INDUSTRY COMPONENT

Secondary Seals

Secondary seals are elastomeric or polymeric components in mechanical seals that provide static sealing between rotating and stationary parts, preventing fluid leakage along the shaft.

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Component Specifications

Definition
Secondary seals, also known as static seals or O-rings in mechanical seal assemblies, are critical components that create a leak-proof barrier between the rotating shaft and stationary housing. They compensate for minor misalignments, thermal expansion, and vibration while maintaining sealing integrity under varying pressures and temperatures. These seals are typically installed in gland plates or seal chambers and work in conjunction with primary sealing faces to ensure complete fluid containment in pumps, mixers, and rotating equipment.
Working Principle
Secondary seals operate on the principle of elastic deformation and compression. When installed in a gland or housing groove, the elastomeric material (such as rubber or PTFE) is compressed radially or axially, creating continuous contact pressure against both sealing surfaces. This compression generates a static seal that prevents fluid passage along the shaft or housing interface. The seal maintains contact through elastic recovery forces, accommodating minor movements while resisting extrusion under pressure.
Materials
Common materials include: Nitrile Rubber (NBR) for general purposes (-40°C to 120°C, petroleum-based fluids), Fluorocarbon (FKM/Viton) for high-temperature chemical resistance (-20°C to 200°C), Ethylene Propylene Diene Monomer (EPDM) for steam and hot water (-50°C to 150°C), Perfluoroelastomer (FFKM) for aggressive chemicals (-20°C to 300°C), Polytetrafluoroethylene (PTFE) for chemical inertness (-200°C to 260°C), and Silicone (VMQ) for food-grade applications (-60°C to 230°C).
Technical Parameters
  • Hardness 70-90 Shore A (elastomers)
  • Pressure Range Up to 40 bar (static)
  • Compression Set <25% (after 24h at 150°C)
  • Temperature Range -60°C to 300°C (material dependent)
  • Fluid Compatibility Based on material selection
  • Cross-Section Diameter 1.78mm to 8.4mm
Standards
ISO 3601-1, ISO 6194, AS 568A, DIN 3771, SAE J515

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Secondary Seals.

secondary seal mechanical seal O-ring static seal elastomeric seal pump seal rotary shaft seal fluid containment sealing components Secondary Seals Secondary Seals in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Mechanical Seal Assembly

A precision assembly that prevents fluid leakage between rotating and stationary parts in agitator systems

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Mechanical Seal

A device that prevents fluid leakage between rotating and stationary parts in a pump.

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Seal Assembly

A critical sealing component that prevents leakage of fluids or contaminants in agitator/mixer systems.

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Engineering Analysis

Risks & Mitigation
  • Chemical incompatibility causing swelling/deterioration
  • Extrusion under high pressure
  • Thermal degradation exceeding temperature limits
  • Installation damage from sharp edges
  • Compression set leading to leakage
FMEA Triads
Trigger: Chemical attack from incompatible fluids
Failure: Seal swelling, softening, or cracking
Mitigation: Select chemically resistant materials (FKM, FFKM, PTFE) based on fluid analysis
Trigger: Excessive temperature beyond material limits
Failure: Thermal degradation, hardening, or compression set
Mitigation: Verify operating temperatures and select high-temperature materials (FFKM, silicone) with appropriate safety margins
Trigger: Improper installation or groove design
Failure: Rolling, twisting, or extrusion damage
Mitigation: Follow installation guidelines, use proper tools, ensure groove dimensions per standards, and deburr all edges

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
±0.10mm on cross-section diameter, ±0.20mm on inside diameter (per ISO 3601-1)
Test Method
Pressure testing per ISO 5208, compression set per ASTM D395, fluid compatibility per ASTM D471, hardness per ASTM D2240

Buyer Feedback

★★★★☆ 4.6 / 5.0 (22 reviews)

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"The technical documentation for this Secondary Seals is very thorough, especially regarding technical reliability."

"Reliable performance in harsh Machinery and Equipment Manufacturing environments. No issues with the Secondary Seals so far."

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Frequently Asked Questions

What is the difference between primary and secondary seals in mechanical seals?

Primary seals are the main sealing faces (usually rotating/stationary faces) that handle dynamic sealing, while secondary seals provide static sealing between components and compensate for misalignments.

How often should secondary seals be replaced?

Replacement depends on operating conditions, but typically during mechanical seal overhaul (every 1-3 years) or when signs of hardening, cracking, or compression set exceed 25%.

Can secondary seals handle abrasive fluids?

Standard elastomers may degrade with abrasives; PTFE or FFKM materials with anti-extrusion rings are recommended for abrasive service.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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