The MYR-type piston rod seal is a specialized buffer seal engineered to work as part of an integrated sealing system for hydraulic and pneumatic cylinders. Its primary mission: absorb pressure spikes and protect the main rod seal from damage, ensuring system longevity and reliability.
The Bodyguard of Hydraulic Systems
Think of the MYR as the first line of defense. Positioned ahead of the primary rod seal, it absorbs the brunt of pressure shocks and provides the majority of rod sealing performance. This protective function shields the main seal from extreme pressures that would otherwise cause premature failure.
Smart Pressure Relief Design
What truly sets the MYR apart is its innovative pressure relief function. The seal allows fluid to bypass and energize the primary rod seal, while trapped fluid between the MYR and main seal can flow back into the cylinder through slotted pedestals. This built-in check valve prevents dangerous pressure buildup between the two seals—a common failure mode in dual-seal systems.
Material Options
| Material | Temperature Range | Best For |
|---|---|---|
| Polyurethane | -40°C to +110°C | Heavy hydraulic, excellent wear resistance |
| NBR (Nitrile) | -30°C to +100°C | Pneumatic applications, finger cylinders |
| Polyacetal | — | Backup rings for anti-extrusion |
Operating Parameters
| Parameter | Hydraulic | Pneumatic |
|---|---|---|
| Max Pressure | Up to 550 bar (8000 psi) | 10 bar |
| Max Speed | 0.5 m/s | — |
| Extrusion Gap | 0.40 mm at 550 bar | — |
| Surface Finish | 0.08-0.3 µm Ra (dynamic) | — |
Why Choose MYR?
Impact Absorption: Reduces peak pressure forces significantly, protecting cylinder components
Pressure Relief: Unique slotted design prevents pressure traps between seals
Extrusion Resistant: Engineered with specific gap limits for each pressure range
Industry Proven: Used in Caterpillar, Deere/Hitachi, and Volvo cylinders worldwide
Groove Compatible: Works with JIS B2401-P series O-ring grooves
System Optimized: Designed to work in perfect harmony with primary rod seals
Installation Guidelines
Always use as part of a two-seal system with a primary rod seal
Verify extrusion gap matches maximum system pressure
Ensure proper surface finish on dynamic and static surfaces
Correct gland dimensions are essential for proper preload
Typical Applications
Heavy-Duty Hydraulics: Excavators, loaders, construction equipment
Mobile Hydraulics: Caterpillar, Deere/Hitachi, Volvo cylinders
Pneumatic Systems: Finger cylinders, small-bore actuators
Industrial Machinery: High-pressure cylinder applications
Extreme Pressure: Systems requiring protection from pressure spikes
The MYR Buffer Seal delivers intelligent protection in a precision package—engineered for demanding applications where pressure spikes happen and main seal protection is essential for system reliability.
Original text from: pneumatic seal https://www.bszzseal.com/
