JPS6316210B2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Classification/Field> The disclosed technology belongs to the technical field of manufacturing corrosion-resistant double pipes such as oil country tubular goods by hydraulic pipe expansion.

<Explanation of the gist> Accordingly, the present invention has an outer tube and an inner tube relatively layered, one end of the inner tube is liquid-tightly sealed with a fixed seal and an actuator corresponding to the fixed seal, and on the other hand, The other end of the inner tube is similarly liquid-tightly sealed by a movable seal and a corresponding clamp seal, and a tube expansion liquid is supplied from a tube expansion flow passage formed in either the fixed seal or the movable seal. hand,
This invention relates to a double pipe manufacturing device in which an inner pipe is hydraulically expanded and integrated with an outer pipe, and in particular, a core metal is provided inside the inner pipe that is layered relative to the outer pipe, and the tip is attached to the inner pipe. A double pipe is provided with a fixed seal, and an expansion flow passage is provided inside to communicate with a tube expansion chamber formed on the outer peripheral surface of the pipe, and a clamp seal corresponding to the fixed seal is provided with an actuator for operating the clamp seal. This invention relates to a manufacturing device.

<Prior Art> As is well-known, double-walled oil country tubular goods are widely used, with pressure-resistant outer pipe and corrosion-resistant inner pipe, in order to have functions such as pressure resistance and corrosion resistance. From the viewpoint of ease of use and cost, many applicants have developed and proposed new technologies for non-metallurgical bonding, such as the thermal tube expansion method, which were filed as prior inventions, and are now being adopted. .

Therefore, the pipe expansion method used in the thermal pipe expansion method includes the so-called
Hydraulic tube expansion technology is adopted.

There are various types of double-pipe manufacturing equipment in which the inner tube is relatively stacked on the outer tube, the tube expansion liquid is fed into the inner tube to apply tube expansion pressure, and the outer tube and the inner tube are tightly connected. For example, Japanese Patent Application No. Sho 56-14380 (Japanese Unexamined Patent Publication No. Sho 57-130790) is well known.

The well-known conventional double pipe manufacturing apparatus using hydraulic pressure pipe expansion will be briefly explained based on FIG. 1.
A stainless steel inner tube 2 with a longer set length than the outer tube 1
are layered relative to each other to form a flared shape 3 at both ends, one end of which serves as a movable seal fitted to a fixed ram 5 fixed to a base 4 (left side in Figure 1) so as to be able to slide back and forth. is brought into contact with the conical tapered surface 7 at the tip of the movable seal head 6, and is divided into a plurality of parts on the outside of the conical tapered surface 7 and set;
A seal jaw 8 as a resettable clamp seal is clamped and fixed with a bolt 9,
Further, the other end of the inner tube 2 (on the right side in FIG. 1) is brought into contact with 3 portions of its flared shape against the conical tapered surface 7 at the tip of a fixed seal head 10 which is also fixed to the base 4 and serves as a fixed seal. A set and resettable seal jaw 8 which is divided into a plurality of parts on the outside of the conical tapered surface 7 is clamped and fixed in a fluid-tight manner with bolts 9, and an enlarged pipe flow communicating with the inner pipe 2 formed in the movable seal head 6 is formed. The valve 13 of the drainage passage 12 connected to the passage 11 is closed, while the valve 13 of the passage 14 of the expansion passage 11 communicating with the inner pipe 2 formed in the fixed seal head 10 is opened to supply the expansion liquid. The inner tube 2 is hydraulically expanded to abut against the outer tube 1, and both tubes are further expanded and plastically deformed as one,
Thereafter, the valve 13 is closed to stop the supply of the tube expansion liquid, and the valve 13 of the fixed seal head 6 is opened to drain the tube expansion liquid to obtain a double pipe.

In the process of hydraulic pipe expansion, the inner pipe 2 increases in diameter in the radial direction, but in the process, the inner pipe 2
contracts in the axial direction, and this contraction is absorbed by the movable sealing head 6 as it slides relative to the fixed ram 5.

Incidentally, although the amount of axial contraction of the inner tube 2 is theoretically calculated in advance and the gap l is set between the sealing jaw 8 of the movable seal head 6 and the end of the outer tube 1 through experiments, etc., in the hydraulic tube expansion process, , or if the cap l at the final stage is even slightly large, seal head pressure is applied to that part,
There is a risk that the inner tube 2 in that part will bulge outward and rupture.On the other hand, if the gap l is too short, the seals 8, 8 will be attached to both ends of the outer tube 1 in the middle of the hydraulic expansion tube. A directional pressure is applied, and as a result, buckling deformation occurs in the outer tube 1, especially at both ends thereof, and there is a problem that a double tube as designed cannot be obtained.

Of course, it is only necessary to set the gap l accurately, but there is a drawback that it is almost impossible in reality.

The amount of contraction of the inner tube 2 differs slightly depending on its material, and also varies slightly depending on the frictional resistance of the movable seal head 6 and the applied acceleration of the tube expansion liquid pressure. This is because, in reality, the designed gap l cannot be obtained.

Furthermore, as shown in the figure, the interior of the inner tube 2 is hollow during the hydraulic tube expansion process, so the tube expansion liquid applied must fill the entire hollow volume ^. When applying a high-pressure tube expansion liquid that produces a water compressibility of 5%, an extremely large amount of tube expansion liquid must be supplied, and a corresponding high pressure generator must be attached, which is an inconvenience. This also had the disadvantage of extremely high running costs.

<Date of invention> The purpose of the present invention is to solve the problem of gap setting in a double pipe manufacturing device having a movable seal based on the above-mentioned prior art, and to solve the problem of gap setting in a double pipe manufacturing device having a movable seal based on the above-mentioned prior art. To provide an excellent double pipe manufacturing device that uses the minimum necessary amount of liquid, is easy to expand, and can produce high-precision double pipes, thereby benefiting piping applications in various industries. It is.

<Structure of the Invention> In order to solve the above-mentioned problems, the structure of the present invention, which is in accordance with the above-mentioned object and whose gist is the scope of the above-mentioned claims, is to provide a relatively overlapping structure between an inner tube, which has been given a flared shape at both ends in advance, and an outer tube. and insert it outside the fixed core metal through the tube expansion chamber with a set minute gap, and bring it into contact with the conical tapered surface of the fixed seal at one end of the core metal, and actuate the actuator provided on the core metal. the clamp seal corresponding to the fixed seal is actuated, and the flared portion of the inner tube is sealed and fixed in a fluid-tight manner by the conical tapered surface of the fixed seal and the conical tapered surface of the clamp seal. The other flared portion of the inner tube is brought into contact with the conical tapered surface of a movable seal that is slidably axially mounted on the outer circumferential surface of gold, and is fixed by sealing the inner tube in a liquid-tight manner with a corresponding clamp seal. Then, a tube expansion liquid is supplied through the tube expansion flow path provided inside the core metal, and a tube expansion liquid pressure is applied in the tube expansion chamber on the outer surface of the core metal to exert a hydraulic pressure tube expansion action on the inner tube. In the hydraulic pipe expansion process, the inner pipe increases in diameter in the radial direction, becomes integrated with the outer pipe, and undergoes plastic deformation.
Furthermore, although the inner tube contracts in the axial direction, the amount of contraction is absorbed by the axial sliding of the movable seal against the core metal, and the length of the outer tube to be inserted is longer than that of the set inner tube. By making the length sufficiently longer than the set length of the inner tube, the gap is unnecessary and a bulge of the inner tube with respect to the outer tube does not occur, thus preventing rupture of the inner tube or buckling of the outer tube. Technical measures have been taken to ensure that the two integrated tubes shrink after the tube expansion liquid has been discharged without causing any problems, resulting in a highly accurate double tube.

<Embodiment - Configuration> Next, an embodiment of the present invention will be described below based on the drawings from FIG. 2 onwards. Furthermore, the first
Components having the same features as those in the drawings will be described using the same reference numerals.

In the embodiment shown in FIG. 2, reference numeral 15 denotes a double pipe manufacturing device which constitutes the gist of the present invention, and a cantilever type core bar 17 having a circular cross section and a predetermined diameter is fixed to a stand 16 fixed to the base 4. A hydraulic cylinder 18 as an actuator is formed in the front part of the hydraulic cylinder 18, and a piston rod 19 thereof is formed.
Seal 8' of the disk holder serving as a clamp seal is releasably fixed to the holder.
It is provided opposite to a conical tapered surface 7', which serves as a fixed seal, formed on the tip edge of the core metal 17.

Further, a seal head 6 as a movable seal is provided near the base of the core metal 17 so as to be slidable in the axial direction in a fluid-tight manner with respect to the core metal 17 via appropriate seals 20. A seal jaw 8 as a clamp seal divided into a plurality of parts in the circumferential direction of the tapered surface 7 is provided between the seal head 6 and the seal head 6 and connected to the seal head 6 via a tie rod 9.

Further, an enlarged flow passage 11 is formed in the seal head 6 and communicates with a drainage passage 12 having a valve 13.

Inside the core metal 17, an expansion flow passage 11' having a liquid supply port 22 is inserted into the expansion chamber 21 formed on the outer surface of the core bar 17, and a liquid supply passage 14 having a valve 13 is connected to the expansion passage 11'. It is connected.

Further, inside the core metal 17, there are operating oil passages 23, 23' connected to the hydraulic cylinder 18 at the tip thereof.
are likewise cut through and connected to the external passages 24, 24'.

Reference numeral 2 denotes an inner tube made of stainless steel, the inner end of which is formed into a flared shape 3 with a conical tapered surface opening outward, and is connected to the conical tapered surface 7 at the tip of the seal head 6 and the corresponding seal jaw 8. The conical tapered surface of the core bar 17 is configured to clamp and fix the core bar 17 in a fluid-tight manner. The tapered seal head 7' and the corresponding seal jaw 8' are similarly fixedly clamped in a liquid-tight manner.

Further, reference numeral 1 denotes an outer tube made of carbon steel, which is freely stacked on the outside of the inner tube 2.

Incidentally, 25 is a nut which is fixed to and released from the rod of the seal jaw 8' and the hydraulic cylinder 18.

<Embodiment - Effect> In the above-described configuration, a flare shape 3 having an outwardly opening conical tapered surface is formed at the inner end of the inner tube 2,
On the other hand, a flare shape 3' having a conical tapered surface facing inward is also formed on the outer end side.

Thus, the piston rod 19 of the hydraulic cylinder 18 provided at the tip of the core metal 17 of the double pipe manufacturing device 15
The nut 25 is disengaged to remove the seal 8' of the disk, and then the inner tube 2 with the flared shapes 3 and 3' is loosely installed on the outside of the core bar 17, and the inner end of the inner tube 2 has a flared shape. The third part is brought into contact with the conical tapered surface 7 of the seal head 6, and the opposing seal jaws 8, which have been divided in advance, are tightly fastened by tie rods 9 to seal and fix them in a fluid-tight manner.

In addition, the seal jaw 8' is brought into contact with the flare shape 3' of the conical tapered surface at the tip, and the nut 2 is tightened.
By tightly fastening 5, the flared portion at the tip of the inner tube 2 is sealed in a fluid-tight manner by the conical tapered surface of the seal head and the seal 8' of the disk, and the outer passage 24,
Pressure oil is supplied to and discharged from the hydraulic cylinder 18 via the hydraulic cylinder 24', and the flared portion 3' is sealed and fixed by the hydraulic cylinder 18 between the tapered surface 7' and the seal jaw 8'.

Thus, a small tube expansion chamber 21 having a ring-shaped cross section is formed between the inner tube 2 and the core metal 17.

Therefore, an outer tube 1 made of carbon steel is loosely inserted from the outside of the flared shape 3' of the inner tube 2, and its inner end is brought into contact with the seal jacket 8.

In this state, the outer end of the outer tube 1 is located directly above the flared tip portion of the inner tube 2 and becomes a free end.

Therefore, when the valve 13 of the drain passage 12 is closed and the valve 13 is opened from the liquid supply passage 14 to supply a predetermined pressurized tube expansion liquid, the tube expansion liquid is supplied to the tube expansion chamber 21 through the tube expansion flow passage 11', and The inner tube 2 is expanded and the diameter increases, and the inner tube 2 is integrated with the outer tube 1 to further increase its diameter and plastically deform. During this time, the axial contraction of the inner tube 2 is absorbed by the sliding of the seal head 6 against the core bar 17. .

When the plastic deformation of the inner and outer tubes 1 and 2 is completed, the tube expansion liquid is supplied to the valve 1 of the external passage 14.
3 and stop, open the valve 13 of the expansion passage 11 on the side of the seal head 6 to reduce the pressure of the expansion liquid in the expansion chamber 21 and drain it, and allow the pressure oil to flow back through the external passages 24, 24'. Then, the hydraulic cylinder 18 is moved to the right in the figure to loosen the nut 25, the sealing jacket 8' of the disc housing is removed, and the formed double pipe is removed from the core bar 17.

In the above process, the tip of the outer tube 1 is a free end, and due to the axial contraction of the inner tube 2, the inner tube 2
Since it overlaps with the inner tube, it does not buckle, and the end of the inner tube 2 does not bulge and rupture due to this.

By the way, this embodiment is suitable for manufacturing a double-walled pipe with a predetermined diameter or more, but when manufacturing a small-diameter double-walled pipe, the hydraulic cylinder 18 as an actuator at the tip of the core metal 17 may be Core metal 1
7. It may be difficult to provide it at the tip due to design considerations.

As shown in FIG. 3, the double tube manufacturing apparatus 15' in such a case has a disk seal 8' similar to the embodiment described above on the tip side of the core bar 17'.
A hydraulic cylinder 18' as an actuator is disposed at the proximal end of the core bar 17', and a hydraulic cylinder 18' as an actuator is disposed at the proximal end of the core bar 17'.
The hydraulic cylinder 1
The oil passages 24, 24' are connected directly to the outside of the tube 8', and the tube expansion liquid is supplied to the tube expansion chamber 21 between the inner tube 2 installed outside the core bar 17' through the supply liquid passage 14 on the stand side. On the other hand, expanded pipe flow passages 11, 11'' are provided on the core metal 17' side, and the rod 24 is
A tube expansion flow passage 11 is provided up to the front of the tube expansion passage 11 so as to communicate with each other, and a ring-shaped tube expansion flow passage 26' is provided in the core bar 17' at the tip of the tube expansion flow passage 11 to allow the supply of the tube expansion chamber 21. A mode of connection to port 26 is shown.

In the above-described embodiment, it is easy to operate the sealing mechanism 8' of the disc mechanism of the core metal 17' to form a small-diameter double tube, and the other inner tube 2
The effects of the sliding of the seal head 6, prevention of expansion and rupture, prevention of buckling of the outer tube 1, etc. due to the diameter increase and contraction in the axial direction are the same as in the above embodiment.

By the way, in the embodiment shown in FIG. 2, the core bar 17 has the same diameter over its entire length from its base to its tip, and therefore, the reaction force of the tube expansion pressure is applied to the seal head 6 in a direction to the left in the diagram. It turns out.

Therefore, as the diameter of the inner tube 2 increases, a contraction force in the axial direction acts, but in the balance between the contraction force and its reaction force against the seal head 6, if the contraction force is large, it is certain that a double-walled tube cannot be manufactured. However, if this is not the case, the reaction force against the seal head 6 must be eliminated or reduced.

However, in the embodiment shown in FIG. 3, since the stepped portion 27 is formed at the sliding portion of the seal head 6 relative to the core bar 17', no reaction force is generated against the seal head 6, and
Therefore, the embodiment shown in FIG. 3 has the advantage that the double tube can be manufactured easily because the contraction force of the inner tube 2 can be easily obtained.

However, in the embodiment shown in FIG. 3, the diameter of the stepped portion 27 is made larger than that of the tube expansion chamber 21 at the front thereof, so that the axial contraction force on the inner tube 2 is made more aggressive. It also has the advantage of being able to be made larger.

As shown in FIG. 4, such technical means include forming an external cylinder 28 on the outside of the base of the core bar 17, and sliding the seal head 6'' in the axial direction with respect to the external cylinder 28 through the seal 20. The outer cylinder 28 and the tube expansion chamber 21 are made to communicate with each other via the tube expansion flow passage 11 inside the seal head, and the inner diameter of the outer cylinder 28 is equal to the inner diameter of the inner tube 2, and By increasing the size, such an axial reaction force can be eliminated and an axial contraction force can be positively applied to the inner tube 2.

It is needless to say that the embodiments of the present invention are not limited to the above-mentioned embodiments, and the actuator for the seal of the disk at the tip of the core metal is not limited to a hydraulic cylinder, but may be driven by a motor.
Further, various embodiments can be adopted, such as a collect-chuck type or a one-touch type.

Furthermore, the relative overlapping of the outer tube with respect to the inner tube may be such that the outer tube is sheathed after the inner tube is set on the core bar.
Further, the outer tube and the inner tube may be layered relatively to each other, and both of the set may be covered with a metal core, and the application thereof can be made according to the design mode as appropriate.

<Effects of the Invention> According to the present invention, basically, when manufacturing a double pipe such as a corrosion-resistant double pipe for oil country tubular goods, both ends of the inner pipe are sealed liquid-tight and a pipe expansion liquid is supplied. When pipe expansion pressure is applied to plastically deform the two, the axial contraction of the inner pipe that inevitably occurs as the diameter of the inner pipe increases is freely allowed, and the free end is transformed into a guaranteed outer pipe. On the other hand, since the tube is expanded by pressure welding, the length of the outer tube can be set to a sufficient length without having to accurately account for the contraction of the inner tube in the axial direction. This prevents bulging and rupture caused by the breakage, and also avoids buckling deformation at the end of the outer tube, resulting in an excellent effect of obtaining a double tube with high precision.

In addition, a fixed seal is formed at the tip of the core bar that is loosely placed inside the inner tube, and an expansion passage is formed inside the core bar, so that the core bar functions as a kind of support. Not only does it function as a fixed sealing means for one end of the inner tube, but it also has the excellent effect of functioning as a tube expansion flow path.

Furthermore, since the tube expansion chamber is located inside the inner tube, the volume of the tube expansion chamber between the core metal and the inner tube is reduced, and as a result, the amount of high-pressure tube expansion liquid supplied is reduced due to the compression of the tube expansion liquid supplied. Therefore, the high-pressure tube expansion liquid supply device does not need to be large-sized, the power required for it is small, and running costs can be reduced.

Furthermore, since there is no need for a clamp seal on the outer tube, there is also the advantage that the device is simpler.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a double pipe manufacturing apparatus based on the prior art, Fig. 2 and the following are explanatory views of embodiments of the present invention;
The figure is a sectional view of another embodiment, and FIG. 4 is a sectional view of another embodiment. 7'...Fixed seal, 8'...Clamp seal,
6,6''...Movable seal, 3'...Clamp seal, 11'',11...Pipe expansion flow passage, 17,1
7'... Core metal, 18, 18'... Actuator,
21... Expansion chamber.

Claims (1)

[Claims] 1. The outer tube is provided with a fixed seal for one end of the inner tube which can be stacked relative to each other, and a clamp seal is provided opposite to the fixed seal, while the movable seal for the other end of the inner tube is also provided with a clamp seal. In a double pipe manufacturing device in which either the fixed seal or the movable seal is provided with an expanded flow passage, the fixed seal is formed at the tip of the core metal loosely installed in the inner pipe, and the fixed seal is formed at the tip of the core metal loosely installed in the inner pipe. A clamp seal actuator is attached to the mandrel, and the movable seal is provided that can freely slide in the axial direction with respect to the mandrel, and the mandrel has a tube expansion flow passage communicating with the tube expansion chamber on the side thereof. A double pipe manufacturing device characterized in that: