TDW’s PIG-SIG® IV Scraper Passage Indicator is a device installed on a pipeline to detect the passage of a pig or sphere. The most common indicators have a trigger extending into the pipeline through a welded fitting that has been tapped. When a pig passes, the trigger is tripped, activating the signaling mechanism.
Signaling systems available include a flag indicator, electrical indicator or flag/electrical indicator. All indicators are compatible with all standard plug assemblies now in the field and are interchangeable. This makes it possible to use these units as conversion kits as well as complete PIG-SIG® Indicators.