High temperature electromagnetic acoustic transducer (EMAT) probe and coil assemblies

An electromagnetic acoustic transducer (EMAT) probe assembly for producing an ultrasonic pulse in a workpiece, comprising:

• magnet means for producing a magnetic field in the workpiece;
• frustoconical focus core means, made of a material having a high magnetic permeability and connected to the magnet means, for focusing the magnetic field at a surface of the workpiece;
• coil assembly means located proximate to an end of the frustoconical focus core means distal from the magnet means, for producing eddy currents at the surface of the workpiece which interact with the focused magnetic field to produce the ultrasonic pulse in the workpiece, the coil assembly means having a coil disk made of high temperature dielectric material having at least one matrix of holes through the coil disk and grooves on surfaces of both sides of the coil disk which will permit at least one bare, continuous piece of electrically conductive wire to be threaded through and interwoven into the coil disk to produce at least one eddy current coil pattern of a desired configuration on the coil disk while preventing the at least one wire from contacting and shorting against itself, and at least one bare, continuous piece of electrically conductive wire threaded through and interwoven into the coil disk to produce the at least one eddy current coil pattern of the desired configuration on the coil disk;
• and
• ferromagnetic, cup-shaped probe assembly means having an end cap and a barrel for carrying the coil assembly means, the magnet means and the frustoconical focus core means, wherein the magnet means is located within the barrel and connected to the end cap, the cup-shaped probe assembly means positions the coil assembly means proximate the surface of the workpiece, and wherein the cup-shaped probe assembly serves to provide a return path for magnetic flux of the magnetic field back to the magnet means.

An electromagnetic acoustic transducer (EMAT) probe assembly for producing an ultrasonic pulse in a workpiece, comprising:

• magnet means for producing a magnetic field in the workpiece;
• frustoconical focus core means, made of a material having a high magnetic permeability and connected to the magnet means, for focusing the magnetic field at a surface of the workpiece;
• coil assembly means located proximate to an end of the frustoconical focus core means distal from the magnet means, for producing eddy currents at the surface of the workpiece which interact with the focused magnetic field to produce the ultrasonic pulse in the workpiece;
• an aluminum disk to which the coil assembly means is attached and heat conductive supporting means for supporting and conducting heat away from the aluminum disk and the coil assembly means;
• and
• ferromagnetic, cup-shaped probe assembly means having an end cap and a barrel for carrying the coil assembly means, the magnet means and the frustoconical focus core means, wherein the magnet means is located within the barrel and connected to the end cap, the cup-shaped probe assembly means positions the coil assembly means proximate the surface of the workpiece, and wherein the cup-shaped probe assembly means serves to provide a return path for magnetic flux of the magnetic field back to the magnet means.

An electromagnetic acoustic transducer (EMAT) probe assembly for producing an ultrasonic pulse in a workpiece, comprising:

• magnet means for producing a magnetic field in the workpiece;
• frustoconical focus core means, made of a material having a high magnetic permeability and connected to the magnet means, for focusing the magnetic field at a surface of the workpiece;
• an aluminum disk to which the coil assembly means is attached and heat conductive supporting means for supporting and conducting heat away from the aluminum disk and the coil assembly means, the heat conductive supporting means including a plurality of aluminum rods removably connected to the aluminum disk and the cup-shaped probe assembly means;
• and
• ferromagnetic, cup-shaped probe assembly means having an end cap and a barrel for carrying the coil assembly means, the magnet means and the frustoconical focus core means, wherein the magnet means is located within the barrel and connected to the end cap, the cup-shaped probe assembly means positions the coil assembly means proximate the surface of the workpiece, and wherein the cup-shaped probe assembly means serves to provide a return path for magnetic flux of the magnetic field back to the magnet means.

An electromagnetic acoustic transducer (EMAT) probe assembly for producing an ultrasonic pulse in a workpiece, comprising:

• magnet means for producing a magnetic field in the workpiece;
• frustoconical focus core means, made of a material having a high magnetic permeability and connected to the magnet means, for focusing the magnetic field at a surface of the workpiece;
• coil assembly means located proximate to an end of the frustoconical focus core means distal from the magnet means, for producing eddy currents at the surface of the workpiece which interact with the focused magnetic field to produce the ultrasonic pulse in the workpiece;
• ferromagnetic, cup-shaped probe assembly means having an end cap and a barrel for carrying the coil assembly means, the magnet means and the frustoconical focus core means, wherein the magnet means is located within the barrel and connected to the end cap, the cup-shaped probe assembly means positions the coil assembly means proximate the surface of the workpiece, and wherein the cup-shaped probe assembly means serves to provide a return path for magnetic flux of the magnetic field back to the magnet means;
• and
• a layer of fiberglass insulating material which covers a face of the coil assembly means that would be proximate the workpiece when the EMAT probe assembly is used to produce an ultrasonic pulse in the workpiece, the layer of fiberglass insulating material being secured in between the barrel and an end piece connected to the barrel.

An electromagnetic acoustic transducer (EMAT) probe assembly for producing an ultrasonic pulse in a workpiece, comprising:

• magnet means for producing a magnetic field in the workpiece;
• frustoconical focus core means, made of a material having a high magnetic permeability and connected to the magnet means, for focusing the magnetic field at a surface of the workpiece;
• ferromagnetic, cup-shaped probe assembly means having an end cap and a barrel for carrying the coil assembly means, the magnet means and the frustoconical focus core means, wherein the magnet means is located within the barrel and connected to the end cap, the cup-shaped probe assembly means positions the coil assembly means proximate the surface of the workpiece, wherein the cup-shaped probe assembly means serves to provide a return path for magnetic flux of the magnetic field back to the magnet means;
• and
• spring-loaded plunger means in the barrel to balance the magnetic attractive force of the magnet means and reduce the force required to remove the EMAT probe assembly from the workpiece.