Shanghai Yushi Technology Development Co., Ltd. (KSTONE) has successfully completed factory acceptance testing for a customized 30m³/h Oil-Free SF₆ Gas Recovery Unit manufactured for ANKURA.
As part of KSTONE’s factory acceptance procedure, the unit underwent pressure holding tests and hood-method leak detection inspections before shipment. The successful completion of these tests confirmed the integrity of all critical sealing points and demonstrated the system’s readiness for long-term field operation.
The project was specifically developed to support SF₆ gas recovery operations in underground electrical facilities, cable tunnels, and GIS installations where equipment dimensions and mobility are critical factors.
As utilities continue to expand underground transmission infrastructure and compact GIS substations, maintenance teams face increasing challenges when transporting equipment into confined work areas.
For this project, ANKURA required a high-performance SF₆ recovery system capable of:
- Operating in narrow underground access routes
- Providing efficient SF₆ gas recovery performance
- Maintaining gas cleanliness through oil-free technology
- Reducing equipment size and transportation complexity
- Supporting direct cylinder filling without an integrated storage vessel
To meet these requirements, KSTONE developed a customized compact recovery solution optimized for mobility and field deployment.
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Only 850 mm wide for tunnel and confined-space access
One of the most distinctive features of this project is its compact mechanical design.
Key dimensions include:
- Width: Only 850 mm
- Height: Approximately 1300 mm
- Compact footprint for tunnel transportation and restricted access areas
Compared with conventional SF₆ recovery carts, the reduced width allows the unit to pass through narrow maintenance corridors, elevator entrances, cable tunnel access points, and underground substation pathways.
This design significantly improves equipment accessibility in locations where space constraints often limit the use of standard recovery systems.
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Oil-free compressor designed for clean SF₆ gas recovery
The unit is equipped with a 30m³/h oil-free recovery compressor designed for clean and efficient SF₆ gas handling.
Benefits of oil-free technology include:
- Reduced risk of gas contamination
- Improved recovered gas quality
- Lower maintenance requirements
- Enhanced environmental performance
- Reliable operation during long-term service
Maintaining gas purity is particularly important for GIS equipment operators seeking to maximize gas reuse and minimize operational costs.
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Direct high-pressure cylinder filling configuration
Unlike traditional recovery systems that utilize built-in storage tanks, this customized solution adopts a direct high-pressure cylinder filling configuration.
Advantages include:
- Reduced equipment weight
- Smaller overall dimensions
- Easier transportation and handling
- Faster deployment on site
- Simplified system structure
Recovered SF₆ gas can be transferred directly into storage cylinders, making the system particularly suitable for mobile maintenance teams and temporary service projects.
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Factory pressure holding test conducted before shipment
Before delivery, KSTONE engineers conducted a series of factory acceptance procedures to ensure system integrity and operational readiness.
Testing included:
- Pressure holding test
- System leak inspection
- Gas tightness verification
- Functional operation testing
- Safety inspection
The successful completion of these procedures confirms the equipment is ready for field commissioning and long-term operation.
Every substation and maintenance environment presents unique operational challenges.
Factors such as site accessibility, available workspace, equipment layout, transportation limitations, and gas handling requirements often necessitate customized recovery solutions.
KSTONE works closely with utilities, EPC contractors, service providers, and equipment manufacturers to develop tailored SF₆ gas handling systems that improve operational efficiency while maintaining the highest standards of safety and environmental responsibility.
KSTONE is the brand of Shanghai Yushi Technology Development Co., Ltd., specializing in SF₆ gas analysis, SF₆ recovery and recycling systems, gas handling equipment, environmental gas solutions, and customized testing instruments for high-voltage electrical applications.
With products serving utilities, GIS manufacturers, laboratories, and power service companies worldwide, KSTONE continues to support the global power industry with reliable and innovative gas management technologies.
For more information about customized SF₆ recovery and gas handling solutions, please contact Shanghai Yushi Technology Development Co., Ltd.
- Learn more about compact SF₆ recovery units for underground maintenance

