Pressure relief system with mechanical interlock, switching method, and dismantling and maintenance method

Abstract

The present invention discloses a pressure relief system with mechanical interlocking, a switching method, and a disassembly and maintenance method. A first isolation valve is provided upstream of a first pressure relief valve. The first isolation valve is provided with a first mechanical logic interlocking device for controlling the on / off of the isolation valve. The first mechanical logic interlocking device has an open position lock hole matching key D and a closed position lock hole matching key C. A third isolation valve is provided upstream of a second pressure relief valve. The third isolation valve is provided with a third mechanical logic interlocking device for controlling the on / off of the isolation valve. The third mechanical logic interlocking device has an open position lock hole matching key B and a closed position lock hole matching key C. The open position lock hole and the closed position lock hole of the same mechanical logic interlocking device are linked to each other. When the open position lock hole or the closed position lock hole locks the matching key, the matching key of the corresponding closed position lock hole or the open position lock hole is released. By setting the mechanical logic lock, the present invention requires operators to perform operations according to the set correct operating sequence, thereby ensuring the safety of the entire operation.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure vessels, pressure-bearing equipment or pressure pipelines, and in particular to a pressure relief system with mechanical interlocking, a switching method and a dismantling and maintenance method. Background Art

[0002] Pressure vessels, pressure-bearing equipment, or pressure pipelines are very common in the petrochemical industry. When the pressure of the medium inside a pressure vessel, pressure-bearing equipment, or pressure pipeline exceeds the specified value, the pressure needs to be discharged to prevent leakage, rupture, explosion, and other serious consequences. Therefore, the design specifications of various related industries all have mandatory requirements for installing pressure relief valves on pressure vessels, pressure-bearing equipment, or pressure pipelines. Pressure relief valves are automatic valves that are normally closed during normal operation. When the pressure exceeds the set value, they automatically open to discharge the medium to reduce the excessive pressure in the container. They are the last safety barrier for the safe operation of pressure vessels, pressure equipment, or pressure pipelines.

[0003] Two sets of pressure relief valves (one working set and one standby set) are required on certain important pressure vessels, pressure-bearing equipment, or pressure pipelines to ensure that the equipment protected by one set of pressure relief valves can be protected by the pressure relief valves when maintenance is required. However, during the pressure relief valve maintenance process, operators need to operate the isolation valves before and after the pressure relief valves to switch between the main and standby pressure relief valves. However, in actual operation, operator error can cause both sets of safety valves to be isolated, which in turn causes various safety accidents of varying degrees. Severe cases can cause overpressure explosions in the protected pressure vessels, pressure-bearing equipment, or pressure pipelines, resulting in personal injury, environmental pollution, property damage, and other accidents. Summary of the Invention

[0004] In response to the above-mentioned problems existing in the prior art, the present invention provides a pressure relief system with mechanical interlocking, a switching method and a dismantling and maintenance method. By adopting redundant pressure relief valves, and providing mechanical logic interlocking devices on the isolation valves upstream and downstream of the pressure relief pipeline, and providing a mechanical logic self-locking device at the connection between the pressure relief valve and the pressure relief pipeline, it is ensured that during the inspection, maintenance and replacement of the pressure relief valve, the pressure vessel, pressure-bearing equipment or pressure pipeline is always in the protection state of the pressure relief valve, and the pressure source can be effectively isolated to maintain safe production.

[0005] The present invention discloses a pressure relief system with mechanical interlock, comprising: a first pressure relief valve and a second pressure relief valve which are arranged on a pressure vessel, pressure-bearing equipment or a pressure pipeline and serve as a primary and a backup for each other;

[0006] A first isolation valve is provided upstream of the first pressure relief valve. The first isolation valve is provided with a first mechanical logic interlocking device for controlling the on / off of the isolation valve. The open position lock hole of the first mechanical logic interlocking device matches key D, and the closed position lock hole matches key C.

[0007] A third isolation valve is provided upstream of the second pressure relief valve. The third isolation valve is provided with a third mechanical logic interlocking device for controlling the on / off of the third isolation valve. The open position lock hole of the third mechanical logic interlocking device matches key B, and the closed position lock hole matches key C.

[0008] The open position lock hole and the closed position lock hole of the same mechanical logic interlocking device are linked together. When the open position lock hole or the closed position lock hole locks a matching key, the matching key of the corresponding closed position lock hole or the open position lock hole is released.

[0009] As a further improvement of the present invention, the present invention further comprises: a status indication key control box placed in the control room, wherein the status indication key control box comprises a first lock hole and a second lock hole;

[0010] The first lock hole matches the key B, and if the key B is inserted, it indicates that the first pressure relief valve is in working state, and if the key B is not inserted, it indicates that the first pressure relief valve is in standby state;

[0011] The second lock hole matches the key D, and the insertion of the key D indicates that the second pressure relief valve is in working state, and the absence of the key D indicates that the second pressure relief valve is in standby state.

[0012] As a further improvement of the present invention,

[0013] When the first pressure relief valve is in operation and the second pressure relief valve is in standby mode:

[0014] When the first isolation valve is opened, the key D is locked in the open position lock hole of the first mechanical logic interlock device, and the key C is released in the closed position lock hole; when the third isolation valve is closed, the key B is released in the open position lock hole of the third mechanical logic interlock device, and the key C is locked in the closed position lock hole; the key B is inserted in the first lock hole of the status indication key control box, and the key D is not inserted in the second lock hole;

[0015] When the first pressure relief valve is in standby mode and the second pressure relief valve is in operation:

[0016] When the first isolation valve is closed, the key D is released from the open position lock hole of the first mechanical logic interlocking device, and the key C is locked in the closed position lock hole; when the third isolation valve is opened, the key B is locked in the open position lock hole of the third mechanical logic interlocking device, and the key C is released from the closed position lock hole; the key B is not inserted in the first lock hole of the status indication key control box, and the key D is inserted in the second lock hole.

[0017] As a further improvement of the present invention,

[0018] A second isolation valve is provided downstream of the first pressure relief valve. The second isolation valve is provided with a second mechanical logic interlocking device for controlling the on / off of the second isolation valve. The open position lock hole of the second mechanical logic interlocking device matches key E, and the closed position lock hole matches key D. A first mechanical logic self-locking device is provided at the connection between the first pressure relief valve and the pressure relief pipeline. The lock hole of the first mechanical logic self-locking device matches key E.

[0019] A fourth isolation valve is provided downstream of the second pressure relief valve, and a fourth mechanical logic interlocking device is provided on the fourth isolation valve for controlling the on and off of the fourth isolation valve. The open position lock hole of the fourth mechanical logic interlocking device matches key A, and the closed position lock hole matches key B; a second mechanical logic self-locking device is provided at the connection between the second pressure relief valve and the pressure relief pipeline, and the lock hole of the second mechanical logic self-locking device matches key A.

[0020] As a further improvement of the present invention, the status indication key control box further includes a third lock hole;

[0021] The third lock hole matches the key C, and the insertion of the key C indicates that the first pressure relief valve and the second pressure relief valve are in working state at the same time.

[0022] As a further improvement of the present invention, it further includes an indicator light that displays the working status of the first pressure relief valve and the second pressure relief valve;

[0023] When key B is inserted into the first lock hole, the working indicator light of the first pressure relief valve lights up;

[0024] When key D is inserted into the second lock hole, the working indicator light of the second pressure relief valve lights up;

[0025] When the key C is inserted into the third lock hole, the indicator lights indicating that the first pressure relief valve and the second pressure relief valve are working simultaneously will light up.

[0026] As a further improvement of the present invention,

[0027] When the first pressure relief valve is in operation and the second pressure relief valve is in standby mode, or when the first pressure relief valve is in standby mode and the second pressure relief valve is in operation:

[0028] When the second isolation valve is opened, key E is locked in the open position lock hole of the second mechanical logic interlocking device, and key D is released in the closed position lock hole, and key E is not inserted in the lock hole of the first mechanical logic self-locking device; when the fourth isolation valve is opened, key A is locked in the open position lock hole of the fourth mechanical logic interlocking device, and key B is released in the closed position lock hole, and key A is not inserted in the lock hole of the second mechanical logic self-locking device.

[0029] The present invention also discloses a pressure relief valve switching method based on the above-mentioned pressure relief system, comprising:

[0030] 1) Switch from the first pressure relief valve working and the second pressure relief valve on standby to the first pressure relief valve working on standby and the second pressure relief valve working:

[0031] Remove key B from the first lock hole of the status indication key control box, insert key B into the open position lock hole of the third mechanical logic interlock device and remove key C from the corresponding closed position lock hole. At this time, the third isolation valve is opened and the second pressure relief valve is in operation; insert key C into the closed position lock hole of the first mechanical logic interlock device and remove key D from the corresponding open position lock hole. At this time, the first isolation valve is closed and the first pressure relief valve is in standby mode; insert key D into the second lock hole of the status indication key control box, indicating that the second pressure relief valve is in operation;

[0032] 2) Switch from the first pressure relief valve in standby mode and the second pressure relief valve in operation to the first pressure relief valve in operation and the second pressure relief valve in standby mode:

[0033] Take out key D from the second lock hole of the status indication key control box, insert key D into the open position lock hole of the first mechanical logic interlocking device and take out key C from the corresponding closed position lock hole. At this time, the first isolation valve is opened and the first pressure relief valve is working; insert key C into the closed position lock hole of the third mechanical logic interlocking device and take out key B from the corresponding open position lock hole. At this time, the third isolation valve is closed and the second pressure relief valve is standby; insert key B into the first lock hole of the status indication key control box, indicating that the first pressure relief valve is in working state.

[0034] As a further improvement of the present invention, it also includes:

[0035] 3) Switch from the first pressure relief valve working and the second pressure relief valve on standby to the first pressure relief valve working and the second pressure relief valve working simultaneously:

[0036] Remove key B from the first lock hole of the status indicator key control box, insert key B into the open position lock hole of the third mechanical logic interlock device, and remove key C from the corresponding closed position lock hole. At this time, the third isolation valve is open and the second pressure relief valve is working; insert key C into the third lock hole of the status indicator key control box, indicating that the first pressure relief valve and the second pressure relief valve are in the working state at the same time;

[0037] 4) Switch from the first pressure relief valve on standby and the second pressure relief valve on working to the first pressure relief valve on working and the second pressure relief valve on working simultaneously:

[0038] Take out key D from the second lock hole of the status indication key control box, insert key D into the open position lock hole of the first mechanical logic interlocking device and take out key C from the corresponding closed position lock hole. At this time, the first isolation valve is opened and the first pressure relief valve is working; insert key C into the third lock hole of the status indication key control box, indicating that the first pressure relief valve and the second pressure relief valve are in working state at the same time.

[0039] The present invention also discloses a method for dismantling and repairing a pressure relief valve based on the above-mentioned pressure relief system, comprising:

[0040] 5) Dismantling and maintenance of the first pressure relief valve:

[0041] Switch the first pressure relief valve to standby mode and the second pressure relief valve to operation mode. Obtain key D released from the open position lock hole of the first mechanical logic interlock device. Insert key D into the closed position lock hole of the second mechanical logic interlock device and remove key E from the corresponding open position lock hole. At this time, the second isolation valve is closed, and the upstream and downstream of the first pressure relief valve are both cut off. Insert key E into the lock hole of the first mechanical logic self-locking device and remove the first pressure relief valve for maintenance.

[0042] 6) Dismantling and maintenance of the second pressure relief valve:

[0043] Switch the first pressure relief valve to working mode and the second pressure relief valve to standby mode, obtain the key B released from the open position lock hole of the third mechanical logic interlocking device; insert the key B into the closed position lock hole of the fourth mechanical logic interlocking device and take out the key A on the corresponding open position lock hole. At this time, the fourth isolation valve is closed and the upstream and downstream of the second pressure relief valve are cut off; insert the key A into the lock hole of the second mechanical logic self-locking device and remove the second pressure relief valve for maintenance.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention ensures inherent safety during safety relief valve switching, inspection, maintenance, or removal operations. It effectively prevents accidents caused by improper operation that could leave pressure vessels, pressure-bearing equipment, or pressure pipelines unprotected. It also effectively isolates upstream and downstream isolation valves during safety relief valve removal for inspection and maintenance. This significantly reduces the risk of personal injury, environmental pollution, and property damage from these operational accidents, ensuring safe and efficient production activities. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The diagram is a structural diagram of a pressure relief system with mechanical interlocking disclosed in one embodiment of the present invention.

[0047] Explanation of symbols:

[0048] 10. First pressure relief valve; 11. First isolation valve; 12. Second isolation valve; 13. First mechanical logic interlocking device; 14. Second mechanical logic interlocking device; 15. First mechanical logic self-locking device;

[0049] 20. Second pressure relief valve; 21. Third isolation valve; 22. Fourth isolation valve; 23. Third mechanical logic interlocking device; 24. Fourth mechanical logic interlocking device; 25. Second mechanical logic self-locking device;

[0050] 30. Status indicator key control box; 31. First lock hole; 32. Second lock hole; 33. Third lock hole;

[0051] 40. Pressure vessels, pressure-bearing equipment or pressure piping;

[0052] Keyhole empty state; Key locked status. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0054] The present invention will be described in further detail below with reference to the accompanying drawings:

[0055] like Figure 1 As shown, the present invention provides a pressure relief system with mechanical interlocking, comprising: a first pressure relief valve 10, a first isolation valve 11, a second isolation valve 12, a first mechanical logic interlocking device 13, a second mechanical logic interlocking device 14, a first mechanical logic self-locking device 15, a second pressure relief valve 20, a third isolation valve 21, a fourth isolation valve 22, a third mechanical logic interlocking device 23, a fourth mechanical logic interlocking device 24, and a second mechanical logic self-locking device 25; wherein,

[0056] The first pressure relief valve 10 (hereinafter referred to as PSV1) and the second pressure relief valve 20 (hereinafter referred to as PSV2) of the present invention are installed in a pressure vessel, pressure-bearing equipment or pressure pipeline 40, and are used to release pressure when the pressure vessel, pressure-bearing equipment or pressure pipeline 40 is overpressured; at the same time, the first pressure relief valve 10 and the second pressure relief valve 20 can serve as a main and backup for each other or work simultaneously when working. The pressure relief valve and the pressure relief pipeline can be installed and connected in a common manner, such as flange connection, threaded connection, welding, etc.

[0057] A first isolation valve (hereinafter referred to as V1) 11 is installed on the upstream pipeline of the first pressure relief valve 10 of the present invention. The first isolation valve 11 is linked to a first mechanical logic interlocking device 13 for controlling the on / off of the isolation valve. The first mechanical logic interlocking device 13 is provided with two lock holes, namely Figure 1 As shown in the figure, the open position lock hole at the top and the closed position lock hole at the bottom, the open position lock hole of the first mechanical logic interlocking device 13 matches the key D, and the closed position lock hole matches the key C; a second isolation valve (hereinafter referred to as V2) 12 is installed on the downstream pipeline of the first pressure relief valve 10, and the second isolation valve 12 is linked with a second mechanical logic interlocking device 14 for controlling the on and off of the isolation valve, the open position lock hole of the second mechanical logic interlocking device 14 matches the key E, and the closed position lock hole matches the key D; a third pressure relief valve 20 of the present invention is installed on the upstream pipeline Isolation valve (hereinafter referred to as V3) 21, the third isolation valve 21 is linked to a third mechanical logic interlock device 23 for controlling the opening and closing of the isolation valve, the open position lock hole of the third mechanical logic interlock device 23 matches key B, and the closed position lock hole matches key C; a fourth isolation valve (hereinafter referred to as V4) 22 is installed on the downstream pipeline of the second pressure relief valve 20, and the fourth isolation valve 22 is linked to a fourth mechanical logic interlock device 24 for controlling the opening and closing of the isolation valve, the open position lock hole matches key A, and the closed position lock hole matches key B. Among them,

[0058] The open lock hole, closed lock hole, lock core and valve core are linked together. The isolation valve can be opened by the key on the open lock hole, and the isolation valve can be closed by the key on the closed lock hole. At the same time, a mechanical limit is set between the lock core and the above-mentioned valve operating handle / valve stem. The lock core machining parts are used to limit the movement / stroke of the corresponding operating handle / valve stem and lock the corresponding key to achieve the following requirements:

[0059] 1. When the valve is open, the open position lock hole locks the matching key, and the closed position lock hole releases the matching key;

[0060] 2. When the valve is closed, the matching key is locked in the closed position lock hole and released in the open position lock hole;

[0061] 3. When the valve is closed, insert the matching key into the open position lock hole to unlock the valve opening stroke, and operate the handle to open the valve;

[0062] 4. When the valve is open, insert the matching key into the closed position lock hole to unlock the valve closing stroke, and operate the handle to close the valve.

[0063] In the present invention, a first mechanical logic self-locking device 15 is provided at the connection between the first pressure relief valve 10 and the pressure relief pipeline, and the lock hole of the first mechanical logic self-locking device 15 matches the key E; a second mechanical logic self-locking device 25 is provided at the connection between the second pressure relief valve 20 and the pressure relief pipeline, and the lock hole of the second mechanical logic self-locking device 25 matches the key A.

[0064] The mechanical logic self-locking device controls the lock core to mechanically restrict the connection between the pressure relief valve and the upstream and downstream pipelines, such as the flange connection, to achieve the following requirements:

[0065] 1. When the pressure relief valve is connected to the upstream and downstream pipelines, release the matching key of the lock hole;

[0066] 2. When the pressure relief valve is removed, the key is locked in the lock hole;

[0067] 3. When the pressure relief valve is connected to the upstream and downstream pipelines, inserting a matching key into the lock hole can unlock the corresponding mechanical limit and remove the corresponding pressure relief valve.

[0068] The status indication key control box 30 of the present invention is placed in the control room, and the status indication key control box 30 includes a first lock hole 31, a second lock hole 32 and a third lock hole 33; wherein, the first lock hole 31 matches the key B, and the insertion of the key B indicates that the first pressure relief valve 10 is in the working state, and the absence of the key B indicates that the first pressure relief valve 10 is in the standby state; the second lock hole 32 matches the key D, and the insertion of the key D indicates that the second pressure relief valve 20 is in the working state, and the absence of the key D indicates that the second pressure relief valve 20 is in the standby state; the third lock hole 33 matches the key C, and the insertion of the key C indicates that the first pressure relief valve 10 and the second pressure relief valve 20 are in the working state at the same time.

[0069] Furthermore, it also includes indicator lights that display the working status of the first pressure relief valve 10 and the second pressure relief valve 20; when the key B is inserted into the first lock hole 31, the working indicator light of the first pressure relief valve 10 is on; when the key D is inserted into the second lock hole 32, the working indicator light of the second pressure relief valve 20 is on; when the key C is inserted into the third lock hole 33, the indicator lights that the first pressure relief valve 10 and the second pressure relief valve 20 are working simultaneously are on.

[0070] Among them, the mechanical logic lock and key involved above adopt the mechanical structure of common locks and keys, and the mechanical limit device adopts the hard limit structure of common machined parts, which are all existing technologies well known to those skilled in the art.

[0071] The pressure relief valve corresponds to two states: working state and standby state;

[0072] When PSV is in working state: both upstream and downstream isolation valves are in open state;

[0073] When the PSV is in standby mode: the upstream isolation valve is closed and the downstream isolation valve is open;

[0074] The pressure relief system is divided into the following two working states according to the status of the redundant pressure relief valves and the need for safe operation:

[0075] 1.PSV1 is working and PSV2 is on standby:

[0076] The upstream and downstream isolation valves V1 and V2 of PSV1 are in the open state, the upstream isolation valve V3 of PSV2 is in the closed state, and the downstream isolation valve V4 of PSV2 is in the open state; at this time, the key D is locked in the open position lock hole of the first mechanical logic interlocking device 13, and the key C is released in the closed position lock hole; the key B is released in the open position lock hole of the third mechanical logic interlocking device 23, and the key C is locked in the closed position lock hole; the key E is locked in the open position lock hole of the second mechanical logic interlocking device 14, and the key D is released in the closed position lock hole, and the key E is not inserted in the lock hole of the first mechanical logic self-locking device 15; the key A is locked in the open position lock hole of the fourth mechanical logic interlocking device 24, and the key B is released in the closed position lock hole, and the key A is not inserted in the lock hole of the second mechanical logic self-locking device 25; the key B is inserted in the first lock hole 31 of the status indication key control box 30, and the key D is not inserted in the second lock hole 32.

[0077] 2.PSV2 is working and PSV1 is on standby:

[0078] The upstream and downstream isolation valves V3 and V4 of PSV2 are in the open state, the upstream isolation valve V1 of PSV1 is in the closed state, and the downstream isolation valve V2 of PSV2 is in the open state; at this time, the key D is released from the open position lock hole of the first mechanical logic interlocking device 13, and the key C is locked in the closed position lock hole; the key B is locked in the open position lock hole of the third mechanical logic interlocking device 23, and the key C is released in the closed position lock hole; the key E is locked in the open position lock hole of the second mechanical logic interlocking device 14, and the key D is released in the closed position lock hole, and the key E is not inserted in the lock hole of the first mechanical logic self-locking device 15; the key A is locked in the open position lock hole of the fourth mechanical logic interlocking device 24, and the key B is released in the closed position lock hole, and the key A is not inserted in the lock hole of the second mechanical logic self-locking device 25; the key B is not inserted in the first lock hole 31 of the status indication key control box 30, and the key D is inserted in the second lock hole 32.

[0079] The present invention provides a method for using the pressure relief system, comprising:

[0080] 1. Switch from the first pressure relief valve 10 working and the second pressure relief valve 20 on standby to the first pressure relief valve 10 on standby and the second pressure relief valve 20 working:

[0081] Take out key B from the first lock hole 31 of the status indication key control box 30, insert key B into the open position lock hole of the third mechanical logic interlocking device 23 and take out key C from the corresponding closed position lock hole. At this time, the third isolation valve 21 is opened and the second pressure relief valve 20 is working; insert key C into the closed position lock hole of the first mechanical logic interlocking device 13 and take out key D from the corresponding open position lock hole. At this time, the first isolation valve 11 is closed and the first pressure relief valve 10 is standby; insert key D into the second lock hole 32 of the status indication key control box 30, indicating that the second pressure relief valve 20 is in working state.

[0082] 2. Switch from the first pressure relief valve 10 being on standby and the second pressure relief valve 20 being in operation to the first pressure relief valve 10 being in operation and the second pressure relief valve 20 being on standby:

[0083] Take out key D from the second lock hole 32 of the status indication key control box 30, insert key D into the open position lock hole of the first mechanical logic interlocking device 13 and take out key C from the corresponding closed position lock hole. At this time, the first isolation valve 11 is opened and the first pressure relief valve 10 is working; insert key C into the closed position lock hole of the third mechanical logic interlocking device 23 and take out key B from the corresponding open position lock hole. At this time, the third isolation valve 21 is closed and the second pressure relief valve 20 is standby; insert key B into the first lock hole 31 of the status indication key control box 30, indicating that the first pressure relief valve 10 is in working state.

[0084] 3. Switch from the first pressure relief valve 10 working and the second pressure relief valve 20 on standby to the first pressure relief valve 10 working and the second pressure relief valve 20 working simultaneously:

[0085] Take out key B from the first lock hole 31 of the status indication key control box 30, insert key B into the open position lock hole of the third mechanical logic interlocking device 23 and take out key C from the corresponding closed position lock hole. At this time, the third isolation valve 21 is opened and the second pressure relief valve 20 is working; insert key C into the third lock hole 33 of the status indication key control box 30, indicating that the first pressure relief valve 10 and the second pressure relief valve 20 are in working state at the same time.

[0086] 4. Switch from the first pressure relief valve 10 being on standby and the second pressure relief valve 20 being in operation to the first pressure relief valve 10 being in operation and the second pressure relief valve 20 being in operation simultaneously:

[0087] Take out the key D from the second lock hole 32 of the status indication key control box 30, insert the key D into the open position lock hole of the first mechanical logic interlocking device 13 and take out the key C from the corresponding closed position lock hole. At this time, the first isolation valve 11 is opened and the first pressure relief valve 10 is working; insert the key C into the third lock hole 33 of the status indication key control box 30, indicating that the first pressure relief valve 10 and the second pressure relief valve 20 are in working state at the same time.

[0088] 5. Dismantling and maintenance of the first pressure relief valve 10:

[0089] According to the above method, switch to the first pressure relief valve 10 as standby and the second pressure relief valve 20 as working, obtain the key D released from the open position lock hole of the first mechanical logic interlocking device 13; insert the key D into the closed position lock hole of the second mechanical logic interlocking device 14 and take out the key E on the corresponding open position lock hole. At this time, the second isolation valve 12 is closed, and the upstream and downstream of the first pressure relief valve 10 are cut off; insert the key E into the lock hole of the first mechanical logic self-locking device 15, and remove the first pressure relief valve 10 for inspection; after the inspection of the first pressure relief valve 10 is completed, reinstall and connect the first pressure relief valve 10, and take out the key E in the self-locking lock hole of the first mechanical logic self-locking device 15; insert the key E into the open position lock hole of the second isolation valve 12, and operate the handle to open the second isolation valve 12, and take out the key D in the corresponding closed position lock hole; insert the key D into the second lock hole 32 of the status indication key control box 30.

[0090] 6. Dismantling and maintenance of the second pressure relief valve 20:

[0091] According to the above method, switch to the working state of the first pressure relief valve 10 and the standby state of the second pressure relief valve 20, and obtain the key B released from the open position lock hole of the third mechanical logic interlocking device 23; insert the key B into the closed position lock hole of the fourth mechanical logic interlocking device 24 and take out the key A on the corresponding open position lock hole. At this time, the fourth isolation valve 22 is closed, and the upstream and downstream of the second pressure relief valve 20 are cut off; insert the key A into the lock hole of the second mechanical logic self-locking device 25, and remove the second pressure relief valve 20 for inspection; after the inspection of the second pressure relief valve 20 is completed, reinstall and connect the second pressure relief valve 20, and take out the key A in the self-locking lock hole of the second mechanical logic self-locking device 25; insert the key A into the open position lock hole of the fourth isolation valve 22, and operate the handle to open the fourth isolation valve 22, and take out the key B in the corresponding closed position lock hole; insert the key B into the first lock hole 31 of the status indication key control box 30.

[0092] The advantages of the present invention are:

[0093] When the protected pressure vessel, pressure-bearing equipment or pressure pipeline is operating normally, one of the redundant pressure relief valves is in working condition, the front and rear isolation valves are in open condition, the other pressure relief valve is in standby condition, the upstream isolation valve is closed, and the downstream isolation valve is open. The pressure relief valve can relieve pressure at any time when the medium in the protected equipment is overpressured; when the operating pressure relief valve needs to be switched to the standby safety relief valve according to the normal inspection and maintenance cycle or when there is a fault and needs inspection, maintenance or even replacement, the operator can only obtain the mechanical logic device status indication key control box from the central control room in the correct and safe operation sequence, take out the key in the corresponding state, and safely operate the corresponding isolation valve and safety valve in turn, thereby ensuring that there is always a pressure relief valve in the pressure relief system in working condition and the standby pressure relief valve is in an effective isolation state, so as to safely carry out the main and standby switching, inspection, maintenance and replacement operations, ensure the safety of personnel, equipment and property, eliminate the risk factors of human operation errors or disregard of safety operating procedures during the operation of the safety valve, and ensure safe production.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A pressure relief system with mechanical interlock, characterized in that: include: A first pressure relief valve and a second pressure relief valve provided on the pressure vessel, pressure-bearing equipment or pressure pipeline and serving as a primary and a secondary pressure relief valve, and a status indication key control box placed in the control room; A first isolation valve is provided upstream of the first pressure relief valve. The first isolation valve is provided with a first mechanical logic interlocking device for controlling the on / off of the isolation valve. The open position lock hole of the first mechanical logic interlocking device matches key D, and the closed position lock hole matches key C. A second isolation valve is provided downstream of the first pressure relief valve. The second isolation valve is provided with a second mechanical logic interlocking device for controlling the on / off of the second isolation valve. The open position lock hole of the second mechanical logic interlocking device matches key E, and the closed position lock hole of the second mechanical logic interlocking device matches key D. A first mechanical logic self-locking device is provided at the connection between the first pressure relief valve and the pressure relief pipeline. The lock hole of the first mechanical logic self-locking device matches key E. A third isolation valve is provided upstream of the second pressure relief valve. The third isolation valve is provided with a third mechanical logic interlocking device for controlling the on / off of the third isolation valve. The open position lock hole of the third mechanical logic interlocking device matches key B, and the closed position lock hole matches key C. A fourth isolation valve is provided downstream of the second pressure relief valve. The fourth isolation valve is provided with a fourth mechanical logic interlocking device for controlling the on / off of the fourth isolation valve. The open position lock hole of the fourth mechanical logic interlocking device matches key A, and the closed position lock hole matches key B. A second mechanical logic self-locking device is provided at the connection between the second pressure relief valve and the pressure relief pipeline. The lock hole of the second mechanical logic self-locking device matches key A. The open position lock hole and the closed position lock hole of the same mechanical logic interlocking device are linked to each other. When the open position lock hole or the closed position lock hole locks the matching key, the matching key of the corresponding closed position lock hole or the open position lock hole is released; The status indication key control box includes a first lock hole, a second lock hole, and a third lock hole. The first lock hole matches key B, and inserting key B indicates that the first pressure relief valve is in working state and the second pressure relief valve is in standby state. The second lock hole matches key D, and inserting key D indicates that the second pressure relief valve is in working state and the first pressure relief valve is in standby state. The third lock hole matches key C, and inserting key C indicates that the first and second pressure relief valves are in working state at the same time. In addition, through the setting of mechanical logic, only one key can be in the status indication key control box at the same time, clearly indicating the current state. When the first pressure relief valve is in operation and the second pressure relief valve is in standby mode: When the first isolation valve is opened, key D is locked in the open position lock hole of the first mechanical logic interlocking device, and key C is released in the closed position lock hole; when the second isolation valve is opened, key E is locked in the open position lock hole of the second mechanical logic interlocking device, and key D is released in the closed position lock hole, and key E is not inserted in the lock hole of the first mechanical logic self-locking device; when the third isolation valve is closed, key B is released in the open position lock hole of the third mechanical logic interlocking device, and key C is locked in the closed position lock hole; when the fourth isolation valve is opened, key A is locked in the open position lock hole of the fourth mechanical logic interlocking device, and key B is released in the closed position lock hole, and key A is not inserted in the lock hole of the second mechanical logic self-locking device; key B is inserted in the first lock hole of the status indication key control box, and no keys are inserted in the second and third lock holes; When the first pressure relief valve is in standby mode and the second pressure relief valve is in operation: When the first isolation valve is closed, key D is released from the open position lock hole of the first mechanical logic interlock device, and key C is locked in the closed position lock hole. When the second isolation valve is opened, key E is locked in the open position lock hole of the second mechanical logic interlock device, and key D is released from the closed position lock hole. Key E is not inserted into the lock hole of the first mechanical logic self-locking device. When the third isolation valve is opened, key B is locked in the open position lock hole of the third mechanical logic interlock device, and key C is released from the closed position lock hole. When the fourth isolation valve is opened, key A is locked in the open position lock hole of the fourth mechanical logic interlock device, and key B is released from the closed position lock hole. Key A is not inserted into the lock hole of the second mechanical logic self-locking device. No key is inserted into the first and third lock holes of the status indication key control box, and key D is inserted into the second lock hole.

2. The pressure relief system with mechanical interlock according to claim 1, characterized in that: The status indication key control box also includes indicator lights that display the working status of the first pressure relief valve and the second pressure relief valve; When key B is inserted into the first lock hole, the working indicator light of the first pressure relief valve lights up; When key D is inserted into the second lock hole, the working indicator light of the second pressure relief valve lights up; When the key C is inserted into the third lock hole, the indicator lights indicating that the first pressure relief valve and the second pressure relief valve are working simultaneously will light up.

3. A switching method for a pressure relief system with mechanical interlock according to any one of claims 1 to 2, characterized in that: include: 1) Switch from the first pressure relief valve working and the second pressure relief valve on standby to the first pressure relief valve working on standby and the second pressure relief valve working: Remove key B from the first lock hole of the status indication key control box, insert key B into the open position lock hole of the third mechanical logic interlock device and remove key C from the corresponding closed position lock hole. At this time, the third isolation valve is opened and the second pressure relief valve is in operation; insert key C into the closed position lock hole of the first mechanical logic interlock device and remove key D from the corresponding open position lock hole. At this time, the first isolation valve is closed and the first pressure relief valve is in standby mode; insert key D into the second lock hole of the status indication key control box, indicating that the second pressure relief valve is in operation; 2) Switch from the first pressure relief valve in standby mode and the second pressure relief valve in operation to the first pressure relief valve in operation and the second pressure relief valve in standby mode: Take out key D from the second lock hole of the status indication key control box, insert key D into the open position lock hole of the first mechanical logic interlocking device and take out key C from the corresponding closed position lock hole. At this time, the first isolation valve is opened and the first pressure relief valve is working; insert key C into the closed position lock hole of the third mechanical logic interlocking device and take out key B from the corresponding open position lock hole. At this time, the third isolation valve is closed and the second pressure relief valve is standby; insert key B into the first lock hole of the status indication key control box, indicating that the first pressure relief valve is in working state.

4. The switching method according to claim 3, wherein: Also includes: 3) Switch from the first pressure relief valve working and the second pressure relief valve on standby to the first pressure relief valve working and the second pressure relief valve working simultaneously: Remove key B from the first lock hole of the status indicator key control box, insert key B into the open position lock hole of the third mechanical logic interlock device, and remove key C from the corresponding closed position lock hole. At this time, the third isolation valve is open and the second pressure relief valve is working; insert key C into the third lock hole of the status indicator key control box, indicating that the first pressure relief valve and the second pressure relief valve are in the working state at the same time; 4) Switch from the first pressure relief valve on standby and the second pressure relief valve on working to the first pressure relief valve on working and the second pressure relief valve on working simultaneously: Take out key D from the second lock hole of the status indication key control box, insert key D into the open position lock hole of the first mechanical logic interlocking device and take out key C from the corresponding closed position lock hole. At this time, the first isolation valve is opened and the first pressure relief valve is working; insert key C into the third lock hole of the status indication key control box, indicating that the first pressure relief valve and the second pressure relief valve are in working state at the same time.

5. A method for dismantling and repairing a pressure relief system with mechanical interlock according to any one of claims 1 to 2, characterized in that: include: 1) Dismantling and maintenance of the first pressure relief valve: Switch the first pressure relief valve to standby and the second pressure relief valve to working mode, obtain key D released from the open position lock hole of the first mechanical logic interlock device; insert key D into the closed position lock hole of the second mechanical logic interlock device and remove key E from the corresponding open position lock hole. At this time, the second isolation valve is closed, and the upstream and downstream of the first pressure relief valve are both cut off; insert key E into the lock hole of the first mechanical logic self-locking device to unlock the first mechanical logic self-locking device and remove the first pressure relief valve for maintenance; 2) Dismantling and maintenance of the second pressure relief valve: Switch the first pressure relief valve to working and the second pressure relief valve to standby, obtain the key B released from the open position lock hole of the third mechanical logic interlocking device; insert the key B into the closed position lock hole of the fourth mechanical logic interlocking device and take out the key A on the corresponding open position lock hole. At this time, the fourth isolation valve is closed and the upstream and downstream of the second pressure relief valve are cut off; insert the key A into the lock hole of the second mechanical logic self-locking device, unlock the second mechanical logic self-locking device, and remove the second pressure relief valve for maintenance.

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