PPD Type Piston Rod Seal (Original Design)
Product Description:
The PPD (Positive Pressure Differential) type piston rod seal is a compact, single-acting, dynamic seal specifically engineered for hydraulic and pneumatic cylinders. It is designed to maintain a positive sealing pressure gradient during both the extension and retraction strokes, ensuring minimal leakage, reduced friction, and long service life. The innovative geometry combines a robust primary sealing lip with an integrated, low-friction guide band, eliminating the need for a separate wear ring in many applications.
Key Features & Design Advantages:
Positive Pressure Differential Profile:
The asymmetric sealing lip is designed to utilize system pressure to enhance sealing force during the outstroke (when pressure is highest on the rod side).
A unique relief geometry on the atmospheric side prevents excessive pressure build-up and lip deformation on the instroke, significantly reducing friction and heat generation.
Integrated Functionality:
The seal body incorporates a wide, stable guide band adjacent to the sealing lip. This band provides excellent radial support for the piston rod, preventing metal-to-metal contact and rod vibration, which is critical for consistent sealing and longevity.
Material & Performance:
Manufactured from advanced, homogeneous polyurethane (PU) compounds, offering superior abrasion resistance, excellent extrusion resistance, and compatibility with a wide range of hydraulic fluids and environmental conditions.
Optional material upgrades include PTFE-impregnated compounds for ultra-low friction or hydrogenated Nitrile (HNBR) for high-temperature applications.
Robust Installation:
Features a rigid, square-shaped backup heel that prevents roll, twist, or spiral failure during installation and operation, especially under high-pressure or side-load conditions.
Typical Applications:
Hydraulic cylinders in mobile equipment (construction, agriculture).
Industrial hydraulic presses and automation cylinders.
Medium-to-high pressure pneumatic cylinders requiring minimal stick-slip.
Applications where space is limited, and a combined seal/guide element is beneficial.
Disclaimer:
This is an original conceptual design description (“PPD”) for illustrative purposes. Actual performance depends on precise geometry, material grade, installation, and operating conditions. Always consult with a sealing engineer for specific application validation.
Original text from: pneumatic seal https://www.bszzseal.com/
