Modified Thermocouple Assembly

A method for measuring or determining temperatures comprising the steps of:

• placing an isothermal terminal block A between a cold junction terminal block B and a temperature measurement zone Z;
• extending x pairs of thermoelements TE between blocks A and B, wherein each pair of TE comprises a positive leg and a negative leg, and wherein each positive leg and each negative leg is attached to a separate terminal in block B;
• forming a thermocouple TCa in block A with one pair of TE;
• attaching each of the remaining legs to a separate terminal in block A, wherein a first terminal in block A has a positive leg and a last terminal in block A has a negative leg;
• forming (2x−2) thermocouples in zone Z by two dissimilar thermocouple wires that extend from the thermocouple TCa or from one of the terminals in block A;
• connecting a smart multiplexer to each terminal in block B, wherein the multiplexer is configured to:
• obtain and use a cold junction temperature for block B;
• obtain and use a temperature measured by thermocouple TCa;
• isolate a circuit for each of the thermocouples in zone Z;
• and
• determine a temperature measured by each of the thermocouples in zone Z.

A kit comprising:

• a first terminal block having a terminal TRM3, a terminal TRM4 and a thermocouple TC3 for measuring a temperature T3,
• a second terminal block having terminals TRM1, TRM2, TRM5 and TRM6;
• and
• a smart multiplexer operatively connected to each of the terminals TRM1, TRM2, TRM5 and TRM6,
• wherein the smart multiplexer is configured to isolate desired pairs of the terminals and to measure a voltage difference between the terminals in a desired pair, and
• wherein the smart multiplexer is configured to determine a temperature that correlates to the measured voltage difference for user-specified thermoelements received on or in the terminals;
• and
• instructions informing a user to:
• connect terminal TRM3 in the first terminal block to terminal TRM5 in the second terminal block using a thermoelement having a composition of matter A,
• connect thermocouple TC3 in the first terminal block to terminal TRM1 in the second terminal block using a thermoelement having the composition of matter A,
• connect thermocouple TC3 in the first terminal block to terminal TRM2 in the second terminal block using a thermoelement having a composition of matter B, wherein composition of matter B is not the same as composition of matter A, and
• connect terminal TRM4 in the first terminal block to terminal TRM6 in the second terminal block using a thermoelement having the composition of matter B.

A thermowell-thermocouple assembly for measuring temperature inside a structure, wherein the structure comprises a commercial or industrial vessel, unit or machine, and wherein the structure has a mounting flange for receiving and holding the thermowell-thermocouple assembly, the thermowell-thermocouple assembly comprising:

• a thermowell tube received in and engaged directly or indirectly with the mounting flange, wherein the thermowell tube has a distal end for receipt inside the structure and a proximal end that remains outside the structure;
• a thermocouple head (14) received on the proximal end of the thermowell tube, wherein the thermocouple head (14) comprises a terminal block 14 that has terminals;
• a smart multiplexer connected to the terminals in terminal block 14;
• and
• a thermocouple assembly received in the thermowell tube, wherein the thermocouple assembly comprises:
• a thermocouple tip having a first thermocouple (TC1) for determining a first temperature (T1) and a second thermocouple (TC2) for determining a second temperature (T2), wherein the first thermocouple (TC1) is formed at a junction of first and second thermoelements (TE1 and TE2), wherein the second thermocouple (TC2) is formed at a junction of third and fourth thermoelements (TE3 and TE4);
• a terminal block (12);
• a third thermocouple (TC3) on or in the terminal block (12) for determining a third temperature (T3), wherein the third thermocouple (TC3) is formed at a junction of fifth and sixth thermoelements (TE5 and TE6), wherein the fifth thermoelement (TE5) extends from the third thermocouple (TC3) to a first terminal (TRM1) in the terminal block (14), wherein the sixth thermoelement (TE6) extends from the third thermocouple (TC3) to a second terminal (TRM2) in the terminal block (14),
• wherein the second thermoelement (TE2) extends from the first thermocouple (TC1) to the third thermocouple (TC3),
• wherein the third thermoelement (TE3) extends from the second thermocouple (TC2) to the third thermocouple (TC3),
• wherein the first thermoelement (TE1) extends from the first thermocouple (TC1) to a third terminal (TRM3) in the terminal block (12),
• wherein the fourth thermoelement (TE4) extends from the second thermocouple (TC2) to a fourth terminal (TRM4) in the terminal block (12),
• wherein a strand of fifth thermoelement material (TE5) extends from the third terminal (TRM3) in the terminal block (12) to a fifth terminal (TRM5) in the terminal block (14), and
• wherein a strand of sixth thermoelement material (TE6) extends from the fourth terminal (TRM4) in the terminal block (12) to a sixth terminal (TRM6) in the terminal block (14).

The thermowell-thermocouple assembly of claim wherein the smart multiplexer is configured to:

• determine a reference temperature (T4) at the terminal block (14);
• measure a voltage difference (VD12) between the first and second terminals (TRM1 and TRM2);
• determine or estimate the third temperature (T3) using the voltage difference (VD12) between the first and second terminals (TRM1 and TRM2) and the reference temperature (T4) at the thermocouple head (14);
• measure a voltage difference (VD15) between the first and fifth terminals (TRM1 and TRM5);
• determine or estimate the first temperature (T1) using the voltage difference (VD15) between the first and fifth terminals (TRM1 and TRM5) and the third temperature (T3) at the terminal block (12);
• measure a voltage difference (VD26) between the second and sixth terminals (TRM2 and TRM6);
• and
• determine or estimate the second temperature (T2) using the voltage difference (VD26) between the second and sixth terminals (TRM2 and TRM6) and the third temperature (T3) at the terminal block (12).

A thermocouple assembly comprising:

• a thermocouple tip having a first thermocouple (TC1) for determining a first temperature (T1) and a second thermocouple (TC2) for determining a second temperature (T2), wherein the first thermocouple (TC1) is formed at a junction of first and second thermoelements (TE1 and TE2), wherein the second thermocouple (TC2) is formed at a junction of third and fourth thermoelements (TE3 and TE4);
• an isothermal zone (12);
• a third thermocouple (TC3) in the isothermal zone (12) for determining a third temperature (T3), wherein the third thermocouple (TC3) is formed at a junction of fifth and sixth thermoelements (TE5 and TE6), wherein the fifth thermoelement (TE5) extends from the third thermocouple (TC3) to a first terminal (TRM1) in a terminal block (14), wherein the sixth thermoelement (TE6) extends from the third thermocouple (TC3) to a second terminal (TRM2) in the terminal block (14),
• wherein the second thermoelement (TE2) extends from the first thermocouple (TC1) to the third thermocouple (TC3),
• wherein the third thermoelement (TE3) extends from the second thermocouple (TC2) to the third thermocouple (TC3),
• wherein the first thermoelement (TE1) extends from the first thermocouple (TC1) to a third terminal (TRM3) in the isothermal zone (12),
• wherein the fourth thermoelement (TE4) extends from the second thermocouple (TC2) to a fourth terminal (TRM4) in the isothermal zone (12),
• wherein a strand of fifth thermoelement material (TE5) extends from the third terminal (TRM3) in the isothermal zone (12) to a fifth terminal (TRM5) in the terminal block (14), and
• wherein a strand of sixth thermoelement material (TE6) extends from the fourth terminal (TRM4) in the isothermal zone (12) to a sixth terminal (TRM6) in the terminal block (14).