CN115479153A

CN115479153A - Valve maintenance support device and method

Info

Publication number: CN115479153A
Application number: CN202210570469.3A
Authority: CN
Inventors: 田中雅人; 山崎史明; 吉田靖弘
Original assignee: Azbil Corp
Current assignee: Azbil Corp
Priority date: 2021-05-31
Filing date: 2022-05-24
Publication date: 2022-12-16
Also published as: JP2022183665A; KR20220162066A

Abstract

The valve maintenance auxiliary device and the method improve the working efficiency of valve maintenance. The valve maintenance support device of the present invention includes: a fully-open data extraction unit (5) that searches for data that indicates an opening command value that indicates full-opening, from among the opening command values that are assigned to the bellows valves, and extracts, as diagnostic data, the actual opening value of the bellows valve to which the opening command value is assigned and the actual opening value that is a time period corresponding to the opening command value that indicates full-opening; a full-open failure determination unit (6) that determines, based on the diagnostic data, whether or not a full-open failure state in which the bellows valve to which the opening degree command value that instructs full-open has not become fully open has occurred; and a determination result presentation unit (8) that presents the ID of the bellows valve determined to have occurred in the fully-open/fully-closed state as the ID of the valve in which the bellows has been broken.

Description

Valve maintenance support device and method

Technical Field

The present invention relates to a technique for assisting maintenance work, and more particularly, to a valve maintenance assisting device and method for assisting maintenance work of a bellows valve including a bellows having a corrugated shape provided so as to surround an outer periphery of a valve shaft coupled to a valve body.

Background

Conventionally, valves (for example, control valves shown in fig. 10) used in petrochemical plants and the like require special attention to safety, and therefore require regular maintenance. The valve 100 shown in fig. 10 includes a valve main body 101, a positioner 102, and an operator 103. The actuator 103 moves the valve shaft (valve stem) 104 up and down according to the air pressure Po supplied from the positioner 102, and adjusts the opening degree of the valve (gap between the valve body 105 and the seat ring 106). I.e. to regulate the flow of fluid.

The positioner 102 detects the lift position of the valve shaft 104, that is, the actual opening degree of the valve, based on the rotational angle position of the feedback lever 107 coupled to the valve shaft 104, and supplies the air pressure Po corresponding to the difference between the detected actual opening degree and the set opening degree to the operator 103.

In this valve 100, a corrugated bellows (bellows seal) 108 is provided on the outer periphery of a valve shaft 104 coupled to a valve body 105 in order to prevent external leakage of fluid. The bellows 108 is made of a corrosion-resistant metal material, and is provided in a lower flange 109 coupled to the valve main body 101 so as to surround the outer periphery of the valve shaft 104.

The bellows 108 is supported in the lower flange 109 between a bellows ring 111 and a bellows flange 112, the bellows ring 111 being fitted to the valve shaft 104, and the bellows flange 112 being sandwiched between the lower flange 109 and the upper flange 110. In the upper flange 110, a gland packing 113 is provided between the outer peripheral surface of the valve shaft 104 and the inner peripheral surface of the upper flange 110 in order to further prevent external leakage of the fluid. The lower portion of the upper flange 110 serves as an upper cover with respect to the lower flange 109.

The valve 100 provided with such a corrugated bellows 108 is called a bellows valve. In a factory or the like where these valves are installed, it is necessary to efficiently maintain a plurality of valves, and in order to improve the maintenance work efficiency, a method of detecting breakage of a bellows valve has been proposed (see patent document 1).

The valve maintenance support device disclosed in patent document 1 presents information on the maximum frictional force of the bellows valve to an operator as a diagnostic index, and thereby estimates whether the bellows valve is suspected of being broken.

However, even if the bellows 108 is broken, the effect of the breakage may not appear in the detection result of the frictional force. The leakage of the fluid from the bellows 108 is a significant event, but in the technique disclosed in the reference 1, there is a possibility that the breakage of the bellows 108 cannot be detected.

A plurality of valves are used in petrochemical plants and the like. For example, in the example of FIG. 11, the valves 100-A and 1000-M are disposed in the flow path 114-1, and the valve 100-C is disposed in the flow path 114-3. 115-A, 115-C, 115-M are flow meters, 116 is a tank, and 117 is a pressure transmitter. In this way, further improvement in efficiency of maintenance work is required in equipment using a plurality of valves and the like.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2019-087003

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-described problems, and an object thereof is to provide a valve maintenance assisting device and a method that can improve the work efficiency of maintenance of a bellows valve.

Means for solving the problems

The valve maintenance support device according to the present invention is characterized by comprising: an opening command value storage unit configured to store data of an opening command value given to the bellows valve in association with an ID of the bellows valve that is a transmission source of the data; an opening measurement value storage unit configured to store data of an actual opening value of the bellows valve in association with an ID of the bellows valve that is a transmission source of the data; a fully-open data extraction unit configured to search for data of an opening degree command value indicating full-open among the opening degree command values stored in the opening degree command value storage unit, and extract, as diagnostic data, an actual opening value of the bellows valve to which the opening degree command value is given, the actual opening value being a time zone corresponding to the opening degree command value indicating full-open; a full-open failure determination unit configured to determine, based on the diagnostic data, whether or not a full-open failure state in which the bellows valve to which an opening degree command value for instructing full-open is applied is not fully open has occurred; and a determination result presentation unit configured to present the ID of the bellows valve determined to be in the fully-opened/fully-closed state as the ID of the valve in which the bellows is broken.

In addition, in the valve maintenance support device 1 according to the present invention, the device further includes a bellows damage determination unit configured to determine that a bellows damage has occurred to the bellows valve when the same bellows valve is in the fully open/closed state a plurality of times and the degree of opening insufficiency per one of the plurality of times of the fully open/closed state monotonically increases, and the determination result presentation unit presents the ID of the bellows valve determined by the bellows damage determination unit to have the bellows damage instead of presenting the ID of the bellows valve determined by the fully open/closed determination unit to have the fully open/closed state.

In the valve maintenance support device 1 according to the present invention, the bellows damage determination unit determines that the bellows valve is damaged when the degree of opening insufficiency of the same bellows valve monotonically increases at a substantially constant slope.

The valve maintenance support method according to the present invention includes a step 1 of storing data of an opening degree command value given to a bellows valve in association with an ID of the bellows valve that is a transmission source of the data; a step 2 of storing data of an actual opening value of the bellows valve in association with an ID of the bellows valve which is a transmission source of the data; a 3 rd step of searching for data indicating an opening command value of full opening among the opening command values stored in the 1 st step, and extracting an actual opening value of the bellows valve to which the opening command value is given and an actual opening value of a time zone corresponding to the opening command value indicating full opening as diagnostic data; a 4 th step of determining whether or not a fully-opened incomplete state in which the bellows valve to which an opening degree command value for instructing full opening is given is not fully opened occurs, based on the diagnostic data; and a 5 th step of presenting the ID of the bellows valve determined to be in the fully open/fully closed state as the ID of the valve in which the bellows is broken.

In addition, in the configuration example 1 of the valve maintenance support method according to the present invention, the method further includes a step 6 of determining that the bellows valve is damaged when the same bellows valve is in the fully open state a plurality of times and the degree of opening insufficiency per one of the plurality of times of the fully open state monotonously increases, and the step 5 further includes: instead of presenting the ID of the bellows valve determined in the 4 th step as the fully-opened/incompletely-opened state, the ID of the bellows valve determined in the 6 th step as the bellows breakage is presented.

In addition, in a configuration example 1 of the valve maintenance support method according to the present invention, the 6 th step includes the steps of: when the degree of insufficiency of the opening of the same bellows valve monotonously increases with a substantially constant slope, it is determined that the bellows valve has a bellows damage.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, by monitoring the full open abnormality of the bellows valve, it is possible to detect the leakage of the fluid from the bellows and to assist the job in which the job master selects the bellows valve to be a maintenance candidate. As a result, in the present invention, the work efficiency of maintenance of the bellows valve can be improved.

Drawings

Fig. 1 is a block diagram showing a configuration of a valve maintenance support device according to embodiment 1 of the present invention.

Fig. 2 is a flowchart illustrating the operation of the valve maintenance support device according to embodiment 1 of the present invention.

Fig. 3 is a flowchart illustrating the operation of the valve maintenance support device according to embodiment 1 of the present invention.

Fig. 4 shows an example 1 of the opening operation of the bellows valve.

Fig. 5 is a diagram showing an example in which the degree of opening insufficiency monotonically increases at a substantially constant slope.

Fig. 6 is a diagram showing an example in which the degree of opening insufficiency does not monotonically increase.

Fig. 7 is a diagram showing an example in which the degree of opening insufficiency increases, but the slope is not substantially constant.

Fig. 8 is a diagram showing a plant and a facility management system thereof according to embodiment 2 of the present invention.

Fig. 9 is a block diagram showing an example of a configuration of a computer for realizing the valve maintenance support device according to embodiment 1 and embodiment 2 of the present invention.

Fig. 10 is a view showing an example 1 of the control valve.

Fig. 11 is a diagram showing an example of a plurality of valves used for tanks in a plant.

Detailed Description

[ principles of the invention ]

The inventors found that even if the bellows valve is broken to such an extent that the influence of the breakage is unlikely to occur in the frictional force detection, there is a breakage accompanying the leakage of the fluid from the bellows (108 in fig. 10) in a case where the breakage is a serious event of the fluid leakage. When the bellows is broken, the fluid flowing through the valve enters the inside of the bellows from the outside of the bellows. Further, in the bellows, expansion and contraction of the bellows in the bellows shape accompanying the vertical movement of the valve shaft (104 in fig. 10) may act as a propulsive force of the fluid, and the fluid may enter the upper cover (the lower portion of the upper flange 110 in fig. 10) in the vicinity of the bellows joint. Since it is not originally assumed that the upper cover is in contact with the fluid, the leakage of the fluid from the bellows can be detected by monitoring the full-open abnormality of the valve due to the intrusion of the fluid.

In addition, when fluid invades into the upper cover, the invaded fluid does not disappear once. Therefore, if the degree of the inability to fully open increases monotonously at a certain rate to some extent, the possibility of fluid leakage is particularly high. That is, if the full-open abnormality is rapidly and naturally eliminated after the full-open abnormality of the valve occurs, it is considered appropriate that the cause thereof is adhesion of temporary scale (for example, carbon-based substances contained in the fluid flowing through the valve) at a position away from the bellows.

[ 1 st embodiment ]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing a configuration of a valve maintenance support device according to embodiment 1 of the present invention. In the following embodiments, for the sake of simplifying the description, it is assumed that the case of the ID (identification information) of the valve and the like are simpler than those used in an actual plant.

The valve maintenance support device is provided with: a valve ID storage unit 1 that stores in advance IDs of a plurality of bellows valves that can be candidates for maintenance; an opening degree acquiring unit 2 that acquires an opening degree command value given to the bellows valve and an actual opening degree value of the bellows valve; an opening command value storage unit 3 that stores data of an opening command value in association with an ID of a bellows valve that is a transmission source of the data; an opening degree measurement value storage unit 4 that stores data of an actual opening degree value in association with an ID of a bellows valve that is a transmission source of the data; a fully open data extraction unit 5 that searches for data of an opening degree command value indicating full opening among the opening degree command values stored in the opening degree command value storage unit 3, and extracts, as diagnostic data, an actual opening degree value of the bellows valve to which the opening degree command value is given, the actual opening degree value being a time period corresponding to the opening degree command value indicating full opening; a full-open failure determination unit 6 that determines, based on the diagnostic data, whether or not a full-open failure state in which the bellows valve to which an opening degree command value for instructing full-open is applied is not fully open has occurred; a bellows damage determination unit 7 that determines that a bellows damage has occurred to the bellows valve when the same bellows valve has occurred in a plurality of fully-open-incomplete states and the degree of insufficiency of the opening per one of the plurality of fully-open-incomplete states has monotonically increased; and a determination result presentation unit 8 that presents (displays) the ID of the bellows valve determined as the bellows damage.

Fig. 2 and 3 are flowcharts illustrating the operation of the valve maintenance support device according to the present embodiment. In the present embodiment, for example, 26 valves are provided in the device, and these 26 valves are respectively assigned inherent IDs "a", "B", "C", "8230", "M", "8230", "X", "Y" and "Z" in advance. In particular, the valves having the valve IDs "a", "C", and "M" are bellows valves provided with bellows, and the IDs "a", "C", and "M" are stored in the valve ID storage unit 1 in advance.

The positioner (102 in fig. 10) used in each bellows valve supplies an air pressure corresponding to a difference between an opening degree command value SP (valve stem position command value) given from a higher-level device and an actual opening degree value PV (valve stem position measurement value) of the bellows valve to an operator (103 in fig. 10).

For the bellows valves having valve IDs registered in the valve ID storage section 1, the opening degree acquisition section 2 acquires data of the opening degree command value SP and the actual opening degree value PV from the positioner of each of the bellows valves (step S100 in fig. 2).

The opening degree obtaining unit 2 stores data of the opening degree command value SP, an ID of a bellows valve as a transmission source of the data, and information of a reception time of the data in association with each other in the opening degree command value storage unit 3 (step S101 in fig. 2). The opening degree acquiring unit 2 stores the data of the actual opening degree value PV, the ID of the bellows valve that is the transmission source of the data, and the information of the reception time of the data in association with each other in the opening degree measurement value storage unit 4 (step S102 in fig. 2).

The ID of the bellows valve may be obtained by the opening degree obtaining section 2 as long as the valve ID is transmitted by adding the positioner of the bellows valve to the data of the opening degree command value SP and the actual opening degree value PV. The time information may be added to the positioner side of the bellows valve or may be added by the opening degree acquiring unit 2.

By repeating the processing in steps S100 to S102 in this way, the time-series data of the opening degree command value SP and the actual opening degree value PV are stored in the opening degree command value storage unit 3 and the opening degree measurement value storage unit 4.

Next, the full-open data extraction unit 5 searches for data of the opening degree command value SP instructing full opening, among the opening degree command values SP stored in the opening degree command value storage unit 3 (step S103 in fig. 3). Then, the fully-open data extraction unit 5 extracts, as diagnostic data, the actual opening value PV of the bellows valve (the same ID bellows valve) to which the opening degree command value SP that instructs fully-opening is given and which is the time zone corresponding to the opening degree command value SP that instructs fully-opening, from among the actual opening values PV stored in the opening degree measured value storage unit 4 (step S104 in fig. 3).

The actual opening value PV of the time zone corresponding to the opening command value SP that instructs full opening is the actual opening value PV from the same time as the opening command value SP that instructs full opening to the time when the predetermined time Top has elapsed. The bellows valve has a response delay with respect to the opening degree command value SP. Therefore, for example, a time longer than a time required for the normal bellows valve to open 0% → 100% may be set as the predetermined time Top. In the case of a normal bellows valve, the valve is fully opened for a predetermined time Top from the time when the opening degree command value SP for instructing full opening is given.

The all-open-failure determining unit 6 determines whether or not the bellows valve to which the opening degree command value SP that instructs the all-open state is applied is in the all-open-failure state in which the bellows valve is not fully open, based on the diagnostic data extracted for the opening degree command value SP that instructs the all-open state (step S105 in fig. 3).

Fig. 4 (a) and 4 (B) show an example 1 of the opening operation of the bellows valve. In the example of fig. 4 (a), the actual opening PV of the bellows valve to which the opening command value SP indicating full opening is given becomes 100% for the predetermined time Top. In this case, the all-open-failure determining unit 6 determines that the bellows valve is not in the all-open-failure state. .

On the other hand, in the example of fig. 4 (B), the actual opening value PV of the bellows valve does not reach 100% within the prescribed time Top. In this case, the all-open-insufficiency determination unit 6 determines that the bellows valve is in the all-open-insufficiency state.

When it is determined that the bellows valve is in the fully open-and-incomplete state and the same bellows valve is in the fully open-and-incomplete state a plurality of times (yes in step S106 in fig. 3), the bellows damage determination unit 7 determines whether the degree of opening deficiency Dif per each of the plurality of fully open-and-incomplete states is monotonically increased.

As shown in fig. 4B, the insufficient opening degree Dif is a difference between the opening degree command value SP indicating full opening (100%) and the maximum value of the corresponding actual opening degree value PV. The state in which the bellows valve is not fully opened in the 1-time opening operation is calculated as the 1-time fully-opened incomplete state, where the state is calculated as the 1-time fully-opened operation from the instruction of the opening degree command value SP to the value other than fully opened. The degree of insufficiency Dif can be obtained in each determination process by the full-opening insufficiency determination unit 6.

When the degree of insufficiency Dif in the multiple fully-open-incomplete states of the same bellows valve monotonically increases (yes in step S107), the bellows damage determination unit 7 determines that the bellows valve is damaged (step S108 in fig. 3). At this time, when the degree of insufficiency Dif of the opening of the same bellows valve monotonically increases at a substantially constant slope, the bellows damage determination unit 7 determines that the bellows is damaged, and excludes a case where the slope is not substantially constant.

For example, fig. 5 shows a case where the degree of opening insufficiency Dif monotonically increases at a substantially constant slope. On the other hand, fig. 6 shows a case where the opening degree deficiency Dif is not monotonously increased, and fig. 7 shows a case where the gradient is not substantially constant but the opening degree deficiency Dif is increased.

The degree of opening insufficiency Dif can be appropriately set by a method of determining whether the degree of opening insufficiency Dif monotonically increases at a substantially constant slope. For example, the bellows damage determination unit 7 determines the coefficient R if the change of the insufficient degree of opening Dif is linearly approximated by the least square method ² (0≦R ² ≦ 1) is a predetermined value TH (TH is 0)<A real number of TH ≦ 1) is equal to or larger than 1, it is determined that the degree of openness deficiency Dif monotonically increases with a substantially constant slope. This method is 1 example, and it is needless to say that the determination may be performed by another determination method. The reason why the degree of openness deficiency Dif monotonically increases at a substantially constant slope is a phenomenon in which the fluid gradually enters the upper cover with the viscous resistance of the fluid. However, as in the case of fig. 7, it is preferable to capture an abnormality (adhesion of scale that does not peel off, etc.) different from the damage of the bellows.

In the present embodiment, it is determined whether or not the degree of opening insufficiency Dif monotonically increases when the same bellows valve has occurred in the fully-opened state a plurality of times, but the plurality of times may be, for example, n times (n is an integer of 3 or more) or more.

The determination result presentation unit 8 presents the valve ID of the bellows valve determined to be broken among the bellows valves having valve IDs registered in the valve ID storage unit 1 to the worker (step S109 in fig. 3).

However, the determination result presentation unit 8 may present (display) information on any one of "damaged" and "undamaged" to all bellows valves having valve IDs registered in the valve ID storage unit 1. In this case, the job person (operator) can confirm the valve ID even if the bellows valve is not broken as a result of the determination that the bellows is broken.

In this way, the processing of steps S100 to S109 in fig. 3 is periodically performed. In the flowchart of fig. 3, it is determined that the bellows valve that monotonically increases with a substantially constant slope at the degree of opening deficiency Dif has a bellows damage, but the process of the bellows damage determination unit 7 (steps S106 to S108) may be omitted. In this case, the determination result presentation unit 8 may present (display) the valve ID of the bellows valve determined by the full-opening insufficiency determination unit 6 as the full-opening insufficiency state as the ID of the valve with the damaged bellows.

In the present embodiment, by monitoring the fully open state of the bellows valve, it is possible to detect the leakage of the fluid from the bellows and to assist the job in which the job master selects the bellows valve to be a maintenance candidate.

[ example 2 ]

Next, embodiment 2 of the present invention is explained. This embodiment is an example of installation for explaining embodiment 1. Fig. 8 is a diagram showing the configuration of a plant and its facility management system, and the same components as those in fig. 11 are denoted by the same reference numerals.

In an equipment management system for an oil and chemical plant, a management apparatus 10 is provided for controlling and managing each equipment of the plant. The valve ID storage unit 1, the opening degree acquiring unit 2, the opening degree command value storage unit 3, and the opening degree measured value storage unit 4 described in embodiment 1 are preferably mounted on the management device 10 because they deal with enormous information unique to a plant.

On the other hand, the all-open data extracting unit 5, the all-open failure determining unit 6, the bellows damage determining unit 7, and the determination result presenting unit 8 basically provide only necessary processing when determining whether or not maintenance of the valve is necessary. In addition, a maintenance executor (job master for maintaining a trusted enterprise) generally receives a request from the enterprise of the plant owner to perform maintenance of the plant. Therefore, assuming that a plurality of unspecified devices are targeted, it is preferable to install the fully open data extraction unit 5, the fully incomplete opening determination unit 6, the bellows damage determination unit 7, and the determination result presentation unit 8 in the portable computer 11 which is carried around by a job person (operator) who is a person in charge of maintenance of entrusted businesses.

The plant management apparatus 10 and the computer 11 are temporarily connected by a communication function such as ethernet (registered trademark) when the maintenance work is performed.

When the operator starts application software on the computer 11, a CPU (Central Processing Unit) of the computer 11 executes Processing according to a program stored in a memory, and realizes functions as the all-open data extracting Unit 5, the all-open failure determining Unit 6, the bellows damage determining Unit 7, and the determination result presenting Unit 8.

The determination result presentation unit 8 reads the valve ID from the valve ID storage unit 1 on the management device 10, reads the determination result of the bellows damage determination unit 7 (or the all-open-failure determination unit 6), and displays the ID of the bellows valve determined as the bellows damage on the display of the computer 11 (step S109 in fig. 3).

The operator confirms the bellows valve that should be paid special attention to the inspection of the bellows based on the displayed valve ID. After confirming the displayed items, the operator releases the connection between the computer 11 and the management apparatus 10.

Thus, the valve maintenance assisting device described in embodiment 1 can be applied to an actual plant.

The valve maintenance support device described in embodiments 1 and 2 is composed of a computer having a CPU, a storage device, and an interface; and a program controlling these hardware resources. Fig. 9 shows a configuration example of the computer. The computer includes a CPU300, a storage device 301, and an interface device (I/F) 302. The I/F302 is connected to, for example, a valve, a management device, a display, and the like. In such a computer, a program for implementing the valve maintenance assistance method of the present invention is stored in the storage device 301. The CPU300 executes the processing explained in embodiment 1 and embodiment 2 according to the program stored in the storage device 301.

In addition, as shown in embodiment 2, when the valve maintenance support device is installed by being divided into the management device 10 and the computer 11, these devices can be realized by a configuration as shown in fig. 9.

[ Industrial Applicability ]

The present invention can be applied to a technique for assisting the valve maintenance operation.

Description of the symbols

1 \8230, a valve ID storage section, 2 \8230, an opening degree acquisition section, 3 \8230, an opening degree instruction value storage section, 4 \8230, an opening degree measured value storage section, 5 \8230, a full opening data extraction section, 6 \8230, a full opening failure determination section, 7 \8230, a bellows damage determination section, 8 \8230, a determination result prompt section, 10 \8230, a management device, 11 \8230anda computer.

Claims

1. A valve maintenance support device is characterized by comprising:

an opening command value storage unit configured to store data of an opening command value given to the bellows valve in association with an ID of the bellows valve that is a transmission source of the data;

an opening degree measurement value storage unit configured to store data of an actual opening degree value of the bellows valve in association with an ID of the bellows valve that is a transmission source of the data;

a full-open data extraction unit configured to search for data of an opening degree command value indicating full-open among the opening degree command values stored in the opening degree command value storage unit, and extract, as diagnostic data, an actual opening value of the bellows valve to which the opening degree command value is given, the actual opening value being a time zone corresponding to the opening degree command value indicating full-open;

a full-open failure determination unit configured to determine, based on the diagnostic data, whether or not a full-open failure state in which the bellows valve to which an opening degree command value instructing full-open has not become fully-open has occurred; and

and a determination result presentation unit configured to present the ID of the bellows valve determined to be in the fully-open/fully-closed state as the ID of the valve in which the bellows is broken.

2. The valve maintenance aid of claim 1,

the device further comprises a bellows damage determination unit configured to determine that a bellows damage has occurred to the bellows valve when the same bellows valve is in a multiple fully-open-incomplete state and the degree of opening insufficiency per multiple fully-open-incomplete states monotonically increases,

the determination result presentation unit presents the ID of the bellows valve determined by the bellows damage determination unit to have the bellows damage instead of the ID of the bellows valve determined by the all-open-incomplete determination unit to have the all-open-incomplete state.

3. The valve maintenance assistance apparatus of claim 2,

the bellows damage determination unit determines that a bellows damage has occurred to the bellows valve when the degree of insufficiency of the opening degree of the same bellows valve monotonically increases at a substantially constant slope.

4. A valve maintenance assistance method, comprising:

a step 1 of storing data of an opening degree command value given to a bellows valve in association with an ID of the bellows valve which is a transmission source of the data;

a step 2 of storing data of an actual opening value of the bellows valve in association with an ID of the bellows valve as a transmission source of the data;

a 3 rd step of searching for data of an opening degree command value indicating full opening among the opening degree command values stored in the 1 st step, and extracting, as diagnostic data, an actual opening degree value of the bellows valve to which the opening degree command value is given and an actual opening degree value of a time zone corresponding to the opening degree command value indicating full opening;

a 4 th step of determining whether or not a fully-opened incomplete state in which the bellows valve to which an opening degree command value for instructing full opening is given is not fully opened occurs, based on the diagnostic data; and

and step 5, presenting the ID of the bellows valve which is judged to be in the fully-opened state as the ID of the valve with the damaged bellows.

5. The valve maintenance assistance method according to claim 4,

further comprising a step 6 of determining that the bellows valve is damaged when the same bellows valve is in a fully-opened state a plurality of times and the degree of opening insufficiency per fully-opened state of the plurality of times monotonically increases,

the step 5 further includes the steps of: the ID of the bellows valve determined in the 6 th step as having the bellows breakage is presented instead of the ID of the bellows valve determined in the 4 th step as having the fully-opened-and-incompletely-opened state.

6. The valve maintenance assistance method according to claim 5,

the 6 th step further comprises the steps of: when the degree of insufficiency of the opening of the same bellows valve monotonously increases at a substantially constant slope, it is determined that the bellows valve is damaged.