A water level monitoring and water replenishing system for a multi-stage water seal of a shaft seal heater

Abstract

The utility model belongs to shaft seal heater water level control technical field especially relates to a kind of water level monitoring and water replenishing system of shaft seal heater multistage water seal, shaft seal heater is equipped with water drain outlet, water drain outlet is connected multistage water seal inlet by pipeline, multistage water seal outlet connects exhaust device, multistage water seal inlet and multistage water seal outlet are all installed manual valve, the multistage water seal parallel bypass pipeline, multistage water seal inlet and multistage water seal outlet are all installed differential pressure transmitter, multistage water seal inlet end top is connected emptying pipeline, emptying valve is connected on emptying pipeline, multistage water seal outlet end top is connected water replenishing pipeline, water replenishing pipeline parallel bypass pipeline, solenoid valve is connected on water replenishing pipeline, both ends of solenoid valve are connected manual valve on water replenishing pipeline, differential pressure transmitter and solenoid valve are all connected control system. The system realizes water level on-line monitoring and automatic water replenishing, prevent water level too high or too low, improve operating stability.

Description

Technical Field

[0001] This utility model belongs to the field of water level control technology for shaft seal heaters, and particularly relates to a water level monitoring and water replenishment system for a multi-stage water seal of a shaft seal heater. Background Technology

[0002] The shaft seal heater is a key component of the turbine shaft seal system. Its function is to collect steam leaks from the shaft seals of each cylinder and from the valve stems of the turbine, and to use the heat energy of this steam to heat the main condensate, thereby reducing heat loss. During normal operation, the shaft seal heater needs to maintain a slight negative pressure inside to prevent shaft seal steam from leaking out, while ensuring that the condensate from the return steam from the shaft seal is smoothly discharged into the condenser.

[0003] Multi-stage water seals, as an important component of the shaft seal heater condensate system, primarily function to increase the resistance of the condensate return water and maintain the condensate water level of the shaft seal heater. Under ideal operating conditions, the condensate from the shaft seal heater passes through multiple water seals and then returns to the condenser steam side at a certain height; the flow resistance plus the height difference is exactly equal to the condenser vacuum. However, in actual operation, due to the constantly changing operating conditions of the unit, the multi-stage water seals of the shaft seal heater often encounter the following problems:

[0004] (1) Poor drainage: Due to the failure of the multi-stage water seal outlet valve, improper adjustment, or air or water blockage inside the multi-stage water seal, the shaft seal heater is not drained properly, resulting in an abnormal rise in the water level of the shaft seal heater. This not only affects the normal working efficiency of the shaft seal heater, but also causes a series of safety problems, such as steam leakage.

[0005] (2) Insufficient return water resistance: When the multi-stage water seal pipe loses water, the steam side of the shaft seal heater is directly connected to the condenser. Since the steam side of the shaft seal heater is directly connected to the atmosphere through the shaft fan, the unit vacuum will drop sharply, which will seriously affect the stability of the unit operation.

[0006] (3) Visibility and monitoring deficiencies: Most existing multi-stage water seals are made of metal or opaque materials, lacking visual observation windows or built-in monitoring devices. Operators find it difficult to intuitively judge the water seal condition and need to rely on indirect parameters to infer it, resulting in monitoring blind spots.

[0007] (4) Insufficient operational stability: During the start-up and shutdown of the unit, the steam pressure of the shaft seal fluctuates frequently, which can easily cause the water level inside the water seal to oscillate. If the water level is too high, it may cause the water seal to overflow and affect the condenser vacuum; if the water level is too low, it will cause the seal to fail and air to leak in, causing the back pressure to rise.

[0008] (5) Lack of fault warning: When the water seal is short of water, the alarm cannot be triggered in time. Operators can only find the problem through regular inspections, which poses a safety hazard during the inspection interval. The equipment may be damaged or the system performance may be reduced due to the failure to deal with the water shortage fault in time.

[0009] (6) Inefficient water replenishment operation: Currently, water replenishment relies on manual on-site operation based on experience. There is a lack of water level feedback mechanism, making it impossible to accurately control the amount of water replenished. Operators have difficulty judging whether the water seal is full, which can easily lead to insufficient or excessive water replenishment, increasing the complexity of operation and the risk of human error, while also consuming a lot of manpower and time costs. Utility Model Content

[0010] The purpose of this invention is to provide a water level monitoring and water replenishment system for a multi-stage water seal in a shaft seal heater, thereby solving the problems mentioned in the background art.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A water level monitoring and water replenishment system for a multi-stage water seal in a shaft seal heater includes a shaft seal heater, a multi-stage water seal, and a steam exhaust device. The shaft seal heater has a drain outlet, which is connected to the inlet of the multi-stage water seal via a pipeline. The outlet of the multi-stage water seal is connected to the steam exhaust device. Both the inlet and outlet of the multi-stage water seal are equipped with manual valves. The multi-stage water seal is connected in parallel to a bypass pipeline, which is connected to a manual valve. Differential pressure transmitters are installed at both the inlet and outlet of the multi-stage water seal. The top of the inlet of the multi-stage water seal is connected to a venting pipeline, which is connected to a venting valve. The end of the venting pipeline is connected to a collection tank. The top of the outlet of the multi-stage water seal is connected to a water replenishment pipeline, which is connected in parallel to the bypass pipeline. A solenoid valve is connected to the water replenishment pipeline, and manual valves are connected to both ends of the solenoid valve. A manual valve is also connected to the bypass pipeline. The differential pressure transmitter and the solenoid valve are both connected to a control system, which is connected to an alarm. The multi-stage water seal water level settings of the solenoid valve, the alarm, and the differential pressure transmitter are interlocked.

[0013] Preferably, the shaft seal heater is further provided with an emergency drain interface, which is connected to an emergency drain pipeline. The end of the emergency drain pipeline is connected to a steam exhaust device, and an electric valve is installed on the emergency drain pipeline. The electric valve is interlocked with the liquid level setting of the shaft seal heater.

[0014] Preferably, the differential pressure transmitter is a high-precision differential pressure transmitter.

[0015] The beneficial effects achieved by this utility model are as follows:

[0016] (1) The differential pressure signal is converted into a real-time water level signal by the differential pressure transmitter and transmitted to the control system in real time to monitor the water level of the multi-stage water seal. The alarm is triggered when the water level is high or low, avoiding vacuum deterioration due to the inability to determine the water level. There is no monitoring blind spot, and the safety hazards during the inspection interval of the operators are prevented.

[0017] (2) By interlocking the solenoid valve on the water supply pipeline with the liquid level setting, automatic water supply can be achieved when the water level is low. This eliminates the need for staff to operate the water supply on-site, reducing workload and preventing the unit vacuum from dropping sharply due to insufficient return water resistance. At the same time, it avoids the problem of insufficient or excessive water supply caused by the difficulty for operators to judge whether the water seal is full, thus reducing manpower and time costs.

[0018] (3) By adjusting the manual valve opening of the bypass pipe and the water supply pipe of the multi-stage water seal, the pressure in the multi-stage water seal system is relieved, the water column height in the multi-stage water seal is adjusted, and the water seal height is ensured to be within a suitable range to prevent the water seal from being too high or too low; at the same time, the bypass pipe serves as a backup channel, and when the main channel is blocked, the system continues to operate normally through the bypass pipe.

[0019] (4) An emergency drainage pipeline is added, and the emergency drainage electric valve is interlocked with the liquid level of the shaft seal heater. When the water level is high, the electric valve is open, and when the water level is low, the electric valve is closed, so as to avoid the abnormal rise of the water level of the shaft seal heater due to the poor drainage of the multi-stage water seal during operation.

[0020] (5) Through differential pressure transmitter, solenoid valve, water supply pipeline and bypass pipeline of water supply pipeline, online monitoring of water level of multi-stage water seal and automatic water supply can be realized to prevent water level from being too high or too low, avoid frequent fluctuation of shaft seal steam pressure, and prevent water level oscillation inside water seal, thereby improving operational stability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram of the multi-stage water seal structure in an embodiment of this utility model.

[0023] Explanation of reference numerals in the attached drawings: 1. Shaft seal heater; 101. Drain outlet; 102. Emergency drain interface; 2. Multi-stage water seal; 3. Exhaust device; 4. Emergency drain pipeline; 5. First manual valve; 6. Second manual valve; 7. First bypass pipeline; 8. Third manual valve; 9. Electric valve; 10. First differential pressure transmitter; 11. Second differential pressure transmitter; 12. Drain pipeline; 13. Drain valve; 14. Make-up water pipeline; 15. Second bypass pipeline; 16. Solenoid valve; 17. Fourth manual valve; 18. Fifth manual valve; 19. Sixth manual valve; 20. Control system; 21. Alarm; 22. Collection tank. Detailed Implementation

[0024] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and embodiments.

[0025] like Figure 1-2As shown, a water level monitoring and water replenishment system for a multi-stage water seal in a shaft seal heater includes a shaft seal heater 1, a multi-stage water seal 2, and a steam exhaust device 3. The shaft seal heater 1 is equipped with a drain outlet 101 and an emergency drain interface 102. The drain outlet 101 is connected to the inlet of the multi-stage water seal 2 via a pipeline. The outlet of the multi-stage water seal 2 is connected to the steam exhaust device 3. The emergency drain interface 102 is connected to an emergency drain pipeline 4. The end of the emergency drain pipeline 4 is connected to the steam exhaust device 3. A first manual valve 5 is installed at the inlet of the multi-stage water seal 2, and a second manual valve 6 is installed at the outlet of the multi-stage water seal 2. Water seal 2 is connected to the first bypass pipe 7 in parallel. A third manual valve 8 is connected to the first bypass pipe 7. An electric valve 9 is installed on the emergency drain pipe 4. The electric valve 9 is interlocked with the liquid level setting of the shaft seal heater 1. A first differential pressure transmitter 10 is installed at the inlet of multi-stage water seal 2. A second differential pressure transmitter 11 is installed at the outlet of multi-stage water seal 2. The top of the inlet end of multi-stage water seal 2 is connected to the drain pipe 12. A drain valve 13 is connected to the drain pipe 12. The end of the drain pipe 12 is connected to the collection tank 22. The top of the outlet end of multi-stage water seal 2 is connected to the water supply pipe 14. 4. A second bypass pipe 15 is connected in parallel. A solenoid valve 16 is connected to the water supply pipe 14. A fourth manual valve 17 is connected to the left end of the solenoid valve on the water supply pipe 14, and a fifth manual valve 18 is connected to the right end. A sixth manual valve 19 is connected to the second bypass pipe 15. The first differential pressure transmitter 10, the second differential pressure transmitter 11, and the solenoid valve 16 are all connected to the control system 20. The control system 20 is connected to the alarm 21. The first differential pressure transmitter 10, the second differential pressure transmitter 11, the solenoid valve 16, the alarm 21, and the multi-stage water seal converted by the differential pressure transmitter are connected. The water level is interlocked; the differential pressure signal is converted into a real-time water level signal through the first and second differential pressure transmitters to monitor the water level of the multi-stage water seal in real time. High and low water level thresholds are set on the control system. Based on the water level data, the solenoid valve opens or closes to achieve automatic water replenishment. At the same time, the alarm sounds when the water level is high or low to prevent vacuum deterioration due to the inability to determine the water level. The emergency drain pipeline completes drainage in abnormal conditions to avoid the shaft seal heater efficiency from dropping sharply due to high water level, or even steam leakage accidents.

[0026] Working principle: After the steam on the steam side of the shaft seal heater 1 condenses into water, it flows through the drain outlet 101 and the first manual valve 5 to the multi-stage water seal 2. Under the action of static pressure, it flows by gravity in stages, and enters the exhaust device 3 through the second manual valve 6 at the outlet of the multi-stage water seal. The first differential pressure transmitter 10 and the second differential pressure transmitter 11 at the inlet and outlet of the multi-stage water seal 2 convert the differential pressure signal into a real-time water level signal, which is transmitted to the control system 20 and displayed on the control system display screen. High and low water level thresholds are set on the control system 20, and high and low water level alarms and interlocks are used. When the water level is lower than the set value, the control system 20 issues a command to open the solenoid valve 16, and simultaneously confirms that the fourth manual valve 17 and the fifth manual valve 18 of the multi-stage water seal are open, ensuring that the water supply pipeline 14 is unobstructed, and replenishing demineralized water into the multi-stage water seal 2. At the same time, the alarm 21 sounds, facilitating timely inspection by staff. As water replenishment proceeds, the water level in the multi-stage water seal 2 gradually rises. When the water level reaches the set threshold range, the control system 20 determines that the multi-stage water seal has returned to normal working status and then issues a command to close the solenoid valve 16 to stop water replenishment. If the solenoid valve 16 fails to automatically replenish water, water is replenished by opening the sixth manual valve 19 on the second bypass pipeline 15. If air or water blockage occurs inside the water seal, causing an abnormal rise in the water level of the shaft seal heater 1, the shaft seal heater 1 is interlocked for protection through the emergency drain pipeline 4 connected to the emergency drain interface and the electric valve 9. When the water level is higher than the set value, the electric valve 9 is opened, and the alarm 21 sounds, facilitating timely inspection by staff. When the water level drops to the normal range, the electric valve 9 is closed. When the liquid level in the shaft seal heater is higher than the set condition and the emergency drain fails to open in time, the third manual valve 8 on the first bypass pipe 7 can be adjusted to relieve the pressure of the multi-stage water seal 2 system. When the multi-stage water seal is initially replenished, the drain valve 13 of the drain pipe 12 is opened, and closed when the liquid of the multi-stage water seal 2 is discharged into the collection tank 22.

Claims

1. A water level monitoring and water replenishment system for a multi-stage water seal in a shaft seal heater, characterized in that, The system includes a shaft seal heater, a multi-stage water seal, and a steam exhaust device. The shaft seal heater has a drain outlet, which is connected to the multi-stage water seal inlet via a pipeline. The multi-stage water seal outlet is connected to the steam exhaust device. Both the multi-stage water seal inlet and outlet are equipped with manual valves. The multi-stage water seal is connected to a bypass pipeline in parallel, and a manual valve is connected to the bypass pipeline. Differential pressure transmitters are installed at both the multi-stage water seal inlet and outlet. The top of the multi-stage water seal inlet is connected to a drain pipeline, which is connected to a drain valve. The end of the drain pipeline is connected to a collection tank. The top of the multi-stage water seal outlet is connected to a water supply pipeline, which is connected to the bypass pipeline in parallel. A solenoid valve is connected to the water supply pipeline, and manual valves are connected to both ends of the solenoid valve on the water supply pipeline. A manual valve is also connected to the bypass pipeline. The differential pressure transmitter and solenoid valve are connected to a control system, which is connected to an alarm. The differential pressure transmitter, solenoid valve, alarm, and the multi-stage water seal water level converted by the differential pressure transmitter are interlocked.

2. The water level monitoring and water replenishment system for a multi-stage water seal of a shaft seal heater according to claim 1, characterized in that, The shaft seal heater is also equipped with an emergency drain interface, which is connected to an emergency drain pipeline. The end of the emergency drain pipeline is connected to a steam exhaust device, and an electric valve is installed on the emergency drain pipeline. The electric valve is interlocked with the liquid level setting of the shaft seal heater.

3. The water level monitoring and water replenishment system for a multi-stage water seal of a shaft seal heater according to claim 1, characterized in that, The differential pressure transmitter is a high-precision differential pressure transmitter.

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