What are the differences between static sealing and dynamic sealing of fluorine rubber sealing rings?

The main differences between static sealing and dynamic sealing of fluorine rubber sealing rings lie in five aspects: application scenarios, sealing principles, design requirements, temperature adaptability, and performance emphasis. The specific analysis is as follows:

1. Application Scenarios

Static Sealing: Used for components without relative motion, such as flange connections, pipe joints, equipment shells, etc. By compressing the sealing ring to fill the gap between the contact surfaces, it prevents fluid leakage.

Dynamic Sealing: Used for components with relative motion, such as rotating shafts (motors, pumps), reciprocating rods (cylinders, hydraulic cylinders). It needs to maintain the seal during movement to prevent medium leakage and reduce friction and wear.

2. Sealing Principles

Static Sealing:

Depends on the elastic deformation of the sealing ring to fill the microscopic unevenness of the contact surface, forming a static barrier.

The sealing effect is mainly determined by the compression ratio, contact pressure, and material resilience.

Dynamic Sealing:

Contact type (such as O-rings, lip seals): The sealing lip directly contacts the moving surface, forming a dynamic seal through fluid pressure and elastic force.

Non-contact type (such as labyrinth seals, spiral seals): Utilizing the principles of fluid dynamics, it achieves sealing through gap control or pressure balance, with minimal friction but higher leakage rate.

3. Design Requirements

Static Sealing:

Key points: Material's resistance to medium, compression permanent deformation rate, and resistance to creep.

Advantage of Fluororubber: Resistant to high temperatures (200-250°C for long-term use), resistant to chemical corrosion (acid, alkali, oil, solvents), and resistant to compression deformation.

Dynamic Sealing:

Contact type: Needs to balance sealing performance and friction. The material should have a low friction coefficient, be wear-resistant, and resistant to wear. The applicable temperature range of fluororubber dynamic seals is typically -15°C to 280°C, and special formulations are required for high temperatures.

Non-contact type: Requires precise control of the gap and fluid parameters. Fluororubber is mostly used for auxiliary sealing (such as bellows seals).

4. Temperature Adaptability

Static Sealing: The temperature range of fluororubber static seals is wider, with the general grade ranging from -26°C to 282°C, and up to 295°C for short periods; special formulations can reach -60°C.

Dynamic Sealing: Due to the generation of friction during movement, the temperature range is usually narrowed to -15°C to 280°C, and needs to optimize heat dissipation design for high temperatures.

5. Performance Focus

Static Sealing:

Core indicators: Leakage rate, compression permanent deformation, resistance to medium.

Advantage of fluororubber: Long-term resistance to high temperatures, resistance to chemical corrosion, suitable for high-pressure and highly corrosive environments.

Dynamic Sealing:

Core indicators: Friction coefficient, wear rate, dynamic response speed.

Challenges of fluororubber: The wear resistance is better than most rubbers but not as good as polytetrafluoroethylene (PTFE). Surface treatment or composite materials are needed for improvement.

Prioritize static sealing: If the components have no relative motion and need to be resistant to high temperatures and chemical corrosion (such as chemical pipelines, reaction vessels).

Be cautious with dynamic sealing: If there is rotation or reciprocating motion, evaluate the combined working conditions of temperature, speed, and pressure. Fluororubber dynamic seals are suitable for medium and low-speed, medium-high temperature scenarios; for high-speed or extreme temperatures, other materials (such as perfluororubber, PTFE) need to be considered.

Non-contact dynamic sealing: If sensitivity to friction is required (such as precision instruments), a composite structure with fluororubber auxiliary sealing can be selected.

FOREVER SEALS! Seals manufacturer, accept custom seals, from design to research and development, from production to testing, a full range of services. For more information, please contact FOREVER SEALS directly. FOREVER SEALS product experts are here to help you! Whatsapp: +86-18098184099；WeChat: +86-13049188460；  E-mail: sales@foreverseals.com