A protective tube for sealed introduction into a process vessel at a process vessel port, the protective tube comprising a sealing base element which is connected onto the process vessel port and an elongate body with a bore. The elongate body comprises a closed distal end and an open proximal end, which is sealingly connected onto the sealing base element. The protective tube also comprises a receiving part, which is connected or attached onto the elongate body inside the process vessel so as to receive and hold a secondary temperature sensor from inside the process vessel. In addition, a reference temperature sensor is insertable into the bore from outside the process vessel. Also provided is a temperature measurement arrangement and a method for a temperature measurement in a process vessel.

A protective tube for sealed introduction into a process vessel at a process vessel port, the protective tube comprising a sealing base element which is connected onto the process vessel port and an elongate body with a bore. The elongate body comprises a closed distal end and an open proximal end, which is sealingly connected onto the sealing base element. The protective tube also comprises a receiving part, which is connected or attached onto the elongate body inside the process vessel so as to receive and hold a secondary temperature sensor from inside the process vessel. In addition, a reference temperature sensor is insertable into the bore from outside the process vessel. Also provided is a temperature measurement arrangement and a method for a temperature measurement in a process vessel.

There is described a method of detecting failure in an array of thermocouples connected in parallel. The method comprising: during an operation mode of the array of thermocouples, measuring a voltage V across the array of thermocouples, the voltage V associated with a temperature T; during a failure detection mode of the array of thermocouples, shunting the array of thermocouples, and measuring a shunt voltage Vs occurring across a resistive element connected in series with the array of thermocouples; comparing the shunt voltage Vs to an expected shunt voltage Vs_exp for the array of thermocouples at the temperature T; and generating a failure signal indicative of a detected failure in the array of thermocouples when the shunt voltage Vs deviates from the expected shunt voltage Vs_exp by more than a deviation threshold.

A temperature input unit includes a disconnection detection circuit that measures a temperature of a measurement target with at least one of a thermocouple or a temperature measurement resistor and feeds a disconnection detection current for disconnection detection to the thermocouple and a compensating wire connected to the thermocouple. A controller controls, before measuring the temperature of the measurement target with the thermocouple, a terminal switch and an input circuit switch to connect the compensating wire to a temperature measurement resistor input circuit and an A/D converter, and calculates a predicted value of a voltage drop resulting from resistance of the compensating wire occurring in response to the disconnection detection current. The controller controls the terminal switch and the input circuit switch to connect the compensating wire to a thermocouple input circuit and the A/D converter, and subtracts the predicted value from a measured value of the thermoelectromotive force detected by the thermocouple input circuit to calculate a corrected measured value of the thermoelectromotive force.

A temperature input unit includes a disconnection detection circuit that measures a temperature of a measurement target with at least one of a thermocouple or a temperature measurement resistor and feeds a disconnection detection current for disconnection detection to the thermocouple and a compensating wire connected to the thermocouple. A controller controls, before measuring the temperature of the measurement target with the thermocouple, a terminal switch and an input circuit switch to connect the compensating wire to a temperature measurement resistor input circuit and an A/D converter, and calculates a predicted value of a voltage drop resulting from resistance of the compensating wire occurring in response to the disconnection detection current. The controller controls the terminal switch and the input circuit switch to connect the compensating wire to a thermocouple input circuit and the A/D converter, and subtracts the predicted value from a measured value of the thermoelectromotive force detected by the thermocouple input circuit to calculate a corrected measured value of the thermoelectromotive force.

A temperature sensing assembly includes a sheath defining an interior space, a first temperature sensor and a second temperature sensor. The first temperature sensor has first and second conductors extending within the interior space of the sheath and joined at a first junction point. The first conductor is constructed of a first material and the second conductor is constructed of a second material that is different than the second material. The second temperature sensor has third and fourth conductors extending within the interior space of the sheath and joined at a second junction point. The third conductor is constructed of a third material and the fourth conductor is constructed of a fourth material that is different than the fourth material. The first material is different than each of the third and fourth materials. The first junction point is adjacent to the second junction point.

A temperature sensing assembly includes a sheath defining an interior space, a first temperature sensor and a second temperature sensor. The first temperature sensor has first and second conductors extending within the interior space of the sheath and joined at a first junction point. The first conductor is constructed of a first material and the second conductor is constructed of a second material that is different than the second material. The second temperature sensor has third and fourth conductors extending within the interior space of the sheath and joined at a second junction point. The third conductor is constructed of a third material and the fourth conductor is constructed of a fourth material that is different than the fourth material. The first material is different than each of the third and fourth materials. The first junction point is adjacent to the second junction point.

A temperature sensing assembly includes a sheath defining an interior space, a first temperature sensor and a second temperature sensor. The first temperature sensor has first and second conductors extending within the interior space of the sheath and joined at a first junction point. The first conductor is constructed of a first material and the second conductor is constructed of a second material that is different than the second material. The second temperature sensor has third and fourth conductors extending within the interior space of the sheath and joined at a second junction point. The third conductor is constructed of a third material and the fourth conductor is constructed of a fourth material that is different than the fourth material. The first material is different than each of the third and fourth materials. The first junction point is adjacent to the second junction point.

A temperature sensing assembly includes a sheath defining an interior space, a first temperature sensor and a second temperature sensor. The first temperature sensor has first and second conductors extending within the interior space of the sheath and joined at a first junction point. The first conductor is constructed of a first material and the second conductor is constructed of a second material that is different than the second material. The second temperature sensor has third and fourth conductors extending within the interior space of the sheath and joined at a second junction point. The third conductor is constructed of a third material and the fourth conductor is constructed of a fourth material that is different than the fourth material. The first material is different than each of the third and fourth materials. The first junction point is adjacent to the second junction point.

A temperature sensing assembly includes a sheath defining an interior space, a first temperature sensor and a second temperature sensor. The first temperature sensor has first and second conductors extending within the interior space of the sheath and joined at a first junction point. The first conductor is constructed of a first material and the second conductor is constructed of a second material that is different than the second material. The second temperature sensor has third and fourth conductors extending within the interior space of the sheath and joined at a second junction point. The third conductor is constructed of a third material and the fourth conductor is constructed of a fourth material that is different than the fourth material. The first material is different than each of the third and fourth materials. The first junction point is adjacent to the second junction point.