A steam turbine anti-leakage high-low pressure bypass valve
Patent Information
- Application Number
- CN202522268656.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-27
- Publication Date
- 2026-08-21
- Estimated Expiration
- 2035-10-27
AI Technical Summary
[0003]然而，高低压旁路阀在机组带负荷后的正常运行阶段，需严密关闭，一旦出现阀门磨损、结垢、执行机构故障或关闭不严等情况，将导致阀门在关闭位置有蒸汽泄漏，即出现“内漏”，“内漏”一，会造成直接能量损失，降低热经济性；使凝汽器和再热器热负荷增加，真空下降；若喷水减温装置的减温水调节不当，未完全蒸发的减温水进入热井，会增大过冷度，导致含氧量超标，凝结水水质恶化，加剧设备腐蚀，再热器超温；二，会对凝汽器产生直接热冲击与破坏，威胁高低压旁路阀及低压缸末级叶片安全，降低机组主保护可靠性；三、会影响机组正常启动，因真空受影响而延误启动时间，还会增加运行调整难度
[0012]By employing the above structure, this utility model adds a sealing gasket at the bottom of the valve seat ring and the inner conical surface of the valve body, thereby forming an elastic seal between the valve seat ring and the valve body. Simultaneously, the multi-compression structure of this device ensures a sealed connection between the valve seat ring and the valve body. The multi-compression structure includes: first, a pressure ring threaded onto the valve body; tightening the pressure ring compresses the valve seat ring and valve body, causing the sealing gasket to deform and fit tightly; second, tightening a specially designed compression bolt on the pressure ring, utilizing a pre-compression spring on the bolt. After tightening the bolt, the bottom of the pre-compression spring abuts against the valve seat ring, providing a pre-compression force to the valve seat ring, further ensuring that the valve seat ring and valve body are always tightly compressed, guaranteeing a tight and leak-free contact between the valve seat and valve body.
Smart Images
Figure CN224665302U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a high and low pressure bypass valve for preventing leakage in steam turbines. Background Technology
[0002] In modern large steam turbine units, high-pressure bypass and low-pressure bypass systems are commonly installed on the main reheat steam pipeline to achieve rapid start-up and shutdown as well as safe and stable operation. The high-pressure bypass system connects the boiler superheater outlet and reheater inlet, while the low-pressure bypass system connects the reheater outlet (i.e., before the intermediate pressure cylinder inlet) to the condenser. The high-pressure bypass valve and low-pressure bypass valve are the core equipment.
[0003] However, during the normal operation phase after the unit is under load, the high and low pressure bypass valves must be tightly closed. If valve wear, scaling, actuator malfunction, or incomplete closure occurs, steam leakage will occur in the closed position, resulting in "internal leakage." Internal leakage has several consequences: First, it causes direct energy loss, reducing thermal efficiency; it increases the heat load on the condenser and reheater, leading to a decrease in vacuum; if the desuperheating water in the spray desuperheating device is improperly adjusted, incompletely evaporated desuperheating water will enter the hot well, increasing subcooling, leading to excessive oxygen content, deterioration of condensate water quality, exacerbating equipment corrosion, and causing reheater overheating. Second, it can cause direct thermal shock and damage to the condenser, threatening the safety of the high and low pressure bypass valves and the last stage blades of the low-pressure cylinder, reducing the reliability of the unit's main protection system. Third, it can affect the normal start-up of the unit, delaying start-up time due to vacuum issues and increasing the difficulty of operational adjustments.
[0004] like Figure 1 As shown, existing high-pressure bypass valves and low-pressure bypass valves have the same structure, mainly composed of valve body 1, valve seat ring 2, pressure ring 3, valve seat sealing surface 5, valve core sealing surface 6, valve stem 8, and electric actuator. Under the closing force of the electric actuator, the valve stem compresses the cup-shaped spring downwards, causing the valve core sealing surface to contact the valve seat sealing surface. After the valve seat sealing surfaces are in contact, the steam inlet is cut off. Internal leakage in the valve is generally caused by defects such as through-flow erosion, scratches, corrosion, cavitation, and cracks on the valve core or valve seat sealing surfaces at valve seat sealing surface 5 and valve core sealing surface 6. Therefore, the direction for existing design or improvement should be... Most considerations focus on reducing wear on the valve seat sealing surface 5 and the valve core sealing surface 6 to improve their sealing reliability, or on facilitating the replacement of the valve seat sealing surface 5 and the valve core sealing surface 6 to improve maintenance efficiency. However, to facilitate the replacement of the sealing surfaces, the valve seat of the high and low pressure bypass valve needs to adopt a detachable structure. This results in a rigid hard seal between the valve seat boss and the inner conical surface of the valve body. After long-term high-temperature operation of the valve, the thermal stress of the locking ring 3 and the clamping bolt 4 of the valve seat will relax, causing the hard seal to fail. This will lead to the inlet steam flow leaking along the boss to A→C or A→B→D, causing steam to leak to the outlet side. Utility Model Content
[0005] This utility model addresses the shortcomings of existing technologies by providing an optimized connection and fit between the pressure ring, valve seat ring, and valve body, thereby eliminating leakage between the valve seat and valve body. It is a high and low pressure bypass valve for steam turbines designed to prevent leakage.
[0006] To achieve the first objective mentioned above, this utility model proposes a high and low pressure bypass valve for steam turbine leakage prevention, comprising a valve body, a valve seat ring, and a pressure ring. The valve seat ring is installed inside the inlet end of the valve body, and a through hole in the middle of the valve seat ring forms the steam inlet hole of the valve body. A boss is provided at the bottom of the valve seat ring. The boss at the bottom of the valve seat ring is sealed to the inner conical surface of the valve body via a sealing gasket. The sealing gasket is sized to match the inner conical surface of the valve body. The side of the sealing gasket facing the boss of the valve seat ring has a groove matching the position and size of the boss, while the other side of the sealing gasket is a plane matching the conical surface of the valve body. In the assembled state, the boss of the valve seat ring is engaged in the groove of the sealing gasket. The valve seat ring is fixed to the valve body by a pressure ring, which is detachably connected to the valve body. The pressure ring compresses the valve seat ring and the valve body, causing the sealing gasket to deform and fit tightly against the valve seat ring and the valve body to achieve a seal. Furthermore, the pressure ring and the valve body are threaded together.
[0007] In this embodiment, the sealing gasket is a nickel mesh graphite gasket.
[0008] In this embodiment, the pressure ring has an external thread, and the inner wall of the valve body has an internal thread that matches the external thread. The outer side of the top surface of the valve seat ring has a clamping groove that matches the size of the pressure ring. The outer side of the pressure ring is threadedly connected to the internal thread of the valve body. The inner side of the pressure ring is slidably connected to the inner wall of the clamping groove. The bottom surface of the pressure ring abuts against the bottom surface of the clamping groove, thereby clamping the valve seat ring by the pressure ring.
[0009] In this embodiment, multiple threaded through holes are evenly distributed on the pressure ring with the steam inlet hole as the center, and a clamping bolt is threaded into the threaded through hole of the pressure ring.
[0010] In this embodiment, the clamping bolt includes a head, a screw, and a preload spring. The screw includes a threaded section that matches the size of the threaded through hole and a guide rod section coaxially connected to the threaded section with an outer diameter smaller than the threaded through hole. The head is fixed on the threaded section, and the preload spring is fitted on the guide rod section. In the assembled state, the clamping bolt is threadedly installed in the threaded through hole, one end of the preload spring presses against the bottom of the threaded section, and the other end abuts against the bottom of the valve seat ring clamping groove.
[0011] In this embodiment, the clamping bolt is an M16 bolt, and the guide rod section is a smooth rod with a length of 15mm and a diameter of Φ8.
[0012] By employing the above structure, this utility model adds a sealing gasket at the bottom of the valve seat ring and the inner conical surface of the valve body, thereby forming an elastic seal between the valve seat ring and the valve body. Simultaneously, the multi-compression structure of this device ensures a sealed connection between the valve seat ring and the valve body. The multi-compression structure includes: first, a pressure ring threaded onto the valve body; tightening the pressure ring compresses the valve seat ring and valve body, causing the sealing gasket to deform and fit tightly; second, tightening a specially designed compression bolt on the pressure ring, utilizing a pre-compression spring on the bolt. After tightening the bolt, the bottom of the pre-compression spring abuts against the valve seat ring, providing a pre-compression force to the valve seat ring, further ensuring that the valve seat ring and valve body are always tightly compressed, guaranteeing a tight and leak-free contact between the valve seat and valve body. Attached Figure Description
[0013] Figure 1 This is a structural diagram of existing high-pressure and low-pressure bypass valves.
[0014] Figure 2 This is a schematic diagram of the structure of this utility model.
[0015] In the attached diagram: 1. Valve body; 2. Valve seat ring; 3. Pressure ring; 4. Clamping bolt; 5. Valve seat sealing surface; 6. Valve core sealing surface; 7. Preload spring; 8. Valve stem; 9. Boss; 10. Sealing gasket. Detailed Implementation
[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0017] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.
[0018] like Figure 2As shown, a high and low pressure bypass valve for preventing leakage in a steam turbine includes a valve body 1, a valve seat ring 2, and a pressure ring 3. The valve seat ring 2 is coaxially mounted inside the inlet end of the valve body 1. A through hole is provided in the middle of the valve seat ring 2 to form the steam inlet hole of the valve body 1. The valve seat ring 2 has an inverted conical valve seat sealing surface 5 on the inner wall of the steam inlet hole outlet. A valve stem 8 is also provided inside the valve body 1, coaxially arranged with the steam inlet hole. A valve core is provided at the bottom of the valve stem 8. The contact surface between the valve core and the valve seat sealing surface 5 is the valve core sealing surface 6. The valve core sealing surface 6 matches the valve seat sealing surface 5. The bottom of the valve seat ring 2... The valve seat ring 2 has a boss 9. The boss 9 at the bottom of the valve seat ring 2 is sealed to the inner conical surface of the valve body 1 by a sealing gasket 10. The sealing gasket 10 is matched to the size of the inner conical surface of the valve body 1. The sealing gasket 10 has a groove on the side facing the boss 9 of the valve seat ring 2 that matches the position and size of the boss 9. The other side of the sealing gasket 10 is a plane that matches the conical surface of the valve body 1. In the assembled state, the boss 9 of the valve seat ring 2 is fitted into the groove of the sealing gasket 10. Furthermore, the sealing gasket 10 is made of a high temperature and high pressure resistant material. Preferably, the sealing gasket 10 is a nickel mesh graphite gasket.
[0019] The valve seat ring 2 is fixed inside the valve body 1 by a pressure ring 3. The pressure ring 3 is provided with an external thread, and the inner wall of the valve body 1 is provided with an internal thread that matches the external thread. The outer side of the top surface of the valve seat ring 2 is provided with a clamping groove that matches the size of the pressure ring 3. After the valve seat ring 2 is installed inside the valve body 1, the outer side of the pressure ring 3 is threadedly connected to the internal thread of the valve body 1. The inner side of the pressure ring 3 is slidably connected to the inner wall of the clamping groove, and the bottom surface of the pressure ring 3 abuts against the bottom surface of the clamping groove, thereby clamping the valve seat ring 2 by the pressure ring 3.
[0020] Multiple threaded through holes are evenly distributed on the pressure ring 3, centered on the steam inlet hole. These threaded through holes are parallel to the steam inlet hole. A clamping bolt 4 is threaded into each of the threaded through holes of the pressure ring 3. The clamping bolt 4 includes a head, a screw, and a preload spring 7. The screw includes a threaded section matching the size of the threaded through hole and a guide section coaxially connected to the threaded section, with an outer diameter smaller than the threaded through hole. The head is fixed to the threaded section, and the preload spring 7 is fitted onto the guide section. One end of the preload spring 7 is fixed to the guide section, and the other end is a free end. The initial length of the preload spring ensures that after the clamping bolt 4 is tightened inside the threaded through hole, the free end of the preload spring extends out of the threaded through hole. The length of the free end of the compression spring extending out of the threaded through hole can be designed according to different usage conditions. In the assembled state, the clamping bolt 4 is threadedly installed in the threaded through hole, and the free end of the pre-compression spring 7 abuts against the bottom of the valve seat ring clamping groove. In this way, the pre-compression spring 7 gives the valve seat ring 2 a pre-compression force, ensuring that even if the compression ring 3 loosens due to thermal stress, the pre-compression spring 7 can still give the valve seat ring 2 a pre-tightening force, thereby ensuring that the valve seat ring 2 and the valve body 1 are always pressed tightly, and that the valve seat and the valve body 1 are always in tight contact without leakage. Furthermore, the clamping bolt 4 is an M16 bolt, and the guide rod section of the screw is formed by machining a 15mm length along the axial direction of the top of the screw to form a Φ8 smooth rod.
[0021] This device uses a high-temperature and high-pressure resistant sealing gasket 10 added to the bottom of the valve seat ring 2 and the inner conical surface of the valve body 1 to form an elastic seal between the valve seat ring 2 and the valve body 1. Combined with the device's multi-compression structure, this ensures a sealed connection between the valve seat ring 2 and the valve body 1. The multi-compression structure includes: first, tightening the pressure ring 3, which is threaded onto the valve body 1, to compress the valve seat ring 2 and the valve body 1, causing the sealing gasket 10 to deform and fit tightly; second, tightening the specially designed compression bolt 4 on the pressure ring 3, utilizing the pre-compression spring 7 on the compression bolt 4. After tightening the compression bolt 4, the bottom of the pre-compression spring 7 abuts against the valve seat ring 2, providing a pre-compression force to the valve seat ring 2, further ensuring that the valve seat ring 2 and the valve body 1 are always tightly compressed, guaranteeing a tight and leak-free contact between the valve seat and the valve body 1.
[0022] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the concept of this utility model and the contents of the specification and drawings of this utility model, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.
Claims
1. A high and low pressure bypass valve for preventing leakage in a steam turbine, comprising a valve body (1), a valve seat ring (2), and a pressure ring (3), wherein the valve seat ring (2) is installed inside the inlet end of the valve body (1), the valve seat ring (2) has a through hole in the middle forming the steam inlet hole of the valve body (1), and the bottom of the valve seat ring (2) has a boss (9); characterized in that: The boss (9) at the bottom of the valve seat ring (2) is sealed to the inner conical surface of the valve body (1) by a sealing gasket (10). The sealing gasket (10) matches the size of the inner conical surface of the valve body (1). The sealing gasket (10) has a groove on the side facing the boss (9) of the valve seat ring (2) that matches the position and size of the boss (9). The other side of the sealing gasket (10) is a plane that matches the conical surface of the valve body (1). In the assembled state, the boss (9) of the valve seat ring (2) is fitted into the groove of the sealing gasket (10). The valve seat ring (2) is fixed in the valve body (1) by pressing with a pressure ring (3). The pressure ring (3) is detachably connected to the valve body (1).
2. The turbine anti-leakage high and low pressure bypass valve according to claim 1, characterized in that: The sealing gasket (10) is a nickel mesh graphite gasket.
3. The turbine anti-leakage high and low pressure bypass valve according to claim 1, characterized in that: The pressure ring (3) is provided with an external thread, and the inner wall of the valve body (1) is provided with an internal thread that matches the external thread. The outer side of the top surface of the valve seat ring (2) is provided with a pressing groove that matches the size of the pressure ring (3). The outer side of the pressure ring (3) is threadedly connected to the internal thread of the valve body (1). The inner side of the pressure ring (3) is slidably connected to the inner wall of the pressing groove. The bottom surface of the pressure ring (3) abuts against the bottom surface of the pressing groove, thereby pressing the valve seat ring (2) tightly through the pressure ring (3).
4. The turbine anti-leakage high and low pressure bypass valve according to claim 3, characterized in that: Multiple threaded through holes are evenly arranged on the pressure ring (3) with the steam inlet hole as the center, and a clamping bolt (4) is threadedly connected to the threaded through hole of the pressure ring (3).
5. The turbine anti-leakage high and low pressure bypass valve according to claim 4, characterized in that: The clamping bolt (4) includes a head, a screw, and a preload spring (7). The screw includes a threaded section that matches the size of the threaded through hole and a guide rod section that is coaxially connected to the threaded section and has an outer diameter smaller than the threaded through hole. The head is fixed on the threaded section, and the preload spring (7) is fitted on the guide rod section. In the assembled state, the clamping bolt (4) is threadedly installed in the threaded through hole, one end of the preload spring (7) presses against the bottom of the threaded section, and the other end abuts against the bottom of the clamping groove of the valve seat ring (2).
6. The turbine anti-leakage high and low pressure bypass valve according to claim 5, characterized in that: The clamping bolt (4) is an M16 bolt, and the guide rod section is a smooth rod with a length of 15mm and a diameter of Φ8.