to the freezing method of the blood, etc., and the deformed inner tube body 11 may not be able to endure and may be locally damaged. However, as described above, since the outer tube body 12 is not damaged, it is possible to prevent the blood from leaking from the double tube 1 even when the blood is thawed when it is used for a genetic test or the like.

  Further, in the double pipe 1, the flange 11e is fitted to the inner peripheral surface (fitting insertion portion 12h) of the outer pipe body 12 while the seal is achieved, and the flange 11e is inserted between the outer pipe body 12 and the inner pipe body 11. The gap 15 located at is closed. Since the gap 15 is sealed in this manner, even if the inner pipe body 11 is damaged, the blood in the inner pipe body 11 is unlikely to enter the gap 15 even if the inner pipe body 11 is connected to the gap 15. Therefore, it is possible to prevent the blood in the inner tubular body 11 from being drawn into the gap 15 due to the capillary phenomenon. As a result, the amount of blood that flows out into the gap 15 and cannot be taken out can be reduced, and it is possible to prevent a decrease in the amount of blood that can be used in an examination or the like. Further, even if it flows in, since the interval H of the gap 15 is small, it is possible to suppress the amount of blood that flows out into the gap 15 and cannot be taken out.

  Further, in the double pipe 1, since the gap 15 is sealed, even if the inner pipe body 11 is damaged and the inside of the inner pipe body 11 and the gap 15 are connected, the gap 15 becomes a negative pressure when the cap is opened. It is possible to suppress the outside air (air) from flowing into 15. As a result, the air that has flowed into the gap 15 does not enter the inside of the inner tube 11 through the damaged portion. This prevents bubbles from being generated in the inner tube body 11 at the time of opening the cap, and the bubbles from bursting and the blood to be scattered.

  Furthermore, in the double pipe 1, since the intermediate taper portion 11b having a larger gradient than the gradient between the opening side taper portion 11c and the bottom side taper portion 11d is formed, the opening side taper portion 11c and the bottom portion. The difference in outer diameter from the side taper portion 11d can be increased. This makes it possible to increase the outer diameter of the opening-side tapered portion 11c and reduce the expansion stress acting on the opening-side tapered portion 11c, while increasing the interval H of the gap 15 around the bottom-side tapered portion 11d.

  The inner tube body 11 and the outer tube body 12 are formed such that the interval H between the inner peripheral surface of the outer tube body 12 and the outer peripheral surface of the bottom taper portion 11d is 0.5 mm ≦ H ≦ 1.0 mm. ing. When the interval H is less than 0.5 mm, the outer tube 12 may be damaged due to the gap 15 not being able to absorb the expansion of the deformed portion 16, and when it is 1.0 mm or more, the deformed portion 16 locally expands. There is a case where the deformed portion 16 is damaged due to overdoing. In view of the above, the distance H between the inner peripheral surface of the outer tubular body 12 and the outer peripheral surface of the bottom taper portion 11d is 0.1 mm ≦ H ≦ 2.5 mm, preferably 0.5 mm ≦ H ≦ 1. It is preferably within the range of 0.0 mm.

  In a tube for storing a sample such as the double tube 1, the outer diameter dimension of the outer tube body 12 is predetermined so as to be attached to an inspection device or the like. Even when the gap 15 is provided, it is not an exception, and it is difficult to increase the outer diameter of the outer tube body 12 of the double tube 1. Therefore, in order to secure the gap 15, it is necessary to reduce the outer diameter of the inner pipe body 11. When the inner pipe body 11 and the outer pipe body 12 are straight pipes, the inner pipe body for bringing the open end portion 12e of the outer pipe body 12 and the open end portion 11h of the inner pipe body 11 into contact with each other so as to seal the gap 15. It is necessary to make the outer diameter of 11 and the inner diameter of the outer tubular body 12 about the same. Then, it becomes difficult to secure the gap 15 that allows the expansion. On the other hand, when the outer diameter of the inner tube body 11 is small, the gap 15 is widened, so that the heat insulating property is improved and the freezing of water in the blood is delayed. In view of these, by setting the interval H between the inner peripheral surface of the outer tubular body 12 and the outer peripheral surface of the bottom taper portion 11d to be in the above range, the inner tubular body 11 is expanded due to the expansion of water in blood. The gap 15 can be secured to allow the expansion, and at the same time, the slowing of the freezing rate of the water in the blood inside the inner tube body 11 can be suppressed.

  In the double pipe 1 thus configured, for example, the inner pipe body 11 is made of PE and the outer pipe body 12 is made of PET. That is, the material of the inner tube body 11 has a lower glass transition point than the material of the outer tube body 12, and the viscosity of the inner tube body 11 is smaller than the viscosity of the outer tube body 12. Therefore, the inner tube body 12 is more easily stretched and is less likely to be damaged than the outer tube body 11, and it is possible to further prevent the outer tube body 12 from being damaged when the blood is expanded.

<Other embodiments>
The double tube 1 of the present embodiment was used as a blood collection tube for collecting blood, but the sample to be collected is not limited to blood. The sample to be collected may be, for example, digestive fluid such as saliva and gastric juice, or secretory fluid such as sweat.

  Further, in the inner pipe body 11, the opening side taper portion 11c and the bottom side taper portion 11d are formed on both sides in the axial direction of the intermediate taper portion 11b, but the axial direction both sides of the intermediate taper portion 11b need not necessarily be tapered. There is no. It suffices that the outer diameters of both sides of the intermediate tapered portion 11b in the axial direction are different, and both sides of the intermediate tapered portion 11b in the axial direction may be formed substantially straight. Further, by forming the intermediate tapered portion 11b at the intermediate portion of the inner tubular body 11, the outer diameter of the inner tubular body 11 can be smoothly changed, so that stress concentration can be prevented, but it is not always necessary. The intermediate tapered portion 11b is not necessary, and a step may be formed in the intermediate portion of the cylindrical portion 11a so that the outer diameters of the opening side and the bottom side of the cylindrical portion 11a are different. When forming a step, it is preferable that the step has an R shape in order to improve durability against stress.

  Further, the inner tube body 11 does not necessarily have to be lower than the outer tube body 12 and may have the same height as the outer tube body 12. In the case of such an embodiment, the flange 11e of the inner pipe body 11 is fitted into the open end portion 12f of the outer pipe body 12. The double pipe of this embodiment also has the same effect as the double pipe 1 of the present embodiment. Further, the lower surface 11g of the inner tubular body 11 does not necessarily have to be concave around the axis L1 and may be flat or spherical.

DESCRIPTION OF SYMBOLS 1 Double tube 3 Plug member 11 Inner tube body 11b Intermediate taper part 11c Opening side taper part 11d Bottom side taper part 11g Lower surface 11h Opening end part 12 Outer tube body 12d Bottom surface 12h Fitting part 15 Gap

Claims (7)

A double tube for storing the collected sample and a bottomed inner tube for storing the collected sample,
A bottomed outer tube body that is attached to the inner tube body such that the inner tube body is inserted so as to form a gap between the inner tube body and the opening side of the gap is sealed;
A plug member for sealing the inside of the inner tubular body,
The lower surface of the inner tube slidably contacts the bottom surface of the outer tube,
The inner tube is a double tube in which the diameter of the bottom side is smaller than that of the opening side of the inner tube. The inner tubular body has an intermediate tapered portion at its axially intermediate portion,
The double pipe according to claim 1, wherein the intermediate tapered portion is reduced in diameter toward the bottom side of the inner pipe body. The inner tubular body has a bottom taper portion formed on the bottom side of the middle taper portion, and an opening side taper portion formed on the opening side of the middle taper portion,
The bottom side tapered portion and the opening side tapered portion expand in diameter from the bottom side of the inner tubular body toward the opening side,
The double pipe according to claim 2, wherein the slopes of the bottom taper portion and the opening taper portion are smaller than the slope of the intermediate taper portion.   The double pipe according to claim 3, wherein the gap between the bottom-side tapered portion of the inner pipe body and the outer pipe body is 0.1 mm or more and 2.5 mm or less.   The double pipe according to claim 4, wherein the gap between the bottom-side tapered portion of the inner pipe body and the outer pipe body is 0.5 mm or more and 1.0 mm or less. The outer peripheral surface of the opening end portion of the inner tubular body is formed substantially straight along the axis thereof, and is fitted in a state in which the inner peripheral surface of the outer tubular body is in close contact with the fitting portion.
The double pipe according to any one of claims 1 to 4, wherein the fitting portion is formed substantially straight along an axis of the outer pipe body. The outer tube and the inner tube are made of a resin material,
The double tube according to any one of claims 1 to 5, wherein the resin material of the inner tube body is a resin material having a glass transition point lower than that of the resin material of the outer tube body.

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