Engineering inside often uses two single ball valves replace double ball valve is because maintenance more flexible, single valve failure can alone replace, stopping machine
Double ball valve suitable for needs double isolation’s working conditions, like oil gas conveying pressure ≥4MPa or toxic medium pipeline, often used for maintenance venting
Ball valve leaving factory qualified but on-site leakage often due to installation stress leads to valve body deformation >0.3mm, actuator torque amplified 20% damages seal
Installation actuator after valve leakage mostly due to torque setting error (deviation >10%), valve stem coaxiality offset >0.5mm or not reset stroke limit, suggest re-calibrate
Installing ball valve when need guarantee pipeline coaxiality deviation ≤ 1mm, flange parallelism error ≤ 0.2°, avoid forced alignment produce stress; Sealing face installation before
Ball valve before installation should check specification and pressure grade, perform appearance and sealing face inspection and use 0.5MPa air pressure pre-test no leakage, clean
Ball valve field installation needs to ensure horizontal or vertical direction deviation is less than 1°, flange bolts according to diagonal divided into 3 times
The manufacturer conducts a fire test on API 6D ball valves according to API 607, pressurizing the valve to 75% of the rated pressure, burning
For API 6D ball valves to undergo API 607 fire resistance testing, design drawings, material certificates (EN10204 3.1), pressure rating and dimensional data, test procedures,
Adopt metal + soft seal dual structure, after fire burn metal seal leakage ≤ 100 ml/min;Packing select graphite withstand temperature ≥ 700℃;Valve seat add spring
