JP4400511B2 - Flange reinforcing jig and method of reinforcing flange joint - Google Patents

Description

  The present invention relates to a flange reinforcing jig for reinforcing the joining force of a flange in a flange joint portion of a pipe flange joint and a method for reinforcing the flange joint portion.

  Flange joints used when connecting pipes or devices such as valves are usually determined in terms of flange shape, number of bolts, material, etc. based on the design pressure of the pipes. Such a flange joint is designed to ensure sufficient strength against internal pressure that is always applied, and to exert sufficient surface pressure on the flange joint surface so that leakage does not occur.

  However, when a flange joint is actually used, it is not uncommon for an external force such as an axial force or bending to act in addition to the internal pressure. Even in the case of a flange having a sufficient strength against the internal pressure, there are many cases in which leakage occurs in an environment in which an external force acts, causing a problem.

  In an operating environment in which an external force is assumed to act in advance, it is possible to design or select a flange that can withstand the external force. However, if the existing flange joint that has already been installed and used is found to have an external force or if it is necessary to change the assumed external force, measures are taken against the external force. Is required.

  Removing the problematic flange joint from the pipe and replacing it with a stronger one is a drastic measure, but in this case the process and operation of the pipe must be stopped and the fluid in the pipe removed. Depending on the operating environment, the work itself can be significant, which can lead to a significant loss of opportunity. In order to avoid such a risk, the flange joint should be replaced in accordance with the scheduled shutdown period such as periodic inspection. However, if there is still a period before the regular inspection, you must accept the risk of leaving the problematic flange in the meantime. Therefore, it is necessary to reinforce the flange joint as easily and inexpensively as possible as a permanent measure, at least until the scheduled operation stop time such as periodic inspection, for the flange joint that needs to be replaced.

  Here, the airtightness in the flange joint is achieved by maintaining the surface pressure at which the flange presses the gasket and packing between the flanges at a certain level or higher. Therefore, in order to prevent leakage against the external force of tension and bending acting on the flange joint, it is necessary to ensure the surface pressure level even when the external force is applied. When an external force in the direction in which the flange joint surface opens is applied, the surface pressure of the flange decreases by the amount of the external force. In addition, since the bolt joint position of the flange is arranged outside the joint portion with the pipe where an external force acts on the flange, a bending moment is generated between the joint portion with the pipe and the bolt joint portion. The closer to the joint with the tube, the more the flange deforms in the direction in which the joint surface opens.

  For this reason, the reduction in the surface pressure of the flange becomes more prominent the closer to the joint with the pipe, and leakage occurs when the surface pressure cannot maintain the airtight level somewhere on the outer periphery of the airtight surface of the flange. Therefore, the application of force for keeping the flange hermetic and suppressing the deformation of the flange is more effective at a location closer to the joint with the pipe.

As a method and apparatus for taking measures against external force on an existing flange joint in a live pipe state, for example, “Flange joint security jig, pit valve safety” described in Japanese Patent Application Laid-Open No. 2004-316767 (Patent Document 1). There are jigs and security methods using these jigs ”. In this method, the rear surface of the flange is sandwiched between clamping members and tightened with a coupling member. In this method, a clamping member is applied to the base of the back surface of the flange, and the clamping member is tightened with a coupling member to add a joining force to the flange and to improve the security by resisting deformation due to external force. It is aimed. In this technique, the reinforcing jig is composed of two holding members and at least one coupling member. Accordingly, there are at least two connection portions for connecting the holding member and the coupling member.
JP 2004-316767 A

  However, in the method described in Patent Document 1, even when the holding member is installed in parallel to the rear surface of the flange when the reinforcing jig is attached, the two holding members are tightened with the coupling member after that. It leans into a square shape. This is influenced by the bending rigidity of the jig itself, but is rather greatly influenced by the gap between the connecting portions of the jigs and the state of the contact surface. For example, when a bolt is used as the coupling member, it is difficult to maintain the parallel arrangement state of the clamping members due to the existence of a gap between the bolt and the bolt hole and the fitting tolerance of the bolt structure itself. When the holding member is tilted, the portion that presses the flange root is also tilted, and the portion that applies force to the flange is separated from the joint with the tube, so that the reinforcing effect is reduced.

  Further, when the tilted members are connected to each other with bolts and nuts, the bolts and nuts are only partially in contact with the holding member, so that when an external force is applied, local deformation tends to occur at the contact portions. Such a deformation occurring in the connecting portion allows a large displacement at the flange base even if it is a small deformation, and works in a direction to reduce the reinforcing effect.

  Therefore, the present invention provides a flange reinforcing jig and a flange connecting portion reinforcing method capable of reliably improving the reinforcing effect of the flange joint by a simple jig and improving the airtight performance of the flange joint against an external force. The purpose is to provide.

The above problems are solved by the following invention.
[1] A flange reinforcing jig at a flange joint of a pipe flange joint,
In a state where the flange reinforcing jig is in contact with a plurality of reinforcing members arranged at intervals in the circumferential direction of the flange so as to straddle the flange joint portion and the root portion of the flange portion rear surface, An abutting member pressed against the tube and a fastening member for fixing the plurality of reinforcing members to the tubular body,
The reinforcing member is in contact with the pressing portion A1 that is in contact with the root portion on the back surface of one flange portion, and the front surface is in contact with the back surface of the abutting member that is in contact with the root portion on the back surface of the other flange portion. A pressing portion A2 that presses against the pressing portion, and a tightening portion A3 that protrudes along the tube wall on the pressing portion A2 side,
The flange reinforcing jig, wherein the tightening member has a ring shape, and is configured such that each of the tightening portions A3 of the plurality of reinforcing members can be tightened in the center direction of the pipe.
[2] A flange reinforcing jig at a flange joint of a pipe flange joint,
The flange reinforcing jig comprises a plurality of reinforcing members arranged at intervals in the circumferential direction of the flange so as to straddle the flange joint portion, and a fastening member for fixing the plurality of reinforcing members to the pipe body. ,
The reinforcing member extends along the tube wall on the side of the pressing portion B2 and the pressing portion A1 that contacts the root portion on the back surface of one flange portion, the pressing portion B2 that contacts the root portion on the back surface of the other flange portion. And a tightening portion A3 projecting from
The flange reinforcing jig, wherein the tightening member has a ring shape, and is configured such that each of the tightening portions A3 of the plurality of reinforcing members can be tightened in the center direction of the pipe.
[3] In the above [1] or [2], a ring-shaped auxiliary fastening member that fastens a plurality of reinforcing members arranged in the center direction of the pipe, and a portion that straddles each flange joint portion of the plurality of reinforcing members Flange reinforcement jig characterized by being arranged at the top of
[4] A method for reinforcing a flange joint, comprising reinforcing the flange joint using the flange reinforcing jig according to any one of [1] to [3].

  According to the present invention, there is provided a flange reinforcing jig and a flange connecting portion reinforcing method capable of reliably improving the reinforcing effect of the flange joint portion with a simple jig and improving the airtight performance of the flange joint portion against an external force. Provided.

  Hereinafter, an example of the best mode for carrying out the present invention will be described.

  The flange reinforcing jig in the flange joint portion of the pipe flange joint according to the present invention is in contact with a plurality of reinforcing members arranged at intervals in the circumferential direction of the flange so as to straddle the flange joint portion, and the root portion of the flange portion rear surface. In this state, the contact member is pressed against the rear surface of the flange portion by the reinforcing member, and a tightening member for fixing the plurality of reinforcing members to the tube.

  In FIG. 1, an example of schematic structure of the flange reinforcement jig | tool which concerns on this invention is shown. Here, FIG. 1 is a cross-sectional view seen from the circumferential direction of the flange joint, and shows an example of the arrangement of one reinforcing member 1, the abutting member 2, and the tightening member 3 constituting the flange reinforcing jig. It is a thing.

  The reinforcing member 1 has, for example, a columnar, thick plate or rod-like member bent into a gate shape so as to straddle the flange joint, and is formed at one end of the root of the back surface of one flange portion 4a. The pressing portion A1 bent so as to abut the portion, and the front surface abuts on the back surface of the abutting member 2 abutting on the root portion of the back surface of the other flange portion 4b, and the abutting member 2 is pressed against the back surface of the flange portion 4b. It has a pressing portion A2 and a tightening portion A3 that is formed at the other end portion on the pressing portion A2 side so as to protrude along the tube wall.

  The abutting member 2 only needs to be provided at least at a position where the reinforcing member 1 is disposed. However, the abutting member 2 may be provided on the entire circumference in the circumferential direction of the root portion on the rear surface of the flange 4b or on a part thereof.

  FIG. 2 shows an example of a preferred shape of the abutting member 2 when the abutting member 2 is provided on the entire circumference in the circumferential direction of the root portion on the back surface of the flange 4b or a part thereof. As shown in FIG. 2, the abutting member 2 is formed in an arc shape, and a notch portion that avoids existing bolts and nuts provided on the flange is provided, so that it can be accurately installed at the root portion on the back surface of the flange 4b. . Further, by providing the tube body side contact surface of the abutting member 2 with a curvature matched to the shape of the tube, even when the abutting member 2 has a certain length in the circumferential direction of the tube, the abutting member 2 is connected to the flange 4b. It can be installed in close contact with the root portion on the back.

  Here, the abutting member 2 shown in FIG. 2 shows a case where the angle formed by the arc is 90 °. However, if the angle is within a range that can be accurately attached to the root portion of the back surface of the flange 4b, the abutting member 2 forms the arc. The angle is not limited. When the angle formed by the arc is 90 °, the four abutting members 2 are arranged. When the angle formed by the arc is 120 °, the three abutting members 2 are arranged, thereby arranging the flange 4b. Although it is possible to provide the contact member 2 on the entire circumference in the circumferential direction of the root portion on the back surface, it is preferable to determine the shape of the contact member to be used in consideration of work efficiency and the like.

  Further, it is preferable that the contact between the abutting member 2 and the pressing portion A2 of the reinforcing member 1 is caused to abut at an inclined portion formed respectively as shown in FIG. By providing the inclined portion and abutting there, the abutment is reliably performed on the surface portion and the transmission of the tightening force is reliably performed.

  The tightening portion A3 provided at the end opposite to the pressing portion A1 formed at one end of the reinforcing member 1 is provided so as to protrude along the tube wall while maintaining a space between the tube wall. It is done. Then, by tightening the tightening portion A3 in the center direction of the pipe by the tightening member 3, a force acts in the direction of pressing the flange against the flange joint portion, particularly the root portion of the flange, and the flange joint portion. It is possible to improve the reinforcing effect and improve the airtightness of the flange joint with respect to external force.

  The principle of the force acting in the direction in which the flange is pressed against the flange joint, particularly the root portion of the flange, will be described in more detail with reference to FIG.

  By tightening the tightening portion A3 of the reinforcing member 1 in the center direction of the pipe by the tightening member 3, the inclined portion provided in the pressing portion A2 of the reinforcing member 1 and the inclined portion of the abutting member 2 come into contact with each other. . At this time, the pressing portion A1 of the reinforcing member 1 is in contact with the root portion of the rear surface of the flange 4a facing the pressing portion A2 side flange 4b, and this serves as a fulcrum of the lever, and the tightening portion A3 is connected to the tube. The force tightened in the center direction is converted into a force in a direction in which the pressing portion A2 presses the contact member 2 against the flange 4b.

  Here, by adjusting the tightening force in the tube center direction by the tightening member 3, it is possible to adjust the pressing force to the flange by the abutting member 2.

  In addition, when an external force acts on the flange joint in a direction in which the flange is expanded, the force acts on the tightening portion A3 of the reinforcing member 1 in the direction away from the center of the tube by the lever principle. However, in this case, since the force acts in the direction in which the tightening portion A3 is tightened in the central direction of the tube by the tightening member 3, it is possible to prevent the flange surface pressure from being lowered against the external force, It becomes possible to prevent leakage of the internal fluid.

  As shown in FIG. 1, the tightening force of the reinforcing member 1 on the flange joint portion is such that the pressing portion A1 of the reinforcing member 1 is in contact with the rear surface of the flange 4a and the abutting member 2 is in contact with the rear surface of the flange 4b. Act on the part. The portion where the pressing portion A1 is in contact with the back surface of the flange 4a and the portion where the contact member 2 is in contact with the back surface of the flange 4b are disposed closer to the pipe connecting portion than the position of the bolt and nut. It is difficult for a bending moment due to an external force to act, and deformation of the flange can be prevented. Since the flange joint is prevented from being deformed and the flange surface pressure is applied by the tightening member 3, it is possible to prevent the flange surface pressure from being reduced against an external force and to prevent leakage of internal fluid. It becomes.

  Here, since the pressing portion A1 has a configuration in which one end portion of the reinforcing member 1 is bent, even if the installation state of the reinforcing member 1 is slightly inclined, the pressing portion A1 is accurately brought into contact with the root portion of the back surface of the flange 4a. Can do.

  In addition, as a material of the said reinforcement member 1 and the contact member 2, it is preferable to use the steel which has rigidity and has a certain amount of elasticity, for example, steel materials, such as carbon steel and stainless steel. In a use environment where various external forces act, it is difficult to continue to apply a stable tightening force to the flange joint portion in the case of a weakly rigid or fragile object. Further, it is preferable that the rigidity is equal to or higher than that of the flange to be reinforced.

  Here, when there is a difference in strength between the two flanges to be joined, it is preferable to arrange the contact member 2 on the back surface of the low-strength flange. In this case, the abutting member 2 is formed in an arc shape and has a certain length in the circumferential direction of the tube, so that the tightening force by the tightening member 3 is dispersed and acts locally on the low-strength flange back surface. Can be prevented, and deformation of the flange can be prevented.

  A plurality of reinforcing members 1 are arranged at equal intervals in the circumferential direction of the flange. By providing a plurality at equal intervals in the circumferential direction, a tightening force acts evenly in the circumferential direction of the flange joint portion, and it is possible to suppress variations in the reinforcing effect due to the position of the flange joint portion. Thereby, it becomes possible to improve the airtight performance of the flange joint.

  FIG. 3 is a plan view showing an example of the arrangement of the reinforcing members 1 at the flange joint. As shown in FIG. 3, the reinforcing member 1 may be arranged at all positions between the bolts 5 provided on the flange, but the effect of the present invention can be obtained by arranging at least two of them on the diagonal line. It is possible. The arrangement position and the number of the reinforcing members 1 can be appropriately changed depending on the flange shape, the airtightness level of the flange, the use environment, and the like.

  Here, the plurality of reinforcing members 1 are arranged at equal intervals in the circumferential direction of the flange in order to apply a tightening force evenly to the flange joint surface. In other words, the equal interval with respect to the circumferential direction is the same as that the angles formed by the flange center positions of the reinforcing members 1 are equal.

  The fastening member 3 is preferably ring-shaped. The tightening member 3 is formed in a ring shape and tightened in a direction in which the radius of the ring shape shrinks, so that the tightening portions A3 of the plurality of reinforcing members 1 are approximately the same in the center direction of the pipe. It is possible to tighten with a tightening force of. In addition, it is preferable to provide a protrusion A5 for preventing the fastening member 3 from coming off at the tip of the fastening portion A3 of the reinforcing member 1. By providing the projection A5, it is possible to prevent the fastening member 3 before being tightened from coming off from the reinforcing member 1 in particular.

  Here, the tightening by the ring-shaped tightening member 3 is performed, for example, by tightening with a bolt or the like at a joint portion of a plurality of tightening members, or winding and tightening a wire or belt-shaped tightening member. Can be done. When tightening with the bolt or the like, or tightening with a wire or belt-shaped tightening member, means for arbitrarily adjusting the tightening force or tightening force, for example, tightening using a hydraulic pressure that can be adjusted to a predetermined tightening force It is preferable to use means (hydraulic nut or the like).

  By tightening the tightening member 3, the tightening portion A3 of the reinforcing member 1 is drawn toward the center of the pipe, and accordingly, the pressing portion A2 of the reinforcing member 1 and the respective inclined portions of the contacting member 2 are in close contact with each other, It becomes a surface contact state. Then, the force applied to the abutting member 2 is converted into a tightening force in a direction of pressing the flange joint portion by the inclination angle of the inclined portion, and the flange root portion can be pressed. By this tightening force, the surface pressure of the flange joint surface can be secured and the strength against leakage can be improved. Further, the external force acting on the flange joint is transmitted to the abutting member 2 and the reinforcing member 1, that is, the external force is transmitted without passing through existing bolts and nuts, thereby preventing flange deformation caused by the bolts and nuts. be able to.

  In addition, as a material of the said fastening member 3, it is preferable to use steel materials, such as carbon steel and stainless steel, for example.

  In addition, as shown in FIG. 1, the plurality of reinforcing members 1 arranged in the upper A4 region (auxiliary tightening portion A4) of the portion straddling the flange joint portion of each of the plurality of reinforcing members 1 are connected to the pipe. It is preferable to provide a ring-shaped auxiliary fastening member 4 for fastening in the center direction. As the shape and material of the auxiliary tightening member 4, the same material as that of the tightening member 3 can be used.

  Even when a plurality of reinforcing members 1 are installed by tightening the upper A4 region of the portion straddling the flange joint portion of the reinforcing member 1 with the auxiliary tightening member 4, tightening by the tightening member 3 is performed. The effect of preventing the displacement or dropping of the reinforcing member 1 before the tightening of the portion A3, and preventing the reinforcing member 1 from lifting when the tightening portion A3 is tightened by the tightening member 3, particularly the pressing portion A1 is prevented from lifting. Is possible. The auxiliary tightening member 4 can be installed and the installation position is not limited as long as it is a position where the reinforcing member 1, particularly the pressing portion A <b> 1 of the reinforcing member 1 can be pressed in the tube center direction.

  As described above, the case where the flange reinforcing jig of the present invention is configured by the plurality of reinforcing members 1, the abutting members 2, and the fastening members 3 has been described. It may be configured integrally. In this case, since the clearance at the time of arranging the reinforcing member 1 so as to straddle the flange joint portion is reduced, a little care is required at the time of placement, but the reinforcing effect of the flange joint portion is the same as in the above case. It is.

It is a figure which shows an example of schematic structure of the flange reinforcement jig | tool which concerns on this invention. It is a figure which shows an example of the preferable shape of the contact member in the case of providing the contact member which concerns on this invention in the circumferential direction perimeter of the root part of the flange 4b back surface, or its part. It is the top view which showed an example of arrangement | positioning of the reinforcement member in the flange junction part which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reinforcement member 2 Contact member 3 Fastening member 4 Auxiliary fastening member 5 Bolt

Claims (4)

A flange reinforcement jig at a flange joint of a pipe flange joint,
In a state where the flange reinforcing jig is in contact with a plurality of reinforcing members arranged at intervals in the circumferential direction of the flange so as to straddle the flange joint portion and the root portion of the flange portion rear surface, An abutting member pressed against the tube and a fastening member for fixing the plurality of reinforcing members to the tubular body,
The reinforcing member is in contact with the pressing portion A1 that is in contact with the root portion on the back surface of one flange portion, and the front surface is in contact with the back surface of the abutting member that is in contact with the root portion on the back surface of the other flange portion. A pressing portion A2 that presses against the pressing portion, and a tightening portion A3 that protrudes along the tube wall on the pressing portion A2 side,
The flange reinforcing jig, wherein the tightening member has a ring shape, and is configured such that each of the tightening portions A3 of the plurality of reinforcing members can be tightened in the center direction of the pipe. A flange reinforcement jig at a flange joint of a pipe flange joint,
The flange reinforcing jig comprises a plurality of reinforcing members arranged at intervals in the circumferential direction of the flange so as to straddle the flange joint portion, and a fastening member for fixing the plurality of reinforcing members to the pipe body. ,
The reinforcing member extends along the tube wall on the side of the pressing portion B2 and the pressing portion A1 that contacts the root portion on the back surface of one flange portion, the pressing portion B2 that contacts the root portion on the back surface of the other flange portion. And a tightening portion A3 projecting from
The flange reinforcing jig, wherein the tightening member has a ring shape, and is configured such that each of the tightening portions A3 of the plurality of reinforcing members can be tightened in the center direction of the pipe.   The ring-shaped auxiliary tightening member for tightening a plurality of reinforcing members arranged in the center direction of the pipe is further disposed on an upper portion of a portion straddling the flange joint portion of each of the plurality of reinforcing members. Or the flange reinforcement jig | tool of Claim 2.   A method for reinforcing a flange joint, comprising: reinforcing the flange joint using the flange reinforcing jig according to any one of claims 1 to 3.

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