SF6 Gas Evacuation and Refilling Unit: Functions, Applications & Selection Guide

SF6 Gas Evacuation and Refilling Unit: Functions, Applications & Selection Guide

In modern power systems, SF6 gas is widely used in high-voltage switchgear, transformers, and other electrical equipment due to its excellent insulation and arc-extinguishing properties. However, long-term operation can lead to issues like gas leakage or purity degradation, which threaten equipment safety and efficiency. This is where the SF6 gas evacuation and refilling unit becomes indispensable—it ensures proper handling of SF6 gas throughout the equipment lifecycle.

What Is an SF6 Gas Evacuation and Refilling Unit?

An SF6 gas evacuation and refilling unit is a specialized device designed to recover, purify, store, and refill SF6 gas in electrical equipment. Its core purpose is to minimize gas waste, reduce environmental impact, and maintain equipment performance by managing SF6 gas with precision.

Core Functions of SF6 Evacuation and Refilling Equipment

High-Efficiency Gas Recovery

It rapidly extracts residual SF6 gas from decommissioned or faulty equipment, achieving a recovery rate of up to 99.5% (per IEC 60480 standards). This prevents greenhouse gas emissions—critical since SF6 has a global warming potential (GWP) 23,500 times that of CO₂ over 100 years.

Advanced Purification

Through multi-stage filtration (including molecular sieve adsorption and particle filtration), the unit removes moisture (to <50 ppm), decomposition byproducts (e.g., SO₂, HF), and particulates. Purified gas meets IEC 60376 standards (purity ≥99.9%), enabling direct reuse.

Precise Refilling

Equipped with digital pressure regulators and flow meters, it refills equipment with SF6 gas at controlled rates (e.g., 0-5 m³/h) and pressures (up to 15 bar), ensuring compliance with manufacturer specifications.

Safe Storage

Integrated high-pressure cylinders (tested to 300 bar) with pressure relief valves store recovered gas securely, preventing leaks during transit or idle periods.

When to Use an SF6 Gas Evacuation and Refilling Unit?

1. Routine Maintenance of Electrical Equipment

During scheduled overhauls of GIS (Gas-Insulated Switchgear) or circuit breakers, the unit first evacuates SF6 gas to allow safe disassembly. Post-repair, it refills the equipment with purified gas to restore insulation performance. For new installations, it ensures initial gas charging meets design pressure (typically 0.4-0.6 MPa for medium-voltage gear).

2. Leakage Response

SF6 gas leaks (detected via infrared sensors or gas detectors) require immediate action. The unit extracts remaining gas before repairs, reducing emissions and safety risks (SF6 displaces oxygen in confined spaces, causing asphyxiation). Post-leak repair, it refills the equipment to optimal pressure.

3. Compliance with Environmental Regulations

Global mandates (e.g., EU F-Gas Regulation, EPA 40 CFR Part 82) restrict SF6 emissions. Using an evacuation and refilling unit aligns with these rules by enabling gas recycling—reducing reliance on new SF6 purchases and lowering carbon footprints.

How to Choose the Best SF6 Evacuation and Refilling Unit?

1. Technical Performance

Recovery Speed: Look for units with ≥2 m³/h recovery rate for large equipment (e.g., power transformers).

Purification Capability: Ensure moisture removal to <30 ppm for high-voltage applications.

Portability: Mobile units (with wheels and compact design) suit fieldwork; stationary units are ideal for fixed substations.

2. Safety Features

Certified by ATEX or IECEx for explosive environments.

Equipped with automatic shutoff valves to prevent over-pressurization.

Gas monitoring sensors (e.g., SF6 concentration alarms) protect operators.

3. After-Sales Support

Reputable brands (e.g., DILO, 3M) offer 24/7 technical support and calibration services. Check for warranty periods (minimum 2 years) and availability of spare parts (e.g., filter cartridges).

Why Invest in an SF6 Gas Evacuation and Refilling Unit?

Beyond regulatory compliance, these units deliver tangible benefits:

Cost Savings: Recycling SF6 reduces new gas purchases by 40-60% annually.

Equipment Longevity: Maintaining proper SF6 purity extends equipment lifespan by 10-15 years.

Sustainability: Each unit prevents ~50 tons of CO₂-equivalent emissions yearly (based on typical usage).

Whether you operate a substation, power plant, or electrical maintenance firm, an SF6 gas evacuation and refilling unit is a critical investment in safety, efficiency, and environmental responsibility. For tailored recommendations, consult with manufacturers to match your equipment type and operational needs.
Need help selecting the right SF6 evacuation solution? Contact our experts for a free assessment.

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