Why is an ORB fitting often preferred over a tapered thread fitting?

An ORB (O-Ring Boss) fitting is often preferred over a tapered thread fitting primarily because it causes less stress and distortion in the connection. The design of an ORB fitting incorporates a flat sealing surface that connects with a matched O-ring, providing a more uniform distribution of load during assembly. This flat surface minimizes the risk of damage to the threads and reduces the likelihood of misalignment, which can occur with tapered threads as they rely on the threads themselves for sealing.

Tapered thread fittings can experience varying degrees of stress depending on how tightly they are torqued, and they can distort more significantly under pressure. This distortion can lead to a compromised seal and increase the potential for leaks. In contrast, ORB fittings, relying on the O-ring, can accommodate movement and thermal expansion without distorting the connection. This characteristic ensures reliability and can be particularly beneficial in high-pressure hydraulic systems where consistent performance is critical.

The advantages of ORB fittings also contribute to overall system integrity and longevity, as they help maintain the desired sealing performance over time compared to tapered threads. While other options may suggest ease of installation or reduced fluid leakage, the primary reason for the preference is indeed the minimized stress and reduced risk of distortion associated with the connection.