JP2017075746A - Winding type pressure vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a winding type pressure vessel capable of easily detecting a defect at an early stage even if the defect such as a crack occurs in a welded joint portion while a reliable complete penetration welding method can be employed for welding connection of tube split pieces.SOLUTION: A pressure vessel body 1 that constituting a winding type pressure vessel 100 according to one embodiment of the invention and that includes: an inner tube 7 formed by weld connection of a plurality of inner tube split pieces 9; and a burner cylinder 8 having a groove 10a on an inner surface externally fitted to the inner tube 7. In a cross section in a circular cylinder axial vertical direction, a welding position 22 of inner tube split pieces 9 and the position of the groove 10a are made to coincide.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a large pressure vessel used in an isotropic pressure pressurizing apparatus that pressurizes an object to be processed with a gas or liquid pressure medium.

  Conventionally, this type of pressure vessel is, for example, described in Patent Document 1 below. The prior art is configured as follows. A plurality of cylinder segments are welded and joined to form a cylindrical cylinder body, and a steel band is wound around the outer peripheral surface to apply a precompression force (prestress) to the cylinder body. Here, Patent Document 1 describes that at the stage where a plurality of cylinder segments are welded together, a gap is formed between the cylinder segments, and then the steel band is wound to reduce the gap. (Eventually disappear almost or completely) Thereby, the precompression force (prestress) of the welded joint is increased. If the precompression force (prestress) of the welded joint is increased, it is possible to prevent the occurrence of defects such as cracks in the welded joint between the segments, which are structurally weak parts.

  Patent Document 1 discloses that the pressure in the cylinder body is reduced by letting the pressure medium in the cylinder body escape from a recess (cavity) provided at the joint of the cylinder segment, thereby suppressing the growth of cracks generated at the joint. The contents to be described are described.

Japanese Patent No. 5694564

  First, a method in which a gap is formed between cylinder segments described in Patent Document 1 and then the pre-compression force (prestress) of the welded joint is increased by reducing the gap is determined between cylinder segments. It has the disadvantage that the welded joint area must be reduced. If the weld joint area is reduced, the reliability of welding is impaired. The most reliable welding is a so-called full penetration weld in which a weld bead enters the entire connection area without any gap. In addition, in the gap portion between the cylinder segments, even if this gap disappears almost completely, the leakage of the pressure medium cannot be prevented. Therefore, leakage of the pressure medium is prevented only with a welded joint having a small area. When the above-described full penetration weld is adopted, the weld joint area becomes large, and leakage of the pressure medium can be prevented at the weld joint having a large area.

  Further, in Patent Document 1, an attempt is made to suppress the growth of a crack generated at the seam by providing a recess (cavity) at the joint of the cylinder segment. The joint (joint part) between the segments, which are weak parts, is structurally weakened.

  In addition, when using a welding connection in a pressure vessel, a periodic inspection for ensuring safety is essential. In the case of wire-wound pressure vessels, it is possible to inspect the welded joint from the inside of the pressure vessel body, but due to the presence of the wire wound around the outer periphery of the pressure vessel body, the welded joint from the outside of the pressure vessel body Inspection of the department is difficult. As a second best measure, it is desirable to detect an abnormality (occurrence of a defect such as a crack) in the welded joint as early as possible before the fatal fracture of the welded joint.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cylindrical pressure vessel body in which a plurality of divided pieces in a divided form are welded and joined. Full penetration welding, which is a highly reliable welding method, can be used for welded joints between split pieces, and even if a defect such as a crack occurs in the welded joint, it can be easily done at an early stage It is an object of the present invention to provide a wire-wound pressure vessel having a structure that can be detected.

  A wire-wound pressure vessel according to the present invention comprises a cylindrical pressure vessel body and a wire-wound type provided with a wire material that applies a precompression force to the pressure vessel body in a state of being wound around the outer periphery of the pressure vessel body. It is a pressure vessel. The pressure vessel main body includes an inner cylinder formed by welding and joining a plurality of divided inner cylinder pieces, and an outer cylinder having a groove on an inner surface that is externally inserted into the inner cylinder. In the cross section in the direction perpendicular to the cylinder axis, the welding position between the inner cylinder divided pieces and the position of the groove are matched.

  According to this configuration, when a defect such as a crack occurs in the welded joint portion between the inner cylinder divided pieces and penetrates the welded joint in the radial direction even a little, the pressure medium leaks from the inside of the pressure vessel body, and the outer cylinder It flows through a groove formed on the inner surface of. Detection of the pressure medium flowing through this groove is easy. Therefore, even if a defect such as a crack occurs in the welded joint portion between the inner cylinder divided pieces, it can be easily detected at an early stage. Moreover, according to the said structure, complete penetration welding which is a reliable welding method can be employ | adopted for the welding joining of inner cylinder division | segmentation pieces.

  Further, in the present invention, the inner cylinder divided piece is an arc-shaped divided piece having a shape in which the inner cylinder is divided in the circumferential direction, and in the cross section in the direction perpendicular to the cylindrical axis, It is preferable that the position of the groove coincides in the circumferential direction.

  A tensile stress in the circumferential direction is generated by the pressure medium introduced into the pressure vessel main body at the above-described welded joint portion between the inner cylinder divided pieces. Therefore, this welded part is a particularly weak (strong in strength) part of the inner cylinder, that is, a part where defects such as cracks are likely to occur. By making it possible to detect the pressure medium by aligning the position of the groove with this portion, the safety of the pressure vessel is further increased.

  Further, in the present invention, the outer cylinder is formed by welding a plurality of outer cylinder division pieces having a circular arc shape in the form of division in the circumferential direction, and the inner cylinder division in the cross section in the direction perpendicular to the cylinder axis. It is preferable that the welding position between the pieces and the welding position between the outer cylinder split pieces are shifted in the circumferential direction.

  According to this configuration, when a defect such as a crack occurs in the welded joint portion between the inner cylinder divided pieces and the pressure medium leaks therefrom, the pressure medium reaches the welded joint portion between the outer cylinder divided pieces. (The pressure medium flows basically through the groove formed on the inner surface of the outer cylinder, and therefore basically does not reach the groove). This contributes to suppressing the occurrence of defects at the welded joint between the outer cylinder split pieces.

  Furthermore, in the present invention, it is preferable that the pressure medium detecting means is connected to the groove. According to this configuration, it is possible to easily detect the pressure medium flowing in the groove formed on the inner surface of the outer cylinder.

  According to the wire-wound pressure vessel according to the present invention, it is possible to employ complete penetration welding, which is a reliable welding method, for welding and joining the cylindrical divided pieces, and it is assumed that the weld joint is cracked. Even if a defect occurs, it can be easily detected at an early stage.

It is a longitudinal cross-sectional view (BB sectional drawing of FIG. 2) of the wire wound type pressure vessel which concerns on one Embodiment of this invention. It is AA sectional drawing of FIG. It is a perspective view of an inner cylinder division piece. It is a perspective view of an outer cylinder division piece.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The wire-wound pressure vessel described below is a pressure vessel suitable for use in a hot isostatic pressurizing device, but the wire-wound pressure vessel according to the present invention has a cold isotropic pressure. It can also be used as a pressure vessel used in a pressurizing device. Further, a pressure medium that is placed in a wire-wound pressure vessel together with an object to be processed and pressurizes the object to be processed is a gas such as argon or a liquid such as water. Examples of the object to be processed include metal powder, ceramic powder, resin powder, food, and the like.

(Configuration of wire wound pressure vessel)
Based on FIGS. 1-3, the structure of the wire wound type pressure vessel 100 which concerns on one Embodiment of this invention is demonstrated. The wire-wound pressure vessel 100 is formed by winding a cylindrical pressure vessel body 1 into which an object to be processed and a gas as a pressure medium are placed, and a wire rod provided with tension around the outer periphery of the pressure vessel body 1. Layer 2. The lower end opening of the pressure vessel body 1 is closed by the lower lid 4, and the upper end opening is closed by the upper lid 3. An upper header 5 is disposed at the upper end of the pressure vessel body 1, and a lower header 6 is disposed at the lower end.

  The pressure vessel main body 1 described above includes an inner cylinder 7 formed by welding a plurality of inner cylinder divided pieces 9 having a cross-sectional arc shape divided in the circumferential direction, and a cross-section arc-shaped shape divided in the circumferential direction. The outer cylinder 8 is formed by welding a plurality of outer cylinder divided pieces 10 together. The outer cylinder 8 is extrapolated to the inner cylinder 7.

  The inner cylinder divided piece 9 is a plate of a metal (for example, carbon steel) that has an arc shape in a plan view and a rectangular shape in a side view (for example, carbon steel), and a plurality of inner cylinder divided pieces 9 are combined in a circumferential shape. A cylindrical inner cylinder 7 is formed by bonding. Similarly, the outer cylinder divided piece 10 is a metal plate (for example, carbon steel) that has an arc shape in a plan view and a rectangular shape in a side view, and a plurality of outer cylinder divided pieces 10 are combined in a circumferential shape to completely melt the mating surfaces. A cylindrical outer cylinder 8 is formed by joint welding. In addition, illustration of a weld bead is abbreviate | omitted.

  The inner diameter of the outer cylinder 8 is a dimension that allows the outer cylinder 8 to be extrapolated to the inner cylinder 7, and specifically, is the same dimension as the outer diameter of the inner cylinder 7 or slightly larger. For the convenience of wire winding described later, the inner diameter of the outer cylinder 8 is slightly smaller than the outer diameter of the inner cylinder 7, and the outer cylinder 8 is extrapolated to the inner cylinder 7 by shrink fitting, It is preferable to insert the inner cylinder 7 into the outer cylinder 8 with a cold fit, and to integrate both cylinders before the wire winding operation.

  Here, when the outer cylinder 8 is fitted into the inner cylinder 7, a groove 10a formed on the inner surface of the outer cylinder 8 (outer cylinder divided piece 10) so as to extend in the cylindrical axis direction Da, and also extends in the cylindrical axis direction Da. The welding line between the inner cylinder division pieces 9 (the welding position 22 between the inner cylinder division pieces 9) is made to coincide. In other words, in the cross section in the direction perpendicular to the cylinder axis (FIG. 2), the welding position 22 between the inner cylinder divided pieces 9 and the position of the groove 10a formed on the inner surface of the outer cylinder 8 are made to coincide in the circumferential direction Dc. In the case of not performing shrink fitting or cold fitting, the outer cylinder 8 is formed on the inner surface of the outer cylinder 8 as described above prior to extrapolation of the outer cylinder 8 to the inner cylinder 7 and then performing wire winding work. The weld line between the groove 10a and the inner cylinder divided piece 9 (the welding position 22 between the inner cylinder divided pieces 9) is matched.

  It should be noted that the size of the groove 10a need not be as large as shown in FIG. As described above, since the inner cylinder 7 and the outer cylinder 8 are integrated, there is only a microscopic gap between the inner cylinder 7 and the outer cylinder 8. Therefore, it is good also as a groove | channel smaller than the groove | channel 10a shown by FIG.

  The above-described weld line between the inner cylinder divided pieces 9 (weld position 22 between the inner cylinder divided pieces 9) and the weld line between the outer cylinder divided pieces 10 extending in the cylindrical axial direction Da (weld position between the outer cylinder divided pieces 10). 23) is shifted without matching. That is, in the cross section in the direction perpendicular to the cylindrical axis (FIG. 2), the welding position 22 between the inner cylinder divided pieces 9 and the welding position 23 between the outer cylinder divided pieces 10 are shifted in the circumferential direction Dc.

  In the present embodiment, the semicircular groove 10a is used, but the shape of the groove 10a is not limited to this. However, it is preferable that the groove has a smooth curved surface as a whole so as not to concentrate stress.

  On the outer peripheral surface of the outer cylinder 8 in which the inner cylinder 7 is fitted, plate-like long spacers 11 are arranged at regular intervals in the circumferential direction Dc. The spacer may be rod-shaped.

  A tensioned piano wire (wire material, not shown) is wound around the outer periphery of the outer cylinder 8 constituting the pressure vessel main body 1 with a plurality of the spacers 11 interposed therebetween (wire winding operation). Thereby, the wire wound layer 2 is formed. The piano wire is, for example, a flat piano wire. The tension applied to the piano wire is determined in advance by calculation so that a predetermined compressive residual stress that is planned in design is generated in the inner cylinder 7 and the outer cylinder 8 at the end of the wire winding operation.

  After completion of the wire winding operation, sufficient compressive residual stress is generated in the inner cylinder 7 and the outer cylinder 8. Therefore, for example, even when the inner diameter of the outer cylinder 8 is larger than the outer diameter of the inner cylinder 7 as a dimension before the wire winding work, after the wire winding work is finished, the gap between the inner cylinder 7 and the outer cylinder 8 is increased. The gap disappears and both cylinders are integrated.

  Due to the presence of the plurality of spacers 11 described above, a cooling water channel 21 is formed between the outer cylinder 8 and the wire winding layer 2. The cooling water channel 21 is a space defined by the outer cylinder 8, the wire wound layer 2, and the spacer 11, and a plurality of cooling water channels 21 are formed along the cylindrical axial direction Da. Here, the upper header 5 is formed with a cooling water introduction water channel 5a and an annular header water channel 5b, and the lower header 6 is formed with a cooling water discharge water channel 6a and an annular water collecting channel 6b. Has been. The cooling water from the introduction water channel 5a formed in the upper header 5 flows through the header water channel 5b, the plurality of cooling water channels 21, and the collecting water channel 6b in this order, and then is discharged from the discharge water channel 6a.

  As will be described in detail later, the groove 10a formed in the inner surface of the outer cylinder 8 and extending in the cylindrical axial direction Da becomes a firm gas leak detection groove when the inner cylinder 7 and the outer cylinder 8 are integrated. . The groove 10a (gas leak detection groove) communicates with an annular gas collection groove 6c formed in the lower header 6. A gas leak detector 13 as a pressure medium detection means is connected to the gas leak detection pipe 12 and the gas collection pipe. It is connected to the groove 10a through the gas groove 6c.

(Structure weak part of pressure vessel)
When the pressure in the pressure vessel main body 1 is zero (normal pressure), compressive residual stress in the circumferential direction Dc is generated in the inner cylinder 7 and the outer cylinder 8 by the precompression force from the wire winding layer 2 (piano wire). However, when the pressure medium (gas) is introduced into the pressure vessel body 1, tensile stress in the circumferential direction Dc is generated in the inner cylinder 7 and the outer cylinder 8. As the pressure vessel body 1 is pressurized, the tensile stress increases and the compressive residual stress decreases. Eventually, the compressive residual stress is canceled by the tensile stress due to the gas pressure, and finally, the inner cylinder 7 and the outer cylinder 8 are in a state where the tensile stress is applied. When the pressure medium (gas) is extracted from the pressure vessel main body 1, the inner cylinder 7 and the outer cylinder 8 return to the state in which the compressive residual stress is applied. Thus, compressive stress and tensile stress act alternately on the inner cylinder 7 and the outer cylinder 8 by the introduction and discharge of the pressure medium (gas).

  In this case, as apparent from the material mechanics, the stress amplitude increases toward the inner side of the cylinder. Therefore, when the inner cylinder 7 and the outer cylinder 8 are compared, the inner cylinder 7 has a greater stress amplitude than the outer cylinder 8. The wire wound layer 2 is originally under a large tensile stress, and the stress is amplified under the tensile stress during the introduction and discharge of the pressure medium (gas) into the pressure vessel main body 1, but the magnitude of the stress amplitude is as follows. It is smaller than the inner cylinder 7 and the outer cylinder 8. Moreover, the strength of the piano wire is much higher than that of a general carbon steel that is a material of both cylinders. Further, the inner cylinder 7 is in direct contact with a high pressure medium. From these, the most critical member from the viewpoint of the safety of the pressure vessel is the inner cylinder 7, and the welded joint (the welded joint between the inner cylinder divided pieces 9) in each part of the inner cylinder 7 is the weakest part. is there.

(When a crack occurs at the joint of the inner cylinder (welded joint between the inner cylinder split pieces 9))
In the wire-wound pressure vessel 100, a gap is not formed between the segments as in the structure of the pressure vessel described in Patent Document 1, and therefore, the welded joint of each of the divided pieces 9 and 10 is highly reliable. Full penetration welding, which is a welding method, can be employed.

  Even if a crack occurs in the welded joint portion between the inner cylinder split pieces 9 constituting the inner cylinder 7 and the crack grows due to a fatigue phenomenon and penetrates the inner cylinder 7 in the radial direction, the inner cylinder 7 The outer cylinder 8 having a small stress amplitude acting also is easily kept healthy. Therefore, even if a gas leak occurs between the inner cylinder 7 and the outer cylinder 8, the pressure vessel main body 1 can maintain its shape as a cylindrical cylinder. That is, by making the pressure vessel body 1 into two layers (a plurality of layers), the probability that a fatal defect occurs simultaneously in the two layers (a plurality of layers) is reduced.

  Further, since the groove 10a is provided on the inner surface of the outer cylinder 8 along the weld line between the inner cylinder divided pieces 9, gas (pressure medium) leaking from the welded joint portion of the inner cylinder 7 passes through the groove 10a. Through this, the gas leak detector 13 is reached, whereby the occurrence of a crack at the welded joint portion of the inner cylinder 7 can be easily detected at an early stage.

  Further, considering the securing of the strength of the inner cylinder 7, the groove 10 a has a sufficiently large space sectional area as compared with the microscopic gap between the integrated inner cylinder 7 and the outer cylinder 8. Can be. For this reason, the gas leaking from the welded joint portion of the inner cylinder 7 hardly enters the gap between the inner cylinder 7 and the outer cylinder 8, and most of the gas flows through the groove 10a. Therefore, a small amount of gas leakage at a stage where the crack is small can be detected by the gas leakage detector 13.

(Other functions / effects)
Further, when the cooling water passage 21 is provided between the outer cylinder 8 and the wire wound layer 2, the wire wound pressure vessel 100 is used for the purpose of keeping the inside at a high temperature like hot isostatic pressing. However, the temperature of the pressure vessel body 1 can be kept in a safe temperature range by flowing the cooling water through the cooling water passage 21.

  In addition, since the pressure vessel main body 1 has two layers (a plurality of layers), the inner cylinder 7 that is the most critical member from the viewpoint of safety of the pressure vessel has a structure that does not come into contact with the cooling water. Therefore, the inner cylinder 7 is not rusted or corroded by the cooling water.

(Modification)
In the above-described embodiment, the spacer 11 is disposed between the outer cylinder 8 and the wire winding layer 2 to provide the cooling water channel 21, but a wire rod (for example, on the outer peripheral surface of the outer cylinder 8 without the spacer 11 being disposed). The wire winding layer 2 may be formed by directly winding a piano wire. In the case of cold isostatic pressurization, the temperature in the pressure vessel main body 1 is normal temperature, and in this case, the cooling water passage 21 (cooling water) is unnecessary.

  In the above-described embodiment, the inner cylinder divided piece 9 having a circular arc shape in a plan view and a rectangular shape in a side view has a weld line between adjacent inner cylinder divided pieces 9 and an outer cylinder 8 aligned with the weld line. The groove 10a formed on the inner surface of the cylinder extends in the cylindrical axial direction Da. Instead of this structure, for example, an inner cylinder divided piece having a circular arc shape in a plan view and a parallelogram in a side view may be used (the same applies to the outer cylinder divided piece 10). In this case, the weld line between the adjacent inner cylinder divided pieces and the groove formed on the inner surface of the outer cylinder 8 aligned with this will extend obliquely with respect to the cylindrical axis direction Da.

  In the above-described embodiment, the inner cylinder 7 and the outer cylinder 8 are each divided in the circumferential direction Dc. However, both the cylinders 7 and 8 are divided in the cylindrical axis direction Da, and the divided members are used. You may weld-join each other by complete penetration welding. In this case, the tubular segment is an annular segment.

  In this case, with respect to the inner inner cylinder 7, the cylinder shaft so that gas (pressure medium) leakage from the circular seam extending in the direction perpendicular to the cylinder axis (direction perpendicular to the cylinder axis direction Da) can be detected. In the cross section in the vertical direction, a groove is provided on the inner surface of the outer cylinder 8 so as to coincide with the position of the seam (weld joint) extending in the vertical direction of the cylinder axis.

  Thus, the inner cylinder divided piece constituting the inner cylinder 7 may be a divided piece having a circular arc shape in which the inner cylinder 7 is divided in the circumferential direction Dc, or is divided in the cylindrical axial direction Da. It may be a split piece in the form of a ring (the same applies to the outer cylinder 8).

  In addition, it is needless to say that various modifications can be made within a range that can be assumed by those skilled in the art.

1: Pressure vessel body 2: Wire winding layer 3: Upper lid 4: Lower lid 5: Upper header 6: Lower header 7: Inner cylinder 8: Outer cylinder 9: Inner cylinder divided piece 10: Outer cylinder divided piece 10a: Groove 11: Spacer 12: Gas leak detection pipe 13: Gas leak detector (pressure medium detection means)
21: Cooling water channel 22, 23: Welding position 100: Wire-wound pressure vessel

Claims (4)

A cylindrical pressure vessel body;
A wire rod that imparts a precompression force to the pressure vessel body in a state wound around the outer periphery of the pressure vessel body;
A wire wound pressure vessel comprising:
The pressure vessel body is
An inner cylinder formed by welding and joining a plurality of divided pieces of the inner cylinder;
An outer cylinder externally inserted into the inner cylinder and having a groove on the inner surface;
Have
A wire-wound pressure vessel characterized in that, in a cross section in a direction perpendicular to the cylinder axis, a welding position between the inner cylinder divided pieces and a position of the groove coincide with each other. The wire wound pressure vessel according to claim 1,
The inner cylinder divided piece is a divided piece having a circular arc cross section in a form in which the inner cylinder is divided in the circumferential direction,
A wire wound pressure vessel characterized in that, in a cross section in a direction perpendicular to the cylinder axis, a welding position between the inner cylinder divided pieces and a position of the groove coincide with each other in the circumferential direction. The wire wound pressure vessel according to claim 2,
The outer cylinder is formed by welding and joining a plurality of outer cylinder divided pieces having a cross-sectional arc shape divided in the circumferential direction,
A wire wound pressure vessel characterized in that a welding position between the inner cylinder divided pieces and a welding position between the outer cylinder divided pieces are shifted in the circumferential direction in a cross section in a direction perpendicular to the cylindrical axis. In the wire wound pressure vessel according to any one of claims 1 to 3,
A wire-wound pressure vessel, characterized in that a pressure medium detecting means is connected to the groove.

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