Abstract: A metallic thermocouple probe is capable of withstanding temperatures in excess of 1650.degree. C. in oxidizing environments. First and second electrically conductive leads of dissimilar metals are joined at an extreme sensing end and extend to a distant readout device. Metal oxide insulation such as beryllium oxide, magnesium oxide, and aluminum oxide, electrically isolates the conductive leads and thermally isolates them from the environment. The extreme sensing end of the thermocouple probe is encapsulated to render it impermeable to the formation of oxides thereon. This encapsulation includes a protective coating composed of a non-porous ceramic material, preferably a cementation applied disilicide. Additionally, a high temperature structural sheath overlies the insulation adjacent the extreme sensing end and a low temperature sheath overlies the insulation adjacent the first sheath distant from the extreme sensing end.

Abstract: A transducer for measuring vibrations is formed of a case with a vibratory element mounted therein by means of a disk spring which is constrained to vibrate with the vibratory element in a single direction. Optical or magnetic sensors are located in registration with opposed ends of the vibratory element to produce optically or magnetically induced signals having a modulation thereon resulting from vibration of the vibratory element. The use of pairs of the sensors improves signal-to-noise ratio while allowing for increased bandwidth of the transducer in the measurement of vibration.

Abstract: A laser welder fault detector system, including a microphone and an associated electronic circuit operatively connected to a solenoid actuated ink jet, is provided to detect the formation of defective welds by an intermittently energized laser and to spray ink on sheets of metal being welded to mark the location of the defective welds. Defective welds are detected by acoustic signals generated during the welding process and picked up by the microphone, the amplitude of the signals, when defective welds are being formed, being relatively low compared to those generated when normal welds are being produced. The electronic components of the system compare the acoustic signals generated during the welding process with a reference signal characteristic of the formation of a normal weld.