Abstract: A pipeline pig includes a central body member, a plurality of circumferentially spaced return path elements surrounding said body member and each extending axially relative to the body member, each return path element including a pair of axially spaced magnets from each of which projects a metallic bristle set, and means for connecting the return path elements to the body member whereby the free ends of the bristles, in use, resiliently engage the inner wall of the pipeline, the connecting means comprising a first carrier member mounted on, to be axially slidable relative to, the front extent of the body member and resiliently urged towards the rear of the body member, a second carrier member mounted on, to be axially slidable relative to, the rear extent of the body member and resiliently urged towards the front of the body member, and, for each return path element, a front link pivotally interconnecting the front of the return path element and the first carrier member, and a rear link pivotally interconnect

Abstract: A pipeline pig comprises a central body member and a first drive member (26) mounted on the body member, the first drive member including a central annular support element (60) mounted on, to surround, the body member, and a plurality of circumferentially spaced primary drive elements (62) one end of each of which is secured to the support element (60) whereby the primary drive elements (62) extend substantially radially from the support element (60) and such that, in use, the other, free ends of the primary drive elements (62) engage the inner wall of the associated pipeline, each primary drive element (62) being capable of bending rearwardly of the direction of movement of the pig about the one end extent thereof to maintain engagement with the inner wall of pipelines within a range of diameters without increasing the drag thereon, the first drive member (26) further including a flexible backing disc (68) rearward of the primary drive elements (62) and adapted to seal against the inner wall of the pipeline

Abstract: A pipeline pig includes a central body member, a plurality of circumferentially spaced return path elements surrounding said body member and each extending axially relative to the body member, each return path element including a pair of axially spaced magnets from each of which projects a metallic bristle set, and means for connecting the return path elements to the body member whereby the free ends of the bristles, in use, resiliently engage the inner wall of the pipeline, the connecting means comprising a first carrier member mounted on, to be axially slidable relative to, the front extent of the body member and resiliently urged towards the rear of the body member, a second carrier member mounted on, to be axially slidable relative to, the rear extent of the body member and resiliently urged towards the front of the body member, and, for each return path element, a front link pivotally interconnecting the front of the return path element and the first carrier member, and a rear link pivotally interconnect

Abstract: A pipeline pig comprises a body and at least one flexible annular outwardly extending seal on and around the body for sealingly contacting a pipeline interior wall under differential fluid pressure whereby to propel the pig along the pipeline. The pig also comprises a fluid bypass duct arrangement extending through the body and resilient frictional bristles on and extending from the body adapted to contact the pipeline interior wall and exert a drag on the pig. An adjustable bypass flow control unit is provided which is adapted to regulate fluid flow through the duct arrangement and thus the speed of the pig.