The DH-Type Piston Rod Seal is an advanced Double-Hardness composite sealing element engineered for extreme-duty applications where standard seals fail. It features a sophisticated, two-material construction that delivers superior performance in harsh operating conditions characterized by high pressure, heavy contamination, and significant side loads.
The “DH” designation derives from its unique Dual Hardness profile, which strategically combines materials with differing properties:
Primary Sealing Lip: Manufactured from a specially formulated, high-hardness, abrasion-resistant polyurethane compound. This provides exceptional dimensional stability and resistance to wear and extrusion.
Dynamic Hinge/Support Body: Made from a softer, more flexible elastomer (e.g., NBR). This ensures excellent elastic recovery, adapts to rod runout and eccentricity, and maintains consistent sealing force even under low pressure.
Bonded Construction: The two materials are chemically or mechanically bonded during manufacturing, creating a single, inseparable unit that combines the best properties of both.
Exceptional Extrusion Resistance: The rigid, high-hardness sealing lip resists deformation and extrusion into the rod/cylinder gap, even at very high pressures.
Superior Wear Life: The abrasion-resistant sealing material dramatically extends service life in gritty or abrasive environments.
Excellent Contaminant Exclusion: The combination of a rigid, precise lip and an adaptive body creates a highly effective barrier against external contaminants.
Low & Stable Friction: The rigid lip maintains a controlled contact area, minimizing friction, while the soft body absorbs vibration, preventing stick-slip.
Robustness: Outstanding resistance to mechanical stress, shock loads, and hydraulic pressure spikes.
Pressure Range: 0 – 60+ MPa (ultra-high-pressure capability)
Temperature Range: -35°C to +110°C (material-dependent)
Fluid Compatibility: Broad compatibility with standard hydraulic oils, water-glycol, and biodegradable fluids.
Application: Primarily designed for heavy-duty hydraulic systems in the most demanding environments.
Extreme Hydraulic Presses (forging, metal forming)
Mining & Tunneling Equipment
Offshore & Subsea Hydraulic Systems
Heavy-Duty Construction Machinery (large excavators, bulldozers)
Steel Mill and Foundry Equipment
Precision Required: Demands high-quality, precision-machined gland grooves and superior rod surface finish for optimal performance.
Environment: The ideal choice where pressure, contamination, and durability are the primary, simultaneous challenges.
Not a General-Purpose Seal: Typically reserved for the most severe applications where premium performance is required, justifying its higher cost and installation precision.
Note: The DH-Type represents a pinnacle of composite sealing technology. For critical applications, exact sizing, material grades, and compatibility must be confirmed with the manufacturer’s technical specifications.
Original text from: pneumatic seal https://www.bszzseal.com/
