A leading longwall shield rebuilder saw a clear path into OEM manufacturing, aiming to modernize shield designs for greater reliability and target the failure points that had long affected hydraulic shield cylinders industry-wide.
Rather than adapt an existing catalog design, the company worked with System Seals to build a sealing system from the ground up, engineered specifically for the harshest conditions of longwall mining.
The Challenge: To develop a new hydraulic shield cylinder sealing system
To develop a new hydraulic shield cylinder sealing system able to withstand the extreme contamination, side loading, and pressure conditions of longwall mining, without inheriting the failure points of existing designs.
The Solution:
System Seals built the sealing system around five engineering targets. An advanced type 324 scraper was selected for contamination exclusion, preventing the ingress of dirt and abrasive debris.
High-strength composite guide bands were specified for side loading resilience, withstanding uneven forces while maintaining seal alignment.
Materials and geometry were engineered to withstand pressure spikes and shock loads.
Seal forces were optimized for low-friction breakout, ensuring smooth cylinder movement from a static position.
Hydrolysis-resistant materials were selected throughout for compatibility with water- and glycol-based hydraulic fluids.
- Contamination Exclusion: Advanced scraper type 324 prevents the ingress of dirt and abrasive debris.
- Side Loading Resilience: High-strength composite guide bands withstand uneven forces and maintain seal alignment.
- Pressure Spikes & Shock Loads: Materials and geometry engineered for extreme pressure fluctuations and impacts.
- Low-Friction Breakout: Optimized seal forces ensure smooth, efficient cylinder movement from a static position.
- Fluid Compatibility: Hydrolysis resistant materials selected for exceptional resistance to water and glycol-based fluids.
The Result:
The system was independently evaluated at KOMAG under full system longwall pressure. Against an original target of 30,000 cycles, it exceeded 80,000 cycles with no detectable wear, then went on to surpass 120,000 cycles, more than four times the original target, with no bore damage, chrome wear, or contamination ingress. Seal components remained in excellent condition throughout testing.
