Safety Pig laucher and receiver for natural gas pipline cleaning
Description:
Launcher:
- Pipeline operator should make sure that the isolation valve and kicker valve are closed.
- If the system is a liquid system then the drain valve and vent valve should then be opened to allow air to displace the liquid; if the system is a gas system then the vent should be opened so that the launcher reaches atmospheric pressure.
- After the PIG launcher is completely drained to 0 psi, with the vent and drain valves still open, the trap door should then be opened.
- The PIG should then be loaded with its nose in contact with the reducer.
- Closure seals and other sealing surfaces should be cleaned and lubricated as needed and then the trap door should be closed and secured.
- The drain valve is then closed and the trap is slowly filled by gradually opening the kicker valve.
- Once filling is complete the vent valve is closed so that the pressure will equalize across the isolation valve.
- The isolation valve is then opened and the PIG is ready for launching.
- Next the main valve is gradually closed, increasing the flow through the kicker and behind the PIG until finally the PIG leaves trap altogether and enters the pipeline itself.
- After the PIG leaves the launcher the mainline valve is fully opened and the isolation valve and kicker valve are closed.
Receiver:
- The receiver should be pressurized.
- The bypass valve should be fully opened.
- The isolation valve should be fully opened and the mainline valve partially closed.
- Once the PIG arrives the isolation and bypass valves should be closed.
- The drain valve and vent valve are then opened.
- Once the trap is fully depressurized to 0 psi the trap can be opened and the PIG removed.
- The closure seal and other sealing surfaces should be cleaned and lubricated as needed and the trap door should then be re-shut and secured.
- The receiver should then be repressurized and returned to its original condition.
