Common valves end connections include flanged, threaded, butt weld, and socket weld. Proper selection considers application pressure ratings, temperatures, corrosion allowances, piping layouts, line sizes, and maintenance requirements.
1. Flanged Connections
Flanging eases valve installation, removal, and maintenance while permitting interchangeability between the same flange standards. Major flange sealing faces per ASME B16.5 include flat face (FF), raised face (RF), ring type joint (RTJ), tongue & groove (TG), and male & female (MF). RTJ flanges suit high-pressure applications above Class 900.
The flanged end valve follows ASME flange dimensions and bolting specs. API-designated valves adhere to ASME oil and gas line flanges e.g. Classes 150, 300, 600, etc. For steel piping, higher classes suit higher pressures and temperatures - Class 150 for mixed services while Classes 300-2500 handle high-pressure steam, hydrocarbons, etc.
Cast/ductile iron flanges like Class 125 and 250 have identical dimensions to Class 150/300 steel flanges, only with FF faces and lower pressure-temperature ratings. Ductile iron handles greater stresses with twice the strength and flexibility of cast iron.
Between flange standards, bolting and gasket must be correctly chosen to avoid leakage. Wafer and lugged valves are also flange-connected.
2. Butt Weld Connections
Butt weld end (BWE) valves have pipe-like ends for aligning valve and piping bores. BYW connections efficiently convey pressure without losses, suiting high-integrity services. Their inherent strength and leak-tight sealing suit stringent temperature, pressure, and cyclic services in liquids, gases, steam, and hazardous corrosive fluids.
On high alloy piping, matching valve/pipe materials prevent galvanic corrosion. BWE valve suit automated orbital welding for optimal, consistent welds. For easy welding access, 6 o'clock bottom valve installations are preferred.
3. Socket & Threaded Connections
Thru-conduit gate/globe valve often use threaded end (TSE) and socket weld end (SWE) up to 2", with molded gaskets/sealants securing joints. However, both have lower pressure ratings than flanges and lack flexibility for frequent maintenance. Socket welds suit manual arc processes.
As threaded joints depend on operator skill and gasket sealing, these cannot be used for toxic, hazardous, or cycling services. Pipe threads are tapered to either 55° or 60° and are not interchangeable. For combustible or highly hazardous services under 3⁄4", threads require post-sealing.
At Vigor Valves Solutions, we understand that properly specifying end connections is vital for optimal performance, safety, and reliability. our team has delivered best-fit connection solutions to match client requirements across diverse field applications. please contact us at info@vigorpetroleum.com.
