A pressure balance expansion joint for the outlet elbow of a gas turbine

Abstract

The present invention provides a pressure balance expansion joint for the outlet elbow of a gas turbine, which includes a cylinder section assembly, a working bellows, an intermediate pipe, a balance bellows, a tee assembly, a tie rod, an end plate assembly and a lower end pipe. The intermediate pipe is located at the lower part of the cylinder section assembly and is between the upper and lower working bellows, and the intermediate pipe is connected to the two working bellows at both ends. A spring support assembly is arranged at the middle part of the cylinder section assembly, and the spring support assembly is rigidly connected to the tee assembly and the tie rod. The spring support assembly includes a spring, a force sensor and a spring force monitoring system. The spring force monitoring system gives early warnings and reminders according to the spring force condition monitored by the force sensor, realizes the monitoring of the load-bearing spring of the pressure balance expansion joint at the outlet of the gas turbine, enables early warning in time before it fails, effectively avoids accidents, and avoids damage to the gas turbine caused by the damage of the expansion joint.

Description

Technical Field

[0001] The present invention relates to the technical field of expansion joints, and particularly to a pressure balance expansion joint for the outlet elbow of a gas turbine. Background Art

[0002] A gas turbine (abbreviated as GT) is an important energy-saving device in a fluid catalytic cracking unit and other petrochemical plants. Its normal operation is also the key to ensuring the long-term large-load production of the unit system. The technology of the GT is complex, the operating conditions are harsh, and the force requirements on the pipe orifices are extremely demanding. Excessive force on the GT pipe orifices is likely to cause GT failures or malfunctions, posing a great safety hazard. In addition, the equipment is expensive and the maintenance cost is high. The failure or malfunction of the GT will cause huge economic losses to the enterprise. In order to reduce the forces at the inlet and outlet of the GT equipment, a pressure balance expansion joint is often installed in the outlet pipeline to absorb the horizontal displacement of the GT along the axis and the thermal expansion displacement of the vertical pipeline at the GT outlet. Therefore, the safety and reliability of this pressure balance expansion joint play a crucial role in the normal operation of the GT.

[0003] At present, the following main problems exist in the operation of this pressure balance expansion joint: (1) This pressure balance expansion joint is often heavy, seriously exceeding the force limit of the GT pipe orifice. Usually, a load-bearing spring is set to bear the self-weight of the expansion joint at the GT outlet and other additional weights, so as to reduce the influence of the self-weight of the expansion joint and other additional weights on the force of the GT pipe orifice. Since the medium temperature at the GT outlet is relatively high, the spring works at high temperature for a long time and needs to bear a load of dozens of tons. Under long-term working conditions, the spring is prone to relaxation, unable to fully bear the self-weight of the expansion joint and other additional weights, or the spring cannot work properly due to other failures, and the GT pipe orifice will bear a huge load, resulting in GT failures or malfunctions. (2) It is impossible to predict in advance before the bellows leaks and fails, and it is impossible to make preparations in advance, affecting the long-term reliable operation of the unit. (3) The medium flow rate at the GT outlet pipeline is high. If the flow guide cylinder of the expansion joint is not properly set, it is easy to cause detachment, resulting in damage to the GT equipment and bringing huge losses. (4) The structural parts are not properly designed or in a high-stress state, resulting in creep failure of the weld after long-term high-temperature service; (5) The stability of the intermediate pipe between the two groups of working bellows is insufficient and the vibration is relatively severe. Therefore, it is necessary to invent a new pressure balance expansion joint for the outlet elbow of a gas turbine to effectively solve the above problems, realize the timely warning before the failure of important components of the expansion joint, and improve the anti-vibration performance of the product. Summary of the Invention

[0004] In view of this, the present invention aims to provide a pressure balance expansion joint for the outlet elbow of a gas turbine to solve the problems in the prior art that it is impossible to give a timely warning before the failure of important components of the expansion joint and the anti-vibration performance of the expansion joint is weak.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] A pressure balance expansion joint for the outlet elbow of a gas turbine, comprising a cylinder section assembly, a working bellows, an intermediate pipe, a balance bellows, a tee assembly, a tie rod, an end plate assembly and a lower end pipe. The intermediate pipe is located at the lower part of the cylinder section assembly, between two upper and lower working bellows, and the intermediate pipe connects the two working bellows at both ends. A spring support assembly is arranged at the middle part of the cylinder section assembly, and the spring support assembly is rigidly connected to the tee assembly and the tie rod. The spring support assembly includes a spring, a force sensor and a spring force monitoring system. The spring force monitoring system gives an early warning and reminder according to the spring force condition monitored by the force sensor. A spring force threshold F0 is set in the spring force monitoring system, and the spring force is F.

[0007] When 0.75F0 ≤ F < F0, the spring force monitoring system gives a reminder;

[0008] When F < 0.75F0, the spring force monitoring system automatically gives an alarm.

[0009] Further, the spring support assembly further includes a suspension plate assembly. The suspension plate assembly includes an upper suspension plate and a lower suspension plate. The upper end of the spring is connected to the upper suspension plate, and the upper suspension plate is rigidly connected to the tee assembly. The lower end of the spring is connected to the lower suspension plate through the force sensor, and the lower suspension plate is rigidly connected to the tie rod.

[0010] Further, the end plate assembly is connected to the lower working bellows. A universal joint ring and a proportional link are arranged between the upper and lower two groups of working bellows. The universal joint ring is arranged on the intermediate pipe, and the universal joint ring is connected to the intermediate pipe through a saddle assembly.

[0011] Further, saddles are arranged at the top, middle part and lower end of the universal joint ring. The middle part of the proportional link is connected to the universal joint ring through the middle saddle, and the lower end of the proportional link is connected to the lower end pipe through the lower saddle.

[0012] Further, a flow guide cylinder is also arranged inside the cylinder section assembly, and the flow guide cylinder and the cylinder section assembly are welded in a fillet weld form.

[0013] Further, plug weld holes are evenly arranged on the circumference of the straight edge section of the flow guide cylinder, and the inclined edge and the straight edge of the flow guide cylinder are integrally formed.

[0014] Further, a first ring plate assembly is also provided at a position near the top of the barrel section assembly. The first ring plate assembly adopts a floating design. A gap is provided between the bottom plate of the first ring plate assembly and the barrel section assembly. A second ring plate assembly is provided on the outer side of the lower end pipe. The second ring plate assembly also adopts a floating design. A gap is provided between the bottom of the second ring plate assembly and the outer wall of the lower end pipe.

[0015] Further, a vibration damping device is provided at the intermediate pipe. The vibration damping device includes an eddy current damper and a clamp. The eddy current damper is connected to the intermediate pipe through the clamp.

[0016] Further, alarm components are provided for all the working bellows of the gas turbine. When leakage occurs inside or outside the bellows, the alarm components can give early warnings in a timely manner according to the monitored pressure changes.

[0017] Compared with the prior art, the pressure balance expansion joint of the gas turbine outlet bend of the present invention has the following advantages:

[0018] Through the spring support assembly, the monitoring of the load-bearing springs of the pressure balance expansion joint at the outlet of the gas turbine is realized, solving the problem that the springs of the existing expansion joints at the outlet of the gas turbine cannot give early warnings in time before failure, effectively avoiding accidents, being beneficial to the long-term safe and reliable operation of the product, and avoiding damage to the gas turbine caused by the damage of the expansion joint.

[0019] A universal joint ring is provided on the intermediate pipe. The universal joint ring is connected to the intermediate pipe through a saddle assembly and is also connected to the proportional link between the two groups of bellows, forming a universal proportional link assembly, which can not only balance the displacements of the two groups of working bellows, avoid excessive deformation of a certain wave caused by uneven displacements, but also improve the stability of the intermediate pipe, reduce the vibration of the intermediate pipe, and improve the anti-vibration performance of the expansion joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the balance expansion joint according to Embodiment 1 of the present invention;

[0021] Figure 2 is a schematic structural diagram of the balance expansion joint according to Embodiment 2 of the present invention.

[0022] DESCRIPTION OF THE REFERENCE NUMERALS:

[0023] 1 - Cylinder section assembly, 2 - First ring plate assembly, 3 - Balancing bellows, 4 - Flow guide cylinder, 5 - Alarm assembly, 61 - Upper suspension plate, 62 - Lower suspension plate, 7 - Tee assembly, 8 - Spring, 9 - Force sensor, 10 - Spring force monitoring system, 11 - Working bellows, 12 - Proportional link, 13 - Saddle assembly, 14 - Universal ring, 15 - Intermediate pipe, 16 - Tie rod, 17 - End plate assembly, 18 - Vibration damping device, 19 - Lower end pipe, 20 - Head, 21 - Eddy current damper Detailed implementation manners

[0024] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings. Among them, the term "connection" can be a direct connection or an indirect connection, and the term "on..." means directly supported by... elements, or indirectly supported by the element through another element integrated into or supported by the element.

[0025] A pressure - balanced expansion joint structure for the outlet elbow of a gas turbine, comprising a head 20, a cylinder section assembly 1, a working bellows 11, an intermediate pipe 15, a balancing bellows 3, a tee assembly 7, a tie rod 16, an end plate assembly 17 and a lower end pipe 19. The head 20 is located at the top of the cylinder section assembly 1, and the intermediate pipe 15 is located at the lower part of the cylinder section assembly 1. Among them, the intermediate pipe 15 is located between two working bellows 11 up and down, and the intermediate pipe 15 connects the two working bellows 11 at both ends. The balancing bellows 3 is located at a position near the upper part of the cylinder section assembly 1, and the outlet pipe of the gas turbine is connected to the end plate assembly 17 of the elbow pressure - balanced expansion joint through a connecting piece. A spring support assembly is arranged in the middle part of the cylinder section assembly 1. The spring support assembly is rigidly connected to the tee assembly 7 and the tie rod 16. The spring support assembly includes a spring 8, a force sensor 9 and a spring force monitoring system 10. The spring force monitoring system 10 gives an early warning and reminder according to the force condition of the spring 8 monitored by the force sensor 9. Through the improvement of the spring support assembly, it can realize the self - load - bearing function and at the same time can monitor the force of the spring. A force - measuring element and a force - monitoring alarm system are added to the traditional spring assembly, which can judge and give an early warning to the force state of the load - bearing spring. When the spring cannot bear the load due to relaxation or failure, an early warning is given in time, so that the failure can be dealt with in time to avoid damage to the gas turbine equipment caused by the spring failure.

[0026] Furthermore, the spring support assembly further includes a suspension plate assembly. The upper end of the spring 8 is connected to the upper suspension plate 61, and the upper suspension plate 61 is rigidly connected to the tee assembly 7. The lower end of the spring 8 is connected to the lower suspension plate 62 through the force sensor 9, and the lower suspension plate 62 is rigidly connected to the tie rod 16. Among them, the upper end of the spring 8 can also be connected to the fixed foundation of the expansion joint through other structures. The fixed foundation of the expansion joint can be a cement pier or a steel structure fixed on the ground or the workbench surface, etc.

[0027] Furthermore, the end plate assembly 17 is connected to the lower working bellows 11. A universal joint ring 14 and a proportional link 12 assembly are arranged between the upper and lower groups of working bellows 11. The universal joint ring 14 is arranged on the intermediate pipe 15, and the universal joint ring 14 is connected to the intermediate pipe 15 through a saddle assembly 13. A universal proportional link assembly is formed, which can not only balance the displacements of the two groups of working bellows, avoid excessive deformation of a local wave caused by uneven displacements, but also improve the stability of the intermediate pipe 15 and reduce the vibration of the intermediate pipe. Compared with a single proportional link assembly, it has better displacement coordination, and at the same time allows the two groups of bellows assemblies to generate lateral displacements in two planes, and has a better displacement compensation function.

[0028] Furthermore, saddles are arranged at the top, middle and lower ends of the universal joint ring 14. The middle part of the proportional link 12 is connected to the universal joint ring 14 through the middle saddle, and the lower end of the proportional link 12 is connected to the lower pipe 19 through the lower saddle.

[0029] As one embodiment of the present invention, a flow guide cylinder 4 is further arranged inside the cylinder section assembly 1. The flow guide cylinder 4 and the cylinder section assembly 1 are welded by fillet welds. At the same time, evenly distributed plug weld holes are opened on the circumference of the straight edge section of the flow guide cylinder, which enhances the connection strength between the flow guide cylinder and the cylinder section and avoids damage to the fan caused by the detachment of the flow guide cylinder. The inclined side and the straight side of the flow guide cylinder are integrally formed. This ensures a smooth transition and can reduce the resistance when the medium flows through. The flow guide cylinder adopts the structure of fillet welds and plug weld holes, replacing the previous gasket ring structure, which can improve the connection strength between the flow guide cylinder and the end pipe, avoid damage to the equipment caused by the detachment of the flow guide cylinder, and at the same time, the flow resistance of the new structure is smaller than that of the gasket ring structure, reducing the erosion of the medium on the flow guide cylinder.

[0030] A first ring plate assembly 2 is also arranged at a position near the top of the cylinder section assembly 1. The first ring plate assembly 2 adopts a floating design. The first ring plate assembly is not directly welded to the cylinder section assembly, and there is a certain gap between the bottom plate of the first ring plate assembly and the cylinder section assembly. This reduces the thermal stress of the first ring plate assembly, improves the stress safety margin of the first ring plate assembly under high-temperature working conditions, and improves the service life of the structural parts and welds of the first ring plate assembly. At the same time, the floating design of the first ring plate assembly separates the first ring plate assembly from the cylinder body, making it not easy to transmit vibration and avoiding the resonance problem when the pipeline vibrates.

[0031] A second ring plate assembly is arranged on the outer side of the lower pipe 19. The second ring plate assembly also adopts a floating design, and a gap is arranged between the bottom of the second ring plate assembly and the outer wall of the lower pipe 19. The floating design of the second ring plate assembly separates the second ring plate assembly from the lower pipe 19, making it not easy to transmit vibration, playing a role in fixing the lower part of the expansion joint, and avoiding the resonance problem when the pipeline vibrates.

[0032] Further, the outlet pipe orifice of the gas turbine is generally set to be square, and the square outlet pipe orifice is connected to the end plate assembly 17 of the elbow pressure balance type expansion joint through a square-to-round connecting piece.

[0033] Further, the bellows adopts a double-layer alarm design, and can give an early warning in time when the inner or outer bellows leaks and fails, so as to avoid affecting the operation of the device when the whole bellows fails.

[0034] Alarm components are arranged on both of the two working bellows 11 of the gas turbine. When the inner or outer side of the working bellows 11 leaks, the alarm components can give an early warning in time according to the monitored pressure change.

[0035] Embodiment 1

[0036] As Figure 1 shown, this embodiment provides a structure of an elbow pressure balance expansion joint at the outlet of a gas turbine, which includes a head 20, a cylinder section assembly 1, a working bellows 11, an intermediate pipe 15, a balance bellows 3, a tee assembly 7, a tie rod 16, and an end plate assembly 17. The head 20 is located at the top of the cylinder section assembly 1, and the intermediate pipe 15 is located at the lower part of the cylinder section assembly 1. Among them, the intermediate pipe 15 is located between the upper and lower working bellows 11, and the intermediate pipe 15 is connected to the two working bellows 11 at both ends. The balance bellows 3 is located at a position close to the upper part of the cylinder section assembly 1, and the gas turbine outlet pipe orifice is connected to the end plate assembly 17 of the elbow pressure balance type expansion joint through a connecting piece.

[0037] The end plate assembly 17 is connected to the lower working bellows 11, and a universal joint 14 and a proportional link 12 assembly are arranged between the upper and lower groups of working bellows 11. The universal joint 14 is arranged on the intermediate pipe 15, and the universal joint 14 is connected to the intermediate pipe 15 through a saddle assembly 13. The proportional link 12 assembly is respectively connected to the lower end pipe 19 and the universal joint 14 through saddles.

[0038] The expansion joint in this embodiment further includes a spring support assembly. The spring support assembly includes a spring 8, a suspension plate assembly, a force sensor 9, and a spring force monitoring system 10. The upper end of the spring 8 is connected to the upper suspension plate 61, and the upper suspension plate 61 is rigidly connected to the tee assembly 7. The lower end of the spring 8 is connected to the lower suspension plate 62 through the force sensor 9, and the lower suspension plate 62 is rigidly connected to the tie rod 16. Or through an additional gravity lifting structure, the upper end of the spring 8 is connected to the fixed foundation of the expansion joint through other structures, the lower end of the spring 8 is connected to the lower suspension plate 62 through the force sensor 9, and the lower suspension plate 62 is rigidly connected to the tie rod 16. It is realized to transfer the weights of structures such as the head 20 and the tie rod 16 to the fixed foundation of the expansion joint. A load-bearing lug is welded on the tee assembly 7 of the expansion joint, and the load-bearing lug is connected to the load-bearing frame through fasteners, and the load-bearing frame is rigidly connected to the fixed foundation of the expansion joint.

[0039] The draft tube 4 and the cylinder section assembly 1 are welded by fillet welds. At the same time, evenly distributed plug weld holes are opened on the circumference of the straight edge section of the draft tube. The inclined side and the straight edge of the draft tube are integrally formed.

[0040] The first ring plate assembly 2 adopts a floating design. The first ring plate assembly is not directly welded to the cylinder section assembly, and a gap is provided between the bottom plate of the first ring plate assembly and the cylinder section assembly.

[0041] The universal joint ring 14 and the proportional link 12 are connected through the saddle assembly 13, and the weight of the intermediate pipe 15 can be transmitted to both ends. The middle part of the proportional link 12 is connected to the universal joint ring 14 through the middle saddle assembly 13, and the lower end of the proportional link 12 is connected to the lower end pipe 19 through the lower saddle assembly 13.

[0042] Embodiment 2:

[0043] As Figure 2 shown, other structures are the same as those in Solution 1. In order to reduce the vibration of the intermediate pipe, a vibration damping device 18 is provided at the intermediate pipe 15. The vibration damping device 18 includes an eddy current damper 21 and a clamp. The eddy current damper 21 is connected to the intermediate pipe 15 through the clamp. When the intermediate pipe 15 vibrates, a damping force is generated through the principle of electromagnetic induction, thereby suppressing or reducing the vibration of the intermediate pipe, and at the same time, the vibration of the pipeline can also be reduced to a certain extent.

[0044] Embodiment 3

[0045] This embodiment provides a method for detecting the failure warning of an expansion joint. The device of Embodiment 1 or Embodiment 2 can be used, and on the basis of the above embodiments, a spring force threshold F0 is set in the spring force monitoring system. The force threshold F is set according to the tensile force borne by the spring and the initial performance of the expansion joint.

[0046] When the equipment is in the installed or operating state, the weight of the expansion joint tee assembly 7 directly acts on the expansion joint fixed foundation. The gravity of parts such as the head 20 and the tie rod 16 is transferred to the expansion joint fixed foundation through self-supporting springs or other gravity lifting structures. At this time, the spring 8 bears a large tensile force.

[0047] When the self-supporting spring or other gravity lifting structures can work normally, the system does not make any treatment.

[0048] When the service life gradually increases, the spring or other load-bearing structures undergo stress relaxation, or the load-bearing components fail, and the weight of some structures is applied to the outlet pipe orifice of the gas turbine. The spring force F will gradually decrease. When 0.75F0 ≤ F < F0, the system will automatically send a feedback message to remind the staff.

[0049] If the load-bearing component fails due to a fault and the spring load-bearing capacity decreases significantly, when F < 0.75F0, the system will activate an audible and visual alarm to prompt the staff to take timely measures to ensure the safety of the equipment.

[0050] The alarm component in this embodiment includes a pressure gauge, a valve, a connecting pipe, etc. The monitoring connecting pipe is connected to the straight edge section of the bellows, and the communication with the bellows layer is achieved by drilling holes in the straight edge section of the bellows. Inert gas is filled between the layers. When leakage occurs in the inner or outer layer of the bellows, the value of the pressure gauge in the alarm component is used to determine whether leakage has occurred, so as to provide reliable information for the device inspection personnel in a timely manner, and the preparation of spare parts can be carried out in a timely manner without affecting the operation of the device.

[0051] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A pressure balance expansion joint for the outlet elbow of a gas turbine, comprising a shell section assembly (1), a working bellows (11), an intermediate pipe (15), a balance bellows (3), a tee assembly (7), a tie rod (16), an end plate assembly (17) and a lower end pipe (19). The intermediate pipe (15) is located at the lower part of the shell section assembly (1), the intermediate pipe (15) is located between two upper and lower working bellows (11), and the intermediate pipe (15) is connected to the two working bellows (11) at both ends. It is characterized in that, A spring support assembly is arranged at the middle part of the shell section assembly (1). The spring support assembly is rigidly connected to the three-way assembly (7) and the tie rod (16). The spring support assembly includes a spring (8), a force sensor (9) and a spring force monitoring system (10). The spring force monitoring system (10) gives an early warning and reminder according to the force condition of the spring (8) monitored by the force sensor (9). A spring force threshold value F0 and a spring force F are set in the spring force monitoring system. When 0.75F0 ≤ F < F0, the spring force monitoring system (10) gives a reminder. When F < 0.75F0, the spring force monitoring system (10) automatically gives an alarm. A flow guide cylinder (4) is also arranged inside the shell section assembly (1). The flow guide cylinder (4) and the shell section assembly (1) are welded in a fillet weld form. A vibration damping device (18) is arranged at the middle pipe (15). The vibration damping device (18) includes an eddy current damper and a clamp. The eddy current damper is connected to the middle pipe (15) through the clamp.

2. The pressure balance expansion joint according to claim 1, wherein The spring support assembly further includes a hanging plate assembly. The hanging plate assembly includes an upper hanging plate (61) and a lower hanging plate (62). The upper end of the spring (8) is connected to the upper hanging plate (61). The upper hanging plate (61) is rigidly connected to the three-way assembly (7). The lower end of the spring (8) is connected to the lower hanging plate (62) through the force sensor (9). The lower hanging plate (62) is rigidly connected to the tie rod (16).

3. The pressure balance expansion joint according to claim 1, characterized in that, The end plate assembly (17) is connected to the lower working bellows (11). A universal joint ring (14) and a proportional link (12) are arranged between the upper and lower groups of the working bellows (11). The universal joint ring (14) is arranged on the middle pipe (15). The universal joint ring (14) is connected to the middle pipe (15) through a saddle assembly (13).

4. The pressure balance expansion joint according to claim 3, wherein Saddles are arranged at the top, middle part and lower end of the universal joint ring (14). The middle part of the proportional link (12) is connected to the universal joint ring (14) through the middle saddle. The lower end of the proportional link (12) is connected to the lower end pipe (19) through the lower saddle.

5. The pressure balance expansion joint according to claim 1, characterized in that, Plug weld holes are evenly arranged on the circumference of the straight edge section of the flow guide cylinder (4). The inclined edge and the straight edge of the flow guide cylinder (4) are integrally formed.

6. The pressure balance expansion joint according to claim 1, characterized in that, A first ring plate assembly (2) is also arranged at the position close to the top of the shell section assembly (1). The first ring plate assembly (2) adopts a floating design. A gap is arranged between the bottom plate of the first ring plate assembly (2) and the shell section assembly (1). A second ring plate assembly is arranged on the outer side of the lower end pipe (19). The second ring plate assembly also adopts a floating design. A gap is arranged between the bottom of the second ring plate assembly and the outer wall of the lower end pipe (19).

7. The pressure balance expansion joint according to claim 1, characterized in that, Alarm components are arranged on the working bellows (11) of the gas turbine. When leakage occurs inside or outside the working bellows (11), the alarm components can give an early warning in time according to the monitored pressure change.

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