PIG-DEFECTOSCOPE WITH VARIABLE SPEED OF MOVEMENT Russian patent published in 2009 - IPC G01N27/87 

FIELD: physics; measurement.

SUBSTANCE: invention relates to devices for non-destructive detection of flaws in walls of main pipelines. The pig-defectoscope with variable speed of movement contains a cylindrical body, straps, fitted on the body, through-holes inside the body, odometres, computer control system, container with electrical power units and electronic equipment, gas bypass actuator, device for changing the cross section of the through-hole, magnets, attached to the cylindrical body, magnetic field sensors of the pipeline, and brushes-magnetic conductors, which are joined into sections. The pig-defectoscope is provided with axial displacement sensors in form of devices for measuring deformation of inner faces of the straps, deformation of the sections of brushes-magnetic conductors and variation of the diametre of the pipeline, arranged into a circle, numbering not less than four and not less than two rows of devices for measuring deformation of inner faces of the straps and deformation of the sections of brushes-magnetic conductors. The device is also provided with an airtight container at its rear part, two gas pressure receivers in form of Pitot tubes in the middle and rear parts, fixed on the front and rear containers, with inlet openings, respectively directed in the forward and opposite direction of movement of the device, orientation and navigation devices, computer model of the dynamics of the device in form of an extra computer, fitted in the front container. The device for changing the cross section of the through-holes is in form of an even number of immovable, as well as movable rotating blades. The inputs of the extra computer are connected to outputs of the corresponding devices for measuring deformation of straps, outputs of the devices for measuring displacement of sections of brushes-magnetic conductors, outputs of devices for measuring variation of the diametre of the pipeline, outputs the front and rear gas pressure receivers, odometre outputs, outputs of the device for measuring apparent acceleration, directed in the longitudinal axis of the pig, and the output of the angular sensor of the shaft of the electric motor and outputs of the extra computer are connected to inputs of the computer system for controlling the electric drive of the rotating blades.

EFFECT: increased accuracy of detecting flaw in main pipelines by increasing accuracy of measurement and stabilising speed of the pig, and simpler design of the flaw detector without loss of efficiency of gas bypassing.

4 cl, 9 dwg