초록 ▼

An internal inspection unit for pipe has ultrasonic transducers that inspect weld volume, weld root, and wall thickness. The ultrasonic transducers are mounted to a portion of the inspection unit that is rotatable, but no more than one full revolution. One of the units has independently movable shoe

An internal inspection unit for pipe has ultrasonic transducers that inspect weld volume, weld root, and wall thickness. The ultrasonic transducers are mounted to a portion of the inspection unit that is rotatable, but no more than one full revolution. One of the units has independently movable shoes for each separate transducer. The shoes are moved between retracted and extended positions by pneumatic cylinders. The other unit has shoes that support more than one transducer, the shoes being biased outwardly by springs.

대표청구항 ▼

1. A method of inspecting a pipe, comprising:(a) mounting an inspection unit to a frame and mounting to the inspection unit a first ultrasonic transducer for determining wall thickness of a pipe and second and third ultrasonic transducers axially spaced apart from each other relative to a longitudin

1. A method of inspecting a pipe, comprising:(a) mounting an inspection unit to a frame and mounting to the inspection unit a first ultrasonic transducer for determining wall thickness of a pipe and second and third ultrasonic transducers axially spaced apart from each other relative to a longitudinal axis of the unit for inspecting weld volume defects; (b) inserting the unit with the first, second and third ultrasonic transducers mounted thereto into a pipe and conveying the unit along the pipe; (c) periodically causing the first ultrasonic transducer to emit an acoustical signal into a wall of the pipe and detecting a return acoustical signal from the pipe and thereby determining wall thickness of the pipe; and (d) positioning the unit in a position that places the second and third ultrasonic transducers on opposite sides of a weld that extends circumferentially around the pipe, then rotating the second and third ultrasonic transducers relative to the frame about the axis of the unit and simultaneously causing the second ultrasonic transducer to emit an acoustical signal into the weld and receiving a return acoustical signal with the third ultrasonic transducer, to determine if a volume of the weld has any defects. 2. The method according to claim 1, wherein step (a) further comprises:prior to step (b), mounting fourth and fifth ultrasonic transducers to the inspection unit for inspecting a root of the weld; and step (d) further comprises: placing the fourth and fifth ultrasonic transducers on opposite sides of the weld simultaneously with the second and third ultrasonic transducers, rotating the fourth and fifth ultrasonic transducers relative to the frame about the axis of the unit and simultaneously causing each of the fourth and fifth ultrasonic transducers to emit an acoustical signal and receive an acoustical signal from a root of the weld to determine if the root of the weld has any defects. 3. The method according to claim 2, wherein the fourth and fifth ultrasonic transducers are rotated simultaneously with the second and third ultrasonic transducers.4. The method according to claim 1, further comprising stopping movement of the inspection unit along the pipe while performing step (c).5. The method according to claim 1, wherein step (c) further comprises:predetermining a plurality of inspection areas at selected lineal increments along the pipe and a plurality of inspection sites circumferentially around the pipe at each inspection area; stopping movement along the pipe at each inspection area, then rotating the inspection unit relative to the frame about the axis of the frame; and automatically collecting the data at each inspection site while the inspection unit is rotated. 6. The method according to claim 1, wherein step (d) comprises rotating the second and third ultrasonic transducers less than one full revolution in one direction at a first weld, then rotating the second and third ultrasonic transducers back less than one full revolution in the opposite direction at a next weld.7. The method according to claim 1, wherein the unit is stopped from movement along the pipe and the second and third ultrasonic transducers rotated less than one full revolution while step (d) is being performed.8. A method of inspecting a pipe, comprising:(a) providing a self-propelled drive unit having a longitudinal axis; (b) mounting an inspection unit on the drive unit for rotation about the longitudinal axis, the inspection unit having a first ultrasonic transducer for determining a wall thickness of a pipe, second and third ultrasonic transducers spaced axially from the first ultrasonic transducer for detecting any flaws in a volume of a weld, and fourth and fifth ultrasonic transducers for detecting flaws in a root of the weld, the fourth and fifth ultrasonic transducers being spaced the same axial distances from the first ultrasonic transducer as the second and third ultrasonic transducers, but circumferentially offset, each of the transducers being mounted to a separate shoe that is movable between a retracted position and an extended position; (c) stopping the unit within the pipe in a position that places the second and third ultrasonic transducers on opposite sides of a weld and the fourth and fifth ultrasonic transducers on opposite sides of the weld, causing the shoes that contain the second through fifth ultrasonic transducers to contact an inner diameter of the pipe, then rotating the inspection unit less than one full revolution; and (d) while rotating the inspection unit, causing the second ultrasonic transducer to emit an acoustical signal into the volume of the weld and receiving a return acoustical signal with the third ultrasonic transducer to inspect the volume of the weld; and (e) at the same time as step (e), causing the fourth ultrasonic transducer to emit an acoustical signal that reflects into the root of the weld, and receiving with the fourth ultrasonic transducers any acoustical signals resulting from any defects in the root of the weld, and causing the fifth ultrasonic transducer to emit an acoustical signal that reflects into the root of the weld and receiving with the fifth ultrasonic transducer any acoustical signals resulting from any defects in the root of the weld; and (f) moving the inspection unit linearly within the pipe, moving the shoe containing the first ultrasonic transducer to an extended position in contact with the inner diameter of the pipe and causing the first ultrasonic transducer to periodically emit an acoustical signal into the pipe and detecting a return acoustical signal to determine wall thickness. 9. The method according to claim 8, wherein step (f) is performed at selected inspection areas along the pipe, and comprises stopping the inspection unit at the selected inspection areas and rotating the inspection unit at each inspection area less than one full revolution.10. The method according to claim 9, further comprising preprogramming a selected number of inspection sites around a circumference of the pipe at each inspection area, and without stopping rotation of the inspection unit, automatically computing a wall thickness when the first transducer passes each of the inspection sites.11. The method according to claim 8, further comprising placing the first ultrasonic transducer in a retracted position while performing steps (c)-(e) and the placing the second through fifth transducers in retracted positions while performing step (f).12. The method according to claim 8, wherein step (b) further comprises mounting each of the transducers within a recess of a shoe, steps (c)-(e) further comprise flowing a liquid through each recess containing the second through fifth ultrasonic transducers, and step (f) further comprises flowing a liquid through the recess containing the first ultrasonic transducer.13. An apparatus for inspecting pipe, comprising:an inspection unit having an axis; a first ultrasonic transducer carried by the inspection unit for emitting and receiving acoustical signals to determine a wall thickness of the pipe; second and third ultrasonic transducers carried by the inspection unit along with the first ultrasonic transducer for emitting and receiving acoustical signals through a volume of a weld in the pipe; fourth and fifth ultrasonic transducers carried by the inspection unit along with the first, second and third ultrasonic transducers, each for emitting acoustical signals and receiving acoustical signals that pass through a root portion of the weld; and the second through fifth ultrasonic transducers being mounted for selective rotation about the axis of the inspection unit no more than one full revolution while emitting acoustical signals into and receiving acoustical signals from the weld. 14. The apparatus according to claim 13, further comprising a plurality of shoes to which the transducers are mounted, the shoes being urged radially outward from the axis for engaging an inner diameter of a pipe.15. The apparatus according to claim 14, further comprising a plurality of recesses in outer surfaces of the shoes into which the transducers are mounted; anda plurality of passages for delivering a coupling liquid to the recesses. 16. The apparatus according to claim 13, further comprising a plurality of shoes that are movable independently of each other in radial directions, each of the transducers being mounted to one of the shoes, the shoes being urged radially outward from the axis for engaging an inner diameter of a pipe.17. An apparatus for inspecting pipe, comprising:an inspection unit having an axis; a first ultrasonic transducer carried by the inspection unit for emitting and receiving acoustical signals to determine a wall thickness of the pipe; second and third ultrasonic transducers carried by the inspection unit for emitting and receiving acoustical signals through a volume of a weld in the pipe; fourth and fifth ultrasonic transducers carried by the inspection unit, each for emitting acoustical signals and receiving acoustical signals that pass through a root portion of the weld; and the second through fifth ultrasonic transducers being mounted for selective rotation about the axis of the inspection unit no more than one full revolution while emitting acoustical signals into and receiving acoustical signals from the weld;a plurality of shoes that are movable independently of each other in radial directions, each of the transducers being mounted to one of the shoes, the shoes being urged radially outward from the axis for engaging an inner diameter of a pipe; a pneumatic cylinder mounted to each of the shoes; and a first valve that selectively causes the pneumatic cylinders to move the shoe containing the first ultrasonic transducer between retracted and extended positions; and a second valve that operates independently of the first valve for moving the shoes containing the second through fifth transducers between retracted and extended positions. 18. The apparatus according to claim 13, further comprising:a drive unit onto which the inspection unit is mounted, the drive unit having a motor, a set of drive wheels driven by the motor and a set of support wheels that are spaced from the drive wheels and which freewheel; and an encoder operatively coupled to the support wheels for providing an indication of linear travel of the unit along the pipe in response to rolling movement of the support wheels. 19. The apparatus according to claim 13, wherein the first transducer is also mounted for rotation about an axis of the inspection unit less than one full revolution, and the apparatus further comprises:a rotational sensor mounted to the apparatus for providing an azimuth indication of the inspection unit as it rotates; and a controller connected to the drive unit and the rotational sensor, the controller having a pre-programmable selector for selecting inspection sites spaced selected degrees apart around the circumference of the pipe, the controller automatically collecting data from the first ultrasonic transducer upon passing each inspection site. 20. An apparatus for inspecting pipe, comprising:a frame having an axis and mounted on a set of drive wheels and a set of support wheels spaced axially from the drive wheels; a linear drive motor mounted to the frame and coupled to the drive wheels for moving the frame linearly along an interior of a pipe; an inspection unit mounted to the frame; a radial drive motor for rotating the inspection unit relative to the frame about an axis of the frame; a plurality of sets of shoes carried by the inspection unit and spaced circumferentially around the axis, each of the sets comprising at least two shoes spaced circumferentially apart from each other, the shoes within each of the sets being at the same axial position along the inspection unit, some of the sets being located at different axial positions from other of the sets; a plurality of pneumatic cylinders, each mounted to one of the shoes of the inspection unit perpendicular to the axis; at least one control valve coupled to the pneumatic cylinders for selectively moving the shoes radially outward to an extended position for engaging an inner diameter of the pipe and moving the shoes radially inward to a retracted position to facilitate entry of the inspection unit into the pipe; a plurality of recesses in outer surfaces of the shoes; a plurality of ultrasonic transducers mounted in the recesses for emitting and receiving acoustical pulses to determine a wall thickness of the pipe and detect defects in welds; and a plurality of passages in the shoes for delivering a coupling liquid to the recesses. 21. The apparatus according to claim 20 wherein the support wheels rotate freely; and wherein the apparatus further comprises:an encoder operatively coupled to the support wheels for providing an indication of linear travel of the unit along the pipe in response to movement of the support wheels. 22. The apparatus according to claim 20, wherein the inspection unit is cantilever mounted to one end of the frame.23. The apparatus according to claim 20, wherein said at least one control valve comprises two control valves, one of the control valves controlling some of the pneumatic cylinders independently of the other control valve to enable some of the shoes to be in the retracted position while others are in the extended position.24. An apparatus for inspecting pipe, comprising:an elongated frame having an axis and mounted on at least two sets of wheels; an inspection unit mounted to the frame intermediate forward and rearward ends of the frame, defining a forward frame portion and a rearward frame portion, with one of the sets of the wheels mounted to the forward portion and the other of the sets of wheels mounted to the rearward portion for rolling the frame horizontally along a pipe; a radial drive motor for rotating the inspection unit relative to the frame about the axis of the frame; a plurality of shoes spaced circumferentially around the axis, each of the shoes being elongated in an axial direction and urged radially outward relative to the inspection unit; a plurality of recesses in an outer surface of each of the shoes; a plurality of ultrasonic transducers mounted in the recesses for emitting and receiving acoustical pulses to determine a wall thickness of the pipe and detect defects in welds; and a plurality of passages in the shoes for delivering a coupling liquid to the recesses. 25. An apparatus for inspecting pipe, comprising:an elongated frame having an axis and mounted on at least two sets of wheels; an inspection unit mounted to the frame intermediate forward and rearward ends of the frame, defining a forward frame portion and a rearward frame portion, with one of the sets of the wheels mounted to the forward portion and the other of the sets of wheels mounted to the rearward portion; a radial drive motor for rotating the inspection unit relative to the frame about the axis of the frame; a plurality of shoes spaced circumferentially around the axis, each of the shoes being elongated in a axial direction and urged radially outward relative to the inspection unit; a plurality of recesses in an outer surface of each of the shoes; a plurality of ultrasonic transducers mounted in the recesses for emitting and receiving acoustical pulses to determine a wall thickness of the pipe and detect defects in welds; a plurality of passages in the shoes for delivering a coupling liquid to the recesses; and wherein the shoes are urged radially outward by springs. 26. The apparatus according to claim 24 further comprising an encoder operatively coupled to the wheels for providing an indication of linear travel of the unit along the pipe in response to movement of the wheels.27. An apparatus for inspecting pipe, comprising:a frame mounted on wheels; an inspection unit mounted to the frame; a radial drive motor for rotating the inspection unit relative to the frame about the longitudinal axis of the frame; a plurality of shoes carried by the inspection unit; a plurality of recesses in outer surfaces of the shoes; a plurality of passages in the shoes for delivering a coupling liquid to the recesses; a first ultrasonic transducer carried by a first one of the shoes for emitting and receiving acoustical signals to determine a wall thickness of the pipe; and second and third ultrasonic transducers carried by second and third ones of the shoes while the first one of the shoes is carrying the first ultrasonic transducer, for emitting and receiving acoustical signals through a volume of a weld in the pipe, the second and third shoes being axially spaced apart from each other for location on opposite sides of a weld.