Device and method for launching and/or retrieving pipeline scrapers

In a device for launching and/or retrieving a pig for cleaning out a fluid-conveying pipeline, the combination of:

• a housing structure forming (1) coaxial inlet and outlet ports for incorporation of the housing structure in the pipeline, (2) a valve chamber between the two ports and (3) a pig magazine dimensioned to house the pig and opening onto the valve chamber with the axis of the magazine extending laterally of the two ports;
• a valve member in the valve chamber and cooperating therewith to form a continuous flow passage between the inlet and outlet ports;
• a passage through the valve member,
• one end of said passage being a cavity to hold the pig;
• means at the opposite end of the passage to prevent escape of the pig therethrough whle permitting fluid flow therethrough between the two ports,
• said valve member being rotatable about an axis perpendicular to the axis of the two ports in a plane of rotation that includes the axis of the magazine and the axes of the two ports to permit rotating said cavity into register with the magazine and at least one of the two ports selectively;
• a normally closed closure for the magazine to permit access to the magazine from the exterior of the housing structure;
• and
• a valve seat forming a flow passage between the magazine and the valve chamber and being cooperative with the valve member to seal off the magazine from the valve chamber.