Understanding API 682 Seal Categories and Their Applications: A Guide to Industry-Compliant Sealing Solutions

API 682 is the globally recognised standard for mechanical seals used in the petroleum, natural gas, and chemical industries. Understanding the categories and types of seals defined by this standard is essential for ensuring safety, reliability, and compliance in critical operations. Reliability Engineering Industries provides API 682-compliant sealing solutions tailored to a range of demanding industrial environments.

‍

Explanation of API 682 Seal Types

API 682 classifies mechanical seals into three types, based on their design and intended use:

Type A – Pusher Seals

• Design: Dynamic secondary seal (O-ring or elastomer) that moves axially with the seal face.
• Applications: Suitable for moderate temperature and pressure environments.
• Advantages: Cost-effective, easy to install, widely used.

Type B – Metal Bellows Seals

• Design: Uses a flexible metal bellows element instead of elastomers for the secondary seal.
• Applications: Ideal for high-temperature, chemically aggressive, or cryogenic environments.
• Advantages: Eliminates elastomer failure risks, excellent thermal stability.

Type C – Non-Pusher Elastomer Seals

• Design: Stationary elastomer secondary seals with a flexible element to maintain seal face contact.
• Applications: Used where minimal axial movement is required and chemical compatibility is critical.
• Advantages: Enhanced reliability in specific applications, especially for fluids prone to crystallisation.

Reliability Engineering Industries offers all three types, providing expert consultation to determine which is most suitable based on operating conditions.

‍

How Different Categories Match Specific Industry Needs

API 682 also defines seal categories based on equipment design, operational severity, and industry standards. These categories help ensure that the seal selected is compatible with the specific equipment and operational environment.

Category 1 – General Industry Applications

• Equipment: Non-API standard pumps and auxiliary systems.
• Pressure/Temperature: Lower pressures and temperatures.
• Industries: Water treatment, light chemical processing.
• Seals: Simpler designs, cost-effective for general service.

Category 2 – Intermediate Service

• Equipment: API 610 compliant pumps.
• Pressure/Temperature: Moderate to high pressures, higher temperatures.
• Industries: Chemical, refining, and petrochemical processes.
• Seals: More robust, designed for higher reliability.

Category 3 – Heavy-Duty, Severe Service

• Equipment: Critical service API 610 pumps.
• Pressure/Temperature: High pressures, extreme temperatures, aggressive fluids.
• Industries: Oil & gas, power generation, offshore drilling.
• Seals: Maximum reliability, extensive testing, and custom engineering.

Reliability Engineering Industries ensures that each seal system matches the specific category of service, offering customised solutions for both standard and complex requirements.

‍

Best Practices for Selecting API-Compliant Seals

Choosing the correct API 682-compliant seal involves a thorough assessment of process conditions, equipment design, and safety requirements. Here are the best practices advised by Reliability Engineering Industries:

1. Assess Process Conditions
   • Understand temperature, pressure, fluid composition, and flow rates.
   • Determine if the process fluid is hazardous, abrasive, or corrosive.
2. Select the Right Seal Type
   • Use Type A for general applications with moderate conditions.
   • Opt for Type B in high-temperature or chemically aggressive environments.
   • Choose Type C where specific sealing arrangements require enhanced elastomer stability.
3. Match the Seal Category
   • For standard applications, Category 1 seals provide adequate reliability.
   • For moderate to severe environments, Category 2 seals ensure durability.
   • For the most demanding conditions, Category 3 seals offer the highest level of performance.
4. Incorporate Suitable API Seal Plans
   • Implement appropriate seal support systems (API Plan 11, 21, 52, 53, etc.) to optimise seal performance and lifespan.
   • Reliability Engineering Industries assists clients in selecting the correct support plans for each seal type and category.
5. Ensure Compliance and Testing
   • Verify that seals meet API 682 and ISO 21049 standards.
   • Engage with manufacturers like Reliability Engineering Industries who provide full material traceability, testing, and certification.
6. Plan for Maintenance and Monitoring
   • Schedule regular inspections based on seal type and operating conditions.
   • Use performance data to adjust maintenance intervals and optimise service life.

By following these best practices, operators can ensure that their seals deliver consistent performance, reduce downtime, and maintain safety in line with industry standards.

‍

API Expertise at Reliability Engineering Industries

Reliability Engineering Industries offers extensive experience in designing, manufacturing, and supplying API 682-compliant mechanical seals. Their in-house engineering team provides customised sealing solutions, ensuring each product meets the specific needs of the client’s application.

Clients benefit from:

• Detailed consultation and seal selection support.
• Seals engineered to the highest industry standards.
• Comprehensive documentation and certification for compliance.
• Ongoing technical support and maintenance guidance.

‍

Contact Reliability Engineering Industries Today

Need assistance selecting the right API 682-compliant mechanical seal? Contact Reliability Engineering Industries to discuss your requirements with our experts and ensure your operations meet industry standards with confidence.