US 4,320,344 A · Metal-alloy thermoelectric characteristic analyzer

Abstract

Apparatus for identifying the metal alloy composition of a test piece. Two thermoelectric probes are brought into contact with the test piece. Both of the probes are heated, one of which is heated to a predetermined temperature greater than the temperature of the other probe. The probes comprise electrodes of a thermally conductive material having in thermoelectric contact therewith, respective thermoelectric circuits having differing predetermined thermoelectric characteristics. A variable voltage divider electrically couples the respective thermoelectric circuits of the two probes. The output terminals of the voltage divider networks are connected in series opposition through a null meter or indicator which displays the test result. The voltage divider networks of the respective probes are mechanically or electrically slaved such that they are adjusted in synchronism, thereby desensitizing the apparatus to changes in test temperature, ambient temperature or the temperature of the respective test pieces. Further, simple calibration means are described and additionally, provisions for establishing further discriminants between alloys by (1) the use of different metal probe contact tips, (2) application of a magnetic field to encompass the probe/test piece junction, (3) momentarily varying the temperature of one of the electrodes through a Peltier effect, (4) generating biasing voltages across the probe/test junctions, and (5) comparing voltage-ampere ratio's of each alloy. One or a combination of such features may serve to alter and/or reveal thermoelectric characteristics for discriminating between alloys of similar chemical composition or to confirm the identity of known metal alloys or to establish positive identification of metals of unknown chemistry or to detect alloying segregation in high quality metal products.

Claims26

Dependent claims

Apparatus for providing indicia of the metal alloy composition of a test piece comprising:

first and second thermoelectric probes adapted for thermoelectrically contacting said test piece, each probe including an electrode, first and second thermoelectric circuits thermally coupled and electrically connected to said electrode, and a variable voltage divider electrically coupling said first and second thermoelectric circuits, said first and second thermoelectric circuits having different predetermined thermoelectric characteristics;
said apparatus further comprising means for adjusting the variable voltage divider of said first and second probes together in synchronism;
and
means for electrically coupling said variable voltage dividers in series opposition and for providing indicia of the relative adjustment of said variable voltage dividers.

1 more element

Apparatus for testing the metal alloy composition of a test piece, said apparatus being of the type including first and second thermoelectric probes for contacting said test piece and generating signals indicative of their respective thermoelectric interaction therewith, means for maintaining one of said probes at a predetermined temperature greater than the temperature of the other, and indicator means coupled to said first and second probes for providing indicia of the relative amplitude of said signals, wherein:

said first and second probes each include an electrode of a first thermally conductive material, a first conductor of a second material and a second conductor of a third material, respectively coupled to said electrode and forming first and second thermoelectric junctions therewith, said first and second thermojunctions generating first and second thermoelectric potentials, respectively;
and a third conductor of said first material coupled to said electrode;
first, second and third voltage variable divider means, for generating, at an output terminal thereof, a signal indicative of a controlled fraction of the potential difference between first and second input terminals thereof, said first voltage divider means first and second input terminals being connected to said first conductor and said third conductor respectively and said second voltage divider means first and second input terminals being connected to said second conductor and third conductor respectively;
said third voltage divider means first and second input terminals being connected to said first voltage divider means output terminal and said second voltage divider means output terminal, respectively;
and said first and second probe third voltage divider output terminals being coupled to said indicator means, electrically coupling said probes in series opposition;
said apparatus further comprising means for adjusting said first and second probe first voltage divider means in synchronism;
means for adjusting said first and second probe second voltage divider means in synchronism;
and
means for adjusting said first and second probe third voltage divider means in synchronism.

6 more elements

said first and second probes each include an electrode of a first thermally conductive material, a first conductor of a second material, a second conductor of a third material and a third conductor of said first material,
said first and second and third conductors being electrically coupled to one another at junctions thermally coupled to said electrode to form first and second thermoelectric junctions, said first and second thermojunctions generating first and second thermoelectric potentials respectively;
and
a fourth conductor of said first material electrically coupled to said electrode;
first, second and third voltage variable divider means, for generating, at an output terminal thereof, a signal indicative of a controlled fraction of the potential difference between first and second input terminals thereof;
said first voltage divider means first and second input terminals being connected to said first conductor and said third conductor respectively
said second voltage divider means first and second input terminals being connected to said second conductor and third conductor respectively;
said third voltage divider means first and second input terminals being connected to said first voltage divider means output terminal and said second voltage divider means output terminal, respectively;
a resistance;
said fourth conductor being coupled through said resistance to said indicator means;
said first and second probe third voltage divider output terminals also being coupled to said indicator means, electrically coupling said probes in series opposition;
said apparatus further comprising means for adjusting said first and second probe first voltage divider means in synchronism;
means for adjusting said first and second probe second voltage divider means in synchronism;
and
means for adjusting said first and second probe third voltage divider means in synchronism.

12 more elements

said first and second probes each include an electrode of a first thermally conductive material, a first conductor of a second material, a first thermopile including conductors of a second material and a third material, a second thermopile including conductors of said first and third materials;
said first conductor, first thermopile and second thermopile being electrically coupled to one another at junctions thermally coupled to said electrode to form first, second, and third thermoelectric junctions generating first, second and third thermoelectric potentials respectively,
and
a second conductor of said third material electrically coupled to said electrode;
first and second variable voltage divider means each for generating a signal indicative of a controlled fraction of the potential at its input terminal thereof;
third variable voltage divider means for generating at an output terminal thereof a signal indicative of a controlled fraction of the potential difference between first and second input terminals thereof;
first switch means for coupling said input terminal of said first variable voltage divider means to either said first conductor or to said first thermopile;
second switch means for coupling said input terminal of said second voltage divider to said conductor of said first material of said second thermopile or to said conductor of said third material of said second thermopile, said first and second switch means operating in synchronism such that in a first position said input terminals of said first and second variable voltage dividers are coupled respectively to said first conductor and said conductor of said first material of said second thermopile in a second position, said input terminals of said first and second variable voltage dividers are coupled respectively to said first thermopile and to said conductor of said third material of said second thermopile;
said input terminals of said third voltage divider means coupled to said output terminals of said first and second voltage divider means;
a resistor;
said second conductor being coupled through said resistor to said indicator means;
said first and second probe third voltage divider output terminals also being coupled to said indicator means, electrically coupling said probes in series opposition;
said apparatus further comprising means for adjusting said first and second probe first voltage divider means in synchronism;
means for adjusting said first and second probe second voltage divider means in synchronism;
and
means for adjusting said first and second probe third voltage divider means in synchronism.

13 more elements

Dependencies are inferred from the claim text.

Metal-alloy thermoelectric characteristic analyzer

Life of this patent

Metal-alloy thermoelectric characteristic analyzer

Life of this patent

Abstract

Claims26