A pressure relief device for a shaft seal heater

Abstract

The utility model discloses a kind of pressure relief devices for shaft seal heater, including shaft seal heater, the right end of the top of shaft seal heater is fixedly connected with alarm, and the left end of the top of shaft seal heater is communicated with first three-way communicating vessel by first pipeline communication.This utility model is provided with critical drain main pipe, second three-way communicating vessel, drain, alarm, water level sensor and bucket, when leakage occurs to shaft seal heater tube bundle, high-pressure water enters second pipeline through first pipeline and first three-way communicating vessel, and enters shaft seal fan with steam, and part of leakage working medium is discharged through fourth pipeline, another part enters critical drain main pipe through newly added second three-way communicating vessel, and is automatically drained to low-level water tank or pit by gravity, since the position of bucket is far lower than steam turbine operation platform, and there is no any rising pipe section, working medium can be effectively prevented from backflow into steam cylinder.

Description

Technical Field

[0001] This utility model relates to the technical field of steam turbine auxiliary systems, specifically a pressure relief device for a shaft seal heater. Background Technology

[0002] Currently, some turbine component manufacturers have not designed bypass systems for their shaft seal heaters on the water side, nor have they installed emergency drainage systems with sufficient capacity on the steam side. When the shaft seal heater experiences tube bundle leakage, high-pressure feedwater will rush into the turbine cylinder in a short period of time through the shaft seal return steam pipeline, which can easily lead to major equipment accidents such as turbine shaft bending and friction between moving and stationary parts. Several power plants have experienced unit outages and equipment damage due to this type of problem.

[0003] In existing technologies, the leakage working medium is usually diverted to a low-level water tank or trench by adding a drain pipe to the outlet pipe of the shaft seal fan. This method can alleviate the problem of water entering the cylinder, but it still has the following shortcomings: 1. It requires a large amount of on-site installation space and restricts the pipeline layout; 2. It cannot achieve early warning of leakage and still relies on the judgment of the operators, resulting in a delayed response. Therefore, we propose a pressure relief device for shaft seal heaters. Utility Model Content

[0004] The purpose of this invention is to provide a pressure relief device for a shaft seal heater to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a pressure relief device for a shaft seal heater, comprising a shaft seal heater, an alarm fixedly connected to the right end of the top of the shaft seal heater, and a first three-way connector connected to the left end of the top of the shaft seal heater through a first pipe, the other two ports of the first three-way connector being connected to second pipes, and the end of the second pipes being connected to a shaft seal fan, the output end of the shaft seal fan being connected to a second three-way connector through a third pipe, and the top of the second three-way connector being connected to a fourth pipe, the third port of the second three-way connector being connected to a water bucket through an emergency drain header, a drain outlet being provided at the upper end of the front of the water bucket, and a water level sensor being fixedly connected to the bottom of the inner cavity of the water bucket.

[0006] Preferably, the inner side of the emergency drainage header is provided with a high-temperature resistant layer, and the outer side of the emergency drainage header is provided with a wear-resistant layer.

[0007] Preferably, the high-temperature resistant layer includes a polytetrafluoroethylene coating and an aluminum oxide coating, and the wear-resistant layer includes a tungsten carbide coating and a silicon nitride coating.

[0008] Preferably, the alumina coating is applied to the inside of the emergency drainage header, and the polytetrafluoroethylene coating is applied to the inside of the alumina coating.

[0009] Preferably, the tungsten carbide coating is applied to the outside of the emergency drainage header, and the silicon nitride coating is applied to the outside of the tungsten carbide coating.

[0010] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. This utility model is equipped with an emergency drainage header, a second three-way connector, a drain outlet, an alarm, a water level sensor, and a water tank. When the shaft seal heater tube bundle leaks, high-pressure water enters the second pipe through the first pipe and the first three-way connector, and then enters the shaft seal fan with the steam. After the leaking working fluid is pressurized by the shaft seal fan, part of it is discharged through the fourth pipe, and the other part enters the emergency drainage header through the newly added second three-way connector. It is then automatically drained to the low-level water tank or pit by gravity. Since the position of the water tank is far below the turbine operating platform and there is no riser section, it can effectively prevent the working fluid from flowing back into the cylinder, thereby ensuring that the leaking working fluid quickly leaves the cylinder, fundamentally eliminating turbine water ingress accidents. Moreover, the overall modification workload is small and the cost is low. It utilizes the natural drop formed by the pipeline layout to achieve automatic drainage without the need for an additional power source. At the same time, it has little impact on the existing system, is suitable for the modification of most operational units, and is also easy to implement in new units.

[0011] 2. This utility model is provided with a high-temperature resistant layer, which includes a polytetrafluoroethylene coating that provides a first layer of high-temperature resistant protection for the inner side of the emergency drainage header, and an alumina coating that provides a second layer of high-temperature resistant protection for the inner side of the emergency drainage header after the polytetrafluoroethylene coating is damaged. It is also provided with a wear-resistant layer, which includes a silicon nitride coating that provides a first layer of wear-resistant protection for the outer side of the emergency drainage header, and a tungsten carbide coating that provides a second layer of wear-resistant protection for the outer side of the emergency drainage header after the silicon nitride coating is damaged. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram showing the connection between the high-temperature resistant layer and the wear-resistant layer of this utility model and the emergency drainage header; Figure 3 This is a schematic diagram of the high-temperature resistant layer structure of this utility model; Figure 4 This is a schematic diagram of the wear-resistant layer structure of this utility model.

[0013] In the diagram: 1. Shaft seal heater; 2. First pipe; 3. First tee connector; 4. Shaft seal fan; 5. Third pipe; 6. Fourth pipe; 7. Emergency drain header; 8. Second tee connector; 9. Second pipe; 10. Drain outlet; 11. Alarm; 12. Water level sensor; 13. Water tank; 14. High temperature resistant layer; 14. Polytetrafluoroethylene coating; 141. Alumina coating; 142. Wear-resistant layer; 15. Tungsten carbide coating; 151. Silicon nitride coating; 152. Detailed Implementation

[0014] 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.

[0015] The components of this application, including shaft seal heater 1, first pipe 2, first tee connector 3, shaft seal fan 4, third pipe 5, fourth pipe 6, emergency drain header 7, second tee connector 8, second pipe 9, drain outlet 10, alarm 11, water level sensor 12, water tank 13, high temperature resistant layer 14, polytetrafluoroethylene coating 141, alumina coating 142, wear-resistant layer 15, tungsten carbide coating 151, and silicon nitride coating 152, are all general standard parts or parts known to those skilled in the art. Their structure and principle can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0016] Example 1: Please see Figure 1The following technical solution is provided, specifically disclosing: It includes a shaft seal heater 1, with an alarm 11 fixedly connected to the right end of the top of the shaft seal heater 1. The left end of the top of the shaft seal heater 1 is connected to a first three-way connector 3 via a first pipe 2. The other two ports of the first three-way connector 3 are each connected to a second pipe 9, and the end of the second pipe 9 is connected to a shaft seal fan 4. The output end of the shaft seal fan 4 is connected to a second three-way connector 8 via a third pipe 5. The top of the second three-way connector 8 is connected to a fourth pipe 6. The third port of the second three-way connector 8 is connected to a water tank 13 via an emergency drain header 7. The water tank 13 is placed in an external low-level water tank or pit. A drain outlet 10 is provided at the upper front of the water tank 13, and a water level sensor 12 is fixedly connected to the bottom of the inner cavity of the water tank 13. The system includes an emergency drain header 7, a second three-way connector 8, a drain outlet 10, and an alarm 11. 1. Water level sensor 12 and water tank 13: When the shaft seal heater tube bundle leaks, high-pressure water enters the second pipe 9 through the first pipe 2 and the first three-way connector 3, and enters the shaft seal fan 4 with the steam. After the leaking working fluid is pressurized by the shaft seal fan 4, part of it is discharged through the fourth pipe 6, and the other part enters the emergency drain header 7 through the newly added second three-way connector 8, and is automatically drained to the low-level water tank or pit by gravity. Since the position of the water tank 13 is far below the turbine operating platform and there is no riser section, it can effectively prevent the working fluid from flowing back into the cylinder, thereby ensuring that the leaking working fluid quickly leaves the cylinder, fundamentally eliminating the turbine water ingress accident. Moreover, the overall modification workload is small and the cost is low. Automatic drainage is achieved by utilizing the natural drop formed by the pipeline layout, without the need for an additional power source. At the same time, it has little impact on the existing system, is suitable for the modification of most operational units, and is also easy to implement in new units.

[0017] Example 2: Please see Figures 2-4The following technical solution is provided, specifically disclosing that: a high-temperature resistant layer 14 is provided on the inner side of the emergency drainage header 7, and a wear-resistant layer 15 is provided on the outer side of the emergency drainage header 7. The high-temperature resistant layer 14 includes a polytetrafluoroethylene coating 141 and an alumina coating 142, and the wear-resistant layer 15 includes a tungsten carbide coating 151 and a silicon nitride coating 152. The alumina coating 142 is applied to the inner side of the emergency drainage header 7, and the polytetrafluoroethylene coating 141 is applied to the inner side of the alumina coating 142. The tungsten carbide coating 151 is applied to the outer side of the emergency drainage header 7, and the silicon nitride coating 152 is applied to the inner side of the alumina coating 142. A high-temperature resistant layer 14 is provided on the outer side of the tungsten carbide coating 151. The polytetrafluoroethylene coating 141 included therein can provide a first layer of high-temperature resistant protection for the inner side of the emergency drainage header 7. The alumina coating 142 can provide a second layer of high-temperature resistant protection for the inner side of the emergency drainage header 7 after the polytetrafluoroethylene coating 141 is damaged. A wear-resistant layer 15 is provided. The silicon nitride coating 152 included therein can provide a first layer of wear-resistant protection for the outer side of the emergency drainage header 7. The tungsten carbide coating 151 can provide a second layer of wear-resistant protection for the outer side of the emergency drainage header 7 after the silicon nitride coating 152 is damaged.

[0018] The working principle of this application is as follows: An emergency drainage header 7, a second three-way connector 8, a drain outlet 10, an alarm 11, a water level sensor 12, and a water tank 13 are installed. When a leak occurs in the shaft seal heater tube bundle, high-pressure water enters the second pipe 9 through the first pipe 2 and the first three-way connector 3, and then enters the shaft seal fan 4 with the steam. After being pressurized by the shaft seal fan 4, part of the leaking working fluid is discharged through the fourth pipe 6, and the other part enters the emergency drainage header 7 through the newly added second three-way connector 8, and is automatically drained to a low-level water tank or pit by gravity. Because the position of the water tank 13 is far below the turbine operating platform and there is no riser section, it effectively prevents the working fluid from flowing back into the cylinder, thus ensuring that the leaking working fluid quickly leaves the cylinder, fundamentally eliminating turbine water ingress accidents, and comprehensively modifying the system. With minimal workload and low cost, it utilizes the natural drop created by the pipeline layout to achieve automatic drainage without requiring an additional power source. Furthermore, it has minimal impact on existing systems, making it suitable for retrofitting most operational units and easy to implement in new units. A high-temperature resistant layer 14 is provided, including a polytetrafluoroethylene coating 141 that provides the first layer of high-temperature protection to the inside of the emergency drainage header 7, and an alumina coating 142 that provides a second layer of high-temperature protection to the inside of the emergency drainage header 7 after the polytetrafluoroethylene coating 141 is damaged. A wear-resistant layer 15 is also provided, including a silicon nitride coating 152 that provides the first layer of wear-resistant protection to the outside of the emergency drainage header 7, and a tungsten carbide coating 151 that provides a second layer of wear-resistant protection to the outside of the emergency drainage header 7 after the silicon nitride coating 152 is damaged.

[0019] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pressure relief device for a shaft seal heater, comprising a shaft seal heater (1), characterized in that: An alarm (11) is fixedly connected to the right end of the top of the shaft seal heater (1), and the left end of the top of the shaft seal heater (1) is connected to a first three-way connector (3) through a first pipe (2). The other two ports of the first three-way connector (3) are connected to a second pipe (9), and the end of the second pipe (9) is connected to a shaft seal fan (4). The output end of the shaft seal fan (4) is connected to a second three-way connector (8) through a third pipe (5), and the top of the second three-way connector (8) is connected to a fourth pipe (6). The third port of the second three-way connector (8) is connected to a water bucket (13) through an emergency drain header (7). A drain outlet (10) is opened at the upper end of the front of the water bucket (13), and a water level sensor (12) is fixedly connected to the bottom of the inner cavity of the water bucket (13).

2. The pressure relief device for a shaft seal heater according to claim 1, characterized in that: The inner side of the emergency drainage header (7) is provided with a high temperature resistant layer (14), and the outer side of the emergency drainage header (7) is provided with a wear resistant layer (15).

3. A pressure relief device for a shaft seal heater according to claim 2, characterized in that: The high-temperature resistant layer (14) includes a polytetrafluoroethylene coating (141) and an alumina coating (142), and the wear-resistant layer (15) includes a tungsten carbide coating (151) and a silicon nitride coating (152).

4. A pressure relief device for a shaft seal heater according to claim 3, characterized in that: The alumina coating (142) is applied to the inside of the emergency drainage header (7), and the polytetrafluoroethylene coating (141) is applied to the inside of the alumina coating (142).

5. A pressure relief device for a shaft seal heater according to claim 3, characterized in that: The tungsten carbide coating (151) is applied to the outside of the emergency drainage header (7), and the silicon nitride coating (152) is applied to the outside of the tungsten carbide coating (151).

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