U-Cups

Single-acting rod & piston seal

A self-energising U-section seal whose flexible lips are pressure-actuated for low-friction single-acting rod and piston sealing.

Self-energising lips — sealing force rises with pressure
Low running friction for smooth actuation
Abrasion-resistant polyurethane for long life
Symmetric and asymmetric rod / piston profiles
Simple single-groove installation

Temperature: -30°C to +110°C (PU) / +200°C (PTFE)
Pressure: Up to 400 bar (with back-up ring)
pH range: 4 – 10

Polyurethane U-cup hydraulic rod seal showing the U-section sealing lips — Hydraulic SealsREF · u-cup

Technical DatasheetSPEC

The numbers, on the record

Every figure below is the specification we hold ourselves to — material, service envelope, media compatibility and conformance. Download it as a standalone document for your dossier.

SealGuard

Technical Datasheet

Doc No.: DS-U-CUP
Revision: Rev. A
Issue: 2026-Q3
Class: Hydraulic Seals

U-Cups

Single-acting rod & piston seal

01

Material & Construction

Polyurethane or nitrile U-section seal; fabric-reinforced and FKM grades available

02

Service Envelope

Temperature range	-30°C to +110°C (PU) / +200°C (PTFE)
Pressure rating	Up to 400 bar (with back-up ring)
pH range	4 – 10

03

Media Compatibility

Hydraulic oilsWater-glycol fluidsMineral oilsEmulsions

04

Dimensions & Sizing

Rod Ø8–360 mm · bore Ø16–500 mm · metric & inch · ISO 5597 / 6195

05

Standards & Conformance

ISO 5597
ISO 6195
ISO 6547

06

Certifications

ISO 9001
RoHS / REACH

07

Additional Specifications

Hardness	92–95 Shore A (PU)
Max speed	0.5 m/s reciprocating

Action	Single-acting, self-energising
Back-up	Add for pressure > 250 bar / large gap

Specify & QuoteORDER

Build your line item

Choose the material grade and size that match your duty, set a quantity, and add a fully-specified line to your quote. No prices, no obligation — our engineers confirm specification and lead time on every enquiry.

01

Material grades

Polyurethane (PU / AU) 92–95 Shore A
NBR / nitrile 80–90 Shore A
Fabric-reinforced NBR (high pressure)
FKM (high temperature / chemical)
PTFE-faced energised U-cup

02

Sizes & configurations

Rod Ø8–360 mm
Bore Ø16–500 mm
Metric (ISO 5597 / 6195)
Inch (cylinder) sizes
Symmetric or asymmetric profile
Custom sizes to drawing

In ServiceUSE

Where it holds the line

The U-cup is the backbone of hydraulic cylinder sealing. Its U-shaped cross-section is self-energising: system pressure forces the lips apart against the rod and groove, so sealing force rises with pressure while running friction stays low at rest. Moulded from abrasion-resistant polyurethane or nitrile, it installs easily in a single groove and delivers reliable single-acting service across millions of cycles. SealGuard supplies symmetric and asymmetric profiles for both rod and piston duty to ISO 5597 and 6195.

Typical applications

01Hydraulic cylinder rod and piston sealing
02Mobile and construction hydraulics
03Presses and industrial actuators
04Material-handling and lift cylinders
05Single-acting general hydraulics

Industries served

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Let’s specify it

Specify this seal for your service.

Send us the media, temperature, pressure and motion for your duty and our engineers will confirm the right material grade, size and standard for your application.

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