JP7628891B2 - Valve maintenance support device and method - Google Patents

Description

The present invention relates to technology for assisting in maintenance work, and in particular to a valve maintenance assistance device and method for assisting in maintenance work for a bellows valve that has a bellows-like bellows that is arranged to surround the outer periphery of a valve stem that is connected to a valve body.

Conventionally, valves used in petrochemical plants and the like (for example, the control valve in FIG. 10) require particular attention to safety, and therefore undergo regular maintenance. The valve 100 shown in FIG. 10 comprises a valve body 101, a positioner 102, and an actuator 103. The actuator 103 moves the valve stem 104 up and down in response to the air pressure Po supplied from the positioner 102, thereby adjusting the valve opening (the gap between the valve body 105 and the seat ring 106). In other words, it adjusts the flow of the fluid.

The positioner 102 detects the lift position of the valve shaft 104, i.e., the actual opening of the valve, from the rotation angle position of the feedback lever 107 connected to the valve shaft 104, and supplies air pressure Po to the actuator 103 according to the difference between the detected actual opening and the set opening.

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

Within the lower flange 109, the bellows 108 is supported between a bellows ring 111 fitted onto the valve shaft 104 and a bellows flange 112 sandwiched between the lower flange 109 and the upper flange 110. Within 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 to further prevent external leakage of fluid. In addition, the lower part of the upper flange 110 serves as a top cover for the lower flange 109.

A valve 100 equipped with such a bellows-like bellows 108 is called a bellows valve. In plants where these valves are installed, efficient maintenance of a large number of valves is required, and a method for detecting damage to bellows valves has been proposed to improve the efficiency of maintenance work (see Patent Document 1).

The valve maintenance support device disclosed in Patent Document 1 is designed to provide an operator with information about the maximum friction force of a bellows valve as a diagnostic index, allowing the operator to estimate whether or not the bellows valve is suspected of being damaged.

However, there are cases where even if the bellows 108 is damaged, the damage does not appear in the friction force detection results. Although leakage of fluid from the bellows 108 is a serious event, the technology disclosed in Patent Document 1 may not be able to detect damage to the bellows 108.

Many valves are used in petrochemical plants and the like. For example, in the example of FIG. 11, valves 100-A and 100-M are arranged in flow path 114-1, and valve 100-C is arranged in flow path 114-3. 115-A, 115-C, and 115-M are flow meters, 116 is a tank, and 117 is a pressure transmitter. In plants where many valves are used like this, further improvements in the efficiency of maintenance work are required.

JP 2019-087003 A

The present invention has been made to solve the above problems, and aims to provide a valve maintenance support device and method that can improve the work efficiency of bellows valve maintenance.

The valve maintenance support device of the present invention includes an opening command value storage unit configured to store data of an opening command value given to a bellows valve in association with an ID of the bellows valve that transmitted the data, a measured opening 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 transmitted the data, a full opening data extraction unit configured to search for data of an opening command value instructing full opening among the opening command values stored in the opening command value storage unit, and to extract, as diagnostic data, an actual opening value of the bellows valve to which the opening command value was given and an actual opening value for a time period corresponding to the opening command value instructing full opening, and The system is characterized by comprising a full-open failure determination unit configured to determine whether a full-open failure state has occurred in a bellows valve that is not fully open when an opening command value indicating full opening has been given based on interruption data; a bellows damage determination unit configured to determine that bellows damage has occurred in the bellows valve when the full-open failure state has occurred multiple times in the same bellows valve and the degree of insufficient opening in each of the multiple full-open failure states monotonically increases; and a determination result presentation unit configured to present the ID of the bellows valve determined by the bellows damage determination unit to have bellows damage as the ID of the valve in which bellows damage has occurred.

In addition , in one configuration example of the valve maintenance support device of the present invention, the bellows damage determination unit is characterized in that it determines that bellows damage has occurred in the bellows valve when the degree of insufficient opening increases monotonically with an approximately constant slope in a graph of the degree of insufficient opening against the number of times the same bellows valve has been in the fully open failure state.

A valve maintenance support method of the present invention includes a first step of storing data of an opening command value given to a bellows valve and an ID of the bellows valve that is a source of the data in association with each other, a second step of storing data of an actual opening value of the bellows valve and an ID of the bellows valve that is a source of the data in association with each other, a third step of searching for data of an opening command value instructing full opening from among the opening command values stored in the first step, and extracting, as diagnostic data, an actual opening value of the bellows valve for which this opening command value was given and an actual opening value for a time period corresponding to the opening command value instructing full opening, and This method is characterized by including a fourth step of determining, based on the diagnostic data, whether or not a fully open failure state has occurred in a bellows valve that has been given an opening command value instructing full opening and that does not fully open; a fifth step of determining that bellows damage has occurred in the bellows valve if the fully open failure state has occurred multiple times in the same bellows valve and the degree of insufficient opening degree for each of the multiple fully open failure states is monotonically increasing; and a sixth step of presenting the ID of the bellows valve determined to have bellows damage in the fifth step as the ID of the valve in which bellows damage has occurred.

Furthermore , in one configuration example of the valve maintenance support method of the present invention, the fifth step is characterized by including a step of determining that bellows damage has occurred in this bellows valve when the degree of insufficient opening increases monotonically with an approximately constant slope in a graph of the degree of insufficient opening against the number of times the same bellows valve has been in the fully open failure state.

According to the present invention, by monitoring the bellows valve for abnormalities when fully open, it is possible to detect fluid leakage from the bellows, and to assist workers in selecting bellows valves as candidates for maintenance. As a result, the present invention can improve the work efficiency of bellows valve maintenance.

FIG. 1 is a block diagram showing the configuration of a valve maintenance support device according to a first embodiment of the present invention. FIG. 2 is a flowchart illustrating the operation of the valve maintenance support device according to the first embodiment of the present invention. FIG. 3 is a flowchart illustrating the operation of the valve maintenance support device according to the first embodiment of the present invention. FIG. 4 is a diagram showing an example of the opening operation of a bellows valve. FIG. 5 is a diagram showing an example in which the degree of insufficient opening increases monotonically at a substantially constant rate. FIG. 6 is a diagram showing an example in which the degree of insufficient opening does not increase monotonically. FIG. 7 is a diagram showing an example in which the degree of insufficient opening increases, but the slope is not substantially constant. FIG. 8 is a diagram showing the configuration of a plant and its equipment management system according to the second embodiment of the present invention. FIG. 9 is a block diagram showing an example of the configuration of a computer that realizes the valve maintenance support device according to the first and second embodiments of the present invention. FIG. 10 is a diagram showing an example of a control valve. FIG. 11 is a diagram showing an example of a number of valves used in a tank of a plant.

[Principle of the Invention]
The inventors have found that even if the damage to the bellows valve is so minor that it is difficult to detect the effect of the damage in the friction force detection, damage accompanied by leakage of fluid from the bellows (108 in FIG. 10) can become a serious event of fluid leakage. When the bellows is damaged, the fluid flowing through the valve penetrates from the outside of the bellows to the inside of the bellows. Furthermore, the expansion and contraction of the bellows' bellows shape caused by the up and down movement of the valve stem (104 in FIG. 10) can act as a driving force for the fluid inside the bellows, causing the fluid to penetrate into the top cover (the lower part of the top flange 110 in FIG. 10) near the bellows joint. Since it is not originally expected that the top cover will come into contact with the fluid, the leakage of the fluid from the bellows can be detected by monitoring the abnormality of the valve being fully open due to the intrusion of the fluid.

Once fluid has entered the top lid, it will not disappear. Therefore, when the degree to which the valve is not fully open at a constant pace increases monotonically, there is a high possibility of a fluid leak. In other words, if the valve becomes abnormally fully open and then suddenly resolves on its own, it is reasonable to assume that this is due to temporary adhesion of scale (such as carbon-based substances contained in the fluid flowing through the valve) in a location away from the bellows.

[First embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of a valve maintenance support device according to a first embodiment of the present invention. In the following embodiments, in order to simplify the explanation, examples of IDs (identification information) of valves and the like are assumed to be simpler than those used in an actual plant.

The valve maintenance support device includes a valve ID storage unit 1 that stores in advance the IDs of multiple bellows valves that are candidates for maintenance, an opening acquisition unit 2 that acquires an opening command value given to a bellows valve and an actual opening value of the bellows valve, an opening command value storage unit 3 that stores the opening command value data in association with the ID of the bellows valve that transmitted the data, and an opening measurement value storage unit 4 that stores the actual opening value data in association with the ID of the bellows valve that transmitted the data, and searches for opening command value data that indicates full opening among the opening command values stored in the opening command value storage unit 3, and calculates the actual opening value of the bellows valve to which this opening command value was given. The system further includes a fully open data extraction unit 5 that extracts as diagnostic data the actual opening value for the time period corresponding to the opening command value instructing full opening, a fully open failure determination unit 6 that determines whether a fully open failure state occurs in which the bellows valve given an opening command value instructing full opening does not fully open based on the diagnostic data, a bellows damage determination unit 7 that determines that the bellows valve has bellows damage when a fully open failure state occurs multiple times in the same bellows valve and the degree of insufficient opening degree for each of these multiple fully open failure states increases monotonically, and a determination result presentation unit 8 that presents (displays) the ID of the bellows valve that has been determined to have bellows damage.

Figures 2 and 3 are flow charts explaining the operation of the valve maintenance support device of this embodiment. In this embodiment, for example, assume that there are 26 valves in a plant, and that these 26 valves are pre-assigned unique IDs "A", "B", "C", ..., "M", ..., "X", "Y", and "Z". In particular, it is assumed that the valves with valve IDs "A", "C", and "M" are bellows valves equipped with bellows, and that these IDs "A", "C", and "M" are pre-stored in the valve ID storage unit 1.

The positioner (102 in Fig. 10) used in each bellows valve supplies air pressure to the actuator (103 in Fig. 10) according to the difference between the opening command value SP (stem position command value) given by the higher-level device and the actual opening value PV (stem position measurement value) of the bellows valve.

The opening acquisition unit 2 acquires data on the opening command value SP and the actual opening value PV from the positioner of each bellows valve for a bellows valve whose valve ID is registered in the valve ID storage unit 1 (step S100 in Figure 2).

The opening degree acquisition unit 2 associates the data of the opening degree command value SP with the ID of the bellows valve that sent the data and information on the time when the data was received, and stores them in the opening degree command value storage unit 3 (step S101 in FIG. 2). The opening degree acquisition unit 2 also associates the data of the actual opening degree value PV with the ID of the bellows valve that sent the data and information on the time when the data was received, and stores them in the opening degree measurement value storage unit 4 (step S102 in FIG. 2).

The ID of the bellows valve can be acquired by the opening acquisition unit 2 from the valve ID that is added to the data of the opening command value SP and the actual opening value PV by the bellows valve positioner and transmitted. The time information can be added by the bellows valve positioner or by the opening acquisition unit 2.

In this way, by repeating the processing of steps S100 to S102, time series data for the opening command value SP and the actual opening value PV are stored in the opening command value memory unit 3 and the opening measurement value memory unit 4.

Next, the full-open data extraction unit 5 searches for data of the opening command value SP instructing full opening among the opening command values SP stored in the opening command value storage unit 3 (step S103 in FIG. 3). Then, the full-open data extraction unit 5 extracts, from among the actual opening values PV stored in the opening measurement value storage unit 4, the actual opening value PV of the bellows valve (the bellows valve with the same ID) to which the opening command value SP instructing full opening was given, and the actual opening value PV for the time period corresponding to the opening command value SP instructing full opening, as diagnostic data (step S104 in FIG. 3).

The actual opening value PV during the time period corresponding to the opening command value SP commanding full open refers to the actual opening value PV from the same time as the opening command value SP commanding full open to the time after the predetermined time Top has elapsed. There is a delay in the response of the bellows valve to the opening command value SP. Therefore, for example, the above-mentioned predetermined time Top can be set to a time longer than the time required for a normal bellows valve to go from 0% to 100% opening. A normal bellows valve will be fully open within the predetermined time Top from the time when the opening command value SP commanding full open is given.

The full-open failure determination unit 6 determines whether a full-open failure state occurs in which the bellows valve to which the opening command value SP instructing full opening has been given, in which the valve does not fully open, based on the diagnostic data extracted for the opening command value SP instructing full opening (step S105 in FIG. 3).

Figures 4(A) and 4(B) show an example of the opening operation of a bellows valve. In the example of Figure 4(A), the actual opening value PV of the bellows valve given an opening command value SP instructing full opening becomes 100% within the specified time Top. In this case, the full-open failure determination unit 6 determines that the bellows valve is not in a full-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 specified time Top. In this case, the full-open failure determination unit 6 determines that a full-open failure state has occurred in the bellows valve.

When it is determined that the bellows valve is in a fully open failure state and the same bellows valve has experienced multiple fully open failures (YES in step S106 in FIG. 3), the bellows damage determination unit 7 determines whether the degree of insufficient opening Dif for each of the multiple fully open failures is monotonically increasing (step S107 in FIG. 3).

The degree of insufficient opening Dif is the difference between the opening command value SP, which indicates full opening (100%), and the corresponding maximum value of the actual opening value PV, as shown in FIG. 4(B). The period from when the opening command value SP indicates full opening until it becomes a value other than full opening is counted as one opening operation, and the state in which the bellows valve does not become fully open during this one opening operation is counted as one fully open insufficient state. The degree of insufficient opening Dif can be obtained during each judgment process by the full opening insufficiency judgment unit 6.

When the degree of insufficient opening Dif of the same bellows valve in a multiple full-open failure state increases monotonically (YES in step S107), the bellows damage determination unit 7 determines that bellows damage has occurred in this bellows valve (step S108 in FIG. 3). At this time, when the degree of insufficient opening Dif of the same bellows valve increases monotonically with a substantially constant slope, the bellows damage determination unit 7 determines that bellows damage has occurred, and excludes cases where the slope is not substantially constant.

For example, FIG. 5 shows a case where the degree of insufficient opening Dif increases monotonically at a substantially constant rate. On the other hand, FIG. 6 shows a case where this does not apply, and FIG. 7 shows a case where the degree of insufficient opening Dif increases, but the rate is not substantially constant.

The method for determining whether the degree of insufficient opening Dif increases monotonically with a substantially constant gradient may be determined appropriately. For example, when the change in the degree of insufficient opening Dif is linearly approximated by the least squares method, if the coefficient of determination ^R2 (0≦ ^R2 ≦1) is equal to or greater than a predetermined value TH (TH is a real number in the range of 0<TH≦1) and is equal to or less than 1, the bellows damage determination unit 7 may determine that the degree of insufficient opening Dif increases monotonically with a substantially constant gradient. This method is only one example, and it goes without saying that other determination methods may be used for the determination. The reason why the degree of insufficient opening Dif increases monotonically with a substantially constant gradient is because the fluid gradually penetrates into the upper cover while being accompanied by the viscous resistance of the fluid. However, it is preferable to regard the case as shown in FIG. 7 as an abnormality other than the bellows damage (such as the adhesion of scale that does not peel off).

In addition, in this embodiment, if the same bellows valve experiences multiple full-open failures, it is determined whether the degree of insufficient opening Dif is monotonically increasing. The multiple times may be, for example, N times (N is an integer equal to or greater than 3) or more.

The determination result presentation unit 8 presents to the worker the valve IDs of the bellows valves that have been determined to have bellows damage among the bellows valves whose valve IDs are registered in the valve ID storage unit 1 (Figure 3, step S109).

However, the determination result presentation unit 8 may present (display) information on either "damaged" or "not damaged" for all bellows valves whose valve IDs are registered in the valve ID storage unit 1. In this case, the worker (operator) can also check the valve IDs of bellows valves that were not damaged as a result of the bellows damage determination.

In this way, the processing of steps S100 to S109 in FIG. 3 is performed periodically. Note that in the flowchart of FIG. 3, it is determined that bellows damage has occurred in a bellows valve in which the degree of insufficient opening Dif increases monotonically at a substantially constant rate, but the processing by 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 that the full-open failure determination unit 6 has determined to be in a full-open failure state as the ID of the valve with bellows damage.

In this embodiment, by monitoring the bellows valve for abnormalities when fully open, it is possible to detect fluid leakage from the bellows, and to assist workers in selecting bellows valves as candidates for maintenance.

[Second embodiment]
Next, a second embodiment of the present invention will be described. This embodiment describes an implementation example of the first embodiment. Fig. 8 is a diagram showing the configuration of a plant and its equipment management system, and the same components as those in Fig. 11 are given the same reference numerals.

In equipment management systems for petroleum and chemical plants, a management device 10 is provided to control and manage each piece of equipment in the plant. The valve ID storage unit 1, opening acquisition unit 2, opening command value storage unit 3, and opening measurement value storage unit 4 described in the first embodiment handle a huge amount of plant-specific information, so it is preferable that they are implemented in the management device 10.

On the other hand, the full-open data extraction unit 5, full-open deficiency determination unit 6, bellows damage determination unit 7, and determination result presentation unit 8 provide processing that is required in principle only when determining whether valve maintenance is required. Also, maintenance implementers (workers at the maintenance contracted company) generally carry out plant maintenance on behalf of the plant owner company. Therefore, assuming that an unspecified number of plants will be the target, it is preferable to implement the full-open data extraction unit 5, full-open deficiency determination unit 6, bellows damage determination unit 7, and determination result presentation unit 8 in a portable computer 11 carried around by a worker (operator) at the maintenance contracted company.

The plant management device 10 and the computer 11 are temporarily connected to each other using a communication function such as Ethernet (registered trademark) when maintenance work is performed.
When an operator starts the application software on the computer 11, the CPU (Central Processing Unit) of the computer 11 executes processing according to the program stored in the memory, and realizes the functions of the full-open data extraction unit 5, the full-open failure judgment unit 6, the bellows damage judgment unit 7, and the judgment result presentation unit 8.

The judgment result presentation unit 8 reads the valve ID from the valve ID storage unit 1 on the management device 10, and also reads the judgment result of the bellows damage judgment unit 7 (or the full-open failure judgment unit 6), and displays the ID of the bellows valve that has been judged to have bellows damage on the display of the computer 11 (Figure 3, step S109).

The operator checks the bellows valves that require special attention for inspection based on the displayed valve IDs. After checking the displayed items, the operator disconnects the computer 11 from the management device 10.
In this manner, the valve maintenance support device described in the first embodiment can be applied to an actual plant.

The valve maintenance support device described in the first and second embodiments can be realized by a computer equipped with a CPU, a storage device, and an interface, and a program for controlling these hardware resources. An example of the configuration of this computer is shown in Fig. 9. The computer is equipped with a CPU 300, a storage device 301, and an interface device (I/F) 302. For example, a valve, a management device, a display, etc. are connected to the I/F 302. In such a computer, a program for realizing the valve maintenance support method of the present invention is stored in the storage device 301. The CPU 300 executes the processing described in the first and second embodiments in accordance with the program stored in the storage device 301.
When the valve maintenance support device is implemented separately in the management device 10 and the computer 11 as in the second embodiment, each of them may be realized with the configuration shown in FIG.

The present invention can be applied to technology that assists in valve maintenance work.

1... Valve ID storage unit, 2... Opening degree acquisition unit, 3... Opening degree command value storage unit, 4... Opening degree measurement value storage unit, 5... Full opening data extraction unit, 6... Full opening failure determination unit, 7... Bellows damage determination unit, 8... Determination result presentation unit, 10... Management device, 11... Computer.

Claims (4)

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 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 sender of the data;
a full-open data extraction unit configured to search for data of an opening command value instructing full opening among the opening command values stored in the opening command value storage unit, and to extract, as diagnostic data, an actual opening value of the bellows valve to which the opening command value was given, and an actual opening value of a time period corresponding to the opening command value instructing full opening;
a full-open failure determination unit configured to determine whether or not a full-open failure state occurs in which the bellows valve is not fully opened when an opening command value instructing full opening is given based on the diagnostic data; and
a bellows damage determination unit configured to determine that a bellows valve has been damaged when the full-open failure state occurs multiple times in the same bellows valve and the degree of insufficient opening in each of the multiple full-open failure states increases monotonically;
and a judgment result presentation unit configured to present the ID of a bellows valve for which the bellows damage determination unit has determined that bellows damage has occurred as the ID of a valve in which bellows damage has occurred. 2. The valve maintenance support device according to claim 1 ,
The valve maintenance support device is characterized in that the bellows damage determination unit determines that bellows damage has occurred in the bellows valve when the degree of insufficient opening increases monotonically with a substantially constant slope in a graph of the degree of insufficient opening against the number of times the same bellows valve has been in the fully open failure state. A first step of storing data of an opening command value given to a bellows valve in association with an ID of the bellows valve that is a source of the data;
a second step of storing the data of the actual opening value of the bellows valve in association with the ID of the bellows valve that is the sender of the data;
a third step of searching for data of an opening command value instructing full opening from among the opening command values stored in the first step, and extracting, as diagnostic data, an actual opening value of the bellows valve to which this opening command value was given and an actual opening value in a time period corresponding to the opening command value instructing full opening;
a fourth step of determining whether or not a full-open insufficient state occurs in the bellows valve to which an opening command value instructing full opening is given based on the diagnostic data; and
a fifth step of determining that a bellows valve is damaged when the full-open failure state occurs multiple times in the same bellows valve and the degree of insufficient opening in each of the multiple full-open failure states increases monotonically;
and a sixth step of presenting the ID of the bellows valve determined to have bellows damage in the fifth step as the ID of the valve in which bellows damage has occurred. 4. The valve maintenance support method according to claim 3 ,
the fifth step including a step of determining that bellows damage has occurred in the bellows valve when the degree of insufficient opening increases monotonically with a substantially constant slope in a graph of the degree of insufficient opening against the number of times the same bellows valve has been in the fully open failure state.

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