Pipeline Pig Launcher and Receiver Valve Systems

Pipeline pigging requires special valve arrangements at launcher and receiver stations. These systems allow pigs to be inserted and retrieved safely while maintaining pipeline pressure integrity.

Pig Launcher and Receiver Configuration

A pig launcher consists of a mainline isolation valve, a barrel for pig loading, and kicker and equalizing valves. The receiver has similar components for safe pig retrieval.

• Mainline valve: Full-bore ball valve sized to pass the pig

• Barrel: Oversized pipe section (1.5x mainline diameter) to accommodate pig

• Kicker valve: Diverts flow through barrel to launch pig

• Equalizing valve: Pressurizes or depressurizes barrel before opening closure

• Drain valve: Removes liquid from barrel before opening closure door

Valve Types for Pig Systems

Full-bore valves are mandatory in pig systems. Ball valves are standard for mainline isolation, while globe and check valves serve auxiliary functions in the pigging station.

• Full-bore ball valve: Zero obstruction ensures pig passes without getting stuck

• Check valve: Prevents reverse flow during receiver operations

• Globe valve: Kicker, equalizing, and drain functions requiring throttling

• Pressure indicator: Required on barrel for safe pressure verification

Safety Requirements for Pig Systems

Pigging operations involve opening pressurized equipment. Safety interlocks prevent accidental opening of closures under pressure. Written procedures and operator training are mandatory.

• Pressure interlock: Barrel must be fully depressurized before closure opens

• Vent and drain: Verify zero pressure before attempting to open barrel door

• PIG IN BARREL indicator: Detects pig location to prevent premature launch

• Written SOP: Step-by-step procedure for each pigging operation

Intelligent Pigging Considerations

Intelligent (smart) pigs carry inspection instruments and require larger bore clearances. Launchers and receivers for intelligent pigging must accommodate the longer, heavier pig body.

• Bore clearance: Intelligent pigs require tighter tolerances in valve bore

• Barrel length: Extended barrel for multi-section intelligent pig trains

• Pressure and temperature: Smart pig electronics sensitive to extreme conditions

• Data retrieval: Receiver design must allow quick pig access for data download