Which type of seal is commonly used in hydraulic fittings to prevent leaks?

• A. Flat gasket
• B. O-ring seal
• C. Thread seal tape
• D. Silicone sealant

Answer: (B)

The O-ring seal is commonly used in hydraulic fittings primarily due to its effectiveness at creating a reliable barrier against fluid leakage. O-rings are circular in shape and typically made from rubber or other elastomeric materials, allowing them to compress and form a tight seal when installed in a groove between two surfaces. This design enables the O-ring to handle pressure variations and movement in hydraulic systems, making it highly reliable for use in various hydraulic applications.

Moreover, O-rings can accommodate the thermal expansion and contraction of the fluid and the materials they're sealing against, which is crucial in hydraulic systems that operate under varying temperature conditions. Their ease of installation, low cost, and ability to be used in different sizes and materials further contribute to their widespread adoption in hydraulic fittings.