ANSI B16.11 Threaded Half Coupling is a common pipeline fitting characterized by its simple structure, easy installation, corrosion resistance, and reliable sealing performance. As a result, it is widely used in various liquid and gas transportation systems.
Specification
Type: Half Coupling.
Size: 1/2 Inch (DN15).
Class: 3000LB.
End: NPT Female.
Material: ASTM A105.
Standard: ANSI B16.11.
Differences Between Half Couplings and Weldolet Fittings
Definition and Structural Differences
Half Coupling
Also known as "half pipe clamp" or "branch fitting," it is a pipe fitting used to create a branch connection from the main pipeline.
Features a semi-circular groove design, installed by welding or threading onto the main pipe, commonly used in low-pressure small-diameter pipelines (e.g., DN15-DN50).
Typical materials include carbon steel (ASTM A234) or stainless steel (ASTM A403), with a pressure rating generally ≤1.6 MPa.
Weldolet (Pipe Saddle)
Officially called "branch outlet" or "weldolet," it is used for branch connections in high-pressure or critical pipelines.
Constructed with integral forging or thick-wall welding, featuring reinforcement ribs, and can withstand pressures exceeding 10 MPa (e.g., per ASME B16.11 standard).
Widely used in the petroleum and chemical industries, with a broad size range (DN20-DN600).
Functional and Performance Comparison
Connection Strength
Half couplings rely on welding or threading for fixation, offering weaker vibration resistance; weldolets distribute stress through their full-wrap structure, providing superior seismic performance.
Sealing Performance
Half couplings require sealants or gaskets, making them prone to leakage; weldolets come with flanged or butt-weld ends, achieving sealing levels up to ANSI Class 600.
Maintenance Costs
Replacing half couplings requires cutting the main pipe, resulting in higher maintenance costs; weldolets feature a removable design, enabling quick repairs.
Application Scenarios
Scenarios Favoring Half Couplings
Temporary pipelines or low-pressure water systems (e.g., building water supply and drainage).
Budget-constrained projects with minimal maintenance requirements.
Scenarios Requiring Weldolets
High-temperature and high-pressure media (e.g., steam pipelines, refinery piping).
Applications where regulations mandate their use (e.g., ASME B31.3 Process Piping Code).
Additional Knowledge: Key Selection Parameters
Pressure Rating: Weldolets must match the system design pressure, e.g., SCH80 weldolets for PN4.0 MPa systems.
Compatibility: Half couplings are limited to use with pipes of the same material, whereas weldolets can connect different materials (e.g., carbon steel weldolets with stainless steel branch pipes).