Support olet is a special pipe fitting in industrial piping systems that integrates branch connection and diagonal support functions. It is also often referred to as a supported branch outlet or branch outlet with support, and is an optimized derivative of branch outlet fittings.It is mainly used in piping systems under high pressure, large diameter, high flow velocity or vibrating conditions to solve the problem that conventional branch outlets can only realize branch connection but cannot bear additional loads caused by branch medium pressure, dead weight and vibration, which easily leads to stress concentration and weld cracking at the connection between the main pipe and branch pipe.It is an integrated pipe fitting that combines branch connection, structural stress distribution and load support.
This fitting is integrally formed as a single piece of cast steel or forged steel, and mainly consists of three parts: the main pipe connection end, the branch pipe connection end, and the diagonal support arm.The main pipe connection end is designed as an arc-shaped saddle structure matching the outer wall of the main pipe, which can be firmly attached to the main pipe by welding to ensure the sealing and connection strength between the main pipe and the branch outlet.The branch pipe connection end is a straight pipe section with a flange or butt-weld bevel, which is directly connected or welded to the branch pipe to realize the branched delivery of the medium.The diagonal support arm is connected between the branch pipe connection end and the main pipe connection end at a fixed inclined angle (typically 45°, 60°, or customized according to the pipeline layout), forming a triangular support structure.This structure distributes and transfers the dead weight of the branch pipe, pressure loads from the medium, and dynamic loads generated by pipeline vibration through the support arm to the main pipe body, greatly reducing local stress concentration at the welded joint between the main pipe and the branch pipe.At the same time, it enhances the structural rigidity of the branch connection area, effectively preventing fatigue cracking of welds and deformation of fittings caused by excessive loads or vibration, thereby improving the overall stability of the piping system.
In terms of fabrication and installation, the main pipe connection end of the support olet must be precisely matched to the outer diameter and radius of curvature of the main pipe. Before welding, the contact surfaces shall be ground to ensure tight welding fit. During welding, the saddle weld between the main pipe and the support olet shall be welded first, followed by the connecting weld between the branch pipe and the support olet. Finally, the connection between the support arm and the main body shall be inspected, and non-destructive testing shall be performed after confirming no welding defects to ensure welding quality. During installation, the diagonal support arm must be positioned at the designed load-bearing angle, and the triangular support structure shall face the load direction of the branch pipe directly, so as to prevent the support arm from being subjected to shear force instead of compressive stress. Meanwhile, according to the thermal expansion and contraction characteristics of the pipeline, consideration shall be given to reserving a certain compensation gap to avoid additional stress on the support arm caused by thermal deformation.
Support olets have clearly targeted application scenarios. They are mainly used in high-pressure and large-bore process pipelines, reciprocating compressor pipelines with medium pulsation, pump inlet and outlet pipelines prone to vibration, heavy-load vertical branch pipelines, offshore platforms and other piping systems subject to severe vibration.Typical applications include hydrocracking and reforming unit pipelines in petroleum refining, high-pressure process medium transmission pipelines in chemical industrial parks, steam pipelines in power systems, and oil and gas transmission pipelines on offshore engineering platforms. They are especially suitable for conditions where the branch pipe diameter is relatively large and the diameter difference between the branch pipe and the main pipe is small, so that conventional branch outlets cannot bear the load.Support olets replace the traditional combination of “branch outlet + additional welded supports”, reducing on-site welding procedures and improving the efficiency and reliability of pipeline installation.Meanwhile, due to their compact overall structure and small space occupation, they are also suitable for narrow spaces with dense pipeline layouts.
Compared with conventional branch outlets, the core advantages of support olets lie in their integrated structure, excellent stress distribution and higher rigidity, which can effectively solve the problem of stress concentration at branch connections under high-load and high-vibration conditions. The disadvantages are that their cost is higher than that of conventional branch outlets, and they have stricter requirements for installation angle and pipeline layout. Pipeline stress calculation must be carried out in advance to determine the support angle and installation position. Therefore, they are only selected under working conditions where the load or vibration exceeds the bearing capacity of conventional branch outlets. For conventional branch connections under medium and low pressure, with small diameters and no obvious vibration, ordinary branch outlets are still preferred.
Compared with conventional branch outlets, the core advantages of support olets lie in their integrated structure, excellent stress distribution and higher rigidity, which can effectively solve the problem of stress concentration at branch connections under high-load and high-vibration conditions. The disadvantages are that their cost is higher than that of conventional branch outlets, and they have stricter requirements for installation angle and pipeline layout. Pipeline stress calculation must be carried out in advance to determine the support angle and installation position. Therefore, they are only selected under working conditions where the load or vibration exceeds the bearing capacity of conventional branch outlets. For conventional branch connections under medium and low pressure, with small diameters and no obvious vibration, ordinary branch outlets are still preferred.
