Mechanical Packings
Mechanical packing is the oldest method of keeping fluid from escaping past a shaft, and is still the most common method of sealing valve stems. Of course, material science has greatly improved the results you can achieve, but the basics are the same today as they were 100 years ago. High quality engineered fibers are mechanically braided into specific patterns to yield the desired physical characteristics. The results can vary from low-cost to high-performance.
Low Cost – Limited Service Packings:
Flax with Wax – Marine packing – Water service, slow shaft speeds
Ramie with Wax – Marine packing – Water service, slow shaft speeds, reduced deterioration
Reliable General Service Packings:
Acrylic yarns – General service – Low temperature, mild chemical
Glass yarns – General service – Some high temperatures, low speed
Expanded PTFE – Pump packing – Good chemical range, moderate to high speed
Specialty High Performance Packings:
Carbon Yarns – Valve packing – High temperature, High pressure Good chemical range
Graphite Yarns – Valve packing – High temperature, High pressure Good chemical range
Flexible Graphite – Valve packing – High temperature, High pressure Good chemical range, Emission control
Call Advanced Sealing for specific recommendations for your application.