JP7661336B2 - Method, system and program for managing gaskets - Google Patents

Description

The present disclosure relates to a technique for managing gaskets used, for example, in fastening piping systems.

The tightening torque and bolt axial force applied to the flange by the bolts are traditionally used for the tightening management of gaskets. The tightening torque and bolt axial force are tightening information related to the bolts that tighten the flanges.
Regarding the tightening of the gasket, a system is known that uses tightening surface pressure corresponding to the type of gasket and internal fluid, multiple tightening forces, bolt information, etc., to grasp the tightening torque (for example, Patent Document 1). Regarding the tightening of the bolt, a system is known that converts the strain generated in the bolt into data and visualizes the tightening state of the bolt (for example, Patent Document 2). Also, a system is known that measures the force applied to a part of the gasket by tightening using a sheet-type pressure sensor embedded inside the gasket (for example, Patent Document 3).

JP 2014-225219 A JP 2015-141345 A Patent No. 4699935

The reason why bolt tightening torque and axial force values are used to manage gasket tightening is that bolts are the means for tightening flanges, and the tightening force from the bolts can be easily determined by measuring the bolt strain.

However, a careful examination of the relationship between the bolts, flanges and gaskets revealed that the bolt tightening force acts on the flange, and only indirectly acts on the gasket via the flange. In other words, the flange is subjected to the load caused by the tightening of the bolts, and this load only acts on the gasket via the flange. The torque and axial force values applied to the bolts are loads acting on part of the flange, and cannot be said to represent the surface pressure acting on the gasket.

For this reason, gasket tightening management poses the following challenges:

a) The torque and axial force values obtained from the bolt are information about the bolt and cannot be said to measure the surface pressure received by the gasket.

b) In terms of the surface pressure that the gasket receives from the flange, the bolt torque value and axial force value are only indirect information and are only a guide to the surface pressure.

c) The bolt torque and axial force values are affected by the tightening condition of the bolts and flanges, and this tendency to fluctuate cannot be ignored.

When gasket surface pressure is estimated using torque values or axial force values measured with a torque wrench or bolt axial force meter, if the tightening condition of the bolts or flanges is affected, the relationship between the surface pressure applied to the gasket (= estimated surface pressure) and the surface pressure actually received by the gasket (= actual surface pressure) is as follows:
Estimated surface pressure ≠ actual surface pressure. Even if the measurement accuracy of torque and axial force values is improved, the estimated surface pressure and the actual surface pressure of the gasket do not match. It is not possible to grasp the surface pressure that the gasket receives.

Regarding this problem, the inventor has found that the change in shape of the gasket depends on the load applied between the flanges, and that observing this change in shape is beneficial in terms of managing the tightening of the gasket. Patent Documents 1 to 3 do not disclose or suggest this problem. Furthermore, the configurations disclosed in Patent Documents 1 to 3 are unable to solve this problem.

Therefore, based on the above problems and findings, an object of the present disclosure is to directly observe the change in shape of a gasket that is subjected to a load between flanges, and to use the observation results in managing the tightening of the gasket, thereby improving gasket management technology.

In order to achieve the above-mentioned object, according to one aspect of the management method disclosed herein, a gasket is used that changes shape due to the load received at a restraining portion restrained between flanges , and that has an inner cut whose long side extends along the periphery of a non-restraining portion adjacent to the restraining portion , and the method includes the steps of installing the gasket, applying a load to the gasket restrained between the flanges from between the flanges, and measuring the shape of the inner cut that has changed due to the load, and managing the tightening between the flanges based on the change in shape of the inner cut .

In this management method, the gasket may further be used such that opposing surfaces constituting the long side of the inner cut come into contact with each other due to a change in shape of the inner cut caused by the load.
This management method may further include a step of acquiring minimum point information from a change in shape of the inner cut.

In order to achieve the above-mentioned objective, according to one aspect of the management system disclosed herein, the system includes a measuring means for measuring the shape of an inner cut whose long side extends along the periphery of a gasket that is restrained between flanges and receives a load , a management server for generating management information for managing the tightening of the gasket based on changes in the shape of the inner cut , and an information presentation unit for presenting the management information.

In order to achieve the above-mentioned objective, according to one aspect of the program of the present disclosure , a computer is provided with a function for acquiring shape information of an inner cut whose long side extends along the periphery of a gasket that is restrained between flanges and receives a load , a function for generating management information for managing the tightening of the gasket based on the shape information, and a function for presenting the management information.

In this program, the inner cut is caused to come into contact with the opposing surfaces that make up the long side due to a change in shape of the inner cut caused by the load, and the computer further realizes a function of obtaining minimum point information from the change in shape of the inner cut.

According to the present invention, one of the following effects can be obtained:

(1) The load that the gasket receives from between the flanges causes distortion in the gasket, which can be manifested as a change in the shape of the inner cut of the gasket. The change in the shape of the inner cut can then be visualized and easily recognized.

(2) By observing the change in shape of the inner cut, the load applied to the gasket can be easily understood without being affected by the tightening condition of the bolt, and the tightening management of the gasket can be properly performed.

(3) The load applied to the gasket is estimated from the change in shape of the inner cut. The estimated load is equivalent to the actual surface pressure the gasket receives from the flange. This method can therefore improve the accuracy of gasket management, such as fastening management and gasket life prediction.

(4) The change in shape of the inner cut and the load estimated from this change in shape directly reflect the tightening state of the gasket, unlike the bolt torque value or axial force value. Therefore, by observing such change in shape and estimating the load, the accuracy of gasket management can be improved regardless of the skill of the worker.

Other objects, features and advantages of the technology disclosed herein will become more apparent with reference to the accompanying drawings and respective embodiments.

FIG. 2A is a plan view showing a gasket according to a first embodiment, and FIG. 2B is an enlarged perspective view showing a portion IB of FIG. 3A and 3B are diagrams illustrating a flange fastening portion according to the first embodiment. FIG. 3 is a diagram showing a cross-sectional end surface taken along line III-III in FIG. 2. FIG. 1A is an enlarged view of an inner cut, and FIG. 1B is a view showing a change in shape of the inner cut. 1A, 1B and 1C are diagrams showing modified examples of the inner cut. FIG. 1 is a diagram showing a gasket management system according to a first embodiment. FIG. 13 is a diagram showing a gasket management database. FIG. 1A is a diagram showing a comparative example, and FIG. 1B is a diagram showing settings of a shape observation unit. FIG. 13 is a diagram showing the relationship between the shape change and the load in Examples 1, 2, 3, and 4. FIG. 13 is a diagram showing the relationship between minimum points appearing in shape change and load. FIG. 13 is a diagram showing the relationship between the load and inflection points (without minimum points) that appear in the shape change. FIG. 10A is a diagram showing the shape of a gasket in accordance with Example 5, FIG. 10B is a diagram showing an example of the state before a load is applied, and FIG. 10C is a diagram showing an example of the state when a load of a predetermined value is applied. 13A and 13B are diagrams illustrating an example of shape observation according to the fifth embodiment.

First Embodiment
Fig. 1A shows a gasket 2 according to a first embodiment. The configuration shown in Fig. 1 is an example, and the present disclosure is not limited to such a configuration. In Fig. 1, an X-axis, a Y-axis, and a Z-axis are also shown as an example.

The gasket 2 is, for example, a sheet gasket made of a material that is a mixture of polytetrafluoroethylene tetrafluoroethylene resin (PTFE) and a filler. The gasket 2 may be made of a resin material other than PTFE or a rubber material. In addition, the gasket 2 may be made of a metal material, or a combination of a metal material and ceramic, a heat-resistant fiber material, or other material. Furthermore, the gasket 2 may be a spiral gasket 70 (FIG. 12), a flat gasket with a sheet of PTFE or graphite attached to the surface, a cam profile gasket with a groove formed on the surface of the gasket or a flange on the outer edge, etc.

This gasket 2 has a restrained portion 2-1 on the inner diameter side and a non-restrained portion 2-2 on the outer diameter side. The restrained portion 2-1 is an area that contacts the flanges 16-1, 16-2 (Figures 2 and 3) and receives a load F from between the flanges 16-1 and 16-2. In contrast, the non-restrained portion 2-2 is an area that does not contact the flanges 16-1 and 16-2.

Inner cuts 4-1, 4-2, 4-3, and 4-4 (hereinafter, simply referred to as inner cuts 4 unless a specific position is specified) are formed in the non-restrained portion 2-2. Each inner cut 4 is a through hole portion that penetrates the front and back of the non-restrained portion 2-2 of the gasket 2, and is a means for facilitating detection of changes in the shape of the gasket 2. Therefore, each inner cut 4 constitutes a shape observation portion for observing changes in the shape of the gasket 2 when a load F is applied to the restrained portion 2-1.

<Inner cut 4>
Fig. 1B shows an enlarged view of the inner cut 4 in part IB of Fig. 1A. This inner cut 4 is a through hole portion that penetrates the top and bottom surfaces of the gasket 2 with a constant arc-shaped long side length L and width W in the circumferential direction of the gasket 2. Each inner cut 4 has vertical surface portions 6-1, 6-2 that face each other with a constant width W, and inner peripheral surface portions 8-1 and outer peripheral surface portions 8-2 that face each other with the long side length L. The height D is the thickness of the gasket 2 before deformation.

To detect changes in the shape of the gasket 2, each inner cut 4 may be set at multiple locations on the gasket 2. It is preferable that there is no bias in the setting positions in order to avoid the effects of elastic interactions from the flanges 16-1, 16-2 and to increase the accuracy of detecting changes in shape. In this embodiment, each inner cut 4 is set at four locations on the X-axis and Y-axis, making it possible to detect changes in shape over a wide range.

<Flange fastening portion 12>
2 shows a cutaway view of the flange fastening portion 12 including the gasket 2. This flange fastening portion 12 is an example, and the present disclosure is not limited to the configuration shown in FIG.

This flange fastening portion 12 includes a flange 16-1 on the pipeline 14-1 side, a flange 16-2 on the pipeline 14-2 side (Figure 3), a gasket 2, a plurality of bolts 18 and nuts 20.

Flange 16-1 is integrally formed with the end face of pipeline 14-1, and similarly, flange 16-2 is integrally formed with the end face of pipeline 14-2. Flanges 16-1 and 16-2 have a larger diameter than pipelines 14-1 and 14-2, and multiple bolts 18 and nuts 20 are attached at predetermined angular intervals.

A gasket 2 is installed between the flanges 16-1, 16-2, inside the bolts 18 and nuts 20. The gasket 2 constitutes a sealing member for the flange fastening portion 12. Therefore, when the bolts 18 and nuts 20 are tightened, the gasket 2 receives a load F applied to the flanges 16-1, 16-2, and the pipelines 14-1, 14-2 are fastened and sealed.

The restraining portion 2-1 of the gasket 2 is sandwiched between the flanges 16-1, 16-2 and is in contact with and restrained by the flanges 16-1, 16-2. The non-restraining portion 2-2 protrudes around the restraining portion 2-1 and does not contact the flanges 16-1, 16-2, i.e., it is not restrained by the flanges 16-1, 16-2.

When the bolt 18 and nut 20 are tightened, the restrained portion 2-1 receives a load F from the flanges 16-1, 16-2, whereas the non-restrained portion 2-2 constitutes a free end that is not subjected to the load F.

When a load F acts on the restraint portion 2-1 from the flanges 16-1, 16-2, the load strain of the restraint portion 2-1 due to the load F spreads to the non-restraint portion 2-2 which is integral with the restraint portion 2-1, causing a change in shape in the inner cut 4. As a result, each inner cut 4 of the non-restraint portion 2-2 constitutes a site for detecting shape changes appearing in the gasket 2. If the load F acts in the Z-axis direction, strain will occur, for example, in the X-axis and Y-axis directions.

<Relationship between restraint portion 2-1, non-restraint portion 2-2, and flanges 16-1, 16-2>
Figure 3 shows a cross-sectional end surface taken along line III-III in Figure 2. The restrained portion 2-1 of the gasket 2 is sandwiched and restrained between the gasket seats 22 of the flanges 16-1 and 16-2. In contrast, the non-restrained portion 2-2 protrudes into the gap 24 between the flanges 16-1 and 16-2. The non-restrained portion 2-2 is integral with the restrained portion 2-1, is supported between the flanges 16-1 and 16-2, and is a free end that protrudes into the gap 24. In other words, the non-restrained portion 2-2 is in a cantilever state.

Strain and deformation that occur in the restrained portion 2-1 when it receives a load F from the flanges 16-1, 16-2 appear as a change in shape in the non-restrained portion 2-2. This change in shape can be easily observed from the inner cut 4. In other words, the change in shape of the gasket 2 that appears in the non-restrained portion 2-2 is strain or deformation caused by being pushed out from between the gasket seats 22, and represents the load that the restrained portion 2-1 of the gasket 2 receives from the flanges 16-1, 16-2.

<Observation of shape change of inner cut 4>
The inner cut 4 is formed in order to make the strain occurring in the unconstrained portion 2-2 apparent as a noticeable change in shape and to facilitate observation of the change.

A in Figure 4 shows the original shape of the inner cut 4. If the X axis is taken in the tangential direction of the gasket 2, the Y axis is taken at the center of the inner cut 4, and the Z axis is taken in the direction in which the load F is applied, when the load F is applied to the restraint portion 2-1 from the flanges 16-1, 16-2, a shape change (= strain) occurs in the spacing direction between the flanges 16-1, 16-2 and in the direction intersecting this spacing direction. This shape change includes a shape change in the circumferential direction of the gasket 2.

As shown in B of Figure 4, the non-constrained portion 2-2 expands by ΔY in the radial direction of the gasket 2 (indicated by arrow a), and the inner circumferential surface portion 8-1, the outer circumferential surface portion 8-2, and the vertical surface portions 6-1 and 6-2 also move in the radial direction of the gasket 2. At the same time, the width W of the inner cut 4 narrows to a width ΔW, as shown by the spacing distance between the inner circumferential surface portion 8-1 and the outer circumferential surface portion 8-2, as indicated by arrows b and c. These are shape changes of the gasket 2 that represent the load F applied to the constrained portion 2-1, i.e., the load that the gasket 2 is receiving. In this example, shape changes in the X-Y axes are illustrated, but it goes without saying that shape changes in the Z axis direction and thickness direction also appear in the shape of the inner cut 4.

Therefore, the strain generated in the restrained portion 2-1 and the non-restrained portion 2-2 when a load F is applied from the flanges 16-1, 16-2 is manifested as a change in the shape of the inner cut 4, making it easy to observe.

<Modification of inner cut 4>
The inner cut 4 is not limited to the form shown in Fig. 1B. Figs. 5A, 5B and 5C show modified examples of the inner cut 4. In Fig. 5, the same reference numerals are used to designate parts corresponding to those in Fig. 1B.

The inner cut 4 may be formed as parallel or non-parallel surfaces consisting of linear opposing surface portions 9-1 and 9-2 instead of the inner peripheral surface portion 8-1 and the outer peripheral surface portion 8-2 described above, as shown in A of Fig. 5, or may be formed as a square or fan shape consisting of four surfaces consisting of opposing surface portions 7-1, 7-2 and opposing surface portions 9-1 and 9-2, as shown in B of Fig. 5. Also, as shown in C of Fig. 5, by forming surface portions 9-11 and 9-12 on the opposing surface portion 9-1, the width between the opposing surface portions 9-1 and 9-2 may be partially different, for example, Wa, Wb (Wa<Wb). Even in such a form, the shape change that occurs in the non-constrained portion 2-2 when the load F is received by the constrained portion 2-1 can be easily detected from the inner cut 4.

In addition, a sensor member made of metal or resin may be installed in the space of the inner cut 4, and changes in the shape of the inner cut 4 may be detected from this sensor member.

<Gasket 2 Management Process>
The management process of the gasket 2 is an example of the management method of the present disclosure. This management process includes a process S1 of generating the constrained portion 2-1 and the non-constrained portion 2-2, a process S2 of applying a load F, a process S3 of acquiring shape information, and a process S4 of presenting the shape information, etc. S1 to S4 attached to each process exemplify the order of each process, and the cited terms are used merely for convenience.

Process S1 for generating the restraint portion 2-1 and the non-restraint portion 2-2: When the gasket 2 is placed between the flanges 16-1, 16-2, the portion of the gasket 2 that contacts the flanges 16-1, 16-2 becomes the restraint portion 2-1, and the portion of the gasket 2 that does not contact the flanges 16-1, 16-2 becomes the non-restraint portion 2-2. In other words, the restraint portion 2-1 and the non-restraint portion 2-2 of the gasket 2 are generated by being placed between the flanges 16-1, 16-2.

Step S2 of applying load F: A load F is applied to the restrained portion 2-1 of the gasket 2, which is restrained by the flanges 16-1 and 16-2, by tightening the flanges 16-1 and 16-2. In response to this load F, the restrained portion 2-1 of the gasket 2 is distorted, and the shape of the unrestrained portion 2-2 is changed.

Shape information acquisition process S3: Regarding the shape changes occurring in the non-restrained portion 2-2, the management server 30 (Figure 6) receives the detection output of the strain sensor 28 and acquires shape information of the inner cut 4.

Presentation process S4 of shape information, etc.: The management server 30 generates presentation information including shape information and presents it via the information presentation unit 32 (Figure 6).

In addition, the shape information acquired in the shape information acquisition step S3 may be subjected to N-th order differentiation (multiple-stage differentiation) to highlight the change points of the shape information. If the result of this processing is reflected in the presented information in the presentation step S4, the change points of the shape information can be clarified.

<Gasket Management System 26>
Fig. 6 shows a gasket management system 26 for executing the management process by information processing. The configuration shown in Fig. 6 is an example, and the present disclosure is not limited to such a configuration. In Fig. 6, the same parts as in Fig. 3 are given the same reference numerals.

This gasket management system 26 is equipped with a strain sensor 28, a management server 30 and an information presentation unit 32.

The strain sensor 28 measures the shape change appearing in the inner cut 4 of the gasket 2 and outputs a detection signal representing this shape change. This strain sensor 28 is an example of a means for detecting a shape change and converting it into an electrical signal. In addition to the strain sensor 28, a laser displacement meter, a camera, etc. may be used as a means for observing the shape change. The laser displacement meter shines laser light on the inner cut 4, detects the shape change of the inner cut 4 by the reflected light, and observes the amount of change. The camera captures an image of the inner cut 4, and the management server 30 detects the strain appearing in the inner cut 4 by the number of pixels and obtains shape information corresponding to the strain.

The management server 30 is composed of a computer with communications capabilities. This management server 30 comprises a processor 34, a memory unit 36, an input/output (I/O) unit 38, and a communications unit 40. The processor 34 executes the OS (Operating System) and management programs in the memory unit 36, and performs information processing for gasket management. The memory unit 36 includes a storage medium for storing the OS and management programs. A gasket management database (DB) 42 (Figure 7) is stored in this memory unit 36. Under the control of the processor 34, the communications unit 40 inputs and presents information in cooperation with a management terminal (not shown). The management terminal is also used to obtain shape information and write and read the gasket management DB 42.

In addition, the information presentation unit 32 presents shape information and judgment information including load under the control of the management server 30.

<Information processing of management server 30>
The information processing of the management server 30 includes the following steps:
The processes include a) inputting the detection output of the strain sensor 28, b) acquiring shape information of the inner cut 4, c) generating presentation information including the shape information, and d) presenting estimated information by the information presenting unit 32.

<Gasket Management DB42>
7 shows an example of the gasket management DB 42. The gasket management DB 42 is used for processing such as estimating a load from shape information. The gasket management DB 42 stores a gasket management file 44.

In this gasket management file 44, a gasket information section 46, an inner cut information section 47, a time information section 48, a load information section 50, a strain sensor information section 52, a detection information section 54, a judgment information section 56, and a history information section 58 are set.
The gasket information section 46 stores the identification information of the gasket 2 as well as specification information for identifying the gasket 2 .

The inner cut information section 47 stores shape information such as the shapes representing the inner cuts 4-1, 4-2, 4-3, and 4-4, as well as their placement positions and sizes.

The time information section 48 stores time information such as the measurement date and time.

The load information section 50 stores load information representing the load F applied between the flanges 16-1 and 16-2 by tightening the bolt 18.

The strain sensor information section 52 stores sensor information including the type and identification information of the strain sensors 28 (= 28-1, 28-2, 28-3, 28-4) that detect the shape.

The detection information section 54 stores the shape detection values obtained from each inner cut 4 (= 4-1, 4-2, 4-3, 4-4).

The judgment information section 56 stores estimated load information representing the load estimated from the shape information by the information processing of the management server 30.

The history information section 58 stores history information such as the acquisition of shape information and estimation processing.

Effects of the First Embodiment
According to the first embodiment, any one of the following effects can be obtained.

(1) Since the gasket 2 is provided with an inner cut 4, when a load F is applied to the restraint portion 2-1 from the flanges 16-1, 16-2, the strain generated in the restraint portion 2-1 can be visualized as a change in shape of the inner cut 4 of the non-restraint portion 2-2, and the change in shape corresponding to the load F can be easily observed from the inner cut 4.

(2) Shape information of the inner cut 4 is obtained from the detection output of each strain sensor 28 from the inner cut 4, and the load that the gasket 2 receives from the flanges 16-1, 16-2 can be estimated from the change in shape.

(3) The strain of the gasket 2 can be observed by the change in shape of the inner cut 4, and the load received by the gasket 2 can be estimated from the change in shape without being affected by the tightening torque or axial force of the bolt 18, and the tightening state of the gasket 2 can be determined.

(4) The tightening condition of the gasket 2 can be controlled with improved accuracy without being affected by the skill of the worker.

Second Embodiment
The method for managing the gasket 2 according to the second embodiment further includes an estimation step S5 based on minimum point information in addition to the management method according to the first embodiment.

In the estimation process S5 using minimum point information, the shape information including the shape changes appearing in the inner cut 4 includes minimum points (Figure 10) for specific loads, and the management server 30 can estimate the tightening state of the gasket 2 from the minimum points, i.e., the load (= surface pressure) that the gasket 2 receives from the flanges 16-1, 16-2.

<Advantages of the Second Embodiment>
According to the second embodiment, any one of the following effects can be obtained.

(1) The shape information can include minimum points as singular load information.

(2) By associating this minimum point with the load to be set, the minimum point can be confirmed from the shape information and set to a specific load.

(3) The load F, i.e., the surface pressure, can be estimated from the change in shape of the inner cut 4 to which the gasket 2 is subjected, making it easy to monitor and adjust the tightening state of the gasket 2.

An example of the gasket 2 of the present disclosure will be described together with a comparative example.
Comparative Example
8A shows a gasket 2 according to a comparative example. In this comparative example, a restraining portion 2-1 and a non-restraining portion 2-2 are set in a concentric shape with the same or nearly the same width.

In the gasket 2 of this comparative example, as shown in B of Figure 8, shape observation sections 60-1, 60-2, 60-3, and 60-4 are set at positions corresponding to the inner cut 4 of the embodiment. Each shape observation section 60-1, 60-2, 60-3, and 60-4 is arranged at angular intervals of a central angle of 90 degrees in the non-restraint section 2-2. The position of each shape observation section 60-1, 60-2, 60-3, and 60-4 is set at a position that does not overlap with the position of the bolt 18.

<Example 1-4>
The shape of the inner cut 4 of the gasket 2 according to the embodiment and the measurement results thereof are shown in Table 1.

Table 1 shows the shape of the inner cut 4 in Examples 1, 2, 3, and 4, the long side distance at the completion of tightening, and the minimum point load, as well as dimensional information and load information for the comparative example.

In Example 1, the long side length was 65 mm, the short side length (distance between long sides) was 1 mm, the circumference of gasket 2 was 327 mm, the long side length/circumference was 0.20, the aspect ratio was 65, the distance between long sides when tightening was completed was 0 mm, and the minimum point load was 145 kN.

In Example 2, with a long side length of 65 mm, a short side length (distance between long sides) of 3 mm, a circumference of gasket 2 of 327 mm, a long side length/circumference of 0.20, and an aspect ratio of 22, the long side distance at the time of tightening completion was 0 mm, and the minimum point load was 195 kN.

In Example 3, with long side length = 16 mm, short side length (distance between long sides) = 1 mm, circumference of gasket 2 = 327 mm, long side length/circumference = 0.05, and aspect ratio = 16, the distance between long sides at the time of completion of tightening = 0.6 mm, and the minimum point load = unidentifiable.

In Example 4, with long side length = 16 mm, short side length (distance between long sides) = 3 mm, circumference of gasket 2 = 327 mm, long side length/circumference = 0.05, and aspect ratio = 5, the distance between long sides at the time of completion of tightening was = 2.6 mm, and the minimum point load = unidentifiable.

And since there is no inner cut 4 in the comparative example, there is no corresponding data.

<Relationship between the long side distance of the inner cut and the load>
FIG. 9 shows the relationship between the load and the change in shape (change in the distance between the long sides) in Examples 1, 2, 3 and 4.

Regarding the relationship between the change in the long side distance and the load, n1 indicates the change in Example 1, n2 indicates the change in Example 2, n3 indicates the change in Example 3, and n4 indicates the change in Example 4.
Comparing these, it is clear that the shape changes of n1 and n2 are significant, and that by observing the shape changes, it is easy to identify the load applied to the gasket 2.

<Minimum point information in shape change>
In the case where the long side length L of the inner cut 4 is long, FIG. 10 shows the relationship between the load and the minimum point information appearing in the shape change, with the load on the horizontal axis and the strain on the vertical axis.

In FIG. 10, o1 indicates the shape change in the 0 (deg) direction, o2 indicates the shape change in the 45 (deg) direction, and o3 indicates the shape change in the 90 (deg) direction.
Thus, in Examples 1 and 2, there is a minimum point in the shape change.

<Inflection point information in shape change>
FIG. 11 shows the relationship between the load and the inflection points appearing in the shape change when the long side length L of the inner cut 4 is short.

In FIG. 11, p1 indicates the shape change in the 0 (deg) direction, p2 indicates the shape change in the 45 (deg) direction, and p3 indicates the shape change in the 90 (deg) direction.
When the long side length L of the inner cut 4 is short, the inner cut 4 does not come into contact with the inner circumferential surface portion 8-1 and the outer circumferential surface portion 8-2. Therefore, no minimum point occurs in the shape change. In other words, in Examples 3 and 4, only an inflection point is obtained in the circumferential strain in the 0 (deg) direction.

Effects of the embodiment
As is clear from these examples, by measuring the change in shape of the inner cut 4, the relationship between the change in shape and the load can be identified.

In all of Examples 1 to 4, inflection point information or minimum point information can be obtained, but if the long side length L of the inner cut 4 is increased, minimum point information can be obtained. Based on this minimum point information, the tightening state of the gasket 2, that is, the load (= surface pressure) that the gasket 2 receives from the flanges 16-1 and 16-2, can be estimated, and the tightening state of the flange tightening portion 12 can be judged.

Unlike torque management or bolt axial force measurement, this type of monitoring and measurement of shape change measures the shape change appearing in the inner cut 4 of the non-restrained portion 2-2 and can obtain shape information representing the load from the gasket 2. Therefore, the load can be estimated from the shape change of the gasket 2 due to the load F applied to the flanges 16-1, 16-2, without being affected by the bolts 18 or flanges 16-1, 16-2.

It was confirmed that the processing shape of the inner cut 4 can accommodate the gasket 2 to various diameters and thicknesses.

Example 5
FIG. 12 shows an example of the configuration of a gasket 70 according to a fifth embodiment.

This gasket 70 is, for example, a laminate of multiple members with different diameters arranged coaxially, and is a spiral-shaped gasket including an outer ring 701, a gasket body 702, and an inner ring 703. In this gasket 70, for example, only the inner ring 703, or the inner ring 703 and part or all of the gasket body 702, and part of the outer ring 701 are constrained portions 2-1 that abut against the gasket seat 22 (Figure 3) and receive a load F. In other words, in the gasket 70, part or all of the outer ring 701 becomes the non-constrained portion 2-2. In the gasket 70, the gasket body 702 deforms in response to the load F from the flanges 16-1 and 16-2, and this deformation causes strain in the outer ring 701.

The gasket 70 has one or more inner cuts 4 formed in a part of the outer ring 701. The inner cuts 4 are, for example, at a predetermined distance t of 5 mm from the outer edge of the outer ring 701.
In the fifth embodiment, for example, a change in shape Qa of the outer edge portion along the formation position of the inner cut 4 is observed to measure the shape of the inner cut 4 and to manage the surface pressure state of the gasket 70. The shape change Qa can be observed, for example, by using the strain sensor 28 of the gasket management system 26. The gasket management system 26 also calculates the shape of the inner cut 4 based on the measured shape change Qa. The management process of the fastening state of the gasket 70 can be performed in the same manner as in the above embodiment.

<Configuration of the gasket 70>
The outer ring 701 and the inner ring 703 are made of a metal material such as stainless steel, carbon steel, or titanium, and are formed into a ring of a predetermined thickness or a shape similar thereto. The gasket body 702 is formed by winding a laminate of a thin plate-like member made of a metal material, for example, and a buffer material (filler) such as graphite or fluororesin, in a spiral shape between the inner wall surface of the outer ring 701 and the outer wall surface of the inner ring 703. The laminate constituting the gasket body 702 is formed, for example, into a "V"-shaped cross section or a waveform similar thereto. The end faces of this laminate are fixed to the outer ring 701 and the inner ring 703 by spot welding, for example.

As shown in Fig. 12B, for example, the inner cut 4a of the outer ring 701 is open to a predetermined width before the load F from the flanges 16-1 and 16-2 is applied to the gasket body 702. When the load F acts through the gasket body 702, the outer ring 701 deforms partially or entirely at the opening, forming a closed inner cut 4b, as shown in Fig. 12C, for example.

Figure 13 shows the load [kN] on the horizontal axis and strain (shape change) on the vertical axis, and shows the measurement values of the circumferential shape change Qa (Figure 12) appearing on the outer edge of the outer ring 701 measured by the strain sensor 28.

In the measurement results, when the load on the gasket increases, for example, there is no significant change from when the load begins to be applied until a certain value is reached, and then when the load exceeds the certain value, a negative value is measured by the strain sensor. This indicates that a change in shape has occurred, indicating that the outer edge of the outer ring 701 has been compressed in the circumferential direction. The circumferential strain then reaches a minimum point, for example when the load is around 220 kN, and then increases in value in the positive direction.

<Effects of Example 5>
(1) By measuring the change in shape of the outer ring 701 of the spiral-wound gasket 70 sandwiched between the flanges 16-1 and 16-2, the surface pressure of the gasket 70 due to the load F can be determined.

(2) When using a spiral-wound gasket 70, unlike torque management or bolt axial force measurement, monitoring and measurement of shape change can be performed by measuring the shape change of the inner cut 4 from the shape change Qa occurring in the outer ring 701 , thereby obtaining a change representing the load F from the gasket 70. Therefore, the load F applied to the flanges 16-1 and 16-2 can be estimated from the shape change of the gasket 70 without being affected by the bolts 18 or flanges 16-1 and 16-2.

<Additional Notes>
Regarding the above-described embodiment and examples, the following supplementary notes are disclosed below.

(Appendix 1) A gasket to be installed between flanges of a flange fastening portion,
a restraint portion that is restrained between the flanges and receives a load;
A non-constrained portion that is not constrained between the flanges;
A through hole portion provided in the non-restrained portion;
wherein a change occurs in the through hole portion when the load is received.

(Appendix 2) A management system for managing a flange fastening portion having a gasket between flanges, comprising:
a restraint portion that is restrained between the flanges and receives a load, a non-restraint portion that is not restrained between the flanges, and a through hole portion provided in the non-restraint portion,
a gasket that changes the through hole portion when subjected to the load;
a measuring device that measures a change in the through hole portion with or without contacting the gasket;
a management server that acquires measurement information from the measuring instrument and generates management information including the fastening force between the flanges;
an information presenting unit that presents the management information in association with the gasket or the flange fastening portion;
A management system comprising:

(Appendix 3) A recording medium having a program for being realized by a computer recorded thereon,
a function of acquiring shape information including a change caused in a through-hole portion in a non-restrained portion of the gasket by being restrained between flanges and receiving a load from the flanges; and
a function of generating management information including a tightening force between the flanges based on the shape information;
a function of presenting the management information;
A recording medium on which a program for realizing the above on the computer is recorded.

[Other embodiments]

(1) In the above embodiment and examples, the initial fastening of the flange fastening portion 12 is exemplified by observing the shape change that occurs in the gasket 2 when a load is applied between the flanges, but this is not limited to the initial fastening of the flange fastening.

(2) The shape of the inner cut 4 described above is just one example, and the through hole portion may be an arc shape without a vertical surface portion 6, or a polygonal or rectangular shape with straight parallel surfaces or non-parallel surfaces.

(3) The above embodiment, comparative example, and example describe the load F applied to the gasket 2 when it is sandwiched between the flanges 16-1, 16-2, and the change in shape of the gasket 2. The load F applied to the gasket 2 is equivalent to the surface pressure that the gasket 2 receives from the flanges 16-1, 16-2, and there is no qualitative difference between the two. In other words, from the relationship between the load F applied to the gasket 2 and the shape change that appears in the inner cut 4, it is possible to estimate the surface pressure of the gasket 2 from the shape change.

(4) In the process of presenting shape information, etc. (S4) of the management process of the gasket 2, the management server 30 may generate presentation information by processing the acquired shape information such as multi-stage differentiation, and may present a display unit on the information presentation unit 32 (Figure 6) that clearly indicates change points.

As described above, the most preferred embodiment of the present disclosure has been described. The present disclosure is not limited to the above description. Various modifications and changes are possible for those skilled in the art based on the gist of the invention described in the claims or disclosed in the description for carrying out the invention. It goes without saying that such modifications and changes are included in the scope of the present disclosure.

According to the gasket management method, system, and program disclosed herein, it is possible to observe changes in the shape of the inner cut of a gasket that fastens flanges, and therefore the information can be used for management such as gasket tightening management and replacement without being affected by the tightening state of the bolts or flanges.

2, 70 Gasket 2-1 Restraint portion 2-2 Non-restraint portion 4, 4-1, 4-2, 4-3, 4-4, 4a, 4b Inner cut 6, 6-1, 6-2, Vertical surface portion 7-1, 7-2, 9-1, 9-2 Opposing surface portion 8-1 Inner surface portion 8-2 Outer surface portion 9-11, 9-12 Surface portion 12 Flange fastening portion 14-1, 14-2 Pipe line 16-1, 16-2 Flange 18 Bolt 20 Nut 22 Gasket seat 24 Gap 26 Gasket management system 28 Strain sensor 30 Management server 32 Information presentation portion 34 Processor 36 Memory portion 38 Input/output (I/O) portion 40 Communication portion 42 Gasket management database (DB)
44 Gasket management file 46 Gasket information section 47 Inner cut information section 48 Time information section 50 Load information section 52 Strain sensor information section 54 Detection information section 56 Judgment information section 58 History information section 60-1, 60-2, 60-3, 60-4 Shape observation section 701 Outer ring 702 Gasket body 703 Inner ring

Claims (6)

A gasket is used that has an inner cut whose shape changes in response to a load received by a restraining portion restrained between flanges and whose long side extends along a periphery of a non-restraining portion adjacent to the restraining portion,
installing the gasket ;
applying a load between the flanges to the gasket restrained between the flanges;
and measuring a shape of the inner cut that has changed due to the load.
A control method for controlling fastening between the flanges based on a change in shape of the inner cut . The management method according to claim 1, characterized in that the gasket is used such that opposing surfaces constituting the long side of the inner cut come into contact with each other due to a change in shape of the inner cut caused by the load. 3. The management method according to claim 2 , further comprising the step of acquiring minimum point information from a change in shape of the inner cut. A measuring means for measuring a shape of an inner cut having a long side extending along a periphery of a gasket that is restrained between flanges and receives a load ;
a management server that generates management information for managing fastening of the gasket based on a change in the shape of the inner cut ;
an information presenting unit that presents the management information;
A management system comprising: A function for acquiring shape information of an inner cut whose long side extends along the periphery of a gasket that is restrained between flanges and subjected to a load;
a function of generating management information for managing fastening of the gasket based on the shape information;
a function of presenting the management information;
A program to realize this on a computer . The inner cut is such that the opposing surfaces constituting the long side come into contact with each other due to a change in shape of the inner cut caused by the load,
The program according to claim 5 , further comprising a function of acquiring minimum point information from a change in shape of the inner cut by the computer.

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