INDUSTRY COMPONENT

Seals (Piston & Rod)

Critical sealing components for pneumatic actuators that prevent air leakage and maintain pressure differentials between piston and rod chambers.

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Component Specifications

Definition
Seals for pneumatic actuators consist of piston seals that create a barrier between the pressure chambers on either side of the piston, and rod seals that prevent compressed air from escaping along the actuator rod while keeping contaminants out. These dynamic seals must maintain integrity under reciprocating motion, pressure fluctuations, temperature variations, and potential contamination.
Working Principle
Piston seals function by creating a tight interference fit against the cylinder bore, using elastic deformation to maintain contact pressure that prevents air passage between chambers. Rod seals operate similarly against the rod surface, employing lip designs that scrape contaminants inward while maintaining sealing pressure. Both utilize material elasticity and geometric designs that create sealing force proportional to system pressure.
Materials
Nitrile rubber (NBR) for general applications, polyurethane (PU) for high wear resistance, fluorocarbon (FKM/Viton) for chemical/thermal resistance, polytetrafluoroethylene (PTFE) for low friction applications, with reinforcement materials including fabric, metal springs, or plastic components.
Technical Parameters
ParameterTypical rangeNotes & selection driver
Hardness70-95 Shore A
Compression Set<20% (after 24h at 70°C)
Pressure RatingUp to 16 bar (standard), 25 bar (high-pressure)
Temperature Range-40°C to +120°C (varies by material)
Friction Coefficient0.05-0.3 (depending on material/lubrication)
Rod Diameter Compatibility6-100 mm
Piston Diameter Compatibility20-320 mm

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards
ISO 6431, ISO 15552, DIN ISO 21287, DIN 24554

Parent Products

This component is used in the following industrial products

Pneumatic Actuator

A mechanical device that converts compressed air energy into linear or rotary motion to perform work within an industrial system.

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Lift Cylinder / Actuator

A hydraulic or pneumatic cylinder that provides the linear lifting force for the ladle in the lift and seal mechanism.

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Hydraulic Steering Cylinder

A hydraulic actuator that converts hydraulic pressure into linear mechanical force to control the direction of vehicle wheels.

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Engineering Analysis

Risks & Mitigation
  • Seal extrusion under high pressure
  • Chemical degradation from incompatible fluids
  • Abrasive wear from contamination
  • Thermal degradation at extreme temperatures
  • Installation damage during assembly
FMEA Triads
Trigger: Contamination ingress through rod seal
Failure: Abrasive particles damage sealing surfaces, causing leakage and reduced efficiency
Mitigation: Install proper wipers/scrapers, maintain clean air supply, use filtration systems
Trigger: Incompatible operating fluid
Failure: Chemical degradation of seal material leading to swelling, cracking, or loss of elasticity
Mitigation: Verify chemical compatibility charts, select appropriate seal material (FKM for oils, NBR for air)
Trigger: Excessive pressure spikes
Failure: Seal extrusion into clearance gaps causing permanent deformation and leakage
Mitigation: Install pressure relief valves, use anti-extrusion rings, select seals with proper pressure rating

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance
±0.1 mm on critical dimensions, surface roughness Ra 0.2-0.8 μm on sealing surfaces
Test Method
Pressure decay testing per ISO 19973, leakage testing at 1.5x operating pressure, temperature cycling from -30°C to +100°C, endurance testing for minimum 1 million cycles

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation
Request current drawings, revision history, and a signed specification sheet.
Manufacturing capability
Verify equipment lists, process limits, capacity, and representative production evidence.
Inspection readiness
Confirm test methods, calibrated equipment, sampling plans, and traceable reports.
Supplier transparency
Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Seals (Piston & Rod)

Manufacturer profiles associated with Seals (Piston & Rod).

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Frequently Asked Questions

What is the typical service life of pneumatic actuator seals?

Service life varies from 1-10 million cycles depending on material, operating conditions, maintenance, and environmental factors. Proper lubrication and contamination control significantly extend seal life.

How do I select between NBR and polyurethane seals?

NBR offers good general-purpose performance with excellent compression set resistance. Polyurethane provides superior abrasion resistance and extrusion resistance for high-pressure applications but has lower temperature range.

What causes premature seal failure in pneumatic actuators?

Common causes include contamination ingress, improper installation, lack of lubrication, excessive temperatures, pressure spikes beyond rating, chemical incompatibility, and misalignment causing uneven wear.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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