Abstract: A device for indicating the passage of a pig beyond a predetermined location in a pipeline comprising a pig detector connected to a pipeline and communicating with the interior of the pipeline through an opening at the location. The device may comprise a trigger mounted in the pig detector and adapted to project into the interior of the pipeline, catch fingers mounted in the housing for movement toward and away from the central axis of the housing, a catch spring for urging the fingers towards the central axis, an attachment housing for attachment of the lower end of a push/pull extension cable for communicating with the trigger and an indicator, an upper housing for attachment of the upper end of the extension cable to the indicator, the indicator being slidably mounted within an indicator housing, and an indicator spring mounted within the indicator housing for urging the indicator beyond the indicator housing so as to be visible and to provide an indication that a pig has passed.

Abstract: A device for indicating the passage of a pig beyond a predetermined location in a pipeline comprising a pig detector connected to a pipeline and communicating with the interior of the pipeline through an opening at the location. A means for divorcing the pressure inside the pipeline from the pressure outside the pig. A trigger mounted in the pig detector and adapted to project into the interior of the pipeline through the opening, an indicator associated with the pig detector, a cylindrical indicator being slidably mounted within the indicator housing, catch fingers mounted in the housing for movement toward and away from the central axis of the housing, a catch spring for urging the fingers towards the central axis, an indicator spring mounted within the housing for urging the indicator beyond the indicator housing so as to be visible and to provide an indication that a pig has passed.