A bypass isolation valve control method in oil product movement operation

Abstract

The application provides a bypass isolation valve control method in oil product moving operation, relates to the technical field of industrial equipment, and comprises the following steps: S1, generating an operation main line, a first bypass and a first isolation valve; S2, acquiring a second bypass and a second isolation valve; S3, judging whether the first isolation valve is closed during operation; if yes, the operation is completed; otherwise, S4 is executed; S4, judging whether the second isolation valve is closed; if yes, the operation is completed; otherwise, the first isolation valve is closed, and S5 is executed; S5, judging whether the first isolation valve is normally closed; if yes, the operation is completed; otherwise, the second isolation valve is closed, and S6 is executed; S6, judging whether the second isolation valve is normally closed; if yes, the operation is completed; otherwise, an alarm is sent. The first bypass and the second bypass on the operation main line are generated, the state of the first isolation valve and the second isolation valve is managed, the safety of the oil product moving operation is ensured, the number of operation isolation valves is effectively reduced in the second detection mode, and the operation efficiency is increased.

Description

Technical Field

[0001] This invention relates to the field of industrial equipment technology, and in particular, to a method for controlling a bypass isolation valve in oil product mobile operations. Background Technology

[0002] In the oil refining and petrochemical industry, the Oil Moving System (OMS) is a system used to move crude oil and its products through pipelines. It includes equipment and equipment status management, movement path optimization management, and drive equipment safety management. The main equipment control components operate within a Distributed Control System (DCS). Before executing an oil moving task, the OMS task system generates the movement path. During the task execution, equipment along the path needs to perform start-up or shutdown actions according to its type and location, following specific rules. The system also monitors equipment status and executes emergency handling logic when necessary.

[0003] When an Oil Movement Control System (OMS) performs its tasks, the medium is generally isolated by a primary bypass to prevent it from flowing to a larger area and causing contamination or waste. However, there are special cases, such as when the primary bypass valve is damaged, requiring the closure of the corresponding secondary bypass, or when all valves connected to the primary bypass isolation device are already closed, achieving the isolation purpose, in which case it is not necessary to close the primary bypass valve for further media isolation. By calculating the path of the secondary bypass, the workload in the tank farm can be increased to some extent, while reducing equipment operation and thus improving operational efficiency.

[0004] Based on this concept, the present invention designs a reasonable bypass isolation valve control method for oil product movement operations, thereby improving the operational efficiency of oil product movement control. Summary of the Invention

[0005] The purpose of this invention is to provide a bypass isolation valve control method in oil product relocation operations. By generating a primary bypass and a secondary bypass on the main operation route, the method manages the status of the primary isolation valve on the primary bypass and the secondary isolation valve on the secondary bypass, ensuring the safety of oil product relocation operations. Furthermore, through a two-stage detection method, the method effectively reduces the number of isolation valves to be operated, reduces the workload, and increases operational efficiency. This method can be used flexibly when multiple oil products are relocated simultaneously.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A method for controlling a bypass isolation valve in oil product relocation operations, the method comprising the following steps: S1: Generate the transport path for oil product movement operations as the main operation route, and obtain the primary bypass and the primary isolation valve set on the primary bypass; S2: Obtain the secondary bypass connected to the primary bypass and the secondary isolation valve installed on the secondary bypass; S3: During oil relocation operations, determine whether all primary isolation valves are closed. If yes, the operation is complete; otherwise, proceed to step S4. S4: Determine if the secondary isolation valve is closed. If yes, the operation is complete; otherwise, close the primary isolation valve and proceed to step S5. S5: Determine if the primary isolation valve is closed normally. If yes, the operation is complete; otherwise, close the secondary isolation valve and proceed to step S6. S6: Determine if the secondary isolation valve is closed normally. If yes, the operation is complete; otherwise, issue an alarm.

[0007] In a preferred embodiment of the present invention, step S1 is performed to generate the main operating route and obtain the primary bypass and the primary isolation valve. The specific steps are as follows: S11: Obtain the starting point of the oil product movement operation, identify pipelines in the current pipeline network that are not currently being transported, and generate the main operation route; S12: Obtain all pipelines that intersect with the main work route to obtain the first-level bypass; S13: Determine whether an isolation valve is installed at the intersection of the primary bypass and the main working road. If so, mark the isolation valve and proceed directly to step S16; otherwise, proceed to step S14. S14: Determine whether the end of the primary bypass furthest from the main working route is a pipeline currently carrying out operations. If so, mark the primary bypass as a pipeline currently carrying out operations and return to step S11; otherwise, proceed to step S15. S15: Obtain all isolation valves on the primary bypass and mark them; S16: Use the marked isolation valve as the primary isolation valve.

[0008] As a preferred embodiment of the present invention, when performing step S12, all pipelines that intersect with the primary bypass and for which there is no isolation valve at the intersection point are considered as primary bypasses.

[0009] As a preferred embodiment of the present invention, when performing step S2, the secondary bypass and the secondary isolation valve are obtained, and the specific steps are as follows: S21: Equipment on the main road and primary bypass for statistical work, used as marking equipment; S22: Starting from all valves on the primary bypass, traverse all pipelines in the direction of oil diffusion, and treat all nodes on the pipelines as leaf nodes. S23: Determine whether the leaf node has encountered a marked device. If so, stop the search and proceed directly to step S25; otherwise, proceed to step S24. S24: Until the leaf node is an isolation valve; S25: Connect all the leaf nodes found in the search to form a pipeline as a secondary bypass, and use all the isolation valves on the secondary bypass as secondary isolation valves.

[0010] As a preferred embodiment of the present invention, when performing step S22, all intersections that intersect with the search pipeline and where no isolation valve is installed at the intersection point are treated as leaf nodes.

[0011] As a preferred embodiment of the present invention, when performing step S3, if the primary isolation valves are not completely closed, the unclosed primary isolation valves are recorded and designated as the first isolation valve.

[0012] In a preferred embodiment of the present invention, when performing step S4, the primary bypass where the first isolation valve is located is obtained, and all secondary bypasses connected to the primary bypass and the secondary isolation valves on the secondary bypasses are obtained and denoted as the second isolation valves. It is determined whether all the second isolation valves are closed. If so, the operation is completed; otherwise, the unclosed second isolation valves are obtained and denoted as the third isolation valves. All primary bypasses connected to the secondary bypasses where the third isolation valve is located and the primary isolation valves on the primary bypasses are obtained and denoted as the fourth isolation valves. The fourth isolation valves are closed, and step S5 is performed.

[0013] As a preferred embodiment of the present invention, when performing step S5, it is determined whether all the fourth isolation valves are closed normally. If so, the operation is completed; otherwise, the fourth isolation valves that are not closed normally are recorded as the fifth isolation valves. The primary bypass where the fifth isolation valve is located is obtained, and all the secondary bypasses connected to the primary bypasses and the secondary isolation valves on the secondary bypasses are obtained and recorded as the sixth isolation valves. The sixth isolation valves are closed, and step S6 is performed.

[0014] As a preferred embodiment of the present invention, when performing step S6, it is determined whether all the sixth isolation valves are closed normally. If so, the operation is completed; otherwise, information on the sixth isolation valves that are not closed normally is obtained and merged into the alarm information for issuance.

[0015] As a preferred embodiment of the present invention, if the primary isolation valve fails to close properly when performing step S5, the secondary isolation valve is closed, a secondary alarm is issued, and step S6 is performed. If the secondary isolation valve fails to close properly during step S6, a primary alarm will be issued.

[0016] The beneficial effects of the bypass isolation valve control method in oil product relocation operations of the present invention are as follows: 1. The design is reasonable. It generates primary and secondary bypasses on the main work route and effectively manages the entire main work route through the distribution of primary and secondary bypasses. 2. High safety: The status management of the primary isolation valve on the primary bypass and the secondary isolation valve on the secondary bypass allows the operation to continue even if the primary bypass fault is detected, by closing the secondary bypass isolation valve, thus ensuring the safety of oil product movement operations. 3. High efficiency: Through a two-stage detection method, the number of isolation valves to be operated is effectively reduced, the workload is reduced, and the work efficiency is increased; 4. Flexible use: When generating primary and secondary bypasses on the main operation route, it can effectively coordinate with other routes for oil product movement operations, ensuring safety and no impact between multiple oil product movement pipelines. It can be used flexibly when multiple oil products are moved simultaneously. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of a bypass isolation valve control method for oil product movement operations according to the present invention. Detailed Implementation

[0018] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0019] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement of modules and structures set forth in these embodiments does not limit the scope of the invention.

[0020] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0021] Techniques, methods, and systems known to a person skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the license specification.

[0022] Example 1: As Figure 1 The illustration shown is merely one embodiment of the present invention, a method for controlling a bypass isolation valve in oil product relocation operations, the method comprising the following steps: A method for controlling a bypass isolation valve in oil product relocation operations, the method comprising the following steps: S1: Generate the transport path for oil product movement operations as the main operation route, and obtain the primary bypass and the primary isolation valve set on the primary bypass; When the Oil Movement Control System (OMS) performs its tasks, it needs to first obtain the path of oil movement. That is, it needs to find the most suitable pipeline for oil transportation in all pipeline networks as the main operation route. This main operation route should comply with oil operation standards, that is, the main operation route should have all the equipment for handling oil during the oil movement process.

[0023] Of course, there may be more than one oil relocation operation in the pipeline network. Each time an oil relocation operation arrives, it will occupy a part of the pipeline. When the next oil relocation operation is carried out, this part of the pipeline will be in an unselectable state. That is, a pipeline that meets the operation standards will be selected from the available pipelines as the main route for this oil relocation operation.

[0024] After selecting the main work route, it is necessary to find the pipeline that intersects with the main work route, which is called the first-level bypass. The isolation valve on the first-level bypass is the first-level isolation valve.

[0025] Specifically, in step S1, the main work route is generated, and the primary bypass and primary isolation valve are obtained. The specific steps are as follows: S11: Obtain the starting point of the oil product movement operation, identify pipelines in the current pipeline network that are not currently being transported, and generate the main operation route; S12: Obtain all pipelines that intersect with the main work route to obtain the first-level bypass; S13: Determine whether an isolation valve is installed at the intersection of the primary bypass and the main working road. If so, mark the isolation valve and proceed directly to step S16; otherwise, proceed to step S14. S14: Determine whether the end of the primary bypass furthest from the main working route is a pipeline currently carrying out operations. If so, mark the primary bypass as a pipeline currently carrying out operations and return to step S11; otherwise, proceed to step S15. S15: Obtain all isolation valves on the primary bypass and mark them; S16: Use the marked isolation valve as the primary isolation valve.

[0026] In step S12, all pipelines that intersect with a primary bypass and whose intersection point does not have an isolation valve are considered primary bypasses. That is, the first pipeline that intersects with the main working route is considered a primary bypass. If a second pipeline is connected to the first pipeline, but there is no isolation valve at the intersection of the second and first pipelines, then the second pipeline is also considered a primary bypass. If a third pipeline intersects with the second pipeline and an isolation valve is installed at the intersection point, then the third pipeline is not considered a primary bypass, but the isolation valve at the intersection of the third and second pipelines needs to be considered a primary isolation valve.

[0027] When performing step S14, if the other end of the primary bypass is the main operating route for other oil product relocation operations, then the primary bypasses for the two oil product relocation operations are the same pipeline, which poses a safety hazard. The main operating route needs to be redrawn, and the new main operating route needs to bypass the intersection of the old primary bypass and the old main operating route to ensure operational safety.

[0028] S2: Obtain the secondary bypass connected to the primary bypass and the secondary isolation valve installed on the secondary bypass; Once the primary bypass is determined, the main operating route is also determined. At this point, a full search of the primary bypass can be performed to ensure that all secondary bypasses and secondary isolation valves on the secondary bypasses are found without any blind spots.

[0029] Specifically, during step S2, the secondary bypass and secondary isolation valve are obtained. The specific steps are as follows: S21: Equipment on the main road and primary bypass for statistical work, used as marking equipment; S22: Starting from all valves on the primary bypass, traverse all pipelines in the direction of oil diffusion, and treat all nodes on the pipelines as leaf nodes. S23: Determine whether the leaf node has encountered a marked device. If so, stop the search and proceed directly to step S25; otherwise, proceed to step S24. S24: Until the leaf node is an isolation valve; S25: Connect all the leaf nodes found in the search to form a pipeline as a secondary bypass, and use all the isolation valves on the secondary bypass as secondary isolation valves.

[0030] In summary, after statistically analyzing the main line equipment and the first-level bypass equipment, all valves of the first-level bypass are used as the root node (starting point) of the search tree. All leaf nodes are traversed in the direction of medium diffusion (non-main line direction) until a valve is encountered at each leaf node (if a main line equipment or a first-level bypass equipment is encountered during the traversal, the search is stopped; if a special equipment such as a pump is encountered, the search is also stopped). Then, the valve type nodes of all the leaf nodes reached are collected as the second-level isolation valves.

[0031] Of course, when executing step S22, all intersections that intersect with the search pipeline and where no isolation valve is set at the intersection point are treated as leaf nodes.

[0032] S3: During oil relocation operations, determine whether all primary isolation valves are closed. If yes, the operation is complete; otherwise, proceed to step S4. If all primary bypasses are isolated, there is no risk of medium leakage on the main operating line, and oil relocation operations can be carried out directly; otherwise, the primary bypasses may not be isolated, requiring further operations.

[0033] S4: Determine if the secondary isolation valve is closed. If yes, the operation is complete; otherwise, close the primary isolation valve and proceed to step S5. If the primary isolation valve is not closed, but all the secondary isolation valves on the secondary bypass are closed, then the purpose of oil isolation has been achieved. There is no need to close the primary isolation valve to isolate the oil medium. At this time, oil movement operations can be carried out directly, reducing the workload (of closing the primary isolation valve).

[0034] If the secondary isolation valves are not all closed, then in order to isolate the oil medium, the isolation valves need to be closed to isolate the oil. Since the number of primary isolation valves is definitely no greater than the number of secondary isolation valves, closing the primary isolation valves is the optimal choice with the least workload. In this case, the primary isolation valves should be closed.

[0035] S5: Determine if the primary isolation valve is closed normally. If yes, the operation is complete; otherwise, close the secondary isolation valve and proceed to step S6. If the primary isolation valve can close normally, then the oil relocation operation can be carried out normally; otherwise, if the primary isolation valve cannot close normally, there is a malfunction or jamming of the primary isolation valve. In this case, in order to ensure the isolation of the oil medium, the secondary isolation valve must be closed to ensure the safety of the oil relocation operation.

[0036] S6: Determine if the secondary isolation valve is closed normally. If yes, the operation is complete; otherwise, issue an alarm.

[0037] Finally, when the secondary isolation valve is closed normally, oil relocation operations can be carried out normally; however, if the secondary isolation valve cannot be closed normally, there is a malfunction or jamming of the secondary isolation valve. At this time, the oil medium can no longer be effectively isolated. During oil relocation operations, the oil will spread to a large part of the pipeline, causing too great safety hazards. An alarm needs to be issued and the oil relocation operation needs to be stopped.

[0038] Example 2: As before Figure 1 The illustration shown is merely one embodiment of the present invention. Based on Embodiment 1, the present invention provides a bypass isolation valve control method for oil product movement operations, which includes two isolation valve control modes: Method 1: After obtaining the main working route, primary bypass, primary isolation valve, secondary bypass, and secondary isolation valve (after executing steps S1 and S2), when performing oil product movement operations (when executing step S3), obtain the location where the oil product has arrived, obtain the primary bypass ahead of the location, and perform secondary detection on this primary bypass (i.e., execute steps S3 to S6). That is, based on the primary bypass as a single judgment basis, identify each primary bypass and its connected secondary bypass one by one, and perform oil product operations. Once a primary bypass is identified, the operation will either proceed normally or an alarm will be issued. After completion, the next primary bypass will be identified, and so on, until all primary bypasses are identified. Method 2: After obtaining the main working route, primary bypass, primary isolation valve, secondary bypass, and secondary isolation valve (after completing steps S1 and S2), before performing the oil product relocation operation (before performing step S3), perform a full inspection of all primary and secondary bypasses (i.e., perform steps S3 to S6). If the identification is successful (i.e., the operation is completed), then proceed with the oil product relocation operation; otherwise, if the identification fails (i.e., an alarm is issued), terminate the operation.

[0039] In this invention, method one is more efficient and can control the isolation valve while operating, but safety is not guaranteed. If the primary and secondary isolation valves at the primary bypass point fail and open, oil leakage is unavoidable and poses a safety hazard. Therefore, method two is used most of the time.

[0040] Method 2 is still highly efficient (but less efficient than Method 1), and can effectively ensure the safety of oil product movement, thus ensuring both safety and high efficiency, and facilitating various oil product movement operations.

[0041] Of course, in Method 2, after executing step S6, the main working route connected to the isolation valve that cannot be closed normally is marked as a working pipeline, and the process returns to step S1 to select a new main working route.

[0042] Example 3: As before Figure 1 The above is merely one embodiment of the present invention. Based on embodiment two, in the bypass isolation valve control method for oil product moving operations of the present invention, in the case of mode two: when executing step S3, if the first-level isolation valve is not completely closed, the unclosed first-level isolation valve is recorded and designated as the first isolation valve.

[0043] Then, when executing step S4, the primary bypass where the first isolation valve is located is obtained, and all secondary bypasses connected to the primary bypass and the secondary isolation valves on the secondary bypasses are obtained and denoted as the second isolation valves. It is determined whether all the second isolation valves are closed. If so, the operation is completed; otherwise, the unclosed second isolation valves are obtained and denoted as the third isolation valves. All primary bypasses connected to the secondary bypasses where the third isolation valve is located and the primary isolation valves on the primary bypasses are obtained and denoted as the fourth isolation valves. The fourth isolation valves are closed, and step S5 is executed.

[0044] Next, when executing step S5, determine whether all the fourth isolation valves are closed normally. If so, the operation is completed; otherwise, record the fourth isolation valves that are not closed normally as the fifth isolation valve, obtain the first-level bypass where the fifth isolation valve is located, obtain all the second-level bypasses connected to the first-level bypass and the second-level isolation valves on the second-level bypasses, and record them as the sixth isolation valve. Close the sixth isolation valve and execute step S6.

[0045] Finally, when executing step S6, it is determined whether all the sixth isolation valves are closed normally. If so, the operation is completed; otherwise, the information of the sixth isolation valves that are not closed normally is obtained, merged into the alarm information and issued.

[0046] Of course, when executing step S6, information about the fifth isolation valve that was not properly closed is also obtained and merged into the alarm information for issuance.

[0047] To further ensure the safety of the pipeline network, a tiered alarm system should be implemented, namely: If the primary isolation valve fails to close properly during step S5, then the secondary isolation valve will be closed, a secondary alarm will be issued, and step S6 will be executed. If the secondary isolation valve fails to close properly during step S6, a primary alarm will be issued.

[0048] A level 2 alarm simply notifies maintenance personnel to repair the damaged primary isolation valve after the work is completed (or after the work is stopped); a level 1 alarm is a serious alarm, requiring maintenance personnel to immediately set out to repair both the primary and secondary isolation valves.

[0049] This invention discloses a bypass isolation valve control method for oil product relocation operations. By generating a primary bypass and a secondary bypass on the main operation route, the method manages the status of the primary isolation valve on the primary bypass and the secondary isolation valve on the secondary bypass, ensuring the safety of oil product relocation operations. Furthermore, through a two-stage detection method, the method effectively reduces the number of isolation valves to be operated, reduces workload, and increases operational efficiency. It can be flexibly used when multiple oil products are relocated simultaneously.

[0050] This invention is not limited to the specific embodiments described above, and various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made to the above embodiments based on the technical essence of this invention should be included within the scope of protection of this invention.

Claims

1. A method for controlling a bypass isolation valve in oil product relocation operations, characterized in that: The method includes the following steps: S1: Generate the transport path for oil product movement operations as the main operation route, and obtain the primary bypass and the primary isolation valve set on the primary bypass; S2: Obtain the secondary bypass connected to the primary bypass and the secondary isolation valve installed on the secondary bypass; S3: During oil relocation operations, determine whether the primary isolation valve is closed. If yes, the operation is complete; otherwise, proceed to step S4. S4: Determine if the secondary isolation valve is closed. If yes, the operation is complete; otherwise, close the primary isolation valve and proceed to step S5. S5: Determine if the primary isolation valve is closed normally. If yes, the operation is complete; otherwise, close the secondary isolation valve and proceed to step S6. S6: Determine if the secondary isolation valve is closed normally. If yes, the operation is complete; otherwise, issue an alarm.

2. The bypass isolation valve control method in oil product mobile operations according to claim 1, characterized in that: Execute step S1 to generate the main operating route and obtain the primary bypass and primary isolation valve. The specific steps are as follows: S11: Obtain the starting point of the oil product movement operation, identify pipelines in the current pipeline network that are not currently being transported, and generate the main operation route; S12: Obtain all pipelines that intersect with the main work route to obtain the first-level bypass; S13: Determine whether an isolation valve is installed at the intersection of the primary bypass and the main working road. If so, mark the isolation valve and proceed directly to step S16; otherwise, proceed to step S14. S14: Determine whether the end of the primary bypass furthest from the main working route is a pipeline currently carrying out operations. If so, mark the primary bypass as a pipeline currently carrying out operations and return to step S11; otherwise, proceed to step S15. S15: Obtain all isolation valves on the primary bypass and mark them; S16: Use the marked isolation valve as the primary isolation valve.

3. A bypass isolation valve control method for oil product relocation operations according to claim 2, characterized in that: When performing step S12, all pipelines that intersect with the primary bypass and for which there is no isolation valve at the intersection are considered as primary bypasses.

4. The bypass isolation valve control method in oil product mobile operations according to claim 2, characterized in that: When performing step S2, the secondary bypass and secondary isolation valve are obtained. The specific steps are as follows: S21: Equipment on the main road and primary bypass for statistical work, used as marking equipment; S22: Starting from all valves on the primary bypass, traverse all pipelines in the direction of oil diffusion, and treat all nodes on the pipelines as leaf nodes. S23: Determine whether the leaf node has encountered a marked device. If so, stop the search and proceed directly to step S25; otherwise, proceed to step S24. S24: Until the leaf node is an isolation valve; S25: Connect all the leaf nodes found in the search to form a pipeline as a secondary bypass, and use all the isolation valves on the secondary bypass as secondary isolation valves.

5. A bypass isolation valve control method for oil product mobile operations according to claim 4, characterized in that: When performing step S22, all intersections that intersect with the search pipeline and where no isolation valve is set at the intersection point are treated as leaf nodes.

6. The bypass isolation valve control method in oil product mobile operations according to claim 1, characterized in that: When performing step S3, if the primary isolation valves are not all closed, record the unclosed primary isolation valves as the first isolation valve.

7. A bypass isolation valve control method for oil product relocation operations according to claim 6, characterized in that: When executing step S4, obtain the primary bypass where the first isolation valve is located, obtain all secondary bypasses connected to the primary bypass and the secondary isolation valves on the secondary bypasses, and record them as the second isolation valves. Determine whether all the second isolation valves are closed. If so, the operation is completed; otherwise, obtain the unclosed second isolation valves and record them as the third isolation valves. Obtain all primary bypasses connected to the secondary bypasses where the third isolation valve is located and the primary isolation valves on the primary bypasses, and record them as the fourth isolation valves. Close the fourth isolation valves and execute step S5.

8. A bypass isolation valve control method for oil product relocation operations according to claim 7, characterized in that: When executing step S5, determine whether all the fourth isolation valves are closed normally. If so, the operation is completed; otherwise, record the fourth isolation valves that are not closed normally as the fifth isolation valve, obtain the primary bypass where the fifth isolation valve is located, obtain all the secondary bypasses connected to the primary bypass and the secondary isolation valves on the secondary bypasses, and record them as the sixth isolation valve, close the sixth isolation valve, and execute step S6.

9. A method for controlling a bypass isolation valve in oil product relocation operations according to claim 8, characterized in that: When executing step S6, it is determined whether all the sixth isolation valves are closed normally. If so, the operation is completed; otherwise, the information of the sixth isolation valves that are not closed normally is obtained, merged into the alarm information and issued.

10. A method for controlling a bypass isolation valve in oil product relocation operations according to claim 1, characterized in that: If the primary isolation valve fails to close properly during step S5, then the secondary isolation valve will be closed, a secondary alarm will be issued, and step S6 will be executed. If the secondary isolation valve fails to close properly during step S6, a primary alarm will be issued.

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