SFJ-231 Helium Mass Spectrometry Leak Detector Equipment for GIS Leak Detection

SFJ-231 Helium Mass Spectrometry Leak Detector Equipment for GIS Leak Detection

Helium mass spectrometer leak detector is an instrument for rapid positioning and quantitative measurement of leakage of sealed containers. 

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

1. Background and Principle
High-voltage Gas Insulated Switchgear (GIS) uses SF₆ gas as an insulating and arc-quenching medium. Its sealing integrity directly affects insulation performance, arc-extinguishing capability, and operational safety. SF₆ leakage can lead to reduced insulation strength, arc-quenching failure, and even equipment breakdown.
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.
2. Leak Detection Methods (Based on SFJ-231 Specifications)
The SFJ-231 helium leak detector supports vacuum mode (higher sensitivity) and sniffer mode (convenient for pressurized systems, max allowable pressure: 1500 Pa). 
Vacuum Mode Leak Detection (Higher Sensitivity, Requires Evacuated GIS)
Application: Newly installed, overhauled, or disassembled GIS (where internal SF₆ is removed and vacuum can be applied).
Principle:

• Evacuate the GIS chamber to ≤1 Pa.
• Connect the SFJ-231 via its DN25KF vacuum port.
• Spray helium externally on suspected leak points (e.g., welds, flanges).
• If a leak exists, helium enters the chamber and triggers the detector.
• Advantage: Utilizes SFJ-231’s ultra-high sensitivity (5.0×10⁻¹³ Pa・m³/s) for micro-leak detection.

Vacuum Mode Procedure
Gas Path Connection: Link GIS chamber → SFJ-231 (DN25KF) → vacuum pump (pressure-resistant hoses).
Evacuation: Pump down to ≤1 Pa (lower pressure = better sensitivity).
Detection Settings: Set to vacuum mode, adjust response time (<1s), alarm threshold (per DL/T 596-2021).
Helium Spray Test: Spray helium (5-10mm from the detection point, stay for 3-5s, and observe the signal using the response time of SFJ-231<1s) at a suspicious point (in the order of marking) on the outside of the GIS equipment. If the leak detector shows a sudden increase in the leak rate (synchronized change of numbers and curves), it means that the point is a leak point, and record the leak rate value. Then re-inspection and confirmation.