Seals (O-rings): Inner Diameter 2mm to 500mm

Q: What causes O-ring failure in air valves?

Common failures include extrusion (excessive clearance), compression set (permanent deformation), chemical degradation (incompatible media), abrasion (poor surface finish), and installation damage (twisting, cutting).

Q: How do I select the right O-ring material for pneumatic applications?

Consider operating temperature, media compatibility (compressed air may contain oil/water), dynamic/static application, pressure, and environmental factors (ozone, UV). NBR is standard for general pneumatics; FKM for high-temp or aggressive environments.

Q: What is the proper gland design for O-rings in spool valves?

Glands should provide 15-30% cross-sectional compression, proper clearance to prevent extrusion, adequate volume to accommodate swell, and smooth surfaces (Ra < 0.8 μm). Follow ISO 3601-2 for dimensional standards.

Component Specifications

Definition

O-rings are precision-engineered sealing components with a circular cross-section designed to fit into grooves and create a static or dynamic seal between two or more parts. In air valve applications, they prevent compressed air leakage around spools, shuttles, and ports by deforming under pressure to fill microscopic gaps. Their effectiveness depends on proper gland design, material compatibility, and installation.

Working Principle

O-rings function through elastic deformation and controlled compression. When installed in a gland (groove), they are compressed radially or axially, creating initial sealing contact. Under system pressure, the O-ring is forced against the low-pressure side of the groove, increasing sealing force proportionally to pressure (self-energizing). In dynamic applications (like spool valves), they maintain sealing through controlled friction and lubrication while accommodating minor movements.

Materials

Common materials include Nitrile Rubber (NBR) for general pneumatic applications (-40°C to 120°C, petroleum resistance), Fluorocarbon (FKM/Viton) for high-temperature/high-chemical resistance (-20°C to 200°C), Ethylene Propylene Diene Monomer (EPDM) for steam/water resistance (-50°C to 150°C), and Polyurethane (PU) for high wear resistance. Material selection depends on temperature range, media compatibility (air, lubricants), and dynamic requirements.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Inner Diameter	2mm to 500mm
Compression Set	<25% (per ASTM D395)
Pressure Rating	Up to 40 MPa static, 20 MPa dynamic
Temperature Range	-40°C to 200°C (material dependent)
Hardness (Shore A)	70 to 90
Cross Section Diameter	1.5mm to 10mm

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 3601, AS 568A, DIN 3771, JIS B 2401

Parent Products

This component is used in the following industrial products

Air Valve (Spool/Shuttle)

A directional control valve that regulates airflow in pneumatic systems by shifting a spool or shuttle mechanism.

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Engineering Analysis

Risks & Mitigation

Extrusion under high pressure
Compression set leading to leakage
Chemical degradation from incompatible media
Abrasion from poor surface finish
Installation damage during assembly

FMEA Triads

Trigger: Excessive clearance between mating parts
Failure: Extrusion - O-ring material forced into gap, causing permanent damage
Mitigation: Design glands with proper clearance (per ISO 3601), use backup rings for high pressure, specify appropriate hardness

Trigger: High temperature or improper material selection
Failure: Compression set - O-ring loses elasticity and fails to rebound
Mitigation: Select materials with low compression set (e.g., FKM), ensure operating within temperature limits, consider energizers

Trigger: Incompatible fluids or lubricants
Failure: Chemical degradation - swelling, cracking, or hardening
Mitigation: Verify chemical compatibility charts, use appropriate seals (e.g., EPDM for water, FKM for oils), test with actual media

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

ISO 3601-1 Grade N (normal) for general applications, Grade S (special) for precision applications. Dimensional tolerances typically ±0.10mm on cross-section, ±0.30mm on inner diameter.

Test Method

Pressure testing per ISO 228, compression set per ASTM D395, hardness per ISO 48, fluid resistance per ISO 1817, extrusion resistance per ISO 2230.

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 (O-rings)

1 company lists this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Plumberstar

Shanghai, CN

Also makes: Butterfly Valve, Heating System, Pressure Gauge and 9 more

Listed on the company's own website · profile compiled by CNFX from public sources

Listed there as: “Seals & O-Rings”
View source page ↗ plumberstar.com · checked 2026-08-27

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Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What causes O-ring failure in air valves?