An instrument serves to insert a shuttle into a circuit for circulating a coating product. A chamber for receiving the shuttle, formed in a non-magnetic body is sized for receiving the shuttle in a position where axis of polarization thereof is parallel to a longitudinal axis of the chamber. A mouth connects the chamber to a first end of the body. A control lever equipped with at least two magnets is movable with respect to the chamber between a first position wherein a first magnet is aligned with the longitudinal axis, with a pole oriented towards the chamber having a first polarity, and a second position wherein the second magnet is aligned with the longitudinal axis, with a pole oriented towards the chamber having a second polarity opposite the first polarity.

A pipeline pig includes a main body with a conduit extending therethrough which defines a conical inlet converging to a throat and a conical outlet diverging from the throat such that the conduit is venturi-shaped. The pig further includes turbine blades disposed in the conical outlet about a longitudinal axis of the conduit and one or more scraper heads. When the pig is disposed within the pipe, the longitudinal axis of the conduit is parallel to and coincident with a longitudinal axis of the pipe, and, as a fluid flowing in the pipe pushes the pig through the pipe, at least a portion of the fluid flows into the conduit and through the throat and thence across the turbine blades, thereby imparting rotation on the one or more scraper heads as the scraper heads scrape the interior wall of the pipe.