Ring Main Unit (RMU) Bellows Assemblies

Bellows assembly plays a critical role in the performance of an RMU. Pliant Bellows has extensive experience and technical expertise in the design and manufacturing of these bellows assemblies. These assemblies are designed to perform in high-voltage environment, enduring repeated mechanical movements and pressure fluctuations while maintaining the structural integrity of the unit.

Main Components of the Bellows Assembly :

Manufacturing and Quality Assurance :

All components are fabricated and assembled in an ISO 3834-2 certified facility, ensuring high-quality welding standards and traceable manufacturing processes.

Welding Process :

Conducted using laser welding machine. Weld joints are ultrasonically cleaned prior to welding to eliminate contamination. Special care is taken to strengthen joints to withstand mechanical shocks and vibrations during circuit breaker operation.

Design Validation :

Every design is tested for durability using an in-house cycle life testing machine, simulating real-world operational stresses. Designs are verified in compliance with EJMA 10 (Expansion Joint Manufacturers Association) standards to ensure long-term performance and safety.

Testing & Inspection :

To ensure leak-proof and reliable performance, each bellows assembly undergoes rigorous testing, including: 100% Pneumatic Testing (Air Bubble Test) -Performed at predefined pressure in a submerged water tank to visually detect any leaks or defects.

Optional Testing Based on Customer Request :

Hydrostatic Pressure Testing – Verifies structural strength and pressure retention capability.

Helium Leak Detection Testing – Highly sensitive method for detecting minute leaks and ensuring gas-tight performance.