These structures achieve static or dynamic seals through different design principles and material combinations.
1. O-ring
- Structural characteristics: Circular cross-section, installed in a groove, producing a sealing effect through compression deformation.
- Applications: Widely used for static and reciprocating motion seals in flanges, end caps, and pipe interfaces.
- Advantages: Simple structure, low cost, and high standardization.
- Precautions: A retaining ring is required under high pressure to prevent extrusion; double retaining rings are required for bidirectional pressure applications.
2. V-packing
- Structural composition: Consists of a support ring, a V-shaped sealing ring, and a pressure ring. Primarily used for reciprocating motion seals.
- Working principle: The V-shaped lip opens under pressure, achieving a "self-tightening" seal; the higher the pressure, the better the sealing effect.
- Applicable Operating Conditions: High pressure resistant (up to 60MPa and above), suitable for hydraulic cylinder and pneumatic cylinder piston rod seals.
- Installation Points: The V-shaped opening must face the pressure side; otherwise, seal failure will occur.
3. Combination Seals (e.g., Step seals, Glyd rings)
- Structure: Composed of a wear-resistant ring and an elastic O-ring, commonly found in high-pressure, high-precision pumps or plunger systems.
- Advantages: Combines good sealing performance and wear resistance, suitable for precision applications such as high-pressure metering pumps and dispensing equipment.
4. Gaskets and Flat Seals
- Structure Types: Includes flat gaskets and end-face sealing gaskets, commonly made of PTFE, nylon, or high-temperature resistant rubber.
- Application Locations: Pump covers, valve blocks, flange flat seals.
- Failure Symptoms: Crush, swelling, and corrosion leading to leakage.