The vacuum chamber helium leak detection system for ring main units

The vacuum chamber helium leak detection system for ring main units (RMUs) is an automated testing system specifically designed for the high-voltage gas-insulated switchgear used in the power industry. This system utilizes the vacuum chamber method and helium mass spectrometry leak detection technology to create a pressure differential by simultaneously evacuating the vacuum chamber, and then conducting a leak test after injecting helium into the workpiece. The system is capable of determining large leaks, quantitatively detecting minor leaks, and can automatically recover and recycle the helium gas, improving the efficiency and environmental friendliness of the testing process. It is easy to operate, highly automated, meets the needs of continuous production, and ensures the safety and reliability of the testing.

The main components of the vacuum chamber helium leak detection system for ring main units include:

1. Vacuum Chamber: Used to place the workpiece to be tested, perform vacuum operation, and create a pressure differential between the inside and outside of the workpiece for leak detection.
2. Helium Mass Spectrometer Leak Detector: Detects the presence of helium and determines if there is a helium leak through mass spectrometry analysis technology.
3. Main Vacuum Pump: Used for evacuating the vacuum chamber to ensure it reaches the required vacuum level.
4. Control System: Controls the entire leak detection process, including evacuation, helium injection, testing, and recovery steps.
5. Helium Gas Recovery Device: Recovers the helium gas used in the testing process for recycling.

Technical parameters of the vacuum chamber helium leak detection system for ring main units typically include:

• Vacuum chamber dimensions are customized based on the size of the workpiece.
• Helium gas pressure is adjustable up to 0.05Mpa.
• Working cycle is less than 40 minutes per piece.
• Helium gas recovery rate is between 95%-98%.
• Detectable leak rate is ≤2.8×10^-6 Pa m^3/S.
• System’s own leak rate is ≤10^-9 Pa m^3/s.

Overview of the operation method:

1. Install the workpiece and close the vacuum chamber door.
2. Evacuate the vacuum chamber while injecting high-pressure nitrogen gas into the workpiece for large leak and strength testing.
3. If the test fails, the system will alarm and terminate the testing procedure.
4. If the test passes, release the nitrogen gas and continue to evacuate the workpiece.
5. Inject helium gas for vacuum mode micro-leak detection.

The application of the vacuum chamber helium leak detection system for ring main units not only improves the testing efficiency of power equipment but also reduces the testing costs, making it an indispensable testing tool in the modern power industry.