JP2021120506A - Screen tube - Google Patents

Abstract

To provide a screen tube arranged with a protective member for forming water passing slits on the outer periphery of a tube body having through-holes, suppressed in positional displacement between the tube body and the protective member.SOLUTION: A screen tube 1 comprises a cylindrical tube body 10, multiple through-holes 11 penetrating through the tube body 10 outward and inward, a resin protective member 20 arranged along an outer periphery of the tube body 10, and water passing slits 27 formed of the protective member 20. An additive agent is contained in the resin forming the protective member 20 for preventing expansion and shrinkage of the protective member 20 due to temperature change.SELECTED DRAWING: Figure 1

Description

The present invention relates to a screen tube used for constructing a well or the like.

Conventionally, when constructing a well, a pipe body called a screen pipe may be used. A well using a screen pipe is one in which one screen pipe or a plurality of screen pipes connected in the pipe axis direction are vertically buried in the ground and the upper end thereof is opened to the ground surface. .. Since the screen tube has a large number of through holes, a liquid such as water in the ground exudes into the tube through the through holes.

As the screen tube, for example, there are those described in Patent Documents 1 and 2. These screen tubes are provided with a large number of through holes in a tubular tube body, and protective members are arranged along the outer surface of the tube body so as to cover the through holes. The protective member forms a water passage slit that filters foreign matter such as sand from the liquid that enters the pipe. As the protective member, for example, a spiral wire is wound around the outer circumference of the pipe body, or a large number of rings are arranged in parallel along the pipe axis direction.

Japanese Unexamined Patent Publication No. 6-272285 Japanese Unexamined Patent Publication No. 2010-84388

The screen tube uses fiber reinforced resin (fiber reinforced plastic / FRP) or metal as the material of the tube body, and the material of the protective member is a general resin (for example, polypropylene, etc.) that is not a composite resin of fibers. ) Is often adopted. Many of the protective members have a relatively thin cross section in order to form a water passage slit, and there is a background that it is difficult to use a resin in which fibers are compounded in a member including such a portion.

Therefore, the amount of thermal expansion of the protective member tends to be larger than the amount of thermal expansion of the tube body due to the temperature change. If the difference in the amount of thermal expansion between the tube body and the protective member is large, it causes a positional shift between the tube body and the protective member, which is not preferable.

Therefore, an object of the present invention is to suppress a misalignment between the tube body and the protective member in a screen tube in which a protective member for forming a water passage slit is arranged on the outer periphery of the tube body provided with a through hole.

In order to solve the above problems, the present invention presents a tubular tube body, a plurality of through holes penetrating the tube body in and out, and a resin protection arranged along the outer surface of the tube body. A screen tube including a member and a water passage slit formed by the protective member, wherein the resin constituting the protective member contains an additive that suppresses expansion and contraction of the protective member due to a temperature change. It was adopted.

As the additive, for example, mica can be adopted.

Further, in order to solve the above problems, the present invention is made of a tubular tube body, a plurality of through holes penetrating the tube body inside and outside, and a resin arranged along the outer surface of the tube body. In the screen tube including the protective member of the above and the water passage slit formed by the protective member, the tube main body is provided with a cover portion facing the outer surface of the axial end portion of the protective member.

Further, it is possible to adopt a configuration in which the tube main body is provided with a stopper portion that comes into contact with the end surface of the axial end portion of the protective member, and the cover portion is provided so as to project inward in the axial direction from the stopper portion. ..

In a screen tube in which a protective member for forming a water passage slit is arranged on the outer periphery of a tube body provided with a through hole, it is possible to suppress a misalignment between the tube body and the protective member.

Overall front view showing an embodiment of the present invention II-II sectional view of FIG. III-III cross-sectional view of FIG. Enlarged view of the main part of FIG. Detailed view showing an example of a protective member

An embodiment of the present invention will be described with reference to the drawings. This embodiment is a screen tube 1 used when constructing a well. The screen tube 1 is usually buried in the ground in the vertical direction and is used in a state where the upper end thereof is opened to the ground surface, but it is considered that the screen tube 1 may be buried in the ground in the horizontal direction for other purposes. Be done. Since the screen tube 1 has a large number of through holes 11, a liquid such as water in the ground exudes into the tube through the through holes 11. The total length, diameter, cross-sectional shape, etc. of the screen tube 1 are appropriately set according to the application and specifications.

As shown in FIGS. 1 and 2, the screen tube 1 includes a tubular synthetic resin tube body 10, a synthetic resin protective member 20 arranged along the outer surface of the tube body 10, and a protective member 20 made of synthetic resin. It has accessories that can be attached to them. The tube body 10 is made of a fiber-reinforced resin tubular body.

A plurality of through holes 11 penetrating inside and outside are formed on the peripheral surface of the tubular body constituting the tube body 10. The through holes 11 may be provided over the entire peripheral surface of the tubular body, or as shown in FIG. 1, are provided in a part of the peripheral surface of the tubular body except for the vicinity of the pipe end. You may be.

The pipe body 10 is provided with a receiving port 2 at one end in the axial direction and an insertion port 3 at the other end in the axial direction. By inserting the insertion port 3 of another pipe body 10 into the receiving port 2 of one pipe body 10, it is possible to lay a plurality of pipe bodies 10 in a connected state. The receiving port 2 is composed of a fiber-reinforced resin joint member 4 attached to one end side of the tubular body in the axial direction as an accessory part. The insertion port 3 is integrally molded with the pipe body 10. However, since the form of the socket 2 and the insertion port 3 can be appropriately set according to the application and specifications, the socket 2 may be made of a member integrated with the pipe body 10, or the insertion port 3 may be separated from the pipe body 10. It may be composed of body members.

As shown in FIG. 1, the joint member 4 of this embodiment has a locking recess 2a on the inner surface of the tip portion 4b, and the rear end portion 4a is fixed to the pipe body 10 by a pin 5. Further, on the outer surface of the insertion port 3, a locking convex portion 3a that meshes with the locking recess 2a is provided. When the locking recess 2a meshes with the locking protrusion 3a, the pipe bodies 10 are watertightly connected to each other. In addition, packing for water stoppage (not shown) or the like is appropriately used together.

Further, the protective member 20 is arranged along the outer surface of the pipe body 10 so as to cover a large number of through holes 11 provided in the pipe body 10. In the protective member 20 of this embodiment, a large number of rings 21 are arranged in parallel along the pipe axis direction. As shown in FIGS. 2 and 5, the ring 21 is provided with connecting protrusions 21a and 21b on the surface on one end side in the axial direction and concave portions 21c and 21d on the surface on the other end side in the axial direction. By fitting the connecting protrusions 21a and 21b of one ring 21 into the connecting recesses 21c and 21d of the other adjacent rings 21, the rings 21 are connected to each other with a gap in the axial direction. ing. The water passage slit 27 is formed by the gap between the rings 21 adjacent to each other in the axial direction.

As shown in FIG. 1, the water passage slit 27 extends in the circumferential direction with a predetermined gap (for example, an interval of about 0.1 mm to 2 mm) in the portion exposed on the outer surface, and the gap extending in the circumferential direction is the axial direction. Multiple articles are arranged in parallel. Further, since the convex portion 21e is intermittently provided on the inner surface of the ring 21 along the circumferential direction, the convex portion 21e is in contact with the outer surface of the pipe body 10, and the other portion is the inner surface of the ring 21. A gap is interposed in the radial direction between the pipe body 10 and the outer surface of the pipe body 10. Through these gaps, the protective member 20 forms a water passage slit 27 that filters foreign matter such as sand from the liquid that invades the inside of the pipe body 10.

The end portion of the protective member 20 formed of a set of a large number of rings 21 on one end side in the axial direction is restrained by the stopper portion 23 fixed to the outer surface of the pipe body 10. As shown in FIGS. 3 and 4, the stopper portion 23 is an annular member fixed to the outer surface of the pipe body 10 by a pin 26. Further, the end portion of the protective member 20 on the other end side in the axial direction is restrained by the stopper portion 22 fixed to the outer surface of the pipe body 10. The stopper portion 22 is also an annular member fixed to the outer surface of the pipe body 10 with a pin. The protective member 20 is sandwiched between the inner end faces 22a and 23a of the stopper portions 22 and 23 and pushed in with pressure in the axial direction. Here, the axial movement of the protective member 20 is restricted by the axial end surfaces of the protective member 20 coming into contact with the inner end surfaces 22a, 23a of the stopper portions 22, 23. The fixing structure of the stopper portions 22 and 23 to the pipe body 10 is free, and in addition to the pin fixing as in this embodiment, press-fit fixing, adhesive fixing, welding fixing and the like may be used. Further, as a structure for fixing the stoppers 22 and 23 to the pipe body 10, the stoppers 22 and 23 and the pipe body 10 can be laminated and fixed with fibers and resin, and the stoppers 22 and 23 and the pipe body 10 can be fixed. It can also be integrally molded.

Further, the pipe body 10 includes a cover portion 24 facing the outer surface of the axial end portion of the protective member 20. By providing the cover portion 24, it is possible to prevent the outer surface of the tube body 10 from being exposed when the protective member 20 contracts due to a temperature drop. Even if the protective member 20 contracts in the pipe axis direction and a portion is formed on the outer surface of the pipe body 10 between the stopper portions 22 and 23 that is not covered by the protective member 20, that portion is covered by the cover portion 24. Because there is. When the through holes 11 are located near the stopper portions 22 and 23, the exposure of the through holes 11 can be prevented by setting the protruding length of the cover portion 24 to an appropriate length.

In this embodiment, the cover portion 24 is provided only on the one end side in the axial direction, which is the receiving port 2, but the cover portion 24 may be provided on the other end side in the axial direction, which is the insertion port 3 side. When laying the pipe body 10 in the vertical direction, it is desirable to cover the end portion on the upper side of the protective member 20 with the cover portion 24. Therefore, usually, the protective member 20 is used as in the embodiment. The cover portion 24 is set only at the end portion on the receiving port 2 side of the above. The length of the cover portion 24 is determined by considering the amount of expansion and contraction of the protective member 20 in the axial direction from conditions such as the annual temperature difference at the laying location of the pipe body 10, and the axial end portion of the protective member 20 is the cover portion 24. It is desirable to set it so that it is always covered by.

Further, in this embodiment, the cover portion 24 is provided so as to project inward in the axial direction from the stopper portions 22 and 23. Specifically, as shown in FIG. 4, a cover portion 24 made of a member different from the stopper portion 23 is fixed to the outer surface of the stopper portion 23 by a pin 25. Therefore, by fixing the cover portion 24 after attaching the protective member 20 between the stopper portions 22 and 23, the members can be easily assembled. The same structure can be used when the cover portion 24 is provided on the insertion port 3 side. Further, the structure for fixing the cover portion 24 to the stopper portions 22 and 23 is free, and in addition to the pin fixing as in this embodiment, press-fit fixing, adhesive fixing, welding fixing and the like may be performed. Further, the cover portion 24 and the stopper portions 22 and 23 may be integrated members.

As the material of the protective member 20, polypropylene or the like is adopted as a general resin that is not a resin in which fibers are composited. Further, to the resin constituting the protective member 20, an additive that suppresses expansion and contraction of the protective member 20 due to a temperature change, that is, an additive that suppresses thermal expansion and contraction (expansion when the temperature rises and shrinkage when the temperature drops) is added. Contains the agent. In this embodiment, mica (mica) is used as an additive. Mica is a material that hardly expands by itself and has a smaller coefficient of thermal expansion than the base resin. By including a material having a small amount of volume change due to temperature in the resin, expansion and contraction due to the temperature change of the resin itself can be suppressed. As a result, it is possible to reduce the difference in the coefficient of thermal expansion between the pipe body 10 and the protective member 20 and prevent the position shift between the pipe body 10 and the protective member 20. The coefficient of thermal expansion indicates the rate at which the length or volume of an object expands due to an increase in temperature per unit temperature, and is also called the coefficient of thermal expansion. On the contrary, when the temperature drops, the length and volume of the object shrink at that rate. As the base resin containing the additive, in addition to the polypropylene-based resin as described above, for example, a polyethylene-based resin or a polyolefin-based resin can be adopted.

As for the content of mica, good results have been confirmed when the weight content of mica is 10% or more and 50% or less with respect to the total weight of the resin and mica. In particular, better results are obtained when the weight content of mica is 20% or more and 30% or less, and the median value of 25% is optimal. It is considered that the effect is obtained even if the polymerization compounding ratio of mica exceeds 50%, but 50% or less is desirable because the viscosity of the resin becomes high and the moldability deteriorates. Further, even if the polymerization content of mica is less than 10%, it is considered to be effective as long as it contains mica, but it is practical to set it to 10% or more. By adopting mica as an additive, when the additive is mixed with the resin to form the protective member 20, the smoothness of the mold (mandrel) is maintained by the polishing action of mica, and the accuracy of the mold is maintained. Can be expected to have the effect of connecting.

Further, in this embodiment, the fiber reinforced resin is used as the material of the pipe body 10, but other resins, metals and the like may be used in addition to the fiber reinforced resin. Further, in this embodiment, mica is used as an additive to be contained in the protective member 20, but in addition to this, a material having a smaller coefficient of thermal expansion than the base resin, for example, glass fiber powder, is used. You may. The additive is preferably a powder material so that it can penetrate into a portion having a relatively narrow cross section constituting the protective member 20.

In the above embodiment, the resin constituting the protective member 20 contains an additive that suppresses expansion and contraction of the protective member 20 due to a temperature change, and the tube body 10 contains the protective member 20. Although the second configuration including the cover portion 24 facing the outer surface of the axial end portion of the above is used in combination, the effect of the present invention is expected even if the first configuration and the second configuration are selectively adopted. can. Therefore, the effect of the present invention can be expected even if the configuration includes only the first configuration or the configuration including only the second configuration.

Further, in the above embodiment, a plurality of rings 21 are connected in the axial direction as the protective member 20, but in addition to this, a spiral wire or the like spirally wound along the outer surface of the pipe body 10 is used. It may be adopted.

1 Screen pipe 2 Receiving port 3 Insertion port 4 Joint member 10 Pipe body 11 Through hole 20 Protective member 22, 23 Stopper part 24 Cover part 27 Water flow slit

Claims (4)

The tubular tube body (10) and
A plurality of through holes (11) penetrating the inside and outside of the pipe body (10),
A resin protective member (20) arranged along the outer surface of the pipe body (10), and
A water passage slit (27) formed by the protective member (20) and
In a screen tube equipped with
A screen tube characterized in that the resin constituting the protective member (20) contains an additive that suppresses expansion and contraction of the protective member (20) due to a temperature change. The screen tube according to claim 1, wherein the additive is mica. The tubular tube body (10) and
A plurality of through holes (11) penetrating the inside and outside of the pipe body (10),
A resin protective member (20) arranged along the outer surface of the pipe body (10), and
A water passage slit (27) formed by the protective member (20) and
In a screen tube equipped with
A screen tube characterized in that the tube body (10) is provided with a cover portion (24) facing the outer surface of an axial end portion of the protective member (20). The pipe body (10) is provided with stopper portions (22, 23) that come into contact with the end faces of the axial end portions of the protective member (20).
The screen tube according to claim 3, wherein the cover portion (24) is provided so as to project inward in the axial direction from the stopper portions (22, 23).

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