Non-invasive process fluid temperature indication with reduced error

Abstract

A process fluid temperature estimation system includes a mounting assembly, a sensor capsule, measurement circuitry, and a controller. The mounting assembly is configured to mount the process fluid temperature estimation system to an external surface of a process fluid conduit. The sensor capsule has an end that is configured to contact the external surface of the process fluid conduit to form an interface having a contact region and an air gap. The sensor capsule also has at least one temperature sensitive element disposed therein. The 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 at least process fluid conduit skin temperature information. The controller is coupled to the measurement circuitry and is configured to obtain the process fluid conduit skin temperature information from the measurement circuitry and to obtain reference temperature information. The controller is configured to obtain a heat flow parameter related to the air gap of the interface and to employ a heat transfer calculation with the process fluid conduit skin temperature information, reference temperature information, and heat flow parameter to generate an estimated process fluid temperature output.