What Is SF₆ Gas Recovery & Why It Matters:
Before diving into companies, a brief technical & regulatory context helps with SEO and clarity:
- SF₆ (sulfur hexafluoride) is widely used in switchgear as an insulating and arc-quenching gas. Its dielectric strength, arc suppression, and stability make it preferred in many high- and medium-voltage systems.
- However, SF₆ is a very potent greenhouse gas: its global warming potential (GWP) is many thousands of times higher than CO₂. Therefore, regulatory bodies (e.g., EU F-Gas Regulation, national climate policies) require minimizing emissions, recovering used SF₆, purifying and reusing it, or finding alternatives.
- Key performance metrics for recovery devices include: final vacuum (how well air and moisture are removed), filtration quality (particle/moisture/decomposition byproducts), storage pressure (including liquid SF₆ storage), speed of recovery & filling, safety features, operational convenience, emission minimization, compliance with standards (IEC 62271-4, etc.), and digital features (sensors, data logging, safety control).
Company 1: DILO GmbH (Germany):
Overview:
- DILO is one of the most established manufacturers of SF₆ gas handling/service carts, recovery/purification units, and accessories.
- They cover a wide range: from small portable/mini/micro units to large “mega” service carts for large switchgear compartments.
- Emphasis on emission-free handling (gastight couplings, low residual vacuum), automation / user-friendly UIs, safety, and standards compliance.
Key Product Families & Technical Details:
| Product / Line | Use-Case / Scale | Main Features & Technical Specs |
|---|---|---|
| Compact Series | Entry to mid-level service for medium-sized gas compartments (MV switchgear, mid load) | Recovery, filling, purification, evacuation, venting. Recovery down to < 5 mbar or 1 mbar (depending on type). Semi-automatic operation via 7″ touch screen. Storage in gas or liquid form. Self-closing DILO couplings to reduce leakage. CE / SQL / ASME tank options. |
| Mega Series (L170R01, L400R01 / L600R01, etc.) | Large / very large gas compartments (e.g., large GIS, extra-large breakers) | Final vacuum < 1 mbar. Use of DN40 couplings for faster evacuation/recovery. Automatic control (10″ touch panel). Optional remote operation via smartphone/tablet/laptop. Liquid SF₆ storage tanks. Dual couplings to allow simultaneous evacuation/filling functions. Emission-free when using hermetically sealed couplings. |
| Mini Series / Service Carts for Medium-MV | Medium to small compartments; more mobility required | Example: B143R11V4 model: oil-free compressor (≈1.6 m³/h), vacuum compressor (3.3 m³/h, final vacuum ~5 mbar), vacuum pump for air evacuation (~16-19 m³/h), dry filter (dew point −36 °C), particle filter 1 µm, digital weighing scale for gas cylinders, 7” touchscreen, solid/steerable rollers. |
| Accessories & Upgrades | Enhancing older carts; improving safety/performance | Oil-free vacuum pumps (e.g. B131R41 – 15 m³/h, B131R13 – 35 m³/h, B131R61 – 100 m³/h), final vacuum < 1 mbar. Self-closing couplings. Digital vacuum indication. Emission-free upgrades. |
Strengths
- Very high vacuum performance, especially in the Mega series (<1 mbar), ensures the removal of nearly all air/moisture.
- Good range of product scales: from miniature/mobile to very large.
- Strong safety and emission control: hermetic couplings, self-closing valves, emission-free handling when used properly.
- User-friendly controls, touchscreen UIs, and optional remote/mobile device control.
- Strong compliance with standards (IEC, etc.), and optional certifications (CE, SQL, ASME).
Considerations / Trade-offs
- Large units are heavy and expensive, and need robust infrastructure (power, handling, transport).
- Complexity (filters, vacuum pumps, etc.) means maintenance is critical; filter life, pump maintenance add ongoing costs.
- Operator training is needed to fully exploit the low-emission and safety features.
DILO Mini-Series Modular SF₆ Gas Recovery Units
Company 2: WIKA Alexander Wiegand SE & Co. KG (Germany):
Overview
- WIKA is widely known for pressure, temperature, and level instrumentation; in recent years, they have expanded their SF₆ service/handling equipment under their “GPU” series (gas handling platform).
- Their portfolio includes all-in-one units for filling, cleaning, and recovering SF₆ gas, plus ancillary modules, safety systems, gas measurement, humidity sensors, etc. They position themselves for both safety and ease of use.
Key Products & Technical Details
| Product / Model | Use Case | Technical / Safety Features |
|---|---|---|
| GPU-B-2000 / GPU-S-2000 / GPU-B-3000 / GPU-S-3000 | Full process (“fill, clean, recover, evacuate, vent”) of SF₆ gas for switchgear, accelerators, etc. The S-models include extra safety control. | Oil-less compressor and oil-less vacuum compressor. Dual filtration: particles, moisture, decomposition byproducts. Operation via a large touchscreen (~10″). Option to filter gas on-site to the desired humidity. Very long maintenance intervals (over 2,500 hours) claimed. GPU-S models include SIL2 safety control, reducing the risk of operator error and minimizing emissions. Exceeds relevant IEC norms. |
| Portable Modules / Ancillary Equipment | Smaller installations, service carts, field modules | Examples: GVC-10 vacuum compressor (portable), to extract SF₆ to residual pressure < 5 mbar. GPF-10 filter modules. GWS-10 portable cylinder scale for monitoring gas amounts. (ics-schneider.de) |
Unique / Differentiating Features:
- Safety control: SIL2 in “S” models. This is significant for minimizing human error and leakage. WIKA claims its GPU-S-series makes operator-induced SF₆ emission technically impossible under many misuse scenarios.
- Integrated data-monitoring: large touchscreens, USB/Ethernet for remote maintenance, digital sensors for humidity/temperature/density. Helps in predictive maintenance, logging, and traceability.
- Filter and purification performance aimed at removing moisture, particulates of ~1 µm, and decomposition byproducts (like SO₂, HF, etc.). Ensures that recovered SF₆ meets the required purity for reuse.
Considerations:
- As with any full-scale handler, size, weight, and cost are significant. The GPU-S-3000 and GPU-B-3000 are heavier, more powerful, and costlier.
- High safety and automation features add complexity and cost; maintenance of safety systems must be rigorous.
- Local availability of parts, calibration services, and filters is a factor in many regions.
WIKA GPU-S-2000GPU platform service equipment — full process
Company 3: ENERVAC International ULC (Canada / global):
Overview
- ENERVAC has decades of experience in filtration/purification technologies, especially transformer oil purification and SF₆ gas handling. They make portable recovery units, gas transfer units, evacuation/fill units, and more.
- Their product lines are well-suited for field operations, service contractors, and utilities with mobile requirements.
Key Products & Technical Details
| Product / Model | Application | Key Specs & Features |
|---|---|---|
| GRU-8 PLUS | Larger portable cart-type unit; intermediate between small handcarts and full station skid units | Better than 99.9% SF₆ recovery; oil-less high-pressure compressor (≈1000:1 compression ratio; up to ~69 bar / 1000 psi); filtration to 0.1 microns; can store liquid SF₆; mounted on cart with casters; onboard storage for multiple SF₆ bottles (≈160 kg or more), optionally a larger tank. Colour moisture indicator; long hoses; relatively easy switching between modes. |
| GRU-4 PLUS | Smaller volume handling; smaller switchgear, smaller service jobs | Oil-less high-pressure compressor (~34 bar / 500 psi), portable, mounted on a hand-cart; filtration to 0.1 microns; onboard or auxiliary cylinder storage; evacuation of air & moisture; regulated filling; colour change moisture indicator. |
| GTU PLUS (Gas Transfer Unit) | Transferring gas between cylinders/bottles; consolidating partially used gas; field service jobs | Allows removing SF₆ from one tank/bottle and transferring to another; filtration, drying, purification during transfer; manual re‐pressurization of equipment; rugged enclosure; hoses; safety features. |
| ERFU-2 (Evacuation & Refill Unit) | Very portable for evacuation of air & moisture, then filling switchgear compartments | Rugged, lightweight; regulated filling; vacuum pump; integral vacuum gauge; simple valve switching (3-way ball, etc.); hoses included. |
Strengths
- ENERVAC units are generally robust, mobile, and field-friendly. Good for contractors/utilities needing portability.
- High purity: filtration to 0.1 micron, moisture indicators, and good vacuum performance.
- Relatively easy to use: single-valve operation in some models, simplicity in switching modes (evacuation/refill).
- Good storage capacity in some models (GRU-8, etc.), onboard tanks, ability to consolidate gas bottles.
Considerations
- Some models have lower max pressure or storage than the largest DILO or WIKA units; depending on jurisdiction/switchgear type, you need matching performance.
- Filter replacement, vacuum pump maintenance are ongoing costs.
- For very large switchgear (e.g., very large GIS, extra high voltage), more powerful units might be required.
Enervac GRU-8 SF6 gas recovery
Comparison & Guidance (for Switchgear Professionals):
For a switchgear / T&D utility or OEM deciding among these, or considering what to include in articles / technical spec sheets, here are comparative points and recommendations.
| Criteria | DILO | WIKA | ENERVAC |
|---|---|---|---|
| Vacuum / Residual Air Removal | Excellent: many Mega / Compact units reach < 1 mbar; good evacuation speeds. | Very good: GPU series; oil-less vacuum compressor; residual pressure performance acceptable (< a few mbar) depending on configuration. SIL2 models add safety. | Good: GRU and GTU models often provide vacuum evacuation, moisture removal, etc.; some are more modest in vacuum speed depending on size. |
| Filtration / Purification Quality | Filters for particles (~1 µm), moisture, ability to purify decomposition byproducts; dual filters; dry filters, etc. | Strong filtration modules; 3-in-1 filters; removal of moisture, particles, and decomposed by-products; on-site humidity adjustment. (WIKA blog) | Good: 0.1 µm filters, moisture indicators; purification during recovery/refilling. |
| Storage (Liquid & Gas) & Pressure | Liquid storage options; high storage pressures (e.g. ~50 bar) in some Mega units; cylinder weighing scales, etc. | Cylinder/tank storage options; connection ports for gas cylinders; high allowable pressures for cylinder connections. | Some models offer onboard tanks or external tank connections; GRU-8 has a relatively large storage capacity. |
| Safety & Emission Control | Hermetic/self-closing couplings, emission-free handling when used correctly, and automated features. | Strong: SIL2 safety control in ‘S’ models that reduce the risk of operator error and prevent unintended emissions. | Safety features, but compared to WIKA’s SIL2 control, less emphasis on formal safety control layers in some models. Operators must follow procedures. |
| Ease of Use & Digital / UI Features | Touchscreens (7″, 10″), digital weighing, the ability to use via mobile devices in some Mega units, and remote monitoring options. | 10″ IntelliTouch touchscreen, remote connectivity, sensors, digital data logging; good control over humidity, etc. | Decent control panels; simpler in many portable units; good design for transport; hoses, valves, etc, are well engineered. |
Conclusion & Recommendations for Engineers:
- For projects with large SF₆ volumes (large GIS / high MW equipment), DILO’s Mega Series or ENERVAC’s GRU-8 are strong candidates.
- If safety & operator error minimization are especially important (e.g., regulatory constraints), WIKA’s GPU-S series with SIL2 safety features should be highlighted.
- For mobility/field service / smaller volume work, ENERVAC’s portable units (ERFU, GTU, GRU-4) or DILO’s Mini / Compact series offer good performance with lower cost & easier maintenance.
This content was created with the help of artificial intelligence and from sources and information from the websites of the companies mentioned.
In case of any discrepancies, please contact the Switchgear Content.
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