JP2014071057A - Deterioration determination device and deterioration determination method for vinyl chloride hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely make a determination on deterioration by calculating a remaining usable period while taking an actual use environment of a vinyl chloride hose into consideration.SOLUTION: A device 10 which makes a determination on deterioration of a vinyl chloride hose being used for an arbitrary period includes a storage section 24 which stores secular change characteristics of the plasticizer concentration of vinyl chloride hoses and the plasticizer concentration of a vinyl chloride hose as an object of determination, and a use period calculation section 22 which refers to secular change characteristics according to the plasticizer concentration and calculating an obtained use period as a use period of the vinyl chloride hose as the object of determination, and a deterioration prediction section 22 determines deterioration from the calculated use period.

Description

  The present invention relates to a deterioration determination device and a deterioration determination method for a vinyl chloride hose.

  A plasticizer is added to hard vinyl chloride used as a pressure-resistant member in a vinyl chloride hose, and a flexible vinyl chloride hose is provided. Since the embrittlement temperature of soft vinyl chloride is lowered when a plasticizer is added, the vinyl chloride hose has sufficient flexibility even at the lowest temperature in the installation environment.

  A large number of vinyl chloride hoses are used in various plants and facilities, and are often used particularly in outdoor environments, but are likely to deteriorate over time. The cause of deterioration of the hose is embrittlement of vinyl chloride, and the main cause of this embrittlement is volatilization of the plasticizer blended in the vinyl chloride material. That is, it is considered that the embrittlement temperature rises as the plasticizer volatilizes and the plasticizer concentration in the vinyl chloride material decreases.

  Patent Document 1 discloses a method for analyzing the degree of deterioration and remaining life of a polyvinyl chloride composition as follows. First, heat accelerated deterioration treatment is performed on a polyvinyl chloride composition consisting of the same polyvinyl chloride and plasticizer as the analysis target, and the tensile elongation change characteristics and tensile strength change characteristics with respect to the plasticizer content are pre-mastered. Get as. Then, the plasticizer content is calculated from the plasticizer extracted from the analysis target and collated with the tensile elongation change characteristics and tensile strength change characteristics, which are the master curves, to indirectly determine the tensile elongation ratio and tensile strength of the analysis target. taking measurement. Then, when the tensile elongation or tensile strength is less than 50% compared with the result of the sample before deterioration, it is determined that the remaining life of the hose is reached.

JP 2007-327877 A

  However, the conventional deterioration diagnosis method does not diagnose the remaining usable period in consideration of the actual use environment of the vinyl chloride hose, particularly the use environment at a low temperature.

(1) The device of the present invention for judging deterioration of a vinyl chloride hose that has been used for an arbitrary period of time shows the characteristics of the plasticizer concentration of the vinyl chloride hose over time and the plasticizer concentration of the vinyl chloride hose to be judged. A storage unit for storing, and a first use period calculation unit that calculates the obtained use period as a first use period of the vinyl chloride hose to be determined with reference to the time-dependent change characteristic according to the plasticizer concentration; It is characterized in that the deterioration is determined by the first use period.
(2) The method of the present invention for determining the deterioration of a vinyl chloride hose that has been used for an arbitrary period of time calculates the time-dependent change characteristic of the plasticizer concentration of the vinyl chloride hose and determines the plasticizer of the vinyl chloride hose to be determined The concentration is detected, the time-dependent change characteristic is referred to by the detected plasticizer concentration, the obtained use period is calculated as the first use period of the vinyl chloride hose to be judged, and the deterioration is caused by the first use period. It is characterized by determining.

  According to the present invention, the deterioration of the vinyl chloride hose can be determined based on the plasticizer concentration. Therefore, by grasping the plasticizer concentration corresponding to the minimum temperature assumed in the use environment of the hose, it is possible to perform the deterioration determination considering the use environment.

It is the structure schematic of an example of the vinyl chloride type hose which applies the degradation determination apparatus and degradation determination method of the vinyl chloride type hose by this invention. It is a characteristic diagram which shows the relationship between the plasticizer density | concentration and embrittlement temperature in a vinyl chloride type | system | group hose. It is a diagram which shows the time-dependent change characteristic of the plasticizer density | concentration of a vinyl chloride type hose. It is a diagram which shows the time-dependent change characteristic of the embrittlement temperature of a vinyl chloride type hose. It is the elements on larger scale of the outer peripheral part of a vinyl chloride type hose shown in FIG. It is a flowchart for calculating the maximum usable period of a vinyl chloride hose. It is a flowchart for calculating the remaining usable period of a vinyl chloride hose. It is a figure explaining the remaining use period computed from the embrittlement temperature of a vinyl chloride type hose. It is a figure explaining the remaining use period computed from the plasticizer density | concentration of a vinyl chloride type hose. It is a figure which shows the outline of the structural example of the deterioration determination apparatus of the vinyl chloride type | system | group hose by this invention. It is a figure which shows the example of a display of the scheduling of the hose replacement | exchange operation | work performed using the deterioration determination apparatus of the vinyl chloride-type hose by this invention.

Hereinafter, embodiments of a degradation determination method and degradation determination apparatus for a vinyl chloride hose according to the present invention will be described with reference to FIGS.
(First embodiment)
A method for determining deterioration of a vinyl chloride hose according to the first embodiment will be described.
FIG. 1 is a schematic structural view of an example of a vinyl chloride hose whose deterioration is determined by the deterioration determination method according to the present invention. The vinyl chloride hose has various structures, and the characteristics such as brittleness vary depending on the concentration of the plasticizer. Therefore, the vinyl chloride hose determined by the present invention is limited to the structure shown in FIG. Is not to be done. Therefore, the present invention can also be applied to vinyl chloride hoses having a plurality of different characteristics used in plants and equipment.
In the following description, the vinyl chloride hose is also simply referred to as a hose.

  As shown in FIG. 1, the vinyl chloride hose 1 uses hard vinyl chloride 2 as the outermost layer, and maintains the pressure resistance of the vinyl chloride hose 1. Further, rubber 3 is used for the innermost layer, and water resistance is maintained. Soft vinyl chloride 4 is used for bonding the innermost rubber layer 3 and the outermost hard vinyl chloride layer 2 together.

  Many plasticizers are used in the inner layer rubber 3 and the soft vinyl chloride 4, and the embrittlement temperature is low. However, since the hard vinyl chloride 2 of the outermost layer has a certain degree of strength from the viewpoint of maintaining pressure resistance, the concentration of the plasticizer is lower than that of the inner layer and the intermediate layer, and the embrittlement temperature becomes higher. Yes. Therefore, the deterioration determination of the vinyl chloride hose 1 is performed by paying attention to the outermost hard vinyl chloride 2. That is, in the first embodiment, the life of the hard vinyl chloride 2 is the life of the vinyl chloride hose 1.

(Degradation judgment procedure)
The deterioration determination method of the first embodiment specifies the maximum usable period of the same material as the deterioration determination target hose, specifies the actual use period of the hose, and the difference between the maximum usable period and the actual use period. Is calculated as the remaining usable period, that is, the remaining life. Therefore, in this embodiment, characteristic diagrams I to III shown in FIGS. 2 to 4 are created in advance, and the remaining life is accurately calculated using these characteristic diagrams I to III.

(1) Specific diagram I
For a new vinyl chloride hose 1 made of the same material as the hose to be deteriorated, the plasticizer concentration and the embrittlement temperature of the hard vinyl chloride 2 in the outermost layer are measured. Similarly, for the vinyl chloride hose 1 exposed outdoors only for a predetermined period, the plasticizer concentration and the embrittlement temperature of the hard vinyl chloride 2 of the outermost layer are measured.

  From the measured values of the plasticizer concentration and the embrittlement temperature, a characteristic diagram representing the relationship between the plasticizer concentration and the embrittlement temperature as shown in the characteristic diagram I of FIG. 2 is obtained. FIG. 2 is a characteristic diagram in which the horizontal axis represents the plasticizer concentration and the vertical axis represents the embrittlement temperature. The smaller the plasticizer concentration, the higher the embrittlement temperature. Based on the characteristics shown in FIG. 2, the plasticizer concentration corresponding to the lowest temperature (referred to as the environmental minimum temperature) in the environment where the hose that is the target of deterioration determination is used is defined as the lower limit concentration.

(2) Specific diagram II
A characteristic diagram II as shown in FIG. 3 representing the relationship between the period of use of the outermost hard vinyl chloride 2 and the plasticizer concentration is obtained. The calculation of the characteristic diagram II will be described later. FIG. 3 is a characteristic diagram in which the horizontal axis indicates the period of use, and the vertical axis indicates the plasticizer concentration. The longer the usage period, the lower the plasticizer concentration. With reference to the characteristic diagram II in FIG. 3, the plasticizer concentration corresponding to the above-mentioned minimum environmental temperature, that is, the period of use corresponding to the lower limit concentration is specified. This period of use is the maximum usable period when the deterioration limit of the vinyl chloride hose 1 is evaluated by the plasticizer concentration, and this period is Tmax1.

  And the plasticizer density | concentration of the hard vinyl chloride 2 of the outermost layer of the vinyl chloride type | system | group hose 1 which deteriorated after using for arbitrary periods is measured, Based on the characteristic diagram II of FIG. The usage period Tuse is specified. The difference between the specified use period Tuse and the maximum usable period Tmax1 is the remaining usable period Tres when the plasticizer concentration of the deteriorated vinyl chloride hose 1 is evaluated.

(3) Specific diagram III
A characteristic diagram like the characteristic diagram III in FIG. 4 showing the relationship between the embrittlement temperature of the vinyl chloride hose 1 and the period of use is obtained. The calculation of the characteristic diagram III will be described later. FIG. 4 is a characteristic diagram in which the horizontal axis indicates the period of use, and the vertical axis indicates the embrittlement temperature, and shows a tendency that the embrittlement temperature increases as the use period becomes longer. The above-mentioned minimum environmental temperature is the embrittlement temperature corresponding to the deterioration limit of the vinyl chloride hose 1, and the use period corresponding to this temperature is the maximum usable period Tmax2 when the embrittlement temperature is evaluated.

  And the embrittlement temperature of the hard vinyl chloride 2 of the outermost layer of the vinyl chloride hose 1 deteriorated after use for an arbitrary period is measured, and it corresponds to the measured embrittlement temperature based on the characteristic diagram III of FIG. The usage period Tuse is specified. The difference between the specified use period Tuse and the maximum usable period Tmax2 is the remaining usable period Tres of the vinyl chloride hose 1.

An outline of the procedure for calculating the remaining life using the above characteristic diagrams I to III will be described.
(1) Specify the minimum temperature in the environment where the hose that is subject to deterioration determination is used, specify the maximum usable period at this minimum temperature, specify the usage period of the hose that is subject to deterioration determination, and use this The remaining life is calculated based on the difference between the period and the maximum usable period.

(2) It is known that the deterioration of a vinyl chloride hose depends on the embrittlement temperature and the plasticizer concentration of the hose. Therefore, the correlation between the plasticizer concentration and the use period is acquired in advance as a characteristic diagram II (see FIG. 3), and the correlation between the embrittlement temperature and the use period is acquired in advance as a characteristic diagram III (see FIG. 4). . When specifying the maximum usable period from the embrittlement temperature, the maximum usable period Tmax2 can be specified with reference to the characteristic diagram III at the lowest environmental temperature.

(3) When specifying the maximum usable period from the plasticizer concentration, it is necessary to specify the plasticizer concentration at the lowest environmental temperature. Therefore, in the first embodiment, the correlation between the plasticizer concentration and the embrittlement temperature is acquired as a characteristic diagram I (see FIG. 2), and the plasticizer concentration is obtained by referring to the characteristic diagram I at the lowest environmental temperature. This concentration is set as the lower limit concentration under the minimum environmental temperature, and the maximum usable period Tmax1 is specified with reference to the characteristic diagram II at the lower limit concentration.

(4) The smaller one of the maximum usable periods Tmax1 and Tmax2 specified in this way is set as the maximum usable period Tmax, and the maximum usable period Tmax is stored as a table in association with the hose to be subjected to deterioration determination, for example. Keep it. The hose subject to deterioration determination is classified according to the material and size to be used, and the maximum usable period Tmax for each type of hose is stored.
(5) The maximum usable period Tmax is specified based on the hose subject to deterioration determination.
(6) When the use period Tuse of the hose subject to deterioration determination is clear, the difference between the maximum usable period Tmax and the use period Tuse is calculated as the remaining use period Tres, that is, the remaining life.

(7) If the period of use of the deterioration determination target hose is unclear, cut out the test piece from the target hose. When the maximum usable period of the hose is specified from the plasticizer concentration, the plasticizer concentration is specified from the test piece, and the estimated usage period TermF is specified by referring to the characteristic diagram II with the plasticizer concentration. When the maximum usable period of the hose is specified from the embrittlement temperature, the embrittlement temperature is specified from the test piece, and the estimated use period TermD is specified by referring to the characteristic diagram III at the embrittlement temperature. Then, the difference between the maximum usable period Tmax and the estimated usable period TermF or the difference between the maximum usable period Tmax and the estimated usable period TermD is calculated as the remaining usable period Tres, that is, the remaining life.

A method for measuring the embrittlement temperature of the vinyl chloride hose 1 and the plasticizer concentration necessary for obtaining the characteristic diagrams I to III described with reference to FIGS.
[A: Measurement method of embrittlement temperature]
The embrittlement temperature test method measures the embrittlement temperature of a polymer material by giving a predetermined impact to a cantilever test piece placed in a constant temperature test chamber. This test method is a general method used to evaluate the effect produced by phase separation of plasticizers at low temperatures.
The embrittlement temperature is measured according to JIS standard K7216. The embrittlement temperature test device is a device that maintains a test piece held in a cantilever manner on a test piece gripper at a predetermined temperature in a test tank, gives an impact to the test piece with a hammer and observes the state of fracture at that time. .

The measurement procedure of the embrittlement temperature using the above embrittlement temperature test apparatus is shown below.
(Step A1) Cut out the outermost layer of hard vinyl chloride 2 from the vinyl chloride hose, and a test piece having a length of 38 mm, a width of 6 mm, and a thickness of 2 mm, or a length of 20 mm, a width of 2.5 mm, and a thickness of 1.6 mm Test pieces are made by machining into test pieces.
(Step A2) Ethanol is added as a heat transfer medium to the test tank and adjusted to a predetermined temperature.
(Step A3) The test piece is attached to the test piece gripping tool of the embrittlement temperature test apparatus with a torque of 2 kgf / cm (0.19 J) using a torque driver.

(Step A4) The hammer is rotated at a speed specified by JIS to strike the test piece, and then the presence or absence of destruction is confirmed.
(Step A5) The test temperature is increased every 5 ° C., 10 or more test pieces are tested for each temperature, and the number of fractures at each temperature is recorded.
(Step A6) The embrittlement temperature (Tb) is obtained using the following equation.
Tb = Th + ΔT (S / 100−1 / 2)
here,
Tb: embrittlement temperature (° C)
Th: Maximum temperature at which all test pieces break (° C) ΔT: Test temperature interval (° C)
S: Percentage of the total number of fractures at each measurement temperature from the lowest temperature at which all specimens do not break to Tb

[B, C: Measuring method of plasticizer concentration]
There are two methods for measuring the plasticizer concentration, the Soxhlet extraction method and the heating reflux method, which can be measured by either method. The measuring method is measured according to JIS standard K6229.

[B: Soxhlet extraction method]
The test piece is Soxhlet extracted with a solvent, and the solvent is removed from the extract to obtain the extraction amount. The average value of the two measurements is taken as the quantitative value.

The procedure for measuring the plasticizer concentration by the Soxhlet extraction method is shown below.
(Step B1) The outermost layer of hard vinyl chloride 2 is cut from the vinyl chloride hose 1 and cut into pieces of 2 mm square or smaller. More preferably, freeze pulverization is used. Average data can be easily obtained by freeze grinding. 3-5 g of this is weighed.
(Step B2) The flask is dried at 100 ° C., allowed to cool in a desiccator, and then weighed.

(Step B3) The weighed test piece is put into a cylindrical filter paper and then put into an extraction device, and the heating rate is adjusted so that the extraction solvent fills the extraction cup 10 to 20 times per hour. The extraction time is 16 hours. As the extraction solvent, acetone, n-hexane, chloroform, carbon tetrachloride, methanol, ethanol, diethyl ether, or the like is used. It is desirable to use different solvents depending on the type of plasticizer.
(Step B4) After completion of extraction, heating is stopped and cooling is performed. Remove the receiver flask from the extractor and attach a distillation head and cooler to distill off the solvent.

(Step B5) The extract in the flask is dried for 2 hours in a dryer at 100 ° C. After cooling in a desiccator, the mass of the flask is weighed.
(Step B6) The entire procedure is performed using the same apparatus and the same amount of extraction solvent without using the test piece, and the increase in flask mass is determined.
(Step B7) The plasticizer concentration (%) is obtained using the following equation.
Plasticizer concentration (%) = {(m2-m1-m3) / m0} × 100
Where m0: test piece mass (g)
m1: Mass of the flask only (g)
m2: Mass of the flask containing the extract (g)
m3: Flask mass increase in blank test (g)

[C: Heating reflux method]
The plasticizer concentration can also be measured using a heating reflux method. Hereinafter, a method for measuring the plasticizer concentration of vinyl chloride using this heating reflux method will be described.
First, the test piece is extracted by refluxing with a solvent. The solvent is removed from the test piece, and the extraction amount is determined from the mass difference between the test pieces before and after extraction. The average value of the two measurements is taken as the quantitative value.

The procedure for measuring the plasticizer concentration by the heating reflux method is shown below.
(Step C1) The outermost layer of hard vinyl chloride 2 is cut out from the vinyl chloride hose and cut into strip-shaped test pieces having a thickness of 2 mm or less. One test piece mass shall be 90-110 mg. Take 4-6 of these and weigh.
(Step C2) An extraction solvent and a test piece are put together in a flask, a condenser is attached, and reflux extraction is performed for 60 minutes. As the extraction solvent, acetone, n-hexane, chloroform, carbon tetrachloride, methanol, ethanol, diethyl ether, or the like is used. It is desirable to use different solvents depending on the type of plasticizer.

(Step C3) After completion of the extraction time, the heating is stopped and the mixture is allowed to cool. Thereafter, the test piece after extraction and the extract are separated using a 150 μm sieve.
(Step C4) The test piece after completion of extraction is dried in a dryer at 100 ° C. until the mass change for 10 minutes becomes 0.1 mg or less.
(Step C5) After standing to cool in a desiccator, the test piece mass after extraction is weighed.
(Step C6) The plasticizer concentration (%) is obtained using the following equation.
Plasticizer concentration (%) = {(m4-m5) / m4} × 100
Here, m4: test piece mass before extraction (mg)
m5: Test piece mass after extraction (mg)

[D: Calculation method of maximum usable period]
A method for calculating the maximum usable period of the vinyl chloride hose 1 will be described with reference to FIGS.
(Step D1) The hard vinyl chloride 2 as the outermost layer is cut out from a new vinyl chloride hose 1. Further, as shown in FIG. 5, the outermost layer of hard vinyl chloride 2 is divided into two at the cut surface 5, the front side 6 and the inner side 7 in contact with the soft vinyl chloride 4.
The front side 6 is in an environment where it is directly exposed to ultraviolet rays and heat compared to the inner side 7. Therefore, the volatilization of the plasticizer is likely to proceed. Also, depending on the period of use, the plasticizer concentration may increase because the plasticizer moves from the inside to the surface and oozes out. Thus, since the distribution of the plasticizer concentration is observed depending on the measurement location, the measurement is performed by dividing the surface into the surface side 6 where the plasticizer concentration is likely to change and the inside 7 where the plasticizer concentration is relatively difficult to change.

  (Step D2) With respect to the surface side 6 and the inner side 7 of the hard vinyl chloride 2 as the outermost layer, the embrittlement temperature (° C.) is measured according to the measurement method described above. However, when the embrittlement temperatures of the front side 6 and the inner side 7 are different, the higher value is used.

  (Step D3) About the surface side 6 and the inner side 7 of the hard vinyl chloride 2 of the outermost layer, the plasticizer concentration (%) is measured according to the measurement method described above. However, if the plasticizer concentrations on the front side 6 and the inner side 7 are different, the lower value is used.

  (Step D4) The outermost layer hard vinyl chloride 2 is cut out from the vinyl chloride hose 1 used for a predetermined period. Further, as shown in FIG. 5, the outermost layer of hard vinyl chloride 2 is divided into two parts: a surface side 6 and an inner side 7 in contact with the soft vinyl chloride 4.

  (Step D5) As in the case of a new article, the embrittlement temperature (° C.) is measured for the surface side 6 and the inner side 7 of the hard vinyl chloride 2 of the outermost layer according to the measurement method A described above. However, when the embrittlement temperatures of the front side 6 and the inner side 7 are different, the higher embrittlement temperature value is used.

  (Step D6) As in the case of a new article, the plasticizer concentration (%) is measured for the surface side 6 and the inner side 7 of the hard vinyl chloride 2 of the outermost layer according to the above-described measuring method B or C. However, if the plasticizer concentrations on the front side 6 and the inner side 7 are different, the lower plasticizer concentration value is used.

(Step D7) The new embrittlement temperature and the embrittlement temperature of the vinyl chloride hose 1 used for a predetermined period are plotted against the use period, and the characteristic diagram III described in FIG. 4, ie, the embrittlement temperature of the hose 1 is plotted. And the relationship between the period of use.
Here, it is assumed that in the new hose 1, the value of the plasticizer concentration is a certain value, and therefore the embrittlement temperature is also a certain value. The use period of the new vinyl chloride hose 1 is set to 0.
(Step D8) From this characteristic diagram III, the maximum usable period Tmax2 until the embrittlement temperature reaches the environmental minimum temperature is obtained.

(Step D9) For the new hose 1 and the hose used for a predetermined period, the relationship between the plasticizer concentration and the embrittlement temperature is plotted, and the characteristic diagram I described in FIG. 2, that is, the relationship between the plasticizer concentration and the embrittlement temperature. Is obtained.
(Step D10) From FIG. 2, the plasticizer concentration when the embrittlement temperature reaches the environmental minimum temperature is determined, and this is set as the lower limit concentration.

(Step D11) The new plasticizer concentration and the plasticizer concentration of the vinyl chloride hose 1 used for a predetermined period are plotted against the use period, and the characteristic diagram II described in FIG. Find the relationship between plasticizer concentration and duration of use.
(Step D12) From FIG. 3, the maximum usable period Tmax1 until the lower limit concentration obtained in (Step D10) is reached is obtained.
(Step D13) The maximum usable period Tmax2 obtained in (Step D12) is compared with the maximum usable period Tmax2 obtained in (Step D12), and the shorter one is used as the maximum usable period Tmax actually used for the determination of deterioration. adopt.
That is, Tmax = min (Tmax1, Tmax2).

  In this way, the maximum usable period Tmax is calculated for each hose type subject to deterioration determination, and the hose type and the maximum usable period are stored in a correspondence table format, for example. For example, the maximum usable period TmaxP for the hose type P and the maximum usable period TmaxQ for the hose type Q are tabulated and stored.

The procedure for creating the characteristic diagrams I to III of FIGS. 2 to 4 described above is summarized as follows.
The characteristic diagram I of embrittlement temperature and plasticizer concentration in FIG. 2 is prepared as follows.
(A) The measurement points of the embrittlement temperature and plasticizer concentration of a new hose are plotted on the coordinates of FIG.
(B) The measurement points of the embrittlement temperature and the plasticizer concentration of a test piece cut out from one hose exposed to the environment for a predetermined period are plotted on the coordinates of FIG.
(C) A characteristic diagram I is created by connecting the two plots (a) and (b) with a straight line.
In order to obtain a highly accurate characteristic diagram I, in the procedure (b), the embrittlement temperature and the plasticizer concentration are measured for each of a plurality of hoses exposed to the environment for a plurality of periods, and on the coordinates of FIG. And plot three or more plots to obtain a characteristic diagram.
For example, the characteristic diagram I is updated by obtaining a sample of the hose 1 at regular intervals.

The characteristic diagram II of the plasticizer concentration and usage period in FIG. 3 is prepared as follows.
(A) The measurement point of the plasticizer concentration of a new hose is plotted on the coordinates of FIG.
(B) The measurement points of the plasticizer concentration of a test piece cut out from one hose exposed to the environment for a predetermined period are plotted on the coordinates of FIG.
(C) A characteristic diagram II is created by connecting the two plots (a) and (b) with a straight line.
In order to obtain a highly accurate characteristic diagram II, in the procedure of (b), the plasticizer concentration is measured for each of a plurality of hoses exposed to the environment for a plurality of periods, and plotted on the coordinates of FIG. Three or more plots are connected to form a characteristic diagram.
For example, a sample of the hose 1 is appropriately obtained at regular intervals, and the characteristic diagram II is updated.

The characteristic diagram III of the embrittlement temperature and use period in FIG. 4 is created as follows.
(A) The measurement point of the brittle temperature of a new hose is plotted on the coordinates of FIG.
(B) The measurement points of the embrittlement temperature of a test piece cut out from one hose exposed to the environment for a predetermined period are plotted on the coordinates of FIG.
(C) A characteristic diagram III is created by connecting the two plots (a) and (b) with a straight line.
In order to obtain a characteristic graph III with high accuracy, in the procedure of (b), the embrittlement temperature is measured for each of a plurality of hoses exposed to the environment for a plurality of periods, and plotted on the coordinates of FIG. Three or more plots are connected to form a characteristic diagram.
For example, a sample of the hose 1 is appropriately obtained at regular intervals, and the characteristic diagram III is updated.
In this way, a more accurate maximum usable period Tmax can be obtained.

[E: Method for calculating remaining usable period]
The remaining usable period of the vinyl chloride hose 1 is expressed as Tres, and the usage period of the hose that is a deterioration determination target is expressed as Tuse. The remaining serviceable period Tres is calculated by different methods depending on whether the service period Tuse is clear and whether the hose 1 is available for testing for embrittlement temperature and plasticizer concentration. The calculation flow of the remaining usable period Tres will be described below with reference to FIG.

(Step E1) It is determined whether the period Tuse used by the hose is clear.
If the period Tuse used by the hose 1 is clear, the process proceeds to step E2, and if not clear, the process proceeds to step E3.

<For laid hoses with a clear period of use>
(Step E2) The remaining period obtained by subtracting the already used period Tuse from the aforementioned maximum usable period Tmax, that is, the remaining usable period Tres is calculated as the remaining life.
That is, Tres = Tmax−Tuse.

<In case of laying hose whose period of use is unknown>
(Step E3) It is determined whether the vinyl chloride hose 1 actually used is available. If available, proceed to step E4 to analyze the embrittlement temperature and plasticizer concentration using this hose specimen. If it is difficult to obtain, a hose manufactured at the same time as the actually used hose is used, and the process proceeds to Step E12.

(Step E4) The outermost layer hard vinyl chloride 2 is cut out from the laying hose in use. Further, as shown in FIG. 5, the outermost layer of hard vinyl chloride 2 is divided into two parts: a surface side 6 and an inner side 7 in contact with the soft vinyl chloride 4.

(Step E5) It is determined whether the maximum usable period Tmax of the hose subject to deterioration determination is the maximum usable period Tmax2 obtained from the embrittlement temperature or the maximum usable period Tmax1 obtained from the plasticizer concentration. When it is Tmax2, the process proceeds to Step E6 in order to calculate Tres from the embrittlement temperature. If it is Tmax1, the process proceeds to step E9 to calculate Tres from the plasticizer concentration.

<Calculate remaining service life from embrittlement temperature>
(Step E6) If the maximum usable period Tmax of the hose subject to deterioration determination is the maximum usable period Tmax2 obtained from the embrittlement temperature, the brittleness on the surface side 6 and the inner side 7 of the hard vinyl chloride 2 of the outermost layer. Measure the soaking temperature. However, if the embrittlement temperatures of the front side 6 and the inner side 7 are different, the higher temperature tempC is used.

(Step E7)) The characteristic diagram III described in FIG. 4, that is, the characteristic diagram III showing the relationship between the embrittlement temperature of the hose 1 and the service period, as shown in FIG. 8, the embrittlement temperature tempC obtained above. Is used to estimate the period of use up to the present, that is, the estimated period of use TermD.

(Step E8) The remaining period obtained by subtracting the estimated usable period TermD from the maximum usable period Tmax2 to the present is calculated as the remaining usable period Tres.
That is, Tres = Tmax2-TermD.

<Calculate the remaining usage period from the plasticizer concentration>
(Step E9) When the maximum usable period Tmax of the hose to be deteriorated is the maximum usable period Tmax1 obtained from the plasticizer concentration, the plasticity on the surface side 6 and the inner side 7 of the hard vinyl chloride 2 of the outermost layer. Measure agent concentration. However, when the plasticizer concentrations on the front side 6 and the inner side 7 are different, the lower plasticizer concentration DensE is used.

(Step E10) In the characteristic diagram II described in FIG. 3, that is, the characteristic diagram showing the relationship between the plasticizer concentration of the hose 1 and the use period, the plasticizer concentration DensE obtained above is plotted as shown in FIG. Thus, the usage period TermF up to now is estimated.

(Step E11) The remaining period obtained by subtracting the estimated usable period TermF from the maximum usable period Tmax1 to the present is calculated as the remaining usable period Tres.
That is, Tres = Tmax1-TermF.

<When it is difficult to obtain a laying hose to be judged for deterioration>
(Step E12) In step E3, when the vinyl chloride hose currently used in the plant or facility, that is, the laying hose is not available, the processing after this step is performed.
Here, the embrittlement temperature for calculating the maximum usable period according to the above-described method for calculating the maximum usable period using a new vinyl chloride hose 1 manufactured in the same lot as the laying hose or at the same time. And measure the plasticizer concentration. However, it is desirable to use a new hose 1 stored indoors.
Alternatively, using a dummy hose that has been used or stored in a similar environment for a predetermined period of time, the embrittlement temperature and plasticizer for calculating the maximum usable period according to the above-described method for calculating the maximum usable period Measure the concentration. In this case as well, it is desirable to use a hose produced in the same lot or at the same time as the laying hose.

  According to the calculation method of the maximum usable period described above, the characteristic diagram II described in FIG. 3, that is, the characteristic diagram showing the relationship between the plasticizer concentration of the vinyl chloride hose 1 and the usage period, and the characteristic curve described in FIG. Figure III, that is, a characteristic diagram showing the relationship between the embrittlement temperature of the vinyl chloride hose 1 and the period of use is prepared.

(Step E13) The maximum usable period Tmax2 and the maximum usable period Tmax1 are obtained according to the above-described method for measuring the maximum usable period. By comparing the two, the shorter one is adopted as the maximum usable period Tmax that is actually used for judging the deterioration of the hose 1.

(Step E14) With reference to the characteristic diagram II in FIG. 3 or the characteristic diagram III in FIG. 4, an estimated use period TermG of the laying hose up to the present time is calculated. The remaining period obtained by subtracting the estimated usable period TermG from the maximum usable period Tmax to the present time of the laid hose is calculated as a remaining life that is a usable period thereafter. That is, Tres = Tmax−TermG.

As explained above, according to the deterioration determination method for the vinyl chloride hose according to the first embodiment, the following operational effects can be obtained.
(1) The hose deterioration state is evaluated by two different methods: measurement of embrittlement temperature and measurement of plasticizer concentration, and the shortest maximum usable period is adopted from the maximum usable period calculated based on each. The remaining usable period is calculated by subtracting the usage time up to now. By this method, it can be confirmed that the remaining use period ends at a point before the breakage is surely made so that the hose is not broken due to deterioration.

(2) The embrittlement temperature is measured at a test temperature every 5 ° C., for example, as defined in JIS standard K7216 described above. Therefore, there is a possibility that a slight increase in embrittlement temperature may be overlooked. In addition, when a fracture in which brittle fracture and ductile fracture are mixed, the exact brittle temperature cannot be known.

  On the other hand, the plasticizer has different volatilization rates and moving speeds in the solid depending on the type, and therefore the concentration decreasing rate in the vinyl chloride varies depending on the type of the plasticizer. Therefore, when two or more kinds of plasticizers are mixed, there is a possibility that a specific plasticizer is depleted earlier than other plasticizers. In this case, the approximate straight line obtained from the relationship between the plasticizer concentration and the embrittlement temperature has an inflection point, which may cause an error. Also, the plasticizer concentration varies depending on the sampling location. This is because the volatilization of the plasticizer occurs only on the surface, and the plasticizer inside the vinyl chloride, which is solid, can move from its original location to its surroundings due to infiltration due to the ambient temperature.

  In the first embodiment, there are two methods: a method for calculating the maximum usable period Tmax2 from the relationship between the embrittlement temperature and the use period, and a method for calculating the maximum usable period Tmax1 from the relationship between the plasticizer concentration and the use period. carry out. Further, the maximum usable period Tmax2 and the maximum usable period Tmax1 are compared, and the shorter one is adopted as the maximum usable period Tmax that is actually used for determining the deterioration of the vinyl chloride hose 1. Thereby, the usage period of the vinyl chloride hose 1 can be set to a time point before the hose breakage due to deterioration, that is, a time point that is a predetermined period before the maximum usable period Tmax. Thereby, the damage by deterioration of a hose can be prevented beforehand and unexpected situations, such as a leak, can be avoided.

Note that the vinyl chloride hose deterioration determination method according to the present invention described above is configured such that, for example, the maximum usable period Tmax can be calculated for a hose containing the following plasticizer.
・ Di-2-ethylhexyl phthalate ・ Cibutyl phthalate ・ Diisodecyl phthalate ・ Diisononyl phthalate ・ Diundecyl phthalate ・ Ditridecyl phthalate ・ Di-2-ethylhexyl adipate ・ Diisodecyl adipate ・ Diisononyl adipate ・ Di-2-ethylhexyl azelate ・ Di-2 -Ethylhexyl sebacate -Tri-2-ethylhexyl trimellitate -Triisodecyl trimellitate -Tricresyl phosphate -Trixyl phosphate -Tributyl phosphate

(Second Embodiment)
An apparatus for carrying out the method for determining deterioration of a vinyl chloride hose described in the first embodiment will be described with reference to FIG.

(Overview of deterioration determination device configuration)
The degradation determination device 10 includes an arithmetic device 60 including peripheral devices such as a CPU, a ROM, and a RAM, an external input device 14 for inputting various data to the arithmetic device 60, and an environmental temperature at which a vinyl chloride hose is laid. A temperature sensor 11 that is measured and input to the arithmetic device 60, a display device 12 that displays various information and warnings calculated by the arithmetic device 60, and a warning device 13 that notifies the warning detected by the arithmetic device 60 to the outside by voice or the like. It has.

  The arithmetic device 60 predicts the deterioration of the vinyl chloride hose based on the storage unit 24 that stores data for determining the deterioration of the vinyl chloride hose and the data of the vinyl chloride hose stored in the storage unit 24. A deterioration prediction unit 22, a warning unit 23 that transmits a warning signal to an external warning device 13 based on a determination or prediction result in the deterioration prediction unit 22, and a data input / output unit 25 are provided.

(About data stored in the storage unit 24)
As various data stored in the storage unit 24, for example, the data of the characteristic diagram I (FIG. 2) showing the correlation between the plasticizer concentration and the embrittlement temperature described above is a vinyl chloride hose having a different configuration and a different production time. Are respectively prepared and stored in the hose data section 41. The data representing the characteristic curve II of the time-dependent change in the plasticizer concentration of the vinyl chloride hose (FIG. 3) and the data representing the characteristic curve III of the time-dependent change in the embrittlement temperature (FIG. 4) are similarly different and different. Each is prepared for the vinyl chloride hose at the time of manufacture and stored in the use period data section 42.

  The storage unit 24 also stores a deterioration state threshold value for giving a warning about the deterioration state of the vinyl chloride hose, that is, a remaining usable period threshold value.

  As described above, the storage unit 24 stores, for each hose, data obtained by measurement with a test piece of a hose in use or measurement with a test piece of a hose manufactured at the same time. . These data, which are updated / added by appropriately measuring the test piece, are input from the external input device 14 and stored in the usage period data section 42.

  The hose list unit 43 stores a list of a plurality of vinyl chloride hoses used in plants and equipment to which the deterioration determination device according to the present invention is applied. This list includes the number of each hose, hose type, and use start time, and these information are used for predicting the deterioration state.

  The period of use of each hose up to now can be calculated from the start of use of each hose. Or when this use start time is not clear, as explained above, you may use the use period obtained by the measurement by the test piece of a hose as a use period until the present of a hose.

  Note that the configuration of the storage unit 24 described above is an example, and various forms of storage of various data having the above-described contents are possible. Therefore, the present invention is not limited to the configuration of the storage unit 24 shown in FIG.

(Regarding the configuration and operation of the deterioration prediction unit 22)
The deterioration predicting unit 22 includes a diagram I (FIG. 2) showing a correlation between the plasticizer concentration and the embrittlement temperature, a change characteristic of the plasticizer concentration with time (diagram II of FIG. 3), and a change with time of the embrittlement temperature. Based on the characteristics (diagram III in FIG. 4), the maximum usable period calculation unit 32 that calculates the maximum usable period as described above, and the calculated maximum usable period and stored in the storage unit 24. A remaining usable period calculating unit 33 that calculates a remaining usable period from the use start time of the vinyl chloride hose. Further, the deterioration prediction unit 22 compares the calculated remaining usable period with a predetermined threshold value stored in the warning data unit 44 of the storage unit 24, and determines whether the remaining usable period is smaller than the predetermined threshold value. A determination unit 31 for determination is provided. The determination unit 31 performs such determination for all the vinyl chloride hoses. The maximum usable period and the remaining usable period may differ depending on the environment and usage conditions, and the hose deterioration rate may change, so the maximum usable period and the remaining usable period are stored each time these are calculated. It is added to the data of each hose in the 24 hose list parts 43.

  When there is a vinyl chloride hose whose remaining usable period is smaller than a predetermined threshold, that is, it is determined that the plasticizer concentration or the embrittlement temperature indicating the state of the predetermined vinyl chloride hose is deteriorated, the deterioration prediction unit 22 The determination unit 31 outputs, to the warning unit 23, for example, the numbers of the vinyl chloride hoses that are in a predetermined deterioration state.

  A plurality of threshold values may be provided as the predetermined threshold value of the remaining usable period stored in the warning data unit 44. For example, the warning level is set to 1 when the remaining usable period is 6 months (first threshold). Further, if the remaining usable period is one month (second threshold), the warning level is set to 2. This warning level is set by the determination unit 31 and is output to the warning unit 23 together with the calculated remaining usable period. Further, it is added to the data of each hose in the hose list part of the storage unit 24.

  When the number of the vinyl chloride hose determined to be in the deteriorated state is input from the deterioration predicting unit, the warning unit 23 reads the remaining usable period of the hose with this number from the storage unit 24 and displays the display device such as an external display 12 is displayed. At this time, for example, if the warning level is 1, it is displayed on the display or the like so as to be easily recognized. Further, if the warning level is 2, the warning lamp 13 may be turned on. Note that the threshold values described above are not limited to two, and three or more threshold values may be provided, and different warnings may be issued according to the degree of urgency.

  If necessary, the deterioration state of all the vinyl chloride hoses can be read from the storage unit 24 and displayed. This display may be performed on the display device 12 or may be output to an external computer (not shown) or a plant control device via the data input / output unit 25 and performed on these display devices.

  The external input device 14 may be an external data device or other computer device connected to a network, or may be an input device such as a keyboard.

  Since there are many vinyl chloride hoses used in plants, etc., obtain samples of these vinyl chloride hoses and measure the plasticizer concentration and embrittlement temperature in order to update the data in Figs. For vinyl chloride hoses in use, where the same configuration and the same manufactured vinyl chloride hoses are used, and the data is updated, the maximum use as described above for vinyl chloride hoses in use The possible period and the remaining usable period are calculated.

  According to the vinyl chloride hose degradation determination device of the second embodiment described above, a warning is reliably generated before the vinyl chloride hose deteriorates and becomes damaged. Therefore, it is possible to prevent damage to the hose due to deterioration by replacing the vinyl chloride hose that has been determined to be deteriorated.

(Modification 1)
As can be seen from the above description, in the second embodiment of the present invention, the deterioration state of all the vinyl chloride hoses used in the plant or the like can be predicted or determined. Using this function, it is possible to schedule the replacement work of the vinyl chloride hose.

For example, the data of the vinyl chloride hose in use stored in the hose list unit 43 is displayed on the display device 12 as shown in FIG.
The time when the warning level 1 or 2 described as an example above is displayed can also be predicted using the above-described method for calculating the remaining usable period, and this is also displayed. In this case, the lower limit concentration of different plasticizers and different brittle temperatures are set corresponding to warning level 1 or 2, and based on these, the maximum usable period and the remaining usable period are set as described above. What is necessary is just to calculate.

  In this way, it is possible to set the hose replacement work date (indicated by ▼) with reference to the displayed deterioration prediction of each vinyl chloride hose. The exchange work day of each hose set in this way can also be stored in the hose list part 43 for each hose.

(Modification 2)
(Temperature sensor usage method 1: Considering the decrease in vinyl chloride temperature)
For example, in winter, the outside air temperature is lowered, the temperature of the vinyl chloride hose exposed in the outdoor part of the building is lowered, and the embrittlement temperature calculated above may be approached.

In such a case, the temperature sensor 11 is installed in the vinyl chloride hose itself or in the surrounding environment, and the deterioration is predicted when the difference between the vinyl chloride hose or the ambient temperature and the embrittlement temperature becomes smaller than a predetermined threshold. It may be determined that the vinyl chloride hose is deteriorated by the part.
Alternatively, it is also possible to take in data such as a weather forecast from an external input device and determine the deterioration of the vinyl chloride hose from the predicted outside air temperature.
Even in the deterioration determination in consideration of such temperature, two or more kinds of temperature difference threshold values used for the determination may be prepared and different warnings may be performed. Although the magnitude of the temperature change during the day varies depending on the season, when the remaining usable period described above is reduced to a certain extent, it is desirable to frequently perform deterioration determination in consideration of such temperature in winter.

(Modification 3)
(Temperature sensor utilization method 2: Considering decrease in plasticizer concentration)
For example, in summer, the outside air temperature rises, and the temperature of the vinyl chloride hose exposed outside the building rises. Also, depending on the usage state of the hose, the temperature of the hose rises even when a high-temperature fluid flows. In such a case, it is conceivable that the release of the plasticizer from the hose is accelerated and the plasticizer lower limit concentration described in FIG.

  In such a case, although detailed explanation is omitted, the change characteristic of the plasticizer content depending on the temperature is separately stored in the storage unit, and the change in the plasticizer content due to the temperature is integrated to obtain a vinyl chloride type. When the difference between the plasticizer concentration of the hose and the lower limit concentration of the plasticizer described above becomes smaller than a predetermined threshold, the deterioration prediction unit may determine that the vinyl chloride hose has deteriorated. Even in the deterioration determination in consideration of such temperature, two or more kinds of temperature difference threshold values used for the determination may be prepared and different warnings may be performed.

(Modification 4)
(Other methods of use; deterioration due to ultraviolet rays)
The vinyl chloride hose is deteriorated by irradiation with ultraviolet rays, and the embrittlement temperature rises. Although detailed explanation is omitted, it is also possible to input the UV irradiation amount data to the vinyl chloride hose exposed in the outdoor part of the building from the outside to the deterioration determination device 10 to correct the embrittlement temperature described above. It is. Since such deterioration due to ultraviolet irradiation depends on the cumulative amount of ultraviolet irradiation, data on the relationship between the embrittlement temperature and the ultraviolet ray dose is stored in advance in the storage unit, and meteorological data is obtained from the outside for the irradiation dose. It is possible to evaluate deterioration due to ultraviolet irradiation. When the difference from the minimum environmental temperature described with reference to FIG. 2 becomes smaller than a predetermined threshold, the deterioration predicting unit 22 determines that the deterioration has occurred. Also in this case, as in the third modification, a plurality of threshold values may be provided, and different warnings may be given to each.

The present invention can also be carried out with the following modifications.
(1) Using the characteristic diagram I in FIG. 2 showing the correlation between the plasticizer concentration and the embrittlement temperature and the characteristic diagram II in FIG. May be calculated.
(2) The deterioration judging device of such a modified example is characterized in that the plasticizer concentration of the vinyl chloride hose changes with time (line II in FIG. 3) and the plasticizer concentration DensE of the vinyl chloride hose to be judged (see FIG. 3). 9) and a time-dependent change characteristic with reference to the storage unit 24 (FIG. 7) and the plasticizer concentration DensE (FIG. 9), the obtained use period is the first use period of the vinyl chloride hose to be determined A first usage period calculation unit 22 (FIG. 7) that calculates as TermF (FIG. 9) is provided, and deterioration is determined based on the first usage period.

(3) In the deterioration determination apparatus of the above modification, the storage unit 24 further stores a characteristic diagram (diagram I in FIG. 2) indicating the correlation between the plasticizer concentration of the vinyl chloride hose and the embrittlement temperature. The The lower limit for calculating the plasticizer concentration corresponding to the embrittlement temperature as the lower limit concentration with reference to the characteristic diagram by the embrittlement temperature equal to the minimum temperature under the environment where the vinyl chloride hose to be judged is used. With reference to the concentration calculation unit 22 (see FIGS. 2 and 7) and the time-dependent change characteristic of the plasticizer concentration by the lower limit concentration (diagram II in FIG. 3), the obtained usage period is set to the first of the vinyl chloride hose. The difference between the first maximum usable period Tmax1 calculated as the maximum usable period Tmax1 (FIG. 7) and the first maximum usable period Tmax1 and the first usable period TermF (FIG. 9) is the remaining usable period Tres. And a remaining life calculation unit 33 (FIG. 7).

(4) The deterioration judging method of the modified example is a method for judging the deterioration of a vinyl chloride hose that has been used for an arbitrary period. The plasticizer concentration of the vinyl hose is detected, the time-dependent change characteristic is referred to based on the detected plasticizer concentration, and the obtained use period is calculated as the first use period of the vinyl chloride hose to be determined. Deterioration is determined by the period of use.
(5) The deterioration judging method of the above modification further calculates a characteristic diagram showing the correlation between the plasticizer concentration of the vinyl chloride hose and the embrittlement temperature, and is used in an environment where the vinyl chloride hose to be judged is used. Obtained by referring to the characteristic diagram with the embrittlement temperature equal to the minimum temperature at, calculating the plasticizer concentration corresponding to the embrittlement temperature as the lower limit concentration, and referring to the time-dependent characteristics of the plasticizer concentration with the lower limit concentration. The usage period is calculated as the first maximum usable period of the vinyl chloride hose, and the difference between the first maximum usable period and the first usage period is calculated as the remaining usable period.

The effect of this modification is as follows.
The embrittlement temperature is measured at a test temperature every 5 ° C., for example, as defined in the above-mentioned JIS standard K7216. Therefore, there is a possibility that a slight increase in the embrittlement temperature may be overlooked. The calculation accuracy of the usable period may be reduced. In this respect, since the plasticizer concentration can be measured as a continuous value, the remaining usable period can be accurately calculated.

  In addition, this invention is not limited to said embodiment and modification. A person skilled in the art combines the various methods and apparatus with the vinyl chloride hose degradation determination method or degradation determination apparatus according to the present invention described in the above-described embodiments and modified examples, thereby providing a higher safety apparatus and It can be a device.

DESCRIPTION OF SYMBOLS 1 ... Vinyl chloride type hose 2 ... Hard vinyl chloride 3 ... Rubber 4 ... Soft vinyl chloride 5 ... Cut surface 6 ... Vinyl chloride surface side 7 ... Vinyl chloride inside 10 ... Degradation judgment device 11 ... Temperature sensor 12 ... Display device 13 ... Warning Device 14 ... External input device 21 ... Temperature detection unit 22 ... Deterioration prediction unit 23 ... Warning unit 24 ... Storage unit 25 ... Data input / output unit 31 ... Judgment unit 32 ... Maximum usable period calculation unit 33 ... Remaining usable period calculation unit 41 ... Hose data part 42 ... Usage period data part 43 ... Hose list part 44 ... Warning data part 60 ... Arithmetic unit

Claims (11)

In a device that determines the deterioration of a vinyl chloride hose that has been in use for any period of time,
A storage unit for storing a time-dependent change characteristic of a plasticizer concentration of a vinyl chloride hose and a plasticizer concentration of a vinyl chloride hose to be determined;
A first use period calculation unit that refers to the time-dependent change characteristic according to the plasticizer concentration and calculates the obtained use period as a first use period of the vinyl chloride hose to be determined;
A deterioration determining apparatus, wherein deterioration is determined based on the first period of use. In the deterioration determination apparatus according to claim 1,
In the storage unit, a characteristic diagram showing a correlation between the plasticizer concentration of the vinyl chloride hose and the embrittlement temperature is stored,
Refer to the characteristic diagram based on the embrittlement temperature equal to the minimum temperature under the environment where the vinyl chloride hose to be judged is used, and calculate the plasticizer concentration corresponding to the embrittlement temperature as the lower limit concentration. A calculation unit;
A first maximum use period calculation unit that refers to the time-dependent change characteristic of the plasticizer concentration by the lower limit concentration and calculates the obtained use period as a first maximum usable period of the vinyl chloride hose;
A deterioration determination apparatus, further comprising: a remaining life calculating unit that calculates a difference between the first maximum usable period and the first usable period as a remaining usable period. In the deterioration determination apparatus according to claim 2,
In the storage unit, the temporal change characteristic of the embrittlement temperature of the vinyl chloride hose and the embrittlement temperature of the vinyl chloride hose to be judged are stored,
A second usage period calculation unit that refers to the time-varying characteristics according to the embrittlement temperature and calculates the obtained usage period as a second usage period of the vinyl chloride hose to be determined;
The time-dependent change characteristic of the embrittlement temperature is referred to by the embrittlement temperature equal to the minimum temperature under the environment where the vinyl chloride hose to be judged is used, and the obtained use period is set as the second maximum usable period. A second maximum usable period calculating unit for calculating;
The first maximum usable period of the vinyl chloride hose calculated based on the plasticizer concentration and the shortest period of the second maximum usable period of the vinyl chloride hose calculated based on the brittle temperature A specific part that identifies the possible period, and
When the specified maximum usable period is the first maximum usable period, the remaining life calculating unit calculates a difference between the first maximum usable period and the first usable period as the remaining usable period. When the specified maximum usable period is the second maximum usable period, the difference between the second maximum usable period and the second usable period is calculated as the remaining usable period. A deterioration determination device characterized by: In the deterioration determination apparatus according to claim 2 or 3,
A deterioration determination apparatus comprising: a warning unit that notifies a warning when the remaining usable period is shorter than a predetermined threshold value. In the method of judging deterioration of a vinyl chloride hose that has been used for an arbitrary period,
Calculate the time-dependent characteristics of the plasticizer concentration of the vinyl chloride hose,
Detect the plasticizer concentration of the vinyl chloride hose to be judged,
With reference to the time-dependent change characteristic by the detected plasticizer concentration, the obtained use period is calculated as the first use period of the vinyl chloride hose to be determined,
A deterioration determination method, wherein deterioration is determined based on the first use period. In the deterioration determination method of claim 5,
Calculate a characteristic diagram showing the correlation between the plasticizer concentration of the vinyl chloride hose and the embrittlement temperature,
Refer to the characteristic diagram by the embrittlement temperature equal to the minimum temperature under the environment where the vinyl chloride hose to be judged is used, and calculate the plasticizer concentration corresponding to the embrittlement temperature as the lower limit concentration,
With reference to the time-dependent change characteristic of the plasticizer concentration by the lower limit concentration, the obtained use period is calculated as the first maximum usable period of the vinyl chloride hose,
A deterioration determination method, wherein a difference between the first maximum usable period and the first usable period is calculated as a remaining usable period. In the deterioration determination method of claim 6,
Calculate the aging characteristics of the embrittlement temperature of vinyl chloride hoses,
Detect the brittle temperature of the vinyl chloride hose to be judged,
With reference to the time-dependent change characteristic according to the detected embrittlement temperature, the obtained use period is set as the second use period of the vinyl chloride hose to be determined,
The time-dependent change characteristic of the embrittlement temperature is referred to by the embrittlement temperature equal to the minimum temperature under the environment where the vinyl chloride hose to be judged is used, and the obtained use period is set as the second maximum usable period. Calculate
The first maximum usable period of the vinyl chloride hose calculated based on the plasticizer concentration and the shortest period of the second maximum usable period of the vinyl chloride hose calculated based on the brittle temperature Identified as possible period,
When the specified maximum usable period is the first maximum usable period, the difference between the first maximum usable period and the first usable period is calculated as a remaining usable period, and the specified When the determined maximum usable period is the second maximum usable period, the difference between the second maximum usable period and the second usable period is calculated as a remaining usable period. Judgment method. In the deterioration determination method according to claim 6 or 7,
A deterioration determination method, wherein a warning is notified when the remaining usable period is shorter than a predetermined threshold. In the deterioration determination method of claim 5,
For the hose subject to deterioration determination, the first plasticizer concentration of the new hose and the second plasticizer concentration of the hose exposed to the environment for a predetermined period of time are detected.
A deterioration determination method characterized in that the time-dependent change characteristic of the plasticizer concentration is created by connecting the intersection of the first plasticizer concentration and zero elapsed time and the intersection of the second plasticizer concentration and a predetermined time. In the deterioration determination method of claim 6,
For the hose subject to deterioration determination, the first plasticizer concentration and the first embrittlement temperature of the new hose, and the second plasticizer concentration and the second embrittlement temperature of the hose exposed to the environment for a predetermined period of time are detected.
A characteristic diagram showing the correlation between the plasticizer concentration and the embrittlement temperature is created by connecting the intersection between the first plasticizer concentration and the first embrittlement temperature and the intersection between the second plasticizer concentration and the second embrittlement temperature. A deterioration determination method characterized by: In the deterioration determination method of claim 7,
For the hose subject to deterioration determination, the first embrittlement temperature of the new hose and the second embrittlement temperature of the hose exposed to the environment for a predetermined period are detected.
A deterioration determination method, characterized in that the time-dependent change characteristic of the embrittlement temperature is created by connecting the intersection of the first embrittlement temperature and the elapsed time zero and the intersection of the second embrittlement temperature and a predetermined time.

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