Seal member diagnostic method

Abstract

To appropriately manage a replacement timing of a seal member with an objective and clear criteria without spoiling airtightness and liquid-tightness required for a structure.SOLUTION: A seal member diagnostic method includes: a limit permanent compression set acquisition step S3 of preparing a specimen having the same quality as a seal member 1, and acquiring a permanent compression set by which the performance of the specimen reaches a limit leakage flow rate required for a structure 2, as a limit permanent compression set; a deformation amount acquisition step S6 of releasing compression of the seal member 1 and acquiring a height of the seal member 1 in a non-compressed state; a permanent compression set calculation step S7 of calculating a permanent compression set of the seal member 1 by using the height of the seal member 1 acquired in the deformation amount acquisition step S6; and a determination step S8 of determining that the performance of the seal member 1 reaches a limit when the permanent compression set calculated in the permanent compression set calculation step S7 is equal to or more than the limit permanent compression set.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a seal member diagnostic method. [Background technology]

[0002] In structures that require airtightness and liquidtightness, sealing members made of rubber or the like are installed in a compressed state in gaps in doors and other openings in the structure. Seal members, which exhibit airtightness and liquidtightness (hereinafter referred to as "performance") when compressed, may deform over a long period of time, potentially making it impossible to maintain their performance. Therefore, the sealing members are inspected periodically, and their condition is diagnosed. Since the performance of a sealing member deteriorates as its compression set increases, it has been proposed to diagnose the condition of a sealing member based on its compression set (Patent Document 1).

[0003] In the method disclosed in Patent Document 1, a structure is opened, a sealing member that was actually used in the structure is obtained, and the thickness of the sealing member is measured. The measured thickness of the sealing member is used to calculate the compression set, and the condition of the sealing member is diagnosed based on the calculated compression set. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-173097 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not provide a clear standard for compression set to determine whether or not a seal member needs to be replaced. Therefore, in order to ensure that the seal member's performance is not significantly reduced, seal member users currently set unnecessarily strict compression set standards for seal members and manage the replacement timing of seal members. As a result, seal member replacements are becoming more frequent, leading to increased maintenance costs. Furthermore, the diagnostic method in Patent Document 1 requires the seal member itself, currently installed in the structure, to be removed and the diagnostic method is carried out over a long period of time, which poses a problem in that the airtightness and liquid-tightness of the structure cannot be ensured during the diagnostic process.

[0006] In order to solve this problem, the inventors prepared a test specimen having properties equivalent to those of a sealing member, and using this test specimen, obtained the compression set at which the critical leakage flow rate required for the structure was reached as the limit compression set. They also determined whether the sealing member needed to be replaced based on this limit compression set, and discovered that this would enable an objective and clear criterion for determining whether the time had come to replace the sealing member. This led to the present invention.

[0007] The present invention aims to appropriately manage the replacement timing of sealing members using objective and clear criteria without compromising the airtightness and liquidtightness required for structures. [Means for solving the problem]

[0008] The present invention is a sealing member diagnosis method for diagnosing the condition of a sealing member that is placed in a compressed state in the gap between a door and a frame at an opening in a structure and seals the gap, and includes a limiting compression strain acquisition process for preparing a test piece having properties equivalent to those of the sealing member and acquiring, as the limiting compression strain, the compression strain at which the performance of the test piece reaches the limiting leakage flow rate required for the structure; a deformation amount acquisition process for releasing the compression of the sealing member by opening the door and acquiring the deformation amount of the sealing member in an uncompressed state; a compression strain calculation process for calculating the compression strain of the sealing member using the deformation amount of the sealing member acquired in the deformation amount acquisition process; and a determination process for determining that the performance of the sealing member has reached its limit when the compression strain calculated in the compression strain calculation process is equal to or greater than the limiting compression strain.

[0009] The present invention also provides a method for diagnosing the condition of a seal member that is placed in a compressed state in the gap between a door and a frame at an opening in a structure and seals the gap, the method comprising the steps of: preparing a test piece having properties equivalent to those of the seal member; obtaining, as the limit compression set, the compression set at which the performance of the test piece reaches the limit leakage flow rate required for the structure; obtaining, as the limit compression stress, the compressive stress of the test piece that has reached the limit compression set; opening the door to release the compression of the seal member caused by the structure and pressing a load measuring jig into the seal member to measure the load acting on the seal member; using the load measured in the load measurement step to calculate the compressive stress generated in the seal member when compressed by the structure; and determining that the performance of the seal member has reached its limit when the compressive stress calculated in the compressive stress calculation step is less than the limit compressive stress. [Effects of the Invention]

[0010] According to the present invention, the replacement timing of a sealing member can be appropriately managed based on objective and clear criteria without impairing the airtightness and liquidtightness required for a structure. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing an outline of a structure including a sealing member. [Figure 2] (a) is a cross-sectional view of the initial sealing member 1 in an uncompressed state, (b) is a cross-sectional view of the sealing member 1 in a compressed state, and (c) is a cross-sectional view of the sealing member 1 in a state in which the compression has been released after being compressed for a predetermined time. [Figure 3] 3 is a flowchart of a seal member diagnostic method according to the first embodiment of the present invention. [Figure 4] FIG. 1 is a schematic diagram of a test device used in a limit compression set obtaining step. [Figure 5] 5 is an example of a graph showing the relationship between leakage flow rate and compression set obtained by a test using the test device shown in FIG. 4. [Figure 6] 1 is an example of a graph showing the change in compression set over time in a test specimen. [Figure 7] 1 is an example of a graph showing the relationship between time to reach limit compression set and temperature. [Figure 8] 6 is a flowchart of a seal member diagnostic method according to a second embodiment of the present invention. [Figure 9] FIG. 1 is a schematic diagram of a test device used in a limit compressive stress acquisition process. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] First Embodiment First, a seal member diagnostic method according to a first embodiment will be described with reference to FIGS.

[0014] Fig. 1 is a cross-sectional view showing an outline of a structure 2 equipped with a sealing member 1. As shown in Fig. 1, the structure 2 has a frame 3 that forms an opening 3a, and a door 4 that is attached to the frame 3. The door 4 is rotatable in the direction of the arrow shown in Fig. 1 to open and close the opening 3a. Fig. 1 shows the door 4 in a closed state. The opening 3a is, for example, an entrance and exit for workers to pass through.

[0015] The sealing member 1 is attached to the frame 3 along the periphery of the opening 3a. The sealing member 1 is made of, for example, chloroprene rubber, ethylene propylene diene rubber (EPDM), silicone rubber, or fluororubber, and is pre-formed in a factory and attached to the frame 3. The door 4 is provided with a protrusion 5 that protrudes toward the frame 3. When the door 4 is closed, the protrusion 5 is pressed into the sealing member 1. As a result, the sealing member 1 is compressed by the protrusion 5, and exhibits performance such as airtightness and liquidtightness.

[0016] In Fig. 1, the sealing member 1 is provided on the frame 3 and the protrusion 5 is provided on the door 4, but the protrusion 5 may be provided on the frame 3 and the sealing member 1 may be provided on the door 4. In other words, the sealing member 1 may be provided in a state compressed by the protrusion 5 in the gap between the frame 3 and the door 4 that opens and closes the opening 3a of the structure 2.

[0017] The seal member 1, which exhibits performance such as airtightness and liquid tightness when compressed, may be deformed by long-term compression and may no longer be able to exhibit the desired performance. If the seal member 1 is no longer able to exhibit the desired performance, it must be replaced. In order to determine whether it is time to replace the seal member, the seal member 1 is inspected periodically and the condition of the seal member 1 is diagnosed. This embodiment is used to diagnose the condition of the seal member 1.

[0018] The performance of the seal member 1 is interrelated with the compression set of the seal member 1. Therefore, in this embodiment, the condition of the seal member 1 is diagnosed based on the compression set. The compression set of the seal member 1 will be described with reference to FIG. 2. FIG. 2(a) is a cross-sectional view of the initial uncompressed seal member 1, FIG. 2(b) is a cross-sectional view of the seal member 1 in a compressed state by the protrusion 5 (a state in which the door 4 is closed), and FIG. 2(c) is a cross-sectional view of the seal member 1 in a state in which the compression has been released after being compressed by the protrusion 5 for a predetermined time (a state in which the door 4 is open).

[0019] As shown in Figure 2(c), even when the compression is released, the sealing member 1 does not completely return to its initial state (Figure 2(a)), and strain remains. The longer the compression time, the larger the strain remaining in the sealing member 1. The strain remaining in the sealing member 1 is the compression strain, and the compression strain is calculated using the following formula (1).

[0020] Compression set = (t0-t2) / t1 × 100 (1) however, t0: Height of seal member 1 from the reference point in the initial state t1: Push-in amount of protrusion 5 t2: Height from the reference point of the portion of the sealing member 1 where the protrusion 5 was pressed in when the compression was released

[0021] The height t0 of the sealing member 1 in its initial state is a value obtained by measuring the sealing member 1 after it has been installed in the structure 2 but before it is used (more specifically, after it has been attached to the frame 3 and before the door 4 is closed and the sealing member 1 is compressed; this is referred to as the "initial state"). For example, it is a value obtained by measuring the sealing member 1 during an inspection after it has been attached to the frame 3. The amount of depression t1 of the protrusion 5 is a value determined by the design of the mechanism that compresses the sealing member 1 (for example, the door 4 shown in Figure 1), and is a known value that represents the amount of depression of the protrusion 5 from the surface of the sealing member 1. In addition, by obtaining the height t2 of the sealing member 1 when the door 4 is opened and the compression is released after the structure 2 has actually been used, it is possible to obtain the compression set using equation (1).

[0022] In equation (1), t0 - t2 is the deformation amount of the sealing member 1 after volumetric contraction and compression of the sealing member 1. The height t0 in the initial state and the height t2 after the structure 2 is actually used can be measured by measuring the distance from the surface of the frame 3 as a reference point using, for example, a non-contact laser displacement meter or a 3D scanner. Measurement can be performed using any means that can measure the height of the sealing member 1 in its installed state without cutting or temporarily removing the sealing member 1 installed in the gap between the door 4 and the frame 3, but using a laser displacement meter allows for more accurate measurements.

[0023] Fig. 3 is a flowchart of a sealing member diagnostic method according to this embodiment. As shown in Fig. 3, the sealing member diagnostic method includes a preliminary evaluation step S1, a performance limit value calculation step S2, a limit compression set acquisition step S3, a lifespan prediction step S4, an on-site measurement step S5, a deformation amount acquisition step S6, a compression set calculation step S7, and a judgment step S8. Each step will be described in detail below.

[0024] (1.1 Pre-evaluation process) In the preliminary evaluation step S1, a preliminary evaluation of the compression set of the sealing member 1 is performed. Specifically, multiple test specimens with properties equivalent to the sealing member 1 to be diagnosed are prepared, and the test specimens are placed in constant temperature baths set at multiple (e.g., three) different temperature conditions to deteriorate the test specimens, and the change in compression set of each test specimen over time is determined. The test specimens are formed, for example, from the same material as the sealing member 1. Furthermore, the test specimens are placed in the constant temperature bath in a compressed state with a depression amount t1 of the protrusion 5, similar to the usage conditions of the sealing member 1. The compression set of the test specimens is calculated using the above-mentioned formula (1).

[0025] The temperature conditions are preferably below the usable temperature of the sealing member 1 and above the ambient temperature of the use of the sealing member 1. In this case, it is possible to accelerate deterioration of the test specimen and shorten the time required for the preliminary evaluation step S1. For example, if the usable temperature of the sealing member 1 is 120°C and the ambient temperature of the use of the sealing member 1 is room temperature (around 20°C), the temperature conditions in the preliminary evaluation step S1 can be 50°C, 70°C, or 90°C.

[0026] The reason for deteriorating the test specimen under multiple different temperature conditions is that the change in compression set over time under multiple different temperature conditions is necessary for life prediction using the Arrhenius plot described below. Three temperature conditions were set as an example, but the more parameters for the temperature conditions, the more accurate the life prediction using the Arrhenius plot can be improved.

[0027] In the preliminary evaluation step S1, in addition to temperature, humidity and external force (for example, stress) may also be included in the evaluation parameters.

[0028] (1.2 Performance limit calculation process) In the performance limit value calculation process S2, a performance test is conducted on the airtightness and liquidtightness of the test specimen, and a performance limit value is obtained that will allow the performance of the test specimen to reach the critical leak flow rate required for the structure 2 (see Figure 1) that will form the opening 3a. The performance required for the seal member 1 to be diagnosed is not uniformly determined, but differs individually depending on the critical leak flow rate required for the structure 2 in which it is installed. By obtaining a performance limit value corresponding to the critical leak flow rate required for the structure 2 for a test specimen that has properties equivalent to the seal member 1, it becomes possible to understand the performance limit value of the seal member 1 that corresponds to the critical leak flow rate required for the structure 2.

[0029] Fig. 4 is an example of a schematic diagram of a test apparatus 100 used in a performance test for the airtightness and liquidtightness of a test specimen. As shown in Fig. 4, the test apparatus 100 includes a test tank 10, a simulation frame 20 fixed to the test tank 10, and a simulation door 30 connected to the simulation frame 20. The test tank 10 and the simulation frame 20 define a storage space S for storing a fluid (e.g., water). An opening 20a is formed in the simulation frame 20, and the simulation door 30 can open and close the opening 20a.

[0030] The test specimen is mounted on the simulation frame 20 along the periphery of the opening 20a. The simulation door 30 is provided with a simulation protrusion 31, which is pressed into the test specimen when the simulation door 30 is closed. The simulation door 30 is connected to the simulation frame 20 via a bolt 21 and a nut 22. By rotating the bolt 21 and the nut 22 relative to each other, the amount by which the simulation protrusion 31 is pressed into the test specimen can be adjusted.

[0031] The testing device 100 also includes a tank 41 that stores a fluid, a supply passage 42 that supplies the fluid from the tank 41 to the storage space S, and a discharge passage 43 that discharges the fluid from the storage space S. The pressure of the fluid in the storage space S changes by opening and closing valves 44, 45 provided in the supply passage 42 and the discharge passage 43, respectively. A pressure gauge 46 is provided in the test tank 10, which can measure the pressure of the fluid in the storage space S. Therefore, the pressure of the fluid in the storage space S can be controlled to a desired value.

[0032] Below the opening 20a, there are provided a container 51 for receiving the fluid leaking from between the simulated protrusion 31 and the test body, and a measuring instrument 52 for measuring the weight of the fluid received by the container 51. The measuring instrument 52 is, for example, an electronic balance. The amount of fluid received by the container 51 per unit time is the flow rate of the fluid leaking from between the simulated protrusion 31 and the test body (hereinafter referred to as "leakage flow rate"), which corresponds to the performance of the test body.

[0033] In the performance test of the airtightness and liquid tightness of the test body in the performance limit value calculation step S2 described so far, a plurality of test bodies with different compression set strains accelerated and deteriorated in the pre-evaluation step S1 are used.

[0034] In the test apparatus 100 shown in FIG. 4, the simulated door 30 is arranged on the side of the storage space S with respect to the simulated frame 20 and has a structure that closes in the water pressure direction. The performance test of the test body can also be performed using a test apparatus in which the simulated door 30 is arranged on the opposite side of the storage space S with respect to the simulated frame 20 and has a structure that closes in the direction opposite to the water pressure direction.

[0035] (1.3 Limiting Compression Set Strain Acquisition Step) In the limiting compression set strain acquisition step S3, the compression set strain of the seal member 1 corresponding to the performance limit of the seal member 1 is acquired as the limiting compression set strain. By acquiring the limiting compression set strain corresponding to the limiting leakage flow rate required for the structure 2 in a test body having the same properties as the seal member 1, it becomes possible to grasp the limiting compression set strain of the seal member 1 corresponding to the limiting leakage flow rate required for the structure 2.

[0036] FIG. 5 is a graph showing the relationship between the leakage flow rate and the compression set strain obtained by a performance test using the test apparatus 100. In the graph shown in FIG. 5, the horizontal axis represents the compression set strain and the vertical axis represents the leakage flow rate. The performance test is performed using two test bodies with compression set strains CS1 and CS2 (where CS1 < CS2) that were accelerated and deteriorated in the pre-evaluation step S1, and the plots represent the measured values. The solid line is a straight line connecting the two plots.

[0037] The critical leakage flow rate L required for structure 2 (see Figure 1) lim is a value determined at the design stage of the structure 2 and is known. lim is the flow rate per unit time, and its unit is, for example, m 3 / hr. In Figure 5, the dashed line indicates the critical leakage rate L lim The critical leakage flow rate L lim The horizontal coordinate value of the intersection of the dashed line indicating the maximum leakage rate and the line connecting the plot of the measured values ​​is the limit compression set CS of the test specimen at which the limit leakage rate required for Structure 2 (see Figure 1) is reached. lim This completes the acquisition of the ultimate compression set of the test specimen.

[0038] FIG. 5 shows a case where there are two measured values, but when there are three or more measured values, an approximation line can be used that is drawn as close as possible to the measured values.

[0039] When conducting a performance test for airtightness and liquidtightness to create the graph shown in Figure 5, the fluid pressure in the storage space S and the amount of depression of the simulated protrusion 31 into the test specimen are set to be equivalent to the fluid pressure acting on the structure 2 (see Figure 1) and the amount of depression of the protrusion 5 into the seal member 1. This allows the test conditions for the test specimen to be closer to the specifications required for the seal member 1 in the structure 2, making it possible to more appropriately obtain the limit compression set.

[0040] (1.4 Life Prediction Process) In the life prediction step S4, the time until the limit compression set strain at the use environment temperature of the seal member 1 is reached is predicted as the life of the seal member 1. By predicting the life of the seal member 1 according to the use environment temperature, it is possible to appropriately set the timing for performing the on-site measurement step S5 described later. For example, as the use time of the seal member 1 approaches the predicted life, the timing for performing the on-site measurement step S5 can be set so as to increase the frequency of performing the on-site measurement step S5. Further, the remaining life from the use time of the seal member 1 to the predicted life can be estimated, and the timing for replacing the seal member 1 can be set without impairing the performance required for the structure. Thereby, the replacement timing of the seal member 1 can be more appropriately managed based on an objective and clear criterion.

[0041] In the life prediction step S4, the time-dependent change in the compression set strain in the test specimen obtained in the preliminary evaluation step S1 and the limit compression set strain of the test specimen obtained in the limit compression set strain acquisition step S3 are used.

[0042] First, the time until the compression set strain of the test specimen reaches the limit compression set strain is obtained for each of a plurality of different temperature conditions.

[0043] FIG. 6 is an example of a graph showing the time-dependent change in the compression set strain in the test specimen. The temperature conditions are T1, T2, T3 (where T1 < T2 < T3). In the graph shown in FIG. 6, the horizontal axis represents time and the vertical axis represents the compression set strain. The plots indicate the measured values, and the solid line indicates an approximation line drawn so as to pass as close as possible to the measured values. The straight line extending parallel to the horizontal axis indicates the limit compression set strain CS lim is shown.

[0044] The limit compression set strain CS lim The horizontal axis coordinate value of the intersection of the line indicating and the approximation line of the measured values under the temperature condition T1 is the time T1 lim at which the compression set strain of the test specimen reaches the limit compression set strain under the temperature condition T1. Similarly, the limit compression set strain CS limThe horizontal coordinate value of the intersection of the line representing the temperature condition T2 and the approximate line of the measured value at temperature condition T2 is the time T2 at which the compression set of the test specimen reaches the limit compression set. lim Limiting compression set CS lim The horizontal coordinate value of the intersection of the line representing the value of the compression set at temperature condition T3 and the approximate line of the measured value at temperature condition T3 is the time T3 at which the compression set of the test specimen reaches the limit compression set. lim is.

[0045] This completes the acquisition of the time it takes for the compression set of the test specimen to reach the limit compression set.

[0046] Next, the time to reach the limit compression set at the ambient temperature of use of the sealing member 1 is calculated. Fig. 7 is an example of a graph showing the relationship between the time to reach the limit compression set and the temperature. In the graph shown in Fig. 7, the horizontal axis is the reciprocal of the temperature (absolute temperature) and the vertical axis is the logarithm of the time. The plot shows the logarithm of the time calculated using the graph shown in Fig. 6, and the solid line is an approximation line drawn as close as possible to the plot.

[0047] The ambient temperature of the seal member 1 is a known value that is assumed during the design stage of the structure 2. Alternatively, the actual ambient temperature of the structure 2 may be measured and used instead of using the assumed value during the design stage. In Figure 7, the ambient temperature of the seal member 1 is indicated as T0. The vertical coordinate value of the intersection of the line representing the reciprocal of the ambient temperature T0 and the approximation line is the logarithm of the predicted time to reach the limit compression set at the ambient temperature T0.

[0048] This completes the prediction of the lifespan of the sealing member 1. The graph shown in Fig. 7 is called an Arrhenius plot. An Arrhenius plot is a graph obtained by acquiring changes in the physical properties of a test specimen that has been subjected to accelerated aging under high temperature conditions, and determining the test time required for each temperature condition to reach a certain physical property value.

[0049] By finding the regression equation for the approximated line in the Arrhenius plot and inputting the temperature conditions of the design (or actual) environment in which the seal member 1 will be used, or the temperature actually measured, it is possible to predict the life of the seal member 1 at the temperature of the environment in which the seal member 1 will be used. This makes it possible to appropriately set the timing for performing the on-site measurement step S5, which will be described later. This makes it possible to more appropriately manage the replacement timing of the seal member 1 based on objective and clear criteria.

[0050] (1.5 On-site measurement process) In the on-site measurement process S5, the dimensions of the sealing member 1 installed on the structure 2 are measured. Specifically, this process is divided into two time-series measurement processes: measurement immediately after the sealing member 1 is installed on the structure 2 and before use (more specifically, after the sealing member 1 is attached to the frame 3 and before the door 4 is closed and the sealing member 1 is compressed; this is referred to as the "initial state"); and measurement after actual use. For the measurement in the initial state, specifically, the height t0 of the sealing member 1 in the initial state shown in FIG. 2(a) is measured as the distance from a reference point set on the frame 3 (note that if the sealing member 1 is installed on the door 4, the height of the sealing member 1 from the reference point set on the door 4 is measured). For the measurement after actual use, specifically, the height of the recess 1a of the sealing member 1 in the state where the compression state is released as shown in FIG. 2(c) is measured as the distance from a reference point set on the frame 3, similar to the measurement in the initial state. These heights are measured using, for example, a non-contact laser displacement meter or a 3D scanner. Any means can be used to measure the height of the seal member 1 in its installed state without cutting or temporarily removing the seal member 1 provided in the gap between the door 4 and the frame 3, but using a laser displacement meter allows for more accurate measurements.

[0051] (1.6 Deformation amount acquisition process) In the deformation amount acquisition step S6, the deformation amount of the sealing member 1 installed in the structure 2 is acquired. The deformation amount of the sealing member 1 can be acquired from the height t0 of the sealing member 1 in the initial state obtained by measurement in the on-site measurement step S5 and the height t2 of the sealing member 1 in use when released from compression. The deformation amount of the sealing member 1 after compression is calculated as t0 - t2 in equation (1). The deformation amount of the sealing member 1 also includes the amount of volumetric shrinkage of the sealing member 1.

[0052] (1.7 Compression set calculation process) In the compression set calculation step S7, the compression set of the seal member 1 is calculated from the aforementioned formula (1) using the indentation amount t1 of the protrusion 5 and the deformation amount of the seal member 1 acquired in the deformation amount acquisition step S6. The indentation amount t1 of the protrusion 5 is the value of the indentation amount of the protrusion 5 from the surface of the seal member 1, which is determined by the design of the door 4 shown in Figure 1, and is a known value.

[0053] (1.8 Judgment process) In the determination step S8, the compression set of the sealing member 1 calculated in the compression set calculation step S7 is compared with the limit compression set of the sealing member 1 calculated from the performance test results in the limit compression set acquisition step S3. If the compression set of the sealing member 1 calculated in the compression set calculation step S7 is equal to or greater than the limit compression set, it is determined that the performance of the sealing member 1 has reached its limit (the sealing member 1 has reached the end of its life and needs to be replaced). Because the limit compression set is obtained in the limit compression set acquisition step S3 based on the limit leakage flow rate required for the structure 2, it is possible to accurately determine whether the performance of the sealing member 1 has reached its limit with respect to the limit leakage flow rate required for the structure 2. Therefore, the replacement timing of the sealing member 1 can be appropriately managed using objective and clear criteria.

[0054] In addition, in the judgment step S8, if the compression set of the sealing member 1 calculated in the compression set calculation step S7 is less than the limit compression set, it is judged that the performance of the sealing member 1 has not reached its limit (the sealing member 1 can still be used continuously).

[0055] According to the above embodiment, the following advantageous effects are achieved.

[0056] In this embodiment, it is determined that the performance of the seal member 1 has reached its limit when the compression set calculated using the height of the seal member 1 in an uncompressed state when the door 4 is open is equal to or greater than the limit compression set. The limit compression set is obtained based on the limit leakage flow rate required for the structure 2, so it is possible to accurately determine whether the performance of the seal member 1 has reached its limit with respect to the limit leakage flow rate required for the structure 2. Therefore, the replacement timing of the seal member 1 can be appropriately managed using objective and clear criteria.

[0057] Furthermore, in this embodiment, multiple test specimens having properties equivalent to those of the sealing member 1 are prepared, and the multiple test specimens are degraded under different temperature conditions to determine the time until the compression set of the test specimens reaches the critical compression set. Using the determined time and the ambient temperature of the sealing member 1, the time until the critical compression set of the sealing member 1 at the ambient temperature of use is predicted as the life of the sealing member 1. Therefore, the timing for measuring the sealing member 1 after actual use in the on-site measurement step S5 can be appropriately set based on the predicted life. This allows for more appropriate management of the replacement timing of the sealing member 1 using objective and clear criteria.

[0058] Second Embodiment Next, a seal member diagnostic method according to a second embodiment will be described with reference to Figures 8 and 9. Differences from the first embodiment will be mainly described below, and configurations that are the same as or equivalent to those described in the first embodiment will be denoted by the same reference numerals in the figures and will not be described again. In addition, a cross-sectional view showing an outline of a structure 2 equipped with a seal member 1 is the same as the cross-sectional view shown in Figure 1, and therefore will not be shown here.

[0059] FIG. 8 is a flowchart of a sealing member diagnostic method according to a second embodiment of the present invention. As shown in FIG. 8, this embodiment differs from the first embodiment in that a limit compressive stress acquisition step S13 is performed after the limit compressive strain acquisition step S3. Furthermore, this embodiment differs from the first embodiment in that the on-site measurement step S15 measures the load acting on the sealing member 1. Furthermore, this embodiment differs from the first embodiment in that a load acquisition step S16 and a compressive stress calculation step S17 are performed instead of the deformation amount acquisition step S6 and the compressive strain calculation step S7 in the first embodiment. Finally, this embodiment differs from the first embodiment in that the limit compressive stress and compressive stress are used in the determination step S18.

[0060] The preliminary evaluation step S1, the performance limit value calculation step S2, the limit compression set acquisition step S3, and the life prediction step S4 in this embodiment are the same as those in the first embodiment. Therefore, the limit compressive stress acquisition step S13, the on-site measurement step S15, the load acquisition step S16, the compressive stress calculation step S17, and the determination step S18 will be described in detail below.

[0061] (2.1 Critical compressive stress acquisition process) In the limit compressive stress acquisition step S13, the compressive stress when a test specimen with properties equivalent to the sealing member 1 reaches the limit compressive permanent strain is acquired as the limit compressive stress. When the sealing member 1 is crushed by the protrusions 5 and undergoes compressive deformation, stress is generated, and this compressive stress can be considered as resistance to fluid pressure. As the compressed state of the sealing member 1 continues, the amount of deformation increases over time, and the compressive stress decreases. By acquiring the limit compressive stress in advance, just like the limit compressive permanent strain, it becomes possible to determine the performance limit of the sealing member 1 according to the magnitude of the fluid pressure expected to be applied to the sealing member 1 in the structure 2.

[0062] 9 is a schematic diagram of a testing apparatus 200 used in the critical compressive stress acquisition step S13. As shown in FIG. 9, the testing apparatus 200 includes a support plate 210 that supports the test specimen, a pressing mechanism 230 that presses a load measuring jig 220 into the test specimen, and a measuring unit 240 that measures the load acting on the test specimen from the load measuring jig 220. The shape of the load measuring jig 220 is preferably the same as the shape of the protrusion 5 (see FIG. 1) on the structure 2. The pressing amount of the load measuring jig 220 is the value of the pressing amount of the protrusion 5 from the surface of the seal member 1, which is determined by the design of the door 4 shown in FIG. 1, and is a known value.

[0063] The compressive stress is calculated by the following formula (2).

[0064] Compressive stress = F / A (2) however, F: Load acting on the test piece from the load measuring jig 220 A: Indentation area of ​​the load measuring jig 220 on the test piece

[0065] The load F acting on the test specimen from the load measuring jig 220 is a value measured by the measuring unit 240, and the pressing area A of the load measuring jig 220 on the test specimen is a value that can be set arbitrarily by the user of the testing device 200. Therefore, by using the testing device 200, the compressive stress of a test specimen having properties equivalent to those of the sealing member 1 can be obtained from the formula (2).

[0066] The limit compressive stress of a test specimen having properties equivalent to those of the seal member 1 can be obtained by setting the test specimen, whose limit compressive strain has reached the limit compressive strain limit, in the testing device 200 and pressing the load measuring jig 220 into the test specimen. This makes it possible to determine the limit compressive stress of the seal member 1.

[0067] (2.2 On-site measurement process) In the on-site measurement step S15, a test is performed in which a load measuring jig 220 is pressed into the seal member 1 by a pressing amount determined by the design of a mechanism (for example, door 4 shown in FIG. 1) that compresses the seal member 1 provided in the structure 2, and the load acting on the seal member 1 at this time is measured. Specifically, the door 4 is opened from the state shown in FIG. 1 to release the compression of the seal member 1, and the load measuring jig 220 of the testing device 200 is pressed into the seal member 1 instead of the protrusion 5. At this time, the load acting on the seal member 1 is measured using the measuring unit 240, and the set value of the pressing area A is recorded.

[0068] (2.3 Load acquisition process) In the load acquisition step S16, the load that the seal member 1 provided in the structure 2 receives from the door 4 is acquired. The load that the seal member 1 receives from the door 4 corresponds to the load acting on the seal member 1, obtained by the test of pressing the load measuring jig 220 performed in the on-site measurement step S15. By regarding the load obtained by the pressing test using the load measuring jig 220 as the load that the seal member 1 receives from the door 4, the load that the seal member 1 receives from the door 4 can be acquired.

[0069] (2.4 Compressive stress calculation process) In the compressive stress calculation step S17, the compressive stress generated in the seal member 1 is calculated using the load that the seal member 1 receives from the door 4, which was measured in the load acquisition step S16. The compressive stress generated in the seal member 1 is calculated using the above-mentioned formula (2). In formula (2), the pressing area A of the load measuring jig 220 is a set value of the testing device 200.

[0070] (2.5 Judgment process) In the determination step S18, the compressive stress of the seal member 1 calculated in the compressive stress calculation step S17 is compared with the limit compressive stress calculated in the limit compressive stress acquisition step S13. If the compressive stress of the seal member 1 calculated in the compressive stress calculation step S17 is less than the limit compressive stress, it is determined that the performance of the seal member 1 has reached its limit (the seal member 1 has reached the end of its life and needs to be replaced). Because the limit compressive stress is obtained based on the limit leakage flow rate required for the structure 2, it is possible to accurately determine whether the performance of the seal member 1 has reached its limit with respect to the limit leakage flow rate required for the structure 2. Therefore, the replacement timing of the seal member 1 can be appropriately managed using objective and clear criteria.

[0071] In addition, in the judgment step S18, if the compressive stress of the sealing member 1 calculated in the compressive stress calculation step S17 is equal to or greater than the limit compressive stress, it is judged that the performance of the sealing member 1 has not reached its limit (the sealing member 1 can still be used continuously).

[0072] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0073] 1. Sealing member 1a Depression 2...Structure 3...Frame body 3a...Opening 4. Door 5...Protrusions 10. Test tank 20···Mock Frame 20a...opening 21 volts 22 Nut 30···Mock door 31...simulated protrusion 41 Tank 42...supply passage 43...Discharge passage 44 Valve 45···Valve 46 Pressure gauge 51...container 52...Measuring instrument 100··Test equipment 200··Test equipment 210...Support plate 220 Load measurement jig 230...Pushing mechanism 240...Measurement section A: Pressing area Llim: Limit leakage flow rate S... Storage space S1: Pre-evaluation process S2: Performance limit calculation process S3: Limit compression set acquisition process S13: Critical compressive stress acquisition process S4...Life prediction process S5: On-site measurement process S15: On-site measurement process S6...Deformation amount acquisition process S16...Load acquisition process S7: Compression set calculation process S17: Compressive stress calculation process S8...Judgment process S18...Judgment process T0...Using environment temperature T1...Temperature condition T2...Temperature condition T3...Temperature conditions t0: height t1: Push-in amount t2: Height

Claims

1. A method for diagnosing a condition of a seal member that is provided in a compressed state in a gap between a door that opens and closes an opening in a structure and a frame body and seals the gap, comprising: a limit compression set acquisition step of preparing a test specimen having properties equivalent to those of the sealing member, and acquiring, as a limit compression set, a compression set at which the performance of the test specimen reaches a limit leakage flow rate required for the structure; a deformation amount acquiring step of releasing the compression of the seal member by opening the door and acquiring a deformation amount of the seal member in an uncompressed state; a compression set calculation step of calculating a compression set of the sealing member using the deformation amount of the sealing member acquired in the deformation amount acquisition step; a determining step of determining that the performance of the sealing member has reached its limit when the compression set calculated in the compression set calculating step is equal to or greater than the limit compression set; A seal member diagnostic method comprising:

2. A method for diagnosing a condition of a seal member that is provided in a compressed state in a gap between a door that opens and closes an opening in a structure and a frame body and seals the gap, comprising: a limit compression set acquisition step of preparing a test specimen having properties equivalent to those of the sealing member, and acquiring, as a limit compression set, a compression set at which the performance of the test specimen reaches a limit leakage flow rate required for the structure; a limit compressive stress acquisition step of acquiring the compressive stress of the test specimen that has reached the limit compressive permanent set as the limit compressive stress; a load acquiring step of opening the door to release compression of the seal member caused by the structure, and pressing a load measuring jig into the seal member to acquire a load acting on the seal member; a compressive stress calculation step of calculating a compressive stress generated in the seal member when compressed by the structure, using the load measured in the load acquisition step; a determining step of determining that the performance of the sealing member has reached its limit when the compressive stress calculated in the compressive stress calculating step is less than the limit compressive stress; A seal member diagnostic method comprising:

3. 3. The seal member diagnostic method according to claim 1, further comprising: The method further comprises a life prediction step of preparing a plurality of test specimens, deteriorating the plurality of test specimens under different temperature conditions to determine the time until the compression set of the test specimens reaches the limit compression set, and predicting the time until the limit compression set is reached at the usage environment temperature of the seal member as the life of the seal member using the determined time and the usage environment temperature of the seal member. A seal member diagnostic method.

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