Following are recommended procedures for receiving pigs in pipelines equipped with industry-standard receivers. Due to varying pig styles, receiver designs, pigging applications, pipe types, propelling media, internal conditions, and other factors, these procedures should not be considered absolutes. Please consult a pig manufacturer or distributor for technical assistance for your specific application.
(Refer to following diagram)
- Open bypass and isolation valves.
- Partially close main line valve.
- Monitor pig detector for pig reception.
- When pig is received, open main line valve.
- Close bypass and isolation valves.
- Open vent and drain valves.
- By checking pressure gauge for zero psi, ensure receiver is depressurized.
- Open closure.
- Remove pig.
- Close and secure closure.
Whether pig is to be used again or not, the pig should be inspected for satisfactory pig performance. By measuring the outer diameter of the pig with a diameter tape or using a regular tape and dividing by 3.1416, wear during pig run can be calculated. The pig's sealing surfaces should also be inspected for tears, cuts, uneven wear, punctures, and other damage, which may alert operator to damaging conditions in the line. Steel mandrel pigs with spring-loaded brushes should be inspected for corrosion, fatigue and breakage. Because loose brush pieces can damage valves and instrumentation in the pipeline, all components should be inspected to ensure they are intact.