JP3166383U - Specimen collection device - Google Patents

Abstract

Provided is a specimen collecting apparatus that can cut a core from a surface layer to a subbase or a part of a surface layer to a part of a roadbed with a simple device while suppressing disturbance. The motor includes a cylindrical outer tube that is rotated by applying a driving force from a motor, and an inner tube that is inserted into the outer tube and supported so as to block transmission of the rotational force of the outer tube. A bit 22 is attached to the tip of an outer tube 21 which is an outer tube, and the bit 22 is lowered while rotating to cut the pavement into a columnar shape. The inner tube is composed of an inner tube 24, an outer extension tube 25, and an inner extension tube 26. The inner tube accommodates a core cut inside and is extracted from the pavement. In addition, by flowing the viscous liquid on the peripheral surface of the bit, the liquid permeates between the particles of the core to suppress disturbance of the core. Further, the core is covered and protected by a covering member 51 housed inside the inner tube. [Selection diagram] FIG.

Description

  The present invention relates to a specimen collection device that collects a pavement such as a road or a part of a pavement and a roadbed as a specimen for inspection.

  A pavement formed to use the upper surface as a road or the like is constructed by forming a roadbed in which crushed stones are compacted on a roadbed and laying a base layer and a surface layer made of asphalt mixture or concrete on the roadbed. In addition, an intermediate layer is provided between the base layer and the surface layer or the roadbed is divided into a plurality of layers according to the use and the magnitude and frequency of the load acting on the road surface. And a part or all of a roadbed may be stabilized by cement or a bitumen material. Such a pavement may need to be inspected for its thickness or compacted state as designed after laying. Moreover, about the pavement already laid, the state and structure of the present pavement may be grasped | ascertained by inspection, and appropriate repair etc. may be examined.

In order to inspect such a pavement, a part of the pavement is collected as a specimen for inspection. For example, Patent Document 1 or Patent Document 2 discloses a part of an existing asphalt pavement. Is described as a core.
In the core sampling method described in Patent Document 1, a cylindrical core bit is attached to the tip of an electric drill, and the core bit is rotated to cut a paved surface, and then extracted.
The core collection method described in Patent Document 2 is to place dry ice on an asphalt pavement from which a core is collected, and cut the pavement while cooling the pavement and the core bit.

JP 09-100691 A JP 2004-137682 A

The conventional core sampling method as described above is mainly intended to cut and remove the surface layer and base layer of the pavement solidified with asphalt mixture or concrete, etc., and the crushed stone with adjusted particle size is compacted. It is difficult to inspect the condition of the roadbed or roadbed. That is, the roadbed material or the soil forming the roadbed has a weak binding force between the particles and is difficult to extract in a state close to the laid state.
For this reason, in order to inspect the condition of the roadbed and the roadbed, a method has been adopted in which a hole having a planar shape of about 50 cm × 100 cm is cut and dug down to the position of the roadbed, and the state of the roadbed and the roadbed is observed. Yes.

However, although this method can know the state of the pavement, it takes a lot of time and labor to dig a large hole and dig it down to the position of the roadbed, and it takes time to refill the hole. For this reason, there exists a problem that cost becomes large.
There is also a problem that the traffic must be blocked for a long time in order to perform the work as described above.

  The present invention has been made in view of such circumstances, and the purpose thereof is a simple device that collects a specimen from a surface layer to a roadbed or a roadbed, and can be extracted in a state where disturbance is suppressed. Is to provide a device.

  In order to solve the above-mentioned problems, the device according to claim 1 is constructed such that a support base that is constructed on a roadbed and is installed on an upper surface of a pavement including at least a surface layer and a roadbed, and rotates about a vertical axis. The pavement body or a part of the pavement body and the road bed is cut into a cylindrical shape and cut as a specimen, a driving unit for applying a rotational driving force to the cutting unit, and a support base. A specimen collection device provided with a support column that supports the drive unit and the cutting unit so that the drive unit and the cutting unit can be moved up and down. A cylindrical outer tube that rotates, and an inner tube that is inserted into the outer tube and supported so that transmission of the rotational driving force from the drive unit is interrupted, and at the tip of the outer tube, A cutting blade for cutting the pavement into a cylindrical shape is mounted, and the inner pipe is Ri fringed by holding the specimen inwardly to provide a specimen collection device is intended to withdraw from the pavement.

In this specimen collection device, the driving force from the drive unit is transmitted, the cutting blade rotates together with the outer tube, and the cylindrical specimen can be cut from the pavement by the cutting blade. The specimen cut off as the cutting progresses is accommodated inside the inner tube that is inserted into the outer tube and does not rotate, and can be extracted from the pavement together with the inner tube. Therefore, the pavement or the pavement and a part of the roadbed are hardly disturbed by the cutting, and it is possible to collect the pavement and the pavement and a part of the roadbed near the state before the cutting.
The pavement may include all of the lower layer roadbed, the upper layer roadbed, the base layer laid on the roadbed, the intermediate layer, and the base layer, or may not include a part other than the surface layer. . Moreover, layers other than those described above may be included.

  The invention according to claim 2 is the specimen collection device according to claim 1, wherein the outer tube is capable of adjusting the rotation speed, and when cutting the roadbed or the roadbed, concrete or asphalt The surface layer made of concrete, the intermediate layer formed on the lower side of the surface layer, or the base layer is rotated at a lower speed than when cutting.

  The cutting blade of this specimen collection device rotates at a high speed when cutting a surface layer, an intermediate layer or a base layer laid in a state solidified with concrete or asphalt, and can be cut out in a short time. Moreover, when cutting a roadbed or a roadbed in which crushed stones or the like are compacted, it can be extracted at a low rotation speed while suppressing disturbance.

  The invention according to claim 3 is the specimen collection device according to claim 1 or 2, wherein a viscous fluid containing a polymer is poured into the cutting portion from between the outer tube and the inner tube. .

  In this specimen collection device, the poured viscous fluid permeates between particles of the roadbed material or the roadbed material before being cut off and after being cut off, thereby suppressing disturbance. Thereby, it becomes possible to extract the test piece in a state with little disturbance from the roadbed or the roadbed. Further, friction between the outer tube or the cutting blade and the pavement is reduced, and smooth cutting is possible.

  The invention according to claim 4 is the specimen collection device according to any one of claims 1 to 3, wherein the inner tube has an annular space between the outer peripheral surface and the inner peripheral surface, A cylindrical covering member having flexibility is accommodated in the space, and the covering member accommodates the cut specimen in a cylindrical shape.

  In this specimen collection device, the cut specimen is covered with the covering member and accommodated in the inner pipe, and can be taken out from the inner pipe in the covered state. This makes it possible to protect the specimen and suppress disturbance not only when it is housed in the inner pipe but also when it is taken out from the inner pipe and after it is taken out.

  As described above, in the specimen collection device according to the present invention, a part of the pavement can be cut as a specimen for inspection while suppressing disturbance.

It is a schematic side view showing a specimen collection device which is an embodiment of the present invention. It is a disassembled perspective view of the cutting part of the specimen collection apparatus shown in FIG. It is a schematic sectional drawing which shows the rear part of the cutting part shown in FIG. It is a schematic sectional drawing which shows the front-end | tip part of the cutting part shown in FIG. It is a schematic sectional drawing which shows an example of the pavement from which a specimen is extract | collected with the specimen collection apparatus shown in FIG.

FIG. 1 is a schematic side view showing a specimen collection device according to an embodiment of the present invention.
This specimen collection device is installed on the surface of the pavement 10 and cuts into a cylindrical shape from the surface layer of the pavement 10 to the roadbed or from the surface layer to a part of the roadbed. A device for cutting out a specimen (hereinafter referred to as “core”), which includes a support base 1, a support column 7 standing on the support base, a drive unit 8 supported by the support column 7, and a drive unit 8. The main part is constituted by the cutting part 20 that cuts off a part of the pavement 10 while being rotated with the rotational driving force applied.
The support base 1 is installed on the surface of the pavement 10 from which the core is removed. The base 2, the guide 3 for guiding the cutting unit 20 to enter the pavement 10, and the base 2 Height adjustment bolts 4 that are provided at the four corners of the base 2 to support and adjust the height of the base 2, wheels 5 that are used to travel the apparatus, and a frame body 6 that is gripped when the apparatus is moved. I have.

The base 2 is a trapezoidal member whose planar shape is substantially rectangular, and is formed of a steel frame and a plate attached on the steel frame.
The guide 3 is attached to the periphery of a hole provided so as to penetrate the base 2 in the vertical direction, restricts the position of the cutting portion 20 that rotates about the vertical axis, and the cutting portion 20 becomes the pavement 10. This guides the user to descend almost vertically.
The height adjusting bolt 4 includes a pressure bearing plate 4a on the side in contact with the pavement surface, and each can independently adjust the height of the base 2 with respect to the pavement surface. Accordingly, the base 2 can be installed almost horizontally even on an inclined pavement surface. The wheel 5 is provided on the lower surface of the base 2 and can be transported by running the apparatus.
When the support base 1 is installed on the pavement surface, the height adjusting bolt 4 protrudes below the base 2 longer than the height of the wheel 5 and supports the bearing plate 4a in contact with the pavement surface. The base 1 is supported. On the other hand, when conveying an apparatus, contact | abutting with the bearing plate 4a and a pavement surface is cancelled | released, and the wheel 5 is made to contact a pavement surface.

The support column 7 is supported by the support base 1 and is erected substantially vertically, and a rack gear 7a is provided on a side surface.
The driving unit 8 includes an elevating unit 41 that is mounted on the support column 7 and is movable in the vertical direction, and a motor unit 42 supported by the elevating unit 41.
The elevating part 41 includes a pinion gear (not shown) meshed with the rack gear 7a and an elevating handle 43, and the pinion gear rotates by rotating the elevating handle 43. . Accordingly, the operation of rotating the handle 43 causes the elevating part 41 to move up and down along the support column 7 together with the motor unit 42.
The motor unit 42 includes a motor 44 and a reduction gear (not shown), and rotationally drives a drive shaft 45 connected to the cutting unit 20 around the axis. The rotational speed of the motor 44 can be changed in two or more steps, and a changeover switch (not shown) for switching the rotational speed is provided. Further, the drive shaft 45 that is rotationally driven by the motor 44 is hollow, and the liquid supplied from the liquid supply port 46 provided in the motor unit 42 is introduced into the hollow portion of the drive shaft 45, and this drive shaft 45. It can supply to the cutting part 20 connected to.

  The cutting unit 20 is connected to the drive shaft 45 of the motor unit 42 and is supported so that the axis is in a substantially vertical direction. Then, the rotational drive force is transmitted from the drive shaft 45 and moves downward together with the drive unit 8. Therefore, the tip portion is guided toward the pavement 10 by being guided by the guide 3 supported by the base 2 and enters the pavement while cutting the pavement 10.

FIG. 2 is an exploded perspective view of the cutting unit 20. 3 is a cross-sectional view showing the rear part of the cutting part 20, and FIG. 4 is a cross-sectional view of the tip part.
The cutting unit 20 is connected to the drive shaft 45 of the motor unit 42 and is given a rotational driving force, and the cylindrical outer tube 21 connected to the swivel head 30 and functions as an outer tube. A bit 22 as a cutting blade attached to the tip of the outer tube 21, a cylindrical inner tube 24 that functions as an inner tube with a gap inserted inside the outer tube 21, an outer extension tube 25, and an inner tube An extension tube 26, a core lifter 27 that holds the cut core, and a core that is attached to the tip where the inner tube 24, the outer extension tube 25, and the inner extension tube 26 are connected to hold the core lifter 27 inside. Lifter case 28 and In the main portion is configured.

As shown in FIGS. 2 and 3, the swivel head 30 includes a cylindrical outer tube head 31, an inner tube head 32 having an outer diameter smaller than the outer tube head 31, and the outer tube head 31 and the inner tube head. And a hollow shaft 33 that couples to the shaft 32.
The outer tube head 31 has a female screw 31b formed at its rear end, and a hollow drive shaft 45 is screwed and joined to the female screw 31b. A rotational driving force is applied from the drive shaft 45 so that the outer tube head 31 rotates about the central axis in the vertical direction.
The shaft 33 is fixed to the inner tube head 32 and supported by the outer tube head 31 via bearings 34 and 35 (bearings). Thereby, the transmission of the rotational driving force of the shaft 33 is interrupted, and the inner tube head 32 does not rotate even when the outer tube head 31 is rotationally driven.

The outer tube 21 is a hollow cylindrical member, and a female screw (not shown) formed on the inner peripheral surface of the rear end portion and a male screw 31a formed on the outer peripheral surface of the outer tube head 31 are screwed. Combined and supported by the outer tube head 31. Therefore, it rotates around the central axis along with the outer tube head 31.
The bit 22 is a substantially cylindrical member, and a male screw 22 a formed on the outer peripheral surface of the rear end portion is screwed into a female screw 21 a formed on the inner peripheral surface of the outer tube 21 and attached to the tip of the outer tube 21. ing. Therefore, the bit 22 rotates around the central axis together with the outer tube 21.
Further, a metal chip 22b made of titanium carbide or the like is embedded in the front end surface of the bit 22 so as to protrude. The metal chip 22b of the bit 22 descending while rotating with the lowering of the motor unit 42 comes into contact with the pavement 10, and the pavement 10 can be cut to cut the core into a cylindrical shape.
In the present embodiment, the inner diameter of the bit 22 is about 8 cm.

  As shown in FIGS. 2 and 3, the inner tube 24 is screwed to a male screw 32 a formed at the distal end portion of the inner tube head 32, so that the rotational driving force from the motor 44 is not transmitted. An outer extension tube 25 is twisted and connected to the distal end side of the inner tube 24 so as to extend the outer peripheral surface. An inner extension tube 26 is accommodated inside the outer extension tube 25 with a space therebetween, and a female screw 25 a provided at the distal end of the outer extension tube 25 expands the outer diameter on the distal end side of the inner extension tube 26. And are joined by being screwed to a male screw 26a provided in the portion. Therefore, an annular space is formed between the inner peripheral surface of the outer extension tube 25 and the outer peripheral surface of the inner extension tube 26, and this space is sealed on the tip side and opened on the rear side. A core lifter case 28 holding the core lifter 27 inside is twisted and attached to the male screw 26b provided at the tip of the inner extension tube 26.

In the annular space formed between the outer extension tube 25 and the inner extension tube 26, a covering member 51 that covers the core is accommodated in a bellows-like manner with its length contracted. Further, the rear end portion of the covering member 51 is drawn out of a gap formed between the inner extension tube 26 and the outer extension tube 25, and is a short cylindrical shape held inside the inner extension tube 26. Fastened to the locking device 52. A circumferential recess 52a is formed on the outer peripheral surface of the locking device 52, and the covering member 51 covers the recess, and is fastened by wrapping an elastic member 53 such as a rubber band from the outside.
As the covering member 51, a cylindrical transparent film made of a synthetic resin having flexibility is used in the present embodiment, but a space formed between the outer extension tube 25 and the inner extension tube 26. Any other material can be used as long as it can be housed and can protect the core. For example, a net-like member made of synthetic resin or the like may be used.

The core lifter 27 is a member that is tightened so as to surround the periphery of the core that is cut into a cylindrical shape by the bit 22, and is formed of a material having elasticity such as steel. And it is discontinuous at one place in the circumferential direction, is pushed down from above around the core cut out in a columnar shape, and holds the core by tightening the periphery of the core with elastic force.
The core lifter case 28 is a substantially cylindrical member that accommodates the core lifter 27 inside. When the cutting progresses and descends with the bit 22, the core lifter case 28 is locked to the rear end portion of the core lifter 27 and moves the core lifter 27 downward. Can be pushed down. Further, when the cutting is finished and the cutting part 20 is pulled up, the core lifter 27 is locked to the core lifter case 28 and the core that is held so that the core lifter 27 is tightened can be pulled up.

As described above, the outer tube 21 and the bit 22 connected to the outer tube head 31 of the swivel head 30, the inner tube 24, the outer extension tube 25, the inner extension tube 26, and the core lifter connected to the inner tube head 32. An annular gap is formed between the case 28 and the case 28. The outer tube 21 and the bit 22 are rotated by the rotational driving force around the vertical axis transmitted from the outer tube head 31, and the inner tube from which the rotational force is blocked is transmitted from the inner tube 24 to the core lifter case 28. It is connected to the head 32 and descends with the progress of cutting by the bit 22 without rotating. The viscous fluid sent from the liquid supply port 46 of the motor unit 42 is supplied to the gap between the outer tube 21 and the inner tube 24. This viscous fluid is sent from the hollow drive shaft 45 to the shaft 33 which is the hollow of the swivel head. The shaft 33 is provided with a small hole 33a between a portion supported by the outer tube head 31 and a portion supporting the inner tube head 32, and the viscous fluid flows out of the small hole 33a and It flows down between the inner tubes 24. And it supplies to the part which is cutting the pavement 10 by the bit 22.
In addition, the viscous fluid can use the liquid which has a polymer as a main component, for example. As an example of a liquid containing a polymer as a main component, there is an aqueous solution of “Holler” (trade name) manufactured by Dainichi Sogyo Co., Ltd. Also, other liquids that can suppress the disturbance of the core can be used.

Next, a process of collecting a core using such a specimen collection device will be described.
In this specimen collection device, not only the layer solidified with asphalt or concrete such as the surface layer and base layer of the pavement 10, but also a part of the roadbed and roadbed can be cut and extracted as a core. For example, as shown in FIG. 5, asphalt pavement in which roadbeds 62 and 63 made of a plurality of layers are formed on a roadbed 61, and a base layer 64 made of an asphalt mixture, an intermediate layer 65, and a surface layer 66 are laid in that order. The core can be removed from.
The road bed 61 is constructed by sanding and solidifying, and has a thickness of about 100 cm. The above-mentioned roadbed is composed of a lower-layer roadbed 62 and an upper-layer roadbed 63, and is constructed by laying and solidifying crushed stone and slag whose particle size has been adjusted. The lower layer roadbed 62 has a thickness of about 20 cm, and the upper layer roadbed 63 has a thickness of about 20 cm. The base layer 64, the intermediate layer 65, and the surface layer 66 are made of an asphalt mixture, and each has a thickness of about 5 cm.

  In order to collect the core of the pavement 10 as described above, the specimen collection device is moved by the wheel 5 attached to the support base 1 and moved to a position where the core is collected. At this time, the drive unit 8 is raised to the upper part of the support column 7 so that the cutting unit 20 is supported at a position away from the surface of the pavement 10. At the position where the core is collected, the support plate 4a of the four height adjustment bolts 4 is brought into contact with the surface of the pavement 10, and the height of each height adjustment bolt 4 is adjusted so that the base 2 is substantially horizontal. Install so that. After confirming that the base 2 of the specimen collection device is installed horizontally, the handle 43 is slowly rotated to lower the cutting unit 20 together with the motor unit 42. At this time, the outer tube 21 is guided by the guide 3 provided on the base 2, and the bit 22 descends in a substantially vertical direction toward the surface of the pavement 10.

When the bit 22 reaches the surface of the pavement 10, the motor 44 is driven and the supply of the viscous fluid is started from the liquid supply port 46, and the cutting unit 20 is slowly lowered while turning the handle 43. At this time, the outer tube 21 and the bit 22 are lowered while rotating around the axis, and the bit 22 cuts the pavement 10 into a cylindrical shape.
At the start of cutting, the rotation speed of the motor 44 is increased by a changeover switch (not shown) to cut the asphalt layer, that is, the surface layer 66, the intermediate layer 65, and the base layer 64. When the bit 22 reaches the upper layer roadbed 63, the motor 44 is switched to low speed rotation, and the upper layer roadbed 63, the lower layer roadbed 62, and the road bed 61 are cut continuously.

In this way, the layer solidified by asphalt is cut by rotating the bit 22 at a high speed, and the layer such as the roadbed that has just been compacted is cut at a low speed, so that the cutting time can be shortened and the core that has been cut Can be prevented.
In addition, since the cutting is performed while the viscous fluid is poured into the peripheral surface of the bit 22, the bit 22 that is at a high temperature at the time of cutting is cooled, and the viscous liquid penetrates into the core particles to be cut to suppress the disturbance of the core. Can do.

As the bit 22 digs up the pavement, the core cut into a cylindrical shape enters the non-rotating core lifter 27, and from the inside of the core lifter case 28 to the inside of the inner extension tube 26, the inner tube. Enter inside 24. Then, the upper end of the core is abutted against the locking device 52 and pushes up the locking device 52. Accordingly, the covering member 51 fastened to the locking device 52 is pulled out from the gap between the inner extension tube 26 and the outer extension tube 25 to cover the core. Therefore, it is possible to cover the core in a state close to the present state of being laid with the covering member 51 and accommodate the core inside the inner tube 24 or the inner extension tube 26.
The cut core can accommodate the length until the locking device 52 reaches the tip 33b of the shaft 33 in the inner tube 24. In the present embodiment, the core can be accommodated. Is approximately 74 cm.

When the bit 22 enters to a predetermined depth and the core to be collected is accommodated in the inner tube 24 or the inner extension tube 26, the rotation of the motor 44 is stopped and the supply of the viscous liquid is stopped. Then, the handle 43 is reversely rotated to lift the cutting unit 20 together with the drive unit 8. At this time, the core lifter 27 attached to the inside of the core lifter case 28 tightens and holds the lower end portion of the core, and the core is accommodated inside the inner extension tube 26 or the inner tube 24 and lifted on the pavement surface. It is done.
The pulled cutting portion 20 is removed from the motor unit 42, and the outer tube 21 and the inner tube 24 are removed from the swivel head 30. Then, the core covered with the covering member 51 is taken out from the inner tube 24, and the collection of the core is completed.
In this specimen collection device, a core having a diameter of about 8 cm and a length of about 74 cm can be collected, so that even a part of the road bed 61 can be collected.

In addition, this invention is not limited to the above-mentioned embodiment, It can also be implemented as another form within the scope of the present invention.
For example, although a two-speed motor is used in the present embodiment, a three-speed or higher speed motor can be used. Further, instead of the configuration in which the operator switches the changeover switch to change the rotation speed of the bit, the control device may change the rotation speed based on a change in load when the bit cuts the pavement. Good.

Furthermore, in this embodiment, the core of the pavement having an asphalt mixture layer is collected. However, the pavement having a concrete layer and a pavement having a roadbed that has been stabilized by mixing asphalt, cement, lime, or the like. The core can also be collected.
In addition, the size of the cutting part, such as the diameter of the bit and the length of the inner tube, is not limited to the present embodiment, and other sizes can be used, and the structure of the swivel head and the core lifter can also be used. Other forms can be used within the scope of the invention.

1: support base, 2: base, 3: guide, 4: height adjustment bolt, 5: wheel, 6: frame, 7: support, 7a: rack gear, 8: drive unit, 10: pavement,
20: Cutting part, 21: Outer tube, 22: Bit, 24: Inner tube, 25: Outer extension tube, 26: Inner extension tube, 27: Core lifter, 28: Core lifter case,
31: Outer tube head, 32: Inner tube head, 33: Shaft, 34, 35: Bearing,
41: Lifting part, 42: Motor unit, 43: Handle, 44: Motor, 45: Drive shaft, 46: Fluid supply port,
51: Cover member, 52: Locking device, 53: Elastic member,
61: Road bed, 62: Lower road bed, 63: Upper road bed, 64: Base layer, 65: Middle layer, 66: Surface layer

Claims (4)

A support base constructed on the roadbed and installed on the upper surface of the pavement including at least the surface layer and the roadbed;
A cutting part that cuts the pavement or a part of the pavement and the road bed into a cylindrical shape while rotating around a substantially vertical axis, and cuts out as a specimen,
A drive unit for applying a rotational driving force to the cutting unit;
A specimen collection device provided with a column that is erected on the support base and supports the drive unit and the cutting unit so as to be movable up and down,
The cutting portion is inserted into the outer tube and a cylindrical outer tube that rotates around a central axis when a driving force is applied from the driving unit, and transmission of the rotational driving force from the driving unit is blocked. And an inner tube supported as
A cutting blade for cutting the pavement into a cylindrical shape is attached to the tip of the outer tube,
The specimen collection device according to claim 1, wherein the inner pipe holds the cut specimen and removes the specimen from the pavement. The outer tube is capable of adjusting the rotation speed,
When cutting the roadbed or the roadbed, the surface layer made of concrete or asphalt concrete, the intermediate layer formed on the lower side of the surface layer or the base layer is rotated at a lower speed than when cutting. The specimen collection device according to claim 1, wherein the specimen collection device is characterized.   The specimen collection device according to claim 1 or 2, wherein a viscous fluid containing a polymer is poured into the cutting portion from between the outer tube and the inner tube. The inner tube has an annular space between the outer peripheral surface and the inner peripheral surface,
A cylindrical covering member having flexibility is accommodated in the space,
The specimen collection device according to any one of claims 1 to 3, wherein the covering member accommodates the cut specimen in a cylindrical shape.

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