Pig passage indicators – commonly referred to as “PIG-SIGs,” a term TDW originated more than 60 years ago – accurately detect pigs, spheres, scrapers, and other tools as they pass distinct points along the pipeline.
Not only do pig passage indicators provide information about the general location of an operator’s pig, they can also alert if a pig is lost or stuck. In addition, pig passage indicators installed at the end of the pipeline section notify when a pig has reached the receiver.
TDW offers three pig passage indictors: the PIG-SIG® V pig passage indicator, PIG-SIG NI non-intrusive pig passage indicator, and PIG-SIG IV pig passage indicator. Each is easily installed, removed, or replaced without pipeline shutdown.
Best used for: onshore or topside detection of pig passage through the pipeline, from launcher to receiver.
- Designed to withstand harsh conditions inside and outside the pipeline.
- Equipped with flag indicator, electrical indicator, or a combination of both.
- Available in extended models for installation on buried pipelines.
- The PIG-SIG NI non-intrusive pig passage indicator is easily banded onto the line, with no tapping required.
- Units equipped with an electrical indicator can be wired into your supervisory control and data acquisition (SCADA) system, and can be monitored in conjunction with other activities on the pipeline.
- All components exposed to pipeline products are completely sealed to prevent leaks.
- How do pig passage indicators work? Most pig passage indicators are equipped with a trigger mechanism that enters the pipeline through a tapped welded fitting or nipple. When a pig passes an indicator, the trigger is tripped, activating the signal. There is no tapping required for the PIG-SIG NI non-intrusive pig passage indicator, which uses high-strength, rare-earth, permanent trip magnets to trip the trigger.
- Are TDW pig passage indicators appropriate for operating in remote areas? Yes. Among the options available on the PIG-SIG NI non-intrusive pig passage indicator is enhanced long-distance viewing and SatCom satellite uplink, which electronically transmits pig passage information.