# US 12,768,729 B2 · Non-invasive process fluid temperature indication

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- Number: US 12,768,729 B2
- Document ID: US12768729B2
- Status: Granted
- Kind: B2
- Application number: 16/146,152
- Filed: 2018-09-28
- Published: 2020-04-02
- Granted: 2026-10-20
- Earliest claimed: 2018-09-28
- Assignees: Rosemount Inc.
- Applicants: Rosemount Inc.
- Inventors: Jason H. Rud; Steven R. Trimble
- Web page: https://patentgrep.com/patent/US12768729B2

## CPC

- G01K 17/08: based upon measurement of temperature difference {or of a temperature}
- G01K 1/143: for measuring surface temperatures
- G01K 13/02: for measuring temperature of moving fluids or granular materials capable of flow
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)

## Abstract

A process fluid temperature estimation system includes a mounting assembly configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit. A sensor capsule has at least one temperature sensitive element disposed therein. Measurement circuitry is coupled to the sensor capsule and configured to detect an electrical characteristic of the at least one temperature sensitive element that varies with temperature and provide sensor capsule temperature information. A controller is coupled to the measurement circuitry and is configured to obtain a reference temperature and employ a heat transfer calculation with the reference temperature, the sensor capsule temperature information and the known thermal conductivity of the process fluid conduit to generate an estimated process fluid temperature output. The reference temperature is obtained from a reference temperature source selected from the group consisting of: a terminal temperature sensor, process communication, an electronics temperature sensor, an external ambient temperature sensor, and an estimation based on known thermal properties.

## Claims

### Claim 1

A process fluid temperature estimation system comprising:
a mounting assembly configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit having a known thermal conductivity;
a sensor capsule having at least one temperature sensitive element disposed therein, the sensor capsule being disposed to position the at least one temperature sensitive element proximate the external surface of the process fluid conduit;
a terminal temperature sensor;
measurement circuitry coupled to the sensor capsule and the terminal temperature sensor, the measurement circuitry being configured to detect an electrical characteristic of the at least one temperature sensitive element and the terminal temperature sensor that varies with temperature;
a controller coupled to the measurement circuitry, the controller being configured to obtain at least one external surface temperature measurement from the measurement circuitry and to obtain a reference temperature from the terminal temperature sensor and to employ a heat flow calculation with the reference temperature, the external surface temperature measurement, and the known thermal conductivity of the process fluid conduit to generate an estimated process fluid temperature output; and
backup logic configured to monitor status of the terminal temperature sensor and selectively provide a second reference temperature measurement from an electronics temperature sensor to the controller.

### Claim 2 (depends on 1)

The process fluid temperature estimation system of claim 1, wherein the backup logic is configured to detect a malfunction of the terminal temperature sensor, and automatically provide the second reference temperature measurement to the controller.

### Claim 3 (depends on 1)

The process fluid temperature estimation system of claim 1, and further comprising communication circuitry coupled to the controller and configured communicate in accordance with a process communication loop protocol.

### Claim 4 (depends on 3)

The process fluid temperature estimation system of claim 3, wherein the communication circuitry is configured to communicate wirelessly.

### Claim 5 (depends on 1)

The process fluid temperature estimation system of claim 1, wherein the sensor capsule has an endcap, and at least one temperature sensitive element is thermally coupled to the endcap.

### Claim 6

A process fluid temperature estimation system comprising:
a mounting assembly configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit;
a sensor capsule having at least one temperature sensitive element disposed therein;
a terminal temperature sensor;
measurement circuitry coupled to the sensor capsule and configured to detect an electrical characteristic of the at least one temperature sensitive element that varies with temperature and provide sensor capsule temperature information;
communication circuitry configured to receive a reference temperature using process communication;
a controller coupled to the measurement circuitry and configured to employ a heat flow calculation with the reference temperature, the sensor capsule temperature information and the known thermal conductivity of the process fluid conduit to generate an estimated process fluid temperature output; and
backup logic configured to monitor status of the reference temperature and selectively provide a second reference temperature measurement to the controller based on a terminal temperature sensor signal.