1500Pa Sniffer Helium Leak Detection Equipment for Power Industry

Technical Parameters of SFJ-231 Helium Leak Detector

Application of SFJ-231 Helium Mass Spectrometer Leak Detector in High-Voltage GIS Equipment / SF₆ Gas Tightness Testing in the Power Industry

Helium mass spectrometry leak detection is a core method for GIS sealing tests due to helium’s (He) small molecular size, high permeability, non-reactivity with SF₆, and the ultra-high sensitivity of the SFJ-231 leak detector (minimum detectable leak rate: 5.0×10⁻¹³ Pa・m³/s in vacuum mode). By using helium as a tracer gas, the detector captures helium signals to locate leaks and quantify leak rates.
The SFJ-231 supports vacuum mode (higher sensitivity) and sniffer mode (convenient for pressurized systems, max allowable pressure: 1500 Pa). For GIS equipment, sniffer method can be used below:

Sniffer Mode Leak Detection (For Pressurized GIS, On-Site Convenience)
Application: Operational GIS (internally pressurized with SF₆, but pressure must be ≤1500 Pa; if higher, reduce pressure first).
Principle: Inject a small amount of helium (mixed with SF₆, without affecting the insulation performance) into the GIS equipment, use the spary gun of SFJ-231 (connected through I/O interface) to get close to the suspicious point, if there is a leak, the helium will leak along with the SF₆, which will be captured by the spray gun and transmitted to the leak detector to realize the leakage rate detection.
Technical suitability: The minimum leak rate of 5.0×10^-⁹ Pa・m³/s in sniffer mode and a response time of <1s make it possible to quickly locate leaks, which makes it suitable for rapid on-site inspections.

Steps of Leak Detection in Suction Gun Mode (GIS equipment with pressure)
1. Tracer Gas Injection
Inject helium gas into the GIS equipment: through the filling port of the equipment, inject pure helium according to 1% to 5% of the volume of SF₆ (make sure that the mixture is uniform, and leave it for more than 30min, so as to make helium gas diffuse to all the chambers).
2. Sniffer connection and parameter setting
Connect the sniffer to SFJ-231 via I/O connector (8 inputs and 8 outputs), switch to “Sniffer Mode” in the touch panel, set the sniffer flow rate (default value, or adjust it according to the site), and the leakage rate alarm threshold.
3. Sniffer detection
Hold the sniffer in hand, close to the suspicious point (distance 1-3mm), move slowly (speed ≤5cm/s), make sure to cover the whole sealing surface.
If the leak detector shows that the leakage rate exceeds the threshold (e.g. 5.0×10^-⁹ Pa・m³/s), mark the point as a leakage point and record the leakage rate and location.
4. Quantitative testing
Stabilize the sniffer against the leakage point for 10s, take the average leakage rate as the final result.