Piston U-Cup Seals — Durable Hydraulic Solutions by Polypac

Piston U-Cup Seals by Polypac

Overview

Polypac’s Piston U-Cup seals are engineered for reliable piston sealing in hydraulic cylinders where low friction, fast response and long service life are essential. Designed to energize under pressure, the Piston U-Cup offers superior leakage control and minimal stick-slip — ideal for mobile and industrial hydraulics, heavy machinery and precision actuators.

Key Features

Piston U-Cup seals from Polypac feature a pressure-activated lip geometry that improves sealing as system pressure rises. Benefits include low dynamic friction, tight radial sealing at high pressures, excellent wear resistance, and compatibility with a wide range of hydraulic fluids. Their U-shaped cross-section delivers consistent contact and rapid recovery after decompression.

Materials & Compounds

We manufacture Piston U-Cup seals in PTFE-filled formulations and elastomers such as NBR, FKM, EPDM and silicone. For extreme conditions, Polypac offers specialty compounds including MoS₂-filled PTFE, glass-filled PTFE and FFKM for extraordinary chemical and temperature resistance, ensuring optimal performance across varied operating environments.

Customization & Production

Polypac’s custom rubber ring and O-ring factory spans over 10,000 m², with 8,000 m² of production space and advanced manufacturing equipment. Established in 2008, we combine precision tooling, rapid prototyping and tailored profiles to produce bespoke Piston U-Cup solutions to match unique bore sizes, rod diameters and pressure requirements.

Quality Assurance & Testing

Quality is built into every Piston U-Cup we deliver. Polypac maintains rigorous in-house testing—pressure cycling, abrasion, compression set and fluid compatibility—and collaborates with universities and research institutes to continually refine materials and designs. Our testing protocols ensure reliability under demanding working conditions.

Applications & Ordering

Piston U-Cup seals are suited for hydraulic cylinders in construction equipment, agricultural machinery, industrial presses and aerospace actuators. For volume orders or one-off custom parts, Polypac provides fast quoting, material recommendations and technical support. Contact Polypac to specify dimensions, operating parameters and material grade to get the optimal sealing solution for your system.